The alkaline electrolysis of water for hydrogen production technology still poses risks of component corrosion, pipeline structural degradation, and hydrogen oxygen mixing and leakage during large-scale application, posing a threat to system operation safety. By analyzing the structural composition and working mechanism of the alkaline electrolysis water hydrogen production system, the key components and reasons affecting the safety of hydrogen production are identified. In response to the insufficient active sites and poor stability of electrode catalysts at high current densities, a method of using three-dimensional electrode structure design or constructing hydrophilic and hydrophobic interfaces is proposed. There is an urgent need to develop high-performance membrane materials to address the risk of hydrogen oxygen mixing caused by insufficient hydrophilicity and mechanical strength defects in membrane materials. The study also revealed the impact mechanism of various operating parameters and fluctuation conditions on gas purity, pointing out the shortcomings of current methods for improving gas purity by adjusting a single parameter. It provides theoretical support for the safety of large-scale industrial alkaline water electrolysis to produce hydrogen.

With the rapid development of new energy under the “dual carbon” goals, molten salt-assisted high-value conversion of biomass has attracted widespread attention. Biomass, as the fourth largest energy source globally and the sole renewable carbon resource, stands as a prominent candidate for replacing traditional fossil fuels. Thermochemical conversion technologies enable the transformation of biomass into value-added products including bio-oil, syngas, and carbon materials, with molten salts serving as reaction media to enhance conversion efficiency and product value. The exceptional heat transfer capabilities of molten salts create optimal reaction environments for fast pyrolysis, significantly improving bio-oil yield. The strong catalytic activity of abundant alkali metal ions in molten salts facilitates chemical bond cleavage and formation, enabling targeted regulation of bio-oil composition and directional enrichment of high-value chemicals. During the gasification process, these alkali metal ions enhance gasification efficiency and promote syngas production, while the tunable composition and types of molten salts establish an optimal reaction environment for the production of syngas with controllable ratios. Furthermore, the etching effects and redox reactions between molten salts and carbon matrices optimize the physicochemical properties of carbon materials, particularly porosity. The innovative thermoelectric synergistic processes in molten salt media further elevate the added value of biochar products. This review systematically summarizes recent advancements in molten salt-assisted valorization of biomass, elucidates the critical roles and mechanisms of molten salts in different product-oriented conversion scenarios, and outlines the challenges and imperative research directions for molten salt-based thermochemical technologies.

Deep eutectic solvents (DES), as a new, green, and efficient solvent system, have demonstrated significant advantages in the cationic modification of plant fibers. This paper systematically reviews recent research progress on DES in the cationic modification of plant fibers, with a focus on the chemical processes, modification mechanisms, and application performance of binary and ternary TDES solvents. First, the effects of different pretreatment methods (physical, chemical, and enzymatic) on improving fiber accessibility and reactivity are analyzed. Subsequently, the mechanisms of binary DES solvent systems—such as carboxylic acid-based, urea-based, and glycerol-based systems—in fiber cationization are elaborated in detail. Additionally, research findings on ternary DES (TDES) solvents, which further enhance modification efficiency through multicomponent synergistic effects, are summarized. Studies have shown that DES solvent efficiently introduces quaternary ammonium groups into cellulose molecules by breaking the hydrogen bond network of cellulose, improving the dispersion of fibers and increasing the yield of nanofibers. The modified cationized fibers have broad applications in pulping and papermaking, nanomaterials, wastewater treatment, and biomedicine. Furthermore, this paper discusses current technical challenges in DES systems, including component interaction mechanisms, solvent recovery, and industrial-scale applications, while proposing future research directions. The findings provide a theoretical foundation and technical reference for the high-value utilization of plant fibers.

Chlorofluoroethylene (HCFO-1131), containing fluorine atom, chlorine atom, and CC double bond, exhibits a unique molecular configuration that endows it with exceptional physicochemical properties. As the core monomer (7%—10% by mass) for the synthesis of ferroelectric/piezoelectric fluorinated polymers P(VDF-TrFE-CFE), this material shows great application potential in the fields of smart sensors, solid-state refrigeration and new energy devices, and the market demand is expected to grow exponentially in the future. This paper reviews the synthetic pathways of HCFO-1131 and its application in intelligence materials. Current synthetic routes primarily involve: halogen exchange reactions of chlorinated olefins, zinc-mediated reductive dehalogenation of fluorochlorocarbons, and dehydrochlorination of polyhalogenated hydrocarbons. However, these methodologies suffer from intrinsic drawbacks such as slow conversions, low selectivities, and large amount of waste, severely limiting their scalability in contemporary manufacturing. There is an urgent need to optimize existing processes or develop novel synthetic strategies to achieve green and efficient preparation of HCFO-1131, facilitating its applications in cutting-edge materials.

R513A has attracted much attention due to its good environmental characteristics and cycling performance for refrigeration and heat pump systems. Based on the isovolumetric saturation method, the phase equilibrium of R513A and R134a in polyvinyl ether (PVE) lubricants was investigated. The experimental temperature range was 283.15—343.15 K and the pressure range was 0—1.6 MPa. In addition, the change in viscosity of the lubricating oils was determined by using a viscometer after the dissolution of the refrigerants. The results showed that the solubility of both refrigerants in PVE32 (FVC 32D) oil decreased with increasing temperature and increased with increasing pressure when the temperature was constant. In addition, the solubility data were correlated using the non-random two liquid (NRTL) equation and the experimental data were in good agreement with the NRTL model. As the solubility of the refrigerant in the oil increased, the viscosity of the mixture initially decreased sharply and then leveled off. The refrigerant dissolved in oil reduces the viscosity of the lubricant considerably, but the difference between the two refrigerants is not significant. Both refrigerants, R513A and R134a, are very well adapted to the PVE lubricant, and R513A is a suitable alternative refrigerant to R134a in systems where PVE lubricants are applied.

The horizontal twin-shaft kneading devolatilizer has a complex structure and its blades are interlaced in the overlapping area, and its flow film-forming characteristics are still lacking in-depth understanding. This paper establishes a facile numerical simulation method using the overset mesh method combined with VOF model, and reports the film formation and surface renewal characteristics of the kneading devolatilizers at viscosities of 50—1000 Pa∙s and rotating speeds of 1—5 r·min^-1 at periodic steady state. The simulated film thickness data agree well with experimental measurements using a visualization device. An asymmetric liquid level is formed within the reactor, and the asymmetry is affected by both the viscosity and the rotating speed. The film area generally increases with increasing the rotating speed. At a given speed, the film area firstly increases significantly and then levels off with increasing the viscosity. Shear-stretching between the kneading rods creates a localized high-speed zone, which helps to enhance the mixing efficiency. Surface renewal mainly occurs in the kneading rods drag-out, kneading, front and back sides of the E-shaped rods, and drag-in regions. The average surface renewal frequency is linearly related to the rotating speed. The findings above could be of guidance in the rational design and process optimization of kneading reactors.

Super-long gravity heat pipe (SLGHP) has shown broad application prospects in the field of geothermal energy development due to its excellent heat transfer capacity and pump-free drive characteristics. However, in practical applications, the start-up process of SLGHP involves complex phase change and heat transfer mechanisms, especially regarding the temperature response and thermal equilibrium following working fluid injection, which remain inadequately understood. This study investigates the liquid-injection start-up process, heat extraction start-up characteristics, and the influence of heat pump start-up modes on the operational performance of the SLGHP-heat pump heating system through combined experimental measurements and numerical simulations. Fiber optic temperature sensing was employed to monitor the dynamic evolution of wall temperature during the injection process. The results indicate that the temperature inflection point formed during the downward wetting of ammonia correlates strongly with the injection depth and can serve as a dynamic indicator of fluid distribution. Upon completion of injection, the axial temperature gradient of the heat pipe decreases from 18.4℃/km to 2℃/km, significantly improving thermal uniformity. The numerical model exhibits less than 3% deviation from experimental data, validating the predictive accuracy of working fluid distribution and temperature field evolution. Moreover, an engineering criterion based on the temperature deviation between wellhead vapor and formation average temperature after 12 h of injection is proposed, enabling assessment of the start-up completion without the need for external temperature sensors. Further analysis reveals that during cold start-up, the discharge pressure of the heat pump increases from 0.55 MPa to 1.06 MPa, with heating output reaching 900 kW within 1 h and a COP stabilizing at 6.5. In contrast, during thermal start-up, the presence of residual thermal energy in the system shortens the time required to reach a relatively stable state by 28%. This study elucidates the heat transfer mechanism during the start-up phase of the SLGHP-heat pump system, providing valuable insights for the optimized design and stable operation of SLGHP geothermal systems.

In order to solve the problem of particulate fouling in the heat exchanger channel, the anti-fouling effect characteristics of the perforated vortex generator in the pulsating channel were studied by the experimental bench built. First, the particulate fouling characteristics of four different types of channels were compared, and the particulate deposition characteristics of different perforated rectangular wing vortex generator in the pulsating channel were studied in depth, and the influence of the frontal angle of the perforated rectangular wing vortex generator on the particulate fouling was analyzed in detail. The results show that compared with the smooth channel, the anti-fouling effect rate of the pulsating channel is 15.7%, the anti-fouling effect rate of the pulsating + rectangular wing is 41.2%, and the anti-fouling effect rate of the pulsating + perforated rectangular wing channel is the best, and the anti-fouling effect rate is 47.5%. In the scope of this study, three different airfoil types (delta wing, trapezoidal wing, rectangular wing) with open holes are compared, and it is found that the vortex generator with open holes and rectangular wings has the best anti-fouling effect. In addition, when the angle is less than 90°, the fouling resistance gradually decreases with the increase of the angle of the perforated rectangular wing vortex generator, and when the angle is 90°, the fouling resistance is minimized.

A lattice Boltzmann method with Bhatnagar-Gross-Krook (LBM-BGK) equation suitable for simulating thermal transpiration phenomena under high Knudsen number (Kn) conditions in transitional flow regime was established. The relaxation coefficient and velocity slip boundary conditions were modified as well. By incorporating temperature jumps into the velocity slip boundary conditions, the D2Q9 model was employed to simulate the temperature, pressure, streamline, and velocity distributions for air in a long straight microchannel under transitional flow regime conditions. The results show that: with increasing Kn, the temperature and pressure distributions at the center of the microchannel become distorted, transitioning from linear to nonlinear distributions. Simultaneously, the streamlines in the longitudinal cross-section deviate from parallel, exhibiting increasing randomness. A higher Kn signifies a more rarefied flow state corresponding to a larger pressure difference, which shows that a more rarefied flow state is more beneficial to raise pressure differences. With increasing Kn, the dimensionless velocity increase at the center of the microchannel is significantly lower than that near the wall, indicating a more pronounced velocity slip effect. In the high Kn regime, the average dimensionless slope of slip velocity is closer to Cercignani's results. The simulation findings provide valuable insights for the fields of mesoscale flow and rarefied gas dynamics.

Externally heated rotary kilns exhibit promising application prospects in the petroleum coke carbonization process, a critical step in the preparation of artificial graphite for lithium-ion battery anodes, due to its advantages of uniform heating, precise temperature control, energy efficiency, and environmental friendliness. The lack of understanding of the heat transfer performance law of the rotary kiln wall bed during the carbonization of petroleum coke restricts the precise design and energy-saving and low-carbon operation of this type of rotary kiln. This study utilized an electrically heated rotary kiln experimental system to investigate the effects of operational parameters on the wall-to-bed heat transfer coefficients of petroleum coke and quartz sand particles. The results indicate that as the filling rate increases, the wall-to-bed heat transfer coefficients of both quartz sand and petroleum coke particles decrease to varying degrees. Increasing the rotational speed significantly enhances the heat transfer coefficient for quartz sand particles, but has limited effect on petroleum coke particles. This is primarily due to quartz sand particles exhibiting rolling motion while petroleum coke particles undergo sliding motion. The heat transfer coefficient under sliding motion is significantly lower than that under rolling motion. Installing strip structures on the inner wall of the kiln can induce regular mixing of the petroleum coke particle bed, thereby enhancing heat transfer by approximately 70%—180%.

The development of flexible electronic devices has put forward the demand for microchannel heat exchangers made of elastically deformable materials. The condensation flow of FC-72 in rectangular microchannels made of PDMS with deformable soft wall was studied. The microchannels have a width of 300 μm and a height of 150 μm. Flow mass fluxes of 290 and 482 kg/(m²‧s) and vapor mass quality varying from 0.1 to 0.9 were experimentally studied. The images of the condensation flow patterns were collected using a fast camera. The data on soft wall deformation was measured using a white light confocal displacement sensor. The wall thickness increasing appears for intermittent flow. This wall thickening gets more significant with increasing inlet vapor mass quality and mass flux. By analyzing the curvature of the liquid-vapor interface, it is found that surface tension is not sufficient to cause the wall deformation observed in the experiments. This soft wall thickening phenomenon is caused by the local pressure drop in the liquid slug. This pressure drop occurs as a result of shrinking elongated bubbles due to the vapor vanishing during the condensation process. Therefore, if condensation is strong enough, it may induce a sudden local pressure drop in the liquid slug, causing the soft wall to move towards the channel inside. A theoretical model is proposed to predict the deformation of this soft wall. The results of the model are in good agreement with the measured deformation data for higher mass flux.

Structural optimization is one of the important means to improve the output performance of proton exchange membrane fuel cells (PEMFC). Therefore, a new bionic droplet flow channel is proposed and compared with the sinusoidal flow channel and the straight flow channel to analyze their effects on the performance of PEMFC. Through the analysis of polarization curves,oxygen and water distribution, membrane current density, flow velocity and pressure drop, the results show that under the condition of the maximum depth of the bionic droplet flow channel being 0.65 mm and the number of cycles being 8, the current density of the bionic droplet flow channel is increased by 2.1% and 6.1% compared with the sinusoidal flow channel and the straight flow channel, respectively. In addition,the bionic droplet flow channel has significant improvements in oxygen concentration, membrane current density and average flow velocity compared with the sinusoidal flow channel and the straight flow channel, and the water content is lower than that of the two. This further indicates that the bionic droplet flow channel has the characteristics of uniform reaction gas concentration, strong water removal ability and high output performance.

Herein, a series of Ni-Ag/SiO₂ bimetallic catalysts with varying metal loadings were fabricated to investigate the synergistic mechanism of active sites in the selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG). The morphology and active site structures of the catalysts were analyzed in detail by nitrogen physical adsorption, hydrogen temperature-programmed reduction, X-ray diffraction, and X-ray photoelectron spectroscopy. The results revealed that the Ni species in the prepared Ni-Ag/SiO₂ bimetallic catalyst mainly existed in the layered nickel phyllosilicate structure, and Ag particles were supported on its surface. Catalytic performance tests, combined with in situ Fourier-transform infrared spectroscopy and temperature-programmed desorption experiments, found that bimetallic catalysts with different Ni/Ag ratios exhibited significant differences in the adsorption and activation behavior of DMO and H₂. Specifically, increasing Ni content promotes the activation of DMO, while increasing Ag content is beneficial for H₂ activation, indicating that Ni⁰/Ni ^δ+ interface sites and Ag species of Ni-Ag/SiO₂ bimetallic catalysts are responsible for the activations of DMO and H₂, respectively. By optimizing the Ni/Ag (mass ratio) to 5∶1, the catalyst achieved a remarkable DMO conversion of 99.6% and MG selectivity of 91.5% under mild reaction conditions, with no significant performance degradation observed over 350 h of stability test. This work provides critical insights into the design of efficient catalysts for the conversion of coal-based syngas to MG, and also highlights a rational strategy for balancing substrate activation and hydrogen in heterogeneous catalysis.

Four precipitating agents (ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, and urea) were selected to synthesize CeO₂-Al₂O₃ supports via a precipitation method, using high-surface-area Al₂O₃ as a non-soluble aluminum source and Ce(NO₃)₃·6H₂O as a cerium precursor. Pt/CeO₂-Al₂O₃ catalysts were subsequently prepared by Pt impregnation to investigate the effect of precipitating agents on CO catalytic oxidation performance. Characterization results show that the catalyst prepared by urea uniform precipitation method exhibits the best activity, which is attributed to the enhanced Pt-CeO₂ interface interaction. The type of precipitant affects the dispersion, distribution uniformity, morphology of CeO₂, and the interaction between Pt and CeO₂ by altering crystallization kinetics and precursor types. In the urea homogeneous precipitation process with the presence of Al₂O₃, the slow precipitation mechanism within confined channels promotes both uniform distribution and high dispersion of nanorod-like CeO₂ particles inside the Al₂O₃ pores. This approach avoids the aggregation and surface enrichment of spherical CeO₂ nanoparticles on the outer surface of Al₂O₃ caused by rapid precipitation when using ammonia as a precipitant. Thereby, it strengthens the interaction between Pt and CeO₂, ultimately achieving enhanced catalytic performance.

To obtain a Co-based catalyst with high-activity for CO₂-assisted ethane dehydrogenation to ethylene, a series of Co/SSZ-13 catalysts were prepared by ion-exchange and impregnation methods. Raman and XPS were employed to investigate the coordination environment and valence state of Co species, while reaction pathway analysis revealed the synergistic mechanism of highly dispersed dual-site Co ^{species in catalyzing the reaction. The additional impregnation step following ion-exchange significantly enhanced catalytic activity, increasing ethylene yield from 23.46% to 38.20% at 675℃. Ion-exchange method primarily anchored highly dispersed Co(Ⅱ) species on SSZ-13, which exhibited excellent ethane direct dehydrogenation (EDH) activity. Subsequent impregnation increased the content of Co₃O₄, which promoted the reverse water-gas shift (RWGS) reaction because of the in situ reduction to Co0 during reaction evaluation and synergistically improved the apparent oxidative dehydrogenation (ODHE) performance with Co(Ⅱ). However, excessive Co₃O₄ content induced excessive Co0 species during catalytic evaluation process, leading to severe side reactions and reduced selectivity to ethylene. This work elucidates the cooperative mechanism of dual-site Co species and demonstrates the necessity of precisely tuning the ratio of dual-sites of the fresh catalysts to balance activity and stability.}

Electrolysis of water to produce hydrogen has the advantages of being green and efficient, but is limited by the slow kinetics and high cost of precious metal catalysts, and it is urgent to develop efficient and stable non-precious metal catalysts. An Fe-doped cobalt hydrogen phosphite [Fe-Co(H₂PO₂)₂] catalyst is synthesized via a one-step electrodeposition method on a nickel foam substrate. Structural analyses reveal that Fe-Co(H₂PO₂)₂ adopts a self-supported microspherical architecture with an amorphous nature, significantly increasing the exposure of electrochemically active sites. Moreover, Fe-doping effectively modulates the electronic structure of Co(H₂PO₂)₂, enhancing charge transfer efficiency and accelerating electrocatalytic reaction kinetics. The electrochemical test results show that the overpotentials of hydrogen and oxygen evolution of Fe-Co(H₂PO₂)₂ at a current density of 10 mA·cm^-2 are 24 mV and 220 mV, respectively, and it can work stably for 40 h at 50 mA·cm^-2, showing excellent bifunctional electrocatalytic activity and good stability, and has broad application prospects in the field of water electrolysis and hydrogen production.

Ammonia energy catalytic combustion technology has become a hot topic in clean energy research due to its high thermal efficiency and low pollution characteristics. The core challenge lies in the development of efficient catalysts. However, traditional catalyst design predominantly relies on experience-driven trial-and-error methodologies, which are often plagued by extended development cycles and elevated costs. A machine learning (ML)-enabled approach aimed at the targeted development of catalysts has been introduced. By integrating both experimental data and literature findings, two comprehensive databases were constructed: one comprising 597 samples related to ammonia conversion rates and another containing 529 samples pertaining to nitrogen selectivity. Both databases encompass various catalyst compositions (e.g., Fe₂O₃, CuO, CeO₂) as well as reaction parameters (e.g., temperature, equivalent ratio). Three ensemble learning models,random forest regression (RFR), gradient boosting decision tree (GBDT), and categorical boosting (CatBoost),were employed to predict catalytic performance. The results demonstrated that the RFR model exhibited superior comprehensive performance in dual-target prediction. On the test set, the model achieved a coefficient of determination (R²) of 0.912 with a mean absolute error (MAE) of 0.047 for ammonia conversion rate prediction, while for nitrogen selectivity prediction, it attained an R² of 0.918 and MAE of 0.033, indicating enhanced accuracy with reduced prediction errors. Feature importance analysis revealed reaction temperature as the dominant factor influencing both ammonia conversion rate and nitrogen selectivity. Partial dependence plot (PDP) analysis uncovered significant synergistic effects between CuO and CeO₂ loadings. The model predicted nonlinear correlations between bimetallic loading ratios and catalytic performance at 500, 700, and 900℃. Experimental validation confirmed strong agreement between predicted and measured values, with prediction errors below 3%, achieving precise catalyst performance evaluation. This machine learning-driven paradigm revolutionizes traditional catalyst development approaches, reducing development cycles by over 60% and substantially lowering costs. The established transferable methodological framework provides critical insights for designing catalytic systems in clean energy applications, demonstrating significant engineering value through its generalizability and operational efficiency enhancement.

In recent years, rare earth element-modified titanium dioxide (TiO₂) has demonstrated remarkable potential in environmental catalysis. In this study, a series of rare earth element modified RE-B-TiO₂ (RE = Nd, Sm, Eu, Er, Tm) nanocatalysts were prepared by a solvothermal method, and their performance and mechanism of degradation of tetracycline hydrochloride (TCH) under visible light were systematically investigated. Among these catalysts, Er-B-TiO₂ exhibited the highest photocatalytic activity under visible light irradiation. Multiscale characterization techniques (XRD, TEM, XPS) revealed that Er-B-TiO₂ possesses a distinctive self-assembled nanorod architecture composed of bipyramidal nanocrystals with dual crystal-facet exposure. This unique configuration facilitates enhanced spatial separation efficiency of photogenerated charge carriers. Under visible light illumination, Er-B-TiO₂ achieved 93.2% TCH degradation efficiency within 120 min. Mechanistic studies demonstrated that Er³⁺ doping synergistically enhances catalytic performance through three critical pathways: (1) introducing abundant oxygen vacancy defects, (2) effectively suppressing electron-hole recombination, and (3) extending light absorption to the visible spectrum via 4f-orbital-mediated bandgap engineering. Environmental parameter analysis revealed significant regulatory effects of solution pH and specific anions (e.g., Cl^-, \mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}) on the degradation process. Radical trapping experiments combined with EPR spectroscopy identified superoxide radicals (·{\mathrm{O}}_{\mathrm{2}}^{-}) as the dominant reactive species. HPLC-MS analysis elucidated the TCH degradation pathway, while toxicity assessment confirmed substantial reduction in ecological toxicity of degradation intermediates. This work not only clarifies the intrinsic mechanism of rare earth elements in enhancing TiO₂ photocatalytic activity through band structure modulation, but also provides new insights for designing efficient and stable visible-light-responsive environmental catalysts.

Mixed matrix membranes combine the advantages of polymers with inorganic materials, which can outperform polymer membranes and have a wide range of applications in gas separation. To obtain high-performance CO₂/N₂ separation membranes, sulfonated CAU-1 (CAU-1@BS) was prepared by the ring-opening reaction of the epoxy group of prop-1-ene-1,3-sultone (BS) with the primary amine group of CAU-1. Then, CAU-1@BS was added to polyvinylamine (PVAm) to prepare a casting solution, which was coated on a hydrophilic modified polysulfone ultrafiltration membrane to obtain a mixed matrix composite membrane. The chemical structure and pore structure of CAU-1@BS were characterized by XPS, FTIR and BET, and the morphological structure of the membrane was characterized by SEM. Furthermore, the effects of preparation and test conditions of mixed matrix composite membranes on gas separation were investigated. The results showed that as-prepared mixed matrix composite membranes exhibited excellent separation performance with a CO₂ permeance of 505 GPU and a CO₂/N₂ selectivity of 67, when the content of CAU-1@BS was 7% (mass). Their values were improved by 70.6% and 71.8%, respectively, compared with those of pristine PVAm membranes (CO₂ permeance: 296 GPU; CO₂/N₂ selectivity: 39). On the one hand, this is due to the fact that the sulfonic acid groups introduced through the ring-opening reaction not only act as Lewis basic sites for acid-base interactions with CO₂, but also adsorb water molecules to enhance the facilitated transport of CO₂ in the membrane. On the other hand, the gas separation performance of the membrane was improved by the synergic effect of the amine groups and porous structure of CAU-1@BS. In addition, under the condition of using CO₂/N₂ mixed gas as feed gas, the prepared mixed matrix composite membrane maintained good stability for up to 360 h, and its average CO₂ permeance and CO₂/N₂ selectivity were 527 GPU and 70, respectively, which shows that the membrane has good application prospects.

The structure-activity relationship of extractants holds significant position in solvent extraction research. Notably, studies exploring the impact of the structure-activity relationship of synergists on extraction performance are even more scarce. In this study, two aromatic substituted phosphodiester co-extractants were synthesized, namely, phenyl di(2-ethylhexyloxy) phosphate (BPPO) and p-methylphenyl di(2-ethylhexyloxy) phosphate (BTPO). Utilizing octyl 2-hydroxybenzoate (OHB) as the main extractant, we constructed two mixed extraction systems. First, we investigated the effects of various factors on the extraction experiment. These factor included the composition of the organic phase, the alkalinity of the aqueous phase, the phase ratio, the lithium concentration in the aqueous phase, and the saturated loading of the organic phase. The results demonstrated that the extraction performance and phase separation effect of the methyl-substituted OHB/BTPO extraction system were remarkably superior to those of the unsubstituted OHB/BPPO system. Given the better extraction performance of the OHB/BTPO extraction system, we employed it for lithium extraction from the mother liquor after lithium precipitation. By implementing a three-stage countercurrent extraction process, the extraction rate of lithium (E_Li) could reach 94%. Subsequently we conducted an in-depth study of the extraction mechanism using ultraviolet, fluorescence, and infrared spectroscopy. The results indicated that a Keto-Enol transformation took placed in the configuration of OHB during the extraction process. When it is in the Keto configuration, it has a 308 nm ultraviolet absorption peak and no fluorescence emission; when it is in the Enol configuration, it has a 340 nm ultraviolet absorption peak and produces 410 nm blue fluorescence under 340 nm wavelength light excitation. Meanwhile, obvious changes occurred in the CO stretching vibration (ν_CO) and the skeletal vibration of the benzene ring (ν_Ph) in the infrared spectrum.

Direct air capture of CO₂ is a necessary component for global warming suppression, and developing efficient technologies for low-concentration CO₂ separation has become a focus of scientific research in recent years. In this study, fluorine-containing 1F-PUiO-66, a polymer-MOF composite, was used as a filler material and blended with the corresponding cPIM-1 polymer matrix to construct mixed matrix membranes with loading of up to 50%(mass) and high affinity for CO₂, achieving efficient separation of low-concentration CO₂. Specifically, the prepared 50%(mass) 1F-PUiO-66/cPIM-1 membrane exhibited a CO₂ permeability as high as 6428.3 Barrer under 1%(vol) low CO₂ concentration inlet condition, and the CO₂/N₂ selectivity increased to 69.13, which improved the performance values by 1167.3% and 81.2%, respectively, compared to cPIM-1 pure membranes, and substantially exceeded the 2019 Robeson upper bound. This study demonstrates the significant CO₂/N₂ separation potential of polymer-MOF composite materials under low CO₂ concentration inlet conditions, which is important for actual industrial gas separation.

The produced water of oil and gas fields is the waste water produced in the process of oil and gas exploitation, which contains high value-added mineral resources such as lithium and bromine. Currently, the extraction of dissolved lithium and bromine needs to be carried out in steps, which is inefficient and cumbersome. Therefore, the development of synchronous extraction technology is of great significance for the efficient, green and low-cost resource extraction and recovery of lithium and bromine. LiMn₂O₄ (LMO) and BiOBr (BOB) electrode active materials are prepared by high temperature solid phase and hydrothermal methods, respectively, and then the LMO/BOB electrode system is constructed. The operating voltage of synchronous adsorption without membrane and synchronous desorption with membrane are regulated, and the mass ratio of active materials between the two electrodes is optimized. Under the optimized conditions, the adsorption equilibrium is reached in 3 h, the adsorption capacity of Li⁺ is 24.13 mg/g, and the adsorption capacity of Br^- is 88.13 mg/g. The desorption reaches equilibrium within 3 h, and based on the unit mass LMO electrode, the two-electrode adsorption can obtain 2.70 mmol LiBr solution at one time. The research results provide a method and data reference for the synchronous extraction and recovery of lithium and bromine in the produced water of oil and gas fields.

The separation of bio-based 1,3-propanediol is the bottleneck in its industrialization. Conventional adsorption resins have low adsorption capacity, require large amounts of eluent, and consume high energy consumption for target product recovery. To overcome this problem, the advantage of the affinity between 1,3-propanediol and boric acid was utilized in this study by immobilizing phenylboronic acid onto porous chloromethyl polystyrene resin to prepare two functional affinity resins, i.e. PS-APBA and PS-CPBA. Physico-chemical characterization was first conducted to confirm the successful grafting of phenylboronic acid groups and the thermal stability of the resins. The effect of pH on adsorption capacities of two resins was then investigated to determine the maximum adsorption capacities of 226.4 mg/g and 192.6 mg/g at pH 13, respectively. Furthermore, the adsorption characteristics were explored by adsorption kinetics, isotherm, dynamic, and binary competitive adsorption experiments, respectively. The experimental results indicated that the adsorption process could be fitted by the pseudo-second-order kinetic model. The Langmuir model was used to fit adsorption isotherm and obtain the maximum adsorption capacities of 328.1 and 314.9 mg/g for the two resins, respectively. Dynamic adsorption experiments were fitted by Thomas model to calculate the theoretical maximum dynamic adsorption capacities of 202.4 mg/g and 196.3 mg/g, respectively. Binary competitive adsorption experiments demonstrated that the resins had good adsorption selectivity for 1,3-propanediol. Finally, two resins were applied for adsorption and separation of 1,3-propanediol in the concentrated fermentation broth, and exhibited higher adsorption capacities after five adsorption-desorption cycles with desorption rates of 1,3-propanediol exceeding 96%. The above research results provide a new technical proposal for the efficient separation of bio-based 1,3-propanediol.

To address issues of deep spatiotemporal coupling among multiple processes in steel production parks, extensive carbon emission accounting, and unclear emission reduction pathways, a carbon flow evolution model for the entire steel production process was constructed, and a carbon flow monitoring and tracking and carbon emission accounting method was proposed. Taking a steel park in Nanjing as the research object, an analysis was conducted on the carbon evolution pathways and CO₂ emission characteristics throughout the steel production process. The findings reveal that at the system level, carbon primarily originates from purchased coke, coking coal, and pulverized coal injection, and accounting for over 80% of the total carbon input. In terms of carbon flow, over 87% of the carbon is converted into direct CO₂ emissions, while only about 2% enters end products. Notably, pulverized coal injection has the highest CO₂ conversion rate at approximately 84%, whereas limestone has the lowest at only 43%. At the process level, the ironmaking process generates the largest amount of direct carbon emissions, followed by the self-generated power sector, with the steel rolling process producing the least. Within the coking process, the proportion of carbon converted into products is the highest, while the proportion emitted as CO₂ is the lowest. The converter gas recycling rate is the highest in the steelmaking process, and the proportion of carbon converted into CO₂ emissions is the highest in the steel rolling process. Based on the system's carbon evolution pathways and the carbon conversion mechanisms of each process, a new method for accounting product carbon emissions was proposed. Additionally, the correlation mechanism between energy losses from by-product gases (such as gas venting and inefficient gas-powered generation) and carbon emissions was clarified, along with a series of recommended emission reduction pathways.

This study is aimed at addressing the challenges posed by the intricate internal mechanisms of wastewater treatment and the difficulty in achieving effective real-time control of effluent quality through online monitoring. A hybrid prediction model for effluent quality is proposed, combining data decomposition with an improved dung beetle optimizer (DBO)-optimized TCN-BiGRU/BiLSTM architecture. The correlation analysis method is used to select the variables with strong correlation with the outflow index from the inflow variables as the auxiliary input features of the prediction model. The effluent quality time series were decomposed and simplified into several subsequences using variational mode decomposition (VMD). The sample entropy of each subsequence was calculated, and the subsequences were classified into high and low complexity levels based on this measure. Accordingly, two hybrid prediction models, TCN-BiLSTM and TCN-BiGRU, were constructed. An enhanced DBO algorithm incorporating Tent chaotic mapping and Cauchy mutation strategies was introduced to optimize the combined model. Comparative experimental results demonstrate that in predicting effluent total nitrogen (TN) and chemical oxygen demand (COD), the proposed model outperformed the CNN-LSTM, VMD-TCN-BiGRU, VMD-TCN-BiLSTM, and VMD-TCN-BiGRU/BiLSTM models. It achieved reductions in average RMSE and MAE ranging from 35.22% to 52.41% and 39.38% to 55.53%, respectively, and increased the average R² by 2.91% to 7.55%. The prediction accuracy of the model is significantly improved, and it performs well for nonlinear complexity problems in measured data, and has good engineering application value.

Hydrogen-induced blister fracture is a damage phenomenon that occurs inside the rubber during the rapid depressurization of high-pressure hydrogen. A finite element model is established to investigate hydrogen-induced blister fracture in nitrile butadiene rubber (NBR), a commonly used sealing material. The internal damage evolution mechanism of NBR is discussed under complex operational conditions considering both single and cyclic hydrogen exposure. In addition, the effects of various factors on hydrogen-induced blister fracture in NBR, including fillers, hydrogen permeation characteristics, test conditions, and cavity parameters are studied. The results show that the most likely time for blister fracture in NBR is at the end of single hydrogen exposure. Cyclic hydrogen exposure can amplify cavitation damage and increase the risk of blister fracture. The addition of fillers can improve NBR's resistance to hydrogen-induced blister fracture. The increase in hydrogen solubility and the decrease in hydrogen diffusion coefficient can enhance the possibility of blister fracture. Reducing the hydrogen pressure and the depressurization rate can lower the risk of blister fracture. A larger cavity radius, a smaller distance of two cavities, and a larger number of cavities can bring a greater risk of blister fracture.

To address the issue of overheating in the end faces of contact mechanical seals under high-speed conditions, a novel contact mechanical seal structure with herringbone grooves on the outer side of the rotating ring was proposed. A fluid-solid heat transfer numerical model was established based on computational fluid dynamics (CFD) to examine the distributions of the flow field, temperature field, pressure field, and velocity field within the seal ring and the seal cavity. The heat transfer characteristics of fluid flow in the herringbone groove region and the seal cavity were analyzed, revealing the convective heat transfer mechanism and cooling principles. The results demonstrate that the pressure differential flow induced by the herringbone groove structure significantly enhances the mixing effect between the fluid near the heat transfer surface and the fluid in the seal cavity. Additionally, it increases the turbulence intensity near the groove walls. This flow thins the hydrodynamic and thermal boundary layers near the outer wall, raises the local Nusselt number, and improves heat transfer efficiency. As rotational speed increases, the heat transfer performance of the herringbone-grooved mechanical seal also improves. The influence of herringbone groove angle, depth, number of grooves, and end-face distance on heat transfer was analyzed, with the number of grooves and end-face distance having the most significant impact. Compared with traditional mechanical seals, the end-to-end temperature rise of mechanical seals with herringbone grooves on the outer side was significantly reduced. At a speed of 10000 r/min, the temperature rise decreased by 38.8 K, a 22.1% reduction. This significant reduction in seal temperature rise provides a theoretical basis for the optimized design and engineering application of high-performance contact mechanical seals.

Antibiotics are widely used in the medical field to treat infectious diseases. However, their high polarity and low volatility physical and chemical properties lead to a large amount of drug residues in wastewater, which in turn triggers a cascade effect of environmental-ecological-health risks, making bacteria resistant and destroying aquatic ecosystems. Consequently, the efficient removal of antibiotic residues from wastewater has become a critical environmental priority. Photocatalytic and photo-Fenton technologies have emerged as promising approaches for degrading antibiotic contaminants. However, existing methodologies are constrained by suboptimal catalyst recovery and limited photoreactor energy utilization, which restrict scalability from laboratory research to industrial implementation. To address these limitations, a PVDF/LFTCO (LaFe_0.55Ti_0.2Co_0.25O₃) catalytic membrane was developed through an in-situ functional layer design. The membrane facilitates photocatalytic and Fenton-like activation for the degradation of tetracycline hydrochloride. Under the synergistically coupled mechanism of photocatalysis and Fenton-like oxidation, catalysts undergo photoexcitation to generate photogenerated electron-hole pairs, which facilitate the efficient activation of H₂O₂ through charge separation and transfer processes coupled with redox cycling, subsequently generating reactive oxygen species. Consequently, the PVDF/LFTCO catalytic membrane exhibits stable and efficient degradation of tetracycline hydrochloride with a removal efficiency of 87.78% in a continuous-flow system, maintaining this performance within 90 min. After photo-Fenton-like regeneration, the degradation rate of tetracycline hydrochloride by the PVDF/LFTCO catalytic membrane after five cycles of reuse remains at 73.50%, providing an innovative solution for the construction of efficient wastewater treatment membranes.

Pore structure is one of the important factors affecting pyrolytic devolatiles. This study systematically investigates the evolution and fractal characteristics of semicoke pores at different pyrolysis final temperatures (393—1073 K) using integrated N₂ adsorption and fractal dimension analysis. A particle-scale model was developed based on pore evolution patterns, incorporating tar secondary cracking, volatile diffusion in fractal pores, and predicting transient temperature distribution, volatile yields, and pore structure changes. The results show that slit-shaped mesopores dominate during semi-coke pyrolysis, with pore evolution driven by drying degassing, organic decomposition with pore shrinkage, and increased heterogeneity from micropores. Pore structure mainly influences volatile yields by modifying tar diffusion pathways, while showing negligible effects on light gas production. This work provides fundamental insights into pore-volatile interactions that are crucial for pyrolysis reactor design and process optimization.

The rapid growth of municipal solid waste incineration in China has led to a sharp increase in the production of air pollution control (APC) residues. Potential environmental risks such as heavy metal leaching and dioxin release restrict the resource utilization of fly ash. This paper investigates the impact of adding NaH₂PO₄ during the water washing process on the pollution characteristics of the products from washing and thermal treatment (600℃ and 700℃) of APC residues. The results show that the addition of sodium dihydrogen phosphate reduces the leaching of Cl, Pb, Ba, and Se, but promotes the leaching of As and Cr during the APC residues washing process. When the addition of NaH₂PO₄ is no less than 5.0%, the leaching concentration of Pb in washed fly ash meets the limit values listed in Technical Specification for Pollution Control of Fly-ash from Municipal Solid Waste Incineration (HJ 1134—2020). Pb is the most abundant heavy metal in the wash liquor. Adding 5.0% sodium dihydrogen phosphate can reduce the Pb concentration in the wash liquor to below 10 mg/L. The washing-thermal treatment process promotes the volatilization of elements such as Pb, Cu, and Cd in APC residues, but the heavy metal leaching concentration of thermal-treated washed APC residues is low, meeting the corresponding standard limits. The temperature is identified as an important factor affecting the volatilization of heavy metals in washed APC residues, and less volatilization was observed under 600℃. After thermal treatment under 700℃, the content of Pb in washed fly ash is reduced from (1700±100) mg/kg to (320±80) mg/kg. The addition of NaH₂PO₄ inhibits the volatilization of chlorides and sulfates, but has no significant effect on the change of leaching characteristics of washed APC residues during thermal treatment. The research results provide scientific basis for the in-situ treatment of washed APC residues in the incinerator, which is beneficial for the source reduction, harmlessness, and utilization of APC residues.

The indirect internal reforming solid oxide fuel cell (IIR-SOFC) is equipped with a reforming porous medium layer adjacent to the cell, utilizing the heat generated by the cell to reform the fuel gas and provide hydrogen for the cell. However, the reforming reaction affects the temperature distribution within the cell, making it uneven, which in turn affects the cell's power generation performance and lifespan. In this paper, the numerical simulation method was used to obtain the effects of fuel and air flow directions, operating temperature, and reforming gas flow rate on the temperature distribution and power generation characteristics of planar indirect internal reforming SOFC. A gradient distribution of catalyst loading in the reforming channel was used to improve the temperature distribution. The results show that the maximum temperature difference in the cell is smaller when the gas in the anode and cathode channels flows in the same direction than when it flows in the opposite direction. As the operating temperature increases, the maximum temperature difference inside the cell gradually increases. As the flow rate of the reforming mixed gas at the inlet increases, the temperature gradient and power density first increase and then decrease. After changing the distribution of catalyst loading in the reforming channel, the temperature distribution in the battery tends to be uniform, the temperature gradient is significantly reduced, and the maximum temperature difference is reduced by about 60%.

During the development of combustible ice, timely decomposition and removal of hydrates in the drainage and production system is an important task to ensure flow safety during offshore combustible ice development. To address the unclear mechanisms of synergistic effects between free guest molecules and nanobubble formation in the liquid phase on CO₂-CH₄ hydrate decomposition kinetics, this study employed molecular dynamics simulations to construct a CO₂-CH₄ hydrate system with a 1∶1 guest molecule ratio and 100% cage occupancy. Under varying temperature conditions, controlled quantities of CO₂ or CH₄ molecules were introduced into the liquid phase to simulate and analyze the effects of mole fraction variations and nanobubble formation on hydrate decomposition rates. The results demonstrate that elevated concentrations of free guest molecules in the liquid phase accelerate CO₂-CH₄ hydrate decomposition. In particular, free guest molecules form larger-scale bubbles that dramatically enhance decomposition kinetics.

To investigate the impact of the porous media structural characteristics on combustion enhancement, a new structural parameter tortuosity was introduced on the basis of porosity and pore size to characterize the structural properties of porous media, porosity and pore size. Experimental studies were conducted to explore the combustion stability of low calorific value H₂/CO mixture within porous media under varying structural parameter conditions. The results show that porous media can improve the upper limit of stable combustion, broaden the lean combustion limit and reduce pollutant emissions. In contrast to the non-monotonic influence exhibited by porosity and pore size on combustion stability, the effect of tortuosity on combustion stability in the experiment shows a monotonic change trend, and the high tortuosity structure has a stronger combustion enhancement effect. By optimizing the structural parameters, the flame stability in porous media can be significantly improved. Additionally, the three structural parameters exhibit different impacts depending on the combustion states. In scenarios involving high power density combustion, a structure with high porosity contributes to the reduction of CO emissions, whereas for ultra-lean combustion, a structure with high tortuosity and low porosity is recommended.

Nanofluids have become a research focus in the field of solar thermal applications due to their excellent photothermal conversion performance. In this paper, a two-step method was used to prepare water-based carbon black nanofluids with mass fractions in the range of 0.001%—0.02%, and their stability was characterized. The photothermal conversion performance of water-based carbon black nanofluids with different mass fractions was tested under simulated sunlight and natural light irradiation. It was found that within a certain range, with the increase of carbon black mass fraction, the photothermal conversion efficiency of the nanofluid was significantly improved. The photothermal conversion efficiency of 0.009% nanofluid under natural light can reach 60.31%, reflecting excellent photothermal conversion performance. This study confirmed that water-based carbon black nanofluid was an excellent solar photothermal conversion medium, which can achieve efficient solar photothermal conversion.

As a good cold storage medium, salt solution ice slurry is widely used in air conditioning, refrigeration, biomedicine and other fields. In this study, the flow field and phase field method (PFM) were coupled, and lattice Boltzmann method (LBM) method was used to analyze the dendrite growth and distribution characteristics of the supercooled salt solution under static and flowing conditions. Meanwhile, partial least squares (PLS) were used to analyze the weight of influencing factors on the supercooled crystallization of the solution. The results show that when the flow velocity increases from 0.1 m/s to 0.5 m/s, the dendritic growth rate upstream increases by 27%, while that of downstream increases by 12%. The influence of anisotropy intensity on dendrite shape is weakened by flow velocity. The dendrite growth rate decreased with the increase of concentration. Supercooling degree and heat flux are important parameters affecting ice crystal growth. With the increase of supercooling degree and heat flux, supercooling crystallization of salt solution is more likely to occur, and dendrite growth is more obvious. It provides scientific guidance and reference for mastering the crystallization solidification characteristics and freezing state regulation of salt solution.

Hydrogen fuel cell vehicles require a refueling pressure of 70 MPa, which necessitates that liquid hydrogen refueling stations incorporate both pressurization and vaporization processes. The demands of such refueling put significant pressure on liquid hydrogen pumps. This study proposes a pump-thermal synergistic pressurization system aimed at localizing core equipment. The system combines a 45 MPa liquid hydrogen pump with thermal compression to lower the pump's outlet pressure, thereby enhancing the system's feasibility and compatibility with domestic pumps. Based on the pump-heat synergistic pressurization liquid hydrogen refueling station system, a thermodynamic and exergy analysis model was constructed. Through the study of core components, refueling process and the whole system, the exergy loss and exergy efficiency of components such as liquid hydrogen pump, pressure vessel, heat exchanger and pressure control valve under different working conditions were analyzed. It has been observed that as the outlet temperature and pressure increase, the exergy efficiency of the liquid hydrogen pump decreases. Moreover, the 45 MPa liquid hydrogen pump exhibits a higher exergy efficiency compared to the 90 MPa pump. During the pump-thermal pressurization, the initial temperature and pressure significantly affect the exergy efficiency of the pressure vessel. By optimizing the component parameters, the exergy efficiency of all system components can be maintained above 0.74. This study highlights the importance of energy utilization in the novel liquid hydrogen refueling station system through exergy analysis, providing a foundation for further system optimization and performance enhancement.

To systematically enhance the charging and discharging performance of a shell-and-tube phase change thermal energy storage exchangers, this study utilized a horizontal shell-and-tube experimental platform with a movable inner tube, combined with a high-precision image acquisition system and a quantitative solid-liquid interface characterization method. We investigated the effects of different inner-tube vertical translation speeds (0.01 mm·s^-1, 0.05 mm·s^-1, and 0.1 mm·s^-1) and translation distances (5 mm, 10 mm, and 20 mm) on charging and discharging characteristics. The results demonstrate that inner-tube motion can effectively intensify the heat-transfer process of the phase-change material, with charging/discharging performance improving as the translation speed and distance increase. Compared to the static state, the optimized inner tube movement strategy reduces the heat storage and release times by 5221 s and 1978 s, respectively, and the average temperature change rate increases to 1.82 times and 1.07 times that of the static state, respectively. These findings provide guidance for the optimal design of movable-tube phase change thermal energy storage devices and lay the groundwork for active heat-transfer enhancement technologies.

The triply periodic minimal surface (TPMS) structure provides a new solution for the design of phase change thermal storage system due to its unique geometric morphology, adjustable pore structure and excellent thermal performance. In this paper, four typical TPMS structures, including Gyroid-Sheet, Gyroid-Network, Diamond-Sheet, and Diamond-Network, were fabricated using selective laser melting technology, and were composited with paraffin. Based on a visualized experiment under a side-heating boundary condition, the influence of porosity, unit cell structure and types on the effective thermal conductivity, specific surface area, and thermal storage performance of the paraffin/TPMS porous AlSi10Mg alloy composite phase change materials (PCMs) were investigated. The solid-liquid interface evolution and temperature distribution during the melting process were determined, and the thermal energy storage enhancement mechanism of TPMS structures was revealed. The results indicate that TPMS-structured composite PCMs exhibit significant advantages in enhancing thermal storage performance, characterized by high effective thermal conductivity and large specific surface area. The thermal storage rate was improved by more than 60% compared to pure paraffin. Among the four TPMS structures, the Diamond-Sheet structure demonstrated the fastest thermal energy storage rate and the best temperature uniformity, when the porosity ranged from 70% to 85%. The purpose of this study is to provide guidance for the structural design of porous metal composite phase change materials with TPMS structures and to offer experimental data support for their applications.

Reducing energy consumption in building operations requires energy-efficient management of HVAC fresh air systems. Implementing low-carbon strategies in ventilation systems is critical for sustainable development. The membrane fresh air total heat recovery device has a wide range of application potential in the field of energy saving of fresh air system due to its compact structure and high heat and moisture exchange efficiency. Polyvinylidene fluoride(PVDF) membranes were modified with graphene oxide (GO) and polyvinylpyrrolidone (PVP) to enhance heat-moisture transfer performance. The water vapor transmission rate (WVTR) was rigorously measured, and the effects of membrane composition, surface hydrophilicity, and pore microstructure on moisture permeation mechanisms were systematically analyzed. Experimental evaluations were conducted on heat recovery cores fabricated from the modified PVDF membranes within a fresh air system. The impacts of temperature, relative humidity, and airflow rate on total heat recovery efficiency (THRE) were investigated. A predictive model for THRE was subsequently developed using dimensionless parameters. The results indicate that with 0.1 g GO and 7.0 g PVP additives, the modified PVDF membrane exhibited a contact angle of 39°, achieving a water vapor transmission rate of 3641 g/(m²·d). Compared to commercial membranes, the modified PVDF membranes exhibited 29.7% higher THRE and 33.7% greater total heat recovery capacity (THRC). The dimensionless predictive model demonstrated high accuracy, with deviations from experimental data consistently below ±5%.

Ultra-low temperature liquid storage technology faces technical bottlenecks of high heat leakage of passive insulation scheme and high energy consumption of active insulation scheme. This paper proposes a thermal transfer model that couples actively cooled thermal shield (ACTS) insulation with multi-layer insulation (MLI) to minimize both heat leakage and cooling power consumption in cryogenic vessels. An experimental setup for evaluating the ACTS insulation performance was established based on a liquid helium vessel, and the transient temperature variation and heat transfer behavior of MLI and ACTS were analyzed to validate the accuracy of the theoretical model. Through parameter optimization studies, the effects of ACTS temperature, position, and quantity on the MLI temperature gradient field, heat flux distribution, and cooling power consumption were revealed. The results show that ACTS controls the temperature gradient, extending the cryogenic region of MLI and reducing the temperature difference between the cryogenic vessel and ACTS. The optimal temperature and position for a single ACTS insulation are 73.6 K and 0.425, respectively, with a high-temperature threshold of 150 K. For a dual ACTS insulation system, the optimal positions are 0.2375 and 0.5875, with temperatures of 36.4 K and 128.7 K, leading to a 24.6% reduction in the comprehensive evaluation factor compared to the single ACTS insulation. The three ACTS insulation systems reduce the heat flux density of the cryogenic vessel to 0.0202 W/m², which is 44.6% and 28.5% lower than the single and dual ACTS insulation systems, respectively, verifying the significant advantages of multiple ACTS in improving the insulation performance of cryogenic vessels. This study provides theoretical and data support for optimizing the active thermal insulation performance of cryogenic vessels.

In this work, a hydrothermal approach is employed to synthesize γ-Al₂O₃ nanoparticles with an average size of 40 nm which are used as tribocatalyst for Rhodamine B (RhB) dye degradation under the driving of polytetrafluoroethylene (PTFE) stirring disk. The tribocatalytic RhB dye degradation ratio of the synthesized γ-Al₂O₃ nanoparticles is comprehensively characterized and analyzed under the controlled stirring speeds, different dye solution's concentrations and pH conditions. The evaluation on the recyclability of γ-Al₂O₃ nanoparticles has also been done through monitoring the change of RhB dye degradation performance after reusing the catalyst for multiple cycles. The maximum dye degradation ratio of 95% for a 10 mg/L RhB solution is achieved for 3 h tribocatalysis reaction time under the optimization conditions of 600 r/min mechanical stirring speed and the pH of 7. The RhB dye degradation ratio can still keep >90% after recycling \mathrm{\gamma }-\mathrm{A}{\mathrm{l}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}} nanoparticles for five cycles. γ-\mathrm{A}\mathrm{l}₂\mathrm{O}₃ nanoparticles exhibited efficient dye degradation performance and good recycling stability, indicating that they have important application prospects in the tribocatalytic degradation of dye wastewater driven by friction mechanical energy in the collection environment.

Although methyl acrylate (MA) and methyl methacrylate (MMA) share similar monomer structures, they exhibit significant behavioral differences in reversible addition-fragmentation chain transfer (RAFT) polymerization. This study focuses on investigating the intrinsic mechanisms underlying the differences in molecular weight control and dispersity between MA and MMA by comparing four distinct chain transfer agents (CTAs). Combining polymerization kinetics experiments with density functional theory (DFT) calculations, the fragmentation tendency (φ) of intermediate radicals and the interaction strength between CTAs and propagating radicals (control index, C) were analyzed. The results show that the dissociation tendency of the intermediate free radical and its interaction strength with CTA are key factors affecting the polymerization rate and molecular weight distribution. When φ approaches 1 (e.g., in MA/CTA 2-4 systems), the molecular weight aligns well with theoretical predictions. In contrast, for MMA systems, the stabilization of P_n· radicals by the methyl group hinders R· dissociation (φ approaches 0), leading to significant deviations from theoretical molecular weights in the early stages, which are gradually reduced through short-chain regeneration. This study provides experimental and theoretical insights into the anomalous molecular weight prediction behavior in RAFT polymerization, offering valuable guidance for the precise control of RAFT systems.

Biomass-derived carbon quantum dots (CDs) have excellent biocompatibility and renewable properties. The current synthesis methods have the disadvantages of cumbersome steps and low economic efficiency, which is not conducive to the large-scale production of CDs. Herein, using Narcissus bulbs as biomass precursor materials, Narcissus-based carbon dots (Nar-CDs) were synthesized quickly and easily through a high-temperature carbonization and ultrasonic dispersion-separation process. The yield can reach up to 16.4%. The successful synthesis of Nar-CDs was confirmed through various characterization techniques, including UV-visible spectroscopy, fluorescence spectroscopy, TEM, XRD and FTIR. Nar-CDs exhibited bright blue fluorescence when excited at a wavelength of 365 nm. Analysis revealed that the surface of Nar-CDs contained abundant oxygen-functional groups, providing excellent water solubility. The antioxidant properties of Nar-CDs were assessed using KMnO₄ and DPPH methods, showing strong reducing and free radical scavenging abilities. Nar-CDs also exhibited good biocompatibility, almost no toxicity to HUVEC cells, and no obvious hemolysis effect. The above results demonstrate their potential application value.

It is of great significance to prepare low-temperature curable high-performance benzoxazine resins from biomass raw materials, which can meet the requirements of sustainable development in the industrial field. In this paper, 4-hydroxybenzonitrile and vanillonitrile were synthesized from vanillin and p-hydroxybenzaldehyde. Two new biobased benzoxazine monomers, HN-fa and VN-fa, were synthesized by solvent-free method, and then cured to prepare poly(HN-fa) and poly(VN-fa). The effect of nitrile group on reducing ring-opening polymerization of benzoxazines were studied by DSC. Due to the existence of nitrile functionality, the peak curing temperatures of HN-fa and VN-fa were as low as 200 and 206℃, respectively. In addition, the heat resistance of poly(HN-fa) and poly(VN-fa) was investigated by TGA and MCC. Poly(HN-fa) and poly(VN-fa) exhibited high glass transition temperatures (T_g) of 247 and 189℃, respectively. Moreover, these two thermosets also showed excellent flame retardant properties. These attractive results demonstrate that the newly designed nitrile-containing biobased benzoxazine monomers can be used for preparing high heat resistance and low temperature processed materials.

In order to improve the suppression effect of ultrafine water mist on the explosion of lithium battery pyrolysis gas (LBPG) and reduce the potential corrosion and environmental risks of conventional ultrafine water mist suppressants, the bio-based surfactant CAB35 and antioxidant OPC were selected as additives for ultra-fine water mist. The experiments were conducted on the suppression of LBPG explosion by the no ultra-fine water mist, the pure ultra-fine water mist, the monetary system ultra-fine water mist with CAB35 or OPC, and the binary system ultra-fine water mist with CAB35@OPC based on the LBPG explosion propagation and suppression experimental system. By analyzing the suppression characteristics of ultrafine water mist of different fog fluxes, different concentrations of mono-system and binary systems on LBPG explosion overpressure and its peak value, explosion flame shape, explosion flame speed and other parameters, it was found that the explosion flame under different working conditions showed Searby characteristic flame. The monetary system ultra-fine water mist with CAB35 or OPC had certain suppression effects on LBPG explosion and were superior to the pure ultra-fine water mist. Within the experimental range, the enhancement trend of the suppression effect of the monetary system ultra-fine water mist gradually slowed down with the increase of mist flux. The optimal suppression concentrations of CAB35 and OPC were 0.5%(mass) and 1.0%(mass), respectively. But in contrast, the binary system ultra-fine water mist with 0.5%CAB35@1.0%OPC had a better suppression effect than the monetary system. With the increase of the fog flux, the suppression effect becomes significantly stronger, the flame deformation is more obvious, and the buoyant flame appears earlier. When the fog flux is 12.6 ml, the explosion overpressure peak value under the action of ultrafine water mist is 14.3 kPa, which decreases by 60.3% compared to the case without thewater fog and the arrival time of the overpressure peak value is delayed by 11.8 ms, and the average flame speed and peak speed are 10.2 m/s and 20.7 m/s respectively, which decreases by 71.8% and 68.4% compared to the pure water fog. Based on the theory of fire and explosion prevention, the synergistic suppression mechanisms of the binary system ultra-fine water mist with CAB35@OPC are clarified. The research results can provide technical support for the development of green and efficient LBPG explosion suppression strategies.

Accurate localization of natural gas pipeline leakage points is of great significance for emergency response to accidents. In view of the defects of existing leakage location methods that rely on instantaneous signals, they are easily disturbed by pipeline operation noise, and have insufficient positioning accuracy, a pipeline leakage location method based on TPE (tree-structured Parzen estimator)-XGBoost (eXtreme gradient boosting) model is proposed. This method utilizes pressure drop rate data collected at 5-second intervals after leakage to train and predict the model. The hyperparameter optimization performance of TPE is compared with PSO (particle swarm optimization), BOA (Bayesian optimization algorithm), and Optuna methods, addressing the challenge of hyperparameter search in the model. Additionally, the prediction accuracies of the TPE-XGBoost model are compared with those of SVM (support vector machine), CNN (convolutional neural network), and CNN-LSTM-Attention models. The effects of dataset time series length and superimposed running noise on localization accuracy are also analyzed. The results demonstrate that the TPE optimization algorithm enhances the accuracy of the XGBoost model, outperforming PSO, BOA, and Optuna in hyperparameter optimization. Compared to other localization models, the TPE-XGBoost model achieves the highest prediction accuracy, with an R² value of 0.9835 and a localization error of only 3.77% on the test set. In contrast, the R² values for SVM, CNN, and CNN-LSTM-Attention models are 0.3684, 0.9285, and 0.9821, respectively. Analysis of the impact of time series length reveals that, within the data length range of 30 to 150 seconds, model decision coefficients increase with longer time series, and significant differences in model hyperparameters across time lengths are observed. When the experimental group with pipeline running noise is introduced, all models' accuracy decreases, while the model configuration adapts by adjusting hyperparameters to extract valid information through increased segmentation. In this noise-added experimental group, the R² of the XGBoost model is 0.9580 and the localization error is 7.58%.

The Shenhua's direct coal liquefaction (DCL) technology has advanced from the first generation (1G) to the second generation (2G). This progress has overcome many engineering challenges encountered in the 1G technology, but scarcely addressed the environmental changes of coal from 1G to 2G that influence the kinetics of coal conversion, particularly with regard to the oil yield. This study examines the temperature distribution of coal in the liquefaction reactors, the changes in concentrations of coal and hydrogen donor solvent due to the alteration in the solvent recycle strategy, from internal recycle in the 1G to external recycle in the 2G, and as a result, the changes in radical reactions and oil yield. It shows that the reaction time as well as the concentrations of coal and hydrogen donor solvent in the 2G technology is lower than those in the 1G technology. These changes may lead to lower coal conversion and oil yield in 2G technology compared to the 1G technology.Reduce the amount or temperature of the external circulating solvent to improve oil yield, reduce condensation reactions, and enhance plant stability.