Hexagonal aluminum nitride (h-AlN) is a kind of new Ⅲ-Ⅴ two-dimensional material. It has similar molecular structure and material properties with graphene and has been extensively focused. However, its thermal conductivity property has not been fully studied. In this paper, the thermal stability and thermal conductivity of single-layer h-AlN films at different temperatures have been studied, and its phonon dispersion also has been analyzed by using molecular dynamics simulation. The results show that single-layer h-AlN materials maintain structural stability at very high temperature (3500 K), and the thermal conductivity can reach 264.2 W·m^-1·K^-1 at room temperature. As result of phonon scattering, the thermal conductivity of the material is significantly reduced at temperatures above 500 K. These findings will provide theoretical guidance for the control of heat conducting of h-AlN materials and the application of high-temperature heat-conducting materials.

In observation of accurately determining the pore size distribution (PSD) of activated carbons by employing the non-local density functional theory (NLDFT), the effect of surface roughness resulted from the distribution of carbon atoms on the accuracy was evaluated in terms of comparison of the adsorption equilibrium of argon. The classical NLDFT, which was developed based on the approximation to the smooth distribution of the density near the surface, was modified by taking into account the influence from the uneven distribution of the carbon atoms on the surface. The accuracies of the results from the modified model were firstly evaluated by the adsorption data of argon on adsorbent surfaces which respectively have even and uneven distribution of carbon atoms. Experimental data of argon adsorption on the activated carbon at 87.3 K was then taken as a reference, and comparisons were accordingly made between the adsorption isotherms calculated by the classical and modified NLDFT. The PSD, which covers the range of 0.35-12 nm, was finally determined by employing optimization function. Results show that the modified model can bring about the continuous distribution of PSD, and the relative error between the results determined by calculation via the PSD and those from experiment can be less than 10%. However, the calculation from the classical model has an interrupt at a pore width about 1nm, and the resulted maximum relative error amounts to 45%. It suggests that the modified model can more accurately calculate the PSD of the activated carbon having uneven distribution of carbon atoms around the surface.

In this paper, aiming at ternary salt-water systems of Na⁺//Cl^-,NO₃^--H₂O, Na⁺//Cl^-,SO₄^2--H₂O and Na⁺,K⁺//Cl^--H₂O, the freezing points, eutectic points and the crystallization regularities of salts were investigated; the three-dimensional phase diagrams of temperature-composition of the ternary systems were plotted according to experimental data. The results were as following:the relationships among the freezing point, eutectic point, phases and the compositions of solution for the ternary system can be expressed by triangular prism. In the three ternary systems, there were no double salts at the eutectic point temperature, and there was an eutectic point with two salts and ice, three eutectic lines with single salt and ice or two salts, a crystallization zone with ice and two single salt. The three-dimensional phase diagram of temperature-composition of solution can be used to describe the relationships among the crystalline regions, freezing points or eutectic points and the compositions of liquids for the ternary salt-water systems visually, and to determine the precipitation processes of salts or ice as cooling solution. Three empirical formulas about freezing points were established. The empirical formulas of freezing point and the excess Gibbs free energy model were used to predict the freezing point and eutectic point of the ternary systems, which turned out that the calculated values were in good agreement with the experimental values.

The stable phase equilibria of the quaternary system Li⁺, K⁺, Mg²⁺//B₄O₇^2--H₂O at 273 K were studied using isothermal solubility equilibrium method. The solubility of the salts and densities in the system were determined, respectively. According to the experimental data and the corresponding equilibrium solid phase, the isothermal solubility diagram, water content diagram about the system Li⁺, K⁺, Mg²⁺//B₄O₇^2--H₂O at 273 K and the corresponding density composition diagram were plotted, respectively. Experimental results show that there are no complex salt or solid solution, and the system belongs to a simple eutectic type. The phase diagram is constituted by an invariant point, three univariant solubility curves and three solid phase crystalline regions. The three solid phases crystalline regions correspond to Li₂B₄O₇·3H₂O, K₂B₄O₇·4H₂O and MgB₄O₇·9H₂O. In addition, the density of saturated solution reached maximum at invariant point. Finally, a comparative analysis and discussion have been made in this paper for the stable phase diagrams of the system at 273 K, 288 K, and 348 K.

A industrial-scale experimental pipeline with the total length of 258 m and inner diameter of 233 mm was developed to study the thermodynamic properties of pipeline discharge of CO₂. Three groups of release experiments with pipeline filled with supercritical CO₂ were conducted with three different orifices with diameters of 15 mm, 50 mm and full bore individually. Thermocouples were installed on the wall of pipeline to monitor the temperature distributions of the medium inside the pipeline. The characteristics of the phase and density changes and heat transfer processes were studied. Experimental results showed that the pressure and temperature of fluid and the temperature of wall decreased, and eventually became stable in the discharge process. The phase of CO₂ was changed from supercritical state to gas-liquid two-phase and finally to gas phase during discharge. It was also obtained that the drop range of temperature was the largest and the intensity of convection heat transfer was the strongest during the initial stage. And the temperature of inner surface of the pipeline decreased more severe and the intensity of convection heat transfer was weaker with the increasing distance from the discharge port. Both the time of discharge and of heat transfer between medium and pipeline became shorter as the orifice diameter decreased. In addition, the temperature gradient between the fluid and the pipe and the intensity of convection heat transfer increased along the direction of pipeline.

Floating LNG production storage and offloading unit (FLNG, also known as LNG-FPSO) is a kind of floating production device for offshore gas field development. The natural gas liquefaction process is a core technology of FLNG, which has a huge impact on the safety, stability and costs of the equipment. Because of the special conditions of offshore operations, FLNG liquefaction process is required not only to achieve the most basic functions of liquefaction, it is also expected to overcome the interference of various constraints. In order to research the performance of the coil wound heat exchanger under sloshing conditions at sea, an experimental device of dual mixed refrigerant liquefaction processes is established and the sloshing experiment of coil wound heat exchanger is carried. The results show that:when the experimental device is under sloshing conditions, pressure reduces before throttle valve and increases after the throttle valve, the performance of throttle valve and coil wound heat exchanger becomes worse.

In order to study multi-phase distribution characteristics of slender particles in scrubbing-cooling chamber, an improved direct sampling method was used to simultaneously measure locally axial and radial distribution of solid concentration and gas holdup in a cold model apparatus at various operating conditions. The cold model apparatus was scaled down according to geometric dimensions of scrubbing-cooling chamber of industrial gasification system. The results showed that scrubbing-cooling chamber could be divided into two zones of the upper gas-liquid-solid mixing zone and the lower solid-liquid flowing zone with boundary at cross-section of the downcomer outlet. The gas-liquid-solid mixing zone was consisted of downcomer outlet, bubble-break plate and gas cap regions, while the solid-liquid flow zone was consisted of gas phase turbulence, recirculation, and secondary flow regions. Due to compounded effects of particle hindrance (slowed down sedimentation) and agglomeration (accelerated sedimentation), the axial distribution of solid concentration exhibited wavy fluctuations. The increase of annular gas velocity, solid volume concentration and aspect ratio of length over diameter enhanced bed turbulence and promoted radial gas dissipation. Change of operating conditions altered particle drifting velocity and resulted in fluctuation of radial solid concentration distribution. Under the effects of gas turbulence and recirculation, the secondary flow region showed circular flow where the “wall effect” of fluids and particles forced solid concentration higher at center but lower near wall.

To investigate the evaporation characteristics of porous media with different porosity, 2 pressed slice samples composed of nickel powder are manufactured with porosities 0.85, 0.75 and 0.60 (named sample A,B and C). The slice samples are long and thin that the wetting frontier movement can be clearly visible during suction. The samples were firstly used in suction experiments in which ethanol penetration was recorded by a high-speed camera. The results show that the sample with larger porosity has higher suction rate. It is because that porous media with larger porosity have larger pore sizes, which can promote the suction rate according to theoretical analysis. Next the samples were heated with constant heat load to test their cooling ability and research their heat transfer efficiency by evaporation. Heating experiments were separated into 3 parts:steady state-cooling, dry-cooling and wet-cooling. Steady state-cooling results show that larger porosity sample has higher evaporation rate mainly due to its higher suction ability. Dry-cooling is aimed to compare samples' transient cooling ability. The results indicate that the highest heat flux caused by evaporation belongs to sample A while its cooling time is the shortest. Although sample C keeps cooling for the longest, its limited evaporation heat flux constrains its cooling degree. Sample B, with both modest evaporation heat flux and cooling time decreases the heater temperature most. In wet-cooling test (on purpose of testing samples' performance in dry-out condition), sample A keeps itself wet for the longest time and has the highest dry-out temperature, representing the best ability to avoid dry-out phenomenon. Sample B shows relative low superheat degree and the longest time in intensive evaporation, resulting in its overall working temperature being the lowest.

Steam turbines are critical power generation equipment in electric power industry. Understanding water vapor condensation flow is important to improve efficiency and safety of steam turbines. Due to complexity of high speed condensation flow in steam turbines, no universally accepted nucleation model is available at present and current numerical models usually neglect vapor-liquid slip. Considered steep distribution and change sensitivity of condensing parameters, a double fluid numerical model of shear stress transport (SST) k-ω-k_d two-phase turbulence, which can not only describe transonic flow of compressible gas accurately but also capture parameter jump instantly, was used to analyze condensation flow characteristics in turbine rotor blade tip section. The study revealed influence of pressure ratio on non-equilibrium condensation flow characteristics of wet steams and summarized changing patterns of surface pressure, nucleation rate, humidity, and number of water droplets. Results showed that calculation of pressure ratio at compression surface was in good agreement with experimental data under various operating conditions, although some error was observed in the second half of suction surface. The two fluid numerical model was applicable to both overheating operation and condensations with slight overcooling inlet. But pressure jump caused by condensation shock could hardly be caught for large overcooling inlet. Shock wave interference and vortex mixing had a great influence on distribution of water droplets.

A binomial distribution function suitable for geometric grid was proposed and applied in population balance model (PBM) to simulate the particle size distribution (PSD) of activated sludge after flocculation. The results showed that the PSD and mean size simulated by using binomial distribution give better agreement with the experimental data than those simulated by using binary distribution. The accuracy of simulation of PSD and mean size can be improved by calibrating the value of parameter C_p of binomial distribution function. Different from other daughter particle distribution which can only describe one-type daughter particle distribution, the binomial distribution function shows a strong adaptability and can present more probable daughter particle distributions through adjusting the parameter C_p. Moreover, the value of parameter C_p might also characterize breakage behavior of particle:a smaller C_p value might imply that the particle display strong stability leading to large numbers of large daughter particle, whereas a larger C_p value might imply that the particle display weak stability and the large-scale fragmentation resulting in large numbers of small daughter particle.

The thermal conductivity of CO₂ hydrate was measured in this study. The effects of three kinds of nanoparticles, including Al₂O₃, Cu, and SiO₂, with different mass fractions (0.05%, 0.1%, and 0.15%) and different nanoparticle dimensions (10, 30, and 50 nm) on CO₂ hydrate thermal conductivity were investigated. The results show that CO₂ hydrate thermal conductivity increases with the increase of temperature, ranging from 0.553 to 0.5861 W·m^-1·K^-1 at -5-5℃. And the additive of dispersant SDBS has positive influence on thermal conductivity of CO₂ hydrate-nanoparticle system. With the same mass fraction and particle size, Cu nanoparticles show better effect to enhance CO₂ hydrate thermal conductivity than Al₂O₃ and SiO₂ nanoparticles. But considering the formation of CO₂ hydrate and the suspension stability of solution, Al₂O₃ is more suitable to be used as the promoter of thermal conductivity. The thermal conductivity of CO₂ hydrate increases with the decrease of particle size of the Al₂O₃ nanoparticles. The increase rate of thermal conductivity in 15 nm hydrate-nanoparticle system is 12.7% higher than that in 50 nm hydrate-nanoparticle system. In addition, the increase of CO₂ hydrate thermal conductivity is improved from 4.2% to 8.2% when the mass fraction of Al₂O₃ nanoparticles increases from 0.05% to 0.15%.

The numerical method is employed to investigate the influence of contaminated degree of bubble surface on its wakes for the spherical bubble under moderate Reynolds number (25 ≤ Re ≤ 500). By referencing the flow past a sphere and the stagnant cap model, one kind of three-dimensional model for contaminated spherical bubble under moderate Reynolds number is proposed. The interface contaminated degree is dependent on the magnitude of the cap angle. The larger the cap angel is, the slighter the bubble interface pollution is. The present results show that, for 25 ≤ Re ≤ 200, the magnitudes of the vortex length, the vortex center position distance to the bubble rear and the separation angle decrease with the decrease of the bubble surface contaminated degree but the distribution trends of those parameters against the Reynolds number are similar; for 250 ≤ Re ≤ 500, the decrease of the bubble surface contaminated degree weakens the three-dimensional property of vortexes, reduces the strength of orderly shedding vortexes until the shedding phenomenon disappears at Re=350, and reduces the disorder of shedding vortexes until the shedding phenomenon disappears too at Re=500.

The boiling heat transfer characteristics of R290 in smooth horizontal copper tubes with inner diameters of 4,6 mm was investigated experimentally. The effects of mass flux, heat flux, saturated temperature and inner diameter of tube on boiling heat transfer coefficient and critical quality were analyzed. Five boiling heat transfer correlations which are suitable to predict the boiling heat transfer coefficients of R290 in horizontal tube were chosen to obtain the calculated data compared with experimental data of boiling heat transfer coefficient. The correlation with the minimum error between calculated and experimental data among these five correlations was considered as the most suitable one for the investigation. The results showed that boiling heat transfer coefficient increased with the decrease of inner diameter of tube, with the increase of mass flux, or with the increase of saturated temperature. It increased first and then decreased with the increase of heat flux while vapor quality was increasing gradually. Heat flux and inner diameter had more evident effects on critical quality than mass flux and saturated temperature. Critical quality increased with the decrease of heat flux and inner diameter. Among the five correlations, Fang correlation showed the best capacity of prediction for the boiling heat transfer coefficients.

The influence of fluidization velocity in high and low velocity regions, height of static bed, and clapboard gap on internal flow of particles in internal circulating clapboard-type fluidized bed were experimentally studied by changing operating conditions and structural parameters. The results showed that the particle circulation rate was significantly affected by these four parameters. The particle circulation rate first increased and then decreased with the increase of one parameter while the other three parameters were kept unchanged. Hence, particle circulation is a nonlinear complex system of multiple operational and structural parameters. The La Nazue model was modified to predict the particle circulation rate without providing pressure drop between clapboard gap. The error between the calculated and experimental results for various particles was within 23%.

To verify the reliability of ionic liquids' molecular design method based on COSMO-SAC model, ionic liquids desulfurization mechanism analysis and experimental results are compared with COSMO simulation. By analyzing[HMIM] [BF₄],[HMIM] [PF₆],[BMIM] [BF₄],[BMIM] [PF₆],[EMIM] [BF₄] and[EMIM] [PF₆] on mechanism level,[HMIM] [PF₆] was considered as a better extractive desulfurization agent than others, and the order of desulfurization efficiency was consistent with the calculation results from COSMO-SAC model. The experimental result shows that the difference between the COSMO simulation and experiments is not significant. In this study,[HMIM] [PF₆] was used as an extractive desulfurization agent to remove benzothiophene from fuels, and the change of sulfur content in model oil was determined by liquid chromatography. Through considering the effect of extraction temperature, time and the ratio of solvent to oil, the optimal operating conditions, 20℃, 40 min and 2:1 respectively, were determined in orthogonal experiment with an efficiency over 72.74%. With[HMIM] [PF₆] used as the deep extraction desulfurization solvent, the sulfur content decreased from 1200 μg·g^-1 to 6.98 μg·g^-1 by 4-stages extraction, which met the Phase Ⅴ Emission Standards in China.

Homologues separation is a key process in the production of high-purity drugs and chemicals. High-purity phosphatidylserine (PS) is widely used as drugs and functional additives; however PS often appears in a mixture with structurally similar homologues and the selective separation of phospholipid homologues remains challenging. Here, a novel extraction method was developed to separate PS and phosphatidylcholine (PC) with ionic liquids (ILs) as extractants. The effects of structure and concentration of ILs and temperature on extraction performance were investigated. The results showed that the structure of the IL's anion had a significant impact on the separation selectivity, and an obvious synergistic extraction effect between IL and polar diluent was observed. In 1-ethyl-3-methylimidazolium bromide([EMIm]Br)-methanol-hexane biphasic systems, the selectivity of PC to PS (S_PC/PS) reached up to 29.48, when the mole fraction of IL was only 5%. Additionally, ab initio calculations were used to explore the extraction mechanism, and the results indicated that the multiple hydrogen-bonding and electrostatic interactions were formed between phospholipids and ILs, which is probably beneficial for the selective separation of phospholipid homologues.

The application and mechanism of ionic liquids in extraction separation of hexavalent chromium and ferric iron from acid dipping electroplating sludge was studied on the basis of designability and soft acidity of the ionic liquids. The experimental results showed that alkyl chain length on iminazole ring had remarkable effect on efficacy of extraction separation and ionic liquid with[BF₄]^- anion had higher extraction separation efficiency than that with[PF₆]^- anion. Among the ionic liquids in the study,[Omim] [BF₄] exhibited best extraction separation efficiency of Cr⁶⁺/Fe³⁺ in electroplating sludge. Slope analysis, FTIR and Roman spectra suggested ionic association mechanism in this extraction separation, which imidazolium cation formed association complex with dichromate anion and entered into organic phase by extraction. Consequently the technique could be applicable for transforming electroplating sludge waste into resources.

A novel strategy to optimize intramolecular interaction of Z domain was proposed to improve alkali-tolerance of the domain of Staphylococcal protein A (SpA) and two mutants of Z domain, named as Z' domain and Z" domain, were prepared to evaluate their alkali tolerance as the ligand for protein A chromatography. The result of circular dichroism showed that both the mutants had the identical characteristic peaks to Z domain whilst Z' domain had higher α-helix content than Z" domain. At pH 6.0, heat transition temperature of Z' domain increased by 3.9℃ compared with domain Z whilst heat transition temperature of Z" domain increased merely by 1.6℃. It indicated that the introduction of more hydrophobic Ile at position 12 in Z' domain improved the stability of the Z' domain. Using Z, Z' and their tetrameric domains as the ligand for protein A adsorbents, adsorption performance of SpA adsorbents was evaluated after their exposure in alkaline solutions. The results demonstrated that domain Z' had a higher alkali tolerance among three domains and the tolerance was further improved by applying a tetrameric Z' domain. The research provided a new clue for the development of alkali-tolerance protein A ligand.

EDTS-GO nanocomposites were prepared by decorating graphene oxide (GO) with N-(trimethoxysilylpropyl) ethylenediaminetriacetic acid sodium (EDTS). Then EDTS-GO modified PVDF ultrafiltration membrane was prepared by introducing EDTS-GO through blending method. Contact angle results indicated that the hydrophilicity of PVDF membrane was improved owing to introducing EDTS-GO. This was due to EDTS-GO transferring to membrane surface during phase inversion, which was confirmed by FTIR. The effect of the EDTS-GO addition content on membrane property was investigated systematically. With an increase in EDTS-GO content, the water flux of EDTS-GO modified PVDF membrane initially increased and then decreased and reached to maximum of 711.2 L·(m²·h)^-1 in the 0.5% content. Furthermore, antifouling experiment demonstrated EDTS-GO modified PVDF ultrafiltration membrane possessed the stronger fouling-resistant performance than pristine PVDF ultrafiltration membrane.

To recover the residual water efficiently in the complex environment, the advanced membrane technology was employed. Based on the experiment apparatus of the semicontinuous supercritical reactions, the wettability-modified nanoporous ceramic membranes were achieved by using semicontinuous supercritical reactions. The microstructure and characterization of both hydrophilic and hydrophobic nanoporous membranes were investigated by the methods of the contact angle measurement, electron microscope scan and electron spectroscopy analysis. Based on the experimental system of vapor condensation heat transfer on a single tube, the investigation of condensate transport through the nanoporous membrane with and without wettability modificaion was carried out. The effects of typical parameters including coolant flow rate, mixture gas temperature, transmembrane pressure and water vapor volume fraction on heat and mass transfer performance are studied. To explore the mechanism of water transport in nanoscale channels with different surface wettability, the method of molecular dynamics simulation was employed. The transport of water through a single nanopore was simulated.

mathematical model was established for pressure-flow coupling system in gas flow equipment by mechanism modeling and step-response methods.The performance stability and control rapidity in gas flowmeter testing were improved by a decoupling control,active disturbance rejection control (ADRC).For the multivariable system of gas flow equipment,a decentralized ADRC integrated coupling effects,internal uncertainties,and external disturbance into a total disturbance,which was estimated by reduced-order extended state observer (RESO) and cancelled out by control law.The original coupling system was then decoupled into two subsystems of single-input and single-output and controlled by proportional differential controllers.Stability and stability margin of the ADRC controlled system were analyzed by frequency domain method.ADRC achieved system decoupling,reduced algorithm dependency on mathematical model,and improved system robustness.Simulation and experiment results show that ADRC algorithm has shorter settling time,better decoupling effect,greater disturbance rejecting capability,and more robust performance than PID controller.

Kernel distance-based support vector data description (SVDD) for batch process monitoring exhibited poor monitoring precision by setting control limit from the largest kernel distance in historical process dataset but ignoring hyperspherical irregularity in high dimensional space. A kernel similarity based SVDD monitoring method was proposed for batch process monitoring. Kernel similarity was taken as kernel function value between support vectors and data samples for testing. The weighted summation of kernel similarity and distance of support vectors at various time points was utilized to set dynamic control limit for data samples of batch process to be monitored. Batch process monitoring was achieved by judging if kernel distance of test sample exceeded the dynamic control limit. This monitoring method considered irregularity of hypersphere, local distribution characteristics of process dataset in high dimensional space, and spontaneity of data samples, so that it could improve accuracy in batch process monitoring. Method effectiveness was demonstrated by numerical simulation and metal etching process in semiconductor manufacturing.

It is often difficult to establish models for accurate time series prediction, as a result of time delay, nonlinearity, and multi-variable coupling characteristics in production processes. A time series prediction method was proposed by applying correlated process variables to time delayed analysis of convolutional neural network (CNN). First, appropriate correlated variables were selected and time series were analyzed between these variables and outputs. Then, results of time series analysis were employed to determine length of temporal time windows of associated variables. Finally, appropriate CNN models were established for time series prediction. Experimental results of a reaction distillation process showed good accuracy in time series prediction of long time frame and large time-delay processes.

Through analysis of biological wastewater treatment process (WWTP), a multi-objective optimal control strategy was developed with targets of minimizing both energy consumption and amercement. A hybrid multi-objective barebones particle swarm optimization (HBBMOPSO) algorithm based on Pareto dominance and decomposition was proposed to improve convergence and diversity of optimized set of Pareto solutions. In HBBMOPSO, selection of personal leaders was determined from self-adaptive penalty factor decomposition while maintenance of external dossiers and selection of global leaders were determined from dominance and crowded distance. Furthermore, elitism learning strategy was adopted to facilitate particle escaping from local Pareto fronts. Finally, HBBMOPSO was combined with self-organizing fuzzy nerve network modeler and controller to realize dynamic optimization, intelligent decision, and background monitoring on dissolved oxygen and nitrate nitrogen in biological WWTP. Experimental study on international standardized simulator platform BSM1 showed that HBBMOPSO method can effectively reduce energy consumption under the premise of ensuring effluent to meet quality standard.

A structure-protection strategy was proposed to eliminate the deficiency since structures with great evolutionary potentials could be substituted with bad solutions when random walk algorithm with compulsive evolution (RWCE) was applied to heat exchanger network optimization. A new population evolving in parallel with the original population was set to execute structure protection. Individuals in the new population are corresponded with ones in the original population and received their current optimal solutions to form a protective effect. Meanwhile, a novel evolution technique named as “dimensionality-reduction local search” was proposed for the new population. The technique determined the search dimension by controlling the update probability of each dimension, which could tap the evolutionary potentials of the protected solutions fully and thus improving the local search ability. Moreover, major evolution operations of RWCE were adopted by the original population and thus the strong global search ability was maintained. The RWCE with the structure-protection strategy was applied to optimize heat exchanger network with stream splits, some results superior to the reported ones were obtained, demonstrating that the proposed method possessed strong abilities in both the global and local search and improved the search quality.

The liquid film phase change phenomenon not only changes the lubrication state of the end face, but also has a significant influence on the sealing performance and stability. The governing equations are discretized using the finite volume method. The influence of the structure parameters of spiral groove and the sealing condition on the sealing performance and phase change rate were studied. Results show that the opening force and leakage rate increase with the increase of the spiral angle, the number of grooves, groove depth, the pressure difference and the rotation speed; increase first and then decreases with the increase of the ratio of groove width in radial direction to surface width and the ratio of groove width to dam width, and take the maximum value when the ratio of groove width in radial direction to surface width ζ=0.5 and the ratio of groove width to dam width φ=0.7. The phase change rate increases with the increase of spiral angle and rotating speed, decreases with the increase of the number of grooves, groove depth, the pressure difference and the ratio of groove width to dam width, decreases first and then increases with the increase of the ratio of groove width in radial direction to surface width, and take the minimum value when the ratio of groove width in radial direction to surface width ζ=0.8. The phase transition process can be effectively inhibited by reasonable selection and combination of the parameters. The sealing performance can be improved by using the phase change phenomenon while ensuring the stability of the sealing operation.

The optimum reaction condition for hydrogen-enriched syngas production from waste activated carbon with Fe4ATP6 as oxygen carrier (OC) in chemical looping gasification (CLG) was investigated in high-temperature batch fluidized bed. It was demonstrated that Fe4ATP6 exhibited good reactivities during CLG process, and it had double effect of catalysis and lattice oxygen providing, which could enhance the carbon conversion rate and the gasification reaction rate. The optimum reaction condition was resulted to be 900℃, steam flow rate of 0.25 g·min^-1, and OC/C ratio of 1. Under the optimum reaction condition, 55.30% of H₂ average concentration, 1.09 L·g^-1 of H₂ yield, 1.20 L·g^-1 of syngas production and 92.15% of carbon conversion were achieved. The reactivity of Fe4ATP6 decreased slightly as a function of ten redox tests. Surface morphology and composition of Fe4ATP6 were analyzed by SEM and XRD, respectively. The results indicated that the structure of Fe4ATP6 changed significantly, while its particle size decreased slightly. In addition, unreactive iron silicates were found to be generated in Fe4ATP6 during the ten redox tests.

A novel single cylinder rotary compressor, which was increased a vapor injection hole near the discharge port, was adopted to improve the heating performance of a flash tank vapor injection air-source heat pump (FTHP) system at low ambient temperature. The effects of compressor frequency f and injection pressure p_inj on system performances of a R410A FTHP system were measured and investigated systematically. The results showed that both heating capacity and power consuming of the FTHP system increased with increasing the compressor frequency and injection pressure. The FTHP system power consuming at fixed frequency increased linearly with increasing injection pressure. The increasing rate of FTHP system heating capacity declined as the frequency and injection pressure increased. Therefore, the heating COP_h had a peak value at certain injection pressure when the frequency was low. After the peak point or at high frequency, the heating COP_h decreased as the frequency and injection pressure increased. In the range of 800 kPa to 1200 kPa and 50 Hz to 80 Hz, the maximum improvement of the FTHP heating capacity, power consuming, and COP_h were 27.55%, 30.75% and 7.1%, respectively, compared to the single stage compression system. In order to make the FTHP system efficiently, the control strategy must be optimized to keep the system operated at the optimum injection pressure and frequency.

The flue gas after FGD emitted in coal-fired power plant contains a large amount of water vapor,which means a great waste of water resources. The liquid desiccant-based dehumidification is a feasible technology to recover water from flue gas. To study the dehumidification performance of this technology, a laboratory scale adiabatic tube falling film dehumidifier was built with CaCl₂ solution as desiccant. The performance of this technology and the effect of solution temperature, concentration, mass transfer area and air inlet temperature was investigated. The mass transfer coefficient was given by 0.009-0.040 m·s^-1. Moreover, a comparison between condensation and liquid desiccant-based dehumidification was carried out. The data showed that the water recovery efficiency would be more than 50%, which was much better than condensation method and confirmed the feasibility of this technology applied in power plants.

Using Ca(NO₃)₂ as a precursor and SiO₂ as carrier, a supported CaO adsorbent was prepared. The selective adsorption performances of elemental mercury (Hg⁰) and mercuric chloride (HgCl₂) of the sorbent were conducted in a fixed bed, and the effects of SO₂ on CaO mercury adsorption process were also investigated. At the same time, combined with the program temperature desorption (TPD) and in situ diffuse reflectance infrared spectroscopy (in-situ DRIFT) characterization technology, the selective adsorption mechanism of CaO and the mechanism of SO₂ poisoning were deeply investigated. The mercury adsorption results showed that CaO maintained a breakthrough of nearly 100% for Hg⁰ in pure N₂ atmosphere and doped SO₂ atmosphere, while HgCl₂ manifested 66.0% and 60.3% adsorption efficiency in two atmospheres, respectively, indicating that there was a competitive adsorption relationship between SO₂ and HgCl₂ on CaO surface. The characterized results of CaO before and after adsorption suggested that as compared with Hg⁰, HgCl₂ was able to form monodentate, bidentate and other adsorption structure with the basic sites on the CaO surface. SO₂ and HgCl₂ formed a competitive adsorption relationship in the active sites where the bridged bidentate was easily formed, resulting in the reduction of adsorption efficiency of HgCl₂ on CaO.

To study the performance and selection of the working fluid pump in organic Rankine cycle (ORC) waste heat recovery system for vehicle engines, a test bench of a multistage centrifugal pump was constructed using R123 as working fluid in a condition of simulative ORC waste heat recovery system for vehicle engines. Experimental results of the multistage centrifugal pump under various operating conditions were obtained based on controlled working rotational speed (870-2900 r·min^-1) and working fluid flow rate (0.20-5.00 m³·h^-1). The interaction of the key pump parameters and their effect on the ORC performance were analyzed in this paper. In addition, the feasibility of the multistage centrifugal pump applied to the ORC waste heat recovery system for vehicle engines was verified and the optimal working point parameters were also determined. Results showed that the overall pump efficiency of multistage centrifugal pump was between 15.00% and 65.70%. The outlet pressure, pump efficiency and ORC thermal efficiency increased with the increase of the rotating speed of the pump. The flow rate needed to be regulated as the frequency became increasingly high. The maximum thermal efficiencies of the ORC system corresponding to various working frequencies of the pump were observed. Furthermore, the practical back work ratio (BWR) can reach up to 0.45 with the increase of the evaporating temperature of the ORC system. And the thermal efficiency can reach up to 10.50% when the rotating speed of multistage centrifugal pump was 2900 r·min^-1. Pumping power should not be neglected for small-scale ORC applications, and pump efficiency assumptions should be dependent on experiments. Low pump efficiency affected the increase of the thermal efficiency and net power of the ORC system.

Aiming at the problem of cold energy recycling, a cold energy utilization system combined with LNG and coal-burning waste gas power generation and natural gas re-liquefaction was proposed and the system was improved. The thermodynamic calculation of the original system and part of the improved system was made. The effects of evaporation pressure and temperature on the thermal performance of the system was analyzed in detail, the influences of natural gas liquefaction rate on the net power output of the system was analyzed. The optimal scope of power cycle optimal evaporating pressure, evaporation temperature and gas liquefaction rate was determined. The results showed that:calculating as the LNG cold energy recovery is 1000 kg·h^-1, the maximum net output of power generation system was 69.6 kW·h, cold energy recovery efficiency was 41.43%; the maximum value of liquefaction system LNG liquefaction rate was 24%; as the system was improved, the net output power and cold energy recovery efficiency of the power generation system increased by 17.85%, the liquefaction rate of LNG liquefaction system was improved to 28%. It provides a new way of thinking for the cold energy utilization in the process of LNG gasification.

Hydrothermal liquefaction of Undaria pinnatifida residue with n-propylamine solution was investigated, and the components of bio-oil, water-soluble substances and solid residue were analyzed. The highest bio-oil yield of 39.81% (mass) was obtained with n-propylamine concentration of 1.5 mol·L^-1, temperature 240℃, solid-to-liquid ratio 1:10. The results of GC-MS and FT-IR showed that the bio-oil consisted of alcohols, alkanes, esters, acids, phenols and amides, and also contained C=C, C=O, O-H and other chemical bonds. The results of HPLC and GC-MS analysis indicated that the main products of water-soluble substances were acids. Furtherly, XRD analysis of solid residue showed that the crystallization of cellulose decreased after hydrothermal liquefaction. The effect of temperature on the recovery of n-propylamine was also studied, and the recovery rate reached 92.56% at 100℃.

An ordered three-dimensional Si/void/C/graphene nanostructure composite was constructed by a simple self-assembly method combined with ultrasonication, freeze-drying, and thermal reduction. In this novel nanostructure, Si nanoparticles are completely sealed inside carbon shells with rationally designed void spaces between the Si nanoparticles and the carbon shell, which are in turn embedded in layers of graphene sheets. The well-defined void space allows the Si particles to expand freely without breaking the outer carbon shell. Meanwhile, the graphene layers further reinforce the Si/void/C structure and thus enhance the electrical conductivity of silicon anode material and substantially increase the electrochemical performance of silicon anode material. This novel ordered structure delivers a long-term stability of 1603 mA·h·g^-1 over 1000 cycles at a high current density of 4200 mA·g^-1 (1 C), and an excellent rate capability of 310 mA·h·g^-1 at 67 A·g^-1 (16 C), thus exhibiting great potential as an anode composite structure for durable high-rate lithium ion batteries.

Metal oxide sols can be prepared from metal alkoxides by hydrolyzation, which has been widely used in synthesis of nano-porous ceramic membranes by sol-gel method. However, the knowledge on hydrolysis mechanism of metal alkoxides is very limited. In this paper, TiO₂ sols were prepared by controlled hydrolyzation of titanium isopropoxide[Ti(i-OC₃H₇)₄] in isopropanol (i-C₃H₇OH). The formation of TiO₂ sols from the initial reactant mixtures with different molar ratios of H₂O/Ti(i-OC₃H₇)₄[Ti(i-OC₃H₇)₄:H₂O:i-C₃H₇OH=1:m:30] was charterized by small angle X-ray scattering (SAXS). The mechanism of formation and growth of colloidal particles is discussed. TiO₂ sol with a particle size less than 10 nm can be obtained. The formation and growth of colloidal particles are remarkably influenced by the molar ratio of H₂O/Ti(i-OC₃H₇)₄. When the molar ratio of H₂O/Ti(i-OC₃H₇)₄ ≥ 2.0, the stability of TiO₂ sol decreases with the molar ratio of H₂O/Ti(i-OC₃H₇)₄ increasing.

99.99% high-purity aluminum is introduced as anode material to obtain aluminum hydroxide, the precursor of alumina, by an electrochemical method. The influence of calcination temperature and holding time on preparing high purity and superfine alumina is discussed. And effects on morphology and size of alumina at different current densities are studied. Experimental results show that the average size of 268 nm aluminum hydroxide can be obtained at 70 mA·cm^-2, a relative high current density in aluminum/air batteries. After washing aluminum hydroxide and roasting at 1400℃, holding 3 h, the average size of 200 nm and near-spherical alumina powder is received. However, alumina particles agglomerate seriously at low current densities, which is mainly caused by narrowing of metastable zone width at high current densities.

Natural rubber (NR) latex foam is a typical cellular structure material manufactured by liquid latex compounds and has three dimension porous network structures. This kind of material has tremendous fire hazard because it is easily ignited and flame spreads extremely fast after ignited. Ignition position is one of the most important factors to determine the fire behavior of horizontal material. The aim of this study was to investigate the fire behavior of NR latex foam under center and edge ignition positions to provide the basic data for fire hazard evaluation of enclosure fire. Two types of experiments with center and edge ignition positions were carried out in a small-size flame spread experiment bench. The sample size was 25 cm×25 cm×2 cm with 6 mm diameter hole distribution in it. The temperature both on and above the sample surface and the flame front position were monitored during the experiment. The fire process was also recorded in horizontal and an angle of 45° to the horizontal direction. Then the flame height and flame spread rate were estimated. The results show that the maximum flame heights during the edge and center ignition condition test are 397 and 491 mm, respectively. The flame spread rates under the two ignition positions condition are 1.8 and 0.97 mm·s^-1, respectively. And the flame temperature under the edge ignition condition test is lower than that of the center ignition test.

In order to improve the drug loading, urea was used to insert into the montmorillonite interlayer by solid-phase grinding method. After this process, the ibuprofen was loaded by the solution blending to obtain ibuprofen/urea-montmorillonite (S(+)-IBU/urea-MMT) composite. The composites were characterized by X-ray diffraction (XRD) and Fourier transformed infrared (FT-IR) spectroscopy. The in vitro drug release behaviors of S(+)-IBU/urea-MMT were investigated by the dialysis method. Three models of in vitro drug release could be used to simulate the release performance of the S(+)-IBU/urea-MMT composites. The results show that the urea was intercalated into the montmorillonite layers, and the interlayer spacing of montmorillonite was enlarged from 1.20 to 1.79 nm. The maximum loading capacity of S(+)-IBU on the modified montmorillonite was 227.9 mg·g^-1, increased by a factor of 30%. In the artificial gastric juice (pH 1.2) and in the artificial intestinal juice (pH 6.8), the in vitro cumulative amount of the composites were 19.2% and 88.4% respectively. The variation of in vitro release rate can be well described by the zero order kinetics model.