A feature subspace based kernel principal component analysis(KPCA),method (FS_KPCA)and its application to fault detection and diagnosis are presented in this paper to overcome the shortcoming of the standard KPCA method which is not appropriate to deal with a large number of training data.FS_KPCA simplifies the kernel matrix and reduces the computational cost of KPCA by constructing a lower-dimensional orthonormal based on feature subspace.When applied to process monitoring, the FS_KPCA-based method is more efficient in computation and needs less computer memory than standard KPCA-based methods.Computer simulation of non-isothermal CSTR process monitoring demonstrates the effectiveness and efficiency of the proposed method.

A novel design of reference electrode was developed to in-situ measure the polarization of direct methanal fuel cell(DMFC).The effect of humidification conditions of electrolyte on the reference electrode potential and its potential stability was investigated.The experiment results showed that the potential of reversible hydrogen electrode (RHE), acting as the reference electrode of DMFC, decreased with increasing degree of electrolyte humidification.It was found that the potential stability of RHE was mainly determined by the stability of its surface state.To obtain stable and accurate polarization curves, it was suggested that the electrolyte located on RHE should be humidified by liquid water on its opposite side and the flow rate of H₂ should be controlled at an appropriate and stable value.

Immobilization of the bacterium Rhodococcus erythropolis DS-3 cells, which was isolated from the oil-soaked soil of Gudao oilfield and could decompose dibenzothiophene (DBT) by 4S pathway, was studied.The effects of immobilization conditions on the bacterium’s bio-desulfurization characteristics and on desulfurization of diesel fuel were investigated.The results showed that the immobilized cells with sodium alginate and polyvinyl alcohol as the immobilized carrier and 1 mmol·L^-1 dimethyl sulfoxide as the culture medium showed good bio-desulfurization characteristics and long natural life.The optimum immobilized condition was 4℃ crosslinking temperature with the concentrations of sodium alginate 2%, polyvinyl alcohol 8%,cells to mixed carrier ratio 0.1 g·ml^-1 and calcium chloride content 2%.After three cycles of circulated desulfurization, the content of DBT decreased from 0.5 to 0.011 mmol·L^-1, the overall rate of desulfurization was 93%, and the average desulfurization efficiency was about 0.225 mg DBT ·(g DCW)^-1·h^-1.The refined diesel fuel with sulfur content 340 mg·L^-1 could be desulfurized by immobilized cells to a low sulfur content of 42 mg·L^-1.Furthermore, the reuse and life periods of immobilized cells were much better than unimmobilized cells.The life periods of the reactivated immobilized cells reached more than 250 h.DS-3 could utilize alcohol, saturated aliphatic alkane which has a C₈—C₁₅ carbon chain as its sole carbon source, but could not utilize cycloalkane, aromatic hydrocarbon and saturated aliphatic alkane which has a carbon chain shorter than hexane or longer than hexadecane.The preference of carbon source was in the order of ethanol, glucose and alkane.GC-FID analysis of refined diesel fuel before and after bio-desulfurization showed that the composition of alkane had little change during bio-desulfurization.It was indicated that the desulfurization of DS-3 specifically cut carbon sulfur bond but had no effect on alkane.

A novel batch-fed hydrolytic-aerobic recycling process was used in the treatment of PEG-containing waste water and the performance of the process was studied.When the concentration of PEG6000 and COD_Cr were 1.0 g·L^-1 and 2300 mg·L^-1 respectively，the hydrolytic-aerobic recycling process could better degrade PEG than the single hydrolytic or aerobic sequencing batch reactor（SBR）process.The recycling rate and volume ratio of hydrolytic and aerobic system were two important parameters，which influenced the treatment capacity of the recycling process.