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王宇新, Yuxin Wang, * Xing Zhong & Shichang Wang
J. Chem. Tech. Biotechnol. 1996, 67, 243-247,-0001,():
-1年11月30日
The enzymeβ-galactosidase was entrapped in poly (N-isopropylacrylamide) gel. The gel swelled or collapsed sharply upon the rise or fall of environmental pressure. The gel beads, prepared by reverse suspension polymerization, were placed in a stirred batch reactor filled with a solution of the substrate o-nitrophenol β-D-galactopyranoside. Operations under constant or cycling pressure were performed. A considerable increase in conversion rate was observed under pressure cycling operation, compared with isobaric operations at either atmospheric or high pressure. This result could be explained by the enhancement of mass transfer inside the gel beads during the pressure cycling operation.
enzyme immobilization,, mass transfer,, pressure-sensitive gel,, pressure-cycling,, β-galactosidase
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【期刊论文】Sulfonated poly (ether ether ketone) membranes for direct methanol fuel cell
王宇新, Lei Li a, b, Jun Zhang b, Yuxin Wang b, *
Journal of Membrane Science 226(2003)159-167,-0001,():
-1年11月30日
Sulfonated poly (ether ether ketone) (SPEEK) membranes with various degrees of sulfonation (DS) were prepared. Their proton conductivity and methanol permeability as a function of temperature were investigated. It was found that the proton conductivity of SPEEK membranes exceeded 10-2S/cm above 80℃, which is close to that of Nafion® 115 membrane under the same condition. The methanol permeability of SPEEK membranes was about an order of magnitude lower than that of Nafion® 115 membrane. The direct methanol fuel cell (DMFC) performance of the SPEEK membranes was better than that of Nafion® 115 membrane at 80℃
Poly (, ether ether ketone), (, PEEK), , Proton conductivity, Methanol permeability, Direct methanol fuel cell (, DMFC),
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【期刊论文】PRESSURE DEPENDENCE OF THE VOLUME PHASE-TRANSITION OF TEMPERATURE-SENSITIVE GELS
王宇新, XING ZHONG*, YU-XIN WANG, SHI-CHANG WANG
Chemical Engineerin 9 Science, Vol. 51, No. 12, pp. 3235-3239, 1996,-0001,():
-1年11月30日
The effect of hydrostatic pressure on the swelling of temperature-sensitive gels was studied by measuring the volume change of the beads of poly (N-isopropylacrylamide) gel, poly (N-n-propylacrylamide) gel, and poly (N, N-diethylacrylamide) gel under pressure up to 120atm. The excess enthalpy and the excess volume of the gel-water systems during the volume phase-transition of the gels were measured. These measurements are helpful in understanding that the pressure sensitivity of these gels originates from their temperature sensitivity and is the consequence of the increase of their LCST with pressure. An equation relating the LCST of the temperature-sensitive gel to the pressure was obtained through thermodynamical analysis. These efforts contribute to reveal the interdependence between the pressure sensitivity and the temperature sensitivity of hydrogel. Copyright.
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【期刊论文】Pervaporation membranes in direct methanol fuel cells
王宇新, Bryan S. Pivovar*, Yuxin Wang, E.L. Cussler
Journal of Membrane Science 154(1999)155-162,-0001,():
-1年11月30日
The membranes in direct methanol fuel cells must both conduct protons and serve as a barrier for methanol. Nafion, the most common fuel cell membrane, is an excellent conductor but a poor barrier. Polyvinyl alcohol pervaporation membranes are good methanol barriers but poor conductors. These and most other pervaporation membranes offer no significant advantages over Nafion in methanol fuel cell applications. However, polybenzimidazole membranes have demonstrated characteristics that suggest up to a 15-fold improvement in direct methanol fuel cells. This improvement may be due to an alternate form of proton conduction in which protons travel via a Grotthus or "hopping" mechanism.
Barrier membranes, Batteries, Solubility and partioning, Fuel cells
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【期刊论文】A methanol barrier polymer electrolyte membrane in direct methanol fuel cells
王宇新, Hong Wu, Yuxin Wang*, Shichang Wang
Journal of New Materials for Electrochemical Systems 5, 251-254 (2002),-0001,():
-1年11月30日
A successful membrane for direct methanol fuel cell (DMFC) must not only conduct proton, but also prevent methanol crossover. With such an aim, membranes of polyvinyl alcohol (PVA)-blend-polystyrene sulfonic acid (PSSA) were prepared. The effects of curing temperature, methanol concentration and membrane composition on the ionic conductivity and the methanol permeability of the membranes were investigated. A membrane with 17% PSSA showed ionic conductivity σof 3x10−3S/cm and methanol permeability P of 2x10-8cm2/sec. The membrane would perform about 40 times better than NafionTMmembrane, if the ratio (σ/P) is adopted to characterize the performance of a membrane for DMFC.
Polymer electrolyte membrane., Direct membrane fuel cells,, polyvinyl (, PVA), -blend polystyrene sulfonic acid (, PSSA), better than Nafion
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