2017 Vol. 32, No. 4
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2017, 32(4)
:1-7.
doi: 10.3969/j.issn.2096-1553.2017.4.001
Abstract:
Pt/Gr catalysts were prepared by organic-sol method with polyvinylpyrrolidone (PVP) as complexing agent.The catalysts were characterized by FT-IR, XRD and TEM, and the electrocatalytic performances of the catalysts for methanol oxidation in acid solution were measured. The results showed that the addition of appropriate amount of PVP could greatly improve the dispersion of Pt nanoparticles of Pt/Gr catalysts and reduce the particle size. The electrocatalytic performance and stability of Pt/Gr for methanol oxidation increased with the PVP contents firstly, and then decreased. When the maximum electrocatalytic activity (current density 0.53 A/mgPt) was reached,it was 2.4 times higher than that of Pt/Gr prepared without PVP,and Pt/Gr had higher stability at PVP content=10 mg.
Pt/Gr catalysts were prepared by organic-sol method with polyvinylpyrrolidone (PVP) as complexing agent.The catalysts were characterized by FT-IR, XRD and TEM, and the electrocatalytic performances of the catalysts for methanol oxidation in acid solution were measured. The results showed that the addition of appropriate amount of PVP could greatly improve the dispersion of Pt nanoparticles of Pt/Gr catalysts and reduce the particle size. The electrocatalytic performance and stability of Pt/Gr for methanol oxidation increased with the PVP contents firstly, and then decreased. When the maximum electrocatalytic activity (current density 0.53 A/mgPt) was reached,it was 2.4 times higher than that of Pt/Gr prepared without PVP,and Pt/Gr had higher stability at PVP content=10 mg.
2017, 32(4)
:8-15.
doi: 10.3969/j.issn.2096-1553.2017.4.002
Abstract:
Wormlike three dimensional (3D) porous graphene was prepared by microwave radiation pyrolysis expansion method.The morphology and pore structure of the as-prepared samples were characterized by SEM, TEM and N2 adsorption/desorption test.Simulated supercapacitors were assembled to perform electrochemical test by using the as-prepared 3D graphene.And the electrochemical properties were tested by cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance test. The results showed wormlike 3D porous structure was characterized by translucent gossamer-like morphology and had obvious folds belonging to grephene nanosheet. The sample showed a specific surface area of 158.7 m2·g-1 and an average pore size of 11.2 nm.The as-prepared graphene showed excellent electrochemical performances, with a specific capacitance of 161 F·g-1 at 1.25 A·g-1 and 91 F·g-1 when the current increased to 25.00 A·g-1. At 1.25 A·g-1,the capacity retention rate was 90% after cycling charge and discharge 5000 times,which indicated the cycle stability was excellent.
Wormlike three dimensional (3D) porous graphene was prepared by microwave radiation pyrolysis expansion method.The morphology and pore structure of the as-prepared samples were characterized by SEM, TEM and N2 adsorption/desorption test.Simulated supercapacitors were assembled to perform electrochemical test by using the as-prepared 3D graphene.And the electrochemical properties were tested by cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance test. The results showed wormlike 3D porous structure was characterized by translucent gossamer-like morphology and had obvious folds belonging to grephene nanosheet. The sample showed a specific surface area of 158.7 m2·g-1 and an average pore size of 11.2 nm.The as-prepared graphene showed excellent electrochemical performances, with a specific capacitance of 161 F·g-1 at 1.25 A·g-1 and 91 F·g-1 when the current increased to 25.00 A·g-1. At 1.25 A·g-1,the capacity retention rate was 90% after cycling charge and discharge 5000 times,which indicated the cycle stability was excellent.
2017, 32(4)
:16-20.
doi: 10.3969/j.issn.2096-1553.2017.4.003
Abstract:
In order to evaluate the corrosion resistance of metal bipolar plate in direct ethanol fuel cell (DEFC) environment, a solution of 0.05 mol/L H2SO4 +x mol/L CH3CH2OH (x=0,1,5,10,13) was used to simulate DEFC anode operating environment. In the environment, the surface morphology of 304 stainless steel (304SS) was characterized, and the electrochemical tests were carried out for polarization and constant current time-current density. The results showed that ethanol had not much effect on 304SS corrosion potential. Ethanol played a role in slowing the corrosion rate of 304SS in 0.05 mol/L H2SO4 solution. 304SS had a high stability in DEFC operating environment with high ethanol concentration.
In order to evaluate the corrosion resistance of metal bipolar plate in direct ethanol fuel cell (DEFC) environment, a solution of 0.05 mol/L H2SO4 +x mol/L CH3CH2OH (x=0,1,5,10,13) was used to simulate DEFC anode operating environment. In the environment, the surface morphology of 304 stainless steel (304SS) was characterized, and the electrochemical tests were carried out for polarization and constant current time-current density. The results showed that ethanol had not much effect on 304SS corrosion potential. Ethanol played a role in slowing the corrosion rate of 304SS in 0.05 mol/L H2SO4 solution. 304SS had a high stability in DEFC operating environment with high ethanol concentration.
2017, 32(4)
:21-29.
doi: 10.3969/j.issn.2096-1553.2017.4.004
Abstract:
Corn straw,rice straw and wheat straw were chosen as the substrates,and the effect of lime pretreatment time and temperature were comparatively examined by determination of the enzymatic transformation ratio.Results showed the yield of reducing sugar of wheat straw and rice straw could reach 60.38% and 46.77% respectively after lime pretreatment of 2 h at the temperature of 90 ℃.In contrast,corn straw needed more higher pretreated temperature of 121 ℃ for 1 h,whose yield of reducing sugar reached 56.82%.Wheat straw was more suitable for the pretreatment using lime.Further microstructural analysis of the straw samples was investigated by infrared spectrum,results showed that lime pretreatment could significantly degrade lignin in wheat straw. The selective degradation of lignin promoted the destruction of the spatial structure barrier of lignocellulosic macromolecules,retained more cellulose for later enzymatic saccharification, and improved straw enzymatic saccharification efficiency.
Corn straw,rice straw and wheat straw were chosen as the substrates,and the effect of lime pretreatment time and temperature were comparatively examined by determination of the enzymatic transformation ratio.Results showed the yield of reducing sugar of wheat straw and rice straw could reach 60.38% and 46.77% respectively after lime pretreatment of 2 h at the temperature of 90 ℃.In contrast,corn straw needed more higher pretreated temperature of 121 ℃ for 1 h,whose yield of reducing sugar reached 56.82%.Wheat straw was more suitable for the pretreatment using lime.Further microstructural analysis of the straw samples was investigated by infrared spectrum,results showed that lime pretreatment could significantly degrade lignin in wheat straw. The selective degradation of lignin promoted the destruction of the spatial structure barrier of lignocellulosic macromolecules,retained more cellulose for later enzymatic saccharification, and improved straw enzymatic saccharification efficiency.
2017, 32(4)
:30-36.
doi: 10.3969/j.issn.2096-1553.2017.4.005
Abstract:
The effects of constant temperature fermentation time on poly-γ-glutamic acid (γ-PGA) production by B.amyloliquefaciens YP-2 was investigated under different temperatures (31 ℃, 33 ℃, 35 ℃, 37 ℃ and 39 ℃). The scheme of step-wise temperature control (0~4 h, 35 ℃; 4~7 h, 31 ℃; 7~10 h, 33 ℃;10~26 h, 37 ℃;26~60 h,31 ℃) was formulated following the kinetic analysis of γ-PGA fermentation. Under the variable temperature fermentation condition, the maximum cell productivity and γ-PGA yield reached 1.66 g/(L·h)-1 and 29.50 g/L, respectively, which was 4.4% and 11.8% higher than those in optimal constant temperature at 37 ℃. The results indicated the variable temperature fermentation effectively improved the γ-PGA production by B.amyloliquefaciens YP-2 comparing with constant temperature fermentation.
The effects of constant temperature fermentation time on poly-γ-glutamic acid (γ-PGA) production by B.amyloliquefaciens YP-2 was investigated under different temperatures (31 ℃, 33 ℃, 35 ℃, 37 ℃ and 39 ℃). The scheme of step-wise temperature control (0~4 h, 35 ℃; 4~7 h, 31 ℃; 7~10 h, 33 ℃;10~26 h, 37 ℃;26~60 h,31 ℃) was formulated following the kinetic analysis of γ-PGA fermentation. Under the variable temperature fermentation condition, the maximum cell productivity and γ-PGA yield reached 1.66 g/(L·h)-1 and 29.50 g/L, respectively, which was 4.4% and 11.8% higher than those in optimal constant temperature at 37 ℃. The results indicated the variable temperature fermentation effectively improved the γ-PGA production by B.amyloliquefaciens YP-2 comparing with constant temperature fermentation.
2017, 32(4)
:37-42.
doi: 10.3969/j.issn.2096-1553.2017.4.006
Abstract:
Conjugating the EDC activated fluorescent microspheres with antibody to prepare the fluorescence chromatographic strip for simultaneous detection of tPSA and fPSA. The performance analysis and methodological comparison for the test strip were further performed. The results showed that the sensitivity for PSA and fPSA detection by the test strip were 0.08 ng/mL and 0.06 ng/mL, respectively. The coefficient of variation within and between groups was less than 10% and 15%, respectively. The recovery rates ranged from 95% to 105%. The specificity of the test strip was well. The results revealed a good correlation between self-prepared test strip and electrochemiluminescence detection, which could satisfy the needs of aided diagnosis of small-scale hospitals.
Conjugating the EDC activated fluorescent microspheres with antibody to prepare the fluorescence chromatographic strip for simultaneous detection of tPSA and fPSA. The performance analysis and methodological comparison for the test strip were further performed. The results showed that the sensitivity for PSA and fPSA detection by the test strip were 0.08 ng/mL and 0.06 ng/mL, respectively. The coefficient of variation within and between groups was less than 10% and 15%, respectively. The recovery rates ranged from 95% to 105%. The specificity of the test strip was well. The results revealed a good correlation between self-prepared test strip and electrochemiluminescence detection, which could satisfy the needs of aided diagnosis of small-scale hospitals.
2017, 32(4)
:43-48.
doi: 10.3969/j.issn.2096-1553.2017.4.007
Abstract:
α-ionol was synthesized from α-ionone via the selective reduction.α-ionol-β-D-glucoside was synthesized from α-ionol via the reaction with tetra-O-α-acetyl-D-glucopyranosyl bromide under the phase transfer catalyst to give the corresponding α-ionol-2,3,4,6-tetra-O-acetyl-β-D-glucoside,followed by deacetylation.The appropriate conditions for this glucosidation reaction were as follows:10% tetrabutyl ammonium bromide was added to catalyze a reaction between Br-glucose-tetraacetateand α-ionol at a ratio of 1.6:1 in CHCl3-H2O allowed to proceed for 8 h at 60 ℃.The yield rate of glycosylation reaction was 30%.The target products were characterized β-configuration by FT-IR,1H NMR and ESI-MS.
α-ionol was synthesized from α-ionone via the selective reduction.α-ionol-β-D-glucoside was synthesized from α-ionol via the reaction with tetra-O-α-acetyl-D-glucopyranosyl bromide under the phase transfer catalyst to give the corresponding α-ionol-2,3,4,6-tetra-O-acetyl-β-D-glucoside,followed by deacetylation.The appropriate conditions for this glucosidation reaction were as follows:10% tetrabutyl ammonium bromide was added to catalyze a reaction between Br-glucose-tetraacetateand α-ionol at a ratio of 1.6:1 in CHCl3-H2O allowed to proceed for 8 h at 60 ℃.The yield rate of glycosylation reaction was 30%.The target products were characterized β-configuration by FT-IR,1H NMR and ESI-MS.
2017, 32(4)
:49-57.
doi: 10.3969/j.issn.2096-1553.2017.4.008
Abstract:
Using discarded tobacco leaves as raw materials,through aroma-bacterial screening and aroma components extracting,tobacco endogenous derived flavor was prepared and comparison was made on chemical components and sensory with tobacco leaf extract.Result indicated that: 1)11 pure aroma-bacteria and 2 pure aroma-yeast were screened from 65 aroma-bacteria and 17 aroma-yeast.An Aureobasidium pullulans OF-01 was gotten by the style character evaluation eventually,and used for tobacco leaf flavor preparation; 2)A tobacco derived flavor was prepared by OF-01 strains through fermenting extracting,and concentrating.By comparison of the tobacco water extract,acids (586.18%),phenols (235.04%),and the alcoholes aldehydes (308.12%) in tobacco derived flavor promote greatly,and the quantities of scholar ketone,3-hydroxy-2-butanone,and benzaldehyde incense increased over 1000%; 3)The tobacco derived flavor could increase armor,smooth smoke,reduce irritation,hide offensive and improve the effects of cigarette smoking.It had better compatibility with Yunnan cigarette,and could be used as flavor in cigarette production.
Using discarded tobacco leaves as raw materials,through aroma-bacterial screening and aroma components extracting,tobacco endogenous derived flavor was prepared and comparison was made on chemical components and sensory with tobacco leaf extract.Result indicated that: 1)11 pure aroma-bacteria and 2 pure aroma-yeast were screened from 65 aroma-bacteria and 17 aroma-yeast.An Aureobasidium pullulans OF-01 was gotten by the style character evaluation eventually,and used for tobacco leaf flavor preparation; 2)A tobacco derived flavor was prepared by OF-01 strains through fermenting extracting,and concentrating.By comparison of the tobacco water extract,acids (586.18%),phenols (235.04%),and the alcoholes aldehydes (308.12%) in tobacco derived flavor promote greatly,and the quantities of scholar ketone,3-hydroxy-2-butanone,and benzaldehyde incense increased over 1000%; 3)The tobacco derived flavor could increase armor,smooth smoke,reduce irritation,hide offensive and improve the effects of cigarette smoking.It had better compatibility with Yunnan cigarette,and could be used as flavor in cigarette production.
2017, 32(4)
:58-65.
doi: 10.3969/j.issn.2096-1553.2017.4.009
Abstract:
Based on the fact that the simulation model of permanent magnet synchronous motor (PMSM) vector control system of demagnetization fault was built based on Matlab/Simulink platform,the diagnosis method of demagnetization fault of PMSM was presented using the control mode of id=0.The ratio of the electromagnetic torque and the stator current was used as the magnetic failure factor,the ratio of the electromagnetic torque and the stator current in normal operation was used as the threshold.If the magnetic failure factor was less than the threshold, the magnetic field could be judged demagnetization fault.And according to the magnitude of the magnetic failare factor and the threshold value, the magnetic field could be judged the severity of the loss.The simulation results verified the validity of the method.
Based on the fact that the simulation model of permanent magnet synchronous motor (PMSM) vector control system of demagnetization fault was built based on Matlab/Simulink platform,the diagnosis method of demagnetization fault of PMSM was presented using the control mode of id=0.The ratio of the electromagnetic torque and the stator current was used as the magnetic failure factor,the ratio of the electromagnetic torque and the stator current in normal operation was used as the threshold.If the magnetic failure factor was less than the threshold, the magnetic field could be judged demagnetization fault.And according to the magnitude of the magnetic failare factor and the threshold value, the magnetic field could be judged the severity of the loss.The simulation results verified the validity of the method.
2017, 32(4)
:66-72.
doi: 10.3969/j.issn.2096-1553.2017.4.010
Abstract:
The tripolar electrostatic adhesion model was proposed based on the characteristic of the electric field distribution of the electrostatic aolhesion array for deficiency of existing electrostatic adhesion methods.The finite element analysis method was used to optimize the electrode gap,electrode width and the thickness of insulation layer of the electrostatic aolhesion array for maximal adhesion force output.Experimental results and finite element simulation had good consistency, to verify the effectiveness of the tripolar structure design.In the actual design process, in meet the breakdown characteristics between the electrode and wear-resisting properties of insulation layer surface, it should reduce the electrode width and the thickness of insulating layer, increase the number of electrodes, so as to increase the overall length of the edge of the electrode array to improve the adsorption force of electrostatic adsorption array.
The tripolar electrostatic adhesion model was proposed based on the characteristic of the electric field distribution of the electrostatic aolhesion array for deficiency of existing electrostatic adhesion methods.The finite element analysis method was used to optimize the electrode gap,electrode width and the thickness of insulation layer of the electrostatic aolhesion array for maximal adhesion force output.Experimental results and finite element simulation had good consistency, to verify the effectiveness of the tripolar structure design.In the actual design process, in meet the breakdown characteristics between the electrode and wear-resisting properties of insulation layer surface, it should reduce the electrode width and the thickness of insulating layer, increase the number of electrodes, so as to increase the overall length of the edge of the electrode array to improve the adsorption force of electrostatic adsorption array.
2017, 32(4)
:73-80.
doi: 10.3969/j.issn.2096-1553.2017.4.011
Abstract:
To overcome the problems of slow response speed and uneven thermal conductivity caused by the heterogeneity structure which exits in recent junction temperature measurements,a thermoelectric model based on heat accumulation was proposed to accurately measure the IGBT junction temperature in real time,based on the study of IGBT failure mechanism and the existing junction temperature measurement models.The IGBT temperature measurement was converted to measure the temperature of a certain point of the IGBT based on the energy balance to avoid the heterogeneity structure problem of IGBT.Matlab simulation and experimental results showed that the two temperature curves have a good degree of fit, verified the feasibility of the proposed method.
To overcome the problems of slow response speed and uneven thermal conductivity caused by the heterogeneity structure which exits in recent junction temperature measurements,a thermoelectric model based on heat accumulation was proposed to accurately measure the IGBT junction temperature in real time,based on the study of IGBT failure mechanism and the existing junction temperature measurement models.The IGBT temperature measurement was converted to measure the temperature of a certain point of the IGBT based on the energy balance to avoid the heterogeneity structure problem of IGBT.Matlab simulation and experimental results showed that the two temperature curves have a good degree of fit, verified the feasibility of the proposed method.
2017, 32(4)
:81-86.
doi: 10.3969/j.issn.2096-1553.2017.4.012
Abstract:
For the enhancement of integration level and calorific value of micro-electro-mechanical and microelectronics components, wave mini-channel heat sinks (WMS) which could enhance secondary flow of the fluid in mini-channel were designed.On the basis of this structure, the secondary flow passages were added to further improve its heat transfer characteristics. CFD software was used to simulate WMS with and without secondary passage and to investigate the effect on heat transfer in laminar flow state. The results showed that, as far as this study was concerned, when the Re of inlet fluid was less than 1008, the heat transfer characteristic of WMS with secondary passages was better than the one of WMS; secondary passages didn’t improve the temperature uniformity of mini-channel heat sink back surface. Then, through the analysis of the field synergy theory, it was found that secondary passages improved the synergy degree between velocity field and temperature field of wave mini-channel at the low Re, the heat transfer ability of WMS was improved.
For the enhancement of integration level and calorific value of micro-electro-mechanical and microelectronics components, wave mini-channel heat sinks (WMS) which could enhance secondary flow of the fluid in mini-channel were designed.On the basis of this structure, the secondary flow passages were added to further improve its heat transfer characteristics. CFD software was used to simulate WMS with and without secondary passage and to investigate the effect on heat transfer in laminar flow state. The results showed that, as far as this study was concerned, when the Re of inlet fluid was less than 1008, the heat transfer characteristic of WMS with secondary passages was better than the one of WMS; secondary passages didn’t improve the temperature uniformity of mini-channel heat sink back surface. Then, through the analysis of the field synergy theory, it was found that secondary passages improved the synergy degree between velocity field and temperature field of wave mini-channel at the low Re, the heat transfer ability of WMS was improved.
2017, 32(4)
:87-92.
doi: 10.3969/j.issn.2096-1553.2017.4.013
Abstract:
An experiment was carried out on the performance of water-resource heat pump water heater under various inlet water temperature of evaporating side.The results showed that the discharge pressure, discharge temperature and power input were increased with hot water temperature; and the heating power and COP were decreased with hot water temperature. The coefficient of the system was increased with inlet water temperature on the evaporator side. The heating power of the system was 22.83 kW, 25.95 kW, 27.31 kW, the power consumption of the system was 5.30 kW,5.58 kW,5.84 kW, and the coefficient of the system was 4.31, 4.65 and 5.64 on conditions of evaporator inlet water temperature of 12 ℃, 15 ℃ and 30 ℃, respectively.
An experiment was carried out on the performance of water-resource heat pump water heater under various inlet water temperature of evaporating side.The results showed that the discharge pressure, discharge temperature and power input were increased with hot water temperature; and the heating power and COP were decreased with hot water temperature. The coefficient of the system was increased with inlet water temperature on the evaporator side. The heating power of the system was 22.83 kW, 25.95 kW, 27.31 kW, the power consumption of the system was 5.30 kW,5.58 kW,5.84 kW, and the coefficient of the system was 4.31, 4.65 and 5.64 on conditions of evaporator inlet water temperature of 12 ℃, 15 ℃ and 30 ℃, respectively.
2017, 32(4)
:93-99.
doi: 10.3969/j.issn.2096-1553.2017.4.014
Abstract:
By using the 3D control equations of incompressible fluid flow,a mathematical model of a new energy automotive battery cooling plate heat transfer was established. Using this model, selection of glycol water solution as cooling medium,at initial temperature of 15 ℃,with the boundary condition of the quality of imported flow heat of 0.179 kg/s transfer analysis was made.The heat transfer effect is good, but there were problems of low heat transfer efficiency and large cooling plate quality.The original scheme of internal grid structure was changed to plate fin structure and internal structure was analyzed and optimized by orthogonal test. The cooling plate weight was reduced by 13.9% after optimization.Because the heat transfer area increases, heat power increased by 11.36% to achieve the purpose of optimization design.
By using the 3D control equations of incompressible fluid flow,a mathematical model of a new energy automotive battery cooling plate heat transfer was established. Using this model, selection of glycol water solution as cooling medium,at initial temperature of 15 ℃,with the boundary condition of the quality of imported flow heat of 0.179 kg/s transfer analysis was made.The heat transfer effect is good, but there were problems of low heat transfer efficiency and large cooling plate quality.The original scheme of internal grid structure was changed to plate fin structure and internal structure was analyzed and optimized by orthogonal test. The cooling plate weight was reduced by 13.9% after optimization.Because the heat transfer area increases, heat power increased by 11.36% to achieve the purpose of optimization design.
2017, 32(4)
:100-104.
doi: 10.3969/j.issn.2096-1553.2017.4.015
Abstract:
The finite-time synchronization control problem of a class of fractional order chaos system was studied based on Lyapunov stability theory and fractional order system theory.Two sufficient conditions for fast synchronization of master-slave systems were gotten.Numerical simulation result verified the effectiveness of the proposed method.
The finite-time synchronization control problem of a class of fractional order chaos system was studied based on Lyapunov stability theory and fractional order system theory.Two sufficient conditions for fast synchronization of master-slave systems were gotten.Numerical simulation result verified the effectiveness of the proposed method.
2017, 32(4)
:105-108.
doi: 10.3969/j.issn.2096-1553.2017.4.016
Abstract:
The existence of nonunique fixed points for a class of mappings in orbitally complete 2-metric spaces was studied,a new nonunique fixed point theorem was proved.And the results obtained in the metric space in the relevant literature were extended to the 2-metric spaces.
The existence of nonunique fixed points for a class of mappings in orbitally complete 2-metric spaces was studied,a new nonunique fixed point theorem was proved.And the results obtained in the metric space in the relevant literature were extended to the 2-metric spaces.
Journal Information
Founded in 1986， bimonthly
Administered by：The Education Department Henan Province
Sponsored by：Zhengzhou University of Light Industry
Editor-in-chief：Wei Shizhong
Executive Editor-in-Chief：Zou Lin
Subeditor：Qu Shuanghong
Edited & published by：Editorial Department of Journal of Light Industry
CN 41-1437/TS
ISSN 2096-1553
Address：136 Science Avenue, Zhengzhou City, Henan Province, China
Postal Code：450001
Tel：(086)0371-86608635
(086)0371-86608633
