Enhancing catalytic activity of multi-enzyme in vitro through substrate channeling effect is promis-ing yet challenging.Herein,conjugated microporous polymers(CMPs)-scaffolded integrated en-zyme cascade systems(I-ECSs...Enhancing catalytic activity of multi-enzyme in vitro through substrate channeling effect is promis-ing yet challenging.Herein,conjugated microporous polymers(CMPs)-scaffolded integrated en-zyme cascade systems(I-ECSs)are constructed through co-entrapping glucose oxidase(GOx)and horseradish peroxidase(HRP),in which hydrogen peroxide(H_(2)O_(2))is the intermediate product.The interplay of low-resistance mass transfer pathway and appropriate pore wall-H_(2)O_(2)interactions facilitates the directed transfer of H_(2)O_(2),resulting in 2.4-fold and 5.0-fold elevation in catalytic activ-ity compared to free ECSs and separated ECSs,respectively.The substrate channeling effect could be regulated by altering the mass ratio of GOx to HRP.Besides,I-ECSs demonstrate excellent stabili-ties in harsh environments and multiple recycling.展开更多
Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid (FA) ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 n...Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid (FA) ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging (MRI) target detection and magnetic hyperthermia.展开更多
[Objective] The paper was to compare the quality of apple vinegars prepared by different methods and screen an optimum brewing method for apple vinegar production. [Methed] The quality of apple vinegar brewed by three...[Objective] The paper was to compare the quality of apple vinegars prepared by different methods and screen an optimum brewing method for apple vinegar production. [Methed] The quality of apple vinegar brewed by three traditional brewing methods and a new method developed by our previous work was analyzed. Three traditional methods were solid state fermentation (SSF), liquid state fermentation (LSF) and immobilized microorganism fermentation (IMF), and the new method was multi-microorganisms co-immobilization technology(MMCT), which used co-immobilized beads of ethanol-producing yeast, aroma-improving yeast and lactic acid bacteria (with a ratio of 6:3:1) for alcoholic fermentation and then used immobilized acetic acid bacteria for vinegar fermentation. [Result] The general quality of apple vinegar brewed by MMCT was superior to the others. Its total acidity reached to 3.845 g/100 ml, unvolatile acidity was about 0.600 g/100 ml, amino-nitrogen was higher than 0.510 g/100 ml, and the composing of flavor compounds was almost similar to that of SSF brewed apple vinegar. [Conclusion] The MMCT method was proven to be the optimum one for high quality apple vinegar brewing and might be widely used in the future.展开更多
An electromechanical nonlinear model of rotor system of electric machine is built.Respondance curves in parameter excited nonlinear vibration of this system caused by electromagnetic forces are investigated.Further mo...An electromechanical nonlinear model of rotor system of electric machine is built.Respondance curves in parameter excited nonlinear vibration of this system caused by electromagnetic forces are investigated.Further more,the analysis reveals the effects of various electromagnetic and mechanical parameters on resonances, and some valuable results are obtained.The analytical result of this paper provides electric machine with the condition of 1/2 subharmonic resonance under the electromechanical electromagnetic forces.Electromagnetic forces apparently affect the stability zone, and both linear term and nonlinear term can excite parametric resonance.The revealed dynamic phenomena provide some new theories and active methods for the fault recognition of electric machine and the defination of stability range,and the theoretical bases for qualitatively controlling the stable operating state of rotors.展开更多
The recent progress of non-covalent associative structure of coal, and the mechanisms of the CS2/NMP (1:1 by volume) mixed solvent and the additive addition enhancing the extraction yield of coals were reviewed, and t...The recent progress of non-covalent associative structure of coal, and the mechanisms of the CS2/NMP (1:1 by volume) mixed solvent and the additive addition enhancing the extraction yield of coals were reviewed, and the aggregation behavior of coal in solid and solution states were presented, and the aggregation behavior of coal in solid and solution states were introduced in this paper. Coal extraction and swelling in organic solvents at room temperature were the most useful methods to understand the associative structure of coal. CS2/NMP (1:1 by volume) is a unique solvent to give high extraction yields for some bituminous coals. Some additives can dissociate the stronger interactions among coal molecules and enhance the extraction yields of coal in the mixed solvent.展开更多
The time has come for the constitution of the Association of Southeast Asian Nations (ASEAN) economic community and many facts have been analyzed regarding this topic. This paper presents the results of the statisti...The time has come for the constitution of the Association of Southeast Asian Nations (ASEAN) economic community and many facts have been analyzed regarding this topic. This paper presents the results of the statistical analysis applied to several economic parameters which firstly show how their integration pattern adjusts with a considerable good fitting to the optimum currency area model and to its extended version by Behrens; and secondly how the 10 members of this group are moving at relatively same speed in spite of their differences, that are also inferred for ranging.展开更多
The effect of the correlation of two dichotomous noises on stochastic resonance is investigated for a linear stochastic system subject to a periodic oscillatory signal. It is found that, the correlation between the tw...The effect of the correlation of two dichotomous noises on stochastic resonance is investigated for a linear stochastic system subject to a periodic oscillatory signal. It is found that, the correlation between the two dichotomous noises can not only affect the appearance of the stochastic resonance phenomenon, but also the distinctness of the stochastic resonance phenomenon. There is an optimal value of the correlation, at which the stochastic resonance phenomenon is most distinct. In addition, the correlation between the two dichotomous noises can also cause the movement of the peak of stochastic resonance. Finally, two stochastic resonances caused by two correlated multiplicative dichotomous noises can be found in this system.展开更多
In order to deal with the complex association relationships between classes in an object-oriented software system,a novel approach for identifying refactoring opportunities is proposed.The approach can be used to dete...In order to deal with the complex association relationships between classes in an object-oriented software system,a novel approach for identifying refactoring opportunities is proposed.The approach can be used to detect complex and duplicated many-to-many association relationships in source code,and to provide guidance for further refactoring.In the approach,source code is first transformed to an abstract syntax tree from which all data members of each class are extracted,then each class is characterized in connection with a set of association classes saving its data members.Next,classes in common associations are obtained by comparing different association classes sets in integrated analysis.Finally,on condition of pre-defined thresholds,all class sets in candidate for refactoring and their common association classes are saved and exported.This approach is tested on 4 projects.The results show that the precision is over 96%when the threshold is 3,and 100%when the threshold is 4.Meanwhile,this approach has good execution efficiency as the execution time taken for a project with more than 500 classes is less than 4 s,which also indicates that it can be applied to projects of different scales to identify their refactoring opportunities effectively.展开更多
In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil ...In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil samples. The preheating temperature had a great influence on the viscosity of oil samples and the resolution of spectral analysis. The repeatability of spectral measurements was impacted by the metal and wax content of the oil samples. For the case of high wax content oils, the wax species began to crystallize in the course of determination that could affect the repeatability of spectral measurements. These factors have evidenced why the preheating devices and filter unit are necessary when low field NMR system is used in the online analysis process. The investigation is very important for the on-line application of the low field NMR.展开更多
Two kinds of St/DVB copolymer beeds containing (1 - pyrenyl) formyl and(1 -pyrenyl) methyl groups respectively have been synthesized by both functionalization and copolymerization. The fluorescence spectra of the swo...Two kinds of St/DVB copolymer beeds containing (1 - pyrenyl) formyl and(1 -pyrenyl) methyl groups respectively have been synthesized by both functionalization and copolymerization. The fluorescence spectra of the swollen polymers synthesized are similar in shape to those of the corresponding model compounds, whilethe intensity ratio of excimer to monomer shows clear dependence on the contents ofthe pyrene groups.展开更多
The IR absorption, visible excited normal Raman, and UV-excited near-resonant Raman (UVRR) spectra of 1,1'-binaphthyl-2,2'-diamine (BINAM) were measured and analyzed. Density functional theory calculations were ...The IR absorption, visible excited normal Raman, and UV-excited near-resonant Raman (UVRR) spectra of 1,1'-binaphthyl-2,2'-diamine (BINAM) were measured and analyzed. Density functional theory calculations were carried out to investigate its vibrational frequencies, infrared absorption, normal Raman, and near-resonance Raman intensities. The observed Raman and IR bands of BINAM were assigned with respect to the local vibrations of substituted 2-naphthylamine. Several Raman bands of BINAM were found selectively enhanced in the UVRR in comparison with the normal Raman spectrum. Possible excited state geometry distortion was discussed based on the resonance Raman intensity analysis.展开更多
This paper summarizes the results of the international questionnaire survey which took place at the start of 2013 in order to examine, judge, and compare the implemented concept and procedures of human resource manage...This paper summarizes the results of the international questionnaire survey which took place at the start of 2013 in order to examine, judge, and compare the implemented concept and procedures of human resource management in the questioned building companies operating in the Visegrad Four countries (the Czech Republic, Hungary, Poland, and the Slovak Republic) and the Federal Republic of Germany, and proposes an optimal approach to human resource management in the context of the current and expected economic development. The questionnaire survey was based on the assumption that effective human resource management is a condition of the successful function of each building company and that human resource management is that area of management which distinguishes the successful building companies from the unsuccessful ones. In total, 202 companies from the Czech Republic, 105 companies from Hungary, 100 companies from Poland, 102 companies from the Slovak Republic, and 99 companies from the Federal Republic of Germany took part in the questionnaire survey. The results of the questionnaire survey showed that among the building companies questioned in individual countries, there was no substantial difference in the overall concept and in the partial procedures of human resource management. The implemented concept and procedures in the questioned building companies show significant merits and surprising shortcomings, whereas it is difficult to prove an unequivocal connection between the efficiency of human resource management and the success of building companies. This relationship is determined by a series of other political, economic, legal, social, cultural, technical, demographic, and natural effects which are not related to the efficiency of human resource management or to the performance of the workforce of building companies.展开更多
This article aims to analyze the so-called“starting point”when modern scientific and technological successes in China were in their infancy,and to provide the reader with insight on how various challenges were overc...This article aims to analyze the so-called“starting point”when modern scientific and technological successes in China were in their infancy,and to provide the reader with insight on how various challenges were overcome in their development.The period under review is 1949–1955.The information about this period was obtained from Soviet archives and special literature.The first part of the article describes the state of affairs in the People’s Republic of China(PRC)in the early years of its formation,focusing on education,science,industry(including military),communications,and rail transport.The second part turns to the Soviet specialists working in the PRC during these years,focusing on their profession,number,cities of residence and living conditions.Issues regarding Chinese specialists’internship in the Union of Soviet Socialist Republics(USSR)are also touched upon.The article selects several lesserknown areas in which professional competencies were established in this very weak post-war country to discover the origins of the most important science and technology in the contemporary PRC,thereby contributing to readers’understanding of the initial conditions for the development of science and technology in China.展开更多
This paper design the agricultural products circulation information system based on Internet of things, the information system in the agficultttral products circulation creative use Internet of things technology, to r...This paper design the agricultural products circulation information system based on Internet of things, the information system in the agficultttral products circulation creative use Internet of things technology, to realize the a greater extent information sharing. The system adopts the design idea of the software SOA, it emphasizes the independence of service module. I hope this system can provide some reference to the agricultural products circulation information.展开更多
Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (...Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (SPR) chip. By using this chip in a homemade SPR immunosensor, low molecular weight compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) can be detected at a low level of 0.01 ng/mL. There is a good linear relationship(R2 =0.943 1) between the results of SPR biosensor and enzyme-linked immunosorbent assay(ELISA).展开更多
A series of 4,4'-disubstituted-[2,2']-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- t...A series of 4,4'-disubstituted-[2,2']-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- thesized and employed in the copolymerization of carbon monoxide (CO) and styrene. The available bipyridine and its derivatives were coordinated with palladium ( II ) acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of t3C NMR, FTIR, differential scanning calo- rimetry (DSC) and element analysis techniques concerning its structure and thermal performance. The effect of dif- ferent electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of co- polymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composi- tion, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2'-bipyridine ligand(l 356 gSTCO/(gPd · h)), when the molecular weight and polydispersity index of the polyketone are Mn = 8 502, Mw = 1 3440 and Mw/Mn = 1.581, respectively.展开更多
文摘Enhancing catalytic activity of multi-enzyme in vitro through substrate channeling effect is promis-ing yet challenging.Herein,conjugated microporous polymers(CMPs)-scaffolded integrated en-zyme cascade systems(I-ECSs)are constructed through co-entrapping glucose oxidase(GOx)and horseradish peroxidase(HRP),in which hydrogen peroxide(H_(2)O_(2))is the intermediate product.The interplay of low-resistance mass transfer pathway and appropriate pore wall-H_(2)O_(2)interactions facilitates the directed transfer of H_(2)O_(2),resulting in 2.4-fold and 5.0-fold elevation in catalytic activ-ity compared to free ECSs and separated ECSs,respectively.The substrate channeling effect could be regulated by altering the mass ratio of GOx to HRP.Besides,I-ECSs demonstrate excellent stabili-ties in harsh environments and multiple recycling.
基金Project(2011JQ028)supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(2008SK3114,2010SK3113)supported by Hunan Provincial Science&Technology Plan,China+2 种基金Project(B2007086)supported by Science&Research Funds of Hunan Health Department,ChinaProject(12JJ5057)supported by Natural Science Foundation of Hunan Province,ChinaProjects(XCX1119,XCX12073)supported by University Students Innovative Experiment Plan Project of Hunan Agricultural University,China
文摘Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid (FA) ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging (MRI) target detection and magnetic hyperthermia.
文摘[Objective] The paper was to compare the quality of apple vinegars prepared by different methods and screen an optimum brewing method for apple vinegar production. [Methed] The quality of apple vinegar brewed by three traditional brewing methods and a new method developed by our previous work was analyzed. Three traditional methods were solid state fermentation (SSF), liquid state fermentation (LSF) and immobilized microorganism fermentation (IMF), and the new method was multi-microorganisms co-immobilization technology(MMCT), which used co-immobilized beads of ethanol-producing yeast, aroma-improving yeast and lactic acid bacteria (with a ratio of 6:3:1) for alcoholic fermentation and then used immobilized acetic acid bacteria for vinegar fermentation. [Result] The general quality of apple vinegar brewed by MMCT was superior to the others. Its total acidity reached to 3.845 g/100 ml, unvolatile acidity was about 0.600 g/100 ml, amino-nitrogen was higher than 0.510 g/100 ml, and the composing of flavor compounds was almost similar to that of SSF brewed apple vinegar. [Conclusion] The MMCT method was proven to be the optimum one for high quality apple vinegar brewing and might be widely used in the future.
文摘An electromechanical nonlinear model of rotor system of electric machine is built.Respondance curves in parameter excited nonlinear vibration of this system caused by electromagnetic forces are investigated.Further more,the analysis reveals the effects of various electromagnetic and mechanical parameters on resonances, and some valuable results are obtained.The analytical result of this paper provides electric machine with the condition of 1/2 subharmonic resonance under the electromechanical electromagnetic forces.Electromagnetic forces apparently affect the stability zone, and both linear term and nonlinear term can excite parametric resonance.The revealed dynamic phenomena provide some new theories and active methods for the fault recognition of electric machine and the defination of stability range,and the theoretical bases for qualitatively controlling the stable operating state of rotors.
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars of MOE and the Natural Scientific Foundation of Anhui Education Department (2003kj052)
文摘The recent progress of non-covalent associative structure of coal, and the mechanisms of the CS2/NMP (1:1 by volume) mixed solvent and the additive addition enhancing the extraction yield of coals were reviewed, and the aggregation behavior of coal in solid and solution states were presented, and the aggregation behavior of coal in solid and solution states were introduced in this paper. Coal extraction and swelling in organic solvents at room temperature were the most useful methods to understand the associative structure of coal. CS2/NMP (1:1 by volume) is a unique solvent to give high extraction yields for some bituminous coals. Some additives can dissociate the stronger interactions among coal molecules and enhance the extraction yields of coal in the mixed solvent.
文摘The time has come for the constitution of the Association of Southeast Asian Nations (ASEAN) economic community and many facts have been analyzed regarding this topic. This paper presents the results of the statistical analysis applied to several economic parameters which firstly show how their integration pattern adjusts with a considerable good fitting to the optimum currency area model and to its extended version by Behrens; and secondly how the 10 members of this group are moving at relatively same speed in spite of their differences, that are also inferred for ranging.
基金Supported by Natural Science Foundation of China under Grant No. 10975079the Natural Science Foundation of Ningbo under Grant No. 2008A61003 K.C. Wong Magna Fund in Ningbo University of China
文摘The effect of the correlation of two dichotomous noises on stochastic resonance is investigated for a linear stochastic system subject to a periodic oscillatory signal. It is found that, the correlation between the two dichotomous noises can not only affect the appearance of the stochastic resonance phenomenon, but also the distinctness of the stochastic resonance phenomenon. There is an optimal value of the correlation, at which the stochastic resonance phenomenon is most distinct. In addition, the correlation between the two dichotomous noises can also cause the movement of the peak of stochastic resonance. Finally, two stochastic resonances caused by two correlated multiplicative dichotomous noises can be found in this system.
文摘In order to deal with the complex association relationships between classes in an object-oriented software system,a novel approach for identifying refactoring opportunities is proposed.The approach can be used to detect complex and duplicated many-to-many association relationships in source code,and to provide guidance for further refactoring.In the approach,source code is first transformed to an abstract syntax tree from which all data members of each class are extracted,then each class is characterized in connection with a set of association classes saving its data members.Next,classes in common associations are obtained by comparing different association classes sets in integrated analysis.Finally,on condition of pre-defined thresholds,all class sets in candidate for refactoring and their common association classes are saved and exported.This approach is tested on 4 projects.The results show that the precision is over 96%when the threshold is 3,and 100%when the threshold is 4.Meanwhile,this approach has good execution efficiency as the execution time taken for a project with more than 500 classes is less than 4 s,which also indicates that it can be applied to projects of different scales to identify their refactoring opportunities effectively.
基金the financial support from the SINOPEC (ST 13028)
文摘In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil samples. The preheating temperature had a great influence on the viscosity of oil samples and the resolution of spectral analysis. The repeatability of spectral measurements was impacted by the metal and wax content of the oil samples. For the case of high wax content oils, the wax species began to crystallize in the course of determination that could affect the repeatability of spectral measurements. These factors have evidenced why the preheating devices and filter unit are necessary when low field NMR system is used in the online analysis process. The investigation is very important for the on-line application of the low field NMR.
文摘Two kinds of St/DVB copolymer beeds containing (1 - pyrenyl) formyl and(1 -pyrenyl) methyl groups respectively have been synthesized by both functionalization and copolymerization. The fluorescence spectra of the swollen polymers synthesized are similar in shape to those of the corresponding model compounds, whilethe intensity ratio of excimer to monomer shows clear dependence on the contents ofthe pyrene groups.
基金This work was supported by the National Natural Science Foundation of China (No.21273211, No.21573208), USTC-NSRL Association Foundation (No.NSRLLHJJ(14-15-012), and the Supercomputation Center of USTC.
文摘The IR absorption, visible excited normal Raman, and UV-excited near-resonant Raman (UVRR) spectra of 1,1'-binaphthyl-2,2'-diamine (BINAM) were measured and analyzed. Density functional theory calculations were carried out to investigate its vibrational frequencies, infrared absorption, normal Raman, and near-resonance Raman intensities. The observed Raman and IR bands of BINAM were assigned with respect to the local vibrations of substituted 2-naphthylamine. Several Raman bands of BINAM were found selectively enhanced in the UVRR in comparison with the normal Raman spectrum. Possible excited state geometry distortion was discussed based on the resonance Raman intensity analysis.
文摘This paper summarizes the results of the international questionnaire survey which took place at the start of 2013 in order to examine, judge, and compare the implemented concept and procedures of human resource management in the questioned building companies operating in the Visegrad Four countries (the Czech Republic, Hungary, Poland, and the Slovak Republic) and the Federal Republic of Germany, and proposes an optimal approach to human resource management in the context of the current and expected economic development. The questionnaire survey was based on the assumption that effective human resource management is a condition of the successful function of each building company and that human resource management is that area of management which distinguishes the successful building companies from the unsuccessful ones. In total, 202 companies from the Czech Republic, 105 companies from Hungary, 100 companies from Poland, 102 companies from the Slovak Republic, and 99 companies from the Federal Republic of Germany took part in the questionnaire survey. The results of the questionnaire survey showed that among the building companies questioned in individual countries, there was no substantial difference in the overall concept and in the partial procedures of human resource management. The implemented concept and procedures in the questioned building companies show significant merits and surprising shortcomings, whereas it is difficult to prove an unequivocal connection between the efficiency of human resource management and the success of building companies. This relationship is determined by a series of other political, economic, legal, social, cultural, technical, demographic, and natural effects which are not related to the efficiency of human resource management or to the performance of the workforce of building companies.
文摘This article aims to analyze the so-called“starting point”when modern scientific and technological successes in China were in their infancy,and to provide the reader with insight on how various challenges were overcome in their development.The period under review is 1949–1955.The information about this period was obtained from Soviet archives and special literature.The first part of the article describes the state of affairs in the People’s Republic of China(PRC)in the early years of its formation,focusing on education,science,industry(including military),communications,and rail transport.The second part turns to the Soviet specialists working in the PRC during these years,focusing on their profession,number,cities of residence and living conditions.Issues regarding Chinese specialists’internship in the Union of Soviet Socialist Republics(USSR)are also touched upon.The article selects several lesserknown areas in which professional competencies were established in this very weak post-war country to discover the origins of the most important science and technology in the contemporary PRC,thereby contributing to readers’understanding of the initial conditions for the development of science and technology in China.
文摘This paper design the agricultural products circulation information system based on Internet of things, the information system in the agficultttral products circulation creative use Internet of things technology, to realize the a greater extent information sharing. The system adopts the design idea of the software SOA, it emphasizes the independence of service module. I hope this system can provide some reference to the agricultural products circulation information.
基金Supported by the National Natural Science Foundation of Tianjin (No. 09JCZDJC25700, 12JCZDJC29600 and KJXH2011-11)
文摘Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (SPR) chip. By using this chip in a homemade SPR immunosensor, low molecular weight compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) can be detected at a low level of 0.01 ng/mL. There is a good linear relationship(R2 =0.943 1) between the results of SPR biosensor and enzyme-linked immunosorbent assay(ELISA).
基金Supported by Tianjin Natural Science Foundation(No.07JCYBJC00600)
文摘A series of 4,4'-disubstituted-[2,2']-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- thesized and employed in the copolymerization of carbon monoxide (CO) and styrene. The available bipyridine and its derivatives were coordinated with palladium ( II ) acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of t3C NMR, FTIR, differential scanning calo- rimetry (DSC) and element analysis techniques concerning its structure and thermal performance. The effect of dif- ferent electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of co- polymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composi- tion, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2'-bipyridine ligand(l 356 gSTCO/(gPd · h)), when the molecular weight and polydispersity index of the polyketone are Mn = 8 502, Mw = 1 3440 and Mw/Mn = 1.581, respectively.