本文较为详细地介绍了自Van der Waals状态方程以来所发展的若干典型的状态方程,并对各类型的状态方程进行了评价。但到目前为止还没有一种状态方程能对任何物质在很大范围内都是通用的。特别对量子流体及某些强极性物质,任何状态方程...本文较为详细地介绍了自Van der Waals状态方程以来所发展的若干典型的状态方程,并对各类型的状态方程进行了评价。但到目前为止还没有一种状态方程能对任何物质在很大范围内都是通用的。特别对量子流体及某些强极性物质,任何状态方程都还有困难。当前的办法仍是将若干类状态方程同时并用,在不同场合选择最合适的方程使用。因此本文对于状态方程的详细的综述可以为工程设计及从事这方面研究的人员提供有价值的参考。展开更多
In this paper we made a thorough and system- atic expatiation of the definition,connotation and composition of bio-manufacture.Based on the dif- ferent development stages and process of bioengi- neering,its main resea...In this paper we made a thorough and system- atic expatiation of the definition,connotation and composition of bio-manufacture.Based on the dif- ferent development stages and process of bioengi- neering,its main research direction and correspond- ing researches were reviewed.Furthermore,from the viewpoint of disciplinary crossing,integration and development,the main technological develop- ment direction of bio-engineering in the coming years was pointed out.展开更多
Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.De...Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.Descriptors including global softness,Fukui function,local softness and local mulliken charge were calculated at SVWN/DN~* level of DFT with PC Spartan Pro.Nucleophilicity and basicity of 28 selected compounds were classified based on intensity.BP algorithm of artificial neural network(ANN) was employed to study the relationship between the descriptors and nucleophilicity/basicity.Cross-validation was carried out to avoid the over-fitting in training of ANN.A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons.The results show that the prediction based on the network matches with the experimental results well.The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity.The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.展开更多
Using an adaptive split-step Fourier method,the coupled nonlinear Schrdinger equations have been numerically solved in this paper.The nonlinear propagation of an ultrashort optical pulse in the birefringent photonic c...Using an adaptive split-step Fourier method,the coupled nonlinear Schrdinger equations have been numerically solved in this paper.The nonlinear propagation of an ultrashort optical pulse in the birefringent photonic crystal fibers is investigated numerically.It is found that the phenomenon of pulse trapping occurs when the incident pulse is deviating from the principal axis of the fiber with some angle.Owing to the birefringence effect,the incident pulse can be regarded as two orthogonal polarized pulses.The phenomenon of pulse trapping occurs because of the cross phase modulation(XPM) between the two components.As a result,the bandwidth of the supercontinuum(SC) decreases compared with the case that the incident pulse is input along the principal axis.When the polarization direction of the incident pulse is parallel to the fast axis,the bandwidth of the supercontinuum is maximal.展开更多
文摘本文较为详细地介绍了自Van der Waals状态方程以来所发展的若干典型的状态方程,并对各类型的状态方程进行了评价。但到目前为止还没有一种状态方程能对任何物质在很大范围内都是通用的。特别对量子流体及某些强极性物质,任何状态方程都还有困难。当前的办法仍是将若干类状态方程同时并用,在不同场合选择最合适的方程使用。因此本文对于状态方程的详细的综述可以为工程设计及从事这方面研究的人员提供有价值的参考。
文摘In this paper we made a thorough and system- atic expatiation of the definition,connotation and composition of bio-manufacture.Based on the dif- ferent development stages and process of bioengi- neering,its main research direction and correspond- ing researches were reviewed.Furthermore,from the viewpoint of disciplinary crossing,integration and development,the main technological develop- ment direction of bio-engineering in the coming years was pointed out.
基金National Science & Technology Major Project of China(Grant No.2009ZX09501-002)National Natural Science Foundation of China(Grant No.20802006).
文摘Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.Descriptors including global softness,Fukui function,local softness and local mulliken charge were calculated at SVWN/DN~* level of DFT with PC Spartan Pro.Nucleophilicity and basicity of 28 selected compounds were classified based on intensity.BP algorithm of artificial neural network(ANN) was employed to study the relationship between the descriptors and nucleophilicity/basicity.Cross-validation was carried out to avoid the over-fitting in training of ANN.A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons.The results show that the prediction based on the network matches with the experimental results well.The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity.The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.
基金supported by the National Natural Science Foundation of China (No.10874145)the Natural Science Foundation of Hebei Province of China (No.F2009000481)the China Postdoctoral Science Foundation (No.20080440014)
文摘Using an adaptive split-step Fourier method,the coupled nonlinear Schrdinger equations have been numerically solved in this paper.The nonlinear propagation of an ultrashort optical pulse in the birefringent photonic crystal fibers is investigated numerically.It is found that the phenomenon of pulse trapping occurs when the incident pulse is deviating from the principal axis of the fiber with some angle.Owing to the birefringence effect,the incident pulse can be regarded as two orthogonal polarized pulses.The phenomenon of pulse trapping occurs because of the cross phase modulation(XPM) between the two components.As a result,the bandwidth of the supercontinuum(SC) decreases compared with the case that the incident pulse is input along the principal axis.When the polarization direction of the incident pulse is parallel to the fast axis,the bandwidth of the supercontinuum is maximal.
