根据美国Second Life Library 2.0虚拟社区的建设现状,分析图书馆虚拟社区的营销模式,认为虚拟社区改变了用户被动服务的地位,获得了主动权。对此,图书馆需采用聚众为媒的策略,为虚拟社区中的用户营造良好的使用体验,引导用户成为创建...根据美国Second Life Library 2.0虚拟社区的建设现状,分析图书馆虚拟社区的营销模式,认为虚拟社区改变了用户被动服务的地位,获得了主动权。对此,图书馆需采用聚众为媒的策略,为虚拟社区中的用户营造良好的使用体验,引导用户成为创建服务的合作者和品牌传播的中间人。展开更多
Silica glasses doped with Bi2S3 microcystallite was prepared by the sol-gel process. Photoinduced second harmonic generation (SHG) was observed in the glass when it was irradiated with intense 1.06 mum and frequency d...Silica glasses doped with Bi2S3 microcystallite was prepared by the sol-gel process. Photoinduced second harmonic generation (SHG) was observed in the glass when it was irradiated with intense 1.06 mum and frequency doubled laser beams from a mode-locked Nd: YAG laser. It was found that the signal intensity increased with the irradiating time and approached a saturation gradually. The effect may be explained reasonably by the DC field model.展开更多
We introduce the higher-order type 2 Bernoulli numbers and polynomials of the second kind.In this paper,we investigate some identities and properties for them in connection with central factorial numbers of the second...We introduce the higher-order type 2 Bernoulli numbers and polynomials of the second kind.In this paper,we investigate some identities and properties for them in connection with central factorial numbers of the second kind and the higher-order type 2 Bernoulli polynomials.We give some relations between the higher-order type 2 Bernoulli numbers of the second kind and their conjugates.展开更多
A key issue of practical importance in the two-dimensional (2-D) discrete system is stability analysis. Linear state-space models describing 2-D discrete systems have been proposed by several researchers. A popular mo...A key issue of practical importance in the two-dimensional (2-D) discrete system is stability analysis. Linear state-space models describing 2-D discrete systems have been proposed by several researchers. A popular model, called Forna- sini-Marchesini (FM) second model was proposed by Fornasini and Marchesini in 1978. The aim of this paper is to present a survey of the existing literature on the stability of FM second model.展开更多
With the pulsed laser deposition （PLD） method, amorphous 80GeS2-15Ga2S3-5CdS chalcogenide film was deposited on glassy substrate. Obvious second harmonic generation （SHG） was observed in the ultraviolet （UV）-pol...With the pulsed laser deposition （PLD） method, amorphous 80GeS2-15Ga2S3-5CdS chalcogenide film was deposited on glassy substrate. Obvious second harmonic generation （SHG） was observed in the ultraviolet （UV）-polarized film and the SHG intensity increased with the increase in single pulse energy and irradiation time. Through Raman spectra and transmission spectra, the mechanism of SHG was studied. The experimental results demonstrated that effective electron traps and hole traps were generated in the UV- polarized film. The energy of electrons and holes was using up due to the collision with other particles and crystal fields during their movement and finally they were captured by the traps and fixed, which made the electric charge distribution nonuniform in the film and destroyed the spatial isotropy. In the meantime, the center of positive and negative charges separated and a built-in electric field was formed which generated the optical second-order nonlinearity of the film.展开更多
The 2nd International Symposium on Refrac-toties jointly organized by the Chinese Ceramic So-ciety and the Chinese Society for Metals was heldin Beijing, China, On October 30-Novemeber 2,1992. The Technical Associatio...The 2nd International Symposium on Refrac-toties jointly organized by the Chinese Ceramic So-ciety and the Chinese Society for Metals was heldin Beijing, China, On October 30-Novemeber 2,1992. The Technical Association of Refractories,Japan, the American Ceramic Society, the Refrac-tories Association of Great Britain, the GermanRefractories Association, the Australian Ceramic展开更多
Effects of addition of H2 gas in air DB discharge on its optical and electrical characteristics have been studied. Optical emission spectroscopy is used to investigate the effect of hydrogen admixing on the emission i...Effects of addition of H2 gas in air DB discharge on its optical and electrical characteristics have been studied. Optical emission spectroscopy is used to investigate the effect of hydrogen admixing on the emission intensity of the nitrogen second positive systems (300 - 420 nm) and the relative population density of states. An obvious decaying of the emission intensity of the nitrogen second positive bands with the introduction of H2 has been observed. It has been concluded that quenching of the nitrogen excited state is the responsible reason of this decaying. Mechanisms of excitation and ionization processes of nitrogen molecules in this mixture have been studied. Processes which are responsible for the decaying of the population density of have been reported. Addition of H2 to air improves the electrical characteristics of the DB discharge. An abrupt increasing in the electron density, reached about thirty fold at H2 flow rate of 3 L/min, as a result of increasing the ionization processes has been reported. The breakdown voltage of the discharge decreased from 1.87 kV to about 1.25 kV by the addition of H2 at flow rate of 3 L/min.展开更多
Sufficient conditions for the existence and uniqueness of second boundary value problems of two kinds of even order nonlinear differential equations are obtained. The proofs are based on the lemma on bilinear form, de...Sufficient conditions for the existence and uniqueness of second boundary value problems of two kinds of even order nonlinear differential equations are obtained. The proofs are based on the lemma on bilinear form, developed by A.C.Lazer, Schauder fixed point theorem and the Leray-Schauder degree theory, respectively.展开更多
In order to promote the activeness and initiative of learners and allow them to take theirlearning advantages,a teacher should be fully aware of the psychological process and models ofL2L．For no matter how well learn...In order to promote the activeness and initiative of learners and allow them to take theirlearning advantages,a teacher should be fully aware of the psychological process and models ofL2L．For no matter how well learners can command a language,their subjective incentives play adecisive role,that is the case particularly for non—Eniglish majors,who are always exposed tocrowded,serious and teacher—centred learning contexts.展开更多
文摘Silica glasses doped with Bi2S3 microcystallite was prepared by the sol-gel process. Photoinduced second harmonic generation (SHG) was observed in the glass when it was irradiated with intense 1.06 mum and frequency doubled laser beams from a mode-locked Nd: YAG laser. It was found that the signal intensity increased with the irradiating time and approached a saturation gradually. The effect may be explained reasonably by the DC field model.
基金This work was supported by the National Research Foundation of Korea(NRF)Grant Funded by the Korea Government(No.2020R1F1A1A01071564).
文摘We introduce the higher-order type 2 Bernoulli numbers and polynomials of the second kind.In this paper,we investigate some identities and properties for them in connection with central factorial numbers of the second kind and the higher-order type 2 Bernoulli polynomials.We give some relations between the higher-order type 2 Bernoulli numbers of the second kind and their conjugates.
文摘A key issue of practical importance in the two-dimensional (2-D) discrete system is stability analysis. Linear state-space models describing 2-D discrete systems have been proposed by several researchers. A popular model, called Forna- sini-Marchesini (FM) second model was proposed by Fornasini and Marchesini in 1978. The aim of this paper is to present a survey of the existing literature on the stability of FM second model.
基金Funded by the National Natural Science Foundaition of China(Nos.51172169 and 61177084),NCET\(NCET-11-0687)the Fundamental Research Funds for the Central Universities(Wuhan University of Technology)
文摘With the pulsed laser deposition （PLD） method, amorphous 80GeS2-15Ga2S3-5CdS chalcogenide film was deposited on glassy substrate. Obvious second harmonic generation （SHG） was observed in the ultraviolet （UV）-polarized film and the SHG intensity increased with the increase in single pulse energy and irradiation time. Through Raman spectra and transmission spectra, the mechanism of SHG was studied. The experimental results demonstrated that effective electron traps and hole traps were generated in the UV- polarized film. The energy of electrons and holes was using up due to the collision with other particles and crystal fields during their movement and finally they were captured by the traps and fixed, which made the electric charge distribution nonuniform in the film and destroyed the spatial isotropy. In the meantime, the center of positive and negative charges separated and a built-in electric field was formed which generated the optical second-order nonlinearity of the film.
文摘The 2nd International Symposium on Refrac-toties jointly organized by the Chinese Ceramic So-ciety and the Chinese Society for Metals was heldin Beijing, China, On October 30-Novemeber 2,1992. The Technical Association of Refractories,Japan, the American Ceramic Society, the Refrac-tories Association of Great Britain, the GermanRefractories Association, the Australian Ceramic
文摘Effects of addition of H2 gas in air DB discharge on its optical and electrical characteristics have been studied. Optical emission spectroscopy is used to investigate the effect of hydrogen admixing on the emission intensity of the nitrogen second positive systems (300 - 420 nm) and the relative population density of states. An obvious decaying of the emission intensity of the nitrogen second positive bands with the introduction of H2 has been observed. It has been concluded that quenching of the nitrogen excited state is the responsible reason of this decaying. Mechanisms of excitation and ionization processes of nitrogen molecules in this mixture have been studied. Processes which are responsible for the decaying of the population density of have been reported. Addition of H2 to air improves the electrical characteristics of the DB discharge. An abrupt increasing in the electron density, reached about thirty fold at H2 flow rate of 3 L/min, as a result of increasing the ionization processes has been reported. The breakdown voltage of the discharge decreased from 1.87 kV to about 1.25 kV by the addition of H2 at flow rate of 3 L/min.
文摘Sufficient conditions for the existence and uniqueness of second boundary value problems of two kinds of even order nonlinear differential equations are obtained. The proofs are based on the lemma on bilinear form, developed by A.C.Lazer, Schauder fixed point theorem and the Leray-Schauder degree theory, respectively.
文摘In order to promote the activeness and initiative of learners and allow them to take theirlearning advantages,a teacher should be fully aware of the psychological process and models ofL2L．For no matter how well learners can command a language,their subjective incentives play adecisive role,that is the case particularly for non—Eniglish majors,who are always exposed tocrowded,serious and teacher—centred learning contexts.
