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Existence and Uniqueness of Positive Solutions for Some Singular Boundary Value Problems with Linear functional Boundary Conditions

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Acta Mathematica Sinica,English Series 2011年第10期27卷 2073-2084页

作者： Zeng qin ZHAO fu Shan LI School of Mathematical Sciences Qufu Normal University Qufu 273165 P. R. China

By using the upper and lower solution method and fixed point theory, we investigate some nonlinear singular second-order differential equations with linear functional boundary conditions. The nonlinear term f（t, u） is nonincreasing with respect to u, and only possesses some integrability. We obtain the existence and uniqueness of the C[0, 1] positive solutions as well as the C1 [0, 1] positive solutions.

关键词： Linear functional boundary condition decreasing function positive solution upper and lower solution method fixed point theorem

Stratum energy of coal-bed gas reservoir and their control on the coal-bed gas reservoir formation

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Science China Earth Sciences 2007年第9期50卷 1319-1326页

作者： WU CaiFang qin Yong fu XueHai Department of Earth Resources and Geosciences China University of Mining & Technology Xuzhou 221008 China Department of Earth Resources and Geosciences China University of Mining & Technology Xuzhou 221008 China Department of Earth Resources and Geosciences China University of Mining & Technology Xuzhou 221008 China

Stratum energy of coal-bed gas reservoir, including coal-radix flexibility energy, groundwater flexibility energy and gas flexibility energy (hereinafter "three energy"), depends on the energy homeostasis system, the core process of which is the effective transfer of energy and the geological selective process. Combining with the mechanics experimentations of coal samples, different flexibility energy has been analyzed and researched quantificationally, and a profound discussion to their controls on the coal-bed gas reservoir formation has been made. It is shown that when gas reservoir is surrounded by edge water and bottom water, the deposited energy in the early phase of forming gas reservoir is mostly coal-radix and gas flexibility energy, but the effect of groundwater flexibility energy increases while water-body increases. The deposited energy in the middle and later phase of forming gas reser voir is mostly gas flexibility energy, which is greater than 80% of all deposited energy. In the whole process, larger groundwater body exerts greater influences on gas accumulation. The paper indicated that higher stratum energy is more propitious to forming coal-bed gas reservoir. And higher coal-radix flexibility energy and gas flexibility energy are more propitious to higher yield of gas reservoirs, while higher groundwater flexibility energy is more propitious to stable yield of gas reservoirs. Therefore, the key to evaluating the coal-bed gas reservoir formation is the stratum energy of coal-bed gas reservoir.

关键词： coal-bed reservoir, flexibility energy, coal-radix flexibility energy, groundwater flexibility energy, gas flexibility energy, coal-bed gas reservoir formation

Study on the Free-Surface Flow of Silicon Melt in the Crucible

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Rare Metals 1989年第1期9卷 39-44页

作者： Li, Yingchun Wan, Qun fu, qin General Research Inst for Non-ferrous Metals China

The flow of a free-surface layer melt in a crucible has been studied by observing the movement of the particle on the free-surface of a silicon melt. A new view on the transportation of impurities in the melt is presented. The experimental results verify the effect of the free-surface layer melt's flow on the distribution of impurities in the as-grown crystal.

关键词： Crystals Growing

Oxygen Incorporation in Czochralski Growth of Silicon under a Horizontal Magnetic Field

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Rare Metals 1990年第1期10卷 52-57页

作者： Wang, Tihu Li, Yingchun qin, fu General Research Inst for Non-ferrous Metals China

A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field (HMCZ) is proposed. Oxygen depleted surface melt, driven to the growth interface by the thermal Marangoni flow, determines oxygen concentration in the grown crystals. Systematic study was carried out to investigate effects of growth parameters on oxygen incorporation into crystals.

关键词： Crystals Defects Flow of Fluids Turbulent Liquid Metals Magnetic Field Effects Oxygen Transport Properties Silicon and Alloys Molten

Feedback control for a class of second order hyperbolic distributed parameter systems

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Science China(Information Sciences) 2016年第9期59卷 156-164页

作者： qin fu Weiguo GU Panpan GU Jianrong WU School of Mathematics and Physics Suzhou University of Science and Technology

This paper deals with the problem of state feedback control for a class of the distributed parameter systems with the disturbance term. And the considered distributed parameter systems are composed of the second order hyperbolic partial differential equations. Two different classes of restrictions on the disturbance term are given, one is that the disturbance term satisfies the linear growth constraint condition to the state variables of the system, and the other is that the disturbance term obeys the bound constraint under the significance of L2. Based on a variable structure method, the state feedback controllers are obtained by means of constructing appropriate Lyapunov functional. The closed-loop systems are globally asymptotically stable on W1,2（0, 1） × L2（0, 1） space under the effect of the state feedback control laws. Simulation results illustrate the effectiveness of the proposed method.

关键词： state feedback globally asymptotically stable second order hyperbolic distributed parameter sys tems variable structure method Lyapunov functional

Covalent electron density analysis and surface energy calculation of gold with the empirical electron surface model

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International Journal of Minerals,Metallurgy and Materials 2011年第6期18卷 676-682页

作者： Bao-qin fu Zhi-lin Li Wei Liu College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Laboratory of Advanced Materials Department of Material Science and Engineering Tsinghua University Beijing 100084 China

Based on the empirical electron surface model （EESM）,the covalent electron density of dangling bonds （CEDDB） was calculated for various crystal planes of gold,and the surface energy was calculated *** results show that CEDDB has a great influence on the surface energy of various index surfaces and the anisotropy of the *** calculated surface energy is in agreement with experimental and other theoretical *** calculated surface energy of the close-packed （111） surface has the lowest surface energy,which agrees with the theoretical ***,it is found that the spatial distribution of covalent bonds has a great influence on the surface energy of various index ***,CEDDB should be a suitable parameter to describe and quantify the dangling bonds and surface energy of various crystal surfaces.

关键词： surface energy dangling bonds covalent bonds electron density gold

Epstein-Barr virus interactions with the Bcl-2 protein family and apoptosis in human tumor cells

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第1期14卷 8-24页

作者： qin fu Chen HE Zheng-rong MAO Department of Pathology and Pathophysiology School of Medicine Zhejiang University Hangzhou 310058 China

Epstein-Barr virus(EBV),a human gammaherpesvirus carried by more than 90% of the world's population,is associated with malignant tumors such as Burkitt's lymphoma(BL),Hodgkin lymphoma,post-transplant lymphoma,extra-nodal natural killer/T cell lymphoma,and nasopharyngeal and gastric carcinomas in immune-compromised *** the process of infection,EBV faces challenges:the host cell environment is harsh,and the survival and apoptosis of host cells are precisely *** when host cells receive sufficient survival signals may they *** establish efficiently a lytic or long-term latent infection,EBV must escape the host cell immunologic mechanism and resist host cell apoptosis by interfering with multiple signaling *** review details the apoptotic pathway disrupted by EBV in EBV-infected cells and describes the interactions of EBV gene products with host cellular factors as well as the function of these factors,which decide the fate of the host *** relationships between other EBV-encoded genes and proteins of the B-cell leukemia/lymphoma(Bcl) family are ***,EBV seems to contribute to establishing its own latency and the formation of tumors by modifying events that impact cell survival and proliferation as well as the immune response of the infected *** discuss potential therapeutic drugs to provide a foundation for further studies of tumor pathogenesis aimed at exploiting novel therapeutic strategies for EBV-associated diseases.

关键词： Epstein-Barr virus Bcl family members Apoptosis Drugs therapy

The impact of political connections on firm pollution: New evidence based on heterogeneous environmental regulation

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Petroleum Science 2023年第1期20卷 636-647页

作者： Zong-Run Wang Hai-qin fu Xiao-Hang Ren School of Business Central South UniversityChangsha410083China

Increasing attention has been focused on the extent to which corporate political connections influence the growing pollution due to the rapid growth in the popularity of firm pollution in developing *** adopt a static threshold regression model to investigate the effects of heterogeneous environmental regulation on political connections and firm pollution based on the panel data from China’s A-share listed companies from 2012 to *** empirical results show a non-linear relationship between the degree of political connection of listed company executives and the level of firm *** the relationship between the two roughly presents a U-shaped relationship under the action of the marketincentive environmental regulation ***,it roughly presents an inverted N-shaped relationship under the action of the command-control environmental regulation ***,the group test results show that the existence of regional and ownership heterogeneity causes certain differences in the environmental behaviour of politically connected *** findings indicate that diverse environmental regulations are needed to promote sustainable green development and to further expand the theoretical and practical exploration of political connections on firm pollution.

关键词： Political connections Firm pollution Market-incentive environmental regulation Command-control environmental regulation Threshold model

Influence of TiO2 on the melting property and viscosity of Cr-containing high-Ti melting slag

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International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 310-318页

作者： Jing Ma Gui-qin fu Wei Li Miao-yong Zhu School of Metallurgy Northeastern University

A study on the melting and viscosity properties of the chromium-containing high-titanium melting slag(CaO–SiO2–MgO–Al2O3–TiO2–Cr2O3) with TiO2 contents ranging from 38.63 wt% to 42.63 wt% was conducted. The melting properties were investigated with a meltingpoint apparatus, and viscosity was measured using the rotating cylinder method. The FactSage 7.1 software and X-ray diffraction, in combination with scanning electron microscopy–energy-dispersive spectroscopy(SEM–EDS), were used to characterize the phase equilibrium and microstructure of chromium-containing high-titanium melting slags. The results indicated that an increase in the TiO2 content led to a decrease in the viscosity of the chromium-containing high-titanium melting slag. In addition, the softening temperature, hemispheric temperature, and flowing temperature decreased with increasing TiO2 content. The amount of crystallized anosovite and sphene phases gradually increased with increasing TiO2 content, whereas the amount of perovskite phase decreased. SEM observations revealed that the distribution of the anosovite phase was dominantly influenced by TiO2.

关键词： titanium dioxide Cr-containing high-titanium melting slag melting property viscosity vanadium titanomagnetite