检索结果-南通市图书馆

Minority population and sustainable development in mountain regions a case study of the Tibetan inhabited region in sichuan, china

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical sciences 1998年第4期8卷 12-20页

作者： CHEN Yong HE Ginxi Institute of Population Research, sichuan university, chengdu 610064, china AI Nanshan Institute of Environmental {3. & engineering, sichuan university, chengdu 610064, china

china boasts 56 nationalities who are mostly inhabited in the sparsely populated mountain regions in West china. Like many other places in the Han nationality distributed regions, minority nationality inhabited regions are also facing the challenge of sustainable development in terms of both natural and human factors. Taking the Tibetan inhabited regions (TIR) in sichuan Province as a case, this paper points out some major problems in the process of economic development in perspective of sustainability and leaves some hints for development strategies. While natural conditions such as geological instability are playing a major role to the environmental degradation, human activities and improper use of resources might constitute an important agent in the environmental deterioration. In order to promote local economic development and improve people’s living standard, sustainable planning is expected to be made and people’s awareness of sustainability should be strengthened.

关键词： Tibetan inhabited region (TIR) minority population sustainable development development strategy.

Research on Water Resources Conservation of Mountain River Based on the Concept of Region Partition

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain science 2011年第4期8卷 582-591页

作者： LIU Yubang TAO Qingyu LIANG Chuan WU Yong State Key Laboratory of Geohazard Prevention and Geoenvironment Protection chengdu university of Technology Chengdu 61o059 China State Key Laboratory of Hydraulics and Mountain River engineering College of Water Resource & Hydropower Sichuan University Chengdu 61oo65 China Academic Journal Center of chengdu university of Technology Chengdu 61oo59 China

Presently concepts and methods related to water resources conservation of mountain rivers are seriously insufficient,and its level is far from being adaptable to the development of a harmonious *** mountain ecosystems play a key role in water resources conservation of mountain rivers,and the characteristics of mountain ecosystems and hydrologic features of mountain river follow strong temporal and spatial distribution,partition theory can be applied to the water resources conservation of mountain *** theory observes the following partition principles:regional relativity,spatial continuity,integralcounty,meeting management needs,hierarchical principle,and comparability *** it lays equal emphasis on both water resources conservation and environmental protection,on both water quality conservation and water quantity protection,on the combination of water features,water cycle and water *** the partition methods,index method and map superposition method will be applied in region *** example of region partition of water resources conservation in the upper reaches of the Yangtze River shows that the partition theory is practicable in water resources conservation of mountain rivers,and it provides a platform for future study in water resources conservation.

关键词： Water resources conservation Mountain river Region partition Mountain ecosystems

Two-step Synthesis of TiC_(0.7)N_(0.3.@WC-MoC_2 Core-shell Microspheres and Fabrication of TiC_(0.7)N_(0.3.@WC-MoC_2-based Cermets by SPS

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials science) 2011年第4期26卷 710-714页

作者：俞海军刘颖 School of Materials science and engineering Sichuan University

The precursor with TiC0.7N0.3.WO3.MO3.microspheres were prepared by a novel method from the WO3.MoO3.sol dipping. Subsequently, TiC0.7N0.3.WC-MoC2 core-shell structural microspheres were successfully obtained by carburizing the precursor at 900 °C in a flowing mixture of CH4 （20 ml·min-1） and H2 （200 ml·min-1） for 2 h. Then TiC0.7N0.3.WC-MoC2-15Co cermets were prepared utilizing the core-shell powders by spark plasma sintering （SPS）. Powders of the precursors with TiC0.7N0.3.WO3.MO3.microspheres, TiC0.7N0.3.WC-MoC2 microspheres and TiC0.7N0.3.WC-MoC2-15Co cermets were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The obtained TiC0.7N0.3.WC-MoC2 microspheres have a dense WC-MoC2 coatings shell. The thickness of the shell could be easily controlled by adjusting the number of sol dipping cycles. It was found that the TiC0.7N0.3.WC-MoC2 microspheres were more beneficial to fabricate the ＂core-rim＂ structures by SPS.

关键词： core-shell structure spark plasma sintering (SPS) microstructure fabrication

TRANSIENT QUEUE SIZE DISTRIBUTION SOLUTION OF GEOM/G/1 QUEUE WITH FEEDBACK-A RECURSIVE METHOD

在线全文

学校读者我要写书评

暂无评论

Journal of Systems science & Complexity 2009年第2期22卷 303-312页

作者： Chuanyi LUO Yinghui TANG Cailiang LI department of Economic Mathematics Southwestern University of Finance and Economics Chengdu 610074China. School of Mathematics and Software science Sichuan Normal University Chengdu 610066 China. department of Information and Computer science Chengdu Electron-Mechanical College Chengdu 610031China.

This paper considers the Geom/G/1 queueing model with feedback according to a late arrival system with delayed access （LASDA）. Using recursive method, this paper studies the transient property of the queue size from the initial state N（0＋） = i. Some new results about the recursive expression of the transient queue size distribution at any epoch n＋ and the recursive formulae of the equilibrium distribution are obtained. Furthermore, the recursive formulae of the equilibrium queue size distribution at epoch n-, and n are obtained, too. The important relations between stationary queue size distributions at different epochs are discovered （being different from the relations given in M/G/I queueing system）. The model discussed in this paper can be widely applied in all kinds of communications and computer network.

关键词： Discrete time queue equilibrium distribution feedback recursive expression transient distribution.

Synthesis of potassium hexatitanate whiskers using hydrothermal method

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2009年第1期28卷 24-32页

作者： WANG Ju LI Chun LIANG Bin WANG Xiaoqing College of Chemical engineering Siehuan University Chengdu 610065 China department of Chemistry Tsinghua University Beijing 100084 China

High quality potassium hexatitanate whiskers were hydrothermally synthesized in one step under moderate temperature and pressure conditions. Effects of the titanium source and reaction conditions on the hydrothermal reaction rate, product phase component, and morphology of whiskers were investigated. The results show that the reactivity of hydrated titania, anatase TiO2, and rutile TiO2 with KOH decreases in turn, and with hydrated titania as titanium source, it is difficult to obtain potassium hexatitanate whiskers with good morphology. In contrast, uniform potassium hexatitanate whiskers with a length of 10-20 μm and a diameter of 200-700 nm were obtained using anatase TiO2 as titanium source. The investigation demonstrates that the initial KOH concentration, annealing temperature and time, molar ratio of K2O/TiO2, etc. significantly affect the morphology of the as-synthesized whiskers. The optimized synthesis condition is as follows： anatase as a titanium source 10 wt.% KOH solution; annealing temperature and time of 3.0℃ and 5 h, respectively; K2O/TiO2 molar ratio of 5, etc. A rhombic potassium hexatitanate was prepared under the optimum condition and the whisker grew along the [110] direction. The reaction mechanism was discussed.

关键词： potassium hexatitanate whiskers hydrothermal method synthesis

Thermocontrolling ion permeation through binary component membrane composed of crown ether liquid crystal/PVC

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 1995年第1期13卷 1-9页

作者： QIN, Jun XIE, Ming-Gui JIANG, Qing ZHAO, Hua-Ming department of Chemistry, sichuan university, chengdu, {3. 610064, chinaLIU, Sheng-Chong Analytical and Testing Center, sichuan university, chengdu, {3. 610064, chinaTAO, Chang-Yuan department of Chemistry, Chongqing university, Chongqing, {3. 63.044, china department of Chemistry Sichuan University Chengdu Sichuan 610064 China Analytical and Testing Center Sichuan University Chengdu Sichuan 610064 China department of Chemistry Chongqing University Chongqing Sichuan 630044 China

In view of the nature of orderness in structure and the mesomorphism in property of liquid crystal, the function of which is further exploited by integrating it with the feature of crown ether. The monoarmed crown ether liquid crystals are successfully applied to the imitation of biomembrane transport. Binary component membrane composed of crown ether liquid crystal and PVC was first developed. Such a novel model of biomimetic membrane is capable of imitating ingeniously the thermocontrolling transport of biomembrane, thus the essential function of liquid crystal in membane transport is more fully exploited. It was suggested, consequently, that the molecules of the crown ether liquid crystal could assemble themselves to form ionic channels, as they exist in *** still more significance is that the thermocontrolling transport of ions through the membrane is found to be operative selectively and the permeation of ion is under the direct influence of the thermal turmoil of the crown ether liquid crystal molecules as substantiated by the values of Arrhenius thermodynamic parameters, activation energy, Ea, and logarithmic Arrhenius constant, log A, in ion transport. Based on the aforementioned it is suggested that diffusion of ions is a rate determing step and change of rate of ion transport is varied in different phase. Influence of magnetic field on transport rate is investigated. On basis of above experimental findings, a dynamical equation of ion transportation is established which is applicable for the membrane system in general on one hands and expound the ion transport mechanism through the membrane on the other.

关键词： Crown ether liquid crystal biomimetic membrane thermocontrolling transport binary component membrane.

A New Peptide with Membrane-permeable Function Derived from Human Circadian Proteins

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2004年第9期36卷 629-636页

作者： Tao PENG, Ying-Hui LIU, Chun-Lei YANG, Chao-Min WAN, Yao-Qi WANG, and Zheng-Rong WANG* department of Biomedical engineering, School of Basic Medicine and Forensic, sichuan university, {3. 610041, china department of Biomedical engineering School of Basic Medicine and ForensicSichuan UniversityChengdu 610041China

Basic peptides such as human immunodeficiency virus type 1 (HIV-1) Tat-(48-60) and Droso- phila Antennapedia-(43.58) have been reported to have a membrane permeability and a carrier function for intracellular protein delivery. Based on the fluorescence microscopic observations of the vascular endothelial cells (ECV-3.4) and the primary cultured neuroglial cells, we found that human Clock protein DNA-binding peptide [residue 3.–47, hClock-(3.-47)] had a translocation activity very similar to Tat-(48-60). The cellular uptake of hClock-(3.-47) increases with the increase of incubation time and concentration. The internalization effect at 4 °C was same as that at 3. °C. Internalization of hClock-(3.-47) was saturable and could be inhibited by the excess of the other MPPs. Moreover, The uptake of these peptides were significantly inhibited in the presence of heparan sulfate. These results strongly suggested that the hClock-(3.-47) shared a common or very similar internalization pathway with other MPPs. Furthermore, we injected rat through the common carotid artery with hClock-(3.-47)-FITC peptide, and cryostat sections of the brain were prepared and observed using a fluorescence microscope. Result showed that the peptide had the ability to translocate through the blood-brain barrier. It is promising to provide a new safe carrier for the intracellular and encephalic treatment.

关键词： membrane-permeable peptide (MPP) cell membrane hClock DNA-binding peptide blood-brain barrier

A New Type of Biomimetic Model: Design, Synthesis andCharacteriration of Imidazolium Bis-Estrogen

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第5期8卷 387-388页

作者： Zhi Chang LIU Cheng He ZHOU Ru Gang XIE (department of Chemistry, Faculty of science, sichuan Union {3., chengdu 610064) department of Chemistry Faculty of Science Sichuan Union University Chengdu 610064 China

Two imidazolium bis-estrogens as a new type of biomimetic model, which possesspotential multiple biomimetic functions, were srnthesized in gcod yields by three steps fromestrogen. All new compounds were characterized ... 详细信息

关键词： Design A New Type of Biomimetic Model Synthesis and Characterization of Imidazolium Bis-Estrogen

Polylogarithms and multiple zeta values from free Rota-Baxter algebras

在线全文

学校读者我要写书评

暂无评论

science china Mathematics 2010年第9期53卷 2239-2258页

作者： GUO Li1,2 & ZHANG Bin3.1Center of Mathematical sciences,Zhejiang university,Hangzhou 3.0027,china 2{3. of Mathematics and Computer science,Rutgers university,Newark,NJ 07102,USA 3.angtze Center of Mathematics,sichuan university,chengdu 610064,china Center of Mathematical sciences Zhejiang University department of Mathematics and Computer science Rutgers University Yangtze Center of Mathematics Sichuan University

We show that the shuffle algebras for polylogarithms and regularized MZVs in the sense of Ihara,Kaneko and Zagier are both free commutative nonunitary Rota-Baxter algebras with one *** apply these results to show that the full sets of shuffle relations of polylogarithms and regularized MZVs are derived by a single *** also take this approach to study the extended double shuffle relations of MZVs by comparing these shuffle relations with the quasi-shuffle relations of the regularized MZVs in our previous approach of MZVs by renormalization.

关键词： multiple zeta values polylogarithms Rota-Baxter algebras