检索结果-南通市图书馆

Theoretical analysis and experiment of micromechanics and mechanics-optics coupling of distributed optic-fiber crack sensing

在线全文

学校读者我要写书评

暂无评论

中国科学：技术科学英文版 2011年第S1期54卷 185-191页

作者： LIU HaoWu 1,2,CHEN Jiang 2,SUN Man 3.& DING Rui 2 1 State Key Laboratory of Hydraulics and Mountain River engineering,sichuan university,{3. 610065,china 2 School of Water Resource Hydropower,sichuan university,{3. 610065,china 3.School Electrical engineering and Information,sichuan university,{3. 610065,china State Key Laboratory of Hydraulics and Mountain River engineering Sichuan University School of Water Resource Hydropower Sichuan University School Electrical engineering and Information Sichuan University

The micromechanical behaviors and mechanics-optics coupling effects of optic-fiber-concrete complex in the distributed optic-fiber sensing concrete-crack technology,which was used in health monitoring of Wu Gorge Bridge on Yangtze River and a large dam successfully,have been investigated.A micromechanical theoretical analysis method and micromechanical frictional contact bi-interface model,as well as a modified optical theoretical analysis method of the mechanics-optics coupling effects are presented.A series of verification experiments,including mechanical experiments and mechanics-optics coupling experiments,have been *** results of micromechanical theoretical analysis and the analysis of the modified theory of mechanics-optics coupling along with mechanical and optical experimental data are shown to be in close *** the micromechanical theory and the modified theory of mechanics-optics coupling with their analysis methods can not only enhance credibility of this novel distributed sensing technology but also provide a way to understand its sensing mechanism and optimize its technical details and system.

关键词： optic-fiber sensing mechanics-optics coupling micromechanics health monitoring concrete structure crack detection

SOLUTION CRYSTALLIZATION OF METALLOCENE SHORT CHAIN BRANCHED POLYETHYLENE:MORPHOLOGY AND MECHANISM

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2000年第1期18卷 45-49页

作者： Qiang Fu Rong-ni Du Fang-Chyou Chiu department of Polymer science & Materials, sichuan university, {3., sichuan 610065, china department of Chemical engineering, Chang Gong university, Taoyun, Taiwan, china 四川大学四川成都 Chang Gong university 台湾

Solution crystallization of metallocene short chain branched polyethylene (SCBPE) was carried out and very nice single crystals were obtained. Compared with single crystals grown from linear polyethylene, SCBPE single crystals are dirty due to intermolecular heterogeneity The crystal morphology changes with crystallization temperatures. Lozenge, truncated lozenge, hexagonal, rounded and elongated crystal morphologies have been found at much lower crystallization temperature than in linear polyethylene. The electron diffraction shows there is a possibility that the single crystals may have hexagonal packing in a crystallization temperature range. The lateral habits of single crystal are discussed based on roughening theories.

关键词： metallocene SCBPE single crystal roughening face growth mechanism

Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of N_(2)molecule

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 385-398页

作者： REN Weiyi1,2, SUN Weiguo1, HOU Shilin3.& FENG Hao4 1. Institute of Physics, College of Chemical engineering, sichuan university, chengdu {3., china 2. Institute of Theoretical Physics, Xihua Normal university, Nanchong 63.002, china 3. department of Physics, china Oceanography university, Qingdao 266003. china 4. College of Physics, sichuan university, chengdu {3., china Institute of Physics College of Chemical Engineering Sichuan University Chengdu China Institute of Theoretical Physics Xihua Normal University Nanchong China department of Physics China Oceanography University Qingdao China College of Physics Sichuan University Chengdu China

It is usually very difficult to directly obtain molecular dissociation energy De and all accurate high-lying vibrational energies for most diatomic electronic states using modern experimental techniques or quantum theories, and it is also very difficult to give accurate analytical expression for diatomic molecular dissociation energy. This study proposes a new analytical formula for obtaining accurate molecular dissociation energy based on the LeRoy and Bernstein’s energy expression in dissociation limit. A set of full vibrational energy spectra for some electronic states of N2 molecule are studied using the algebraic method (AM) suggested recently, and the corresponding accurate molecular dissociation energies are evaluated using the proposed new formula and high-lying AM vibrational energies. The results show that the AM spectra and the new theoretical dissociation energies agree excellently with experimental data, and thereby providing a new physical approach to generating accurate dissociation energies for electronic states of diatomic molecules.

关键词： vibrational energy, dissociation energy, nitrogen molecule, algebraic method.

Shape Memory Effect of As-aged Fe-14Mn-5Si-8Cr-4Ni-0.2C Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2000年第4期16卷 424-426页

作者： Yuhua WEN, Ning LI and Mingjing TU (department of Materials Shaping and Controlling engineering, sichuan university, {3. 610065, china) department of Materials Shaping and Controlling engineering Sichuan University Chengdu 610065 China

The effects of aging temperature on shape memory effect, mechanical properties and microstruc-ture of Fe-14Mn-5Si-8Cr-4Ni-0.2C shape memory alloy have been studied. The results showed that the second phase particles rich in chromium, manganese and silicon precipitate during aging, and thereby increase the hardness and strength of the alloy. The shape recovery ratio can be remarkably improved by aging and a maximum value can be obtained at 1223.K, which is 68% higher than that of the specimen in solid solution state. When the aging temperature is below 1223.K, the amount of second phase particles increases as the aging temperature increases. The size of austenite grain increases with increasing aging temperature. When the temperature is over 1223.K, the second phase particles can not precipitate. The lack of second phase particles and the increase of grain size make the hardness and shape recovery ratio drastically decrease, when the temperature is over 1223.K.

关键词： Mn Shape Memory Effect of As-aged Fe-14Mn-5Si-8Cr-4Ni-0.2C Alloy As Fe Cr Ni Si

Effect of barium on the refinement of primary aluminum and eutectics in a hypoeutectic Al-Si alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2003年第3期22卷 192-196页

作者： LI Wei, FAN Hongyuan, ZHANG Xianju, and SHEN BaoluoSchool of Manufacturing science and engineering, sichuan university, {3. 610065, china School of Manufacturing science and engineering Sichuan University Chengdu 610065

The effect of barium on the refinement of primary aluminum and on themodification of eutectics in a hypoeutectic aluminum-silicon alloy was investigated. The resultsindicate that barium not only modifies the eutectic silicon but also refines the primary aluminumand there is a relationship between the retained barium and the second spacing of primary *** of barium-treated commercial Al-Si hypoeutectic alloy show that barium is a bettermodifier than sodium when there is a longer holding time.

关键词： non-ferrous metal barium modification primary aluminum eutectic Al-Sialloy

Land Use of the Three Gorges Reservoir Area and the Effect on Its Landscape Pattern in the Recent 50 Years

在线全文

学校读者我要写书评

暂无评论

Wuhan university Journal of Natural sciences 2006年第4期11卷 910-914页

作者： HUANG Zhiqin 1,2,3., ZHOU Wancun 1 ,ZHOU Jieming 4 , ZHU Mingcang 3.5 1. Institute of Mountain Hazards and Environment, Chinese Academy of sciences , chengdu 610041, sichuan,{3. 2. Graduate university of Chinese Academy of sciences, Beijing 100049,{3. 3. sichuan Institute of Land Resource Management, chengdu 610041, sichuan ,{3. 4. department of Resources and Environment science, sichuan Normal university , chengdu 610061, sichuan,{3. 5. College of Information engineering, chengdu university of Technology, chengdu 610059, sichuan,{3. Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu Sichuan China Graduate university of Chinese Academy of sciences Beijing China sichuan Institute of Land Resource Management Chengdu Sichuan China department of Resources and Environment science Sichuan Normal University Chengdu Sichuan China College of Information engineering Chengdu University of Technology Chengdu Sichuan China

The paper makes detailed analysis on the changing processes of the main types of land use in Three Gorges Reservoir Area through the techniques of RS （Remote Sense） and GIS （Geography Information System）. Based on the theory of landscape ecology, many types of landscape pattern indexes are calculated and made correlation analysis. The results indicate that： in 1995 the ecological environment of Three Gorges Reservoir Area was the most vulnerable in the recent 50 years, but resumed in 2002; the landscape pattern diversity index, fractal dimension index and fragmentation index has close correlation with the area of land use/cover change （LUCC）. The research also releases that the increase of the cultivated land, grassland and construction land deteriorates the landscape ecological pattern, while the increase of forest land area will help restore the landscape ecological pattern to its original state. The rapid change of grassland is an important index of the change of landscape pattern, because it has the most effect on change of landscape pattern index.

关键词： the Three Gorges Reservoir Area land use/cover change landscape pattern.

Studies on the analytical potential energy function of diatomic molecular ion XY^+ using variational method

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2004年第2期47卷 154-164页

作者： LIU Guoyue1,3. SUN Weiguo1,2 & FENG Hao1 1. Institute of Physics, sichuan university, chengdu 610065,{3. 2. College of Chemical engineering, sichuan university, chengdu 610065,{3. 3. Mianyang Teacher抯 College, Mianyang 621000,{3. Correspondence should be addressed to Sun Weiguo (e-mail: weiguosun@*** or guoyueliu@ ***) Institute of Physics Sichuan University Chengdu China Mianyang Teacher's College Mianyang China College of Chemical engineering Sichuan University Chengdu China

A new analytical potential energy function for diatomic molecular ion XY+ is proposed based on the energy consistent method (ECM). The Coulomb potential included in the new ionic potential contains multipole corrections, converges quickly and is variationally, changeable. The new potential and the ECM are applied to variationally studying the potential energies of eight electronic states of several diatomic molecular ions: the A2π state of CO+, the X2∑ g + state of Li 2 + , the X2∑ g + state of He 2 + , the 12∏u state of Na 2 + , the A2∏u state of N 2 + , the X1∑+ state of KrH+, the X2∑+ state of SiO+ and the A2π state of SO+ ion. The present results agree excellently with the experiment-based Rydberg-Klein-Rees (RKR) potentials, and are superior to the commonly used Huxley-Murrell-Sorbie (HMS) analytical potentials, and are better in some cases than some quantum mechanicalab initio potentials in the ionic asymptotic and dissociation regions.

关键词： potential energy, diatomic ion, electronic state, variational method.

Studies on Barriers for Promotion of Clean Technology in SMEs of china

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2005年第1期3卷 9-17页

作者： Peng Sizhen , Liu Yan , Shi Han 1 2 & Zhong Ping 3.1. The Administrative Centre for china’s Agenda21, Beijing 100089, china 2. Yale School of Forestry & Environmental Studies, New Haven CT 06511, the U.S.A. 3. department of Environmental {3. and engineering, sichuan university, chengdu sichuan 610065, china The Administrative Centre for china’s Agenda21 Beijing 100089 China Yale School of Forestry and Environmental Studies New Haven CT 06511 United States department of Environmental science and engineering Sichuan University Chengdu Sichuan 610065 China

After more than 10 years efforts on awareness raising and promotion, the concept of cleaner production (CP) has been adopting as a strategic approach to balance economic benefits and environmental protection for china’s industries. However, it is also found that clean technology is difficult to be adopted and implemented in Chinese Small and Medium-sized Enterprises (SMEs) because of certain barriers. This paper investigates these barriers among three stakeholders--governments, enterprises and experts. The Analytic Hierarchy Process (AHP) was employed to prioritize the relative importance of the twenty fine-selected barriers, which were classified into four barrier categories. The findings reveal that the exterior barriers of policy and financial barriers should be stressed rather than the inner barriers of technical and managerial barriers, although they are also very important. Absence of incentives on economic policies, lax enforcement of environmental regulations and high initial capital cost were the most important barriers to adoption of Clean Technologies (CT) in china.

关键词： Cleaner Production Clean Technologies Barrier Study Small and Medium Enterprises

Electronic structure and magnetism of R(Fe,Si)_(12) (R=Y,Nd)

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2006年第2期49卷 195-202页

作者： SUN Guang’ai1, CHEN Bo1, DU Honglin2, FAN Zhijian1, GAO Tao3.& QI Xinhua3.. Institute of Nuclear Physics and Chemistry, china Academy of engineering Physics, Mianyang 621900, china 2. {3. of physics, Peking university, Beijing 100871, china 3. Institute of Atomic and Molecular Physics, sichuan university, chengdu 610065, china Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang China department of physics Peking university Beijing China Institute of Atomic and Molecular Physics Sichuan University Chengdu China

The newly developed full-potential linearized augmented plane wave (LAPW) and local orbitals (lo) based on standard APW methods are briefly introduced, and the structure and magnetic properties of R(Fe, Si)12 compounds (R = Y, Nd) are calculated using the method. The distribution of Si at different sites is analyzed based on total energy of one crystal unit with structure having been optimized. The characters of magnetic mo-ments, total density of states (TDOS) and partial density of states (PDOS) for different crystal sites Si occupies are obtained and analyzed. The results show that the total mag-netic moments of RFe10Si2 (R = Y, Nd) are larger than those of RFe10M2 (M = Ti, V, Cr, Mn, Mo and W) and the hybridization mechanism is seen as follows. Si(8j) reduce the mag-netic moments of Fe at three sites, however, Si(8f) mainly reduce the magnetic moments of Fe(8i) and Fe(8j) atoms. The Curie temperature is markedly enhanced by the introduc-tion of Si atoms according to spin fluctuation of DOS at Fermi level.

关键词： (L)APW+lo method R(Fe Si)12(R = Y Nd) magnetic moment Density of state.