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Virtual multi-dimensional internal bonds model and its application in simulation of rock mass

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Science china(Technological sciences) 2008年第2期51卷 192-201页

作者： ZHANG ZhenNan1,2 & GE XiuRun3,4 1 Department of Civil Engineering,shanghai University,shanghai 200072,china 2 shanghai institute of applied Mathematics and Mechanics,shanghai University,shanghai 200072, china 3 institute of Geotechnical Engineering,shanghai Jiao Tong University,shanghai 200030,china 4 institute of Rock and Soil Mechanics,chinese academy of sciences,Wuhan 430071,china 1. Department of Civil Engineering Shanghai University Shanghai 200072 China 2. shanghai institute of applied Mathematics and Mechanics Shanghai University Shanghai 200072 China 3. institute of Geotechnical Engineering Shanghai Jiao Tong University Shanghai 200030 China 4. institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China

VMIB (virtual multi-dimensional internal bonds) is a multiscale mechanical model developed from the VIB (virtual internal bond) theory. In VIB theory,the solid mate-rial is considered to consist of random-distributed material particles in microscale. These particles are connected with normal bonds. The macro constitutive relation is derived from the cohesive law between particles. However,in VMIB,the micro particles are connected with both normal and shear bonds. The macro constitutive relation is derived in terms of bond stiffness coefficients. It has been theoretically certified that there exists a corresponding relationship between the two bond stiffness coefficients and the two macro material constants,i.e. the Young’s modulus and Poisson ratio. This corresponding relationship suggests that it should be necessary and sufficient to simultaneously account for the normal and shear interactions between particles. Due to the fact that the fracture criterion is directly incorporated into the constitutive relation,both VIB and VMIB present many advantages in simulating fractures of materials. In the damage model of rock mass,a damage tensor is usually defined to describe the distribution of cracks. The damage value in one direction determines the relative stiffness of rock mass in this direction. In VMIB solid,the relative distribution density of micro bonds in one direction determines the relative macro stiffness of the material in this direction. The effects of the damage value and the relative distribution density of bonds are consistent. To simulate the failure behavior of rock mass with VMIB,the presented paper sets up a quantitative relationship between the damage tensor and the rela-tive distribution density of bonds. Comparison of the theoretical and the experi-mental results shows that VMIB model can represent the effect of distributed cracks on rock mass with this relationship. The presented work provides a founda-tion for further simulating fracture behavior

关键词： VMIB (virtual multi-dimensional internal bonds) rock mass VIB (virtual internal bonds) multi-cracked body numerical simulation

Transient species and its properties of melatonin

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Science china Chemistry 2006年第4期49卷 308-314页

作者： ZHU Hongping1,2, ZHANG Zhaoxia1,2, ZHAO Hongwei1, WANG Wenfeng1 & YAO Side1 1. shanghai institute of applied physics, chinese academy of sciences, shanghai 201800, china 2. Graduate University of the chinese academy of sciences, Beijing 100049, china 1. shanghai institute of applied physics Chinese Academy of Sciences Shanghai 201800 China 2. Graduate University of the chinese academy of sciences Beijing 100049 China

The photo-physical and photo-chemical properties of melatonin (ML) werestudied by 266 nm laser flash photolysis (LFP). ML undergoes photo-ionization to produce radicalcation of ML (ML^(·+))and hydrated electrons (e_(aq)^-), while excited triplet state ~3ML~* is alsoformed during photolysis. The oxidation via one electron transfer from ML to SO_4^(·+) and thetriplet state of riboflavin (~3RF~*) has been also investigated and the rate constants for theprocess have been determined to be 8.0x10^9 and 1.4x10^9 L·mol^(-1)·s^(-1) respectively. Theradical cation of 2,2''-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS^(·+)) scavengingcapacities of melatonin and other antioxidants are compared in this paper.

关键词： melatonin, laser flash photolysis, photoionization, triplet state.

Serine racemase expression in mouse cerebral cortex after permanent focal cerebral ischemia

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Acta Pharmacologica Sinica 2004年第4期25卷 38-43页

作者： Li-zhenWANG, Xing-zu ZHU2 Department of Pharmacology, shanghai institute of Materia Medica, shanghai institutes for Biological sciences, chinese academy of sciences, shanghai 201203, china Department of Pharmacology Shanghai Institute of Materia MedicaShanghai Institutes for Biological Sciences Chinese Academy of Sciences

AIM: To study the alterations of the expressions of serine racemase in C57BL/6 mouse brain after permanent focal cerebral ischemia. METHODS: The mRNA level and the protein level of serine racemase were assayed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. The amount of D-serine and L-serine were measured by HPLC. RESULTS: High levels of serine racemase were constitutively expressed in the normal cortex of mouse. At early stage after middle cerebral artery occlusion (MCAO), no significant change in expression of serine racemase was observed in temporoparietal cortex in ipsila- teral hemisphere. However, delayed transient decreases of serine racemase in both mRNA and protein levels were detected from d 6 to d 10 after ischemia. Correspondingly, D-serine concentration also declined in the ipsilateral cortex during this period when compared with the D-serine level in the contralateral cortex. CONCLUSION: Delayed decreases in serine racemase expression and D-serine level occurred in the temporoparietal cortex at the late stage after focal cerebral ischemia.

关键词： D-serine L-serine serine racemase inbred C57BL mice brain ischemia

Photolysis of benzophenone with two-step two-laser excitation

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Science china Chemistry 2001年第6期44卷 582-586页

作者： CAI Xichen HAN Zhenhui , YAO Side& LIN NianyunLaboratory of Radiation Chemistry, shanghai institute of Nuclear Research, chinese academy of sciences, shanghai 201800, china 1. Laboratory of Radiation Chemistry Shanghai Institute of Nuclear Research Chinese Academy of Sciences 201800 Shanghai China

The first laser excites a molecule to a lower triplet state and another sequential laser excites it resonantly to higher triplet states or makes it ionization. This two-step two-laser method provides a novel way to study the electron transfer or charge transfer of excited molecules. The higher excited benzophenone and its radical cation can be observed under the time-resolved absorption method when it was excited to lower triplet state by one laser and another one exciting it to higher triplet states resonantly. The higher excited benzophenone molecules undergoing inter-molecular hydrogen abstraction with iso-propylalcohol molecules are faster than the lower ones.

关键词： two-laser photolysis upper triplet states benzophenone

Densification and Microstructure of β-sialon/Nano-size SiC Composites

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Journal of Materials Science & Technology 1997年第4期13卷 339-341页

作者： Cheng ZHANG Danyu JIANG Qiang LI and Weiying SUN (shanghai institute of Ceramics, chinese academy of sciences, shanghai 200050, china) shanghai institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

β-sialon/nano-size SiC composite ceramic with DyAG(Dy3Al5O12) as grain boundary phase was fabricated through hot-pressing. The effect of nano-size SiC on densification, phase composition, microstructure and mechanica... 详细信息

关键词： Nano SiC Densification and Microstructure of sialon/Nano-size SiC Composites

A　Novel　Method　of　Selecting　SLM──PhaseRetardationofaBirefringentCrystal

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chinese Journal of Lasers 1996年第4期B5卷 293-300页

作者： SHEN Xiaohua CHEN Shaohe LIN Zunqi(shanghai institute of Optics and Fine Mechanics,chinese academy of sciences,shanghai 201800) shanghai Inst of Optics and Fine Mechanics Chinese Acad of Sciences Shanghai China

ＡＮｏｖｅｌＭｅｔｈｏｄｏｆＳｅｌｅｃｔｉｎｇＳＬＭ──ＰｈａｓｅＲｅｔａｒｄａｔｉｏｎｏｆａＢｉｒｅｆｒｉｎｇｅｎｔＣｒｙｓｔａｌ￥ＳＨＥＮＸｉａｏｈｕａ；ＣＨＥＮＳｈａｏｈｅ；ＬＩＮＺｕｎｑｉ（ＳｈａｎｇｈａｉＩ... 详细信息

ＡＮｏｖｅｌＭｅｔｈｏｄｏｆＳｅｌｅｃｔｉｎｇＳＬＭ──ＰｈａｓｅＲｅｔａｒｄａｔｉｏｎｏｆａＢｉｒｅｆｒｉｎｇｅｎｔＣｒｙｓｔａｌ￥ＳＨＥＮＸｉａｏｈｕａ；ＣＨＥＮＳｈａｏｈｅ；ＬＩＮＺｕｎｑｉ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＯｐｔｉｃｓａ...

关键词： birefringent crystal phase retardation loss modulation SLM

Mathematical feature of photon spectra produced in ultra-relativistic heavy-ion collision

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Nuclear Science and Techniques 1997年第1期8卷 18-22页

作者： Ai Xiao Bai(Ai Hsiao Bai) ( shanghai institute of Nuclear Research, the chinese academy of sciences, shanghai 201800 ) shanghaiinstituteofNuclearResarch theChineseAcademyofSciencesShanghai201800

ＭａｔｈｅｍａｔｉｃａｌｆｅａｔｕｒｅｏｆｐｈｏｔｏｎｓｐｅｃｔｒａｐｒｏｄｕｃｅｄｉｎｕｌｔｒａｒｅｌａｔｉｖｉｓｔｉｃｈｅａｖｙｉｏｎｃｏｌｉｓｉｏｎＡｉＸｉａｏＢａｉ（ＡｉＨｓｉａｏＢａｉ）（Ｓｈａｎ... 详细信息

ＭａｔｈｅｍａｔｉｃａｌｆｅａｔｕｒｅｏｆｐｈｏｔｏｎｓｐｅｃｔｒａｐｒｏｄｕｃｅｄｉｎｕｌｔｒａｒｅｌａｔｉｖｉｓｔｉｃｈｅａｖｙｉｏｎｃｏｌｉｓｉｏｎＡｉＸｉａｏＢａｉ（ＡｉＨｓｉａｏＢａｉ）（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＮｕ...

关键词：重离子碰撞夸克-胶子等离子体光子谱

Tape Casting of Al_2O_3-TiB_2/Al_2O_3-Nano-TiC Multilayer Composites

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Journal of Materials Science & Technology 1997年第4期13卷 324-326页

作者： Yuping ZENG Dongliang JIANG Shouhong TAN and Jingkun GUO(shanghai institute of Ceramics, chinese academy of sciences, shanghai 200050, china) shanghai institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

Ceramic tapes, containing Al2O3-25 wt pct TiB2(B) and Al2O3-25 wt pct nano-TiC (c), have been obtained by tape casting process. Numerous tapes (about 60～80 tapes) were prepared by stacking in turn the composition (B) and (C), laminating under 10 MPa pressure, eliminating the solvent and burning out the polymer additives. The final green bodies were hot pressed at 1750℃ and 30 MPa. The composite has a bending strength of 568 MPa and a fracture toughness of 5.8 M Pa·m1/2. SEM analysis exhibits that Al2O3 particle growth was inhibited by TiC particles in C. but TiB2 particles could not hinder Al2O3 growth in B. The curves of GTA indicates that all organic additives could be removed completely above 600℃

关键词： Nano TiB Al Tape Casting of Al2O3-TiB2/Al2O3-Nano-TiC Multilayer Composites TiC

Second Harmonic Generation from Electrically Polarized CdSxSe1-x Microcrystallite Doped Glass

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chinese Journal of Lasers 1997年第5期B6卷 419-423页

作者： CHEN Hongbing XU Jianghua ZHU Congshan LU Xingze GAN Fuxi (shanghai institute of Optics & Fine Mechanics, chinese academy of sciences,shanghai 201800, china Department of physics, Fudan Universith,shanghai 200433, china) shanghai Inst of Optics and Fine Mechanics Chinese Acad of Sciences Shanghai China

Second harmonic generation has been observed from CdSxSe1-x microcrystallite doped glass, which is electrically polarized at 200℃ for 60 min under an applied DC field of 7kV. To explain the effect, it is proposed th... 详细信息

关键词： CdS_xSe(1-x) microcrystallite doped glass second harmonic generation electrical polarization thermal erasure dipole orientation