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Current progress and prospects of induced pluripotent stem cells

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Science china(Life Sciences) 2009年第7期52卷 622-636页

作者： CHEN LingYi & Liu Lin key laboratory of Bioactive materials of ministry of education,College of Life Sciences,Nankai university,Tianjin 300071,china key laboratory of Bioactive materials of ministry of education College of Life Sciences Nankai University Tianjin China

Induced pluripotent stem(iPS) cells are derived from somatic cells by ectopic expression of few transcription *** embryonic stem(ES) cells,iPS cells are able to self-renew indefinitely and to differentiate into all types of cells in the *** cells hold great promise for regenerative medicine,because iPS cells circumvent not only immunological rejection but also ethical *** the first report on the derivation of iPS cells in 2006,many laboratories all over the world started research on iPS cells and have made significant *** paper reviews recent progress in iPS cell research,including the methods to generate iPS cells,the molecular mechanism of reprogramming in the formation of iPS cells,and the potential applications of iPS cells in cell replacement *** problems that need to be addressed and the prospects for iPS research are also discussed.

关键词： induced pluripotent stem(iPS) cells somatic cell reprogramming pluripotency

Influence of Alternative magnetic Field on the Diffusion of Al and Mg

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Journal of materials Science & Technology 2004年第4期20卷 457-459页

作者： Xiaotao LIU, Jianzhong CUI, Yanhui GUO, Xiaoming WU and Jun ZHANGThe key laboratory of Electromagnetic Processing of materials, ministry of education, Northeastern university, Shenyang 110004, china Mat. Electromagnetic Proc. Lab. Northeastern Univ. Shenyang 110004 China

The influence of an alternative magnetic field on the diffusion of Al and Mg in AI-Mg diffusion couple is studied. The diffusion zone is composed of two intermediate phases, namelyβ and γ phase. Thickness of each intermediate phase is examined. The results show that the alternative magnetic field increases the thicknesses of βand γ phase zone and the layer growth ofβ and γphase obeys the parabolic rate law. The growth rate of the β and γ phase are increased with the application of the alternative magnetic field. This change is manifested through a change in the frequency factor k0 and not through a change in the activation energy Q. The frequency factor k0 for intermediate phase growth with an alternative magnetic field is 39.95 cm2/s for 7 phase and 2.84×10-4 cm2/s for β phase compared with those without the magnetic field is 22.4 cm2/s for 7 phase and 1.53×10-4 cm2/s for β phase.

关键词： Alternative magnetic field Al-Mg Couple Intermediate phase Thickness Diffusion

Molecular dynamics simulation of amorphous segregation in Ag-Rh alloys

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Rare Metals 2003年第3期22卷 164-168页

作者： ZHANG Jingxiang and BIAN Xiufangkey laboratory of Liquid Structure and Heredity of materials, ministry of education, Shandong university, Jinan 250061, china Shandong university Key Laboratory of Liquid Structure and Heredity of Materials Ministry of Education Jinan 250061

Molecular dynamics simulation was carried out to investigate the liquid andamorphous microstructures of binary Ag_x-Rh_((100-x)) (x = 25, 50, 75 in atom fraction) *** feature of homogeneous interatomic binding of Ag-Rh liquid was found and probed, whichcan be retained into amorphous solids upon rapid cooling. Homogeneous binding may occur when thedifference in the elemental atomic sizes is less than 10%. The icosahedra in liquid before theformation of amorphous state exist in a stable state and the network formed by 1551-clusters inmolten alloys would inhibit the crystallization and diffusion of atoms. A higher degree of1551-clusters will be favorable to form metallic glasses.

关键词： metallic glass amorphous segregation molecular dynamics liquid structure Ag-Rh alloy

Effect of High-energy Ball Milling on Synthetic Reaction in Al-TiO_2-C System

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Journal of Wuhan university of Technology(materials Science) 2005年第4期20卷 50-54页

作者：寇生中 State key Lab of Advanced Nonferrous materials Lanzhou University of TechnologyLanzhou 730050China

High-energy ball milling has a great influence on the temperature characters of synthetic reaction in Al-TiO2-C system by changing the size,distribution state and wet ability of *** temperature characters（reaction ignition time,ignition temperature *** maximum temperature and temperature rising rate）were changed by different milling *** longer the milling *** earlier the *** quicker the temperature rise and the higher the maximum *** the milling time exceeded 10 hours,the reactivity of reactants was so high that the synthetic reaction could take place at 850℃ directly without a long time pretreatment at 670℃.The microstructure of synthetic composites became uniform and the reinforced particles（TiC and α-Al2O3）became fine with milling time increasing.

关键词： composites synthetic reaction Al2O3p-TiCp/Al temperature character microstructure

A constitutive model of frozen soil with damage and numerical simulation for the coupled problem

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Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 699-711页

作者： ZHU ZhiWu, NING JianGuo& MA Wei 1 School of Mechanics and Engineering, Southwest Jiaotong university, Chengdu 610031, china 2 State key laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, china 3 key laboratory of Frozen Soil Engineering, CAREERI, CAS, lanzhou 730000, china School of Mechanics and Engineering Southwest Jiaotong University Chengdu China State key laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing China key laboratory of Frozen Soil Engineering CAREERI CAS Lanzhou China

Based on the microcosmic mechanics of composite materials, an elastic constitutive model for frozen soil with damage is presented. For frozen sandy soil with a range of ice contents and under a range of temperature conditions, quantitative results determined by this constitutive model agree with practically measured stress-strain curves. After numerically simulating the coupled water, temperature and stress fields of channel frozen and frozen roadbed using a self-developed finite-element routine, more accurate and practical calculation results for the temperature field coupled with stress, displacement and strain fields are obtained; the results match predictions and tests undertaken by earlier researchers. Our results support the reliability of our routine for calculating interdependent physical quantities of frozen soil and for describing the relationships between them. Our program can offer necessary constraints for engineering design and construction in permafrost regions.

关键词： frozen soil microcosmic mechanics roadbed coupling stress field

Test of magnetic susceptibility and grain-size age models of loess

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Progress in Natural Science:materials International 2007年第11期17卷 1312-1317页

作者： Chen Yimeng1,2,3, Feng Zhaodong4 and Gong Huili1,2(1. MOE and key laboratory of Resources Environment and GIS of Beijing, Beijing 100037, china 2. key laboratory of 3D information Acquisition and Application, The Capital Normal university, Beijing 100037, china 3. Department of Economics & Management of Huizhou university, Huizhou 516007, china 4. key laboratory of Western china’s Environmental Systems, ministry of education, lanzhou university, lanzhou 730000, china) key laboratory of Resources Environment and GIS of Beijing Beijing 100037 China key laboratory of 3D information Acquisition and Application Capital Normal University Beijing 100037 China Department of Economics and Management Huizhou University Huizhou 516007 China key laboratory of Western china's Environmental Systems Lanzhou University Lanzhou 730000 China

Ages of the stratigraphic boundary MIS1/2 and MIS3/4 of the Yuanbu loess section in Linxia are used as the basis of the nodal control age. The age of MIS1/2 and MIS3/4 are obtained from the latest international research result—the climatic events recorded in the stalagmite in the Hulu Cave in Nanjing, that MIS1/2 is 11.5 kaB.P. and MIS3/4 is 59.8 kaB.P.. The ages of the two climatic events contain three nodal age control models (Model 1: 0 kaB.P.—59.8 kaB.P.; Model 2: 0 kaB.P.—11.5 kaB.P. and 11.5 kaB.P.—59.8 kaB.P.; Model 3: 11.5 kaB.P.—59.8 kaB.P.), which are used as the nodal control age separately. The deposition times of various stratigraphic horizons are calculated by using the magnetic susceptibility age model and grain-size age model, and then compared with each other. In addition, the AMS14C age, OSL age and the ages of YD and H events are compared with the ages of the corresponding horizons calculated by the three models of nodal control ages. From the analyses of lithologic characters and climatic stages it has been found that both the magnetic susceptibility age model and the grain-size age model have some defects. Because the accurate control ages are selected as the nodal points of the glacial period or interglacial period, the stratigraphic deposition times determined by the high resolution of magnetic susceptibility age model and grain-size age model approximate to the actual ages. As for the relative accuracy of the two age models, the magnetic susceptibility age model is more accurate than the grain-size age model.

关键词： loess nodal control age magnetic susceptibility age model grain-size age model test

Estimation to the turbulent kinetic energy dissipation rate and bottom shear stress in the tidal bottom boundary layer of the Yellow Sea

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Progress in Natural Science:materials International 2007年第3期17卷 289-297页

作者： LIU Zhiyu and WEI Hao (key laboratory of Physical Oceanography, State education ministry, Ocean university of china, Qingdao 266003, china) key laboratory of Physical Oceanography Ocean University of China Qingdao 266003 China

High frequency velocity fluctuations were measured by using an acoustic Doppler velocimeter (ADV) in the tidal bottom boundary layer (BBL) of the Yellow Sea (YS) for 25 h. The turbulent kinetic energy dissipation rate and the bottom shear stress were estimated and analyzed. Results show that: (1) in the tidal BBL of the YS, the variations of the dissipation rate and the bottom shear stress during 25 hare (1.8×10-8-3.4×10 -5) W·kg-1 and (6.6×10-4-7.5×10-1) N·m - 2 respectively, indicating that there are strong dissipations in the tidal BBL of the YS; (2) in the well-mixed tidal BBL, the turbulence is mainly shear-induced locally and the production and dissipation are generally in equilibrium; (3) for the seas where the semidiurnal tidal current is dominant, both the dissipation rate and the bottom shear stress exhibit a strong quarter-diurnal variation; (4) the mean bottom drag coefficient Cd (0.45) is 0.0017 (corresponding Cd( 1.00) = 0.0015), but it has significant variations (0.0005-0.0082). The mean bottom roughness length is 2.8×10-5 m.

关键词： tidal bottom boundary layer turbulent kinetic energy dissipation rate bottom shear stress ADV the Yellow Sea.

A study on odd-parity high-lying states of the Sm atom with three-color resonant excitation

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Science china(Physics,Mechanics & Astronomy) 2011年第6期54卷 1124-1130页

作者： LI Ming 1,2,DAI ChangJian 1,2 & XIE Jun 1,2 1 key laboratory of Display materials and Photoelectric Devices,ministry of education,Tianjin 300191,china 2 School of Science,Tianjin university of Technology,Tianjin 300384,china key laboratory of Display materials and Photoelectric Devices Ministry of Education Tianjin China School of Science Tianjin University of Technology Tianjin China

The odd-parity high-lying states of the Sm atom are investigated systematically by a three-color resonant excitation scheme with two different excitation *** two intermediate states,4f 6 6s7s 7 F 0 and 4f 6 6s7s 7 F 1 are employed for paths I and II,***-seven bound states are detected with paths I and II in the energy range between 44188 and 45515 cm 1,while 64 autoionizing states are found in the energy range from 45528 to 45761 cm *** only the level energies of all observed states,but also the line widths of autoionizing states are *** possible impact of configuration interaction on the line shape of autoionizing states is also *** addition,the total angular momentum is assigned uniquely to most of the states,whereas the information about the relative line intensity of all states is also presented.

关键词： high-lying states odd-parity the Sm atom resonant excitation

Whisker Orientation Function and Elastic Modulus of the as-cast 20% SiC_W/Mg Composite

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Rare Metals 2001年第4期20卷 270-274页

作者： Chuanhai Jiang1, Jiansheng Wu1, Mingyi Zheng2, Dezun Wan 2 1) key laboratory for High Temperature materials and Tests of the ministry of education, Shanghai Jiaotong university. Shanghai 200030, china 2) School of materials Science and Engineering, Harb 上海交通大学教育部高温材料及高温测试重点实验室上海 200030 哈尔滨工业大学黑龙江哈尔滨 150001

The relationship between the plane-orientation function and the space-orientation function of whiskers in whisker-reinforced metal matrix composites was analyzed theoretically. The actual orientation of whiskers in the as-cast 20%SiCw/Mg composite (SiCw content in volume fraction) were investigated, and the elastic modulus of the composite was measured with an ultrasonic velocity analyzer. Results show that there is an evident difference between the plane-orientation function and the space-orientation function of whiskers and the space-orientation function can represent the actual condition of the composite. Only by using the space-orientation function of whiskers, the difference of elastic modulus of the as-cast composite in different directions can be explained reasonably.

关键词： SiC whisker Mg composite whisker orientation elastic modulus