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Deposition of Bioactive Layer on NiTi Alloy by chemical Treatment

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Journal of Materials Science & Technology 2002年第6期18卷 534-537页

作者： Ya LIU, Xianjin YANG, Minfang CHEN, Shengli ZHU and Zhenduo GUISchool of Materials Science and Engineering, tianjin University, tianjin 300072.{2. Sch. of Mat. Sci. and Eng. Tianjin Univ. Tianjin 300072 China

A simple chemical method was developed for inducing bioactivity on NiTi alloys (50 at. pct by Ni/Ti). A layer of calcium phosphate was deposited on the surface to improve biocompatibility of the alloy. NiTi alloys were first etched in HNO3 aqueous solution, and then treated with boiling diluted NaOH solution. A rough surface was created and a thin TiO2.layer was formed on the surface. Pre-calcification was then introduced by immersing the treated NiTi alloys in supersaturated Na2.PO4 solution and supersaturated Ca(OH)2.solution in turn before calcification in simulated body fluid (SBF). A dense and uniform bonelike calcium phosphate (Ca-P) bioactive layer was formed on the surfaces of the specimen, which would improve their biocompatibility. Morphology and element analysis on NiTi surfaces during the treatments were investigated in detail by means of environment scanning electron microscopy (ESEM), energy dispersion X-ray spectroscopy (EDXS), and X-ray diffraction (XRD).

关键词： NiTi alloy chemical method Bioactive layer Biocompatibility

Principle of limitation of physical quantities and cyclic universe

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Science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 451-458页

作者： HE GuoZhu Department of Physics,Nankai University,tianjin 300071,china Department of Physics Nankai University Tianjin China

A close study of Heisenberg uncertainty principles reveals many significant facts,and all four major physical quantities,energy,time,momentum and length,have both lower and upper ***,many questions come *** are these limits?Some answers may lead to the understanding of the development of our *** is the shortest limit of time?At the beginning of big bang,there exists a tre-mendously short time,the Planck *** may be just the shortest time limit in our *** longest time limit might be the lifetime of our *** longest length might be the final diameter of our expanding *** these lead to a finite *** more coupling formulae are formed for the other two pairs of physical quantities,mass and speed,thermal energy and *** four physical quantities must also have *** already knew that speed has upper limit and temperature has lower *** these two formulae,Planck and Einstein equations are derived *** most other physical quantities are somewhat related to these major physical quantities,it seems that there exists a principle of limitation of physical quantities.A quantitative sketch of big bang is *** also shows that our universe will contract back to another big *** principle of limitation opens up some fields of *** may bring nature back to the harmony and determined world described by classical physics.

关键词： principle of limitation of physical quantities limits coupling formulae cyclic universe extension of conven-tional quantum mechanics no uncertainty for physical quantities quantitative evaluation of big bang

Solid-Liquid Equilibria of Succinic Acid in Cyclohexanone,Cyclohexanol and Their Mixed Solvents

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Transactions of tianjin University 2007年第1期13卷 42-47页

作者：樊丽华马沛生宋微微 School of chemical Engineering and Technology Tianjin University

Solubilities were measured for succinic acid dissolved in cyclohexanone, cyclohexanol and 5 of their mixed solvents at the temperature range from 2.1. 85 K to 358.37 K using a dynamic method. The solubility data were regressed by λh equation, with,the average absolute relative deviation 3.47%. The binary interaction parameter is 0.306 7 for the mixed solvent of oyolohexanone and cyclohexanol was determined by correlating the experimental solubilities with the modified λh equation. When the binary interaction parameter was determined it can be used to extrapolate the solubilities of succinic acid in mixed solvents of cyclohexanone and cyclohexanol at any *** average absolute relative deviation was 7. 69% by using the modified λh equation to correlate the solubility data, however, the average absolute relative deviation was 8.89% by using NRTL equation to correlate the solubility data. The results show that the accuracy of the modified λh equation is better than that of the NRTL equation for the solubility of succinic acid in the 5 mixed solvents of cyclohexanone and cyclohexanol.

关键词： solid-liquid equilibrium solubility correlation succinic acid cyclohexanone cyclohexanol mixed solvents

Thermodynamic Analysis of the Preparation Process of EB-PVD SiC Coating

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Journal of Wuhan University of Technology(Materials Science) 2009年第3期24卷 363-366页

作者：易剑 School of Mechatronics Engineering Taizhou University Laser Processing Center Tianjin Polytechnic University Center for Composite Materials Harbin Institute of Technology

The process of preparing SiC coating by electron beam-physical vapor deposition （EB-PVD） was discussed from viewpoint of thermodynamis. Results show that within the temperature range of 2.700-3 300 K, the ratio of SiC in the SiC coating doesn＇t change much and keeps around 0.7. Purity of the as-deposited SiC coating is not high. To improve the purity of the SiC coating, the SiC ingot is required to not be, necessary in full density but be fine-grained.

关键词： thermodynamics SiC coating EB-PVD ratio of SiC purity

New Developed Welding Electrode for Improving the Fatigue Strength of Welded Joints

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Journal of Materials Science & Technology 2002年第6期18卷 527-531页

作者： Wenxian WANG, Lixing HUO, Yufeng ZHANG, Dongpo WANG and Hongyang JINGCollege of Material Science and Engineering, tianjin University, tianjin 300072.{2. Coll. of Mat. Sci. and Eng. Tianjin Univ. Tianjin 300072 China

A new welding electrode, low transformation temperature electrode (LTTE), was introduced in this paper. It was described in design principle, mechanics, chemical compositions of their deposited metal and manufacturing methods. It was proved that the best transformation starting temperature from austenite to martensite of the deposited metal of LTTE was at about 191℃ and it was obtained by adding alloying elements such as Cr, Ni, Mn and Mo. The microstructure of the weld metal of the LTTE was low carbon martensite and residual austenite. The compressive residual stress was induced around the weld of the LTTE and the -145 MPa in compression could be obtained in middle of weld metal. The fatigue tests showed that the fatigue strength of the longitudinal welded joints welded with the LTTE at 2.106 cycles was improved by 59% compared with that of the same type of welded joints welded with conventional E5015 and the fatigue life was increased by 47 times at 162.MPa. It is a very valuable method to improve the fatigue performance of welded joints.

关键词： Low transformation temperature electrode Compressive residual stress Fatigue strength Welded joints

Two-photon spectroscopic behaviors and photodynamic effect on the BEL-7402.cancer cells of the new chlorophyll photosensitizer

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Science china Chemistry 2008年第6期51卷 529-538页

作者： ZHAO PeiDe1,2.CHEN Ping1,TANG GuoQing1,LIU JinWei2.LIN Lie1,GUO Peng1,YU Qing2. YAO JianZhong3,MA DongMing4,ZHANG GuiLan1 & CHEN WenJu1 1 Key Laboratory of Optoelectronic Information Science and Technology,Ministry of Education,Institute of Modern Optics,Nankai University,tianjin 300071,china 2.Department of Physics,Hebei University of Technology,tianjin 300130,china 3 College of Pharmacy,Second Military Medical University,Shanghai 2.0433,china 4 tianjin College of the Traditional Chinese Medicine,tianjin 300193,china Key Laboratory of Optoelectronic Information Science and Technology Ministry of Education Institute of Modern Optics Nankai University Tianjin China Department of Physics Hebei University of Technology Tianjin China College of Pharmacy Second Military Medical University Shanghai China tianjin College of the Traditional Chinese Medicine Tianjin China

The spectroscopic properties of a new chlorophyll derivate photosensitizer (CDP) are studied under the excitation wavelengths at 800 and 400 nm using femtosecond pulses from a Ti: sapphire laser. The damaging effect of CDP on the BEL-7402.cancer cells is also investigated upon two-photon illumination at 800 nm. The normalized fluorescence spectra of CDP in tetrahydrofuran (THF) show that two-photon and one-photon spectra have the same distributions and the same emission bands (675 nm). The lifetimes of two- and one-photon induced fluorescence of this molecule are of the order of 5.0 ns. By comparing the data it is shown that there is some difference between the two lifetimes, but the difference is less than one nanosecond. The two-photon absorption cross section of the molecule is also measured at 800 nm and estimated as about σ'_2.≈ 31.5x10^(-50)cm^4·s·photon^(-1). The results of two-photon photodynamic therapy (TPPDT) tests show that CDP can kill all of the tested cancer cells according to the usual Eosine assessment. Our results indicate that the two-photon-induced photophysical, photochemical and photosensitizing processes of CDP may be basically similar to those of one-photon excitation. These behaviors of the sample suggest that one may find other possible methods to estimate some photosensitizers' effects in details such as their distribution in cells and the reactive targets of the sub-cellular parts of some tumor cells via two-photon excitation {2..

关键词： photosensitizer chlorophyll derivate two-photon fluorescence two-photon absorption cross-section TPPDT BEL-7402 cell

Experimental study on high-voltage solar array sustained arc discharge induced by high charging

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Science china(Technological Sciences) 2007年第2期50卷 213-220页

作者： LI Kai1,2. XIE ErQing1, WANG Li2. LIU YanXia1, YANG Yang1, SUN YanZheng3, CUI XinYu3 & MAI ShengLi2.1 School of physical Science and Technology, Lanzhou University, Lanzhou 730000, china 2.Lanzhou Institute of Physics, Lanzhou 730000, china 3 tianjin Institute of Power Source, tianjin 300381, china School of physical Science and Technology Lanzhou University tianjin Institute of Power Source

It has been reported that sustained arc discharge induced by electrostatic discharge (ESD) could cause permanent damage to high-power and high-voltage solar array of spacecrafts. The paper focuses on ESD simulating experiments on Si and GaAs samples, and induces sustained arc discharge. The physical mechanism of sustained arc discharge is discussed by comparing the charging/discharging phenomena between Si and GaAs samples. The experiments show that sustained arc discharge can produce a permanent short-circuit channel between solar cell strings through which the solar array’s photovoltaic power may flow out sustainedly. The analyses show that sustained arc discharge strongly depends on solar array structure, solar array operating voltage, ESD characteristics and cell materials. Keywords high-voltage solar array - electrostatic discharge - sustained arc discharge - mechanism Supported by the National Laboratory of Vacuum, Cryogenics Technology and Physics (Grant No. 51475030504DZ2.01), and the National High Technology Development Program of china (Grant No. 2.02.A732.58)

关键词： high-voltage solar array electrostatic discharge sustained arc discharge mechanism

XPS Study of the Oxygen on A_2.O_4-type Compounds-A New Discovery of O_(1S) Peaks

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Chinese chemical Letters 1999年第12期10卷 0-0页

作者： Zhi MA Yong Ning QIN Xiao Zhou QI Fei HE(School of chemical Engineering and Technology, tianjin University, tianjin 300072. School of chemical Engineering and Technology Tianjin University

By means of XPS, a new O1s peak which reflects the lattice oxygen on A_2.O_4-typecompounds is discovered, suggesting that the lattice oxygen might have two energy states on thistype of material.

关键词： XPS lattice oxygen A_2.O_4-type compound.

Synthesis and Characterization of Dipeptide Schiff Base Complexes of Copper(Ⅱ), Zinc(Ⅱ), Nickel(Ⅱ) and Cobalt(Ⅱ)

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Chinese chemical Letters 1997年第6期8卷 557-558页

作者： Guang Bin WANG Jin Ling WANG Fang Ming MIAO (Institute of chemical Crystallography,tianjin Normal University. tianjin 300071) Inst. of chemical Crystallography Tianjin Normal University Tianjin 300071 China

A new Schiff base (LK) obtained from 2. 4, -dihydroxybenzaldehyde and glycly-DL- phenylalanine reacted with Cu(II), Zn(II), Ni(II) and Co(II) to yield new complexes. The complexes were characterized by elemental analyses, molar conductance, 1H NMR DTA, TG, IR and UV spectroscopy. In these complexes the ligand is coordinated to the metal through its phenolic oxygen, carboxyl oxygen, imino nitrogen and amide nitrogen. All complexes are non-electrolytes and four coordinated with 1:1(metal; ligand) stoichiometry. The probable structure of the complexes is suggested

关键词： Nickel Synthesis and Characterization of Dipeptide Schiff Base Complexes of Copper Zinc and Cobalt Base