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Predicting neutron star spins from twin kHz QPOs

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science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 247-248页

作者： SHI ChangSheng Department of Astronomy,Nanjing university,Nanjing 210093,china college of material science and chemical engineering,hainan university,hainan 570228,china 1. Department of Astronomy Nanjing University Nanjing 210093 China

We briefly review the proposed relations between the frequencies of twin kilohertz quasi-periodic oscillations(kHz QPOs) and the spin frequencies in neutron star low-mass X-ray binaries(NSLMXBs).To test the validity of the proposed models,we estimate the spin frequencies under these theoretical relations and compare them with the measured *** seems that magnetohydrodynamic(MHD) oscillations are more promising to account for the kHz QPOs.

关键词： win kHz QPOs spin neutron stars LMXBs

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION

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Chinese Journal of Polymer science 2000年第1期18卷 57-67页

作者： Yan Pan Rong-shi Cheng college of material science and engineering, South china university of Technology, Guangzhou 510641, china college of Chemistry and chemical engineering, Nanjing university, Nanjing 210093, china S china Univ Technol Coll Mat Sci & Engn Guangzhou 510641 Peoples R China Nanjing Univ Coll Chem & Chem Engn Nanjing 210093 Peoples R China

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration C-s(dynamic contact concentration) which divides the dilute polymer solution into two regions.

关键词： self-association polymer solution viscosity concentration dependence

Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

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science china(Technological sciences) 2007年第6期50卷 807-814页

作者： SONG YuePeng1,2, LIU GuoQuan2, LI ZhiLin3, FENG ChengMing1 1 Mechanical and Electronic engineering college, Shandong Agricultural university, Tai’an 271018, china 2 college of materials science and engineering, university of science and Technology, Beijing 100083, china 3 college of material science and engineering, Beijing university of chemical Technology, Beijing 100029, china Mechanical Electronic engineering college Shandong Agricultural University Tai’an 271018 China college of materials science engineering University of Science Technology Beijing 100083 China college of material science engineering Beijing University of Chemical Technology Beijing 100029 China

By introducing the distribution probability of structural units in austenite contain- ing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and ex- perimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indi- cate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite.

关键词： multiplying factor (the quenching capability factor), empirical electron theory of solids and molecules, transformation effect coefficient of alloying elements, structural units in austenite containing alloying elements

PERFORMANCE AND INITIATION MECHANISM OF ISOPROPYLTHIOXANTHONE IN SURFACE PHOTOGRAFTING

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Chinese Journal of Polymer science 2000年第5期18卷 431-435页

作者： Wan-tai Yang Mei-zhen Yin Yu-feng Sun college of material science and engineering, Beijing university of chemical Technology, Beijing 100029, china Beijing Univ Chem Technol Coll Mat Sci & Engn Beijing 100029 Peoples R China

In a polymerization model with low density polyethylene (LDPE) as the substrate and acrylic acid (AA) as the monomer, the performance of isopropylthioxanthone (ITX) in initiating surface photografting polymerization was evaluated. The results show that the reactivity of photopolymerization and photografting of ITX locate between benzophenone (BP) and benzildimethylketal (BDK) for polymerization, BDK > ITX > BP; for surface grafting polymerization, BP > ITX > BDK. These results can be explained by a reaction mechanism of the inter-molecular or intra-molecular hydrogen abstraction reaction of ITX.

关键词： photografting polymerization photopolymerization hydrogen abstraction reaction

Analysis of variance for testing method of cement in determination of strength

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Progress in Natural science:materials International 2011年第4期21卷 341-346页

作者： Hong HUANG,Xiao-dong SHEN State Key Laboratory of materials-Oriented chemical engineering,college of material science and engineering, Nanjing university of Technology,Nanjing 210009,china State Key Laboratory of materials-Oriented chemical engineering College of Material Science and Engineering Nanjing University of Technology Nanjing 210009 China

The statistical tools such as descriptive statistics,full factorial design and analysis of source of variation were used to identify the potential factors that impact the validity of testing method for determining the strength of *** results showed that personal error impacted both accuracy and precision of test *** time associated with temperature fluctuation resulted in strength variation but did not impact the precision of test in all curing *** compactions did not impact the precision of test but resulted in the strength variation on 3 d and 28 d *** methods for the initial moist air curing significantly impacted the precision of testing method and resulted in the strength variation of cement on 1 d.

关键词： testing method of cement analysis of variance strength accuracy precision

Statistical study of cement additives with and without chloride on performance modification of Portland cement

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Progress in Natural science:materials International 2011年第3期21卷 246-253页

The effectiveness of cement additives with and without chloride on the fluidity and the strength development of Portland cement was compared by using statistical full factorial *** experimental results show that the cement additive containing CaCl2and Ca(NO3)2can enhance early strength of cement ***,Ca(NO3)2is less effective than CaCl2even if it is combined with other organic chemicals such as alkanolamine and *** significant difference is found between CaCl2and Ca(NO3)2influencing the fluidity and 28 d strength of *** fluidity is determined by saccharide and its interaction with *** 28 d strength enhancement is determined by *** fluidity as well as the mechanical performance of treated cement can be significantly improved by combining Ca(NO3)2with TIPA and saccharide.

关键词： Portland cement cement additive accelerator type fluidity strength development full factorial design

Manufacturing Technology of Refractory Metal Parts Based on SLS Rapid Prototyping

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稀有金属材料与工程 2011年第S4期40卷 257-260页

作者： Liu Bin,Bai Peikang,Ding Erming college of material science and engineering,North university of china,Taiyuan 030051,china N Univ china Coll Mat Sci & Engn Taiyuan 030051 Peoples R China

A rapid prototyping process of selective laser sintering (SLS) which can be used to refractory metal parts manufacturing is introduced in this *** material of polymer-coated Mo powder is prepared by coating polymer and freezing grinding *** laser sintering process has been experimentally researched,and optimized parameters have been *** post treatment process of prototyping parts has been developed,which is sintering framework-Mo by high temperature combining with Cu impregnation *** last,refractory metal parts of Mo/Cu composites are *** graph shows that Mo and Cu are close jointed together,and these phases distribute interlocked Mechanical and thermal properties of the material have been tested,concluding tensile strength(470 MPa),elastic modulus(267.8 GPa),elongation(15%),linear expansion(5.5×10-6/K).The technology can be applied to manufacturing fire-resisting parts of weaponry and aerospace arms,as well as conductance and cooling elements used to electronics industry.

关键词： refractory metal parts polymer-coated Mo powder selective laser sintering post treatment

Study on BaTiO_3 films prepared by AC power microarc oxidation

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science china(Technological sciences) 2009年第8期52卷 2195-2199页

作者： HUANG WenBo, LI WenFang & HAN Bing college of material science and engineering, South china university of Technology, Guangzhou 510640, china 1. college of material science and engineering South China University of Technology Guangzhou 510640 China

BaTiO3 films were prepared by microarc oxidation (MAO) with an in-house built alternating current (AC) power supply in Ba(OH)2 solution in this study. The surface morphology, combinability with the substrate and phase composition of the films were investigated by XRD, SEM and TEM. The BaTiO3 films were annealed at a temperature range of 900 to 1200℃ and phase compositions were tested thereafter. The results showed that the BaTiO3 films were mainly composed of the primitive hexagonal phase with relatively small amount of tetragonal and amorphous phases. Moreover, the amount of amorphous phase decreased with the time of annealing. The transformation of BaTiO3 from hexagonal structure to tetragonal stucture became obvious until the annealing temperature reached 1200℃. The film consisted mainly of BaTiO3 tetragonal structure with ferroelectric property. The influence of annealing on surface morphology and mechanism of phase transformation of the films were also discussed.

关键词： microarc oxidation ferroelectric film BaTiO3 annealing phase composition

Preparation of nanocrystalline BaTiO_3 ceramics

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science china(Technological sciences) 2009年第6期52卷 1730-1734页

作者： DENG XiangYun1,2,LI DeJun1,LI JianBao2,WANG XiaoHui3 & LI LongTu3 1 college of Physics and Electronic Information,Tianjin Normal university,Tianjin 300387,china 2 materials and chemical engineering Institute,Key Laboratory for hainan Advantage Resources and Applied Technology in chemical engineering material of Ministry of Education,hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti,hainan university,Haikou 570228,china 3 Department of materials science and engineering,Tsinghua university,Beijing 100084,china college of Physics and Electronic Information Tianjin Normal University Tianjin 300387 China materials and chemical engineering Institute Key Laboratory for Hainan Advantage Resources and Applied Technology in Chemical Engineering Material of Ministry of Education Hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti Hainan University Haikou 570228 China Department of materials science and engineering Tsinghua University Beijing 100084 China

The high-dense nanocrystalline BaTiO3(BT)ceramics with grain size smaller than 100nm have been successfully prepared by the two step sintering and the spark plasma sintering(SPS)*** successive transitions in nanograin BT ceramics from rhombohedral to orthorhombic,tetragonal and cubic transitions,similar to those in coarse BT ceramics,were revealed by in-situ temperature dependent Raman *** multiphase coexistence and the diffused phase transition character were demonstrated in the 8nm nanocrystalline BT ceramics.

关键词： nanocrystalline BaTiO3 ceramics preparation microstructure size effect