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PREDICTION OF ThE MIXING ENThALPIES OF BINARY LIQUID ALLOYS BY MOLECULAR INTERACTION VOLUME MODEL

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Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 336-340页

作者： h.W. yang D.P. Tao z.h. zhou Faculty of Materials and Metallurgical Engineering Kunming University of Science and Technology Kunming 650093 China

The mixing enthalpies of 23 binary liquid alloys are calculated by molecular interaction volume model （MIVM）, which is a two-parameter model with the partial molar infinite dilute mixing enthalpies. The predicted va... 详细信息

关键词： Molecular interaction volume model Mixing enthalpy Liquid alloys Prediction

Calculation of Collective Variable-based PMF by Combining WhAM with Umbrella Sampling

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Chinese Physics Letters 2012年第6期29卷 291-294页

作者： XU Wei-Xin LI yang zhANG John z.h. State Key Laboratory of Precision Spectroscopy Department of PhysicsEast China Normal UniversityShanghai 200062 Institute of Theoretical and Computational Science Institutes for Advanced Interdisciplinary ResearchEast China Normal UniversityShanghai 200062 Department of Chemistry New York UniversityNew YorkNew York 10003USA

Potential of mean force (PMF) with respect to localized reaction coordinates (RCs) such as distance is often applied to evaluate the free energy profile along the reaction pathway for complex molecular ***,calculation of PMF as a function of global RCs is still a challenging and important problem in computational *** examine the combined use of the weighted histogram analysis method and the umbrella sampling method for the calculation of PMF as a function of a global RC from the coarse-grained Langevin dynamics simulations for a model *** method yields the folding free energy profile projected onto a global RC,which is in accord with benchmark *** this method rare global events would be sufficiently sampled because the biased potential can be used for restricting the global conformation to specific regions during free energy *** strategy presented can also be utilized in calculating the global intra- and intermolecular PMF at more detailed levels.

关键词： coordinates utilized calculating

An efficient method for computing excess free energy of liquid

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Science China Chemistry 2018年第1期61卷 135-140页

作者： Jianing Song Linqiong Qiu John z.h. zhang School of Chemistry and Molecular Engineering East China Normal University Shanghai 200062 China NYU-ECNU Center for Computational Chemistry at NYU ShanghaL Shanghai 200062 China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai 200062 China Department of Chemistry New York University NY NY 10003 USA

We present a new theoretical method for efficient calculation of free energy of liquid. This interaction entropy method allows one to compute entropy and free energy of liquid from standard single step MD(molecular dynamics) simulation directly in liquid state without the need to perform MD simulations at many intermediate states as required in thermodynamic integration or free energy perturbation methods. In this new approach, one only needs to evaluate the interaction energy of a single(fixed) liquid molecule with the rest of liquid molecules as a function of time from a standard MD simulation of liquid and the fluctuation of distribution of this interaction energy is then used to calculate the interaction entropy of the liquid. Explicit theoretical derivation of this interaction entropy approach is provided and numerical calculations for the benchmark liquid water system were carried out using three different water models. Numerical analysis of the result was performed and comparison of the computational result with experimental data and other theoretical results were provided. Excellent agreement of calculated free energies with the experimental data using TIP4 P model is obtained for liquid water.

关键词： excess free energy liquid MD simulation interaction entropy

First-principles Calculation Assisted Thermodynamic Modeling of Ti-Co-Cu Ternary System

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Journal of Materials Science & Technology 2010年第4期26卷 317-326页

作者： Y.J. yang X.M. Tao W.J. zhu z.h. Long h.S. Liu z.P. Jin School of Materials Science and Engineering Central South University Changsha 410083 China Key Lab of Non-ferrous Metal Science and Engineering Ministry of Education Changsha 410081 China

Thermodynamic assessment of Ti-Co-Cu ternary system has been carried out by combining first-principle calculation and CALPhAD method. Firstly, formation enthalpies of stable and hypothesized compounds were calculated by first-principles method. Then, based on reported experimental information, a thermodynamic description of the Ti-Co-Cu ternary system was performed. Solution phases were treated as substitutional solutions of which excess Gibbs energies were formulated by Redlich-Kister polynomial, and the intermediate phases were described with sublattice models. All measured isothermal sections were reasonably reproduced. In addition, liquidus projection of this ternary system was further calculated, which may be useful for relevant materials processing.

关键词： First-principle CALPhAD Thermodynamic modeling

Interaction specific binding hotspots in Endonuclease colicin-immunity protein complex from MD simulations

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Science China Chemistry 2013年第8期56卷 1143-1151页

作者： YAO XueXia JI ChangGe XIE DaiQian zhANG John z.h. School of Chemistry and Chemical Engineering Nanjing University College of Engineering Nanjing Agricultural University State Key Laboratory of Precision Spectroscopy Department of PhysicsEast China Normal University Department of Chemistry New York University

The binding of Endonuclease colicin 9 (E9) by Immunity protein 9 (Im9) was found to involve some hotspots from helix III of Im9 on protein-protein interface that contribute the dominant binding energy to the *** the current work,MD simulations of the WT and three hotspot mutants (D51A,Y54A and Y55A of Im9) of the E9-Im9 complexes were carried out to investigate specific interaction mechanisms of these three hotspot *** changes of binding energy between the WT and mutants of the complex were computed by the MM/PBSA method using a polarized force field and were in excellent agreement with experiment values,verifying that these three residues were indeed hotspots of the binding *** decomposition analysis revealed that binding by D51 to E9 was dominated by electrostatic interaction due to the presence of the carboxyl group of Asp51 which hydrogen bonds to *** binding by hotspots Y54 and Y55,van der Waals interaction from the aromatic side chain of tyrosine provided the dominant *** comparison,calculation by using the standard (nonpolarizable) AMBER99SB force field produced binding energy changes from these mutations in opposite direction to the experimental *** hydrogen bond analysis showed that conformations sampled from MD simulation in the standard AMBER force field were distorted from the native state and they disrupted the inter-protein hydrogen bond network of the protein-protein *** current work further demonstrated that electrostatic polarization plays a critical role in modulating protein-protein binding.

关键词： protein-protein interaction binding hotspot mutation Endonuclease Colicin immunity protein MD simulation

Structure and Magnetic Properties of S-doped Mn_3O_4/S Composited Nanoparticles and Mn_3O_4 Nanoparticles

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Journal of Materials Science & Technology 2011年第6期27卷 503-506页

作者： X. he z.h. Wang D.Y. Geng z.D. zhang Shenyang National Laboratory for Materials Science Institute of Metal Research and International Centre for Materials Physics Chinese Academy of Sciences Shenyang 110016 China

Composited nanoparticles,consisting of Mn3O4,S-doped Mn3O4 and S,were synthesized by co-precipitation reaction and Mn3O4 nanoparticles were then obtained after removing the pure S from the composited *** Mn3O4-type phase with larger lattice constant a was formed by doping *** fixed temperatures below Curie temperature（TC）,the magnetization of the S-doped Mn3O4/S composited nanoparticles was smaller than that of the Mn3O4 *** blocking temperature was 36.3 and 34.8 K for Sdoped Mn3O4/S composite and Mn3O4 nanoparticles,*** anisotropy field of S-doped Mn3O4/S composite was determined to be about 55.3 kOe.

关键词： Nanostructured materials Chemical synthesis X-ray diffraction Magnetic measurements

Application of Neural Network in Precision Prediction of hat-Section Profiles in Rotary Draw Bending

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Journal of Materials Science & Technology 2001年第1期17卷 137-138页

作者： Li, X.C. yang, Y.Y. Jin, z.h. Liu, J.T. Li, S.P. harbin Inst. of Technol. Harbin 150001 China

It is difficult to control the accuracy of hat-section profile rotary-draw bent products because their shapes are complex and many factors influence the forming process. A multi-layer feed-forward neural network based on improved BP (back propagation) algorithm is adopted to study the influence law of the main material properties and forming parameters on the accuracy of hat-section profile forming process. The prediction of rotary draw-bending precision is realized and the technology parameters in the forming process are controlled according to the given precision.

关键词： Application of Neural Network in Precision Prediction of hat-Section Profiles in Rotary Draw Bending

EFFECT OF LOW-FREQUENCY ELECTROMAGNETIC FIELD ON ThE AS-CASTING MICROSTRUCTURES AND MEChANICAL PROPERTIES OF hDC 2024 ALUMINUM ALLOY

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 205-210页

作者： Q.F. zhu z.h. zhao J.z. Cui Y.B. zuo F. Qu Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern Univer- sity Shenyang 110004 China

The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were produced by the conventional horizontal chill casting process and low frequency electromagnetic horizontal chill casting processre- spectively. The as-cast structures and the mechanical property of the ingots were examined. The results showed that the low frequency electromagnetic field could sub- stantially refine the microstructures and pronouncedly reduce the macrosegregation in the horizontal direct chill casting process. Moreover, the surface quality of the ingot was prominently improved by the low frequency electromagnetic field. The fracture strength and elongation percentage of the ingot was increased with the low frequency electromagnetic field.

关键词： horizontal direct chill casting Low frequency electromagnetic field 2024 aluminum alloy Microstructures Macrosegregation

ANALYSIS OF TEMPERATURE DEPENDENCE OF PhASES AND SURFACE MORPhOLOGY OF Bi_2Sr_2Ca_(x-1)Cu_xO_y ThIN FILMS USING REACTIVE CO-DEPOSITION METhOD

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Acta Metallurgica Sinica(English Letters) 2007年第3期20卷 199-204页

作者： z.h. zou X.M. Yu B.S. zhang Y. Qi School of Science Northeastern University Shenyang 110004 China

A reactive co-deposition processing for obtaining high-quality single-phase Bi2Sr2Cax-1CuxOy （Bi2212） thin films has been investigated using molecular beam epitaxy （MBE） with 2.7 ×10^-3pa ozone gas introduction for oxidation. The thin films with a constant composition of almost 2 ： 2 ： 1 ： 2 were designed to be fabricated at the substrate temperature between 675 and 780℃, the substrate temperature dependence of the surface morphology and the emergence phases were investigated in detail. A noticeable result is that the distribution of Cu element in the thin films is sensitively changed with the substrate temperature. At 750℃ it is inclined to locate in the periphery of each grain through the diffusion process. At 780℃ the Cu-compositional fluctuation brought around the dendritic crystal growth in the thin films. Below 705℃, the Bi2212 single-phase cannot be achieved in the thin films.

关键词： Bi2212 (Bi2Sr2Cax-1CuxOy) single-phase dendritic growth substrate temperature