界带分析的基本理论和计算方法

基于应用力学的辛数学理论,阐述了界带分析的基本理论与计算方法,主要包括:界带分析的基本概念、界带分析的变分原理、单个与不同原子周期链的波的色散关系、子结构界带分析计算方法以及数值算例等多方面内容。研究工作在表明辛数学理论优势和潜力的同时,也为相关问题的深入研究奠定了理论与算法基础。     

结构谐振动力响应的有限元、动凝聚、迁移子结构法

本文扩展了FETM法思想,结合子结构、动凝聚及Riccati变换理论,直接求解谐和激励下结构的受迫动力响应,从而节省了运行时间,严格控制了计算精度。本文编制了程序,并以振型叠加法运行结果为参照,对不同算例的运算效率作了比较。结果表明:本文方法在理论上、实践上是切实可行的。     

Chemical Modification and Energetically Favorable Atomic Disorder of a Layered Thermoelectric Material TmCuTe2 Leading to High Performance

Thermoelectric (TE) materials have continuously attracted interest worldwide owing to their capability of converting heat into electricity. However, discovery and design of new TE material system remains one of the greatest difficulties. A TE material, TmCuTe₂, has been designed by a substructure approach and successfully synthesized. The structure mainly features CuTe₄‐based layers stacking along the c axis that are separated by Tm³⁺ cations. Such an intrinsic Cu site vacancy structure undergoes a first‐order phase transition at around 606 K driven by the energetically favorable uniform Cu atom re‐distribution on the covalent CuTe₄‐based layer substructure, as shown by crystal structure simulations and variable‐temperature XRD data. Featured with very low thermal conductivity (ca. 0.6 W m^?1 K^?1), large Seebeck coefficient (+185 μV K^?1), and moderate electrical conductivity (220 S cm^?1), TmCuTe₂ has a maximum ZT of 0.81 at 745 K, which is nine times higher than the value of 0.09 for binary Cu₂Te, thus making it a promising candidate for mid‐temperature TE applications. Theoretical studies uncover the electronic structure modifications from the metallic Cu₂Te to the narrow gap semiconductor TmCuTe₂ that lead to such a remarkable performance enhancement.     

循环对称结构的模态参数计算方法

利用循环对称结构部件模态的等同性，推求了循环对称结构中的混合型动态子结构法的综合方程。     

分析层状半空间对入射地震波响应的改进模型

采用层内位移线性近似的薄层元及基岩半空间刚度的Ｔａｙｌｏｒ级数展开技术，利用基岩地震动三分量反算入射波振幅，建立了层状半空间场地地震波响应分析的一种改进模型，分析了层状半空间对倾斜入射ＳＨ，ＳＶ和Ｐ波的动力响应．结果表明，本文模型不仅具有较高精度，而且非常便于数值处理和计算机编程     

Deformation and properties of heterophase metastable steels under high hydrostatic pressures

Abstract

This paper shows the possibility to control the strength and plasticity properties of heterophase metastable steels based on the Fe-Mn solid solution as a result of purposeful alteration of the phase composition and fault structure by varying the hydroextrusion process parameters. Practical means of realization of high-strength states (б_0.2 ? 1000… 1400 MPa) in 05G20S2 and I4G20K2F steels using the hydroextrusion are proposed.     

Finitely generated submodels of an uncountably categorical homogeneous structure

We generalize the result of non‐finite axiomatizability of totally categorical first‐order theories from elementary model theory to homogeneous model theory. In particular, we lift the theory of envelopes to homogeneous model theory and develope theory of imaginaries in the case of ω‐stable homogeneous classes of finite U‐rank. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Identification of a chemical substructure that is immobilized to ferrite nanoparticles (FP)

Despite the wide utility of ferrite nanoparticles (FP), a methodology to conjugate heterologous molecules to FP is still limited and characterization of small molecule-conjugated FP is not well known. Here, we describe what kinds of proteins and amino acids are selectively immobilized onto FP when FP is synthesized in the presence of these molecules. Two-dimentional gel electrophoresis (2D SDS-PAGE) showed that proteins with low pI value were selectively bound to FP. Quantitative analyses using HPLC suggested that L-aspartic acid (Asp) and L-cysteine (Cys) were bound to FP selectively among natural amino acids examined. Additional analysis of compounds-conjugated FP revealed that selective binding of Asp to FP was attributed with its molecular structure. It was found that the substructure of amino acid-bound to FP specifically was composed of a defined chelation of two carboxyl groups separated by two carbon atoms as deduced from FT-IR measurement. Thus, we concluded that molecules possessing two carboxyl groups separated by two carbons were bound to FP spontaneously and selectively, which might enable the attachment of free functional groups onto the FP surface if their molecules have functional groups other than carboxyl groups. The resulting complex might be applicable as a chemical tag to immobilize various molecules onto FP.     

Cheminformatics analysis and learning in a data pipelining environment

Summary Workflow technology is being increasingly applied in discovery information to organize and analyze data. SciTegic's Pipeline Pilot is a chemically intelligent implementation of a workflow technology known as data pipelining. It allows scientists to construct and execute workflows using components that encapsulate many cheminformatics based algorithms. In this paper we review SciTegic's methodology for molecular fingerprints, molecular similarity, molecular clustering, maximal common subgraph search and Bayesian learning. Case studies are described showing the application of these methods to the analysis of discovery data such as chemical series and high throughput screening results. The paper demonstrates that the methods are well suited to a wide variety of tasks such as building and applying predictive models of screening data, identifying molecules for lead optimization and the organization of molecules into families with structural commonality.     

Identification of target-specific bioisosteric fragments from ligand–protein crystallographic data

Bioisosteres are functional groups or atoms that are structurally different but that can form similar intermolecular interactions. Potential bioisosteres were identified here from analysing the X-ray crystallographic structures for sets of different ligands complexed with a fixed protein. The protein was used to align the ligands with each other, and then pairs of ligands compared to identify substructural features with high volume overlap that occurred in approximately the same region of geometric space. The resulting pairs of substructural features can suggest potential bioisosteric replacements for use in lead-optimisation studies. Experiments with 12 sets of ligand–protein complexes from the Protein Data Bank demonstrate the effectiveness of the procedure.