QtUCP-A program for determining unit-cell parameters in electron diffraction experiments using double-tilt and rotation-tilt holders

A computer program, QtUCP, has been developed based on several well-established algorithms using GCC 4.0 and Qt (R) 4.0 (Open Source Edition) under Debian GNU/Linux 4.0r0. it can determine the unit-cell parameters from an electron diffraction tilt series obtained from both double-tilt and rotation-tilt holders. In this approach, two or more primitive cells of the reciprocal lattice are determined from experimental data, in the meantime, the measurement errors of the tilt angles are checked and minimized. Subsequently, the derived primitive cells are converted into the reduced form and then transformed into the reduced direct primitive cell. Finally all the patterns are indexed and the least-squares refinement is employed to obtain the optimized results of the lattice parameters. Finally, two examples are given to show the application of the program, one is based on the experiment, the other is from the simulation. (C) 2008 Elsevier B.V. All rights reserved.

Structure and magnetic properties of ScFe6Ga6-type RCo5Ga7 (R = Y, Tb, Dy, Ho and Er)

The structure and magnetic properties of the RCo5Ga7 (R = Y, Tb, Dy, Ho and Er) compounds with the ScFe6Ga6-type structure have been studied. The stability of RCo5Ga7 is closely related with the ratio of the metal radii R-RE/R-(Co,R-Ga). With R-RE/R-(Co,R-Ga) less than or equal to 1.36, the compounds can be stabilized in the ScFe6Ga6-type structure. The lattice of RCo5Ga7 shrinks as the atomic order of R increases, and it is consistent with the lanthanide contraction. The structure analysis based on X-ray diffraction patterns reveals that in the orthorhombic RCo5Ga7 (Immm), R occupies the 2a site, and Co enters into the 8k and the 4h sites, and Ga is at the 4e, 4f, 4g, 4h and 8k sites. The interatomic distances and the coordination numbers of RCo5Ga7 are provided from the refinement results. The short interatomic distance (less than 2.480 Angstrom) between the Co ions results in the negative magnetic interaction, which does not favor ferromagnetic ordering. The magnetic moment of YCo5Ga7 is absent, and RCo5Ga7 (R = Tb, Dy, Ho and Er) may have long-range magnetic ordering with the paramagnetic Curie temperature lower than 5 K. (C) 2004 Elsevier Inc. All rights reserved.

超图多级划分算法框架及对划分结果的多阶段优化

超图划分应用于大规模矩阵计算、大规模集成电路等领域.详细地阐述了超图多级划分的算法框架,并提出对划分结果进行优化的一种手段,通过进行多阶段的V循环优化,在可以接受的运行时间内得到对超图的一个较优的划分.

一种改进的数据求精证明规则

提出一种改进的数据求精规则，并用关系模式进行描述。引入全局状态来描述程序所有可能的输入和输出，允许非平凡的初始化，允许前向模拟和后向模拟，能应用于消除具体模型的不确定性晚于消除抽象模型的不确定性的情况。并用实例说明了在Isabelle定理证明器中规则的应用方法。

多粒度多维度软件过程度量和改进方法研究

随着软件对社会各领域、各层次的渗透，软件逐渐转变为一种对社会团体、 甚至对社会公众的服务，软件的规模越来越大、用户需求越来越多、功能和性能 要求也越来越复杂。因此，对软件的可用性、可靠性、可信性等质量要求不断提 高。伴随着软件业的逐渐发展，软件过程技术逐渐被应用于软件产品的开发当中。 “质量形成于产品的生产过程”这一理念逐渐被软件组织所接受。其核心思想体 现在通过对软件过程的策划、控制和改进来保证软件产品的质量，进而提高软件 组织的经营业绩。软件过程度量作为软件过程管理和过程改进的关键活动，越来 越为软件组织所重视。 通过实施过程管理，能够刻画项目或过程目标的满足程度，找到造成过程 或产品重大偏差的根本原因，进而实施过程改进。然而，在软件过程度量实施期 间，软件组织面对不同的软件开发过程、众多的过程性能度量指标、复杂的统计 分析方法，既要考虑量化管理方法的合理性和复杂程度，又要权衡量化管理的实 施成本，这使得实施有效的过程度量充满挑战。本文基于经验软件工程方法，提 出一种多粒度多维度软件过程度量框架，以及实现该框架的关键技术：软件过程 性能基线的建立和维护方法；同时介绍了该框架下的软件项目进度量化控制模 型，支持软件组织实施有效的过程管理和改进。 本文的主要贡献包括： 提出了一种多粒度多维度软件过程度量框架(Multi-granularity Multi-dimensional software Process Measurement Framework，M2-PMF)，该框架通 过综合考虑软件过程管理和改进的必要信息所属的特征维度和软件组织的过程 管理粒度，自底向上的通过实体层、度量分析层和目标层指导软件组织建立一套 可以覆盖软件全生命周期的、开放的、支持过程改进的综合指标体系和模型。支 持软件组织裁减和定制确定环境下的度量体系，清晰了解其软件过程能力和性 能，提高软件组织对软件过程的控制能力，保障软件开发过程和软件产品的质量。 提出了基于统计分析的过程性能基线的建立和改进方法（Baseline – Statistic - Refinement， BSR），该方法可以有效地建立和维护过程性能基线，支持软件 组织从定性管理提升到定量管理。该方法应用波动图，在过程尚不稳定、数据样 本不足的情况下尽可能多的获得过程改进信息，识别过程改进机会，确定过程改 进途径，帮助软件组织高效地改进其过程中明显的弱项。在过程逐步稳定之后， 利用控制图、排列图、因果图、散点图等统计工具，分析过程性能，建立过程性 多粒度多维度软件过程度量和改进方法研究 ii 能基线，并不断精化。 在M2-PMF 框架下，提出了基于统计过程控制（Statitical Process Control， SPC）和挣值管理（Earned Value Management，EVM）的项目进度量化控制模型 SEVM，该方法通过对项目进度指数的统计控制，分析其稳定性，并通过估算模 型，根据项目当前挣值数据推算项目总进度偏差，并加以控制。支持软件组织对 项目进度进行量化控制，提高了项目按期交付的可能性。 最后，介绍了本文提出的过程度量框架和量化管理方法在国内多家软件组 织中的实际应用。应用案例表明，本文的方法和模型具有广泛的适应性和高度的 可操作性。应用本文方法能够对项目进行有效的估算、度量和控制，进而提高产 品质量并改善客户满意度。

超图多级划分算法框架及对划分结果的多阶段优化

超图划分应用于大规模矩阵计算、大规模集成电路等领域.详细地阐述了超图多级划分的算法框架,并提出对划分结果进行优化的一种手段,通过进行多阶段的循环优化,在可以接受的运行时间内得到对超图的一个较优的划分.

Influence of processing temperature on microstructure and microhardness of copper subjected to high-pressure torsion

Cu samples were subjected to high-pressure torsion (HPT) with up to 6 turns at room temperature (RT) and liquid nitrogen temperature (LNT), respectively. The effects of temperature on grain refinement and microhardness variation were investigated. For the samples after HPT processing at RT, the grain size reduced from 43 mu m to 265 nm, and the Vickers microhardness increased from HV52 to HV140. However, for the samples after HPT processing at LNT, the value of microhardness reached its maximum of HV150 near the center of the sample and it decreased to HV80 at the periphery region. Microstructure observations revealed that HPT straining at LNT induced lamellar structures with thickness less than 100 nm appearing near the central region of the sample, but further deformation induced an inhomogeneous distribution of grain sizes, with submicrometer-sized grains embedded inside micrometer-sized grains. The submicrometer-sized grains with high dislocation density indicated their nonequilibrium nature. On the contrary, the micrometer-sized grains were nearly free of dislocation, without obvious deformation trace remaining in them. These images demonstrated that the appearance of micrometer-sized grains is the result of abnormal grain growth of the deformed fine grains.

千金子和暖地大叶藓的化学成分研究

本论文由三部分共4 章组成。第一部分阐述了大戟科大戟属传统中药千金子（Euphorbia lathyris L.）化学成分、生物学活性以及千金子化学成分的HPLC、UPLC-MS、GC-MS 分析成果。第二部分介绍了民族药材暖地大叶藓（Rhodobryum giganteum (Schwaegr.) Par.）的化学成分研究和结构鉴定。第三部分概述了大戟属 植物中大环二萜酯的研究进展。 第一章包括1－3 节。在第1, 2 节中报道了千金子（Euphorbia lathyris L.）95% 乙醇提取物的化学成分分离鉴定。我们采用正、反相硅胶柱层析、重结晶等各种分离方法，凭借MS、IR、NMR、X-ray 等现代仪器手段,从中共分离鉴定22 个化合物。其中8 个是高活性化合物前体-续随子烷型大环二萜及3 个巨大戟烷型二萜，还有香豆素、生物碱、甾体等类型，其中完成对5 个大环二萜酯构型的确认，对2 个二萜酯构型进行了修正。第3 节中介绍对千金子化学成分的细胞毒性、α-葡萄糖苷酶抑制活性、P-gp 表达抑制活性的模型筛选结果。 第二章包括3 节，第1 节报道不同产地千金子高效液相色谱定量分析结果。第2 节介绍了各大环二萜酯的HPLC-MS/MS 的分析结果，并且对其质谱裂解规律、UPLC-MS 快速鉴定方法做了进一步讨论。第3 节介绍了千金子挥发油成分分析。采用传统水蒸气蒸馏方法提取千金子中的挥发油，并经气相色谱－质谱联用（GC-MS）技术共分离鉴定出 49 个化合物，占挥发油总量的90.48％。 第三章包括1, 2 两节，第1 节报道了暖地大叶藓化学成分。采用正、反相硅胶，凝胶柱层析等各种分离方法和MS、IR、NMR 等解析手段，共分离鉴定10个化合物，其中一个环肽化合物为新化合物。第2 节介绍了暖地大叶藓挥发油成分分析，共分离鉴定出 52 个化合物，占其挥发油总量的85.67％。 第四章概述了大戟科大戟属植物中大环二萜酯的研究进展。 This dissertation consists of three parts. In the first part, it is elaborated that the phytochemical investigation from the traditional Chinese medicine: seeds of Euphorbia lathyris L.. Biological activity and constituents analysis by HPLC、UPLC-MS、GC-MS were reported. In the second part, it is discussed that the chemical constituents were isolated and identificated from minority nationalitical herb－Rhodobryum giganteum (Schwaegr.) Par.. The third part is a review about the progress of studies on macrocyclic diterpenes from Euphorbia. The first part is composed of 1－3 sections. The section 1and 2 is focused on the isolation and identification of chemical constituents from seeds of E. lathyris. 22 compounds were isolated from the seeds of E. lathyris. by isolation methods of column chromatography (silica gel, including reversed phase) and recrystallisation on the basis of spectroscopic methods including IR, MS, NMR and X-ray. In 8 macrocyclic and 3 ingenane diterpenes, the relative configuration of 5 macrocyclic diterpenes were confirmed, in which 2 were amended. In the third section, cell cytotoxic activity, restraining activity of α-Glucosidase and multidrug resistance (MDR) reversing activity about P-gp were tested. 5 potential revsering reagents were found. The second part is composed of 1－3 sections. In first section it is described that the quality of the chemical constituents of E. lathyris from 5 sources , which were analyzed by high-performance liquid chromatography. In addition, the fractionation rules of some macrocyclic diterpenes were discussed and Ultra Performance Liquid Chromatography/ electrospray ionization mass spectrometry (UPLC-MS) was applied for quick determination of compounds in the second section. In the third section, chemical analysis of the essential oil from seeds of E. lathyris by GC-MS were reported. The essential oil from the seeds of E. lathyris L. in Sichuan was extracted by steam distillation and 49 compounds were isolated and identified from the essential oil by gas chromatography-mass spectrometer (GC-MS). These compounds are accounted for 90.46% of the total essential oil. The second part, including section 4 and 5, is about the phytochemical investigation of R. giganteum. In the former section, ten compounds were isolated and identified. Among them, a new peptide was characterized by spectroscopic analysis including IR, MS and NMR. In the other section, 52 compounds were isolated and identified from the essential oil by gas chromatography-mass spectrometer (GC-MS). These compounds are accounted for 85.67% of the total essential oil. The third part is a review about the progress of studies on macrocyclic diterpenes from Euphorbia.

Effects of rare earth on the structure and properties of Mg–6Zn–5Al–4Gd–1RE (RE = Ce or Y) alloys

The microstructures and mechanical properties of Mg-6Zn-5Al-4Gd-1RE (RE = Ce or Y) alloys were investigated. The addition of Ce or Y obviously refines the grain size for the Mg-6Zn-5Al-4Gd-based alloy, while the Y element has a better refining effect. The Ce and Y show different grain-refining mechanisms: Ce addition mostly promotes the growth of secondary dendrite, while Y addition mainly increases the heterogeneous nucleation sites.

Effects of cerium on the microstructure and mechanical properties of Mg–20Zn–8Al alloy

Mg-20Zn-8Al-xCe(x=0-2 wt.%) alloys were prepared by metal mould casting method, the effects of Ce on the microstructure and mechanical properties of the alloys were investigated. The results showed that the dendrite as well as gram size were refined by the addition of Ce, and the best refinement was obtained in 1.39% Ce containing alloy.

Crystal structure of microwave dielectric ceramics Ba[(Mg1-xCdx)(0.33)Nb-0.67]O-3

A series of complex perovskite solid solutions of Ba[(Mg1-xCdx)(0.33)Nb-0.67]O-3 have been synthesized by the columbite method. Detailed Rietveld refinement of their X-ray diffraction data show that Ba[(Mg1-xCdx)0(.33)Nb(0.67)]O-3 has an order trigonal structure. The ordering degree as determined by the B-site occupancies increases with the partial substitution of Cd for Mg.

Microstructures and mechanical properties of as-cast Mg–5Al–0.4Mn–xNd (x=0, 1, 2 and 4) alloys

Mg-5Al-0.4Mn-xNd (x=0, 1, 2 and 4wt.%) alloys were prepared by metal mould casting method. The microstructures and mechanical properties were investigated. The results demonstrated that Al11Nd3 phase was formed and mainly aggregated along the grain boundaries with the addition of Nd. Meanwhile, the grain sizes were greatly reduced with the increasing Nd content.