基于第一性原理的镁合金合金相及固溶体研究进展

镁合金作为轻质的金属材料,具有广阔的应用前景,发展先进镁合金已成为当前的研究重点之一。第一性原理计算为开发和设计新型镁合金提供了一种经济高效的方法。基于第一性原理方法,综述了镁合金合金相及固溶体的研究现状,主要对晶体结构、弹性常数、弹性模量及广义层错能等的第一性原理研究进行了介绍,讨论了合金元素以及相结构对镁合金力学性能的影响。阐明第一性原理计算方法在镁合金研究中的重要作用,为新型镁合金成分设计及开发高性能镁合金提供参考。     

The materials genome and CALPHAD

The mapping of the human genome is an important basis for the development of new medicals and medical treatments.Consequently,it has attracted tremendous research funding over the last decade.On June2011,the Materials Genome Initiative was announced by the US President Obama as collaboration on modeling and advanced materials databases.Unfortunately,the materials genome was given a rather vague definition in the announcement.However,the materials genome should be defined in analogy with biological genomes and one may then conclude that:at any moment,the performance of a specific material depends on its chemical composition(inherent property stored in its genome)and its environment(external interactions–processing–conditions during usage).The materials genome should thus be defined as a set of information encoded in the language of thermodynamics obtained by careful assessment of experimental data and quantum mechanical calculations from which certain conclusions about the material can be drawn.The CALPHAD databases contain the thermodynamic and kinetic properties of a materials system.Such databases allow the prediction of materials structure as well as its response to processing and usage conditions,and are major parts of integrated computational materials engineering.     

Experimental measurements and theoretical calculations of the atomic structure of materials with subangstrom resolution and picometer precision

Lattice defects are unavoidable structural units in materials and play an important role in determining material properties. Compared with the periodic structure of crystals, the atomic configurations of the lattice defects are determined by the coordinates of a large number of atoms, making it difficult to experimentally investigate them. In computational materials science, multiparameter optimization is also a difficult problem and experimental verification is usually required to determine the possibility of obtaining the structure and properties predicted by cal- culations. Using our recent studies on oxide surfaces as examples, we introduce the method of integrated aberra- tion-corrected electron microscopy and the first-principles calculations to analyze the atomic structure of lattice defects. The atomic configurations of defects were mea- sured using quantitative high-resolution electron micros- copy at subangstrom resolution and picometer precision, and then the electronic structure and dynamic behavior of materials can be studied at the atomic scale using the first- principles calculations. The two methods complement each other and can be combined to increase the understanding of the atomic structure of materials in both the time and space dimensions, which will benefit materials design at the atomic scale.     

仿生叠层复合材料的研究现状与发展

一些天然的生物材料在结构和性能上具有优异的匹配性 ,这些结构特征为人工合成复合材料提供了一些有益的启示 文中在分析某些天然生物材料的强韧化机理的基础上 ,系统地介绍了仿生复合材料尤其是叠层复合材料的仿生设计原理、制备方法、主要研究内容和现状 指出考虑工艺参数的影响 ,制备出材料并建立相关条件下的仿生模型 ,对材料在应用领域的发展具有积极意义     

High-throughput experimental tools for the materials genome initiative

The materials innovation infrastructure in the materials genome initiative(MGI)consists of three major components:computational tools,experimental tools,and digital data.This article will review experimental tools for high-throughput,high spatial resolution measurements of several materials properties such as elastic modulus,thermal conductivity,specific heat capacity,and thermal expansion.Application of these tools on compositionvarying samples such as diffusion multiples can be used to quickly and efficiently obtain composition–phase–structure–property relationships for materials property database establishment.They can also be used in conjunction with theoretical modeling to find and explain unusual effects to improve the predictability of models.More micron scale resolution experimental tools are in development.These high-throughput tools will be an essential part of MGI.     

封面人物简介—徐僖

徐僖院士,高分子材料科学家,中国科学院院士,我国高分子材料学科的奠基人之一。现任四川大学教授、高分子研究所所长,上海交通大学教授、高分子材料研究所所长。西南石油大学“油气藏地质及开发工程”国家重点实验室第二届学术委员会委员。《高分子材料科学与工程》、《油田化学》期刊主编。曾任《中国大百科全书·化工》高分子化工分支主编,《中国大百科全书·化学》高分子化学分支副主编,《材料科学技术百科全书》高分子材料分支主编。 徐僖教授长期从事高分子化学、高分子材料成型基础理论、高分子力化学、油田化学、辐射化学等领域的研究。早在20世纪50年代后期,他即致力于高分子力化学的研究。力化学是化学与力学交叉的学科,高分子力化学一般较多研究应力导致高分子材料性能下降与结构破坏,他则着重研究应力对高分子材料的正效应。美国著名力化学家R.S.Porter在其专著《Polymer Stress Reactions(Academic Press,New York,1979)》中摘录了徐僖教授20世纪60年代的全部研究成果。20世纪80年代,徐僖教授和他领导的科研群体通过超声作用合成了18种难以从其单体合成的嵌段/接枝共聚物,可用作不相容聚合物的增容剂,油、气田勘探开发用的化学品和金属冷加工润滑剂等新型高分子材料。研究成果“在超声作用下聚合物的降解和接枝（嵌段）共聚”被认为达到国际先进水平,获得1987年国家自然科学奖二等奖。徐僖教授在他长期从事的研究领域先后在国内外学术刊物上发表研究论文300余篇,撰写出版著作、译著4本,获国家发明专利28项。曾获国家自然科学奖、国家发明奖等20余项国家、部委、省级奖励以及高分子材料学科建设与高层次人才培养国家级优秀教学成果奖、何梁何利基金科学与技术进步奖、侯德榜化工科学技术奖成就奖等。曾被授予全国高等学校先进科技工作者、全国教育系统劳动模范、国防军工协作先进个人等称号。徐僖教授早已年逾八旬,却仍然辛勤工作在科研和教学第一线。他说：“我没有风烛残年之感,也没有仅能发挥余热的凄凉。我想到的是如何与国内同行、海外华人共同努力,树立我们中华民族在国际高分子材料科学领域在国际上的声誉和地位。”他的人生格言是“人生的乐趣在于无私奉献”。他最大的心愿是“中国人能在世界上普遍受到尊重”。     

A review of the large-scale production of carbon nanotubes: The practice of nanoscale process engineering

Carbon nanotubes (CNTs) are nanomaterials that have attracted great research interest because of their unique properties and promising applications. The controllable synthesis of CNTs is a precondition for their broad application. In this review, we consider nanoscale process engineering and assess recent progress in the mass production of ultra-long, inexpensive CNTs with good alignment as well as tunability in wall number and diameter for fundamental and engineering science applications across multiple scales. Cutting-edge nanoscale process engineering research in the areas of physics, chemistry, materials, engineering, ecology, and social science will allow us to obtain high added value and multi-functional advanced CNTs. The synthesis of CNTs with controllable chirality, good-alignment, and predetermined sizes and lengths still presents great challenges. Through multidisciplinary scientific research, advanced CNT-based materials will promote the development of a sustainable society.     

Computational thermodynamics,computational kinetics,and materials design

Computational thermodynamics, known as CALPHAD method when dawned in 1950s, aimed at cou- pling phase diagrams with thermochemistry by computa- tional techniques. It eventually evolves toward kinetic simulations integrated with thermodynamic calculations, i.e., computational kinetics, including diffusion-controlled phase transformation, precipitation simulation, and phase- field simulation. In the meantime, thermodynamic, mobility, and physical property databases for multi-component and multi-phase materials, served as basic knowledge for materials design, are critically evaluated by CALPHAD approach combining key experiments, first-principles cal- culations, statistic methods, and empirical theories. The combination of these computational techniques with their conjugated databases makes it possible to simulate phase transformations and predict the microstructure evolution in real materials in a foreseeable future. Further links to micro- and macro-scale simulations lead to a multi-scale compu- tational framework, and aid the search for the quantitative relations among chemistry, process, microstructures, and materials properties in order to accelerate materials devel- opment and deployment. This is a new route of materials and process design pursued by Integrated Computational Materials Engineering （ICME） and Materials Genome Ini- tiative （MGI）. This article presents a review on the basic theories and applications, the state of the art and perspective of computational thermodynamics and kinetics.     

数据科学范式下的钙钛矿结构铁电新材料研究

 材料基因组计划倡导预测式新材料研发理念，推进高通量数据生产和利用技术，关注材料全生命周期价值。因此，材料基因组计划的执行需要在材料科学系统工程的框架下，集成统一计算、实验和理论等研究方法，以数据科学新范式为牵引、协同运用实验观测、理论建模和计算仿真研究范式，最终建立相关材料体系的性能与材料基因（原子系统的组成与结构）、工艺参数与使役条件之间的量化关系和数据库，实现新材料的按需设计和应用。本文在简单探讨科学研究范式、材料基因组计划和材料科学系统工程基本概念和方法的基础上，以钙钛矿结构氧化物铁电压电材料研究为例，探讨了数据科学范式下的新材料研究实践。结果表明，数据挖掘驱动的新材料设计确实可以降低探索时间和实验任务，加快新材料的发现和应用进程。     

Malaria research in the post-genomic era

For many pathogens the availability of genome sequence, permitting genome-dependent methods of research, can partially substitute for powerful forward genetic methods (genome-independent) that have advanced model organism research for decades. In 2002 the genome sequence of Plasmodium falciparum, the parasite causing the most severe type of human malaria, was completed, eliminating many of the barriers to performing state-of-the-art molecular biological research on malaria parasites. Although new, licensed therapies may not yet have resulted from genome-dependent experiments, they have produced a wealth of new observations about the basic biology of malaria parasites, and it is likely that these will eventually lead to new therapeutic approaches. This review will focus on the basic research discoveries that have depended, in part, on the availability of the Plasmodium genome sequences.     

液晶纤维素及其衍生物材料的结构与性能

基于国内外最新研究文献，系统论述了液晶纤维素及其衍生物薄膜、纤维、功能分离膜、交联凝胶等材料的成型、结构与性能。指出这类液晶聚合物具有胆甾相或向列相液晶态。与各向同性态的同种材料相比，各向异性态的液晶纤维素及其衍生物材料具有更优异性能。双轴取向液晶三乙酸纤维素薄膜的拉伸强度和弹性模量分别可310MPa和6．3GPa；由液晶态干湿法纺丝所获得的高分子量纤维素纤维的抗张强度和弹性模量分别可高达2．2GPa和65GPa。液晶纤维素及其衍生物分离膜也表现出高得多的气体选择透过性能。其液晶交联凝胶中，凝胶所占质量分数高达98％，以及具有显著不同于各向同性态凝胶的液胀行为。液晶纤维素及其衍生物可望作为生产高级包装膜、功能纤维、气体分离膜、各向异性功能凝胶等的重要材料。     

Computational diffusion kinetics and its applications in study and design of rare metallic materials

Computational diffusion kinetics(CDK),with a spirit of and being coupled with the computational thermodynamics(CT,or called as the CALPHAD technique),plays increasingly important role in the alloy design/optimization and microstructure control during the processing of advanced metallic materials.This paper is to highlight recent progress of CDK in research with great focus on novel Ti and Zr alloys,which was largely performed in the authors’group.It ends with one representative example of the applications of CDK,coupled with CT,quantitative phase field,and three-dimensional(3D)statistical calculation,in designing the heattreatment schedule for the dual phase(αβ)Ti–6Al–4V alloys.     

Amorphous silica-like carbon dioxide

Among the group IV elements, only carbon forms stable double bonds with oxygen at ambient conditions. At variance with silica and germania, the non-molecular single-bonded crystalline form of carbon dioxide, phase V, only exists at high pressure. The amorphous forms of silica (a-SiO2) and germania (a-GeO2) are well known at ambient conditions; however, the amorphous, non-molecular form of CO2 has so far been described only as a result of first-principles simulations. Here we report the synthesis of an amorphous, silica-like form of carbon dioxide, a-CO2, which we call 'a-carbonia'. The compression of the molecular phase III of CO2 between 40 and 48 GPa at room temperature initiated the transformation to the non-molecular amorphous phase. Infrared spectra measured at temperatures up to 680 K show the progressive formation of C-O single bonds and the simultaneous disappearance of all molecular signatures. Furthermore, state-of-the-art Raman and synchrotron X-ray diffraction measurements on temperature-quenched samples confirm the amorphous character of the material. Comparison with vibrational and diffraction data for a-SiO2 and a-GeO2, as well as with the structure factor calculated for the a-CO2 sample obtained by first-principles molecular dynamics, shows that a-CO2 is structurally homologous to the other group IV dioxide glasses. We therefore conclude that the class of archetypal network-forming disordered systems, including a-SiO2, a-GeO2 and water, must be extended to include a-CO2.     

人类新基因克隆

本文概述了人类基因组计划及人类基因组研究的新进展,重点阐述了人类新基因克隆的策略与现状、问题与对策,同时就新基因克隆过程中的技术难点作了概括性的归纳,并就其突破分别提出可行的建设性意见,对从事这方面研究的科研人员具有重要的指导作用。     

吉林某煤炭资源枯竭型城市采矿区衍生地质灾害治理方法研究

煤炭资源型城市资源枯竭后,矿山开采衍生灾害长时间继续发生,同时还会形成新的灾害,会严重影响城市的经济发展和社会稳定,对这些灾害的治理是城市转型和可持续发展的基础。通过对具体工程实例中的治理方法进行总结和归纳,希望可以为其他资源枯竭型城市衍生灾害的治理提供启示。     

酿酒酵母基因组的研究进展

酿酒酵母(Saccharomyces cerevisiae)是第一个完成全基因组测序工作的真核生物,目前在结构基因组学、功能基因组学、模式生物、最小基因组、比较基因组学等方面的研究已经获得了重大的进展,为人类更深入地研究高等生物基因组打下了坚实的基础。本文将从这几个方面着手对酿酒酵母基因组的研究进展进行综述。     

Perspective on Materials Genome~

The author’s perspective on Materials Genome is presented in this paper through several related projects.Current thermodynamic and kinetic databases of multicomponent materials consist of Gibbs energy functions and atomic mobility of individual phases as functions of temperature,composition,and sometimes pressure,i.e.,with the individual phases based on crystal structures as the genome(building blocks)of materials.It is articulated that if an individual phase has its internal configurations,such as magnetic spin configurations and ferroelectric polarization,change significantly with respect to temperature,stress,and magnetic and electric fields,then those individual configurations instead should be considered as the genome of the individual phase.The‘‘mutation’’of an individual phase is governed by the entropy of mixing among the individual stable and metastable configurations,named as microstate configurational entropy,and responsible to anomalies in individual phases.Our ability to tailor the properties of those individual configurations as a function of compositions is the key for the design of materials.     

三明市高校高级知识分子体育锻炼参与状况的研究

采用问卷调查法、文献资料法和数理统计法,对三明市高校高级知识分子体育锻炼参与状况进行研究。研究结果表明:有58.8%的高级知识分子每周未能参加1次以上的体育锻炼,"工作忙无时间"是高级知识分子不参加体育锻炼的首要原因。高级知识分子采用的健身项目主要是以"长走"、"球类"、"健身操"、"跑步"为主;参加体育锻炼的场所主要是在体育场馆、公路或街道和公园";增强体质"是高级知识分子参加体育锻炼的首要目的。