Preparation and Application of Nanostructured Perovskite Phases

Transition metal oxide compounds with perovskite‐type structure (AMX_3‐δ) show besides attractive physical properties, such as high temperature superconduction or thermoelectricity, often excellent catalytic properties for various redox reactions. The catalytic reactivity is strongly dependent on composition, structure and of course the specific surface area of the compounds. Fine‐tuning of the properties can therefore be achieved by suitable cation‐ and anion‐ substitutions and by adjusting the morphology of the compounds. For systematic studies on the relationship between composition, structure and properties in these systems fine particles as well as thin films of identical compositions e.g. La_1‐xCa_xMO_3‐δ (x = 0, 0.3, 0.4 , 0.5) (M = Fe, Co, Ni, Mn, Ti) are produced with diverse “chimie douce” methods. The samples are characterised concerning their chemical and physical properties. Carbon nanotube composite materials have been produced by catalytic decomposition of gaseous carbon compounds on nanometer‐size transition metal clusters on top of perovskite‐type metal oxides and tested for a possible application as oxygen electrodes in air based batteries.     

Half-Metallic Ferromagnetism in New Half-Heusler Compounds: an Ab Initio Study of CrTiX (X = Si,Ge, Sn,Pb)

In this work, half-metallic (HM) properties of new Half-Heusler (HH) ferromagnetic compounds CrTiX (X = Si, Ge, Sn, Pb) are studied by means of first principle band structure calculation within the framework of density functional theory (DFT). From the spin-polarized calculations using full-potential linearized augmented plane-wave (FP-LAPW)method, we found that all of these compounds are stable in ferromagnetic MgAgAs-type crystal structure. The latticeparameters of CrTiX compounds increase with increasing atomic radius of X atom and ranges from 5.76 to 6.38 Å. The calculated electronic structure of these compounds in MgAgAs-type structure shows that they are HM materials with an integer magnetic moment of 4 μ _B. Densities of states, electronic band structure, and origin of ferromagnetism have been discussed, and robust HM nature of these compounds is analyzed which makes them fascinating compounds for spintronic devices.     

The influence of chemical structure and combustion reactions on the maximum experimental safe gap of industrial gases and liquids

The paper shows how the molecular structure of a compound and the nature of the intermediates formed during its combustion can influence the Maximum Experimental Safe Gaps (MESGs). A qualitative discussion estimates the MESG of compounds for which measurements are not available by comparing their molecular structure and combustion products with those of compounds having measured MESGs. A list of compounds is given with measured MESGs corrected to standard temperature and pressure. The MESGs of compounds in various species groups are positioned on figures to show how molecular structure affects the MESG.     

Structural and Magnetic Properties of MnFe$_1 - rm x$Co$_rm x$Ge Compounds

The structural and magnetic properties of MnFe_1-xCo_xGe compounds with x=0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.85,0.9, and 1.0 were investigated by means of X-ray diffraction (XRD) and magnetization measurements. XRD shows that the MnFe_1-xCo_xGe compounds crystallize in the hexagonal Ni₂In-type crystal structure for xles0.8 and in the orthorhombic NiTiSi-type structure for x>0.8. The magnetization measurements show that the MnFe_1-xCo_xGe compounds exhibit a complex magnetic behavior. The Curie temperature increases with increasing of x. The saturation magnetization of the compounds with Ni₂In type structure increase with increasing of x and the saturation of the magnetization in the NiTiSi-type structure also increases with increasing x. We investigated the magnetocaloric effects in these compounds by means of magnetization measurements. The maximum magnetic-entropy change observed in these compounds reaches 9 J/kgK for x=0.8 in a field change from 0 to 5 T at around 289 K     

高等院校工业工程专业本科培养计划国内外比较研究

在对国内外大学具有影响的工业工程专业本科培养计划调查的基础上,对各学校工业工程本科教育的专业计划、课程体系及教学内容进行了分析比较,并归纳总结了国内外大学在培养目标、课程设置、课程比例以及课程时数方面的异同。基于上述分析和比较,对我国高等院校工业工程专业本科教育的培养目标和课程体系设计提出了建议。     

Effects of particle size and structure of carbon blacks on the abrasion of filled elastomer compounds

The effects of the particle size and structure of various carbon blacks on friction and abrasion behavior of filled natural rubber (NR), styrene–butadiene rubber (SBR) and polybutadiene (BR) compounds were investigated using a modified blade abrader. The effect of particle size and structure on abrasion resistance should be considered for the optimum design of desired wear properties. Characteristic parameters were introduced from the particle size and the structure of carbon blacks, with a linear relationship between the Young’s modulus and these characteristic parameters. The frictional coefficient depended not only on the particle size, but also on the structure of carbon black. The rates of abrasion were decreased with increasing surface area and developing structure of carbon blacks. Abrasion rates of the compounds were found to be proportional to a power n of the applied frictional work input. It was also observed that BR compounds caused much slower wear than NR and SBR compounds. The worn surfaces of the rubber compounds filled with carbon black having smaller particle size and a more developed structure showed narrower spaced ridges and better abrasion resistance. It means that smaller particle size and better structure development of carbon black resulted in improved abrasion resistance.     

硅氧烷化合物的合成与应用进展

基于硅氧键特点以及不同条件的化学反应是构建结构迥异、性能独特的新型有机/无机硅氧功能材料的重要方法,近年来,引起了学术界的普遍关注。新型硅氧功能材料兼具有机/无机化合物性质,以其良好的生物相容性、耐高低温性以及电绝缘性能被广泛应用于众多领域。本文综述了硅氧烷化合物设计、合成与应用的研究领域及发展现状,重点介绍线性结构(一维结构)、非线性结构(二维结构)、多面体低聚倍半硅氧烷化合物(三维结构)以及有机/无机杂化硅氧烷化合物的设计及合成方法,并通过研究可拉伸聚硅氧烷弹性体、硅氧烷化合物涂层、新型驱油用硅氧功能材料等多种方式以增进硅氧烷化合物在生物医学、航空航天、功能材料及三次采油方面的应用进展。     

The Theme Course: Connecting the Plant Trip to the Text Book

A plant trip provides subjects for team projects and lecture examples in a sophomore chemical engineering course, thus becoming a unifying “theme” for the course. The “theme” structure is intended to improve student mastery of course material by helping students relate different course topics to one another via real equipment and processes. Here, performance in a subsequent junior chemical engineering course by students from the “theme course” is compared with performance by students who took the sophomore course in a traditional lecture‐homework‐exam format. Theme course graduates claim better retention of concepts from the sophomore course, though their scores on exam questions testing their knowledge, comprehension, and application of these concepts did not differ significantly from that of students from the traditional course. Theme course graduates did earn higher grades in the junior course, due to better performance on exam questions requiring higher level skills such as analysis, synthesis, and evaluation. Students were enthusiastic about the course structure, and expressed excitement about learning from “real life.” Thus the “theme” structure results in early student success in the skills necessary for engineering design, and generates student enthusiasm for engineering.     

Utilizing a Combination of TGA and GC-MS to Estimate Health-Based Risks from Off-Gassed Volatile Compounds

Off-gassed compounds emitted from various materials can, in some instances, present health risks. In order to assess the potential health risks, off-gassed compounds must be identified, quantified, and evaluated relative to known health-based exposure guidance levels. We present a simple screening method for doing this that combines thermogravimetric analysis with thermal desorption–gas chromatography–mass spectrometry. The masses of particular volatile compounds are estimated over the course of a short-term, acute exposure. Assumptions (or measurements) of a room size can be used to convert these mass estimates to estimated concentrations, which can then be compared with readily available health-based exposure thresholds.     

Hydrolysis of Tc(CO) 6 + cation in aqueous solutions. Crystal and molecular structures of the identified products: Tc2(CO)10 and Tc3H3(CO)12

Hexacarbonyltechnetium(I) cation undergoes rapid hydrolysis in aqueous solutions at pH ≥ 7 with the formation of an unidentified carbonyl compound or mixture of compounds in the form of a pale yellow precipitate. Two crystalline fractions were isolated in the course of vacuum sublimation of the precipitate and were identified by single crystal X-ray diffraction as Tc₂(CO)₁₀ and Tc₃H₃(CO)₁₂. The crystal and molecular structures of these compounds were described. The mechanism of their formation in the course of hydrolysis of [Tc(CO)₆]⁺ cation is discussed.     

照相有机物结构鉴定

简述了有机化合物结构鉴定的常用程序。以照相有机物及其中间体为例，介绍了谱图综合解析在未知物结构鉴定中的应用。     

Mathematical modelling of hydration of cement: Hydration of dicalcium silicate

The hydration stoichiometry, products and kinetics of dicalcium silicate are summarized. Hydration takes a similar course to tricalcium silicate, but at a much slower rate. The differences and similarities between the two compounds are identified and discussed, and future research needs identified.     

Magnesium Potassium Phosphate Compound for Radioactive Waste Immobilization: Phase Composition,Structure, and Physicochemical and Hydrolytic Durability

Low-temperature mineral-like magnesium potassium phosphate (MPP) compounds were synthesized in the course of immobilization of nitric acid solutions containing cesium, strontium, sodium, ammonium, lanthanum, and iron as simulated radioactive waste (RW). The phase composition and structure of the compounds and the distribution of the RW components were studied. The mechanical strength (15 ± 3 MPa), heat resistance (up to 450°С), and radiation resistance (absorbed dose 1 MGy) of the compounds were evaluated in accordance with the existing regulations. The MPP compound exhibits high hydrolytic durability: The differential leach rate of ²³⁹Pu and ¹⁵²Eu on the 28th day, measured in accordance with GOST (State Standard) R 52 126–2003, is 2.1 × 10^–6 and 1.4 × 10^–4 g cm^–2 day^–1, respectively. Introduction of wollastonite into the compound decreases the radionuclide leach rate by a factor of up to 5. The MPP compound shows promise for industrial solidification of liquid RW, including high-level highly saline multicomponent actinidecontaining waste.     

NaZn13型LaFe基室温磁致冷材料研究进展

介绍了LaFe基室温磁制冷材料在制备和磁热效应方面的研究进展.具有NaZn13型结构的LaFe基化合物中含有高的Fe含量,是良好的软磁材料.LaFe基化合物的居里温度可以通过Co取代Fe或添加非金属元素H、C、B等来提高;应用甩带和其他稀土元素取代La可以缩短制备NaZn13的退火时间.通过调整LaFe基化合物的元素配比可能会制备出具有巨磁热效应的室温磁制冷材料.     

Defects in epitaxial films of semiconducting compounds with the sphalerite structure

The crystallography of point defects, dislocations, grain boundaries, misfit dislocation networks, and polytypes in semiconducting compounds with the sphalerite (zincblende) structure is outlined. The methods available for depositing films of compounds are reviewed with reference to the problem of non-stoichiometry. The variation of film structure with substrate temperature is considered, and the few published results of studies of the phase structures and the defect content of epitaxial films of semiconducting compounds are described. The experimental methods available for more detailed analysis of these features are then pointed out.     

Predicting lattice constant of complex cubic perovskites using computational intelligence

Recently in the field of materials science, advanced computational intelligence (CI) based approaches are gaining substantial importance for modeling the quantitative structure to properties relationship. In this study, we have used support vector regression, random forest, generalized regression neural network, and multiple linear regression based CI approaches to predict lattice constants (LCs) of complex cubic perovskites. We have collected reasonable number of perovskites compounds from the recent literature of materials science. The CI models are developed using 100 training compounds and the generalized performance is estimated for the novel 97 compounds. Our analysis highlights the improved prediction performance of CI approaches than the well-known SPuDS software, which is extensively used in crytsallography. We further observed that, for some of the compounds, the larger prediction error provided by the CI models is correlated with the structure deviation of the compounds from its ideal cubic symmetry.     

离子型层状化合物制备及应用研究

简单介绍离子型和非离子型两类层状化合物的结构和性能,重点概括了以 LDH为代表的阴离子型层状化合物和以α 磷酸盐为代表的阳离子型层状化合物的制备以及研究进展。     

Tb2Fe17-xCrx化合物的结构与磁性

通过X射线衍射及磁测量手段研究了Tb2Fe17-xCrx（x=0、0．5、1．0、1．5、2．0、3．0)化合物的结构与磁性。研究结果表明Tb2Fe17-xCrx化合物具有Th2Ni17型结构，随着Cr替代量x的增加，Tb2Fe17-xCrx化合物的单胞体积呈现非线性的减小，而晶胞参数a、c呈现复杂的变化。分析表明Tb2Fe17-xCrx化合物中存在着较强的磁一弹耦合效应。对磁性质的研究结果表明随着Cr替代量x的增加，Tb2Fe17-xCrx化合物的居里温度升高，在x=1．0时达到最大值，为539K，当Cr替代量x继续增加时，Tb2Fe17-xCrx化合物的居里温度下降。随着Cr替代量x的增加，Tb2Fe17-xCrx化合物的自发磁化强度急剧下降，分析表明在Tb2Fe17-xCrx化合物中，Cr的磁矩反平行于Fe的磁矩。     

卓越课程“包装结构设计”的改革实践

依据《江南大学卓越课程建设管理办法》,卓越课程须对课内外教学内容与时数进行统筹安排,实践教学方法及其考核方式须进行改革。包装结构设计课程的实践性和应用性较强,在卓越课程改革中,将包装结构设计课程实践性教学环节设置为"实践(课堂讨论+课程项目调研+实验课+创意设计教学=设计实践与作品)+物化成果"模式;课程考核包含了平时课堂讨论情况、设计实践与作品、卷面成绩几个部分,物化成果已成为学生考核成绩的重要参考项目。实践性教学的加强与具有创新激励作用的公平评价方案,极大地提升了学生的学习热情,其学习的主动性及其综合能力均得到了较大提高,同时包装结构设计课程教学的物化成果也有了较大幅度的增加。     

包装CAD教学点滴

文中分析了包装CAD课程的结构，提出课程的设置，课程与包装工程专业的关系，从而要求学好包装CAD。