Synthesis and Crystal Structure of RE[CH_2(CH_2)_4CONC_4H_9]_3(NO_3)_3(RE=Dy,La)

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆＲＥ［ＣＨ２（ＣＨ２）４ＣＯＮＣ４Ｈ９］３（ＮＯ３）３（ＲＥ＝Ｄｙ，Ｌａ）ＷａｎｇＨａｎｚｈａｎｇ（王汉章），ＸｕＱｉｎｇｆｅｎｇ（徐庆锋），ＱｉａｎＰｕ（钱朴）ＳｕｎＪｉａｎｐｉｎｇ（孙建...     

宣钢近北庄铁矿露采边坡稳定的结构分析

以宣钢近北庄铁矿露采边坡稳定性研究为例，说细说明了岩体结构分析方法的应用。     

双室工频感应炉的研制

介绍了双室工频感应炉的工作原理,炉子主要结构及其技术特征。     

Structure and formation energy of steps on the GaAs(001)-2 × 4 surface

The energies of various steps on the As-terminated GaAs(001)-2 × 4 surface are evaluated using a novel, approximate method of “linear combination of structural motifs”. It is based on the observation that previous total energy minimizations of semiconductor surfaces produced invariably equilibrium structures made of the same recurring local structural motifs, e.g. tetrahedral fourfold Ga, pyramidal threefold As, etc. Furthermore, such surface structures were found to obey consistently the octet rules as applied to the local motifs. We thus express the total energy of a given semiconductor surface as a sum of (i) the energies _M of the local structural motifs appearing in the surface under consideration and (ii) an electrostatic term representing the Madelung energy of point charges resulting from application of the octet rule. The motif energies are derived from a set of pseudopotential total energy calculations for flat GaAs(001) surfaces and for point defects in bulk GaAs. This set of parameters suffices to reproduce the energies of other (001) surfaces, calculated using the same pseudopotential total energy approach. Application to GaAs(001)-2 × 4 surfaces with steps reveals the following. (i) “Primitive steps”, defined solely according to their geometries (i.e. step heights, widths and orientations) are often unstable. (ii) Additional, non-geometric factors beyond step geometries such as addition of surface adatoms, creation of vacancies and atomic rebonding at step edges are important to lower step energies. So is step-step interaction. (iii) The formation of steps is generally endothermic. (iv) The formation of steps with edges parallel to the direction of surface As dimers (A steps) is energetically favored over the formation of steps whose edges are perpendicular to the As dimers (B steps).     

双辊铸轧机生产工艺对组织和性能的影响

就用双辊铸轧机(TRC)生产薄、宽铸轧带技术进行研究并优化铸轧工艺。研究结果表明：3mm厚的铸轧带不仅表面变形．而且整个厚度内部层都发生变形，表面层的铝基中具有较高的合金元素饱和度。     

湘潭新大粉末冶金设备制造有限公司的一体化真空烧结炉

简要介绍了湘潭新大粉末冶金设备制造有限公司研制的一体化真空烧结炉的炉子结构、脱蜡系统、工艺气体的引入系统、设备的控制系统以及炉子性能的鉴定结果。     

New chemical structural features of coal. The structure of coal products

The object of this paper is to demonstrate the usefulness of the transalkylation reaction for determining chemical structural features of products derived from coal. For example, the method is applied to derivatized coals, coals modified by thermolysis, and materials physically or chemically separated from coals. Data are presented for the pyridine soluble and insoluble parts of two coals, an O-methylated coal, a Birch reduced coal, a solvent refined coal, and a coke. Similarities and differences in chemical make-up of these materials are discussed.     

Evaluation of the reactivity of titanium with mould materials during casting

A methodology for evaluating the reactivity of titanium with mould materials during casting has been developed. Microhardness profiles and analysis of oxygen contamination have provided an index for evaluation of the reactivity of titanium. Microhardness profile delineates two distinct regions, one of which is characterised by a low value of hardness which is invariant with distance. The reaction products are uniformly distributed in the metal in this region. The second is characterised by a sharp decrease in microhardness with distance from the metal-mould interface. It represents a diffusion zone for solutes that dissolve into titanium from the mould. The qualitative profiles for contaminants determined by scanning electron probe microanalyser and secondary ion mass spectroscopy in the as-cast titanium were found to be similar to that of microhardness, implying that microhardness can be considered as an index of the contamination resulting from metal-mould reaction.     

Deposition mechanisms in langmuir-blodgett films

As part of a study of the possible application of polymerisable Langmuir-Blodgett (LB) films as ultra-fine-line e-beam resists, an investigation of the variation of film structure of 22-tricosenoic acid with differing deposition conditions has been made. Unexpected effects with significant implications for deposition speed and resist sensitivity have been observed, and the new techniques for film characterisation developed during the investigation have resulted in a revised model of deposition explaining the observed independence of the disorder causing optical scattering and the macroscopic features observed by polarised microscopy.     

热流体喷射变形机理与喷嘴结构

高速短程纺技术能生产三维卷曲短纤维,该技术的关键之一是热流体喷射装置。本文介绍了热流体喷射装置的演变与特点及它的加工机理和某些已应用的实际装置。