珍珠粉与三角帆蚌贝壳粉的物质组份区分

本文采用红外光谱法、热分析法、氨基酸分析法检测了珍珠粉、三角帆蚌贝壳粉的物质组份,证实了两者无机组份基本一一致,有机组份中存在一定差异,从而得出了鉴定方法。     

S—Se系统玻璃半导体的制备及其性质(研究阶段进展报告)

叙述了S—Se系统玻璃半导体的组份、析晶及其性质。由玻璃的组份、析晶及分疑相的关系,确定了生成均质玻璃组份范围。研究揭示了玻璃组份与可见光谱特性和电导率的关系。测定了均质玻璃膜的光致光学性质,证明它是一种位相型光全息存储材料。     

单组份聚氨脂漆的研制

自干单组份聚氨酯漆是一种新产品,它的物化性能与双组份聚氨酯漆基本一致,而施工性能等优于双组份。     

用等压进样法分析纯氩中微量氢,氧,氮,甲烷

用气相色谱法热导检测器分析纯氩中微量氢、氧、氮、甲烷组份时,采用等压进样技术,消除了进样压力峰的干扰,从根本上改善了氢组份无法检测的状况。由于对色谱条件没有干扰,可以使色谱条件选择在最佳状态,检测灵敏度大大提高,一次进样就可得到4种组份的分析结果。本方法很适合氩气的生产控制分析和产品检验。同样,等压进样技术也可用于其它气体的微量组份分析中。     

特纯物质展览会展品杂质组份

特纯物质展览会展品杂质组份等永久气体本文继续报道特约物质展览会上挥发性物质样品的杂质组份数据’‘－‘ｊ。本文主要介绍永久气体特纯样品杂质组份的情况。永久气体和二氧化碳在特纯物质展览会上共有８种物质１７个样品（表１）。Ｍ氧化碳、氮、氦、氖、氖、氨各有２...     

聚氨酯密封腻子

聚氨酯密封材料具有高的强度、高的耐磨性、良好的弹性和耐老化性。因此在密封腻生产中聚氨酯弹性体的需求量不断增加。一、双组份聚氨酯密封腻子以多官能团含异氰酸根组份为基础的     

新时期木材检验工作重要性的几点思考

木材检验工作是合理利用木材资源、控制木材生产质量、企业进行经济考核、贯彻执行木材标准、提高企业经济效益的重要保证,是兼顾国家、企业和个人利益的重要环节,因此新时期强化木材检验工作刻不容缓。面对激烈的市场竞争和日益稀缺的木材资源,企业必须规范木材检验工作、木材检验人员必须提高技术水平、国家相关部门必须完善木材检验标准,从而真正发挥木材检验工作是应有功效。     

煤沥青——炭素制品优良的粘结剂

本文对煤沥青的构成、溶提研究方法的发展和现状作了较系统的介绍与评论。对于沥青的一些工艺性质如粘性性质等与溶提组份的关系做了论述。对于有争议的Q1组份的性质作了较深入的讨论。文章还试图在现有资料的基础上对各组份作出尽可能清晰的描述,并在沥青的工艺性质与各组份之间建立联系。文章还对沥青作为炭素材料粘结剂应开展的研究工作的方向提出了看法。     

导电硅橡胶基体粘度及组分对导电性能的影响

硅橡胶基体黏度及组分的不同,对导电橡胶填料的分散性、体系压阻特性及稳定性影响不同。通过将单组份室温硫化硅橡胶GD401、不同黏度的双组份室温硫化硅橡胶107以及双组份室温硫化硅橡胶GMX-331D与乙炔炭黑反应制备了导电硅橡胶。研究了导电硅橡胶的渗滤阀值、压阻特性及压阻范围。讨论了导电硅橡胶的迟滞及弛豫性能。研究表明,导电硅橡胶的渗滤阀值为6%炭黑填充质量分数,渗滤区间为6%~10%之间;基体硅橡胶的粘度越高,压阻特性越好,电阻弛豫时间越短,电阻迟滞性系数越小;双组份基体比单组份基体压阻特性曲线的光滑度好,电阻弛豫时间短,电阻迟滞性系数小。     

特纯物质展览会展品杂质组份 10．一般固态物质、永久气体、挥发性氯化物、氢化物和金属有机化合物的纯度等级

根据对自１９７４年起列入常设特纯物质展览会的高纯物质展品中杂质组份的研究结果．介绍了一般固态物质、永久性气体、挥发性氯化物、氢化物和金属有机化合物杂质组份的特性和纯度等级．     

Nature’s hierarchical materials

Many biological tissues, such as wood and bone, are fiber composites with a hierarchical structure. Their exceptional mechanical properties are believed to be due to a functional adaptation of the structure at all levels of hierarchy. This article reviews the basic principles involved in designing hierarchical biological materials, such as cellular and composite architectures, adapative growth and as well as remodeling. Some examples that are found to utilize these strategies include wood, bone, tendon, and glass sponges – all of which are discussed.     

The radial reinforcement of the wood structure and its implication on mechanical and fracture mechanical properties—A comparison between two tree species

The radial direction of wood is reinforced by an additional tissue called rays. These rays are one of the reasons for the anisotropy of wood in the transverse plane. In this paper the influence of rays on the mechanical properties like tensile strength as well as on fracture mechanical parameters like critical stress intensity factor and specific fracture energy is shown. By investigating two deciduous tree species with a similar wood structure in general but a different ray characteristic in particular the importance of this radial reinforcement of the wood structure could be demonstrated. The relevance for the living tree is discussed.     

利用木材介孔结构制备新型复合材料研究进展

综述了近年来关于木材多孔结构的新概念以及利用木材多孔结构制备新型复合材料和功能材料的新方法、新技术．重点介绍了陶瓷化木材、金属化木材的制备和应用以及以木材为多孔模板的新材料的合成。利用木材独特的多孔结构和介孔结构，设计、制备结构和功能独特的新材料是仿生材料科学和介孔材料科学一个非常值得关注的研究领域。     

Experimental testing of wood‐concrete and steel‐concrete composite elements in comparison with numerical testing

The paper presents the results of experimental tests with a numerical comparison of some typical composite element systems. Two different kinds of elements were tested: composite steel‐concrete and composite wood‐concrete elements. Deflections at midspan under monotonously increasing static load on simply supported beams were measured. The affects of different types of composite connections on the results were researched. In numerical tests the structure was modeled with two‐dimensional plane elements. The composite surface was modeled with two‐dimensional contact (interface) elements for the continuous connection simulation and modified beam elements for the discrete connection simulation. The applied material models include the most important nonlinear effects of concrete, steel and wood behavior, as well as the nonlinear behavior of the composite surface at the connection. The achieved results of the developed numerical model were compared with the results obtained through the experimental test.     

Multiscale mechanical and structural characterizations of Palmetto wood for bio-inspired hierarchically structured polymer composites

There has been a great deal of effort focused on engineering polymer composites with hierarchical microstructures consisting of one or more ingredients that can be organized differently across multiple length scales. However, there are hierarchical microstructures that have evolved over eons in biological materials. These unique structure–property relationships may serve as templates for engineering hierarchically structured polymer composites with tailored properties. One such biological material is the Palmetto wood of South Carolina, which was successfully used as a protective structure during the Revolutionary and Civil Wars to absorb cannon shot. Through an assembly of microfibers into macrofibers embedded in a cellulose matrix, the Palmetto wood has optimized its ability to resist failure when subjected to extreme dynamic loading events, such as hurricanes. Understanding of the dynamic and static structure–property relationship in Palmetto wood can facilitate the development of new hierarchically structured polymer composites with increased resistance to failure. Therefore, the structure–property relationship in Palmetto wood has been studied using novel multiscale microstructural and mechanical characterization techniques. Models have been developed that indicate that the hierarchical structure of Palmetto wood obeys the linear Rule-of-Mixtures across multiple length scales. This understanding has led to the development of new polymer composite structures that exhibit properties similar to Palmetto wood using conventional laminated carbon fiber–epoxy composites and new polymer nanocomposites consisting of carbon nanofibers. The use of the nanofibers appears to enhance the interaction between the composite components in a manner similar to the interaction between fibers in the Palmetto wood that enables the laminated composite to behave more like the individual layers by resisting the tendency to delaminate and increasing the Weibull statistical parameters closer to those observed in Palmetto wood.     

Deformation mechanisms in cellulose fibres, paper and wood

The use of Raman spectroscopy in probing the deformation mechanisms of cellulose fibres (regenerated and natural), and two natural cellulose composite systems (wood and paper) is described. It is shown that during tensile deformation the 1095 cm^–1 Raman band, corresponding to the stretching of the cellulose ring structure, shifts towards a lower wavenumber due to molecular deformation. By analysing a number of fibres with different microstructures this shift is shown to be invaluable in understanding the micromechanisms of deformation in these materials. Moreover, the rate of Raman band shift is shown to be invariant with stress for all fibre types, consistent with a fibre microstructure based on a modified series aggregate model. In the composite systems, such as wood and paper, it is shown that the stress-induced Raman band shift in the cellulose gives an important insight into their local deformation micromechanics.     

Relationship between wood elastic strain under bending and cellulose crystal strain

Wood is a natural composite material with a complex multi-scale structure. Its stiffness is mainly due to crystalline cellulose fibrils reinforcing the cell walls. In order to quantify the contribution of cellulose to wood elastic properties in both tension and compression, the change in cellulose (0 0 4) lattice spacing (cellulose crystal strain) was measured by X-ray diffraction during a bending test on poplar specimens. A detailed methodology is presented to accurately quantify this cellulose crystal strain. Results show that during elastic loading, cellulose crystal strain is roughly proportional to wood strain. The strain ratio (cellulose crystal strain/wood strain) was close to 0.75, and did not differ significantly in tension and compression. Interpretation of the strain ratio with respect to cellulose orientation shows that part of the wood strain occurs without inducing cellulose crystal strain. This contribution amounts to 10–15% of wood strain, and its possible origin at different levels of wood ultra-structure is discussed.     

A new hybrid concept for sandwich structures

Sandwich structures are considered as optimal designs for carrying bending loads and can be either metal (aluminium faces and honeycomb or metal foam cores) or polymer structures (composite faces with polymer foam cores). In this paper, a new hybrid sandwich structure has been developed by combining most of the advantages of metallic and polymeric materials while avoiding some of their main disadvantages. For this new concept metal sheets are used at the outer surfaces to maximize rigidity while introducing in between lightweight cores adhesively bonded to keep the whole structure together. Furthermore, composite or wood layers may be used as intermediate layers to improve impact resistance. Potential methods for the manufacturing of this new structure are based on compression under vacuum. The results include the study of several panel configurations theoretically based on Finite element analysis and on the modified simplified equations and experimental results in the most representative cases of the study.     

木/塑复合材料及其增强机理的研究

本文概述了木/塑复合材料的主要配方、工艺和材料的主要力学性能、物理特性及其与其他材料性能比较;观察和分析木/塑复合材料的微观结构形态研究其增强机理;简要提出木/塑复合材料的应用范围。     

仿生制备多孔ZrC/C复合陶瓷材料

以碳化后的梧桐木块作为碳模板,采用金属锆作为锆源,在KCl和KF的混合熔盐体系中制备了多孔ZrC/C复合陶瓷材料。研究了不同碳化温度对碳模板的显微形貌、显气孔率和体积密度的影响。并采用X射线光电子能谱(XPS)、傅里叶变换红外光谱(FTIR)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征了梧桐木的碳化过程以及复合材料的物相组成和显微形貌。结果表明:梧桐木的碳化分为有机物的热分解和石墨化两个过程;碳化后的梧桐木保留了多孔的特征结构,随着碳化温度的升高,碳模板显气孔率变大,体积密度减小;反应时间的延长有利于增强ZrC层与碳模板基体表面的结合力;KF的加入量需要严格控制,过量的KF会破坏复合材料的结构。