梯度结构聚晶金刚石复合片组分优化设计

利用有限元方法对梯度结构聚晶金刚石复合片在制造过程中产生的残余热应力进行了计算,并分析了梯度组成分布指数及梯度层层数对热应力的影响。优化结果表明,分布指数最佳值为1.2,功能梯度层数为6层;与普通双层结构聚晶金刚石复合片相比,轴向拉应力由986 MPa降到了323 MPa,剪应力由722 MPa降到454 MPa;此外还改善了界面处的应力分布,大大提高了界面的结合强度。     

Magnesium Isotopic Compositions of International Geological Reference Materials

Magnesium isotopic compositions are reported for twenty‐four international geological reference materials including igneous, metamorphic and sedimentary rocks, as well as phlogopite and serpentine minerals. The long‐term reproducibility of Mg isotopic determination, based on 4‐year analyses of olivine and seawater samples, was ≤ 0.07‰ (2s) for δ²⁶Mg and ≤ 0.05‰ (2s) for δ²⁵Mg. Accuracy was tested by analysis of synthetic reference materials down to the quoted long‐term reproducibility. This comprehensive dataset, plus seawater data produced in the same laboratory, serves as a reference for quality assurance and inter‐laboratory comparison of high‐precision Mg isotopic data.     

Determination of Rare Earth Elements, Y, Th, Zr, Hf, Nb and Ta in Geological Reference Materials G-2, G-3, SCo-1 and WGB-1 by Sodium Peroxide Sintering and Inductively Coupled Plasma-Mass Spectrometry

Data are reported for rare earth elements (REE), Y, Th, Zr, Hf, Nb and Ta in four geological reference materials using sodium peroxide (Na₂O₂) sintering and inductively coupled plasma-mass spectrometry. The described procedure was used by students during their thesis work. A compilation of their reference material data acquired over one year of laboratory work demonstrates the ease and reliability of the method and the high reproducibility of the analytical results. Relative standard deviations of up to thirty six measurements of one reference material were lower than 5% for Y and the REE. Reproduciblities of Zr, Hf, Nb, Ta and Th were higher at between 5% and 10%, and can be attributed to the inhomogeneous distribution of zircon and other trace mineral phases and uncorrected drift effects. The concentration data are compared to reference and literature values and demonstrate that the procedure is also accurate. New data on G-3 show some systematic deviations from G-2, which are statistically significant.     

锗矿石和铟矿石化学成分分析标准物质研制

目前国内外没有以稀散元素锗、铟为特征元素的矿石标准物质,为了满足我国地质找矿的需求,本文采集广东省韶关凡口铅锌矿作为锗矿石候选物,广西南丹铜坑铅锌矿作为铟矿石候选物,依据国家一级标准物质技术规范,由10家实验室采用化学分析方法和现代仪器分析方法协作定值,研制了1种锗矿石标准物质(GBW07831)和1种铟矿石标准物质(GBW07833)。锗矿石标准物质定值组分为45项,铟矿石标准物质定值组分为47项,包括特征元素、共存元素、稀土元素(15项)、造岩元素和痕量元素,其中锗矿石中锗含量为21.6×10-6,铟矿石中铟含量为39.7×10-6。研制的2种标准物质丰富了我国矿石标准物质的种类,可用于锗、铟矿石化学成分分析测试的量值标准和日常质量监控。     

Molybdenum Concentrations Measured in Eleven USGS Geochemical Reference Materials by Isotope Dilution Thermal Ionisation Mass Spectrometry

Molybdenum concentrations in eleven USGS geochemical reference materials AGV-1, BCR-1, BHVO-1, BIR-1, DNC-1, DTS-1, G-2, GSP-1, MAG-1, PCC-1 and W-2 were measured by isotope dilution thermal ionisation mass spectrometry (ID-TIMS). In every case but one, the concentrations determined in this study were significantly lower than the current consensus values. Molybdenum concentrations determined by ID-TIMS are inherently more accurate and precisions may be up to an order of magnitude higher than those measured by other analytical techniques.     

A constitutive model for the dynamic and high‐pressure behaviour of a propellant‐like material: Part I: Experimental background and general structure of the model

This paper is the first part of a work that aims at developing a mechanical model for the behaviour of propellant‐like materials under high confining pressure and strain rate. The behaviour of a typical material is investigated experimentally. Several microstructural deformation processes are identified and correlated with loading conditions. The resulting behaviour is complex, non‐linear, and characterized by multiple couplings. The general structure of a relevant model is sought using a thermodynamic framework. A viscoelastic‐viscoplastic‐compaction model structure is derived under suitable simplifying assumptions, in the framework of finite, though moderate, strains. Model development, identification and numerical applications are given in the companion paper. Copyright © 2001 John Wiley & Sons, Ltd.     

Book Reviews

Books reviewed: D. Graham Burnett, Masters of All They Surveyed: Exploration, Geography, and a British El Dorado Garrett A. Sullivan, Jr., The Drama of Landscape: Land Property and Social Relations on the Early Modern Stage Sergio Díaz‐Briquets and Jorge Pérez‐López, Conquering Nature: The Environmental Legacy of Socialism in Cuba Karl F. Nordstrom, Beaches and Dunes of Developed Coasts Robin W. Doughty, The Eucalyptus: A Natural and Commercial History of the Gum Tree James K. Mitchell, ed., Crucibles of Hazard Gerald T. Koeppel, Water for Gotham: A History Arnold R. Alanen and Robert Z. Melnick, eds., Preserving Cultural Landscapes in America Kavita Pandit and Suzanne Davies Withers, eds., Migration and Restructuring in the United States Steven R. Nivin, Regional Innovation Potential: The Case of the U.S. Machine Tool Industry Douglas Meyer, Making the Heartland Quilt: A Geographical History of Settlement and Migration in Early Nineteenth‐Century Illinois David R. Meyer, Hong Kong as a Global Metropolis Mark Cleary and Goh Kim Chuan, Environment and Development in the Straits of Malacca David Zurick and P. P. Karan, Himalaya: Life on the Edge of the World Christer Jönsson, Sven Tägil, and Gunnar Törnqvist , Organizing European Space Tor Bernhardsen, Geographic Information Systems: An Introduction, 2nd ed.     

Predicting the overall properties of composite materials with small-scale inclusions or cracks

This paper will summarise the present state of knowledge concerning the elastic and dissipative properties of composite materials in the long wavelength or static approximation. In this case the material, although containing numerous inclusions or cracks or other types of microstructure, can be regarded as a continuum. Established results are listed for the elastic parameters following a review of approximate and exact methods of their derivation.     

介孔分子筛材料合成及应用研究的现状及进展

介孔分子筛材料是近年来引起人们广泛关注的一类新型功能材料，由于其具有孔分布有序且孔径均匀等结构优点而在催化、电磁传感器、纳米光学器件和色谱载体等领域中有潜在的应用价值。本文全面综述了介孔材料材质及机理的研究概况，合成方法，模板剂、助剂对于介孔分子筛材料合成的影响，以及介孔材料的应用研究，并就该类材料在合成和应用领域中存在的问题及研究方向做了简要论述。     

医疗材料的研究进展

对近年来包括本校海洋药物与食品研究所在内的研究机构在医疗材料上的研究提出综述报导。内容分4部分:高分子材料,生物材料,高分子材料和生物材料的复合物以及中草药。