离子辐照引起的金属／绝缘体界面混合与相变研究

载能离子穿过固体界面引起界面原子迁移使界面原子混合和物质成分变化，从而导致界面发生材料相变。简要介绍了载能离子辐照引起金属／绝缘体界面混合效应及相变现象的主要实验研究进展、低能离子和高能离子辐照引起金属／绝缘体界面现象差异，并对离子辐照引起界面混合及相变的机制进行了初步探讨。When penetrating an interface between two kind of solids, energetic ions can induce atomic diffusion at both sides of the interface and then result in intermixing, atom re-distribution or composition change, as well as phase transformation. Main progress on the study of intermixing and phase change at metal/insulator interface induced by energetic ion irradiations, the difference of phenomena occurred at metal/insulator interfaces induced by high-and low-energy ions were briefly reviewed. Furthermore, the possible mechanisms related to intermixing and phase change at metal/insulator interface produced by energetic ion irradiations were also discussed in short words.     

An existence result for a two‐phase Stefan problem arising in metal casting

We present a model arising from the thermal modelling of two metal casting processes. We consider an enthalpy formulation for this two‐phase Stefan problem in a time varying three‐dimensional domain and consider convective heat transfer in the liquid phase. Then, we introduce a weak formulation in a fixed domain, by means of a suitable transformation. Existence of solution is obtained by applying an abstract theorem. The proof of this theorem is done by taking an implicit discretization in time together with a regularization. By passing to the limit in the regularization parameter and in the time step, we obtain the existence of solution of the continuous problem. Copyright © 2005 John Wiley & Sons, Ltd.     

高功率型镍氢电池的循环性能

由于没有镉污染,对环境友好,用于高功率设备的镍氢电池的需求量增长很快,目前每年的需求量约为5亿只.但是镍氢电池的一些性能还不能完全满足电动工具的使用要求,突出表现在电池大电流充放循环寿命较差.因此,研制高性能的高倍率镍氢电池不仅具有重要的研究意义,也有很大的应用价值.本文研究影响SC型动力电池循环寿命衰减的主要因素,测量了在大电流循环过程中镍氢电池的内阻、温度及重量变化,并运用SEM、XRD对电池内阻升高的原因进行了分析.我们认为电池内阻升高是镍氢电池大电流循环寿命差的主要原因,分析发现在镍氢电池进行大电流充放电循环时,电池正极膨胀,负极微粉化,电池内部孔隙率增加,致使电解液干涸,电池内阻升高.通过增加负极容量,抑制正极膨胀,可以有效改进镍氢电池大电流充放时的循环性能.     

双面金属包覆介质波导模序数的判别方法

在双面金属包覆介质波导中 ,随着介质层厚度的变化 ,会出现TM0 模与TM1 模的分离和简并两种状态 ,从而影响衰减全反射 (ATR)谱中模序数的确认。通过对金属波导的理论分析和实验研究 ,提出了三种模序数确认方法 :本征角计算法、吸收峰全峰半宽比较法和吸收峰峰间距比较法 ,实现了两种状态下对模序数的准确判断     

双金属氧化物和氧化物载体组分间的相互作用

讨论了一些过渡金属氧化物（NiO,CuO或MoO3)在经改性所得复合载体（TiO2-γ-Al2O3，MoO3-t-ZrO2或NiO-t-ZrO2)上的分散作用，这些三地体系中实验测定的氧化物分散容量与研究负载型二元氧化物体系所得嵌入模型的估算值基本相符；样品的表面组成、结构和性能与载体的表面结构、过渡金属氧化物的负载量和加料顺序以及焙烧温度密切相关。     

Laser vaporization: A versatile method for studying metal clusters

Vaporizing solid samples of metals and semiconductors with a YAG Laser is a method well suited for producing molecules and clusters of those materials. The clusters are examined by either laser-induced fluorescence (LIF) or mass spectroscopic methods. The technique is valuable for both gas phase and matrix studies. The method is described and some applications, studying either the structure of small metal molecules or their reactions, are reviewed, with emphasis on our recent results from the LIF studies of LiBe, Al₂ and the reaction of Al with oxygen, yielding A1₂O. For larger clusters, Ion Cyclotron Resonance is an extremely valuable method, as we demonstrate by its application to the reactions of small charged silicon clusters with strong oxidising agents.     

Photo-Absorption and photochemical decomposition of copper and alkaline-earth ß-diketonates as source gases of high-Tc superconducting films

For low-temperature deposition of oxide films relating to Bi-Sr-Ca-Cu-O superconductors, photo-absorption and -decomposition properties were examined with respect to copper and alkaline-earth ß-diketonates. It was confirmed that all ß-diketonates examined were promising as source materials for photochemical vapour deposition (photo-CVD) using a low-pressure mercury lamp, in view of their large light absorption coefficients at wavelength 254 nm. The light irradiation was effective for the formation of highly crystalline oxide films at temperatures below 600 °C. By combining two sources, Ca₂CuO₃ and SrCuO₂ films were prepared. Photo-CVD of c-axis oriented Bi₂Sr₂CuO_x film was achieved by the irradiation of ternary sources of Bi(C₆H₅)₃ and strontium and copper ß-diketonates at 500 °C.     

The transition of spontaneous polymerization of acrylamide to “explosive” regime

Experimental results related to the transition of spontaneous polymerization of acrylamide complexes with metal nitrates to the “explosive” regime at room temperature are presented. It is suggested that the “explosion” has a thermal nature. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 859–861, April, 1997.     

负载型金属氧化物常温精脱硫剂的制备与表征

以γ—Al2O3为载体，用浸渍沉淀法制备复合金属氧化物脱硫剂，添加竞争吸附剂得到高分散、均匀型金属氧化物精脱硫剂。常温、缺氧条件下精脱H2S穿透硫容可达16．8％．采用EP、TEM技术分析了金属氧化物活性组分的均匀分布及脱硫前后的脱硫剂微表面的变化。