Formation of Amorphous AgI Aggregates Dominating Fast Ion Conductivity in AgI-based Glasses

Precise calorimetry was performed for (AgI)_x(AgPO₃)_1–x and (AgI)_x(Ag₂PO_3.5)_1–x glasses with very high AgI compositions (x0.75). The glasses showed -glass transitions due to the freezing-in of the rearrangement of conductive Ag⁺ ions. Magnitude of the associated heat-capacity jump increased with increasing the AgI composition in the respective glass systems, and was larger in the former system than in the latter when compared at the same AgI composition. All the results were well explained by the amorphous AgI aggregate model for the AgI-based fast ion conducting glasses, indicating the appropriateness of the model for the structure of the glasses with high AgI compositions. The formation of the hypothetical bulk amorphous AgI was also indicated in the glasses at the highest limit of AgI composition.This revised version was published online in November 2005 with corrections to the Cover Date.     

液体和非晶态Ni64B36合金结构的从头算分子动力学模拟

运用从头算分子动力学模拟了液体以及猝冷后形成的非晶态Ni₆₄B₃₆合金体系, 得到了它们的对相关函数、结构因子、键对分析方面的结构信息, 与实验结果相当一致; 结果表明, 猝冷得到的合金性质与液体合金性质相似, 为非晶态结构. B原子多数以B—B双原子成键形式分散于Ni原子构成的骨架中. 电子态密度分析表明, Ni 3d电子最活泼, 因此在合金中Ni为活性位. 轨道电荷分析从电子结构角度揭示了在NiB 催化剂中B作为修饰剂的机理.     

Thermal coefficient of linear expansion of non-crystalline chalcogenides in the As-S-Se-Te-I system

The object of the paper is an investigation of the glasses of the (As₂S₃)_x(AsSe_0.5Te_0.5I)_100-x. type for 65≤;x≤;95, using methods of thermomechanical analysis. Values of the thermal coefficients of linear expansion in solid and visco-plastic phase were determined. it was shown that introducing arsenic-sulfide in glass-matrix AsChI, i.e. (AsSe_0.5Te_0.5I), leads to an increasing stability of these glasses. The characteristic temperatures of softening Tg and the temperature of the beginning of deformation t_w increase by increasing content of As₂S₃. The analytical forms of dependence of four significant physical values α_g, α_l, Tg, Tw, as a function of As₂S₃ content in the structure of glasses were fitted. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal evolution of ferromagnetic metallic glasses

A traditional TG apparatus was modified by placing two permanent magnets producing a controlled magnetic field (TG(M): Magneto Thermogravimetry). This technique proved to be useful to study both structural relaxation and crystallisation of ferromagnetic metallic glasses. Results obtained for the amorphous alloys Fe₄₀Ni₄₀P₁₄B₆ and Fe_62.5Co₆Ni_7.5Zr₆Nb₂Cu₁B₁₅, are reported in this paper. Structural relaxation can be evaluated by measuring changes in Curie temperature induced by thermal treatments. Crystallisation in TG(M) is detected through a change in the measured apparent mass (difference between the sample mass and magnetic force driving it upward). These results were confirmed by DSC analysis. Whether the obtained crystalline phase is ferromagnetic, it can be identified through its Curie temperature, measured by TG(M). In fact the value of 770°C measured as Curie temperature of crystallised Fe_62.5Co₆Ni_7.5Zr₆Nb₂Cu₁B₁₅led to conclude that the only ferromagnetic crystalline phase is a-Fe. These hypothesis was confirmed by XRD analysis, showing that the first crystallisation yields to a-Fe nanocrystals. This revised version was published online in July 2006 with corrections to the Cover Date.     

非晶态合金催化剂用于二甲基紫脲酸加氢反应

二甲基紫脲酸加氢反应;nicob/白炭黑催化剂;非晶态合金催化剂     

聚苯乙烯非晶区结构的RDF研究

本文介绍了以X-射线衍射法测定非品区结构的径向分市函数RDF方法，并将其应用于聚苯乙烯（PS）非晶区的结构研究．     

代铬刷镀层的耐腐蚀机理的考察

对新型的代铬刷镀层Ni-Fe-W-P-S进行了耐腐蚀性能机理的分析研究。用扫描电镜(SEM)、透射电镜(TEM)、扫描隧道显微镜(STM)、X射线衍射及电子能谱(XPS)等的分析表明，基体组织为非品结构是代铬刷镀层优异耐腐蚀性的主要原因.     

Study of the Crystallization of an Aromatic Poly-ether-ketone (PK99) by Calorimetric and X-ray Analysis

An analysis of the crystallization behaviour of a new poly(aryl-ether-ether-ketone-ketone), PK99, by differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) is presented. Isothermal crystallization TG were obtained in the whole range between the glass transition temperature (T _g) and the melting temperature (T _m) as a consequence of the slow crystallization kinetics stemming from the closeness of these transitions. The calorimetric results, compared with WAXD data, were applied to determine the theoretical melting temperature and crystallization enthalpy. The DSC and WAXD data were combined in order to calculate the total amount of the crystallizable fraction of the polymer, and a model was proposed to explain the difference between the fractions of crystallinity observed with these techniques. The thermal and X-ray data were also correlated with different lamellar morphologies arising from the crystallization conditions. Finally, DSC experiments on the crystallized sample were used to detect the presence of a rigid amorphous phase which does not relax at T _g. This revised version was published online in July 2006 with corrections to the Cover Date.     

New method for calculating the adsorption of noble gases on amorphous surfaces

A new approach to calculating the equilibrium characteristics of the adsorption of noble gases on the amorphous surfaces of adsorbents was developed and applied to the Ar−TiO₂(rutile) system. Intermolecular adsorbate-adsorbate interactions are taken into account for the nearest neighbors in the quasi-chemical approximation. The lattice energy parameters of all interactions of the model are determined from the Lennard-Jones potential (12-6). The formation of amorphous TiO₂(rutile) surface includes completion of the surface layers and partial removal of the surface oxygen ions. The quality of the amorphization procedure was confirmed by the experimentally measured heats and isotherms of adsorption of the system under study. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1109–1118, June, 1997.     

Ni-B和Ni-Ce-B超细非晶态合金的退火晶化及其催化性能

 采用XAFS,XRD和DTA方法研究了Ni－B和Ni－Ce－B超细非晶态合金在退火过程中的结构变化及其结构与催化性能的关系．活性结果表明,在退火温度为623K时,Ni－B和Ni－Ce－B样品的苯加氢催化反应转化率最高,分别为63％和81％,0．3％Ce的掺入提高了Ni－Ce－B的催化活性．DTA结果表明,Ni－B超细非晶态合金在598和653K有两个晶化峰,而Ni－Ce－B样品有548,603,696和801K四个晶化峰．XAFS和XRD结果进一步说明,在573K退火时,Ni－B样品晶化生成晶态Ni3B和纳米晶Ni,此时Ni－Ce－B仅有少量晶态Ni3B生成．在673K退火时,Ni－B样品中的Ni3B开始分解生成晶态Ni,同时纳米晶Ni聚集并形成大颗粒晶态Ni,而Ni－Ce－B样品晶化生成晶态Ni3B和纳米晶Ni．在773K和更高的温度退火处理后,Ni－B样品中Ni的局域环境结构与金属Ni箔基本一致,但Ni－Ce－B样品晶化生成的Ni晶格有较大畸变,同时Ni3B并未分解．说明0．3％的Ce对提高Ni－Ce－B样品的稳定性有显著作用．本文首次报道了Ni－B和Ni－Ce－B超细非晶态合金中苯加氢催化活性中心为纳米晶Ni和类似于金属Ni的Ni－B非晶态合金．