双金属氰化物在多组分偶联反应中的催化活性(英文)

Several dual metal cyanide catalysts were prepared from potassium ferrocyanide,metal chloride(where metal = Zn2+,Mn2+,Ni2+,Co2+ and Fe2+),t-butanol(complexing agent) and PEG-4000(co-complexing agent).The catalysts were characterized by elemental analysis(CHN and X-ray fluorescence),X-ray diffraction,N2 adsorption-desorption,scanning electron microscopy,Fourier-transform infrared spectroscopy,and UV-Visible spectroscopy.The dual metal cyanide catalysts were used in several acid catalyzed multi-component coup...     

氩气/甲烷/空气介质阻挡放电等离子体的发射光谱诊断

为了获得可燃气体的放电及等离子体发射光谱特性,进一步揭示等离子体助燃作用下燃料在稀燃状态的点火与燃烧特性,在常压下以氩气作为载气对预混的甲烷和空气进行放电研究。实验基于平行板电极射频(13.56 MHz)介质阻挡放电的等离子体发生装置,首先在常压下对体积分数为90%氩气/10%空气的混合气体开展放电研究;再在90%氩气含量不变的情况下,调节空气含量并加入与之能形成燃烧化学当量比Φ＝1的甲烷,氩气/甲烷/空气的混合气体同样能实现稳定而均匀的放电;最后分别在90%氩气含量不变,甲烷和空气在当量比为Φ＝0.4～1.9六种情况下进行放电实验。由光谱仪记录不同放电工况下的发射光谱信息,诊断反应产物类型,利用观测到的氮分子第二正带系(0-2)380.4 nm和(1-3)375.4 nm处的发射谱线,与自编程序计算的模拟谱线拟合,得出分子转动温度(即气体温度)。研究结果表明：通过拟合模拟光谱与实验所测发射光谱的方法推测分子转动温度,进而获得气体的平动温度,氩气/空气放电的气体温度可达到1 150 K,氩气/甲烷/空气Φ＝1时放电气体温度升高到1 390 K;甲烷与空气形成不同当量比时,所测等离子体气体温度相对于90%氩气/10%空气混合气体温度的温升在70～240 K范围变化;由光谱信息观测到CH,H,OH和CH₂O等活性粒子的存在以及气体温度的升高,表明可燃成分混合气在射频电场放电作用下发生等离子体燃烧化学反应并释放出化学热。     

一种多介质流体计算的三维非守恒型差分格式

Motivated by the need for three-dimensional methods for interface calculations we describe a 3D non-conservative difference scheme in Lagrange coordinates for calculating multi-component fluid dynamics, according to the thoughts of 2D non-conservative difference scheme and making use of difference method of characteristic and Upwind form. Furthermore, we give a three-dimensional numerical simulation of explosion in concrete, and the results of simulation are consistent with examination.     

可压缩多介质流动的间断有限元方法

采用间断有限元方法、LS方法和通量装配技术相结合,建立了一种计算可压缩多介质流动的有效 方法。计算中以光滑Heavside函数构造流体比热比和重新初始化方程中的符号距离函数,并采用通量装配 技术抑制界面附近的非物理振荡。为解决可压缩多介质流动提供一种新的手段。     

Invariants of Multi-Component Ermakov Systems

It is shown that certain multi-component Ermakov systems admit Lewis-Ray-Reid invariants. This extends the result to the two-component Ermakov system.     

阶梯模冷却Mg_(68)Zn_(29)Y_3合金的组织及准晶相的形成

采用五层阶梯形模具冷却方法在Mg68Zn29Y3合金中制备了二十面体准晶相(I相)。通过扫描电镜、能谱分析仪和透射电子显微分析技术,观察了合金凝固组织和准晶相的形貌,并确定了准晶相成分及结构。结果表明:Mg68Zn29Y3三元合金在普通凝固-阶梯模冷却过程中,冷却速度对准晶相形貌、数量、大小和分布存在较为显著的影响;随着冷速的降低,准晶相的生长方式由细小弥散演变为粗大碎化,准晶晶粒尺寸由20μm逐渐长大至100μm以上;准晶相通过包晶反应形核、长大;合金凝固组织为MgZn+α-Mg+Zn60Mg30Y10。     

The use of reference materials in the finnish industry

Summary A report is given on the results of a survey of the use of reference materials in the chemical industry of Finland. It has been found that there is virtually no production of reference materials in Finland and that most of the materials used are not certified. Mostly, different materials are used which are pharmacopoeia standards with regard to their physical properties. Some companies were found to use more than 100 different reference materials.

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Verwendung von Referenzmaterialien in Finnland

Zusammenfassung Es wird über das Ergebnis einer Umfrage zur Benutzung von Referenzmaterialien in der chemischen Industrie Finnlands berichtet. Es ergab sich, daß in Finnland praktisch keine solchen Substanzen hergestellt werden und die meisten der verwendeten Materialien nicht zertifiziert sind. Meist werden verschiedenartige chemische Substanzen verwendet, die in Bezug auf ihre physikalischen Eigenschaften einem Arzneibuchstandard entsprechen. Einige Firmen benutzen mehr als 100 verschiedene Referenzmaterialien.

Presented at Euroanalysis III conference, Dublin, August 20–25, 1978     

Mathematical models for the processing of data from binding radioassays; transformations and approximations

Ohne Zusammenfassung

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Mathematical models for the processing of data from binding radioassays; transformations and approximations

     

Study of a multi-component system with failure interaction

In this paper we formulate and study a special type of failure interaction, between components, in a multi-component system. We derive expressions for the expected costs of operating the system for both finite and infinite time operation under two different operating policies.