关于C_(11)A_7·CaF_2稳定性的研究

本文采用X射线衍射分析方法,研究了影响C_(11)A_7·CaF_2稳定性的因素,结果表明C_(11)A_7·CaF_2在1450℃以内,能够稳定存在;Mgo,K_2O对C_(11)A_7·CaF_2稳定性没有影响;Na_2O、P_2O_5和CaO能与C_(11)A_7·CaF_2发生反应、分别生成少量NC_6A_3、Ca_5F(PO_4)_3和C_3A,但在硅酸盐水泥熟料的正常煅烧制度下,反应程度较低,对C_(11)A_7·CaF_2稳定性不大.熟料中铝酸盐相存在的形式,主要取决于氟在熟料中的分布,CaF_2掺量较低,温度超过1350℃,C_(11)A_7CaF_2消失,生成C_3A;CaG_2掺量较高时,温度高达1450℃,熟料中的铝酸盐相仍为C_(11)A_7·CaF_2,而不生成C_2A.     

太阳活动11年周期的形成原因新探

太阳活动11年周期的形成原因，是天文学中的一个古老课题，至今没有一个完全令人满意的解释。本文的研究使 “行星引潮力说”再次复活。     

基于网格技术的数字图书馆运行平台设计

简述了网格的概念及特性,分析了它的运行机制,提出了基于网格技术的数字图书馆运行平台设计。     

In vitro protein synthesis and α amylase activity in F cells from hepatopancreas ofPalaemon serratus (Crustacea; Decapoda)

In crustaceans, all the steps in the assimilation of food take place in the hepatopancreas. To facilitate the study of this organ, a method for the dissociation of cell types was developed. The hepatopancreas of the prawnPalaemon serratus was mechanically dissociated and the cells separated by Percoll density-gradient centrifugation. The E and R cells had similar densities of around 1.05 g/ml. The F cells were separated into two distinct fractions with densities of 1.075 and 1.082 g/ml. The B cells sedimented at a density of 1.12 g/ml. The ratio between the two populations of F cells was found to vary during the intermolt cycle while B cells disappeared after the molt. When the density gradient fractions were incubated with³H-leucine, incorporation was highest in the F cell fractions. Measurements of -amylase activity, indicated that the two populations of F cells may be derived from the same cell type.     

Binding of 11-cis retinaldehyde to the partially purified cellular retinaldehyde binding protein from bovine retinal pigment epithelium

Summary 11-cis retinaldehyde binding analysis was performed on a bovine retinal pigment epithelium preparation of cellular retinaldehyde binding protein (CRALBP), whose purity degree was estimated as 75%. Equilibrium binding studies were carried out measuring the replacement of tritium-labeled with unlabeled 11-cis retinaldehyde at 25°C. Analysis of the experimental data both by a direct curve-fitting procedure utilizing a non linear least square regression analysis and by a conventional Scatchard plot revealed a single non-interacting binding site with an apparent equilibrium constant of 0.9×10^–7 M.A binding stoichiometry of approximately 1 mol of 11-cis retinaldehyde/mol of binding protein can be calculated from the experimental data. Competition studies carried out in the presence of unlabeled trans and cis isomers of Vitamin A derivatives confirm the high degree of specificity of the 11-cis retinaldehyde binding.     

Bovine microvascular endothelial cells of separate morphology differ in growth and response to the action of interferon-γ

Five cell types recently isolated from the bovine corpus luteum differed in their epithelioid morphology and their cytoskeleton, but shared common criteria of microvascular endothelial cells^1,2. To give strong evidence for the separate entity, the growth rate of the 5 phenotypically different cells was studied. They were seeded at low density on day 0. Most of these cells were treated with 200 to 1000 U recombinant bovine interferon- (IFN-) for 3 days. The untreated remainder served as controls. Cell counts were made for all cultures on days 4, 7, 10 and 13. morphology: 13 d after treatment with IFN- senescent cells as well as intact cells occurred in cultures of cell types 1 to 4. Cultures of cell type 5 were apparently unchanged and resembled their untreated counterparts. Desminpositive cells in cultures of cell type 2 developed cell processes. Growth rate: In the absence of IFN-, the growth rate was high for cell types 3 and 4, moderate for cell type 1, and low for cell types 2 and 5. The presence of IFN- caused anti-proliferative effects. These were higher for cell types 3 and 4 than for cell types 1 and 2. IFN- could be cytotoxic on cell type 3. In contrast, the cytokine tended to support the cell growth of cell type 5. These findings substantiate the postulate that endothelial cells exhibiting separate morphology in culture also function differently.     

钨砷系列杂多蓝的研究Ⅱ——1∶11钨砷双系列稀土杂多蓝

利用控制电位电解的方法合成了４种未见文献报道的杂多蓝,Ｋ１１Ｈ２〔Ｌｎ（ＡｓＷ１１Ｏ３９）２〕·ｘＨ２Ｏ（Ｌｎ＝Ｌａ,Ｃｅ,Ｐｒ,Ｎｄ）,并利用等离子体原子发射光谱等对其进行了元素组成的分析,利用ＩＲ、ＵＶ、极谱、光电子能谱、电子顺磁共振、热重差热等测试手段,对其结构和性质进行了研究．     

Nα-quinaldyl-L-arginine·HCl,a new defensive alkaloid fromSubcoccinella-24-punctata (Coleoptera,Coccinellidae)

The isolation of N-quinaldyl-L-arginine·HCl (1) from the CoccinellidaeSubcoccinella-24-punctata is reported. The structure, first established on the basis of the analysis of the spectral properties of1, has been confirmed by synthesis. The alkaloid is of endogenous origin and markedly deterrent to ants.     

基于预测有效度的组合预测模型近似求解

在文献[1]的基础上,首先指出了文献[1]算法存在的一些缺陷,然后给出了组合预测方法精度均值E(A)等于各单项预测模型精度序列均值E(Ai)(i=1,2,…,m)的线性组合的一个充分条件,并给出了组合预测精度的上限和下限估计,从而就一般的情况提出了基于预测有效度的组合预测模型新的近似求解方法.最后以文献[1]中的实例说明了本文算法的有效性.并和文献[1]的结果进行了比较分析.     

贫燃条件下钙钛矿型催化剂上C_3H_6催化还原NO_x反应的研究

利用柠檬酸络合法制备钙钛矿型复合氧化物 L a0 .8Ce0 .2 Co XFe1- XO3催化剂 ,研究其在贫燃条件下 NOX 的催化还原性能 .实验表明 :在没有水蒸气存在的条件下 ,在 30 0°C时 ,La0 .8Ce0 2 Co O3催化剂上 NOX 的转化率可达 46.8%,这时还原剂丙稀已完全氧化 ;但在水蒸气存在下 ,La0 .8Ce0 2 Co O3催化剂上 NOX的转化率明显下降 ,同时丙稀的完全氧化温度也上升5 0°C～ 1 5 0°C,这主要是由于水蒸气对反应活性中心竞争吸附的缘故 ;而双取代的催化剂La0 .8Ce0 2 Ce0 .2 Fe0 .8O3和 La0 .8Ce0 2 Co0 .8Fe0 .2 O3催化剂具有相当的催化活性和较好抗水蒸气能力 ,这可能是由于 Ce O2 和 Co Fe O3之间的协同作用增加了氧空位 ,从而弥补了由于水蒸气竞争吸附所导致的活性下降