The effect of Emetine on macromolecular synthesis in synchronizedTetrahymena pyriformis

Zusammenfassung Emetin hemmt die synchronisierte Teilung vonTetrahymena pyriformis, verhindert die rasche Aufnahme von Aminosäuren und verursacht offenbar eine Zellteilungshemmung.

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This work was supported in part by grants from the Hawaii Heart Association and the Julius and Dorothy Fried Foundation.     

煤中微量元素和矿物富集的同沉积火山灰与海底喷流复合成因

煤中常量、微量元素和矿物的富集往往是多种地质因素共同作用的结果. 运用低温灰化、X射线衍射分析、带能谱仪的扫描电子显微镜、逐级化学提取、电离耦合等离子体质谱等方法对云南砚山晚二叠世煤的矿物学和地球化学特征进行了研究, 提出了煤中微量元素和矿物富集的同沉积火山灰与海底喷流复合模式(或成因类型). 研究发现, 砚山矿区M9煤层硫分含量很高(S_t,d = 10.65%), 属于超高有机硫煤(S_o,d = 9.51%). 矿物组成主要有b-石英副像、透长石、钠长石、白云母、伊利石、黄铁矿以及少量的高岭石、斜长石、钙镁黄长石、金红石和片钠铝石. 煤中高度富集的微量元素有F(841 μg/g), V(567 μg/g), Cr(329 μg/g), Ni(74 μg/g), Mo(204 μg/g)和U(153 μg/g). 该煤中的矿物质主要有3个来源: (1) 高温石英、透长石、白云母和伊利石等是泥炭聚积期间酸性火山灰降落到泥炭沼泽后的产物; (2) 钠长石和片钠铝石以及以上超常富集的微量元素是在泥炭聚积期间, 基性-超基性海底喷流侵入到闭塞缺氧的泥炭沼泽中所致; (3) 稀土元素, Nb, Y, Zr和TiO₂等亲石元素来源于盆地南部的越北古陆. 除了物源供给以外, 砚山矿区煤的矿物学和地球化学异常是同沉积酸性火山灰和基性-超基性海底喷流共同作用的结果.     

循环赛图K(i)2n与边矩阵K''''2n的K-边着色

为了让一个2n阶的完全图K2n变成一个可用于循环赛安排的循环赛图K(i)2n,给出了边矩阵和循环赛图的定义,提出了利用边矩阵K'2n的k-边着色求求解完全图K2n的k个完备匹配Mi的算法.介绍了循环赛图K(i)14,K(i)16,…,K(i)32的构造结果及其应用.     

Matched glass-to-Kovar seals in N2 and Ar atmospheres

The oxidation of Kovar alloy was investigated, the wetting and spreading behavior of hard and soft glasses on Kovar alloy were studed by using the sessile drop method, and the quality and the seal strength of glass-Kovar seals were tested. The experimental results indicated that the preoxidation of Kovar alloy for approximately 10 min at 700°C in air resulted in excellent adherence in glass-Kovar seals. The wetting and spreading behavior of glass on preoxidized Kovar alloy were superior to that on nonoxidized Kovar alloy. The wetting ability of ASF110 glass, at 950°C and 980°C in Ar and N₂ atmospheres, was significantly superior to that of ASF200R and ASF700 glasses. The seal quality of the glass-preoxidized Kovar seal was superior to that of the glass-nonoxidized Kovar seal. The shear strength of the ASF110 glass-preoxidized Kovar seal, which was prepared at 980°C for 20 min in an Ar atmosphere, was approximately 3.9 MPa.     

Structure evolution of Y2O3 nanoparticle/Fe composite during mechanical milling and annealing

Fe-25 wt% Y2O3composite powders have been fabricated by mechanical milling(MM) Fe powders of 100 μm in diameter and Y2O3nanoparticles in an argon atmosphere for the milling periods of4,8,12,24,36,and 48 h,respectively.The features of these powders were characterized by using X-ray diffraction(XRD),scanning electron microscopy(SEM),electron probe micro analyzer(EPMA) and transmission electron microscopy(TEM).The experimental results showed that the mean particle size and crystalline size of MM powders decreased with the milling time increasing.All the elements distributed homogenously inside the powders after 48 h of MM.The lattice constant of the matrix α-Fe kept constant with the milling time,and no solid solution took place during MM process.After 8 h of MM,the α-Fe in each powder became nanocrystalline.After 48 h of MM,Y2O3changes from nanostructure into amorphous structure,and the crystalline size of α-Fe further decreased to 10 nm.The Y2O3in the powders mechanically milled for 48 h kept the amorphous structure after being annealed at 400 1C,and starts to crystallize when the powders are annealed at 600 1C.The amorphous Y2O3contains a small amount of Fe,and crystalline FeYO3appears at 800 1C.     

Steiner三连系的构造与计数

提出了2t 1阶Steiner三连系的构造方法和计数方法,阐述了完全三分图及完全二分图在组合设计中的应用。证明了关于2t 1阶Steiner三连系存在和构造方面的定理。介绍了7×20个19阶Steiner三连系构造的全过程。     

由含化合物体系的二元相图提取活度

本文提出，一种由化合物体系的二元相图提取组元活度数据的新方法，在该方法中，组元的活度系数是组成的函数，用该式计算Mg-Sn体系的活度表明，它与实验值符合较好。     

关于四元数矩阵迹的若干不等式

本文证明了关于四元数矩阵迹的一些不等式,它们是[5]、[6]的相应结果的推广。