DMSO中Y—Co合金膜的电化学制备

稀土合金作为功能材料，广泛地应用在磁、光、核及超导材料领域．目前一般采用高温或低温熔盐电解及真空镀的方法来制备稀土及其合金材料．如果能在室温下通过电沉积的方法制备稀土合金，则便于控制合金组成，可大大提高它的功效和扩大应用领域．但是，氢的析出使稀土很难...     

ON THE CALCULATION OF MESOPORE SIZE DISTRIBUTION BY THE GAS ADSORPTION METHOD

Seeing that some commercial gas adsorption instrument still uses a too rough method for cal-culation of mesopore size distribution, we reviewed some practical methods of calculation so farproposed in the literature. We have found that most of these methods and many books have someincorrectness in the geometric factor Q_i used for the calculation of pore volume △V_i from corevolume △V_i~k. It has been proved that the correct expression for Q_i should be[_i/(_i~k+1/2△t_i)]~2for cylindrical pores, _i,/(_i~k+1/2△t_i)for slit-shaped pores. On the basis of this correct Q_i,these methods were applied to the desorption isotherms. The results were compared and analyzed.     

Structural differences between a ras oncogene protein and the normal protein

One of the most commonly found transforming ras oncogenes in human tumours has a valine codon replacing the glycine codon at position 12 of the normal c-Ha-ras gene. To understand the structural reasons behind cell transformation arising from this single amino acid substitution, we have determined the crystal structure of the GDP-bound form of the mutant protein, p21(Val-12), encoded by this oncogene. We report here the overall structure of p21(Val-12) at 2.2 A resolution and compare it with the structure of the normal c-Ha-ras protein. One of the major differences is that the loop of the transforming ras protein that binds the beta-phosphate of the guanine nucleotide is enlarged. Such a change in the 'catalytic site' conformation could explain the reduced GTPase activity of the mutant, which keeps the protein in the GTP bound 'signal on' state for a prolonged period time, ultimately causing cell transformation.     

用P538分离富集微量钪

探讨了P-538萃取钪的条件。和Th~(4 ),Ce~(4 )相似,P-538对钪有极好的萃取能力,即使在高酸下也近于完全萃取,因而可用于钪与其它元素(除Th~(4 )与Ce~(4 )外)的分离,萃合物的组成经测定为Sc(HA)_3。     

动态冒险快速定位

利用四变量逻辑函数F(?)全部384条可能最短状态变化过程路径及与之相应的32条逻辑值最短状态变化过程路径,得到了发生实质动态冒险的逻辑函数的一般逻辑结构形式,判定法则等一系列特别重要的规律.能用之快捷、方便计算出F(?)实质动态冒险1748项.为计算机基础研究和迅速发展提供了特别有用的工具和大力的支持.     

“祖”的形义结构及文化蕴涵

谈到"祖"字,必然与"且"和"示"有关."且"的本义从目前的研究情况来看,最具有代表性的意见,一则是认为"且"是"俎"的古文;一则是以"且"为男性生殖器的形象,意指祖先.文章先举例考证二说的不妥,最后从"且"和"示"两方面结合起来研究,"且"至"祖",其所以选择"示"作为明确意义的符号,是寄寓了特有的文化内涵的,反映了对"人之始"的祖先所怀托的尊尚意识.     

论艺术大学图书馆在教学和科研中的作用

分析了艺术大学教学科研对图书馆信息需求的特点，探讨了艺术大学图书馆在教学和科研中的作用。     

关于一类拟凸域的几个性质

关于一类拟凸域的几个性质①童武（首都师范大学数学系北京１０００３７）本文指出一类拟凸域Ｅ的双全纯不变量ＪＥ（（ｚ，ｗ））在边界Ｅ的点上极限的性质和Ｅ的解析自同胎群的性质．这类拟凸域为Ｅ＝Ｅ（ｍ，ｎ，ｋ）＝｛（ｚ，ｗ）∈Ｃｎ＋ｍ：｜ｚ｜２＋｜ｗ｜２ｋ...     

网格理念与高校信息化建设

高校信息化建设工作正在全面展开,这其中技术理念起着重要作用,旧的设计思想使信息化工作出现一些矛盾和困难.网格是高性能计算机和信息服务的战略性基础设施,它将地理上分布、异构的各种资源通过高速网络连接并集成起来,共同完成重大的科研问题.网格为我们提供了一种解决上述矛盾和困难的思维方式,运用网格技术对于全面处理资源共享、人机结合和信息安全等问题,有重大的指导意义.     

厌氧处理结合超声空化高效破解剩余污泥

为了提高超声空化破解剩余污泥的效率,进而提高污泥的可生化性能,提出先进行短时间的厌氧处理,再进行超声空化的破解方案;并对厌氧0~6 d的污泥进行了超声破解实验研究.实验结果显示:随着厌氧时间的增加,污泥自身性质发生较大改变,如化学需氧量(COD)、肽聚糖浓度大幅度增加,p H值明显降低等;对厌氧污泥进行破解,其破解效果优于新鲜污泥:对厌氧6 d的污泥进行破解,其COD浓度是新鲜污泥的99.3倍,是新鲜污泥破解后的9.5倍.厌氧处理可以降低污泥的破解难度,在较大程度上提高超声空化强度,该工艺可以实现高效破解剩余污泥的目的.