含手性膦配体2-MBPA铂(Ⅱ)配合物的2DNMR

利用一维和二维ＮＭＲ技术,对含有手性膦配体的铂配合物ｃｉｓ－〔Ｐｔ（２－ＭＢＰＡＨ）２Ｃｌ２〕（１）,ｔｒａｎｓ－〔Ｐｔ（２－ＭＢＰＡＨ）２Ｃｌ２〕（２）,ｃｉｓ－〔Ｐｔ（２－ＭＢＰＡ）２〕（３）和ｃｉｓ－〔Ｐｔ（２－ＭＢＰＡ）（２－ＭＢＰＡＨ）Ｃｌ〕（４）进行１Ｈ和１３ＣＮＭＲ谱分析,区分了化合物（３）和（４）,归属了糖苷部分的１Ｈ和１３ＣＮＭＲ谱线,并根据磷和铂及磷与磷的偶合常数确定化合物（３）和（４）是顺式构型     

提高差生学习质量的初步探索

为四化建设的需要,必须提高教育质量。普通中学的重要任务之一就是提高合格率,向社会和上一级学校输送合格的人才。而作为任课教师,就是要让更多的学生能掌握教学大纲所规定的基础知识。     

要引导学生注意克服学习化学的心理障碍

《全日制中学化学教学大纲》在培养学生能力方面,提出了更高的要求。笔者从多年的教学实践观察到,学生学习化学,存在着多种的心理障碍,这些心理障碍直接或间接地影响着学生能力的培养。我们经常可以发现,学生会把很容易的问题答错或使答案走了弯路。究其原因不全在基础知识不扎实,而有的是由于心理抑制。化学教师如能充分重视,引导学生认识和消除心理障碍,则必能事半功倍地提高教学质量和学生的心理发展水平。     

酵母丙氨酸转移核糖核酸3'-端十九核苷酸(58-76)的合成

研究了两个低聚核糖核苷酸的3′-端磷酸化方法.以3′-端带磷酸单酯的低聚核苷酸为供体,用T_4 RNA连接酶将AUUC,CGGA,CUCGUCCA和CCAp等按低的供受体摩尔配比(1∶1.1至1∶2),以87～90％的连接率合成了相应于酵母丙氨酸转移核糖核酸3′-端53～76核苷酸顺序的十九核苷酸AUUCCGGACUCGUCCACCAp.     

Spatial memory enhances the evacuation efficiency of virtual pedestrians under poor visibility condition

Spatial memory is a critical navigation support tool for disoriented evacuees during evacuation under adverse environmental conditions such as dark or smoky conditions. Owing to the complexity of memory, it is challenging to understand the effect of spatial memory on pedestrian evacuation quantitatively. In this study, we propose a simple method to quantitatively represent the evacuee's spatial memory about the emergency exit, model the evacuation of pedestrians under the guidance of the spatial memory, and investigate the effect of the evacuee's spatial memory on the evacuation from theoretical and physical perspectives. The result shows that(i) a good memory can significantly assist the evacuation of pedestrians under poor visibility conditions, and the evacuation can always succeed when the degree of the memory exceeds a threshold(? 0.5);(ii) the effect of memory is superior to that of "follow-the-crowd" under the same environmental conditions;(iii)in the case of multiple exits, the difference in the degree of the memory between evacuees has a significant effect(the greater the difference, the faster the evacuation) for the evacuation under poor visibility conditions. Our study provides a new quantitative insight into the effect of spatial memory on crowd evacuation under poor visibility conditions.     

Ultra-precision figuring using submerged jet polishing

A new removal optimization method called submerged jet polishing(SJP) is reported. Experiments are conducted to obtain the removal shape. Results of SJP indicate that a Gaussian shape removal function can be obtained and that the removal rate is sensitive to variations in the standoff distance. SJP is applied to the corrective figuring of a BK7 optical glass. The flatness is improved from photovolatic(PV) 0.066 λ to 0.024 λ(λ = 632.8 nm) after three iterations,and the root mean square(RMS) value is improved from 0.013 λ to 0.00395 λ. The experimental result indicates that SJP has a capability for ultra-precision figuring and can be applied in polishing complex-shaped surfaces.     

Riemann-Liouville分数阶半线性发展型H-半变分不等式的可解性和最优控制

本文研究了Hilbert空间中半线性Riemann-Liouville分数阶发展型H-半变分不等式的可解性和最优控制.首先,利用不动点理论和Clarke广义次微分性质得到半线性Riemann-Liouville分数阶发展型H-半变分不等式解的存在性.其次,在一般假设条件下证明系统的最优控制存在性.最后,给出一个例子来验证本文的主要结果.     

城镇建设项目规划管理智能辅助决策系统

本文介绍城镇建设项目规划管理智能辅助决策系统研究的阶段性成果。     

半线性椭圆型方程组正解的对称性和单调性

该文讨论了扇型区域上一类半线性椭圆型方程组混合边值问题正解的对称性和单调性．所得结果是文献［1］－［14］的一个推广．