数学试卷评讲课——不容忽视的课

每个教师都必须评讲试卷.如同每个学生都得做试卷一样,试卷是考试内容的载体,是对师生教学情况进行考查的主要工具.教师对试卷的评讲既可检验课堂教学效果,巩固学生平时所学知识,培养学生解题能力,又可了解教学情况,调整教学思路,改进教学方法.数学由于其学科的特点决定了在教学中,试卷评讲会占有一定的课时,是教学的重要环节之一.……     

水溶性苝醌衍生物(13-SO~2Na-DDHA)与胶体半导体(CdS)澡光 诱导电子传递过? 痰亩ρа芯?

根据非均相体系电子传递动力μ＜0(μ=E~s*/s+-E~CB)的原理,构建出相匹配的水溶性苝醌衍生物光敏剂(13-SO~2Na-DDHA)与胶体半导体(CdS)的复合体体系,? 獯忝鸱椒ǎ獬鏊侵浜捅砉劢岷铣Ｊ?K~app)为1480(mol/L)^-1。继而? τ孟孕?spincounteraction)的ESR技术,首次定量地研究了它们之间的光诱? 嫉绱莨痰亩ρВ范耸?3-SO~3Na-DDNA光敏化作用的CdS胶体半导体表? 婀饣乖ρХ匠毯退俾食Ｊ峁⑾郑诒咎逑抵蠺EMPO接受光电子的反应? 妒?,而不同于均相体系中的反应级数别虽在相同可见光照射条件下(13-SO~2Na-DDHA)复合体的光还原速率比单独CdS高约82倍,表明该水溶性光敏剂对CdS胶体半导体具有显著的敏化效果,在太阳能应用中可被用作CdS胶体半导体有效的敏化剂。     

水溶性苝醌衍生物(13-SO~2Na-DDHA)与胶体半导体(CdS)澡光 诱导电子传递过? 痰亩ρа芯?

根据非均相体系电子传递动力μ＜0(μ=E~s*/s+-E~CB)的原理,构建出相匹配的水溶性苝醌衍生物光敏剂(13-SO~2Na-DDHA)与胶体半导体(CdS)的复合体体系,? 獯忝鸱椒ǎ獬鏊侵浜捅砉劢岷铣Ｊ?K~app)为1480(mol/L)^-1。继而? τ孟孕?spincounteraction)的ESR技术,首次定量地研究了它们之间的光诱? 嫉绱莨痰亩ρВ范耸?3-SO~3Na-DDNA光敏化作用的CdS胶体半导体表? 婀饣乖ρХ匠毯退俾食Ｊ峁⑾郑诒咎逑抵蠺EMPO接受光电子的反应? 妒?,而不同于均相体系中的反应级数别虽在相同可见光照射条件下(13-SO~2Na-DDHA)复合体的光还原速率比单独CdS高约82倍,表明该水溶性光敏剂对CdS胶体半导体具有显著的敏化效果,在太阳能应用中可被用作CdS胶体半导体有效的敏化剂。     

一种基于训练数据的迭代改进核函数

To improve performance of a support vector regression, a new method for a modified kernel function is proposed. In this method, information of all samples is included in the kernel function with conformal mapping. Thus the kernel function is data-dependent. With a random initial parameter, the kernel function is modified repeatedly until a satisfactory result is achieved. Compared with the conventional model, the improved approach does not need to select parameters of the kernel function. Sim- ulation is carried out for the one-dimension continuous function and a case of strong earthquakes. The results show that the improved approach has better learning ability and forecasting precision than the traditional model. With the increase of the iteration number, the figure of merit decreases and converges. The speed of convergence depends on the parameters used in the algorithm.