用声学诊断方法测量激光等离子体通道的长度与电子密度

用声学诊断方法对超短脉冲强激光在空气中传输形成的等离子体通道进行了测量，根据通道不同位置的声音信号，得到了通道的长度和通道内电子密度等信息. 关键词： 声学测量 等离子体通道     

"庆祝NIST成立100周年"国际研讨会

美国国家标准与技术研究所（NIST）以制作和供应各种标准参与物质（SRM）著称于世。     

双曲空间Hn+p(-1)中具常数量曲率的完备子流形

设Mn是Hn p(-1)中具有常标准数量曲率的n维完备子流形,本文证明了这种完备子流形的某些内蕴刚性定理和分类定理,并对超曲面的情形进行了研究．     

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众所周知，科学家们首选的粒子物理标准模型为：所有物质是由6种夸克——上、下、奇异、粲、顶和底夸克——及比夸克轻得多的粒子，如电子和中微子等构成的。这些粒子的存在已被令人信服的证据所证实。但该模型还需要宇宙中存在有希格斯玻色子（Higgs Boson），希格斯粒子表现为引力，它在某些粒子周围很密集，而在另一些粒子附近则很少。正是这种聚集的密度赋予粒子以质量，因此，夸克很重，电子很轻，而光子则根本没有重量。     

试沦物理知识外化建构中的教学策略

“以学生为中心、发挥学习的自主性”是新课程标准的基本理念之一，现在也有许多的教学文章都谈及这一问题．但纵观实际的课堂教学情境，真正实施的却又很少，在不知不觉中使自己“迷失”成了一种常态，结果课堂教学还是成了教师的“一言堂”．当然，造成这种情况的原因是多方面的，但我想缺乏课堂教学中具体操作的教学策略是主要原因之一．     

Grouped pair-wise comparison for subjective sound quality evaluation

In subjective sound quality pair-wise comparison evaluation, test time grows with square of the number of sound stimulus. For this reason, subjective evaluation of large quantity of stimulus is difficult to carry out with pair-wise comparison method. A grouped pair-wise comparison (GPC) method is proposed to greatly decrease time and difficult of subjective comparison test, in which stimuli in the whole evaluation corpus are divided into N test groups, with reference-link stimuli configured in each group. Derived from subjective results of each group, final results of all stimuli are reconstructed, and their perceptual attributes of sound quality can be analyzed. With car interior noise as example, realization of subjective sound quality evaluation with GPC method is introduced. The results of GPC evaluation are in good agreement with those obtained from paired comparison and semantic differential methods.     

亚纯函数的一个正规定则

We proved:Let F be a family of meromorphic functions in a domain D and a≠0,b∈C.If f′(z)-a(f(z))~2≠b,f≠0 and the poles of f(z)are of multiplicity＞=3 for each f(z)∈F,then F is normal in D.     

Analysis of characteristics of broadband matching for piezoelectric ceramic transducer

Characteristics of broadband matching for piezoelectric ceramic transducer are fully analyzed. It is stated that in the case of without an all pass function, good matching characteristics of maximum bandwidth and gain-bandwidth product are implied in the Butterworth matching theorem. If the parameterσ< .252, it is not helpful to add an all pass function to the circuit following the rule of minimizing center frequency and maximizing gain-bandwidth product.     

面对差异个体的数学教学

2001年制定的《全日制义务教育数学课程标准》（以下简称《新课标》），如今已六年时间了．自2002年起作者一直参与省级中小学骨干教师的培训工作．在学习贯彻实施《新课标》的过程中，在与那些第一线的骨干教师的接触和交谈中，个体差异及其教学是谈论最多的话题之一．作者意识到学生个体差异这个问题与《新课标》的贯彻实施关系密切．这里就面对差异个体的数学教学谈一点粗浅看法，请专家、老师、同仁给予指正．[第一段]