一类不定积分的分部积分法

对于被积函数形如x^m（ax＋b）^n的一类不定积分,分别在m或n为正整数时,用分部积分法给出其求解思路,并举例说明．     

谚语背后的概率问题

谚语以其短小精炼而为人熟知,有些谚语背后隐藏着一些概率论的知识.对一些谚语,从概率论的角度进行解释,以扩大对于概率论在生活中的体现的认识,增加学习概率论的兴趣,并加深概率论在生活中应用的理解.     

从北京奥运会看概率在体育中的体现和应用

概率论是从数量上研究随机现象统计规律性的一门数学学科,在科技、管理、经济等领域具有着重要作用.同样,在充满变数的奥运会里面,也有着广泛的应用和体现.从北京奥运会里面的一些问题加以总结,以扩大对于概率论在体育中应用的了解,增加学习概率论的兴趣.     

Ultraheavy quarkonium and its production in multi-TeV hadron colliders

Based on the standard model with two Higgs-doublets, we study physics of ultraheavy quarkonia which are composed of superheavy (such as 4-th generation) quarks. Owing to the strong Higgs-boson exchange force over the gluon exchange force, the situation of the mass levels of such quarkonia becomes drastically different from the ordinary qaurkonia like \(c\bar c\) or \(b\bar b\) . The hyperfine splitting becomes larger than the fine splitting. The production rate of such quarkonia increases largely in multi-TeV colliders. Feasibility for observing such quarkonia is discussed.     

An intelligent agent model

This paper discusses fundamental issues of intelligent agents. Based on a portrayal of agent characteristics a general agent architecture linking aspects of perception, interpretation of natural language, learning and decision-making is provided. Agents built upon this architecture are equipped to handle unknown, open and distributed environments. The paper concludes with a discussion whether or not agents designed in accordance with this architecture exhibit some sort of intelligence.     

Negative refractive index in a four-level atomic system

A closed four-level system in atomic vapour is proposed, which is made to possess left handedness by using the technique of quantum coherence. The density matrix method is utilized in view of the rotating-wave approximation and the effect of a local field in dense gas. The numerical simulation result shows that the negative permittivity and the negative permeability of the medium can be achieved simultaneously (i.e. the left handedness) in a wider frequency band under appropriate parameter conditions. Furthermore, when analysing the dispersion property of the left-handed material, we can find that the probe beam propagation can be controlled from superluminal to subluminal, or vice versa via changing the detuning of the probe field.     

Optical potential approach for positron scattering by metastable 2~3S state of helium

The momentum space coupled channels optical(CCO) method for positron scattering has been extended to study the scattering of positrons by metastable helium for impact energies in the range from the positronium threshold up to high energies. Both the positronium formation and ionization continuum channels are included in the calculations via a complex equivalent local potential. The positronium formation, ionization, elastic and 2~3S–2~3P excitation, and total scattering cross sections are all presented and compared with the available information.     

国际社会性科学议题研究的热点及启示*

近年来社会性科学议题在科学教育研究领域越来越受到重视,运用CiteSpace V,VOSviewer对Web of Science核心合集数据库收录的社会性科学议题研究的167篇相关文献进行可视化分析。从核心作者、核心研究机构、共被引文献、关键词共现等角度,客观地分析进入21世纪以来国内外社会性科学议题研究的热点主题,发现社会性科学议题与科学论证、科学素养、科学风险及决策等相关主题的研究联系密切,社会性科学议题文献主要包括课程内容、教学和学校3个层面的研究思路。在文献的知识图谱分析基础上,从社会性科学议题课程目标聚焦、教学策略应用和教学评价缺位等3个方面获得一些启示。     

红磷/石墨复合材料的制备及电化学性能

研究了一种先通过机械球磨和水热法制得的亚微米红磷,再通过球磨亚微米红磷与石墨得到的块状亚微米红磷/石墨复合材料(smRP/G),并利用扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱分析(XPS)、循环伏安法(CV)等手段其进行了表征。 相对比普通红磷,亚微米红磷更容易通过球磨与石墨复合,能有效提升石墨材料的储锂容量。 为红磷在锂离子电池负极材料上的应用提供了一种思路。 在少量添加红磷的条件下,当红磷质量分数为3%时smRP/G表现最佳(3%smRP/G)。 在100 mA/g电流密度下展示出了1417 mA·h/g的首次放电容量,首次库伦效率67.4%。 并在循环200圈后依然保持着700 mA·h/g的可逆循环容量。