正确理解和应用洛必达法则

本文结合学生在用洛必达法则时较多出现的错误和问题,作了一些分析     

大数定律和中心极限定理在保险业中的重要应用

结合《车祸赔付倍涨,车险保额不涨?》报道,阐述了大数法则和中心极限理论在保险中的重要作用.经过分析计算,当机动车第三者保险金额不超过20万元时,保险公司的预期利润最有保障,这就说明了目前机动车第三者责任险最高只能投保20万元的根本原因.     

Symmetry Reduction, Exact Solutions, and Conservation Laws of （2＋1）-Dimensional Burgers Korteweg-de Vries Equation

Using the classical Lie method of infinitesimals, we first obtain the symmetry of the （2＋1）-dimensional Burgers-Korteweg-de-Vries （3D-BKdV） equation. Then we reduce the 3D-BKdV equation using the symmetry and give some exact solutions of the 3D-BKdV equation. When using the direct method, we restrict a condition and get a relationship between the new solutions and the old ones. Given a solution of the 3D-BKdV equation, we can get a new one from the relationship. The relationship between the symmetry obtained by using the classical Lie method and that obtained by using the direct method is also mentioned. At last, we give the conservation laws of the 3D-BKdV equation.     

Exploring Extra Dimensions in Spectroscopy Experiments

We propose an idea in spectroscopy to search for extra spatial dimensions as well as to detect the possible deviation from Newton＇s inverse-square law at small scale, and we take high-Z hydrogenic systems and muonic atoms as illustrations. The relevant experiments might help to explore a more than two extra dimensions scenario in the brane world model proposed by Arkani-Hamed, Dimopoulos, Dvali （ADD） and to set constraints for fundamental parameters such as the size of extra dimensions.     

A New Method to Measure the Divergence of X-Ray Beams from Capillaries

A new method to measure the divergence of x-ray beams propagated out from several capillaries is introduced, This new method is based on Bragg＇s law and is proven efficiently by the experimental measurement with collimators and straight polycapillaries.     

关于复合函数求导法则的探讨

对复合函数求导法则的证明作了讨论，并指出该法则在特殊极限求法中的应用。     

Johnson法则在成组加工排序中的推广

成组技术（Group Technology）是把工件分组进行加工,以提高生产效率的一种生产组织方法,本文把两台机器同序作业（同顺序流水作业）排序问题F2│perm│C_(max)的John-son法则推广到成组加工上,提出确定组与组之间顺序的最优法则,给出了这个问题成组加工的最优排法,并分析算法的计算复杂性。     

双组分冷模射流流化床气化炉内流体动力学特性模拟

针对实际工业生产中经常遇到的多组分体系，本文选取了具有代表性意义的非等密度/直径的双组分体系(树脂和砂子)为研究对象，以Goossens等提出的平均物性法则计算了固体混合物的平均粒径和平均密度，采用欧拉－欧拉计算流体动力学模型(CFD)模拟了二维冷模射流床气化炉内，诸如气、固相流场的时空分布、时均空隙率分布、射流穿透深度等流体动力学的时空特征，所得结果与文献报道相吻合。     

Cell Volume Effect on the Ferroelectric Stability of Perovskite Oxides PbTiO3 and BaTiO3 from First Principle Calculation

Electronic structure of ferroelectric PbTiO3 and BaTiO3 is calculated by the full potential linearized augmented plane wave method. The total energy as a function of the displacement of Ti-cation is obtained for PbTiO3 and BaTiO3 at different cell volumes. At experimental cell volume, Ti-displacement lowers the total energy and the ferroelectricity is stable. When the cell volume is reduced to 90%, total energy is increased with Ti-displacement and ferroelectricity will disappear. The cell volume effect is also confirmed by comparison of the density of states of Ti and O at different cell volumes.     

“二项式定理”教学设计的比较研究与改进

前不久,笔者有幸参加了宁波市高中数学课堂教学评比活动,讲授了"二项式定理"这节课.准备过程中,笔者收集了大量资料,在同组教师的悉心帮助下,对这节课进行了深入的研究.笔者收集来的课件与教学设计主要有三种设计思路,这三种思路总体上都是采用探究式的教学方式,但其中某些环节的设计不太自然,其实质是教师设计好思路让学生去做形式上的探究,是一种伪探究;另外某些环节的设计不太符合学生的认知规律.笔者对它们进行了改进,在设计上有所创新,并且在此次活动中取得了较