Optimized prefactored compact schemes

The numerical simulation of aeroacoustic phenomena requires high-order accurate numerical schemes with low dispersion and dissipation errors. In this paper we describe a strategy for developing high-order accurate prefactored compact schemes, requiring very small stencil support. These schemes require fewer boundary stencils and offer simpler boundary condition implementation than existing compact schemes. The prefactorization strategy splits the central implicit schemes into forward and backward biased operators. Using Fourier analysis, we show it is possible to select the coefficients of the biased operators such that their dispersion characteristics match those of the original central compact scheme and their numerical wavenumbers have equal and opposite imaginary components. This ensures that when the forward and backward stencils are added, the original central compact scheme is recovered. To extend the resolution characteristic of the schemes, an optimization strategy is employed in which formal order of accuracy is sacrificed in preference to enhanced resolution characteristics across the range of wavenumbers realizable on a given mesh. The resulting optimized schemes yield improved dispersion characteristics compared to the standard sixth- and eighth-order compact schemes making them more suitable for high-resolution numerical simulations in gas dynamics and computational aeroacoustics. The efficiency, accuracy and convergence characteristics of the new optimized prefactored compact schemes are demonstrated by their application to several test problems.     

微球板电子倍增器基体制备技术研究

新型微球板电子倍增器和微通道板相比具有高增益、无离子反馈、制备简单、造价低廉等优点。介绍了微球板电子倍增器的工作原理、特点和广阔的应用前景。由于微球板基体的形成技术是微球板制备的关键技术，论文从理论上研究了微球板基体烧结过程中的烧结速率。并采用自行设计组分的高铅玻璃，用立式炉成珠设备进行了玻璃微珠的制备。探索了微球板制备过程中玻璃微珠的分级技术、微球板电子倍增器基体成型工艺和技术。制备出基本满足要求的微球板电子倍增器基体。给出了制造的样品和文献上样品结构的SEM对比照片，最后对实验过程中的一些现象进行了分析，并给出了实验的结论。     

石灰石闪蒸改性及脱硫性能的试验研究

本文对3种不同产地的石灰石进行了闪蒸改性处理,对改性石灰石颗粒的孔径分布进行了测定,研究了压力、温度等参数对石灰石闪蒸改性的影响。并在气流反应器上对闪蒸后的样品进行了硫化试验。结果表明,在一定的压力和温度下,闪蒸处理能够增大石灰石颗粒的微孔孔径,并使石灰石样品的脱硫性能得到较大提高。     

高阶Bernoulli多项式和高阶Euler多项式的关系

利用发生函数的方法，讨论了高阶Bernoulli数和高阶Euler数，高阶Bernoulli多项式和高阶Euler多项式之间的关系，得到了经典Bernoulli数和Euler数，经典Bernoulli多项式和Euler多项式之间的新型关系。     

某些类氖离子和类镍离子等离子体状态对应关系的研究

利用一维拉格朗日流体动力学程序Med103详细研究了产生类镍Ag,Cd,In,Sn, Sb离子和类氖Fe,Co,Ni,Cu,Zn离子的等离子体状态.通过对电子温度、离子丰度、离子数密度等状态参量的分析比较，得到了这两类等离子体状态之间的对应关系.即类镍银的等离子体状态与类氖铁 的相近，类镍镉的与类氖钴的相近，依次类推.利用这一对应关系可以方便地由类氖机理x射线激光的等离子体状态来对相应元素的类镍x射线激光的等离子体状态进行判断. 关键词： 类氖 类镍 等离子体状态 x射线激光     

高电荷态Ar^q＋与Ne碰撞中入射离子电荷交换截面的研究

报道Ar^q Ne(q=8，9，11，12)碰撞体系中多电子转移过程，得到了多组实验测量电荷交换截面数据，讨论入射离子电荷交换截面、反冲离子产生截面与入射离子电荷态、能量以及散射离子电荷态的关系，并且将实验结果与Ar^q Ar碰撞体系进行对比研究。在修正分子库仑过垒模型的基础上，对实验现象做了合理的解释。     

Excitons in coupled quantum dots

Properties of excitons in vertically coupled GaAs/AlGaAs quantum dots were investigated using the variational method within the envelope function and effective mass approximations. It was found that when the thickness of the spacer layer becomes less than about one exciton Bohr radius, both the exciton binding energy and the fundamental optical transition energy are reduced compared to those in isolated quantum dots. This is a result of increased space extension of exciton due to the penetration of carrier wave functions into the spacer layer and corresponding reduction in confinement energy which dominates over the Coulomb interaction between the electron and the hole.     

钱氏吴越国与日本的交往及其在中日文化交流史上的地位

五代十国时期,钱氏吴越国积极发展与日本的关系,但日本国对此却持消极的态度,双方的交往主要通过民间进行,局限在经济、文化领域。研究表明,此间中日交流出现了新的动向,即从以前中国方面的单方输出、日本方面的积极接受,开始变为中日双方的双向交流。尽管此时日本的"逆输出"在质和量上都不足道,但这毕竟是值得注意的历史现象,也可称为中日文化交流史上的一个转折点。     

数学课堂教学中创新教育的培养

通过对数学创新教育的内涵、创新素质的培养模式等问题的探讨 ,试图倡导在数学教学中有意识地提高和完善学生的创新意识、创新能力和创新人格     

sl玻色子体系在U(2l+1)O(2l+2)过渡区的严格解

利用无穷维李代数方法得到了相互作用sl玻色子体系在U( 2l+ 1 ) O( 2l+ 2 )过渡区的能谱和波函数的严格解 .给出了该系统Bethe假定方程的数值解法 .