高升力外形下机翼的位流计算

本文采用第二代低阶面元法给出了一种高升力外形外机翼位流计算方法。     

与剖分相结合的牛顿迭代法

使牛顿迭代法与剖分相结合所产生的新算法显示出: l.几乎可以求出一元复n次多项式的所有根。2.可以求出二元n次多项式的等位线。     

大气动力学方程组的半拉格朗日计算方案的数学研究

通过对大气动力学方程组的半拉格朗日方案的数学分析，得出主要结论如下：(1)说明了Robert的半拉格朗日方案并不是绝对稳定的，通过特征线理论和双曲拟线性方程组解的理论，进一步说明了Robert理论的不正确。(2)通过分析右端项沿轨道积分，给出了一个关于半拉格朗日方案成立的判据。该判据与CLF相仿。(3)根据浅水方程特征理论，发现半拉格朗日方案应包括沿轨道反向积分(大气中慢过程)和沿特征锥积分(大气中快过程)，而已有的方案仅含前一类。因此，今后有必要研究后一类的半拉格朗日方案并研究这两类过程之间的相互作用的计算问题。(4)即使研究沿轨道反向积分问题，其特征跟原方程组解直接有关，因此，不仅仅是一个常微分方程组的问题。而大气动力学方程组的经典解一般仅在小范围成立，并且一维、二维和三维间断均会出现。故大范围反向积分特征线一般是不可能的。     

Some exact solutions of the oscillatory motion of a generalized second grade fluid in an annular region of two cylinders

The velocity field and the associated shear stress corresponding to the longitudinal oscillatory flow of a generalized second grade fluid, between two infinite coaxial circular cylinders, are determined by means of the Laplace and Hankel transforms. Initially, the fluid and cylinders are at rest and at t = 0＋ both cylinders suddenly begin to oscillate along their common axis with simple harmonic motions having angular frequencies Ω1 and Ω2. The solutions that have been obtained are presented under integral and series forms in terms of the generalized G and R functions and satisfy the governing differential equation and all imposed initial and boundary conditions. The respective solutions for the motion between the cylinders, when one of them is at rest, can be obtained from our general solutions. Furthermore, the corresponding solutions for the similar flow of ordinary second grade fluid and Newtonian fluid are also obtained as limiting cases of our general solutions. At the end, the effect of different parameters on the flow of ordinary second grade and generalized second grade fluid are investigated graphically by plotting velocity profiles.     

DFT Study on Some Properties of Polybrominated Phenoxathiin 10-Oxides

With the B3LYP calculation method of density functional theory(DFT)and the 6-31G* basis set,full optimization calculation was made for phenoxathiin10-oxide(PTO)and 135 polybromine phenoxathiin 10-oxides(PBPTOs)with the Gaussian 03 program and molar heat capacity in constant volume(CVθ)value of each molecule in the standard state was obtained.The relation between CVθ and the substitution position and number of bromine atom(NPBS)was studied,and the results indicated good correlation(R2 = 1.000)between CVθ and NPBS of PBPTO compounds.Based on the output file of Gaussian 03 program,molar heat capacity at constant pressure(Cp,m)of PBPTO compounds from 200 to 1,000 K was calculated with the statistical thermodynamics program,and the correlation equation between Cp,m and temperature(T,T-1 and T-2)was obtained with the least-squares method,and the correlation coefficient of the correlation equation(R2)was 1.000.In addition,based on the partition function of each molecule calculated by vibration analysis,the relative rate constant of formation of each molecule was calculated.     

邻近555nm区域目视光谱分析的操作技巧

看谱分析至今在一些机械工厂仍普遍使用,鉴于看谱仪器的生产厂家占有一定的市场份额,在一段时期内还不会被其它的仪器完全取代。本工作介绍了邻近555nm区域目视光谱分析的操作方法。从检测钢铁样品中钼开始,认识或记忆这条钼的谱线,可有助于掌握钼谱线周围的其它元素谱线,具有一定联想的效果,帮助初学者认识、记忆及操作。     

杯芳烃衍生物的合成和性质的研究(Ⅴ)

通过对特丁基杯[4]芳烃的酚羟基的选择性醚化制备了一系列一烃基,1,3-二烃基和四烃基醚,烃基分别含有缩醛、酰胺、氰基等活泼官能团.醚化反应的区域选择性主要取决于使用的碱的种类和反应时间的长短.