A facile synthesis of per (poly )fluoroalkyl substituted α-amino acid derivatives

Initiated by CrCl3/Fe redox couple, per(poly)fluoroalkyl iodides added to methyl a-acetylamino acrylate, giving B-per(poly)fluoroalkyl a-amino acid derivatives in good yields.     

光抽运双光子激光朗之万量子理论

本文采用朗之万量子理论获得光抽运双光子激光具有双光子损耗时的朗之万方程,进一步获得稳态平均光子数、频率牵引、线宽和动态斯塔克效应,对激光增益来源的分析表明,非相干抽运仅有单双光子两步过程有贡献,而相干抽运,除上述过程外还有单双光子一步过程有贡献,而且,上述两个过程都受到负反馈和饱和因子的制约,线宽与稳态平均光子数无关。 关键词：     

FIXED POINTS AND COUPLED FIXED POINTS FOR INCREASING OPERATORS WITH APPLICMIONS TO DIFFERENTIAL INCLUSIONS IN BANACH SPACES

ＦＩＸＥＤＰＯＩＮＴＳＡＮＤＣＯＵＰＬＥＤＦＩＸＥＤＰＯＩＮＴＳＦＯＲＩＮＣＲＥＡＳＩＮＧＯＰＥＲＡＴＯＲＳＷＩＴＨＡＰＰＬＩＣＭＩＯＮＳＴＯＤＩＦＦＥＲＥＮＴＩＡＬＩＮＣＬＵＳＩＯＮＳＩＮＢＡＮＡＣＨＳＰＡＣＥＳＺＨＡＮＧＳＨＩＳＨＥＮＧＡＮＤＨＵ...     

R~n中有界区域上调和函数的积分平均值估计

设={x∈Rⁿ;λ(x<0}是一具有光滑边界的有界区域.给定x₀∈,0-1,m∈N及ε>0足够小,就上的调和函数f证明了和其中M_p(f,r)是f在上的积分平均,grad_jf为f的j次梯度.     

Scattering parameters of a waveguide cross junction loaded with a metallic post in the center

In this paper, the scattering parameters of a waveguide cross junction loaded with a metallic post in the center are analyzed for the first time by using the Method of Lines. The homogeneous boundary condition of the third kind and curved boundary are introduced in the formulation. Numerical results are in good agreement with the experimental data. The scattering parameters at Ka-band and W-band of the cross junctions loaded with metallic posts of different radii are presented. It is shown from the numerical results that loaded with metallic posts is an effective means for adjusting the network parameters of the waveguide cross junction to satisfy some special requirements in the design of millimeter wave components.     

Dirichlet型空间上的乘子

本文主要根据τ与μ的不同取值分三种情况刻划了Cn中单位球上Dirichlet 型空间上的点乘子空间M(Dτ,Dμ),并通过两个函数的构造表明:当τ≤n时,包含 关系M(Dτ)(?)Dτ和当τ>μ,τ>n-1时,包含关系M(Dτ)(?) M(Dμ)是严格的.     

General Information

In this paper, we propose and analyze an SQP-type method for solving linearly constrained convex minimization problems where the objective functions are too complex to be evaluated exactly. Some basic results for global convergence and local superlinear convergence are obtained according to the properties of the approximation sequence. We illustrate the applicability of our approach by proposing a new method for solving two-stage stochastic programs with fixed recourse.     

激光标线的原理和实验

根据几何光学知识分析了激光标线原理.理论和实验表明:激光标线长度与激光光束形状、光学元件形状及材料折射率有关.并讨论了激光标线向两侧扩展的原因.     

Novel aromatic polyamides bearing pendent diphenylamino or carbazolyl groups

Two new diamines, 2,4‐diaminotriphenylamine ( 3 ) and N‐(2,4‐diaminophenyl)carbazole ( 4 ), were synthesized via the cesium fluoride‐mediated aromatic substitution reactions of 1‐fluoro‐2,4‐dinitrobenzene with diphenylamine and carbazole, followed by palladium‐catalyzed hydrazine reduction. Amorphous and soluble aramids having pendent diphenylamino and carbazolyl groups were prepared by the phosphorylation polycondensation of aromatic dicarboxylic acids with diamines 3 and 4 , respectively. The aramids derived from diamine 3 had sufficiently high molecular weights to permit the casting of flexible and tough films. They exhibited excellent mechanical properties and moderately high softening temperatures in the 221–298 °C range. However, the reactions of diamine 4 with aromatic diacids gave relatively lower molecular weights products that could not afford flexible films. For a comparative purpose, the parent aramids derived from m‐phenylenediamine and aromatic diacids were also prepared and characterized. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3302–3313, 2004     

CdZnTe核探测器的蒙特卡罗模拟的初步研究

以CdZnTe核探测器的工作原理为依据,探测器内反应的随机性和反应产生的电子空穴对数目的统计规律为物理模型,应用Visual C + + 自行编制了蒙特卡罗模拟软件.模拟了γ射线在CdZnTe探测器中的响应能谱,并将模拟结果与实际器件的测试结果进行了比较讨论.模拟能谱与实际测得的能谱的主峰符合较好.此外,通过分析⁵⁷Co源辐照下探测效率与器件厚度的关系,可以推测探测效率达到最大时所对应CdZnTe探测器的理想厚度