Complexity of some cutting plane methods that use analytic centers

We consider cutting plane methods for minimizing a convex (possibly nondifferentiable) function subject to box constraints. At each iteration, accumulated subgradient cuts define a polytope that localizes the minimum. The objective and its subgradient are evaluated at the analytic center of this polytope to produce one or two cuts that improve the localizing set. We give complexity estimates for several variants of such methods. Our analysis is based on the works of Goffin, Luo and Ye. Research supported by the State Committee for Scientific Research under Grant 8S50502206.     

钢中残量元素As,Sn,Sb的X射线荧光光谱分析

本文介绍了用日本理学3530XRF光谱仪扫描道测定钢中痕量元素As、Sn、Sb。由于短波强大的背景破坏了检测线的线性,通过用DATAFLEX 181B背景扣除的数据处理,消除了这些影响,成功地校准了曲线。方法简单;快速;XRFS结果与化学分析一致,该法已用于炼钢的过程控制和原材料分析。     

应用DV－5 2000型直读光谱仪分析钢中的酸溶和酸不溶铝

本文描述了用火花原子发射光谱分析的方法，应用美国Ｂａｉｒｄ公司ＤＶ－５２０００（ＨＲ－４００光源）直读光谱分析钢中的酸溶和酸不溶铝。实验中采取虚拟酸溶铝分析通道、二次积分的方法进行测定。本法快速简便，所得分析值与标准值吻合，结果令人满意。     

施主中心量子点能谱分析

在有效质量近似下，使用数值矩阵对角化的方法，得到了高斯束缚势下施主中心量子点的能谱，并与简谐势相比较.结果显示施主中心量子点基态及低激发态的性质主要取决于量子点的尺寸、束缚势的强度及形状. 关键词： 施主中心量子点 高斯势阱 能谱     

Efficient and scalable arylation of bicyclic lactones to form quaternary centers using conventional and microwave radiation

Easily accessible bicyclic lactones were efficiently arylated under modified Hartwig and Buchwald conditions to form quaternary aryl centers with complete cis selectivity. This series is notable in that unreactive substrates, including sterically-demanding ortho-substituted aromatic compounds, enjoyed significant rate acceleration under microwave radiation. Additionally, it was noted that the reactions could be accomplished under standard anaerobic conditions and on multi-gram scale.     

高碘酸钠氧化甘油的动力学研究及应用

本文利用紫外分光光度法研究了高碘酸钠氧化甘油的动力学，测定了其动力学方程，探讨了反应机理，同时建立了甘油氧化动力学的紫外分光光度法，该法简单、重现性好、准确度高。     

偏磷酸盐掺杂对KDP晶体生长与光学性能的影响

研究了KDP晶体中散射颗粒形成的一种机理。掺杂微量偏磷酸盐即可使KDP晶体中出现散射颗粒，随着掺杂浓度提高，散射颗粒密度增大。散射颗粒形成的原因在于偏磷酸根具有PO4四面体端基，在晶体生长时容易被生长晶面吸附进入晶格。偏磷酸盐掺杂影响了晶体的光学性能，晶体的光损伤阈值也明显地爱到掺杂的影响。     

Isochronous Centers and Isochronous Functions

Abstract We study isochronous centers of two classes of planar systems of ordinary differential equations.Forthe first class which is the Linard systems of the form =y-F(x),=-g(x) with a center at the origin, we provethat if g is isochronous(see Definiton 1.1),then the center is isochronous if and only if F≡0.For the secondclass which is the Hamiltonian systems of the form =-g(y),=f(x) with a center at the origin,we prove thatif f or g is isochronous,then the center is isochronous if and only if the other is also isochronous.     

测度中心为单点集的强拓扑混合系统

本文用构造性的方法证明了存在强拓扑混合的紧致系统,其测度中心是单点集.从而说明了拓扑混合的系统在拓扑的观点下是复杂的,但在遍历的意义下却可能是简单的.     

印度红花岗石与芝麻白花岗石的光谱的研究

采用了电感耦合等离子体原子发射光谱法、X荧光光谱法测定了印度红花岗石和芝麻白花岗石的组成，测定了它们的X射线谱及红外光谱。印度红花岗中的Fe、Ca和Al、Ti、K、S、P、Mg、Mn的含量分别高于和低于芝麻白花岗石中的Al、Ti、K、S、P、Mg、Mn、Fe、Ca。印度红花岗石的红色是由于它们含有Fe的有色矿物而产生的。