Group Theoretic Properties of the Group of Computable Automorphisms of a Countable Dense Linear Order

We compare Aut(Q), the classical automorphism group of a countable dense linear order, with Aut _c (Q), the group of all computable automorphisms of such an order. They have a number of similarities, including the facts that every element of each group is a commutator and each group has exactly three nontrivial normal subgroups. However, the standard proofs of these facts in Aut(Q) do not work for Aut _c (Q). Also, Aut(Q) has three fundamental properties which fail in Aut _c (Q): it is divisible, every element is a commutator of itself with some other element, and two elements are conjugate if and only if they have isomorphic orbital structures.     

复杂轮廓表面激光检测及三维重构技术的研究

基于零件实物样件的几何模型反求技术已成为CAD/CAM领域中的研究热点之一。以航空航天用MJ螺纹为对象 ,对逆向工程中的两大关键技术———表面数字化及三维重构技术进行了分析和研究。提出了用一种新型激光光纤传感器实现复杂轮廓表面的非接触数字化检测方法 ,描述了测量原理。通过二维截面轮廓图重构三维面型 ,初步的实验结果验证了此方法的有效性和实用性     

Optimality Conditions for D.C. Vector Optimization Problems Under Reverse Convex Constraints

In this paper, we establish global necessary and sufficient optimality conditions for D.C. vector optimization problems under reverse convex constraints. An application to vector fractional mathematical programming is also given. Mathematics Subject Classifications (1991). Primary 90C29, Secondary 49K30.     

关于联图K_(2,n)∨P_m的邻点可区别的全染色

一个全染色被称为邻点可区别的如果它满足对任意两个相邻点所关联的色集合不同.本文给出了联图K2,n∨Pm的邻点可区别的全色数并且证明了它满足邻点可区别的全染色猜想.     

Coherence Time Measurement of Picosecond Pulses Using Reverse Saturable Absorption in Lead Phthalocyanine

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Immobilization of RuS2 Nanoparticles Prepared in Reverse Micellar System onto Thiol-Modified Polystyrene Particles and their Photocatalytic Properties

RuS₂ nanoparticles, smaller than 3 nm in diameter, were prepared by H₂S gas injection into the AOT/isooctane reverse micellar solution containing RuCl₃ aqueous solution. The nanoparticle size was found to be independent of the W_o (water content) value of the reverse micellar system, as shown by TEM observation. The recovery and immobilization of the RuS₂ nanoparticles from reverse micelles onto thiol-modified polystyrene particles (PSt-SH) were successfully carried out, by the addition of PSt-SH into the reverse micellar solution under conditions of mild stirring. The resulting composites, PSt-RuS₂, showed photocatalytic activity for H₂ generation form aqueous solution containing 2-propanol and Na₂SO₃ as sacrificial electron donors.     

Applying green analytical chemistry for development and validation of RP-HPLC stability indicating assay method for estimation of fenoverine in bulk and dosage form using quality by design approach

A green and robust reverse-phase liquid chromatographic method has been developed for the determination of fenoverine (FEN), by applying combined principles of green analytical chemistry and quality by design approaches on a Spherisorb C18 column (150?×?4.6?mm, 3?µm) with UV detection at 262?nm. A two level fractional factorial design (2^^7-3) Res IV was used for screening of influential chromatographic factors. The critical method parameters actively affecting critical quality attributes (CQAs) were identified and further optimized using Box–Behnken design. The predicted optimum assay conditions comprised of methanol and ammonium acetate buffer 20?mM, in an extent of 81:19% v/v individually having a flow rate of 1.0?mL/min with a column oven temperature of 33°C. The drug was stressed in hydrolytic, oxidative, reductive, thermal, and photolytic conditions. The developed method was validated successfully. The detector response was linear in the concentration of 0.5–160?µg/mL with a limit of detection (LOD) and limit of quantitation (LOQ) as 0.1 and 0.3?µg/mL, respectively. The % recovery was found to be 99.7%. The analytical method volume intensity value for developed method was 45?mL and the environment assessment tool (EAT) score was 41.07. The method is simple, environmentally benign, rapid, and robust for the determination of FEN in bulk and in its dosage form.     

六阶图Q与星图S_n的积图交叉数

目前关于积图的交叉数的研究已经推广到六阶图与星图的积图.研究得到了一个特殊六阶图Q与n个孤立点nK_1的联图交叉数,然后通过收缩的方法,得到了Q与星图S_n的积图交叉数.     

复合Logistic映射中的逆分岔与分形

利用分岔图，揭示出复合Logistic映射可按倍周期分岔走向混沌，且混沌区中存在混沌危机及逆分岔现象．同时，分析了复合Logistic映射临界点的轨道，给出了复合Logistic映射Mandelbrot-Julia集(简称M-J集)的定义，推广了Welstead和Cromer所提出的周期点查找技术，并利用该技术，构造出一系列复合Logistic映射的M-J集．在此基础上，研究了M-J集的对称性；探索了M集周期区域分布的拓扑不变性；通过定性地建立M集上J集的整体刻画，发现M集包含了J集构造的大量信息．