1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions

Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α, β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.     

高效转换的大功率皮秒脉冲激光器

本文描述我们设计的带抗共振环(ARR)的对撞脉冲锁模(CPM)非稳腔Nd:YAP和Nd:YAG激光器,该激光腔结合了CPM腔脉宽窄、工作稳定和非稳腔输出能量高的特点,是一理想的高功率激光器同时选择了KTP、BBO和LBO等优良非线性晶体作为腔内倍频元件,实现高效倍频转换获得×10mJ和5GW/cm²的高能量和高功率绿光皮秒脉冲输出,倍频转换效率高达(50～70)%.     

Continuous-Time Mean-Variance Portfolio Selection: A Stochastic LQ Framework

This paper is concerned with a continuous-time mean-variance portfolio selection model that is formulated as a bicriteria optimization problem. The objective is to maximize the expected terminal return and minimize the variance of the terminal wealth. By putting weights on the two criteria one obtains a single objective stochastic control problem which is however not in the standard form due to the variance term involved. It is shown that this nonstandard problem can be ``embedded' into a class of auxiliary stochastic linear-quadratic (LQ) problems. The stochastic LQ control model proves to be an appropriate and effective framework to study the mean-variance problem in light of the recent development on general stochastic LQ problems with indefinite control weighting matrices. This gives rise to the efficient frontier in a closed form for the original portfolio selection problem. Accepted 24 November 1999     

Optimization over the efficient set: overview

Over the past several decades, the optimization over the efficient set has seen a substantial development. The aim of this paper is to provide a state-of-the-art survey of the development. Given p linear criteria c ¹x,,c^p x and a feasible region X of R ⁿ, the linear multicriteria problem is to find a point x of X such that no point x' of X satisfies (c¹ x',,c^p x')(c¹ x,,c^p x) and (c¹x',,c^p x')q (c¹ x ,,c^p x). Such a point is called an efficient point. The optimization over the efficient set is the maximization of a given function over the set of efficient points. The difficulty of this problem is mainly due to the nonconvexity of this set. The existing algorithms for solving this problem could be classified into several groups such as adjacent vertex search algorithm, nonadjacent vertex search algorithm, branch-and-bound based algorithm, Lagrangian relaxation based algorithm, dual approach and bisection algorithm. In this paper we review a typical algorithm from each group and compare them from the computational point of view.     

Highly effective peroxidic epoxidation of olefins using hexathiocyanatorhenate(IV) as catalyst and bicarbonate as co-catalyst

In the presence of bicarbonate as co-catalyst hexathiocyanatorhenate(IV) functions as an extremely effective catalyst in the epoxidation of olefins using aqueous hydrogen peroxide as the terminal oxidant.     

A general cone decomposition theory based on efficiency

LetK ₁ andK ₂ be two convex cones in some common vector space. This paper is concerned with the question of finding a good decomposition, with respect toK ₁ andK ₂, of a given element of the Minkowski sumK ₁ +K ₂. We propose the criterion of efficiency as a measure for the quality of a decomposition. This criterion allows us to set up a framework from which a general cone decomposition theory is then derived.Research supported by Dirección General de Investigación Científica y Técnica (DGICYT), under project PS89-0058.     

Alkyl-chain branched effect on the aggregation and photophysical behavior of polydiarylfluorenes toward stable deep-blue electroluminescence and efficient amplified spontaneous emission

Robust branched polydiarylfluorenes are constructed forstable deep-blue electroluminescence and efficient amplified spontaneous emission.     

Epsilon efficiency

This paper considers the extension of -optimality for scalar problems to vector maximization problems, or efficiency problems, which havem objective functions defined on a set .It is shown that the natural extension of the scalar -optimality concepts [viz, given >0, given a solution setS, ifxS there exists an efficient solutiony with f(x)–f(y), and given an efficient solutiony, there exists anxS with f(x)–f(y)] do not hold for some methods used. Six concepts of -efficient sets are introduced and examined, to a very limited extent, in the context of five methods used for generating efficient points or near efficient points.In doing so, a distinction is drawn between methods in which the surrogate optimizations are carried out exactly, and those where terminal -optimal solutions are obtained.The author would like to thank the referees whose thoroughness was extremely helpful for the revised paper.     

On linear repkesentations of moufang loops

Abstract

Black [Black, S. (1999 Black, S. 1999. Which words spell “almost nilpotent?”. J. Algebra, 221: 475–496.  [Google Scholar]). Which words spell “almost nilpotent?” J. Algebra 221: 475–496] defined a class of words which are efficient or which have an efficient result. The variety of residually finite groups defined by a word of this class, like that defined by a positive word, is nilpotent-of-bounded-class-by-bounded-exponent. We introduce a notion of a standard exponent for a homogeneous word and we show that a homogeneous word has an efficient result if and only if its standard exponent is 1. With this we shall improve the main results of Black (1999 Black, S. 1999. Which words spell “almost nilpotent?”. J. Algebra, 221: 475–496.  [Google Scholar]) including its theorem. We also answer its first two open questions.