核磁COLOC技术在一类多取代苯结构鉴定中的应用一类多取代苯结构的COLOC鉴定

通过非环前体的分子内成环反应,可合成一类多取代苯,对这类产物进行结构鉴定,有助于了解整个反应历程和机理。但取代基增多,势必导致各结构因素变得复杂,难以从各芳碳的经验计算式去推测各取代基所处的相对位置,而以一般的光、波谱方法也较难获得这类结构信息。实验表明,核磁COLOC技术是确定这类产物各取代基相对位置较为合适的方法,本文以NMR技术对这类产物进行了结构鉴定,并讨论了COLOC技术在确定其各取代基相对位置中的作用;同时通过对产物的结构确认,讨论了产物取代基间的相互作用所导致其芳碳化学位移实测值与经验计算值之间的差异,以及含氟基团对邻位芳碳的碳氟间三键偶合作用。     

On equivalence of derived categories

Let A be an Abelian category and B be a thick subcategory of A. Let D ^b(B) denote the derived category of cohomologically bounded chain complexes of objects in A and D _B ^b (A) denote the derived category of cohomologically bounded chain complexes of objects in A with cohomology in B. We give two if and only if conditions for equivalence of D(B) and D _B ^b (A), and we give an example where D ^b (B) and D _B ^b (A) are not equivalent.     

用修正的RELIEF方法测量高速空气流瞬时速度的理论研究

修正了拉曼激发激光感应电子荧光（ＲａｍａｎＥｘｃｉａｔｉｏｎｐｕｌｓｅＬａｓｅｒ－ｉｎｄｕｃｅｄＥｌｅｃｔｒｏｎｉｃＦｌｕｏｒｅｓｃｅｎｃｅ简称ＲＥＬＩＥＦ）方法，以实现对亚音速和超音速空气流多点时速度的测量，测量精度优于２％。     

光学系统时间畸变和色时间滞后的研究

本文对皮秒和飞秒技术中瞬态现象测量系统所用的特殊光学系统校正时间畸变和压缩色时间滞后的问题进行了讨论。实验证明用该方法设计研制的光学系统校正效果显着。     

饱和光纤中的各阶孤子及孤子相互作用

首先研究了非线性饱和光纤中各阶孤子存在的幅值范围，与标准非饱和情况的非线性薛定谔孤子非常不同，即一阶孤子幅值范围是１．４≤Ｎ≤∵．０，二阶孤子为４．０≤Ｎ≤♀．０，三阶孤子为７．０≤Ｎ≤≤１５．０，并分析了各阶孤子的传输特性，最后研究了双一阶孤子相作用的若干特点，明确了五个方面的特性。     

An analysis of (h,k, 1)-Shellsort

One classical sorting algorithm, whose performance in many cases remains unanalyzed, is Shellsort. Let h be a t-component vector of positive integers. An h-Shellsort will sort any given n elements in t passes, by means of comparisons and exchanges of elements. Let S>_j(h; n) denote the average number of element exchanges in the jth pass, assuming that all the n! initial orderings are equally likely. In this paper we derive asymptotic formulas of S_j(h; n) for any fixed h = (h, k, l), making use of a new combinatorial interpretation of S₃. For the special case h = (3, 2, 1), the analysis is further sharpened to yield exact expressions.     

A simultaneous redox, alkylation, self-assembly reaction under solvothermal conditions afforded a luminescent copper(I) chain polymer constructed of Cu3I4- and EtS-4-C5H4N+Et components (Et = CH3CH2)

A simultaneous redox, alkylation, self-assembly reaction under solvothermal conditions afforded a novel copper(I) chain polymer constructed of luminescent Cu3I4- and unprecedented EtS-4-C5H4N+Et components (Et = CH3CH2).     

Finding the convex hull of a simple polygon

It is well known that the convex hull of a set of n points in the plane can be found by an algorithm having worst-case complexity O(n log n). A short linear-time algorithm for finding the convex hull when the points form the (ordered) vertices of a simple (i.e., non-self-intersecting) polygon is given.     

Phosphine-triggered complete chemo-switch: from efficient aldehyde-alkyne-amine coupling to efficient aldehyde-alkyne coupling in water

[reaction: see text] A phosphine ligand served as a remarkable chemo-switch for the silver-catalyzed reaction of alkynes with aldehydes in the presence of amines in water. Exclusive aldehyde-alkyne-amine coupling product was observed in the absence of phosphine, whereas in the presence of a phosphine ligand, exclusive aldehyde-alkyne coupling product was obtained.     

Synthesis of substituted quinolines by electrophilic cyclization of N-(2-alkynyl)anilines

Quinolines substituted in the 3-position by an iodo or phenylseleno group are readily prepared in good to excellent yields by the reaction of propargylic anilines with appropriate electrophiles under mild reaction conditions. [reaction: see text]