Compact directed acyclic word graphs for a sliding window

Suffix trees are a well-known and widely-studied data structure highly useful for string matching. The suffix tree of a string w can be constructed in O(n) time and space, where n denotes the length of w. Larsson achieved an efficient algorithm to maintain suffix trees for a sliding window. It contributes to prediction by partial matching (PPM) style statistical data compression scheme. Compact directed acyclic word graphs (CDAWGs) are a more space-economical data structure for indexing strings. In this paper we propose a linear-time algorithm to maintain CDAWGs for a sliding window.     

Generalized Equilibrium Problems and Generalized Complementarity Problems

From a general minimax inequality or an abstract lopsided saddle-point theorem, we deduce general Karamardian-type equilibrium theorems and generalized complementarity theorems. Our new results extend a number of well-known earlier works of many authors.     

A Facile Synthesis of Ethyl 2,4-Dimethoxy-6-perfluoroalkyl-benzoates via Acyclic Precursors

Introduction Polysubstituted arenes are important intermediates in synthetic medicines and dyestuffs, and the fluorinated analogues are more attractive as a result of their lipo-philicity and the increment of activity.1,2 Therefore, to study the convenient and efficient synthesis of polysub-stituted arenes is valuable in organic synthetic method-ology. We have designed a simple synthesis of fluori-nated polysubstituted arenes through the intramolecular Wittig reaction of a new phosphorous ylid…     

镧系与二甘醇-二-(邻羟基苯基)醚配合物的合成与表征

本文合成14种镧系高氯酸盐及硝酸盐分别与二甘醇-二-(邻羟基苯基)醚(记为EO_2(HOP)_2,EO=ethylene oxide,HOP为邻羟基苯基)形成的新配合物,确证组成为Ln(ClO_4)_3·EO_2(HOP)_2·nH_2O(Ln:La-Eu,n=10,Ln:Gd,Dy-Tm,Y,n=7),La_3(NO_3)_9·(EO_2(HOP)_2)_2·3H_2O及La(ClO_4)_2·EO_2H(OP)_25H_2O。文中研究了配合物红外,紫外、~1HNMR谱及~(13)C纵向弛豫时间T_1等,并讨论了共存阴离子、溶剂及配体不同端基对成配的影响。     

高氯酸稀土Sm(Ⅲ)开环冠醚(EO4)配合物的晶体结构

The crystal of title compounds belongs to orthorhombic system with space group P2₁2₁2₁ (No.19). The cell parmeters are a=1.432 16(3) nm, b=1.457 20(3) nm， c=3.005 85(6) nm, and V=6 273.0(2) nm³, Z=8, μ(Mo Kα)=22.21 cm^-1， D_c=1.802 g·cm^-3, F(000)=3 416.00, Finally R₁=0.033 and wR₂=0.073 (I>2.00σ(I)), S=1.023. Every center atom Sm(Ⅲ) is surrounded by the two aether chains, the title compound has ten-coordinate structure and the coordination polyhedron shows a Bicapped Square Antiprism. In the crystal, the title compound has the flack of double moleculars and non-symmetry. The anion ClO₄^- does not take part in the coordination. CCDC: 238709.     

Liquid-liquid extraction of copper (I) and copper (II) as ion-paired complexes with acyclic 2-thienyl-containing polythioether and triphenylmethane dye anion

Three acyclic polythioethers containing 2-thienyl units at both ends were synthesized and the effect of substituent on the extraction of copper(II) was studied. The methyl groups in the terminal thiophene ring have imparted an appreciable degree of increase in the percent extraction of copper(II), while the introduction of chlorine atoms into the 2-thienyl unit resulted in the reverse effect. Among the counter dye anions examined, tetrabromophenolphthalein ethylester was the best one for copper(II) extraction. The composition of extracted species was evaluated to be 122 (Cu(II)/polythioether/dye anion). Quantitative extraction of copper(I) was attained as complexes with various triphenylmethane dyes, i.e., bromocresol green, bromothymol blue, bromo-phenol blue and pyrogallol red. Copper(I) in organic phase was completely back-extracted with 2 mole/l sulfuric acid containing 10% hydrogen peroxide.     

Crumpled laminations and manifolds of nonfinite type

Using a group-theoretic construction due to Bestvina and Brady, we build -manifolds which admit partitions into closed, connected -manifolds but which do not have finite homotopy type.

     

新的酚型开链冠醚及由其衍生的二苯并冠醚的合成

将水杨醛与碱和氯甲基甲基醚反应, 再经过NaBH4还原, 即制得邻(甲氧基甲氧基)苯甲醇, 然后将其在DMF中与NaH和二(或三)甘醇二对甲苯磺酸酯反应, 得开链冠醚1a和1b。1a和1b经稀酸水解, 即脱保护而分别生成新的酚型开链冠醚2a和2b。用2a与二甘醇二对甲苯磺酸酯和NaH在DMF溶液中反应, 合成顺型二苯并-20-冠-6(3); 而2a与环氧氯丙烷在NaOH水溶液中反应, 则合成了17-羟基二苯并-18-冠-5(4)。     

Cathodic synthesis of esters of 1,1,2,2-cycloalkanetetracarboxylic acids derived from 1,1,2,2-ethane- or ethylenecarboxylate esters

The cathodic electrolysis of esters of 1,1,2,2-ethane- or ethylenetetracarboxylic acids in the presence of dihaloalkanes leads to esters of 1,1,2,2-cycloalkanetetracarboxylic acids.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 217–220, January, 1992.     

［La（EO_3）_3（H_2O）］（ClO_4）_3·H_2O的晶体结构

稀土高氯酸盐开环冠醚三缩乙二醇（ＥＯ_３）［Ｌａ（Ｃ_６Ｈ_（１４）Ｏ_４）_３（Ｈ_２Ｏ）］（ＣｌＯ_４）_３·Ｈ_２Ｏ，单斜晶系，Ｐ２_１／ｃ空间群。晶胞参数为：ａ＝１５．４７４（２），ｂ＝１１．３８６（１），ｃ＝２０．８４１（４），β＝９９．８２（１）°，Ｖ＝３６１８（１），ＭｏＫα，Ｚ＝４，Ｄ_ｃ＝１．７１８ｇ／ｃｍ３，μ＝１．４９９ｍｍ￣（－１）。全矩阵最小二乘精细修正，结构因子Ｒ＝０．０５６，Ｒ_ｗ＝０．０８３。中心原子Ｌａ与开环冠醚醚链上的Ｏ（１）～Ｏ（９）及一个水分子形成１０配位双帽四方反棱柱结构。弱配体高氯酸根不参加配位。