Synthesis and characterization of wholly aromatic poly(azomethine)s containing donor–acceptor triphenylamine moieties

N‐(4‐nitrophenyl)‐4′,4″‐bisformyl‐diphenylamine was synthesized from N‐(4‐nitrophenyl)‐diphenylamine by the Vilsmeier‐Haack reaction. Soluble aromatic poly(azomethine)s (PAMs) were prepared by the solution polycondensation of N‐(4‐nitrophenyl)‐4′,4″‐bisformyl‐diphenylamine and aromatic diamine in N‐methyl‐2‐pyrrolidone (NMP) at room temperature under reduced pressure. All the PAMs are highly soluble in various organic solvents, such as N,N‐dimethylacetamide (DMAc), chloroform (CHCl₃), and tetrahydrofuran (THF). Differential scanning calorimetry (DSC) indicated that these PAMs had glass‐transition temperatures (T_gs) in the range of 170–230 °C, and a 10% weight‐loss temperatures in excess of 490 °C with char yield at 800 °C in nitrogen higher than 60%. These PAMs in NMP solution showed UV‐Vis charge‐transfer (CT) absorption at 405–421 nm and photoluminescence peaks around 462–466 nm with fluorescence quantum efficiency (Φ_F) 0.10–0.99%. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of these PAMs can be determined from cyclic voltammograms as 4.86–5.43 and 3.31–3.34 eV, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4921–4932, 2007     

A New Bibenzyl Glycoside from Dendrobium moniliforme

A new bibenzyl glycoside has been isolated from the stems of Dendrobium moniliforme (L.) Sw.(Orchidaceas).Its structure has been identified on the basis of spectroscopic and chemical methods.     

Synthesis of some chiral liquid crystals and study of the effect of intramolecular hydrogen bonding on the phase behaviour

The synthesis of three new series of chiral Schiff's bases containing benzilideneaniline and 2-hydroxybenzilideneaniline moieties as mesogenic cores is presented. Differential scanning calorimetry, optical polarizing microscopy and X-ray diffraction measurements were used to study the phase transition temperatures and behaviour. The results reveal that most of these materials show chiral smectic mesomorphism.     

光照与彩陶俑表面色变关系的实验研究

本文以秦彩俑表面色彩为研究对象,通过光照实验与色彩变化的色度测量,分析了光照引起彩俑颜料色变的规律,为秦彩俑这一大型重点文物的色彩保护提供了科学理论依据.     

三甲基膦和环氧乙烷的加成产物裂解反应机理的MNDO法研究

文中用ＭＮＤＯ方法研究了三甲基膦和环氧乙烷加成产物裂解反应机理     

THE SCHWARZIAN DERIVATIVE IN SEVERAL COMPLEX VARIABLES(II)

ＴＨＥＳＣＨＷＡＲＺＩＡＮＤＥＲＩＶＡＴＩＶＥＩＮＳＥＶＥＲＡＬＣＯＭＰＬＥＸＶＡＲＩＡＢＬＥＳ（ＩＩ）ＧＯＮＧＳＨＥＮＧＹＵＱＩＨＵＡＮＧＺＨＥＮＧＸＵＥＡＮＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＡｕｇｕｓｔ３０，１９９６．Ｄｅ...     

Dimensional Properties of Fractional Brownian Motion

Let B^α = {B^α（t）,t E R^N} be an （N,d）-fractional Brownian motion with Hurst index α∈ （0, 1）. By applying the strong local nondeterminism of B^α, we prove certain forms of uniform Hausdorff dimension results for the images of B^α when N 〉 αd. Our results extend those of Kaufman for one-dimensional Brownian motion.     

Bi3+和Eu3+在Ca2SiO4中的发光和能量传递

用高温固态反应合成了Ca2SiO4:Bi3+,Ca2SiO4:Eu3+和Ca2SiO4:Eu3+,Bi3+发光体。讨论了不同掺杂量和掺杂种类时Bi3+对Eu3+的5D0-7F1,5D0-7F2发射的影响规律。实验发现,Ca2SiO4:Bi3+在紫外线激发下发出明亮的蓝色光,Ca2SiO4:Eu3+,Bi3+中的Bi3+能将激发能传递给Eu3+,使Eu3+的5D0-7F1和5D0-7F2两种跃迁都大大加强,同时,Bi3+也发出鲜艳的紫色光。     

AN INVARIANCE OF CDF EQUATION

ＡＮＩＮＶＡＲＩＡＮＣＥＯＦＣＤＦＥＱＵＡＴＩＯＮ￥ＴＩＡＮＣＨＯＵＡｂｓｔｒａｃｔ：ＴｈｉｓｐａｐｅｒｐｒｅｓｅｎｔｓａｎｅｗｉｎｖａｒｉａｎｃｅｆｏｒｔｈｅＣＤＦｅｑｕａｔｉｏｎ．Ｕｓｉｎｇｔｈｉｓｉｎｖａｒｉａｎｃｅ，ｔｈｅａｕｔｈｏｒｏｂｔａ...     

取代基效应(SCS)与乙烯-α-烯烃共聚物的序列结构Ⅲ.定量分析

本文在分析乙烯-α-烯烃共聚物序列结构时,把代表共单体反接单元的亚甲基(CH₂)βγ和γδ分别归属给了二元组VV和三元组EEV。与此同时,CH₂-δδ和δδ⁺归属给了二元组EE。表征乙烯长序列的CH₂-δ⁺δ⁺分属二元组EE和三元组EEE,对应峰强度在EE和EEE之间的分配是处理序列分布的关键。在本文中运用序列结构的Bovey关系和Randall统计进行演算,求得了修正值△的数学表达式,严格解和近似解。在规则链条件下得到的近似解与G.J.Ray的结果完全相同。当共单体含量较少时,谱峰强度Iδ⁺δ⁺的分配接近相等。在二元组和三元组的水平上,乙烯-α-稀烃共聚物的¹³C NMR谱中共有十三个峰,属于CH₂的有十个,属于CH的有三个。利用这些谱峰的强度数据可以建立一套计算公式,由此提供共聚物序列结构的全部信息。因此这是一个研究乙烯-α-烯烃共聚物序列结构的普适方法。