SYNTHESIS AND CHARACTERIZATION OF AROMATIC LIQUID CRYSTALLINE COPOLYESTERS WITH REGULAR SEQUENCE STRUCTURE

Several novel aromatic liquid crystalline copolyesters with regular sequence structure were prepared by melt Sehotten-Baumann polycondensation via complex monomer. Polarizing microscope with hot stage, thermal analysis and X-ray diffraction were used to investigate the structure and properties of the copolyesters. The effects of structural units, such as flexible spacer, noncolinear meta-linked phenylene unit, crankshaft unit, kink with flexible bridging unit and various substituted benzene rings on melting temperature of aromatic copolyesters were studied and discussed on the basis of crystalline structure of the polymers.     

4,6-二甲基-N-苯基-2-嘧啶胺的低温热容和热力学性质

通过小样品精密自动绝热量热计测定了合成并提纯的 4,6 二甲基 N 苯基 2 嘧啶胺 (嘧霉胺 )在 78～ 3 91K温区的摩尔热容 .量热实验发现 ,该化合物在 3 63～ 3 72K温区 ,有一固 -液熔化相变过程 ,经三次重复测量 ,得其熔化温度、摩尔熔化焓及摩尔熔化熵分别为 :( 3 70 78± 0 0 8)K ,( 2 1 2 3 3± 0 0 13 )kJ·mol-1 和 ( 5 7 2 7± 0 15 )J·mol-1 ·K-1 .通过分步熔化法得到该物质绝对纯样品的熔点为 3 71 0 3 1K .用差示扫描量热 (DSC)技术对该物质的固 -液熔化过程作了进一步研究 ,结果与绝热量热法一致     

高效液相色谱法附蒸发光散射检测器同时测定烟用接装纸中7种甜味剂的含量

取接装纸样品剪碎成5mm×5mm的小片,称取2.000 0g用水20mL摇床振荡萃取35min,所得萃取液经0.22μm滤膜过滤,取其滤液进行高效液相色谱分析,用蒸发光散射检测器检测。选用ZORBAX SB C18色谱柱为固定相,进样量为10μL。用不同比例的(A)甲醇(每升中含三氟乙酸0.1mL,pH 4.5)和(B)水的混合液作为流动相进行梯度洗脱。在此条件下,所测定的7种甜味剂可达到有效的分离。以7种甜味剂所给出的峰面积对其相应的质量浓度绘制标准曲线,其线性范围均在75～400mg·L~(-1)之间,其检出限(3s)在0.65～9.06mg·L~(-1)之间。在已知样品的基础上加入3个浓度水平的标准溶液后,按试验方法进行回收试验,测得其回收率在89.9%～115%之间,测定值的相对标准偏差(n=5)在0.35%～2.3%之间。     

直观显示摩擦力实验的改进

对文献^[1]中用弹簧秤直观显示摩擦力的实验进行了改进，成功地解决了原实验在滑动摩擦力的测量过程中不易读数的问题。     

Energy transfer processes in phycobilisome model complex at 77 K

Ultra time-resoived huorescence spectra were used to study the energy transter processes and mechanism of complex PEC/PC/APC at 77 K, which was reconstructed with phycobiliproteins (PEC, PC and APC) of Anabaena variabilis, and has intact light-harvesting system and single terminal emitter. The energy transfer relationships between different chromophores especially between rod and core were also discussed based on fluorescence decay kinetic under different detected wavelengths. As a result, we got the possible energy transfer pathways and transfer time constants to be 29 ps between two PEC trimers, 12 ps between PEC and C-PC, 51 ps between rod and core.     

形式三角矩阵环的特殊性质

We consider the sufficient and necessary conditions for the formal triangular matrix ring being right minsymmetric,right DS,semicommutative,respectively.     

国外钢铁分析近况

对国外应用于钢铁分析的方法包括原子光谱法、分光光度法、电化学法以及中子活化法等的现状(主要在1990～2010年间发表的文献)作了综述(引用文献78篇)。     

洛伦兹-哈肯激光混沌系统有限时间稳定主动控制方法研究

研究了洛伦兹-哈肯激光混沌系统基于主动控制方法的有限时间稳定问题. 在研究Terminal 吸引子的基础上, 考虑系统不确定性, 提出一种基于Terminal 吸引子且具有动态主动补偿特性的主动控制方法, 使受控洛伦兹-哈肯激光混沌系统近似实现有限时间稳定.同时, 为解决系统不确定性问题, 设计了一种新的观测器, 并使这种观测器能在很短时间内跟踪系统的不确定性.通过引入奇异扰动性理论, 详细地分析了闭环系统近似有限时间稳定性.仿真实验结果验证了该主动控制方法及观测器的有效性.     

Novel high-sensitivity coherent transceiver for optical DPSK/DQPSK signals based on heterodyne detection and electrical delay interferometer

We present a novel coherent transceiver for optical differential phase-shift keying/differential quadrature phase-shift keying （DPSK/DQPSK） signals based on heterodyne detection and electrical delay interferometer. A simulation framework is provided to predict a theoretical sensitivity level for the reported scheme. High sensitivity of -45.18 dBm is achieved for 2.5-Gb/s return-to-zero （RZ）-DPSK signal, and high sensitivities of -36.83 dBm （I tributary） and -35.90 dBm （Q tributary） are observed for 2.5-GBaud/s RZ-DQPSK signal in back-to-back configuration. Transmission for both signals over 100 km is also investigated. Experimental results are discussed and analyzed.     

基于竞争优势理论的产业集群形成的量化研究

本文从形成产业集群的竞争成势理论出发,运用多元统计中的主成分分析和聚类分析方法,阐明形成产业集群量化的一般原理,并对河南省18个地区的经济水平进行了区域分类,据此进行综合评价,提出产业集群的培育和区域经济的发展对策。