Viscometric study of poly(vinyl chloride)/poly(vinyl acetate) blends in various solvents

The intermolecular interactions between poly(vinyl chloride) (PVC) and poly(vinyl acetate) (PVAc) in tetrahydrofuran (THF), methyl ethyl ketone (MEK) and N,N^′-dimethylformamide (DMF) were thoroughly investigated by the viscosity measurement. It has been found that the solvent selected has a great influence upon the polymer-polymer interactions in solution. If using PVAc and THF, or PVAc and DMF to form polymer solvent, the intrinsic viscosity of PVC in polymer solvent of (PVAc+THF) or (PVAc+DMF) is less than in corresponding pure solvent of THF or DMF. On the contrary, if using PVAc and MEK to form polymer solvent, the intrinsic viscosity of PVC in polymer solvent of (PVAc+MEK) is larger than in pure solvent of MEK. The influence of solvent upon the polymer-polymer interactions also comes from the interaction parameter term Δb, developed from modified Krigbaum and Wall theory. If PVC/PVAc blends with the weight ratio of 1/1 was dissolved in THF or DMF, Δb<0. On the contrary, if PVC/PVAc blends with the same weight ratio was dissolved in MEK, Δb>0. These experimental results show that the compatibility of PVC/PVAc blends is greatly associated with the solvent from which polymer mixtures were cast. The agreement of these results with differential scanning calorimetry measurements of PVC/PVAc blends casting from different solvents is good.     

多色蓝在核酸分子上的Langmuir聚集吸附

用微相吸附-光谱修正（MPASC）新技术研究核酸与多色蓝(PCB)探针分子间的相互作用，分析核酸分子内双静电膜的形成与Langmuir吸附的关联性.通过pH 7.24的介质核酸-PCB反应的光谱研究，测定了结合产物的物理化学参数：结合比1PCB:2DNA-PCB、1PCB:3RNA-PCB, 平衡常数KDNA-PCB=5.42×104， KRNA-PCB=2.82×104,摩尔吸收系数ε(DNA-PCB, 625 nm)=5.65×103（mo1－1•L ）•cm－1， ε(RNA-PCB, 625 nm)=3.85×103 （mol－1•L）•cm－1.结果表明， RNA分子仅形成约60％双螺旋结构链，核酸双螺旋每一周期的负静电沟最大聚集10个PCB分子.该吸附反应用于核酸样品测定，结果良好.     

二苯并三氧二氮穴醚及其Na(Ⅰ)、Cu(Ⅱ)和Co(Ⅱ)配合物的合成与表征

自从1969年Lchn等合成穴醚[2,2,2]似来.人们对穴醚的研究越来越感到兴趣.由于空腔效应,穴醚具有很强的配位能力和较高的选择性,它对于研究无机离子在生物体内的传输过程具有重要的意义,而且有可能用于离子的识别和分离.     

液/液界面生长法制备一维纳米硒

采用均相反应界面生长法制备了一维结构的纳米硒。在制备过程中,初始硒纳米粒子首先在均相反应液中生成,然后加入与该反应液不互溶的溶剂,使其形成液液界面,硒纳米粒子聚集在界面上生长为一维结构。用扫描电镜、透射电镜、X射线粉末衍射等测试技术对样品进行了表征,并讨论了界面生长的机理及其影响因素。     

Cu-13.9Al-4Ni合金的热弹性马氏体相变内耗峰

采用不完全相变内耗测量法研究了Cu-13.9Al-4Ni合金在热弹性马氏体相变时其相变内耗峰与外界变量的依赖关系.当测量频率较低时,完全相变法所测量的单一内耗峰被成功分解成双峰,即高温内耗峰和低温内耗峰.低温内耗峰位置对应于相对动力学模量的最小值,高温内耗峰则对应于相对动力学模量的拐点位置,且呈现出明显的反常振幅效应.     

High-temperature dielectric properties of Gd2CuO4 ceramics

A sample of Gd₂CuO₄ (GCO) has been prepared through the solid state reaction technique. Dielectric properties of this material have been measured in detail as functions of temperature (between 285 and 450 K) and frequency (20 Hz-10 MHz). A step-like increase below 330 K and a broad peak around 360 K were observed in the real part of the permittivity (ε′) which were found to be originated from the oxygen vacancy hopping motions that cause a dipolar relaxation, followed by a Maxwell-Wagner relaxation as the hopping carriers are blocked by the interfaces and surfaces of the sample.     

Metal complex with terpyrindine derivative ligand as highly selective colorimetric sensor for iron(Ⅲ)

A new metal complex[MnL₂]（NO₃）₂·CH₃CN（1） was synthesized by reaction of 4’-4-（l,2,4-triazol-l-yl）phenyl -2,2’:6’,2"-terpyridine（L） with manganese nitrate.The structure of the complex was determined by X-ray crystallography.The results of UV-vis studies showed that the complex exhibits colorimetric sensing ability for Fe³⁺,which can be observed by naked eye.     

Joint Remote Preparation of a Class of Four-Qubit Cluster-Like States with Tripartite Entanglements and Positive Operator-Valued Measurements

In this work, a novel scheme is proposed to realize joint remote preparation regarding a class of four-qubit cluster-like entangled states based on optimal positive operator-valued measurements. To obtain the preparation of desired states, two tripartite non-maximally entangled states are taken as quantum channels, and devoted to building the robust connections amongst the states’ senders and receiver. It turns out that the present scheme enables one to achieve joint remote state preparation with certain success probability (SP) and unit fidelity. Moreover, several nontrivial issues are discussed, including the improvement of SP and the correlation between SP and the employed channels.     

An intrinsic fiber ring laser based sensor with saturable absorber

A novel configuration of fiber ring laser acoustic sensor, which adopts single-mode fiber as sensing element, is proposed and demonstrated. Linewidth less than 1 kHz is achieved by introducing a segment of erbium-doped fiber in the reflecting arm as saturable absorber. A polarization independent unbalanced Michelson interrogation interferometer and phase generated carrier demodulation technique are adopted to recover signal. Experiments demonstrate that the phase sensitivity is 0.018 rad/nm in good linearity and equivalent minimum detect able length change reaches 19.1 pm.     

The “Fingerprint” of a freshwater microalga Scenedesmus sp. LX1: Visualizing the composition of its soluble algal products

The composition of soluble algal products was visualized by a fingerprint analytical method.