Synthesis and characterization of in-chain silyl-hydride functional SBR and self-crosslinking elastomer

Functional in-chain silyl-hydride(Si-H) SBR copolymers of 4-vinyiphenyldimethylsilanol(VPDMS) and butadiene were synthesized by living anionic polymerization,in which active group Si-H was not lost and its content was controllable. Corresponding self-crosslinking elastomers were obtained by hydrosilation of Si-H group with vinyl bonds in chain.The copolymers and elastomers were characterized by ~1H NMR,size exclusion chromatography(SEC),Fourier transform infrared (FTIR) spectroscopy,differential scanning calorimetry(DSC),and thermogravimetry analysis(TGA) techniques.     

Synthesis, Structure and Photoluminescence of Two Zinc Carboxyl－ate Polymers with Different Coordination Architectures

The hydrothermal reaction of ZnO with benzene‐1,4‐dicarboxylic add gave Zn·BDC·2H₂O (1) and Zn‐BDC·H₂O (2) (BDC = benzene‐1, 4‐dicarboxylate), respectively. Polymer 1 (C₄H₄O₃ZH_0.5) shows a one‐dimensional zigzag chain structure built up from the alternate connection of tetrahedral ZnO₄ and BDC units. Polymer 2 (C₄H₃O_2.5Zn_0.5) possesses a three‐dimensional framework containing infinite zigzag Zn·Zn·Zn pseudochains generated by five‐coordinate zinc centers and a rectangular channel system including three groups of different straight channels along the [001], [010] and [60–1] directions. The two metal‐organic polymeric compounds exhibit strong photoluminescent emission bands at 402 nm (λ_ex = 260 nm) (for 1) and at 344 nm and 385 nm (λ_ex = 279 nm) (for 2) in the solid state at room temperature.     

NBR/ORGANOMODIFIED BENTONITE INTERCALATED HYBRIDS AND THEIR EFFECTS ON THE TOUGHNESS OF PVC

Hybrids of intercalative nitrile-butadiene rubber/organomodified bentonite (NBR/OMB) were prepared by thelatex intercalation technique. Investigation of their mechanical properties and the microstructore of NBR/OMB showed thatthe organomodified bentonite is an effective toughener for NBR. Transmission electronic microscopy (TEM) and X-rnydiffraction (XRD) tests showed that the NBR macromolecule could be intercalated into the galleries of bentonite.Incorporation of NBR/OMB hybrids as tougheners into poly(vinyl chloride) (PVC) results in a substantial increase in theimpact strength of PVC, but little decrease in its tensile strength and flexural strength, compared to the unmodified PVC.     

Crystal Structures and Magnetic Studies of Naphthalene Derivatives Containing Nitronly Nitroxides

Crystal structures of new nitronyl nitroxide derivatives 1, 2 and 3 were determined with X‐ray diffraction analysis: 1, monoclinic, C₂/c, a = 1.2404(5) nm, b = 0.9730(5) um, c = 2.7049(10) ran, β = 98.189(15)°, V = 3.2315(24) nm³, Z = 8; 2, or‐thorhombic, Pbca, a = 0.61262(2) nm, b = 1.11426(6) nm, c = 2.30543(13) nm, V = 1.57373(13) nm³, Z = 4; 3, monoclinic, P2(1)/n, a=0.64253(4) nm, b=2.55003(17) nm, c = 1.15497(6) nm, β = 95.000(3)°, V = 1.8852(2) nm³, Z = 4. Their magnetic properties were measured with SQUID and analyzed based on their crystal structures with simple singlet‐triplet, modified one dimensional antiferromagnetic chain and modified singlet‐triplet models respectively: 1, J/k_b= ?2.5 K; 2, J/k_b = 7.8 K, θ = 2.8 K; 3, J/k_b = ?0.96 K, θ = 0.21 K.     

FeZSM-5/N2O催化氧化苯制苯酚

苯一步氧化制苯酚,是有机物氧化合成中富有挑战性的研究课题之一。该文着重论述了在FeZSM-5及其一系列沸石催化剂上,应用氧化亚氮作为氧化剂使苯直接氧化制苯酚的研究进展。这一系列催化剂体系的特殊之处在于通过氧化亚氮在沸石分子筛上的分解获得具有催化活性的a－氧。详细讨论了在沸石分子筛上形成特殊结构的铁氧化物作为催化活性中心这一观点。由于这种催化体系对苯直接氧化制苯酚的反应有着很高的选择性,因此,这种比较经济和安全的制备苯酚的方法引起了人们的广泛关注。     

稀土掺杂的(K, Sr)Cl·SiO2复合凝胶的荧光性能

采用sol gel法制备了单掺铕及共掺铕、铈的(K,Sr)Cl·SiO2复合凝胶,研究了复合凝胶的荧光性能。根据荧光测试结果,复合凝胶中,Eu3+在没有还原剂的作用下,可以与基质作用形成还原态的Eu2+,复合凝胶表现出相应的Eu2+荧光性能;研究认为,Ce3+,Eu3+共掺杂时,复合凝胶激发光谱与发射光谱峰位基本不变,但强度有所不同。330nm处的激发光谱明显增强,且发射光谱随Ce3+的掺杂量增加而增强。当Ce3+掺杂浓度为3.0%(原子分数)时,复合凝胶具有最大的荧光发射强度,表明Ce3+具有很好的敏化作用。在Ce3+,Eu3+共掺杂复合凝胶体系中,复合凝胶荧光强度增大的原因既可能是电子转移过程,也可能是Ce3+→Eu2+的能量传递过程所致。     

Determination of asperosaponin VI in dog plasma by high-performance liquid chromatography-tandem mass spectrometry and its application to a pilot pharmacokinetic study

A sensitive and rapid liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method has been developed and validated for the determination of asperosaponin VI in beagle dog plasma using glycyrrhizic acid as the internal standard (IS). Plasma samples were simply pretreated with methanol for deproteinization. Chromatographic separation was performed on a Hedera ODS‐2 column using mobile phase of methanol–10 mm ammonium acetate buffer solution containing 0.05% acetic acid (71:29, v/v) at a flow rate of 0.38 mL/min. Asperosaponin VI and the IS were eluted at 2.8 and 1.9 min, respectively, ionized in negative ion mode, and then detected by multiple reaction monitoring. The detection used the transitions of the deprotonated molecules at m/z 927.5 → 603.4 for asperosaponin VI and m/z 821.4 → 645.4 for glycyrrhizic acid (IS). The assay was linear over the concentration range of 0.15–700 ng/mL and was successfully applied to a pilot pharmacokinetic study in beagle dogs. Copyright © 2011 John Wiley & Sons, Ltd.     

Quantum dot induced phototransformation of 2,4-dichlorophenol, and its subsequent chemiluminescence reaction

We have studied the CdTe quantum dot-induced phototransformation of 2,4-dichlorophenol (2,4-DCP) and its subsequent chemiluminescence (CL) reaction. Quantum dots (QDs) of different size and capped with thioglycolic acid were prepared and characterized by molecular spectroscopy, X-ray diffraction and transmission electron microscopy. In the presence of QDs, 2,4-DCP is photochemically transformed into a long-living light emitting precursor which can react with N-bromosuccinimide to produce CL with peak wavelengths at 475 and 550 nm. The formation of singlet oxygen during the phototransformation process was confirmed by the enhancement effect of deuterium oxide on the CL reaction and the change in the UV spectrum of a chemical trap. The CL intensity is linearly related to the concentration of 2,4-DCP in the range from 0.36 to 36 μmol L^?1, and the detection limit (at 3σ) is 0.13 μmol L^?1.

原子荧光法测定土壤中总汞不确定度的评定

评定了原子荧光法测定土壤中总汞的不确定度.分析了样品从制备到测试的整个过程中各环节对测定结果不确定度的影响,结果表明,影响测定结果相对标准不确定度的最大因素是样品制备过程,其次是重复性条件下的标准偏差,标准物质引入的不确定度最小.在规定条件下,测定结果为(0.146±0.012) mg/kg(k=2).     

锌试剂分光光度法测定壳聚糖含量

利用锌试剂与壳聚糖在一定酸度条件下的特异性显色反应，即其复合物在465nm处吸光度与壳聚糖含量在0～O．04g／L范围内呈现良好的线性关系(R=0．996)，基于此建立了一种简便快速的分光光度法。平均回收率为99．68％。