交联苯乙烯/丙烯酰胺共聚微球的制备及其C_(60)功能化初探

以二乙烯基苯 (DVB)为交联剂 ,利用一次投料分散共聚合的方法合成了交联的苯乙烯 (St) /丙烯酰胺 (Am )共聚微球 .实验发现 ,共聚单体Am的投料量和介质的极性对微球的形态有着显著的影响 .在反应过程中交联PS链段和PAm链段发生相分离 ,使粒子产生异形 .随后 ,通过微球上的酰胺基团与C60 的反应 ,将C60 引入微球表面 .初步的光电导性能测试表明 ,带有C60 的微球具有较好的光电导性能     

钯系催化剂上CO气相催化偶联合成草酸二乙酯的原位红外研究

利用原位红外技术在常压分别对ＣＯ气相催化偶联与亚硝酸乙酯反应合成草酸二乙酯在钯系催化剂上的吸附与反应机制进行了研究,发现ＣＯ主要吸附在活性中心钯上,并存在线式与桥式两种吸附形式,研究表明二者之间存在过滤态,线式吸附的ＣＯ更容易参与ＣＯ偶联反应,而桥式吸附的ＣＯ对反应也具有一定的贡献。亚硝酸乙酯在反应温度下性质很活泼,红外光谱证明在催经剂表面上有吸附的ＥｔＯ存在,原位红外反应的研究结果进一步证实了烷氧羰基钯中间配合物的存在,并由此进一步探讨了该反应的机理。     

Chiral activated alkenes induced asymmetric Baylis–Hillman reaction in Me3N/H2O/solvent medium

Chiral‐activated alkenes, L ‐menthyl acrylate and (+)‐N‐α‐phenylethyl acrylamide, induced asymmetric Baylis–Hillman reaction of aromatic aldehydes was realized at 25°C for 7 days in Me₃N/H₂O/solvent homogeneous medium. The corresponding Baylis–Hillman adducts were obtained in good chemical yield with moderate to excellent diastereoselectivity (up to 99% de). © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:317–321, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20209     

反相高效液相色谱法分析刺儿菜中维生素K_1

报道了用高效液相色谱法快速测定刺儿菜中维生素Ｋ１的方法。ＮｏｖａｐａｋＣ１８柱为分离柱,甲醇－异丙醇（７０３０）为流动相。方法操作简便,分离条件较好,回收率在９５％以上,变异系数小于１．２３％。     

A Surfactant-stable Bacillus pumilus K9 α-Keratinase and Its Potential Application in Detergent Industry

An α-keratinase producing strain was isolated with wool as the sole carbon and nitrogen source and identified as Bacillus pumilus K9. The major amino acids liberated from the keratin degradation of wool by B. pumilus K9 were glutamic acid and leucine. The α-keratinase was purified to electrophoretic homogeneity with a molecular weight of 32000. The purified enzyme exhibits an optimum activity at 60 ℃ and pH=9.0. It was stable at pH values between 8 and 11. Bacillas pumilus keratinase displays a high activity towards casein, keratin, wool and feather, which indicates its wide application range. The keratinase was completely inhibited by phenylmethyl-sulfonyl fluoride(PMSF) and β-mercaptoethanol, and moderately inhibited by ethylemediamine-tetraacetic acid(EDTA), sugges-ting it is a metallo-cysteine keratinase. This enzyme could remain stable that could even be promoted in the presence of surfactants, including sodium dodecyl sulfate(SDS), Tween and Triton. And Tween 40 and Triton X-100 could substantially enhance the activity of the enzyme by 54% and 35%, respectively. It may indicate the prominent feature of the keratinase to tolerate surfactants. The enzymatic properties distinguish this keratinase from others in the literature. Furthermore, this enzyme is extremely stable in the presence of a commercially available detergent with 1% concentration. Detergents ARIEL, Bluemoon and WhiteCat can enhance the activity of the keratinase by 43.56%, 15.22%, and 22.48%, respectively.     

Influence ofγ-Fe2O3 nanoparticles doping on the image sticking in VAN-LCD

Image sticking in liquid crystal display(LCD)is related to the residual direct current(DC)voltage(RDCV)on the cell and the dynamic response of the liquid crystal materials.According to the capacitance change of the liquid crystal cell under the DC bias,the saturated RDCV(SRDCV)can be obtained.The response time can be obtained by testing the optical dynamic response of the liquid crystal cell,thereby evaluating the image sticking problem.Based on this,the image sticking of vertical aligned nematic(VAN)LCD(VAN-LCD)with different cell thicknesses(3.8μm and 11.5μm)and different concentrations ofγ-Fe2O3 nanoparticles(0.017 wt.%,0.034 wt.%,0.051 wt.%,0.068 wt.%,0.136 wt.%,0.204 wt.%,and 0.272 wt.%)was evaluated,and the effect of nano-doping was analyzed.It is found that the SRDCV and response time decrease firstly and then increase with the increase of the doping concentration ofγ-Fe2O3 nanoparticles in the VAN cell.When the doping concentration is 0.034 wt.%,theγ-Fe2O3 nanoparticles can adsorb most of the free impurity ions in liquid crystal materials,resulting in 70%reduction in the SRDCV,8.11%decrease in the decay time,and 15.49%reduction in the rise time.The results show that the doping ofγ-Fe2O3 nanoparticles can effectively improve the image sticking of VAN-LCD and provide useful guidance for improving the display quality.     

Electrodes of carbonized MWCNT-cellulose paper for supercapacitor

Journal of Nanoparticle Research - A facile strategy for detecting xanthine in serum samples by copper nanocluster (CuNCs) with high intrinsic peroxidase-like activity was reported. Firstly, a...     

The effect of fullerene on the resistance to thermal degradation of polymers with different degradation processes

Investigations were made about the effect of fullerene (C₆₀) on the resistance to thermal degradation of high density polyethylene (HDPE), polypropylene (PP), polymethyl methacrylate (PMMA), and bisphenol A polycarbonate (PC) matrix by using thermogravimetric analysis coupled to Fourier transform infrared spectroscopy. The results showed that the influences of C₆₀ on the resistance to the thermal degradation of different polymers were dependent on their thermal degradation mechanism. The resistance to the thermal degradation of HDPE, PP, and PMMA were improved with the addition of C₆₀, especially for HDPE matrix, which indicated that the radical trapping played a dominant role. PP and PMMA released more gaseous products at high temperature by the random scission of C–C backbone; owing to the lower bond dissociation energy of C–C in the backbone for the existence of side chains. Meanwhile, the steric hindrance of side chains also made the radicals hard to recombine with each other and accelerated the random scission, leading to the less effect on the resistance to the thermal degradation of PP and PMMA. However, few changes of resistance to the thermal degradation were found in PC matrix with the addition of C₆₀ for its non-radical degradation mechanism.     

Thermal stability and oxygen resistance of polypropylene composites with fullerene/montmorillonite hybrid fillers

Journal of Thermal Analysis and Calorimetry - Silane coupling agent (KH-550) was used to connect fullerene (C60) with montmorillonite (MMT) to prepare C60-decorated MMT hybrid (C60-Si-MMT), and the...