利用聚合物乳液合成聚甲基丙烯酸甲酯/二氧化硅纳米杂化材料

通过正硅酸乙酯分别在聚甲基丙烯酸甲酯乳液和四氢呋喃溶液中的溶胶－凝胶反应制备出不同的聚甲基丙烯酸甲酯／二氧化硅复合材料。利用扫描电镜、透镜电镜、差热分析和热失重对试样进行了分析。结果表明，利用聚合物乳液可以获得纳米分散的聚甲基丙烯酸甲酯／二氧化硅复合材料，并且在某种程度上其分散尺度小于利用聚合物溶液获得的复合材料。同时，利用聚合物乳液来制备聚甲基丙烯酸甲酯／二氧化硅杂化材料更有利于凝胶过程中二氧化硅网络的形成。     

Liquid chromatography/mass spectrometry for metabonomics investigation of the biochemical effects induced by aristolochic acid in rats: the use of information-dependent acquisition for biomarker identification

The toxic effects of oral administrations of nephrotoxic and carcinogenic aristolochic acid (AA) to male Sprague-Dawley rats were investigated by using high-performance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometer. Analysis of the urine and plasma samples revealed distinct changes in the biochemical patterns in the AA-dosed rats. After peak finding and alignment, principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) were used for multivariate data analysis. Potential biomarkers were studied by high-resolution mass spectrometry (MS) and tandem mass spectrometry (MS/MS) analyses. The MS/MS spectra of all endogenous metabolites satisfying the pre-defined criteria were acquired in a single information-dependent acquisition (IDA) analysis, demonstrating that IDA was an efficient approach for structural elucidation in metabonomic studies. Citric acid and a glucuronide-containing metabolite were observed as potential biomarkers in rat urine. A significant increase in plasma creatinine concentration was also observed in the AA-dosed rats, which indicated that AA induced an adverse effect on the renal clearance function.     

Disposable ionic liquid coating for headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and xylenes in paints followed by gas chromatography-flame ionization detection

Solid-phase microextraction (SPME) with a disposable ionic liquid (IL) coating was developed for headspace extraction of benzene, toluene, ethylbenzene, and xylenes (BTEX) in paints. The SPME fiber was coated with IL prior to every extraction, then the analytes were extracted and desorbed on the injection port of gas chromatography, and finally the IL coating on the fiber was washed out with solvents. The coating and washing out of IL from the fiber can be finished in a few minutes. This disposable IL-coated fiber was applied to determine BTEX in water-soluble paints with results in good agreement with that obtained by using commercially available SPME fibers. For all the four studied paints samples, the benzene contents were under the detection limits, but relatively high contents of toluene, ethylbenzene and xylenes (56-271 microg g(-1)) were detected with spiked recoveries in the range of 70-114%. Compared to the widely used commercially available SPME fibers, this proposed disposable IL-coated fiber has much lower cost per determination, comparable reproducibility (RSD < 11%), and no carryover between each determination. Considering that IL possess good extractability for various organic compounds and metals ions, and that task-specific IL can be designed and synthesized for selective extraction of target analytes, this disposable IL coating SPME might has great potential in sample preparation.     

Synthesis of a novel methacrylic monomer iniferter and its application in surface photografting on crosslinked polymer substrates

(Methacryloyl ethylenedioxycarbonyl) benzyl N,N‐diethyldithiocarbamate (HEMA‐E‐In) was synthesized and used as a monomer iniferter to develop a novel, photopatternable grafting technology. This molecule functions as both a methacrylic monomer and a photoiniferter (photoinitiator–transfer agent–terminator). The structure of HEMA‐E‐In was characterized by ¹H NMR, Fourier transform infrared, and ultraviolet–visible spectroscopies. In the presence of the monomer iniferter, methyl methacrylate was polymerized by exposure to 365‐nm ultraviolet radiation, confirming the initiation capability of HEMA‐E‐In. After the copolymerization of HEMA‐E‐In into a methacrylate‐based polymer, attenuated total reflectance Fourier transform infrared spectra revealed that the photoiniferter functionality was present at the surface of this polymeric substrate. Photografting of poly(ethylene glycol) monomethacrylate monomer from the surface caused a significant change in the hydrophobicity of the surface as demonstrated by contact angle measurements. The novel monomer photoiniferter HEMA‐E‐In initiates the polymerization of bulk monomer and provides a reactive functionality that facilitates further initiation and polymer modification by the polymerization of different monomers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1885–1891, 2002     

聚甲基丙烯酸甲酯单分子膜的原子力学显微镜研究

报道了利用原子力显微镜（ＡＦＭ）技术对聚甲基丙烯酸甲酯（ＰＭＭＡ）单分子膜进行分子结构水平的观察研究．由ＡＰＭ图像中得到的ＰＭＭＡ单体所占面积与用π－Ａ曲线中换算出液面上ＰＭＭＡＬａｕｇｍｕｉｒ膜中单体的面积符合得很好．从ＡＦＭ图像中可见ＰＭＭＡＬＢ膜中ＰＭＭＡ的线型碳链是与档板（ｂａｒｒｉｅｒ）平行的紧密排列，与ＬＢ提膜方向相垂直．并由此对ＰＭＭＡＬＢ膜的形成过程进行分析．此外，还观察到了在Ｓｉ基底上ＰＭＭＡ直链的卷绕伸直排列形态，初步分析了其形成原因．     

热分析动力学数据处理方法的研究进展

综述了最近几年来用热分析法研究固相反应动力学的数据处理方法的新进展，指出了现有方法的成功与局限性，介绍了几种新的动力学处理方法及一种新的热分析技术。     

Determination of DNA based on localized surface plasmon resonance light scattering using unmodified gold bipyramids

The DNA was determined based on resonance light scattering (RLS) spectrometry and the localized surface plasmon resonance. The gold bipyramids were used as the probes and synthesized by a seed-mediated method. Cetyltrimethylammonium bromide was used as stabilizing agent. DNA can be bound to the gold bipyramids due to electrostatic interaction and aggregates, which results in a strong enhancement of the RLS intensity. Under the optimal conditions, the intensity of RLS is directly proportional to the concentration of DNA in the range from 0.1 to 2.0 μg mL(-1).     

Highly regioselective [3 + 2] annulation of azomethine imines with 1-alkynyl Fischer carbene complexes to functionalized N,N-bicyclic pyrazolidin-3-ones

The highly regioselective [3 + 2] cycloaddition of azomethine imines to 1-alkynyl Fischer carbene complexes has been successfully realized under mild conditions. Oxidative demetalation of the newly formed pyrazolo-pyrazolone carbene complexes with pyridine-N-oxide or ceric ammonium nitrate efficiently afforded pyrazolo-pyrazolone derivatives as well as cycloprop-2-enone and trisubstituted 1H-pyrazoles in some cases, providing a novel route to versatile functionalized N,N-bicyclic pyrazolidin-3-ones.     

Carbon anode materials from polysiloxanes for lithium ion batteries

Three kinds of silicon-containing disordered carbons have been prepared by pyrolysis of polysiloxanes with different amounts of phenyl side groups. X-ray powder diffraction, X-ray photoelectron spectroscopy and electrochemical capacity measurements were performed to study their behaviors. Graphite crystallites, micropores, and silicon species affect their electrochemical performances. All of them present high reversible capacities, >372 mAh/g. Since the graphite crystallites are very small, they contribute very little to reversible capacity. The number of micropores produced by gas emission during the heat-treatment process decides whether they exhibit reversible capacity. Si mainly exists in the form C–Si–O and influences the irreversible capacity. There is no evident capacity fading in the first ten cycles, indicating promising properties for these disordered carbons.     

四氯合锌酸二（正十二烷基铵）晶体相变机理的付里叶变换红外光谱研究

采用变温红外光谱研究了层结构标题配合物的固。固相变机理；相变主要与烷烃链和－ＮＨ＿３极性端基结构变化有关，主要来源于烷烃链的堆积结构和构象的有序。无序变化，同时伴有Ｎ－Ｈ…Ｃｌ氢键强度的降低，由于在高温烃链产生ＧＴＧ＋ＧＴＧ＇和临近端基的ＴＧ构象以及ＧＧ链段，链大量扭曲，形成了烷烃链的“熔化”态，发现同相和异相Ｃ－Ｃ伸缩振动频率对烷烃“链熔化”相变很敏感，可用于表征烷烃链的链长变化。