Five New Aromatic Glycosides from Carthamus tinctorius

Five new aromatic glycosides, 1 – 5 , named as carthamosides B₄–B₈, together with three known compounds, 4′‐(hydroxyphenacyl)‐β‐D ‐glucopyranoside ( 6 ), benzyl‐O‐α‐L ‐rhamnopyranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 7 ), and 4‐(methoxybenzyl)‐O‐β‐D ‐glucopyranoside ( 8 ), have been isolated from the air‐dried flower of Carthamus tinctorius. Their structures were identified on the basis of chemical and spectroscopic methods.     

Thermal Decomposition and Dehydration Kinetics of Tetra(piperidinium) Octamolybdate Tetrahydrate in Air

Thermal decomposition of tetra(piperidinium) octamolybdate tetrahydrate, [C₅H₁₀NH₂]₄[Mo₈O₂₆]·4H₂O, was investigated in air by means of TG‐DTG/DTA, DSC, TG‐IR and SEM. TG‐DTG/DTA curves showed that the decomposition proceeded through three well‐defined steps with DTA peaks closely corresponding to mass loss obtained. Kinetics analysis of its dehydration step was performed under non‐isothermal conditions. The dehydration activation energy was calculated through Friedman and Flynn‐Wall‐Ozawa (FWO) methods, and the best‐fit dehydration kinetic model function was estimated through the multiple linear regression method. The activation energy for the dehydration step of [C₅H₁₀NH₂]₄[Mo₈O₂₆]·4H₂O was 139.7 kJ/mol. The solid particles became smaller accompanied by the thermal decomposition of the title compound.     

A group of 3D graphical representation of DNA sequences based on dual nucleotides

Based on chemical properties of the neighboring dual nucleotides, we reduce a DNA sequence into four 3D graphical representations. Associating with the eigenvalues of the introduced covariance matrix and the introduced measure of similarity, we introduce an approach to make similarity analysis of DNA sequence. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008     

花瓣形YBO3∶Eu3+发光薄膜的制备与表征

本文报道了通过水热合成在AAO模板上组装出花瓣形YBO3∶Eu3+薄膜的研究工作.     

A novel graphical representation of protein sequences and its application

On the basis of information on the evolution of the 20 amino acids and their physiochemical characteristics, we propose a new two-dimensional (2D) graphical representation of protein sequences in this article. By this representation method, we use 2D data to represent three-dimensional information constructed by the amino acids' evolution index, the class information of amino acid based on physiochemical characteristics, and the order of the amino acids appearing in the protein sequences. Then, using discrete Fourier transform, the sequence signals with different lengths can be transformed to the frequency domain, in which the sequences are with the same length. A new method is used to analyze the protein sequence similarity and to predict the protein structural class. The experiments indicate that our method is effective and useful.     

机械合金化制备金属间化合物SbSn及其在原油乳液脱硫中的应用

原油中有机硫化物的增多和重质化[1]在炼制过程中易造成设备腐蚀,同时部分硫氧化生成的SO2排放至大气中,可产生酸雨,对环境造成污染.世界各国对成品油中硫含量的规定日益严格,尤其是在各国燃料结构中占有较高份额的汽油、煤油和柴油.     

Preparation of a graphene-based magnetic nanocomposite for the extraction of carbamate pesticides from environmental water samples

A graphene-based magnetic nanocomposite was synthesized and used for the first time as an effective adsorbent for the preconcentration of the five carbamate pesticides (metolcarb, carbofuran, pirimicarb, isoprocarb and diethofencarb) in environmental water samples prior to high performance liquid chromatography-diode array detection. The properties of the magnetic nanocomposite were characterized by scanning electron microscopy and X-ray diffraction. This novel graphene-based magnetic nanocomposite showed great adsorptive ability towards the analytes. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid some of the time-consuming experimental procedures related to the traditional solid phase extraction. Various experimental parameters that could affect the extraction efficiencies have been investigated. Under the optimum conditions, the enrichment factors of the method for the analytes were in the range from 474 to 868. A linear response was achieved in the concentration range of 0.1-50 ng mL(-1). The limits of detection of the method at a signal to noise ratio of 3 for the pesticides were 0.02-0.04 ng mL(-1). Compared with the dispersive liquid-liquid microextraction and the ultrasound-assisted surfactant-enhanced emulsification microextraction, much higher enrichment factors and sensitivities were achieved with the developed method. The method has been successfully applied for the determination of the carbamate pesticides in environmental water samples.     

包覆型Si/C复合材料的制备及其性能研究

分别采用球磨法和高温热解法制备了Si/C复合材料,XRD、SEM、电化学阻抗谱、循环伏安法和恒流充放电测试表征该Si/C复合材料的结构、形貌和电化学性能.结果表明,相比于球磨法,高温热解HDPE制备的Si/C复合材料颗粒形貌规则,碳的包覆较为均匀,导电性较好,阻抗较小.该复合材料首次嵌锂容量为4495 mAh/g,首次库仑效率65.3% ,从第2周开始库仑电效率都保持在97% 左右,经过100次充放电循环后仍能达到438 mAh/g的可逆容量,具有较好的电化学循环稳定性.     

Synthesis and characterization of novel conjugated polymers based on 3-cyclobutene-1,2-dione moiety

Three novel conjugated polymers bearing 3,4-bis（4-hexylthiophen-2-yl）-3-cyclobutene-1,2-dione unit in their main chain have been synthesized successfully in good yields through Suzuki or Stille coupling reaction.Their molecular structures have been confirmed by FT-IR,¹H NMR and ¹³C NMR.All these copolymers exhibit broad and strong absorption bands in UV-vis region,and their optical band gaps are calculated to be 1.6-2.0 eV.suggesting that they have good coverage with the solar spectrum.These polymers have good thermostability and solubility in common organic solvents.Moreover,all these objective macromolecules possess high electron affinity of～3.8 eV determined from cyclic voltammetry measurement,implying that they are potential n-type polymeric photovoltaic materials.     

The first catalytic asymmetric addition of diethylzinc to aldehyde promoted by chiral thiourea

A series of C₂-symmetric and asymmetric chiral thiourea derivatives were synthesized from commercial L-phenylalanine.All of the new compounds have been fully characterized by IR,¹H NMR,¹³C NMR,MS spectra and elemental analyses.The chiral thioureas were used as chiral ligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc,the corresponding sec-alcohols were gained with excellent enantioselectivities（up to 87.1%ee） and high yields（up to 76.7%） after the conditions were optimized.