Synthesis, Characterization and Thermal Decomposition Mechanism of Cetyltrimethyl Ammonium Tetrathiotungstate

The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR）, Ultraviolet visible （UV-Vis） spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis （TG）, differential thermal analysis （DTA） and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption （BET） and scanning electron microscopy （SEM）. The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.     

Synthesis and photovoltaic properties of main chain polymeric metal complexes containing 1,10‐phenanthroline metal complexes conjugating alkyl fluorene or alkoxy benzene by C═C bridge for dye‐sensitized solar cells

Four main chain polymeric metal complexes (P1–P4) based on 1,10‐phenanthroline metal complexes via the Heck coupling have been synthesized and characterized by Fourier transform infrared spectroscopy, ¹H NMR, UV–Vis absorption, photoluminescence spectroscopy, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, elemental analysis, and cyclic voltammetry. To investigate their photovoltaic properties, the dye‐sensitized solar cells based on these polymers dyes are studied, under the illumination of AM 1.5G, 100 mW/cm². The study results show the four polymers exhibit good thermally stable and the solar cells based on them have good device performance, and the maximum power conversion efficiency is up to 0.735% for the solar cells based on P3 with a short‐circuit current (J_sc) of 1.68 mA/cm² and an open‐circuit voltage (V_oc) of 0.62 V. Copyright © 2012 John Wiley & Sons, Ltd.     

M/M/1 queue with <Emphasis Type="Italic">m</Emphasis> kinds of differentiated working vacations

In this paper, we consider an M/M/1 vacation queueing system in which m different kinds of working vacations may be taken as soon as the system is empty. When parameters take proper different values, our model reduces to several classical models already studied in references. By quasi birth and death process and generalized eigenvalues method, we give the distributions for the number of customers and sojourn time in the system. Furthermore, we also give the stochastic decomposition results of such stationary indices.     

轻质油品非加氢脱硫技术*

日益严格的环保法规,对生产低硫、超低硫清洁油品技术提出了更高的要求。传统的加氢脱硫技术存在投资大、运行成本高等问题,因此开发成本低、操作条件温和的非加氢脱硫技术成为一种趋势。本文综述了目前轻质油品非加氢脱硫的相关技术,主要包括氧化脱硫、吸附脱硫和生物脱硫等技术的研究进展;简要介绍了萃取脱硫、络合脱硫、催化裂化脱硫、烷基化脱硫、膜分离脱硫及离子液体脱硫等技术;同时对轻质油品非加氢脱硫技术的应用前景进行了展望。     

过渡金属硫化物催化剂催化加氢作用机理

负载型过渡金属(Co、Mo、Ni、W)硫化物催化剂广泛应用于石油炼制催化加氢过程。为了开发高性能的加氢催化剂,过渡金属硫化物催化剂催化活性相的结构与加氢脱硫性能的关系一直以来是催化研究的热点之一。本文从过渡金属硫化物催化剂的活性相结构和反应物在催化剂表面活性位上的吸附-催化反应机理两个方面阐述了过渡金属硫化物催化剂的催化作用研究进展,并对过渡金属硫化物催化剂催化机理研究存在的争议和未来的研究方向进行了分析。     

Degradation mechanism of green biopolyester nanocomposites with various cellulose nanocrystal based nanohybrids

Oceans and soils have been contaminated with traditional plastic due to its lack of degradability. Therefore, green biopolymer composites reinforced with cellulose nanocrystal-zinc oxide hybrids (ZnO hybrids) with good biodegradation ability provided a positive impact on reducing environmental challenges. In this work, the effect of various morphologies of ZnO hybrids on the biodegradation ability of poly(butylene adipate-co-terephthalate), PBAT) under seawater, soil burial, and UV aging conditions were investigated. Sheet-like ZnO hybrids (s-ZnO hybrid) efficiently enhanced the mechanical, UV-blocking properties and biodegradation ability of PBAT nanocomposite films. Compared to neat PBAT, the best tensile strength of PBAT nanocomposite with 2 wt% s-ZnO hybrid was increased by 15.1%, meanwhile this nanocomposite films showed the highest biodegradation rate after 80 days of soil degradation and 90 days of seawater degradation. Besides, three possible biodegradation mechanisms of green PBAT nanocomposite films were presented, hinting that such PBAT nanocomposite have great promising packaging applications.

Graphic abstract

     

Cascade synthesis of 3-quinolinecarboxylic ester via benzylation/ propargylation-cyclization

Reactions of 2-amino-aryl alcohols with beta-ketoesters catalyzed by a catalytic amount of FeCl3 via tandem benzylation-cyclization produce the corresponding 3-quinolinecarboxylic esters in good to high yields. Extending this methodology to propargylation-cyclization, 2-nitrophenyl propargyl alcohols with beta-ketoesters catalyzed by FeCl3 and SnCl2 also produce the 4-alkyne-3-quinolinecarboxylic esters. The mechanistic details of this benzylation/propargylation and cyclization cascade process are also discussed.     

Investigation of DNA as a catalyst for Henry reaction in water

Double-stranded DNA of natural origin can be used to facilitate nitro-aldol (or Henry) reaction in aqueous solution.     

对一类等待空间有限的抢占优先权排队的分析

讨论M/M/1抢占优先权排队模型, 且假设低优先权顾客的等待空间有限. 该模型可以用有限位相拟生灭过程来描述. 由矩阵解析方法, 对该拟生灭过程进行了分析, 并得到排队模型平稳队长的计算公式, 最后还用数值 结果说明了方法的有效性.     

超高效液相色谱-质谱联用法与气相色谱-质谱联用法分析水性印油印记的主要成分

应用超高效液相色谱-质谱联用技术(UHPLC-MS)与气相色谱-质谱联用技术(GC-MS),对环保水性印油中的主要成分(主要颜料与挥发性物质)进行了定性分析。通过超声提取与离心对样品进行预处理后,在ZORBAX Eclipse Plus Phenyl-Hexyl (50 mm×4.6 mm, 1.8 μm)液相色谱柱,15 mmol/L乙酸铵水溶液-乙腈为流动相,在UHPLC-MS负离子电喷雾电离条件下以选择离子监测模式定性分析染料及颜料;采用HP-INNOWAX (30 m×0.25 mm, 0.25 μm)气相色谱柱进行GC-MS全扫描,定性分析挥发性物质。研究确认水性印油中的主要颜料成分是酸性红R、水溶曙红Y与颜料红112,主要挥发性物质是甘油、1,2-丙二醇等。本方法快速、准确,可以满足物证鉴定工作中对印记的检测需要,有助于法庭科学中对印油印记的种类区分。