查找使用阿拉丁产品的科研文献

Novel phosphorous–nitrogen containing poly(aryl ether ketone)s: synthesis, characterization, and thermal properties

Xuexia Xie,Zhou Wang,Kun Zhang,Jing Xu

Polychlorinated biphenyls and their different level metabolites as inhibitors of glutathione S-transferase isoenzymes

Xingguo Tian,Erqun Song,Ruxian Pi,Xiaokang Zhu,Lichao Liu,Xiaoyan Ma,Hui Dong,Jing Liu,Yang Song

Research on the effects of polychlorinated biphenyl (PCB) toxicity tends to focus on commercial PCB congeners and parent PCBs themselves. However, studies have suggested that PCB metabolites may be more interesting than the parent compounds because of their high reactivity. As a key metabolic enzyme, glutathione S -transferases (GSTs) are responsible for detoxification by catalyzing the conjugation reaction of glutathione (GSH) to xenobiotics. Inhibition of GST activity indicates reduced detoxification ability. We investigated the inhibition of chicken liver GSTs by parent PCBs and their metabolites and observed dose-dependent inhibition in vitro ; inhibitory efficiency declined in the order GSH-conjugate   >   mono-hydroxyl ≈ quinone ≈ hydroquinone   >   parent PCB. Structure–inhibitory activity relationship studies indicated that with the inhibitory activity greatly increases with the number of GSH moieties or chlorine substituents on the quinone ring. However, no significant linear relationship was observed for chlorine pattern changes on the phenyl ring. The reversibility of PCB metabolite inhibition of GSTs is discussed. PCB mono-hydroxyl, hydroquinone and quinone forms showed irreversible inhibition of GSTs, which suggests a mechanism involving covalent binding to cysteine residues in the GST active site. PCB glutathionyl conjugates showed reversible GST inhibition, implying non-covalent binding. Furthermore, reactive oxygen species did not significantly affect GST activity.

Mn2+-doped Zn–In–S quantum dots with tunable bandgaps and high photoluminescence properties

Sheng Cao,Jialong Zhao,Weiyou Yang,Chengming Li,Jinju Zheng

In the present work, we reported the synthesis of Mn2+-doped Zn–In–S quantum dots (QDs) with high optical performance in a controlled manner. The effects of the temperature, the introduced ODE-S amount and Zn/In ratios in the raw materials, as well as the Mn2+ doping concentrations on the photoluminescence (PL) properties of Mn2+-doped Zn–In–S QDs were investigated systematically. The resultant QDs exhibit tunable bandgaps ranging from 2.9 to 3.7 eV, well-resolved Mn2+ d–d emission with a PL quantum yield (QY) of 56% and a surprisingly long excited state lifetime up to ∼4.2 ms, suggesting their excellent PL properties. Meanwhile, the initial high PL QY of the obtained Mn2+-doped Zn–In–S QDs in organic solvents could be preserved very well once they were transferred into aqueous media via ligand exchange. Furthermore, the as-synthesized QDs exhibit excellent thermal stability up to 200 °C in a crude solution.

IL-derived N, S co-doped ordered mesoporous carbon for high-performance oxygen reduction

Wenxiu Yang,Xiaoyu Yue,Xiangjian Liu,Junfeng Zhai,Jianbo Jia

A highly efficient N, S co-doped porous carbon ORR catalyst was simply designed in our report from ordered mesoporous carbon (OMC) and trace ionic liquids (ILs). The microstructure OMC was chosen as the template for improving the specific area, confining the ILs in the mesopores, and promoting the formation of the planar N and S doping. The resulting IL/OMC (IOMC) nanostructure exhibits comparable ORR activity and better stability than the commercial Pt/C catalyst in 0.10 M KOH solution, which makes it one of the best-performing metal-free carbon ORR catalysts. We deduced that the excellent ORR activity is attributed to the synergistic effect of N, S, and the ordered mesoporous structure. Interestingly, the ORR activity can be further boosted in both basic and acidic solutions after Fe doping into the IOMC nanostructures which clearly emphasizes that transition metal Fe is important for the construction of ORR active functional sites especially in acidic solution.

Efficient hybrid solution strategy to fabricate Cu(In,Ga)(S,Se)2 solar cells

Yong Cui,Zhe Zhang,Xu Du,Wei Liu,Shi Liu,Yulin Deng,Xiaogu Huang,Gang Wang

Hybrid solution process is a powerful liquid deposited strategy merging the advantage of molecular precursor solution and nanocrystals ink. A novel hybrid solution approach is presented to fabricate Cu(In,Ga)(S,Se) 2 (CIGSSe) absorber layer using fully dissolved CIGS precursor solution and the CIGS nanocrystals. Such attractive strategy could significantly improve the single deposited thickness and enhance the quality of as-prepared CIGS film compared with the pure CIGS molecular precursor solution and the CIGS nanocrystals ink. Photovoltaic absorber layers based on CIGSSe chalcopyrite structure show the high-quality microstructural performance and are incorporated into solar cells with power conversion efficiency of 10.19%. The high performance of resulted optoelectronic devices represents a chance to extend the hybrid solution process to other inorganic semiconductor thin film solar cells.

Molecular weight analysis of water-soluble poly(phenylene ethynylene)s using MALDI-TOF MS

Jiatao Wu,Chunyan Tan,Xinwen Zhou,Ying Tan,Pengyuan Yang,Yuyang Jiang

Molecular weights of seven poly(phenylene ethynylene)-based water-soluble conjugated polyelectrolytes (CPEs) obtained through Sonogashira coupling are determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A standard sample preparation protocol is developed to characterize the seven CPEs using 2,5-dihydroxybenzoic acid as the matrix (M) and AgTFA as the cationization reagent (CR). High-quality MALDI mass spectra are obtained at volume mixing ratios (CPE/M/CR) of 5/5/1 for anionic polymers (P1–P4) and 5/50/1 for cationic polymers (P5–P7). Molecular weight, molecular weight distribution, and end-group information are analyzed. The effects of molecular weight of CPEs on optical and quenching properties are also studied. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2537–2543

Effect of vapor pressure on performance of sulfurized polyacrylonitrile cathodes for Li/S batteries

Yonggang Liu,Weikun Wang,Anbang Wang,Zhaoqing Jin,Hailei Zhao,Yusheng Yang

Sulfurized polyacrylonitrile (S@pPAN) composites have been synthesized in a high pressure reactor under certain vapor pressure. According to elemental analysis, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), the hydrogen content and the degree of graphitization in S@pPAN composites decreases with increasing synthesis vapor pressure, indicating that a suitably high vapor pressure is helpful in promoting the reaction between polyacrylonitrile and elemental sulfur and finally making the conductive molecular structure of sulfurized polyacrylonitrile more complete. The results show that the sulfurized polyacrylonitrile composite prepared under 5 MPa vapor pressure (S@pPAN-5) delivers a high initial discharge specific capacity of 1821 mA h g−1 and the capacity remains at 1357 mA h g−1 (616.8 mA h gcomposite−1) after 100 cycles with a retention rate of 88% calculated from the 2nd discharge capacity.

Strong and stiff Ag nanowire-chitosan composite films reinforced by Ag–S covalent bonds

Pan Xiao-Feng,Gao Huai-Ling,Su Yang,Wu Ya-Dong,Wang Xiang-Ying,Xue Jing-Zhe,He Tao,Lu Yang,Liu Jian-Wei,Yu Shu-Hong

High-performance composites containing various kinds of nanofibers as reinforcing building blocks have recently received considerable attention, owing to their superior mechanical properties. One of the effective strategies to reinforce these composites involves strengthening interfacial interactions via covalent bonds. However, in contrast to nanosheets, covalent bonds have been rarely used in nanofiber-reinforced composites. Herein, we report the macroscale fabrication of a series of Ag nanowire (NW)-thiolated chitosan (TCS) composite films via spray induced self-assembly. The obtained films were significantly strengthened by Ag–S covalent bonds formed between the Ag NWs and the thiol groups of TCS. The tensile strength of the optimized Ag NW-TCS film was up to 3.9 and 1.5 times higher compared with that of pure TCS and Ag NW-chitosan (CS) films, respectively.

One-step facile synthesis of monodisperse raspberry-like P(S–MPS–AA) colloidal particles

Yangyi Sun,Yuyong Yin,Min Chen,Shuxue Zhou,Limin Wu

This paper presents a one-step procedure for the facile synthesis of monodisperse raspberry-like polymer colloidal particles by soap-free emulsion polymerization of styrene (S), acrylic acid (AA), and 3-(trimethoxysilyl)propyl methacrylate (MPS). In this method, when S, AA, and MPS are mixed with water and stirred at a certain temperature, raspberry-like P(S–MPS–AA) colloidal particles with uniform shapes and sizes could be obtained in a reliable manner. Both the core particles and the smaller corona particles of core surfaces were formed in situ. A mechanism of formation based on the second nucleation induced by MPS-enriched segments on the core surfaces is proposed.

Porous Si coated with S-doped carbon as anode material for lithium ion batteries

Yue Lu,Zhong Haoxiang,Tang Daoping,Zhang Lingzhi

A novel porous Si/S-doped carbon composite was prepared by a magnesiothermic reaction of mesoporous SiO 2 , subsequently coating with a sulfur-containing polymer-poly(3,4-ethylene dioxythiophene), and a post-carbonization process. The as-prepared Si composite was homogeneously coated with disordered S-doped carbon with 2.6 wt.% S in the composite and retained a high surface area of 58.8 m 2  g −1 . The Si/S-doped carbon composite exhibited superior electrochemical performance and long cycle life as an anode material in lithium ion cells, showing a stable reversible capacity of 450 mAh g −1 even at a high current rate of 6,000 mA g −1 .

Synthesis and characterization of novel copolymers based on 3(S)-methyl-morpholine-2,5-dione

Feng Yakai,Chen Chengbin,Zhang Li,Tian Hong,Yuan Wenjie

A series of novel copolymers were successfully synthesized by ring-opening polymerization (ROP) of 3(S)-methyl-morpholine-2,5-dione (MMD) and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one (MBC) using stannous octoate as catalyst. The copolymers were characterized by means of 1H-NMR and FT-IR spectroscopy. Gel permeation chromatography (GPC) test shows that the average-number relative molecular mass and average-weight relative molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry (DSC) demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.

Transition-metal-free synthesis of imidazobenzothiazines via domino C-S/C-N bond formation

Tu Xingzhao,Zhou Lihong,Li Zhijie,Lei Ning,Zeng Qingle

Abstract The carbon-heteroatom bond formation is an important research field. Transition-metal-free synthesis of medicinally important heterocycles avoids products of transition metal contamination, and thus it is an environmentally friendly and cost-saving process. A transition-metal-free domino C-S/C-N formation for the synthesis of imidazobenzothiazines from 2-mercaptobenzimidazoles and 2-halobenzyl bromides is developed. The desired products were obtained in good to excellent yields. The mechanism of domino nucleophilic substitution (S N 2) and nucleophilic aromatic substitution (S N Ar) is proposed. Graphical abstract