检索结果-南通市图书馆

Miscibility and Crystallization Behavior of Novel Branched Poly(ethylene succinate)/Poly(vinyl phenol) Blends

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2019年第11期37卷 1169-1175页

作者： Kang-Jing Zhang Zhao-bin qiu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

The blends of novel branched poly(ethylene succinate)(b-PES) and poly(vinyl phenol)(PVPh) were prepared v ia a solution and casting method. The miscibility, melting behavior, spherulitic morphology and growth, and crystal structure of b-PES/PVPh blends were investigated in detail. PVPh was miscible with b-PES over the whole compositions as evidenced by the single composition dependent glass transition temperature. Double melting behavior occurred in neat b-PES and b-PES/PVPh 85/15 blend after isothermal melt crystallization, which may be explained by the melting, recrystallization, and remelting mechanism. In addition, the depression of equilibrium melting point of an 85/15 blend was also found, confirming again the miscibility between the two components. The addition of PVPh caused the decrease of nucleation density and crystal growth rates of b-PES spherulites in the blend. The crystal structure of b- PES was unchanged before and after blending;moreover, the crystallinity of b-PES decreased slightly in the blend.

关键词： Polymer blends Miscibility Crystallization behavior

New Numerical Methods for the Coupled Nonlinear Schrdinger Equations

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2010年第2期26卷 205-218页

作者： qiu-bin Xu Qian-shun Chang Department of Applied Mathematics Nanjing Audit University Nanjing 211815 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

In this paper, three numerical schemes with high accuracy for the coupled Schrodinger equations are studied. The conserwtive properties of the schemes are obtained and the plane wave solution is analysised. The split step Runge-Kutta scheme is conditionally stable by linearized analyzed. The split step compact scheme and the split step spectral method are unconditionally stable. The trunction error of the schemes are discussed. The fusion of two solitions colliding with different β is shown in the figures. The numerical experments demonstrate that our algorithms are effective and reliable.

关键词： Coupled nonlinear Schrodinger equation(CNLS) split step Runge-Kutta method compact scheme,split step spectral method difference scheme

Crystallization Behavior and Dynamic Mechanical Properties of Poly(ε-caprolactone)/Octaisobutyl-Polyhedral Oligomeric Silsesquioxanes Composites Prepared via Different Methods

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2020年第2期38卷 158-163,I0006页

作者： Si-Qi Teng Zhi-Guo Jiang Zhao-bin qiu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

Two octaisobutyl-polyhedral oligomeric silsesquioxanes(oib-POSS)reinforced biodegradable poly(ε-caprolactone)(PCL)composites were prepared via two different methods,i.e.,melt compounding and solution casting,which were named as m PCL/oib-POSS and s PCL/oibPOSS,respectively,in this ***-POSS dispersed finely in both composites;moreover,oib-POSS aggregates were larger in m PCL/oib-POSS than in s PCL/*** the different preparation methods,oib-POSS obviously promoted the crystallization of PCL,especially in s PCL/oib-POSS,but did not modify the crystal structure of *** storage moduli of PCL were improved significantly in both ***/oib-POSS composites with enhanced crystallization behavior and improved dynamic mechanical properties were successfully prepared through both methods;moreover,the solution casting method was more effective than the melt compounding method.

关键词： Poly(ε-caprolactone) POSS Crystallization

Bioinspired manganese complexes catalyzed epoxidation for the synthesis of the epoxyketone fragment of carfilzomib

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2019年第3期30卷 698-701页

作者： bin qiu Chungu Xia Wei Sun Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research Institute of LICP Lanzhou Institute of Chemical Physics (LICP) Chinese Academy of Sciences University of Chinese Academy of Sciences

We report herein an efficient catalytic epoxidation reaction for the synthesis of epoxyketone(tert-butyl((S)-4-methyl-1-((R)-2-methyloxiran-2-yl)-1-oxopentan-2-yl)carbamate), which is an important synthetic intermediate of carfilzomib. A series of bioinspired manganese complexes bearing N4 ligands are carefully investigated in the epoxidation of enone precursor with H_2O_2 as oxidant in the presence of carboxylic acid(e.g., acetic acid).

关键词： Catalytic epoxidation Bioinspired manganese complexes Hydrogen peroxide Epoxyketone Carfilzomib

Electrochemiluminescent Detection Method for Glyphosate in Soybean on Carbon Fiber-ionic Liquid Paste Electrode

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2011年第3期29卷 581-586页

作者： Cai, Qihong Chen, Xiaoping qiu, bin Lin, Zhenyu Department of Pharmacy Medical College of Putian University Putian Fujian 351100 China Ministry of Education Key Laboratory of Analysis and Detection Technology for Food Safety Department of Chemistry Fuzhou University Fuzhou Fujian 350002 China

A carbon fiber paste electrode using ionic liquid as the binder （CFILE） was fabricated. The electrochemical characteristics of the electrode was examined in ferro-/ferricyanide solution and showed better conductivity and reversibility when compared with graphite paste-ionic liquid electrode （GPILE） and a little better than that on the carbon nanotube paste-ionic liquid electrode （CNTILE）. Glyphosate （GLY）, a pesticide, exhibited excellent catalysis to the oxidation of Ru（bpy）3^2＋ on CFILE and brought an obvious enhancement to the electrochemiluminescence （ECL） intensity of Ru（bpy）3^2＋ . Based on the catalytic ability of GLY, a simple ECL method for GLY detection had been established. Under optimum conditions, the enhanced ECL intensities were found to had linearly respond to the GLY concentration between 3.0× 10 ^-7 and 3.0× 10 ^- 5mol/L, and the detection limit （S/N=3） was 2.0× 10 ^-7 mol/L. The electrode also showed excellent sensitivity in detecting GLY-spiked soybean samples. The linear range for GLY in soybean samples was 1.0× 10 ^-6-4.0× 10 ^-5 mol/L and the detection limit was 5.0× 10 ^-7 mol/L, equal to 8.45 μg GLY in per gram of soybean. The detection limit in soybean sample was lower than the USA, EU regulation and so on. If the method is coupled with the separation technology, it can be applied to detect the GLY in the contaminated samples.

关键词： carbon fiber paste electrode ionic liquid luminescence glyphosate

Microstructure and mechanical properties of WC-(Ti,M)(C,N)-Co cemented carbides with different nitrogen contents

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2022年第10期41卷 3530-3538页

作者： Han-Jie Fan Ying Liu Jin-Wen Ye Wei-bin qiu Yu-Chong qiu School of Materials Science and Engineering Sichuan UniversityChengdu610065China

Three kinds of(Ti,M)(C_(1-x),N_(x))(M=Ta,Nb,W) quaternary solid-solution powders with various nitrogen contents were synthesized by carbothermal reductionnitridation(CRN) *** of nitrogen content on the microstructure and mechanical properties of WC-(Ti,M)(C_(1-x),N_(x))-Co cemented carbides fabricated by sinterhot isostatic pressing(HIP) were systematically investigated in this *** results show that the nitrogen content in the carbonitride raw powders strongly influences the morphology,the grain size and the compositions of the cemented *** the cemented carbides with different nitrogen contents have a similar microstructural appearance:weak core-rim structure consisting of solidsolution phase embedded in WC-Co *** is also observed that the carbonitride solid solution could somewhat reduce the WC grain growth,and the effectiveness of refining and the rim thickness are sensitively related to the nitrogen content of(Ti,M)(C_(1-x),N_(x)) solid *** addition,with an increase in the nitrogen content,mechanical properties of these hard metals are enhanced,which were discussed in terms of the constituent,the microstructure and the solution behavior of the carbonitride solid solutions.

关键词： Cemented carbides Solid-solution powders Nitrogen content Mechanical properties

Stellar spectral classification and feature evaluation based on a random forest

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2019年第8期19卷 56-62页

作者： Xiang-Ru Li Yang-Tao Lin Kai-bin qiu School of Mathematical Sciences South China Normal University

With the availability of multi-object spectrometers and the design and operation of some large scale sky surveys, the issue of how to deal with enormous quantities of spectral data efficiently and accurately is becoming more and more important. This work investigates the classification problem of stellar spectra under the assumption that there is no perfect absolute flux calibration, for example, when considering spectra from the Guo Shou Jing Telescope(the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, LAMOST). The proposed scheme consists of the following two procedures: Firstly, a spectrum is normalized based on a 17 th order polynomial fitting;secondly, a random forest(RF) is utilized to classify the stellar spectra. Experiments on four stellar spectral libraries show that the RF has good classification performance. This work also studied the spectral feature evaluation problem based on RF. The evaluation is helpful in understanding the results of the proposed stellar classification scheme and exploring its potential improvements in the future.

关键词： methods:statistical methods:data analysis virtual observatory tools

Anti-apoptotic effects of aspirin following cerebral ischemia-reperfusion injury in rats

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2008年第9期3卷 979-984页

作者： Liying qiu bin Du Ying Li Hongbin Fan Zhiyong Yang Department of Biopharmaceutical Sciences Medicine and Pharmaceutics School of Jiangnan University Wuxi 214122 Jiangsu ProvinceChina

BACKGROUND： The pharmacological effects of aspirin on apoptosis are complex. The underlying mechanisms have not been properly defined. OBJECTIVE： To observe the effect of different doses of aspirin on brain cell apoptosis following focal cerebral iscbemia-reperfusion injury （CIRI） in rats. DESING, TIME AND SETTING： A randomized, controlled, animal experiment, performed at the School of Medicine and Pharmaceutics, Jiangnan University between June and October 2006. MATERIALS： Twenty-six male, adult, Sprague Dawley rats （grade Ⅱ）, weighing 240-290 g, were obtained from Shanghai Experimental Animal Center, Chinese Academy of Sciences. Aspirin was provided by Sigma （USA）. METHODS： The rats were randomly divided into four groups： sham-operation （SO）, CIRI ＋ vehicle, CIRI ＋ aspirin （6 mg/kg）, and CIRI ＋ aspirin （60 mg/kg）. Rats in the lesion groups were intragastrically administrated saline, aspirin （6 mg/kg）, or aspirin （60 mg/kg）, respectively. MAIN OUTCOME MEASURES： The number of pyramidal neurons with normal appearance in the cerebral cortex at 24 mm from the midline; apoptotic cell death as measured by TUNEL; Bcl-2 and Bax protein localization was determined by immunohistochemistry; malondialdehyde （MDA） and super oxidation （SOD） content were determined by biochemistry method; adenosine triphosphate （ATP） content measured by capillary electrophoresis. RESULTS： Following CIRI, the following parameters were altered compared with sham-operated animals： the number of neurons with normal appearance was significantly reduced in the cerebral cortex; the number of apoptotic cells increased; Bax protein expression was enhanced; and the ratio between Bcl-2 and Bax decreased. In addition, MDA content increased significantly, whereas ATP content decreased （P 〈 0.01）. Aspirin ameliorated the loss of healthy pyramidal neurons. Both 6 and 60 mg/kg aspirin increased the ratio between Bcl-2 and Bax, with no significant difference between the treatment groups. In addition, 60 mg/kg asp

关键词： aspirin Bax Bcl-2 cerebral ischemia-reperfusion injury cell apoptosis

Esterification of Glycerol by Oleic Acid and Selective Hydrogenation of Oieic Acid Methylester Over Acid and Ru-Sn-B Supported Mesoporous AIMCM-41

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第9期12卷 823-826页

作者： qiu bin KAN J.BARRAULT Tong Hao WU Department of Chemistry Jilin UniversityChangchun 130023 Laboratoire de Catalyse CNRS URA 350-ESIP4086022 PoitiersCedexFrance

The AlMCM-41 molecular sieves with two different pore sizes are hydrothermally synthesized in the presence of surfactants with two different chain lengths. H-AlMCM-41 and Ru-Sn-B/H-AlMCM-41 which are prepared by the conventional ion-exchange and incipient wetness techniques of the AlMCM-41 show fair catalytic activity for esterification of glycerol by oleic acid and selective hydrogenation of oleic acid methylester, respectively.

关键词： AlMCM-41 Ru-Sn-B/H-AlMCM-41 oleic acid esterification hydrogenation