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Mingjuan Li Liqun Sun Kai Sun Shihua Yu Rongshun Wang Haiming Xie 《Journal of Solid State Electrochemistry》2012,16(11):3581-3586
Nanoscale LiFePO4/C particles are synthesized using a combination of electrospinning and annealing. The important advantages of electrospinning technique are the production of separated nanofiber precursor, enabling the precursor particles arrangement to be changed, impeding the growth and agglomeration of the LiFePO4 particles during the heat treatment, and contributing to the formation of nanosized LiFePO4 particles. In this study, polyvinylpyrrolidone (PVP) is used as the fiber-forming agent in the electrospinning method, and also provides a reducing agent and carbon source. In situ carbon-coated LiFePO4 particles are obtained by the pyrolysis of PVP during the thermal treatment. The LiFePO4 particles are coated with and connected by interlaced carbons, and are uniformly distributed in the size range 50–80?nm. It is found that the as-prepared nanoscale LiFePO4/C composite has a desirable electrochemical performance. It has discharge capacities of 163.5?mA?h g?1 and 110.7?mA?h g?1 at rates of 0.1?C and 10?C, respectively. In addition, this cathode has excellent cyclability with a capacity loss of less than 3?% at 0.1?C and 5?% at 5?C after 500 cycles. An effective synthesis and processing method is presented for obtaining nanosized LiFePO4 with high electrochemical performance. 相似文献
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A novel poly(ether sulfone) with oligoaniline pendants(PESOP) was prepared by K2CO3-mediated nucleophilic polycondensation and characterized with Fourier-transform infrared spectrometry(FTIR), 1H nuclear magnetic resonance(1H NMR) and gel permeation chromatography(GPC). The cyclic voltammetry(CV) curve of PESOP reveals the reversible electroactivity. In the electrochromism study, PESOP film exhibited good electrochromic properties with a high contrast value, moderate switching time and acceptable coloration efficiency. After running 1000 cycles, the PESOP/indium-tin oxide(ITO) electrochromic device remained unchanged except for the drifting of base line, which certified its good electro-photo stability of the fabricated electrochromic device. Moreover, the polarization technique and electrochemical impedance spectroscopy(EIS) were used to study the anticorrosion performance of PESOP coatings on the cold rolled steel(CRS) in a 5%(mass fraction) NaCl solution. All the results indicate that the obtained PESOP is a competitive candidate as anticorrosion material. 相似文献
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Fuzzy综合评判在评价教师教学质量工作中的应用 总被引:1,自引:0,他引:1
本文应用Fuzzy综合评判方法及教育测量学知识综合评价教师的教学质量.此法较其它评价方法更客观、细腻、可靠,对教学管理工作具有参考价值. 相似文献
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Cover Picture: Autocrine‐Based Selection of Drugs That Target Ion Channels from Combinatorial Venom Peptide Libraries (Angew. Chem. Int. Ed. 32/2016) 下载免费PDF全文
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Mingjuan Han Ying Chu Lili Li 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,324(1-3):143-148
The calcium silicate systems were prepared by sol–gel methods—varying the synthesis conditions (precursor solutions, chemical compositions, catalysts, temperature and time of aging and heat treatment). The precursors of sol–gel procedures were calcium nitrate and tetraetoxysilane. Acetic acid, water, ammonia and nitric acid were applied as catalysts. The atomic and supramolecular structures of calcium silicate products have been varied from amorphous to crystalline phases depending strongly on the preparation conditions. The structures were investigated in atomic range with Fourier transform infrared (FTIR), X-ray diffraction (XRD) and in supramolecular ranges with small angle X-ray scattering (SAXS), ultra small angel X-ray scattering (USAXS) measurements. The mechanical properties could be most efficiently improved by heat treatments (min. 600 °C) and a post-treatment with tetraetoxysilane (TEOS). The mechanical strength of bulk biomaterials has been controlled by Brinell hardness test. 相似文献
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The completely N(1)-selective Pd-catalyzed arylation of unsymmetric imidazoles with aryl halides and triflates is described. This study showed that imidazoles have a strong inhibitory effect on the in situ formation of the catalytically active Pd(0)-ligand complex. The efficacy of the N-arylation reaction was improved drastically by the use of a preactivated solution of Pd(2)(dba)(3) and L1. From these findings, it is clear that while imidazoles can prevent binding of L1 to Pd, once the ligand is bound to the metal, these heterocycles do not displace it. The utility of the present catalytic system was demonstrated by the regioselective synthesis of the clinically important tyrosine kinase inhibitor nilotinib. 相似文献
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紫外可见分光光度法测定不同产地龙牙百合中皂苷含量 总被引:2,自引:0,他引:2
为建立龙牙百合总皂苷的测定方法,并确定不同产地龙牙百合中皂苷的含量,以便控制龙牙百合药材的质量,采用香草醛-高氯酸显色,在535 nm处,利用紫外可见分光光度法测定了10个批次的龙牙百合中总皂苷的含量.结果表明,10个不同产地龙牙百合中皂苷的含量,分别是:8.39%、8.11%、8.24%、7.62%、7.38%、9.... 相似文献