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31.
Synthesis,Thermal Behavior,and Dehydrogenation Kinetics Study of Lithiated Ethylenediamine 下载免费PDF全文
Juner Chen Dr. Guotao Wu Prof. Zhitao Xiong Dr. Hui Wu Dr. Yong Shen Chua Dr. Wei Zhou Bin Liu Xiaohua Ju Prof. Ping Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13636-13643
The lithiation of ethylenediamine by LiH is a stepwise process to form the partially lithiated intermediates LiN(H)CH2CH2NH2 and [LiN(H)CH2CH2NH2][LiN(H)CH2CH2N(H)Li]2 prior to the formation of dilithiated ethylenediamine LiN(H)CH2CH2N(H)Li. A reversible phase transformation between the partial and dilithiated species was observed. One dimensional {LinNn} ladders and three‐dimensional network structures were found in the crystal structures of LiN(H)CH2CH2NH2 and LiN(H)CH2CH2N(H)Li, respectively. LiN(H)CH2CH2N(H)Li undergoes dehydrogenation with an activation energy of 181±8 kJ mol?1, whereas the partially lithiated ethylenediamine compounds were polymerized and released ammonia at elevated temperatures. The dynamical dehydrogenation mechanism of the dilithiated ethylenediamine compounds was investigated by using the Johnson‐Mehl‐Avrami equation. 相似文献
32.
Back Cover: Chemical Preparation of Graphene Materials Results in Extensive Unintentional Doping with Heteroatoms and Metals (Chem. Eur. J. 48/2014) 下载免费PDF全文
33.
Wei Jin Wei-Yu Wang Yu-Lian Zhang Yong-Jian Yang Qing-Cui Chu Jian-Nong Ye 《中国化学快报》2013,24(7):636-638
A sensitive method for simultaneous determination of six phenolic whitening agents,including arbutin, phenol,resorcinol,hydroquinone,kojic acid,and salicylic acid in cosmetics has been developed using micellar electrokinetic capillary chromatography with amperometric detection(MECC-AD).Effects of several factors,such as the pH value and concentration of running buffer,potential applied to the working electrode,separation voltage,and injection time were investigated to obtain optimum conditions for separation and detection.With a 75 cm long fused-silica capillary tube,well-defined separation of six phenolic compounds was achieved in 10mmol/L SDS/40 mmol/L H3BO3-Na2B4O7 running buffer(pH 9.0).Good linear relationship was obtained for each analyte over three orders of magnitude with correlation coefficients(r2) between 0.9985 and 0.9994,and the detection limit(S/N=3) ranged from 0.04μg/mL to 0.45μg/mL The proposed method has been successfully applied for the determination of phenolic whitening agents in real cosmetic samples with satisfactory results,providing an alternative monitoring method for cosmetics safety regulation. 相似文献
34.
Inside Cover: Rational Design of Carboxyl Groups Perpendicularly Attached to a Graphene Sheet: A Platform for Enhanced Biosensing Applications (Chem. Eur. J. 1/2014) 下载免费PDF全文
35.
Dr. Krystle C. H. Chua Dr. Markus Pietsch Xiaozhou Zhang Stephanie Hautmann Hon Y. Chan Dr. John B. Bruning Prof. Dr. Michael Gütschow Prof. Dr. Andrew D. Abell 《Angewandte Chemie (International ed. in English)》2014,53(30):7828-7831
There is a real need for simple structures that define a β‐strand conformation, a secondary structure that is central to peptide–protein interactions. For example, protease substrates and inhibitors almost universally adopt this geometry on active site binding. A planar pyrrole is used to replace two amino acids of a peptide backbone to generate a simple macrocycle that retains the required geometry for active site binding. The resulting β‐strand templates have reduced peptide character and provide potent protease inhibitors with the attachment of an appropriate amino aldehyde to the C‐terminus. Picomolar inhibitors of cathepsin L and S are reported and the mode of binding of one example to the model protease chymotrypsin is defined by X‐ray crystallography. 相似文献
36.
The NO catalytic direct decomposition was studied over La2CuO4 nanofibers, which were synthesized by using single walled carbon nanotubes (CNTs) as templates under hydrothermal condition. The composition and BET specific surface area of the La2CuO4 nanofiber were La2Cu0.882+Cu0.12+O3.94 and 105.0 m2/g, respectively. 100% NO conversion (turnover frequency-(TOF): 0.17 gNO/gcatalyst s) was obtained over such nanofiber catalyst at temperatures above 300 °C with the products being only N2 and O2. In 60 h on stream testing, either at 300 °C or at 800 °C, the nanofiber catalyst still showed high NO conversion efficiency (at 300 °C, 98%, TOF: 0.17 gNO/gcatalyst s; at 800 °C, 96%, TOF: 0.16 gNO/gcatalyst s). The O2 and NO temperature programmed desorption (TPD) results indicated that the desorption of oxygen over the nanofibers occurred at 80-190 and 720-900 °C; while NO desorption happened at temperatures of 210-330 °C. NO and O2 did not competitively adsorb on the nanofiber catalyst. For outstanding the advantage of the nanostate catalyst, the usual La2CuO4 bulk powder was also prepared and studied for comparison. 相似文献
37.
Chua Hong Tan Kok N. Cheung Montgomery W. L. 《Applied biochemistry and biotechnology》1996,57(1):851-856
Applied Biochemistry and Biotechnology - Bulking and foaming in activated sludge have been associated with filamentous overgrowth. FilamentousNocardia amarae and nonfilamentousPseudomonas... 相似文献
38.
Lin Ke Shuang Fang Lim Soo Jin Chua 《Journal of Polymer Science.Polymer Physics》2001,39(14):1697-1703
Dark spot growth rate tracing experiments performed on an organic light‐emitting device show that moisture entering into the device is relatively properly fitted by Fick's diffusion equation in the substrate/indium tin oxide (ITO)/hole transport layer (HTL)/silver (Ag) structure. It is believed that the moisture is dissolved into the polymer layer, which results in a decrease in the diffusion coefficient in the device with the substrate/ITO/HTL/electroluminescent (EL) polymer/Ag structure. The diffusion and chemical reaction occurring in the cathode layer further decreases the diffusion coefficient in the device with the substrate/ITO/HTL/EL polymer/calcium/Ag structure. Useful parameters, such as diffusion and solubility constants, describing possible mechanisms happening during dark spot growth on organic light‐emitting diode devices are extracted. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1697–1703, 2001 相似文献
39.
40.
We compare two methods of calibrating the yaw response of hot-wire probes: (i) the assumption that an effective angle, independent
of the flow speed, can be deduced; (ii) the more general approach of determining the yaw response at a number of different
speeds. The first, simpler, approach is shown to give surprisingly reasonable results for the usual turbulence statistics,
even in high turbulence intensity flows. Some differences in the distribution of the inclination of the instantaneous velocity
vector are observed. There is no advantage in using thek
2 factor to allow for longitudinal cooling. 相似文献