摘要:

AbstractBy the method of Density Functional Theory, at B3LYP/6–311G** level, works are done to optimize the charge distribution of nine kinds of aromatic groups. Meanwhile, the activation hardness is introduced and used to check the presented calculations' validity. Based on these studies, the orientation of electrophilic aromatic substitution is discussed. Experimental results show that the nitrification activity described with NBO net charge has a relationship with the nitrification strength, and it is an excellent index for predicting orientation effect

ISSN:0009-4536    

DOI:10.1002/jccs.201000134

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractIn this work, a highly sensitive and selective optical probe for cysteine was developed using unmodified gold nanoparticles. Quick visual detection depended on the distance‐dependent optical properties of gold nanoparticles, the self‐assembly of cysteine on the surface of gold nanoparticles, and the chelation in the presence of lead ions. The form of complex could rapidly induced the aggregation of gold nanoparticles, thereby resulting in red‐to‐blue (or purple) color change. The concentration of cysteine was determined with a limit of detection (LOD) lower than 1 × 10−7M by the naked eye and could further be monitored by a UV‐vis spectrometer easily. The highest selectivity was proved in comparison with other seventeen amino acids and the relative mechanism was detailedly investigated by the addition of ethylenediaminetetraac

ISSN:0009-4536    

DOI:10.1002/jccs.201000135

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractNanocrystalline hard magnetic SrFe12O19(Sr‐M) particles incorporated with high dielectric constant SrTiO3(STO, up to 15 mol%), which are being investigated as potential materials for microwave absorption, were synthesized simultaneously in one step through a combustion reaction using nitrates and glycine as raw materials. The desired products simply composed of Sr‐M and STO can be obtained after calcination of the as‐burned nanoparticles products at 900 °C for 1 h. The effects of the STO content on the relative complex permittivity (ϵr= ϵ′ −jϵ″), permeability (μr= μ′ −jμ″) and the behavior of microwave absorption in the frequency range of 1 MHz − 1.8 GHz have been investigated. Adding more STO to Sr‐M was demonstrated not only to improve ϵrbut also to modify μr. In addition, it was found that the sintered specimens showed a characteristic of broad‐band absorption, and their absorbing efficiencies were enha

ISSN:0009-4536    

DOI:10.1002/jccs.201000136

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractGenetic algorithm and multiple linear regression (GA‐MLR), partial least square (GA‐PLS), kernel PLS (GA‐KPLS) and Levenberg‐Marquardt artificial neural network (L‐M ANN) technique were used to investigate the correlation between retention index (RI) and descriptors for diverse compounds in essential oils. The correlation coefficient cross validation (Q2) between experimental and predicted retention index for training and test sets by GA‐MLR, GA‐PLS, GA‐KPLS and L‐M ANN was 0.948, 0.924, 0.958 and 0.980 (for training set), 0.917, 0.890, 0.915 and 0.954 (for test set), respectively. The L‐M ANN model with the final optimum network architecture of [5‐2‐1] gave a significantly better performance than the other models. This indicates that L‐M ANN can be used as an alternative modeling tool for quantitative structure‐property/retention relat

ISSN:0009-4536    

DOI:10.1002/jccs.201000137

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractTwo novel metal‐organic coordination complexes of copper(II) and silver(I) with 1,3,4‐thiadiazole‐based ligands HL1[N‐(5‐methyl‐1,3,4‐thiadiazol‐2‐yl)‐4‐pyridinecarboxamide] and H2L2[2,5‐dipropanoylamino‐1,3,4‐thiadiazole] have been synthesized in diffusion conditions and characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction analysis. The X‐ray crystal structural determinations show that complex [Cu2(L1)2(BF4)(OH)]∞(1) is a three‐dimensional (3‐D) framework containing channels along thecaxis, and the channels' inner surface decorated by S atom. Complex [Ag2(H2L2)2(HL2)(PF6)]∞(2) shows a one‐dimensional chain comprising two five‐coordinated silver centers which form dinuclear structure units. The AgṁṁṁAg weak interactions were observed between the

ISSN:0009-4536    

DOI:10.1002/jccs.201000138

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractSilica bondedN‐propyl sulfamic acid (SBNPSA) is employed as a solid acid catalyst for the synthesis of 1,8‐dioxo‐decahydroacridines and 1,8‐dioxo‐octahydroxanthenes in high yields and short reaction times in ethanol under reflux conditions. Also, this solid acid catalyzed the reaction of 1,2‐diamino compounds with 1,2‐dicarbonyl compounds for the synthesis of quinoxaline derivatives at room temperature. The catalyst could be recycled and reused several times without any loss

ISSN:0009-4536    

DOI:10.1002/jccs.201000139

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractA variety of prefractionation methods for proteome analysis had been developed, but some of these had defects such as requirements sophisticated apparatus, expensive reagents, too long experimental time or complicated operation. In this work, a simple, rapid and low‐cost prefractionation method for proteome analysis was developed based on an aqueous two‐phase system (ATPS), which used simple and inexpensive components in place of the polymers, could pre‐separate proteomic proteins into multigroups by one‐step extraction according proteins' difference in solubility. The ATPS consisted of isopropanol, ammonium sulfate and water. The highlight attractiveness of this method included simplicity, rapidity, low cost and the ability of concentrating target proteins. Attractiveness of this method also included biocompability, amenability to linear scale‐up, potential for continuous operation, and being easy or no need for separating the target proteins from phase‐forming reagents before gel electrophoresis analysis. It was the first time that the ATPS composed of isopropanol, ammonium sulfate and water was used in studying the prefractionation method for proteome analysis. Thus, this method had great significance in proteome analysis and

ISSN:0009-4536    

DOI:10.1002/jccs.201000140

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractMolecular dynamics simulation was carried out to study the structure properties of α‐Zirconium Phosphate (α‐ZrP) loaded with n‐butylamine molecules. Two minimum‐energy configurations of α‐ZrP with interlayer distances 12.7 and 17.0 Å were found from the simulation. The structure properties of n‐butylmine, α‐ZrP and also interaction between n‐butylamine and α‐ZrP were analyzed. The different phase behavior was found due to the different strength of interaction between NH2in n‐butyla

ISSN:0009-4536    

DOI:10.1002/jccs.201000141

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractThis research successfully produces high quality cobalt titanate (CoTiO3) thin films, a high‐k material for gate dielectrics, on SiO2/Si(100) substrates via a spin‐coating method with a sol‐like precursor solution. This study prepares the precursor solution by reactions of cobalt acetate and titanium isopropoxide in 2‐methoxyethanol. The current work obtains CoTiO3thin films after spin coating followed by post‐treatment with air under 550∼650 °C. A scanning electron microscope, determines film thickness and morphology and X‐ray diffraction identifies material structures. This study uses X‐ray photoelectron spectroscopy to analyze both elemental compositions and chemical bonding characters of the thin films. This work also investigates r

ISSN:0009-4536    

DOI:10.1002/jccs.201000142

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractIn the present study, a new sensitive and simple kinetic‐spectrophotometric method for the determination of the insecticide dimethoate[O,O‐dimethyl‐S‐(N‐methyl‐carbomoylmethyl)‐phosphoro‐dithioate] is developed. The method is based on the inhibited effect of dimethoate on the oxidation of sulphanilic acid (SA) by potassium periodate in acetate buffer in presence Fe(III) ion and 1,10‐phenantroline. Dimethoate was determined with linear calibration graph in the interval from 28.10 to 196.70 ng/mL. The optimized conditions yielded a theoretical detection limit of 21.64 ng/mL based on the 3Sbcriterion. The RSD is 4.85‐1.2% for the concentration interval of dimethoate 28.10‐196.70 ng/mL. The reaction was followed spectrophotometrically at 368 nm. The kinetic parameters of the reaction are reported, and the rate equations are suggested. The developed procedure was successfully applied to the rapid determination of dimethoate in spiked milk and water samples. Liquid‐liquid extraction and solid‐phase extraction (SPE) was used for extraction of dimethoate from milk and water samples with Chromabond® (Macherey‐Nagel) C18 cartridges. The HPLC method was used like an comparative method to verify the results. The results obtained by two different m

ISSN:0009-4536    

DOI:10.1002/jccs.201000143

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY