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831.
A wide range of multisubstituted 1-indanones of potential pharmaceutical use were synthesized in a one-pot fashion in moderate to excellent yields via palladium catalysis in ethylene glycol. The Heck reaction first installs an enol functionality on the aromatic ring; this is followed by an ethylene glycol promoted aldol-type annulation with a neighboring carbonyl group, resulting in the formation of various 1-indanones. 相似文献
832.
A one-pot, two-step catalytic protocol has been developed. A regioselective Heck coupling between aryl bromides and allyl alcohol leads to the generation of arylated allyl alcohols that in situ isomerize to give aldehydes, which then undergo an acylation reaction with a second aryl bromide. A variety of aryl bromides can be employed in both the initial Heck reaction and the acylation, providing easy access to a wide variety of substituted dihydrochalcones. 相似文献
833.
A method based on the combination of solid-phase extraction (SPE) with gas chromatography-mass spectrometry (GC/MS) for detailed chemical fingerprinting of biodiesel/petrodiesel blends was developed in the present study. Forensic identification, commonly referred to as chemical fingerprinting, is based on the relative distributions of individual aliphatic hydrocarbons, aromatic hydrocarbons, fatty acid alkyl esters, and free sterols. Fractionation of fuel samples is optimized for the separation of fatty acid esters and free sterols from petroleum hydrocarbons into four fractions: aliphatic, aromatic, fatty acid ester, and polar components. The final recoveries of aliphatic and aromatic hydrocarbons were determined to be in the range of 65-103%, 73-105% for FAMEs, and 78-103% for free sterols in the polar fraction. Excellent separation with negligible crossover of components with different polarities between fractions was observed. Quantitative analysis of blend levels and individual chemical distribution were achieved. The method has great potential for the identification of biodiesel in diesel fuel blends and could form the basis of a method for characterization of biodiesel-contaminated environmental samples. 相似文献
834.
Wu H Hu L Carney T Ruan Z Kong D Yu Z Yao Y Cha JJ Zhu J Fan S Cui Y 《Journal of the American Chemical Society》2011,133(1):27-29
Tin-doped indium oxide (ITO) has found widespread use in solar cells, displays, and touch screens as a transparent electrode; however, two major problems with ITO remain: high reflectivity (up to 10%) and insufficient flexibility. Together, these problems severely limit the applications of ITO films for future optoelectronic devices. In this communication, we report the fabrication of ITO nanofiber network transparent electrodes. The nanofiber networks show optical reflectivity as low as 5% and high flexibility; the nanofiber networks can be bent to a radius of 2 mm with negligible changes in the sheet resistance. 相似文献
835.
Dujuan Li Yangyang Feng Ling Zhou Zunzhong Ye Jianping Wang Yibin Ying Chuanmin Ruan Ronghui Wang Yanbin Li 《Analytica chimica acta》2011,(1):9450
A label-free capacitive immunosensor based on quartz crystal Au electrode was developed for rapid and sensitive detection of Escherichia coli O157:H7. The immunosensor was fabricated by immobilizing affinity-purified anti-E. coli O157:H7 antibodies onto self-assembled monolayers (SAMs) of 3-mercaptopropionic acid (MPA) on the surface of a quartz crystal Au electrode. Bacteria suspended in solution became attached to the immobilized antibodies when the immunosensor was tested in liquid samples. The change in capacitance caused by the bacteria was directly measured by an electrochemical detector. An equivalent circuit was introduced to simulate the capacitive immunosensor. The immunosensor was evaluated for E. coli O157:H7 detection in pure culture and inoculated food samples. The experimental results indicated that the capacitance change was linearly correlated with the cell concentration of E. coli O157:H7. The immunosensor was able to discriminate between cellular concentrations of 102–105 cfu mL−1 and has applications in detecting pathogens in food samples. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were also employed to characterize the stepwise assembly of the immunosensor. 相似文献
836.
Three stress-tolerant phosphate-solubilizing fungal strains identified as Aspergillus niger, Aspergillus japonicus, and Penicillium simplicissimum were isolated from wheat rhizospheric soil. The strains demonstrated different capabilities of phosphate solubilization in National Botanical Research Institute's phosphate medium containing rock phosphate (RP) as sole phosphorus (P) source, and the solubilization of RP by P. simplicissimum was the most effective among these strains, followed by A. niger and A. japonicus. All the strains exhibited high levels of stress tolerance like 10~45°C temperature, 4~11 pH, 0~3.5% NaCl, and 0~35% PEG 10000. The strains also differed in their abilities to survive and release soluble P from RP under different stresses. A. niger showed significantly higher tolerance to temperature and pH over the other two strains. Higher amount of spores and content of soluble P in the medium were observed in the presence of 3.5% NaCl with P. simplicissimum, followed by A. niger and A. japonicus. P. simplicissimum could not solubilize RP in the presence of 35% PEG 10000, which exhibited the lowest tolerance to desiccation stress among the three strains. 相似文献
837.
Zhuo Ping Ruan 《数学学报(英文版)》2011,27(10):1967-1978
We apply discrete Littlewood-Paley-Stein theory, developed by Han and Lu, to establish Calderón-Zygmund decompositions and
interpolation theorems on weighted Hardy spaces H
w
p
for ω ∈ A
∞ in both the one-parameter and two-parameter cases. 相似文献
838.
A new numerical method, which is based on the coupling between variational multiscale method and meshfree methods, is developed for the water wave problems, in which the free surface capturing technique is used to capture the position of the free surface. The proposed method takes full advantage of meshfree methods, therefore, no mesh generation and mesh reconstruction are involved. Meanwhile, due to that the proposed method belongs to meshfree methods, thus it is suitable for the highly deformed free surface flow problems. Finally, two water wave problems are solved and the results have also been analyzed. The numerical results show that the proposed method can indeed obtain accurate numerical results for the water wave problems, which does not refer to the choice of a proper stabilization parameter. 相似文献
839.
840.
R.A. KhanA.S. Bhatti Ruan Kaibin 《Journal of magnetism and magnetic materials》2011,323(22):2841-2845
In this paper, we report investigation of room temperature (RT) ferromagnetism in In2O3 (InO) thin films doped with carbon prepared by the co-sputtering method. InO thin films both undoped and C doped with varied thicknesses in the range of 45 to 80 nm were synthesized on Si substrates with varied C concentrations. The carbon concentration was varied from 1.6 to 9.3 at%. The undoped InO films showed no trace of ferromagnetism. Carbon doped films (InO:C) exhibited ferromagnetism at RT, which was of the orders of 10−5 emu and varied strongly with C concentrations. It is observed that the magnetization reached a maximum value of 5.7 emu/cm3 at 4 at% C. Annealing of the InO:C films in an oxygen environment resulted in a decrease in the magnetization, indicating the crucial role of oxygen vacancies in the films. It is concluded that the oxygen vacancies were important and compete with C substitution for the RT ferromagnetism. 相似文献