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排序方式: 共有114条查询结果,搜索用时 15 毫秒
1.
Molybdenum(IV) gives a red colour with ammonium thiocyanate in 5-8M hydrochloric acid medium, the Sandell sensitivity index being 0.018 ppm Mo(VI)/cm(2). Molybdenum(VI) in 4-7M hydrochloric acid medium forms a red complex with ethyl xanthate and ammonium thiocyanate and this can be extracted into acetophenone. Beer's law is obeyed over the range of 1.2-13.8 ppm, and the Sandell indices at 370 and 470 nm are 0.0016 and 0.0068 ppm/cm(2) respectively. The colour is stable for 40 hr. Most cations do not interfere. 相似文献
2.
[Cp∗IrCl2]2 catalyses the cyclization of 2-alkynylanilines into indoles. A wide variety of substrates is tolerated. A reaction pathway involving intramolecular hydroamination is proposed. 相似文献
3.
Rangarajulu Senthil Kumaran Yong-Keun Choi Hyung Joo Kim Kwang Jin Kim 《Applied biochemistry and biotechnology》2014,173(3):731-740
The objective of this study was to assess the cytotoxicity of water-dispersible CuO nanoparticles by quantifying the reactive oxygen species (ROS)-related genes (glutathione S-transferase (GST) and catalase) using real-time polymerase chain reaction (RT-PCR). Monodisperse CuO nanoparticles of 14 nm in size were used. Cytotoxicity of CuO nanoparticles was evaluated under in vitro condition at different concentrations (10, 50, and 100 μg/ml) and incubation times (12, 24, and 48 h) with human cancer cell lines (breast cancer epithelial cells). The genetic level cytotoxic screening produced consistent results showing that GST and catalase ROS gene expression was maximized in 24 h incubation at 100 μg/ml concentration of CuO nanoparticles. However, the cytotoxicity of water-dispersible CuO nanoparticle was not significant compared with control experiments, demonstrating its high potential in the application of nanomedicines for a diagnostic and therapeutic tool. 相似文献
4.
An efficient solvent-free method for the preparation of esters from various aromatic and aliphatic acids with primary, secondary, and tertiary alcohols using a heterogeneous phosphine reagent, silphos [PCl3-n(SiO2)n], in good yields is reported. 相似文献
5.
Shutao Wang Kan Liu Jian Liu Zeta T.‐F. Yu Xiaowen Xu Libo Zhao Tom Lee Eun Kyung Lee Jean Reiss Yi‐Kuen Lee Leland W. K. Chung Jiaoti Huang Matthew Rettig David Seligson Kumaran N. Duraiswamy Clifton K.‐F. Shen Hsian‐Rong Tseng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2011,123(13):2909-2909
6.
The time evolution in the temperature field resulting from the sudden introduction of a heat source into the already fully established steady MHD flow of an electrically conducting fluid past a linearly stretching isothermal surface is considered. The problem is shown to be fully described by two dimensionless parameters, a modified magnetic field strength ?? and a heat source strength Q. Numerical solutions of the initial-value problem show that there is a critical value Q c of the parameter Q, dependent on ??, such that, for Q<Q c , the solution approaches a steady state at large times and, for Q>Q c , the solutions grows exponentially large as time increases. This growth rate is determined through an eigenvalue problem which also determines the critical value Q c . The limits of Q c for both small and large values of ?? are discussed. 相似文献
7.
The angular variations of the five-fold differential cross section obtained by using different wave functions of helium are
compared with experimental data. It is found that in the coplanar geometry two kinematical arrangements, (i) equal energy
sharing between the two ejected electrons with one of them ejected along the momentum transfer direction and the other along
varying direction and (ii) the Bethe ridge condition with fixed sum of ejected electron energies and varying angle between
them, are very sensitive to e-e correlations contained in the target wave function. This comparison has been used to show
that open-shell class of wave functions better incorporate e-e correlations than the closed-shell class. 相似文献
8.
9.
A facile one-pot sequential three-component route to 2,4-diaminothiazoles is reported. The new approach employs the mildest reaction conditions and commercially available reagents to generate diverse 2-alkyl/arylamino-4-amino-5-aroyl/heteroylthiazoles in short reaction times, good yield, and purity. 相似文献
10.
R. Kumaran T. Varalakshmi E. J. Padma Malar P. Ramamurthy 《Journal of fluorescence》2010,20(5):993-1002
Photophysical studies of photoinduced electron transfer (PET) and non-PET based acridinedione dyes with guanidine hydrochloride
(GuHCl) were carried out in water and methanol. Addition of GuHCl to photoinduced electron transfer (PET) based acridinedione
dye (ADR 1) results in a fluorescence enhancement, whereas a non-PET based dye (ADR 2) shows no significant change in the
fluorescence intensity and lifetime. Addition of GuHCl to ADR 1 dye in methanol results in single exponential decay behaviour,
on the contrary a biexponential decay pattern was observed on the addition of GuHCl in water. Absorption and emission spectral
studies of ADR 1 dye interaction with GuHCl reveals that the dye molecule is not in the protonated form in aqueous GuHCl solution,
and the dye is confined to two distinguishable microenvironment in the aqueous phase. A large variation in the microenvironment
around the dye molecule is created on the addition of GuHCl and this was ascertained by time-resolved area normalized emission
spectroscopy (TRANES) and time-resolved emission spectroscopy (TRES). The dye molecule prefers to reside in the hydrophobic
microenvironment, rather in the hydrophilic aqueous phase is well emphasized by time-resolved fluorescence lifetime studies.
The mechanism of fluorescence enhancement of ADR 1 dye by GuHCl is attributed to the suppression of the PET process occuring
through space. 相似文献