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991.
萃取—火焰原子吸收法测定骨骼中的微量元素Cu,Zn,Cd和Fe 总被引:9,自引:0,他引:9
本文研究了以邻菲罗啉为金属螯合剂,高氯酸钠为配体,在一定酸度下用1,2-二氯乙烷萃取-火焰原子吸收法测定动物骨骼中微量Cu,Zn,Cd和Fe的条件,并确定了测定方法,方法简单,准确,可靠,元素的检测限分别为:Cu:0.038μg/ml,Zn:0.0042μg/ml,Cd:0.0019μg/ml,Fe:0.02μg/ml,回收率在92.8%~105%之间。 相似文献
992.
Li L Wong YS Chen T Fan C Zheng W 《Dalton transactions (Cambridge, England : 2003)》2012,41(4):1138-1141
A series of ruthenium complexes containing bis-benzimidazole derivatives have been synthesized and identified as able to target mitochondria and induce caspase-dependent apoptosis in cancer cells through superoxide overproduction. 相似文献
993.
Peng Xiong Fan Xu Xiang‐Yang Qian Yared Yohannes Dr. Jinshuai Song Prof. Dr. Xin Lu Prof. Dr. Hai‐Chao Xu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4379-4383
A copper‐catalyzed oxidative amination of unactivated internal alkenes has been developed. The Wacker‐type oxidative alkene amination reaction is traditionally catalyzed by a palladium through a mechanism involving aminopalladation and β‐hydride elimination. Replacing the precious and scarce palladium with a cheap and abundant copper for this transformation has been challenging because of the difficulty associated with the aminocupration of internal alkenes. The combination of a simple copper salt, without additional ligand, as the catalyst and Dess–Martin periodinane as the oxidant, promotes efficiently the oxidative amination of allylic carbamates and ureas bearing di‐ and trisubstituted alkenes leading to oxazolidinones and imidazolidinones. Preliminary mechanistic studies suggested a hybrid radical–organometallic mechanism involving an amidyl radical cyclization to form the key C?N bond. 相似文献
994.
Min‐Min Fan Zhi‐Jun Yu Hai‐Ya Luo Sheng Zhang Bang‐jing Li 《Macromolecular rapid communications》2009,30(11):897-903
A novel supramolecular network has been prepared based on the formation of inclusion complexes between γ‐cyclodextrin and poly(ethylene glycol), in which the PEG chains are interlocked by γ‐CD rings. This PEG/γ‐CD network exhibits good shape memory behavior because of the crosslinked structure. The crosslinked PEG/γ‐CD inclusion complexes and PEG crystallites account for the fixing phase and reversible phase, respectively. The characteristics of the materials have been investigated by 1H NMR spectroscopy, XRD, DSC, DMA, viscosity tests, and swelling measurements.
995.
An efficient synthetic method for the formation of 2,3-dihydro-1H-inden-1-one derivatives through a Ni-catalyzed intramolecular hydroacylation of 2-(prop-2-ynyl)benzaldehydes has been developed. Examination of various nickel and other transition metal catalysts and phosphine ligands showed that the use of Ni(COD)2 catalyst combined with P(i-Pr)3 ligand was the best choice to the success of the present intramolecular hydroacylation. A wide range of functional groups were tolerated, affording the corresponding substituted α-lidene-2,3-dihydro-1H-inden-1-ones in good to high yields with a sole E-selectivity under present reaction conditions. 相似文献
996.
We study an initial boundary value problem for the equations of plane magnetohydrodynamic compressible flows, and prove that
as the shear viscosity goes to zero, global weak solutions converge to a solution of the original equations with zero shear
viscosity. As a by-product, this paper improves the related results obtained by Frid and Shelukhin for the case when the magnetic
effect is neglected.
Supported by NSFC (Grant No. 10301014, 10225105) and the National Basic Research Program (Grant No. 2005CB321700) of China. 相似文献
997.
Weidong Gao Meiqiong Zhan Shuhai Fan Janda Shao Zheng-Xiu Fan 《Applied Surface Science》2005,250(1-4):195-202
The laser-induced damage (LID) behavior of narrow-band interference filters was investigated with a Nd:YAG laser at 1064 nm under single-pulse mode and free-running mode. The absorption measurement of such coatings was performed with surface thermal lensing (STL) technique. The damage morphologies under the two different laser modes were also studied in detail. It was found that all the filters exhibited a pass-band-center-dependent absorption and laser-induced damage threshold (LIDT) behavior, but the damage morphologies were diverse. The explanation was given with the analysis of the electric field distribution and the operational behavior of the irradiation laser. 相似文献
998.
999.
A highly parallelizable means of positioning or sorting particles in a size-selective manner into arrays is demonstrated based on the placement of particle suspensions on surfaces of patterned wettability and the subsequent evaporation of the suspending solvent. The method relies on creating lyophilic features of dimensions similar to or greater than those of the particles to be arrayed and smaller than those of the particles to be excluded. As the contact line recedes, it fills lyophilic features, creating discrete fluid elements that mimic the underlying lyophilic pattern. The fluid elements have aspect ratios dictated by the contact angle. By adjusting the size of the lyophilic features, the heights of the fluid elements can be adjusted to sequester or exclude particles based on their diameter. The principal interest of this work is its broad applicability. No prior understanding of the particle properties is needed except for the size of the particle and its ability to be suspended in a solvent. 相似文献
1000.
Shijie Liu Jianyong Ma Zicai Shen Yunxia Jin Zhengxiu Fan 《Applied Surface Science》2007,253(7):3642-3648
Thin-film design used to fabricate multi-layer dielectric (MLD) gratings should provide high transmittance during holography exposure, high reflectance at use wavelength and sufficient manufacturing latitude of the grating design making the MLD grating achieve both high diffraction efficiency and low electric field enhancement. Based on a (HLL)9H design comprising of quarter-waves of high-index material and half-waves of low-index material, we obtain an optimum MLD coating meeting these requirements by inserting a matching layer being half a quarter-wave of Al2O3 between the initial design and an optimized HfO2 top layer. The optimized MLD coatings exhibits a low reflectance of 0.017% under photoresist at the exposure angle of 17.8° for 413 nm light and a high reflectance of 99.61% under air at the use angle of 51.2° for 1053 nm light. Numerical calculation of intensity distribution in the photoresist coated on the MLD film during exposure shows that standing-wave patterns are greatly minimized and thus simulation profile of photoresist gratings after development demonstrates smoother shapes with lower roughness. Furthermore, a MLD gratings with grooves etched into the top layer of this MLD coating provides a high diffraction efficiency of 99.5% and a low electric field enhancement ratio of 1.53. This thin-film design shows perfect performances and can be easily fabricated by e-beam evaporation. 相似文献