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211.
We derive some strong type and weak type weighted norm estimates which relate the commutators of potential integral operators to the corresponding maximal operators in the context of spaces of homogeneous type. 相似文献
212.
We derive the two-weight inequalities for the commutators of potential integral operators in the context of spaces of homogeneous
type. The conditions required of the weights involve the Orlicz bumps. As a consequence, we obtain the norm estimates for
these commutators for arbitrary weights.
Supported by the National Natural Science Foundation of China (Nos. 10771049, 60773174) and the Natural Science Foundation
of Hebei Province (08M001). 相似文献
213.
Di-t-butylimidodicarbonates can be chemoselectively and efficiently deprotected to the corresponding mono-BOC-protected amines in high yields using a catalytic amount of bismuth(III) bromide in acetonitrile at room temperature. This method is mild and compatible with the presence of a wide range of functional and other protecting groups in the substrates, such as TBDMS, MOM and mono-BOC or Cbz-protected amines, etc. The method has advantages of ease of operation and use of nontoxic and inexpensive catalyst. 相似文献
214.
Qin Tu Long Pang Yanrong Zhang Maoseng Yuan Jianchun Wang Dongen Wang Wenming Liu Jinyi Wang 《中国化学》2013,31(3):304-316
Microfluidic devices, as a new miniaturized platform stemming from the field of micro-electromechanical sys-tems, have been used in many disciplines. In the field of chemical reactions, microfluidic device-based microreac-tors have shown great promise in building new chemical technologies and processes with increased speed and reli- ability and reduced sample consumption and cost. This technology has also become a new and effective tool for precise, high-throughput, and automatic analysis of chemical synthesis processes. Compared with conventional chemical laboratory batch methodologies, microfluidic reactors have a number of features, such as high mixing ef- ficiency, short reaction time, high heat-transfer coefficient, small reactant volume, controllable residence time, and high surface-to-volume ratio, among others. Combined with recent advances in microfluidic devices for chemical reactions, this review aims to give an overview of the features and applications of microfluidic devices in the field of chemical synthesis. It also aims to stimulate the development of microfluidic device applications in the field of chemical reactions. 相似文献
215.
216.
We report a novel compressed air-driven continuous-flow digital PCR (dPCR) system based on a 3D microfluidic chip and self-developed software system to realize real-time monitoring. The system can ensure the steady transmission of droplets in long tubing without an external power source and generate stable droplets of suitable size for dPCR by two needles and a narrowed Teflon tube. The stable thermal cycle required by dPCR can be achieved by using only one constant temperature heater. In addition, our system has realized the real-time detection of droplet fluorescence in each thermal cycle, which makes up for the drawbacks of the end-point detection method used in traditional continuous-flow dPCR. This continuous-flow digital PCR by the compressed air-driven method can meet the requirements of droplet thermal cycle and diagnosis in a clinical-level serum sample. Comparing the detection results of clinical samples (hepatitis B virus serum) with commercial instruments (CFX Connect; Bio Rad, Hercules, CA, USA), the linear correlation reached 0.9995. Because the system greatly simplified the traditional dPCR process, this system is stable and user-friendly. 相似文献
217.
Rong Huang Wenming Xiong Daifang Wang Longhua Guo Zhenyu Lin Lishuang Yu Kedan Chu Bin Qiu Guonan Chen 《Electrophoresis》2013,34(2):254-259
In this study, a simple and reproducible method for enantioseparation and determination of dl ‐tryptophan (dl ‐T rp) was developed by using a partial filling technique in combination with MEKC . The corresponding l ‐T rp specific DNA aptamer was used as a chiral selector. Sodium cholate was used to form the chiral micelles and to enhance the enantioseparation of the enantiomers. Effects of aptamer concentration, filling time, buffer composition, and separation voltage on the enantioseparation were evaluated. The M g2+ and Na+ concentration in separation buffer was found to effectively affect the separation efficiency and reproducibility. Under the optimal conditions, d ‐ and l ‐T rp were completely enantioseparated in less than 9 min. This aptamer‐based partial‐filling approach has the potential to be extended to the separation of other enantiomers after the replacement of corresponding specific aptamers. 相似文献
218.
Wenming Li 《Mathematische Nachrichten》2008,281(6):839-846
We give a condition which is sufficient for the two‐weight (p, q) inequalities for multilinear potential type integral operators, where 1 < p ≤ q < ∞. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
219.
220.
Abstract: Reactions of some representative organic functional compounds by the alkali metal hydrides of nanometric size have been studied. Nitrobenzene, some aldehydes, esters and organic halides are reduced with good yield and high selectivity in many cases. Nitriles are cyclotrimerized and dimethyl sulfoxide is rapidly deprotonated. 相似文献