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101.
Yuanqi Gui Baian Ji Gaoyi Yi Xiuju Li Kailian Zhang Qifeng Fu 《Molecules (Basel, Switzerland)》2021,26(6)
Herein, a novel L-arginine (L-Arg)-modified polydopamine (PDA)-coated capillary (PDA/L-Arg@capillary) was firstly fabricated via the basic amino-acid-induced PDA co-deposition strategy and employed to constitute a new chiral ligand exchange capillary electrochromatography (CLE-CEC) method for the high-performance enantioseparation of D,L-amino acids (D,L-AAs) with L-Arg as the immobilized chiral ligand coordinating with the central metal ion Zn(II) as running buffer. Assisted by hydrothermal treatment, the robust immobilization of L-Arg on the capillary inner wall could be facilely achieved within 1 h, prominently improving the synthesis efficiency and simplifying the preparation procedure. The successful preparation of PDA/L-Arg coatings in the capillary was systematically characterized and confirmed using several methods. In comparison with bare and PDA-functionalized capillaries, the enantioseparation capability of the presented CLE-CEC system was significantly enhanced. Eight D,L-AAs were completely separated and three pairs were partially separated under the optimal conditions. The prepared PDA/L-Arg@capillary showed good repeatability and stability. The potential mechanism of the greatly enhanced enantioseparation performance obtained by PDA/L-Arg@capillary was also explored. Moreover, the proposed method was further utilized for studying the enzyme kinetics of L-glutamic dehydrogenase, exhibiting its promising prospects in enzyme assays and other related applications. 相似文献
102.
Copper‐Catalyzed Aerobic Oxidative Reaction of Sulfonyl Hydrazides with Alcohols: An Easy Access to Sulfinates 下载免费PDF全文
A Cu‐catalyzed aerobic oxidative reaction between sulfonyl hydrazides and alcohols has been developed. In this reaction, sulfonyl hydrazides act as the sulfinic acid precursors to react with alcohols, resulting in sulfinic esters with up to 72 % yield. This catalytic system tolerates a wide range of sulfonyl hydrazide substrates, and represents a new strategy for the transformation of readily available sulfonyl hydrazides. 相似文献
103.
104.
Fuqiang Tian Wenbin Bu Linshuang Shi Chun Yang Yi Wang Qingquan Lei 《Journal of Electrostatics》2011,69(1):7-10
In order to investigate the trap level distribution in polymer films, a new method is proposed based on modified thermally stimulated current (TSC) theory and numerical calculation of the TSC measurement. In this method, a new function is defined to weight the contribution of every trap level to the external current. The demarcation energy is used to study the trap emptying process. The modified TSC theory shows that only the electrons with trap levels very close to the demarcation energy can significantly contribute to the external circuit at any instant temperature. Based on this method, the trap level distribution of the DuPont original polyimide film 100HN and nanocomposite polyimide film 100CR are investigated as an application example. The effectiveness of the method is confirmed by the experiments. The experimental results show that the trap level density in the 100CR PI films is about six times larger than that in the 100HN PI films through the investigated trap level ranges 06–1.3 eV. The increased traps in 100CR should be introduced by nanofillers, probably come from the interfaces formed between nanofillers and the polymer matrix. 相似文献
105.
A protocol for complete and nondestructive atomic Bell‐state analysis by using inverse engineering is presented. The setups for the Bell‐state analysis contain four atoms trapped in four separated cavities, respectively. The laser pulses designed by inverse engineering help in the manipulation of the transitions of atoms in a robust manner. By using the protocol, the information for distinguishing four Bell states of two information‐carrying atoms is encoded on two auxiliary atoms. Therefore, the four Bell states can be distinguished without being destroyed by detecting the states of the two auxiliary atoms. Moreover, as shown by the numerical simulations, the protocol has high successful probabilities to distinguish four Bell states when decoherence is considered. Thus, the protocol may provide some helpful perspectives for the quantum information tasks based on Bell states. 相似文献
106.
Lan?Ma Yi?HeEmail author Pingya?LuoEmail author Liyun?Zhang Yalu?Yu 《Journal of nanoparticle research》2018,20(2):45
Nanoparticles have been known as the useful materials in working fluids for petroleum industry. But the stabilization of nano-scaled materials in water-based working fluids at high salinities is still a big challenge. In this study, we successfully prepared the anionic polymer/multi-walled carbon nanotubes (MWNTs) composites by covalently wrapping of MWNTs with poly (sodium 4-styrenesulfonate) (PSS) to improve the stability of MWNTs in high concentration electrolytes. The PSS/MWNTs composites can automatically disperse in salinity up to 15 wt% NaCl and API brines (8 wt% NaCl?+?2 wt% CaCl2). Hydrodynamic diameters of composites were measured as a function of ionic strength and API brines by dynamic light scattering (DLS). By varying the concentration of brines, hydrodynamic diameter of PSS/MWNTs composites in brines fluctuated between 545?±?110 nm for 14 days and 673?±?171 nm for 30 days. Above results showed that PSS/MWNTs could be well stable in high salts solutions for a long period of time. After wrapped with PSS, the diameters of nanotubes changed from 30?~?40 to ~?430 nm, the thickness of wrapped polymer is about ~?400 nm by analysis of morphologies. The zeta potentials of PSS/MWNTs composites in various salinity of brines kept at approximately ??41?~???52 mV. Therefore, the well dispersion of PSS/MWNTs in high salinity is due to large negative charges of poly (sodium 4-styrenesulfonate), which provide enough electrostatic repulsion and steric repulsion to hinder compression of electric double layer caused by high concentration electrolytes. 相似文献
107.
Di Yuan Jun-Long Tian Fang Lin Dong-Wei Ma Jing Zhang Hai-Tao Cui Yi Xiao 《Frontiers of Physics》2018,13(3):130504
In this study we investigate the collective behavior of the generalized Kuramoto model with an external pinning force in which oscillators with positive and negative coupling strengths are conformists and contrarians, respectively. We focus on a situation in which the natural frequencies of the oscillators follow a uniform probability density. By numerically simulating the model, it is shown that the model supports multistable synchronized states such as a traveling wave state, π state and periodic synchronous state: an oscillating π state. The oscillating π state may be characterized by the phase distribution oscillating in a confined region and the phase difference between conformists and contrarians oscillating around π periodically. In addition, we present the parameter space of the oscillating π state and traveling wave state of the model. 相似文献
108.
Yu. N. Khanin E. E. Vdovin I. A. Larkin O. Makarovsky Yu. A. Sklyueva A. Mishchenko Yi Bo Wang A. Kozikov R. V. Gorbachev K. S. Novoselov 《JETP Letters》2018,107(4):238-242
Resonance magnetic tunneling in heterostructures formed by graphene single sheets separated by a hexagonal boron nitride barrier and bounded by two gates has been investigated in a strong magnetic field, which has allowed observing transitions between spin- and valley-split Landau levels with various indices belonging to different graphene sheets. An unexpected increase with the temperature in the interlayer tunneling conductance owing to transitions between the Landau levels in strong magnetic fields cannot be explained by existing theories. 相似文献
109.
110.
Theoretical analysis of the DNA dynamics reveals that interaction between the single solitons and plane wave implies Smale-horseshoe chaos in the double helices. Solutions of the chaotic solitons are derived from a direct perturbation technique. It is demonstrated that to produce the bounded chaotic solitons, velocities of the solit ons nust be the same and equal to propagation velocity of the plane wave in DNA. The result shows that the DNA structure may be destroyed by the long action of an electromagnetic wave. It also supplies a useful method for controlling the velocities and unboundedness of the DNA motion in a tumour cell by using a plane wave.`` 相似文献