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21.
提出了一步变换三原子W态为三原子超单态的方案。在方案中,三个五能级原子同时与双模腔发生离散相互作用。方案的优点是可以有效抵御原子自发辐射和腔衰变引起的消相干的影响。 相似文献
22.
Yong Zhang Yonghai Liu Shuai Zhang Lei Shi Wei Wang Hao Li 《Tetrahedron letters》2019,60(22):1463-1466
An acid-promoted 2-component Mannich annulation reaction of readily available acetylbenzaldehydes and secondary amines has been reported. The approach provides a simple and efficient method under mild conditions to synthesize 3-aminoindan-1-one derivatives in moderate to good yields. 相似文献
23.
M. E. Carlotti E. Ugazio S. Sapino E. Peira L. Battaglia R. Cavalli 《Journal of Dispersion Science and Technology》2013,34(10):1435-1444
Caffeic acid, a natural phenol with antioxidant and sunscreen activity, can undergo photooxidation upon UV irradiation. The photodegradation of caffeic acid at different concentrations was assessed in water, at pH 4.0 and 6.0, without and with TiO2. The study was then carried out on W/O/W emulsions entrapping the phenolic acid either in the inner or in the outer aqueous phase in the absence and in the presence of TiO2, added in the external phase (pH 6.0 or 7.0). The degradation of caffeic acid followed a pseudo-zero order kinetic with an inverse dependence from its initial concentration; at increasing pH of the medium caffeic acid degraded faster. The addition of TiO2 increased the initial photodegradation rate. Compared with water, W/O/W emulsions protected the phenol towards both the photodegradation and the photocatalytic activity of TiO2. Multiple systems allowed to incorporate caffeic acid and TiO2 in the same formulation avoiding any catalytic interactions. 相似文献
24.
Most of the commonly used microgels (MGs) are hydrophilic and tend to form oil-in-water emulsions. In this review, we discuss the function of MGs at the droplet interface in order to stabilize water-in-oil (w/o) emulsions. This topic addresses both interesting questions in fundamental research and a significant impact for applications, where the w/o emulsion type is of essential importance. Promising approaches to stabilize w/o emulsions with MGs are highlighted from different perspectives, ranging from novel MG modifications to assisted co-stabilization by adding soft or hard particles. We summarize the accumulated knowledge, evaluate the challenges and solutions, and highlight future research trends. 相似文献
25.
Chen Cao Shu-Jin Bao Dr. Xiao-Yan Tang Ze-Ming Xu Chun-Yan Ni Prof. Dr. Jian-Ping Lang 《化学:亚洲杂志》2021,16(18):2674-2680
Reactions of (NH4)2WS4 with CuCN, CuCN/1,2-bis(4-pyridyl)propane (bppa) or [Cu(MeCN)4]PF6/bppa under different reaction conditions afforded a set of two- or three-dimensional W/Cu/S cluster-based coordination polymers including {[Et4N]2[WS4Cu4(μ-CN)2(μ-I)2]}n ( 1 ), [WS4Cu4(μ-CN)2(bppa)2]n ( 2 ) and {[WS4Cu4(bppa)4](PF6)2}n ( 3 ), respectively. Compound 2 can be readily formed from reaction of 1 with bppa under solvothermal conditions. Compounds 1 and 2 feature two-dimensional networks with a “sql” topology, while 3 possesses a two-fold interpenetrated three-dimensional net with a rare “reo” topology. Compounds 1 – 3 in DMF exhibited different third-order nonlinear optical responses, and they all showed a reverse saturable absorption while 2 held a strong self-focusing effect. 相似文献
26.
K. Sai Bhavani T. Anusha J. V. Shanmukha Kumar Pradeep Kumar Brahman 《Electroanalysis》2021,33(1):97-110
Direct alcohol fuel cells (DAFCs) have been recently playing a pivotal role in electrochemical energy sources and portable electronics. Research in DAFCs has proceeded to engage major attention due to their high catalytic activity, long-term stability, portability, and low cost. Herein, we present a facile surfactant-free route to anchor bimetallic Pd−W nanoparticles supported fullerene-C60 catalyst (Pd-W@Fullerene-C60) for high-performance electrooxidation of alcohols (methanol & ethanol) for DAFCs applications. Structural, elemental composition, and morphological analysis of the proposed catalyst were carried out using UV-Vis spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy-dispersive x-ray spectroscopy (EDX). Electrochemical properties such as electrochemical activity, electrochemical active surface area (ECSA), and long-term stability of the Pd-W@Fullerene-C60 catalyst for ethanol and methanol oxidation in the alkaline medium were explored by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). Results revealed that the proposed catalyst showed enlarged ECSA, tremendous electrocatalytic activity, high poison tolerance limit, good reproducibility, and enhanced long-term stability as compared to the monometallic catalyst and commercially available catalyst (Pt/C) towards ethanol and methanol oxidation reaction. This enhanced potentiality of the Pd-W@Fullerene-C60 catalyst is due to the synergistic effect of W−Pd nanoparticles and excellent electron kinetic from fullerene support material. These findings strongly suggest the Pd-W@Fullerene-C60 catalyst as potential anode material for the alcohol oxidation reaction. 相似文献
27.
O/W微乳液中聚吡咯超微粒子的制备 总被引:4,自引:0,他引:4
选择合适的SDBS/吡咯/H2O三组分O/W微乳液与吡咯单体共存的两相体系,以单体相为单体源,在O/W三组分微乳液中进行了吡咯聚合,所得聚吡咯粒子大小仅为2~3nm,分布较均匀,且具有较好的导电性能. 相似文献
28.
29.
Kelly R. Morrison Ryan A. Allen Kevin P.C. Minbiole William M. Wuest 《Tetrahedron letters》2019,60(37):150935
Quaternary ammonium compounds (QACs) are a class of antimicrobials that have been around for over a century; nevertheless, they have found continued renewal in the structures to which they can be appended. Ranging from antimicrobial polymers to adding novel modes of action to existing antibiotics, QACs have found ongoing use due to their potent properties. However, resistance against QACs has begun to emerge, and the mechanism of resistance is still only partially understood. In this review, we aim to summarize the current state of the field and what is known about the mechanisms of resistance so that the QACs of the future can be designed to be evermore efficacious and utilized to unearth the remaining mysteries that surround bacteria’s resistance to them. 相似文献
30.
Lu Z. Ding Y. Xu Y. Yao Z. Liu Q. Lang J. 《Journal of Thermal Analysis and Calorimetry》2002,70(3):985-994
Thermal analysis on two new heterometallic sulfide clusters, [PPh4]2[WS3(CuBr)3]2 and [PPh4]2[MoS3(CuBr)3]2 (where PPh4=tetraphenyl
phosphonium, =pentamethylcyclopenta- dienyl), was carried out using a simultaneous TG-DTA unit in an atmosphere of flowing
nitrogen and at various heating rates. Supplemented using EDS method, their thermal behavior and properties, together with
the composition of their intermediate product, were examined and discussed in connection with their distinctive molecular
structure as a dianion, which provided some theoretically and practically significant information. Both clusters decomposed
in a two-step mode, but without a stable new phase composed of Mo/W-Cu-S formed during their decomposition process as we expected.
Based on TG-DTG data, four methods, i.e. Achar-Brindley-Sharp, Coats-Redfern, Kissinger and Flynn- Wall-Ozawa equation, were
used to calculate the non-isothermal kinetic parameters and to determine the most probable mechanisms.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献