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Analytical estimates and computer simulations were undertaken to perceive the motion of negative particles through a lattice structure, the interaction being classical binary scattering. Three distinct modes of particle motion along atomic strings were found depending on the magnitude of the transverse energy and the angular momentum L of the particle with regard to the string axis. At small and large L increased scattering on the strings as compared with random penetration dominates. At medium L and negative transverse energy (bound state particles in the attractive potential) a rosette motion along the string occurs. In this case small impact parameters to the string atoms are avoided and thus an increased penetrability of the negative particles results. The influence of thermal lattice vibrations on these motions was studied. Experimentally, the negative particle motion modes manifested themselves in the penetration profiles of 20 MeV electrons through an 8 μm MgO single crystal. 相似文献
955.
Synthesis of 2-guanyl-4-(3-substituted-phenyl)thiazoles with potent histamine H2-antagonism activity
Arthur A. Santilli Anthony C. Scotese Robert L. Morris Stanley C. Bell 《Journal of heterocyclic chemistry》1991,28(8):2025-2028
The syntheses of novel 2-guanyl-4-(3-substituted-phenyl)thiazoles showing potent histamine H 2-antagonism activity is reported. The most potent compound is 17 where the substitution at the 3-position of the phenyl ring is an N-methylamidino function. 相似文献
956.
Zoë L. Sinclair Dr. Nicola L. Bell Dr. Jessica R. Bame Dr. De-Liang Long Prof. Dr. Leroy Cronin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202214203
Polyoxopalladates (POPs) are a class of self-assembling palladium-oxide clusters that span a variety of sizes, shapes and compositions. The largest of this family, {Pd84}Ac, is constructed from 14 building units of {Pd6} and lined on the inner and outer torus by 28 acetate ligands. Due to its high water solubility, large hydrophobic cavity and distinct 1H NMR fingerprint {Pd84}Ac is an ideal molecule for exploring supramolecular behaviour with small organic molecules in aqueous media. Molecular visualisation studies highlighted potential binding sites between {Pd84}Ac and these species. Nuclear Magnetic Resonance (NMR) techniques, including 1H NMR, 1H Diffusion Ordered Spectroscopy (DOSY) and Nuclear Overhauser Spectroscopy (NOESY), were employed to study the supramolecular chemistry of this system. Here, we provide conclusive evidence that {Pd84}Ac forms a 1 : 7 host-guest complex with benzyl viologen (BV2+) in aqueous solution. 相似文献
957.
Excess and interaction second virial coefficients have been measured over the temperature range 293–321 K for the systems He-N2, He-CO2, He-N2O, He-CH4, He-SF6, He-CF4 and Ar-SF6. The excess second virial coefficients BE are estimated to have an accuracy of 0.3 cm3 mol?1. 相似文献
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Mn(II)(TCNE)[C(4)(CN)(8)](1/2) (TCNE = tetracyanoethylene) exhibits a reversible pressure-induced piezomagnetic transition from a low magnetization antiferromagnetic state to a high magnetization ferrimagnetic state above 0.50 ± 0.15 kbar. In the ferrimagnetic state, the critical temperature, T(c), increases with increasing hydrostatic pressure and is ~97 K at 12.6 kbar, the magnetization increases by 3 orders of magnitude (1000-fold), and the material becomes a hard magnet with a significant remnant magnetization. 相似文献
960.
TiO2光阳极膜是染料敏化太阳能电池(DSSC)的核心部件之一,它对电池的光电转换效率起决定性作用.TiO2电极一般采用刮涂法和丝网印刷法制备.近3年,通过静电喷雾制备光阳极的方法得到国内外学者的关注.静电喷雾制备光阳极会受到多种因素的影响,如电压、流速、悬浮液浓度、喷雾距离以及喷雾时间等.但这些因素对成膜和DSSC器件性能的影响却没有得到全面的研究或者报道.本文使用静电喷雾法制备了多孔TiO2纳米膜,并研究了以其为电极的电池器件特性.经过超声充分分散的稳定TiO2乙醇悬浮液在高电压下喷雾到导电玻璃上成膜.通过改变电喷雾距离,得到了具有不同形貌的TiO:光阳极膜,并解释了其形成的机理及其对电池性能的影响.研究还表明,光阳极膜的TiC14处理能够很好地改善电池性能.通过优化,基于流速为0.8mL/h、电喷雾距离和时间分别为2.2cm和8min条件下制备的光阳极,结合TiC14处理,组装的电池在模拟太阳光源AM1.5G下光电转化效率达6.24%. 相似文献