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排序方式: 共有183条查询结果,搜索用时 62 毫秒
41.
42.
M. Uda H. Endo K. Maeda Y. Sasa M. Kobayashi 《Zeitschrift für Physik A Hadrons and Nuclei》1981,300(1):1-6
The excitation conditions where both direct Coulomb and shake-off processes concur to multiply ionize fluorineK andL shells were adopted in this experiment; 6MeV/amu p,α and C4+ impacts. The ion induced FKα satellites, measured for a series of F bearing compounds, showed significant chemical effects on their intensity distributions. Such effects are explained well with an FL-vacancy rearrangement model. Without any theoretical prediction, rearrangement probabilities or widths of FL shells were estimated by use of a reference compound with high ionicity, i.e. NaF. A linear relationship between FL widths and covalencies of compounds was found for a wide variety of fluorides. For the same compounds, the absolute values of the FL-vacancy rearrangement probabilities or the FL-shell widths obtained here were the same as those estimated from pure direct Coulomb and pure shake-off excitations, respectively. Other models than theL-vacancy rearrangement's are also discussed and eliminated. 相似文献
43.
We study Langevin dynamics describing nonequilibirum steady states. Employing the phenomenological framework of steady-state thermodynamics constructed by Oono and Paniconi [Prog. Theor. Phys. Suppl. 130, 29 (1998)], we find that the extended form of the second law which they proposed holds for transitions between steady states and that the Shannon entropy difference is related to the excess heat produced in an infinitely slow operation. A generalized version of the Jarzynski work relation plays an important role in our theory. 相似文献
44.
45.
M.Cvetinov D.Z.Obadovic M.Stojanovic A.Vajda K.Fodor-Csorba N.Eber I.Ristic 《中国物理 B》2014,(9):341-346
In this work, five mixtures with different concentrations of banana-shaped and calamitic compounds have been prepared and subsequently studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction on non-oriented samples. The phase sequences and molecular parameters of the binary systems are presented. 相似文献
46.
A class of kinetically constrained models with reflection symmetry is proposed as an extension of the Fredrickson–Andersen model. It is proved that the proposed model on the square lattice exhibits a freezing transition at a non-trivial density. It is conjectured by numerical experiments that the known mechanism of the singular behaviors near the freezing transition in a previously studied model (spiral model) is not responsible for that in the proposed model. 相似文献
47.
Sasa Duric Fanni D. Sypaseuth Santina Hoof Emma Svensson Prof. Dr. C. Christoph Tzschucke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17456-17463
The synthesis of asymmetrically substituted 2,2′:6′,2′′‐terpyridines is reported. First, palladium‐catalyzed C? H arylation of pyridine N‐oxides with substituted bromopyridines gave 2,2′‐bipyridine N‐oxides, which were further arylated in a second step to form 2,2′:6′,2′′‐terpyridine N‐oxides. Yields of up to 77 % were obtained with N‐oxides bearing an electron‐withdrawing ethoxycarbonyl substituent in the 4‐position. Pd(OAc)2 with either P(tBu)3 or P(o‐tolyl)3 was used as the catalyst. Cyclometalated complexes derived from Pd(OAc)2 and these phosphines were also effective. K3PO4 as the base gave better results than K2CO3. Subsequent deoxygenation with H2 and Pd/C as the catalyst gave the asymmetrically substituted 2,2′:6′,2′′‐terpyridines in near quantitative yield. This reaction sequence significantly reduces the number of steps required in comparison with known cross‐coupling methods and therefore allows convenient and scalable access to substituted terpyridines. 相似文献
48.
We study the protocol dependence of the mechanical properties of granular media by means of computer simulations. We control
a protocol of realizing disk packings in a systematic manner. In 2D, by keeping material properties of the constituents identical,
we carry out compaction with various strain rates. The disk packings exhibit the strain rate dependence of the critical packing
fraction above which the pressure becomes non-zero. The observed behavior contrasts with the well-studied jamming transitions
for frictionless disk packings. We also observe that the elastic moduli of the disk packings depend on the strain rate logarithmically.
Our results suggest that there exists a time-dependent state variable to describe macroscopic material properties of disk
packings, which depend on its protocol. 相似文献
49.
Yu Peng Xitao Liu Zhihua Sun Chengmin Ji Lina Li Zhenyue Wu Sasa Wang Yunpeng Yao Maochun Hong Junhua Luo 《Angewandte Chemie (International ed. in English)》2020,59(10):3933-3937
Polarized light detection is attracting increasing attention for its wide applications ranging from optical switches to high‐resolution photodetectors. Two‐dimensional (2D) hybrid perovskite‐type ferroelectrics combining inherent light polarization dependence of bulk photovoltaic effect (BPVE) with excellent semiconducting performance present significant possibilities. Now, the BPVE‐driven highly sensitive polarized light detection in a 2D trilayered hybrid perovskite ferroelectric, (allyammonium)2(ethylammonium)2Pb3Br10 ( 1 ), is presented. It shows a superior BPVE with near‐band gap photovoltage of ca. 2.5 V and high on/off switching ratio of current (ca. 104). Driven by the superior BPVE, 1 exhibits highly sensitive polarized light detection with a polarization ratio as high as ca. 15, which is far more beyond than those of structural anisotropy‐based monocomponent devices. This is the first realization of BPVE‐driven polarized light detection in hybrid perovskite ferroelectrics. 相似文献
50.