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31.
Mima Stanojkovski 《Archiv der Mathematik》2018,111(1):3-12
The class of evolving groups is defined and investigated, as well as their connections to examples in the field of Galois cohomology. Evolving groups are proved to be Sylow Tower groups in a rather strong sense. In addition, evolving groups are characterized as semidirect products of two nilpotent groups of coprime orders where the action of one on the other is via automorphisms that map each subgroup to a conjugate. 相似文献
32.
Yoshiaki Tsunawaki Mie Noguchi Mitsuhiro Kusaba Nobuhisa Ohigashi Masayuki Fujita Kazuo Imasaki Shin-ichiro Kuruma Kunioki Mima Sadao Nakai Chiyoe Yamanaka 《International Journal of Infrared and Millimeter Waves》1998,19(2):177-184
A hybrid planar wiggler with a period of 20 mm has been studied as the simplest one which gives the strong field including some higher harmonic components by selecting proper sizes of the ferromagnetic and the permanent magnet. Small gap length of the wiggler and small width of permendur satisfy these conditions to a certain degree.Gain analysis of FEL suggests that for high wiggler field of K>1 1.6, higher harmonic gains are improved primarily due to its strong field, and for low wiggler field of K< 1 1.6, they are mainly due to the modification of the wiggler field distribution. 相似文献
33.
Growth of bismuth oxide (most probably Bi2O3) was observed in situ in a transmission electron microscope. Bi liquid particles were dispersed on the substrates of diamond or SiO2. Introduction of oxygen up to 5 x 10-4 Pa resulted in formation of bismuth oxide (most probably Bi2O3) whiskers. The growth mechanism of the whisker was discussed in terms of a vapor-liquid-solid (VLS) mechanism. It is suggested that the liquid droplet of Bi acts as a physical catalyst for growth of bismuth oxide (most probably Bi2O3) whiskers. 相似文献
34.
Matrix isolation infrared spectroscopy has been applied to study an ozone-water complex of atmospheric interest. The complex was identified in the spectral region of three normal modes of ozone and water. Ab initio calculation at MP4(SDQ), QCISD, and CCSD(T) levels indicates the existence of only one stable conformer, which accords with the present experimental result. This conformer belongs to the Cs symmetry group where two molecular planes of ozone and water are perpendicular to the Cs symmetry plane. The binding energy was calculated to be 1.89 kcal/mol at the CCSD(T)/6-311++G(3df,3pd)//CCSD(T)/6-311++G(d,p) level of theory. The formation constant and atmospheric abundance of the ozone-water complex are estimated using the thermodynamic and spectroscopic data obtained. 相似文献
35.
An optically active helical poly(phenylacetylene) was synthesized by the copolymerization of phenylacetylenes bearing optically active hydroxy or ester groups obtained by the kinetic resolution of a racemic phenylacetylene with lipase; the helix-sense was inverted from one helix to another by the further chemical modification of the hydroxy groups with achiral bulky isocyanates or an acid chloride. 相似文献
36.
We prove the following theorem: For a connected noncomplete graph G, let τ(G): = min{dG(u) + dG(v)|dG(u, v) = 2}. Suppose G is a 3-connected noncomplete graph. Then through each edge of G there passes a cycle of length ≥ min{|V(G)|, τ (G) − 1}. © 1997 John Wiley & Sons, Inc. 相似文献
37.
Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed. 相似文献
38.
Kazuhide Kataoka 《Tetrahedron》2006,62(11):2471-2483
Prins cyclization reaction (PCR) of optically active homoallylic alcohols, RaC*H(OH)CH2CHCHCH3 (1-substituted but-2-en-1-ol), with aldehydes (RbCHO) in the presence of an acid-catalyst (HX) affords (2-Rb,3-CH3,4-X,6-Ra)-tetrasubstituted tetrahydropyrans highly stereoselectively in good yields. 相似文献
39.
Atsushi Nishikawa Kazuhide Kumakura Tetsuya Akasaka Toshiki Makimoto 《Superlattices and Microstructures》2006,40(4-6):332
We have succeeded in obtaining high critical electric fields from AlGaN layers using the p-InGaN/i-AlxGa1−xN/n-AlxGa1−xN (x=0–0.22) vertical conducting diodes grown on n-SiC substrates by low-pressure metalorganic vapor phase epitaxy (MOVPE). The breakdown voltage (VB) increases with increasing Al composition of the AlGaN layer. The corresponding critical electric fields are calculated to be 2.4 MV/cm for GaN and 3.5 MV/cm for Al0.22Ga0.78N. The critical electric field is proportional to the bandgap energy to a power of 2.5. This bandgap energy dependence is much stronger than that in the empirical expression proposed by Sze and Gibbons. The figure of merit, , increases with increasing Al composition, indicating the AlGaN-based p–i–n diodes are promising for high-power and high-temperature electronic device applications. 相似文献