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111.
The characteristic polynomial of a multiarrangement 总被引:1,自引:0,他引:1
Takuro Abe 《Advances in Mathematics》2007,215(2):825-838
Given a multiarrangement of hyperplanes we define a series by sums of the Hilbert series of the derivation modules of the multiarrangement. This series turns out to be a polynomial. Using this polynomial we define the characteristic polynomial of a multiarrangement which generalizes the characteristic polynomial of an arrangement. The characteristic polynomial of an arrangement is a combinatorial invariant, but this generalized characteristic polynomial is not. However, when the multiarrangement is free, we are able to prove the factorization theorem for the characteristic polynomial. The main result is a formula that relates ‘global’ data to ‘local’ data of a multiarrangement given by the coefficients of the respective characteristic polynomials. This result gives a new necessary condition for a multiarrangement to be free. Consequently it provides a simple method to show that a given multiarrangement is not free. 相似文献
112.
An investigation of dispersed liquid–liquid two-phase turbulent swirling flow in a horizontal pipe is conducted using a particle
tracking velocimetry (PTV) technique and a shadow image technique (SIT). Silicone oil with a low specific gravity is used
as immiscible droplets. A swirling motion is given to the main flow by an impeller installed in the pipe. Fluorescent tracer
particles are applied to flow visualization. Red/green/blue components extracted from color images taken with a digital color
CCD camera are used to simultaneously estimate the liquid and droplet velocity vectors. Under a relatively low swirl motion,
a large number of droplets with low specific gravity tend to accumulate in the central region of the pipe. With increasing
droplet volume fraction, the liquid turbulence intensity in the axial direction increases while that in the wall-normal direction
decreases in the central region of the pipe. In addition, the turbulence modification in the present flow is strongly dependent
on the droplet Reynolds number; however, the interaction of droplet-induced turbulences is significant due to vortex shedding,
particularly at high droplet Reynolds numbers and higher droplet volume fraction. 相似文献
113.
Hidemitsu Aoki Takuro Masuzumi Daisuke Watanabe M.K. Mazumder Hiroshi Sota Chiharu Kimura Takashi Sugino 《Applied Surface Science》2009,255(6):3635-3638
Variations in the composition and bonds of boron carbon nitride (BCN) film caused due to an oxygen (O2) plasma ashing process are investigated for a low dielectric constant (low-k) insulating film for next generation LSI devices. The O2 plasma treatment is preformed for BCN samples with various C compositions. The etching rate of BCN films with an O2 plasma decreases with increasing C composition. The reaction of O atoms is suppressed in the BCN film with a high C composition. B-N and B-C bonds with lower bond energies are easily broken by the O2 plasma and replaced by the generation of B-O, N-O, and C-O bonds. The B-atom concentration for all samples is decreased significantly by the O2 plasma treatment. Ion bombardment may play a more dominant role than the O-atom reaction in the etching of the BCN film. The existence of C-N bonds with a high bonding energy may suppress etching and incorporation of O atoms. 相似文献
114.
115.
Microscopic analysis of carbon phases induced by femtosecond laser irradiation on single-crystal SiC
Takuro Tomita Tatsuya Okada Hiroyuki Kawahara Ryota Kumai Shigeki Matsuo Shuichi Hashimoto Masako Kawamoto Makoto Yamaguchi Shigeru Ueno Emi Shindou Akira Yoshida 《Applied Physics A: Materials Science & Processing》2010,100(1):113-117
Elemental analysis of femtosecond laser-induced modified region was carried out by transmission electron microscopy and Raman spectroscopy. The relative Raman intensities of a-SiC were higher in the peripheral region of laser irradiated spot where the fine ripple was formed. On the contrary, the relative Raman intensities of a-Si were higher in the central region where the coarse ripple was formed. This result suggests that the material migration has strongly occurred in the higher fluence region. On the other hand, the mapping of carbon atoms in the topmost amorphous layer of laser induced periodic structures did not show any significant segregation. In addition, Raman spectroscopic analysis showed that the domain size of carbon was very small (< 1 nm). From these facts, it was found that the carbon atoms were uniformly distributed in the topmost amorphous layer and were randomly connected without forming any observable fine particles. 相似文献
116.
Takuro Abe 《Journal of Algebraic Combinatorics》2013,38(1):65-78
We give a lower bound on the number of chambers divided by a family of lines in the real plane. Also, a sufficient condition for 3-arrangements to be free is given in terms of chambers. To prove them, we give the upper bound on differences of exponents for balanced 2-multiarrangements in terms of the cardinality of hyperplanes. 相似文献
117.
Makoto Yamaguchi Shigeru Ueno Ryota Kumai Keita Kinoshita Toshiaki Murai Takuro Tomita Shigeki Matsuo Shuichi Hashimoto 《Applied Physics A: Materials Science & Processing》2010,99(1):23-27
Raman spectroscopy was performed to investigate microscopic structural changes associated with a ripple structure formation
initiated by femtosecond laser irradiation on the surface of single-crystal silicon carbide. The amorphous phases of silicon
carbide, silicon, and carbon were observed. The intensity ratio between amorphous silicon carbide and silicon changed discretely
at the boundary between fine and coarse ripples. The physical processes responsible for the formation of the ripple structure
are discussed. 相似文献
118.
119.
Shigeyuki Yagi Takuro Matsunaga Katsushi Hamakubo Hiroyuki Nakazumi 《Research on Chemical Intermediates》2009,35(8-9):1033-1052
In order to investigate effective dopants to induce chiral nematic liquid crystalline phases, novel freebase (FbBL) and zinc bilinone (ZnBL) derivatives bearing optically active aliphatic groups ((S)-3,7-dimethyloctyls) at the peripheral positions were prepared. From the CD spectra, it was confirmed that M-helicity in the bilinone frameworks was modestly enriched for ZnBLs, whereas helicity was hardly induced for FbBLs except for the o-xylylene-spaced dimer. When N-(4-methoxybenzylidene)-4-butylaniline (MBBA) was doped with the bilinone derivatives, the chiral nematic phase was effectively induced, and the helical twisting powers (βMs) ranged from ?95 to ?159 μm?1. The control experiment using (S)-3,7-dimethyl-1-phenyloctane (βM = +14 μm?1) clearly showed that the induced chiral helical frameworks of FbBL and ZnBL predominantly contribute to chiral nematic induction of MBBA. 相似文献
120.
Toshie Fujishima Takuro Komatsu Yuri Takao Wataru Yonamine Tsutomu Suenaga Hiroaki Isono Masayuki Morikawa Keisuke Takaguchi 《Tetrahedron》2019,75(8):1098-1106
Five novel vitamin D analogues (2a, 2b, 3a, 3b and 4) bearing an aromatic side chain have been designed and synthesized in a convergent manner. The requisite CD-ring synthons (10a–c) were prepared from C22 aldehyde (5) using four- or five-step procedures. Using turbo-Grignard reagents allowed aromatic side chains with a polar functional moiety to be installed in a single step with excellent yields. A preliminary biological evaluation using bovine thymus vitamin D receptor (VDR) suggested that incorporating a carboxylic acid instead of the C25-hydroxy group had a positive effect on the VDR affinity compared with the corresponding esters. 相似文献