OALib Journal期刊

ISSN: 2333-9721



匹配条件: “Hashiba” ,找到相关结果约17条。
Branes and Vector-like Supersymmetry Breaking Theories with Gauged Global Symmetry
Jiro Hashiba
Physics , 1998, DOI: 10.1016/S0550-3213(99)00163-7
Abstract: We show that the brane configuration describing the Izawa-Yanagida-Intriligator-Thomas (IYIT) model with gauged U(1) subgroup of the global symmetry contains inconsistent geometry, implying that there exists a stable vacuum where supersymmetry is dynamically broken.
Geometry and N=2 Exceptional Gauge Theories
Jiro Hashiba,Seiji Terashima
Physics , 1999, DOI: 10.1088/1126-6708/1999/09/020
Abstract: We find the Seiberg-Witten geometry for four dimensional N=2 supersymmetric E_6 gauge theories with massless fundamental hypermultiplets, by geometrically embedding them in type II string theories compactified on Calabi-Yau threefolds. The resulting geometry completely agrees with that of recent works, which are based on the technique of N=1 confining phase superpotentials. We also derive the Seiberg-Witten geometry for E_7 gauge theories with massive fundamental hypermultiplets.
Landau-Ginzburg Description of D-branes on ALE Spaces
Jiro Hashiba,Michihiro Naka
Physics , 2000, DOI: 10.1016/S0550-3213(00)00758-6
Abstract: We study the Landau-Ginzburg (LG) mirror theory of the non-linear sigma model on the ALE space ${\cal M}$ obtained by resolving the singularity of the orbifold ${\bf C}^2/{\bf Z}_N$. In the LG description, the data of the BPS spectrum and the lines of marginal stability are encoded in the special Lagrangian submanifolds of the mirror manifold $\hat{{\cal M}}$. Our LG description is quite simple as compared with the quiver gauge theory analysis near the orbifold point. Furthermore our mirror analysis can be applied to any point on the moduli space of ${\cal M}$.
Dual Mode Diffusion and Sorption of Sodium Chloride in Pre-Cooked Potato (Solanum tuberosum L.)
Hiroko Hashiba,Hiromi Gocho,Jiro Komiyama
Journal of Food Research (JFR) , 2012, DOI: 10.5539/jfr.v2n1p66
Abstract: For cooked potato, we report maximum showing variations of the Fick’s diffusion coefficients, D, of NaCl with total salt concentration, Ct, in the foodstuff in the temperature range, 30-98°C. The variations were successfully explained with the dual mode diffusion and sorption theory, which has been successfully applied to the diffusion of NaCl in cooked Japanese radish, solidified egg white, and pork meats. The original theory (Komiyama & Iijima, 1974) was revised by changing the definitions of the parameters for the presence of liquid water droplets in the foodstuffs. The sorption isotherms, being found to be almost linear with very slight concave upward curvatures, were explained by invoking the presence of the droplets. Two thermodynamic diffusion coefficients, DT(p) and DT(L), of NaCl of the partition and Langmuir type sorption species, respectively, in the diffusion rate determining region were estimated for the temperature range. The temperature dependences were found to show definite rises in the range of 50-70°C, suggesting the presence of a transition in the diffusion environment.
Cosmological Constraint on the String Dilaton in Gauge-mediated Supersymmetry Breaking Theories
J. Hashiba,M. Kawasaki,T. Yanagida
Physics , 1997, DOI: 10.1103/PhysRevLett.79.4525
Abstract: The dilaton field in string theories (if exists) is expected to have a mass of the order of the gravitino mass $m_{3/2}$ which is in a range of $10^{-2}$keV--1GeV in gauge-mediated supersymmetry breaking models. If it is the case, the cosmic energy density of coherent dilaton oscillation easily exceeds the critical density of the present universe. We show that even if this problem is solved by a late-time entropy production (thermal inflation) a stringent constraint on the energy density of the dilaton oscillation is derived from experimental upperbounds on the cosmic X($\gamma$)-ray backgrounds. This excludes an interesting mass region, $500keV \lesssim m_{3/2} \lesssim 1GeV$, in gauge-mediated supersymmetry breaking models.
String Junctions in B Field Background
Jiro Hashiba,Kazuo Hosomichi,Seiji Terashima
Physics , 2000, DOI: 10.1088/1126-6708/2000/09/008
Abstract: It has been recently shown that F-theory on K3 with background B fields (NSNS and RR 2-forms) is dual to the CHL string in 8 dimensions. In this paper, we reexamine this duality in terms of string junctions in type IIB string theory. It is in particular stressed that certain 7-brane configurations produce Sp gauge groups in a novel way.
Highly efficient photochemical HCOOH production from CO2 and water using an inorganic system
Satoshi Yotsuhashi,Hiroshi Hashiba,Masahiro Deguchi,Yuji Zenitani
AIP Advances , 2012, DOI: 10.1063/1.4769356
Abstract: We have constructed a system that uses solar energy to react CO2 with water to generate formic acid (HCOOH) at an energy conversion efficiency of 0.15%. It consists of an AlGaN/GaN anode photoelectrode and indium (In) cathode that are electrically connected outside of the reactor cell. High energy conversion efficiency is realized due to a high quantum efficiency of 28% at 300 nm, attributable to efficient electron-hole separation in the semiconductor's heterostructure. The efficiency is close to that of natural photosynthesis in plants, and what is more, the reaction product (HCOOH) can be used as a renewable energy source.
Cosmological Moduli Problem in Gauge-mediated Supersymmetry Breaking Theories
T. Asaka,J. Hashiba,M. Kawasaki,T. Yanagida
Physics , 1997, DOI: 10.1103/PhysRevD.58.083509
Abstract: A generic class of string theories predicts the existence of light moduli fields, and they are expected to have masses $m_\phi$ comparable to the gravitino mass $m_{3/2}$ which is in a range of $10^{-2}$keV--1GeV in gauge-mediated supersymmetry breaking theories. Such light fields with weak interactions suppressed by the Planck scale can not avoid some stringent cosmological constraints, that is, they suffer from `cosmological moduli problems'. We show that all the gravitino mass region $10^{-2}$keV $\lesssim m_{3/2} \lesssim$ 1GeV is excluded by the constraints even if we incorporate a late-time mini-inflation (thermal inflation). However, a modification of the original thermal inflation model enables the region $10^{-2}$keV $\lesssim m_{3/2} \lesssim$ 500keV to survive the constraints. It is also stressed that the moduli can be dark matter in our universe for the mass region $10^{-2}$keV $\lesssim m_\phi \lesssim$ 100keV.
Spectrum of Background X-rays from Moduli Dark Matter
T. Asaka,J. Hashiba,M. Kawasaki,T. Yanagida
Physics , 1998, DOI: 10.1103/PhysRevD.58.023507
Abstract: We examine the $X$-ray spectrum from the decay of the dark-matter moduli with mass $\sim {\cal O}(100)$keV, in particular, paying attention to the line spectrum from the moduli trapped in the halo of our galaxy. It is found that with the energy resolution of the current experiments ($\sim 10$%) the line intensity is about twice stronger than that of the continuum spectrum from the moduli that spread in the whole universe. Therefore, in the future experiments with higher energy resolutions it may be possible to detect such line photons. We also investigate the $\gamma$-ray spectrum emitted from the decay of the multi-GeV moduli. It is shown that the emitted photons may form MeV-bump in the $\gamma$-ray spectrum. We also find that if the modulus mass is of the order of 10 GeV, the emitted photons at the peak of the continuum spectrum loses their energy by the scattering and the shape of the spectrum is significantly changed, which makes the constraint weaker than that obtained in the previous works.
Tratamento endoscópico das varizes esofágicas utilizando al?as pré-atadas confeccionadas com fio de poliamida
Koyama, Francisco Susumu Corrêa;Hashiba, Kiyoshi;Bromberg, Sansom Henrique;Cappelanes, Carlos Alberto;
Arquivos de Gastroenterologia , 2006, DOI: 10.1590/S0004-28032006000400016
Abstract: backgroud: the elastic band ligation is the method of choice for treatment of esophageal varices. the action mechanism is a mechanical varices compression with thromboses. based on this concept we developed a ligature method using pretied loop made with polyamide thread for the treatment of esophageal varices. objective: the present study describes and evaluates the feasibility of the treatment of esophageal varices by the ligature method using pretied loop made with polyamide thread and analyzes the local changes of the ligations and the results, concerning safety, efficiency and complications of this procedure. patients and methods: between march, 1998 and may, 2000, 58 patients with esophageal varices were treated with pretied loop, made with polyamide thread (26 patients with schistosomiasis, 11 with alcoholic cirrhosis, 9 with hepatitis c, 5 with hepatitis b, 4 of unknown etiology, 2 with hepatitis b and c, and one with budd-chiari syndrome/ 42 men and 16 women/ average age of 47,67 ± 13,12 years, range 16-74). a plastic tube was attached to the endoscope tip featured as an accessory working channel, allowing the pretied loop made with polyamide thread to be conducted to the esophagus facilitated by a flexible metallic tube, to perform the esophageal varices ligature. a total of 506 ligatures were done, distributed in 223 sections (average of 2,26 ± 1,08 ligature, varying from 1 to 6 per section). the sessions were perform with the interval of 15 days, until the complete eradication of the esophageal varices. the ecoendoscopy was used as a complementary method to evaluate the varices eradication results: the esophageal varices were treated successfully in all patients. the complete eradication of varices was achieved in 47 (81,03%) patients. in 37 (63,79%) patients the ligatures resulted in pseudopolyps. it was not identified systemic complications or obits. the ecoendoscopy showed thrombosis in the pseudopolyps of 10 patients. the follow-up period was from 4 t

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