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981.
We have developed a pulse programmer for magnetic resonance imaging (MRI) using a personal computer and a commercially available high-speed digital input-output board. The software for the pulse programmer was developed using C∕C++ and .NET Framework 2.0 running under the Windows 7 operating system. The pulse programmer was connected to a digital MRI transceiver using a 32-bit parallel interface, and 128-bit data (16 bits × 8 words) for the pulse sequence and the digitally detected MRI signal were transferred bi-directionally every 1 μs. The performance of the pulse programmer was evaluated using a 1.0 T permanent magnet MRI system. The acquired MR images demonstrated the usefulness of the pulse programmer. Although our pulse programmer was developed for a specially designed digital MRI transceiver, our approach can be used for any MRI system if the interface for the transceiver is properly designed. Therefore, we have concluded that our approach is promising for MRI pulse programmers. 相似文献
982.
Journal of Scheduling - In this paper, we investigate an open problem by Györgyi and Kis for a single-machine scheduling problem with a non-renewable resource (NR-SSP) and total weighted... 相似文献
983.
984.
Ronaldo Fumio Hashimoto Junior Barrera Carlos Eduardo Ferreira 《Journal of Mathematical Imaging and Vision》2000,13(1):17-33
This paper presents a general algorithm for the automatic proof that an erosion (respectively, dilation) has a sequential decomposition or not. If the decomposition exists, an optimum decomposition is presented. The algorithm is based on a branch and bound search, with pruning strategies and bounds based on algebraic and geometrical properties deduced formally. This technique generalizes classical results as Zhuang and Haralick, Xu, and Park and Chin, with equivalent or improved performance. Finally, theoretical analysis of the proposed algorithm and experimental results are presented. 相似文献
985.
Yuki Shimizu Junguo Xu Jianhua Li Hidekazu Kohira Kiyoshi Hashimoto 《Microsystem Technologies》2012,18(9-10):1597-1606
Aiming at improvements of both stability of slider flying and magnetic-recording performance under a low-clearance condition, a “narrow-grooved slider” was constructed and demonstrated at drive level. The proposed slider has narrow grooves on its center pad of an air-bearing surface for attaining a high-damping effect on pitch-mode resonant vibration of the air bearing. The relationship between the high-damping effect and the pitch-mode resonant vibration was studied, and the magnetic-recording performance at the lube/slider interaction regime was improved. In this study, first, flying-height modulation (FHM) of the slider was analyzed in the frequency domain by using a fast Fourier transform. Compared with the narrow-grooved slider, a non-grooved slider showed a larger increase in high-frequency modulation of gap flying height when the clearance was reduced to near “zero” at which the slider is starting to interact with lube. Furthermore, by means of drive-level experiments, sector error rate (SER) as a function of flying clearance was investigated. Under a low gap flying height condition, HDDs with the non-grooved slider showed slight SER degradation during slider/lube interaction. However, the narrow-grooved slider did not show any SER degradation at the same gap flying height; the damping effect of the narrow-grooved slider suppressed high-frequency FHM, thereby preventing SER degradation in the slider/lube interaction region. 相似文献
986.
Nobuo Takahashi Hirotoshi Sakagami Takuo Kamishima Shinobu Azuma Takeshi Matsuda 《Catalysis Letters》1996,36(3-4):241-244
The Rh/Y-zeolite has been found to be more active and selective for propionitrile formation from ethene and ammonia than other transition metal supported Y-zeolites. A reaction between ethene and hydrogen cyanide has been proposed as a reaction route for propionitrile formation. 相似文献
987.
We developed an oleic acid oil-in-water (o/w)-type emulsion of a new tacrolimus formulation that presented an improvement
in the delivery of the drug for oral absorption. This investigation was undertaken to assess a sustained release drug delivery
system and selective drug transfer into the lymphatic system. The whole blood concentration profiles after oral administration
at a dose of 2mg/kg and bone marrow, spleen, liver, lung, small intestine, kidney, brain, and whole blood distribution after
oral administration at a dose of 1 mg/kg of o/w emulsion formulation of tacrolimus (O/W group) were compared with those of
commercially available formulation (T group) in the rat. The mean diameter of the o/w emulsion droplets was 0.47 μm immediately
after preparation. The tacrolimus entrapping efficiency of o/w emulsion was 71.3+5.0% in 12 h and did not change for 2 d.
The area under the whole blood concentration-time curve (AUC) in the O/W group was significantly higher (P<0.01) than that in the I group. In contrast, the values of constant elimination rate and total clearance in the O/W group
were significantly lower (P<0.01) than those in the T group, with a comparative bioavailability of 115.9%. The tissue concentration of tacrolimus in
the O/W group was significantly higher levels in the bone marrow, spleen, liver, lung, and small intestine, and significantly
lower in the brain and kidney, relative to the T group. The o/w emulsion of tacrolimus may be an improved dosage form via the enteral route. 相似文献
988.
Yozo Sawaki Shuji Tada Shigeharu Hashimoto Tadashi Kawasaki 《International Journal of Fracture》1987,35(2):125-137
Fatigue crack growth rate, da/dN, of two high strength steels were examined in a laboratory air at different stress ratios, covering almost the entire range of stress intensity, K, from nearly threshold value, Kth, to final fracture. The fatigue fracture toughness, Kfc, corresponding to the final fracture in fatigue, was also determined. The lower the Kfc, the higher da/dN and reduced Kth are revealed.This correlation was analyzed quantitatively based on the four parameter Weibull function. And the stress ratio dependency of the fatigue crack propagation curve can be cleared in a successful manner.The fatigue characteristic stress intensities, Ke and Kv, are proposed to define the transition behaviour in fatigue crack growth curve, from so called region 1 to 2, and from region 2 to 3, respectively. Especially the Kv valua can be specified to be the 0.63Kfc.
Résumé On a étudié la vitesse de propagation de fissure en fatigue da/dN de deux aciers à haute résistance dans un atmosphère de laboratoire sous des sollicitations couvrant toute la gamme des intensités de contraintes variables K, depuis une valeur voisine de la valeur du seuil Kth jusqu'à celle correspondant à rupture finale.La ténacité à la rupture par fatigue Kfe correspondant à la rupture finale par fatigue a été également déterminée. II s'avère que plus Kfe est faible, plus élevée est da/dN et plus Kth est réduite. Cette correlation est analysée quantitativement en se basant sur la fonction de Weibull à quatre paramètres. On peut ainsi clarifier la manière dont le rapport de contraintes influe les courbes de propagation des fissures de fatigue.On propose de définir pas les facteurs caractéristiques d'intensité de contrainte Ke et Kv les comportements de transition de la courbe de vitesse de propagation de la fissure entre respectivement les régions dénommées 1 et 2, et 2 et 3.En particulier, on peut spécifier que la valeur Kv vaut 0,63 Kfe.相似文献
989.
A. Inoue Y. Masumoto N. Yano A. Kawashima K. Hashimoto T. Masumoto 《Journal of Materials Science》1985,20(1):97-104
Wire-shaped nickel-based amorphous alloys exhibiting high strength and good ductility combined with a high corrosion resistance were produced for Ni-Pd-Si and Ni-Pd-P alloys by melt spinning in rotating water. The amorphous wires were formed over a relatively wide range from 29 to 82 at % palladium for (Ni-Pd)82Si18 alloys and from 12 to 52 at % palladium for (Ni-Pd)80P20 alloys. The Ni-Pd-Metalloid amorphous wires had a circular cross-section and smooth surface, and their diameters were 80 to 150m. With increasing nickel content, their tensile strength, f, increased from 1340 to 1710 MPa and the elongation to fracture, f, decreased slightly from 2.2% to 1.9%. Cold-drawing the wires was an easy technique to reduce their diameter and to increase f and f up to an appropriate value of reduction in diameter. In addition, it is also effective in smoothing the wire surface. Their corrosion resistance was assumed to be sufficiently high since their polarization behaviour in 1 N H2SO4 solution was similar to palladium metal. Cold-drawing did not enhance corrosion and rather decreased apparently the active dissolution current density of some alloys owing to smoothing of the surface. 相似文献
990.
H. Yano N. Hashimoto R. Goto K. Obara O. Ishikawa T. Hata 《Journal of Low Temperature Physics》2008,150(3-4):410-414
The motion of quantized vortices is studied using a vibrating wire in superfluid 4He. A vortex filtering method provides a superfluid practically free of remanent vortices in which the vibration of a wire
cannot generate turbulence. Vortex lines are produced by cooling through the superfluid transition and remain forming bridges
between a wire and a surrounding wall. Bridged remanent vortices increase the resonance frequency of a vibrating wire: the
rate of an increase due to the remanent vortices is constant in a laminar flow regime and steeply increases in a turbulent
flow regime with increasing wire velocity. These results suggest that oscillation of the bridged vortices provides a linear
contribution to the wire vibration in the laminar flow regime, until instability occurs in the oscillation of the vortices,
causing turbulence.
相似文献