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101.
102.
Y Hayashi M
M
R Talukder Jinchuan Wu T Takeyama T Kawanishi N Simizu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2001,76(8):844-850
The activity of Chromobacterium viscosum lipase (glycerol‐ester hydrolase, EC 3.1.1.3) entrapped in AOT/isooctane and AOT/Tween 85/isooctane reverse micelles was significantly increased by the addition of short chain methoxypolyethylene glycols (MPEGs), taking the hydrolysis of olive oil as a model reaction. The molecular weight of MPEG had a strong effect on the lipase activity, and MPEG of nominal molecular weight 550 was found to be the most effective. To optimize the factors affecting enzymatic hydrolysis of olive oil in reverse micellar systems containing MPEG 550, the effect of various parameters, such as Wo (molar ratio of water to surfactant), pH, ionic strength, surfactant concentration and temperature were investigated. A kinetic model considering the substrate adsorption equilibrium between the bulk phase of organic solvent and the micellar phase was also successfully used to understand the enzyme activity in the presence of MPEG 550. Both the Michaelis constant and the substrate adsorption equilibrium constant were obviously reduced as compared with those obtained in the simple AOT reverse micellar system. © 2001 Society of Chemical Industry 相似文献
103.
Shaoying Lu Michailova A. Saucerman J. Yuhui Cheng Zeyun Yu Kaiser T. Li W. Bank R. Holst M. Mccammon J. Hayashi T. Hoshijima M. Arzberger P. McCulloch A. 《IEEE engineering in medicine and biology magazine》2009,28(2):46-57
This paper indicates that in ventricular myocytes when the SR (sarcoplasmic reticulum) is pharmacologically inhibited, the intracellular Ca2+concentration rapidly increases during Ca2+ entrance (0-70 ms), whereas the decay of Ca2+ is slow; in the absence of fluorescent dye, large Ca2+ concentration gradients might develop near the cell membrane; intracellular Ca2+ distribution is tightly regulated by the localization of Ca2+transporter proteins along the sarcolemma and strongly relays on the presence of mobile and stationary Ca2+ buffers. These studies also imply that in ventricular cells with intact and functional SR, the Ca2+ signal most likely would spread faster along the t-tubular system, surface membrane than to the cell interior and that in the absence of Ca2+ dye high Ca2+ gradients under the surface membrane and more uniform Ca2+ distribution in the cell interior might be expected. 相似文献
104.
A compact sodium-cooled reactor is an important candidate as a fast breeder reactor (FBR) and has been investigated in the feasibility study of FBR cycle. Due to the compact sizing of the reactor vessel, gas entrainment at the free surface of sodium coolant becomes one of the significant issues for reactor design, and it is required to clarify the criterion of gas entrainment at free surface and the tolerance. In the present study, some visualization experiments were performed in a water-air system focusing on the gas entrainment due to surface vortex and its transient phenomena. Influences of horizontal velocity were clarified by the visualization. The gas entrainment due to the surface vortex occurs intermittently. Time trends of circulation and length of gas core for the intermittent surface vortices were measured by the particle image velocimetry and visualization. It was found that the gas core length extends with time delay to the increase of circulation around the vortex. 相似文献
105.
106.
Ryuichi Tayama Katsumi Hayashi a Ryo Iwasaki Masana Sasaki Yoshinori Etoh Hiroshi Sakurai 《Nuclear Engineering and Design》2001,210(1-3):239-248
A neutron-scanning device was developed for measuring accurate neutron densities of BWR high burn-up fuels up to 65 GWd tU−1. Characteristic test of this device was done with a 252Cf source and adopted to measure axial distributions of neutron densities of BWR spent fuels with various enrichments (2.0–3.4%), which had been irradiated up to 60 GWd tU−1 at Fukushima Daini Nuclear Power Station Unit 2(2F-2). We found the measured neutron densities were proportional to about fourth power of the corresponding burn-up values. The neutron densities calculated by the ORIGEN2.1 code and various cross section libraries showed good agreements with the measured ones in profile and absolute value except for BWR-UE file mainly based on ENDF/B-IV. The BS240J32 library based on JENDL3.2 was the best among the investigated libraries. 相似文献
107.
V.Yu. Osipov A.I. Shames T. Enoki K. Takai M. Endo T. Hayashi Y. Kaburagi A.Ya. Vul' 《Diamond and Related Materials》2009,18(2-3):220-223
Prolonged (up to 2 h) heat treatment at 1600 °C of nanodiamond particles (5 nm) leads to their conversion to the mixture of quasi-spherical carbon onions and multi-shell polyhedral nanographites. Structural and magnetic properties of two (A and B) series of nanographite samples obtained at various annealing intervals were studied. XRD data show that both multi-shell nanographite samples have practically the same crystalline structures. HRTEM evidences that the most of particles obtained by short time (7 min) annealing have a spherical like shape whereas the long time (~ 2 h) annealing leads to the majority of particles having a polyhedral shape with a hollow inside. Electronic and magnetic properties of these nanocarbons were investigated by magnetic susceptibility and EPR. Annealing results in entire transformation of the EPR signal of nanodiamond to new EPR signals of various line shapes and widths. These signals are extremely sensitive to ambient oxygen. Concentrations for all EPR active spins vary from ~ 1 × 1019 spins/g (7 min) to ~ 2 × 1019 spins/g (2 h). Temperature dependences of EPR spectra' parameters were obtained for vacuum-processed samples within the range 4?600 K. Intensity vs. T plots may be well-fitted by the combination of Curie–Weiss and temperature-independent Pauli susceptibility contributions. The latter one increases on heat treatment. Significant extension of electron spin-lattice relaxation time on decreasing temperature was found. 相似文献
108.
In switched reluctance motors (SRM), the flux waveforms are nonsinusoidal and different parts of the magnetic circuit have different waveforms. This paper presents a new approach of taking account of these flux waveforms in the calculation of core losses. Relations between the fluxes of different parts of the magnetic circuits are given in the form of matrix equations, where the fluxes are expressed in terms of normalized flux pulses. Rewriting the eddy-current loss term in the Steinmetz equation in terms of the square of dB/dt and combining it with the matrix equations, eddy-current losses for the complicated flux waveforms of the stator and rotor yokes are calculated. The effect of PWM is taken into account by considering the PWM voltage waveform as dB/dt. From the matrices, it is easy to count how many times full and minor hysteresis loops occur at each pole and yoke segment. The effect of the minor loop is taken into account based on experimental results. The proposed approach gives a systematic procedure for core loss calculation. The derived equations are simple and useful in the design of SRM 相似文献
109.
Organosilane self-assembled monolayers (SAMs) have been applied to resist materials for nanolithography based on scanning probe microscopy. An organosilane SAM was prepared on Si substrates from a precursor, that is octadecyltrimethoxysilane. Using an atomic force microscope with a conductive probe, current was injected from the probe into the SAM-covered Si substrate so that the SAM was locally degraded at the probe-contacting point. Nanoscale patterns drawn on the SAM was clearly imaged by lateral force microscopy. The patterning could be conducted in air while, in vacuum at the order of 10(-6) Torr, no detectable patterns were fabricated. The presence of adsorbed water at the probe/sample junction was confirmed to be crucial for the patterning of the SAM/Si. Its mechanism was, thus, ascribed to electrochemical reactions of both the SAM and Si with adsorbed water. 相似文献
110.
Honda Y Kitaoka M Sakka K Ohmiya K Hayashi K 《Journal of Bioscience and Bioengineering》2002,93(3):313-317
The kinetic parameters of Cex, a family 10 xylanase from Cellulomonas fimi, were determined at various pH levels using soluble birchwood xylan (BWX) as a natural polymeric substrate along with three other synthetic aryl-beta-D-xylobioside substrates. Using BWX, a high level of substrate inhibition was observed which increased with decreasing pH. In contrast, typical Michaelis-Menten-type profiles were obtained using the three aryl-beta-D-xylobiosides as substrates. The k(cat) values determined using o-nitrophenyl-beta-D-xylobioside did not change as the pH increased, whereas the k(cat) values obtained with BWX, phenyl-beta-D-xylobioside and p-nitrophenyl-beta-D-xylobioside decreased, suggesting that the presence of an ortho nitro group affects the activity displayed by Cex. These differences were not observed with XynB from Clostridium stercorarium F9, a member of the same family of xylanases as Cex. These results indicate that a careful evaluation is required when employing substituted aryl-beta-D-xylobiosides in the characterization of xylanases. 相似文献