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1.
Takeshi Kondo Hiroyuki Ito Kazuhide Kusakabe Kazuhiro Ohkawa Kensuke Honda Yasuaki Einaga Akira Fujishima Takeshi Kawai 《Diamond and Related Materials》2008,17(1):48-54
The effect of CF4 plasma etching on diamond surfaces, with respect to treatment time, was investigated using scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. SEM observations and Raman spectra indicated an increase in surface roughening on a scale of 10–20 nm, and an increase in crystal defect density was apparent with treatment time in the range of 10 s to 30 min. In contrast, alteration of the diamond surface terminations from oxygen to fluorine was found to be rather rapid, with saturation of the F/C atomic ratio estimated from XPS analysis after treatment durations of 1 min and more. The redox kinetics of Fe(CN)63−/4− was also found to be significantly modified after 10 s of CF4 plasma treatment. This behavior shows that C–F terminations predominantly affect the redox kinetics compared to the effect on the surface roughness and crystal defects. The double-layer capacitance (Cdl) of the electrolyte/CF4 plasma-treated boron-doped diamond interface was found to show a minimum value at 1 min of treatment. These results indicate that a short-duration CF4 plasma treatment is effective for the fabrication of fluorine-terminated diamond surfaces without undesirable surface damage. 相似文献
2.
New technologies such as power electronics have made it possible to change continuously the impedance of a power system not only to control power flow but also to enhance stability. A power system incorporating a variable impedance apparatus such as a variable series capacitor (VSrC) and high-speed phase shifter (HSPS) is called VIPS (Variable Impedance Power System) by the authors. This paper proposes a novel control method of VIPS apparatus such as VSrC and HSPS installed at an interconnecting point for stabilizing inter-area unstable and/or oscillatory modes. The proposed design method of the control system is a kind of hierarchical decentralized control method of a large-scale power system based on a Lyapunov function. Under the proposed control scheme, each subsystem can be stabilized independently by local controllers such as AVR, speed governor and PSS, and then the whole interconnected system can be stabilized by VIPS apparatus taking into account interactions between subsystems. The effectiveness and robustness of the VIPS apparatus control are shown by numerical examples with model systems including a large-scale power system. 相似文献
3.
Norihito Kijima Kenichi Morie Shoichi Nagata Isao Shimono 《Journal of Low Temperature Physics》1996,105(5-6):1511-1516
A strontium tantalum sulfide, SrTa2S5, has a hexagonal structure with lattice constants of a =3.32 and c=24.1 Å. With decreasing temperature the electrical resistivity decreases monotonically and exhibits an abrupt superconducting transition at 3.16 K (midpoint). The diamagnetic susceptibility is observed below Tc. The magnetic susceptibility is nearly independent of temperature above Tc and shows Pauli paramagnetism. 相似文献
4.
T Ayabe H Takenaka O Takenaka A Takenaka H Nagahama H Maruyama A Yamamoto M Nagata Y Koga M Sumida M Hamada 《Canadian Metallurgical Quarterly》1996,38(2):373-381
The pMEX8-hAK1 vector was devised from the pAK plasmid (Kim J. H. et al., 1989, Protein Engineering 5, 379-386), which could directly express human adenylate kinase proteins without recombination and its single strand DNA could be withdrawn with helper phage for random site-directed mutagenesis. The conserved key residues at Lys21, Lys27, and Thr39 were engineered to obtain mutants for kinetic analysis. Three mutants were obtained as K21P, K27R, and T39S, their specific activities were strikingly reduced compared to those of wild type adenylate kinase. This pMEX8-hAK1 will be a powerful tool for site-directed mutagenesis to detect the substrate-enzyme interaction for human adenylate kinase including various other enzymes. 相似文献
5.
Michael T. Nagata John G. Speer David K. Matlock 《Metallurgical and Materials Transactions A》2002,33(10):3099-3110
To assess the potential for obtaining and utilizing titanium nitride (TiN) refinement via the increased postsolidification cooling rates associated with thin-slab casting, TiN particle size distributions were evaluated
by transmission electron microscope (TEM) examination of carbon extraction replicas. Eight commercially produced thin-slab
cast TiN steels, nominally 0.05 pct C, 1.2 pct Mn, and one conventionally cast steel were received. Thin slab samples were
taken from three locations in the production process: quenched after casting before the tunnel furnace, quenched after tunnel
furnace soaking, and the as-rolled and air-cooled final product. Effects of cooling rate were evident in the results and agree
with previously documented behavior, where precipitate size decreases with increased cooling rate. Statistical differences
in particle size between specimens from steels with different chemistries were shown. These variations result from differences
in the driving force for precipitation, rates of coarsening, and differences in volume fraction due to changes in steel composition.
The interaction of composition and processing, such as soaking in the tunnel furnace and rolling, was found to be important.
For example, the hyperstoichiometric steel (excess Ti) exhibited fine TiN after casting and soaking, but dramatic coarsening
after hot rolling. This behavior was attributed to deformation enhanced particle coarsening, or incomplete precipitation after
soaking, followed by continued growth during subsequent processing. 相似文献
6.
H. Nagata Yagang Li K.R. Voisine W.R. Bosenberg 《Photonics Technology Letters, IEEE》2004,16(11):2457-2459
Reliability for nonhermetic bias-free LiNbO/sub 3/ optical modulators is estimated from aging data in both dry and damp heat conditions. The two dominant failure modes for these devices are: 1) device performance degradation due to temperature-activated drift of the annealed proton-exchange waveguide; and 2) optical insertion loss increase due to humidity-induced deterioration of glued fiber joints. A total failure rate of 30 failures in time (FITs) is predicted for 20 years operation at 45/spl deg/C and moderate humidity conditions (40% RH). This estimate based on laboratory-test data is consistent with a field failure rate <5 FITs observed in fielded devices. 相似文献
7.
8.
Saga K. Sugasaka T. Sekiguchi M. Nagata S. Asakawa K. 《Industrial Electronics, IEEE Transactions on》1992,39(6):537-542
A reinforcement learning algorithm based on supervised learning is described. It uses associative search to discover and learn actions that make the system perform a desired task. One problem with associative search is that the system's actions are often inconsistent. In the searching process, the system's actions are always decided stochastically, so the system cannot perform learned actions more than once, even if they have been determined to be suitable actions for the desired task. To solve this problem, a neural network that can predict an evaluation of an action and control the influence of the stochastic element is used. Results from computer simulations using the algorithms to control a mobile robot are described 相似文献
9.
Lipid-Lowering Effect of Eriocitrin, the Main Flavonoid in Lemon Fruit, in Rats on a High-Fat and High-Cholesterol Diet 总被引:2,自引:0,他引:2
Yoshiaki Miyake Eriko Suzuki Satoko Ohya Syuichi Fukumoto Masanori Hiramitsu Kazuhiro Sakaida Toshihiko Osawa Yukio Furuichi 《Journal of food science》2006,71(9):S633-S637
ABSTRACT: Eriocitrin (eriodictyol 7- O -β-rutinoside) is the main flavonoid in lemon fruit. In this study, eriocitrin was investigated for its lowering effect on serum and hepatic lipids in high-fat and high-cholesterol fed rats. Rats in the control group ( N = 6) were fed a 20% lard and 1% cholesterol diet for 21 d, and rats in the 0.35% eriocitrin group ( N = 6) and 0.70% eriocitrin group ( N = 6) were fed a diet supplemented with eriocitrin 0.35% and 0.70%, respectively. The content of hepatic total cholesterol and triglyceride in the eriocitrin group was no different from that of the control group. The total cholesterol, VLDL+LDL, triglyceride, and phospholipid in the serum of the 0.35% eriocitrin group showed significantly lower concentrations than the control group ( P < 0.05), although there was no difference in the HDL concentrations among the groups. The lowering effect of eriocitrin for serum total cholesterol was thought to be caused by a decrease in VLDL+LDL. The 0.35% eriocitrin group was shown to have a significant increase in excretion of fecal bile acid ( P < 0.05) and a tendency for enhanced hepatic m-RNA levels of LDL receptor in comparison with the control group. 相似文献