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排序方式: 共有146条查询结果,搜索用时 15 毫秒
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.
3.
This paper deals with model following control of a model helicopter with three degree-of-freedom. Since the decoupling matrix
is singular, a nonlinear structure algorithm is used to design the controller. Furthermore, since the model dynamics are described
linearly by unknown system parameters, a well-known parameter estimation technique is introduced. The integral type of estimation
model is proposed here since the use of the derivative type of model cannot obtain the desired estimation result. The experimental
results show the effectiveness of the proposed method.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
4.
Acicular γ-Fe2 O3 particles were heated at 90°C in alkali solution containing Co2+and Fe2+with Co2+/Fe2+ratio of 0.5. The coercivity of resultant particles increased linearly with increasing the Co2+content, and the coercivity of 900 Oe was obtained for the particles with Co2+content of 7 wt%. The shape of the particles is acicular, and an appreciable variation of morphology by the treatment in alkali solution was not observed. Cobalt-ferrite was expected to crystallize epitaxially on the surface of γ-Fe2 O3 particles, and the increase of coercivity was attributed to the magnetic anisotropy of the cobalt-ferrite. A variation of coercivity by annealing at 60°C and print-through were small compared with those of the particles in which iron were homogeneously substituted by cobalt ions. Such stability was explained by considering that a very high concentration of cobalt ions exist only on the surface of γ-Fe2 O3 particles, and the migration of cobalt ions is extremely difficult. 相似文献
5.
Tsuyoshi Nomura Masahiro Ikeda Seiji Ishiyama Kazuhide Mita Toshiki Tamura Takahiro Okada Kazuhito Fujiyama Akihiro Usami 《Journal of Bioscience and Bioengineering》2010,110(4):386-391
In insects, β-N-acetylglucosaminidase (GlcNAcase) participates in critical physiological processes such as fertilization, metamorphosis, and glycoconjugate degradation. Insects produce glycoproteins carrying paucimannosidic-type N-glycans, the terminal GlcNAc residue of which is cleaved by a GlcNAc-linkage specific GlcNAcase, also known as the fused lobes (FDL) protein. To obtain information on the structure of GlcNAcases and insight into their contribution to physiological processes, we cloned Bombyx mori FDL (BmFDL) from silkworm larvae. The full-length cDNA (1.9 kb) encoded a protein of 633 amino acids with 42% amino acid sequence identity to Drosophila melanogaster FDL (DmFDL). Recombinant BmFDL cleaved only β-1,2-linked GlcNAc residues from the α-1,3 branch of biantennary N-glycan. This substrate specificity was similar to that of DmFDL. Microsomal FDL activity was inhibited by anti-BmFDL antibodies. Taken together, our results suggest that BmFDL is a N-glycan-processing GlcNAcase in B. mori. 相似文献
6.
Purification and characterization of a novel glutamyl aminopeptidase from chicken meat 总被引:1,自引:0,他引:1
A novel glutamyl aminopeptidase (aminopeptidase A, EC 3.4.11.7) was purified from chicken meat by ammonium sulfate fractionation, ethanol fractionation, heat treatment, and successive column chromatographies of DEAE-Sepharose CL-6B and Sephadex G-200. The purified enzyme migrated as a single band on SDS-PAGE. The molecular weight of this enzyme was found to be 55,000 and 550,000 by SDS-PAGE and Sephadex G-200 column chromatographies, respectively. This enzyme hydrolyzed Glu- and Asp-, but not Leu-, Arg-, and Ala-2-naphthylamide (-2NA) at all. The optimum pH and temperature for hydrolysis of Glu-2NA was 7.5. and 70°C, respectively. Reducing agents such as cysteine and dithiothreitol inhibited the activity of this enzyme at concentrations of 1 mM. However, the activation by Ca(2+) and the inhibition by amastatin were not observed. 相似文献
7.
A study is made of the application of heterojunction bipolar transistors (HBTs) to low-noise microwave circuits. Design considerations and the low-noise performance of a Ku -band free-running oscillator using a self-aligned AlGaAs/GaAs HBT are described. The device has a novel structure in which, by utilizing SiO 2 sidewalls, the base surface area, which is the main cause of low-frequency noise, is drastically reduced. For a collector current of 1 mA, the fabricated device has base current noise power densities of 4×10-20, 6×10-21, and 2.5×10-21 A2/Hz at baseband frequencies of 1, 10, and 100 kHz, respectively. A prototype oscillator operating at 15.5 GHz has a measured output power of 6 dBm and SSB FM noise power densities of -34 dBc/Hz at 1 kHz, -65 dBc/Hz at 10 kHz, and -96 dBc/Hz at 100 kHz off-carrier, without using high-Q elements such as a dielectric resonator. The results of this study demonstrate the suitability of HBTs for low-phase-noise microwave and millimeter-wave oscillator applications 相似文献
8.
K. Hayama K. Takakura H. Ohyama S. Kuboyama S. Matsuda J.M. Rafí A. Mercha E. Simoen C. Claeys 《Microelectronics Reliability》2005,45(9-11):1376
The degradation of the electrical performance of thin gate oxide fully depleted SOI n-MOSFETs and its dependence on the radiation particles are investigated. The transistors are irradiated with 7.5-MeV protons and 2-MeV electrons at room temperature without bias. The shift of threshold voltage and the coupling effect with the degraded opposite gate are clarified. A remarkable reduction of the floating body effects is observed after irradiation. The degradation of the extracted parameters is discussed by a comparison with the damage coefficients. 相似文献
9.
A high-linearity AlGaAs/GaAs power heterojunction bipolar transistor (HBT) is developed for personal digital cellular phones. For compact chip layout, thermal design was considered. To improve power performance, proton implantation, optimum alloy condition for collector electrodes, and multiple via holes were used. A 2400-μm2-emitter-area HBT fabricated on a 0.5×0.67 mm2 substrate exhibits adjacent channel leakage powers below -53 dBc for 0.95- and 1.5-GHz π/4-shifted QPSK modulated input signals at a low collector-emitter voltage of 3.4 V. The HBT produces a 31.7-dBm output power, 50% power-added efficiency, and 15-dB linear power gain at 0.95 GHz, and produced a 31.3-dBm output power, 52% power-added efficiency, and 11.5-dB linear power gain at 1.5 GHz. These results were achieved on about one-fifth of the substrate area of conventional GaAs FETs 相似文献
10.
Numerical assessment of the seismic response of an earth embankment on liquefiable soils 总被引:2,自引:0,他引:2
Yu Huang Atsushi Yashima Kazuhide Sawada Feng Zhang 《Bulletin of Engineering Geology and the Environment》2008,67(1):31-39
This study presents a numerical assessment of the seismic behaviour of an earth embankment founded on liquefiable foundation
soils during earthquake loading. Analysis was carried out using an effective stress-based, fully coupled, finite element method.
The behaviour of the sandy soil is described by means of a cyclic elastoplastic constitutive model which was developed within
the framework of the Armstrong–Frederick type non-linear kinematic hardening concept. The numerical method and the analysis
procedure are briefly outlined and as an example, the seismic response of an earth embankment on a saturated sand foundation
is assessed. Based on the numerical results, the distinctive patterns of seismic response of the embankment are discussed.
Special emphasis is given to the computed results of excess pore water pressures, co-seismic and post-seismic deformations,
and accelerations during the seismic excitation. It has been found that the numerical model can capture fundamental liquefaction
aspects of the embankment foundation system and produce preliminary results for its seismic assessment.
相似文献