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61.
Xingyang Wu Masahiro Suzuki Tsuguyori Ohana Akihiro Tanaka 《Diamond and Related Materials》2008,17(1):7-12
Si-containing diamond-like carbon (Si-DLC) coatings with a Si content ranging between 0 (DLC) and 10 at.% were deposited by thermal electron excited plasma CVD method, and their characteristics and the tribological properties in water environment were investigated. The results showed that doped Si had little effect on the hardness and Young's modulus of the coatings. Increasing Si content reduced the friction and the wear of the mated ball, although the wear of the coatings increased. The wear of the counter ball occurred mainly in the early stage of rubbing. The Raman and XPS analysis revealed that the tribochemical reaction of Si-DLC coating occurred in water, and SiOx(OH)y gel was formed on the mated ball surface. It is considered that the tribochemical reaction is also responsible for the tribological properties of the Si-DLC coating and the counter ball, and the reaction may be accelerated by increasing the Si content. Failure-resistant capability is strongly governed by the characteristics of the coating, and can be improved by doping Si. There is an optimum Si content for increasing the failure-resistant capability and it was 6.6 at.% in this work. 相似文献
62.
This paper investigates induced voltage characteristics from an overhead transmission line by applying a method of modeling of induced voltages proposed by the authors. EMTP simulation results obtained by the modeling method agree with analytical results obtained from a well‐known formula. The induced voltages are significantly dependent on the configuration of the overhead line. A horizontal line induces the largest voltage in a gas pipeline, and the voltage induced by a vertical twin‐circuit line is about 20% smaller than that induced by a vertical single‐circuit line. The method is applied to a real pipeline system and the simulation results show reasonable agreement with field test results. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 43–51, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20465 相似文献
63.
The possible influencing factors for diamond formation which prevent non-graphitic carbons from transforming to diamond in the presence of nickel as solvent-catalyst were pursued. The relative amount of nickel to carbon did not affect the behaviour of each starting carbon on diamond formation. The existence of a graphitic structure in the starting carbon was not the major prerequisite for diamond formation. Adsorbed gases on the starting carbon and atmospheric gases in the high pressure cell were found to be the most important influencing factors for diamond formation. Hydrogen and chemical species containing hydrogen atoms were the most harmful. 相似文献
64.
The Bi2O31bM2O5 films (M=V, Nb and Ta) were prepared by a rapid quenching technique using a twin-roller type equipment. Quenched film of pure Bi2O3 partially precipitated a tetragonal phase which differs from well-known β-Bi2O3 in structure. In every (Bi2O3)0.975 (M2O5)0.025 composition (2.5% M2O5), the tetragonal phase was obtained as single phase, and the tetragonality became greater than that of the pure Bi2O3. Beyond this composition, the tetragonality decreased to form δ-phase with a fcc structure with increasing the M2O5 content. The lowest V2O5 content forming a δ-phase was 5%, while a slight tetragonality still remained in the samples containing 10% Nb2O5 and 10% Ta2O5, respectively. From the measurement of the photoconductivities of the quenched films, it was proved that a photoconduction appeared in the tetragonal phase while no photoconductivity was observed in the cubic phase. The characteristic of the photoconduction was that a remarkable decrease in the resistivity was observed when a light of ca. 500 nm in wave length was irradiated on the films. 相似文献
65.
An addition of a very small amount of Pr in Co-Ni films of a recording medium improves both corrosion resistance and frequency response. The columnar grains, which are induced by oblique incidence of evaporation, becomes remarkably finer by the addition of rare-earth elements. The TEM image of the cross section of the films shows a dense packed structure. High magnetization and a better corrosion resistance are considered to be due to the dense packed structure. The fine grain improves the frequency response. Among several rare-earth elements, especially Pr doping yields a best recording performance. 相似文献
66.
There are many multi‐input multi‐output (MIMO) systems in chemical plants, and they have multiple time delays of different length in each input and output pair. This paper explains a two‐degree‐of‐freedom (2DOF) control system based on generalized minimum variance control (GMVC) for MIMO systems. It can improve the tracking performance with respect to the reference signals and the response properties for the disturbance. The states between the sampling period can be expressed by using the modified z transform to take account of multiple time delays. Additionally, a tracking controller is designed to decouple the plant. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(1): 28–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21046 相似文献
67.
Shoya Uchida Akihiro Sato Mamiko Inamori Yukitoshi Sanada Mohammad Ghavami 《Wireless Personal Communications》2014,79(2):987-1002
Overlapped FFT has been proposed as a signal detection scheme in dynamic spectrum access to reduce the variance of the noise and improve the detection probability. However, the improvement of the detection probability in the conventional overlapped FFT is bounded with the upper limit of the overlap ratio. This paper proposes a new overlapped FFT scheme using additional frames. In the proposed scheme, in addition to the original FFT frames, new frames that consist of multiple subframes with non-continuous samples are constructed and included. It can realize the increase of the number of the FFT frames and the improvement of the detection probability compared with the conventional scheme. Numerical results through computer simulation show that the proposed scheme improves the detection probability by up to 0.07. On indoor channel models the proposed scheme also improves the detection probability. In addition, it is clarified that as the delay spread increases the detection probability reduces due to the correlation between the frames. 相似文献
68.
Akihiro Imura Tomoya Takahashi Masami Fujitsuna Tadanao Zanma Shinji Doki 《IEEJ Transactions on Electrical and Electronic Engineering》2014,9(1):83-89
Model predictive instantaneous‐current control (MPIC), which was proposed in our earlier works, enables us to achieve better instantaneous current control using mathematical models of an inverter and permanent magnet synchronous motors (PMSMs). However, dead‐time to avoid short breakdown in the inverter is not usually considered in a general inverter model. Such an unmodeled part in the inverter model prevents accurate prediction of current evolution in motor systems based on the model predictive control. Therefore, in this paper, we analyze current response resulting from the dead‐time in the MPIC, and propose a refined inverter model considering the dead‐time so that control performance is improved. The effectiveness of the proposed method is verified through simulation and experiments. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
69.
Jun‐Ichi Itoh Ikuya Sato Hideki Ohguchi Kazuhisa Sato Akihiro Odaka Naoya Eguchi 《Electrical Engineering in Japan》2005,152(3):65-73
This paper proposes a novel control method based on the virtual AC/DC/AC conversion for the matrix converter. The virtual AC/DC/AC conversion method is a very simple strategy to control the input current and the output voltage for the matrix converter. There are two new topics proposed in this paper. First, this paper proposes the minimum switching loss modulation on the virtual rectifier. In our proposed modulation, only two arms switching in the virtual rectifier using DC link current control by the virtual inverter can obtain clean sinusoidal input current. Second, a novel lean controlled carrier modulation on the virtual inverter is proposed. The leans of the triangle carrier are controlled by the duty ratio of the rectifier side pulse. The lean controlled carrier reduces harmonic distortion of the input current by avoiding interference between the rectifier control and the inverter control. These new proposals are confirmed by simulation and experimental results. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 65–73, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20144 相似文献
70.
M. Inokuchi D. Kawamura Y. Sakka K. Yabuuchi K. Yakushi I. Shirotani J. Hayashi H. Kawamura H. Inokuchi 《Journal of Low Temperature Physics》2006,142(3-4):213-217
We have studied the effect of shear stress on thin films of Pt(dpg)2 and chromic compounds, spiropyrans, by using the sapphire-anvil cell. From Raman spectra under hydrostatic pressure and shear
deformation, the shear stress effect on Pt(dpg)2 was quantitatively estimated. Then, it was observed that the color of spiropyran (1′,3′-dihydro- 1′,3′,3′-trimethyl-6-nitro-spiro
[2H-1-benzopyran-2,2′-[2H]indole]) was changed by shear stress. 相似文献