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排序方式: 共有772条查询结果,搜索用时 359 毫秒
41.
Kojima Hiroomi Kinoshita Yasuaki Hikita Mitsuaki Tabuchi Toyoji 《Electronics letters》1980,16(12):445-446
Velocity and propagation loss of surface shear waves are measured on free-space and metallised surfaces of LiNbO3 crystals along the x-axis of rotated Y-cut plates as a function of rotation about the x-axis between 35° and 70°. The coupling factor obtained from the velocities is 0.20 for a 35° rotated Y-cut plate and 0.09 for a 70° plate. The coupling factor changes linearly with the rotation angle. The propagation losses over the whole range measured here are less than 5 dB/cm on both free-space and on metallised surfaces. These losses are fairly low and very favourable for fabricating s.a.w. filters. 相似文献
42.
43.
In response to the rapidly increasing demand for communication facilities, microwave relay systems have played an important role in Japan's telecommunications network because of their economy and capability for broadband transmission. Their progress has been marked during the past 20 years and this development has been supported by advances in such diverse fields as radio propagation, antennas, microwave and electronic circuitry, electron devices, and, particularly, in solid-state techniques. This article reviews the history of microwave relay systems and describes the past and expected future contributions of the solid-state technology to these systems. 相似文献
44.
45.
The interaction of lipid peroxides with cellular proteins has been postulated to contribute to cellular aging. A potential
target for such effects is tubulin, the building block of microtubules. We examined the concentration-dependent effects of
phosphatidylcholine hydroperoxides on the ability of tubulin to polymerize into microtubules. The results demonstrated that
even very low concentrations of peroxides were sufficient to interfere with the tubulin and, therefore, the microtubule function.
Decreased tubulin activity (as measured by tubulin GTPase activity) showed correlation with the modification of methionine
and cysteine in tubulin and a change in the tubulin conformational state as indicated by fluorescence and ultraviolet spectroscopic
measurements. As no effect on electric conductivity was observed, indicating that modulation of ionic binding was not involved,
the interaction mechanism may be a hydrophobic one. 相似文献
46.
The objective of this work was to study field-induced silver injection into Li2O · 2SiO2 glass by the techniques of secondary ion mass spectrometry and thermally stimulated polarization/depolarization current (TSPC/TSDC), with an emphasis on the comparison experiments between gold and silver electrodes. For both anode materials, accumulation of lithium was found near the cathode. The blocking nature of the gold anode was demonstrated by the closeness of the observed and estimated width of the alkali-depleted region near the anode. For silver-anode samples, field-induced silver injection as well as lithium conduction occured and increased the TSPC slope from that of the gold-anode samples. 相似文献
47.
48.
In this paper,a technique for designing 3-D separable-denominator state-spacedigital filters is developed. The design process is divided intotwo phases. First, the coefficient matrices related to stabilityare constructed for the filter to be stable by using alternatingvariable method. Next, the other matrices are obtained by solvinglinear equations. These phases are repeated until there is nosignificant change in the squared error function. 相似文献
49.
Oleg Vasylkiv Yoshio Sakka Yasuaki Maeda Valeriy V. Skorokhod 《Journal of the American Ceramic Society》2005,88(3):639-644
A uniformly aggregated 3 mol% yttria-stabilized tetragonal zirconia nano-powder (3Y-TZP) was prepared using thermal hydrolysis and the ultrasonic deagglomeration technique. The possibility of nano-engineering of Pt–3Y-TZP composite aggregates was studied. The as-synthesized Pt nano-particles (∼2 nm) were impregnated into zirconia nano-aggregates (20–45 nm). The morphology manipulation technique allowed production of the composite zirconia-based aggregates in which a significant fraction of the Pt particles was embedded into the densified zirconia aggregates. Using the colloidal technique and low-temperature (1150°C) sintering, we prepared the Pt-zirconia (0.5–1.5 wt% of platinum) nano-composites with average 3Y-TZP grain sizes of 120 nm, and with the platinum grains size in the range of 20–60 nm. The catalytic properties of composite Pt–3Y-TZP nano-composites were studied and described. 相似文献
50.
Akira Doi 《Journal of Materials Science》1989,24(2):749-755
From the analysis of complex impedance and admittance data of (Agl)75(Ag4P2O7)25 glass, an Ag+-ion conductor, it was revealed that the sample can be approximated by a seriesRC
1 circuit at high temperature, with the capacitorC
1 arising from the charge-carrier depleted region near the anode which develops as conduction proceeds, and by a parallelRC
2 circuit at low temperature, with the capacitorC
2 arising from the saturated value for ionic polarization of, say, the silver-iodine pairs as well as from the relaxation effect of the Ag+ ions for conduction. TheC
1 andC
2 values were found to be almost temperature-independent at peak frequencies of the distorted semicircles in respective complex planes, with the ratioC
1/C
2 as large as 104. 相似文献