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排序方式: 共有250条查询结果,搜索用时 390 毫秒
51.
Shoji Asai Takayuki Yamazaki Akira Miyazaki Taikan Suehara Toshio Namba Tomio Kobayashi Haruhiko Saito Takatoshi Idehara Isamu Ogawa S. Sabchevski 《Journal of Infrared, Millimeter and Terahertz Waves》2012,33(7):766-776
Positronium is an ideal system for research on QED, especially in a bound state. A discrepancy (3.9σ) is found recently between measured HFS values and the QED prediction (including up-to O(α
3 log α
− 1), where α is the fine-structure constant.). It might be due to a contribution of unknown new physics or common systematic problems
in all the previous measurements. A new method to measure HFS directly is performed using a high power gyrotron. The transition
from ortho-positronium to para-positronium has been observed with 5 σ CL, which is the first observation of M1 transition in (sub)Terahertz region. New technologies of high power gyrotrons are
developed for precision spectroscopy. 相似文献
52.
Atsuhito Honda Masaki Kawano Masayoshi Ishida Keiji Sato Michiro Komatsubara Isamu Ohyama 《材料科学技术学报》2000,16(2):238-243
1. IntroductionThe total performance of inverter power supplieshas improved drastically as a result of the development of colltrol methods, higher performance in semiconductors, and higher speed, higher integration, andlower cost in integrated circuits, making it possible touse the inverter drive method in a wide range of rotating machinery which requires smaller size and/or variable speed drives. In line with these trends, magneticloss under nonsinusoidal waveform excitation, including lower … 相似文献
53.
Takahashi T. Sekiguchi T. Takemura R. Narui S. Fujisawa H. Miyatake S. Morino M. Arai K. Yamada S. Shukuri S. Nakamura M. Tadaki Y. Kajigaya K. Kimura K. Itoh K. 《Solid-State Circuits, IEEE Journal of》2001,36(11):1721-1727
A multigigabit DRAM technology was developed that features a low-noise 6F2 open-bitline cell with fully utilized edge arrays, distributed overdriven sensing for operation below 1 V, and a highly reliable post-packaging repair scheme using a stacked-flash fuse. This technology, which can be used to fabricate a 0,13-μm 180-mm2 1-Gb DRAM assembled in a 400-mil package, was verified using a 57.6-mm2, 200-MHz array-cycle, 256-Mb test chip with 0.109-μm2 cells 相似文献
54.
Isamu Kobayashi 《Information Systems》1987,12(4):343-352
In classical database theory, relational calculus has long been used in expressing query formulae and integrity constraints. In fact, relational calculus formulae are much easier to deal with than first-order formulae when evaluating queries and validating database updates in the database environment. In deductive databases, however, first-order calculus is preferred because it is convenient when proof procedures are involved. Since both situations should coexist in advanced information systems, it is very desirable to devise a conversion procedure between relational calculus and first-order calculus. In this paper, interpretation of first-order formulae in the database environment is discussed first, then tuple calculus, an extension of relational calculus, is presented. This extension enables us to describe query formulae and general rules necessary in advanced information systems, in particular, dealing with complex objects. Finally, a conversion algorithm from first-order formulae into tuple calculus formulae is presented. Several application issues are also included. 相似文献
55.
56.
Isamu Oda 《Engineering Fracture Mechanics》1988,29(6):663-671
Correlation between the Charpy absorbed energy and critical COD is investigated to obtain a useful method for estimating critical COD from Charpy V data. The round bar tension test, Charpy V-notch test and static 3-point bend test with fatigue notched specimen are carried out using mild steel, 785 MPa grade high strength steel and A5083 aluminum alloy. Correlation is found between W'c/σY and δc as well as between EW'c/σY2 and Eδc/σY, where W'c is the Charpy absorbed energy obtained by considering temperature difference between the Charpy transition temperature and COD transition temperature. The symbols σY, δc and E are yield strength, critical COD and Young's modulus, respectively. The correlations are established for various kinds of metals and over a wide temperature range including not only upper shelf range but also the transition range. 相似文献
57.
L. Morino 《Computational Mechanics》1986,1(1):65-90
The use of the Helmholtz decomposition for exterior incompressible viscous flows is examined, with special emphasis on the issue of the boundary conditions for the vorticity. The problem is addressed by using the decomposition for the infinite space; that is, by using a representation for the velocity that is valid for both the fluid region and the region inside the boundary surface. The motion of the boundary is described as the limiting case of a sequence of impulsive accelerations. It is shown that at each instant of velocity discontinuity, vorticity is generated by the boundary condition on the normal component of the velocity, for both inviscid and viscous flows. In viscous flows, the vorticity is then diffused into the surroundings: this yields that the no-slip conditions are thus automatically satisfied (since the presence of a vortex layer on the surface is required to obtain a velocity slip at the boundary). This result is then used to show that in order for the solution to the Euler equations to be the limit of the solution to the Navier-Stokes equations, a trailing-edge condition (that the vortices be shed as soon as they are formed) must be satisfied. The use of the results for a computational scheme is also discussed. Finally, Lighthill's transpiration velocity is interpreted in terms of Helmholtz decomposition, and extended to unsteady compressible flows. 相似文献
58.
Hisayoshi Itoh Masahito Yoshikawa Isamu Nashiyama Shunji Misawa Hajime Okumura Sadafumi Yoshida 《Journal of Electronic Materials》1992,21(7):707-710
Electron spin resonance (ESR) was used to study defects induced by 2MeV-proton irradiation in cubic silicon carbide (3C-SiC)
epitaxially grown on Si substrates by chemical vapor deposition. A new ESR signal labeled T5 was observed at temperatures
lower than ≈100 K in Al doped, p-type 3C-SiC epilayers irradiated. The T5 signal has anisotropic g-values of g1 = 2.0020 ± 0.0001, g2 = 2.0007 ± 0.0001,and g3 = 1.9951 ± 0.0001. The principal axes of the g-tensor were found to be along the 〈100〉 directions, indicating that the T5
center has D2 symmetry. Isochronal annealing of the irradiated epilayers showed that the T5 center was annealed at temperatures around
150° C. A tentative model is discussed for the T5 center. 相似文献
59.
Toshio Hirao Isamu Nashiyama Tomihiro Kamiya Tamotsu Suda Takuro Sakai Tsuyoshi Hamano 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1997,130(1-4):486-490
Using focused high-energy microbeams of carbon- and oxygen-ions and a high speed, wide bandwidth measurement system, we found a strong dependence of the collected charge and the transient current waveform on the position of ion incidences. Single-event charge is collected by a diffusion mechanism even when the ion strikes a position about 3 4 μm away from the lateral boundary of the p+n-junction area. 相似文献
60.
Himei Toyoji Inouye Jyunichi Nakanishi Senichiro Ukita Isamu 《Industry Applications, IEEE Transactions on》1975,(5):531-539
A circuit controlled by thyristors and having series RLC elements gives rise to a step-up phenomenon. The term step-up is defined with respect to the capacitance voltage on steady state operation, i.e., the ratio of the maximum peak value when controlled by thyristers to the peak amplitude when thyristors are short-circuited exceeds unity. The domain of possible step-up voltage is determined by the angle of displacement between current and voltage and damping factor. The step-up voltages appear across each element, i.e., not only across the capacitance, inductance, and resistance but also across the thyristors. The control characteristic has a distinctive hump phenomenon. The interrupted current results in waveform distortion, phase lag, and improved power factor. The difference of characteristics between the peak and rms values of voltages, particularly of inductance and thyristors, is large. The response time, which is evaluated by numbers of half cycles, is large when the step-up ratio becomes large. The output voltage when the circuit is used as a voltage source has a drooping characteristic. 相似文献