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排序方式: 共有302条查询结果,搜索用时 15 毫秒
291.
Takashima D. Watanabe S. Nakano H. Oowaki Y. Ohuchi K. Tango H. 《Solid-State Circuits, IEEE Journal of》1994,29(4):441-447
New gate logics, standby/active mode logic I and II, for future 1 Gb/4 Gb DRAMs and battery operated memories are proposed. The circuits realize sub-l-V supply voltage operation with a small 1-μA standby subthreshold leakage current, by allowing 1 mA leakage in the active cycle. Logic I is composed of logic gates using dual threshold voltage (Vt) transistors, and it can achieve low standby leakage by adopting high Vt transistors only to transistors which cause a standby leakage current. Logic II uses dual supply voltage lines, and reduces the standby leakage by controlling the supply voltage of transistors dissipating a standby leakage current. The gate delay of logic I is reduced by 30-37% at the supply voltage of 1.5-1.0 V, and the gate delay of logic II is reduced by 40-85% at the supply voltage of 1.5-0.8 V, as compared to that of the conventional CMOS logic 相似文献
292.
S. Kobayashi N. Hosoda R. Takashima 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1997,390(3):939-430
The radiation shielding effects of some tungsten alloys were evaluated using 133Ba(356 keV) and 137Cs(660 keV)γ-ray sources. Tungsten carbide had about the same effect as the commonly used lead, while tungsten-copper alloy gave as good a performance as tungsten. The results of transmittance measurements for these materials, as well as of their Monte-Carlo simulation, are reported. 相似文献
293.
A Imamura K Sugai S Watanabe F Hamada T Kurashige S Takashima 《Canadian Metallurgical Quarterly》1994,36(5):527-530
Stool samples from 880 residents in an urban slum in Dhaka, Bangladesh, were collected on 3 occasions over one year, and examined for intestinal parasites. Information on many potential risk factors for infection was obtained by questionnaire from a respondent in each household studied. In a crude univariate analysis of the data, several of the factors were found to be significantly associated with Strongyloides stercoralis infection. Most of these factors were co-variate with one another, and with poverty generally. Using Mantel-Haenszel chi 2 tests to control for confounding effects of each variable individually, the following 4 factors remained independently associated with S. stercoralis infection: respondent's use of a community latrine rather than a private latrine, living in a house with an earth floor rather than a cement floor, being of Bihari ethnicity, and being 7-10 years of age. Implications of these results for the epidemiology and control of strongyloidiasis are briefly discussed. 相似文献
294.
A Takashima M Murayama O Murayama T Kohno T Honda K Yasutake N Nihonmatsu M Mercken H Yamaguchi S Sugihara B Wolozin 《Canadian Metallurgical Quarterly》1998,95(16):9637-9641
Families bearing mutations in the presenilin 1 (PS1) gene develop Alzheimer's disease. Previous studies have shown that the Alzheimer-associated mutations in PS1 increase production of amyloid beta protein (Abeta1-42). We now show that PS1 also regulates phosphorylation of the microtubule-associated protein tau. PS1 directly binds tau and a tau kinase, glycogen synthase kinase 3beta (GSK-3beta). Deletion studies show that both tau and GSK-3beta bind to the same region of PS1, residues 250-298, whereas the binding domain on tau is the microtubule-binding repeat region. The ability of PS1 to bring tau and GSK-3beta into close proximity suggests that PS1 may regulate the interaction of tau with GSK-3beta. Mutations in PS1 that cause Alzheimer's disease increase the ability of PS1 to bind GSK-3beta and, correspondingly, increase its tau-directed kinase activity. We propose that the increased association of GSK-3beta with mutant PS1 leads to increased phosphorylation of tau. 相似文献
295.
Using a local density functional calculation, we investigate the adsorption energies, geometries and electronic structures of single Cu2+ and Fe2+ ions on a Si(100) surface. The adsorption energy results reveal that both ions are stably adsorbed in a hollow site; from this site, Cu2+ is located at 0.51 Å and Fe2+ is located at 0.41 Å from the surface, respectively. The adsorption energy of Cu2+ is about 1.5 times larger than that of Fe2+. This means that Cu2+ is strongly adsorbed on the silicon surface. From the analysis of spin density, we find that Cu2+strongly attracts the electrons of the silicon surface, because spin density is delocalized in the silicon backbone. As a result, the 3d orbital of Cu2+ becomes more similar to the closed-shell state compared to that of Fe 2+. This means that the core electronic state of Cu2+ is closer to the neutral atom, which is qualitatively confirmed by XPS measurements. 相似文献
296.
M Itsuno K Makiyama K Muta K Furukawa K Hara S Tabata H Soda S Ikeda H Takashima Y Fukuda 《Canadian Metallurgical Quarterly》1995,27(9):700-703
A rare case of adult T-cell leukemia (ATL) in which multiple lymphomatous polyposis (MLP) was revealed throughout the entire gastrointestinal tract is reported here. The polypectomy specimens taken from the rectum revealed infiltration of neoplastic T-cells, the integration of HTLV-1 proviral DNA, and increased CD4 (OKT4) and CD25 (IL-2R) cells. The analysis of surface markers of the lymphocytes from polypoid lesions may be useful for elucidating cell tropism and homing properties in the gastrointestinal tract. Although MLP has always been associated with B-cell lymphoma in the Western world, it is important for clinicians and pathologists to be aware that MLP may be caused by the infiltration of ATL cells. 相似文献
297.
Junsu Park Shunsuke Murayama Motofumi Osaki Hiroyasu Yamaguchi Akira Harada Go Matsuba Yoshinori Takashima 《Advanced materials (Deerfield Beach, Fla.)》2020,32(39):2002008
The host–guest interaction as noncovalent bonds can make polymeric materials tough and flexible based on the reversibility property, which is a promising approach to extend the lifetime of polymeric materials. Supramolecular materials with cyclodextrin and adamantane are prepared by mixing host polymers and guest polymers by planetary ball milling. The toughness of the supramolecular materials prepared by ball milling is approximately 2 to 5 times higher than that of supramolecular materials prepared by casting, which is the conventional method. The materials maintain their mechanical properties during repeated ball milling treatments. They are also applicable as self-healable bulk materials and coatings, and they retain the transparency of the substrate. Moreover, fractured pieces of the materials can be re-adhered within 10 min. Dynamic mechanical analysis, thermal property measurements, small-angle X-ray scattering, and microscopy observations reveal these behaviors in detail. Scars formed on the coating disappear within a few seconds at 60 °C. At the same time, the coating shows scratch resistance due to its good mechanical properties. The ball milling method mixes the host polymer and guest polymer at the nano level to achieve the self-healing and recycling properties. 相似文献
298.
Oxidized LDL (oxLDL) has been shown to activate the sphingomyelinase pathway producing ceramide in vascular smooth muscle
cells. Therefore ceramide, which is a biologically active lipid causing apoptosis in a variety of cells, may be involved in
the apoptotic action of oxLDL. In this study, we examined whether cholesterol enriched diets affected ceramide metabolism
and oxidation product of LDL, represented by degradation of apolipoprotein B-100 (apoB) in apoE-deficient (apoE−/−) mice. ApoE−/− and wild type mice were fed a standard (AIN-76) diet or 1% cholesterol-enriched diet for 8 weeks. Tissue ceramide levels
were analyzed using electrospray tandem mass spectrometry (LC-MS/MS). Ceramide levels in the plasma and the liver of apoE−/− mice were intrinsically higher than those of the wild type. In apoE−/− mice, dietary cholesterol significantly increased several ceramides and degradation products of apoB in plasma compared to
those fed the control diet. Dietary cholesterol did not affect tissue ceramide levels in the wild type mice. Based on these
results, plasma ceramides possibly correlate with the increase in LDL oxidation and are a risk factor for atherosclerosis. 相似文献
299.
Tomoya Fujisawa Shigeru Hamada Norimitsu Koga Daisuke Sasaki Toshihiro Tsuchiyama Nobuo Nakada Kazuki Takashima Masaharu Ueda Hiroshi Noguchi 《International Journal of Fracture》2014,185(1-2):17-29
In this study, in order to define a fatigue crack initiation unit, the relationship between the fatigue crack initiation process and the crystal structure in the pearlitic steel used for railroad rails was examined and fatigue tests, focusing on crack initiation, were performed. The fracture surfaces were analyzed using a scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The crystal structure of the pearlitic steel is composed of “pearlitic colonies” that have the same lamellar structure direction and “pearlitic blocks” that have the same ferrite crystal direction. The SEM and EBSD results revealed that the crack initiation depends on the pearlitic colonies. Therefore, we defined the characteristic dimension for fatigue crack initiation as the pearlitic colony size. However, for safety purposes, the pearlitic block size should be considered the engineering definition of the fatigue crack initiation unit, since decreasing the pearlitic block size should cause an improvement in the fatigue limit of pearlitic steel. 相似文献
300.
Takumi Takashima Junji Yamaguchi Masayoshi Ishida 《Progress in Photovoltaics: Research and Applications》2008,16(8):669-677
A disconnection detection method using an earth capacitance measurement in photovoltaic (PV) module string was experimentally studied. In the experiments with disconnections between PV modules in the string, the earth capacitance of the string was increased in proportion to the module number, and this feature resulted in that the disconnection position between the modules could be estimated by comparing the earth capacitance value of the failed string with that of the good string. Since the earth capacitance was not affected by the irradiance change, the detection method could be applied anytime to locate the disconnection position in the string without the effect of the irradiance change. Moreover, this method could be applied not only to the string consisting of the crystalline Si modules but also to the string consisting of the amorphous Si modules. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献