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It has been reported that the major cause of earthquake damage to embankments on level ground surfaces is liquefaction of foundation soil. A few case histories, however, suggest that river levees resting on non-liquefiable foundation soil have been severely damaged if the foundation soil is highly compressible, such as thick soft clay and peat deposits. A large number of such river levees were severely damaged by the 2011 off the Pacific coast of Tohoku earthquake. A detailed inspection of the dissected damaged levees revealed that the base of the levees subsided in a bowl shape due to foundation consolidation. The liquefaction of a saturated zone, formed at the embankment base, is considered the prime cause of the damage. The deformation of the levees, due to the foundation consolidation which may have resulted in a reduction in stress and the degradation of soil density, is surmised to have contributed as an underlying mechanism. In this study, a series of centrifuge tests is conducted to experimentally verify the effects of the thickness of the saturated zone in embankments and of the foundation consolidation on the seismic damage to embankments. It is found that the thickness of the saturated zone in embankments and the drainage boundary conditions of the zone have a significant effect on the deformation of the embankments during shaking. For an embankment on a soft clay deposit, horizontal tensile strain as high as 6% was observed at the zone above the embankment base and horizontal stress was approximately half that of the embankment on stiff foundation soil. Crest settlement and the deformation of the embankment during shaking were larger for the embankment subjected to deformation due to foundation consolidation. 相似文献
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A series of oligomeric viologens were synthesized in order to investigate the polymer effect in electrochromic behavior of viologen compounds. These materials have a lower first-step reduction potential and a higher second-step reduction potential compared with monomeric viologens. As a result, they have wider potential separation, where stable viologene radical salts are produced. Spectroscopic analysis suggests that stable monomeric viologen radical salts do not exist in water, but there is some intramolecular interaction between viologen radicals of the oligomers. This intramolecular interaction is responsible for the reduction behavior and the stability of radical films of oligomeric viologens. 相似文献
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Xu D. Suemitsu T. Osaka J. Umeda Y. Yamane Y. Ishii Y. Ishii T. Tamamura T. 《Electron Device Letters, IEEE》1999,20(5):206-208
We have developed high-performance enhancement-mode InP-based modulation-doped field-effect transistors with 0.03 μm gate-length. A record high current gain cutoff frequency exceeding 300 GHz has been achieved, and the maximum extrinsic transconductance is as high as 2 S/mm with an associated drain current of 0.5 A/mm at a drain bias of 1 V. This high performance is a result of the reduction or gate length, the use of the high barrier metal Pt as gate electrodes, and most importantly the employment of the well-developed wet-etching technology that allows the formation of a very deep gate groove while retaining small side etching. The excellent E-MODFET performance opens up the possibility of implementing ever faster high-speed circuits based on direct-coupled FET logic 相似文献
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Tamamura M. Shiotsu S. Hojo M. Nomura K. Emori S. Ichikawa H. Akai T. 《Solid-State Circuits, IEEE Journal of》1992,27(11):1575-1578
A 9.5-Gb/s Si-bipolar ECL array that has a gate delay of 35 ps, a risetime of 45 ps, and a falltime of 40 ps is described. The ECL circuit design and the chip layout were optimized. A Si-bipolar process with 0.3-μm emitter width and packaging capable of accepting 10-GHz signal were used. The array was used in three key circuits of an optical communication system: a decision circuit, a 4:1 multiplexer, and a 1:4 demultiplexer. Operation of the decision circuit at 9.5 Gb/s, of the 4:1 multiplexer at 6.7 Gb/s, and of the 1:4 demultiplexer at 6.7 Gb/s were confirmed 相似文献
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BS Weeks M Nomizu A Otaka CA Weston A Okusu H Tamamura N Yamamoto N Fujii 《Canadian Metallurgical Quarterly》1995,215(2):626-631
The [Tyr5,12,Lys7]-polyphemusin II peptide (T22) inhibits HIV-1 replication in lymphocytes. The mechanism of T22 inhibition of HIV-1 replication may involve T22 competition with HIV-1 for attachment sites on the plasma membrane of targeted cells. Here we find that the T22 peptide binds to the CD4 molecule in affinity columns. We also find that antiserum to CD4 inhibits cell attachment to T22. Further CD4+ transfected cells attach to T22 while their parental cells which do not express CD4 do not attach to T22. These data demonstrate that T22 binds to the CD4 molecule and supports the hypothesis that T22 inhibits HIV-1 replication by binding to the cell surface CD4 molecule and inhibiting uptake of the virus. 相似文献
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Tohmori Y. Yoshikuni Y. Ishii H. Kano F. Tamamura T. Kondo Y. 《Electronics letters》1993,29(4):352-354
A broad range tuning of over 100 nm in tunable DBR lasers with superstructure grating (SSG) is reported. The SSG reflectors for 100 nm were designed and patterned by electron beam lithography. 1.55 mu m DBR lasers with SSG reflector operate in a single mode with a tuning range of 83 nm under CW conditions. With inclusion of the multimode operating region, the tuning range becomes as wide as 103 nm.<> 相似文献
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Dr. Takuya Kobayakawa Kento Ebihara Yuzuna Honda Dr. Masayuki Fujino Dr. Wataru Nomura Prof. Naoki Yamamoto Dr. Tsutomu Murakami Prof. Hirokazu Tamamura 《Chembiochem : a European journal of chemical biology》2019,20(16):2101-2108
C34, a 34-mer fragment peptide, is contained in the HIV-1 envelope protein gp41. A dimeric derivative of C34 linked through a disulfide bridge at its C terminus was synthesized and found to display potent anti-HIV activity, comparable with that of a previously reported PEGylated dimer of C34REG. The reduction in the size of the linker moiety for dimerization was thus successful, and this result might shed some light on the mechanism of the suppression of six-helix bundle formation by these C34 dimeric derivatives. Addition of a Gly-Cys(CH2CONH2)-Gly-Gly motif at the N-terminal position of a C34 monomeric derivative significantly increased the anti-HIV-1 activity. This moiety functions as a new pharmacophore, and this might provide a useful insight into the design of potent HIV-1 fusion inhibitors. 相似文献