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排序方式: 共有393条查询结果,搜索用时 31 毫秒
31.
RA Wain GL Berdejo WN Delvalle RT Lyon LA Sanchez WD Suggs T Ohki E Lipsitz FJ Veith 《Canadian Metallurgical Quarterly》1999,29(1):100-7; discussion 107-9
PURPOSE: Arteriography is the diagnostic test of choice before lower extremity revascularization, because it is a means of pinpointing stenotic or occluded arteries and defining optimal sites for the origin and termination of bypass grafts. We evaluated whether a duplex ultrasound scan, used as an alternative to arteriography, could be used as a means of accurately predicting the proximal and distal anastomotic sites in patients requiring peripheral bypass grafts and, therefore, replace standard preoperative arteriography. METHODS: Forty-one patients who required infrainguinal bypass grafts underwent preoperative duplex arterial mapping (DAM). Based on these studies, an observer blinded to the operation performed predicted what operation the patient required and the best site for the proximal and distal anastomoses. These predictions were compared with the actual anastomotic sites chosen by the surgeon. RESULTS: Whether a femoropopliteal or an infrapopliteal bypass graft was required was predicted correctly by means of DAM in 37 patients (90%). In addition, both anastomotic sites in 18 of 20 patients (90%) who had femoropopliteal bypass grafts and 5 of 21 patients (24%) who had infrapopliteal procedures were correctly predicted by means of DAM. CONCLUSION: DAM is a reliable means of predicting whether patients will require femoropopliteal or infrapopliteal bypass grafts, and, when a patient requires a femoropopliteal bypass graft, the actual location of both anastomoses can also be accurately predicted. Therefore, DAM appears able to replace conventional preoperative arteriography in most patients found to require femoropopliteal reconstruction. Patients who are predicted by means of DAM to require crural or pedal bypass grafts should still undergo preoperative contrast studies to confirm these results and to more precisely locate the anastomotic sites. 相似文献
32.
T. Kosaka N. Iwase S. Fujimoto T. Masuda K. Ohira M. Amatsu F. Namiki M. Ishigaki H. Ohtaka Y. Kimura J. Okayasu N. Matsui K. Umehara T. Kishi K. Kariya H. Ohki K. Irie 《Journal of the Society for Information Display》2002,10(2):163-167
We developed the world's smallest‐profile 32‐in. HDTV PDP. By improving the luminous efficiency, a luminance of 650 cd/m2 and power consumption (discharge and driving circuit) of 200 W or less was achieved. Moreover, incorporating an advanced color compensating (ACC) filter improved the PDP's color‐reproduction capability, better than that of CRTs. 相似文献
33.
High-density polyethylene films 50 μm thick were exposed to the downstream plasma flow of RF glow discharges in argon, hydrogen, or oxygen. It was found that many transvinylene and unreacted radicals remain after the argon or hydrogen plasma treatment, and that carbonyl groups are formed in the oxygen plasma treatment. The conduction current was smaller in the hydrogen-plasma treated samples and the samples exposed to oxygen or ozone after hydrogen-plasma treatment than in the untreated samples. Thermal pulse current measurements indicate that the treated surface layer traps electrons or holes and reduces the field strength at the electrode surface, thus suppressing further injection of electrons or holes. 相似文献
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35.
A. Miyata T. Matsushima H. Ohki Y. Unuma Y. Higashigaki 《Advanced functional materials》1995,5(1):37-43
Spiropyran SP1822 J-aggregate LB films show a non-linear photochromic response with a threshold against the incident light intensity of a CW dye laser. Using two laser beams operating below the threshold level intensity, the logic ‘AND’ function was found to be optically stored as an overlapping region of two incident patterns. We proposed the adoption of an LB film of spiropyran J-aggregates to store the memory matrix Tijkl as an overlapping region of learning input pattern Vij and multi-image input pattern Vkl in order to construct an optical neural network system based on Hopfield model. 相似文献
36.
Osamu Fujiwara Ikuko Mori Shinobu Ishigami Yukio Yamanaka 《Electrical Engineering in Japan》2005,153(1):17-24
An ESD (electrostatic discharge) testing is specified in the IEC 61000‐4‐2, in which the detailed waveform of the discharge current injected by an ESD gun is prescribed. However, due to lack of understanding of the discharge process, it is difficult to confirm whether or not the IEC current waveform can be injected onto actual equipment. We thus previously proposed an equivalent circuit model for the ESD gun based on its geometrical structure, and showed decisive factors for the discharge current. In this study, in order to confirm the feasibility of the above equivalent circuit model, we measured with a 6‐GHz wide‐band digital oscilloscope the discharge current through an SMA connector and the resultant magnetic near field for the contact discharge of an ESD gun. As a result, we found that both measured waveforms approximately agree with those calculated from our equivalent circuit model. We then measured with respect to charge voltages the magnetic near fields for the contact discharge of the ESD gun to the ground, which revealed that the measured waveform around the first peak is in fair agreement with the calculated one. Furthermore, we found that the magnetic field peak increases with increasing charge voltage, whose dependence can be predicted from our equivalent model. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(1): 17–24, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20194 相似文献
37.
38.
Genki Yagawa Akihiro Matsuda Hideki Kawate Shinobu Yoshimura 《International Journal of Pressure Vessels and Piping》1995,63(3):303-313
This paper describes an application of the hierarchical neural network to the generation phase stable crack growth analysis of two kinds of welded CT specimens using the GE/EPRI simplified method. One of the specimens was machined from a submerged-arc-welded plate of nuclear pressure vessel A533B Class 1 steel, the other from an electron-beam-welded plate of A533B Class 1 steel and high-strength HT80 steel. A ratio of mixture of material constants was introduced to apply the GE/EPRI method to the analysis of crack growth in the welded specimens. The best ratio of mixture was identified using the neural-network-based inverse analysis approach as follows. At first, a number of generation phase crack growth analyses based on the GE/EPRI method were tested by parametrically varying the ratio of mixture. The relationship between the ratio of mixture and the calculated crack growth behavior is called here ‘learning data sets’. The neural network was then ‘trained’ using the learning data sets. In the training process, the calculated crack growth behavior is applied to the input units of the network, while the ratio of mixture is applied to its output units in the form of teaching data. Finally, the best ratio of mixture was estimated by applying measured crack growth behavior to the input units of the ‘trained network’. The effects of material inhomogeneity on crack growth behavior in the welded specimens are discussed with respect to the best ratio of mixture obtained. 相似文献
39.
Magnesium orthosilicate (forsterite) whiskers were synthesized by an oxidation-reduction reaction in the present investigation. These whiskers were rectangular parallelepipeds, with long sides in a cross-sectional view from two to ten times as long as the short sides, and measuring from several micrometers to 200 μm wide and ∼15 mm in the elongated direction. The Mg2 SiO4 elongation was on the c-axis. The growth mechanism of the whiskers was investigated on the basis of chemical thermodynamics, and the present study revealed that the Mg2 SiO4 whiskers grew by a VS (vapor-solid) mechanism . 相似文献
40.
T Imai T Sugawara A Nishiyama R Shimada R Ohki N Seki M Sagara H Ito M Yamauchi T Hori 《Canadian Metallurgical Quarterly》1997,42(3):388-392
Ataxia telangiectasia (AT) is an autosomal recessive gene disorder, and ATM, a housekeeping gene, has been identified as the gene responsible for AT. Recently we found that another housekeeping gene, NPAT, is located upstream of ATM on human chromosome 11. The two housekeeping genes are transcribed in opposite directions and share a 0.5-kb 5' flanking sequence. The structure and organization of NPAT were determined by direct sequencing of cosmid clones carrying the gene and by application of the long and accurate (LA)-PCR method to amplify regions encompassing the exon/intron boundaries and all of the exons. The gene spans at least 44 kb and consists of 18 exons and 17 introns. It has been suggested that AT heterozygotes have an increased risk of developing cancer, especially breast cancer in women. Frequently, loss of heterozygosity at loci on 11q22-q24 has been observed in DNA isolated from tumors of the breast, uterine cervix, and colon, perhaps suggesting the location of a tumor suppressor gene in 11q22-q24. For investigation of the role of NPAT in AT and these tumors with allelic loss of 11q22-q24, appropriate primer sequences and PCR conditions for amplification of all the NPAT exons from genomic DNA were determined. We previously reported that no recombinations are found among Atm, Npat, and Acat1 (acetoacetyl-CoA thiolase) loci as determined by fine genetic linkage mapping of the mouse AT region. The results of the LA-PCR analysis using NPAT- and ACAT-specific primers and human genomic DNA allowed us to map ACAT 12 kb centromeric to NPAT. 相似文献