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排序方式: 共有1112条查询结果,搜索用时 15 毫秒
61.
The highly complex and multiple mechanisms responsible for the development of demyelinating neuropathies are reviewed, in particular Guillain-Barré syndrome and its variant Miller Fisher syndrome, chronic inflammatory demyelinating neuropathy, multifocal motor neuropathy, anti-myelin-associated glycoprotein neuropathy, as well as experimental models. Recent investigations into the role of auto antibodies against myelin proteins, or glycolipids have given insights into the pathogenesis of demyelinating inflammatory neuropathies. 相似文献
62.
63.
Masaaki Takehisa Hiromasa Watanabe Hirondo Kurihara Kouichi Yamaguchi Hayato Nakajima Toshiaki Yagi Terutaka Watanabe Takanobu Sugo Takeshi Suwa Shinsaku Maruyama Atsuro Kodama Takeo Shimada Yoshio Maruyama Masamichi Tohei Takeshi Wada Sueo Machi 《应用聚合物科学杂志》1979,24(8):1831-1844
Radiation-induced polymerization of ethylene using aqueous tert-butyl alcohol as medium was carried out in a large-scale pilot plant with a 50-liter central source-type reactor at a pressure of 105 to 395 kg/cm2, temperature of 30° to 80°C, mean dose rate of 4.5 × 104 to 1.9 × 105 rads/hr, ethylene feed rate of 5.5 to 23.5 kg/hr, and medium feed rate of 21 to 102 l./hr. The space–time yield and molecular weight of the polymer were in the range of 4.7 to 16.8 g/l.-hr and 1.3 × 104 to 8.9 × 104, respectively. The space–time yield and molecular weight increased with mean residence time at 30°C, whereas at 80°C they became almost independent of the time. The space–time yield increased with pressure and dose rate, slightly decreased with temperature, and was maximum at ethylene molar fraction of 0.5. The polymer molecular weight increased with pressure and ethylene molar fraction, and decreased with dose rate and temperature. The total amount of deposited polymer on the reactor wall, source case wall, and scraping blades was usually less than 1 kg, which was negligibly small for the analysis of polymerization. Continuous discharge of the polymer slurry and production of fine-powder polyethylene were successfully carried out. In the central source-type reactor, a dose rate of 1.9 × 105 rads/hr was obtained with a 60Co source of ca. 12 kCi. 相似文献
64.
OBJECTIVE: To determine the validity of new subjective memory complaints (MCs) from individuals who previously, when without dementia, denied having MCs. DESIGN: Prospective cohort. SETTING: Longitudinal, community-based study of aging and dementia. PATIENTS: One hundred thirty-three community-dwelling elderly individuals who were part of a registry for the study of conditions related to aging in North Manhattan, NY. Patients were selected if they were initially without dementia and had completed at least 2 successive annual clinical and neuropsychological evaluations and provided their own medical history. MAIN OUTCOME MEASURES: Performance on memory tests--the Buschke Selective Reminding Test and a visual memory task--and global performance on a neuropsychological test battery and clinical evaluation, by which questionable dementia or dementia was diagnosed according to a well-defined paradigm. RESULTS: Fifty-three subjects with MCs at the initial evaluation performed no worse on the memory test than the 80 subjects who denied MCs initially. There was a weak association between MCs and the diagnosis of questionable dementia at baseline (P = .04), but this was nonsignificant after adjusting for age and education. At 1-year follow-up, 21 of the 80 without baseline MCs now reported MCs. At the follow-up evaluation, these 21 subjects performed significantly worse on the memory tests, were 5 times more likely to have significant cognitive impairment, and had shown significantly greater decline over the preceding year on several of the cognitive measures than the 59 who continued to deny MCs. CONCLUSION: New MCs from individuals, who when without dementia recently denied MCs, may suggest the presence of significant impairment of memory or cognition. 相似文献
65.
Fabrication of optics by use of plasma chemical vaporization machining with a pipe electrode 总被引:1,自引:0,他引:1
Takino H Shibata N Itoh H Kobayashi T Yamamura K Sano Y Mori Y 《Applied optics》2002,41(19):3971-3977
We figure optical surfaces by plasma chemical vaporization machining (CVM) with a pipe electrode, in which an rf plasma generated at the electrode tip under approximately atmospheric pressure moves over the surfaces. We propose a shaping method in which the movement of plasma on the surfaces can be determined. Flat and aspheric surfaces are successfully figured with the desired peak-to-valley shape accuracy of 0.1 microm. The root-mean-square roughness of the resultant surfaces is at the subnanometer level. These results confirm that the plasma CVM and the shaping method have the capability to fabricate optics with high accuracy. 相似文献
66.
Kishi N. Sano T. Yamashita E. 《IEEE journal of selected topics in quantum electronics》1997,3(4):1045-1048
The paper describes the characterization of an improved fiber-optic transceiver for optical time-domain reflectometers (OTDR). The transceiver employs an active fiber ring which has both transmitter and receiver functions of OTDR. An optical circulator takes the place of the combination of a 3-dB coupler and an optical isolator in the previously reported system. Reflections from several lengths of cascaded fibers are measured to characterize the transceiver. Compared with the previous system, performance improvement of the transceiver with the optical circulator is achieved 相似文献
67.
Weidong Ding Ryota Hayashi Kohei Ochi Junya Suehiro Kiminobu Imasaka Masanori Hara Noriaki Sano Eiichi Nagao Tadao Minagawa 《Dielectrics and Electrical Insulation, IEEE Transactions on》2006,13(6):1200-1207
Chemical byproducts analysis has been recognized as a powerful diagnosis method for SF6 gas-insulated switchgear (GIS). The authors have previously demonstrated that a carbon nanotube (CNT) gas sensor could detect partial discharge (PD) generated in SF6 gas. However, PD-generated decomposition gas species, which were responsible for the CNT gas sensor response, have not been identified yet. In this paper, two kinds of experiments were conducted in order to identify the responsible decomposition gas species. At first, the decomposition gas molecules adsorbed on CNTs were analyzed by Fourier transformation infrared (FTIR) spectroscopy. FTIR absorbance was observed around 735 cm-1 after CNTs were exposed to PD generated in SF6. In the second experiment, the CNT gas sensor responses to typical SF6 decomposition products (HF and SF4) were examined. The CNT gas sensor responded to these gases in the same way as to PD generated in SF6. SF4 response was larger than HF response. Based on these results, SF 4 and SOF2 emerged as candidates for the responsible decomposition gases. Electrochemical interactions between adsorbed gas molecules and CNT were discussed based on theoretical predictions of molecular orbital calculations. The calculation results suggested that both of SOF2 and SF4 could increase the CNT gas sensor conductance 相似文献
68.
Takayuki Nakamura Yoshiaki Taguchi Masamichi Ogasa 《Electrical Engineering in Japan》2015,193(2):69-81
To reduce the loss due to ripple current in a multiphase current‐reversible chopper, we investigated electromagnetic coupling of an air‐core reactor. We derived the relationship between the amplitude of the ripple current, the duty factor, and the electromagnetic coupling coefficient, and used the results to estimate the effects of electromagnetic coupling in the design of a train energy storage system. We built reactors with electromagnetic coupling coefficients of 0.93 and 0.60. These reactors employed a new winding structure that provides an optimal electromagnetic coupling coefficient. The mass of the former type of reactor was increased by 4.4% over the conventional design, and that of the latter type of reactor was decreased by 17%. Finally, we tested the new reactors. When the chopper employs the former type of reactor and operates with equal‐phase switching and cumulative coupling, the loss due to ripple current is decreased by 11%. When the chopper employs the latter type of reactor and operates with shift‐phase switching and differential coupling, the loss is decreased to 31%. The test showed that the calculated relationships agreed with the measured values. 相似文献
69.
Nozomi Ishii Chie Sunaga Kanae Sano Dr. Chengcheng Huang Kenta Iino Dr. Yuji Matsuzaki Dr. Tadashi Suzuki Prof. Dr. Ichiro Matsuo 《Chembiochem : a European journal of chemical biology》2018,19(7):660-663
We developed a fluorescence‐quenching‐based assay system to determine the hydrolysis activity of endo‐β‐N‐acetylglucosaminidases (ENGases). The pentasaccharide derivative 1 was labeled with an N‐methylanthraniloyl group as a reporter dye at the non‐reducing end and with a 2,4‐dinitrophenyl group as a quencher molecule at the reducing end. This derivative is hydrolyzed by ENGase, resulting in an increase in fluorescence intensity. Thus, the fluorescence signal is directly proportional to the amount of the tetrasaccharide derivative, hence allowing ENGase activity to be evaluated easily and quantitatively. Using this system, we succeeded in measuring the hydrolysis activities of ENGases and thus the inhibitory activities of known inhibitors. We confirmed that this assay system is suitable for high‐throughput screening for potential inhibitors of human ENGase that might serve as therapeutic agents for the treatment of N‐glycanase 1 (NGLY1) deficiency. 相似文献
70.
Guozhang Wu Kun Zhang Kiyoji Takagi Hironari Sano Hiroshi Yui 《Polymer International》2016,65(1):102-108
The effects of morphological changes on the thermal expansion, toughness and heat resistance of polyamide‐6 (PA)/styrene–ethylene–butylene–styrene (SEBS)/polyphenylene ether (PPE) blends were investigated. Compared with the typical ‘sea (PA matrix)–island (PPE domain)–lake (SEBS in PPE domain)’ morphology, an injection‐molded ternary blend with a preferential distribution of SEBS component at the interface between PA and PPE exhibited a low coefficient of linear thermal expansion (CLTE) in the flow direction. This low CLTE was ascribed to the deformation of SEBS and PA into a co‐continuous microlayer network structure during injection molding. Consequently, the expansion preferentially occurred towards the thickness direction. Further CLTE reduction either by a change in PA viscosity or by the selective location of an inorganic filler was examined, and its influences on impact strength and heat resistance are discussed based on transmission electron microscopy observations. © 2015 Society of Chemical Industry 相似文献