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71.
Katsuyuki Matsunaga Fumiyasu Oba Isao Tanaka Hirohiko Adachi 《Journal of Electroceramics》1999,4(1):69-80
Discrete variational (DV) Xα cluster method has been employed in calculating electronic structures of ZnO. Electronic structures of the bulk and the non-polar surface model clusters are calculated with inclusion of electrostatic potentials in the bulk and near the surface, and the electronic origins of experimental spectra and chemical bonds at the surface are examined in detail. The valence band structure constructed by Zn-3d and O-2p bands is much influenced by electrostatic potentials in ZnO. It is found that the reduction of an electrostatic potential near the surface gives rise to the difference of the valence band structures between in the bulk and at the surface. The calculated density of states at the non-polar surface of ZnO, where the Zn-3d and O-2p bands are more widely separated than in the bulk, is in good agreement with the experimental UPS. In addition, a Zn-O bond at the surface is found to show stronger covalency than that in the bulk, as a result of the change of the valence band structure due to the effect of the electrostatic potential. 相似文献
72.
M Adachi CJ Dickens J Hetherington HD Hoskins AG Iwach PC Wong N Nguyen AS Ma 《Canadian Metallurgical Quarterly》1997,104(12):2121-2125
OBJECTIVE: The purpose of this study is to determine the efficacy of initial trabeculotomy in the patient with aniridic glaucoma. DESIGN: Clinical charts were reviewed. PARTICIPANTS: Twenty-nine eyes of 16 patients with aniridia were studied. INTERVENTION: Glaucoma surgery was performed. As an initial procedure, trabeculotomy was performed in 12 eyes, other surgery was performed in 17 eyes (trabeculectomy, 5; goniotomy, 5; other, 7). MAIN OUTCOME MEASURES: Success was defined as an intraocular pressure (IOP) of 21 mmHg or lower, and no further surgery was performed. RESULTS: Ten (83%) of 12 eyes obtained IOP control after first (6 eyes) or second (4 eyes) trabeculotomy with a mean follow-up period of 9.5 years. Five eyes maintained visual acuity of 20/40 to 20/200. No serious complications were found after trabeculotomy. Three (18%) of 17 eyes were controlled with the first glaucoma surgery other than trabeculotomy (goniotomy, trabeculectomy, trabeculectomy combined with trabeculotomy, and Molteno implant). Good IOP control was obtained in 8 (47%) of 17 eyes after several surgeries with a mean follow-up period of 10.4 years. Four of 17 eyes became phthisical. CONCLUSION: This study suggests that trabeculotomy is the preferred initial operation for uncontrolled glaucoma with aniridia. 相似文献
73.
BACKGROUND AND PURPOSE: The pathogenesis of periventricular hyperintensity (PVH) is still uncertain. We investigated the relationship between PVH and risk factors for cerebrovascular diseases, especially extracranial carotid artery stenosis (ECAS). METHODS: We studied PVH and ECAS in 323 subjects between 1991 and 1994. Using 1.5-T MRI scan images, we measured PVH quantitatively at eight points and evaluated cerebral infarction. Duplex carotid sonography was performed on the carotid arteries bilaterally and used to divide the severity of ECAS into five grades. Risk factors for cerebrovascular diseases and atherosclerotic complications were assessed from the clinical history. RESULTS: Age was significantly correlated with the size of frontal and whole PVH (P < .01). Frontal PVH was significantly more severe in subjects with hypertension (P < .05). Frontal, occipital, and whole PVH were significantly more severe in subjects with a history of cerebrovascular accident (P < .01). Other risk factors and atherosclerotic complications were not correlated with PVH. There were no significant differences in the severity of PVH among the five groups of ECAS. The severity of PVH in each region was not related to ECAS. There was no significant difference in the age of patients in relation to the five grades of ECAS. However, PVH was significantly more severe in subjects with lacunar infarction or infarction of the deep border zone (P < .05). There was no relationship between PVH and cortical infarction or infarction of the cortical border zone. CONCLUSIONS: PVH correlated with age, hypertension, and past history of cerebrovascular disease but not with ECAS. PVH was significantly more severe in lacunar infarction and infarction of the deep border zone. These results suggest that small-vessel disease may underlie the pathogenesis and development of PVH. 相似文献
74.
Zahrul Fuadi Koshi Adachi Hideaki Ikeda Hisataka Naito Koji Kato 《Tribology Letters》2009,33(3):169-178
In this paper, a fundamental mechanism for creep-groan generation is investigated by adopting a simple yet effective caliper-slider
experimental model. Contact condition, which is a function of three parameters, namely normal force, contact roughness, and
material combination, is connected with the creep-groan phenomenon in terms of contact stiffness. Creep-groan generation is
determined by analyzing the frequency characteristic of the generated vibration acceleration when the sliding commences due
to a simultaneous application and release of force in the tangential and normal directions, respectively. As per the obtained
results, creep-groan occurrence or absence in the employed experimental model may be classified into three regions based upon
the value of the contact stiffness, i.e., occurrence, non-occurrence, and mixed regions. The results also indicate that creep-groan
occurrence in this caliper-slider experimental model can be avoided by controlling the value of contact stiffness in an effective
manner. 相似文献
75.
K Higo Y Kubo Y Iwatani T Ono M Maeda H Hiai T Masuda K Kuribayashi F Zhang TY Lamin A Adachi A Ishimoto 《Canadian Metallurgical Quarterly》1997,71(1):750-754
Fv-4 is a mouse gene that dominantly confers resistance to infection with Friend murine leukemia virus (F-MuLV) (S. Suzuki, Jpn. J. Exp. Med. 45:473-478, 1975). Despite complete resistance to ecotropic MuLV infection in mice carrying the Fv-4 gene, it is known that cells carrying the resistance gene in tissue culture do not always show resistance as extensive as that in vivo (H. Yoshikura and T. Odaka, JNCI 61:461-463, 1978). To investigate the immunological effect on resistance in vivo, we introduced the Fv-4 gene into BALB/c nude mice (Fv-4-/- nude[nu/nu]) by mating them with Fv-4 congenic BALB/c mice (Fv-4r/r nude+/+) and examined the susceptibility of the F2 progeny to F-MuLV. All BALB/c nude mice without the Fv-4 gene (Fv-4-/- nude[nu/nu]) were permissive to F-MuLV and developed erythroleukemia within 2 weeks after virus inoculation. The BALB/c nude mice with the Fv-4 gene (Fv-4r/r nude[nu/nu]) did not develop leukemia, and no or little virus was detected in the spleen 7 weeks after virus inoculation. The resistance to F-MuLV was dominant in (Fv-4 congenic BALB/c x BALB/c nude) F1 mice with the Fv-4r/- nude(nu/+) genotype as strictly as in (Fv-4 congenic BALB/c x BALB/c) F1 mice with the Fv-4r/- nude+/+ genotype. However, almost all BALB/c nude mice with the Fv-4r/- nude(nu/nu) genotype developed the disease within 7 weeks, and the virus was detected in all of their spleens even in the mice without leukemia. These results show that the resistance caused by the Fv-4 gene is recessive in nude mice and dominant in BALB/c mice. Some immunological effects, perhaps cell-mediated immunity, may play important roles in the resistance to F-MuLV infection in vivo in addition to the dosage effect of the Fv-4 product. 相似文献
76.
José I. Adachi 《Engineering Fracture Mechanics》2008,75(16):4666-4694
77.
78.
A heterogeneous intelligent network has been designed and implemented to allow multimedia real-time communications and messaging among local area network workstations with logically associated speakerphones and among ISDN voice/data terminals with transparent tablets on top of bitmap screens and stylus pens. The architecture, presentation, editing, storage, and retrieval of multimedia documents in these two different kinds of terminals are described. The messages and protocol conversion facilities used for multimedia communications are presented, as are the lessons learned in internetworking a local area network with ISDN 相似文献
79.
Postdetection selection diversity reception for Nyquist pulse shaped quadrature differential PSK (QDPSK) signal transmissions is addressed. Average bit error rate (BER) performance with differential and coherent demodulation is analysed for multiple-branch diversity reception under slow multipath Rayleigh fading. Diversity effects in real fading environments are verified by 8 and 16 kbit/s transmissions at 1.45 GHz carrier frequency.<> 相似文献
80.
The use of N,N-dimethylformamide (DMF) was found to be effective in the sol-gel synthesis of silica gel and glass monoliths from tetramethoxysi lane (TMOS) by the sol-gel method. Wet gel bodies prepared by gelation of TMOS-DMF-CH3OH-H2O-NH4OH (or HNO3) solutions could be dried without the occurrence of fracture or cracks when drying conditions were appropriate. Furthermore, the resultant dried gel monoliths could be converted without cracking or bloating to silica glass on heating up to 1050° C and holding there for 2 h, when the composition of the starting solution was appropriate. 相似文献