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排序方式: 共有1432条查询结果,搜索用时 15 毫秒
1.
Ching-Te Chuang Bernstein K. Joshi R.V. Puri R. Kim K. Nowak E.J. Ludwig T. Aller I. 《Circuits and Devices Magazine, IEEE》2004,20(1):6-19
The generation-over-generation scaling of critical CMOS technology parameters is ultimately bound by nonscalable limitations, such as the thermal voltage and the elementary electronic charge. Sustained improvement in performance and density has required the introduction of new device structures and materials. Partially depleted SOI, a most recent MOSFET innovation, has extended VLSI performance while introducing unique idiosyncrasies. Fully depleted SOI is one logical extension of this device design direction. Gate dielectric tunneling, device self-heating, and single-event upsets present developers of these next-generation devices with new challenges. Strained silicon and high-permittivity gate dielectric are examples of new materials that will enable CMOS developers to continue to deliver device performance enhancements in the sub-100 nm regime. 相似文献
2.
BB Horswell CL Castiglione AE Poole LA Assael 《Canadian Metallurgical Quarterly》1993,51(2):145-9; discussion 149-50
The double-reversing Z-plasty of Furlow for closure of the soft palate was used in 34 children with various types of cleft palate. Mean age at repair was 12.8 months. Intraoperative experience was favorable, with acceptable operating time and blood loss. Length of hospitalization averaged 1.9 days. Postoperatively, two children experienced temporary stridor, which resolved within 24 to 48 hours. One child had dehiscence of the hard palate (Von Lagenbeck repair) 4 weeks postoperatively, and three children developed small oronasal fistulae. Early speech evaluation demonstrated adequate soft palate mobility in 33 of 34 patients, with observable velopharyngeal function. Twelve children had mild velar compromise, with eight exhibiting slight nasal air escape. 相似文献
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W. S. Walston I. M. Bernstein A. W. Thompson 《Metallurgical and Materials Transactions A》1991,22(6):1443-1451
The microstructure of a single-crystal nickel-base superalloy, PWA 1480, has been varied by heat treatment and hot isostatic
pressing in order to study the role of the γ/yγ′ eutectic and porosity on subsequent tensile behavior. The level of porosity
was found not to affect any of the tensile properties, while the γ/γ′ eutectic strongly influenced ductility. Eliminating
the γ/γ′ eutectic increased ductility which was attributed to the cleavage fracture of this constituent. It is proposed that
such cleavage of the γ/γ′ eutectic is initiated by the stress created from impinging slip bands, promoting shear localization,
and final fracture along {111} slip planes. The precise nature of this fracture process is discussed with emphasis on the
role of the γ/′ micro-structure. The deformation structure of PWA 1480 was also studied, and while different in some respects
from many other single-crystal superalloys, its fracture process appears to be similar.
Formerly Graduate Student, Department of Metallurgical Engineering and Materials Science, Carnegie Mellon University. 相似文献
6.
AS Astapchik EP Podvoisky IS Chebotko BM Khusid AG Merzhanov BB Khina 《Canadian Metallurgical Quarterly》1993,47(1):319-326
The labile protons of two 32-base-pair, four-arm models of immobile Holliday junctions have been studied by two-dimensional 1H nuclear magnetic resonance (NMR) spectroscopy. Overlap of resonances in the imino-imino region of two-dimensional nuclear Overhauser enhancement (NOE) spectra necessitates the use of a multi-pathway approach for obtaining sequence-specific assignments wherein all possible NOE connectivities to the labile protons are utilized, including those from the 2H of adenine, 5CH3 of thymine, and 5H of cytosine. Resonance assignments are obtained for all slowly exchanging imino and cytosine amino protons. Base-pairing up to and including the junction point is found in all four arms of both Holliday junctions. Several cross-arm NOE connectivities are identified and can be used to infer the geometry of the helical stacking domains. The two Holliday junctions studied, which differ only by the exchange of two base pairs at the branch point, appear to have opposite arm stacking geometries. These assignments form an important part of the critical background for detailed NMR analysis of Holliday junction structure and dynamics. 相似文献
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MS Ali PP Sayeski LB Dirksen DJ Hayzer MB Marrero KE Bernstein 《Canadian Metallurgical Quarterly》1997,272(37):23382-23388
Angiotensin II is the effector molecule of the renin-angiotensin system. Virtually all of its biochemical actions are mediated through a single class of cell-surface receptors called AT1. These receptors contain the structural features of the seven-transmembrane, G-protein-coupled receptor superfamily. Angiotensin II, acting through the AT1 receptor, also stimulates the Jak/STAT pathway by inducing ligand-dependent Jak2 tyrosine phosphorylation and activation. Here, we show that a glutathione S-transferase fusion protein containing the carboxyl-terminal 54 amino acids of the rat AT1A receptor physically binds to Jak2 in an angiotensin II-dependent manner. Deletional analysis, using both in vitro protocols and cell transfection analysis, showed that this association is dependent on the AT1A receptor motif YIPP (amino acids 319-322). The wild-type AT1A receptor can induce Jak2 tyrosine phosphorylation. In contrast, an AT1A receptor lacking the YIPP motif is unable to induce ligand-dependent phosphorylation of Jak2. Competition experiments with synthetic peptides suggest that each of the YIPP amino acids, including tyrosine 319, is important in Jak2 binding to the AT1A receptor. The binding of the AT1A receptor to the intracellular tyrosine kinase Jak2 supports the concept that the seven-transmembrane superfamily of receptors can physically associate with enzymatically active intracellular proteins, creating a signaling complex mechanistically similar to that observed with growth factor and cytokine receptors. 相似文献
9.
A case-mix classification system for medical rehabilitation 总被引:2,自引:0,他引:2
MG Stineman JJ Escarce JE Goin BB Hamilton CV Granger SV Williams 《Canadian Metallurgical Quarterly》1994,32(4):366-379
Dissatisfaction with Medicare's current system of paying for rehabilitation care has led to proposals for a rehabilitation prospective payment system, but first a classification system for rehabilitation patients must be created. Data for 36,980 patients admitted to and discharged from 125 rehabilitation facilities between January 1, 1990, and April 19, 1991, were provided by the Uniform Data System for Medical Rehabilitation. Classification rules were formed using clinical judgment and a recursive partitioning algorithm. The Functional Independence Measure version of the Function Related Groups (FIM-FRGs) uses four predictor variables: diagnosis leading to disability, admission scores for motor and cognitive functional status subscales as measured by the Functional Independence Measure, and patient age. The system contains 53 FRGs and explains 31.3% of the variance in the natural logarithm length of stay for patients in a validation sample. The FIM-FRG classification system is conceptually simple and stable when tested on a validation sample. The classification system contains a manageable number of groups, and may represent a solution to the problem of classifying medical rehabilitation patients for payment, facility planning, and research on the outcomes, quality, and cost of rehabilitation. 相似文献
10.
Two polypeptide antigens with molecular sizes of 34,000 daltons (34 kDa) and 38 kDa were separated from heated cells of a human clinical treponeme strain G7201 and Treponema denticola ATCC 35404, respectively. The rabbit polyclonal antisera against these antigens were produced and examined for their immunological reactions with the two heated antigens or intact spirochetal cells. Immunoblot analysis showed that the 34-kDa protein was also detected in T. denticola ATCC 35404 and ATCC 33520, and the 38-kDa protein was detected only in the two ATCC strains. Immunoelectron microscopy using the two rabbit antisera and protein A-gold complexes demonstrated that the 38-kDa protein antigen was present on the axial flagella of two T. denticola strains, and that the 34-kDa protein was located in the axial flagella of the G7201 cell, but neither in axial flagella nor on outer envelopes of the two ATCC strains cells, suggesting that the native 34-kDa axial flagellar protein of the G7201 strain may be different from that of T. denticola in terms of immunological reactivity. 相似文献