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1.
A. Goyal E. D. Specht Z. L. Wang D. M. Kroeger J. A. Sutliff J. E. Tkaczyk J. A. Deluca L. Masur G. N. Riley 《Journal of Electronic Materials》1994,23(11):1191-1197
Microstructural origins for reduced weak-link behavior in high-Jc melt-processed YBCO, spray pyrolyzed thick films of Tl-1223, metallic precursor Y-124 polycrystalline powder-in-tube (PIT)
wires and PIT Bi-2212/2223 are discussed. Since the materials studied are the highest Jc, polycrystalline, high-Tc superconductors fabricated worldwide, the results provide important guidelines for further improvements in superconducting
properties, thereby enabling practical applications of these materials. It is found that strongly linked current flow within
domains of melt-processed 123 occurs effectively through a single crystal path. In c-axis oriented, polycrystalline Tl-1223
thick films, local in-plane texture has been found to play a crucial role in the reduced weak-link behavior. Formation of
“colonies” of grains with a common c-axis and modest in-plane misorientation was observed. Furthermore, a colony boundary
in general has a varying misorientation along the boundary. Large regions comprised primarily of low angle boundaries were
observed. Percolative transport through a network of such small angle boundaries appears to provide the nonweak-linked current
path. Although powder-in-tube BSCCO 2212 and 2223 also appear to have a “colony” microstructure, there are some important
differences. Colonies in BSCCO consist of stacks of grains with similar c-axis orientation in contrast to colonies in Tl-1223
films where few grains are stacked on top of one another. Furthermore, most grains within a colony in BSCCO have the same
lateral dimensions as that of the colony, resulting largely largely in “twist” boundaries. Further microstructural characterization
of high-Jc PIT 2212 and 2223 is currently underway. In the case of Y-124 wires, weak macroscopic in-plane texture is found. Additional
measurements are underway to determine if a sharper, local in-plane texture also exists. It is found that in three of the
four types of superconductors studied, reduced weak-link behavior can be ascribed to some degree of biaxial alignment between
grains, either on a “local” or a “global” scale. 相似文献
2.
Pradeep Bhartiya Neha Kaushik Linh N. Nguyen Sander Bekeschus Kai Masur Klaus-Dieter Weltmann Nagendra Kumar Kaushik Eun Ha Choi 《International journal of molecular sciences》2022,23(6)
Excess amounts of redox stress and failure to regulate homeostatic levels of reactive species are associated with several skin pathophysiologic conditions. Nonmalignant cells are assumed to cope better with higher reactive oxygen and nitrogen species (RONS) levels. However, the effect of periodic stress on this balance has not been investigated in fibroblasts in the field of plasma medicine. In this study, we aimed to investigate intrinsic changes with respect to cellular proliferation, cell cycle, and ability to neutralize the redox stress inside fibroblast cells following periodic redox stress in vitro. Soft jet plasma with air as feeding gas was used to generate plasma-activated medium (PAM) for inducing redox stress conditions. We assessed cellular viability, energetics, and cell cycle machinery under oxidative stress conditions at weeks 3, 6, 9, and 12. Fibroblasts retained their usual physiological properties until 6 weeks. Fibroblasts failed to overcome the redox stress induced by periodic PAM exposure after 6 weeks, indicating its threshold potential. Periodic stress above the threshold level led to alterations in fibroblast cellular processes. These include consistent increases in apoptosis, while RONS accumulation and cell cycle arrest were observed at the final stages. Currently, the use of NTP in clinical settings is limited due to a lack of knowledge about fibroblasts’ behavior in wound healing, scar formation, and other fibrotic disorders. Understanding fibroblasts’ physiology could help to utilize nonthermal plasma in redox-related skin diseases. Furthermore, these results provide new information about the threshold capacity of fibroblasts and an insight into the adaptation mechanism against periodic oxidative stress conditions in fibroblasts. 相似文献
3.
Discusses 4 phases of the traumatic process associated with severe burn injuries in children. Predisposing factors (i.e., emotional disturbances) in the preinjury phase are discussed. The acute phase centers on treatment directed toward physiological stabilization. The intermediate phase, in which skin grafts and other painful medical procedures are performed, is characterized by dependency on adults and regression, behavior problems, and such emotional reactions as blaming the parents. Strategies for preparing children for and helping them cope with pain are discussed. The rehabilitative phase often involves difficulties in social readjustment. Strategies for dealing with each phase are presented, most of which focus on prevention efforts. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
M Mann JH Shelhamer H Masur VJ Gill W Travis D Solomon J Manischewitz F Stock HC Lane FP Ognibene 《Canadian Metallurgical Quarterly》1997,155(5):1723-1728
This study assessed the presence of cytomegalovirus (CMV) in bronchoalveolar lavage (BAL) in three subpopulations of HIV-infected patients and correlated its presence with clinical status during 3 mo of follow-up. Nineteen asymptomatic volunteers, six patients with CMV retinitis, and 46 patients with acute pulmonary symptoms underwent BAL and were assessed for CMV by cytopathology, conventional shell vial cultures, and antigen detection. Transbronchial biopsies were also obtained when possible and evaluated for histopathologic changes of CMV. All patients were followed for approximately 3 mo. Cytomegalovirus was detected in BAL in nine of 19 (47%) asymptomatic volunteers, in all six patients with CMV retinitis, and in 33 of 46 (72%) patients with pulmonary symptoms. Only one symptomatic patient with a positive CMV BAL culture developed clinically significant CMV pulmonary disease; this patient developed disseminated CMV and died. The only other death occurred in a patient with CMV retinitis who developed staphylococcal bacteremia. None of the asymptomatic volunteers or patients with CMV retinitis developed evidence of CMV pneumonia or any other organ disease with CMV. Cytomegalovirus is frequently detected in BAL from HIV-infected patients regardless of their pulmonary symptoms and its presence does not clinically predict significant pulmonary morbidity or mortality in 3 mo of follow-up. 相似文献
5.
A. Otto Ph.D. C. Craven S.B. D. Daly B.S. E. R. Podtburg B.S. J. Schreiber Ph.D. L. J. Masur 《JOM Journal of the Minerals, Metals and Materials Society》1993,45(9):48-52
The metallic precursor process, used in the production of high-temperature superconducting ceramics, exploits the relatively high formability of the metallic state to fabricate multifilament wires with excellent transport and mechanical properties. Multifilament wires, containing 9,583 filaments, exceed by tenfold the filament counts achieved by any other process. Oxide critical current densities of 17.7 kA/cm2 at 77 K in self-field surpass the best electrical performance reported for any other process used to fabricate multifilament composite wires. The mechanical properties of these wires approach the behavior of ideal composites, resulting in the flexibility, durability, and strain tolerance required for large-scale use in power generation, distribution, and end-use applications such as motors and current limiters. 相似文献
6.
Gentry W. Doyle; Street W. Jeannie; Masur Frank T.; Asken Michael J. 《Canadian Metallurgical Quarterly》1981,12(2):224
Surveyed American Psychological Association-approved doctoral and internship programs in clinical and counseling psychology regarding training opportunities in medical psychology. 42 graduate and 65 internship programs responded. Results indicate that the majority of both types of programs offered didactic and experiential training, including diagnostic and therapeutic activities with a wide variety of medical/surgical patients. There appears to be a sufficient number of faculty psychologists with special interest and/or expertise in this area to adequately prepare new psychologists for employment in medical centers and other types of medical settings. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Dual-Color InAs/GaSb Superlattice Focal-Plane Array Technology 总被引:1,自引:0,他引:1
Robert Rehm Martin Walther Frank Rutz Johannes Schmitz Andreas Wörl Jan-Michael Masur Ralf Scheibner Joachim Wendler Johann Ziegler 《Journal of Electronic Materials》2011,40(8):1738-1743
Within a very few years, InAs/GaSb superlattice technology has proven its suitability for high-performance infrared imaging
detector arrays. At the Fraunhofer Institute for Applied Solid State Physics (IAF) and AIM Infrarot-Module GmbH, efforts have
been focused on developing mature fabrication technology for dual-color InAs/GaSb superlattice focal-plane arrays for simultaneous,
colocated detection at 3 μm to 4 μm and 4 μm to 5 μm in the mid-wavelength infrared atmospheric transmission window. Integrated into a wide-field-of-view missile approach warning
system for an airborne platform, a very low number of pixel outages and cluster defects is mandatory for bispectral detector
arrays. Process refinements, intense root-cause analysis, and specific test methodologies employed at various stages during
the process have proven to be the key for yield enhancements. 相似文献
8.
Infiltration of fibrous preforms by a pure metal: Part I. Theory 总被引:4,自引:0,他引:4
A. Mortensen L. J. Masur J. A. Cornie M. C. Flemings 《Metallurgical and Materials Transactions A》1989,20(11):2535-2547
General expressions are derived to describe fluid flow and heat transfer during infiltration of fibrous preforms by a pure
metal. Analytical solutions to the problem are given for the case of unidirectional infiltration into a uniform preform of
aligned fibers under constant applied pressure. Calculations are carried out for infiltration kinetics (including total infiltrated
length) and temperature distribution, using as an example alumina fiber/aluminum composites. Limiting cases leads to very
simple expressions. Initial fiber temperatures both above and below the metal melting point are considered. In the case of
fibers at a temperature significantly below the metal melting point, it is concluded that the factor most strongly influencing
infiltration is the solidification of metal in the interfiber region. In the calculations, it is assumed that this solidification
is in the form of a uniform solid metal sheath around the fibers. Metal superheat, when present, serves to progressively remelt
the solidified sheath from the upstream end of the preform. Fiber volume fraction and initial temperature are predicted to
have a major effect on infiltration kinetics, while metal superheat exerts a relatively minor influence. When no external
heat extraction is present and a constant pressure is applied to the metal, flow through the preform continues indefinitely.
For the case of external heat extraction, flow ceases when sufficient solidification occurs to block flow.
L.J. MASUR, formerly a Graduate Student with the Department of Materials Science and Engineering, Massachusetts Institute
of Technology 相似文献
9.
10.
E.F. Masur 《Computer Methods in Applied Mechanics and Engineering》1978,14(2):237-248
The results of Prager's Note [1]of similar title are discussed and expanded. By minimizing the potential energy associated with an assumed approximate deformation field, general criteria are developed for the optimal grid spacing of bars under varying axial forces and of beams under lateral loads, both with arbitrary variation of the cross section. It is shown that Prager's tentative energy criterion is indeed confined to the special case treated in his Note, as originally conjectured by himself.For constant cross section all optimality conditions assume a simple and easily realizable form. It is shown that in this case the computed nodal displacements are exact, irrespective of the grid spacing or of the value of the potential energy. Nevertheless, optimal spacing is still useful in reducing the average error in the computed stress values. 相似文献