70,613 research outputs found
Silicon carbide semiconductor device fabrication and characterization
A number of basic building blocks i.e., rectifying and ohmic contacts, implanted junctions, MOS capacitors, pnpn diodes and devices, such as, MESFETs on both alpha and beta SiC films were fabricated and characterized. Gold forms a rectifying contact on beta SiC. Since Au contacts degrade at high temperatures, these are not considered to be suitable for high temperature device applications. However, it was possible to utilize Au contact diodes for electrically characterizing SiC films. Preliminary work indicates that sputtered Pt or Pt/Si contacts on beta SiC films are someways superior to Au contacts. Sputtered Pt layers on alpha SiC films form excellent rectifying contacts, whereas Ni layers following anneal at approximately 1050 C provide an ohmic contact. It has demonstrated that ion implantation of Al in substrates held at 550 C can be successfully employed for the fabrication of rectifying junction diodes. Feasibility of fabricating pnpn diodes and platinum gated MESFETs on alpha SiC films was also demonstrated
Temporal variations of the 100 keV trapped protons observed on satellite Explorer 26 during first half of 1965
Temporal variations of 100 keV to 1700 keV trapped protons from data recorded by scintillation counter on Explorer 26 - Jan. 29, 1965 - June 29, 196
They (Don't) Care About Education: A Counternarrative on Black Male Students' Responses to Inequitable Schooling
Focus group interviews and systematic content analysis of 304 essays written by black male undergraduates refute the dominant message that black men do not care about education. On the contrary, these students aspire to earn doctoral degrees in education despite acute understanding that the education system is stacked against them. The analysis asks what compels that dedication
Rotorcraft contingency power study
Twin helicopter engines are often sized by the power requirement of a safe mission completion after the failure of one of the two engines. This study was undertaken for NASA Lewis by General Electric Co. to evaluate the merits of special design features to provide a 2-1/2 Contingency Power rating, permitting an engine size reduction. The merits of water injection, turbine cooling airflow modulation, throttle push, and a propellant auxiliary power plant were evaluated using military Life Cycle Cost (LCC) and commercial helicopter Direct Operating Cost (DOC) merit factors in a rubber engine and a rubber aircraft scenario
Housing flexibility effects on rotor stability
Preliminary rotordynamic evaluations are performed with a housing stiffness assumption that is typically determined only after the hardware is built. In addressing rotor stability, a rigid housing assumption was shown to predict an instability at a lower spin speed than a comparable flexible housing analysis. This rigid housing assumption therefore provides a conservative estimate of the stability threshold speed. A flexible housing appears to act as an energy absorber and dissipated some of the destabilizing force. The fact that a flexible housing is usually asymmetric and considerably heavier than the rotor was related to this apparent increase in rotor stability. Rigid housing analysis is proposed as a valuable screening criteria and may save time and money in construction of elaborate housing finite element models for linear stability analyses
Research and development of high temperature resistant polymeric film forming material final summary report, 1 mar. 1961 - 17 apr. 1962
Preparation of poly-organometallosiloxane polymers from reactions between bis-dialkylamino metal derivatives and silanediol
A study of the immunity of FM discriminators to 2 pi frequency impulses
Frequency impulse response of selected FM discriminator
The Dual Formulation of Cosmic Strings and Vortices
We study four dimensional systems of global, axionic and local strings. By
using the path integral formalism, we derive the dual formulation of these
systems, where Goldstone bosons, axions and missive vector bosons are described
by antisymmetric tensor fields, and strings appear as a source for these tensor
fields. We show also how magnetic monopoles attached to local strings are
described in the dual formulation. We conclude with some remarks.Comment: 18 pages, CU-TP-588 and CERN-TH.6780/9
Forging the compact of church and state in the development of Catholic education in late nineteenth-century Scotland
As post-devolution Scotland passes the milestone of a third Scottish parliamentary election, the question of state-supported Catholic education, and the peculiar nature of the 1918 UK legislation that underpins it, is once again the subject of intense scrutiny. Emboldened by devolution and fuelled by a wave of progressive UK and European law concerned with issues of equality and diversity, opponents of separate Catholic schools have renewed their demands for the provisions of the 1918 Act to be reviewed or, indeed, abolished. With the ninetieth anniversary of the passage of the Act approaching, influential commentators from across the political spectrum have argued that its principal terms reflect the social and religious controversies of a distant era, increasingly incongruent with the inclusive culture of a multiethnic and mostly secular twenty-first century Scotland.1 The character and scale of the objections currently levelled at the continued existence of Catholic schools in Scotland suggests that reconsideration of the transactions between Church and State that led to the signing of the 1918 Act is perhaps overdue – especially as a realignment of the relationship between the two forces
seems currently to be well advanced
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