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Institution

Wright-Patterson Air Force Base

OtherWright-Patterson AFB, Ohio, United States
About: Wright-Patterson Air Force Base is a other organization based out in Wright-Patterson AFB, Ohio, United States. It is known for research contribution in the topics: Laser & Mach number. The organization has 5817 authors who have published 9157 publications receiving 292559 citations. The organization is also known as: Wright-Patterson AFB & FFO.


Papers
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Journal ArticleDOI
TL;DR: This paper presents a comparison of frequently used optimization algorithms based on optimality criteria to design a minimum weight structure, and presents a new iterative scheme, similar to Newton-Raphson, that can be obtained with a smaller number of analyses of the structure than with previously proposed methods.
Abstract: This paper presents a comparison of frequently used optimization algorithms based on optimality criteria to design a minimum weight structure. After summarizing the different methods, the relationship between the various algorithms is shown. They differ only in the degree of approximations made in formulating the recurrence relations to modify the design variables and to evaluate the Lagrange multipliers. A new iterative scheme, similar to Newton-Raphson, is also presented, with the equations written in such a form that it is not necessary to select the initial design vector of the unknown Lagrange multipliers. It is shown that with this scheme a minimum weight design can be obtained with a smaller number of analyses of the structure than with previously proposed methods.

104 citations

Journal ArticleDOI
TL;DR: In this article, the exciton binding energy was determined to be (4.20 \ifmmode\pm\times\else\texttimes\fi{} 0.10}^{\ensuremath{-}3}$ eV.
Abstract: The exciton energy spectrum in GaAs has been studied by photoluminescence and reflection. The photoluminescence was excited using a krypton laser (6471 \AA{}). We observed for the first time the spectra for the excited states of the free exciton in GaAs and also the spectra for the ground states in zero field and in the field range from 12 to 40 kG. The value for the exciton binding energy was determined to be (4.20 \ifmmode\pm\else\textpm\fi{} 0.3) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}3}$ eV from which the band-gap energy of 1.5195 \ifmmode\pm\else\textpm\fi{} 0.0005 eV has been deduced. The values for the Zeeman splitting factors for electron ($g$ factor) and hole ($\ensuremath{\kappa}$ parameter) were deduced from these measurements to be ${g}_{c}=\ensuremath{-}0.50\ifmmode\pm\else\textpm\fi{}0.05$ and $\ensuremath{\kappa}=1.0\ifmmode\pm\else\textpm\fi{}0.2$, respectively. A phenomenological description for the free-exciton energy spectrum in the intermediate-field regime is used to explain the experimental measurements.

104 citations

Journal ArticleDOI
TL;DR: In this article, the defect structure of polycrystalline HfO2 was investigated by measuring the oxygen partial pressure dependence of the electrical conductivity and the sample weight, and the mobility values were found to vary from 1.6 × 10 −3 to 3 × 10−4 cm2/V-sec.
Abstract: The defect structure of high-purity, polycrystalline HfO2 was investigated by measuring the oxygen partial pressure dependence of the electrical conductivity and the sample weight. From 1000° to 1500°C and above oxygen partial pressures of 10 −6, the conductivity is electronic and proportional to po21/5. The predominant defect is completely ionized hafnium vacancies. At lower oxygen partial pressures a broad shallow minimum in the lower temperature conductivity isotherms indicates the presence of an oxygen pressure independent source of electronic charge carriers. By combining the weight change and conductivity data, mobility values were found to vary from 1.6 × 10−3 to 3 × 10−4 cm2/V-sec. The activation energies for the hole mobilities were calculated to be 0.2 ev above 1300° C and 0.7 ev below this temperature.

104 citations

Journal ArticleDOI
TL;DR: In this article, an environmentally compliant replacement for chromated surface treatments, which included functionalized components to tailor the chemistry at both the aluminum oxide substrate/surface treatment interface and the surface treatment/topcoat interface, was investigated.

104 citations

Journal ArticleDOI
TL;DR: In this article, atomic simulations are used to investigate how grain boundary structure influences dislocation nucleation under uniaxial tension and compression for a specific class of symmetric tilt grain boundaries that contain the E structural unit.

103 citations


Authors

Showing all 5825 results

NameH-indexPapersCitations
John A. Rogers1771341127390
Liming Dai14178182937
Mark C. Hersam10765946813
Gareth H. McKinley9746734624
Robert E. Cohen9141232494
Michael F. Rubner8730129369
Howard E. Katz8747527991
Melvin E. Andersen8351726856
Eric A. Stach8156542589
Harry L. Anderson8039622221
Christopher K. Ober8063129517
Vladimir V. Tsukruk7948128151
David C. Look7852628666
Richard A. Vaia7632425387
Kirk S. Schanze7351219118
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20234
202211
2021279
2020298
2019290
2018272