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Direct observations of the primary state of radiation damage of ion-irradiated tungsten and platinum

Description: A brief summary was presented of all the Cornell work on the primary state of radiation damage in ion-irradiated tungsten and platinum. The primary research tool for all this research was the field-ion microscope (FIM); the FIM was ideally suited for this research because of its excellent atomic resolution and the ability to examine the interior of the specimens, as a result of the field-evaporation effect. This paper summarized, in outline form, the following items: (1) the principal experimen… more
Date: July 1, 1980
Creator: Seidman, D. N.; Current, M. I.; Pramanik, D. & Wei, C. Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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AN ESTIMATE OF THE EFFECT OF NEUTRON-ENERGY SPECTRUM ON RADIATION DAMAGE OF STEEL

Description: The postulate that the average number of lattice displacements is directly proportional to the available energy is carried one step further; it is assumed that damage to steel (particularly in regard to brittle fracture) is proportional to the number of lattice vacancies that occur. The model, although crude, permits estimation of the relative damage resulting from differences in neutron spectra. The results can be used as a rough method of correcting damage data for the effect of the neutron-e… more
Date: July 27, 1962
Creator: Claiborne, H.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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HREM imaging of single unit cell carbide precipitates in Pt-C alloys

Description: Dilute Pt-C alloys are prototypical for studying oversize carbide phase precipitation from interstitial solid solution. Earlier studies showed the essential function of quenched-in vacancies in the precipitation process. Vacancies play a dual, volume accommodation and structural role in the transformation by modifying both the habit plane spacing and stacking sequence. It was also shown how the precipitation sequence in interstitial Pt-C alloys is analogous to that in substitutional Al-Cu alloy… more
Date: July 1991
Creator: Witcomb, M. J.; Dahmen, U.; O'Keefe, M. A. & Westmacott, K. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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HREM imaging of single unit cell carbide precipitates in Pt-C alloys

Description: Dilute Pt-C alloys are prototypical for studying oversize carbide phase precipitation from interstitial solid solution. Earlier studies showed the essential function of quenched-in vacancies in the precipitation process. Vacancies play a dual, volume accommodation and structural role in the transformation by modifying both the habit plane spacing and stacking sequence. It was also shown how the precipitation sequence in interstitial Pt-C alloys is analogous to that in substitutional Al-Cu alloy… more
Date: July 1, 1991
Creator: Witcomb, M. J.; Dahmen, U.; O`Keefe, M. A. & Westmacott, K. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fundamental studies of passivity and passivity breakdown

Description: We developed and experimentally tested physical models for growth and breakdown of passive films on metal surfaces. These models are ``point defect models,`` in which the growth and breakdown are described in terms of movement of anion and cation vacancies. The work during the past 5 years resulted in: theory of growth and breakdown of passive films, theory of corrosion-resistant alloys, electronic structure of passive films, and estimation of damage functions for energy systems. Proposals are … more
Date: July 1, 1993
Creator: Macdonald, D. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Recruitment of U.S. Citizens for Vacancies in IAEA Safeguards.

Description: The International Atomic Energy Agency (IAEA) relies on its member states to assist with recruiting qualified individuals for positions within the IAEA's secretariat. It is likewise important to the U.S. government for U.S. citizens to take positions with the IAEA to contribute to its success. It is important for persons within and outside the U.S. nuclear and safeguards industries to become aware of the job opportunities available at the IAEA and to be informed of important vacancies as they a… more
Date: July 16, 2006
Creator: Occhiogrosso, D. & Pepper, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Effects of P / N in Homogeneity on CDZNTE Radiation Detectors.

Description: Spectrometer grade, room-temperature radiation detectors have been produced on Cd{sub 0.90}Zn{sub 0.10}Te grown by the low-pressure Bridgman technique. Small amount of indium has been used to compensate the uncompensated Cd vacancies for the crystals to be semi-insulating. The properties of the detectors are critically dependent on the amount of excess Te introduced into the growth melts of the Cd{sub 0.90}Zn{sub 0.10}Te crystals and the best detectors are fabricated from crystals grown with 1.… more
Date: July 8, 2002
Creator: Chu, M.; Terterian, S.; Ting, D.; James, R. B.; Szawlowski, M. & Visser, G. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Mutual passivation of group IV donors and isovalent nitrogen in diluted GaN{sub x}As{sub 1-x} alloys

Description: We demonstrate the mutual passivation of electrically active group IV donors and isovalent N atoms in the GaN{sub x}As{sub 1-x} alloy system. This phenomenon occurs through the formation of a donor-nitrogen bond in the nearest neighbor IV{sub Ga}-N{sub As} pairs. In Si doped GaInN{sub 0.017}As{sub 0.983} the electron concentration starts to decrease rapidly at an annealing temperature of 700 C from {approx} 3 x 10{sup 19}cm{sup -3} in the as-grown state to less than 10{sup 16}cm{sup -3} after a… more
Date: July 23, 2003
Creator: Yu, K.M.; Wu, J.; Walukiewicz, W.; Shan, W.; Beeman, J.; Mars, D.E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Mutual passivation effects in Si-doped diluted In{sub y}Ga{sub 1-y}As{sub 1-x}N{sub x} alloys

Description: We report systematic investigations of the mutual passivation effects of Si hydrogenic donors and isovalent nitrogen in dilute InGaAs{sub 1-x}N{sub x} alloys. Upon thermal annealing at temperatures above {approx}650 C, the Si atoms diffuse assisted by the formation and migration of Ga vacancies. When they find nitrogen atoms, they form stable Si{sub Ga}-N{sub As} nearest-neighbor pairs. As a result of the pair formation, the electrical activity of Si{sub Ga} donors is passivated. At the same ti… more
Date: July 21, 2003
Creator: Wu, J.; Yu, K.M.; Walukiewicz, W.; He, G.; Haller, E.E.; Mars, D.E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Microdefects in nitrogen doped FZ silicon revealed by Li+ drifting

Description: ULSI technology requires ultra-thin device oxides with excellent breakdown integrity. Recent studies have unveiled degraded dielectric breakdown voltage (DBV) performance of the ultra-thin oxides. These findings suggest that one source for poor oxide integrity is the incorporation of native defects from the Si substrate during oxide growth. Primary defect candidates are D defects which exist mostly in the central region of floating zone (FZ) grown Si crystals. Nitrogen (N) doping eliminates D d… more
Date: July 1, 1995
Creator: Knowlton, W. B.; Walton, J. T. & Lee, J. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ferroelectric-to-Relaxor Crossover and Oxygen Vacancy Hopping in Compositionally-Disordered Perovskites - Kta(1-X)Nb(X)O(3):Ca

Description: It is shown that lattice disorder induced by Nb and Ca substitution has a strong influence on the dielectric and relaxational properties of KTaO{sub 3}. Both substituents are believed to occupy off-center positions at the Ta site, and the difference in valence between the Ca{sup 2+} and Ta{sup 5+} ions leads to the formation of oxygen vacancies (V{sub 0}). Specifically, for a KTa{sub 1{minus}x}Nb{sub x}O{sub 3}:Ca crystal with x = 0.023 and with a 0.055 at.% Ca doping they observe: (1) a ferroe… more
Date: July 26, 1999
Creator: Samara, G. A. & Boatner, L. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluation of the intrinsic and extrinsic fracture behavior of iron aluminides

Description: Iron aluminides have excellent corrosion resistance in high-temperature oxidizing-sulfidizing environments; however, there are problems at room and medium temperatures with hydrogen embrittlement as related to exposure to moisture. In this research, a coordinated computational modeling/experimental study of mechanisms related to environmental-assisted fracture behavior of selected iron aluminides has been undertaken. The modeling and the experimental work connect at the level of coordinated und… more
Date: July 27, 1998
Creator: Cooper, B. R. & Kang, B. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The effect of Ru and Sn additions to Pt on the electrocatalysis of methanol oxidation: An in situ XAS investigation

Description: Elements such as Ru and Sn used as ad-atoms or as alloying elements are known to enhance methanol oxidation reaction (MOR). Ru, both as alloying element as well as upd deposited on Pt/C is widely acknowledged for enhancing MOR. Sn on the other hand is more controversial, with evidence indicating enhancements for MOR when present as upd layer and marginally effective when present as an alloying element. In situ XAS is used to investigate some of these inconsistencies in the electrocatalysis of M… more
Date: July 1, 1997
Creator: Mukerjee, S. & McBreen, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Lattice defects as Lotka-Volterra societies

Description: Since the early part of this century the Lotka-Volterra or predator-prey equations have been known to simulate the stability, instability, and persistent oscillations observed in many biological and ecological societies. These equations have been modified in many ways and have been used to model phenomena as varied as childhood epidemics, enzyme reactions, and conventional warfare. In the work to be described, similarities are drawn between various lattice defects and Lotka-Volterra (LV) societ… more
Date: July 1, 1995
Creator: Yost, F.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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