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Nonlinear optical properties of new KTiOPO sub 4 isostructures

Description: The atomic structures of the nonlinear optical materials potassium titanyl phosphate (KTiOPO{sub 4}, or KTP) and potassium titanyl arsenate (KTiOAsO{sub 4}) feature one-dimensional channels through which the potassium ions are relatively free to migrate. Ion exchange results when these materials are immersed in molten salts containing alkali metal ions. Sodium, lithium and silver all exchange readily for K{sup +} single crystals of both KTP and KTA to yield the exchanged derivatives Na{sub .95}… more
Date: January 1, 1991
Creator: Phillips, M. L. F.; Harrison, W. T. A. & Stucky, G. D.
Partner: UNT Libraries Government Documents Department
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Structural study of the high-pressure antiferroelectric phase of CsH/sub 2/PO/sub 4/

Description: A three-dimensional neutron diffraction study has been carried out on the pressure-induced antiferroelectric phase of CsH/sub 2/PO/sub 4/. At 100.7/sup 0/K and a hydrostatic pressure of 3.6 kbar, the unit cell parameters are a = 15.625(9), b = 6.254(2), c = 4.886(1) A, ..beta.. = 108.08(3)/sup 0/ and Z = 4. Atomic parameters were determined using full-matrix least-squares methods which yield final agreement indices: R(F/sup 2/) = 0.0715, R/sub w/(F/sup 2/) = 0.0807 and S = 2.13. The structure i… more
Date: January 1, 1985
Creator: Schuele, P.J. & Thomas, R.
Partner: UNT Libraries Government Documents Department
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Compendium of energy-dependent sensitivity profiles for the TRX-2 thermal lattice

Description: Energy-dependent sensitivity profiles for five responses calculated for the TRX-2 thermal lattice with the ORNL sensitivity code system FORSS are presented here both in graphical form and in SENPRO format. The responses are the multiplication factor, k/sub eff/; the ratio of epithermal-to-thermal captures in /sup 238/U, /sup 28/rho; the ratio of epithermal-to-thermal fissions in /sup 235/U, /sup 25/delta; the ratio of fissions in /sup 238/U to fissions in /sup 235/U, /sup 28/delta; and the rati… more
Date: March 1, 1978
Creator: Tomlinson, E. T.; Lucius, J. L. & Drischler, J. D.
Partner: UNT Libraries Government Documents Department
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Precipitation reactions in a beryllium-bearing stainless steel

Description: Precipitation reactions in a beryllium-bearing stainless steel alloy have been studied by TEM and electron diffraction for ageing temperatures between 400/sup 0/ and 900/sup 0/C. The nominal composition of the alloy was 38% Ni - 21% Cr - 1% Mn - 0.5% Be - Bal Fe. Specimens were solutionized for one hour at 1150/sup 0/C and water quenched. The ageing reaction was studied by hardness measurements for times between 0.5 and 16 hours. The TEM specimens dicussed herein were made from samples aged one… more
Date: January 1, 1980
Creator: Carr, M. J. & Heiple, C. R.
Partner: UNT Libraries Government Documents Department
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Applications of pulsed neutron powder diffraction to actinide elements. [Pu-Al]

Description: We have been using the technique of pulsed neutron powder diffraction to study several problems in the physics and chemistry of the actinide elements. In these elements one often encounters very complex structures resulting from polymorphic transformations presumably induced by the presence of 5f-electrons. For example, at least five distinct structures of plutonium metal are found between room temperature and its melting point of 640/sup 0/C, and two of the structures are monoclinc. The determ… more
Date: November 1, 1987
Creator: Lawson, A. C.; Richardson, J. W.; Mueller, M. H.; Lander, G. H.; Goldstone, J. A.; Williams, A. et al.
Partner: UNT Libraries Government Documents Department
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Monte Carlo analyses of TRX slightly enriched uranium-H/sub 2/O critical experiments with ENDF/B-IV and related data sets

Description: Four H/sub 2/O-moderated, slightly-enriched-uranium critical experiments were analyzed by Monte Carlo methods with ENDF/B-IV data. These were simple metal-rod lattices comprising Cross Section Evaluation Working Group thermal reactor benchmarks TRX-1 through TRX-4. Generally good agreement with experiment was obtained for calculated integral parameters: the epi-thermal/thermal ratio of U238 capture (rho/sup 28/) and of U235 fission (delta/sup 25/), the ratio of U238 capture to U235 fission (CR*… more
Date: December 1977
Creator: Hardy, J. Jr.
Partner: UNT Libraries Government Documents Department
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Structural examination of iridium-based single-crystal preparations. [AlIr; IrSi]

Description: A high-temperature crystal growth experiment produced discrete single-crystal products of AlIr and IrSi. The preparation and examination of these phases is described within. This project is part of a materials compatibility study relating to radioisotopic heat sources. These heat sources are comprised of a PuO/sub 2/ fuel pellet encapsulated in an Ir alloy containment shell. Th is introduced as an additive within the Ir to maintain ductility. Si and P are picked up inadvertently in the fuel pro… more
Date: January 1, 1985
Creator: Axler, K.M. & Roof, R.B.
Partner: UNT Libraries Government Documents Department
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Evaluation of improved light water reactor core designs. Final progress report, September 1979. LWRCD-20

Description: The work conducted under this research project has developed information which supports in all respects the U.S. position evolved under the NASAP/INFCE programs with respect to the near and intermediate term potential for ore conservation in LWRs on the once-through fuel cycle. Moreover, in the even longer term, it has been confirmed that contention by Edlund and others that tight-pitch Pu/UO/sub 2/ PWR cores can achieve conversion ratios which may allow these reactors to provide a competitive … more
Date: October 31, 1979
Partner: UNT Libraries Government Documents Department
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Structure of tris(trimethylsilylcyclopentadienyl)uranium(III), ((CH/sub 3/)/sub 3/SiC/sub 5/H/sub 43/U. [Tris(trimethylsilylcyclopentadienyl)uranium]

Description: Crystals of ((CH/sub 3/)/sub 3/SiC/sub 5/H/sub 4/)/sub 3/U are orthorhombic, Pbca, with a = 22.630(8), b = 29.177(10) and c = 8.428(3) A at 23/sup 0/C. For Z = 8 the calculated density is 1.551 g/cm/sup 3/. The structure was refined by full-matrix least-squares to a conventional R factor of 0.041 (2251 data, F/sup 2/ > 2 sigma(F/sup 2/)). The uranium atom is bonded to the three cyclopentadienyl rings in a pentahapto fashion and is in the plane of the ring centroids. The U to ring distances are … more
Date: February 1, 1986
Creator: Brennan, J.; Andersen, R. A. & Zalkin, A.
Partner: UNT Libraries Government Documents Department
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On-line model driven control of the SLC electron Damping Ring

Description: Model driven procedures have been used for control of the linac, beam transport lines and storage rings at SLAC. These procedures, based upon computer models of the machine lattice, are used for on-line calculation of the strengths of beam line components which yield desired lattice parameter values. They are also used for routine operation of the machine and for diagnosing and correcting errors of various types, as well as for aiding physicists in the acquisition and presentation of data. Succ… more
Date: March 1, 1985
Creator: Almog, I.; Jaeger, J.; Lee, M. & Woodley, M.
Partner: UNT Libraries Government Documents Department
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Preparation, properties, and some recent studies of the actinide metals

Description: The actinide elements form a unique series of metals. The variation in their physial properties combined with the varying availability of the different elements offers a challenge to the preparative scientist. This article provides a brief review of selected methods used for preparing ..mu..g to kg amounts of the actinide metals and the properties of these metals. In addition, some recent studies on selected actinide metals are discussed. 62 refs.
Date: January 1, 1985
Creator: Haire, R.G.
Partner: UNT Libraries Government Documents Department
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A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system: Part 1, Ca-Sr-Cu oxides

Description: X-ray powder patterns for the phases in the CaO-SrO-CuO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a simulated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca, Sr)O, (Ca,Sr){sub 2}CuO{sub 3}, (Ca,… more
Date: January 1, 1992
Creator: Reardon, B.J. (Alfred Univ., NY (United States)) & Hubbard, C.R. (Oak Ridge National Lab., TN (United States))
Partner: UNT Libraries Government Documents Department
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Atom-probe field-ion microscope study of the stoichiometry of ordered Ni/sub 4/Mo

Description: Atom-probe field-ion microscope analyses were performed on specimens of ordered Ni/sub 4/Mo. The (211) fundamentl and (101) superlattice planes of the body-centered tetragonal (BCT) lattice were analyzed chemically on a layer-by-layer basis. In the case of (211)/sub BCT/ fundamental planes the chemistry of each individual plane was determined as a function of depth; for eight successive (211)/sub BCT/ layers an average Mo concentration of 17.2 at. % was measured - as compared to 19.4 at. % Mo b… more
Date: May 1980
Creator: Yamamoto, Masahiko & Seidman, David N.
Partner: UNT Libraries Government Documents Department
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Magnetic Susceptibility and Proton NMR study of TiCr/sub 1/ /sub 8/H/sub x/

Description: The electronic properties of the hexagonal (C-14) and cubic (C-15) allotropes of the TiCr/sub 1/ /sub 8/+/sub 0/ /sub 1//H/sub 2/ system have been examined via magnetic susceptibility and proton NMR studies. The results indicate an increase in N(E/sub F/), the electron density of states at the Fermi level, with increasing H/M for both allotropes; the trend extends into the ..cap alpha..'-hydride phase. The results suggest a basis for thermodynamic anomalies reported for the solution of hydrogen… more
Date: January 1, 1982
Creator: Lynch, J. F.; Johnson, J. R. & Bowman, R. C., Jr.
Partner: UNT Libraries Government Documents Department
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Crystal structure of stage 1 iodine intercalated superconducting IBi sub 2 Sr sub 2 CaCu sub 2 O sub x

Description: The crystal structure of stage-1 iodine-intercalated superconducting IBi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} has been determined by transmission electron microscopy to belong to the superspace group C{sub {anti 1}1}{sub {anti 1}}{sup Pma2} with subcell lattice parameters a = 5.4 {Angstrom}, b = 5.4 {Angstrom}, c = 18.8 {Angstrom}, and a structural modulation wavelength of 26 {Angstrom}. Intercalated iodine atoms alter the atomic stacking across Bi-O layers from the staggered configuration charac… more
Date: July 1, 1991
Creator: Kijima, N.; Gronsky, R.; Xiang, X.; Vareka, W.; Zettl, A.; Corkill, J. et al.
Partner: UNT Libraries Government Documents Department
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Emerging materials systems for solar cell applications - CU/sub 2-x/Se. Final report, May 1, 1979-April 30, 1980

Description: The objective of this research program was the investigation of copper selenide (Cu/sub 2-x/Se) films as a promising potential semiconductor material for low cost, mass produced thin film photovoltaic solar cells. Major activities during this program have been the development of the semiconductor film formation process, characterization of the deposited films, calculation of the projected cell performance from theoretical analysis, and the fabrication and testing of simple cell structures. Prog… more
Date: April 1, 1980
Creator: Mickelsen, R. A.; Stewart, J. M. & Chen, W. S.
Partner: UNT Libraries Government Documents Department
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X-ray study of interfacial interactions in highly milled Sn-Ge powders

Description: We have studied possible structural changes occurring at the Sn/Ge interface of highly milled Sn/Ge composites. EXAFS and X-ray Diffraction measurements were made on mechanically milled powders having compositions ranging from 20 to 50 vol.% Sn. X-ray diffraction measurements indicate the increasing amorphization of Sn as the Sn content is decreased. EXAFS results indicate that this amorphous phase is due to the formation of an {alpha}-Sn/Ge alloy. The EXAFS from this alloy did not change signi… more
Date: January 1, 1991
Creator: Jayanetti, J.K.D.S.; Heald, S.M. & Tan, Z.
Partner: UNT Libraries Government Documents Department
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Self-Consistent Electronic Structure of Alpha-Phase Hume-Rothery Electron Compound Alloys Cu/sub C/Zn/sub 1-C/, Cu/sub C/Ga/sub 1-C/, and Cu/sub C/Ge/sub 1-C/

Description: We have performed charge self-consistent electronic structure calculations for the ..cap alpha..-phase Hume-Rothery electron compound alloys Cu/sub c/Zn/sub 1-c/, Cu/sub c/Ga/sub 1-c/, and Cu/sub c/Ge/sub 1-c/ having electron to atom ratios 1:1, 1:2, and 1:3 for each alloy series. The calculations are based on the self-consistent-field Korringa-Kohn-Rostoker coherent-potential approximation (KKR-CPA). We show results for the densities of states and Fermi surface of these alloys; the behavior of… more
Date: January 1, 1985
Creator: Stocks, G. M.; Boring, A. M.; Nicholson, D. M.; Pinski, F. J.; Johnson, D. D.; Faulkner, J. S. et al.
Partner: UNT Libraries Government Documents Department
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Energy parameters and crystal field effects in the mixed valence problem: chemically collapsed cerium

Description: Previous neutron scattering studies of the mixed valence state in rare earth systems failed to reveal the presence of crystal electric field (CEF) effects. In cases studied, the characteristic charge fluctuation energies were comparable to the expected CEF energies. A system was designed in which it is possible to systematically vary the charge fluctuation energy E/sub c/ from the regime E/sub c/ approx. ..delta.. to E/sub c/ << ..delta.., where ..delta.. is the characteristic CEF energy. Resul… more
Date: January 1, 1979
Creator: Parks, R.D.; Shapiro, S.M.; Majkrzak, C.F. & Grier, B.H.
Partner: UNT Libraries Government Documents Department
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Preparation and spectroscopic properties of three new actinide (IV) borohydrides

Description: New tetrakis-borohydrides of Pa, Np, and Pu have been synthesized. The crystal structure of Pa(BH/sub 4/)/sub 4/ is isostructural to those of Th(BH/sub 4/)/sub 4/ and U(BH/sub 4/)/sub 4/ and is of the tetragonal space group P4/sub 3/2/sub 1/2, where a = 7.53 (3) A, c = 13.22 (5) A, and Z = 4. Its calculated density is 2.57 gm-cm/sup -3/. Pa(BH/sub 4/)/sub 4/ is an orange, air-sensitive compound which is soluble in THF and sublimes at 55/sup 0/ in vacuum. Due to the thermal instabilities of Np(B… more
Date: December 1, 1979
Creator: Banks, R.H.
Partner: UNT Libraries Government Documents Department
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