Indian Institute of Science Theses & Dissertations (India)

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We present a study of the crystal field in PrNiAl, NdNiAl, ErNiAl and ErCuAl intermetallic compounds based on inelastic neutron spectroscopy. These compounds crystallize in the ZrNiAl-type hexagonal structure with an orthorhombic symmetry on rare-earth sites. The results are compared with the specific-heat data, and the lower parts of the crystal-field energy-level schemes are determined. (orig.)

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We have investigated the superconducting and metallurgical properties of the ternary compounds RPd_2Si_2 and RRh_2Si_2 with R = Y, La, and Lu. All RPd_2Si_2 compounds and LaRh_2Si_2 were found to be type-I superconductors below 1 K. A detailed metallurgical analysis shows that segregation of second phases can easily mask the intrinsic (stoichiometric ratio 1:2:2) intermetallic-compound properties. Two sample-preparation techniques, viz., single crystals and off-stoichiometry, were utilized to establish where bulk superconductivity occurs. The type-I behavior of these compounds is explained with an analogous model as is used for the heavy-fermion superconductors CeCu_2Si_2 and URu_2Si_2.

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... The Effect of the Temperature to Which the Material is Heated on the Process of Formation of Intermetallic Compounds in Magnetic Pulse Welding,. ...

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Many important advances in the physics of strongly correlated electron systems have been driven by the development of new materials: for instance the filled skutterudites Formula Not Shown ( Formula Not Shown metal, alkaline earth, lanthanide, or actinide; Formula Not Shown , Ru, or Os; Formula Not Shown , As, or Sb), certain lanthanide and actinide intermetallic compounds such as Formula Not Shown and Formula Not Shown ( Formula Not Shown , Rh, or Ir), and layered oxypnictides and related materials. These types of complex multinary d- and f-electron compounds have proven to be a vast reservoir of novel strongly correlated electron ground states and phenomena. In these materials, the occurrence of such a wide range of ground states and phenomena arises from a delicate interplay between com...

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Ternary R_2TSi_3 intermetallic compounds (R=Rare Earth, T=Transition Metal) with hexagonal AlB_2-type crystallographic structure are known because of their interesting physical properties. Pr_2PdSi_3 single crystals were grown by a vertical floating zone method. The compound exhibits congruent melting behavior at a liquidus temperature of about 1770 C. Single crystalline samples show a huge anisotropy at low temperatures due to the crystal electric field effect and order antiferromagnetically below the Neel temperature T_N=2.17 K. This value approximately obeys the linear de Gennes scaling for this class of compounds. The [001] orientation was identified as the magnetic easy axis at room temperature. At lower temperature (#approx#20 K) magnetic easy and hard axes interchange with each other. Two additional magnetic phase transitions were observed at temperatures below 1 K.

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... magnetic susceptibility magnetization monocrystals neutron diffraction

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Many important advances in the physics of strongly correlated electron systems have been driven by the development of new materials: for instance the filled skutterudites MT4X12 (M=alkali metal, alkaline earth, lanthanide, or actinide; T=Fe, Ru, or Os; X=P, As, or Sb), certain lanthanide and actinide intermetallic compounds such as URu2-xRexSi2 and CeTIn5 (T=Co, Rh, or Ir), and layered oxypnictides and related materials. These types of complex multinary d- and f-electron compounds have proven to be a vast reservoir of novel strongly correlated electron ground states and phenomena. In these materials, the occurrence of such a wide range of ground states and phenomena arises from a delicate interplay between competing interactions that can be tuned by partial or complete substitution of one element for another, as well as the application of pressure, and magnetic fields, resulting in rich and complex ...

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The energy bands and the nature of the conduction electrons have been studied for three intermetallic compounds of dysprosium. e.g., DyZn, DyCu and DyRh, following the augmented plane wave method. Density of states results are given and have implications for the stability of the structure of the intermetallic compounds of dysprosium. The charge densities and the number of conduction electrons inside and outside the APW spheres in each of these compounds are calculated; it is shown that the character of conduction electrons within the Dy APW sphere is principally of d type for all the compounds. The consequence of the predominance of d electron in the conduction bands on the various physical parameters is discussed. (author).

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The impulse method has been used to study "9"3Nb (nuclear quadrupole resonance (NQR) parameters quadrupole connection constant, spin-lattice and spin-spin relaxation times) in binary intermetallic compounds of Nb_3X (x=Al, Ga, Ge, Sn, Pt, Os, Ir, Sb) and in some ternary phases on the basis of the Nb_3Al compound. The discussion on experimental data obtained is carried out in approximation of a tight connection for d-electrons.

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Substantial roles of precipitates such as Zr-Fe-Cr type intermetallic compounds on uniform corrosion and hydrogen pickup of zirconium alloys in pure water autoclave tests were investigated from an electrochemical point of view. This paper describes the roles on corrosion. A corrosion test on precipitate-containing and precipitate-free materials made from pure zirconium and a small quantity of iron and chromium, rest potential measurements on an intermetallic compound of Zr(FeCr){sub 2} and zirconium matrix, and a galvanic coupling test of those were performed. Results showed that corrosion behavior of zirconium alloys could be attributed to the electrochemical properties of intermetallic compounds precipitated in each alloy. Namely, the cathodic and anodic polarization characteristics were associated with anodic protection provided by the precipitates on the ...

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The thermodynamics of the Sr-Si system is of fundamental importance for the understanding of eutectic modification of Al-Si alloys. At the same time, strontium silicides have recently been found to have potential applications in electronic devices. Renewed research efforts have led to a re-evaluation of the phase equilibria in this system, resulting in the discovery of previously undetected stable intermetallic compounds. In this work, we investigate the finite temperature thermodynamic properties of the stable (and metastable) Sr-Si intermetallics. The vibrational properties of the intermetallic compounds are calculated within harmonic theory, with quasi-harmonic corrections to account for the effects of thermal expansion. The total free energies of the compounds are computed considering vibrational and electronic contributions, as well as weak anharmonic ...

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The theoretical treatment of the relation between the critical angle of planar channeling and the characteristics of crystal lattice defects is carried out. The predictions are made about some typical forms of the critical angle dependence on the mean-square static displacement produced by defects, and then these predictions are detailed for the cases of homogeneous disordering, spherical clusters of point defects and dislocation loops. Analytical results are supported by the exact computer calculations for the defects in the intermetallic A-15 compounds.

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In this thesis the results are described of an investigation into the radiationless transfer of electronic excitation energies in various Eu"3"+ and Tb"3"+ compounds, which show structural peculiarities in the rare-earth sublattice. These peculiarities are an one-dimensional sublattice as well as two different crystallographic locations for the rare-earth ion. 154 refs.; 43 figs.; 12 tabs.

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Hie synthesis of diverse biologically important compounds, under condi- tions which existed on the earth in the initial period of its evolution, ha; ...

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An intermetallic compound Sm[sub 2]Fe[sub 17]N[sub x] was synthesized by plasma nitriding of Sm[sub 2]Fe[sub 17] in a stream of N[sub 2]-H[sub 2] mixed gas. The reaction proceeded at a lower temperature (around 423 K) than that of the conventional thermal technique, but not at room temperature. This is discussed on the basis of the difference between the reaction mechanisms of plasma and thermal nitridings. (orig.)

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In this paper we studied the behavior of commercially pure niobium immersed in molten aluminum. The experiments were carried out 800 and 900 deg C during 2 to 128 hours. Chemical and metallographic analyses, as well as microhardness measurements of the niobium specimens were accomplished. An increase of niobium content in the aluminum bath with time was observed. Metallographic observations revealed the formation of Nb Al{sub 3} external intermetallic compound. During dissolution, fragments of this compound settled at the bottom of the crucible. This behaviour was also observed at 900 deg C, nevertheless with higher intensity. (author) 10 refs., 5 figs., 3 tabs.

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The paramagnetic susceptibilities of all the RCo_2 compounds for which measurements are available are found to obey a Curie-Weiss law consistent with the modified indirect exchange model. The rare-earth ions are in a well defined tripositive valence state. Paramagnetic moments and paramagnetic Curie temperatures are obtained for these materials for the first time. The paramagnetic moments of these materials are changed from their free-ion values by the effects of itinerant electron polarisation, an effect which is particularly large for SmCo_2 whose paramagnetic moment is almost three times greater than the free-ion value. The modified indirect exchange model is found to be able to give a full description of the magnitude of the rare-earth, cobalt and diffuse moments in polarised neutron experiments. The band structures of the light RCo_2 compounds are found to be distinctly different to those of the ...

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For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO2, PrO2), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two sha...

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Kinetics of decomposition of gallium and alkali metal intermetallic compounds in the systems LiGa-LiOH, LiGa-NaOH and LiGa-KON was studied in the temperature range of 40-80 deg C. It was ascertained that increase in temperature gives rise to increase in decomposition rate, whereas increase in hydroxide concentration involves the reaction deceleration. An assumption was made that the decomposition occurs with superimposing of two mechanisms, i.e. chemical and electrochemical decomposition. Basic kinetic characteristics of the process were determined - decomposition rate constant and current density

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Intermetallic compounds are regarded as highly promising for applications as high temperature structural materials. However, recent studies have demonstrated that a number of ordered alloys exhibit environmental embrittlement when tested in various environments at ambient temperature. When exposed to hydrogen gas or electrolytically charged with hydrogen, a significant ductility loss has been reported. The reaction of water vapor with reactive elements in the crack tip results in the generation of atomic hydrogen which diffuses from the surface to the interior and causes embrittlement. In this paper, the authors try to analyze the sensitivity of hydrogen embrittlement of ordered alloys based upon energetical considerations.

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Intermetallic compounds based on the Al-Co system were synthesized by solid state method - mechanical alloying and their properties were investigated using XRD, SEM, and DSC. The powder was used to make new targets of irradiation for gamma sources in order to enhance the specific activity and to reduce the consumption of material. The intermetallic compound AlCo was formed in the first 4 hours of milling. After 8 hours of milling the medium size of crystallites were of 5.58 nm. This value decreases with the increase of milling time up to 3 nm, corresponding to the 28 hours of grinding. There was calculated and plotted the Gibbs function, #DELTA#_f"0, for the reaction of formation AlCo and Al_3Co from the Al-Co system. It had negative values over the entire range of temperatures for both investigated compounds. After 28 hours milling a phase composition was obtained as follows: 0.2% ...

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For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO{sub 2}, PrO{sub 2}), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two shapes: small cubic (oxide) and large plate-like (tetragonal) structures. The ...

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The influence of irradiation with 2.6 MeV H and He nuclei on the superconducting properties (critical temperature Tsub(c), critical current Isub(c)) of the intermetallic compound Nb_3Sn was studied. Irradiation led to a significant lowering of Tsub(c), while Isub(c) is increasing with the radiation dose. This is assumed to be due to the formation of active pinning centres in the lattice. There is a fast drop of Isub(c) after a peak value has been reached. Annealing of the samples (600-1,000"0C) led to an almost complete recovery of the initial value of Tsub(c). X-ray diffraction showed that irradiation causes considerable distortions of the lattice while the A15 crystal structure is retained. The causes of the radiation effects related to structural defects are discussed. (GSCH).

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The concept of nanocrystal conversion chemistry, which involves the use of pre-formed nanoparticles as templates for chemical transformation into derivative solids, has emerged as a powerful approach for designing the synthesis of complex nanocrystalline solids. The general strategy exploits established synthetic capabilities in simple nanocrystal systems and uses these nanocrystals as templates that help to define the composition, crystal structure, and morphology of product nanocrystals. This article highlights key examples of 'conversion chemistry' approaches to the synthesis of nanocrystalline solids using a variety of techniques, including galvanic replacement, diffusion, oxidation, and ion exchange. The discussion is organized according to classes of solids, highlighting the diverse target systems that are accessible using similar chemical concepts: metals, oxides, chalcogenides, phosphides, alloys, intermetallic compounds, sulfides, and ...

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In case of airplane engine, technical development like increase of temperature at the turbine entrance or high speed rotation with a purpose of thrust up, and reduction of structural part single substance mass or reduction of number of parts in order to achieve lightness and so forth, has been promoted in order to improve the performance that is evaluated by thrust weight ratio (thrust/weight). Accordingly, research and development of high heat resistance, high strength, lightness and so forth of each material of the parts are in demand. As a representative material corresponding to such demand, L10 type {nu}-TiAl intermetallic compound which is light and has improved high temperature strength properties is paid attention and its development is promotes. The authors were successful for the first time in the world to manufacture composite material with CVD type SiC fiber that was difficult so far by using TiAl-Cr alloy having super plasticity at ...

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The DC magnetic susceptibility of the REBa_2F_7 compounds was measured by a SQUID magnetometer in the temperature range 5-300 K. Except for Eu, the other compounds show either Curie law or Curie-Weiss law with relatively small values of paramagnetic Curie temperature, #theta#_p, with effective magnetic moments in the range expected of electronic ground state of the trivalent rare earth ion with appropriate J value. The behaviour of Eu is complex. (orig.).

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Magnetic properties of polycrystalline samples of RPd/sub 2/Si compounds (R = Gd, Tb, Dy, Ho and Er) are presented. The Gd and Tb based compounds are antiferromagnetic with Neel temperatures of 13.5 and 21 K respectively. For both compounds a metamagnetic transition is observed in low field. Moreover, in TbPd/sub 2/Si a transition between two different antiferromagnetic phases is observed at 8.5 K. The Dy, Ho and Er based compounds are ferromagnetic with Curie temperatures of 9, 3.5 ad 2.8 K respectively. The observed properties result from indirect exchange interactions and crystal field effects acting on rare earth ions which lie in a very low symmetry site.

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The temperature dependence of the average magnetization direction in an Fe_8_0B_2_0 glassy alloy (METGLAS 2605) is investigated by Moessbauer spectroscopy. Moessbauer spectra were recorded between 77 K and 363 K using a conventional constant-acceleration Moessbauer spectrometer with 10 mCi "5"7Co in Pd source. The direction of the easy magnetization is found to be strongly terperature dependent and the out-of-plane component turned to be unusually large. Comparing the magnetic moments some similarities between the electronic structure of the glassy alloy and the Fe_2B and FeB intermetallic compounds are established and discussed. (Sz.N.Z.).

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Visualization of a liquid metal flow and image processing methods to measure the vector field are carried out by real-time neutron radiography. The JRR-3M real-time thermal neutron radiography facility in the Japan Atomic Energy Research Institute was used. Lead-bismuth eutectic was used as a working fluid. Particles made from a gold-cadmium intermetallic compound (AuCd{sub 3}) were used as the tracer for the visualization. The flow vector field was obtained by image processing methods. It was shown that the liquid metal flow vector field was obtainable by real-time neutron radiography when the attenuation of neutron rays due to the liquid metal was less than l/e and the particle size of the tracer was larger than one image element size digitized for the image processing. (orig.).

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Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

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The luminescence spectra of trivalent europium ion embedded in various rare earth chromates were analysed. The spectroscopic data in most of chromates are in agreement with the structural determination but for some others the discrepancy between two methods is underlined. Energy level schemes were deducted from the experimental emission spectra and the crystal field simulation has been performed. The maximum splitting of the "7F_1 manifold of the Eu"3"+ ion as a function of N_v, the so-called crystal field strength parameter, is given. This allows us to classify the compounds according to their crystal field extent. (author)

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The inverse susceptibilities of the monopnictides and monochalcogenides of the light rare earths plotted vs. temperature flatten off at high temperatures. This behaviour is well explained by van Vleck paramagnetism of the excited states of the multiplet. For almost all actinide pnictides and chalcogenides a similar flattening-off is observed. Since spin orbit coupling is much stronger than in the light rare earth compounds an analogous interpretation is not possible. Susceptibility curves for uranium compounds can be fitted by adding a temperature dependent enhanced Pauli paramagnetism to the Curie-Weiss term (modified Curie-Weiss law). The high temperature susceptibility behaviour of neptunium compounds is very similar to uranium compounds i.e. an appreciable deviation from the Curie-Weiss law is only visible for the chalcogenides. The plutonium chalcogenides ...

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The temperature dependence of T/sub 1/ spin-lattice relaxation time on /sup 51/V, /sup 69/Ga, /sup 71/Ga and Knight shift on /sup 51/V and /sup 29/Si nuclei in polycrystalline V/sub 3/Si, V/sub 3/Ga, V/sub 3/Ge and in the monocrystal V/sub 3/Si in normal state is investigated. For V/sub 3/Si and V/sub 3/Ga a rapid growth (T/sub 1/T)/sup -1/ is observed with temperature decrease while for V/sub 3/Ge the maximum (T/sub 1/T)/sup -1/ at T approximately equal to 60 K has been found. The temperature dependence peculiarities have been discussed on the basis of theoretical models available and zone structure calculations for A-15 compounds. The T/sub 1/ anisotropy and possibility of its experimental discovery are considered. Anisotropic contribution in (T/sub 1/T)/sup -1/ and contributions of d states of different symmetries into the electron state density at the Fermi level are estimated for V/sub 3/Si from T/sub 1/ measurements.

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Stripping Voltammetry (SV) at microelectrodes has gained increased interest in the analysis of aqueous solutions due to its ability to analyze low concentrations (ppb) of electroactive metallic species in solution. Existing integrated circuit (IC) technology allows the inexpensive fabrication of microelectrodes with dimensions on the order of microns and with a high degree of uniformity and reproducibility. Additional circuitry, both multiplexing and signal conditioning, can be placed directly onto the sensor offering increased sensitivity and flexibility. Multi-element electrochemical sensors containing arrays of Pt, Au, and Ag electrodes and capable of individual measurement through built-in multiplexing or simultaneous measurement at the appropriate potential ranges for each individual electrode were fabricated using existing 2 micron IC technology. Results of simultaneous measurements of low concentrations of Cd, Pb, Cu, As, and Hg in solution indicate that interferences due to ...

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The magnetic properties of polycrystalline and single crystalline rare earth transition metal silicides Gd_xLa_1_-_xMSi (M =Fe, Co) were investigated. Magnetic measurements have been made in static magnetic fields up to 13 kOe and in pulsed magnetic fields up to 250 kOe in the temperature range from 4.2 to 350 K. The magnetic susceptibility in the paramagnetic state of all the investigated compounds obeys the Curie-Weiss law except for LaFeSi and LaCoSi. Increase of the La content in Gd_xLa_1_-_xFeSi compounds leads to a decrease of the Curie and Neel temperatures, which can be explained by a decrease of positive exchange interactions. (orig.).

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New rare earth metal rich cadmium compounds RE_4CoCd and RE_4RhCd (RE = Tb, Dy, Ho) were prepared by high-frequency melting of the elements in sealed tantalum tubes. The samples were studied by x-ray powder and single-crystal diffraction. All the compounds crystallize with Gd_4RhIn-type structure, with space group F4-bar3m. The structures are built up from rigid three-dimensional networks of condensed, cobalt (rhodium) centred trigonal RE_6 prisms. The voids left by these networks are filled by Cd_4 cluster units and the coordination number 14 polyhedra of the RE1 atoms. The terbium and dysprosium compounds in both series undergo antiferromagnetic ordering, whereas the holmium compounds exhibit ferromagnetic ordering. The magnetic ordering in these compounds is characterized by broad peaks around the transition temperatures. The results of detailed ...

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The crystal structure of borophosphates ABPO{sub 5} (A = alkaline earth or Pb) was resolved on a polycrystalline sample using the Rietveld method. The x-ray diffraction patterns data show that ABPO{sub 5} crystallize in a centrosymmetric space group P3{sub 1}21 and their structure is related to the borogermanates REBGeO{sub 5} with a stillwellite-type structure. Pr{sup 3+} ion was used as a local structural probe to corroborate the structural resolution results. Absorption and fluorescence spectra of A{sub 1-x}Pr{sub x}BP{sub 1-x}Ge{sub x}O{sub 5} (A alkaline earth or Pb; x = 0.05) have been investigated at different temperatures. At 9 K the 3{sup H}{sub 4}{yields}{sup 3}P{sub 0} transition of trivalent praseodymium ion (4f{sup 2} configuration) is observed as a single line. This indicates a unique crystallographic site for the rare earth ion in these compounds replacing the divalent cation. Energy ...

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The electronic band structure, transport properties, and lattice dynamics in AuX_2 (X = Al, Ga and In) under high pressure have been extensively studied with full potential linearized augmented plane wave and pseudopotential plane wave methods. The theoretical results for the electronic band structure and Fermi surface reveal pressure-induced electronic topological transitions (ETTs) in AuGa_2 and AuIn_2, while they are absent in AuAl_2, in excellent agreement with the experimental observations. Moreover, calculations of the transport properties at different pressures reveal subtle changes in the band structure close to the Fermi surface of the three intermetallic compounds. It is clear that the anomalies in transport properties are due to ETTs. Interestingly, a pressure-induced soft transverse acoustic (TA) phonon mode is identified only in AuGa_2. The TA phonon instability at the Brillouin zone boundary L point might be responsible for the ...

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Application of electromagnetic forces to materials processing, so-called {open_quotes}electromagnetic processing of materials (EPM){close_quotes} has been recognized as cutting edge technology, especially in the fields of steelmaking and advanced materials processing in Japan. The history of EPM in Japan is mentioned and the background to promote EPM is described. The current status of research and development of EPM is shown briefly introducing several examples. Regarding the application of high-frequency magnetic field, two topics are dealt with. The first is the improvement of the surface quality of cast steel where an alternating magnetic field is imposed on the molten steel from the outside of the mold, and the second is the induction cold crucible where a considerably large amount of molten intermetallic compound is levitated. Examples of the application of DC magnetic field are the control of molten steel flow in a mold and the ...

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Substantial roles of precipitates such as Zr-Fe-Cr type intermetallic compounds on uniform corrosion and hydrogen pickup of zirconium alloys in pure water autoclave tests were investigated from an electrochemical point of view. In the previous paper, corrosion mechanism was elucidated by the anodic protection-precipitates degradation model. This paper describes the roles on hydrogen pickup. 633 K pure water autoclave test was performed on high purity zirconium, Zr-0.2Fe, Zr-0.2Cr, and Zr-0.1Fe-0.1Cr alloys. Hydrogen analysis after the corrosion test showed that hydrogen pickup ratio of Zr-0.2Fe alloy was about 80%. It was much higher than about 30% of pure Zr and about 10% of both Zr-0.2Cr and Zr-0.1Fe-0.1Cr alloys. Larger hydrogen content was introduced into Zr-0.2Fe alloy than the other ones by the cathodic hydrogen charging under coulombic equivalence. The precipitates at metal-oxide interface could act not only as cathodic sites in the ...

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The crystal structure, lattice strain due to the antiferromagnetic ordering, and magnetic form factor in the itinerant 5f compounds UTGa_5 (T=Ni, Pd, Pt) have been studied by neutron scattering. High-resolution powder diffraction revealed that the tetragonality of the U-Ga layers increases down to the series of the transition metal element T. The integrated intensities of the antiferromagnetic reflections can be well explained with the Neel-type structure for UNiGa_5, whereas UPtGa_5 has the antiferromagnetic stacking of the ferromagnetically ordered uranium moments in the c plane. In both compounds the uranium moments orient along the c axis with moments of 0.75(5) and 0.32(5) #mu#_B for UNiGa_5 and UPtGa_5, respectively. No magnetic peak could be observed in the powder diffraction pattern of UPdGa_5 due to the small magnetic moment less than the experimental sensitivity. The orbital contributions in the magnetic form factor are reduced from ...

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DC resistivity, dc magnetization, and specific heat of eight Sc/sub 5/Co/sub 4/Ge/sub 10/-type crystal structure compounds R/sub 5/T/sub 4/Ge/sub 10/ for R = Dy, Ho, Er, Tm, and T = Rh and Ir are presented. The resistivity, single crystal magnetization, and specific heat results show that in all those compounds, the magnetic moments order antiferromagnetically in the c direction at low temperature. However, in the Er and Tm compounds, the magnetizations along x-y hard directions do not show any anomalies above 2.0 K. This suggests that the ordered Er and Tm ions, which have positive quadrupole coefficients ..cap alpha../sub j/, interact with a crystal field that has an electronic potential valley along the c axis. The fitting of the hard axis magnetizations to Curie-Weiss law suggests that the resulting antiferromagnetic-like theta reflects the strength of the crystal field torque on the magnetic moments rather than the ...

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Automated Transport. Not Studied in Detail. Earth's Neighborhood. Simplified Infrastructure. Mars. Earth-. Moon L. 1. Gateway. Moon. Earth-Sun L. 2. Science ...

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A technique of producing radioactive isotopes of rare earth elements (r.e.e.) and carrier free "2"4"2Am is suggested. The technique makes use of ''sandwich'' phthalocya=- nine complexes of r.e.e. and americium placed on sorbent. This is a new type of r.e.e. compounds and actinides (C_3_2H_1_6N_8)_2M (M is a metal ion) which are thermally, radiationally and chemically stable, dissolve well in some organic solvents and do not dissolve in water. Radiation and chemically stable activated carbon is used as a sorbent carrier. After irradiation the target is treated by a weakly acid solution or complex-former solution. Radioactive atoms formed due to (n, #gamma#)-reaction and desoleting the complex because of recoil transfer into the solution. When irradiating in the flux of 10"1"3 neutr./cm"2 x s for 1 hour it is possible to produce radioactive isotopes with the yield from 20 to 90%, for example "1"6"0Tb, "1"6"6Ho with enrichment factor > 100 and ...

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A diffuse-reflectance capability for the Fourier transform infrared spectrometer at the Y-12 Plant Laboratory has been implemented. A sample cell with a 25 to 400/sup 0/C temperature-controlled sample stage and an ultrahigh-vacuum-to-atmospheric pressure gas-handling capability has been developed. Absorbance of light from the spectrometer beam, resulting from the beam being scattered from a powder sample, can be measured. This capability of detecting molecular species on and in powders is to be used to study chemisorption on actinide and rare-earth metals, alloys, and compounds. Cell design is described along with experiments demonstrating its performance in detecting moisture absorption on uranium oxide, moisture and carbon dioxide absorption on the lithium hydride/hydroxide system, and carbon dioxide absorption on potassium borohydride. 13 figures.

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The magnetic ordering temperature of some rare-earth-based heavy-fermion compounds is strongly pressure dependent and can be completely suppressed at a critical pressure, p_c, making way for novel correlated electron states close to this quantum critical point. We have studied the clean heavy-fermion antiferromagnets CePd_2Si_2 and CeIn_3 in a series of resistivity measurements at high pressures up to 3.2 GPa and down to temperatures in the mK region. In both materials, superconductivity appears in a small window of a few tenths of a GPa on either side of p_c. We present detailed measurements of the superconducting and magnetic temperature-pressure phase diagram, which indicate that superconductivity in these materials is enhanced, rather than suppressed, by the closeness to magnetic order. (author)

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The high-temperature enthalpy increments of the phosphates La{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3}, Nd{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3}, Eu{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} and Lu{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} have been measured by high-temperature drop calorimetry in the temperature range 484.5-1090.7 K. From these results the heat capacity of the studied compounds has been derived.

International Nuclear Information System (INIS)

We succeeded in synthesizing a new cubic intermetallic compound PrCu_4Ag in a fcc structure. Measurements of X-ray diffraction, magnetic susceptibility, magnetization, specific heat, electrical resistivity, thermal expansion, and elastic constants have been performed on single crystals of PrCu_4Ag. A maximum value of #chi#(T) with a corresponding peak in C(T) suggests that an antiferromagnetic phase transition occurs at T_N=2.4 K, where a sudden decrease in #rho#_4_f(T) and a sharp peak in the thermal expansion coefficient #alpha#(T) were observed. Characteristic Curie-type softening was observed in the temperature dependence of the transverse mode for (C_1_1 - C_1_2)/2 and C_4_4 from 70 K down to T_N, which implies that the crystalline electric field (CEF) ground state is the magnetic triplet #GAMMA#_5. The anisotropic properties in M(T,H) and C(T,H) are studied when the external magnetic field is applied in the <100>, <110>, and ...

International Nuclear Information System (INIS)

The electrochemical behavior of some zirconium alloys including Zry-2 with various #SIGMA#Ai from 2.5 x 10"-"2"0 to 1.2 x 10"-"1"7 (h), modified Zry-2 with iron contents of 0.15, 0.25, and 0.5%, and standard Zry-4 was studied by measuring anodic polarization curves in sulfuric acid solution. The results of these electrochemical tests were compared with those of steam autoclave tests. In Zry-2, the current peak was observed at 1250 mV (versus SCE) on the anodic polarization curve, and this peak area increased with #SIGMA#Ai and with the size of secondary precipitates. Also, this peak was closely correlated with nodular corrosion resistance as expected from the above results. As iron contents in modified Zry-2 increased, the current peak at 1,250 mV decreased and a new peak at 1,900 mV appeared. The former peak disappeared and the latter peak increased further at 0.5% iron. In Zry-4, the current peak was observed at 1,900 mV, but not at 1,250 mV, and this behavior was the same as that of ...

International Nuclear Information System (INIS)

Alloying elements such as Fe and Cr are generally considered to be effective even in small quantities for corrosion resistance of Zircaloy-4. The maximum total solubility of Fe + Cr in a Zr-Sn matrix has been reported to be very low. Therefore, most of these elements are observed in the form of ternary Zr-Fe-Cr-type precipitates. To clarify the effects of precipitates on corrosion property, Zr-1.3 Sn-(Fe,Cr) alloys containing Fe + Cr from 45 up to 180 ppm (the Fe to Cr ratio is about 2) were melted from pure zirconium (X-bar Zr and EB-Zr) and pure alloying elements. They were subjected to corrosion testing in 633 K water and microstructural analysis. It was found that precipitate-free materials showed much larger weight gains than precipitate-containing materials even at the same alloy compositions. Subsequently, a corrosion test on the precipitate-free material galvanically coupled with a noble intermetallic compound of ...

Energy Technology Data Exchange (ETDEWEB)

The rare-earth based nickelates RNiO{sub 3} (R=Pr, Nd, Sm, Eu, and Pr{sub 1-x}La{sub x}, 0{<=}x{<=}0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R{sup 3+} site within the electronic ground-state J multiplet (for R=Pr, Nd, and Pr{sub 1-x}La{sub x}) as well as within the two lowest-lying J multiplets (for R=Sm and Eu) were directly observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments. Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge transfer from the observed variation of the CEF ...

International Nuclear Information System (INIS)

The aim of this work is to understand the reasons for the selectivity shown in the complexation by unsaturated heteropolyanions (HPA) of actinides (An) which are oxidized to the number +IV. Different studies have been carried out, both in solution and in solid state, on P_2W_1_7O_6_1"1"0"- and its complexes with Zn"2"+, UO_2"2"+, Ce"4"+, Th"4"+ and U"4"+ to characterize the nature of the complexation site offered to the cation. Among the actinides(IV), the U"4"+ ion has been selected due to its singular spectroscopic and magnetic properties. An initial series of studies, in solution, using NMR"3"1P has thus enabled us to characterize these complexes and to compare them to those formed with the complexing agent PW_1_1O_3_9"8"-. This body of data allows to identify an identical complexation site for both ligands. An analysis of the NMR"3"1P spectrum of U(P_2W_1_7O_6_1)_2"1"6"- has shown a plane of symmetry passing through the actinide and enables us to confirm the hypothesis of a ...

British Library Electronic Table of Contents (United Kingdom)

In this paper we describe a Ni-Sn intermetallic material obtained via template electroplating synthesis. The structure and the morphology of this material are investigated by X ray diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. We demonstrate that Ni-Sn behaves as a sub-micrometric electrode showing a favourable response when cycled in a lithium cell. The results here reported suggest that the template electroplating is a promising synthetic approach that can lead to an optimized structure and morphology of the Ni-Sn electrode, such as to confer it a role of a high capacity anode in advanced lithium ion batteries.

Science.gov (United States)

Feb 25, 2008 ... In the two Landsat scenes shown above, the pattern of deforestation can be clearly discerned. Deep green in these images shows lush ...

Science.gov (United States)

films and cylinders of rare earth doped yttrium aluminum garnets. ... We knew that yttrium aluminum garnet (YAG) could be doped with ...

Science.gov (United States)

... of this material is, however, outside the currently approved earth fill materials collection area ... fill material suitable for its intended use. The currently approved site contains material that is ...

Energy Technology Data Exchange (ETDEWEB)

This patent describes the vapor phase catalytic dehydrogenation of a C/sub 2/-C/sub 4/ paraffin by contacting the paraffin with a spinel of the formula A/sup III/V/sub 2-x//sup III/C/sub x//sup III/O/sub 4/, formula (1) or a crystalline perovskite of the formula D/sup III/V/sub 1-y//sup III/C/sub y//sup III/O/sub 3/, formula (2) where A is one or more of Mg, Zn, Mn, Fe, Co, Ni, Cu and Cd; D is oone of more of Y, the rare earths and Bi; C is one or more of Al, Ga, Cr, Fe and Co, x is zero to < 1.9, and y is zero to < 0.9, which spinel or perovskite is made by a process which comprises (1) reducing a pentavalent vanadium oxidic compound to substantially the V/sup 111/ state by heating at 100/sup 0/C or less an aqueous medium slurry of solution of the pentavalent compound containing a reducing agent selected from hydrazine and a hydrocarbylhydrazine, (2) providing in the aqueous medium ether before, during or after the ...

International Nuclear Information System (INIS)

Various compositions of Y(Ta,Nb)O4:Eu3+,Tb3+ with different Nb and activator concentrations have been investigated under UV and VUV excitation. Some compounds with very strong emission under VUV excitation were found. Such phosphors could be proposed as very good emissive materials for Displays and Lightings. The growing interest in luminescence spectroscopy of rare earth ions in the vacuum ultraviolet (VUV) and the visible (VIS) spectral range is due to industrial demands for new applications. YTaO4 and YNbO4 phosphors are a perspective class of efficient materials that are generally used in X-ray intensifying screens. These phosphors exhibit satisfying luminescence whenever excited by UV light, cathode radiation or X ray. However, to our knowledge, no work has been published on the VUV-excited luminescence for Eu3+ and Tb3+ double activated yttrium niobate and yttrium tantalate based phosphors. In this paper, the VUV-UV PL and PLE spectra of ...

Energy Technology Data Exchange (ETDEWEB)

The electrogeometric model cannot consider the influence of some parameters on the screening of the wire conductor of the H.V. lines. For analysing the influence of these parameters (the conductor potential, the influence of the distance from phase conductor to earth wire, the influence of the reducing factor of the striking earth distance, the earth slope, etc.), the Monte Carlo method is preferable. The influence of the earth slope on the screening effect of the wire conductor for different conditions is presented in this paper. (author)

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Science.gov (United States)

The title compounds were prepared by arc-melting of the elemental components. Whereas NdPdSi and SmPdSi are already present after the arc-melting, alpha-GdPdSi and alpha-TbPdSi are formed only during the annealing at 800 degC. The four compounds crystallize with the recently reported alpha-YbAuGe type structure, which was refined for alpha-GdPdSi: Pnma, a=2108.0(4) pm, b=433.9(1) pm, c=745.6(1) pm, Z=12, R=0.026 for 1447 structure factors and 62 variable parameters. The lanthanoid atoms are situated between two-dimensionally infinite nets of condensed, puckered hexagons formed by alternating palladium and silicon atoms, with Pd-Si distances varying between 251 and 262 pm. In the third dimension these nets are linked via weak Pd-Pd (300 pm), Pd-Si (283 pm), and Si-Si bonds (261 pm). The refinements of the occupancy parameters suggested that ca. 2% of the palladium sites are occupied by silicon atoms and vice versa. The structural relationships ...

Energy Technology Data Exchange (ETDEWEB)

The photoluminescence spectra of the lanthanum and gadolinium oxynitrates doped with Eu[sup 3+], REONO[sub 3]:Eu[sup 3+] (RE=La and Gd) were measured at 77 and 300 K. The [sup 7]F[sub J] (J=0-5) energy level schemes for the 4f [sup 6] electron configuration were simulated by a C[sub 2v] phenomenological crystal field (CF). The nine non-zero CF parameters for the C[sub 2v] site symmetry reproduce the experimental energy level schemes with rms deviations of 7 and 5 cm[sup -1] for the LaONO[sub 3] and GdONO[sub 3] hosts, respectively. The CF effect is stronger in the lanthanum host although otherwise the CF parameters for the two oxynitrate hosts differ only slightly. The B[sup k][sub 2] (k=2, 4 and 6) values are low indicating only a slight deviation from a higher C[sub 4v] symmetry. The B[sup 2][sub 0], B[sup 4][sub 0] and B[sup 4][sub 4] parameters assume high values which are similar to those obtained previously for the other RE oxy compounds, i.e. oxyhalides, ...

International Nuclear Information System (INIS)

The present work describes the surface improvement and biocompatibility of TiAl_2_4Nb_1_0 intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. This improvement in surface properties of the intermetallic alloy is due to formation of a thin modified layer which is ...

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... astatine complexes astatine compounds coulomb energy effective charge

Science.gov (United States)

Al Fleig, PITA Analytic Sciences. 7th Earth Science Data Systems Working Group Meeting ..... The Reuse Industry in Brazil, CESAR, and the Reuse in Software ...

British Library Electronic Table of Contents (United Kingdom)

The estimation of numerical values of the mean distance of closest approach of ions, a, of alkaline-earth metal ion salts in aqueous solutions, determined from activity coefficients, as well as from different theoretical approaches, is presented and discussed.

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This frequently-asked-questions feature provides answers about earthquakes, faults, plate tectonics, and earth structure. Maps and diagrams are provided with some answers, and links to additional information and to related topics are included.

UK PubMed Central (United Kingdom)

We calculate the expected fluxes of cosmic ray nuclei with charge 5 ≤ Z ≤ 28 at various depths in the earth's atmosphere, taking into account the initial charge distribution,...Full Text Available

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... angular momentum cranking model even-even nuclei gadolinium 156 governor

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Topics covered include: Methods of Helium Injection and Removal for Heat Transfer Augmentation; The

International Nuclear Information System (INIS)

The extraction of rare earth elements, yttrium and aluminium from red mud resulting from alumina production with the ion-exchange resin KU-2-8n was studied. Experimental results are presented. The technology of hydrometallurgical processing of pulps obtained by sorption extraction of scandium from red mud is developed. It is shown that in the process of precipitation from sulfate sulfuric acid desorbate it became possible to obtain a high degree of rare earths deposition. The use of sodium hydroxide makes it possible to obtain a maximum deposition of rare earths and aluminium - 99.9 %. Aluminium leaching from crude composite concentrate gives a possibility to get concentrates which 15 - 20 times richer in yttrium and rare earths

British Library Electronic Table of Contents (United Kingdom)

Radioactive rare earth chlorides in waste LiCl-KCl molten salts have to be separated as a stable form to minimize waste volume and to achieve stable solidification. In this work, thermal behavior of rare earth chlorides (CeCl3, GdCl3, NdCl3, PrCl3) was investigated in an oxygen condition to recover rare earth oxides from a LiCl-KCl-RECl3 system. The rare earth chlorides in the LiCl-KCl molten salts were smoothly converted to an oxychloride form at a higher temperature than 650degreeC, except for CeCl3. CeCl3 was totally converted to an oxide from at a higher temperature than 450degreeC. The rare earth oxychlorides (GdOCl, NdOCl, PrOCl) were effectively converted to oxide forms at a higher temperature than 1100degreeC. It was confirmed that rare earth oxides can be recovered from a LiCl-KCl...

CERN Document Server

Most of the presently identified exoplanets have masses similar to that of Jupiter and therefore are assumed to be gaseous objects. With the ever-increasing interest in discovering lower-mass planets, several of the so-called super-Earths (i.e., with masses in the interval 1 M_earth < M < 10 M_earth), which are predicted to be rocky, have already been found. Here we report the possible discovery of a planet around the M-type star GJ 436 with a minimum mass of 4.8+/-0.6 M_earth and a true mass of ~5 M_earth, which makes it the least massive planet around a main-sequence star found to date. In contrast with other discoveries, the planet is identified from its perturbations on an inner Neptune-mass transiting planet (GJ 436b), by pumping eccentricity and producing secular variations in the orbital inclination. Analysis of published radial velocity measurements indeed reveals a ...

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Energy Technology Data Exchange (ETDEWEB)

Short communication. 6 refs., 2 figs.

Science.gov (United States)

This study examined the effect of sulfur-containing compounds on the storage stability of Jet A

Energy Technology Data Exchange (ETDEWEB)

On the basis of observations of the JTEC team, it appears that Japanese universities and research institutes are leading long-term R&D thrusts for development of new materials casting technologies. Significant efforts include amorphous metals, intermetallics, application of MHD in continuous casting of steel, and energy efficient furnace technology. Industrial R&D seems focused more on process improvements than on new product technologies, but significant efforts in new cast materials included cast metal matrix composites, materials substitutions for thinner wall products, and advanced ceramic products for foundry industry applications.

British Library Electronic Table of Contents (United Kingdom)

A method to achieve NMR of dilute samples in the earth's magnetic field by applying para-hydrogen induced polarization is presented. Maximum achievable polarization enhancements were calculated by numerically simulating the experiment and compared to the experimental results and to the thermal equilibrium in the earth's magnetic field. Simultaneous 19F and 1H NMR detection on a sub-milliliter sample of a fluorinated alkyne at millimolar concentration (1018 nuclear spins) was realized with just one single scan. A highly resolved spectrum with a signal/noise ratio higher than 50:1 was obtained without using an auxiliary magnet or any form of radio frequency shielding.

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... 80 Briefs New Television Transmitter 81 Matadi Satellite Earth Station Inaugurated (Kinshasa AZAP, various dates) 82 Ramazani Marks Opening ...

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The Asarco-Mission complex (image left) is an active producer of copper and molybdenum (important in making steel and other metal alloys), ...

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Aug 25, 2004 ... The Tropical Rainfall Measuring Mission or TRMM satellite provided this image of Typhoon Aere over the western Philippine Sea as it was ...

International Nuclear Information System (INIS)

An oxidative precipitation reaction of rare-earth chlorides in a LiCl-KCl molten salt was successfully carried out by a lab-scale apparatus. The conversion efficiency of the used rare earth chlorides into the insoluble precipitates was increased with the sparging time and temperature and was affected on oxygen sparger type. In the conditions of 700 .deg. C molten salt temperature and above 540min sparging time, the final conversion efficiencies were over 99% for all the experimented rare-earth chlorides. The hydrodynamic characteristics of an oxygen-molten salt two phase flow system are very important for a co-oxidative precipitation of rare earth elements

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Jan 5, 2004 ... Even if dinosaurs were cold-blooded, in the Mesozoic Era (when dinosaurs roamed the Earth), Antarctica was warm enough to have them. ...

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... rivers of the world, the Zaire is not an efficient transportation link because of many rapids and falls to negotiate between Kinshasa and the port city of Matadi. ...

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Apr 22, 2010 ... I believe that space exploration is not a ... plan for space exploration, especially in .... space exploration beyond low Earth orbit. ...

UK PubMed Central (United Kingdom)

The geographical arrangement of people on the surface of the earth is approximated by a mathematical equation of 361 terms. This is a convenient form for comparison with other distributions and for...Full Text Available

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English 2008 p. 132-133 Turkey Nishonov, Sh. Khujaev, S.

British Library Electronic Table of Contents (United Kingdom)

Earth degassing specifically of carbon dioxide CO2 is of increasing interest with respect to the global carbon budget, related climate effects, earthquake and volcano eruption mechanisms, as well as plant physiological reactions in gas-rich environments. Investigations in all of these disciplines require the detection of surface CO2 degassing structures and quantification of their emissions. We introduce minimal thermal change detection based on infrared imaging as a new remote sensing tool for the detection of earth surface thermal anomalies suiting among others to discover earth degassing locations of any origin. The method allows for seamless areal search and monitoring of degassing structures in any terrain. As proof of concept infrared imaging measurements were performed at the Bossol...

Science.gov (United States)

... Zinn, J., Hoerlin, H., and Petschek, AG, "The Motion of Bomb Debris Follow- ing the Starfish Test," Radiation Trapped in the Earth's Magnetic Field ...

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goals for multisensor co-registration and fusion. 6 - 12.5 Km ..... Beta-Test toolkit for cyclogenesis and early evolution of cyclones ...

Science.gov (United States)

The SHARP cannon. Hydrogen is compressed in the tube on top, the gun barrel is on bottom. When Jules Verne wrote in 1865 "From Earth to the Moon" he ...

Energy Technology Data Exchange (ETDEWEB)

Extraction of rare earths (La, Ce, Pr, Eu, Gd, Er, Yb) from nitrate solutions by melts of carboxylic acids of the C/sub 17/-C/sub 20/ fraction and stearic acid with paraffin, depending on the temperature (60-90 deg), phase contact time and their volume ratio (O:B from 1:5 up to 1:100), pH of the aqueous phase (2-6), rare earth concentration (10/sup -6/-10/sup -3/ m) is studied. It is shown that in the whole concentration range investigated rare earths are extracted quantitatively into the carboxylic acid melt of C/sub 17/-C/sub 20/ fraction at the equilibrium value of pH>=3.8, while into the melt of 0.1 M stearic acid in paraffin at pH>=4.5.

Science.gov (United States)

Aug 23, 2011 ... Earthquakes, Hurricanes and Stubborn Instruments ... And if earthquakes and stubborn instruments aren't enough, there's this giant hurricane ...

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May 11, 2007 ... "Deforestation in the tropics accounts for nearly 20 per cent of carbon emissions due to human activities," Dr. Canadell says. ...

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Features: FOREST, DEFORESTATION, RIO JAMARI Geographic Region: BRAZIL .... Features: DEFORESTATION, TIERRAS BAJAS DEFORESTATION Geographic Region: BOLIVIA ...

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Zinn, John;. Hoerlin,. Herman; and Petschek,. Albert. G.: The Motion of Bomb. Debris. Following the Starfish. Test. Radiation. Trapped in the Earth's ...

Energy Technology Data Exchange (ETDEWEB)

Aimed at post-graduate and post-doctoral researchers in geochemistry, this book reflects the rapid changes in the applications of radioactive and stable isotope analysis to a range of geological and geochemical problems. Isotropic chemistry and methods used in mass spectroscopy are discussed initially. The second section deals with radiometric dating methods. The role of isotopes in climate and environmental research is also explored. The book closes with a section on extra-terrestrial matter, geothermometry and the isotopic geochemistry of the Earth`s lithosphere. (UK).

Energy Technology Data Exchange (ETDEWEB)

Clays and zeolites are among the most important of natural dusts by virtue of their occurrence through out the world on the earth`s surface and their important industrial uses. (The 1:1 layer silicates, including the serpentine and kaolin minerals, are not addressed in this chapter.) This chapter provides basic information on a variety of important aspects of each mineral, including crystal structure diagrams of each and references to more detailed discussions. 110 refs., 20 figs.

CERN Document Server

Among the billions of planetary systems that fill the Universe, we would like to know how ours fits in. Exoplanet data can already be used to address the question: How common are Jupiters? Here we discuss a simple analysis of recent exoplanet data indicating that Jupiter is a typical massive planet rather than an outlier. A more difficult question to address is: How common are Earths? However, much indirect evidence suggests that wet rocky planets are common.

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...Observatory Edinburgh SkyView Virtual Observatory Solar System Simulator Space Telescope Science Institute Space Weather : A Research Perspective Subaru Telescope Project Two Micron All ...Universities for Research in Astronomy Subjects: space observation DeweyClass: 522 Resource type: index Space Weather : A Research Perspective Documents discussing space weather , the ...elements of near-Earth space, Earth-space meteorology and practical consequences of space weather . Glossary included. Author: National Academy of ...

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When a bipolar HVDC transmission system is operating monopolar using the earth as a return path, it is often desired to divert the return current from the earth to the line from the unused pole. To do so requires either that the system be shut down temporarily or that a dc circuit breaker be used. This paper describes the development of such a new dc circuit breaker, and its application on the Pacific Intertie as a Metallic Return Transfer Breaker (MRTB).

CERN Document Server

The bright star 55 Cancri is known to host five planets, including a transiting super-Earth. The interferometric study presented here yields directly determined values for 55 Cnc's stellar astrophyiscal parameters: $R=0.943 \\pm 0.010 R_{\\odot}$, $T_{\\rm EFF} = 5196 \\pm 24$ K. We use isochrone fitting to determine 55 Cnc's age to be 10.2 $\\pm$ 2.5 Gyr, implying a stellar mass of $0.905 \\pm 0.015 M_{\\odot}$. Our analysis of the location and extent of the system's habitable zone (0.67--1.32 AU) shows that planet f ($M \\sin i = 0.155 M_{Jupiter}$) spends the majority of the duration of its elliptical orbit in the circumstellar habitable zone, where, with moderate greenhouse heating, it could harbor liquid water. Finally, our direct value for 55 Cancri's stellar radius allows for a model-independent calculation of the physical diameter of the transiting super-Earth 55 Cnc e ($\\sim 2.05 \\pm 0.15 R_{\\earth}$), which, ...

UK PubMed Central (United Kingdom)

Some biological effects of hypoglycin-A, a compound isolated from the fruit of Blighia sapida, have been investigated. Administration of this compound to animals caused drowsiness...Full Text Available

UK PubMed Central (United Kingdom)

Woolfolk, C. A. (University of Washington, Seattle). Reduction of inorganic compounds with molecular hydrogen by Micrococcus lactilyticus. II. Stoichiometry with inorganic...Full Text Available

Science.gov (United States)

The report contains general information on aluminium and aluminium compounds concerning the existing standards, emissions, exposure levels and effect levels. The document is to be considered as a first evaluation to be used for the national discussion dur...

International Nuclear Information System (INIS)

... organic compounds other organic compounds separation processes

International Nuclear Information System (INIS)

We present a unified description of the imaginary part of the dynamical magnetic susceptibility #chi#"'"'(#omega#.T) and measurements of the static susceptibility #chi#(T) and electrical resistivity #rho#(T) in the uranium intermetallics UCu_5_-_xPd_x (x = 1.1.5). For temperatures T and excitation energies #omega# in the range 12 K < #omega#, T < 150 K, our analysis demonstrates that the dynamics of isolated uranium ions are responsible for the observed temperature and frequency scaling, although interion interactions may become important at lower temperatures and frequencies. We derive a strict criterion for single-ion scaling in the form of a universal scaling function, providing a model-independent description of the compiled experimental data. (orig.).

International Nuclear Information System (INIS)

The published literature is reviewed and supplemented by current information from the author's laboratory, to show the influence of various compositional, heat treatment and thermomechanical factors on the structural characteristics of Alloy 800. The features discussed include carbon, aluminium, titanium and boron, solution treatment, ageing treatments with and without applied strain, and cold working. Examples of the aspects reviewed include the effect of heat treatment and service or testing temperature on the austenite grain size, and the relative importance of M_2_3C_6 and TiC, the influence of carbon level on gamma prime, the effect of residual or steady stress combined with time at temperature on changes in carbide or gamma prime morphology, and on the appearance of sigma or other intermetallic phases. The questions posed by these features are discussed generally, in terms of their effect on the mechanical properties at ambient and elevated temperatures and ...

British Library Electronic Table of Contents (United Kingdom)

The need for alternative energy increases steadily???especially due to the climate change and the limited availability of fossil fuels. Geothermal power uses the intrinsic heat which is stored in the accessible part of the Earth???s crust. Its importance among the renewable energy resources originates from the almost unlimited energy supply of the Earth and its independence from external influences such as seasonal or even daily climatic variability. Nevertheless, there are risks which have to be assessed. From a mathematical point of view there are four building blocks of the characterization of deep geothermal systems: seismic exploration, gravimetry, modeling transport processes, and modeling the stress field. In particular, local depletion poses a significant risk during the industrial...

International Nuclear Information System (INIS)

The desire to study negative ion structure and negative ion-photon interactions has spurred the development of ion sources for use in research and industry. The many different types of negative ion sources available today differ in their characteristics and abilities to produce anions of various species. Thus the importance of choosing the correct type of negative ion source for a particular research or industrial application is clear. In this study, the results of an investigation on the production of beams composed of negatively-charged rare-earth ions from a cylindrical-cathode-geometry, cesium-sputter-type negative ion source are presented. Beams of atomic anions have been observed for most of the first-row rare-earth elements, with typical currents ranging from hundreds of picoamps to several nanoamps.

Energy Technology Data Exchange (ETDEWEB)

The object of this program was to design and build a self-contained system for remote monitoring of the atmosphere in mines. The system developed uses the mine pager phone line as the primary communication channel and also has the capability of using 208 Hz in the ELF band for wireless transmission through the earth. The depth for through-the-earth transmission is expected to be about 80 to 90 meters in high conductivity soil and is limited by the noise level in the ELF band-pass filters. The underground components of the TEM System are energized by mine power through a battery charger-storage battery power supply. In the event of mine power failure the battery capacity is more than sufficient for 1 week's operation with interrogations every 4 hours.

British Library Electronic Table of Contents (United Kingdom)

We present an empirical model for periodic variations of diurnal and sub-diurnal Earth rotation parameters (ERPs) that was derived based on the transformation of normal equation (NEQ) systems of Very Long Baseline Interferometry (VLBI) observing sessions. NEQ systems that contain highly resolved polar motion and UT1-TAI with a temporal resolution of 15?min were generated and then transformed to the coefficients of the tidal ERP model to be solved for. To investigate the quality of this model, comparisons with empirical models from the Global Positioning System (GPS), another VLBI model and the model adopted by the conventions of the International Earth Rotation and Reference Systems Service (IERS) were performed. The absolute coefficients of these models agree almost completely within 7.5?...

KoreaScience (Korea)

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Science.gov (United States)

... biologically important compounds is sharply lowered with passage of the solutions to the cell an organ, where their sensitivity ...

CERN Document Server

A Multi-Channel Algebraic Scattering (MCAS) theory is presented with which the properties of a compound nucleus are found from a coupled-channel problem. The method defines both the bound states and resonances of the compound nucleus, even if the compound nucleus is particle unstable. All resonances of the system are found no matter how weak and/or narrow. Spectra of mass-7 nuclei and of {}^{15}F, and MCAS results for a radiative capture cross section are presented.

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International Nuclear Information System (INIS)

... odd nuclei organic compounds radiation effects radioisotopes synthesis

International Nuclear Information System (INIS)

... compounds plants radiation effects radioisotopes reaction kinetics trees

Wastenet

...contributions from the following fields: Catalytic elimination of environmental pollutants, such as nitrogen oxides, carbon monoxide, sulfur compounds, chlorinated and other organic compounds, ...contributions from the following fields: Catalytic elimination of environmental pollutants, such as nitrogen oxides, carbon monoxide, sulfur compounds, chlorinated and other organic compounds, ...

British Library Electronic Table of Contents (United Kingdom)

Metalloid cluster compounds of group 14 of the general formulae EnRm with n > m (E = Si, Ge, Sn, Pb; R = ligand), where naked as well as ligand bound tetrel atoms are present, represent a novel class of cluster compounds in group 14 chemistry and can be seen as intermediates on the way to the elemental state. Therefore, interesting properties are expected for these compounds, which might complement results from nanotechnology. In this article, first results for germanium are discussed, together with novel build-up reactions on the way to novel materials based on metalloid cluster compounds. GRAPHICAL ABSTRACT[image omitted

Science.gov (United States)

Incoming solar energy had to be assimilated to sustain it. .... Roll stability was achieved with an Earth sensor mounted on the directional antenna. .... Once more a rocket becomes the means of producing a vector change in velocity. ...

UK PubMed Central (United Kingdom)

BackgroundDinoflagellates are unicellular, often photosynthetic protists that play a major role in the dynamics of the Earth's oceans and climate. Sequencing of dinoflagellate nuclear...Full Text Available

Science.gov (United States)

Dolores Beasley Headquarters, Washington, DC July 19, 2000 (Phone: 202/358- 1753) Bill Steigerwald Goddard Space Flight Center, Greenbelt, MD (Phone: ...

UK PubMed Central (United Kingdom)

BackgroundGeographic Information Systems (GIS) can provide valuable insight into patterns of human activity. Online spatial display applications, such as Google Earth, can democratise...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Types of disorders in the earth's surface as a result of open pit mining operations are analyzed. Trends for recultivation of lands are defined. Formulas are presented for calculating the economic expediency of the selected direction of recultivation.

UK PubMed Central (United Kingdom)

More than 30 years ago, human beings looked back from the Moon to see the magnificent spectacle of Earth-rise. The technology that put us into space has since been used to assess the damage...Full Text Available

Science.gov (United States)

BAE SYSTEMS Infrared Imaging Systems. MS 209. 2 Forbes Road. Lexington, MA 02421 -7306. (781) 863-3762. (781) 863-4809 (fax) ken.overoye @lmco.com ...

Energy Technology Data Exchange (ETDEWEB)

The Earth`s troposphere and hydrosphere contain abundant naturally generated dust. The ultimate source materials from which the terrestrially produced dust is generated are the various rock types exposed at the Earth`s surface. Natural dust is a composite of (1) lithic, primary mineral grains; (2) mineral grains formed by secondary chemical reactions; (3) volcanic ash and dust; (4) salts from sea sprays; (5) extra-terrestrial dust; and (6) biologic materials. In this paper the various pathways to the natural generation of dust (via the hydrologic cycle) will be discussed, and two geologically well-known natural dust sources will be described, paying particular attention to quantitative measurements of the dusts from these areas. General dust studies that provide data on possibly global background levels will be presented as well.. A few general aspects of the mineralogical characterization of dust particles and a discussion of some of the ...

International Nuclear Information System (INIS)

Instrumental neutron activation analysis (INAA) and radionuclide X-ray fluorescence analysis (RXFA) were used for the determination of rare earth elements. For INAA, solution obtained by sample decomposition was dripped onto filter paper, enclosed and sealed into a polyethylene foil. The sample was activated in reactor WWR-S over a period of 4 to 6 hours with a neutron fluence of 10"1"3cm"-"2. Gamma radiation measurement was carried out with a planar and a coaxial HP-Ge detector in three decay periods. La, Ce, Nd, Sm, Eu, Gd, Tb, Ho, Tm, Yb and Lu were determined. The advantage of the method is its accuracy and high sensitivity, the disadvantage is the time-consuming analysis. The RXFA method was used as a rapid and operative method for the analysis of loose ore samples, aqueous and organic solutions of rare earth elements. For exciting X-ray radiation, "2"4"1Am was used and the radiation of K-lines was detected with a planar Si(Li) detector. ...

Science.gov (United States)

Recent proposals have shown that a quantum degenerate gas of alkaline earth atoms can be used for a number of novel quantum computing and quantum simulation experiments. Strontium is a good candidate for such experiments because it can be controlled with high precision, as demonstrated in recent atomic clock experiments. Unfortunately, the small scattering length of strontium is not amenable to evaporative cooling techniques that are used to reach quantum degeneracy. Furthermore, increasing the scattering length of alkaline earths with a magnetic Feshbach resonance is not possible due to their spinless electronic ground state configuration. However, recent theoretical and experimental work suggests the possibility of changing scattering lengths in alkaline earths with laser light. Using this optical Feshbach resonance near strontium's narrow ^1S0->^3P1 intercombination transition might allow its scattering length to be ...

Science.gov (United States)

Federated Search (openSearch) (C. Lynnes); Infusion Process (S. Olding) Metrics Planning & Reporting (R. Ramapriyan); Service & Event Casting (B. Wilson) ...

UK PubMed Central (United Kingdom)

In 18 months the Canadian Medical Discoveries Fund (CMDF) has attracted investments worth $180 million to spend on biotechnology and medical research. Although eight initial investments totalled only...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

An introduction to time-of-flight neutron spectroscopy is presented in the context of the study of magnetic materials. Examples are taken from the class of rare earth and actinide magnetic materials known as `strongly correlated electron` systems. (author) 11 figs., 24 refs.

Science.gov (United States)

Features: CHUQUICAMATA, LARGE OPEN PIT MINING OPERATIONS, ROADS, HILLS Center Point Latitude: -22.3 Center Point Longitude: -68.9 (Negative numbers indicate ...

Science.gov (United States)

It was thus actually the fourth stage of the rocket assembly. ... package, and several temperature sensors - was mounted in the cross-lattice frame. ... Earth's geomagnetic field and incoming charged particles from the Sun and extra-solar space. ...

Science.gov (United States)

... say for sure if the signal is coming from hail, lots of graupel, or some other hydrometeor . ... Precipitation forms when cloud droplets or ice particles in clouds grow and .... A landslide is the movement of rock, debris, or earth down a slope. ...

Wastenet

... 03, 2001 | Rate It Lake Superior Streams http://www.lakesuperiorstreams.org/ (1 vote) interactively examine real-time water quality data from 5 ...north shore Lake Superior trout streams and learn about other streams in the region, how they \\

Wastenet

...October 2006 - present: University of Leeds, UK PhD Candidate in Geochemistry Thesis Title: Magnetite formation in reducing natural environments Supervisors: Dr Liane G. Benning ...Germany Bachelor of Science in Geosciences and Astrophysics Project Details Project Title: \\

UK PubMed Central (United Kingdom)

BackgroundDengue fever is a mosquito-borne illness that places significant burden on tropical developing countries with unplanned urbanization. A surveillance system using Google...Full Text Available

UK PubMed Central (United Kingdom)

Investigations of psychrotrophic microorganisms have been limited even though the dominant environment of the Earth is cold and enzymes with high activities at low temperatures could have commercial...Full Text Available

Science.gov (United States)

ISS022, E, 8260, CHILE, CHUQUICAMATA, LARGE OPEN PIT MINING OPERATIONS, ROADS, HILLS, -22.3, -68.9, 20091209. ISS022, E, 8261, CHILE, CHUQUICAMATA, ...

Science.gov (United States)

Sep 9, 2009 ... You are here: GES DISC Home Geomorphology from Space By Location Landforms by Location: Asia. Info. Landforms by Location: Asia. KEY, ASIA ...

Science.gov (United States)

An ascending node occurs when the subsatellite point crosses the earth's equator going from .... 11dB sigma-naught. This error budget includes the altimeter noise, ...... it is also recommended to filter the data as follows to ...

Science.gov (United States)

...Pneumatic-tired earth-moving haulage equipment (trucks, scrapers, tractors...Pneumatic-Tired Earthmoving Haulage Equipment. An employer may, of course...pneumatic-tired earthmoving haulage equipment, is suspended pending...

Energy Technology Data Exchange (ETDEWEB)

Time-temperature-precipitation diagrams have been established for two steels with 6% Mo, 21% Cr, 25% Ni, 0.14 and 0.19% N (Cronifer 1925 h Mo = 1.4529, UNS N 08925) and for one steel with 6% Mo, 20% Cr, 18% Ni and 0.21% N (UNS S 31 254). The corresponding time-temperature-sensitization diagrams (in accordance to SEP 1877/II) and time-temperature-pitting diagrams (testing in 6% FeCl{sub 3} solution) have been evaluated as well. Precipitation of intermetallics occurs rapidly especially in the range between 700 and 1000{sup 0}C. In case of the 18% Ni steel and the 25% Ni/0.14% N steel grain boundaries are covered to a large extent with precipitates after only 15 min at 850 or 950{sup 0}C. In case of the 25% Ni/0.19% N steel precipitation is considerably slower. Therefore, when welding according to established rules and recommendations, no deterioration of the corrosion resistance in the heat-affected zone is to be expected. Additionally, the steel with 25% Ni has an ...

British Library Electronic Table of Contents (United Kingdom)

This paper summarizes the establishment and current development of space activities in the Bolivarian Republic of Venezuela. Space activities in Venezuela are focused on the areas of telecommunications, Earth observation and research on the physical properties of the Earth, and have as a primary goal the satisfaction of social needs. Current development of space activities started in 1999 when the new National Constitution recognized the value of outer space as the common heritage of mankind, and the key role of science and technology in promoting human welfare. The Bolivarian Agency for Space Activities (ABAE) was created in 2007. Its legal framework recognizes three key elements that drive its policy: the participation of society, capacity building and human training, and international c...

Energy Technology Data Exchange (ETDEWEB)

When in resonance, Raman scattering exhibits strong enhancement ranging from four to six orders of magnitude. This physical phenomenon has been applied to remote sensing of the Earth`s atmosphere. With a 16 inch Cassegrain telescope and spectrometer/ CCD-detector system, 70-150 ppm-m of SO{sub 2} in the atmosphere has been detected at a distance of 0.5 kilometer. This system can be used to detect/monitor chemical effluence in the atmosphere by their unique Raman fingerprints. Experimental result together with detailed resonance Raman and atmospheric laser propagation effects will be discussed.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a process for preparing poly(aryl ether ketones) by nucleophilic displacement polymerization in the presence of at least one alkali metal base selected from potassium, rubidium or cesium, and fluoride ions, which comprises adding to the polymerization: (a) an effective amount of at least one metal salt selected from lithium, sodium, alkaline earth or lanthanide chloride, bromide, iodide, sulfate, alkyl or aryl carboxylate, cyanide, borate or phosphate to slow or stop advancement of molecular weight and (b) an end-capping agent.

Energy Technology Data Exchange (ETDEWEB)

Climates at regional scale are strongly dependent on the interaction between atmosphere and its lower boundary, the oceans and the land surface mosaic. Land surfaces influence climate through their albedo, and the aerodynamic roughness, the processes of the biosphere and many soil hydrological properties; all these factors vary considerably geographically. Land surfaces receive a certain portion of the solar irradiance depending on the cloudiness, atmospheric transparency and surface albedo. Short-wave solar irradiance is the source of the heat energy exchange at the earth`s surface and also regulates many biological processes, e.g. photosynthesis. Methods for estimating solar irradiance, atmospheric transparency and surface albedo were reviewed during the course of this project. The solar energy at earth`s surface is consumed for heating the soil and the lower atmosphere. Where moisture is available, evaporation is one of the key components of ...

International Nuclear Information System (INIS)

Superconductivity in A-15 compounds is examined in terms of electron pairing induced by exchange of acoustic plasmons. The electronic band structure of Nb_3Sn, V_3Si, and similar materials favor transition temperatures of Tsub(c)approximately20 K. (Auth.).

UK PubMed Central (United Kingdom)

We describe an Ebolavirus minigenome-based system that is suitable for high-throughput screening of compounds able to impair Ebolavirus virus replication and/or transcription....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The OH-initiated photo-oxidation of n-butane was used as a source of 1- and 2-butoxy radicals. Reactions producing ketones and other organic compounds are explained. Rates of photolysis were determined and are discussed.

UK PubMed Central (United Kingdom)

Although cross-resistance in houseflies to the organophosphates has eliminated numerous potentially useful compounds from field use, the ”subgroup” specificity of this phenomenon has...Full Text Available

UK PubMed Central (United Kingdom)

Microbial degradation of aromatic hydrocarbons has been studied with the aim of developing applications for the removal of toxic compounds. Efforts have been directed toward the genetic manipulation...Full Text Available

International Nuclear Information System (INIS)

K_#beta#/ K_#alpha# x-ray intensity ratio of chromium were measured in different chromium compounds. The results show the variation of the intensity ratio as a function of the chemical environment around the metal ion. (author)

Science.gov (United States)

Methods of acidizing a subterranean well formation, acidizing compositions, and sequestering additives for preventing the precipitation of metal compounds in the formation are described. Use of the methods and chemicals described should lead to improved formation permeability as compared to use of previous methods and chemicals. 12 claims.

International Nuclear Information System (INIS)

... properties organic bromine compounds organic solvents ph value phenols

Energy Technology Data Exchange (ETDEWEB)

The objectives of this project were to develop feasible synthetic routes to produce (1) 4(4{prime}-hydroxy-5{prime}6{prime},7{prime}8{prime}-tetrahydro-1{prime}-naphthylmethyl)-6-methyldibenzothiophene, and (2) a 1-hydroxynaphthalene-dibenzothiophene polymer. These compounds are thought to be representative of sulfur containing molecules in coal. The program was divided into two technical tasks. Unfortunately, the attempted syntheses of these compounds was unsuccessful due to their unusual reactivities. Attempted synthetic routes and possible future routes are described, and Appendix A lists the compounds that were synthesized during this program.

DEFF Research Database (Denmark)

Udgivelsesdato: 2002-Aug

International Nuclear Information System (INIS)

... atp-ase azido compounds biochemical reaction kinetics endoplasmic reticulum

International Nuclear Information System (INIS)

Portuguese 2004 [1 p.] Brazil Souza Filho, Paulo Artur Coelho de

British Library Electronic Table of Contents (United Kingdom)

Abstract Silicates are one of the most important classes of compounds on this planet, and more than 1000 silicates have been identified in the mineral kingdom. Additionally, several hundreds of artificial silicates have been synthesized. The substitution of oxygen by nitrogen leads to the structurally diverse and manifold class of nitridosilicates. Silicon nitride, one of the most important non-oxidic ceramic materials, is the binary parent compound of nitridosilicates, and it symbolizes the inherent material properties of these refractory compounds. However, prior to the last decades, a broad systematic investigation of nitridosilicates had not been accomplished. In the meantime, these and related compounds have reached a remarkable level of industrial application. This review illustrates...

International Nuclear Information System (INIS)

The magnetic susceptibility of the ternary compounds, RPd_2Si_2 (where R=Gd, Tb, Dy, Ho and Er) has been measured. GdPd_2Si_2 and TbPd_2Si_2 order antiferromagnetically at 13 and 20 K respectively; the rest of the compounds do not show clear ordering down to 4.2 K. Palladium carries no moment in these compounds. The De Gennes formula is not obeyed indicating that the exchange interaction between the 4f moments via conduction electrons is not isotropic. (orig.).

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Certain radioiodine containing esters useful as brain imaging agents are disclosed. The formula of these compounds are presented.

International Nuclear Information System (INIS)

In the case of inelastic scattering of alpha particles to the 3"+ state, the averaged angular distributions show a characteristic shape, corresponding to the excitation of such an unnatural parity state by alpha particles in the compound nucleus process. The modified Hauser-Feshbach cross-section calculations give a good description of the averaged distributions for the alpha particle scattering to the 3"+ state and the compound nucleus parameters could be extracted. The calculations of the compounds nucleus contributions to the other states in the case of 24 MeV alpha particle scattering from "2"8Si show that this contribution is not negligible and in the case of the scattering to the 4"+ state seems to be dominant. (Z.M.).

Energy Technology Data Exchange (ETDEWEB)

Chemical effects of L X-ray intensity ratios in niobium and molybdenum compounds were studied by electron and proton bombardments. L{sub {gamma}1} X-rays which involve transition of 4d electrons of the valence shell were found to be sensitive to the chemical environment. The L{sub {gamma}1}/L{sub {beta}1} X-ray intensity ratio increased with an increase of the 4d electron occupation of niobium or molybdenum in niobium or molybdenum compounds, showing that the chemical effects can be ascribed to the 4d electron behavior of the metallic atom in its compounds. (orig.).

Science.gov (United States)

... Abstract : The inherent brittleness of the A-15 compounds, and the requirement for a filamentary morphology, led to a heavy reliance on a powder ...

International Nuclear Information System (INIS)

Certain radioiodine containing amides useful as brain imaging agents are disclosed. The compounds of the subject invention are represented by the formula.

International Nuclear Information System (INIS)

Based on results from recent studies of elemental dietary intake and organ or tissue content for adult Chinese men, quoted nationwide elemental concentrations in Chinese soil and newly published national average consumption of dietary foods, values of both transfer coefficients and discrimination factor (DF) for transfer from soil via the diet to both critical organs and the whole body have been calculated for important elements in radiation protection, including alkaline earths, alkali metals, rare earths and other related elements. These calculations have used both the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) model and the DF method. In the UNSCEAR model, the basic parameters used to describe the transport of radionuclides are the transfer coefficients P_i_j, which describe the relationship of concentrations or other amounts between compartment i and the following compartment j, whereas the DF is the ...

Energy Technology Data Exchange (ETDEWEB)

The completed ribbon-winding theory, including temperature loading of the high-pressure compound vessel, was proposed. The influence of the bending stress in the wound ribbon is taken into account. Internal core of the compound vessel consists of matrix and ring, made of different materials. The relations were derived in analytical form, describing the radial distribution of necessary tangential prestressing.

Energy Technology Data Exchange (ETDEWEB)

Graphite intercalation compounds, Rb{sub x}KC{sub 8}, Cs{sub x}KC{sub 8} and Na{sub x}KC{sub 8}, x{approx equal}1-1.3, are obtained under pressures up to 80 kbar using KC{sub 8} as the initial compound. Total contents of alkali metals in these compounds correspond to the formula MC{sub 3.5-4.0}. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The bibliography contains citations concerning the properties of tantalum and tantalum compound films formed by sputtering techniques. Topics include processes, and electrical, magnetic, and dielectric properties of the sputtered films. Tantalum compounds studied include nitrates, oxides, and aluminides. The structural properties of sputtered films are also discussed. (Contains a minimum of 105 citations and includes a subject term index and title list.)

Energy Technology Data Exchange (ETDEWEB)

This project (a) demonstrated specific dopamine transporter (DAT) uptake in vivo and metabolic stability of a radiolabelled cycloplentadieny rhenium compound in rats and baboons, (b) showed that cyclopentadieny tricarbonyl rhenium and technetium compounds conjugated tropanel could be made by metal transfer with ferrocenes; and (c) explored new methods of synthesizing these compounds under mild conditions.

Energy Technology Data Exchange (ETDEWEB)

The irreducible representations associated with states of dipole symmetry have been calculated for the space groups O/sub h//sup 3/, the space group with the correct symmetry for A-15 phase compounds. Also assembled are the character tables of the O/sub h/3 group. Thus all thedirect interband dipole-transition selection rules for A-15 compounds can easily be determined.

International Nuclear Information System (INIS)

Chemical effects on the intensity ratio of LX-ray of molybdenum compounds irradiated by 11-keV electrons and by 3-MeV protons were studied using an x-ray crystal spectrometer. It was found that the intensity ratios of L_#gamma#_1/L_#beta#_1 markedly decrease with the increase of ionicity of molybdenum compounds, except for the case of metallic molybdenum. (author).

CERN Document Server

Amperostatic coulometry was applied for the thickness measurement of Sn-Ag hot dip coatings, which comprise an extended Sn-Cu interdiffusion layer. Complementary measurements, notably weight loss, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, X-ray fluorescence (XRF), and dynamic secondary ion mass spectroscopy were performed in order to obtain a better interpretation of the coulometry results. Based on the experimental results presented in this article, the three potential changes observed during coulometry measurements are ascribed to (i) the entire dissolution of pure Sn, (ii) the formation of a CuCl salt layer, and (iii) the surface passivation. The measurement of the pure Sn mass is well reproducible despite strong coating thickness variations detected by XRF. Several experimental problems, in particular, a coating undercutting, hamper the determination of the Sn mass in the intermetallic Sn-Cu layer. (19 refs).

International Nuclear Information System (INIS)

Neutron powder diffraction and magnetometric studies of the HoRh_2_-_xPd_xSi_2 series of solid solutions (x=0, 0.5, 0.75, 1.0, 1.5, 1.8) are reported. The intermetallics investigated crystallize in the body-centred-tetragonal ThCr_2Si_2-type structure (space group I4/mmm). All the samples order antiferromagnetically at low temperatures. For low values of the dilution parameter x a simple collinear antiferromagnetic structure of the AFI type is stable. Below T_N the magnetic moments are parallel to the c-axis and then, below T_t, deflect forming an angle #psi# with the c-axis. Further replacement of Rh by Pd results in the development of a sine-wave-modulated magnetic structure with one two-component propagation vector and magnetic moments in the basal plane. For x=1.8 a sine-wave-modulated structure similar to that reported for HoPd_2Si_2 (i.e. with a two-component propagation vector and magnetic moments parallel to the b-axis) was found. (author)

Science.gov (United States)

We present results of electronic structure calculations for the intermetallic perovskite Sc3InB with the full-potential KKR-LDA method. Sc3InB is a very promising candidate for a new superconductor (related to 8 K MgCNi3) and can be regarded as a boron-inserted cubic Sc3In, which is a high-pressure allotropic form of the hexagonal weak ferromagnet Sc3In. We predict that cubic Sc3In can also be magnetic, whereas Sc3InB having large DOS in the vicinity of E F exhibits non-magnetic ground state. Estimation of the electron-phonon coupling for Sc3InB gives 1. Furthermore, the effect of vacancies in Sc3InB1-x and antisite disorder in Sc3(In-B) on critical parameters is also discussed using the KKR-CPA method. All theoretical results support the possibility of the superconductivity onset in Sc3InB. Preliminary experimental measurements established the transition temperature close to 4.5 K, with a very abrupt change in susceptibility and a correlated drop of the ...

International Nuclear Information System (INIS)

Silicon nitride-based ceramics behavior is strongly influenced by microstructural parameters, which, in turn are determined by chosen densification method. Highly covalent Si-N bond hind are the silicon nitride densification. Therefore, metal oxides are used in order to get high density. However, such oxides must be carefully selected, because they affect the general macroscopic properties of sintered bodies. In the present work, the viability of rare earth concentrate use to produce #beta#--Si_6_-_xAl_xO_xN_8_-_x and its effect on mechanical properties of the sintering ceramics are studied. Additive composition, heating rate, soaking time and sintering temperature were took as variables. Hardness, fracture toughness, Young's modulus and flexural strength were investigated. Lattice parameter compositional dependence and secondary phases crystallized after past-sintering heat treatment were also determined. The results show that rare earth ...

CERN Document Server

In this paper, we first calculate the realistic Earth matter effects on the detection of type II supernova neutrinos at the Daya Bay reactor neutrino experiment which is currently under construction. It is found that the Earth matter effects depend on the neutrino incident angle \\theta, the neutrino mass hierarchy \\Delta m_{31}^{2}, the crossing probability at the high resonance region inside the supernova, P_H, the neutrino temperature, T_{\\alpha}, and the pinching parameter in the neutrino spectrum, \\eta_{\\alpha}. We give the expression for the dependence of P_H on the neutrino mixing angle \\theta_{13}. With this we obtain the relations between \\theta_{13} and the event numbers for various reaction channels of supernova neutrinos. Using these relations, we propose a possible way to measure \\theta_{13} smaller than 1.5^\\circ. Such a sensitivity cannot be achieved by the Daya Bay neutrino experiment (the sensitivity of the Daya Bay ...