Showing papers on "Single crystal published in 1986"
TL;DR: Dynamic behavior of ultrafine particles of gold around 20 A\r{} in size was examined at the level of the atomic resolution by an electron microscope equipped with a real-time video recording system.
Abstract: Dynamic behavior of ultrafine particles of gold around 20 A\r{} in size was examined at the level of the atomic resolution by an electron microscope equipped with a real-time video recording system. In real time, it was observed that the shape of the particles changed continually through an internal transformation from a single crystal to a twinned crystal, and vice versa. The transformations were induced to some extent by the irradiation of the electron beam. They took place abruptly in less than 0.1 sec.
535 citations
TL;DR: In this paper, the kinetics of the CO-O2 and CO-NO reactions over single crystal Rh(111) and over alumina-supported Rh catalysts have been compared at realistic reactant pressures.
444 citations
TL;DR: In this paper, the same phenomenon was observed in Zn1−xFex(ptz)6(BF4)2 (x ≈ 0.1) and is therefore basically a single-ion property, and the phenomenon is reversible.
280 citations
TL;DR: The pedestal growth method as mentioned in this paper has been shown to be a fast, simple, and inexpensive means to produce single crystals for property evaluation, making it an extremely valuable tool for surveying new materials.
249 citations
TL;DR: In this article, it was shown that the Pt (100) surface undergoes reconstruction due to hydrogen adsorption above 0.3 of a monolayer and the combined effect of low oxygen coverage with high hydrogen coverage induces a new type of voltammogram.
175 citations
TL;DR: Blavette et al. as discussed by the authors investigated the role of re-contalning in improving the creep strength of Ni-base superalloys, using the FIM-atom probe.
155 citations
01 Jul 1986
TL;DR: In this paper, the crystal structure of a synthetic ZrO2 has been studied in situ up to 51 kbar at room temperature, where the directions of the b and c axes are preserved through the transition and the transformation is displacive.
Abstract: Combining a miniature diamond-anvil pressure cell with a single crystal four-circle diffractometer, the crystal structure of a synthetic ZrO2 has been studied in situ up to 51 kbar at room temperature. The space group of the unquenchable orthorhombic high pressure phase is Pbcm. The directions of the b and c axes are preserved through the transition and the transformation is displacive. The coordination configurations of the Zr atoms and oxygen atoms are the same in the high pressure and low pressure phases. The orthorhombic high pressure phase has a higher entropy than that of low pressure monoclinic phase.
144 citations
Patent•
09 Sep 1986
TL;DR: In this paper, an isolating groove is formed by selective etching (isotropic etching) by using KOH in a single-crystal silicon substrate and an insulating SiO2 film is deposited on the entire surface.
Abstract: PURPOSE:To make it possible to form a resistor or a wiring beneath an element region in a dielectric isolating structure by surrounding the entire surface of a single crystal region which is isolated with a non-single crystal silicon that is embedded in a groove formed in a semiconductor substrate with a three-layer structure of an insulating film, a conductor layer and an insulating film. CONSTITUTION:An isolating groove 12 is formed by selective etching (isotropic etching) by using KOH in a single-crystal silicon substrate 11. An insulating SiO2 film 13 is deposited on the entire surface. Then, a wiring layer 14 having the thickness of 100-1,000Angstrom is formed with conductive material (e.g., high- melting-point metal such as nickel chromium) by an evaporating method. An insulating film SiO2 film 15 is deposited again. Then a supporting layer 16 is formed by growing polycrystalline silicon. Etching is performed to a position shown with a broken line. A dielectric isolated substrate having a single crystal region 17 that is isolated with the SiO2 film 13 and the conductive layer 14 that is isolated with the insulating SiO2 films 13 and 15 can be obtained without using especially complicated steps. When the conductive layer 14 is utilized as a resistor, polycrystalline silicon whose resistivity is controlled by ion implantation can be used.
142 citations
TL;DR: In this article, the phase relations in the Cu,In,Se system are reviewed with particular attention to compositions in the vicinity of CuInSe 2, and the pseudobinary Cu 2 Se-In 2 Se 3 is re-evaluated and the liquidus-solidus relationship of the δ phase is discussed.
140 citations
TL;DR: In this paper, the effects of adsorbed anions such as NO−3 and Cl− are compared with those obtained with a special vacuum transfer system, and several of the factors controlling hydrogen adsorption on Pt and particularly anion effects are discussed.
132 citations
TL;DR: In this article, the electrical conductivity of alkylthio-substituted tetrathiafulvalene (TTCn-TTF) single crystal has been measured in a vacuum of 10−4 Pa with the two probe method.
Abstract: The electrical conductivity of alkylthio-substituted tetrathiafulvalene (TTCn-TTF) single crystal has been measured in a vacuum of 10−4 Pa with the two probe method. The room temperature dark condu...
TL;DR: In this article, a series of vanadium pentoxide films were sputter deposited on glass substrates using a vanadium target and rf-excited Ar/O2 discharges containing 2% to 8% O2.
Abstract: A series of V–O alloy films were sputter deposited on glass substrates using a vanadium target and rf-excited Ar/O2 discharges containing 2%–8% O2. On the basis of x-ray results, the films were nominally identified as vanadium pentoxide. Optical transmission and reflection characteristics were measured by double-beam spectrophotometry in the 390- to 700-nm-wavelength region. From these measurements, the absorption coefficient α was determined as a function of the incident photon energy hν. The absorption edge of all films showed two distinct regions of behavior: a high photon energy region in which α varied linearly with (hν)2 and a low-energy tail. The behavior of α is discussed in terms of the structural and electronic changes in the films due to nonstoichiometry and compared to results obtained for single crystal V2O5.
TL;DR: In this article, the authors proposed a method for electrochemical faceting of polycrystalline metal wires, which can be applied either electrochemically through conventional voltammetry in the H and O electroadsorption/electrodesorption potential range, or by scanning electron microscopy.
TL;DR: Analyse du spectre de luminescence a 4,8 K, d'un monocristal a tres faible concentration de chrome as mentioned in this paper, a 4.8 K.
TL;DR: In this paper, a model based on the thermoelectric potential generated by axial and radial temperature gradients was proposed to explain the domain structures observed in these fibers, which is different from those usually observed in large LiNbO3 crystals.
TL;DR: In this article, the effect of interface shape changes and on and off facet growth on the impurity distribution of GaSb was investigated and the most important correction to the distribution constant was shown to be based on interface shape change and on-off facet growth as freezing proceeds.
TL;DR: In this article, the photorefractive properties of a single crystal of BaTiO3 were altered by treating the crystal at 650°C in oxygen at different partial pressures.
Abstract: The photorefractive properties of a nominally pure single crystal of BaTiO3 were altered by treating the crystal at 650°C in oxygen at different partial pressures. Treatment altered the effective density of photorefractive charge carriers in the crystal and could convert an inactive crystal into an active one. Treatment at low oxygen pressure (reduction) decreased the temperature of the tetragonal-to-cubic phase transition of the crystal and also decreased the measured optical band gap, implying that oxygen vacancies had been introduced into the bulk crystal. These oxygen vacancies are associated with negative photorefractive charge donors. Either hole transport or electron transport dominated, depending on whether the partial pressure of oxygen was greater than or less than ½ atm during treatment. The competing roles of electrons and holes are discussed.
TL;DR: In this article, analytical solutions for the melt motion in a Czochralski puller with a strong, uniform, axial magnetic field were presented for determining the amount and distribution of dopants and oxygen in the crystal.
Abstract: A magnetic field suppresses turbulence and thermal convection in a Czochralski crystal puller The amounts and distributions of dopants and oxygen in the crystal are determined by the motion of the molten silicon during crystal growth This paper presents analytical solutions for the melt motion in a Czochralski puller with a strong, uniform, axial magnetic field The relatively small electrical conductivity of the crystal plays a key role in determining the flow Certain combinations of crystal and crucible rotation rates lead to flow patterns with a large volume of almost stagnant fluid under most of the crystal face The values of these rotation rates depend on the magnetic field strength
TL;DR: In this paper, a single crystal superalloy with various crystallographic orientations was tested in compression at room temperature, 650, 760, 870, and 980 °C.
Abstract: Single crystal superalloy specimens with various crystallographic orientations were tested in compression at room temperature, 650, 760, 870, and 980 °C. These results are compared with the tensile behavior studied previously. The alloy, Rene* N4, was developed for gas turbine engine blades and has the nominal composition 3.7 Al, 4.2 Ti, 4 Ta, 0.5 Nb, 6 W, 1.5 Mo, 9 Cr, 7.5 Co, balance Ni, in weight percent. Slip trace analysis showed that primary cube slip had occurred even at room temperature for the [111] specimens. With increasing test temperature more orientations exhibited primary cube slip, until at 870 °C only the orientations near [001] and [011] exhibited normal octahedral slip. The yield strength for octahedral slip was numerically analyzed using a model proposed by Lall, Chin, and Pope to explain deviations from Schmid’s law in the yielding behavior of a single phase γ’ alloy, Ni3(Al,Nb). The Schmid’s law deviations in Rene N4 were found to be largely due to a tension-compression anisotropy. This is one of the sources of the Schmid’s law violations observed in Ni3(Al, Nb) which are rationalized by the model. A second effect, which increases the strength of orientations away from [001], was found to be small in Rene N4. Analysis of recently published data on the single crystal superalloy PWA 1480 yielded the same result.
TL;DR: In this article, the optical and catalytic properties of molybdenum sulfide edge planes have been studied in single crystals and disordered powders, and it has been shown that the edge sites are similar in the amorphous and crystalline materials and derive turnover numbers and absorption cross sections for these sites.
TL;DR: The various melt-growth techniques used to grow single crystals of CuInSe 2 are reviewed and typical experimental procedures are described and discussed in this paper, where a brief description of the problems associated with electrical doping is included.
TL;DR: Synchrotron-radiation-excited angle-resolved photoemission from a single crystal of natural graphite is reported, with photon energies between 20 and 65 eV, and the photon-energy dependence of normal emission spectra yielded a dispersion of less than theoretically predicted.
Abstract: Synchrotron-radiation-excited angle-resolved photoemission from a single crystal of natural graphite is reported. Using photon energies between 20 and 65 eV, all the valence-band dispersions and critical-point binding energies have been determined. The photon-energy dependence of normal emission spectra yielded a \ensuremath{\pi}-band ${k}_{z}$ dispersion of \ensuremath{\sim}1 eV, less than theoretically predicted. Distinct secondary-electron features in the spectra allow determination of the dispersion of certain conduction bands lying up to 20 eV above the Fermi level. Such high-energy conduction bands have not been observed by inverse photoemission.
TL;DR: In this paper, a series of Mg doped congruent LiNbO3 crystals were investigated by UV a nd IR spectrophotometry and AC conductivity.
TL;DR: In this article, the authors applied AES and LEED to the study of silicon surface segregation on Fe−3wt%Si single crystals between 400 and 900°C, and showed that the repelling of Si by C on the surface is mainly due to a site competition reaction, whereby the strong Si-C repulsive interaction plays a minor role.
TL;DR: In this paper, the site occupation probability of the substitutional elements between the nickel and aluminum sites of the ordered Ll/sub 2/ lattice was determined by measuring the composition of successive planes in the ordered lattice.
TL;DR: In this article, the effect of pressure on the bond compressibility in the crystal structures of fayalite, Fe2SiO4 and rutile, TiO2 were investigated by using a diamond anvil cell designed for this study and a four-circle single crystal X-ray diffractometer.
Abstract: The effect of pressure on the bond compressibility in the crystal structures of fayalite, Fe2SiO4 and rutile, TiO2 were investigated by using a diamond anvil cell designed for this study and a four-circle single crystal X-ray diffractometer. The mean linear compressibilities of the FeO, SiO and TiO bonds were 0.22 Mbar−1, 0.05 Mbar−1 and 0.18 Mbar−1, respectively. A general principle that the longer bond is more compressible than the shorter one is in accord with the present results only within the stability field.
TL;DR: In this article, a tetrapropylammonium (TPA) ZSM-5 zeolite was studied by X-ray diffraction techniques in the orthorhombic space group Pnma.
TL;DR: In this article, mass spectral analysis is used to determine the elemental composition, as a function of temperature, of the adsorbed monolayers of the alk-1enes, propene, but-1-ene, pent-1ene and isobutene chemisorbed on the (111) face of a Pt single crystal.
Abstract: Thermal desorption combined with mass spectral analysis is used to determine the elemental composition, as a function of temperature, of the adsorbed monolayers of the alk-1-enes, propene, but-1-ene, pent-1-ene and isobutene chemisorbed on the (111) face of a Pt single crystal. Vibrational electron energy loss spectroscopy (EELS) is used to assign structures to the surface species adsorbed at different temperatures. At the lowest temperatures (below 200 K) it is concluded that in each case these alk-1-enes are bonded to the metal surface in the form of di-$\sigma$-bonded non-dissociatively adsorbed species. The simplicity of the EEL spectrum from the species derived from isobutene provides additional support for an earlier assignment to the di-$\sigma$-adsorbed species for ethylene on Pt(111). At ca. 300 K the EEL spectra and thermal desorption data are consistent with the presence of alkylidyne, M$\_3$C(CH$\_2$)$\_n$CH$\_3$ (M = metal; n = 1, 2 or 3) or M$\_3$CCH(CH$\_3$)$\_2$ structures for the chemisorbed species respectively, (M = metal atom). For temperatures above 300 K the thermal desorption results show substantial further loss of hydrogen, a process which commences at lower temperatures the longer the hydrocarbon chain. Near 450 K the thermal desorption data indicate average C:H compositions of approximately C$\_3$H$\_2$ for the species derived from propene, C$\_4$H$\_2$ from but-1-ene, and C$\_4$H$_4$ from isobutene. The EEL spectra are used to indicate the remaining hydrocarbon functional groups present at this and at higher temperatures. Above 450 K closely similar spectra were obtained from all the straight-chain butenes including the cis- and trans-but-2-enes and buta-1,3-diene whose spectra are discussed in more detail in the following paper. The EEL spectra indicate the occurrence of C-C bond breaking in general above ca. 500 K, the onset temperatures being somewhat dependent on the adsorbed hydrocarbon.