bluuebunny/crossref_metadata_2025_split huggingface dataset:
Themal spray and adhesive bonding of optical fibres to high‐temperature compsie materials
Authors: Henkel Daniel P. 
Published: May 2005

AbstractMicrostructural characteristic were identified for three surface‐mounted optical fibre sensors which were thermal spray bonded to high‐temperature composite materials. The primary objective was to determine the defect generation mechanisms that occur during thermal cycling and to make processing and testing recommendations that would optimise the sensor performance. A second objective was to identify areas of microstructural research that would have the most significant impact on the development of high‐temperature smart materials.The smart material systems of the present study were comprised of (1) silica optical fibre sessors bonded to titanium matrix composites (TMCs) using a nickel‐based thermal spray, (2) silica optical fibre sensors bonded to TMCs using ceramic cement and (3) sapphire optical fibre sensors bonded to titanium matrix composites (TMCs) using a nickel‐based thermal spray, (2) silica optical fibre sensors bonded to TMCs using ceramic cement and (3) saphire optical fibre sensors bonded to carbon–carbon composites (CCCs) using ceramic cement. The thermal and prior to any thermal stresscycling. In combination with the non‐metallic spheroidal inclusions of the titanium matrix, the microcracking provided a mechanism for disbonding the optical fibres with a subsequent loss of sensor performance. A high degree of kporosity in both systems containing ceramic cements significantly reduced the interfacial bonding area. This, combined with the inherent ceramic brittleness, caused disbonding of the optical fibres in the cemented systems.
Growth of chromium‐doped alumina thin films by metal‐organic chemical vapour deposition
Authors: Chiu Hsin‐Tien , Lin Been‐Hon 
Published: May 2005

AbstractAmorphous thin films of chromium‐doped alumina were grown from Al(OiPr)3 (iPr, Isopropyl) and Cr(CO)6 on silicon and quartz substrates by chemical vapour deposition at 673 K. The films were annealed at 1223 and 1473 K to form chromium‐doped γ‐Al2O3 and γ‐Al2O3respectively. The lattice constant a of the γ‐Al2O3thin films enlarged with increasing Cr Concentration. The lattice constant a (=b) of the α‐Al2O3 thin films increased while the lattice constant c decreased with increasing Cr concentration. UV‐visible spectra of the annealed films showed maximum absorptions near 380, 500 and 690 nm.
p‐Doping of GaAs and AlGaAs using the triethylamine adduct of dimethylzinc
Authors: Jones Anthony C. , Rushworth Simon A. , O'Brien Paul , Walsh John R. , Meaton Clive 
Published: May 2005

AbstractThe adduct between dimethylzinc and triethylamine has been used as a p‐dopant source in the growth of GaAs and Al0.3Ga0.7As alloys by metalorganic vapour phase epitaxy (MOVPE). The dopling efficiency of this adduct in these alloys and in InP is lower than that of dimethyl zinc.
Two‐Wavelength switching of luciferase activity using caged compounds
Authors: Chittock R. S. , Wharton C. W. , Jackson J. B. , Lidzey D. G. , Berovic N. , Beynon T. D. 
Published: May 2005

AbstractFirefly luciferase, luciferin, 1‐(3,4‐dimethoxy‐6‐nitrophenyl) elthyl ATP and 1‐(2‐nitrophenyl) ethyl acetic acid were immobilised in an agarose gel matrix. By illuminating the gel with 350 nm light through a mask, a positive bioluminescent pattern was written on to the gel by releasing ATP in the illuminated areas. The gel was then illuminated with a brpadbnand UV light through a second mask to release acetic acid, lowering the local pH and deactivating the enzyme. This produced a negative image of the second mask superimposed on the positive image of the first mask.The system represents a two‐wavelength switch in which one wavelength of light activates the enzyme while a second deactivates it. This demonstrates the feasibility of using biological molecules as logic element in future devices.
Dynamic displacement anisotropy of atoms, streamer discharges and phonon focusing in BeO and CdSe crystals and I–VII compounds
Authors: Zubritskii V. V. , Zaitsev A. M. 
Published: May 2005

AbstractStreamer discharges at 77 K and crytallographically oriented surface spark breakdown at 295 K have been obtained in BeO crystals. An inverted temperature dependence has been found for the breakdown anisotropy compared with that in CdSe crystals. It is shown that the temperature dependences of the excitation thresholds of the incomplete electric breakdown at different crystallographic orientations in dielectrics as well as those of the streamer discharges in hexagonal semiconductors are controlled by the anisotroply of ionic dynamic displacements. The directions of maximum phonon focusing have been calculated in the localoisation planes of the incomplete breakdown in NaCl, KBr and LiF crystals at room temperature in accordance with well‐known breakdown model along phonon streams. It is shown that the alkali halide breakdown data do not agree with this model. An anisotropy is predicted of the dynamic displacement of atoms in alkali halide crystals as well as in the basis plane and mirrorsymmetric directions of planes containing the crystallographic c‐axis in hexagonal II–VI compounds, which allows us to explain the observable particularities of the discharge anisotropy in both cubic and hexagonal crystals.
Electron‐beam‐pumped laser emitters with microrelief mirrors based on II–VI semiconductors
Authors: Gribkovskii V. P. , Gurskii A. L. , Kulak I. I. , Lutsenko E. V. , Mitcovets A. I. , Yablonskii G. P. 
Published: May 2005

AbstractThe power characteristics of electron‐beam‐pumped emitters based on II–VI compounds have been stukdied. The use of a microrelief with direction‐selective reflective properties instead of a totally reflecting miror has made it possible to provide effective sukppression of closed non‐characteristics and efficiency of lasers and to make them suitable for obtaining generation with high efficiency in a number of media, in particular YAG:Nd3+, KGW:Nd3+ and Lif:F (OH), at room temperature.
Crystallographic orientation and light emission of streamer discharges in II–VI semiconductors
Authors: Gribkovskii V. P. , Gurskii A. L. , Lutsenko E. V. , Yablonskii G. P. 
Published: May 2005

AbstractSome results of Investigations on the crystallographic orientation, luminescence and stimulated emission of streamer discharges in monocrystals of hexagonal CdS, CdSe and ZnO and cubic Znsand Snseare presented.
Growth of yttrium oxide thin films from β‐diketonate precursor
Authors: Mölsä Heini , Niinistö Lauri , Utriainen Mikko 
Published: May 2005

AbstractYttrium oxide thin films were deposited in a flow‐type ALE reactor from Y(thd)3 (Hthd  2,2,6,6‐tetramethyl‐3,5‐heptanedione) and either ozone or oxygen. The influence of the substrate and source temperatures, pressure and pulse durations on the film growth on soda‐lime and silicon substrates was studied. Films were also grown on Corning glass, sapphire and Si/CeO2 substrates to study the effect of the substrate on the growth rate and crystallinity of the films. Spectrophotometry, XRD and AFM were used to determine the optical properties, thickness, crystallinity and surface morphology of the films. All the films deposited with ozone were crystalline, but differences in preferential orientation depending on the substrate were observed. The growth rate with ozone was about 0.8 Å cycle−1 on all substrates except sapphire where it was higher. The films deposited with oxygen were less crystalline and the growth rate was significantly lower than in depositions with ozone under the same growth conditions.
Identification of the impurity phase in chemically deposited CdS thin films
Authors: Sebastian P. J. , Hu Hailin 
Published: May 2005

AbstractIdentification of the impurity phase present in chemically deposited CdS thin films and in the precipitate used for screen printing CdS/CdTe solar cells is reported in this paper. X‐ray diffraction (XRD) studies of the films and the precipitate showed that the impurity phase is a mixture of cadmium oxide sulphate (Cd3O2SO4) and cadmium oxide (CdO). Analysis of the films and the powders obtained using thiourea (TU) and thioacetamide (TA) as sulphursing agents showed that the impurity phase is predominantly present when TU is used in the chemical bath. The high conductivity shown by chemically deposited CdS films (using TU) when annealed at higher temperatures in air is attributed to the predominance of the conducting CdO phase in the film.
Nearly resonant third‐order optical non‐linearity in c60 cast films
Authors: Henari Fryad Z. , Blau Werner J. , Seldon Declan N. 
Published: May 2005

AbstractWe have carried out measurements of the third‐order optical non‐linearityX(3) of C60 cast films using the z‐scan technique. The measurements have shown that two‐photon absorption is the dominant non‐linear process around the 3.76 eV absorption region. The real and imaginary parts of X(3) of C60 films have been measured at 665 nm are found to be 2.8 × 10−8 and −3.2 × 10−8 esu respectively.
Optically stimulated intersubband absorption in undoped amorphous Si/SiO2 qiantum well
Authors: Keller Ole , Zayats Anatoly , Vinogradov E. A. 
Published: May 2005

AbstractIntersubband absorption has been observed in undoped amorphous multiple‐quantum‐well (MQW) strucctures under interband excitation. The transitions take place between the first and second subbands of the conduction band and involve non‐equilibrium electrons excited into the first subband by optical pumping. The absorption band FWHM of 0.1 eV is much larger than for crystalline MQWs, a fact which reflects the relaxation of the electron momentum conservation in the QW plane. The high joint density of states and oscillator strength for the intersubband transitions in amorphous QWs allow one to observe the absorption at low electron concentrations (Ne ≈ 1013 cm−3) in the ground conduction subband.
A comparative study of pulsed laser deposition and flash evaporation of Culn0.75Ga0.25Se2 thin films
Authors: Ahmed E. , Hill A. E. , Pilkington R. D. , Tomlinson R. D. , Levoska J. , Kusmartseva O. , Leppävuori J. 
Published: May 2005

AbstractIn this paper initial results are presented for the growth and characterisation of polycrystalline Culn0.75Ga0.25Se2 thin films prepared by pulsed laser deposition and flash evaporation. Analogies are drawn between these two important deposition technologies. The deposited films were characterised using a veriety of analytical techniques, including energy‐dispersive analysis of X‐rays and Rutherford‐backscattering spectroscopy for compositional evaluation, X‐ray diffreaction and Raman spectroscopy for structural evaluation, scanning electron microscopy for surface examination and the four‐point and hot‐point probe techniques for electrical characterisation. The comparison of films produced by these two deposition methods revealed that, in terms of their stochiometry, electrical and physical characteristics, good‐quality GIGS thin films could be produced by both techniques.
The X‐ray crystal and molecular structure of [Ba(TDFND)2.tetraglyme], the first molten barium precursor for MOCVD applications
Authors: Nash Jason A. P. , Barnes John C. , Cole‐Hamilton David J. , Richards Barbara C. , Cook Stephen L. , Hitchman Michael L. 
Published: May 2005

AbstractAt 150 K [Ba(TDFND)2, tetraglyme] crystallises in the P1/c space group with a = 17.15(2) Å b = 10.735(5) Å, c = 22.830(7) A, β = 97.56 (7)°, V = 4165 (5) Å3, Z=4. R1 = 0.0435, wR2 = 0.1079. The barium atom is nine‐co‐ordinate, with binding to all the O atoms. The two BaTDFND rings are planar but tilted by 26° from being co‐planar. The five O atoms of the tetraglyme ligand are also essentially co‐planar, but this plane subtends angles of 88.8(1)° and 67.4(1)° to the two BaTDFND planes. The BaO (TDFND) bond lengths are longer than for other related compounds, but the BaO (tetraglyme) bond lengths are similar to those in [Ba(HFA)2.tetraglyme] (HFA  CF3C(O)CHC(O)CF3). The low melting point and the fact that [Ba(TDFND)2.tetraglyme], alone of barium complexes of this kind, can be evaporated without decomposition at 1 atm are attributed to lower intermolecular forces for this compound and to its greater thermal stability.
IR and UV laser‐assisted deposition from titanium tetrachloride: A comparative study
Authors: Alexandrescu R. , Cireasa R. , Dragnea B. , Morjan I. , Voicu I. , Andrei A. , Vasiliu F. , Popescu C. 
Published: May 2005

AbstractLaser‐induced TiCl4 decomposition at vapour pressure was performed and comparative study of the composition and structure of thermally (at 10.6 μm) and photolytically (at 248 nm) deposited Ti‐based films is presented. Emphasis was given to the less explored titanium deposition process by CO2 laser pyrolysis of TiCl4. The detailed structure of films deposited on quartz substrates was examined by scanning electron microscopy and X‐ray photoelectron spectroscopy. The influence of the incident laser energy on the chemical content of the films as well as on the film growth rate was demonstrated. The results indicate that in the thermal IR decomposition of TiCl4 a multilayer structure is formed with unsaturated TiSix at the interface and oxidized phases at the surface. The photolytic process leads to films with increased purity and a specific growth morphology.
Electrical conductivity of 1,4‐dihydroxyanthraquinone and the complex silver/dihydroxyanthraquinone
Authors: Nasrallah T. Ben , Bernède J. C. , Jamali M. 
Published: May 2005

AbstractQuinizarin (1,4‐DHAQ) and Ag/I,4‐DHAQ thin films deposited under vacuum were investigated by I–V measurements at various temperatures. It is shown that when submitted to an electric field of 5 × 105 V cm−1 or less, the I‐V characteristics of AI/DHAQ/AI sandwich structures are ohmic. The temperature dependence is I ∝ exp(‐ΔE/kT). The measured activation energy is 0.3 eV in the case of pure DHAQ and 30meV in the case of Ag/DHAQ. Therefore we can imagine that in the former case the conductivity is controlled by thermally activated hopping above intermolecular barriers, while in the latter case the conductivity can be attributed to tunnelling between silver grains.
Optically synaptic films using spiropyran J‐aggregates
Authors: Miyata A. , Matsushima T. , Ohki H. , Unuma Y. , Higashigaki Y. 
Published: May 2005

AbstractSpiropyran SP1822 J‐aggregate LB films show a non‐linear photochromic response with a threshold against the incident light intensity of a CW dye laser. Using two laser beams operating below the threshold level intensity, the logic ‘AND’ function was found to be optically stored as an overlapping region of two incident patterns. We proposed the adoption of an LB film of spiropyran J‐aggregates to store the memory matrix Tijkl as an overlapping region of learning input pattern Vij and multi‐image input pattern Vkl in order to construct an optical neural network system based on Hopfield model.
Preparation and purification of metal fluorides for crystals and glasses
Authors: Kinsman B. E. , Hanney R. 
Published: May 2005

AbstractThe development of low‐loss fluoride glass fibres for transoceanic telecommunications led to an increased demand for inorganic fluorides with ultrahigh purity in respect of transition metals, rare earths and oxygen. This review paper describes the Merck Ltd strategy for achieving a wide range of metallic fluorides using methods of preparation and purification selected for a combination of technical efficacy and economic practicability. General preparative methods involving aqueous and non‐aqueous routes are described, together with purification methods such as ion exchange, zone refining and vacuum sublimation. The special role of ammonium fluoride complexes is discussed. The application of these general methods to the manufacture of fluoride glass components is described, with special reference to the ZBLAN formulation. Additional glass compositions and their individual requirements are also discussed. The parallel application of high‐purity metal fluorides in the growth of optical crystals is emphasised, the history of fluoride ultrapurification having begun with the early demand for high‐quality UV and IR crystals such as CaF2 and LiF.
Characterisation of TiN films prepared by electron shower, arc ion‐plating and sputtering methods
Authors: Yumoto H. , Kaneko K. , Ishihara M. , Akasi K. , Kaneko T. 
Published: May 2005

AbstractIt has been found that TiN films with high wear resistance and high adhesion can be prepared by electron shower deposition and arc ion plating on glass and austenitic stainless steel (SUS 316) substrates. The high wear resistance is principally explained by the grain size and surface morphology. Fine {100}‐faceted crystals (10–150 nm) grew on the surface. The typical morphology of the crystals was triangular pyramidal. The crystallite size was changed by the bias voltage. Faceted crystals produced by arc ion plating were rounded and smoothed by a change in bias, but were unaltered in samples prepared by the electron shower process. The fine faceted surfaces had higher wear resistance than the granularly rounded ones. When TiO2 was formed at the interface of the glass substrate, the adhesion was lowered. The high‐adhesion film prepared by electron shower deposition contained a small amount of TiO2 at the interface.
Coupling monolayers for protection of microelectronic circuits
Authors: Fabianowski Wojciech , Jaccodine Ralph , Kodnani Ramesh , Pearson Raymond , Smektala Piotr 
Published: May 2005

AbstractTwo polymeric coatings, a silicone gel (Dow Corning 6646) and an epoxy resin (Dexter FP 4402), were glob‐top coated onto representative microelectronic circuits, AT&T Triple Track Testers (TTTs), and subjected to the Pressure Cooker Test (PCT). Coupling monolayers were self‐ assembled on the TTTs prior to encapsulation to improve the moisture protection capabilities of the coatings. Leakage current measurements were made to evaluate the effect of applied monolayers on the moisture protection capability. The moisture protection capability was assessed in short‐term and long‐term leakage current measurements. MHDA (16‐mercaptohexadecanoic acid) and APS (gamma‐aminopropyltriethoxysilane) monolayers, in combination with silicone gel and epoxy resin respectively, exhibited very good moisture protection performance.
Irregular shifts of excitonic states in reflectivity and PL spectra of ZnSe crystals under uniaxial stress
Authors: Negrii V. D. , Kulakov M. P. 
Published: May 2005

AbstractSplittings and shifts of excitonic states in ZnSe crystals under uniaxial stress along [100], [111] and [110] directions were studied by spatially resolved spectroscopy of both the reflectivity and the photoluminescence (PL) at 5 K. These methods enabled us to check the local strains in different surface microareas of deformed crystals and as a result to reveal the irregular free and bound exciton state shifts related to the influence of the strain nonuniformity and to the presence of structural imperfections (twins) in the crystals. It is shown that elastic deformation of twinned crystals along directions not exactly [111] gives rise to a doublet structure for all the bound exciton lines in the PL spectra. New values of deformation potentials for ZnSe crystals were deduced. The anisotropic influence of the uniaxial stress on the free and bound exciton state splittings was determined.
Molecular image‐processing devices based on chemical reaction systrems. 3: Some operational characteristics of excitable light‐sensitive media used for image processing
Authors: Rambidi N. G. , Maximychev A. V. 
Published: May 2005

AbstractOperational features of excitable Belousov–Zhabotinsky‐type light‐sensitive media that can be used to implement image‐processing operations are discussed. They embrace (i) the main primitive responses of such media to light excitation as a function of medium acidity, temperature and light exposure, (ii) the characteristics of temporal evolution of stored media and (iii) the resolution and information content inherent in images stored by excitable media. It is shown that controlling the acidity of the medium, its temperature and the duration of light exposure enables one to get reproducible results.
Molecular image‐processing devices based on chemical reaction systems. 4: Image‐processing operations performed by active media functioning in the oscillating mode
Authors: Rambidi N. G. , Maximychev A. V. 
Published: May 2005

AbstractBasic primitive image‐processing operations performed by chemical dynamic media functioning in the oscillating mode are discussed. These operations have rather high computational complexity and can be considered as simulation of human vision capabilities.
MOCVD of group III chalcogenides
Authors: Barron Andrew R. 
Published: May 2005

AbstractA review is presented of recent advances in the metal organic chemical vapour deposition (MOCVD) of thin films of group III chalcogenides, including their application for the passivation of GaAs surfaces. The majority of studies involve the deposition of thermodynamic phases of composition ME and M2E3 (MGa, In; ES, Se, Te), however, MOCVD allows for the growth of either high‐pressure (tetragonal InS) or non‐thermodynamic phases (metastable cubic phases of GaS and InSe). Based on the results to date, a series of goals for molecular control over the structure of deposited films is discussed.
Direct observation of the stacked structure in substituted copper phthalocyanine LB films with STM
Authors: Zlatkin A. , Yudin S. , Simon J. , Hanack M. , Lehman H. 
Published: May 2005

AbstractThe in‐plane molecular structures of octa‐alkyl substituted copper phthalocyanine LB films deposited on graphite have been resolved with a scanning tunnelling microscope (STM). The face‐to‐face stacking of Pc macrocycles has been observed in the topographies of R8PcCu monolayers. The stacking period was found to be 3.8–4 Å and the molecular rows were separated by 19 Å and 16 A for (C6H13)PcCu and (C5H11)PcCu respectively.
Effect of nitrogen addition on optical properties of fluorozirconate glasses
Authors: Samek L. , Miniewicz A. 
Published: May 2005

AbstractThe linear and non‐linear optical properties of fluorozirconate glasses with and without nitrogen, namely ZrF4BaF2LaF3AIF3 and ZrF4BaF2LaF3AIF3AIN, have been studied. The glass containing nitrogen exhibits a 5 nm shift of the transmittance edge in the UV region towards longer wavelength, whereas there is no change in the IR transmittance. Measurements show a small increase in the linear index of refraction in the visible region and a small decrease in the non‐linear (intensity‐dependent) refractive index coefficient n2. Longitudinal and transverse sound velocities estimated from Brillouin‐scattering experiments for both glasses amount to 6311 and 4514 ms−1, respectively.
Implanted polymer junctions obtained with electrogenerated polythiophene films
Authors: Lucas B. , Rodriguez J. , Otero T. F. , Guille B. , Moliton A 
Published: May 2005

AbstractUsing polythiophene films (∼5 μm thick) electrogenerated by trapezoidal waves of potential, then partially reduced, we realised metal‐polythiophene contacts on the one hand. The electrical characteristics of a steel/polythiophene/gold sandwich structure are presented. We consider that the rectifying contact takes place between steel and p‐type polythiophene. On the other hand, we showed that p‐type polythiophene could be compensated after an implantation of alkali ions (Cs+ or Na+) in order to lead to the realisation of PN junctions. We particularly prove that the use of Na+ ions results in junctions yielding currents which are higher than with Cs+ ions. Current‐voltage and capacitance‐voltage characteristics have been presented so as to show that the junction effect is due to the efficiency of the doping by ionic implantation. These electrical measurements seem to be stable after several weeks in air.