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The structure, elemental and phase composition of Fe-C eutectic alloy obtained by the contact interaction of diamond with low-carbon steel in vacuum were studied. Cylindrical tablets of low carbon steel containing not more than 0.1 % wt. C and natural diamond crystals were used as a contact pairs. Diamond crystals in the form of a pyramids were mounted by their flat base on the horizontal surface of steel tablet. Contact samples were sintered under load in a vacuum furnace at a maximum heating temperature of ∼1165 °C. Sintered diamond-metal tablet contact pairs were studied by optical and scanning electron microscopy, X-ray diffraction analysis. It was determined that the Fe-C eutectic melt forms in the diamond-metal tablet contact zone, a thin layer of which, when solidified, welds a diamond crystal to the metal tablet under the specified in the experiment temperature-time heating mode. It was shown that the Fe-C eutectic alloy is a gray cast iron with a ferrite-perlite metal base and a plate graphite inclusions. The microhardness of the solidified Fe-C eutectic was ∼1714 MPa. [ABSTRACT FROM AUTHOR]

The results of the study of the parameters of the surface layer of a LiF crystal irradiated by Ag or Cu ion beam through a metal mask in the form of a grid with a period of 7 µm are presented. It was shown that a composite layer with a thickness of 3–5 µm is formed in the crystal in the form of a periodic structure containing F2 and F3+ color centers and (sub)nanometer metal particles. A diffraction pattern is observed on this structure upon irradiation with a laser beam. [ABSTRACT FROM AUTHOR]

The metal complexes of Schiff bases derived from heterocyclic compounds have been the centre of attraction for many researchers in recent years. The solvent evaporation method was employed to obtain the different Ternary Metal complexes of Cr(III) in the crystal format. In present investigation optical characterization such as IR absorption spectroscopy and UV - VIS absorption spectroscopy were carry out. The fingerprint region of all the crystals discussed in the concern chapter with the reference scientific data. The UV-VIS absorption spectra were obtained to identify band gap of all samples. Tauc methods were carried out to calculate the band gap using UV-VIS spectra. The obtained results was compared with the reference data available in the digital library and found similar. The thermal behavior (TGA) of the complexes was studied and kinetic parameters were determined by Broido method. Transition Metal complexes of Cr(III), with different Schiff base have been synthesized . They were characterized by Thermo gravimetric analysis studies. Kinetic Parameters, such as energy of activation (Ea), enthalpy (ΔH#), entropy (ΔS#) and Gibbs energy (ΔG#), were computed from the TGA data using Broido method. The authors carried out the measurement and calculation with all the scientific evidence. [ABSTRACT FROM AUTHOR]

Most of rolled sheet metals belong to orthorhombic aggregates of cubic crystallites. The texture coefficients, characterized by the preferred orientation of the crystallites, are important to set up the yield function. Although Hosford yield function is more suitable for describing both yield and plastic deformation of orthorhombic material than Hill, it suffers from the restriction that the three principal stresses have to be coaxial with the orthotropy of materials. Hence, this paper proposes a new Hosford yield function of cubic orthorhombic metal sheet at any stress states by introducing orientation-dependent functions. As well, the new yield function which covers 3 material parameters and 3 texture coefficients is more general than Hosford yield function. The plastic anisotropy of the q-value and yield stress under any stress states is obtained from the new yield function. This yield function lay a theoretical foundation for analyzing the mechanical properties of metal materials. [ABSTRACT FROM AUTHOR]

High crystalline metal thin film preparation in application both for catalyst substrate or electrode in any electronic devices always to be considered in material functional material research and development. As a substrate catalyst, this metal take a role as guidance for material growth in order to resulted in proper surface structure although at the end it will be removed via etching process. Meanwhile as electrodes, it will dragging charges to be collected inside. This brief discussion will elaborate general fundamental principle of physical vapor deposition (PVD) system for metal thin film preparation in micro-nanometer scale. The influence of thermodynamic parameters and metal characteristic such as melting point and particle size will be elucidated. Physical description of deposition process in the chamber can be simplified by schematic evaporation phenomena which is supported by experimental measurement such as SEM and XRD. [ABSTRACT FROM AUTHOR]

The cosmogenic production of long-lived radioactive isotopes in materials is an hazard for experiments demanding ultra-low background conditions. Although NaI(Tl) scintillators have been used in this context for a long time, very few activation data were available. We present results from two 12.5 kg NaI(Tl) detectors, developed within the ANAIS project and installed at the Canfranc Underground Laboratory. The prompt data taking starting made possible a reliable quantification of production of some I, Te and Na isotopes with half-lives larger than ten days. Tnitial activities underground were measured and then production rates at sea level were estimated following the history of detectors; a comparison of these rates with calculations using typical cosmic neutron flux at sea level and a selected description of excitation functions was also carried out. After including the contribution from the identified cosmogenic products in the detector background model, we found that the presence of ³H in the crystal bulk would help to fit much better our background model and experimental data. We have analyzed the cosmogenic production of ³H in NaI, and although precise quantification has not been attempted, we can conclude that it could imply a very relevant contribution to the total background below 15 ke in NaI detectors. [ABSTRACT FROM AUTHOR]

An ultra-low background coaxial HPGe detector for gamma-ray spectrometry with a relative efficiency of 160%, corresponding to a 600 cm3 Ge crystal, was installed at the Laboratoire Souterrain de Modane, France (4800 m.w.e). To reduce the instrinsic detector background, all parts involved in the detector cryostat were selected for their low radioactivity contamination. A shielding, composed of an inner layer of roman lead and an external layer of regular lead was installed, together with a system to reduce the Rn level inside the sample chamber. The shielding was designed to allow the measurement of Marinelli-shaped samples. We present the constructional details which lead to a remarkable low detector background of 73 cts/kg·d in [40, 3000] keV. Measured samples showed that sensitivities about 100 μBq/kg in 226Ra and 228Th are reached for samples of some kg and 30 days of lifetime. [ABSTRACT FROM AUTHOR]

Copper nanowires were fabricated within the pores of anodic alumina template (AAT) by template synthesis method at pH = 2.9. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to investigate the structure, morphology and composition of fabricated nanowires. These characterizations revealed that the deposited copper nanowires were highly crystalline in nature, dense and uniform. The crystalline copper nanowires are promising in application of future nanoelectronic devices and circuits. [ABSTRACT FROM AUTHOR]

With 741 kg of TeO2 crystals and an excellent energy resolution of 5 keV (0.2%) at the region of interest, the CUORE (Cryogenic Underground Observatory for Rare Events) experiment aims at searching for neutrinoless double beta decay of 130Te with unprecedented sensitivity. Expected to start data taking in 2015, CUORE is currently in an advanced construction phase at LNGS. CUORE projected neutrinoless double beta decay half-life sensitivity is 1.6Ã--1026 y at 1s (9.5Ã--1025 y at the 90 % confidence level), in five years of live time, corresponding to an upper limit on the effective Majorana mass in the range 40Â-100 meV (50Â-130 meV). Further background rejection with auxiliary bolometric detectors could improve CUORE sensitivity and competitiveness of bolometric detectors towards a full analysis of the inverted neutrino mass hierarchy. CUORE-0 was built to test and demonstrate the performance of the upcoming CUORE experiment. It consists of a single CUORE tower (52 TeO2 bolometers of 750 g each, arranged in a 13 floor structure) constructed strictly following CUORE recipes both for materials and assembly procedures. An experiment its own, CUORE-0 is expected to reach a sensitivity to the ÃYÃY(0v) half-life of 130Te around 3Ã--1024 y in one year of live time. We present an update of the data, corresponding to an exposure of 18.1 kg y. An analysis of the background indicates that the CUORE performance goal is satisfied while the sensitivity goal is within reach. [ABSTRACT FROM AUTHOR]

Lead tungstate (PWO) crystal has a very fast response, high atomic density and high radiation hardness. Therefore, they are suitable to be used for high-energy nuclear data measurements under highbackground circumstances. Although a good electron-ion separation with a pulse shape analysis technique is essential, scintillation pulse shapes have not been observed with electron beams of a wide energy range. A singleelectron beam technique has been developed at Kyoto University Free Electron Laser (KUFEL), and electron beams of 4-38 MeV are available. During the experiments, single electron beams bombarded a PWO crystal. By using oscilloscope we observed scintillation pulses of a PWO crystal coupled with a photomultiplier tube. Measured spectra were compared with the simulation code of EGS5 to analyze scattering effects. As the result, the pulse amplitudes show good linearity and the pulse shapes are almost constant in the observed energy range. [ABSTRACT FROM AUTHOR]

The paper reports on a study of martensite transformation temperatures and inelastic properties of binary TiNi alloy with a Ni content of 50.8 at.% subjected to warm caliber rolling. It is shown that warm rolling makes possible micro- and submicrocrystalline structures in the TiNi specimens. The total inelastic deformation in the rolled specimens in torsion reaches 8.5%-9.5% (99% shape recovery) of which the shape memory effect is 5%-6%. [ABSTRACT FROM AUTHOR]

The regularities of microstructure formation in binary TiNi alloys with a Ni content of 50.2 and 50.8 at.% under warm abc pressing and isothermal (723 K) multipass caliber rolling had been studied. Microstructure composed of submicrocrystalline grains and subgrains was found after final abc pressing at 723 K with a total true strain e = 8.44. Three stages of grain structure evolution were revealed in the TiNi alloy with 50.8 at.% Ni subjected to warm rolling. At the first stage with low strains' the average grain size (d) increased due to collective dynamic recrystallization. The average grain size decreased steeply due to discontinuous and continuous dynamic recrystallization at the second and third rolling stage. Microstructure composed of micro- and submicrocrystalline grains was observed after rolling with e = 2.0. The sequences and temperatures of martensite transformations from a cubic B2 phase to rhombohedral R and monoclinic B19' martensite phases were studied in depend on the strain accumulated by samples under abc pressing and rolling. [ABSTRACT FROM AUTHOR]

Using the EBSD' SEM and TEM methods' the structure of surface layer of polycrystalline NiTi alloy samples was examined after the modification of material surface by the pulsed action of mean-energy silicon ion beam. It was found that the ion beam treatment would cause grain fragmentation of the near-surface layer to a depth 550 |¿m; a higher extent of fragmentation was observed in grains whose close-packed planes were oriented approximately in the same direction as the ion beam was. The effect of high-intensity ion beam treatment on the anisotropic behavior of polycrystalline NiTi alloy and the mechanisms involved were also examined. [ABSTRACT FROM AUTHOR]

Positron annihilation and X-ray diffraction analysis have been used to study submicrocrystalline nickel samples prepared by equal channel angular pressing. In the as-prepared samples the positrons are trapped at dislocationtype defects and in vacancy clusters that can include up to 5 vacancies. The study has revealed that the main positron trap centers at the annealing temperature of Δ T= 20°C-180°C are low-angle boundaries enriched by impurities. At Δ T = 180°C-360°C' the trap centers are low-angle boundaries providing the grain growth due to recrystallization in-situ. [ABSTRACT FROM AUTHOR]

The aim of this work is to take control on the grain size and densification of undoped K0.5Na0.5NbO3 (KNN), from micrometer to millimeter grain sizes. For this purpose, ceramics are prepared by spark plasma sintering (SPS) and conventional sintering. Their piezoelectric properties are comparatively studied. After full structural and microstructural characterizations, high electromechanical properties (kt = 45 %, kp = 30 %, Z = 20 MRay) for conventional sintering and (kt = 45 %, kp = 48 %, Z = 30 MRay) for SPS sintering are obtained. Otherwise, millimeter grains are produced by the floating zone method used for crystal growth, and their electromechanical properties are determined and compared to their homologous ceramics. Moreover, using the characteristics of the three materials, simulated electroacoustic responses of single-element transducers are compared. The results show that KNN is suitable for transducer applications. [ABSTRACT FROM AUTHOR]

The Electromagnetic Calorimeter of the CMS experiment at the LHC includes about 76000 lead tungstate (PbWO4) scintillating crystals. The detector properties must be continuously monitored in order to ensure the extreme stability and precision required. This leads to a very large volume of non-event data to be accessed continuously by shifters, experts, automatic monitoring tasks, detector configuration for trigger and data acquisition systems and offline data reconstruction programs. This paper describes the measurements taken by the Detector Control System, the calibrations, the data handling strategy and the workflow as well as the architecture of the configuration and conditions databases and the web interface to access the data. An overview is given on the experience with detector commissioning, which have allowed a system test in realistic run conditions. [ABSTRACT FROM AUTHOR]

Detailed 57Fe Mo¨ssbauer spectroscopy measurements on superconducting NaFeAs powder crystals have been performed. The 57Fe Mo¨ssbauer spectra recorded in the paramagnetic temperature range (T>TN≈46±2K) were discussed supposing Fe2+ ions are located in distorted tetrahedral (FeAs4) polyhedra. Our results reveal that the structural transition (TS ≈ 55 K) has a weak effect on the electronic structure of iron atoms while the development of the antiferromagnetic order (T ≤ TN) induces a redistribution of the charge at 57Fe nuclei. In the lowtemperature range, the spectra show a diffuse resonance absorption structure which evidences for the existence of a continuous distribution of hyperfine fields, HFe, at 57Fe nuclei. The shape of these spectra can be related to the formation of a microdomain structure or phase separation. Analysis of the resulting distributions, p(HFe), has shown that Mo¨ssbauer spectra give consistent and physically reasonable 57Fe hyperfine parameters over the whole temperature range. [ABSTRACT FROM AUTHOR]

The paper discusses the effect of the crystal grain size of materials on the micro cutting processes. The cutting process of ultra fine grain carbon steel, which consists of 0.5 μm sized grains, is compared with those of the larger grain steels. The micro cutting tests were performed to measure the cutting force with changing the cutting thickness. The cutting force of the ultra fine grain steel is larger than that of the large grain steel corresponding to the hardness change of materials. The specific cutting forces remarkably increase when the cutting thickness becomes less than 10 μm. The shear angle of the ultra fine grain steel is larger than that of larger grain steels in small cutting thickness. The uniform chip formation is also observed with fine surfaces in cutting of the ultra fine grain steel. [ABSTRACT FROM AUTHOR]

In this tutorial paper we will give a brief introduction of phase field method as a mathematical tool for describing interfaces and their motion. This method was originally developed as a model of solidification, which enabled us to simulate complicated structures like dendritic crystals easily. The principle of this method is simple and can be applicable to various situations, a few examples will be demonstrated. [ABSTRACT FROM AUTHOR]

Dynamic fracture of ductile metals is attributed to the nucleation, growth, and coalescence of voids which eventually form the fracture surface. Large-scale MD simulations are used to model void growth behavior in single crystal Cu at high strain rates. Yielding is studied for systems with various values of void fractions as well as combinations of loading conditions. The calculated yield surface of single crystal Cu for varying void fractions indicates the inability of traditional continuum models to predict void growth at high strain rates. [ABSTRACT FROM AUTHOR]

In-situ x-ray diffraction was used to study the response of single crystal iron under shock conditions. Measurements of the response of [001] iron showed a uniaxial compression of the initially bcc lattice along the shock direction by up to 6% at 13 GPa. Above this pressure, the lattice responded with a further collapse of the lattice by 15–18% and a transformation to the hcp structure. The in-situ measurements are discussed and results summarized. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Shock-induced melting in Al, Cu and Lennard-Jones single crystals was investigated employing large-scale non-equilibrium molecular dynamics (NEMD) and constant-stress Hugoniostat simulations. The atomic interactions in Cu and Al are modeled with embedded atom method potentials. The solid and liquid Hugoniot of these materials were generated for shock propagation along the low-index orientations: (100),(111) and (110). It is found that within sub-nanosecond time-scales, shock melting occurs at lower pressures (temperatures) for (110) shocks, at intermediate pressures (temperatures) for (111) and at higher pressures (temperatures) for (100) shocks. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

In situ X-ray diffraction allows the determination of the structure of transient states of matter. We have used laser-plasma generated X-rays to study how single crystals of metals (copper and iron) react to uniaxial shock compression. We find that copper, as a face-centred-cubic material, allows rapid generation and motion of dislocations, allowing close to hydrostatic conditions to be achieved on sub-nanosecond timescales. Detailed molecular dynamics calculations provide novel information about the process, and point towards methods whereby the dislocation density might be measured during the passage of the shock wave itself. We also report on recent experiments where we have obtained diffraction images from shock-compressed single-crystal iron. The single crystal sample transforms to the hcp phase above a critical pressure, below which it appears to be uniaxially compressed bcc, with no evidence of plasticity. Above the transition threshold, clear evidence for the hcp phase can be seen in the diffraction images, and via a mechanism that is also consistent with recent multi- million atom molecular dynamics simulations that use the Voter- Chen potential. We believe these data to be of import, in that they constitute the first conclusive in situ evidence of the transformed structure of iron during the passage of a shock wave. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The high strain rate behavior of multiphase, high density metallic polycrystals is studied via constitutive modeling and numerical simulation. Crystalline elasto-plasticity models are developed to account for the thermomechanical response of each bulk phase, and a cohesive zone approach is invoked to model the response of grain and phase boundaries. The following physical phenomena are captured by the bulk constitutive models: finite deformations, temperature- and pressure-dependent elasticity, nonlinear thermal expansion, slip-system level viscoplasticity with thermal softening due to increasing dislocation mobility, and dislocation accumulation in conjunction with strain hardening and the stored energy of cold working. The cohesive laws account for stress-state and temperature effects on interfacial strengths and correlate with the spall strength of the multiphase material. Numerical results are obtained from a 2D finite element implementation of the model under impact loading, in which individual phases, grains, and interfaces within a two-phase tungsten alloy are fully resolved. Effects of lattice orientations, grain morphology, and cohesive model parameters are reflected in the spall behavior and statistics associated with predicted free surface velocity profiles. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The PARIS calorimeter is an apparatus intended for the future SPIRAL2 facility in Caen, France. It will comprise a spherical shell of scintillators detectors making extensive use of LaBr3(Ce) - a relatively new material with excellent energy resolution (∼3% at 662-keV). The individual detector modules will be of a phoswich design where the fast LaBr3(Ce) crystal is optically coupled to a slower conventional crystal like NaI and the scintillation light is collected with a single photomultiplier tube. [ABSTRACT FROM AUTHOR]

Tetrabromo (piperazinium) zincate, a new metal-organic crystal has been synthesized and its single crystal grown by slow evaporation method. The grown crystal has characterized by structural, spectral, thermal, linear and nonlinear optical properties. Single crystal X-ray diffractions study reveals that grown crystal belongs to orthorhombic crystal system with space group P212121. The presence of functional groups is identified by FT-IR spectral analysis. Thermal stability of the crystal was ascertained by TG-DTA measurement. The second order harmonic generation efficiency was measured using Kurtz and Perry technique and it was found to be 1.5 times that of KDP. [ABSTRACT FROM AUTHOR]

In the present study, the PVA-PEO-EC-LiCF3SO3 polymer electrolytes are prepared using solution cast technique for different concentrations of Al2O3 ranging from 2 to 10 wt%. The study deals with the investigation of the influence of Al2O3 concentration on the electrical properties and crystallinity of the polymer electrolytes. The conductivity studies are carried out using impedance spectroscopic analysis and the variation in crystallinity is investigated using XRD technique. [ABSTRACT FROM AUTHOR]

Single-phase polycrystalline samples of Bi0.8Nd0.2-xCaxFeO3 (x = 0.0, 0.1) were synthesized by chemical coprecipitation method. X-ray diffraction patterns accompanied by Rietveld-refined crystal structure parameters reveal the phase transition of Bi0.8Nd0.1Ca0.1FeO3 with rhombohedral R3c symmetry to triclinic structure of Bi0.8Nd0.2FeO3 sample. Frequency dependence of dielectric constant (ε') and dielectric loss (tand), infers enhancement of both ε' (tanδ) in narrow band gap of Nd/Ca co-doped BFO as compare to wide band pristine BFO. [ABSTRACT FROM AUTHOR]

Phonons vibrational frequencies for Hg1-xCdxSe (x ≤ 0:5) crystalline alloys were theoretical and experimentally studied. Two simple expressions that summarize the optical modes behavior with composition were derived. Such that the behavior of the vibrational properties of II-VI and III-V semiconductors at the Γ point can be expressed as function of the product of the ionic charges (Z1Z2) and the nearest neighbor distance, d. A good agreement has been found between the observed and calculated values of the vibrational frequencies νLO for the ternary Hg1-xCdxSe alloys. Furthermore, our calculations suggest a non typical behavior of the acoustic vibrational modes similar to the one reported for HgSe. Besides, we also report the theoretical dependence of the phonon dispersion relation as function of composition. [ABSTRACT FROM AUTHOR]

We have measured time resolutions of a cylindrical CeBr3 scintillator of 1-inch in height and 1-inch in diameter coupled to two different fast photomultiplier tubes, Hamamatsu R9779 and Photonis XP20D0, as a function of applied high voltages and different settings of a Constant Fraction Discriminator ORTEC 935. The time resolution was measured using a time-delayed coincidence set-up involving a fast reference detector. The best result of 119(2) ps at 60Co energies was obtained for the CeBr3 crystal coupled to the Hamamatsu PMT. This result is comparable to the resolution of 107 ps reported for a LaBr3(Ce) crystal of the same size. For the coupling of the CeBr3 scintillator to the Photonis PMT we got the time resolution of 146(2) ps. [ABSTRACT FROM AUTHOR]

A phoswich configuration consists of LaBr3(Ce) and LaCl3(Ce) crystals optically coupled and stacked together with a common readout. Each crystal has different decay time response and different light yield which make possible the design of a high efficient gamma radiation and proton endcap detector, as a continuation of the CALIFA barrel. [ABSTRACT FROM AUTHOR]

We report here the powder X-ray diffraction and magnetic measurements of two ternary compounds GdCo0.17Sn2 and GdCu0.17Sn2 for the first time. Both the compounds crystallize in the defect CeNiSi2-type structure. The magnetic measurement reveals that GdCo0.17Sn2 and GdCu0.17Sn2 order antiferromagnetically below 16.5 K and 25 K, respectively. [ABSTRACT FROM AUTHOR]

GdRhln crystallizes in Fe2P type crystal structure with space group P62m. Magnetization measurements on bulk GdRhln sample show that the compound orders ferromagnetically with Curie temperature (Tc) of 34 K. The magnetocaloric effect (MCE) in this compound estimated from the M-H-T data was found to be 8 J/Kg K for a field change of 50 kOe. The compound shows good refrigerant capacity (RC) with a value of 282 J/Kg for the field of 50 kOe. [ABSTRACT FROM AUTHOR]

Zinc oxide and indium doped zinc oxide (ZnO:In) transparent conducting thin films were deposited on glass substrates by pulsed DC magnetron sputtering using separate Zn and In targets. The independent control of the In content in ZnO has helped us to explore the role of indium in influencing the oriented (002) growth, crystallinity, conductivity and mobility of the doped films. The lowest resistivity of ZnO:In thin film is 2.73×10-3 ohm-cm. At the optimal condition of high (002) orientation, ZnO:In films with electrical resistivity of 7.63×10-3 ohm.cm and mobility of 126.4 cm2/V.s are achieved. [ABSTRACT FROM AUTHOR]

Permanent dipole moment of various sizes of CdSe nano crystals have been theoretically investigated. Theoretical formulation of dipole moment is based upon the chemical concept of electro negativity. The dipole moment is calculated simply as the product of the magnitude of the effective charge and distance between them. We are explaining the size dependency in CdSe nano crystal by assuming a spherical model of electron distribution and the coulomb interaction i.e potential energy between the charges separated by given distance. Starks line shape is analyzed by the change in the dipole moment and found a broadening in line shape due to increase in the size of CdSe nano dacrystal. Results found are well in agreement with the published data. [ABSTRACT FROM AUTHOR]

Effect of polystyrene (PS) modification of SiO2 dielectric on the performance of copper phthalocyanine (CuPc) based OFETs was studied. Field effect mobility of holes was found to increase by one order for polystyrene modified dielectric as compared to that on unmodified SiO2. This is attributed to well connected grains and increased crystallinity of CuPc film. Significantly reduced hysteresis was found in the devices with PS/SiO2 dielectric due to almost complete absence of hydroxyl groups at the dielectric/semiconductor interface and hence reduced trap sites. [ABSTRACT FROM AUTHOR]

Metal contacts with gold on organics are an essential factor in organic electronics. The unveiled key challenge is to probe dynamic details of the microscopic evolution of the organic crystal when the atomic Au is introduced. Here, we show how the collapse of the pentacene crystal is initiated even by a few Au atoms. Our photoemission and x-ray absorption results indicate that the gentle decoupling of intra and inter-molecular π-π interactions causes the localization of the lowest unoccupied molecular orbital as well as the removal of cohesive forces between molecules, leading to the subsequent crystal collapse. [ABSTRACT FROM AUTHOR]

Nonvolatile memory devices with TiSi2 and WSi2 nanocrystals on the SiO2/Si3N4/SiO2 (ONO) and Si3N4/SiO2/Si3N4 (NON) tunnel layers were fabricated and their electrical properties were characterized. For the WSi2 nanocrystals memory, the threshold voltage shift (ΔVTH) maintained about 1.3 V at 125 °C, when program/erase (P/E) speeds were 50 ms. After P/E at ±7 V for 100 ms, ΔVTH of the TiSi2 memory with NON tunnel layer was about 0.7 V, while ΔVTH of the WSi2 memory with ONO tunnel layer was approximately 1 V after applied P/E pulse at ±8 V for 50 ms. [ABSTRACT FROM AUTHOR]

The specific heat of crystalline materials varies as T3 (Debye law) at low temperatures. Specific heat of glasses, however, does not obey Debye law and this is connected with the existence of tunneling states in glasses. This paper reports results of specific heat studies for mixed salts (NH4)xRb1-xBr of ammonium and rubidium bromides, which are crystalline materials. It is seen that specific heat of above salts does not obey Debye law. The existence of non-Debye specific heat is connected with the rotational tunneling states of NH4+ ions in above salts. [ABSTRACT FROM AUTHOR]

Molecular dynamics is used to study the response of single crystal copper target to impacts by single crystal copper at velocities in the range 1 km/s to 3 km/s. The Embedded Atom Method (EAM) potential by Foiles et al. for Cu [1] was used in the simulation. The potential and its implementation in the open source, Large-scale Atomic Molecular Massively Parallel Simulator (LAMMPS) [2] was verified by reproducing the experimental values of bulk modulus of Cu. The shock velocity (us) as a function of particle velocity (up) matches published experimental and molecular dynamic simulations results. [ABSTRACT FROM AUTHOR]