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The large difference of dielectric functions between the amorphous and crystalline phases of Ge–Sb–Te based phase-change materials (PCMs) used in memory storage devices also affects their Schottky barrier heights (SBHs) and thus their electrical device properties. Here, the SBHs of each phase of Ge2Sb2Te5, GeTe, GeSe, and SnTe are found by density functional supercell calculations. The Fermi level pinning factor S calculated for the crystalline phases (with a larger dielectric constant) is smaller than their amorphous phases, agreeing well with the empirical relationship linking SBH to a dielectric constant. The relatively large dielectric constant of crystalline PCMs arises from their resonant bonding (metavalent bonding), but their pinning factor is not always as small as empirically expected. The results are useful for optimizing the design of metal contacts for Ge–Sb–Te type phase-change memory devices.

Iron concentration is an important parameter for clinical usage of superparamagnetic iron oxide particles. Traditional T2 mapping for iron concentration measurement requires several images and long scanning time. This work proposes a method using phase characteristic of magnetic resonance imaging to analyze the magnetic field inhomogeneity caused by superparamagnetic iron oxide particles. Phantom experiments are implemented on 4.7T MRI system. Phase dependence on time of echo and iron concentration is discussed. Results validate the feasibility of measuring superparamagnetic iron oxide particle concentration by phase data at one single scanning.

The Andreev-like levels and the free energy of the spin superconductor/insulator/spin superconductor junction are obtained by using the Bogoliubov–de Gennes equation. The phase dependence of the spin supercurrents exhibits a 0–π transition by changing the barrier strength. The dependences of the critical current on the barrier strength and the temperature are also presented.

This paper investigates the effects of the spontaneously generated coherence (SGC) and incoherent pumping field on the dynamical behaviors of the dispersion and the absorption. Using a three-level Λ-type atomic medium, the influence of the relative phase between the applied fields on the transient dispersion and absorption is discussed. It is shown that the phase dependence of the dispersion and the absorption not only depend on the existence of SGC, but they depend on the existence of the incoherent pumping field as well. We show that the medium can be used as an optical switch in which the propagation of the laser pulse can be controlled by another laser field.

In this work, we made five samples of SrAl2O4:Eu2+, Dy3+, the α phase and β phase SrAl2O4:Eu2+, Dy3+ powder and pellet samples, and α phase single crystal. We have measured the emission spectra of all the samples. All the emission peaks are around 520 nm, which correspond to the transition from 4f65d1(2Eg) to 4f7(8S7/2) of Eu2+ in SrAl2O4 host. The intensity of emission of the β phase is stronger than that of the α phase. We believe that it is because the Eu2+ ions have occupied the two types of sites in the α phase SrAl2O4 host and the lifetime of the transition of Eu2+ in the A site is longer than that in the B site. This result also proves that the β phase of the material is brighter than the α phase. In addition, the β phase can be achieved by quenching technique.

Surface plasmon resonance (SPR) interferometry is reported as a novel technique for biological and chemical sensing, which employs not only the amplitude of a resonantly reflected light wave, but its phase as well. In this connection, the phase behavior under SPR has been comprehensively described by theoretical analysis, numerical simulations, and a number of experiments. Near optimum SPR conditions, a resonant phase dependence is step-like, the ‘step’ being at the reflectivity minimum. For SPR-based sensors, the slope of the ‘step’ can always be made by several orders steeper than that of the resonant reflectivity contour. The ‘step’ has been imaged by the fringe of a 2-dimensional interference pattern where one coordinate was the incidence angle, and the other was the phase. The inversion of the ‘step’ has been observed for the first time during antigen–antibody binding, when the system passes through the optimum SPR conditions. Monitoring the inversion provides for ultra-high sensitivity to an analyte while recording angular position of the ‘step’, does for dynamic range as wide as that of traditional SPR sensors. The SPR interferometry technique has confirmed theoretical findings and opened up new possibilities for (bio)chemical sensing.

The effect of the anharmonic phase dependence of the supercurrent on I-V hysteresis in a Josephson junction is studied in terms of a modified resistive model.

The erase band resulting from edge overwrite has been studied using magnetic force microscopy. Utilizing image processing techniques, we developed a method to accurately measure the width of the edge erase band. In this paper, we focus on the study of MR/thin film head recording. Our experimental results show the erase band width is strongly dependent on the relative phase of the transitions in the old and new tracks at low bit densities. As the recording density is increased, the erase band width increases and becomes independent of the phase change. The erase band width observed ranges from 0 to 0.7 /spl mu/m for a typical MR/thin film head with 4 /spl mu/m wide trailing pole.

The W values of protons in water vapour were measured for energies from 1 keV to 100 keV with uncertainties lower than 1%. To study the energy and phase dependence of W values, the W values of protons in water vapour and liquid water were calculated for energies from 0.1 keV and 10 MeV and then compared to the experimental results of this work.

Coalescence of precipitates is a common kinetic phenomenon. The phase-field method can simulate coalescence of precipitates without any ad hoc assumptions. However, independent of long range effects (e.g. lattice misfit) the method predicts a high coalescence rate when applied to systems with a high volume fraction of precipitates. We show that this is a result of ignoring the local phenomenon in the interface regions, which is an approximation adopted by many other simulation techniques. An improved coalescence rate is achieved by properly addressing this local phenomenon through introducing composition and phase dependence of diffusion mobility.

The aim of this study is to establish the structure-properties relationship of tetrathiafulvalene (TTF). After this study (1) TTF crystals with α and β phases were controllably obtained by the cast method with careful selection of the solvents, and (2) organic field-effect transistors (OFETs) of α and β phases both exhibited field-effect performance, and the performance of α phase was much better than that of β phase. The highest mobility of α phase reached 1.2cm2V−1s−1, while β phase showed the maximum mobility only about 0.23cm2V−1s−1, indicating the strong performance dependence of OFETs performance on the crystal phases.

A discussion of the evolution of the HE12 (LP02) field, and thus the role of the core in HE11-H12 (LP01-LP02) local-mode coupling for a tapered ‘doubly-clad’ lightguide as may be formed by the combination finite-cladding fibre and external medium (i.e. outer cladding) is presented. Consideration of more than one interface injects interesting novel features into the local-normal-mode viewpoint: examination of the HE12 lobe maximum and field evolution leads to the discovery of a core/cladding bounce phenomenon (related to an HE12 leaky-mode property) as well as an intriguing coupling phase dependence.

A practical method is described for the phase determination of x-ray reflections from single crystals. Considerations on the dynamical interaction in multiple diffraction and on the relative rotation of the crystal lattice with respect to the Ewald sphere reveal both experimentally and theoretically the phase dependence of the reflected intensity. Applications can be made for a direct experimental determination of phases without carrying out the complicated dynamical calculation.

Positron lifetime spectra have been obtained as a function of temperature for various solid mixtures of n-eicosane (C20H42) and n-docosane (C22H46). These compounds, when mixed in various proportions, are known1 to form at least six distinct solid phases. Positron lifetime parameters T 2 and I 2 have been measured in each of these phases and are found to exhibit both a temperature and a phase dependence. Comparison with crystallographic data reveals that t 2 variations in the n-eicosane: n-docosane system depend more strongly on the lattice dimensions a and b than on the dimension c.

In-core neutron detectors were used for noise diagnostic measurement in a commercial PWR NPP. Phase dependence versus frequency between axially placed self powered neutron detectors (SPND) exhibited linear behaviour in some cases. Correlation was found between the existence of linear phase behaviour and the power of the Unit. More thoughtful consideration showed a dependence on local power, and on overheating of the surface of fuel elements. Data extracted from conventional measurement of top of core temperature sensors and in-core SPNDs, using the conventional system for linear power production estimation showed that linear phase takes place where linear power production is over 2 MW/m. One dimensional thermohydraulic calculation pointed out that at those places the surface temperature is near or over the saturation value. Thus the appearance of linear phase versus frequency can be attributed to phenomena of local subcooled boiling and therefore its existence can be used for boiling detection in PWRs. All basic considerations had been checked beforehand in model experiments and are cited here.

For several metals like Hg, In, Ga and Tl , we show that the solid-liquid phase transition can generate large changes in the photoemission properties. The temperature or phase dependence of the yield Y(T), workfunction Φ(T), vector-ratio α(T) and the energy distribution curves (EDC) are of special interest here. Thallium shows an additional solid-solid phase transition and offers the opportunity of studying a transition between two different ordered states. Possible reasons for the observed changes at a phase transition are discussed.

Photometric properties of the lunar surface in visual and near-infrared light were studied using raw images obtained with UVVIS camera during the Clementine mission. The investigation focused on several specific regions on the lunar surface, each of which was observed by Clementine at a variety of different illumination and viewing geometries. Through these observations, the dependence of the surface brightness on the observation/illumination geometry was studied. It was shown that the disk component of this dependence, that is, the variations of brightness at constant phase angle, is different for different mare areas. The color of the lunar surface also changes with changing of the observation/illumination geometry, even if under constant phase angle. The Reiner Gamma formation displays unusual photometric properties. They are consistent with the surface being smoother than the typical mare regolith surface. The UVVIS images taken at the smallest phase angles were used to study the opposition spike, that is, the sharp increase of the surface brightness near the opposition. Steepness of the phase dependence of brightness varies over a wide range for different sites.