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The surface optical (SO) phonon replica in photoluminescence (PL) spectroscopy of nitride nanowires (NWs) was theoretically investigated in this study. The dispersive relationships of SO phonon mode in anisotropic wurtzite (WZ) and isotropic zinc-blende (ZB) crystal structure NWs with circular and square cross sections (CSs) were derived within the framework of the dielectric continuum model. Based on the energy and momentum conservation laws, a constraint relationship between the frequency and wave-number was constructed for SO phonon-assisted excitonic PL spectra in the NW structure. By combining the dispersive and constraint relationships, the frequency and wave-number of the SO phonon replica in the PL spectra could be determined. The WZ and ZB crystal structures of nitride semiconductor were considered. The influences of surface factors including the CS shape, dielectric medium, and environment temperature on the frequency and photon wavelength of the band-edge emission of the SO phonon replica were studied in detail. Numerical results reveal that the crystal structure, surface factors, and environment temperature greatly affect the frequency and photon wavelength of the band-edge emission of the SO phonon replica. The calculated results for the photon wavelength agree well with the experimental values of the SO phonon replica in AlN NWs. The results of the dielectric effect obtained here are also supported by previous experimental and theoretical results for nitrides and other semiconductor NWs. The present theoretical scheme and numerical results can be used to analyze and design the SO phonon replica in PL spectra of nanostructures. [ABSTRACT FROM AUTHOR]

A new evolution pattern for broadband laser excited stimulated Raman back-scattering (BSRS) in the kinetic regime is proposed by numerical simulations. It is found that the change of coherence of different frequency beamlets will cause the fluctuation of laser intensity, generating an ensemble of random intensity pulses and leading to an intermittent excitation of BSRS. The kinetic inflation and intense amplification of scattered light are observed due to the synergism between these pulses, which cause a burst of instantaneous reflectivity. The synergistic effect is highly bandwidth-dependent. Under the bandwidth similar to the existing broadband laser facilities, these bursts will generate over-expected scattered light and hot electrons. Fortunately, a large bandwidth laser can still inactivate the synergy mechanism and mitigate the scattering effectively. We formulated a theoretical model to predict the inactivate point, and the calculation Δ ω / ω 0 = 2.57 % is in good agreement with the numerical results. [ABSTRACT FROM AUTHOR]

Shock-induced opacity in Gd3Ga5O12 (GGG) single crystals is investigated by transmission/ emission measurements at 16 wavelengths (400-800 nm), as well as complementary particle velocity measurements at 1550 nm, in the pressure range of 47-211 GPa. Optical transmission spectra through the shocked samples are measured with a in-situ, shock-generated light source, and the resultant extinction coefficients of different wavelengths and shock pressures obtained. As shock strength increases, the optical opacity of the shocked GGG increases and peaks at 75 GPa (the transparent-opaque transition), drops at 75-100 GPa (the opaque-transparent transition), and then increases again. The transparency recovery coincides with a solid-solid phase transition. The microstructure changes associated with the solid-solid phase transition and plastic deformation most likely cause the loss and recovery of transparency. GGG can be useful as a high pressure window for laser velocimetry (1550 nm) or optical pyrometry (400-800 nm) in the ranges of 100-140 GPa and 80-120 GPa, respectively. [ABSTRACT FROM AUTHOR]

Refractive indices of [111] Gd3Ga5O12 single crystals under shock compression are investigated with planar impact and high-speed laser velocimetry, in the pressure range of 100-290 GPa. The refractive index, n, at 1550 nm is obtained as a function of shock pressure or density (q). n increases as pressure increases from 106 GPa to 201 GPa, and then drops sharply as a result of shock-induced melting; the n - q relation is linear for the high pressure solid phase. We also establish the true particle velocity-apparent velocity relation for velocity correction. [ABSTRACT FROM AUTHOR]

The spin-mixing conductance (SMC) is an essential parameter for ferromagnetic-insulators-based spintronics devices. Here, we study the influence of device boundary on local spin transport properties in platinum (Pt)/yttrium iron garnet (YIG) films by reducing the lateral size of the devices. An obvious fluctuation of spin Hall magnetoresistance, Gilbert damping coefficient, and effective spin Hall angle with restricting the size of YIG films has been found at room temperature. By employing both harmonic and current-induced spin-torque ferromagnetic resonance measurements, we have found a negligible fluctuation of both the imaginary part of SMC and effective magnetization with varying the geometric size of devices. In contrast, the real part of SMC at the Pt/YIG interface has been rigidly altered. Our results show that the SMC dramatically depends on the boundary effect from Ar+-ion milling. [ABSTRACT FROM AUTHOR]

Serpentine chain C60 phases were observed in scanning tunneling microscopy (STM) images of C60 layers on zinc phthalocyanine (ZnPc) or pentacene covered Ag(111) and Au(111) surfaces. This low-density, quasi-one-dimensional organization contrasts starkly with the close-packed hexagonal phases observed for C60 layers on bare metal substrates. STM was employed to perform a detailed investigation of these chain structures for C60/ZnPc/Ag(111) heterolayers. Motivated by the similarity of these chain phases, and the chain and stripe organization occurring in dipole-fluid systems, we investigated a model based on competing van der Waals attractions and electrostatic repulsions between C60 molecules as an explanation for the driving force behind these monolayer phases. Density functional theory (DFT) calculations revealed significant charge transfer to C60 from the Ag(111) substrate, through the intervening ZnPc layer, inducing electrostatic interactions between C60 molecules. Molecular dynamics simulations performed with attractive van derWaals interactions plus repulsive dipole-dipole interactions reproduced the C60 chain phases with dipole magnitudes consistent with DFT calculations. [ABSTRACT FROM AUTHOR]

Different from the extensive experimental investigations into the thermoelectric (TE) properties of the bulk IV–VI compounds, less attention has been paid to the TE properties of the monolayer IV–VI compounds. Here, we consider the TE transport properties including the Seebeck coefficient, electronic conductance, thermal conductance, power factor, and figure of merit Z T of the undoped and Bi-doped GeS monolayers. Our results show that for both the undoped and Bi-doped monolayers the anisotropy is widely observed in all their TE properties, and the maximum Z T at a certain temperature along the armchair direction is much greater than that along the zigzag direction. Moreover, Bi doping can lead to an increase of the maximum Z T , and there are more Z T peaks appearing near the zero chemical potential. This indicates that the Bi-doped GeS monolayer can work as a TE material at a lower bias voltage, and especially along the armchair direction it can work at zero bias voltage, which obviously strengthens the reliability of the TE devices. As the temperature increases, the maximum Z T will be uniformally increased along the armchair and zigzag directions for both the undoped and Bi-doped GeS monolayers. In the temperature scope from 300 to 800 K, the maximum Z T along the armchair direction of the Bi-doped GeS monolayer will increase from 3.39 to 4.85, which indicates that this Bi-doped GeS monolayer is a promising TE material in a wide-temperature zone. As an application, we have designed the GeS-based TE couples and found that their efficiencies can be greater than 27 % at large temperature differences. This research should be an important guidance for designing a low-voltage, wide-temperature-scope, and high-stability TE device. [ABSTRACT FROM AUTHOR]

In order to calibrate the error model coefficients of the platform inertial navigation system tested on the precision centrifuge accurately, the error sources of the precision centrifuge are analyzed first. Combined with the error models of the inertial instruments (liquid floated gyroscope and quartz accelerometer) in the platform inertial navigation system, the calibration model of the platform inertial navigation system tested on the centrifuge, i.e., the state equation and observation equation, is deduced. The Euler angles of the platform, the error model coefficients of the inertial instruments, the installation errors of the instruments, and especially the centrifuge errors are taken as the state variables of the system, and the outputs of the accelerometers, and the Euler angles of the platform are taken as the observation variables. Then, the calibration scheme of the platform inertial navigation system tested on the centrifuge is designed, and the corresponding simulation analysis is carried out. The error model coefficients of the instruments are estimated by the extended Kalman filter. The influence of centrifuge errors on the calibration results is analyzed, which verified that the proposed method can effectively eliminate the influence. Thereby, the calibration accuracy of the inertial navigation platform system is improved, especially high-order error coefficients. [ABSTRACT FROM AUTHOR]

In this paper, we present an explicit Darboux transformation of the generalized mixed nonlinear Schrödinger (GMNLS) equation. The compact determinant representation of the n -fold Darboux transformation of the GMNLS equation is constructed and the n th-order solution is built. We further prove that only the even-fold Darboux transformation and the even-order solution of the GMNLS equation can, respectively, be reduced to the Darboux transformation and solution of the Kundu–Eckhaus equation. Furthermore, two different kinds of explicit one-soliton solutions of the GMNLS equation are constructed and discussed. [ABSTRACT FROM AUTHOR]

The structure at the atomic scale and optical properties of GaN-based green light-emitting diodes (LEDs) before and after in situ degradation were investigated by spherical aberration corrected scanning transmission electron microscopy and temperature-dependent micro-photoluminescence. Indium (In) interstitial atoms existed in the degraded sample, due to the small-bond-energy In atoms deviating from their normal lattice position, caused by the relaxation of the InGaN well. Both the peak wavelengths of the original and degraded green LEDs had similar temperature-dependent behaviors, due to the localization states in the InGaN well. These wavelengths indicate that the degradation had little influence on the localization states. However, the emission peak of the degraded green LED redshifted by 1.6 nm at 300 K, and the integrated intensity decreased by 36.8%, compared to the peak and intensity of the original sample, respectively. Based on first-principles calculations, the calculated bandgap for the relaxation of the InGaN well was small. Therefore, the wavelength redshifted, and the luminous efficiency of the green LED decreased after degradation. These features are attributed to a decreased bandgap due to the relaxation of the InGaN well; increased defect density, resulting from In interstitial atoms; and an increase in the InGaN well thickness. [ABSTRACT FROM AUTHOR]

The spin currents generated by spin–orbit coupling in nonmagnetic metals or at interfaces with broken inversion symmetry are particularly important for devices with extraordinary performance. We have investigated the spin–orbit torques (SOTs) in Ru/Fe/HfO2 heterostructures with weak perpendicular magnetic anisotropy. Although the bulk spin Hall effect (SHE) of the Ru layer is smaller than that of Pt, Ta, or W, robust SOT-induced magnetization switching can also be realized. Through nonadiabatic harmonic measurements, the effective spin Hall angle in Ru/Fe/HfO2 heterostructures is calculated to be −0.045. We have explored the mechanisms of spin current generation, which could stem from the Ru/Fe interfaces other than the weak bulk SHE of Ru. Our results suggest the spin current generation mechanisms in ferromagnet/nonmagnetic metal heterostructures remain to be further explored. [ABSTRACT FROM AUTHOR]

Reciprocal transformations are introduced for two super Camassa–Holm (CH) equations. Under these transformations and appropriate changes of dependent variables, the super CH equation, proposed by Geng et al. [Stud. Appl. Math. 130, 1 (2013)], is converted to a negative member of the super Korteweg–de Vries (KdV) hierarchy studied by Geng and Wu in 2010 [Appl. Math. Lett. 23, 716 (2010)], while the other super CH equation, due to Zhang and Zuo [J. Math. Phys. 52, 073503 (2011)], is related to a new super KdV hierarchy. In the latter case, algebraic properties of this new super KdV hierarchy are established, including Hamiltonian operators, a recursion operator, and conserved quantities. [ABSTRACT FROM AUTHOR]

Room temperature ferromagnetic Zn0.95Co0.05O thin films with (002) preferential orientation have been successfully deposited by pulsed laser deposition at different oxygen partial pressures on n-type (100) silicon substrate. A maximum saturation magnetization of 0.86 μB/Co was achieved at room temperature at 5 × 10-6 Torr oxygen partial pressure. HRTEM and XPS results indicate that the observed ferromagnetism is not due to metallic Co microclusters in the thin films. Oxygen vacancies in the films were detected from photoluminance characterization, which showed a significant effect on the ferromagnetic behavior. By changing the amount of oxygen vacancies through adjusting the oxygen partial pressure during deposition and post-deposition annealing, the ferromagnetic behavior of the thin films can be tuned significantly. This implies that the oxygen vacancies, which contribute to the bound magnetic polarons model and RKKY indirect interaction, are the likely cause of this ferromagnetism. [ABSTRACT FROM AUTHOR]

Perovskite-type transparent and conductive oxide films, Sb-doped SrSnO3 (SSSO), were grown on SrTiO3(001) substrates by the pulsed laser deposition method. It is revealed that the films can be grown at relatively lower temperatures and show high single crystallinity with a cubic perovskite structure with lattice constant of 4.036 Å. These films show good optical transmittance in the visible range, with the direct allowed band gap of 4.53 eV, and behave as an n-type semiconductor with resistivity of 23 mΩ cm at room temperature. The effect of growth temperature on structural, electrical, and optical properties of the SSSO films was probed, and a diode based on n-SSSO/p-La0.67Ca0.33MnO3 structure was also demonstrated. [ABSTRACT FROM AUTHOR]

Room temperature ferromagnetic Zn0.95Co0.05O thin film with (002) preferential orientation has been deposited by pulsed laser deposition at different substrate temperatures on n-type (100) silicon substrate. A maximum saturation magnetization of 0.86μB/Co was achieved at room temperature. High-resolution transmission electron microscope and x-ray photoelectron spectroscopy results indicate that this ferromagnetism behavior is not due to Co microclusters in the thin film. Zinc interstitials, oxygen vacancies, and lattice defects induced by low substrate deposition temperature show a significant effect on ferromagnetic behavior. By changing the substrate deposition temperature to control the amount of zinc interstitials, oxygen vacancies, and lattice defects, ferromagnetism can be tuned significantly as well, which is a direct evidence that these defects contributed to the ferromagnetism in ZnO:Co thin films. [ABSTRACT FROM AUTHOR]

Barium zirconate titanate Ba(Zr0.2Ti0.8)O3 (BZT) thin films on La0.7Sr0.3MnO3 (LSMO)-coated Si and Pt/Ti/SiO2/Si substrates have been prepared by pulsed laser deposition and crystallized in situ at 650 °C. Four capacitor types of LSMO/BZT/LSMO/Si, Pt/BZT/LSMO/Si, Pt/BZT/Pt/Si, and Pt/BZT/LSMO/Pt/Si were prepared to investigate the structural and dielectric properties, tunability, and figure of merits. Among them, the high (100)-oriented BZT films were grown on the (100)-textured LSMO and (111)-textured Pt electrodes. The results show that the LSMO/BZT/LSMO/Si has the highest dielectric constant of 555 and Pt/BZT/LSMO/Pt/Si has the highest tunability of 73% at 1 MHz. The high dielectric constant and tunability have been attributed to the (100) texture of the LSMO bottom layer leading to the decrease of the thickness of the interface of the dead layer. [ABSTRACT FROM AUTHOR]

Visible and infrared photoluminescence was observed from AlN:Er films grown by reactive radio-frequency magnetron sputtering under different powers. X-ray diffraction indicates that the films have a c-axis oriented hexagonal wurtzite structure with an average crystallite size of about 59–83 nm and a strain of about (1.12–1.69)×10-3. Green emissions (∼540 and 558 nm) from the AlN:Er films are due to the intra-4fn transition of Er3+ from 2H11/2 and 4S3/2 to 4I15/2, and infrared (∼1535 nm) emissions correspond to 4I13/2 to 4I15/2 transitions. Increasing the sputtering power results in larger grain size, lower strain, and enhancement of the luminescence intensity. [ABSTRACT FROM AUTHOR]

Presents a detailed characterization of the ordered structure in silicon-doped Ga[sub0.51]In[sub0.49]P. Influence of silicon doping on the ordering in GaInP layers; Analysis of undoped layers grown at various substrate temperatures; Relationships between photoluminescence peak energy and electron concentration of silicon-doped samples at room temperature.

Presents information on a study which examined a carrier current balance model for surface photovoltage. Details of the theoretical model employed in the study; Discussion; Conclusion.

Deals with a study which investigated the effect of strain-induced band-gap modulation in a GaAs/AlGaAs multiple-quantum-well structure with the wells located at various depths in the structure. Background to the study; Experimental procedures; Results and discussion.

Presents a study which examined highly carbon-doped gallium arsenide epilayers grown by low-pressure metalorganic vapor phase epitaxy using high-resolution x-ray diffraction. Information on carbon-doping; Methodology; Results.

Focuses on a study which presented a photoluminescence (PL) analysis of gallium indium phosphide/gallium arsenide single-quantum well structures grown by metal-organic vapor-phase epitaxy. Description of the sample and procedure; Estimation of the growth temperature dependent conduction and valence band discontinuity of the heterojunction; Results of x-ray diffraction measurements and simulations.

Deals with a study that investigated the use of thin film technology to introduce controllable and thermally stable stress into semiconductor heterostructures. Reason for the reproducibility and controllability of the induced stress in the structure; Dependence of the stability of the stress; Interrelationship between the photoelastic waveguide characteristics and the stress.

Presents a study that investigated gallium compound interfaces grown by low-pressure metalorganic vapor phase epitaxy at various temperatures and in different structures. Use of photoluminescence method; Results of the examination on gallium compound using x-ray diffraction measurements and simulations with dynamical theory.

Studies the use of high resolution x-ray diffraction thin indium arsenide and gallium arsenide layers grown on InP substrates by low-pressure metalorganic vapor-phase epitaxy. Growth parameter and structural parameter of the investigated samples; Superlattice periods determined from the observed satellites separations; Enlargement of an experimental rocking curve of sample IX in the vicinity of the zeroth-order peak.

Mechanisms and influence factors of surface optical (SO) phonon-mode-assisted exciton photoluminescence (PL) spectroscopy in quasi-1-dimensional (Q1D) nitride nanostructures remain a subject of debate. In this work, using momentum and energy conservation laws, a constraint relationship for the frequency and wave number of SO phonon-mode-assisted exciton PL is established. Using the dispersion relationships of SO modes in anisotropic wurtzite nanowires, the frequency and wave number of SO-mode-assisted exciton PL emission are determined. The present theoretical scheme and numerical results not only explain a current experimental discrepancy but could also be used to predict and design exciton PL spectroscopy with SO phonon modes in Q1D nanostructures. [ABSTRACT FROM AUTHOR]

Dy doped α-SiAlON ceramics prepared by the hot-pressing method show a high optical transmittance value, >70%, in the infrared region of 1.5–4.5 μm. First principles calculations have been carried out to reveal the underlying transparency mechanism. It is found that the valence shell of doped Dy atoms interacts strongly with the doping states of α-SiAlON, resulting in the increase in the optical gap from 0.4 to 1.1 eV, which suppresses the photoabsorption in the wavelength region longer than 1.0 μm and leads to the good transparency property. The calculated optical transmission spectra are in good agreement with the corresponding experiments. [ABSTRACT FROM AUTHOR]

We report that (La0.07Ba0.93)SnO3 films grown epitaxially on SrTiO3(001) substrates by laser ablation at 760 °C show a cubic perovskite structure of lattice constant 4.121 Å, excellent optical transmittance in the visible range, and a weak metallic behavior with low resistivity of about 4 mΩ cm within 10–300 K. The transparent perovskite oxide films are n-type conductors, with carrier concentration and mobility at room temperature of about 2×1021 cm-3 and 0.69 cm2/V s, respectively, and a direct allowed band gap of 4.02 eV. The effect of deposition temperature on structural, optical, and electric properties of the Sb-doped Ba(Sn0.93Sb0.07)O3 films was also demonstrated. [ABSTRACT FROM AUTHOR]

We have compared the spin orbit torque (SOT) induced magnetization switching in Pt/Co/Pt/ Y3Fe5O12 (YIG) and Pt/Co/Pt/SiO2 multilayers. The critical switching current in Pt/Co/Pt/YIG is almost half of that in Pt/Co/Pt/SiO2. Through harmonic measurements, we demonstrated the enhancement of the effective spin Hall angle in Pt/Co/Pt/YIG. The increased efficiency of SOT is ascribed to the nonequilibrium proximity effect at the Pt/YIG interface, which suppresses the spin current reflection and enhances the effective spin accumulation at the Co/Pt interface. Our method can effectively reduce the switching current density and provide another way to modulate SOT. [ABSTRACT FROM AUTHOR]

Design of head interconnect is one of the important issues for hard disk drives with higher data rate and storage capacity. The impedance of interconnect and electromagnetic coupling influence the quality level of data communication. Thus an insightful study on how the trace configuration affects the impedance and crosstalk is necessary. An effective design approach based on Taguchi's robust design method is employed therefore in an attempt to realize impedance matching and crosstalk minimization with the effects of uncontrollable sources taken into consideration. [ABSTRACT FROM AUTHOR]

A Darboux transformation is constructed for the generalized Hirota-Satsuma coupled KdV system and the result is compared with the recent work of Geng and his collaborators [X. G. Geng et al., Phys. Rev. E 79, 056602 (2009) and X. G. Geng and G. L. He, J. Math. Phys. 51, 033514 (2010)]. It is shown that our Darboux transformation may be applied to three interesting reductions of the general system. In addition, the iteration of this Darboux transformation is worked out, and some solutions to the associated systems are obtained. [ABSTRACT FROM AUTHOR]

Shubnikov–de Haas (SdH) oscillations and the quantum Hall effect (QHE) can give insights into quantum oscillations of charge carriers. We report the SdH oscillations and QHE of magnetically doped topological insulator FexBi2−xSe3 crystals, in which the lattice constant c decreases with the increasing dopant concentration but increases when x is greater than 0.08. From the fitting of low-temperature magnetoresistance data to the Lifshitz–Kosevich formula, the effective mass of the carriers and the Dingle temperature of the samples were extracted and show a similar trend of change as the lattice constant. A constant step size of 1/Rxy observed during Hall measurements at low temperatures implies two-dimensional-like transport behavior associated with the layered structure of the doped Bi2Se3 samples. Two-dimensional and three-dimensional charge carrier densities were calculated, and the latter had a similar trend of change as the lattice constant. A systematic study of the changes in all these properties with increasing dopant concentration suggests that they are highly correlated. [ABSTRACT FROM AUTHOR]

Magnetic skyrmions are attracting considerable interest in scientific research and practical applications. Recently, a novel phenomenon was observed in which a skyrmion bubble lattice could be induced by a slightly tilted in-plane magnetic field in a multilayer film. In this article, the formation process of a skyrmion bubble lattice was investigated by micromagnetic simulation considering the Dzyaloshinskii–Moriya (DM) interaction and distribution of magnetic anisotropy. The exchange field that prevents the reversal of moments was minimized when the magnetic moments were aligned by a slightly tilted in-plane magnetic field. Many small reversed domains were formed in the regions where the demagnetization field conquers the anisotropy field after the removal of the external field and developed into a stable skyrmion bubble array. The DM interaction has an obvious influence on the size and precise moment structure of the stable skyrmion bubbles but has little effect on the nucleation of reversed domains. [ABSTRACT FROM AUTHOR]

To investigate light emission and dynamic deformation behaviors, sapphire (single crystal Al2O3) samples with three crystallographic orientations (a, c, and r-cut) were shock-compressed by the planar impact method, with final stress ranges from 47 to 65 GPa. Emission radiance and velocity versus time profiles were simultaneously measured with a fast pyrometer and a Doppler pin system in each experiment. Wave profile results show anisotropic elastic-plastic transitions, which confirm the literature observations. Under final shock stress of about 52 GPa, lower emission intensity is observed in the r-cut sample, in agreement with the previous report in the literature. When final shock stress increases to 57 GPa and 65 GPa, spectral radiance histories of the r-cut show two stages of distinct features. In the first stage, the emission intensity of r-cut is lower than those of the other two, which agrees with the previous report in the literature. In the second stage, spectral radiance of r-cut increases with time at much higher rate and it finally peaks over those of the a and c-cut. These observations (conversion of intensified emission in the r-cut) may indicate activation of a second slip system and formation of shear bands which are discussed with the resolved shear stress calculations for the slip systems in each of the three cuts under shock compression. [ABSTRACT FROM AUTHOR]

Love mode surface acoustic wave (SAW) sensors have been recognized as one of the most sensitive devices for gravimetric sensors in liquid environments such as bio sensors. Device operation is based upon measuring changes in the transmitted (S21) frequency and phase of the first-order Love wave resonance associated with the device upon on attachment of mass. However, temperature variations also cause a change in the first order S21 parameters. In this work, shallow grooved reflectors and a "dotted" single phase unidirectional interdigitated transducer (D-SPUDT) have been added to the basic SAW structure, which promote unidirectional Love wave propagation from the device's input interdigitated transducers. Not only does this enhance the first-order S21 signal but also it allows propagation of a third-order Love wave. The attenuation coefficient of the third-order wave is sufficiently great that, whilst there is a clear reflected S11 signal, the third-order wave does not propagate into the gravimetric sensing area of the device. As a result, whilst the third-order S11 signal is affected by temperature changes, it is unaffected by mass attachment in the sensing area. It is shown that this signal can be used to remove temperature effects from the first-order S21 signal in real time. This allows gravimetric sensing to take place in an environment without the need for any other temperature measurement or temperature control; this is a particular requirement of gravimetric biosensors. [ABSTRACT FROM AUTHOR]

The ion kinetic effect on the formation of intense laser-driven collisional shock waves is investigated via hybrid fluid-particle-in-cell simulations. It is found that the ion heat flux dominates the shock formation, which is considerably larger than the electron heat flux in the shock region. The rise of the temperature due to the laser energy deposition drives a heatwave into the overdense plasma, creating an electron–ion energy exchange zone between the critical surface and heat wave front. The heated ions, which are generated at the electron–ion energy exchange zone via the friction force, are found to travel to the high-density region and cause a tail distribution gain. Despite the small quantity, the heated tail ions contribute most of the ion heat flux during the shock formation. Additionally, as the electron heat flux decreases, the population of the heated tail ions is reduced, leading to a fall in the ion heat flux. This results in the delay or even suppression of the shock formation, because the ions are in a non-equilibrium state in the vicinity of the shock region, the ratio of the downstream ion temperature to the upstream ion temperature tends to a modestly decrease in comparison to the theory. The study provides a clear picture of the formation process of laser-driven shock waves. [ABSTRACT FROM AUTHOR]

High-speed tracking of hot and molten microparticles in motion provides rich information about burning plasmas in magnetic fusion. An exploding-wire apparatus is used to produce moving high-temperature metallic microparticles and to develop four-dimensional (4D) or time-resolved 3D particle tracking techniques. The pinhole camera model and algorithms developed for computer vision are used for scene calibration and 4D reconstructions. 3D positions and velocities are then derived for different microparticles. Velocity resolution approaches 0.1 m/s by using the local constant velocity approximation. [ABSTRACT FROM AUTHOR]

In this paper, a Riemann–Hilbert approach to a two-component modified short-pulse (mSP) system on the line with zero boundary conditions is developed. A parametric representation of the solution to the related Cauchy problem is obtained. Four nonlocal integrable reductions, namely, the real reverse space-time nonlocal focusing and defocusing mSP equations and the complex reverse space-time nonlocal focusing and defocusing mSP equations, are studied in detail. For each case, soliton solutions are presented, and, unlike their local counterparts, the nonlocal equations exhibit certain novel properties induced by the impact of nonlocality. [ABSTRACT FROM AUTHOR]

The effects of MoO3 molecular doping in poly(3,4-ethylenedioxythiophene):poly(stylenesulfonate) (PEDOT:PSS) on the chemical structure and, in turn, on the carrier collection efficiency of c-Si/PEDOT:PSS heterojunction solar cells are demonstrated. Scanning electron microscopy revealed that the hydrophilic PSS polymer chain was intercalated into the interlayer van der Waals gap of MoO3 flake sheets, which modified the chemical structure of PEDOT:PSS. MoO3 exhibited intense photoluminescence in the 350-550 nm region, which enhanced the carrier collection efficiency of c-Si/PEDOT:PSS heterojunction solar cells with no significant changes. These findings suggest that the intense photoluminescence of MoO3 and its light wavelength conversion contribute to the increased carrier collection efficiency. [ABSTRACT FROM AUTHOR]

The N = 2 supercomformal transformations are employed to study supersymmetric integrable systems. It is proved that two known N = 2 supersymmetric Harry Dym equations are transformed into two N = 2 supersymmetric modified Korteweg-de Vries equations, thus are connected with two N = 2 supersymmetric Korteweg-de Vries equations. [ABSTRACT FROM AUTHOR]

Darboux transformation is constructed for a third-order spectral problem. By proper reduction, a Darboux transformation for a long-short wave model is obtained. Furthermore, a closed multi-soliton solution formula is found for this equation. [ABSTRACT FROM AUTHOR]

The supersymmetric analog of the reciprocal transformation is introduced. This is used to establish a transformation between one of the supersymmetric Harry Dym equations and the supersymmetric modified Korteweg-de Vries equation. The reciprocal transformation, as a Bäcklund-type transformation between these two equations, is adopted to construct a recursion operator for the supersymmetric Harry Dym equation. By proper factorization of the recursion operator, a bi-Hamiltonian structure is found for the supersymmetric Harry Dym equation. Furthermore, a supersymmetric Kawamoto equation is proposed and is associated with the supersymmetric Sawada-Kotera equation. The recursion operator and odd bi-Hamiltonian structure of the supersymmetric Kawamoto equation are also constructed. [ABSTRACT FROM AUTHOR]

Due to the gradual depletion and excessive consumption of fossil fuels and the resulting environmental problems, increasing attention has been paid to the utilization of the renewable energy sources such as solar energy, etc. The development and performance investigation of a photovoltaic-powered refrigerator is presented in the paper. The field performance test results show that the refrigerator can work well in Shanghai area and the lowest temperature in the freezer can reach near -15 °C and the power consumption is also reasonable. Furthermore, the energy flow of the system and applicability of it to different climatic regions have been analyzed and discussed. It can be concluded that the performance of the refrigerator is very stable and it can serve for perishable food storage, vaccine, and drug depositing at low temperatures in the remote area and it can even be used as the electrical appliance in “zero-energy” building. [ABSTRACT FROM AUTHOR]

The mean value of a quantity in an equally weighted wave packet was recently found in the classical limit to be the Feje´r average of partial sums of Fourier series expansion of the classical quantity, and the number of stationary states in it is equal to that of partial sums. The incompleteness of the Feje´r average in representing a classical quantity enables us to define a classical uncertainty relation which turns out to be the counterpart of the quantum one. In this paper, two typical quantum systems, a harmonic oscillator and a particle in an infinite square well, are used to illustrate the above-mentioned points. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

By pressure demagnetization, take iron as an example, we mean either that, given an external magnetic field under a certain temperature, the magnetization becomes weaker as the pressure increases, which can be referred to as pressure demagnetization during magnetization, or that when external field is dropped to zero, the iron has residual magnetization or remanence, and the residual magnetization becomes weaker as the pressure increases as well, which can be referred to as pressure demagnetization in remanence. In order to account for the pressure demagnetization, we demonstrate that, though magnetic work has two equivalent forms in electromagnetism, only one form is proper in thermodynamics in general. [ABSTRACT FROM AUTHOR]