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Te-doped and ZnTe-doped diluted ZnSeTe samples were grown by using metal-organic chemical vapor deposition. The green lights emitted from these two samples in the photoluminescence (PL) measurement have different peak emission energies and can be attributed to different emission mechanisms. For the Te-doped sample, the PL emission band is excitation laser power independent, the lifetime of the PL emission is short, and the PL emission could be attributed to the emission originated from Te isoelectronic centers. For the ZnTe-doped sample, the energy of the green emission band is laser power dependent, the PL lifetime is much longer than the Te-doped sample, and the PL emission could be attributed to the emission from type-II ZnTe/ZnSe quantum dots. The results demonstrate that there are two different mechanisms responsible for the green PL emission in ZnSeTe system and our growth methods provide a way of selecting one of the two mechanisms for the green light emission in this system. [ABSTRACT FROM AUTHOR]

Dimensionless three-dimensional universal phase and lift force diagrams of a microbubble (or pendant drop) in static liquid on a solid surface (or orifice) are presented in this work. Microbubble dynamics has been found to play a vital role in mass, momentum, energy, and concentration transfer rates in contemporary micro- and nanosciences and technologies. In this study, dimensionless phase and force diagrams are introduced by utilizing the analytical solutions of the microbubble shape reported in the literature. It shows that phase and force diagrams can be universally specified by two dimensionless independent parameters, Bond number, and contact angle (or base radius). Based on the presence of an inflection point or neck on the microbubble surface, each diagram exhibits three regions. Growth, detachment, and entrapment of a microbubble can be described by path lines in three regions. The corresponding universal total lift forces include hydrostatic buoyancy, difference in gas, and hydrostatic pressures at the base, capillary pressure, as well as surface tension induced by the variation of circumference, which has not been treated in the literature so far. In the absence of viscous stress and Marangoni force, the total lift force equals surface tension induced by the variation of circumference. The latter can be an attaching or lifting force, depending on whether the state in the distinct regions and contact angle is less than or greater than a critical angle. The critical angle, which is slightly less than the inclination angle at the inflection point, is decreased with increasing Bond number. [ABSTRACT FROM AUTHOR]

Studies epitaxial superconducting thin films grown on buffer layers. Method of the study; Results and discussion; Conclusion.

Focuses on strontium-(aluminum-tantalum)-oxygen (O) thin films that have been deposited on magnesium-O substrates using pulsed laser deposition. Dielectric properties of the thin film ceramic samples; Application of the pulsed laser deposition technique; Overview of the in-plane epitaxy of the thin films.

Presents a study which prepared superconducting TlSr[sub2](Ca,Cr)Cu[sub2]O[sub7] thin films with zero resistance temperature via laser ablation and thallium diffusion. Indications of x-ray diffraction patterns; Information on the third harmonic response measured; Reaction between thallium vapor and precursor film.

Focuses on a study which investigated the temperature and magnetic field dependence of critical current density for yttrium barium copper oxide thin films. Discussion on the importance of the critical current density in electronic applications of high-temperature superconductor thin films; Details of the experimental procedure; Findings from x-ray diffraction analysis.

The spontaneous surface luminescence properties of InGaN/GaN quantum structure lattice (QSL) are reported. The QSL consists of a two-dimensional array of InGaN/GaN quantum boxes (QBs) arranged in a rectangular pattern of 200nm periodicity. The measured angular dependent photoluminescence (PL) spectra show a strong dependence on the in-plane Bragg diffractions between QBs. The maximum PL intensity of the InGaN/GaN QSL array that fulfill the Bragg condition points in the normal direction of the sample surface with a narrow radiation angle of ~ ±12°. In addition, a small side lobe is also shown at ±40°. For the QSL sample that does not fulfill the Bragg diffraction condition, the radiation pattern shows a conventional cosine distribution. The finite-difference time-domain numerical analysis confirms that the lowest order and higher order Bragg diffractions between QBs determine the main and the small side lobe of the radiation pattern measured in QSLs, respectively. [ABSTRACT FROM AUTHOR]

The dielectric properties of membrane and cytoplasm of cells were commonly derived using the experimental electrorotation spectra, which are proportional to the spectra of the imaginary part of the Clausius-Mossotti factor (Ki). However, it was found in this study that the cell properties thus derived do not agree with those derived using the experimental spectra of the real part of the Clausius-Mossotti factor (Kr). Both the Kr and Ki spectra are required simultaneously for deriving appropriate cell dielectric properties. Also the membrane and cytoplasm conductivities decrease, while the membrane and cytoplasm permittivities remain relatively unchanged, as the medium conductivity decreases. [ABSTRACT FROM AUTHOR]

An assembly of soft x-ray pulse height analyzer system, based on silicon drift detector (SDD), has been successfully established on the experimental advanced superconducting tokamak (EAST) to measure the spectrum of soft x-ray emission (E=1–20 keV). The system, including one 15-channel SDD linear array, is installed on EAST horizontal port C. The time-resolved radial profiles of electron temperature and Kα intensities of metallic impurities have been obtained with a spatial resolution of around 7 cm during a single discharge. It was found that the electron temperatures derived from the system are in good agreement with the values from Thomson scattering measurements. The system can also be applied to the measurement of the long pulse discharge for EAST. The diagnostic system is introduced and some typical experimental results obtained from the system are also presented. [ABSTRACT FROM AUTHOR]

Based on the high surface sensitivity of piezoelectric polarization of strained nitride semiconductors, surface functionalized nitride light emitting devices (LEDs) provide an excellent opportunity for the development of biological sensors. To demonstrate our working principle, a probe chip based on In0.22Ga0.78N/GaN multiple quantum wells has been constructed and exposed to target DNA solutions, matched and/or mismatched, with different concentrations. The pronounced changes of photoluminescence spectra as well as Raman scattering A1(LO) spectra in matched target DNA clearly illustrate the feasibility of our proposed mechanism. The results shown here open up a new possibility for the application of nitride LEDs in biosensor engineering. [ABSTRACT FROM AUTHOR]

The resistive bolometer system has been successfully employed on experimental advanced superconducting tokamak for the first time to measure the radiated power of plasma. The bolometer detectors are based on 4 μm thick Pt absorbers deposited on 1.5 μm thick SiN membranes. The system consists of 3 cameras with a total of 48 channels. The detector and the system setup are described in detail. The detector calibration and typical measurement results are presented as well. [ABSTRACT FROM AUTHOR]