Electron image series reconstruction of twin interfaces in InP superlattice nanowires

The twin interface structure in twinning superlattice InP nanowires with zincblende structure has been investigated using electron exit wavefunction restoration from focal series images recorded on an aberration-corrected transmission electron microscope. By comparing the exit wavefunction phase with simulations from model structures, it was possible to determine the twin structure to be the ortho type with preserved In-P bonding order across the interface. The bending of the thin nanowires away from the intended 110 axis could be estimated locally from the calculated diffraction pattern, and this parameter was successfully taken into account in the simulations.     

Studies on photoinduced effects in pulse-electrodeposited Ag/Hg-1212/CdSe hetero-nanostructures

Metal/superconductor/semiconductor (Ag/Hg-1212/CdSe) hetero-nanostructures have been fabricated using pulse-electrodeposition technique and are characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy (SEM) studies. The junction capacitance of Ag/Hg-1212, Hg-1212/CdSe and Ag/Hg-1212/CdSe heterojunctions is measured in dark and under laser irradiation at room temperature. The nature of the junction formed and built-in-junction potentials were determined. The increase in carrier concentration across the junction due to photo-irradiation has been observed.     

Electronic structure and electron dynamics at the GaSb(0 0 1) surface studied by femtosecond pump-and-probe pulsed laser photoemission spectroscopy

Transiently excited electron states at the GaSb(0 0 1) surface have been studied by means of time- and angle-resolved photoemission spectroscopy based on a femtosecond laser system. A normally unpopulated surface electron state has been found at ∼250 meV above the valence band maximum with a strong confinement at the center of the surface Brillouin zone. The lifetime of transiently excited carriers at the intergap surface states has been found to be ∼11 ps, associated with rapid carrier diffusion.     

Reversal of Enantiomeric Retention Order by Using a Single N-Derivatized Dipeptide as Chiral Mobile Phase Additive and Porous Graphitised Carbon as Stationary Phase

In this work the three dipeptides, Z-l-alanyl-l-glutaric acid (Z-l-ala-l-glu), Z-l-phenylanyl-l-glutaric acid (Z-l-phe-l-glu) and Z-glycyl-l-glutaric acid (Z-gly-l-glu) were tested as chiral counter ions for enantiomeric resolution of amino alcohols. The influence of solute and counter ion structure upon retention and enantioselectivity was evaluated. The chiral counter ions were dissolved in a mixture of polar solvents, i.e., ethyl acetate, methanol and acetonitrile and the achiral solid phase used was porous graphitic carbon, marketed as Hypercarb. The enantioselectivities observed for the tested solutes were highly influenced by the used chiral counter ion structure. For example no enantioselectivity was observed for (R,S)-alprenolol using Z-l-ala-l-glu while a separation factor (α) of 1.59 was obtained using Z-l-phe-l-glu as chiral counter ion. High selectivity factors (α > 2.7) were observed between enantiomers of tertiary amines using Z-l-phe-l-glu as counter ion. Interestingly, the structure of the counter ion, as well as the charge on Z-l-phe-l-glu and the mobile phase solvent composition, influenced the retention order of the enantiomers.     

Effect of laser irradiation of C-V characteristics of electrodeposited Ag/Tl-2223/CdSe hetero-nanostructures

One of the innovative technological directions for the high-temperature superconductors has been persued by fabricating the heteroepitaxial multilayer structures such as superconductor-semiconductor heterostructures. In the present investigation, metal/superconductor/semiconductor (Ag/Tl-2223/CdSe) hetero-nanostructures have successfully been fabricated using dc electrodeposition technique and were characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy (SEM) studies. The measurement of junction capacitance as a function of biasing voltage was used for the estimation of junction built-in-potential (V _D) and to study the charge distribution in a heterojunction. The Mott-Schottky plots were measured for each junction in dark and under the photo-irradiation. The effect of laser irradiation on C-V characteristics of hetero-nanostructure has been studied.     

Greedy matching on a grid

A fast solution to the complete minimum matching problem using a greedy heuristic is presented, when the points are distributed on a grid domain. For this a data structure which efficiently supports nearest neighbor searches and deletions from a planar point set is developed.     

A miniature gradient elution system for liquid chromatography with packed capillary columns

A miniaturized continuous gradient elution system was designed for work with packed capillary columns. The retention reproducibility achieved is adequate for many practical applications.     

Comments on a paper concerning the eigenvalues of the rotating harmonic oscillator

It is pointed out that a paper by Flessas on the eigenvalues of the rotating harmonic oscillator recently published in Physics Letters, contains wrong conclusions.     

Intrinsic surface state on Be(0 0 0 1)

Using monochromatized synchrotron radiation in the range 24–30 eV, we have recorded angle-resolved photoemission spectra from a clean Be(0 0 0 1) crystal face. A surface state located in a band gap around Γ with an initial state energy of ?2.8 eV in normal emission was found. For k_∥ along the $\text{Γ}$$\text{M}$ line the surface state disperses upwards and passes E_F at about 55% of the distance to the surface Brillouin zone boundary.