Role of magnetic shear on the electrostatic current driven ion-cyclotron instability in the presence of parallel electric field

Recent observation and theoretical investigations have led to the significance of electrostatic ion cyclotron (EIC) waves in the electrodynamics of acceleration process. The instability is one of the fundamental of a current carrying magnetized plasma. The EIC instability has the lowest threshold current among the current driven instabilities. On the basis of local analysis where inhomogeneities like the magnetic shear and the finite width current channel, have been ignored which is prevalent in the magnetospheric environment. On the basis of non-local analysis interesting modification has been incorporated by the inclusion of magnetic shear. In this paper we provide an analytical approach for the non-local treatment of current driven electrostatic waves in presence of parallel electric field. The growth rate is significantly influenced by the field aligned electron drift. The presence of electric field enhances the growth of EIC waves while magnetic shear stabilizes the system.     

Tunable infrared generation in KTA and applications

Noncollinear difference frequency mixing of dye laser and Nd:YAG second harmonic (fundamental) radiation from a commercial laser system is employed for the generation of 2.7–5.3 μm (1.6–1.7 μm) radiations in a flux-grown KTiOAsO₁ crystal. The generated radiation is used to scan the methane absorption in the fundamental (v ₃) and its first overtone (2v ₃) band at pressure 90 torr in a laboratory made single pass gas cell of length 33 cm.     

关于K个复相关矩阵相等的检验

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Study of theS-matrix near bound states in the continuum

The behaviour ofS-matrix for potentials generating bound states in continuum in the neighbourhood of the positive bound state energies is studied. It is shown that unlike the case of usual negative energy bound states, theS-matrix does not have a pole at the positive bound state energy but becomes unity at the energy corresponding to bound states in continuum. Calculations ofS-waveS-matrix for a local potential constructed by Stillinger and Herrick and a separable nonlocal potential constructed by the present authors verify these results. Our results indicate that the bound states embedded in continuum constructedvia the von Neumann and Wigner procedure cannot be interpreted as resonances with zero width.     

Results from a search for light-mass dark matter with a p-type point contact germanium detector

We report on several features in the energy spectrum from an ultralow-noise germanium detector operated deep underground. By implementing a new technique able to reject surface events, a number of cosmogenic peaks can be observed for the first time. We discuss an irreducible excess of bulklike events below 3 keV in ionization energy. These could be caused by unknown backgrounds, but also dark matter interactions consistent with DAMA/LIBRA. It is not yet possible to determine their origin. Improved constraints are placed on a cosmological origin for the DAMA/LIBRA effect.     

Evaluation of carbonic anhydrase and paraoxonase inhibition activities and molecular docking studies of highly water-soluble sulfonated phthalocyanines

The investigation of carbonic anhydrase and paraoxonase enzyme inhibition properties of water-soluble zinc and gallium phthalocyanine complexes ( 1 and 2 ) are reported for the first time. The binding of p-sulfonylphenoxy moieties to the phthalocyanine structure favors excellent solubilities in water, as well as providing an inhibition effect on carbonic anhydrase (CA) I and II isoenzymes and paraoxonase (PON1) enzyme. According to biological activity results, both complexes inhibited hCA I, hCA II, and PON1. Whereas 1 and 2 showed moderate hCA I and hCA II (off-target cytosolic isoforms) inhibitory activity (Ki values of 26.09 µM and 43.11 µM for hCA I and 30.95 µM and 33.19 µM for hCA II, respectively), they exhibited strong PON1 (associated with high-density lipoprotein [HDL]) inhibitory activity (Ki values of 0.37 µM and 0.27 µM, respectively). The inhibition kinetics were analyzed by Lineweaver–Burk double reciprocal plots. It revealed that 1 and 2 were noncompetitive inhibitors against PON1, hCA I, and hCA II. These complexes can be more advantageous than other synthetic CA and PON inhibitors due to their water solubility. Docking studies were carried out to examine the interactions between hCA I, hCA II, and PON1 inhibitors and metal complexes at a molecular level and to predict binding energies.     

Highly improved electrocatalytic oxidation of dimethylamine borane on silver nanoparticles modified polymer composite electrode

Dimethylamine borane (DMAB) is a promising fuel alternative for fuel cell applications. In this work cyclic voltammetric behavior of DMAB was investigated on the polymerized aminophenol film decorated with Ag nanoparticles in alkaline media. The polymer film was formed on the glassy carbon electrode by electrochemical technique and then, the surface was modified with Ag nanoparticles. The surface of the modified electrode was identified by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy techniques. The developed electrode has displayed high electrocatalytic activity for DMAB oxidation in alkaline media depending on the supporting electrolyte concentration. Experimental parameters such as cycle number used in electropolymerization of p-aminophenol, deposition of Ag nanoparticles and supporting electrolyte were optimized.     

The development of information storage materials — How microscopy can help?

The response of giant magnetoresistance (GMR) devices depends critically on the film microstructure, with parameters such as layer thickness and interfacial abruptness being crucial. This paper presents results obtained using high resolution electron microscopy (HREM), chemical mapping and atom probe microanalysis. Local variations in the magnetic properties are induced by the microstructure and also when the films are patterned to form small elements. These lead to changes in the magnetization reversal mechanism. Some results of the studies of the magnetization reversal carried out using in situ in Lorentz transmission electron microscopy (LTEM) magnetizing experiments are also included.     

Peak effect studies in single crystals CeRu2 and 2H-NbS2

We have studied the peak effect (PE) phenomenon in single crystals of weakly pinned superconductors CeRu₂ and 2H-NbS₂. 2H-NbS₂ is iso-structural and iso-electronic to 2H-NbSe₂, whose similarity with CeRu₂ as regards the PE representing the order-to-disorder transformation of the flux line lattice was claimed some time ago. We report on the step change in equilibrium magnetization across the peak effect in CeRu₂. We also present the vortex phase diagram of 2H-NbS₂ obtained from the magnetization data, and compare the PE phenomenon in 2H-NbS₂ and 2H-NbSe₂.     

PHOTOCHEMICAL GENERATION OF REDUCED QUINONE CATALYSTS OF PHOTOSYSTEM I CYCLIC PHOTOPHOSPHORYLATION ACTIVITY

When reaction mixtures containing 9,10-anthraquinone-2-sulfonate and chloroplasts poisoned with 3–(3,4-dichlorophenyl)-l, l′-dimethylurea were illuminated with white light, photosystem I-catalyzed cyclic photophosphorylation was observed. Illumination of identical reaction mixtures with red light produced no ATP synthesis. This phenomenon is due to photoreduction of the anthraquinone which is supported by the electron donor activity of Tricine buffer. The photoreduction reaction was used to generate reduced catalysts (anthraquinone sulfonate, menadione bisulfite) of photosystem I cyclic photophosphorylation activity. The rates of ATP synthesis obtained by this method (250–300 μmol/h-mg chlorophyll) indicate that sulfonated quinones are efficient mediators of cyclic electron transport around photosystem I. Although the activity catalyzed by these compounds is highly sensitive to dibromothymoquinone, very little decrease in activity is observed with antimycin A.