Thermal modulation in Zeno and anti-Zeno effects on quantum measurement

We have proposed the mathematical formulations of quantum Zeno and anti-Zeno effects at non-zero temperature on vibrational population transfer and dissociation of a diatomic system. The proposed formulation has been tested for diatomic systems HBr⁺ and HI using time-dependent Fourier grid Hamiltonian method. The effect of temperature on the dynamics is incorporated through the population distribution at different vibrational states following Boltzmann distribution formula. It has been found that with increase in temperature Zeno effect increases and anti-Zeno effect decreases in case of survival probability on ground vibrational state. In case of dissociation, with increase in temperature Zeno effect increases while anti-Zeno effect remains almost same.     

Synthesis and characterization of N,N-dimethyldodecylamine-capped Aucore-Pdshell nanoparticles in toluene

In this paper a convenient route for synthesizing Au(core)-Pd(shell) bimetallic nanoparticles in toluene has been reported as a result of co-reduction of gold(III) and palladium(II) precursors in toluene. N,N-Dimethyldodecylamine was used as a capping agent for the core-shell particles, which not only imparts stability to the organosol but also controls morphology of the evolved particles. The particles were characterized using UV-visible, transmission electron microscopy, and X-ray diffraction measurements. All results substantiate the formation of core-shell structure of the synthesized particles.     

Inflationary Brans-Dicke universe andG

In a recent paper, Mathiazhagan and Johri reduced the field equations for an isotropic, homogeneous, and almost flat universe with a constant vacuum-energy density by Brans-Dicke theory to a pair of coupled differential equations. They also obtained a particular solution of these equations. Further, they used this particular solution of the equations to estimate the value of the gravitational constant. Here we obtain the complete set of solutions of the above-mentioned coupled differential equations and improved the estimate of Mathiazhagan and Johri of the gravitational constant.     

Hypersonic flow past a sphere

The effects of dissociation or ionization of air on the analytical solution for hypersonic flow past a sphere are considered here, under certain assumptions. It has been assumed that the shock wave is in the shape of a sphere, that the density ratio across the shock is constant, that the flow behind the shock is at constant density and that dissociation or ionization only occurs behind the shock wave. Thus the effects of the compressibility of the air, variation of density ratio along the shock, and the department of the shock shape from being circular are not taken into account. Here the velocity, pressure, temperature, pressure coefficient and vorticity, etc., at any point between the shock and the surface of the sphere in the presence of dissociation or ionization are obtained. In addition, shock detachment distance, drag coefficient, stagnation point velocity gradient and sonic points on the shock and the surface have also been obtained. The results have been compared with the corresponding results obtained in the case when dissociation or ionization does not occur behind the shock.     

Thermopower anisotropy in magnetic films of Co and Ni plated in presence of an external magnetic induction

Electroplated films of cobalt and nickel were grown on copper substrate both in absence and presence of external magnetic induction ranging from 25 to 72 gauss. The latter films showed a magnetic behaviour and an anisotropy in thermopower with respect to the direction of magnetisation.     

The specificity of the colour reaction between ammonia and 3-phenyl-2-thiohydantoin

The colour reaction between 3-phenyl-2-thiohydantoin and ammonia is studied quantitatively. Determinations of 0.1–0.6 μmoles of 3-phenyl-2-thiohydantoin are possible with a precision close to 2%. In analyses of amino acid mixtures for glycine after conversion to 3-phenyl-2-thiohydantoin, only derivatives of serine and threonine interfere to a slight extent. The specificity of the primary colour reaction with ammonia, and the structural requirements for it are discussed; a structure for the pigment species is proposed.     

Photothermally induced Bergman cyclization of metalloenediynes via near-infrared ligand-to-metal charge-transfer excitation

Reaction of 1,2-bis(tert-butyldimethylsilyloxy)-4,5-diiodobenzene with 2 equiv of phenylacetylene followed by deprotection with KF/HBr yields the catechol-enediyne ligand 4,5-bis(phenylethynyl)benzene-1,2-diol (CatED, 1). Metathesis of VO(SALIMH)ACAC.CH(3)OH (2) with 1 and subsequent air oxidation yields (4,5-bis(phenylethynyl)-1,2-dihydroxyphenyl)[4-(2-(salicylideneamino)ethyl)imidazolyl]oxovanadium(V).CH(3)OH [VO(SALIMH)CatED], (3), in 85%. The thermal Bergman cyclization temperature for 3 is very high (246 degrees C), which is expected for a rigid, benzannulated enediyne motif. The electronic spectrum of 3 exhibits two strong ligand-to-metal charge transfer (LMCT) transitions centered at 584 nm (epsilon = 6063 M(-)(1) cm(-)(1)) and 1028 nm (epsilon = 8098 M(-)(1) cm(-)(1)). These transitions derive from CatED-to-V(V) ligand-to-metal charge transfer, the assignment of which is verified by resonance enhancement of several CatED vibrational modes in the Raman spectra obtained with lambda = 785 vs lambda = 457.9 nm under low power and/or temperature conditions. At elevated temperatures (113-323 K) and powers (2-5 mW), excitation of 3 in the solid state with lambda = 785 nm leads to generation of a black, sparingly soluble, fluorescent product that exhibits weak vibrational features in the 580-600, 1200-1350, and 1450-1600 cm(-)(1) regions, indicative of V-O (CatED) and aromatic ring units. The C=C ring modes correspond well with the vibrational characteristics of poly(p-phenylene) and derivatives thereof. Additionally, materials generated in both the solid-state thermal and photothermal reactions of 3 demonstrate the formation of high molecular weight species ranging from 5000 to 274 000. On the basis of these data and the literature precedent for formation of poly(p-phenylene) via thermolysis of simple enediynes, the reaction poses a unique approach for photoinitiating Bergman cyclization with long-wavelength excitation, as well as the generation of polymeric products.     

Microwave absorption and paracoherence excess conductivity studies in high-Tc superconductors

Single phase polycrystalline samples of La_1.8Sr_0.2CuO₄, YBa₂Cu₃O_7−δ and Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O_y high-T_c superconductors have been studied using XRD, SEM, EDAX, (T), χ_AC and EPR techniques. Detailed investigations on low-field-dependent microwave absorption have been carried out in order to investigate the effects of field exposure, field cooling, zero field cooling and amplitude of field variation on the samples. The results have been discussed on the basis of granular model via Josephson junctions of high-T_c superconductors. Over and above, paracoherence excess conductivity analysis has been carried out in all the three samples. The critical exponent (γ) estimated for all the three samples in close vicinity to their respective transition temperatures has an excellent agreement with the theoretically predicted value for 3-dimensional XY-ferromagnet (γ = 1.33 for D = 3, N = 2).