Chemiluminescent GeCl4 + O2 + Ar/He/Reactions

A chemiluminescent flame was produced in the reaction between GeCl₄ and an excited mixture of argon or helium with oxygen. Spectra of the reaction products were recorded and studied. Relative populations of the products in analyzed electronic, vibrational and rotational states corresponded to different temperatures.     

Role of phonon dynamics in the thermopower of niobium hydrides

The thermopower of NbH_x alloys for x varying from 0.607 to 0.883 has been examined at temperatures ranging from 100 to 430 K. It was found that the transition from orthorhombic β to cubic α' phase is accompanied by a strong change of thermopower. It is concluded that differences in phonon spectra of these two phases are responsible for the observed differences in the transport properties. The sensitivity of the thermopower to any other phase transitions in this system has been observed as well.     

On-shell baryon-baryon semi-local duality relations

Zeitschrift für Physik C Particles and Fields - Parent-parent on-shell semi-local duality relations betweens − andu-channel resonances in πN amplitudes are studied. The duality...     

Determination of antibiotic residues in honey

Honey produced by honeybees is a valuable food product. The presence of xenobiotics in honey may harm its quality and constitute a danger to human health. Antibiotics are commonly applied by beekeepers to eliminate disease among honeybees. Moreover, ubiquitous administration of antibiotics may cause bacteria to become resistant to many drugs and spread antibiotic-resistant strains of bacteria. Appropriate sample preparation and determination of antibiotics at very low concentrations in foodstuffs are real analytical challenges. This article reviews analytical methods used for determination of residues of different sorts of antibiotic in honey and other honeybee products.     

Estimation of platinum in environmental water samples with solid phase extraction technique using inductively coupled plasma mass spectrometry

A solid phase extraction technique for the determination of platinum(IV) at trace levels by inductively coupled plasma mass spectromA solid phase extraction technique for the determination of platinum(IV) at trace levels by inductively coupled plasma mass spectrometry (ICP-MS) was developed. The method was based on retention of platinum in a sample on silica gel modified with aminepropyl groups. The retention of platinum(IV) from the sample solution and the recovery of platinum with 1.0 mol L⁻¹ thiourea solution were quantitative. The relative standard deviation (RSD) was calculated as 5% (n = 7) at the 10 ng L⁻¹ level. The enrichment factor was found to be (50-fold) for 250 mL of water sample. Under optimum conditions, the method detection limit (MDL) was found to be 1 ng L⁻¹ for platinum in water matrices. Recoveries of Pt from spike addition to atmospheric water samples were quantitative (80–95%). The present method was used for the determination of platinum in precipitation, throughfall and runoff water samples.      

Crystallization effects in amorphous Cd3As2 films

The amorphous to crystalline transformation due to electron beam or heat treatments was studied. From the results it was concluded that the temperature of the transformation is higher than 300°C - higher than the epitaxy temperature for the deposition process. The a→c transition proceeds in several stages. By using the “cross-cut” method the activation energy for crystallization was estimated to be 2 eV.     

Scaling laws of complex band random matrices

We study a model of complex band random matrices capable of describing the transitions between three different ensembles of Hermitian matrices: Gaussian orthogonal, Gaussian unitary and Poissonian. Analyzing numerical data we observe new scaling relations based on the generalized localization length of eigenvectors. We show that during transitions between canonical ensembles of random matrices the changes of statistical properties of eigenvalues and eigenvectors are correlated.     

The spectrum of theP-wave baryons and hadronic loops

In current QCD inspired analyses of the hadron spectrum nonperturbative quark loops are generally neglected. We study the validity of this assumption by estimating mass splittings and mixings induced by hadronic mass renormalization to the (70,1^?) baryon multiplet. All intermediate states in the loop composed of a ground state meson (0^?+, 1^??) and a ground state baryon (1/2⁺, 3/2⁺) are included. We use a³ P ₀ type model for the partial decay widths and spectral functions. Using unitarity and analyticity one finds a definite prediction for the masses and mixings, in good agreement with experiment, even when the perturbative one-gluon exchange is completely ignored. Our result thus allows for a smaller one-gluon exchange overall contribution, which would resolve the difficulty of the apparent smallness of the observed spin-orbit coupling. In particular if one adds the (nonperturbative) unitarity corrections to the one-gluon exchange contribution the gluon coupling constant can be reduced by a factor of 3 giving a reasonable value α_s≈0.3.