Order structure of methanol along the 200-bar isobar in the temperature range of 60–320°C according to IR spectroscopy

The topology and energetic characteristics of hydrogen bonded clusters in methanol and methanol-heptane mixtures are investigated by IR spectroscopy over a wide temperature range. The average number of hydrogen bonds per methanol molecule was calculated. Based on an analysis of changes in the spectral parameters of O...H intramolecular bonds, conclusions on structural rearrangements in the mixture under study at elevated temperatures are drawn.     

Antiferromagnetic fluctuations in heavy fermion CePdSn according to Mössbauer spectroscopy data

The transition from single-ion Kondo-behavior to the magnetically ordered state in the heavy fermion intermetallic compound CePdSn is studied using ¹¹⁹Sn Mössbauer spectroscopy. It is found that the temperature evolution of the experimental spectra can be described well by a two-level relaxation model of the same particles. This allows one to treat the spin-slip model of the magnetic structure of CePdSn as the decomposition of the total volume of the sample into antiferromagnetic domains.     

Variation in the energy spectra of primary cosmic rays for 2007–2015, according to data from the URAGAN muon hodoscope

Simulations of how secondary components of cosmic rays are generated and pass through the atmosphere are performed using the CORSIKA software package. The relationship between the vertical projection of the local anisotropy vector A _Z and the index of primary particle spectrum γ is calculated. The time series of A _Z for 2007–2015 are obtained using data from the URAGAN muon hodoscope. Matrix data corrected for barometric and temperature effects are used to estimate A _Z . Using the A _Z time series, the average annual daily variations Δγ are estimated. Annual and daily variations in the slope of the energy spectrum of primary protons are observed.     

Synaptic inhibition and γ-aminobutyric acid in the mammalian central nervous system

Signal transmission through synapses connecting two neurons is mediated by release of neurotransmitter from the presynaptic axon terminals and activation of its receptor at the postsynaptic neurons. γ-Aminobutyric acid (GABA), non-protein amino acid formed by decarboxylation of glutamic acid, is a principal neurotransmitter at inhibitory synapses of vertebrate and invertebrate nervous system. On one hand glutamic acid serves as a principal excitatory neurotransmitter. This article reviews GABA researches on; (1) synaptic inhibition by membrane hyperpolarization, (2) exclusive localization in inhibitory neurons, (3) release from inhibitory neurons, (4) excitatory action at developmental stage, (5) phenotype of GABA-deficient mouse produced by gene-targeting, (6) developmental adjustment of neural network and (7) neurological/psychiatric disorder. In the end, GABA functions in simple nervous system and plants, and non-amino acid neurotransmitters were supplemented.     

Low-frequency lattice dynamics in Ba1−x KxBiO3 oxides according to 39K NMR data

The spin-lattice relaxation times T ₁ in Ba_1−x K_xBiO₃ (x=0.3, 0.4, 0.5) were measured in the normal temperature range (20–300 K).A substantial contribution to the spin-lattice relaxation rate from dynamic local distortions of the crystal lattice near potassium atoms is found. The activation energy of this process increases with decreasing potassium concentration, and the frequency of lattice excitations decreases. The nature of the low-frequency lattice dynamics is discussed. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 5, 344–349 (10 September 1999)     

Effect of sintering temperature on the chemical state of ions in the Ba1 − x Sr x TiO3 (x = 0.2) system,according to X-ray photoelectron spectroscopy data

The chemical state of ions in different samples of ceramics of the Ba_{1 ? x} Sr _x TiO₃ (x = 0.2) system produced by varying only a single technological parameter (sintering temperature T _S) is studied by means of X-ray photoelectron spectroscopy. The X-ray electron spectra of the Ba4d, Sr3d, O1s, and Ti2p levels reveal well-marked fine structures. As expected, the energy position and intensity of the features of this fine structure vary with T _S.     

New approach to enhance the up—conversion efficiency in the Ho^3＋—Yb^3＋ co—doped system

We investigate the up-conversion luminescence spectra of Ho³⁺-Yb³⁺ co-doped materials excited with two types of laser. It is found that the efficiency of green emission (⁵S₂－⁵I₈) can be enhanced by restraining the transition of ⁵S₂－⁵I₇ since the two types of radiation both start on the ⁵S₂ level. We propose an important approach to enhance an expected up-conversion emission.     

Optical conductivity spectral anomalies in the off-center rattling system β-Ba8Ga16Sn30

We present optical conductivity studies of the type-I clathrate Ba8Ga16Sn30, using a terahertz time-domain spectrometer (0.3-3.0?THz). The lowest-lying spectral peak at 0.72?THz due to the Ba(2) ion's off-center vibration in the oversized cage shows a drastic and anomalous temperature dependence. Below about 100?K, the single broad peak splits into two subpeaks, and with further lowering of the temperature, the spectral shape of this so-called rattling phonon shows non-Boltzmann broadening to the point that the linewidth becomes comparable to the peak frequency. Whereas the initial splitting can be understood by assuming a multiwell anharmonic potential, the strong linewidth broadening toward low temperature cannot, since the Boltzmann factor generally sharpens the low-temperature spectra. The observed behavior suggests strong interaction between the local anharmonic phonons and other excitations.     

Variable composition of cosmic rays with E 0 ≥ 1017 eV according to the data from the muon detectors of the Yakutsk EAS array

The lateral distribution of muons with the threshold E _μ ≈ 1.0 secθ GeV (where θ is the zenith angle) in extensive air showers (EASs) with the energy E ₀ ≈ 10^17–19 eV in various observation periods from November 1987 to June 2013 has been analyzed. The experimental data have been compared to the calculations within various models of the development of EASs from the CORSIKA package. The experimental data are in the best agreement with the QGSJET II-04 model. The mass composition of cosmic rays with E ₀ < 2 × 10¹⁸ eV before 1996 was much lighter than that in a later time interval.     

Cooperative dynamics of coupled motor–cargoes system with stochastic interactions in the crowded environment

In this study, we investigate the cooperative transport behaviors of coupled motor–cargoes system, in which multiple passive cargoes stochastically interact with one active Brownian motor. The environment with stochastic interactions is characterized by the concentration (reflecting the cargo’s number in unit volume) and switching rate (reflecting the interacting stability between motor and cargoes), based on which the stationary multiple-state process can be employed to describe the fluctuating-cargo state in the coupled system. By analyzing the average probability current of decoupled system in the thermodynamic limit, we effectively study the possibility of cooperative transport through stochastic cargoes to behave rich dynamical behaviors, including the directed current, current reversal, stochastic resonance (SR) and stochastic inhibition (SI), inverse SR and SI, even without the effect of external driving force. Based on numerical results, we systematically discuss the transport dependence on various parameters, including the cargo concentration in the crowded environment, cargo capacity of the motor, driving amplitude of external periodic force, and medium temperature. Obviously, the sensitivity of transport process to parameter changes can be used by the environment to regulate its cargo traffic, which also provides latent support for manipulating the transport performance and optimizing the coupled structure in artificial nano-machines.     

Applications of the Judd—Ofelt theory in lanthanide—chelidamic acid complexation

The coordination chemistry of trivalent lanthanides with chelidamic acid was studied using fluorescence and absorption spectroscopic methods. The speciation was determined using Eu(III) fluorescence techniques. The stability constants and the oscillator strengths were determined for the Ho(III) complexes from absorbance measurements of a Ho(III) hypersensitive transition. The lanthanide coordination chemistry of chelidamic acid and dipicolinic acid is compared.     

Low-temperature phase behaviour of the binary system water–oxyethylated glycerol of polymerization degree n = 5 and intermolecular interactions in the system

In this paper, phase and glass transitions occurring in a binary system water–oxyethylated glycerol of polymerization degree n = 5 (OEG _{n =5}) are studied by differential scanning calorimetry (DSC) in the concentration range 0–100% (w/w) at temperatures lower than 273 K. The supplemented phase diagram of this system has been constructed for the first time. Concentration and temperature regions for the existence of a completely amorphous state and a heterogeneous crystalline/amorphous state have been determined. Processes of formation of crystalline and amorphous phases in the water–OEG _{n =5} system are studied by optical cryomicroscopy, both during cooling and subsequent heating. The cryomicroscopic data confirm the conclusions derived from the DSC data analysis. The number of strongly and weakly bound water molecules per OEG _{n =5} molecule has been calculated on the basis of the analysis of the supplemented phase diagram of the water–OEG _{n =5} system. The hydration number of an OEG _{n =5} molecule has been also determined by infrared spectroscopy.     

Highly transparent ceramics for the spectral range from 1.0 to 60.0μm based on solid solutions of the system AgBr-AgI-TlI-TlBr

The article is devoted to the technology for obtaining optical ceramics of Ag Br-Tl I and Ag Br-Tl Br_0.46I_0.54 systems and manufacturing samples with different compositions.The new heterophase crystal ceramics are transparent without absorption windows in the spectral range from 1.0 to 60.0μm.In the ceramics’transparency spectra based on the Ag Br-Tl I and Ag Br-Tl Br_0.46I_0.54 systems fusibility diagrams,with an increase in the thallium halides mass fraction,as well as the replacement of the bromine ion with iodine,the maximum transparency shifts to a long infrared region.     

Scaling of the shear viscosity of the system nitrobenzene —n-heptane in the critical region

The temperature dependence of shear viscosity of the system nitrobenzene-n-heptane has been studied near the critical concentration. The critical exponent of the shear viscosity Φ was calculated from the empirical formula and compared with the theoretical and experimental results obtained for other critical systems. The shear viscosity satisfies scaling law relations similar to those previously established for equilibrium properties.     

Scaling of the shear viscosity of the system nitrobenzene—n-hexane in the critical region

The shear viscosity of the system nitrobenzene—n-hexane was measured along the isochores near the critical concentration. By applying the empirical formula η = η_idε^-Φ _sp, the critical exponent of the shear viscosity Φ was determined.     

Torsion—rotation interactions in monodeuterated acetaldehyde

This paper presents an analysis of previously observed rotational transitions up to J = 17 of the sym and asym rotamers of monodeuterated acetaldehyde using a three-level Hamiltonian incorporating connections between rotational states of the v_sym = 0, v_asym = 0⁺ and v_asym = 0 ^? torsional energy level manifolds. Rotational transitions observed to be significantly perturbed in earlier studies, where the spectrum was fitted using a single-level Hamiltonian for the v_sym = 0 torsional state and a separate two-level Hamiltonian for the non-rigid asym states, are now fitted satisfactorily. It is confirmed that the perturbations detected in the earlier studies and tentatively attributed there to torsion-rotation interactions between the energetically distinct sym and asym manifolds do indeed arise as a consequence of such interactions. Rotational and quartic centrifugal distortion constants are given for each torsional state, together with torsion-rotation coupling constants primarily responsible for the perturbations noted in the earlier studies. Tunnelling between the energetically distinct sym and asym potential wells of the torsional potential energy function is also discussed.     

Evolution of dust shells in Tolman–Bondi space–time according to the Weierstrass approach

The Einstein evolution of a dust shell universe with spatial spherical symmetry is analyzed. The implicit and parametric solutions of Tolman–Bondi equations are proposed in order to show its agreement with the rectilinear solutions of Kepler’s problem. Finally, a complete systematization of Tolman–Bondi models is obtained through the classical Weierstrass approach.