BaO−B2O3 system and its mysterious member Ba3B2O6

The first systematic study of the BaO–B₂O₃ system and barium orthoborate Ba₃B₂O₆ (3BaO·B₂O₃) was reported in 1949. Thereafter, the system was repeatedly refined but the structure of Ba₃B₂O₆ compound has not been adequately studied yet. In our study we have, for the first time, obtained the crystalline samples of Ba₃B₂O₆. The solved structure (Pbam, a = 13.5923(4) Å, b = 13.6702(4) Å, c = 14.8894(3) Å) belongs to the class of ‘anti‐zeolite’ borates with a pseudotetragonal [Ba₁₂(BO₃)₆]⁶⁺ cation pattern which contains channels along the c axis filled with anionic clusters. The Ba₃B₂O₆ compound may be regarded as a fluorine‐free end‐member of the Ba₃(BO₃)_2–xF_3x solid solution. The BaO–B₂O₃ phase diagram presented in our study is based on our research and literature data.     

Method of Power Adaptation for Signals Emitted in a Wireless Network in Terms of Neuro-Fuzzy System

Wireless Personal Communications - Attenuation of the signal propagating between the emitting and receiving antennas in a wireless network requires adaptation of the power of the emitted signal for...     

Effect of Gamma Irradiation on Dynamics of Charge Exchange Processes between Single Trap and Nanowire Channel

In the present study, transport properties and single trap phenomena in silicon nanowire (NW) field‐effect transistors (FETs) are reported. The dynamic behavior of drain current in NW FETs studied before and after gamma radiation treatment deviates from the predictions of the Shockley–Read–Hall model and is explained by the concept taking into account an additional energy barrier in the accumulation regime. It is revealed that dynamics of charge exchange processes between single trap and nanowire channel strongly depend on gamma radiation treatment. The results represent potential for utilizing single trap phenomena in a number of advanced devices.     

Studying the Characteristics and Optimizing the Parameters of a Parallel-Plate Chamber Used As a Detector for Time-of-Flight Measurements

The evolution of a technique for precise and highly efficient time-of-flight measurements of minimum-ionizing particles is described. The technique is based on the use of parallel-plate chambers operating in the avalanche mode of gas amplification. The search for the proper material and design for the detector, the choice of the gas mixture composition, the results from the investigation of the gas discharge in the chamber, and the probability of a spark discharge are discussed, along with the development of fast and low-noise electronics.By optimizing the parameters of a parallel-plate chamber, a simple, reliable, and low-cost time-of-flight detector with a resolution of 200 ps and an efficiency of 90% or higher for minimum-ionizing particles was developed.     

An Online Contactless Investigation of the Meniscus Velocity in a Continuous Casting Mold Using Lorentz Force Velocimetry

Metallurgical and Materials Transactions B - Monitoring the meniscus velocities of molten steel in continuous casting molds is critical for revealing the velocity field in the whole mold and...     

Ab Initio Calculations and Measurements of Thermoelectric Properties of V2O5 Films

Density functional theory and the Boltzmann transport equation were used to calculate the thermoelectric transport coefficients for bulk V₂O₅ and MV₂O₅ (M = Cr, Ti, Na, Li). The structural relaxation for the given compounds based on the ABINIT code was observed. The temperature dependences of the Seebeck coefficients as well as electrical and thermal electrical conductivities of all relaxed structures displayed anisotropic behavior. Electrooptical measurements of thermoelectric properties were carried out on V₂O₅ thin films obtained by thermal evaporation with different post-annealing treatments. A Seebeck coefficient of ?148 μV/K at T = 300 K was obtained in the in-plane direction for V₂O₅ thin films with thickness less than 100 nm.     

Homogeneous vs. catalytic combustion of lean methane—air mixtures in reverse-flow reactors

To carry out a comparative assessment of a recently proposed idea of using thermal flow-reversal reactors (TFRR) for mine ventilation air, the results for the catalytic flow-reversal reactor (CFRR) investigated within the European Project (2003) are briefly presented. Next, experimental investigations of thermal combustion are presented in this paper. These consisted of the kinetic study of homogeneous combustion in the pelletized bed and in the monolith. Kinetic equations for the two cases are derived and discussed. Experimental autothermal reverse-flow operation in a laboratory setup was performed. Due to the high heat capacity of the wall and insulation of the pelletized bed reactor, with considerable heat losses to the surroundings, autothermal operation was successful only in the monolithic reactor. It is finally concluded that the thermal combustion can be competitive compared with the catalytic oxidation.     

Estimating IC susceptibility to single-event latchup

The results are presented of a computer and physical simulation concerned with the estimation of CMOS-circuit susceptibility to single-event latchup. A laser-simulation procedure is proposed and tested in which only the most sensitive areas are irradiated. The estimates are found to agree with the measurements.     

Electronic properties of AlVO<Subscript>4</Subscript> for gas sensor applications

The binary oxide AlVO₄ is being proposed as a new gas sensor material. An X-ray investigation, IR spectrum analysis, resistivity and a calculation of the electronic structure of this compound have been carried out in order to determine its structural, absorptive and sensor properties. The fragment [Al₃V₃O₂₃]¹⁸⁻ is the chain chosen to study the electronic properties of AlVO₄ in the framework of the frontier orbital theory and the interaction between molecules has been described by the Molecular Electrostatic Potential (MEP). The vibration analysis and the simulated infrared spectrum (IR) were calculated for the unit [Al₃V₃O₂₃]¹⁸⁻ and a comparative analysis with the experimental spectrum of AlVO₄ is also presented.