Influence of the dentate fascia on the sensory responses of neurons in hippocampal field CA3

In experiments with unanaesthetized rabbits the influences of electric stimulation of the dentate fascia (DF) on the extracellularly recorded spontaneous and evoked activity of the CA3 neurones were investigated. Stimulation of a fixed locus in the DF during recording in the CA3 by a microelectrode, shifted along the longitudinal axis of the hippocampus, supported the notion of the topical, "segmental" organization of connections between the DF and CA3. A relatively narrow "active zone" (approximately 700 nm) appeared in the CA3 during the threshold DF stimulation: it was bordered by zones with predominantly inhibitory responses to stimulation. The CA3 neurones in the "active zone" rapidly lost their reactivity to sensory stimuli. In the "inhibitory" and "zero" zones the normal level of reactivity to sensory stimuli was preserved.     

Defect Structure of Alkaline-Earth,Cadmium, and Lead Titanates

X-ray powder diffraction, scanning electron microscopy, and x-ray microanalysis data indicate that Ba, Ca, Sr, Cd, and Pb titanates contain defect structures associated with crystallographic shear. Spatially periodic shear gives rise to modulated displacements of the Ti and O atoms across the shear plane, resulting in long-period structures. The parameters of such structures depend on the nature of the sample (single crystal, ceramic, or powder), its microstructure, and the crystal chemistry of the titanate.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 5, 2005, pp. 573–584.Original Russian Text Copyright © 2005 by Reznichenko, Shilkina, S. Titov, Razumovskaya, V. Titov, Shevtsov.     

Special Important Aspects of the Thomson Effect

A comprehensive study of the mechanisms of heating and cooling originating from an electrical current in semiconductor devices is reported. The variation in temperature associated with the Peltier effect is not related to the presence of heat sources and sinks if the heat flux is correctly determined. The Thomson effect is commonly regarded as a heat source/sink proportional to the Thomson coefficient, which is added to the Joule heating. In the present work, we will show that this formulation of the Thomson effect is not sufficiently clear. When the heat flux is correctly defined, the Thomson heat source/sink is proportional to the Seebeck coefficient. In the conditions in which the Peltier effect takes place, the temperature gradient is created, and, consequently, the Thomson effect will occur naturally.     

Polyaniline–13X zeolite composite‐supported platinum electrocatalysts for direct methanol fuel cell applications

We successfully synthesized 13X zeolite using a hydrothermal method. Then, composites of polyaniline (PANI) with 13X zeolite and PANI–13X with platinum were prepared by chemical oxidative polymerization and chemical reduction, respectively. Field emission scanning electron microscopy, X‐ray diffraction, Raman spectroscopy and Brunauer–Emmett–Teller techniques were used to characterize the PANI–Pt and PANI–Pt–13X composites. Further, the electrocatalytic activity towards methanol oxidation of the synthesized catalysts was explored using cyclic voltammetry in 1 mol L^?1 CH₃OH + 0.5 mol L^?1 H₂SO₄ solution. From the obtained results, PANI–Pt–13X shows superior performance compared to PANI–Pt towards methanol oxidation and electrical conductivity. Hence, the 13X zeolite‐incorporated PANI–Pt composite could be an efficient catalyst for direct methanol fuel cell applications. © 2019 Society of Chemical Industry     

Hot-pressed ceramic SiC–YAG materials

Dense SiC-based ceramic materials containing yttrium aluminum garnet (YAG) as an oxide sintering aid have been prepared by hot pressing in the temperature range 1750–1850°C. As a result of melting, the oxides fill spaces between the SiC particles, contributing to the densification of the material and mass transport during the hot pressing process. The present results demonstrate that relatively small amounts of the oxides (≤5 wt %) are needed to ensure a high degree of densification of the SiC–YAG materials. The best physicomechanical properties are offered by the SiC + 3 wt % YAG material sintered at a temperature of 1850°C: ρ = 3.24 ± 0.01 g/cm³, П = 1.1 ± 0.1%, σ_b = 640 ± 10 MPa; K_Ic = 6.4 ± 0.2 MPa m^1/2, Еel = 410 ± 20 GPa, and HV = 26.0 ± 0.2 GPa. This material experiences predominantly intercrystalline fracture.     

Interaction of Acoustic Waves with Moving Boundaries

Russian Engineering Research - The interaction of an ultrasonic probe with a vibrating boundary surface is considered in a quasi-static approximation. A model of boundary-problem type is expressed...     

Freestanding fiber mats of zeolitic imidazolate framework 7 via one‐step,scalable electrospinning

We demonstrated the fabrication of freestanding zeolitic imidazolate framework 7 (ZIF‐7) nanofiber (NF) mats by means of one‐step, scalable electrospinning. The formation of ZIF‐7 nanoparticles embedded in polymer fibers was unambiguously pinpointed via X‐ray diffraction, transmission electron microscopy, and adsorption studies. The NF mats exhibited excellent characteristics, with an average diameter of 245 nm, in the adsorption and desorption of carbon dioxide (CO₂); this makes them attractive candidates for gas separation and other selective filtration applications. This excellent property of the ZIF‐7 mats was explained by the gate‐opening phenomenon of ZIF‐7, which yielded a stepwise increase in the overall CO₂ uptake capacity. The mechanical strength of the NF mats was also obtained via large‐strain uniaxial tensile deformation, which enabled preliminary assessment of the mat's suitability for textiles and membranes in targeting separation and filtration applications with large‐area permeability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43788.     

Development of Coatings for Protection of Blast Furnace Air Tuyeres

Metallurgist - A coating based on boron carbide, aluminum oxide slip, and also aluminosilicate adhesive is used to improve the service properties of Cu–Al diffusion layer on blast furnace air...