79 research outputs found

    Stop Bleeding Mobile Device "Plasmamed" Based on Low-temperature Gas Plasma

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    Creation of a mobile device to stop bleeding, sterilize biological tissues and other surfaces (bandages), disinfect food, beverages, air, and stimulate rapid healing of wound surfaces is observed in this article. Plasmomed is based on the current (available) technologies of medical application of low-temperature atmospheric pressure plasma. The multi-digit combined plasma gun is created as part of the developed mobile device which is designed to achieve a coagulation effect, to stimulate accelerated healing of wound surfaces based on the use of low-temperature gas plasma of atmospheric pressure, which allows for effective hemostasis of wound surfaces with simultaneous sterilization of surrounding tissues and dressing materials. In addition, due to the using several types of high-frequency electromagnetic plasma production in one device, it was possible to significantly simplify the final product, to automate its operation modes, which provides mass-dimensional characteristics for its mobile use. Keywords: plasma, medical device, stopping bleeding, low-temperature atmospheric pressure plasma

    Investigation of magnetic flux gradients in hard superconductors

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    Analytical calculations of the transverse magnetostriction in a thin hard superconductor are presented in relation to the distributions of currents and fields within a superconducting specimen in a varied magnetic field. The approach is successfully tested on high-temperature superconductors. The flux distribution derived from magnetostriction measurements is in satisfactory agreement with that obtained from computer processing of magnetooptical images. The magnetic flux distribution below the irreversibility line of hard superconductors is derived from both original magnetization and magnetostriction measurements and image processing. Perfect consistency of the results is obtained for a family of high-temperature superconductors (La₂₋xSrxCuO₄, Bi₂Sr₂CaCu₂Ox, YBa₂Cu₃O₇₋d)

    Electronic structure and magnetostrictive sensitivity of Fe-B metallic glasses

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    The effect of mechanical tensile stresses 0 ≤ σ ≤ 62 MPa on the low-field (0 ≤ H ≤ 45 Oe) magnetization curves of the metallic glasses Fe₁₀₀₋xBx (x=14, 16, 17, 20) is studied at temperatures of 77 and 300 K. The correlation between the electronic structure of the glasses and their magnetostrictive sensitivity ks is revealed: the eutectic metallic glass Fe₈₃B₁₇, which possesses a special electronic structure with a 30% lower conduction (sp) electron density, has a value of ks differing substantially from that of the other metallic glasses studied. Under low stresses (0 ≤ σ ≤ 22 MPa) the eutectic alloy possesses a magnetostrictive sensitivity ks(σ₁) which is higher than that of the rest of the alloys studied, while under high stresses (22 MPa ≤ σ ≤ 62 MPa) its magnetostrictive sensitivity ks(σ₂) is close to zero

    Irreversible magnetostriction and magnetization of the superconduting 2H-NbSe₂ single crystals in a peak-effect regime

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    Magnetostriction mea sure ments in the mixed state of superconducting 2H-NbSe₂ single crystals under in-plane magnetic fields 0-12 T have revealed a peak on the magnetostriction versus magnetic field dependences in the vicinity of the upper critical field Hc₂. The peak value of the longitudinal magnetostriction is higher by more than an order of magnitude in comparison with that of the trans verse magnetostriction when measured along the hexagonal axis. Analysis of the measured field dependences of the magnetostriction and magnetization of 2H-NbSe₂ allows one to relate the observed peculiarities of magnetostriction with the loss of order in the lat tice of Abrikosov vortices, which occurs by a first-order phase transition. Remove selecte

    Magnetostriction in the mixed state of superconducting 2H-NbSe₂ single crystals

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    Magnetostriction measurements on 2H-NbSe₂ single crystals in the temperature range 1.5-8 K in a magnetic field up to 14 T are reported. Peak and oscillations in the measured field dependences of magnetostriction were observed near Hc₂. The reversible and irreversible components are separated and analyzed in the region of peak. The scaling parameters are defined, the contribution of the elastic constants dependence on magnetic field is demonstrated. The oscillatory component is discussed regarding Landau quantization of electronic spectrum

    Antiferromagnet–ferromagnet phase transition in lightly doped manganites

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    Magnetic and structural phase diagrams of the La₀.₈₈MnOx, La₁₋xSrx(Mn₁₋x/₂Nbx/₂)O₃, Nd₁₋xCaxMnO₃, and Bi₁₋xCaxMnO₃ series constructed on the basis of x-ray, neutron powder diffraction, Young’s modulus, magnetization and resistivity measurements are presented. It is shown that the main factor controlling the antiferromagnet–ferromagnet phase transition in the manganites is a type of an orbital state. The results are discussed in the framework of structurally driven magnetic phase separation model

    Photoluminescence of ortho-bromobenzophenone

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    Phosphorescence spectra of crystalline ortho-bromobenzophenone (2-bromobenzophenone, 2BrBP) were measured from 1.6 K to room temperature. A cardinal emission mechanism crossover occurs within this temperature range. At low temperature the phosphorescence spectrum is a superposition of two similar sets of equidistant bands spaced by the C=O stretch frequency. We ascribe these two sets to the emission of two different conformers, one of which is metastable and do not manifest itself above approximately 70 K. Presence of two conformers is explained by the fact that the 2BrBP molecule deforms considerably upon excitation. The emission from the stable conformer survives up to approximately 140 K or even higher. At roughly 60 K and higher, another type of emission reveals itself in the shape of a two very broad partly overlapping bands, which gains in intensity with increasing temperature. Above 150 K only this two-hump feature is observed in phosphorescence spectra. Additional phosphorescence experiments were carried out to elucidate the nature of this spectrum, including phosphorescence measurements of 2BrBP in ethanol solutions as well as time-resolved and varying-excitation-intensity measurements from crystals. Based on results of all the experiments reported here and on our own single-crystal x-ray structure data we conclude that the above two-band spectrum recorded near room temperature is due to the emission of single-photon bimolecular triplet excimer formed by the carbonyl groups of two neighbor 2-bromobenzophenone molecules. It is got the first time that a bimolecular excimer has been observed and reliably identified in a benzophenone derivative solid

    Photoinduced absorption and anomalous dichroism in NaCa₂Mn₂V₃O₁₂ garnet as an evidence for the formation of oxygen holes dynamics

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    It is shown that long-lived photoinduced dichroism in garnets is caused by photoproduced charges with anisotropic structure, keeping long memory of the pumping light polarization, while photoinduced absorption is due to all photoproduced charges irrespective of their intrinsic structure. The charges with anisotropic structure are identified as two-center oxygen holes. The formation of an oxygen hole is preceded by the excitation of a charge-transfer state with electron partially transferred to a cation C (V⁵⁺ for NaCa₂Mn₂V₃O₁₂ garnet) from an adjacent oxygen anion. To turn this excited state into a free hole state requires some time τhole during which the hole axis can be reoriented resulting in a diminution of dichroism. The time τhole shortens with increasing ionization potential of the cation C (very high for V⁵⁺). Such a mechanism explains qualitatively a set of unusual experimental facts, in particular, a very strong dichroism observed just in the NaCa₂Mn₂V₃O₁₂ garnet, where photoinduced changes of all optical properties disappear after switching off of the irradiation significantly faster than those in other garnets examined

    Spontaneous magnetostriction in the Gd-Y system: analysis of phase transformations

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    The transformations of magnetic and lattice subsystems states of Gd₁₀₀₋xYx (x=0, 5.5, 7.5, 10.2) alloys have been studied at temperatures 5-370 K in magnetic fields up to 4 kOe. The temperature dependences of elastic modules, thermal expansion, low field magnetization and magnetic anisotropy parameters were obtained. The linear spontaneous striction ΔL(T)/L=xh² was analized, and the effective order parameters η and magnetostrictive parameters ξ were evaluated for the four magnetic phases (canted ferromagnetic, deforming ferromagnetic helix, ferromagnetic helix, and the ferromagnetic cone, respectively): ξcf=2.2×10⁻⁵, ξdh=- 5.3×10⁻⁵, ξfh=7.1×10⁻⁵, ξfc=1.4×10⁻³

    Negative thermal expansion of HTSC-type structures: low temperature structure measurements on Eu₁₊x(Ba₁₋yRy) ₂₋xCu₃O₇₋d compounds and theoretical treatment

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    The temperature dependences of the lattice parameters were investigated on the perovskite-like structures Eu₁₊x(Ba₁₋yRy) ₂₋xCu₃O₇₋d with Ba substitution by light rare earth, using x-ray diffraction techniques. A negative thermal expansion effect was observed and explained in detail
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