3, 2020最新文献

{"title":"Counting Efficiency and Neutron/Gamma Ratio for KDP: Tl+ and UPS-923A Scintillators in a Single Photone Detection Mode","authors":"G. Onyshchenko, Ivan I. Yakymenko, B. Grynyov, V. Ryzhikov, O. Voronov, S. Naydenov","doi":"10.26565/2312-4334-2020-3-07","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-07","url":null,"abstract":"This research related to registration of the fast neutrons with a detector based on the inorganic KDP: TL+ mono crystal (KH2PO4 potassium dihydrogen phosphate) and plastic UPS-923A. The crystal of the KDP: TL+ detector grown from a water solution by the method of lowering the temperature. The high concentration of hydrogen nuclei in the KDP: TL+ crystal grid makes it possible to detect neutron radiation with an efficiency comparable to polystyrene scintillators. KDP: TL+ crystals have a high radiation resistance (up to 1010 neutrons/cm2), which significantly expands the spectrum of their application in high-energy physics applications, intense neutron fields. In this work, we used a technique for recording the detector response in the photon counting mode and pulse filtering mode. Since the detector operates on the principle of detecting gamma quanta from the reactions (n, n 'γ), (n, n' γ)res, (n, γ)cap and others, this makes it possible (in a filtering mode) to isolate the mechanisms of cascade generation processes in the volume of the detector caused by secondary gamma quanta from excited states of compound nuclei. The gamma quanta of the elastic scattering reaction (n, n' γ) for the KDP: TL+ scintillator nuclei are the start of the cascade process of the discharge of excited isomeric states of the input, intermediate, and final nuclei. Measurements of the detection efficiency of fast neutrons were carried out with a KDP: TL+ crystal of size 18x18x42 mm in spherical geometry. The obtained detector reviews in units of impulse / particle for sources and 239Pu-Be and 137Cs were 3.57 and 1.44. In this case, a broadband path with a speed of 7 ns was used. In addition, the counting efficiency of the narrow-band tract measured simultaneously with a processing time of 1 μs and 6.4 μs. The received response from the KDP: TL+ detector (in units of impulse/particle) for both sources 239Pu-Be and 137Cs was 0.09 and 0.00029. The n/γ ratio coefficient was 310. The given measurements of a polystyrene-based scintillator size of 40×40×40 mm. The received response in a single photon-counting mode from the plastic detector (in units of impulse/particle) for both sources 239Pu-Be and 137Cs was 19.4 and 3.9. The n/γ ratio coefficients for detectors are also given: KDP: TL+ - 2.47 and UPS-923A - 4.97 in the 7 ns mode. The statistical error in measurements of the neutron detection efficiency was about ~ 5%.","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129716589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure And Corrosion of Quasicrystalline Cast Al–Co–Ni and Al–Fe–Ni Alloys in Aqueous NaCl Solution","authors":"E. Sukhova, V. Polonskyy","doi":"10.26565/2312-4334-2020-3-01","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-01","url":null,"abstract":"In this work the structure and corrosion behavior of quasicrystalline cast Al69Co21Ni10 and Al72Fe15Ni13 alloys in 5-% sodium chloride solution (рН 6.9–7.1) were investigated. The alloys were cooled at 5 К/s. The structure of the samples was studied by methods of quantitative metallography, X-ray analysis, and scanning electron microscopy. Corrosion properties were determined by potentiodynamic method. Stationary potential values were measured by means of long-term registration of (Е,τ)–curves using\u0000ПІ–50–1 potentiostat and ПР–8 programmer with three-electrode electrolytic cell. A platinum electrode served as counter electrode and silver chloride – as reference electrode. The made investigations confirm the formation of stable quasicrystalline decagonal D-phase in the structure of Al69Co21Ni10 and Al72Fe15Ni13 alloys. In Al69Co21Ni10 alloy, at room temperature D-phase coexists with crystalline Al9(Co,Ni)2 phase, and in Al72Fe15Ni13 alloy – with Al5FeNi phase. Comparison of Vickers hardness of these phases exhibits the following sequence: H(D-AlCoNi)>H(D-AlFeNi)>H(Al5FeNi)>H(Al9(Co,Ni)2). In 5-% sodium chloride solution, the investigated alloys corrode under electrochemical mechanisms with oxygen depolarization. Compared with Al72Fe15Ni13 alloy, Al69Co21Ni10 alloy has more negative value of stationary potential (–0,40 V and –0,48 V, respectively), and its electrochemical passivity region extends due to the inhibition of anodic processes. For both alloys, transition to passive state in the saline solution is observed. A corrosion current density, calculated from (E,lgi)-curve, for Al69Co21Ni10 alloy amounts to 0.12 mА/сm2 and for Al72Fe15Ni13 alloy – to 0.14 mА/сm2. After immersion in the saline solution for 8 days, pits are revealed on the surface of the alloys in areas, mainly where the phase boundaries and flaws are located. The number and size of pits are smaller on the surface of Al69Co21Ni10 alloy as compared with those on the surface of Al72Fe15Ni13 alloy. The lower corrosion resistance of Al72Fe15Ni13 alloy may be explained by the presence of iron-containing phases in its structure. Based on obtained results, the Al69Co21Ni10 alloy has been recommended as coating material for rocket-and-space equipment working in marine climate.","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"207 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125893417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"System for Measuring Emittance Characteristics of Ion Sources","authors":"V. Voznyi, Mykola O. Sayko, A. Ponomarev, Serhii O. Sadovyi, O. Alexenko, R. O. Shulipa","doi":"10.26565/2312-4334-2020-3-06","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-06","url":null,"abstract":"The article presents the results of the development of a system for measuring emittance characteristics of ion sources studied at the IAP NAS of Ukraine with the aim of obtaining the ion beams with a high brightness. The emittance measurement system is based on the scheme of an electrostatic scanner and consists of two main parts: the scanner, which moves in the direction perpendicular to the beam axis using a stepper motor, and the electronic system of control, processing and data acquisition. The electronic system contains a Raspberry pi 3B microcomputer, precision DAC/ADCs, the high-voltage amplifier of a scanning voltage up to ±500 V on deflection plates of the scanner and a wide range current integrator. The determination of the emittance consists in measuring the ion beam intensity distribution when the scanner moves along the x-coordinate and the electrostatic scanning along the x´ angle. The obtained two-dimensional data array allows determining the main characteristics of ion beam: geometric 90% emittance, the root mean square (rms) emittance, the Twiss parameters and phase ellipse of rms emittance, the beam current profile and the angle current density distribution. To test the performance and functionality of the system, the emittance characteristics of the penning type ion source were measured. The working gas was helium, and the beam energy varied within 7–15 keV. At 13 keV of beam energy the following emittances of the He+ ions beam was obtained: 90% emittance is 30 π∙mm∙mrad, rms emittance is 8.4 mm∙mrad, and the normalized rms emittance is equal to 0.022 mm∙mrad. The developed system for measuring the emittance of the ion beams is characterized by a short measurement time of 10-15 minutes.","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116053284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and Characterization of TiO2 thin film Electrode based Dye Sensitized Solar Cell","authors":"Varsha Yadav, S. Chaudhary, S. Gupta, A. Verma","doi":"10.26565/2312-4334-2020-3-16","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-16","url":null,"abstract":"Dye-Sensitized Solar Cells (DSSCs) are prominent alternative devices to conventional p-n junction silicon based solar cells because of their low fabrication cost and high power conversion efficiency, good cost/efficiency ratio. In the present work, DSSC devices were made-up with fluorine doped tin oxide (FTO) glass substrate, a TiO2 compact layer was deposited on FTO, Ruthenium(II) dye (N719), an iodide - triiodide electrolyte and a platinum (Pt) counter electrode. Photo anode with thin film layers of TiO2 and Pt counter electrode (photo-cathode) were prepared. Field emission electron microscope (FESEM) was employed to investigate the surface morphology of TiO2 layers. The DSSC device efficiency was evaluated by J-V characteristics. Fabricated devices were exhibited high power conversion efficiencies. The electrochemical impedance characteristics were analyzed by fitting the experimental results to the corresponding electrical equivalent circuit simulated data.","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116950919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Binding of Benzanthrone Dye ABM to Insulin Amyloid Fibrils: Molecular Docking and Molecular Dynamics Simulation Studies","authors":"Kateryna Vus","doi":"10.26565/2312-4334-2020-3-18","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-18","url":null,"abstract":"The binding of the benzanthrone dye ABM to the model amyloid fibrils of human insulin, referred to here as vealyl (12-VEALYL-17, insulin B-chain)), lyqlen (13-LYQLEN-18, insulin A-chain) and Insf ( 11-LVEALYL-17, B-chain) + 12-SLYQLENY-19, A-chain) was studied by the molecular docking and molecular dynamics simulations. To obtain the relaxed structures with the enhanced conformational stability, the model fibril structures were solvated and equilibrated in water at 300-310 K using the Gromacs simulation package, with backbone position restraints being applied to prevent the beta-sheet disruption. It appeared that the vealyl fibril relaxation resulted in the twisting of the two β-sheets, and only the vealyl fibril remained stable during 20 ns MD simulations of the relaxed structures. Next, Insf, vealyl, lyqlen, and vealyl (relaxed) fibrils were used for the molecular docking studies (by SwissDock), revealing the binding modes of ABM and standard amyloid marker Thioflavin T (ThT) to the examined fibril structures. Specifically, in the most energetically stable complex the vealyl (relaxed) fibril binding site for ABM was located on the dry steric zipper interface, although the dye was associated with only one twisted β-sheet. During the 20 ns MD simulation the ABM fibril location was changed to a deeper position in the dry interface between the two β-sheets, with the dye-interacting residues being represented by 6 LEU, 3 VAL, 2 ALA, 1 TYR and 1 GLU. The binging free energy Δ(Gbinding) for ABM complexation with vealyl (relaxed) fibril evaluated with the GMXPBSA GROMACS tool was found to be –31.4±1.8 kJ/mol, that is in accordance with our estimates derived from the fluorescence studies for ABM binding to the bovine insulin amyloid fibrils Δ(Gbinding)= –30.2 kJ/mol. The Lennard-Jones component appeared to dominate the dye-fibril interactions, with much smaller contributions of Coulombic and nonpolar solvation terms to the total Δ(Gbinding) value, and unfavorable effect of the polar solvation term. These findings indicate that a high specificity of ABM to the insulin amyloid fibrils may arise predominantly from the dye-protein hydrophobic interactions, followed by the formation of van der Waals contacts, thus providing additional evidence for sensitivity of the dye spectral properties to environmental polarity, suggested in our previous studies. Overall, the obtained results provided further insights into the atomistic mechanism of the ABM binding to insulin amyloid fibrils and can be used for development of the novel fluorescent reporters possessing high sensitivity to the amyloid assemblies.","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"167 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114017862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First principles calculation of Manganese based half Heusler compounds","authors":"L. Mohan, Sukhender Sukhender, Sudesh Kumar, D. Sharma, A. Verma","doi":"10.26565/2312-4334-2020-3-15","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-15","url":null,"abstract":"The Half-Heusler compounds exhibit a diverse range of tuneable properties including half-metallic ferromagnetism topological insulator, solar cells and thermoelectric converters. We have studied four half-Heusler compounds MnFeIn, MnFeGa, MnNiAs and MnNiSb. The nature and properties of half-heusler compounds can be studied on the bases of their valance electron count. In this paper, Fe based compounds have 18 valence electrons; whereas 22 valence electrons in Ni based. The Density Functional Theory (DFT) has been performed with WIEN2k code. Ni based compounds with Mn located at octahedral sites are half-metals as revealed from the Density of States (DoS) and band structure calculations. In all of them, spin-up channels are conducting; whereas in MnNiAs and MnNiSb spin-down channels have the small band gaps. MnNiAs and MnNiSb exhibit half-metallic property with integer magnetic moments of 4 μB per formula unit and half-metallic gaps of 0.15 and 0.17 eV at their equilibrium volume respectively.","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121364243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of EBT3 Radiochromic Film Response in a High-Dose Range of 6 MV Photon and 6 MeV Electron Beams Using a Three-Color Flatbed Scanner","authors":"K. Duruer, D. Etiz, H. Yücel","doi":"10.26565/2312-4334-2020-3-02","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-02","url":null,"abstract":"Radiochromic film dosimetry has been commonly used for determination of dose measurement in radiotherapy for many years because of their high spatial resolution, low energy dependence and its approximate tissue equivalent. Additionally, it has other practical advantages, e.g.it is suitable for therapy range beam qualities, a water resistance material, a relatively insensitive to visible light, and does not need to make bathing process to obtain dose information. They are also independent to dose rate. Hence they are very useful and practical for clinical applications such as brachytherapy, electron therapy, skin dose measurements and stereotactic radiotherapy. Among them, the dynamic dose range of EBT3 radiochromic films are generally recommended for the dose range of 0.1 to 20 Gy. However, in this study, it is aimed to observe the behavior of EBT3 films in high dose range of up to 90 Gy under the irradiations. For this aim, the net optical densities were obtained with increasing dose values under photon and electron beams by employing three color scanning channel (red-green-blue). Thus, for making calibration curves, it was decided which color channel for EBT3 radiochromic film would be the most suitable one in different dose ranges. \u0000\u0000In experimental setup, the reference circumstances were first established and dose calibration procedure were carried out in RW3 phantom. Then the irradiated films were cut carefully into 2x2.5 cm2 pieces, and they were grouped into 2 as irradiation and control groups. The control group was waited for background, i.e. they are not irradiated. Before the irradiation, two groups of films have been scanned in flatbed scanner for three channels. After that, the irradiation group films was placed to align the exact place of effective point of ionization chamber under the reference condition. Later, they were irradiated one by one to up to 90 Gy with using 6 MV and 6 MeV beam qualities, respectively. Subsequently, both of film groups were again scanned in flatbed scanner for three –color channels.\u0000\u0000Optical densities and their standard deviations corresponding to the chosen dose values were obtained from the scanned films. Thus, calibration curves were plotted for all three colors channel according to two different beam conditions. The results obtained for 6 MV beam quality showed that if red color channel is selected for 0.9 Gy-7.3 Gy dose range, and green color channel is selected for 7.3 Gy-42.8 Gy dose range, and blue color channel is selected for 42.8 Gy-90.0 Gy dose range, the percentage uncertainty values in the obtained results are minimal. For the 6 MeV beam quality, if red color channel is selected for 0.9 Gy-7.7 Gy dose range, and green color channel is selected for 7.7 Gy-45.3 Gy dose range, and blue color channel is selected for 45.3 Gy-90.0 Gy dose range, the percentage uncertainty values in the obtained results are minimal.\u0000\u0000In conclusion, the percentage uncertainty values for the obtained results were eva","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129969650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Charmonium Properties","authors":"Tarek A. Nahoola, A. M. Yasserb, M. Anwara, G. A. Yahyaa","doi":"10.26565/2312-4334-2020-3-04","DOIUrl":"https://doi.org/10.26565/2312-4334-2020-3-04","url":null,"abstract":"We calculated the mass spectra of charmonium meson by using matrix method to make the predictions of ground and radially excited states of charmonium mesons via non-relativistic potential model. We compared our results with other theoretical approaches and recently published experimental data. The predictions are found to be in a good accordance with the latest experimental results of Particle data group and with the results of other theoretical approaches. Besides, we calculated the momentum width coefficients β of charmonium meson. Since, there are no experimental data for the momentum width coefficients β of charmonium meson yet. Consequently, our calculated coefficients β are compared with other theoretical studies and it is found to be in a good agreement with our results. The obtained results of coefficients β have implications for decay constants, decay widths and differential cross sections for charmonium system and generally for heavy mesons system. Our study is considered as theoretical calculation of some properties of charmonium meson.","PeriodicalId":199057,"journal":{"name":"3, 2020","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132714865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}