http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
REBCO coil operation in gaseous helium and solid nitrogen
Diev, D.N.,Makarenko, M.N.,Naumov, A.V.,Polyakov, A.V.,Shcherbakov, V.I.,Shutova, D.I.,Surin, M.I. The Korea Institute of Applied Superconductivity a 2019 한국초전도저온공학회논문지 Vol.21 No.3
The paper gives the results of the experiments with a model two-section REBCO solenoid cooled by either gaseous helium (GHe) or sub-cooled/solid nitrogen (SN2) in (50-77) K temperature range. The major cooling source was a single-stage cryocooler Sumitomo CH-110 with the cooling power of 175 W and 130 W at 77 K and 50 K respectively. The coil itself was not directly conduction cooled. We compare the time taken by both coolants to obtain the temperature of the magnet of about 50 K and the homogeneity of the temperature distribution within the cryostat. Test results for the coil operation in solid nitrogen together with the comparison of its critical properties in SN2 and GHe are also presented.
Thanh, Tran Dang,Xuan Hau, Kieu,Huyen Yen, Pham Duc,Manh, T. V.,Yu, S. C.,Phan, T. L.,Telegin, A.,Telegin, S.,Naumov, S. IEEE 2018 IEEE transactions on magnetics Vol.54 No.11
<P>In this paper, we present a detailed analysis on the critical behavior of La<SUB>1.2</SUB>Sr<SUB>1.8</SUB>Mn<SUB>2</SUB>O<SUB>7</SUB> single crystal via isothermal magnetization measured at different temperatures around the paramagnetic–ferromagnetic phase transition at <TEX>$T_{C} = 85$</TEX> K. Using the Landau–Lifshitz coefficients, the Arrott plots ( <TEX>$H/M = a(T) + b(T)M^{2}$</TEX>) of sample have been analyzed. It showed that a(T) changed from positive to negative values at different temperatures in the field ranges of <TEX>$H = 0$</TEX>–10, 10–30, and 30–50 kOe, indicating that the critical behavior could not be described with a single model under different applied fields. Through the modified Arrott plots method, the Kouvel–Fisher method, and the critical isotherm analysis, we determined the values of the critical exponents for La<SUB>1.2</SUB>Sr<SUB>1.8</SUB>Mn<SUB>2</SUB>O<SUB>7</SUB> around its magnetic phase transition over different magnetic field ranges. The critical exponent <TEX>$\beta $</TEX> value is found to be 0.501, 0.417, and 0.371 under field ranges of <TEX>$H = 0$</TEX>–10, 10–30, and 30–50 kOe, respectively. This means that the <TEX>$\beta $</TEX> value depends strongly on the strength of the applied field, shifting from the value approaching that of the mean field model ( <TEX>$\beta = 0.5$</TEX>) to the 3-D-Heisenbeg model ( <TEX>$\beta = 0.365$</TEX>). Meanwhile, its <TEX>$\gamma $</TEX> value is quite stable ( <TEX>$\gamma =0.973$</TEX>–1.074), almost independent on the choice of field fitting range. In addition, using the reduced temperature <TEX>$\varepsilon = (T-T_{C}$</TEX>)/ <TEX>$T_{C}$</TEX> and the obtained critical exponents, almost <TEX>$M(H, T$</TEX>) data measured near <TEX>$T_{C}$</TEX> obey the scaling equation <TEX>$M(H, \varepsilon) = \varepsilon ^{\boldsymbol {\beta }}f_{\pm }(H/\varepsilon ^{\boldsymbol {\beta +\gamma }}$</TEX>), where <TEX>$f_{+}$</TEX> and <TEX>$f_{-}$</TEX> are regular analytic functions corresponding to data at <TEX>$T > T_{C}$</TEX> and <TEX>$T < T_{C}$</TEX>, respectively.</P>
REBCO coil operation in gaseous helium and solid nitrogen
D. N. Diev*,M. N. Makarenko,A. V. Naumov,A. V. Polyakov,V. I. Shcherbakov,D. I. Shutova,M. I. Surin 한국초전도.저온공학회 2019 한국초전도저온공학회논문지 Vol.21 No.3
The paper gives the results of the experiments with a model two-section REBCO solenoid cooled by either gaseous helium (GHe) or sub-cooled/solid nitrogen (SN2) in (50-77) K temperature range. The major cooling source was a single-stage cryocooler Sumitomo CH-110 with the cooling power of 175 W and 130 W at 77 K and 50 K respectively. The coil itself was not directly conduction cooled. We compare the time taken by both coolants to obtain the temperature of the magnet of about 50 K and the homogeneity of the temperature distribution within the cryostat. Test results for the coil operation in solid nitrogen together with the comparison of its critical properties in SN2 and GHe are also presented.
Zimin, S P,Gorlachev, E S,Mokrov, D A,Amirov, I I,Naumov, V V,Gremenok, V F,Juskenas, R,Skapas, M,Kim, W Y,Bente, K,Chung, Y-D IOP 2017 Semiconductor science and technology Vol.32 No.7
<P>In this work we report a phenomenon of the self-formation of nanostructure arrays during low-energy inductively coupled argon plasma treatment of the surface of copper indium gallium diselenide films grown by different methods on glass substrates. Selenization, pulsed laser deposition and multistage co-evaporation technological methods were used for the growth of polycrystalline CuIn<SUB>1−<I>x</I> </SUB>Ga<SUB> <I>x</I> </SUB>Se<SUB>2</SUB> (0.04?≤?<I>x</I>?≤?0.45) films. The plasma treatment of the surface of the films grown by all three methods resulted in the plasma-assisted self-formation of arrays of uniform cylindrical or conical nanostructures with the surface density of (0.8–1.8)?×?10<SUP>11</SUP> cm<SUP>−2</SUP>. Using scanning electron microscopy, transmission electron microscopy and atomic force microscopy, we describe the morphological parameters and chemical composition of the fabricated nanostructures and discuss possible physical mechanisms of the observed plasma-assisted nanostructuring.</P>
Magnetic and Magnetocaloric Properties of Ca0.97La0.03MnO3 Manganites
Gong, G. D.,Hu, P. F.,Li, Y.,Kim, D. H.,Liu, C. L.,Phan, T. L.,Ho, T. A.,Yu, S. C.,Telegin, A.,Naumov, S. V. Springer Science + Business Media 2016 Journal of electronic materials Vol.45 No.7
<P>In spite of many previous studies on electron-doped CaMnO3 perovskite manganites, detailed investigations into the influence of low-doping concentrations on their magnetic and magnetocaloric (MC) properties have not been carried out yet. Additionally, there is still the lack of the comparison between single-crystal (SC) and polycrystalline (PC) materials. Dealing with these problems, we prepared orthorhombic Ca0.97La0.03MnO3 SC and PC samples. Magnetization measurements versus the temperature and magnetic field revealed remarkable differences in the magnetic property, particularly around the antiferromagnetic/ferromagnetic-paramagnetic phase-transition region. The analyses of the magnetization versus magnetic field, M(H), data indicated a weak MC effect with magnetic-entropy changes less than 0.1 J kg(-1) K-1 for an applied field interval H = 10 kOe because ferromagnetic interactions between Mn3+ and Mn4+ ions are insignificant. The differences in the magnetic and MC properties of the SC and PC samples are ascribed to the effects of grain boundary, magnetic anisotropy, and nonstoichiometry in oxygen.</P>