Structural and electrical properties of Bi₂O₃-Nb₂O₅ thin films grown at low temperatures by pulsed laser deposition

Sun, J.W.,Kang, L.S.,Kim, J.S.,Joung, M.R.,Nahm, S.,Seong, T.G.,Kang, C.Y.,Kim, J.H. Elsevier Science 2011 Acta materialia Vol.59 No.14

The dielectric constant (ε<SUB>r</SUB>) of the films grown at 100<SUP>o</SUP>C increased as the beam energy density increased and a saturated value of 80 was obtained for the film grown under 6.0Jcm<SUP>-2</SUP>. The larger ε<SUB>r</SUB> value was attributed to the increased amount of nano-sized Bi<SUB>3</SUB>NbO<SUB>7</SUB> crystals. The ε<SUB>r</SUB> values also increased with the beam energy density for films grown at 300<SUP>o</SUP>C and a very high ε<SUB>r</SUB> value of 135.6 with a low loss of 3.0% at 100kHz was obtained for the film grown at 300<SUP>o</SUP>C under a beam density of 3.0Jcm<SUP>-2</SUP>. The crystalline BiNbO<SUB>4</SUB> phase developed, but the amount of Bi<SUB>3</SUB>NbO<SUB>7</SUB> crystals decreased as the beam energy density increased, indicating that the increased ε<SUB>r</SUB> values of the films grown at 300<SUP>o</SUP>C could be due to the formation of the crystalline BiNbO<SUB>4</SUB> phase. The electrical properties of the films grown at 300<SUP>o</SUP>C under a beam density of 3.0Jcm<SUP>-2</SUP> were considerably influenced by the oxygen partial pressure (OPP) during annealing. The film annealed at 300<SUP>o</SUP>C under a 50.0torr OPP exhibited a low leakage current density of 5.4x10<SUP>-9</SUP>Acm<SUP>-2</SUP> at 0.3MVcm<SUP>-1</SUP> with a relatively high breakdown field of 0.4MVcm<SUP>-1</SUP>1.

Discovery of a strange tribaryon S⁰(3115) in ⁴He(stopped ^K−,p) reaction

Suzuki, T.,Bhang, H.,Franklin, G.,Gomikawa, K.,Hayano, R.S.,Hayashi, T.,Ishikawa, K.,Ishimoto, S.,Itahashi, K.,Iwasaki, M.,Katayama, T.,Kondo, Y.,Matsuda, Y.,Nakamura, T.,Okada, S.,Outa, H.,Quinn, B. Elsevier 2004 Physics letters: B Vol.597 No.3

<P><B>Abstract</B></P><P>We have measured the proton energy distribution from the <SUP>4</SUP>He(stopped <SUP>K−</SUP>,p) reaction by means of time-of-flight. A mono-energetic peak was observed, which is interpreted as the formation of a new kind of neutral tribaryon S<SUP>0</SUP>(3115) with isospin T=1 and strangeness S=−1. The mass and width of the state were deduced to be 3117.0−4.4+1.5MeV/<SUP>c2</SUP> and <21MeV/<SUP>c2</SUP>, respectively. The state mainly decays into ΣNN.</P>

O-free polyacrylonitrile doping to improve the J_c(B) and H_c2 of MgB₂ wires

Hwang, S.M.,Sung, K.,Choi, J.H.,Kim, W.,Joo, J.,Lim, J.H.,Kim, C.J.,Park, Y.S.,Kim, D.H. North-Holland 2010 Physica. C, Superconductivity Vol.470 No.20

We selected polyacrylonitrile (PAN, -[C<SUB>3</SUB>H<SUB>3</SUB>N]-) as an O-free organic dopant and fabricated C-doped MgB<SUB>2</SUB> wires by in situ and powder-in-tube techniques. 0-5 wt.% PAN powders were uniformly mixed with B powder using a liquid mixing method. The precursor powders were mixed with Mg powder, filled into Fe tubes, and then drawn into wires. Sintering was performed at 900<SUP>o</SUP>C for 1h in a flowing Ar gas. The PAN doping decreased the critical temperature (T<SUB>c</SUB>) and a-axis lattice parameter, but significantly improved the critical current density (J<SUB>c</SUB>) in high fields, upper critical field (H<SUB>c2</SUB>), and irreversibility field (H<SUB>irr</SUB>) performances. These results are attributed to the replacement of B sites with C by the PAN doping. Furthermore, as expected, the MgO amount did not increase as the doping content increased. The J<SUB>c</SUB> of the PAN-doped MgB<SUB>2</SUB> wires was more than one order of magnitude higher than that of the undoped MgB<SUB>2</SUB> wire at 5K and 6.6T (1.46-3.82kA/cm<SUP>2</SUP> vs. 0.11kA/cm<SUP>2</SUP>).

Phase structure and electromechanical behavior of Li, Nb co-doped 0.95Bi_0.5Na_0.5TiO₃-0.05BaZrO₃ ceramics

Hussain, A.,Maqbool, A.,Malik, R.A.,Lee, J.H.,Sung, Y.S.,Song, T.K.,Kim, M.H. Elsevier 2017 CERAMICS INTERNATIONAL Vol.43 No.suppl1

In this work, the effect of Li, Nb co-doping on the structural phase, dielectric, ferroelectric and field induced strain behavior of 0.95Bi<SUB>0.5</SUB>Na<SUB>0.5</SUB>TiO<SUB>3</SUB>-0.05BaZrO<SUB>3</SUB> (BNT-BZ5) ceramic was investigated. X-ray diffraction patterns revealed the formation of single phase perovskite structure in the studied composition range. However, with increasing Li, Nb co-doping concentration, the maximum dielectric constant decreased and the dielectric maximum temperature (T<SUB>m</SUB>) slightly shifted towards higher temperature. The field induced strain response increased from 0.18% for pure BNT-BZ5 to 0.38% for 1mol.% Li, Nb modified BNT-BZ5 sample. The corresponding dynamic piezoelectric coefficient for these composition were (S<SUB>max</SUB>/E<SUB>max</SUB> = 257pm/V) and (S<SUB>max</SUB>/E<SUB>max</SUB> = 542pm/V), respectively. These results suggest that the BNLTN-BZ ceramic can be considered as a promising candidate material for piezoelectric application.

Comparing stochastic proton interactions simulated using TOPAS-nBio to experimental data from fluorescent nuclear track detectors

Underwood, T S A,Sung, W,McFadden, C H,McMahon, S J,Hall, D C,McNamara, A L,Paganetti, H,Sawakuchi, G O,Schuemann, J IOP 2017 Physics in medicine & biology Vol.62 No.8

<P>Whilst Monte Carlo (MC) simulations of proton energy deposition have been well-validated at the macroscopic level, their microscopic validation remains lacking. Equally, no gold-standard yet exists for experimental metrology of individual proton tracks. In this work we compare the distributions of stochastic proton interactions simulated using the TOPAS-nBio MC platform against confocal microscope data for Al<SUB>2</SUB>O<SUB>3</SUB>:C,Mg fluorescent nuclear track detectors (FNTDs). We irradiated <img ALIGN='MIDDLE' ALT='$8\times 4\times 0.5$ ' SRC='http://ej.iop.org/images/0031-9155/62/8/3237/pmbaa6429ieqn001.gif'/> mm<SUP>3</SUP> FNTD chips inside a water phantom, positioned at seven positions along a pristine proton Bragg peak with a range in water of 12 cm. MC simulations were implemented in two stages: (1) using TOPAS to model the beam properties within a water phantom and (2) using TOPAS-nBio with Geant4-DNA physics to score particle interactions through a water surrogate of Al<SUB>2</SUB>O<SUB>3</SUB>:C,Mg. The measured median track integrated brightness (IB) was observed to be strongly correlated to both (i) voxelized track-averaged linear energy transfer (LET) and (ii) frequency mean microdosimetric lineal energy, <img ALIGN='MIDDLE' ALT='$\overline{{{y}_{F}}}$ ' SRC='http://ej.iop.org/images/0031-9155/62/8/3237/pmbaa6429ieqn002.gif'/>, both simulated in pure water. Histograms of FNTD track IB were compared against TOPAS-nBio histograms of the number of terminal electrons per proton, scored in water with mass-density scaled to mimic Al<SUB>2</SUB>O<SUB>3</SUB>:C,Mg. Trends between exposure depths observed in TOPAS-nBio simulations were experimentally replicated in the study of FNTD track IB. Our results represent an important first step towards the experimental validation of MC simulations on the sub-cellular scale and suggest that FNTDs can enable experimental study of the microdosimetric properties of individual proton tracks.</P>

Effect of pressure on the corrosion and carburization behavior of chromia-forming heat-resistant alloys in high-temperature carbon dioxide environments

Lee, H.J.,Subramanian, G.O.,Kim, S.H.,Jang, C. Pergamon Press 2016 Corrosion science Vol.111 No.-

Chromia-forming heat-resistant alloys were corroded in atmospheric CO<SUB>2</SUB> (0.1MPa) and supercritical-CO<SUB>2</SUB> (S-CO<SUB>2</SUB>, 10 and 20MPa) at 550-650<SUP>o</SUP>C for 1000h. The weight gain and the extent of an amorphous C layer at the oxide/matrix interface increased with increasing CO<SUB>2</SUB> pressure from 0.1MPa to 20MPa, but the increase was mostly less than a factor of 2. Despite the huge difference in the test pressure, the depth of the carburized region with Cr-rich carbides was rarely affected for Alloy 800HT, resulting in similar tensile properties after corrosion in CO<SUB>2</SUB> and S-CO<SUB>2</SUB>.

A Study on the Seasonal Comparison of Dry Matter Intake, Digestibility, Nitrogen Balance and Feeding Behavior in Spotted Deer (Cervus nippon) Fed Forest By-products Silage and Corn Silage

Moon, S.H.,Jeon, B.T.,Kang, S.K.,Sung, S.H.,Hudson, R.J. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.1

The purpose of this experiment was to assess seasonal variation of feed utilization by feed sources and to obtain information on the use of feed resources by comparing seasonal changes of dry matter intake, digestibility, nitrogen balance and feeding behavior in spotted deer (Cervus nippon) fed forest by-product silage (FBS) and corn silage (CS). Dry matter intake (DMI) of FBS was higher than that of CS in both winter and summer. While DMI of both diets was higher in summer, this was not significant at the 5% level. In contrast to DMI, digestible dry matter intake (DDMI) was higher for CS than for FBS in both seasons, but the difference was not significant. Digestibility of dry matter and crude protein was significantly higher (p<0.01) for CS than for FBS, whereas digestibility of crude fiber was significantly higher (p<0.01) for FBS than for CS in both seasons. Seasonal digestibility of dry matter and crude fiber for FBS was significantly greater (p<0.01) in summer than in winter: In summer, seasonal digestibility was 57.2% for dry matter and 55.5% for crude fiber, and in winter, 50.8% for dry matter and 30.7% for crude fiber. On the other hand, seasonal digestibility of crude protein was higher (p<0.01) in winter (42.1%) than in summer (32.3%). No significant difference (p>0.05) was found between the two seasons and diets for nitrogen intake (NI), 18.7 g/d in summer and 19.4 g/d in winter for FBS, 17.7 g/d in summer and 17.7 g/d in winter for CS. Fecal nitrogen was higher (p<0.01) for FBS than for CS and varied little seasonally. There was significant difference (p<0.01) between two seasons in urinary nitrogen, which was little difference between two diets. Retained nitrogen (RN) was different significantly (p<0.01) between two diets in both seasons, but there was little difference between seasons. Deer usually spent longer time on eating FBS than eating CS. Eating FBS took 221 min in summer and 187 min in winter, whereas eating CS took 113 min in summer and 109 min in winter. Deer spent less time on eating food in winter than in summer. Time spent on rumination was longer for FBS than for CS: for FBS, 504 min in summer and 456 min in winter, for CS, 423 min in summer and 279 min in winter. Time varied seasonally with both diets.

저 탄소강의 오스테나이트 질화 시 암모니아 가스첨가 조건변화가 표면층 조직 및 기공변화에 미치는 영향

이제원 ( Jewon Lee ),노용식 ( Y. S. Roh ),성장현 ( J. H. Sung ),임수근 ( S. G. Lim ) 한국열처리공학회 2019 熱處理工學會誌 Vol.32 No.5

Low carbon steel (S20C steel) and SPCC steel sheet have been austenitic nitrided at 700℃ in a closed pit type furnace by changing the flow rate of ammonia gas and heat treating time. When the flow rate of ammonia gas was low, the concentration of residual ammonia appeared low and the hardness value of transformed surface layer was high. The depth of the surface layer, however, was shallow. With increasing the concentration of residual ammonia by raising up the ammonia gas flow, both the depth of the surface layer and the pore depth increased, while the maximum hardness of the surface layer decreased. By introducing a large amount of ammonia gas in a short time, a deep surface layer with minimal pores on the outermost surface was obtained. In this experiment, while maintaining 10~12% of residual ammonia, the flow rate of inlet ammonia gas, 7 liter/min, was introduced at 700℃ for 1 hour. In this condition, the thickness of the surface layer without pores appeared about 60 μm in S20C steel and 30 μm in SPCC steel plate. Injecting additional methane gas (carburizing gas) to this condition played a deteriorating effect due to promoting the formation of vertical pores in the surface layer. For 1^st transformed surface layer for S20C steel, maintaining 10~12% residual ammonia condition via austenitic nitriding process resulted in ε phase with relatively high nitrogen concentration (just below 4.23 wt.%N) among the mixed phases of ε+γ. The ε phase was formed a specific orientation perpendicular to the surface. For 2^nd transformed layer for S20C steel, γ phase was rather dominant (just above 2.63 wt.%N). For SPCC steel sheet, there appeared three phases, γ, α(M) and weak ε phase. The nitrogen concentration would be approximately 2.6 wt.% in these phases condition.

Effect of substrate on the phase transformation of TiO₂ in pearlescent pigment

Ryu, Y.C.,Kim, T.G.,Seo, G.S.,Park, J.H.,Suh, C.S.,Park, S.S.,Hong, S.S.,Lee, G.D. Korean Society of Industrial and Engineering Chemi 2008 Journal of industrial and engineering chemistry Vol.14 No.2

The TiO<SUB>2</SUB>/substrate pearlescent pigments were prepared by the hydrolysis of TiOCl<SUB>2</SUB> on the substrate followed by a calcinations process. The natural mica (muscovite), synthetic mica (fluorophlogopite) and α-alumina flake were selected as the substrates for pearlescent pigments. The effect of substrate on the anatase to rutile (A-R) phase transformation of TiO<SUB>2</SUB> was studied. The A-R phase transformation of TiO<SUB>2</SUB> during the preparation of pearlescent pigments and their proportion in the TiO<SUB>2</SUB> layer have been analyzed by XRD measurements. The phase compositions of TiO<SUB>2</SUB> layer in each pearlescent pigment are quite different depending on the substrates. The TiO<SUB>2</SUB> layer deposited on α-alumina has higher rutile fraction than those on the natural and synthetic mica. The XPS analysis showed that the cations originally present in the substrates diffused into the TiO<SUB>2</SUB> layer. The TiO<SUB>2</SUB> layer deposited on α-alumina contains Al, while those on the natural and synthetic mica substrates contain Si and K in addition to Al. The metal cations diffusing from the substrate into TiO<SUB>2</SUB> layer might retard the A-R phase transformation of TiO<SUB>2</SUB>. The suppressing effect on the A-R transformation of TiO<SUB>2</SUB> by mixed cations seems to be much stronger than that of single cation, resulting in relatively higher rutile fraction in the case of TiO<SUB>2</SUB> layer deposited on α-alumina.

GENEDIA Multi Influenza Ag Rapid Test for detection and H1, H3, and H5 subtyping of influenza viruses

Jang, J.W.,Ko, S.Y.,Byoun, M.S.,Sung, H.W.,Lim, C.S. Elsevier Science 2015 Journal of clinical virology Vol.73 No.-

Background: Rapid identification and subtype determination of influenza virus is important in managing infected patients. Rapid influenza diagnostic tests (RIDTs) are widely used in this manner, but most can only detect influenza A and B viruses without subtyping. A new RIDT, GENEDIA Multi Influenza Ag Rapid Test (GENEDIA), was developed for detection of influenza A and B viruses and also subtyping of influenza A to H1, H3, H5 which has not been possible with other RIDTs. Objectives: Assess the performance of GENEDIA. Study design: Nasopharyngeal swabs were collected from 274 clinically suspected patients (influenza A/H1N½009 (n=50), influenza A/H3 (n=50), influenza B (n=73) and influenza-negative (n=101)) and analyzed with the real-time RT-PCR, GENEDIA, SD Bioline Influenza Ag, and Alere BinaxNow Influenza A&B Card. Also, 46 fecal specimens (H5N2 (n=3), H5N3 (n=3)) of spot-billed duck were analyzed with RT-PCR and GENEDIA. Results: Compared to real-time RT-PCR, the sensitivities of GENEDIA, SD Bioline Influenza Ag, and Alere BinaxNow Influenza A&B Card were 73.0%, 57.0%, 58.0% for influenza A, respectively, and 68.5%, 65.8%, 57.5% for influenza B, respectively. Specifically, the sensitivity of GENEDIA was 70.0% for influenza A/H1N½009 and 76.0% for influenza A/H3. From the avian influenza samples, GENEDIA detected all six H5 subtype without any cross-reactions. Conclusion: The GENEDIA Multi Influenza Ag Rapid Test was sensitive in detecting influenza viruses compared with other commercial RIDTs and also useful for rapid subtype determination of influenza A.