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Short-range magnetic order in La1-xBaxCoO3 cobaltites

  • Long, Phan The;Petrov, Dimitar N.;Cwik, J.;Dang, N.T.;Dongquoc, Viet
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1248-1254
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    • 2018
  • Magnetization versus temperature and magnetic-field measurements, M(T, $H_a$), have been carried out to study the magnetic and critical properties of polycrystalline $La_{1-x}Ba_xCoO_3$ (x = 0.3 and 0.5) cobaltites. These compounds with the density of ${\sim}6.2g/cm^3$ crystallized in the $R{\bar{3}}c$ rhombohedral and $Pm{\bar{3}}m$ cubic structures, respectively. With an applied field $H_a=200Oe$, M(T) data have revealed that the samples with x = 0.3 and 0.5 exhibit the ferromagnetic-paramagnetic (FM-PM) phase transition at the Curie temperature points $T_C=202$ and 157 K, respectively. At 4.2 K, the saturation magnetization ($M_{sat}$) decreases from 35.9 emu/g for x = 0.3-26.1 emu/g for x = 0.5. Particularly, the critical-behavior analyses in the vicinity of $T_C$ reveal all samples undergoing a second-order phase transition, with critical exponent values (${\beta}=0.328$ and ${\gamma}=1.251$ for x = 0.3, and ${\beta}=0.331$ and ${\gamma}=1.246$ for x = 0.5) close to those expected for the 3D Ising model. This proves short-range magnetic order existing in $La_{1-x}Ba_xCoO_3$. We believe that magnetic inhomogeneities due to the mixture of hole-rich FM regions (confined in the trivalent-cobalt hole-poor anti-FM matrix) and uniaxial anisotropy prevent long-range order in $La_{1-x}Ba_xCoO_3$.

DEVELOPMENT OF STRAW BASED RATION FOR FEEDING RUMINANTS

  • Kibria, S.S.;Islam, M.R.;Saha, C.K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.4 no.3
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    • pp.235-240
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    • 1991
  • A CRD experiment with thirty growing cross bred calves were assigned at random to three treatments rations. 1) $T_0$, 0% Urea + 20% M. O. cake, 2) $T_1$, 1% Urea + 10% M. O. cake and 3) $T_2$, 2% Urea + 0% M. O. cake to develop a rice straw based ration for ruminants. Sweetish odour and yellowish colour were observed in good recovered silage. Organic matter varied from 87.45% to 89.63% whereas crude protein varied from 14.0% to 14.5% in each treatment. No significant differences were found among the nutrient composition of the ration. The dry matter in take (DMI) and dry matter digestibility was higher in $T_0$ (0% Urea) than those of ration containing 1% ($T_1$) and 2% Urea ($T_2$). The organic matter digestibility decreases with increasing doses of urea. The crude protein & nitrogen-free-extract digestibility were found higher in the ration $T_1$ containing 1% urea whereas crude fibre digestibility and available metabolizable energy (ME) were higher in $T_0$ containing no urea as compared to $T_1$ and $T_2$. Total digestible nutrient (TDN) decreases with the increase of urea level. The highest feed efficiency was found in $T_0$ having no urea and lowest was in $T_2$. The animals gained in weights from each ration. Highest gain in weight was found in $T_0$ ration, then followed $T_1$, and $T_2$. This is due to natural protein available in M. O. cake only. It is concluded that supplemetation of urea or M. O. cake with readily available energy source as molasses upto 20% of total dietary dry matter in a complete ration may increase the intake of low quality fibrous roughage only when nitrogen and mineral are not limiting factor.

Effect of Diffusion on the Adhesion Behavior of Polymer Coated Carbon Fibers with Vinyl Ester Resins (계면확산에 의한 고분자 코팅된 탄소섬유의 계면접착력 변화 연구)

  • T. H. Yoon;H. M. Kang
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 1999.11a
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    • pp.32-35
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    • 1999
  • Poly(arylene ether phosphin oxide) (PEPO), Udel$^{\circledR}$ P-1700, Ultem$^{\circledR}$ 1000. poly(hydroxy ether) (PHE), carboxy modified poly(hydroxy ether)(C-PHE) and poly(hydroxy ether ethanol amine) (PHEA) were utilized for a coating of carbon fibers. Interfacial shear strength(IFSS) of polymers to carbon fibers was also evaluated in order to understand the adhesion mechanism. IFSS was measured via micro-droplet tests, and failure surfaces were analyzed by SEM. Diffusion between polymer and vinyl ester resin was investigated as a function of styrene content; 33. 40 or 50wt.% and the solubility parameters of polymers were calculated. The results were correlated to the interfacial shear strength. The highly enhanced interfacial shear strength (IFSS) was obtained with PEPO coating, and marginally improved IFSS with PHE, Udel$^{\circledR}$ and C-PHE coatings, but no improvement with PHEA and Ultem$^{\circledR}$ coatings.

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Quantity and Characteristics of Manure Produced by Holstein Heifer at Different Seasons (홀스타인 육성우의 계절별 분뇨 배설량 및 특성에 관한 연구)

  • Choi, D.Y.;Kwag, J.H.;Park, C.H.;Jeong, K.H.;Kim, T.I.;Kim, J.H.;Yoo, Y.H.;Yang, C.B.;Hong, H.L.
    • Journal of Animal Environmental Science
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    • v.12 no.3
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    • pp.123-132
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    • 2006
  • This study was conducted to determine the volume of Holstein heifers manure excreted and its characteristics. The average dry matter intake of heifers was 6.7 kg/head/day. The intake rate was lowest in spring among four seasons. The average dry matter intake rate during spring, summer, fall, and winter was 4.6, 8.3, 7.1, and 6.8 kg/head/day, respectively. The average water intake of heifers was $19.3{\ell}/head/day$. The wale. consumption was highest value ($21.8{\ell}/head/day$) in summer and lowest values ($18.3{\ell}/head/day$) in spring and winter. Values were found not to be statiscally different for the four seasons. The average manure production of heifers (average live weight was 363.1 kg) was 20.3 kg/head/day and it was 5.6% of live animal weight. The manure production during spring, summer, fall, and winter was 13.7, 23.5, 25.0, and 20.2 kg/head/day, respectively. Production during spring was lower than the other seasons (p<0.05). A higher correlation between live weight and manure production ($R^2=0.7816$) and between live weight and feed intake ($R^2=0.7296$) was observed for heifers. Correlations between manure production and water intake and between manure production and feed intake were found to be relatively low for heifers. The moisture content of feces was 83.5% and that of urine 94.6%. The pH of feces and urine were in the ranges of 7.4 and 7.5, respectively. The $BOD_5$, COD, SS, T-N, T-P concentrations of the heifer feces were 18,048, 50,114, 119,833, 2,519, and $427mg/{\ell}$, respectively. Heifer urine showed lower levels of $BOD_5(5,434mg/{\ell})$, COD$(6,550mg/{\ell})$, SS$(825mg/{\ell})$, T-N$(3,616mg/{\ell})$, and $T-P(28mg/{\ell})$ than feces. The fertilizer nutrient concentrations of heifer feces was 0.25% N, 0.1% $P_2O_5$ and 0.14% $K_2O$. Urine was found to contain 0.36% N, 0.006% of $P_2O_5$ and 0.31% $K_2O$.

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Simultaneous determinations of anthracycline antibiotics by high performance liquid chromatography coupled with radial-flow electrochemical cell (고성능 액체 크로마토그래피/방사흐름 전기화학전지를 이용한 안트라사이클린계 항생제의 동시 정량)

  • Cho, Yonghee;Hahn, Younghee
    • Analytical Science and Technology
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    • v.20 no.4
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    • pp.308-314
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    • 2007
  • The analytical method of HPLC with the radial-flow electrochemical cell (RFEC) has been developed to determine doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin simultaneously by employing a reversed-phase chromatography. Anthracyclines were detected at -0.74 V vs. a Ag/AgCl (0.01 M NaCl) reference electrode, a potential of diffusion current plateau in the mobile phase. At a $V_f$ of 1.0 mL/min doxorubicin, epirubicin, daunorubicin and idarubicin appeared at a retention time ($t_r$) of 6.4 min, 7.4 min, 12.7 min and 18.4 min, respectively, while at a $V_f$ of 0.6 mL/min, doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin appeared at a $t_r$ of 9.9 min, 11.5 min, 13.5 min, 19.6 min and 28.7 min, respectively. The linearity between each anthracycline injected ($2.40{\times}10^{-7}M{\sim}1.42{\times}10^{-5}M$) and peak area (charge) was excellent with the square of the correlation coefficient ($R^2$) higher than 0.999. The detection limits were $1.0{\times}10^{-8}M{\sim}1.5{\times}10^{-7}M$ for the five anthracyclines. Within-day precision for the five anthracyclines were in reasonable relative standard deviations less than 3 % ($1.00{\times}10^{-6}M{\sim}1.42{\times}10^{-5}M$) except the lower concentrations less than $0.7{\mu}M$. Solid phase extractions of $1.00{\times}10^{-5}M$ epirubicin, $0.48{\times}10^{-5}M$ nogalamycin and $1.52{\times}10^{-5}M$ daunorubicin from human serum with a $C_{18}$ cartridge resulted in 97 %, 100 % and 90 % of recoveries, respectively.

Acid Etching of Sapphire Substrate for Hetero-Epitaxial Growth (Hetero-Epi막 성장용 사파이어 기판의 산에칭)

  • Kim, Hyang Sook;Hwang, Jin Soo;Chong, Paul Joe
    • Journal of the Korean Chemical Society
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    • v.39 no.1
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    • pp.1-6
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    • 1995
  • The surface of a sapphire substrate used for hetero-epitaxy was chemically polished in a mixture of $H_3PO_4\;and\;H_2SO_4$ solution. The extent of etching for various crystal orientations was found to be dependent on the etching time at $315{\pm}2^{\circ}C$ and at the composition of $H_2SO_4 : H_3PO_4$=3 : 1. In addition, the etching rates of the substrates were investigated in the mixture of $H_2SO_4 : H_3PO_4$=3 : 1 by volume and in the temperature range of 280~320$^{\circ}C$. From the plot of log R against 1/T, the activation penergy ($(E_a)$) was found to be in the order of $({\bar1}012) > (10{\bar1}0) > (11{\bar2}0) > (0001)$ plane. After removing the surface layers of the sapphire with (0001), $({\bar1}012),\;(10{\bar1}0)\;and\;(11{\bar2}0)$ plane by a thickness of 64.6, 46.5, 16.2 and 5.1 ${\mu}m$, respectively, the morphology of the resulting surface was observed by SEM.

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Characteristic of Thermal Output of Thermally Activated Building System During the Heating Operation According to FDM Analysis (FDM 해석에 의한 구체축열시스템(TABS)의 난방운전시 방열 특성 분석)

  • Lim, Jae-Han;Song, Jin-Hee;Koo, Bo-Kyoung;Song, Seung-Yeong;Senog, Yoon-Bok
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.3
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    • pp.218-223
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    • 2012
  • This study is focused on the evaluation of thermal output of TABS (Thermally Activated Building System). The aim of this study is to evaluate TABS in terms of the temperature difference between heating medium supply temperature ($T_s$) and return temperature ($T_r$), thermal output and the surface temperature distribution according to the design flow rate and the design flow temperature. Through the transient heat transfer simulation using temperature calculation using Crank-Nicolson FDM using Physibel Voltra 6.0 W, the temperature difference between $T_s$ and ��$T_r$, thermal output and the surface temperature distribution of specific TABS was calculated and evaluated. The results show that specific thermal output and temperature difference at $60^{\circ}C$ of supply water temperature were about 162 $W/m^2$, $13.6^{\circ}C$ respectively.

The STAR RNA Binding Proteins SAM68, SLM-1 and SLM-2 Interact with Kinesin-I (Kinesin-I과 직접 결합하는 STAR RNA 결합 단백질인 SAM68, SLM-1과 SLM-2의 규명)

  • Seog, Dae-Hyun
    • Journal of Life Science
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    • v.21 no.9
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    • pp.1226-1233
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    • 2011
  • In neurons, kinesin is the molecular motor that transport cargos along microtubules. KIF5s (alias kinesin-I), are heterotetrameric motor conveying cargos, but the mechanism as to how they recognize and bind to a specific cargos has not yet been completely elucidated. To identify the interaction proteins for KIF5C, yeast two-hybrid screening was performed, and specific interaction with the $\underline{S}$am68-$\underline{l}$ike $\underline{m}$ammalian protein $\underline{2}$ (SLM-2), a member of the $\underline{s}$ignal $\underline{t}$ransducers and $\underline{a}$ctivators of $\underline{R}$NA (STAR) family of RNA processing proteins, was found. SLM-2 bound to the carboxyl (C)-terminal region of KIF5C and to other KIF5 members. The C-terminal domain of Sam68, SLM-1, SLM-2 was essential for interaction with KIF5C in the yeast two-hybrid assay. In addition, glutathione S-transferase (GST) pull-downs showed that SAM68, SLM-1, and SLM-2 specifically interacted to Kinesin-I complex. An antibody to SAM68 specifically co-immunoprecipitated SAM68 associated with KIF5s and coprecipitated with a specific set of mRNA. These results suggest that Kinesin-I motor protein transports RNA-associated protein complex in cells.

Synthesis of Alkylidyne Complexes of Br$(CO)_2(tmeda)M{\equiv}CC_{6}H_{4}Me$ (M = Cr, Mo, W). Crystal Structure of Br$(CO)_2(tmeda)M{\equiv}CC_{6}H_{4}Me$

  • Park, Joon T.;Cho, Jeong-Ju;Suh, Il-Hwan;Lee, Jin-Ho;Lim, Sung-Su;Ryu, Bo-Young
    • Bulletin of the Korean Chemical Society
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    • v.14 no.2
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    • pp.266-271
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    • 1993
  • The reaction of $(CO_5$)M=C(OMe)Tol (M=Cr, Mo, W and $Tol=p-C_6H_4Me)$ and $BBr_3$ followed by treatment with tetramethylethylenediamine (TMEDA) yields a mixture of two diastereomers, trans, $cis-Br(CO)_2(tmeda)M{\equiv}$CTol [M=Cr(1a), Mo(2a), W(3a)] and cis, $trans-Br(CO)_2(tmeda)M{\equiv}$CTol [M=Cr(1b), Mo(2b), W(3b)], respectively. These compounds have been isolated as crystalline solids and characterized by spectroscopic (infrared, mass, $^1H$ and $^{13}C-NMR)$ data. The trans, cis-Br(CO)2(tmeda)Cr${\equiv}$CTol (1a), has been examine via a single crystal X-ray diffraction study : $BrCrO_2N_2C_{16}H_{23}$, Mr=407.27, triclinic, $P{\bar{1}},\;a=12.792(2),\;b=13.400(5),\;c= 11.645(4)\;{\AA},\;{\alpha}=101.26(2)^{\circ},\;{\beta}=103.04(2)^{\circ},\;{\gamma}=91.88(2)^{\circ},\;{\nu}=1907(1){\AA}^3,\;Z=2,\;{\rho}(calcd)=1.418\;gcm^{-3},\;{\lambda}(MoK{\alpha})=0.71069\;{\AA},\;{\mu}=26.25 cm^{-1},\;F(000)=831.97,\;T=295K,\;R=0.0977$ for 1332 significant reflections $[F_0>5{\sigma}(F_0)]$. There are two essentially equivalent molecules in the crystallographic asymmetric unit. Each molecule is octahedral with the bromide ligand trans to the alkylidyne carbon, the two cis-carbonyl ligands, and the bidentate TMEDA ligand.