Calculations of AC magnetic losses from the experimental field profiles in various types of coated conductors under applied fields

Yoo, J,Lee, S,Jung, Y,Lee, J,Youm, D,Ha, H,Kim, H,Ko, R-K,Oh, S Institute of Physics 2008 Journal of physics. Conference series Vol.97 No.1

<P>We measured the field profiles, <I>H</I>(<I>x,H</I><SUB>a</SUB>) s, near the surface of coated conductors (CCs) by using the scanning Hall probe method. The samples were SmBCO-CC tape fabricated by co-evaporation method and YBCO-CC tape fabricated by PLD method. The applied fields, <I>H</I><SUB>a</SUB>s, were decreased from <I>H</I><SUB>peak</SUB>to -<I>H</I><SUB>peak</SUB> stepwise. From the values of <I>H</I>(<I>x,H</I><SUB>a</SUB>), we calculated the current profiles, <I>J</I>(<I>x,H</I><SUB>a</SUB>) s, by the inversion method. From the values of <I>J</I>(<I>x,H</I><SUB>a</SUB>) and the corresponding flux densities, we calculated the hysteretic energy losses per cycle, <I>Q</I><SUB>M</SUB>s, for various <I>H</I><SUB>peak</SUB>s. From the values of <I>Q</I><SUB>M</SUB>, we calculated the characteristic functions, <I>g</I>s, by using the relation, <I>g</I>= π<I>Q</I><SUB>M</SUB>/μ<SUB>0</SUB><I>I</I><SUP>2</SUP><SUB>c</SUB>. Here, <I>I</I><SUB>c</SUB> is the critical current. For the range of <I>H</I><SUB>peak</SUB>/<I>H</I><SUB>c</SUB>≤ 3, the <I>g</I>-values of SmBCO CC tape were larger than those of YBCO CC tape. However, for the range of <I>H</I><SUB>peak</SUB>/<I>H</I><SUB>c</SUB> ≥ 3, the <I>g</I>-values of SmBCO CC tape were smaller than those of YBCO CC tape. When <I>H</I><SUB>peak</SUB>/<I>H</I><SUB>c</SUB> = 3, both sample show almost same value of <I>g.</I>However we found qualitatively different <I>J–B</I> hysteretic curves for both samples. We also compared our <I>g</I>-values with other <I>g</I>-values, which were directly measured by energy loss experiments. Our <I>g</I>-values of YBCO CC tapes were basically similar to the Brandt's theoretical values of <I>g</I> in the most range of <I>I</I><SUB>peak</SUB> in our measurements.</P>

Wall stretch and thromboxane A2 activate NO synthase (eNOS) in pulmonary arterial smooth muscle cells via H2O2 and Akt-dependent phosphorylation

Kim, H. J.,Yoo, H. Y.,Jang, J. H.,Lin, H. Y.,Seo, E. Y.,Zhang, Y. H.,Kim, S. J. Springer Science + Business Media 2016 Pfl ugers Arch Vol.468 No.4

<P>Pulmonary arteries (PAs) have high compliance, buffering the wide ranges of blood flow. Here, we addressed a hypothesis that PA smooth muscle cells (PASMCs) express nitric oxide synthases (NOS) that might be activated by mechanical stress and vasoactive agonists. In the myograph study of endothelium-denuded rat PAs, NOS inhibition (L-NAME) induced strong contraction (96 % of 80 mM KCl-induced contraction (80K)) in the presence of 5 nM U46619 (thromboxane A(2) (TXA(2)) analogue) with relatively high basal stretch (2.94 mN, S(+)). With lower basal stretch (0.98 mN, S(-)), however, L-NAME application following U46619 (TXA(2)/L-NAME) induced weak contraction (27 % of 80K). Inhibitors of nNOS and iNOS had no such effect in S(+) PAs. In endothelium-denuded S(+) mesenteric and renal arteries, TXA(2)/L-NAME-induced contraction was only 18 and 21 % of 80K, respectively. Expression of endothelial-type NOS (eNOS) in rat PASMCs was confirmed by RT-PCR and immunohistochemistry. Even in S(-) PAs, pretreatment with H2O2 (0.1-10 mu M) effectively increased the sensitivity to TXA(2)/L-NAME (105 % of 80K). Vice versa, NADPH oxidase inhibitors, reactive oxygen species scavengers, or an Akt inhibitor (SC-66) suppressed TXA(2)/L-NAME-induced contraction in S(+) PAs. In a human PASMC line, immunoblot analysis showed the following: (1) eNOS expression, (2) Ser(1177) phosphorylation by U46619 and H2O2, and (3) Akt activation (Ser(473) phosphorylation) by U46619. In the cell-attached patch clamp study, H2O2 facilitated membrane stretch-activated cation channels in rat PASMCs. Taken together, the muscular eNOS in PAs can be activated by TXA(2) and mechanical stress via H2O2 and Akt-mediated signaling, which may counterbalance the contractile signals from TXA(2) and mechanical stimuli.</P>

Effects of HA and NA glycosylation pattern changes on the transmission of avian influenza A(H7N9) virus in guinea pigs

Park, S.,Lee, I.,Kim, J.I.,Bae, J.Y.,Yoo, K.,Kim, J.,Nam, M.,Park, M.,Yun, S.H.,Cho, W.I.,Kim, Y.S.,Ko, Y.Y.,Park, M.S. Academic Press 2016 Biochemical and biophysical research communication Vol.479 No.2

Avian influenza H7N9 virus has posed a concern of potential human-to-human transmission by resulting in seasonal virus-like human infection cases. To address the issue of sustained human infection with the H7N9 virus, here we investigated the effects of hemagglutinin (HA) and neuraminidase (NA) N-linked glycosylation (NLG) patterns on influenza virus transmission in a guinea pig model. Based on the NLG signatures identified in the HA and NA genetic sequences of H7N9 viruses, we generated NLG mutant viruses using either HA or NA gene of a H7N9 virus, A/Anhui/0½013, by reverse genetics on the 2009 pandemic H1N1 virus backbone. For the H7 HA NLG mutant viruses, NLG pattern changes appeared to reduce viral transmissibility in guinea pigs. Intriguingly, however, the NLG changes in the N9 NA protein, such as a removal from residue 42 or 66 or an addition at residue 266, increased transmissibility of the mutant viruses by more than 33%, 50%, and 16%, respectively, compared with a parental N9 virus. Given the effects of HA-NA NLG changes with regard to viral transmission, we then generated the HA-NA NLG mutant viruses harboring the H7 HA of double NLG addition and the N9 NA of various NLG patterns. As seen in the HA NLG mutants above, the double NLG-added H7 HA decreased viral transmissibility. However, when the NA NLG changes occurred by a removal of residue 66 and an addition at 266 were additionally accompanied, the HA-NA NLG mutant virus recovered the transmissibility of its parental virus. These demonstrate the effects of specific HA-NA NLG changes on the H7N9 virus transmission by highlighting the importance of a HA-NA functional balance.

CSA계 혼합 시멘트 수화에 미치는 Boric Acid 의 영향

유광석,이경희,김남호,이양수,안광훈,이재원,임굉,Yoo, K.S.,Lee, K.H.,Kim, N.H.,Lee, Y.S.,Hun, K.H.,Lee, J.W.,Yim, Going 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.6

C1A3계 속경성 혼합시멘트에 대한 H3BO3의 첨가에 따른 mortar의 물성과 수화 생성물에 관한 연구를 하였다. H3BO3의 첨가는 응결 시간의 지연과 흐름성의 개선을 가져 왔다. H3BO3의 첨가에 따라 초기 수화 생성물은 monosulfate가 생성 되며 이 생성물이 존재하는 기간도 길어진다. 일단 monosulfate가 생성되면 그후 ettringite로 변화되면서 중간 단계로 gel상의 물질로 변화된다. 초기에 생성되어지는 monosulfate는 mortar의 응결시간과 flow에 영향을 준다. The study was carried on the influence of {{{{ { {H }_{3 }BO }_{3 } }} for hydration of blended rapid hardening cement which was composed of {{{{ {{C }`_{4 } ^{ }A }_{3 } }} Adding {{{{ { {H }_{3 }BO }_{3 } }} to the mortar of blended rapid hardening cement delayed the setting time and increased the flow of the mortar. When {{{{ { {H }_{3 }BO }_{3 } }} added to the blended rapid hardening cement mono-sulfate was produced rather than ettringite and the existing time of monosulfate also prolonged. After hours monosulfate was converted to ettringite through being producted like gels. This monosulfate phase in-fluences on the setting time and flow of fresh mortar.

Effect of the Length of Feed Withdrawal on Weight Loss, Yield and Meat Color of Broiler

Kim, D.H.,Yoo, Y.M.,Kim, S.H.,Jang, B.G.,Park, B.Y.,Cho, S.H.,Seong, P.N.,Hah, K.H.,Lee, J.M.,Kim, Y.K.,Hwang, I.H. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.1

The current study was conducted to determine the optimum length of feed withdrawal for pre-harvest broilers. A total of three hundred broilers were sampled from an industrial population, and 30 chicks for each weight group (e.g., 1.5 and 2.5 kg) were randomly assigned to feed withdrawal treatments for 0, 3, 6, 9 and 12 h. Weight loss, yield, muscle pH, objective meat color and weights of gastro intestinal contents, crop, gizzard, provenriculus, small intestine, caecum, and rectum were determined. Live weight loss was significantly (p<0.05) increased as length of feed withdrawal extended. A significant (p<0.05) carcass yield for both 1.5 and 2.5 kg groups coincided after 9 and 6 h feed withdrawal, respectively. Net weights of intestinal contents for crop and gizzard were significantly (p<0.05) reduced by 6 h, and the reduction for proventriculus and small intestine occurred from 3 h. A noticeable effect of feed withdrawal on pH for breast muscle at 3 h postmortem occurred only when chicks were fasted for 3 h of which pH (6.05) was significantly (p<0.05) higher than that for other groups including the control (5.74). There was a linear tendency of higher lightness (Hunter L* value) numerically for chicks fasted for longer periods. The highest coefficient of determinations of regression models to estimate weight loss as a function of fasting period and body weights were achieved, when the models included both linear and quadratic terms for fasting period, and linear term for both 1.5 ($R^2=0.76$) and 2.5 kg ($R^2=0.78$) body weight groups. Given the practical aspect, approximately 1.5 kg of body weight is dominant, weight loss could be predicted by the following function; live weight $loss=26.6-0.28{\times}(fasting period)^2+12.34{\times}pasting\;period-0.012{\times}body\;weight$, $R^2=0.76$. Current data implied that the optimum fasting time for pre-slaughter chicks varied depending on slaughter weight; 6 and 9-h fasting were recommendable for 2.5 and 1.5 kg chicks, with little effect on objective meat color.

과산화수소가 함유된 저산도 질산용액에서 DEHPA 추출제에 의한 Np 의 추출거동

이일희,양한범,김광욱,임재관,유재형 ( E . H . Lee,H . B . Yang,K . K . Kim,J . K . Lim,J . H . Yoo ) 한국공업화학회 1996 공업화학 Vol.7 No.4

본 연구는 Np의 환원제로 H₂O₂가 함유된 IM 이하의 저산도 질산용액으로부터 DEHPA(di-(2-ethyhexyl)phosphoric acid) 추출제에 의한 Np의 추출 및 역추출 조건 설정과 추출속도 향상에 주안점을 두어, 회분식으로 실험을 수행하였다. 저산도 질산용액에서 Np의 산화상태는 주로 Np(V)로 존재하고 있음을 확인하였으며, NP의 추출율은 H₂0₂농도 및 DEHPA의 농도 증가에 따라 증가하고, 질산농도 증가에 따라 급격히 감소하였다. 제3의 산화/환원제가 첨가되지 않는 경우 추출율은 약 70% 정도로 다소 낮지만, DEHPA에 의해 추출이 가능함을 보았다. 또한 추출속도는 H₂O₂농도의 0.516 승에 비례하며, 질산농도의 0.483 승에 반비례하고 있는 다음과 같은 식을 얻었다. d[Np(V)]/dt=-1.391×10^(-2)[H₂O₂]^(0.516)[HNO₃]^(-0.483) [Np(V)] 그리고 과산화수소의 첨가 유무에 관계없이, 유기상으로 추출된 Np은 옥살산(oxalic acid)에 의해 효과적으로 역추출되었으며, 0.5M 옥살산으로 약 92% 이상을 역추출하였다. Extraction behaviour of Np with DEHPA(di-(2-ethyhexyl) phosphoric acid) from the low nitric acid solution(below 1M HNO₃) containing H₂O₂as a reducing agent was studied at a batch system in order to establish the conditions of extraction and stripping and to enhance the extraction rate. As results, it was confirmed that the Np was mainly the pentavalent oxidation state in the low nitric acid solution. The extraction yield of Np was increased with increasing the concentration of DEHPA and H₂O₂and decreased more rapidly with the increase of HNO₃ concentration. It was also found that the Np could be extracted into DEHPA even without the addition any redox agents, although the extraction yield is rather low as about 70%. The extraction rate was proportional to the 0.516 power of H₂O₂concentration and inversely proportional to 0.483 power of HNO, concentration as follows. d[Np(V)]/dt=-1.391×10^(-2)[H₂O₂]^(0.516)[HNO₃]^(-0.483) [Np(V)] Regardless of the H₂O₂, the Np extracted in the organic phase was effectively stripped to the aqueous phase with H₂C₂O₄. The Np could be stripped more than 92% with 0.5M H₂C₂O₄.

Validation of egg yolk antibody based C-ELISA for avian influenza surveillance in breeder duck

Jeong, O.M.,Kim, M.C.,Kang, H.M.,Ha, G.W.,Oh, J.S.,Yoo, J.E.,Park, C.H.,Kwon, J.S.,Pack, M.R.,Kim, H.R.,Kim, Y.J.,Kwon, J.H.,Lee, Y.J. Elsevier Scientific Pub. Co 2010 Veterinary microbiology Vol.144 No.3

Active surveillance for avian influenza virus (AIV) has expanded from chicken to various poultry species including duck. To further effective antibody screening in laying breeder ducks, we validated the egg yolk antibody as alternative source to serum for AIV antibody. Sera and eggs were collected at weekly intervals after two types of AIV vaccination, H5N3 and H9N2. The antibody levels were determined by an agar gel immunodiffusion (AGID) test, haemagglutination inhibition (HI) test and the competitive enzyme-linked immunosorbent assay (C-ELISA). AGID test did not detect antibodies in egg yolk, and the agreement between AGID test and either HI test or C-ELISA in serum was slight and fair based on kappa statistics (kappa value (κ)@?0.19 in H5N3 group and κ@?0.37 in H9N2 groups). However, there was almost perfect agreement between HI test and C-ELISA (κ>0.9 in all group). The C-ELISA was as sensitive and specific as the HI test, and could be used as a pre-screening test for the detection of type A avian influenza virus antibody. Comparison was made between egg yolk and serum antibody titers by a regression analysis. A high correlation was observed between serum and yolk antibody titers (r=0.8762 for H5N3 and 0.8914 for H9N2 in HI test; r=1 for H5N3 and 0.9686 for H9N2 in ELISA test), although egg yolk antibodies were detected later and remained lower levels than serum antibodies. In field trials involving 54 duck flocks, the positive rate of egg yolk and serum samples showed agreement for the detection of AIV antibody. We concluded that as an alternative to serum, antibody monitoring of laying breeder duck using egg yolk with C-ELISA is feasible and is recommended.

Iron oxide/porous carbon as a heterogeneous Fenton catalyst for fast decomposition of hydrogen peroxide and efficient removal of methylene blue

Yoo, S.,Jang, D.,Joh, H. I.,Lee, S. Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.2

<P>A high performance Fe3O4/Fe/Fe3C@PCNF heterogeneous Fenton catalyst was synthesized for aqueous H2O2 decomposition and was utilized to remove methylene blue in water. Surprisingly, Fe3O4/Fe/Fe3C@PCNF showed an extremely fast decomposition rate; this rate ranked as the highest value reported to date. Furthermore, it showed efficient removal of methylene blue in water which was tested at different H2O2 concentrations and solution temperatures. Based on detailed characterization, several unique features of this catalyst were presumed to be responsible for its remarkable catalytic activity for H2O2 decomposition as follows: (1) the presence of Fe-0 and delocalized pi-electrons of graphitic layers promotes the reduction of Fe3+ to Fe2+; (2) the catalyst particles were partially covered with a few defective graphitic layers, and H2O2 decomposition could occur through these defects; (3) the defective graphitic layers partially covered the catalyst particle to force the decomposition reaction to occur only in the vicinity of carbon and Fe3O4. Finally, this presumption was proved through experiments by changing the activation time of Fe3O4/Fe/Fe3C@PCNF. After H2O2 decomposition was completed, Fe3O4/Fe/Fe3C@PCNF could be efficiently separated by an external magnetic field because of its ferromagnetic behavior. Fe3O4/Fe/Fe3C@PCNF showed high removal activity of aqueous methylene blue tested under various conditions.</P>

Triazole-bridged magnetic M(II) assemblies (M=Co, Ni) capped with the end-on terephthalate dianion involving multi-intermolecular contacts

Yoo, H.S.,Lim, J.H.,Kang, J.S.,Koh, E.K.,Hong, C.S. Pergamon Press 2007 Polyhedron Vol.26 No.15

Two dimeric complexes [M<SUB>2</SUB>(atrz)<SUB>3</SUB>(H<SUB>2</SUB>O)<SUB>4</SUB>(tp)<SUB>2</SUB>].11H<SUB>2</SUB>O [M=Co(1.11H<SUB>2</SUB>O), Ni(2.11H<SUB>2</SUB>O); tp=terephthalate, atrz=4-aminotriazole] were constructed by triply-bridged triazole ligands and terminal tp groups. Among the dinuclear assemblies, three types of intermolecular interactions (hydrogen bond, face-to-face π-π and edge-to-face CH-π contacts) as well as intramolecular hydrogen bonding are involved, eventually leading to the formation of a 3D network. Magnetic data show that moderate antiferromagnetic interactions between two metal centers communicate through triazole groups and non-negligible interdimer antiferromagnetic couplings are also involved in this system.

A numerical investigation of hydrogen desorption phenomena in ZrCo based hydrogen storage beds

Yoo, H.,Ko, J.,Yun, S.h.,Chang, M.h.,Kang, H.g.,Kim, W.,Ju, H. Pergamon Press ; Elsevier Science Ltd 2013 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.38 No.14

In this paper, a three-dimensional (3D) hydrogen desorption model is applied to the thin double layered annulus ZrCo based hydrogen storage bed to precisely study the hydrogen desorption reaction and resultant heat and mass transport phenomena inside the bed. The 3D hydrogen desorption simulations are carried out and calculated results are compared with the experimental data measured by Kang et al. [1]. The present model reasonably captures the bed temperature evolution behavior and the hydrogen discharging time for 90% desorption. In addition, the thin double layered annulus metal hydride bed (MHB) design is numerically evaluated by comparing with a simple cylindrical MHB. More uniform distributions in the bed temperature and H/M atomic ratio and resultant superior hydrogen desorption performance are achieved with the thin double layered annulus bed owing to its high external surface to volume ratio and thus more efficient heating. This numerical study indicates that efficient design of the metal hydride bed is key to achieve rapid hydrogen discharging performance and the present 3D hydrogen desorption model is a useful tool for the optimization of bed design and operating conditions.