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>

CAN통신을 이용한 H-브릿지 멀티레벨 인버터의 PWM 동기화 및 위상전이 방법

박영민(Y.M.Park),유한승(H.S.Yoo),장성영(S.Y.Jang),이현원(H.W.Lee),이세현(S.H.Lee),서광덕(K.D.Seo) 전력전자학회 2004 전력전자학술대회 논문집 Vol.- No.-

H-브릿지 멀티레벨 인버터는 여러 개의 단상 Power Cell을 직렬로 연결함으로써 저전압 전력용 반도체를 사용하여 고전압을 얻을 수 있고, 정현파에 가까운 출력전압 파형을 얻을 수 있는 멀티레벨 인버터 토폴로지이다. 본 토폴로지는 출력전압 레벨에 비례하여 Power Cell의 수가 증가하므로, 주제어기의 연산능력에 대한 부담증가와 신호선의 많아지는 단점이 있다. 따라서 Power Cell제어를 직접적인 PWM 신호가 아닌 통신을 사용함으로써 이러한 단점을 극복할수 있으며, 신뢰성 측면이나 보수/유지 측면에서도 유리하다. 본 논문은 산업현장에서 신뢰성을 인정받아 많이 사용되고 있는 직렬통신 방식의 일종인 CAN통신 인터럽터를 이용한 H-브릿지 멀티레벨 인버터 Power Cell의 PWM 동기화 및 위상전이 방법에 관한 것이다. 제안된 방법의 주요 장점은 주제어기와 셀 제어기 사이에 직렬통신(CAN)을 사용함으로써 주제어기와 셀 제어기의 신호선의 단순화, 주제어기의 부담 감소, Power Cell의 모듈화, 셀 단위의 보호동작 용이, 확장성 향상 그리고 제어 신호 및 Power Cell의 신뢰성을 향상에 있다. 13레벨로 구성된 H-브릿지 멀티레벨 인버터 시험을 통해 제안된 방법의 타당성과 신뢰성을 입증하였다.

Early Activation of Phosphatidylinositol 3-Kinase after Ischemic Stroke Reduces Infarct Volume and Improves Long-Term Behavior

Kim, Y. S.,Yoo, A.,Son, J. W.,Kim, H. Y.,Lee, Y. J.,Hwang, S.,Lee, K. Y.,Lee, Y. J.,Ayata, C.,Kim, H. H. Humana Press 2017 Molecular Neurobiology Vol. No.

<P>Phosphatidylinositol 3-kinases (PI3Ks) have recently been implicated in apoptosis and ischemic cell death. We tested the efficacy of early intervention with a peptide PI3K activator in focal cerebral ischemia. After determining the most effective dose (24 mu g/kg) and time window (2 h after MCAO) of treatment, a total of 48 rats were subjected to middle cerebral artery occlusion (MCAO). Diffusion weighted MRI (DWI) was performed 1 h after MCAO and rats with lesion sizes within a predetermined range were randomized to either PI3K activator or vehicle treatment arms. Fluid attenuated inversion recovery (FLAIR) MRI, neurological function, western blots, and immunohistochemistry were blindly assessed. Initial DWI lesion volumes were nearly identical between two groups prior to treatment. However, FLAIR showed significantly smaller infarct volumes in the PI3K activator group compared with vehicle (146 +/- 81 mm(3) and 211 +/- 96 mm(3), p = 0.045) at 48 h. The PI3K activator group also had better neurological function for up to 2 weeks. In addition, PI3K activator decreased the number of TUNEL-positive cells in the peri-infarct region compared with the control group. Western blot and immunohistochemistry showed increased expression of phosphorylated Akt (Ser473) and GSK-3 beta (Ser9) and decreased expression of cleaved caspase-9 and caspase-3. Our results suggest a neuroprotective role of early activation of PI3K in ischemic stroke. The use of DWI in the randomization of experimental groups may reduce bias.</P>

Dipeptidyl petidase-IV inhibitor (gemigliptin) inhibits tunicamycin-induced endoplasmic reticulum stress, apoptosis and inflammation in H9c2 cardiomyocytes

Hwang, H.J.,Jung, T.W.,Ryu, J.Y.,Hong, H.C.,Choi, H.Y.,Seo, J.A.,Kim, S.G.,Kim, N.H.,Choi, K.M.,Choi, D.S.,Baik, S.H.,Yoo, H.J. North-Holland 2014 Molecular and cellular endocrinology Vol.392 No.1

The direct effects of dipeptidyl peptidase-IV (DPP-IV) inhibitors on endoplasmic reticulum (ER) stress-induced apoptosis and inflammation in cardiomyocytes have not been elucidated. H9c2 cell viability, which was reduced by tunicamycin, was increased after DPP-IV inhibitor gemigliptin treatment. Gemigliptin significantly decreased the tunicamycin-mediated increase in glucose regulated protein 78 (GRP78) expression and ER stress-mediated signaling molecules such as protein kinase RNA-like endoplasmic reticulum kinase (PERK)/C-EBP homologous protein (CHOP) and inositol-requiring enzyme 1α (IRE1α)/c-Jun N-terminal kinase (JNK)-p38. Furthermore, gemigliptin effectively induced Akt phosphorylation in a dose-dependent manner. Using flow cytometry and Hoechst staining, we showed that treatment with Akt inhibitor significantly blocked the anti-apoptotic effects mediated by gemigliptin. The reduction in tunicamycin-induced GRP78 level and PERK/CHOP pathway activity by gemigliptin was reversed after treatment with Akt inhibitor. In conclusion, gemigliptin effectively inhibited ER stress-induced apoptosis and inflammation in cardiomyocytes via Akt/PERK/CHOP and IRE1α/JNK-p38 pathways, suggesting its direct protective role in cardiovascular diseases.

The effects of Sm and Y addition on the properties of YBCO thin film prepared by a DCA-MOD method

Kim, B.J.,Yu, J.H.,Lee, J.B.,Yoo, Y.S.,Kim, J.G.,Lee, H.G.,Hong, G.W. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15

Off-stoichiometric (Y<SUB>1</SUB>RE<SUB>x</SUB>)Ba<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-δ</SUB>; (x=0-0.4, RE=Y or Sm) films have been prepared on LaAlO<SUB>3</SUB> (100) single-crystal substrates by a metal-organic deposition using dichloroacetic acid as chelating solution. Coating solutions with excess Sm or Y were prepared by dissolving Y, Sm, Ba and Cu acetates in dichloroacetic acid and distilled water followed by refluxing, drying to obtain blue gel. The final precursor solution for dip coating was prepared by diluting blue gel in 2-methoxyethanol. Coated films were calcined at low temperature up to 500<SUP>o</SUP>C in flowing humid oxygen atmosphere. Conversion heat treatment was performed at 800<SUP>o</SUP>C for 2h in flowing Ar gas containing 1000ppm oxygen with a humidity of 9.45%. The viscosities of the precursor solution were increased as the content of added Sm or excess Y increased. The transport critical current density (J<SUB>c</SUB>) of (Y<SUB>1</SUB>RE<SUB>x</SUB>)Ba<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-δ</SUB>; film was enhanced with the addition of excess Sm and Y up to 20% and then decreased with further addition. Scanning electron microscope (SEM) observation showed that surface roughness was increased with the addition of excess Y.

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 Egg Yolk Antibodies Produced in Response to Different Antigenic Fractions of E. coli O157:H7 on E. coli Suppression

Chae, H.S.,Singh, N.K.,Ahn, C.N.,Yoo, Y.M.,Jeong, S.G.,Ham, J.S.,Kim, D.W. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.11

The objective of this research was to provide the characterization and method for producing anti-E. coli O157:H7 antibodies in egg-laying hens and to determine if the antibody can restrain the proliferation of E. coli O157:H7 in-vitro. Selected antigenic fractions (whole cell, outer membrane protein and lipopolysaccharide (LPS)) from E. coli O157:H7 were injected to hens in order to produce anti-E. coli O157:H7 antibodies. The immune response and the egg yolk antibodies of laying hens against the whole cell, outer membrane protein and LPS antigens were monitored by ELISA. The level of antibodies against whole cell antigen monitored through ELISA sharply increased after the initial immunization, and it was found to be maximum on day 49 however, the level was maintained up to day 70. Antibodies (5 mg/ml) directed against the whole cell inhibited E. coli proliferation 10-13 times more than outer membrane protein or LPS. The antibody response against the whole cell antigens appeared to have higher activity in restraining the proliferation of E. coli O157:H7 than antibody against outer membrane protein or LPS. Results reflected that increasing the IgY's in the egg yolk could prevent greater economic losses due to human and animal health from pathogenic bacteria i.e. E. coli O157:H7.

셀프리더십에 따른 간호사의 직무만족도

강수연,김수연,도혜진,이혜선,전소현,전혜실,주원진,지윤정,진소희,이자형,정덕유,유소연 이화여자대학교 간호과학대학 2009 이화간호학회지 Vol.- No.43

In this study, we investigated how much job-satisfaction and self leadership nurses have. And making use of self leadership, we hope to enhance job- satisfaction and develop nurse organization. To find out the relationship between nurse's self leadership and Job-satisfaction, we carried out a sample survey : The subjects of our study are 150 nurses being in offices(hospitals) at the two university hospitals and three general hospitals in Seoul or Keong-gi province. Nurses agreed with and understood the purpose of our study. For analyzing the result, we used ANOVA of SPSS 14.0. The main results of our study are as follows : According to characteristic of subjects, level of self leadership has a meaningful difference statistically according to marriage, religion, department career, position. As for the marriage, the level of self leadership of the married are higher((F=19.95, p= .000) than the unmarried. . Level of self leadership perceived by subjects is an average 3.50 point. An average points of each factors are as follows : Self-compensation is 3.75 point, rehearsal is 3.57 point, self-expectation is 3.55 point, goal-setting is 3.53 point, self-criticism is 3.31 point, constructive thinking is 3.27 point. The total average is 62.9 point to 90 full marks. Level of self job-satisfaction perceived by subjects is an average 2.98 point to 5 full marks. Level of self job-satisfaction perceived by subjects is an average 2.98 point to 5 full marks. An average points of each factors are as follows : Interrelation is 3.42 point, interrelation between doctors and nurses is 3.35 point, job demand is 3.10 point, administration is 3.02 point, a professional position is 2.94 point, self control is 2.84 point, payment is 2.44 point. A coefficient of co-relation of self leadership and self job-satisfaction is .406 point, a meaning probability is .000 point and they seem to have a close interrelation. Rehearsal among factors of self leadership has the most interrelation with payment of self job-satisfaction. A professional position of self job-satisfaction has the most interrelation with self expectation(r= .314, p= .000). A job demand has the most interrelation with constructive thinking(r= .272, p= .001). A interaction has the most interrelation with self expectation(r= .272. p= .000). A administration has the most interrelation with constructive thinking(r= .411, p= .000). An interrelation between doctors and nurses has the most interrelation with self expectation(r= .385, p= .000). Our study shows there is a close relation between self leadership and job-satisfaction. Especially, self expectation and constructive thinking, the factor of self leadership, appear to affect the nurse's job-satisfaction. It appears that nurses feel to have a intensive job-satisfaction, having positive self leadership, a sense of purpose, and constructive thought. Thus, we need to steadily study self leadership, self control, and internal motivation as a new paradigm focused on self-control and internal motivation for their self-developments and advancement of nurses' organizations.

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.