DMF effect on the morphology and the luminescence properties of Y₂O₃:Eu³⁺ red phosphor prepared by spray pyrolysis

Jung, K.Y.,Kang, Y.C.,Park, Y.K. Korean Society of Industrial and Engineering Chemi 2008 Journal of industrial and engineering chemistry Vol.14 No.2

N,N-Dimethylformamide (DMF) was used as a drying control chemical additive (DCCA) in spray pyrolysis in order to improve the luminous properties of Y<SUB>2</SUB>O<SUB>3</SUB>:Eu particles. It was found that the addition of DMF to the spray solution containing citric acid (CA) and ethylene glycol (EG) greatly enhances the photoluminescence intensity as well as the morphology of Y<SUB>2</SUB>O<SUB>3</SUB>:Eu particles. According to BET analysis, the surface area of Y<SUB>2</SUB>O<SUB>3</SUB>:Eu particles prepared from the solution containing only the organic additives was not reduced, whereas, the surface area of the Y<SUB>2</SUB>O<SUB>3</SUB>:Eu particles prepared from the solution containing both DMF and organic additives was decreased gradually as increasing the concentration of DMF. From these results, it was concluded that the adding of DMF to the spray solution containing the organic additives is a very effective way to reduce the porosity of phosphor particles, keeping the spherical morphology. As a result, the densification of porous structure led to greatly improve the photoluminescence intensity of Y<SUB>2</SUB>O<SUB>3</SUB>:Eu particles under ultraviolet (254nm) excitation. Finally, the prepared Y<SUB>2</SUB>O<SUB>3</SUB>:Eu particles with dense structure showed about 208% improved photoluminescence intensity compared with the particles which have a spherical shape but porous structure.

열처리에 따른 Y₂O₃박막의 미세 구조 변화와 전기적 특성 변화에 대한 고찰

정윤하(Y. H. Jung),강성관(S. K. Kang),김은하(E. H. Kim),고대홍(D. H. Ko),조만호(M. H. Cho),황정남(C. N. Whang) 한국진공학회(ASCT) 1999 Applied Science and Convergence Technology Vol.8 No.3(1)

p-type Si (100) 기판 위에 습식 산화법으로 SiO₂ 층을 형성한 후, Ionized Cluster Beam(ICB) 증착 방법으로 200 Å 두께의 Y₂O₃ 박막을 증착 하였다. Y₂O₃ 박막이 증착 된 시편을 산소, 아르곤 분위기에서 열처리한 후, Atomic Force Microscopy(AFM)과 Transmission Electron Microscopy(TEM)을 사용하여 Y₂O₃ 박막의 표면과 계면을 관찰하였다. 열처리를 수행한 후 Y₂O₃ 박막과 Si 기판 사이에서 SiO₂층이 성장하고, 이트륨실리 케이트 층이 형성되는 것을 관찰할 수 있었다. 산소 분위기에서 열처리를 수행한 시편의 Y₂O₃ 박막 표면을 관찰한 결과, 표면 상부에 아르곤 분위기에서 열처리한 시편에서는 보이지 않았던 새로운 상이 형성되었음을 알 수 있었다. 또한 전기적 특성을 측정하기 위하여 Al/Y₂O₃/p-type Si (100) 의 캐패시턴스-전압 특성을 관찰하였고, 그 결과 Y₂O₃ 박막의 유전 상수 값이 약 9정도임을 알 수 있었다. We investigated the interfacial reactions between the Y₂O₃ film deposited by ICB processing and p-type (100) Si substrates upon annealing treatments in O₂ and Ar gas ambients. We also investigated the evolution of surface morphology of ICB deposited Y₂O₃ films upon annealing treatments. We observed that the root-mean-square (RMS) value of surface roughness measured by AFM increased with annealing time at 800℃ in O₂ ambient, while the change of surface roughness was not observed in Ar ambient. We also found the growth of SiO₂ layer and the formation of yttrium silicate layer. From the capacitance values (C_(acc)) measured by C-V measurements, the relative dielectric constant of Y₂O₃ film in metal-insulator-semiconductor (MIS) structure was estimated to be about 9.

Comparison of 90‐day case‐fatality after ischemic stroke between two different stroke outcome registries using propensity score matching analysis

Yu, K‐,H.,Hong, K‐,S.,Lee, B‐,C.,Oh, M‐,S.,Cho, Y‐,J.,Koo, J‐,S.,Park, J‐,M.,Bae, H‐,J.,Han, M‐,K.,Ju, Y‐,S.,Kang, D‐,W.,Appelros, P. Blackwell Publishing Ltd 2011 Acta neurologica Scandinavica Vol.123 No.5

<P>Yu K‐H, Hong K‐S, Lee B‐C, Oh M‐S, Cho Y‐J, Koo J‐S, Park J‐M, Bae H‐J, Han M‐K, Ju Y‐S, Kang D‐W, Appelros P, Norrving B, Terent A. Comparison of 90‐day case‐fatality after ischemic stroke between two different stroke outcome registries using propensity score matching analysis. 
Acta Neurol Scand: 2011: 123: 325–331. 
© 2010 John Wiley & Sons A/S.</P><P><B>Background – </B> It has not been clarified whether the disparity in ischemic stroke outcome between populations is caused by ethnic and geographic differences or by variations in case mix. Propensity score matching (PSM) analysis can overcome some analytical problems but is rarely used in stroke outcome research. This study was to compare the ischemic stroke case‐fatality between two PSM cohorts of Sweden and Korea.</P><P><B>Methods – </B> Prognostic variables related to baseline characteristics and stroke care were included in our PSM model. Then, we selected 7675 Swedish and 1220 Korean patients with ischemic stroke from each stroke registers and performed one‐to‐one matching based on propensity scores of each patient.</P><P><B>Results – </B> After PSM, all measured variables were well balanced in 1163 matched subjects, and the 90‐day case‐fatality was identical 6.2% (HR 0.997, 95%CI 0.905–1.099) in Sweden and Korea.</P><P><B>Conclusions – </B> No difference is found in the 90‐day case‐fatality in propensity score‐matched Swedish and Korean patients with ischemic stroke.</P>

Novel effects of FTY720 on perinuclear reorganization of keratin network induced by sphingosylphosphorylcholine: Involvement of protein phosphatase 2A and G-protein-coupled receptor-12

Park, M.K.,Park, S.,Kim, H.J.,Kim, E.J.,Kim, S.Y.,Kang, G.J.,Byun, H.J.,Kim, S.H.,Lee, H.,Lee, C.H. North-Holland ; Elsevier Science Ltd 2016 european journal of pharmacology Vol.775 No.-

<P>Sphingosylphosphorylcholine (SPC) evokes perinuclear reorganization of keratin 8 (K8) filaments and regulates the viscoelasticity of metastatic cancer cells leading to enhanced migration. Few studies have addressed the compounds modulating the viscoelasticity of metastatic cancer cells. We studied the effects of sphingosine (SPH), sphingosine 1-phosphate (S1P), FTY720 and FTY720-phosphate (FTY720P) on SPC-induced K8 phosphorylation and reorganization using Western blot and confocal microscopy, and also evaluated the elasticity of PANC-1 cells by atomic force microscopy. FTY720, FTY720P, SPH, and SIP concentration-dependently inhibited SPC-evoked phosphorylation and reorganization of K8, and migration of PANC-1 cells. SPC triggered reduction and narrow distribution of elastic constant K and conversely, FTY720 blocked them. A common upstream regulator of JNK and ERK, protein phosphatase 2A (PP2A) expression was reduced by SPC, but was restored by FTY720 and FTY72P. Butyryl forskolin, a PP2A activator, suppressed SPC-induced K8 phosphorylation and okadaic acid, a PP2A inhibitor, induced K8 phosphorylation. Gene silencing of PP2A also led to K8 phosphorylation, reorganization and migration. We also investigated the involvement of GPR12, a high-affinity SPC receptor, in SPC-evoked keratin phosphorylation and reorganization. GPR12 siRNA suppressed the SPC-triggered phosphorylation and reorganization of K8. GPR12 overexpression stimulated keratin phosphorylation and reorganization even without SPC. FTY720 and FTY720P suppressed the GPR12-induced phosphorylation and reorganization of K8. The collective data indicates that FTY720 and FTY720P suppress SPC-induced phosphorylation and reorganization of K8 in PANC-1 cells by restoring the expression of PP2A via GPR12. These findings might be helpful in the development of compounds that modulate the viscoelasticity of metastatic cancer cells and various SPC actions. (C) 2016 Elsevier B.V. All rights reserved.</P>

한국인 Long Term Non Progressors로부터 분리된 HIV-1 env 및 nef 유전자와 이들의 면역 유전학적 특성 분석에 의한 질병진전 요인 규명

이주실,강춘,김성순,박근용,고운영,기미경,최병선,남정구,서순덕,이성래,구본기,박혜경,도경미,김태규,최희백,조현일,김요숙,김지영,이해정,안수진 국립보건연구원 1999 국립보건원보 Vol.36 No.-

1987년 한국에서 발생한 렙토스피라병의 혈청역학적 조사

이증훈,박영수,이우곤,김석용,정선식,우준희,박성광,박경희,송영욱,김선영,기정일,최두혁,강성귀,김주완,최강원,김우열,최명식,최인학,장우현,윤성열 대한감염학회 1988 감염 Vol.20 No.3

Human leptospirosis was an unfamiliar disease in Korea until 1984 that outbreak of leptospirosis occurred among farmers and soldiers after field works for harvesting rice. During that time, Lee and Jo confirmed the first Korean cases of leptospirosis by serological test, isolation of causative agent and autopy findings. Afterward several outbreaks occurred also during autumn especially after flood in every years and some characterisitcs of leptospirosis in Korea such as clinical manifestations, serotypes and seroepidemiological features has been revealed by many investigators. Because of the major mode of transmission between rodents and human is by direct contact with leptospiral urine of rodents or contaminated soil by the urine, leptospirosis in Korea has been primarily a disease of person in occupations heavily exposed to contaminated soil or infected urine such as farmer, army and etc. Therefore it seems that leptospirosis is one of the main communicable diseases to be controlled urgently in Korea, for an agricultural people account for almost half of total Korean people. For clarifying the seroepidemiological patterns of human leptospirosis in Korea by sex, month region and main reacting serovars of L. interrogans among acute febrile disease occurred in 1987, 1,773 patient's sers with acute febrile episodes were tested by microagglutination test using 19 representative strains of leptospiral serogroup as antigen. All of those sera were collected from 10 collaborative clinics located in Kyunggi, Kangwon, Chungbuk, Chungnam, Chonbuk, Chonnam province and Seoul. The results wee summerized as follows. 1) Among 1,773 sera of patients with acute febrile episodes, 219 (12.4%) were seropositive to L. interrogans, 487(27.5%) to R. tsutsugamushi, 241(13.6%) to R.typhi and 160(90.0%) to Hantaan virus. 2) Among seropositives to L.interrogans, the male outnumbered the female, 65% and 35%. 3) For age distribution, 26.9% of seropositives to L.interrogans were fifties, 19.6% were forties, 9.1% were sixties, 5.9% were thirties and 4.1% were twenties. 4) Eighty three percent of seropositives had occurred between September and October in 1987 with a peak in September. 5) Main leptospiral serovars reactive to patient's sera were Icterohaemorrhagiae(54.3%), Canicola(31.0%), CH-48(13.2%), Tarassovi(0.9%)and Cynopteri(0.5%). 6) For regional distribution, 65.8% of seropositives to L.interrogans were residents from Chonbuk, 12.3% were Chonnam, 7.3% were Chungnam, 5.5% were Kyunggi and 1.4% were Kangwon.

여자 고등학생의 성태도와 부모 양육태도가 성폭력 인식수준에 미치는 영향

강수인,김수민,김유진,김지수,박지원,신수경,이지현,장은주,정채린,진애경,차지영,이수연 이화여자대학교 간호과학대학 2019 이화간호학회지 Vol.- No.53

Purpose: The study aimed to investigate the factors influencing consciousness of sexual violence in female high school students, focusing on sexual attitude and parental attitude. ethods: Data were collected from 248 female high school students in South Korea. A structured questionnaire was used for data collection through online survey. The collected data were analyzed by descriptive statistics, t-test, ANOVA, Tukey’s test, Pearson correlation coefficient, and multiple linear regression using the SPSS 25.0 program. Results: The mean score of consciousness of sexual violence in female high school students was 43.54 out of 48. The findings indicate that the mean score of consciousness of sexual violence differed y number of years in high school and academic achievement. Among sexual attitude, parental ttitude, and consciousness of sexual violence, there were meaningful correlations between onsciousness of sexual violence and sexual attitude (r=.132, p=.038,), love-hostility (r=.172, p=.006),and autonomous-control (r=.132, p=.038). Love-hostility aspect of parental attitude (=.159, p=.049) and academic achievement (=.208, p=.001) were found to be the important influencing factors on female high school student’s consciousness of sexual violence (F=5.720, p<.001). Conclusion: The findings of the study suggest that the love-hostility aspect of parental attitude and academic achievement influence consciousness of sexual violence of female high school students. Therefore, in order to improve consciousness of sexual violence in female high school students, sex education program and parent-education program should be developed with further research.

EFFECT OF HARDNESS CHANGES AND MICROSTRUCTURAL DEGRADATION ON CREEP BEHAVIOR OF A Mod.9Cr-1Mo STEEL

K-S. PARK,H-S. CHUNG,K-J. LEE,Y-G. JUNG,C-Y. KANG T. ENDO 한국자동차공학회 2005 International journal of automotive technology Vol.6 No.1

Interrupted creep tests for investigating the structural degradation during creep were conducted for a Mod 9Cr-1Mo steel in the range of stress from 71 to 167 MPa and temperature from 873 to 923 K. The change of hardness and tempered martensitic lath width was measured in grip and gauge parts of interrupted creep specimens. The lath structure was therimally stable in static conditions. However, it was not stable during creep, and the structural change was enhanced by creep strain. The relation between the change in lath width and creep strain was described quantitatively. The change in Vickers hardness was expressed by a single valued function of creep LCR(life consumption ratio). Based on the empirical relation between strain and lath width, a model was proposed to describe the relation between change in hardness and creep LCR. The comparison of the model with the empirical relation suggests that about 65% of hardness loss is due to the decrease of dislocation density accompanied by the movement of lath boundaries. The role of precipitates on subboundaries was discussed in connection with the abnormal subgrain growth appearing in low stress regime.

Development of a systematic, self-consistent algorithm for the K-DEMO steady-state operation scenario

Kang, J.S.,Park, J.M.,Jung, L.,Kim, S.K.,Wang, J.,Lee, C.Y.,Na, D. H.,Im, K.,Na, Y.-S.,Hwang, Y.S. IOP 2017 Nuclear fusion. Fusion nucléaire. &n.Illiga Vol.57 No.12

<P>An optimum plasma pressure/current density profile and corresponding heating/current drive (H/CD) determination scheme is newly developed by integrating equilibrium, stability, confinement, and H/CD, self-consistently subject to maximize the fusion gain for Korean fusion demonstration reactor (K-DEMO) steady-state operation scenarios. The integrated plasma modeling package, FASTRAN/IPS, is adopted for the integrated numerical apparatus. The target pressure profile with a pedestal structure is investigated by varying its peaking, pedestal height and width as a first step. Formation of stable equilibria is evaluated by solving the Grad–Shafranov equation and checking linear MHD stability. For the case of potentially stable equilibrium, required external heating distribution is calculated by considering both power balance and external current drive alignment to reproduce the pressure profile of the stable equilibrium. Electron/ion temperature and poloidal flux evolutions are solved with the derived heating configuration to find a steady-state scenario and achieve self-consistent plasma profiles. A self-consistent target steady-state pressure and current profile parameters are proposed through designed systematic algorithm with fusion power <I>P</I> <SUB>F</SUB>  =  2070 MW, fusion gain <I>Q</I>  =  19.7, and normalized beta <I>β</I> <SUB>N</SUB>  =  2.8 at toroidal field <I>B</I> <SUB>T</SUB>  =  7.4 T and plasma current <I>I</I> <SUB>P</SUB>  =  15.5 MA. Feasibility of fusion power <I>P</I> <SUB>F</SUB>  =  3000 MW operation is also explored with enhanced density and temperature limit assumption.</P>

Physiochemical Characteristics of Lactobacillus acidophilus KH-1 Isolated from the Feces of a Breast-Fed Infant

K. H. Yu,S. N. Kang,S. Y. Park 한국식품영양과학회 2005 Preventive Nutrition and Food Science Vol.10 No.4

Three lactobacillus strains, two from infant feces, and one from cow's milk, were selected among 172 isolates, from multiple sources, for further study based on the antimicrobial activities against six strains of pathogenic bacteria and identified as Lactobacillus acidophilus. The strains revealed a wide scope of spectrum against pathogenic bacteria. Viable Lactobacillus acidophilus KH-1 cell counts at pH 2.0 were slightly decreased to 1.42×10^7 CFU/mL from 4.18×10^7 CFU/mL, while remaining at 3.42×10^7 CFU/mL at pH 4.0 with the survival rate of 33.97% and 81.82%, respectively. At the concentration of 0.1% oxgall, L. acidophilus KH-1 kept growing up to 3.12×10^7 CFU/mL with a mean growth rate constant (k) of 0.25, and cell number was slightly decreased to 1.21×10^7 CFU/mL (k=0.19) with 0.3% oxgall, but remained at 7.6×10^6 CFU/mL (k=0.17) with 0.5% oxgall. L. acidophilus KH-1 had a D_(60) value of 7.14, with viable cell numbers 1.4×10^5 CFU/mL after heat treatment at 60℃ for 30 minutes. Stability of L. acidophilus KH-1 at -20℃ was significantly higher, when the strain was cultivated under the optimum growth temperature (54.41% and 54.35%) than at the temperature (13.53%).