Thermoluminescent Response of Thin LiF:Mg,Cu,Na,Si Detectors to Beta Radiation

Cho,H.W.,Chang,S.Y.,Nam,Y.M.,Kim,J.L.,Kim,H.J. 대한방사선 방어학회 1999 방사선방어학회지 Vol.24 No.1

최근 개발된 감도가 좋은 LiF:Mg,Cu,Na,Si TL물질을 Teflon과 혼합한 후, 얇은 디스크 형태로 압축·성형한 얇은 LiF:Mg,Cu,Na,Si Teflon 검출기를 제작하고 베타선 검출기로서의 TL 반응특성을 연구하였다. 한국원자력연구소의 Pm, Tl 및 Sr/Y 베타선원을 이용하여 두께 2 ㎎/㎠인 kapton 박막을 덮은 상태로 베타선을 조사하였다. 제작한 얇은 LiF:Mg,Cu,Na,Si 검출기들의 Cs에 대한 batch 균질성은 4.7%, 베타선에 대한 선량의존성은 0.1 m㏉에서 100 ㏉까지 선형성을 나타내고, 에너지의존성은 Pm, Tl 및 Sr/Y 베타선에 대해 각각 0.46, 1.09 및 1.06 이었다. 그리고 베타선에 대한 방향의존성은 0.93±0.03 (Pm), 0.94±0.04 (Tl) 및 0.92±0.05 (Sr/Y)으로, 이들 얇은 LiF:Mg,Cu,Na,Si 검출기들에 대한 Tl 반응특성의 결과는 국제표준기구(ISO)의 베타선량계 기준을 잘 만족하였다. Thermoluminescent (TL) response characteristics of a thin LiF:Mg,Cu,Na,Si Teflon detectors have been studied for use in beta radiation detection. The detectors were fabricated from a mixture of LiF:Mg,Cu,Na,Siphosphor and Teflon powder which was molded into a thin disk form of 50 ㎎/㎠ These detectors were irradiated to beta fields of Pm, Tl and Sr/Y sources with a covering of Kapton foil (2 ㎎/㎠) and photon irradiation was carried out with a Cs source at the Korea Atomic Energy Research Institute (KAERI). Batch uniformity was estimated to be 4.7% and the beta dose response presented linear relationship from 0.1 m㏉ to 100 ㏉. The beta energy responses of thin detectors normalized to Cs were presented as 0.46, 1.09 and 1.06 for Pm, Tl and Sr/Y beta rays, respectively. The evaluated values for angular responses were 0.93±0.03 (Pm), 0.94±0.04 (Tl), and 0.92±0.05 (Sr/Y). The results satisfied well a proposed ISO Standard for beta ray dosimeters.

Random Stability of an Additive-Quadratic-Quartic Functional Equation

Mohamadi, M.,Cho, Y. J.,Park, C.,Vetro, P.,Saadati, R. Hindawi Publishing Corporation 2010 Journal of inequalities and applications Vol.2010 No.1

<P>Using the fixed point method, we prove the generalized Hyers-Ulam stability of the following additive-quadratic-quartic functional equation f(x+2y)+f(x-2y)=2f(x+y)+2f(-x-y)+2f(x-y)+2f(y-x)-4f(-x)-2f(x)+f(2y)+f(-2y)-4f(y)-4f(-y) in complete random normed spaces.</P>

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.

다운증후군의 산전진단을 위한 다양한 선별검사의 기여율 비교 - 산전 및 신생아때 진단된 96 례 분석 -

한정열(J . Y . Han),김문영(Y. M . Kim),조준형(J . H . Cho),안현경(H . K . Ahn),류현미(H . M . Ryu),김진미(J . M . Kim),김영미(Y . M . Kim),박소연(S . Y . Park),한혜경(H . K . Han),이영호(Y . H . Lee),양재혁(J . H . Yang) 대한산부인과학회 2000 Obstetrics & Gynecology Science Vol.43 No.10

Objective : The purpose of this study was comparison of the contribution rate for prenatal diagnosis of Down syndrome using various screening methods (Age: greater than or equal to 35 years old, Serum markers: Triple test, Ultrasonography: abnormal sonographic findings, nuchal translucency, nuchal fold thickness).Methods : Total 96 cases of Down syndrome, prenatally or postnatally diagnosed between Jan. 1990 and Sept. 1999, made up the study population. We got the contribution rate of various prenatal screening methods of down syndrome, and obtained the efficiency of various screening program applied for last 10 years. Results : The frequencies of Down syndrome confirmed in prenatal and postnatal were 68 (71%) and 28 (29%) in respectively. The mean age of mother of Down syndrome fetus was 33.0±5.7 years old. The frequency rate of Down syndrome was 0.4, 1.3, 0.7, 0.7, 1.6, 0.7, 1.2, 2.2, 2.0 and 2.3 a 1,000 deliveries from 1990 to 1999 (Y= 0.28+0.18 year, P=0.01). The percentage of Down syndrome diagnosed prenatally was 0 (0/2), 43 (3/7), 50 (2/4), 25 (1/4), 56 (5/9), 100 (5/5), 71 (5/7), 78 (14/18), 78 (14/18) and 89 (17/19) from 1990 to 1999 (Y= 12.9+8.9 year, P=0.000). The contribution rate of prenatal diagnosis for Down syndrome was 30.2±5.6% by age, 18.2±3.4% by triple test and 51.7±6.3% by ultrasonography, and was significantly difference among each screen methods (P=0.008). Conclusions : This study shows that our prenatal screening program is highly effective to detect Down syndrome and especially ultrasonographic findings (abnormal sono findings, Nuchal translucency, Nuchal fold thickness) may be more important than that of age or Triple test to detect the Down syndrome prenatally.

Evolution of carbides in cold-work tool steels

Kim, H.,Kang, J.Y.,Son, D.,Lee, T.H.,Cho, K.M. Elsevier 2015 Materials characterization Vol.107 No.-

This study aimed to present the complete history of carbide evolution in a cold-work tool steel along its full processing route for fabrication and application. A sequence of processes from cast to final hardening heat treatment was conducted on an 8% Cr-steel to reproduce a typical commercial processing route in a small scale. The carbides found at each process step were then identified by electron diffraction with energy dispersive spectroscopy in a scanning or transmission electron microscope. After solidification, MC, M<SUB>7</SUB>C<SUB>3</SUB> and M<SUB>2</SUB>C carbides were identified and the last one dissolved during hot compression at 1180<SUP>o</SUP>C. In a subsequent annealing at 870<SUP>o</SUP>C followed by slow cooling, M<SUB>6</SUB>C and M<SUB>23</SUB>C<SUB>6</SUB> were added, while they were dissolved in the following austenitization at 1030<SUP>o</SUP>C. After the final tempering at 520<SUP>o</SUP>C, fine M<SUB>23</SUB>C<SUB>6</SUB> precipitated again, thus the final microstructure was the tempered martensite with MC, M<SUB>7</SUB>C<SUB>3</SUB> and M<SUB>23</SUB>C<SUB>6</SUB> carbide. The transient M<SUB>2</SUB>C and M<SUB>6</SUB>C originated from the segregation of Mo and finally disappeared due to attenuated segregation and the consequent thermodynamic instability.

Supplementation of oil-based inactivated H9N2 vaccine with M2e antigen enhances resistance against heterologous H9N2 avian influenza virus infection

Park, J.K.,Lee, D.H.,Cho, C.H.,Yuk, S.S.,To, E.O.,Kwon, J.H.,Noh, J.Y.,Kim, B.Y.,Choi, S.W.,Shim, B.S.,Song, M.K.,Lee, J.B.,Park, S.Y.,Choi, I.S.,Song, C.S. Elsevier Scientific Pub. Co 2014 Veterinary microbiology Vol.169 No.3

Avian influenza virus (AIV) subtype H9N2 has been evolving rapidly and vaccine escape variants have been reported to cause circulation of infections and economic losses. In the present study, we developed and evaluated ectodomain of the AIV matrix 2 (M2e) protein as a supplementing antigen for oil-based inactivated H9N2 vaccine to increase resistance against vaccine escape variants. AIV H9N2 M2e antigen was expressed in Escherichia coli and supplemented to inactivated H9N2 oil emulsion vaccine. Specific pathogen-free chickens received a single injection of inactivated H9N2 oil emulsion vaccines with or without M2e supplementation. At three weeks post vaccination, hemagglutination inhibition tests and enzyme-linked immunosorbent assays were performed to determine serological immune responses. Challenge study using a vaccine escape H9N2 variant was performed to evaluate the efficacy of M2e supplementation. M2e antigen supplemented in oil emulsion vaccine was highly immunogenic, and a single M2e-supplemented vaccination reduced challenge virus replication and shedding more effectively than non-supplemented vaccination.

Cyclobuxine D의 토끼 적출 장관에 대한 작용

이종화,박영현,조병헌,김종배,김정목,김유재,김천숙,차영덕,김영석 최신의학사 1988 最新醫學 Vol.31 No.1

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>

200 GeV/핵자 유황이온과 핵건판핵의 충돌에 의해 생성된 헬륨 파쇄핵의 극한파쇄 연구

김동철,송진섭,윤천실,정성헌,박인곤,김종오,김철수,김태연,이승희,조재희,천병구,김재률,김준원,김태익,박명렬,장한일,임인택 慶尙大學校 기초과학연구소 1992 基礎科學硏究所報 Vol.8 No.-

고에너지 중이온 원자핵과 핵건판의 충돌에서, 200GeV/핵자 유황이온에 의해 생성된 파쇄 헬륨핵(Z=2)의 실험실계의 방출각 분포는 표적핵에 무관한 회귀공식. dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)]로 잘 표현된다. 여기에서 의사신속도 η=-ln[tan(θ/2)]이고, y_b는 실험실계의 입사입자(^32S)의 신속도이다. 이 공식에 의한 적합에서 k=-0.057±0.008로 얻어진다. 즉, 핵건판과 고에너지 중이온의 충돌에서 파쇄 헬륨핵의 exp(η-y_b)의 분포는 "극한파쇄" 현상을 잘 설명하고 있다. The angular distribution of emission angle θ of helium (Z=2) produced in the collisions of incident particles of 200 GeV/nucleon ^32S in nuclear emulsion is well expressed by dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)] where the pseudorapidity is η=-ln[tan(θ/2)], the laboratory system primary rapidity is y_b, and k=-0.057+0.008. The shape of this frequency of occurrence distributions in terms of exp(η-y_b) attests to the validity of the concept of "limiting fragmentation" for helium projectile fragments produced in the projectile fragmentation regions of heavy ion collisions in nuclear emulsion.

세관 양광주 방전에서 플라즈마 확산의 완전 해

김동준,정종문,김정현,황하청,정재윤,조윤희,임현교,구제환,최은하,조광섭,Jin, D.J.,Jeong, J.M.,Kim, J.H.,Hwang, H.C.,Chung, J.Y.,Cho, Y.H.,Lim, H.K.,Koo, J.H.,Choi, E.H.,Cho, G.S. 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.1

관경이 수 mm인 세관 램프 내부에서 플라즈마의 확산을 조사하기 위하여 이극성(ambipolar) 확산방정식을 해하였다. 반경 방향의 확산에 의한 유리관 벽에서의 플라즈마 소멸 특성시간은 $\tau_r\;=\;(r_0/2.4)^2/D_a$로 주어진다. 반경 $r_0{\sim}1\;mm$이고 이극성 확산계수 $D_a{\sim}0.01\;m^2/s$ 이면, $\tau_r{\sim}17\;{\mu}s$이다. 이는 램프의 교류전원 구동에서 플라즈마를 유지하기 위한 구동 최소 주파수 ~30 kHz에 해당한다. 고전압이 인가되는 전극부에 발생한 고밀도의 플라즈마가 양광주로 확산되는 특성시간은 $\tau_z{\sim}0.1\;s$이다. 고밀도 플라즈마 경계에서의 시간에 대한 확산속도는 $t{\sim}10^{-6}\;s$일 때 $u_D{\sim}10^2\;m/s$이고, $t{\sim}10^{-3}\;s$이면 그 속도는 $u_D{\sim}1\;m/s$로 느려진다. 따라서 램프 길이 ~1 m에 대하여 전극부에서 생성된 고밀도 플라즈마가 양광주 전체로 확산되는 시간은 수 초가 걸린다. The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.