이온 공간 전하에 의한 Mylar 박막의 열자격 전류 극대치의 온도 위치 변화

황정남,김현정 연세대학교 교육대학원 1984 연세교육과학 Vol.25 No.-

Thermally stimulated current curves from ion injected mylar film using liquid contact charging method show two peaks at about 350 K (peak A) and 380 K (peak B). Peak A is found to be due to ionic spice charge polarization. Activation energy and escape frequency for peak B is found to be (2.54±0.21) eV and (4.17±0.16)×1032 sec-1, respectively. And TSC intensities are increased with increasing the concentration of ions, while TSC peak temperature are decreased. These results are in good agreement with theoretical values.

Folie a Deux : FOLIE A DEUX IN FRATERNAL TWINS

이정균,이기황,남명석 大韓神經精神醫學會 1968 신경정신의학 Vol.7 No.1

The authors analyzed dynamically and discussed a case of folie a deux manifested as paranoid schizophrenic reaction in fraternal twins. The lives of the twins are just like that of a person. They have never seperated through their lives. They had lain in the mother's womb together, slept under a coverlet, sat side by side in the school and always went around everywhere in pairs. They have hardly had any intimate friends or neighbors, and even when they had a friend, he was not the friend of a twin but of both. It appears that they formed a microsociety, in which close association and free activity occurred sharing their thinkings, feelings, interests, apprehensions and hopes. Through such a life it is expected that they could not grow up independent personalities an their egos could not be differentiated to each individual. And it is probable that the two undifferentiated egos become a whole one and gain safety and satisfaction by their union. It will be very natural that the thought of one partner is transferred to the other through the symbiosis of personality. Most authors emphasize the dominant-submissive relationship between the primary patient and the secondary partner, but we think it is not inevitable in folie a deux. The long intimate association of partners isolated from the society will promote to form the morbid personality structure that is the soil in which delusions may be sown and flourish.

Li^+이온이 주입된 D_2O 얼음의 열자극 발광 현상에 관한 연구

박영우,황정남,이철주 연세대학교 자연과학연구소 1987 學術論文集 Vol.19 No.-

저온에서 편극시킨 탈이온수 얼음의 열자극 편극 소거 전류(Thermally Stimulated Depolarization Current ; TSDC)를 77K∼250K 범위에서 측정하여 Li^+ 이온이 주입된 D_2O 얼음의 이온공간전하 열자극 전류(Ionic Space Charge Thermocurrent ; ITC)와 열자극 발광(Thermoluminescence ; TL)을 측정하였다. D_2O 얼음의 TSDC인 경우는 173K에서 heterocharge가 나오고 200K에서 homocharge가 나온다. 이 때 heterocharge는 1차 kinetic임을 알았고, initial rise법으로 구한 활성화에너지는 0.16eV이다. D_2O 얼음의 heterocharge는 bulk에 의한 효과이고, homocharge는 공간전하에 의한 TSDC임을 확인하기 위하여, 가속기를 이용해 Li^+이온을 주입시킨 D_2O 얼음의 TL을 조사해본 결과 114K(A-peak), 180K(C-peak)에서 3개의 TL peak가 형성되는데 각각의 활성화에너지는 0.03eV, 0.15eV 및 0.29eV이다. 이중에 B-peak의 활성화에너지 값과 거의 일치하여 그 결과로 부터 B-peak의 근원이 이온공간전하에 의한 쌍극자 재정렬임을 최초로 확인하였다. Thermally stimulated depolarization current(TSDC) has been measured in distilled and deionized water ice in the temperature range of 77∼250K at a constant heating rate, and the ionic space charge thermocurrent(ITC) and thermoluminescence(TL) has been measured from Li^+ion implanted D_2O ice. In the case of TSDC of D_2O ice, the heterocharge give rise to 173K, while the homocharge give rise to 200K TSDC peak. The heterocharge peak TSDC is found to be 1st kinetic and that the activation energy is o.16eV using the initial rise method. In order to investigate that the heterocharge is due to the polarization in the D_2O ice and the homocharge due to the ionic space charge, TL curve from Li^+ion implanted D_2O ice and the homocharge due to the ionic space charge, TL curve from Li^+ion implanted D_2O ice shows three peaks at 114K, 148K and 183K. The activation energy for these TL peaks are 0.03eV, 0.15eV and 0.29eV, respectively. The activation energy for B-peak(0.16eV) is coincide with that of ITC peak which means that both TL peak and ITC peak are caused by the dipole reorientation due to ionic space charge. This approach to clarifies for the first time to my knowledge.

이온주입이 금속의 일함수에 미치는 영향(Ⅰ)

김현경,강석태,황정남,이철주,최대선,정병두 연세대학교 자연과학연구소 1984 學術論文集 Vol.13 No.-

이온 주입이 일함수 차이에 미치는 영향을 연구하기 위하여 낮은 에너지 이온 가속기, 전자총과 기타 일함수 차이를 측정하기 위한 장치를 설계, 제작하였다. 제작된 이온 가속기의 집속 특성은 이론적인 값과 일치하였다. 즉, 집속 렌즈의 확대율이 이론값은 2.0인데 비하여 1.2로 상당히 작은 값이었다. 또한 집속 렌즈의 전압 V_L과 추출 전압 V_e에 의한 집속 특성 역시 이론값과 매우 잘 일치하였다 . 제작된 장치를 사용하여 다결정 Cu와 Ni의 일함수 차이를 측정한 결과 0.45eV임을 알았다. 그리고 전자선을 이용하여 억제 전위차로 일함수를 측정할때 입사 전자의 반사율을 고려해야 함을 알았다. Low energy ion accelerator, electron gun, and apparatus for measuring work function difference are designed and constructed in order to study the effect of ion implantation on the work function. The focusing properties of accelerator is coincided with theoretical results; the magnification of Einzel lens is found to be 1.2, while theoretical value is 2.0, and the focal properties as a function of V_L/V_e are in good agreement with theory. Using these systems, the work function difference between polycrystalline Cu and Ni is found to be 0.45eV, and the experimental retarding potential plots indicate close agreement with the theoretical values modified by electron reflection.

Glow放電法에 의한 α-Si蒸着裝置의 製作과 그 試料의 特性

유동선,현옥배,고년규,황정남,정원모,이철주 연세대학교 자연과학연구소 1981 學術論文集 Vol.7 No.-

Glow방전법에 의해서 SiH_4를 분해하여 α-Si 박막을 얻을수 있는 장치를 제작하였다. 이 SiH_4기체는 수소기체속에서 10%로 희석되였으며, 진공방전함속에서 rf 전압에 의하여 분해된 Si는 유리기판위에 증착된다. α-Si박막은 1~1.6 A˚/sec의 증착율로 약 7000 A˚의 두께까지 증착되였다. α-Si 박막의 흡수계수는, 2.3 eV의 photon energy 영역에서 약 10^4 cm^-1이고, 그 optical gap은 약 2.1 eV였다. 이 박막의 증착율은 전극간격에 따라 변하고 있으나, 최적전극간격과 기체유입량은 각각 2.6cm와 1~2cc/min였다. Apparatus capable of producing α-Si film by the glow discharge method was designed and constructed in this study. The monosilane gas which is diluted in H_2 gas to 10% is decomposed in the reaction chamber by rf oscillation. The apparatus is composed of a reaction chamber, a rf generator, a cooling system, etc. The α-Si thin film is produced at a deposition rate of 1~1.6 A˚/sec to a thickness of about 7000 A˚. Its absorption coefficient is about 10^4 cm^-1 in the photon energy region of ~2.3 eV, and its optical gap is about 2.1 eV. The deposition rate for the film is controlled by varying the distance between electrode and substrate. The optimum distance and gas flow is about 2.6 cm and 1~2 cc/min, respectively.

이온 주입이 금속의 일함수에 미치는 영향(Ⅱ)

백영환,김현경,강석태,황정남,이철주,최대선,정병두 연세대학교 자연과학연구소 1985 學術論文集 Vol.15 No.-

낮은 에너지 가속기를 제작하여 순도가 99.99%인 다결정 Ni에 Li^+ 이온을 7 keV의 에너지로 각 시료에 대한 이온주입율이 1.3×10^16atoms/㎠, 4.0×10^15atoms/㎠, 2.0×10^15atoms/㎠, 1.0×10^15atoms/㎠, 2.0×10^14atoms/㎠ 가 되도록 주입시킨 후 전자총과 억제 전위차형 에너지 분석기를 이용하여 일함수의 변화를 측정하였다. 이온 주입율이 2×10^15atoms/㎠보다 작을 때는 일함수가 1.9 eV까지 감소하였고 이온주입율이 4.0×10^15atoms/㎠보다 많을 때는 일함수가 2.8 eV까지 증가하였다. 이것은 Topping의 이론 및 Bauer의 실험결과와 일치함을 보였다. The changes in the work function of polycrystalline Ni with a purity of 99.99% due to Li^+ ions implanted using a low energy ion accelerator and retarding potential energy analyser(RPEA) have been studied. The implantation energy of the Li^+ ions is 7 keV and the implanted ion dose for the various samples are 1.3×10^16 atoms/㎠, 4.0×10^15 atoms/㎠, 2.0×10^15 atoms/㎠, 1.0×10^15 atoms/㎠ and 2.0×10^14 atoms/㎠. When the ion dose is less than 2×10^15 atoms/㎠ the, work function decreases to 1.9 eV, but when the ion dose is more than 4×10^15 atoms/㎠, the work function increses to 2.8 eV. These results are in good agreement with Topping's theory and Bauer's experiment.

非晶質 Silicon 薄膜의 製作 및 그 Doping 效果

최범식,김수길,고년규,황정남,정원모,이철주 연세대학교 자연과학연구소 1982 學術論文集 Vol.9 No.-

SiH_4 기체에 PH_3 및 B_2H_6 기체를 0.7% 체적비로 혼합하여 rf glow 방전법으로 n형 및 p형 a-Si:H 박막을 기판온도 120℃에서 제작하여, 광투과도 측정, 열처리에 따른 전기 전도도의 변화 등을 조사하여 이들의 doping 효과를 연구하였다. n형, p형 및 undoped a-Si:H 박막의 optical gap은 각각 1.73eV, 1.86eV 및 1.86eV로 doping이 많이 이루어질수록 줄어 들었다. 250℃에서 열처리한 시료들의 상온에서의 전도도는 각각 2×10^-2Ω^-1㎝^-1, 5×10^-8Ω^-1㎝^-1, 5×10^-7Ω^-1㎝^-1이었고, 활성화 에너지 ??E는 각각 0.16eV, 0.49eV 및 0.48eV이었다. 300℃에서 열처리한 결과, ??E는 줄어 들고 전도도는 증가하였다. 350℃ 및 450℃에서 열처리한 결과 dehydrogenation 효과로 인하여 n형과 p형은 서로 상반되는 결과를 보였다. 즉, n형 시료의 전도도는 감소하고 ??E는 증가하였지만, P형 시료의 전도도는 증가하고 ??E는 감소하였다. 저온 영역에서 구한 n형 시료의 전도도로부터 hopping 활성화 에너지를 구한 결과 0.085eV이었다. Thin n-type and p-type a-Si:H films were prepared by rf glow discharge decomposition of silane mixed with 7×10^-3 parts per volume of phospine or diborane. All specimens were deposited on glass substrates held at 120℃. In order to determine the doping effects the opital absorption and dc conductivity of these specimens were measured after annealing at various temperatures. The optical gap was 1.73eV in the case of the n-type specimens, 1.80eV for the p-type, and 1.86eV undoped. This showed that the gap width decreased as the doping increased. The room temperatuer conductivities of these specimens annealed at 250℃ were 2×10^-2Ω^-1㎝^-1, 5×10^-8Ω^-1㎝^-1, and 5×10^-7Ω^-1㎝^-1, respectively, and the activation energies, ??E, of these specimens were 0.16eV, 0.49eV, and 0.48eV, respectively. For specimens annealed at 300℃, ??E decreased and the conductivity increased. When these specimens were annealed at 350℃ and 450℃, dehydrogenation caused opposite effects on the n-type and p-type specimens; the conductivities of n-type specimens decreased and ??E increased, but the conductivities of p-type specimens increased and ??E decreased.From an investigation of the temperature dependence of the conductivity of the n-type specimen in the low temperature region, we determined that the hopping activation energy was 0.085eV.

전자선 증착장치 및 ITO 박막의 제작과 그 특성에 관한 연구

김수길,최범식,우정주,고년규,황정남,정원모,이철주 연세대학교 자연과학연구소 1982 學術論文集 Vol.9 No.-

태양 전지의 제작시 투명 전극막으로 쓰이는 ITO 박막을 제조하기 위하여 cathode 접지 방식의 전자총을 가진 정전 편향 집속형의 전자선 증착 장치를 제작하였다. 가속전압이 0∼15kV, 필라멘트 전류가 0∼28A, 두 전극판 사이의 간격이 11mm, anode와 deflector 사이의 간격이 30mm인 최적 실험조건하에서 생성된 전자선 spot의 크기는 길이가 20mm 폭이 1mm였으며, 전자선의 출력은 약 400W였다. 이 전자선 증착 장치를 이용하여 1600℃까지의 증발 온도를 가진 도체와 절연체 등을 쉽게 증착시킬 수 있었으며, 만드어진 ITO 박막은 약 5000Å의 두께에서 10^-1∼10^-2Ω·㎝의 비저항과 95%의 광투과율을 갖는다. An electron beam evaporator with a cathode grounded type electron gun was designed and constructed in order to deposit ITO thin films for photovoltaic applications. The optimum condition was observed with electode spacing of 11mm, 30mm between anode and deflector, a cathode inner diameter of 3mm and an anode inner diameter of 5mm. As the accelerating voltage varies from 0 to 15kV and ghe filament current from 0 to 28 A, the minimum electron beam spot has a 20mm length, and 1mm width and the output power ranges from 0 to 400W under the above optimum conditions. We can deposit materials whose evaporation temperature is over 1600℃ using this evaporator. And as a result ITO thin film showed a low resistivity of 10^-1∼10^-2Ω·㎝ and the transmittance of 95%.

Lymphoepithelial cysts in the pancreas: MRI of two cases with emphasis of diffusion-weighted imaging characteristics

Nam, Se Jin,Hwang, Ho Kyoung,Kim, Hyunki,Yu, Jeong-Sik,Yoon, Dong-Sup,Chung, Jae-Joon,Kim, Joo Hee,Kim, Ki Whang Wiley Subscription Services, Inc., A Wiley Company 2010 JOURNAL OF MAGNETIC RESONANCE IMAGING Vol.32 No.3

<P>Pancreatic lymphoepithelial cysts (LECs) are rare pancreatic cystic lesions filled with keratinized material, lined by mature, keratinizing squamous epithelium and surrounded by lymphoid tissue containing few lymphoid follicles. We report two cases of surgically confirmed pancreatic LECs showing a profound restriction of water molecules on diffusion-weighted (DWI) magnetic resonance imaging (MRI). For pancreatic cystic lesions showing lack of molecular motion on DWI with or without thin marginal enhancement on contrast material-enhanced imaging, LECs consisting of internally keratinized materials with restricted diffusion should be considered in differential diagnoses even though they cannot always be easy to distinguish from other focal pancreatic lesions containing mucin, blood clot, or nonliquefactive necrosis. J. Magn. Reson. Imaging 2010;32:692–696. © 2010 Wiley-Liss, Inc.</P>

Editorial on the launch of Current Applied Physics

Elsevier 2001 CURRENT APPLIED PHYSICS Vol.1 No.1