Sol-Gel방법에 의해서 성장시킨PbTiO₃박막의 결정화와 물리적 성질

구영진,강민진,정원태,김태현,김상수 昌原大學校 基礎科學硏究所 2000 基礎科學硏究所論文集 Vol.12 No.-

Ferroelectric PbTiO3 thin films coated on SiO2/Si(100) and ITO glass substrates were prepared by sol-gel processing of metal alkoxide solutions and solvents. The use of sol-gel method for preparing various functional films makes it possible for the homogeneous distribution of elements at the molecular level, precise composition control, lower temperature synthesis, large surface coating and high optical quality. First of all, the XRD investigation shows that perovskite phase of polycrystalline PbTiO3 was formed by four times coating of the concentrated solution and by the heat treatment over 500, 600℃(O2 gas and air) and over 10, 20, 30 min. Surfaces of thin films were crack-free and uniform and the average grain size investigated by SEM was 0.25∼1.00 ㎛. Dielectric constant of PbTiO3/ITO glass thin film were 380 ∼ 5.25 in the region of 1 kHz∼ 10 MHz at room temperature(30℃), respectively. From the hysteresis loop of PbTiO3/ITO glass thin film, a remnant polarization of 0.382 μC/cm2 and a coercive filed of 23.85 kV/cm were obtained. At the frequency(5 kHz), C-V measurements of films in MFIS and MFM configurations showed well-behaved C-V characteristics and an injection type hysteresis. The capacitance of flat band(CFB) was 60 pF. The band gap energies of the thin films depend on the assumption of direct or indirect transition. Using one layer structure model, we calculated refractive index, extinction coefficient, absorption coefficient and band gap energy of thin film in the wavelength range of 300 to 800 nm. The band gap energy, refractive index and extinction coefficient at λ = 6325 Å of the PbTiO3 thin film were 3.7 eV, 1.96 and 0.1 respectively.

Cu-0.15Zr 합금의 전기 전도도에 미치는 가공도 및 시효처리의 영향

池泰求 홍익대학교 산업기술연구소 1998 産業技術 Vol.8 No.-

A study on the effect of working degree and aging on the electrical conductivity as well as the hardness of Cu-0.15Zr alloy was carried out. With increasing the working degree, the hardness of the alloy was more decreased as the temperature and the time increased. With increasing the working degree the recovery rate of the electrical conductivity of the alloy in contrast to the hardness decrease rate. Consequently, the alloy aged at 400℃ for 30 min had a good mechanical properties and excellent electrical conductivity.

급속응고 한 6061 Al 합금분말 압출재의 조직과 기계적 성질

池泰求 홍익대학교 산업기술연구소 1994 産業技術 Vol.4 No.-

Al scrap(Sashis) was melted in the 60㎾ high frequency induction furnace. The melt was rapidly solidified in the form of powder by a rotating disc atomizer. And the powder was extruded and subsquently was perfirmed the solution and aging treatment. The shape size distribution and microstructure of powder the microstructure mechanical properties of extrudate were examined. The microstructure of powder were typical rapidly solidified structure and fine intermetallic compounds were distributed homogeneously in extrudate. Sphere type and needle like intermetallic compound were distributed in the extrudata after T_6 treatment. The sphere type intermetallic compound was composed of Si Mg and needle like intermetallic compound was contained Fe. The extrudate showed higher hardness and tensile strength then that of casted materials such as 6061 6063 Al alloys.

급냉 응고법으로 제조한 Al-Pb, Al-Pb-Sn-Si-Cu 합금 분말 특성에 관한 연구

池泰求,李龍鎬 弘益大學校 科學技術硏究所 1993 科學技術硏究論文集 Vol.3 No.-

For development of Al-Pb alloys, a centrifugal atomizing technique was adopted. Al-5,10wt%Pb, Al-8.5wt%Pb-1.5wt%Sn-4wt%Si-(1,3,5)wt%Cu powders were manufactured using centrifugal atomizer. The powders were cylindrical shape and showed bimodal size distribution. The effect of process variables on the dispersion characteristics of lead, tin, silicon and copper in aluminium matrix were investigated. Cooling rate during atomization was estimated from dendrite arm spacing. The estimated cooling rate was 10²-10??K sec.

저혈청 배지에서 인간 전골수세포(HL-60)를 이용한 tPA 생산과 세포사멸기작에 관한 연구

김현구,성기돈,김태호,안주희,함문선,박진서,이현용 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1

tPA 생산과 세포 사멸의 연구를 하기 위해서 인간 전골수세포가 배양되었다. 연속 관류 배양하에서 최대 tPA 생산량은 324 ng/ml이며 최대 세포 농도는 5.27×10 exp (6) cells/ml였다. Phorbol ester를 넣었을 때 tPA 생산량은 420 ng/ml까지 향상되었다. 형광 현미경으로 관찰했을 때, apoptosis는 세포 배양 초기부터 중반까지 우세했고 빠른 교반 속도에서도 우세했다. 그러나 necrosis는 세포배양 말기와 동결된 세포가 해동 되었을 때 우세했다. HL-60 was cultivated to produce tPA (tissue-type plasminogen activator) and study the mechanism of cell death. Maximum cell density and tPA production were obtained as 5.27×10 exp (6) cells/ml and 324 ng/ml, respectively under perfusion cultivation. tPA production was enhanced to 420 ng/ml in adding 160 nM of phorbol ester. The cells were gradually differentiated to granulocytes rather than proliferation. By Fluorescent microscope, apoptosis was prevailed except the death phase and in high agitation speed, but necrosis was prevailed in thawed cells and during the latter periods of the cultivation. It was also proved that tPA was most produced in apoptosis. To obtain higher tPA productivity, the cells must be maintained in apoptosis, not necrosis phase when the cells were dying.

선인장 재배농가의 농업정보 요구 조사

정구현,이해길,박인태,이철희 한국농업정보과학회 2000 농업정보과학 Vol.2 No.1

This study was performed to investigate the status of using personal computer(PC) and to develope strategy to improve PC utilization of Cactus Farmers. Sixty nine farmers are surveyed to collect data. Many farmers had intention to use PC to manage Cactus and have recognized that PC is required to manage farm and to improve their life quality. As a result of analysis on farmers' need for agricultural information, they highly demanded infor-mation on production skills, marketing information, overseas production trends, imports and exports information. Some farmers using or having intention to use software for Cactus farming want software to be developed and dis-tributed to support production technolog', labor management production cost and benefit analysis etc.

구상흑연 주철(FCD 60)의 조직과 기계적 성질에 미치는 Austemper의 영향

지태구 弘益大學校 産業技術硏究所 2005 産業技術 Vol.15 No.-

The effect of preheating at 700℃ on the microstructure and hardness of austemper spherodized graphite cast iron was studied. The austinite pool of austempered specimen after preheating was more refined and showed more homogeneous distribution than that without preheating. As the result of examination on the tempering process, it was supposed to the improvement of machinability of austemper spherodized graphite cast iron by preheating before austenitizing treatment.

공동주택 장기수선계획 시스템 개발을 위한 분석ㆍ설계단계에 관한 기초적 연구

서민구,정영한,박태근 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1

Extension of building life cycle and reduction of maintenance and management relevant expenses are the top issues in the current construction market. The fields of maintenance and management are newly highlighted for the limited land and domestic economic crisis known as the 2nd IMF. We studied on the long-term maintenance plan of apartment buildings in order to analyze the defective management system of existing apartment building and secure the development-oriented management system in this study. Purposes of this study are to prevent the unwanted loss of manpower and capital resulted from the careless storage of repair and management records, extend the building life cycle and resolve the conflict caused by the uncomfortable relation with the occupants. This study is focused on presenting the potential to develop the process required for the basic analysis and development of system as the beginning stage in the process of developing the long-term maintenance plan.

8주간의 Weight Training과 식이요법이 체지방 변화에 미치는 영향 : stress on the age of 20's female

윤규태,김진구 순천향대학교 기초과학연구소 2001 순천향자연과학연구 논문집 Vol.7 No.2

The purpose of this study was to compare the effects of examine body fat(%) changes following weight loss by diet with long term weight training exercise in women. The subjects of the present study were 180 women: 180 women's age were in range at 19 to 27, and their mean height were 163.1cm. also, their mean weight were 54.4kg, and their mean body fat(%) were 25.7%. The subjects were ready to begin exercise at the same time everyday following their own schedule. All subjects always measured their weight, height, and % body fat before starting every exercise time, and after 8 weeks. They were separated 3 different types of group. First group were doing only weight training during 8 weeks. Second group were doing only in diet program during the same period. Third group were in diet with weight training program. The weight and % body fat were significant differences after 8 weeks in the group which were doing diet with weight training program(p<0.05). However, the group that the weight loss range were light were no signifiant differences(p>0.05). after 8 weeks, their weight and % body fat of the group which were doing only weight training program were no significant differences(p>0.05). Also, their weight and % body fat of the group that were doing only diet program were no significant differences(p>0.05). In conclusion, diet and exercise are very necessary for losing weight and reducing % body fat. However we must do that together, so present study is showing us there are no good influence when we do that only one thing.

구상화흑연주철의 냉각변태거동에 미치는 오스테나이트화 온도의 영향

池泰求 홍익대학교 산업기술연구소 2001 産業技術 Vol.11 No.-

The purpose of this study is to clarify the continuous cooling transformation behavior of the spheroidal graphite cast ion during heat treatment at various austenitiged condition. When the specimen was furnace cooled, there was no effects of austenitinzing temperature on the microstructure and hardness value. In the case of water quenching as the austenitinzing temperature increased from 850℃ to 950℃, the high carbon plate martensite was coarsend and the amount of retained austenite increased. Air colling condition had the most effective austenitinzing temperature on hardenability of shpherodized cast iron among the cooling conditions and the higher asunitizing temperuture had superior hardenability.