• 대한기계학회논문집
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• 제11권3호
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• pp.501-508
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• 1987

본 연구에서는 입자발생 장치를 유동층(fluidized bed)을 이용하여 만들었고 이것에 의해서 고온의 연소가스속으로 입자가 공급되므로, 종래의 초음파입자 발생기 나 오리피스진동입자 발생기등에서 일어나는 호학반응 및 입자상호간의 응집(coagul- ation)현상등을 되도록 없게 하여 순수한 구형입자에 대한 입자부착 효과를 볼 수 있 게 함으로써, 부착기구의 이해와 해석등을 한층 유리하게 한다. 그리고 공급되는 입 자의 크기의 범위를 직경 0.2$\mu\textrm{m}$~30$\mu\textrm{m}$ 정도로 광범위하게 다루어 비교적 간단하고 잘 정의된 층류 유동에서, (1) 미세입자의 경우 실시간(real time) 레이져 광반사법에 의 한 입자부착률의 온도구배 및 농도에 대한 효과를 실험하고, (2) 입자의 Counting/Si- zing 법에 의하여 입자크기에 따른 열확산 효과 및 관성충돌 효과 등을 볼 수 있게 한 다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.268-268
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• 2006

YBCO 초전도 박막을 제조하기 위해 일반적으로 사용되는 RABiTS공정을 통해 제조된 양축 정렬된 Ni 선재 위에 직접 YBCO를 증착시키려는 시도가 많이 이루어졌다. Ni 위에 직접 증착시킨 YBCO 박막은 c-축으로 정렬되는 온도에서 Ni이 확산되어 YBCO와 반응하여 초전도 물성을 약화시킨다. 이것을 방지하기 위하여 완층층을 먼저 증착을 하는 연구를 시행하였다. 본 연구는 Ni-5at.%W(100) 기판위에 hot-wall type MOCVD (metal organic chemical vapor deposition)를 이용하여 증착을 실시하였다. 완층층으로는 Ni, YBCO와 각각 4.70%, 3.32%의 lattice mismatch를 갖는 $Yb_2O_3$를 선택하였으며, 증착 조건으로는 온도 $800\;{\sim}\;1000^{\circ}C$, 시간 3 ~ 10min, 증착압력 10 Torr의 조건에서 증착을 행하였다. $Yb_2O_3$를 형성하기 위해 산소를 이용하였으나 $Yb_2O_3$(200) 형성을 방해하는 NiO(111)이 형성되었다. 산소를 대신해 수증기를 이용하여 NiO 상이 없는 $Yb_2O_3$(200)을 형성하였다. 증착 시간과 수증기 압력에 따른 $Yb_2O_3$의 $I_{(200)}/(I_{(111)}+I_{(200)})$의 상대 회절강도비를 XRD (X-ray diffraction)를 이용하였고, 증착된 표면 형상은 SEM(scanning electron microscopy)을 통해 관찰하였다.

• 펄프종이기술
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• 제45권6호
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• pp.30-35
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• 2013

To conserve wood resources for papermaking, chemical compositions of the hemp (Cannabis sativa L.) bast fiber cultivated in Korea such as holocellulose, ${\alpha}$-cellulose, lignin, alcohol-benzene extractives, hot and cold water extractives, and ash contents were investigated to manufacture the specialty packaging paper effectively. Significantly very low klason lignin content of 3.3% was accomplished by removing of the outer shell of bark. Laboratory soda pulping method which is very useful for the nonwood fiber was adapted, and it was found that there was no significant difference in both kappa number and H-factor between 25% and 30% NaOH charge. Hemp pulp cooked with the laboratory digester in 25% NaOH at $170^{\circ}C$ were mixed together with the wood pulp(NBKP:LBKP=1:1) in order to find the optimum mixture ratio which exhibited acceptable paper strength properties such as tensile index, burst index, and tear strength. When 10% of hemp soda pulps was mixed with 90% of wood pulps comprised of SwBKP and HwBKP (1:1), all physical strength increased significantly. The physical strength decreased as the amount of hemp pulp increased because the cell wall of bast fiber is very thick which causes low conformability and low fiber-fiber bonding. These results showed that paper made of hemp-wood pulp can be used for the specialty packaging paper which requires both the characteristic surface properties and the high physical strength of hemp fiber.

• 한국추진공학회지
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• 제20권4호
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• pp.94-103
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• 2016

액체로켓엔진에서의 재생냉각 채널은 높은 온도의 연소가스로부터 연소실 내벽을 효율적으로 냉각하기 위해 사용되며, 냉각채널 설계를 위해서는 열전달 특성과 압력손실 특성을 미리 예측하여야 한다. 본 연구에서는 서로 다른 형상을 갖는 5개의 냉각채널을 설계하고, 커터와 엔드밀로 채널을 제작하였다. 채널을 흐르는 유속과 후단 압력조건을 달리하여 가공방법, 채널 형상, 유동조건에 따른 압력손실을 실험적으로 측정하여 해석결과와 비교를 수행하였다. 동일 형상 및 유동조건에서 커터로 가공된 채널이 엔드밀로 가공된 채널보다 압력손실이 적었다. 또한 채널 형상, 유동조건에 따라 실험결과와 해석결과의 압력손실 비가 달라짐을 확인할 수 있었다.

• 대한건축학회논문집:계획계
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• 제35권8호
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• pp.23-34
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• 2019

The façade, a fundamental function as a skin that protects human life from external environment such as cold and hot weather, snow, rain, and wind, etc, has served as a media for communication between indoor space of the building and outside space. From the media for communication point of view, the approach to envelope design, in which environmental elements are transmitted internally through the filtering of external environments, has been evolving in various ways from the past to the present. Today, modern architecture technologies including curtain wall systems and user-friendly computer programming and environmental analysis programs demonstrate a differentiated approach to envelope design related to the indoor environment. For this reason, it is worth noting that the envelope design factors and trends that appear variously in the UNStudio's projects before and after the 2000s. The factors reflected in the envelop design in conjunction with the indoor environment obtained through the case study of the UNStudio's office projects were daylight environment, thermal environment, ventilation, noise, privacy and view, and consideration for daylight environment and thermal environment was reflected in many cases through the case study. Looking at the changes in the diagrams in order of year, it can be seen that the envelope design using the environmental analysis tool has been performed since 2006. This is a clue to show the envelop design changes from the conceptual method to the data-based one. The diagrams and analysis results related to the envelop design showed that the thermal environment related to solar radiation was the most, and no diagrams and analysis related to the indoor illumination were found. Since 2010, PV panel installation has been shown in the envelope design, which can be found in the increased efficiency of PV panels due to the technological advances and the decrease in production cost.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.83-83
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• 2003

The stochiometric mix of evaporating materials for the CuInSe$_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CuInSe$_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were 62$0^{\circ}C$ and 41$0^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of CuInSe$_2$ single crystal thin films measured from Hall effect by van der Pauw method are 9.62$\times$10$^{16}$ cm$^{-3}$ , 296 $\textrm{cm}^2$/V.s at 293 K, respectively From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuInSe$_2$ single crystal thin film, we have found that the values of spin orbit splitting ΔSo and the crystal field splitting ΔCr were 6.1 meV and 175.2 meV at 10 K, respectively. From the photoluminescence measurement on CuInSe$_2$ single crystal thin film, we observed free excition (Ex) existing only high quality crystal and neutral bound exiciton (D$^{\circ}$,X) having very strong peak intensity. Then, the full-width-at -half-maximum(FWHM) and binding energy of neutral donor bound excition were 7 meV and 5.9 meV, respectivity. By Haynes rule, an activation energy of impurity was 59 meV.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.1-6
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• 2002

How is the flow in a rotating impeller. About 35 years have passed since one experimentalist rotating with the impeller. of a huge centrifugal blower made the flow measurements using a hot-wire anemometer (Fowler 1968). Optical measurement methods have great advantages over the intrusive methods especially for the flow measurement in a rotating impeller. One is the optical flow visualization (FV) technique (Senoo, et al., 1968) and the other is the application of laser velocimetry (LV) (Hah and Krain, 1990). Particle image velocimetries (PIVs) combine major features of both FV and LV, and are very attractive due to the feasibility of simultaneous and multi-points measurements (Hayami and Aramaki, 1999). A high-pressure-ratio transonic centrifugal compressor with a low-solidity cascade diffuser was tested in a closed loop with HFC134a gas at 18,000rpm (Hayami, 2000). Two kinds of measurement techniques by image processing were applied to visualize a flow in the compressor. One is a velocity field measurement at the inducer of the impeller using a PIV and the other is a pressure field measurement on the side wall of the cascade diffuser using a pressure sensitive paint (PSP) measurement technique. The PIV was successfully applied for visualization of an unsteady behavior of a shock wave based on the instantaneous velocity field measurement (Hayami, et al., 2002b) as well as a phase-averaged velocity vector field with a shock wave over one blade pitch (Hayami, et al., 2002a. b). A violent change in pressure was successfully visualized using a PSP measurement during a surge condition even though there are still some problems to be overcome (Hayami, et al., 2002c). Both PIV and PSP results are discussed in comparison with those of laser-2-focus (L2F) velocimetry and those of semiconductor pressure sensors. Experimental fluid dynamics (EFDs) are still growing up more and more both in hardware and in software. On the other hand, computational fluid dynamics (CFDs) are very attractive to understand the details of flow. A secondary flow on the side wall of the cascade diffuser was visualized based either steady or unsteady CFD calculations (Bonaiuti, et al.,2002). EFD and CFD methods will be combined to a hybrid method being complementary to each other. Measurement techniques by image processing as well as CFD calculations give a huge amount of data. Then, data mining technique will become more important to understand the flow mechanism both for EFD and CFD.

• Clinical and Experimental Reproductive Medicine
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• 제4권1호
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• pp.17-25
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• 1977

Anderson(1937), Power and Barnes(1941) reported a study concerning a method of tubal sterilization in association with peritoneoscopy or laparoscopy in which they cauterized the tubes. There appears to have been a hiatus of interest in sterilization (cold or hot) associated with laparoscopy until reintroduction by Palmer(1963), Frangenheim(1964) and Steptoe(1967). On the other hand, for interval female sterilization, however, minilaparotomy is relatively new. By Saunder and Munsick(1972), John Lyle(1974), Frank Stubb(1974), Vitoon(1973) and B.C. Bai(1975), their own technique for interval female sterilization requires 2.0 to 2.5cm, incision at the margin of the mons pubis. In Korea, female sterilization by means of minilaparotomy firstly reported by B.C. Bai using Bai's uterine elevator, of his own device, early in 1975. Recently inteval female sterilization by laparoscopy and minilaparotomy are widely accepted throughout the world especially in Asian countries. Minilaparotomy is carried out from 1974, laparoscopic sterilization from 1976, and in this study each of 250 cases of those were analysed and discussed for the comparison at Seoul Red Cross Hospital. (1) In the age distribution, numerous clients were in their age of $31{\sim}35$ in laparoscopy as well as minilaparotomy. Average 33.7 years in L and 33.2 years in M. (M=minilaparotomy, L=laparoscopic sterilization) (2) As regarding living children, women having 3 children represented the greatest number, 113 cases out of 250 in M group and 102 cases out of 250 in L group. Average No. of child are 2.9 in Land 3.1 in M. (3) Concidering the operation day in the menstrml cycle, the greatest number of cases, those who underwent tubal sterilization during the days of $26{\sim}$, next during the $6{\sim}10$ days of the cycle in both group. (4) Concidering the operation time, 188 cases by laparoscopy were performed in $6{\sim}10$ minutes, 33 cases within 5 minutes and 24 cases in $11{\sim}15$ minutes. Maximum 50 minutes, minimum 4 minutes and average 8.3 minutes. The majority of cases (154 cases) by minilaparotomy required $6{\sim}10$ minutes and 67 cases $11{\sim}15$ minutes, 6 cases within 5 minutes. Maximum 30 minutes, minimum 4 minutes and average 10.4, minutes. In both groups, most of the reasons for the extra length were surgical difficulties such as thick abdominal wall, pelvic adhesion, less cooperation of patients in early period of this study. (5) Hospital stay after operation in L group required $3{\sim}4$ hours in 125 cases, $2{\sim}3$ hours in 41 cases, $4{\sim}5$ hours in 32 cases out of 250. Maximum 8 hours, minimum 1 hour and average 3.8 hours. In M group hospital stay required $6{\sim}7$ hours in 100 cases, over 7 hours in 85 cases, $5{\sim}6$ hours in 46 cases and so on. Maximum 14 hours, minimum 2 hours and average 6.5 hours. (6) The time between operation and gas passing in the majority cases of both groups, were $12{\sim}36$ hours. A veragetime 20.3 hours in L and 27.2 in M. (7) Laparoscopic sterilization coincident with induced abortion were carried out in 27 cases, laparoscopy with minilaparotomy to control for mesosalpingeal hemorrhage in 1 case. Minilaparotomy coincident with induced abortion were performed in 65 cases, D and C whit polypectomy, menstrual regulatian, and remaval of IUD in 1 case respectively. (8) In L group, 1 case of mesosalpingeal hemorrhage, 1 case of abdominal wall infection were complicated during operation. In M group, 1 case of uterine perfaration, 1 case of abdominal wall infection, 1 case of hemorrhage from omentum and 1 case of bloody vaginal discharge were complicated. No intensive medical treatment was required for those minor complications in both groups. (9) No failure has been recognized and these two sterilization techniques might be the simple, safe and the most effective method for permanent contraception at present time. There is no significant clinical defference between L and M group in this study.

• 한국태양에너지학회 논문집
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• 제25권4호
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• pp.1-11
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• 2005

The stoichiometric mixture of evaporating materials for the $CuInSe_2$ single crystal thin film was prepared from horizontal furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal $CuInSe_2$, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were $5.783\;{\AA}$ and $11.621\;{\AA}$, respectively. To obtain the $CuInSe_2$ single crystal thin film, $CuInSe_2$ mixed crystal was deposited on throughly etched GaAs(100) by the HWE(Hot Wall Epitaxy) system. The source and substrate temperature were $620^{\circ}C$ and $410^{\circ}C$ respectively. The crystalline structure of $CuInSe_2$ single crystal thin film was investigated by the double crystal X-ray diffraction(DCXD). Hall effect on this sample was measured by the method of Van der Pauw and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by impurity scattering in the temperature range 30 K to 100 K and by lattice scattering in the temperature range 100 K to 293 K. The temperature dependence of the energy band gap of the $CuInSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.1851\;eV-(8.99{\times}10^{-4}\;eV/K)T^2/(T+153\;K)$. The open-circuit voltage, short current density, fill factor, and conversion efficiency of $n-CdS/p-CuGaSe_2$ heterojunction solar cells under $80\;mW/cm^2$ illumination were found to be 0.51V, $29.3\;mA/cm^2$, 0.76 and 14.3 %, respectively.

• 한국태양에너지학회 논문집
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• 제38권1호
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• pp.25-36
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• 2018

The stoichiometric mixture of evaporating materials for the $CaAl_2Se_4$: Co single crystal thin film was prepared from horizontal furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal $CaAl_2Se_4$, it was found orthorhomic structure whose lattice constant $a_0$, $b_0$ and $c_0$ were 6.4818, $11.1310{\AA}$ and $11.2443{\AA}$, respectively. To obtain the $CaAl_2Se_4$: Co single crystal thin film, $CaAl_2Se_4$: Co mixed crystal was deposited on throughly etched Si (100) by the HWE (Hot Wall Epitaxy) system. The source and substrate temperature were $600^{\circ}C$ and $440^{\circ}C$ respectively. The crystalline structure of $CaAl_2Se_4$: Co single crystal thin film was investigated by the double crystal X-ray diffraction (DCXD). Hall effect on this sample was measured by the method of Van der Pauw and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by impurity scattering in the temperature range 30 K to 100 K and by lattice scattering in the temperature range 100 K to 293 K. The temperature dependence of the energy band gap of the $CaAl_2Se_4$: Co obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=3.8239eV-(4.9823{\times}10^{-3}eV/K)T_2/(T+559K)$. The open-circuit voltage, short current density, fill factor, and conversion efficiency of $p-Si/p-CaAl_2Se_4$: Co heterojunction solar cells under $80mW/cm^2$ illumination were found to be 0.42 V, $25.3mA/cm^2$, 0.75 and 9.96%, respectively.