• 한국가축번식학회지
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• 제14권4호
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• pp.263-271
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• 1990

This study was carried out to investigate the factors affecting maturation in vitro of follicular oocytes in Korean Native Cattle. The bovine ovaries were obtained at a slaughter house and the follicular oocytes were recovered by aspirating the follicular fluid from the visible follicles of 3~6mm. The bovine oocytes were matured in vitro in TCM-199 containing FCS and hormones. The effects of TCM-199 salt type, number of oocytes per drop, incubation time and co-culture with granulosa cells on maturation of oocytes, were investigated. The results obtained are summarized as follows. 1. The maturation rates of follicular oocytes cultured for 22, 25 and 28 hours in Hank's TCM-199 or Earle's TCM-199 were 59.3, 59.6, 80% and 80.0, 90.0, 93.7%, respectively. The maturation rate of follicular oocytes in Earle's TCM-199 was faster and higher than in Hank's TCM-199(P<0.05). 2. The maturation rates of oocytes were 54.5, 62.5 and 62.0% when cultured the oocytes number 10, 20 and 40 per 200${mu}ell$ drop for 18 hours. 3. The maturation of follicular oocytes in the Korean Native Cattle was induced at 14 hours culture, by giving the maturation rate of 90.0% after 20 hours. 4. The maturation rates were 63.3% and 66.7%, respectigely when the oocytes were co-cultured with granulosa cells from medium-size follicles used immediately after recovery in the presence or absence of hormones added(0.02AU/ml FSH, 10$\mu\textrm{g}$/ml LH and 1$\mu\textrm{g}$/ml estradiol 17-$\beta$). When the oocytes were co-cultured with granulosa cells from medium-size follicles cultured for 3 days, the maturation rates were 20.8% and 76.2%, respectively(P<0.05). 5. The maturation rate were 88.0% and 70.0%, respectively when the oocytes were co-cultured with granulosa cells from large-size follicles used immediately after recovery in the presence or absence of hormones added(0.02AU/ml FSH, 10$\mu\textrm{g}$/ml LH and 1$\mu\textrm{g}$/ml estradiol 17-$\beta$)(P<0.05). When the hormones added(0.02AU/ml FSH, 10$\mu\textrm{g}$/ml LH and 1$\mu\textrm{g}$/ml estradiol 17-$\beta$)(P<0.05). When the oocytes were co-cultred with granulosa cells from large-size follicles cultured for 3 days, the maturation rates were 41.2% and 73.3%, respectively(P<0.05).

• 한국재료학회지
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• 제8권2호
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• pp.120-125
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• 1998

CO$_{2}$gas중에서 산화된 활성탄소섬유를 77K에서 질소흡착에 의해 흡착등온곡선을 구하였다. 미세공부피와 외부표면적은 t-법으로 구하였으며, 평균기공크기와 기공분포는 Dubinin-Astakhov법으로 구하여 기공발당과정을 고찰하였다. 산화반응 초기(약 40% burn-off까지)에 섬유내부에 발달하는 미세공은 burn-off가 40%를 넘으면 서서히 큰 미세공으로 성장하며, burn-off가 약 60%이상되면 미세기공은 확대 또는 합체되어 점차 중기공으로 성장하는 것으로 관찰되었다. 또한 고온산화반응으로 발달한 기공은 저온에서 생성된 기공보다 크다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권1호
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• pp.20-30
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• 2001

A 1.8V $650{\;}\textrm{mm}^2$ 4Gb DRAM having $0.10{\;}\mu\textrm{m}^2$ cell size has been successfully developed using 0.11 $\mu\textrm{m}$DRAM technology. Considering manufactur-ability, we have focused on developing patterning technology using KrF lithography that makes $0.11{\;}\mu\textrm{m}$ DRAM technology possible. Furthermore, we developed novel DRAM technologies, which will have strong influence on the future DRAM integration. These are novel oxide gap-filling, W-bit line with stud contact for borderless metal contact, line-type storage node self-aligned contact (SAC), mechanically stable metal-insulator-silicon (MIS) capacitor and CVD Al process for metal inter-connections. In addition, 80 nm array transistor and sub-80 nm memory cell contact are also developed for high functional yield as well as chip performance. Many issues which large sized chip often faces are solved by novel design approaches such as skew minimizing technique, gain control pre-sensing scheme and bit line calibration scheme.

• Journal of Biosystems Engineering
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• 제24권2호
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• pp.107-114
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• 1999

To find the best combustion conditions in the heavy oil burner kinetic viscosity of heavy oil A, B and C at different temperature range, from 40 to 140$^{\circ}C$, and the droplet sizes of the heavy oils at different temperature and pump pressure were measured. And, combustion characteristics were investigated under the different conditions : two different heavy oil and three different oil temperature. At temperature of 70, 100, 130$^{\circ}C$ the kinetic viscosity of heavy oil A and B are 7.9, 5.7, 4.3 and 30.4, 13.7, 7.9cSt, respectively. The greatest and smallest viscosity were 7,455 cSt at C oil on 27$^{\circ}C$ and 4.26cSt at A oil on 140$^{\circ}C$. The magnitude of viscosity difference between at 100$^{\circ}C$ and 140$^{\circ}C$ under 6 cSt in cases of A and B oil, but more than 30cST on C oil. Of the droplet sizes, the biggest and smallest droplet size in A oil were 98$\mu\textrm{m}$ at oil temperature of 130$^{\circ}C$(4.3cSt), pump pressure of 1.57MPa and 72$\mu\textrm{m}$ at 70$^{\circ}C$(7.9cSt), 2.35MPa, respectively. It appeared that as spraying pressure increased the droplet size decreased, however, no distinct differences were found in the effects of kinetic viscosity on the droplet sizes of the test range. The best combustion performance was observed when droplet size, spraying pressure and oil temperature were 73$\mu\textrm{m}$, 2.35MPa and 70$^{\circ}C$ producing CO2 of 13.1%, CO of 13ppm and flue gas temperature of 250$^{\circ}C$ in A oil combustion For B oil, it was100$^{\circ}C$, 2.35MPa, 52$\mu\textrm{m}$, producing CO2 of 10ppm and flue gas temperature of 260$^{\circ}C$. In general, it appeared that better combustion results were observed in the smaller droplets produced burner condition.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.431-434
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• 1998

Platinum-Cobalt alloy thin films were deposited on Al$_2$O$_3$ substrate by r.f. cosputtering for RTD temperature sensors. We made Pt-Co alloy resistance patterns on the Al$_2$O$_3$ substrate by lift-off method and investigated the physical and electrical characteristics of these films under various conditions (the input power, working vacuum, annealing temperature, thickness of thin films) and also after annealing these films. At input power of Pt : 4.4 W/$\textrm{cm}^2$, Co : 6.91 W/$\textrm{cm}^2$, working vacuum on and annealing conditions of 1000 $^{\circ}C$ and 60 min, the resistivity and the sheet resistive thin films were 15 ${\mu}$$\Omega$$.$cm and 0.5 $\Omega$/$\square$, respectively. The TCR value of Pt-Co a films was measured with various thickness of thin films and annealing temperature. T TCR value is gained under condition 3000${\AA}$ of thin films thickness and 1000$^{\circ}C$ of temperature. These results indicate that Pt-Co alloy thin films have potentiality for the wide temperature ranges.

• 한국재료학회지
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• 제8권10호
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• pp.912-917
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• 1998

화학적 산화막(SiOx)이 형성된 Si(100)기판 위에 Co-silicide의 형성과 계면 형상에 관한 연구를 하였다. 화학적 산화막은 과산화수소수(H2O2)의 인위적 처리에 의해 약 2nm을 형성시켰다. 그 위에 5nm 두께의 Co 박막을 전자빔 증착기에 의해 증착시킨 후 열처리하여 Co-silicide를 형성하였다. 화학적 산화막 위에서 Co-silicide 반응기구를 알아 보기 위해 $500^{\circ}C$-$900^{\circ}C$의 온도 범위에서 ex-situ와 in-situ 열처리를 하였다. 이와같이 형성된 Co-silicide 시편의 상형성, 표면 및 계면 형상, 그리고 화학적 조성을 XRD, SEM, TEM, 그리고 AES를 이용하여 분석하였다. 분석 결과 es-situ 열처리시 $700^{\circ}C$까지 CoSi2 상은 형성되지 않았고 Co의 응집화현상이 일어났다. $800^{\circ}C$ 열처리한 경우에는 CoSI2가 형성되었고 facet 현상이 크게 나타났으며 불연속적인 grain 들이 형성되었다. In-situ 열처리한 경우에는 저온에서 ($550 ^{\circ}C$)반응하여 Co-silicide가 형성되기 시작하였으며 $600^{\circ}C$부터는 facet에 의해 박막의 특성이 나빠지기 시작했다. $550^{\circ}C$에서 Co가 화학적 산화막 층을 통해 확산하여 균질한 Co-silicide를 형성하였다. 이와같이 형성된 균질한 실리사이드 층을 이용하여 다단계(55$0^{\circ}C$-$650^{\circ}C$-$800^{\circ}C$)열처리에 의해 균질한 다결정 CoSI2의 형성이 관찰되었다.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.763-768
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• 2004

To investigate the feasibility of developing a new quercetin transdermal system, a preformulation study was carried out. Therefore, the effects of vehicles and pressure-sensitive adhesives (PSA) on the in vitro permeation of quercetin across dorsal hairless mouse skin were studied. Among vehicles used, propylene glycol monocaprylate (PGMC) and propylene glycol mono-laurate were found to have relatively high permeation flux from solution formulation (i.e., the permeation fluxes were 17.25$\pm$1.96 and 9.60$\pm$3.87 $\mu\textrm{g}$/$\textrm{cm}^2$/h, respectively). The release rate from PSA formulations followed a matrix-controlled diffusion model and was mainly affected by the amount of PSA and drug loaded. The overall permeation fluxes from PSA formulations were less than 0.30 $\mu\textrm{g}$/$\textrm{cm}^2$/h, which were significantly lower compared to those obtained from solution formulations. The lower permeation fluxes may be due to the decrease of solubility and diffusivity of quercetin in the PSA layer, considering the fact that the highest flux of 0.26 $\mu\textrm{g}$/$\textrm{cm}^2$/h was obtained with the addition of 0.2％ butylated hydroxyanisole in PGMC-diethyl-ene glycol monoethyl ether co-solvents (80-85 ： 15-20, v/v). Taken together, these observations indicate that improvement in the solubility and diffusivity of quercetin is necessary to realize fully the clinically applicable transdermal delivery system for the drug.

• 한국가축번식학회지
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• 제25권2호
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• pp.93-100
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• 2001

본 연구는 개 난자의 체외성숙을 유도하기 위하여 발정기 및 비발정기의 개로부터 난소를 채취하여 난자의 채취율과 채취된 난자의 크기와 배양액의 종류에 따른 핵 발달율을 조사하기 위하여 수행되었다. 본 연구를 위하여 난소의 채취는 순천축산에서 난소적출술로 회수하여 3$0^{\circ}C$ saline에 담아 실험실로 2시간 이내에 수송하였다. 모든 난소는 항생제가 첨가된 saline으로 3-4회 세척 후 100 mm dish에서 blade로 세절하여 미성숙난자를 회수하였다. 회수된 난자는 발정기와 비발정기 및 110 $\mu\textrm{m}$ 이상과 이하로 구분하여 회수율을 조사하였다. 미성숙난자의 핵 발달을 유도하기 위하여 체외성숙 배양액은 TCM199과 $\alpha$-MEM에 10% FCS, 0.1 mg/$m\ell$ sodium pyruvate, 100 ng/$m\ell$ FSH, 100 ng/$m\ell$ EGF, 1% 775, 100 lU/$m\ell$ penicillin, 100 $\mu\textrm{g}$/$m\ell$ streptomycin 등을 첨가하여 38.5$^{\circ}C$, 5% $CO_2$ incubator에서 72시간 동안 배양하였다. 핵발달율은 45% acetic acid 용액으로 48시간 고정 후 1% Orcein으로 염색하여 조사하였다. 발정기의 난소로부터 110 $\mu\textrm{m}$ 이상의 난자의 회수율 (63.6%)은 비발정기(51.5%)의 것보다 유의적으로 높았다 (P＜0.05). 발정기의 난소에서 110 $\mu\textrm{m}$ 이상의 난소당 난자회수율 (22.6개/63.8%)은 비발정기의 것보다 유의적으로 높았다 (P ＜ 0.05). 발정기의 난소에서 110 $\mu\textrm{m}$ 이상의 난자의 MI까지의 핵발달율 (24.3%)은 110 Um이하의 것 또는 비발정기의 110 $\mu\textrm{m}$ 이상 및 이하의 난자의 것보다 유의적으로 높았다 (2.5, 6.8 및 0.0%; P ＜0.05). 발정기의 110 $\mu\textrm{m}$ 이상 난자의 AT 또는 MII까지의 핵 발달율은 다른 처리군보다 높게 발달하였다. TCM199에서 MI까지의 핵발달율 (21.8%)은 $\alpha$-MEM (10.0%)보다 유의적으로 높았다 (P＜ 0.05). 그러나 AT까지의 핵 발달율은 TCM199 (7.3%)과 (-MEM (1.1%) 간에는 유의적 차이가 있었으나 (P＜0.05), MII까지는 TCM199 (0.9%)과 (-MEM (1.1%)에는 유의차가 없었다. 본 연구결과는 110 $\mu\textrm{m}$ 이상의 난자는 발정기의 난소로부터 더 많은 난자를 회수할 수 있었고, 110 $\mu\textrm{m}$ 이상의 난자들이 MI, AT까지의 핵발달 능력이 높았다. 또한 체외성숙배양액 시 TCM199이 $\alpha$-MEM보다 Mi과AI까지 높은 발달율을 보였다.

• 한국분말재료학회지
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• 제1권1호
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• pp.42-51
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• 1994

6061Al-SiCP metal matrix composite materials(MMCs) were fabricated by injecting SiCP particles directly into the atomized spray. The main attraction of this technique is the rapid fabrication of semi-finished, composite products in a combined atomization, particulate injection(10 $\mu\textrm{m}$, 40 $\mu\textrm{m}$, SiCP) and deposition operation. Conclusions obtained are as follows; The microstructure of the unreinforced spray formed 6061Al alloy consisted of relatively fine(50 $\mu\textrm{m}$) equiaxed grains. By comparision, the microstructure of the I/M materials was segregated and consisted of relatively coarse(150 $\mu\textrm{m}$) grains. The probability of clustering of SiCP particles in co-sprayed metal matrix composites increased it ceramic particle size(SiCP) was reduced and the volume fraction was held constant. Analysis of overspray powders collected from the spray atomization and deposition experiments indicated that morphology of powders were nearly spherical and degree of powders sphercity was deviated due to composite with SiCp particles. Interfacial bonding between matrix and ceramics was improved by heat treatment and addition of alloying elements(Mg). Maximum hardness values [Hv: 165 kg/mm2 for Al-10 $\mu\textrm{m}$ SiCp Hv--159 kg/mm2 for Al-40 $\mu\textrm{m}$SiCp] were obtained through the solution heat treatment at $530^{\circ}C$ for 2 hrs and aging at $178^{\circ}C$, and there by the resistance were improved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.232-235
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• 2002

An 150 kV gas cluster ion accelerator was fabricated and assessed. The change of surface morphology and surface roughness were examined by an atom force microscope (AFM) after irradiation of $CO_2$ gas clusters on Si (100) surfaces at the acceleration voltages of 50 kV. The density of hillocks induced by cluster ion impact was gradually increased with the dosage up to 5$\times$10$^{11}$ ions/$\textrm{cm}^2$. At the boundary of the ion dosage of 10$^{12}$ ions/$\textrm{cm}^2$, the density of the induced hillocks was decreased and RMS (root mean square) surface roughness was not deteriorated further. At the dosage of 5x10$^{13}$ ions/$\textrm{cm}^2$, the induced hillocks completely disappeared and the surface became very flat. In addition, the irradiated region was sputtered. $CO_2$ cluster ions are irradiated at the acceleration voltage of 25 kV to remove hillocks on indium tin oxide (ITO) surface and thus to attain highly smooth surfaces. $CO_2$ monomer ions are also bombarded on the ITO surface at the same acceleration voltage to compare sputtering phenomena. From the AFM results, the irradiation of monomer ions make the hillocks sharper and the surfaces rougher On the other hand, the irradiation of $CO_2$ cluster ions reduces the hight of hillocks and planarize the ITO surfaces. From the experiment of isolated cluster ion impact on the Si surfaces, the induced hillocks m high had the surfaces embossed at the lower ion dosages. The surface roughness was slightly increased with the hillock density and the ion dosage. At higher than a critical ion dosage, the induced hillocks were sputtered and the sputtered particles migrated in order to fill valleys among the hillocks. After prolonged irradiation of cluster ions, the irradiated region was very flat and etched.