• 대한기계학회논문집A
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• 제38권12호
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• pp.1325-1333
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• 2014

Near miss 방식 대응체의 충격자 분산 패턴은 위협체의 무력화에 큰 영향을 미친다. 본 연구에서는 near miss 방식 대응체의 원통형 텅스텐 충격자가 폭발에 의하여 분산될 경우 그 패턴을 수치해석적으로 분석하였다. 폭약의 질량과 형상을 충격자의 분산 패턴에 영향을 미치는 인자로 고려하였으며 두 가지 형상 모델 즉, 상부와 하부가 동일한 두께를 갖는 평행 형상과 상부 및 하부 두께가 각기 다른 테이퍼 형상으로 설정하였다. 해석 결과, 분산된 충격자는 임의 공간의 2 차원 평면상에서 고리 모양을 형성하였으며 폭약 형태가 동일한 경우 폭약 질량이 증가함에 따라 화망 면적은 증가하고, 아울러 테이퍼 형상 폭약의 경우, 평행 형상의 폭약에 비해 큰 화망 면적이 형성됨을 확인하였다. 화망 면적과 충격자 분산 밀도 평가를 바탕으로 near miss 방식 대응체의 충격자 분산 패턴 제어를 위해서는 물리적 특성, 즉 폭약의 질량뿐 만 아니라 형상 또한 주요 설계 요소가 됨을 알 수 있었다.

• 폴리머
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• 제34권3호
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• pp.253-260
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• 2010

본 연구에서는 조직확장 응용을 위한 생체적합성 생분해성 하이드로젤을 제조하고, 그 기본특성을 분석하였다. 친수성 고분자인 poly(ethylene glycol)의 양 말단에 다양한 몰비의 D,L-lactide와 glycolide를 개환 중합시켜 PLGA-PEG-PLGA 삼중공중합체를 합성한 뒤 비닐기를 도입하여 하이드로젤 제조 시 swelling/degradation controllers(SDC)로 사용하였다. 합성한 SDC와 PEG diacrylate를 사용하여 라디칼 중합으로 제조한 하이드로젤은 건조된 상태에서도 유연하고 탄성을 보였으며 분해테스트에서는 SDC의 조성과 SDC/PEG의 몰비에 따라 다양한 팽윤지연시간과 분해기간을 갖는 것으로 나타났다. 그 밖에 기계적 물성과 팽윤압력을 측정하였고, 이식시험을 통해 이식용 하이드로젤을 사용목적에 맞게 이식하거나 삽입하였을 때의 생체 조직의 국소적인 병리적 양상을 육안관찰과 현미경적 관찰을 통하여 평가하였다.

• 대한공업교육학회지
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• 제42권2호
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• pp.108-122
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• 2017

이 연구 논문은 인류 문명사에서 금자탑을 이루는 제 1차 산업혁명을 이끌고 성공적으로 이룬 와트에 관하여 그의 교육환경과 배움의 자세를 문헌을 통하여 살펴보고, 산업혁명의 결과물인 '새로운 증기기관'의 연구 개발 과정과 환경 등을 통하여 산업혁명을 이끄는 기본적인 인적 물적 인프라를 알아보는 데에 있다. 이러한 과정에서 얻어지는 정보는, 우리의 현재 학교교육이 지향하고 있는 '창의성 개발'에 관한 지침을 얻을 수 있다고 본다. 또한 아직은 태동기에 있는 '4차 산업혁명'을 대비하는 데에도 온고지신의 차원에서 많은 시사점을 얻을 수 있었다. 이상의 내용을 종합하여 얻은 주요 연구 결과는 다음과 같다. 첫째, 와트의 부모는 아들이 기계장치 등에 흥미를 가지고 있다는 것을 알고 이 분야의 타고난 재능을 살려주기 위하여 적극적으로 협조하였다. 둘째, 와트는 글라스고우 대학의 교수들과 인연을 맺고 자신의 관심분야를 스스로 개척하며, 자기주도 학습으로 지식을 흡수하였다. 이러한 학문에 관한 끊임없는 능동적인 자세는 그를 이 분야의 기술자 및 이론가로서 성장시켰다. 셋째, 18세기에 신분의 벽을 뛰어넘는 새로운 시대를 주도하는 Lunar society의 연구 환경 인프라는 와트에게 과학적 호기심과 자유로운 탐구 정신을 경험하게 한 협회이다. 자신의 과학기술지식을 발표하고, 서로 이에 대한 의견을 자유롭게 교환하며 집단적 사고방식을 바탕으로 문제-해결의 지식을 축적해 가는 시스템이 있다는 것은 현대의 R & D환경을 만들 때에도 유념하여야 할 사항이다. 넷째, 사업가 볼턴과 같이 기술을 이해하고 그 가치를 파악하는 능력이 구비된 '경영의 귀재'가 연구자들을 재정적으로 지원하는 시스템이 필요하다. 동시에 재정문제를 그다지 걱정하지 않고 기술 자체를 즐기고 연구하는 '기술의 달인' 와트와 같은 사람이 있어야 산업혁명은 잘 이루어질 수 있다.

• Clinical and Experimental Reproductive Medicine
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• 제39권1호
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• pp.15-21
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• 2012

Objective: Tributyltin (TBT), an endocrine disrupting chemical, has been reported to decrease ovarian function by causing apoptosis in the ovary, but the mechanism is not fully understood. Therefore, we examined whether TBT increases the expression of adipogenesis-related genes in the ovary and the increased expression of these genes is associated with apoptosis induction. Methods: Three-week-old Sprague-Dawley rats were orally administered TBT (1 or 10 mg/kg body weight) or sesame oil as a control for 7 days. The ovaries were obtained and weighed on day 8, and then they were fixed for terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) or frozen for RNA extraction. Using the total RNA of the ovaries, adipogenesis- and apoptosis-related genes were analyzed by real-time polymerase chain reaction (PCR). Results: The ovarian weight was significantly decreased in rats administered 10 mg/kg TBT compared to that in control rats. As determined by the TUNEL assay, the number of apoptotic follicles in ovary was significantly increased in rats administered 10 mg/kg TBT. The real-time PCR results showed that the expression of adipogenesis-related genes such as $PPAR{\gamma}$, ${\alpha}P2$, CD36, and PEPCK was increased after TBT administration. In addition, apoptosis-related genes such as $TNF{\alpha}$ and TNFR1 were expressed more in the TBT-administered rats compared with the control rats. Conclusion: The present study demonstrates that TBT induces the expression of adipogenesis- and apoptosis-related genes in the ovary leading to apoptosis in the ovarian follicles. These results suggest that the increased expression of adipogenesis-related genes in the ovary by TBT exposure might induce apoptosis resulting in a loss of ovarian function.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.266-272
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• 2002

The stochiometric mixture of evaporating materials for the ZnIn$_2$S$_4$ single crystal thin film was prepared from horizontal furnace. To obtain the ZnIn$_2$S$_4$ single crystal thin film, ZnIn$_2$S$_4$ mixed crystal was deposited on throughly etched semi-insulating GaAs(100) in the Hot Wall Epitaxy(HWE) system. The source and substrate temperature were 610 $^{\circ}C$ and 450 $^{\circ}C$, respectively and the growth rate of the ZnIn$_2$S$_4$ single crystal thin film was about 0.5 $\mu\textrm{m}$/hr. The crystalline structure of ZnIn$_2$S$_4$ single crystal thin film was investigated by photo1uminescence and double crystal X-ray diffraction(DCXD) measurement. The carrier density and mobility of ZnIn$_2$S$_4$ single crystal thin film measured from Hall effect by van der Pauw method are 8.51${\times}$10$\^$17/ cm$\^$-3/, 291 $\textrm{cm}^2$/V$.$s at 293 $^{\circ}$K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c - axis of the ZnIn$_2$S$_4$ single crystal thin film, we have found that the values of spin orbit splitting ΔSo and the crystal field splitting ΔCr were 0.0148 eV and 0.1678 eV at 10 $^{\circ}$K, respectively. From the photoluminescence measurement of ZnIn$_2$S$_4$ single crystal thin film, we observed free excition (E$\_$X/) typically observed only in high quality crystal and neutral donor bound exciton (D$^{\circ}$,X) having very strong peak intensity. The full width at half maximum and binding energy of neutral donor bound excition were 9 meV and 26 meV, respectively. The activation energy of impurity measured by Haynes rule was 130 meV.

• 한국환경농학회지
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• 제42권1호
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• pp.8-13
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• 2023

Biodegradation of antibiotics in soil can be affected by various environmental factors. This study was set to investigate the effect of environmental conditions such as soil pH and temperature on the degradation of oxolinic acid (OA), one of the agricultural antibiotics used in South Korea, in soil. Rice paddy soil (RS) and field soil (FS) were contaminated with OA and the soil pH was adjusted to 5.7±0.2, 6.8±0.2, and 7.6±0.1. The soil samples were kept at different temperatures (2.3±0.2, 23.0±0.6, 30.5± 0.3℃) for 30 d. The changes in the OA concentrations were determined at selected times. With the RS and FS, the OA removal was not affected by the soil pH used in this study; however, at pH 7.6, the OA removal in the RS was greater than that in the FS, which can be attributed to the different soil properties. The OA removal was similar at 23.0 and 30.5℃ in both soils, but was lower at 2.3℃. The information on the effect of different environmental conditions on the degradation of antibiotics in soil is very limited. Therefore, further studies are needed to better manage the residual antibiotics in the agricultural environment.

• 한국결정학회지
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• 제11권4호
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• pp.212-223
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• 2000

A stochiometric mix of CuInTe₂ polycrystal was prepared in a honizonatal furnace. To obtain the single crystal thin films, CuInTe₂ mixed crystal was deposited on throughly etched GaAs(100) by the HWE system. The source and substrate temperatures were 610℃ and 450℃ respectively, and the thickness of the deposited single crystal thin film was 2.4㎛. CuInTe₂ single crystal thin film was proved to be the optimal growth condition when the excition emission spectrum was the strongest at 1085.3 nm(1.1424 eV) of photoluminescence spectrum at 10 K, and also FWHM of Double Crystal X-ray Rocking Curve (DCRC) was the smallest, 129 arcsec. The Hall effect on this sample was measured by the method of Van der Pauw, and the carrier density and mobility dependent on temperature were 9.57x10/sup 22/ electron/㎥, 1.31x10/sup -2/㎡/V·s at 293 K, respectively. The ΔCr(Crystal field splitting) and the ΔSo (spin orbit coupling splitting( measured at f10K from the photocurrent peaks in the short wavelength of the CuInTe₂ single crystal thin film were about 0.1200 eV, 0.2833 eV respectively. From the PL spectra of CuInTe₂ single crystal thin film at 10 K, the free exciton (E/sub x/) was determined to be 1064.5 nm(1.1647 eV) and the donor-bound exciton(D/sup 0/, X) and acceptor-bound exciton (A/sup 0/, X) were determined to be 1085.3 nm(1.1424 eV) and 1096.8 nm(1.1304 eV0 respectively. And also, the donor-acciptor pair (DAP)P/sub 0/, DAP-replica P₁, DAP-replica P₂ and self-activated (SA) were determined to be 1131 nm (1.0962 eV), 1164 nm(1.0651 eV), 1191.1 nm(1.0340 eV) and 1618.1 nm (0.7662 eV), respectively.

• BMB Reports
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• 제46권2호
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• pp.124-129
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• 2013

FK506 binding protein 12 (FK506BP) belongs to a family of immunophilins, and is involved in multiple biological processes. However, the function of FK506BP in corneal disease remains unclear. In this study, we examined the protective effects on dry eye disease in a Botulinum toxin A (BTX-A) induced mouse model, using a cell-permeable PEP-1-FK506BP protein. PEP-1-FK506BP efficiently transduced into human corneal epithelial cells in a time- and dose-dependent manner, and remained stable in the cells for 48 h. In addition, we demonstrated that topical application of PEP-1-FK506BP was transduced into mouse cornea and conjunctiva by immunohistochemistry. Furthermore, topical application of PEP-1-FK506BP to BTX-A-induced mouse model markedly inhibited expression levels of pro-inflammatory cytokines such as interleukin-$1{\beta}$ (IL-$1{\beta}$), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and macrophage inhibitory factor (MIF) in corneal and conjunctival epithelium. These results suggest PEP-1-FK506BP as a potential therapeutic agent for dry eye diseases.

• 한국물환경학회지
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• 제29권4호
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• pp.514-522
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• 2013

The major 24 tributaries in Nam-River mid-watershed were monitored for discharge and water quality in order to understand the characteristics of the watershed and to select the tributary catchment for improving water quality. According to the analytical results of discharge and water quality monitoring data of 24 tributaries, the mean value of discharge below $0.1m^3/s$ was 62.5% among the monitored tributaries and it mostly exceeded the water quality standards of Nam-river mid-watershed ($BOD_5$ = 3 mg/L, T-P = 0.1 mg/L over). According to the stream grouping method and the water quality delivery load density ($kg/day/km^2$) based on the results of tributary discharge and water quality monitoring, the tributary watersheds for improving the water quality were selected. In the Nam-River mid-watershed, tributaries in the GaJwaCheon, HaChonCheon catchment (Group D, $BOD_5$ = 3 mg/L over) and in the UirYeongCheon, SeokGyoCheon catchment (Group A, T-P = 0.1 mg/L over), which have a small flow (and/or large flow) and a high concentrations of water pollutants. The various water quality improving scheme for tributaries, in accordance with the reduction of potential point source pollution by living sewage and livestock wastewater, should be established and implemented.

• Journal of Plant Biotechnology
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• 제44권3호
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• pp.335-342
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• 2017

Purple passion fruit (Passiflora edulis Sims) is one of the introduced tropical plants, an increasing interest has arisen due to its distinctive taste and attractive flavor. It is expected that passion fruit production and planted area will increase gradually in the years ahead because of high profitability and consumer's demands of healthful ingredients. So we tried to investigate the effect of plant growth regulators and antioxidants on in vitro plant regeneration and callus induction from leaf explants of passion fruit for an establishment of optimal mass propagation system. Young leaf explants of purple passion fruit were cultured in Murashige and Skoog (MS) medium containing different growth regulators and antioxidant additives to induce the shoot organogenesis. After 8 weeks, the highest embryogenic callus formation rate was obtained in MS medium supplemented with $1mg{\cdot}L^{-1}$ 6-benzylaminopurine (BAP) and $2mg{\cdot}L^{-1}$ 2,4-dichlorophenoxyacetic acid (2,4-D), furthermore, the shoot development via organogenesis was also observed. Silver nitrate ($AgNO_3$), which was added into the medium to minimize the adverse effects of leached phenolics, was effective for reduction of medium browning and sudden explant death. In the medium supplemented with $1mg{\cdot}L^{-1}$ BAP and $1mg{\cdot}L^{-1}$ gibberellic acid ($GA_3$), shoots were most vigorously regenerated and elongated. Most shoots rooted successfully in half strength medium with $1mg{\cdot}L^{-1}$ indol-3 acetic acid (IAA), and more than 90% of plantlets survived after 4-month acclimatization period.