• 폴리머
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• 제32권3호
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• pp.199-205
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• 2008

단백질 및 펩타이드의 서방형 약물전달체로서 소장점막하조직(SIS)으로 개질된 PLGA 담체를 제조하고자 하였으며, SIS/PLGA 담체는 용매 캐스팅/염 추출법에 의해 준비된 PLGA 담체에 SIS 용액을 첨가하여 단순 함침방법으로 제조하였다. 본 실험에서 사용된 돼지의 소장 점막층에서 유래된 SIS는 면역거부반응이 적어 생체재료로 널리 사용되고 있다. 제조된 PLGA 및 SIS/PLGA 담체를 SEM을 통한 표면 및 내부 관찰결과 두 담체 모두 열린 다공구조를 이루며, 특히 SIS/PLGA 담체는 PLGA 담체의 다공 내부에 SIS가 침투되어 작은 네트워크를 형성하고 있음을 확인하였다. 또한 단백질의 방출경향을 확인하기 위하여 형광이 결합된 소 혈청 알부민(FITC-BSA)을 PLGA 및 SIS/PLGA 담체에 담지시킨 후, 형광광도계를 통해 이들의 방출거동을 확인하였다. PLGA 담체와 비교할 때 SIS/PLGA 담체에서의 BSA의 방출은 초기방출량이 적고 지속적으로 일정량이 방출되는 거동을 확인할 수 있었으며 함량별 BSA 농도에 따른 SIS/PLGA 담체에서의 방출은 BSA의 양이 증가할수록 빠르고 많은 양이 방출되는 경향성 있는 방출패턴을 보임을 확인하였다. 결론적으로 PLGA 담체에 침투한 SIS 젤이 BSA의 급격한 초기방출을 억제하며, SIS로 개질된 PLGA 담체는 방출조절이 가능한 약물전달체로서 매우 유용할 것으로 사료된다.

• 대한수학회보
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• 제44권4호
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• pp.631-640
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• 2007

The purpose of this article is to deal with the multiple values and uniqueness of meromorphic functions with small functions in the whole complex plane. We obtain a more general theorem which improves and extends strongly the results of R. Nevanlinna, Li-Qiao, Yao, Yi, and Thai-Tan.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1999년도 동계 학술대회 논문집
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• pp.444-459
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• 1999

• 폴리머
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• 제32권1호
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• pp.26-30
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• 2008

추간판 디스크의 섬유륜(AF)조직 재생에 적합한 다양한 담체를 평가하기 위해 천연재료인 소장점막하조직(SIS)과 탈미네랄화된 골분(DBP)을 폴리(락타이드-글리콜라이드) 공중합체(PLGA)와 혼합하여 담체(PLGA/SIS, PLGA/DBP, PLGA/SIS/DBP)를 제조하였으며, PLGA담체, PGA 메쉬, SIS 스폰지와 비교하였다. 제조된 담체의 압축강도 및 AF 세포를 담체에 파종하여 콜라겐 양과 DNA량을 측정하였으며, 이를 누드마우스 피하에 이식 후 적출하여 육안관찰과 조직학적인 평가를 수행하였다. 압축강도 측정에서 PLGA와 유사하게 PLGA/SIS, PLGA/DBP 에서도 충분한 강도를 나타내었다. DNA 증가량에 따른 콜라겐 양은 PLGA/SIS 에서 가장 높게 나타났고, 면역화학 염색을 통해 PLGA/SIS, PLGA/SIS/DBP 에서 글라이코스아미노글라이칸과 콜라겐 발현량이 높음을 확인하였다.

• Asia-Pacific Journal of Atmospheric Sciences
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• 제54권4호
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• pp.587-598
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• 2018

The impacts of aerosol loading on surface precipitation from mid-latitude deep convective systems are examined using a bin microphysics model. For this, a precipitation case over north central Mongolia, which is a high-altitude inland region, on 21 August 2014 is simulated with aerosol number concentrations of 150, 300, 600, 1200, 2400, and $4800cm^{-3}$. The surface precipitation amount slightly decreases with increasing aerosol number concentration in the range of $150-600cm^{-3}$, while it notably increases in the range of $600-4800cm^{-3}$ (22% increase with eightfold aerosol loading). We attempt to explain why the surface precipitation amount increases with increasing aerosol number concentration in the range of $600-4800cm^{-3}$. A higher aerosol number concentration results in more drops of small sizes. More drops of small sizes grow through condensation while being transported upward and some of them freeze, thus increasing the mass content of ice crystals. The increased ice crystal mass content leads to an increase in the mass content of small-sized snow particles largely through deposition, and the increased mass content of small-sized snow particles leads to an increase in the mass content of large-sized snow particles largely through riming. In addition, more drops of small sizes increase the mass content of supercooled drops, which also leads to an increase in the mass content of large-sized snow particles through riming. The increased mass content of large-sized snow particles resulting from these pathways contributes to a larger surface precipitation amount through melting and collision-coalescence.

• 한국농공학회지
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• 제35권2호
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• pp.92-103
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• 1993

A sunday system with a horizontal bin-type composter was constructed and operated to evaluate its composting performance for four days for each test in October, 1992. A sundry system is one of popular systems for composting livestock manure, of which main benefit is to utilize unlimited, clean, and free solar radiation. A rectangular concrete bin(composter) with dimension of 300cm(length) X90cm(width) X60cm(height) was bedded alternatively with four lanes of aeration pipes and heating pipes, and was insulated at three walls with 50mm styrofoam. Each aeration pipe of a diameter of 25mm had 4mm perforated holes at every 15cm longitudinally, and supplied air of about 2m$^3$/min to the composter to maintain aerobic condition . A stirrer rotating at 1 rpm made one round trip every 20 minutes on the conveying chain along the the length of the composter. Five tests (Test 1~Test 5) were implemented to evaluate the composting effectiveness of a sundry system with a horizontal bin-type composter. Treatments of two levels of the mixture ratio of swine manure and paper sludge cakes(manure : paper sludge cakes= 1 : 4 and 1 : 2) and two levels of the water content(W/C ; 70% and 50%) were made to test the significance of the physicochemical properties for decomposition of the mixture materials. Temperature, C/N ratio, water content, microbial activity of the composting materials were taken measurements to evaluate its performance with the lapse of composting time for tests. A small-scale sundry system with a bin-type composter did not appear to be an appropriate system for composting livestock manure. Since heat generation by the composting materials could not overcome heat loss due to areation in a small-scale composter, a proper thermal enviroment could not be maintained to propagate massively thermopilic microorganism relatively in a short period of time. Different from the result of Chol et al.(1992) 6), a temperature variation of the composting materials did not show the peak clearly and C/N ratio didn't lower with time as expected. Mesophilic microoragnism seemed to play an important role for decomposition of the mixture materials. A sundry system with a bin-type composter may be good for a large-scale livestock farm household which may produce enough animal manure. Therefore a decision should be made very carefully to choose a system for composting livestock waste.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2390-2392
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• 2001

The small gear head noise is caused by gear accuracy, assembling errors, and gear backlash. This main study is an investigation on noise quality of the small gear head through the change of gear backlash. In this study included gear design parameters related the small gear head, the knowledge of rattle noise related gear backlash, and the experimentation results of the small head noise through change of gear backlash. At last, this study propose the least method of the small gear head noise that is caused by suitable existence of gear backlash.

• 한국안전학회지
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• 제28권2호
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• pp.84-87
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• 2013

National industrial accidents, most recently occurred in the small to medium-sized industries. These companies' management for the prevention of industrial accidents, the role of the supervisor has emerged as an important issue. Small to medium-sized industries to enhance their effectiveness in the prevention of industrial accidents supervisors of work status survey and direct interviews were conducted. Proposal paper was based on the results of analysis for the role of supervisors by providing safety and health work systematically to participate.

• 산업경영시스템학회지
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• 제36권4호
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• pp.9-17
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• 2013

The purpose of this study is to figure out the impacts of technological innovation and cost management on productivity in small shipping industries to come up with developmental implications. To achieve this, a survey was carried out to 150 workers in small shipbuilding industries through April 2 to April 20, 2012. As for findings stated above, technological innovation and cost management in the Korean small shipbuilding industries were key factors that elevate financial and non-financial productivity. In the light of low technological prowess and cost structure of small shipbuilding industries, their productivity can be improved when intensive cost management with production factor technology as know-how is realized through quality management, which product development technology is the top priority as an independent niche strategy. Consequently, the combination of infrastructures in small shipbuilding industries with continuous efforts for cost reduction by the link to the systematized structure can't only secure their independent competitiveness, but raise their productivity.

• 한국환경농학회지
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• 제20권3호
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• pp.135-142
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• 2001

가정에서 발생되는 퇴비화 가능한 폐기물 중 종이류 및 골판지 등을 제외한 것을 퇴비화 용기에 투입하기 전에 주방용 야채 분쇄기로 잘게 분쇄한 것(Case III)과 가정에서 비용을 들이지 않고 간단하게 실행할 수 있는 방법인 손으로 대충 찢는 것(Case II)으로 퇴비화하면서 분해율과 생산된 퇴비의 이${\cdot}$화학성을 조사하였다. 퇴비화과정 중 퇴비화용기의 습윤 및 건조 상태 잔류 퇴비화물질의 양에 대한 회귀직선식들은 각각 $R^2$ 값이 0.95 및 0.90 이상으로 이들 식들을 이용한 잔류 퇴비화물질의 양에 대한 예측이 가능하였다. 하루 전체 퇴비화물질의 무게 감소율은 Case II와 III의 경우 각각 6.82% 및 6.93%이었으나 투입된 퇴비화 가능한 가정 폐기물만에 대한 하루 무게 감소율은 56.43% 및 53.30%로 하루 전체 퇴비화물질의 무게 감소율보다 대단히 높았다. 하루 전체 퇴비화물질의 분해 율은 Case II와 III의 경우 각각 8.81% 및 7.70%이었으나 투입된 퇴비화 가능한 가정 폐기물만에 대한 하루 분해율은 각각 19.26% 및 22.95%로 주방용 야채 분쇄기로 거의 죽 상태로 분쇄하였을 경우(Case III) 분해율이 약간 높았다. 생산된 퇴비 중 이${\cdot}$화학적 특성은 Case II와 III의 경우 예상된 바와 같이 큰 차이는 없었다.