• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.213-218
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• 2011

The scope of homogeneous Lewis acid-catalyzed benzo[N,N]-heterocyclic condensation was expanded to include the use of various metal salts not reported in the literature and $SnCl_2{\cdot}2H_2O$ was finally selected. Among various solid supports activated with $SnCl_2$, heterogeneous $SnCl_2/SiO_2$ proved to be the most effective and significantly higher conversions were achieved compared to $SnCl_2{\cdot}2H_2O$ itself. The results of TG-DTA and BET indicated that dispersed $SnCl_2$ coordinates with surface hydroxyl groups of silica leading to formation of stable Lewis acid sites. Low catalyst loading, operational simplicity, practicability and applicability to various substrates render this eco-friendly approach as an interesting alternative to previously applied procedures.

• 환경정책연구
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• 제6권1호
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• pp.61-81
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• 2007

농산물에 대한 시장수요는 가격탄력성이 작기 때문에 기술진보나 여타 생산성 향상요인에 의해 공급이 확대되면 시장가격이 크게 하락하고 농가의 이윤은 감소한다. 일반적인 경쟁시장 작동원리에 따르면 농업 부문에 투입된 부존자원은 다른 산업으로 조정될 것이다. 하지만 농업부문의 경우 다른 산업으로의 신축적인 자원조정(resource adjustment)이 이루어지지 않기 때문에 농산물의 과다 생산과 낮은 소득수준이 지속된다. 정부가 농업부문 보호를 위해 다양한 정책수단을 도입하는 근본적인 이유는 농업부문이 다른 산업에 비해 취약한 수익구조를 가지고 있어 경쟁시장에서는 식량안보라는 편익을 사회적으로 적절한 수준에서 제공하지 못하기 때문이다. 농업부문 보호를 위해 정부가 취하는 대표적인 정책은 가격지지정책과 소득보조정책이다. 직접지불제는 정부가 농가의 소득을 직접적으로 지지하는 보조금의 한 형태로 농산물의 가격과 교역조건에 직접적인 영향을 미치지 않아 WTO농업협정의 감축대상 보조금에서 제외되어 최근 새로운 농업보호 수단으로 운용되고 있다. 친환경직불제는 환경보전형 농업에 대한 직접지불제로 농약이나 화학비료를 사용하지 않고 생산하는 농가에 대해 일정 보조금을 지급하는 제도이다. 국내에서 1999년부터 시행되고 있는 친환경직불제는 유기농산물의 공급을 확대시키고 농업시장 개방에 대응한 농업부문의 경쟁력 제고방안을 제시하였다는 점에서 긍정적으로 평가되고 있다. 하지만 실제 공급되는 친환경농산물이 저농약이나 무농약농산물이라는 점과 유기질비료 사용을 적절하게 조절하지 못하고 있다는 점에서 '환경보전형 농업'인지에 대해서는 장담할 수 없는 실정이다. 현행 친환경직불제하에서 농약과 화학비료의 투입량이 감소하는 것은 명확하다. 하지만 유기질비료의 투입이 증가한다는 것도 명확하다. 따라서 농약과 화학비료의 감소에 따른 환경질 개선정도가 유기질비료 투입 증가에 의해 상쇄된다면 친환경직불제의 '친환경성'은 보장되지 않는다. 만약 비료에 대한 수요가 큰 농가를 중심으로 친환경농업이 이루어진다면 친환경직불제의 환경오염 저감잠재력은 더욱 취약해질 것이다. 본 논문은 친환경농업으로의 전환에 대한 유인을 정의하고 낮은 토양질의 농가들이 전환에 더 큰 유인을 갖게 됨을 보이고 있다.

• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.204-209
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• 1994

The synthesis of N-(benzyloxycarbonyl)-L-aspartyl-L-phenylalanine methylester (Z-APM), a precursor of aspartame, from N-(benzyloxycarbonyl)-L-aspartic acid (Z-Asp) and L-phenylalanine methylester hydrochlolide($L-PM\cdot HCI$) was investigated in a saturated-ethylacetate single phase system using immobilized thermolysin. Among the various supports tested, glyceryl-CPG was found to be most efficient for retaining enzyme activity. The enzyme immobilized onto glyceryl-CPG also showed the highest activity for Z-APM synthesis in saturated ethyl acetate. Z-APM conversion yield in saturated ethylacetate was half of that obtained in an ethyl acetate-buffer two-phase system under the same reaction conditions. However, as the mole ratio of $L-PM \cdot HCI$ to Z-Asp was increased to 4.0, the conversion yield reached 95 %. When continuous synthesis of Z-APM was canied out in a plug flow reactor (PFR) with 80 mM of L-PMㆍHCI and 20 mM of Z-Asp in saturated ethylacetate (pH 5.5), more than 95 % of Z-Asp was converted to Z-APM with a space velocity of 1.16 $hr^{-1} at 40^{\circ}C$. Although the operational stability in PFR was reduced rapidly, more than 80% of initial activity was maintained in CSTR even after a week of operation.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.14-17
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• 2002

To increase the efficiency of a two-stage anaerobic wastewater digestion system, various polymers were added to the methanogenic reactor as supports. The addition of polyurethane addition (6%, w/v) to the methanogenic reactor facilitated the organic loading rate (2-day Hydraulic Retention Time), higher than that of the conventional methanogenic reactor (6-day HRT). During the operation of the polyurethane-added reactor, a significant decrease in the organic mass in the effluent (COD 5-6 kg/l) was achieved, compared to that of the conventional reactor (COD 15-20 kg/l). The methane gas production rate also improved about 3-fold in the polyurethane-added reactor. More biomass was found to accumulate in the polyurethane-liquid phase (volatile solid, 26-28kg) than in the free-liquid phase (volatile solid, 5- 7 kg/l) after 90 days of operation. A scaled-up experiment with a polyurethane-added 2.5-1 reactor confirmed the previous results, and no adverse effects such as plugging or channeling due to decreased efficiency was observed even after 4 months of operation.

• 한국유기농업학회지
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• 제21권1호
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• pp.1-18
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• 2013

Animal and crop production systems were integrated on a single farm. This integrated farming system recycled nutrients on the farm. The separation of animal and crop production with the introduction of cheap commercial fertilizers, farms were not used land-applied manure. The on-line manure matching is one of the emerging business in the achievement of recycling and resource recovery. The manure matching actively promotes the reuse and recycling of by-products and manure. This study constructs to manure matching information system to solve the exchange problems between herders and croppers. Manure matching web sites designed. This paper introduces a web-based animal manure matching system. A manure matching service, part of the manure transport, links farmers who produce excess manure with farmers who can use the manure. Farmers registered with the service have requested manure. The manure matching service supports the transport project by linking farmers with excess manure with those farmers who can utilize the manure safely as a nutrient source. The goal of the service is to protect water quality by fostering efficient land application. Benefits to those who use the manure network include reduced disposal costs, lower purchase costs and recycling of manure. The manure matching is based on the principle that 'one persons waste is another person's fertilizer.' It provides a free online matchmaking service for environmentally safe manure recycling management system.

• 한국유기농업학회지
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• 제28권1호
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• pp.69-93
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• 2020

The paper is to compare two villages in Songak-myeon, Asan, Cnungnam Province in Korea. It tries to show how the joint village project, which began with the support of the same external organization, produces different results depending on the internal conditions and circumstances of the village. From the end of the 1990s, Pyeongchon-ri and Sugok-ri started developing villages under the influence of the environmentally friendly farming movement. And subsequent supports were provided by local organizations for the development of the village. However, the village project in Sugok-ri, which focused on economic performance, later turned out to be a failure, and the residents changed to pursue activities for their own economic interests individually. On the other hand, In Pyeongchon-ri, the cooperation among villagers was strengthened in implementing support projects by similar external agencies. In addition, community ties and identity have been strengthened as problems have been solved through cooperation among residents in the process of promoting the village project. Nevertheless, projects undertaken in Pyeongchon-ri for the purpose of increasing economic performance was all failed. Through these findings, the paper asserts that the neo-endogenous development approach utilizing external support on the basis of internal cooperative network among villagers must be a very useful method for rural development in contemporary societies.

• 아시안잔디학회지
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• 제10권3호
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• pp.247-262
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• 1996

In this study, the distribution of dictyostelid cellular slime molds was investigated from F, H and $A_1$ horizon of pinus, oak forests in Mt. Puk'an, Mt. Nam and Mt. Kwanak. The relationship of cellular slime molds with other soil microorganisms and abiotic factors were analyzed. The six species were isolated as follows: Polysphondlium pallidurn, Dictyostelium purpureum, D. mucoroides, D. crassicaule, D. capitatum, D. implicatum. The dominant species in pinus forests was P. pallidum, and in oak forests it was D. macro ides. In Mt. Nam, D. mucoroides and P. pallidum were isolated at only oak forest. The Correlations of slime mold abundance with bacteria were significant. Even though positive correlations of cellular slime molds with actinomycetes or fungi were not significant, correlations between soil microorganisms were analyzed. Correlation coefficients were high in Mt. Kwanak(r=0.5921) and Mt. Nam(r=0.7243) at significant level P<0.01. There were significant correlations between total slime molds and abiotic factors. It supports that cellular slime molds are limited by foods in nature. In low level of pH, water content and organic matter, that community diversity is more affected by bacteria whose organic degradation capacity is regulated by interactions of soil microorgaisms. Key words: Cellular slime molds, Soil microorganisms, Correlations, Abiotic factors.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.211-220
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• 2013

The characteristic fluorescence properties of quercetin (QCT) and apigenin (API) were studied in various $CH_3OH-H_2O$ and $CH_3CN-H_2O$ mixed solvents. The structure of QCT is completely planar. API is not planar at the ground state but becomes nearly planar at the excited state. If the molecules are excited to the $S_1$ state in organic solvents, QCT exhibits no fluorescence due to excited state intramolecular proton transfer (ESIPT) between the -OH and the carbonyl oxygen, but API shows significant fluorescence because ESIPT occurs slowly. If the molecules are excited to the $S_2$ state, both QCT and API exhibit strong $S_2{\rightarrow}S_o$ emission without any dual fluorescence. As the $H_2O$ composition of both solvents increases, the fluorescence intensity decreases rapidly due to the intermolecular hydrogen bonding interaction. The theoretical calculation further supports these results. The change in fluorescence properties as a function of the solvatochromic parameters was also studied.

• Asian Pacific Journal of Cancer Prevention
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• 제15권11호
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• pp.4377-4384
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• 2014

According to the World Health Organization (WHO), 1.37 million people died of lung cancer all around the world in 2008, occupying the first place in all cancer-related deaths. However, this number might be decreased if patients were detected earlier and treated appropriately. Unfortunately, traditional imaging techniques are not sufficiently satisfactory for early detection of lung cancer because of limitations. As one alternative, breath volatile organic compounds (VOCs) may reflect the biochemical status of the body and provide clues to some diseases including lung cancer at early stage. Early detection of lung cancer based on breath analysis is becoming more and more valued because it is non-invasive, sensitive, inexpensive and simple. In this review article, we analyze the limitations of traditional imaging techniques in the early detection of lung cancer, illustrate possible mechanisms of the production of VOCs in cancerous cells, present evidence that supports the detection of such disease using breath analysis, and summarize the advances in the study of E-noses based on gas sensitive sensors. In conclusion, the analysis of breath VOCs is a better choice for the early detection of lung cancer compared to imaging techniques. We recommend a more comprehensive technique that integrates the analysis of VOCs and non-VOCs in breath. In addition, VOCs in urine may also be a trend in research on the early detection of lung cancer.

• 멤브레인
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• 제27권1호
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• pp.1-42
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• 2017

금속유기구조체(metal-organic framework)는 유기물와 무기물로 구성된 나노다공성 결정물질로서 일정한 세공 구조를 가지고 있다. 합성시 유기 리간드의 다양한 선택이 가능함으로 인해 다양한 세공 사이즈와 물리적/화학적 성질들을 나타내는 금속유기구조체가 가능하다. 이러한 특성들로 인해 다공성 금속유기구조체는 새로운 기체분리용 막 재료로 각광받고 있다. 그러나 고품질의 다결정 금속유기구조체막을 재조하는 것은 상당히 어려운 일인데, 이것은 지지체 표면에 금속유기구조체 결정을 자라게 하는 것이 쉽지 않기 때문이다. 지난 이십여 년 동안 마이크로 전자파를 이용한 물질 합성에 대한 연구가 상당히 진행되었는데 특히 마이크로 전자파를 이용하면 전통적인 합성법에 비해 금속유기구조체 분리막을 제조하는 과정에서의 어려움들을 극복할 수 있다. 마이크로 전자파를 이용한 다결정 분리막 제조 공정은 단시간 합성, 복잡한 구조체 합성 및 나노 결정체 합성 등의 장점이 있다. 본 총설에서는 금속유기구조체 분리막 제조 및 기체 분리에 관한 최근 연구성과들을 살펴보고 특히 마이크로 전자파를 이용한 분리막 제조 공정을 중심으로 정리한다.