• Progress in Superconductivity
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• 제6권2호
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• pp.118-123
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• 2005

A low cost YBCO oxide powder was employed as a starting precursor for MOD process. YBCO oxide is advantageous over metal acetates or TFA salts which are popular starting precursors for conventional MOD-TFA process because that YBCO oxide precursor is cheap and easy to control molar ratio. YBCO thin films were prepared by this oxide-precursor-based MOD process and annealing condition was optimized. The YBCO thin film annealed at below $780^{\circ}C$ shows no transport $I_c$ and poor microstructure. Raman spectroscopic study of YBCO thin film indicates that YBCO thin film prepared at below $780^{\circ}C$ contains a number of imperfections such as non-superconducting $BaCuO_2$ phase, cation disorder, etc. However, the YBCO thin film treated at above $800^{\circ}C$ shows improvement in microstructure and current transport properties. This research was supported by a grant from Center for Applied Superconductivity Technology of the 21st Century Frontier R&D Program funded by the Ministry of Science and Technology, Republic of Korea.

• 센서학회지
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• 제27권1호
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• pp.55-58
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• 2018

Low-cost and large-scale fabrication method of nanohole array, which comprises nanoscale voids separated by a few tens to a few hundreds of nanometers, has opened up new possibilities in biomolecular sensing as well as novel frontier optical devices. One of the key aspects of the nanohole array research is how to control the hole size following each specific needs of the hole structure. Here, we report the extensive study on the fine control of the hole size within the range of 500-2500 nm via surface-catalyzed chemical deposition. The initial hole structures were prepared via conventional photo-lithography, and the hole size was decreased to a designed value through the surface-catalyzed chemical reduction of the gold ion on the predefined hole surfaces, by simple dipping of the hole array device into the aqueous solution of gold chloride and hydroxylamine. The final hole size was controlled by adjusting reaction time, and the optimal experimental condition was obtained by doing a series of characterization experiments. The characterization of size-controlled hole array was systematically examined on the image results of optical microscopy, field emission scanning electron microscopy(FESEM), atomic-force microscopy(AFM), and total internal reflection microscopy.

• 한국수산과학회지
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• 제27권5호
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• pp.659-672
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• 1994

진해만의 저서동물 군집에 대해 Sanders(1968)의 희박법(Rarefaction method), Warwick(1986)의 개체수-생물량 비교법(Abundance-Biomass Comparison method), Gray(1979)의 대수-정규분포 응용법 (Log-Normal Distribution method) 및 Frontier(1985)의 순위-빈도 곡선법 (Rank-Frequency Diagram method) 등의 환경 평가 기법을 이용하여 진해만의 오염정도를 평가하였다. 이 방법들 가운데 개체수-생물량 비교법은 오염해역에 개체당 생물량이 큰 이매패류인 Periglypta cf. puerpera와 Macoma tokyoensis와 다모류인 Nectoneanthes multignatha가 출현함으로서 이 방법의 원리에서 요구하는 전제 조건을 잘 반영하지 못하였다. 그러나 나머지 3가지 방법은 진해만의 환경을 잘 반영하고 있었으며, 가장 내만에 위치한 Group-I이 가장 오염된 해역으로 나타났으며 진해만 중앙부 해역인 Group-II도 상당히 오염이 진행된 것으로 나타났다. 그러나 진해만 입구인 Group-III과 VI는 내만 해역에 비해 상대적으로 오염의 영향이 적은 것으로 나타났다. 이러한 방법들 가운데 종별 개체수 자료만을 필요로 하는 대수-정규 분포 응용법이 오염을 평가하는데 가장 편리하고 적합한 것으로 판단되며, 그 밖의 희박법 및 순위-빈도 곡선도 상대적 평가 방법으로는 유익한 수단이 된다. 우리나라의 다른 해역에서의 오염평가도 저서동물의 분포특성을 이용한 이러한 다양한 환경평가 기법을 시도해 보는 것이 바람직할 것으로 생각된다.

• Parasites, Hosts and Diseases
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• 제49권3호
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• pp.221-228
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• 2011

Rodent malaria parasites, such as Plasmodium berghei, are practical and useful model organisms for human malaria research because of their analogies to the human malaria in terms of structure, physiology, and life cycle. Exploiting the available genetic sequence information, we constructed a cDNA library from the erythrocytic stages of P. berghei and analyzed the expressed sequence tag (EST). A total of 10,040 ESTs were generated and assembled into 2,462 clusters. These EST clusters were compared against public protein databases and 48 putative new transcripts, most of which were hypothetical proteins with unknown function, were identified. Genes encoding ribosomal or membrane proteins and purine nucleotide phosphorylases were highly abundant clusters in P. berghei. Protein domain analyses and the Gene Ontology functional categorization revealed translation/protein folding, metabolism, protein degradation, and multiple family of variant antigens to be mainly prevalent. The presently-collected ESTs and its bioinformatic analysis will be useful resources to identify for drug target and vaccine candidates and validate gene predictions of P. berghei.

• Journal of Plant Biotechnology
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• 제37권4호
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• pp.394-399
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• 2010

국내의 GM식물개발과 관련된 R&D사업 중 대표적이라고 할 수 있는 "바이오그린21사업"과 작물유전체기능연구사업단에서 지난 2007년부터 2009년 말 현재까지의 사업성과 중 논문과 동록 된 특허를 분석하여 본 결과 두개의 사업단을 통하여 총 1,212건의 SCI논문과 451건의 비 SCI논문, 그리고 348건의 특허를 등록한 것으로 조사되었다. 이중에서 바이오그린21사업단에서는 6.0%의 SCI 논문, 10.2%의 비SCI논문, 12.6%의 등록된 특허가 그리고 작물유전체기능연사업단의 경우에는 15.7%의 SCI논문, 21.1%의 비SCI 논문, 81.6%의 등록된 특허가 GM식물의 개발과 직접적으로 관련된 것으로 조사되었다. 개발하고자 하는 GM식물의 농업적 특성은 생물학적 스트레스 또는 무생물적 스트레스에 저항성을 갖는 작물 특히 벼와 고추가 가장 많았으나 포장시험까지 진행된 연구 성과는 아직 극히 저조한 것으로 밝혀졌다. 이러한 조사 결과는 국내에서 현재 실험실 또는 온실 단계에서 검정된 초기 단계의 GM식물의 조기상용화를 위하여 보다 많은 연구비가 투자되어야 할 것을 시사하였다.

• Journal of Korea Trade
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• 제25권5호
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• pp.93-109
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• 2021

Purpose - The logistics industry is often featured by its location relevance and industrial concentration. Industrial concentration is conducive to the effective transmission of information by reducing transaction costs and improving transaction efficiency, thus promoting the development of trade. The main purpose of this paper is to measure the spatial total factor productivity and location quotient of the logistics industry in Korea, and to study the impact of the logistics industry efficiency and agglomeration effect on import and export trade in Korea. Design/methodology - First, used the spatial stochastic frontier method to measure the spatial total factor productivity of the logistics industry in Korea, this serves as the efficiency index of the logistics industry in various regions of Korea. Second, calculated the location quotient (LQ) of the logistics industry to measure the industry's concentration degree. Third, employed a spatial econometric model to analyze the impacts of factors such as the efficiency and concentration levels of the logistics industry on import and export trade in Korea. Findings - This study's main findings can be summarized as follows: this study found that the overall efficiency of the logistics industry in Korea needs to be improved, even though it showed an upward trend in all regions of the country; Moreover, the agglomeration level of Korea's logistics industry needs to be improved; Finally, the positive spatial correlation and industrial agglomeration effect of Korea's logistics industry had a positive impact on the country's import and export trade. Originality/value - This study is innovative in terms of research perspective and methods. Most of the previous studies have measured the development level of the logistics industry using the logistics performance index (LPI), Fewer studies have assessed through the spatial total factor productivity and location quotient of the logistics industry in Korea to measure the efficiency index of the logistics industry in various regions of Korea and concentration degree, as well as there was almost no study on the impact of logistics industry efficiency and agglomeration effect on import and export trade in Korea. This study addresses this limitation by analyzing the impacts of the efficiency and agglomeration effect of the logistics industry on import and export trade in Korea.

• Advances in nano research
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• 제10권4호
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• pp.359-371
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• 2021

A tumor immune interaction is a main topic of interest in the last couple of decades because majority of human population suffered by tumor, formed by the abnormal growth of cells and is continuously interacted with the immune system. Because of its wide range of applications, many researchers have modeled this tumor immune interaction in the form of ordinary, delay and fractional order differential equations as the majority of biological models have a long range temporal memory. So in the present work, tumor immune interaction in fractional form provides an excellent tool for the description of memory and hereditary properties of inter and intra cells. So the interaction between effector-cells, tumor cells and interleukin-2 (IL-2) are modeled by using the definition of Caputo fractional order derivative that provides the system with long-time memory and gives extra degree of freedom. Moreover, in order to achieve more efficient computational results of fractional-order system, a discretization process is performed to obtain its discrete counterpart. Furthermore, existence and local stability of fixed points are investigated for discrete model. Moreover, it is proved that two types of bifurcations such as Neimark-Sacker and flip bifurcations are studied. Finally, numerical examples are presented to support our analytical results.

• 한국환경농학회지
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• 제41권2호
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• pp.115-124
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• 2022

BACKGROUND: Methane is a major greenhouse gas attributed to global warming partly contributed by agricultural activities from ruminant fermentation and rice paddy fields. Methanotrophs are microorganisms that utilize methane. Their unique metabolic lifestyle is enabled by enzymes known as methane monooxygenases (MMOs) catalyzing the oxidation of methane to methanol. Rice absorbs, transports, and releases methane directly from soil water to its stems and the micropores and stomata of the plant epidermis. Methylobacterium species associated with rice are dependent on their host for metabolic substrates including methane. METHODS AND RESULTS: Methylobacterium spp. isolated from rice were evaluated for methane oxidation activities and screened for the presence of sMMO mmoC genes. Qualitatively, the soluble methane monooxygenase (sMMO) activities of the selected strains of Methylobacterium spp. were confirmed by the naphthalene oxidation assay. Quantitatively, the sMMO activity ranged from 41.3 to 159.4 nmol min^-1 mg of protein^-1. PCR-based amplification and sequencing confirmed the presence and identity of 314 bp size fragment of the mmoC gene showing over 97% similarity to the CBMB27 mmoC gene indicating that Methylobacterium strains belong to a similar group. CONCLUSION(S): Selected Methylobacterium spp. contained the sMMO mmoC gene and possessed methane oxidation activity. As the putative methane oxidizing strains were isolated from rice and have PGP properties, they could be used to simultaneously reduce paddy field methane emission and promote rice growth.

• Advances in aircraft and spacecraft science
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• 제9권3호
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• pp.195-215
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• 2022

The increasing interest in CubeSat platforms ant their capability of enlarging the frontier of possible missions impose technology improvements. Miniaturized electrical propulsion (EP) systems enable new mission for multi-unit CubeSats (6U+). While electric propulsion systems have achieved important level of knowledge at equipment level, the investigation of the mutual impact between EP system and CubeSat technology at system level can provide a decisive improvement for both the technologies. The interaction between CubeSat and EP system should be assessed in terms of electromagnetic emissions (both radiated and conducted), thermal gradients, high electrical power management, surface chemical deposition, and quick and reliable data exchanges. This paper shows how a versatile CubeSat Test Platform (CTP), together with standardized procedures and specialized facilities enable the acquisition fundamental and unprecedented information. Measurements can be taken both by specific ground support equipment placed inside the vacuum facility and by dedicated sensors and subsystems installed on the CTP, providing a completely new set of data never obtained before. CTP is constituted of a 6U primary structure hosting the EP system, representative CubeSat avionics and batteries. For the first test campaign, CTP hosts the ambipolar plasma propulsion system, called Regulus and developed by T4I. After the integration and the functional test in laboratory environment, CTP + Regulus performed a Test campaign in relevant environment in the vacuum chamber at CISAS, University of Padua. This paper is focused on the test campaign description and the main results achieved at different power levels for different duration of the firings.

• 분석과학
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• 제20권4호
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• pp.339-346
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• 2007

높은 염색성과 형광성을 나타내는 ninhydrin 유도체를 탐색하기 위하여 잠재지문 검출제로서 ninhydrin 유도체들과 glycine 분자와의 반응성에 관한 분자 홀로그래피적인 HQSPR 모델을 유도하고 정량적으로 검토하였다. Ninhydrin의 반응성은 ${\varepsilon}LUMO$ 에너지가 중요한 요인이었으며, ninhydrin 유도체들과 glycine 분자 사이의 경계분자궤도(FMO) 상호작용으로부터 궤도조절반응에 의한 친핵성 반응이 전하조절반응에 의한 친전자성 반응보다 우세하였다. 기여도 분석결과, benzo 고리상 강한 전자끌게로서 meta-치환체가 ninhydrin의 반응성을 증가시켰으며 HQSPR 및 QSPR 모델에 의하여 5,6-dinitroninhydrin 분자는 비 치환체보다 3배 이상의 반응성을 향상시킬것으로 예측되었다.