• 미생물학회지
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• 제33권4호
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• pp.242-246
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• 1997

Synechococcus sp. cyanophage의 SDS-PAGE 수행 결과 구조단백질은 두 개의 major protein(97 kDa, 52 kDa)과 최소 일곱 개의 minor protein(70 kDa, 65 kDa, 60 kDa, 40 kDa, 35 kDa, 28 kDa, 6 kDa)으로 구성되어 있는 것으로 나타났다. Subunit들은 서로 disulfide bond로 연결되어 있지는 않지만 비공유적 결합으로 multimer를 형성하여 phage particle을 구성하고 있는 것으로 보인다. 또한 heat-killed Micrococcus luteus cell을 기질로 이용한 renaturing SDS-PAGE 방법으로 phage particle내의 세포벽 분해능을 살표본 결과 52 kDa 부근에서 세포벽 분해활성이 발견되었다. 이러한 세포벽 분해활성은 최적 pH가 9~10 사이이며 EDTA에 대한 낮은 저해를 나타내었다.

• 한국산업융합학회 논문집
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• 제23권2_1호
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• pp.115-124
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• 2020

In wireless power transfer (WPT) system, the conventional compensation topologies only can provide a constant current (CC) or constant voltage (CV) output under their resonant conditions. It is difficult to meet the CC and CV hybrid charging requirements without any other schemes. In this study, a switching hybrid topology (SHT) is proposed for CC and CV electric vehicle (EV) battery charging. By utilizing an additional capacitor and two AC switches (ACSs), a double-side LCC (DS-LCC) and an inductor and double capacitors-series (LCC-S) topologies are combined. According to the specified CC and CV charging profile, the CC and CV charging modes can be flexibly converted by the two additional ACSs. In addition, zero phase angle (ZPA) also can be achieved in both charging modes. In this method, because the operating frequency is fixed, without using PWM control, and only a small number of devices are added, it has the benefits of low-cost, easy-controllability and high efficiency. A 3.3-kW experimental prototype is configured to verify the proposed switching hybrid charger. The maximum DC efficiencies (at 3.3-kW) of the proposed SHT is 92.58%.

• 한국산학기술학회논문지
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• 제17권10호
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• pp.13-20
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• 2016

교량은 지속적인 규모의 증가와 노후화의 확대로 인해 전산화된 관리 체계가 요구되었다. 국내외 교량관리시스템(Bridge Management System; BMS) 개발 동향 및 기능의 비교, 고찰을 통해 생애주기 관리가 가능한 ICT (Information and Communication Technology) 기반 교량 관리 체계를 제안하였다. BMS는 인터넷과 모바일이 결합된 운영 체계에 GIS 기능과 객체 기반 정보 관리 체계를 바탕으로 개발되었다. BMS는 교량의 생애주기 동안 발생되는 모든 정보의 객체 기반 정보화를 수행하여, 생애주기 성능 변화와 소요 예산의 추정을 바탕으로 중장기 관리 전략과 단기 관리 계획의 수립을 지원한다. 실제 공용중인 교량 약 6천 개소에 대한 생애주기 관리 전략 수립을 통해 의사 결정 지원을 위한 유용한 지식 정보를 도출하였다. 전국의 모든 도로교량에 적용 가능하도록 개발된 BMS는 정확한 이력 관리를 통한 성능 유지, 합리적인 예산 관리를 통한 비용 절감, 현장 정보 수집의 편의성 및 신뢰성 증진을 위해 실제적, 실용적으로 활용될 수 있을 것으로 판단된다.

• Nuclear Engineering and Technology
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• 제42권6호
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• pp.620-635
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• 2010

In this paper we describe current activities on the project Multi-Scale Modeling and Analysis of convective boiling (MSMA), conducted jointly by the Paul Scherrer Institute (PSI) and the Swiss Nuclear Utilities (Swissnuclear). The long-term aim of the MSMA project is to formulate improved closure laws for Computational Fluid Dynamics (CFD) simulations for prediction of convective boiling and eventually of the Critical Heat Flux (CHF). As boiling is controlled by the competition of numerous phenomena at various length and time scales, a multi-scale approach is employed to tackle the problem at different scales. In the MSMA project, the scales on which we focus range from the CFD scale (macro-scale), bubble size scale (meso-scale), liquid micro-layer and triple interline scale (micro-scale), and molecular scale (nano-scale). The current focus of the project is on micro- and meso-scales modeling. The numerical framework comprises a highly efficient, parallel DNS solver, the PSI-BOIL code. The code has incorporated an Immersed Boundary Method (IBM) to tackle complex geometries. For simulation of meso-scales (bubbles), we use the Constrained Interpolation Profile method: Conservative Semi-Lagrangian $2^{nd}$ order (CIP-CSL2). The phase change is described either by applying conventional jump conditions at the interface, or by using the Phase Field (PF) approach. In this work, we present selected results for flows in complex geometry using the IBM, selected bubbly flow simulations using the CIP-CSL2 method and results for phase change using the PF approach. In the subsequent stage of the project, the importance of effects of nano-scale processes on the global boiling heat transfer will be evaluated. To validate the models, more experimental information will be needed in the future, so it is expected that the MSMA project will become the seed for a long-term, combined theoretical and experimental program.

• 한국자원식물학회지
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• 제31권6호
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• pp.641-651
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• 2018

Floral scents and metabolites from cut flowers of 14 peony cultivars (Paeonia lactiflora Pall.) were analyzed to discriminate different cultivars and to compare the Korean cultivar with the other cut peonies imported to Korea using electronic nose (E-nose) and Fourier transform infrared (FT-IR) spectroscopy combined with multivariate analysis, respectively. Principal component analysis (PCA) and discriminant function analysis (DFA) dendrogram of peony floral scents were not precisely same but there were 3 groups including same cultivars. PCA and partial least squares-discriminant analysis (PLS-DA) dendrograms of peony metabolites showed that different cut peony cultivars were clustered into two major groups including same cultivars. Fragrance pattern of Korean 'Taebaek' was classified to same group with 'Jubilee' on the PCA and DFA results and its metabolite pattern was clearly discriminated by the PCA and PLS-DA compared to the other cultivars. These results show that the 14 peony cut flowers could be discriminated corresponding to their chemical relationship and the metabolic profile of Korean 'Taebaek' has distinctive characteristics. Furthermore, we suggest that these results could be used as the preliminary data for breeding new cut peony cultivars and for improving the availability of Korean cut peony in cosmetic industry.

• Geomechanics and Engineering
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• 제19권1호
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• pp.11-20
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• 2019

The use of electrokinetic dissipation method to study the fluid flow law in micro-pores is of great significance to reservoir rock microfluidics. In this paper, the micro-capillary theory was combined with the coupling model of the seepage field and the current field under the excitation of the harmonic signal, and the coupling theory of the electrokinetic effect under the first-order approximation condition was derived. The dissipation equation of electrokinetic dissipation and viscous resistance dissipation and its solution were established by using Green's function method. The physical and mathematical models for the electrokinetic dissipation of reservoir rocks were constructed. The microscopic mechanism of the electrokinetic dissipation of reservoir rock were theoretically clarified. The influencing factors of the electrokinetic dissipation frequency of the reservoir rock were analyzed quantitatively. The results show that the electrokinetic effect transforms the fluid flow profile in the pores of the reservoir from parabolic to wavy; under low-frequency conditions, the apparent viscosity coefficient is greater that one and is basically unchanged. The apparent viscosity coefficient gradually approaches 1 as the frequency increases further. The viscous resistance dissipation is two orders of magnitude higher than the electrokinetic effect dissipation. When the concentration of the electrolyte exceeds 0.1mol/L, the electrokinetic dissipation can be neglected, while for the electrolyte solution (<$10^{-2}M$) in low concentration, the electrokinetic dissipation is very significant and cannot be ignored.

• 한국항행학회논문지
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• 제25권1호
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• pp.17-28
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• 2021

최근 많은 나라 대도시의 교통체증과 더불어 지구온난화로 인해 차세대 친환경 교통수단인 eVTOL이 각광받고 있다. 본 연구에서는 많은 유형의 eVTOL 중 고정로터와 틸트로터가 결합된 복합형 eVTOL인 현대자동차 S-A1의 외부형상을 벤치마킹하여 역설계 기법을 활용하여 기본 형상을 구현하였다. CATIA를 사용하여 기본 형상을 구현한 후 항공기 설계 및 공력해석 프로그램인 OpenVSP, XFLR5를 사용하여 공력해석을 수행하였고 비교분석을 통해 익형과 붙임각, 상/하반각을 선택한 후 항공기 표면적 및 항력, 양력을 계산하였다. 또한 주어진 임무형상을 수행하기 위한 필요 동력을 산정하고 추정식과 자료조사를 통하여 구성품과 전체 무게를 추정하였다.

• Journal of Korean Neurosurgical Society
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• 제65권4호
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• pp.523-530
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• 2022

Objective : To evaluate the safety and efficacy of an overlapped stenting-assisted coiling technique in treating vertebral artery dissecting aneurysm (VADA) via Low-profile Visualized Intraluminal Support (LVIS) stent-within-Neuroform EZ stent. Methods : From January 2017 to June 2019, 18 consecutive patients with VADAs (ruptured : unruptured=5 : 13) were treated with the overlapping stents assisted-coiling technique in our center. The overlapping manner was a Neuroform EZ stent being deployed first, followed by LVIS stents placement using the 'shelf' technique. The patients' clinical characteristics, technical feasibility and safety, and immediate and follow-up angiographic results were retrospectively reviewed. Results : Seventeen (94.4%) procedures were technically successful with an exact deployment of the stents and patent parent or perforator arteries. The immediate angiographies after procedure confirmed Raymond class I, II, and III occlusion of VADAs were in 12 (66.7%), two (11.1%), and four cases (22.2%), respectively. Post-procedural complications developed in one patient (5.6%) with minor brainstem infarctions, which resulted from an in-stent thrombosis during the procedure. Angiographic follow-up at 5.7 months (range 3 to 9 months) demonstrated Raymond class I and II occlusion were in all cases (100%). The modified Rankin Scale scores at 21.3 months (range 15 to 42 months) 0-2 in 17 cases (94.4%) and three in one case (5.6%). Conclusion : Overlapping stents via LVIS stent-within-Neuroform EZ stent combined with coiling is safe and effective for patients with VADA in the midterm results.

• Animal Bioscience
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• 제35권8호
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• pp.1162-1173
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• 2022

Objective: This study aimed to investigate the fermentation profiles, bacterial community and predicted metabolic characteristics of Sudangrass (Sorghum sudanense Stapf.) during ensiling. Methods: First-cutting Sudangrass was harvested at the vegetative stage and ensiled in laboratory-scale silos (1 L capacity). Triplicate silos were sampled after 1, 3, 7, 15, 30, and 60 days of ensiling, respectively. The bacterial communities on day 3 and 60 were assessed through high-throughput sequencing technology, and 16S rRNA-gene predicted functional profiles were analyzed according to the Kyoto encyclopedia of genes and genomes using Tax4Fun. Results: The Sudangrass silages showed good fermentation quality, indicated by higher lactic acid contents, and lower pH, butyric acid and ammonia nitrogen contents. The dominant genus Lactococcus on day 3 was replaced by Lactobacillus on day 60. The metabolism of amino acid, energy, cofactors and vitamins was restricted, and metabolism of nucleotide and carbohydrate was promoted after ensiling. The 1-phosphofructokinase and pyruvate kinase of bacterial community seemed to play important roles in stimulating the lactic acid fermentation, and the promotion of arginine deiminase could help lactic acid bacteria to tolerate the acidic environment. Conclusion: High-throughput sequencing technology combined with 16S rRNA gene-predicted functional analyses revealed the differences during the early and late stages of Sudangrass ensiling not only for distinct bacterial community but also for specific functional metabolites. The results could provide a comprehensive insight into bacterial community and metabolic characteristics to further improve the silage quality.

• 한국항행학회논문지
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• 제26권5호
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• pp.331-337
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• 2022

색 분산과 비선형 Kerr 효과에 의한 신호 왜곡을 보상하는 광학 위상 공액과 결합된 분산 제어 링크에서 광섬유의 길이가 보상의 효율성을 결정하는 주요 요인이다. 분산 제어 링크는 표준 단일 모드 광섬유와 분산 보상 광섬유가 배열된 여러 개의 중계 구간으로 구성된다. 본 논문에서는 광 위상 공액기 (OPC; optical phase conjugator)를 중심으로 전반 링크와 후반 링크에서 각각 서로 다른 한 종류의 광섬유들의 길이 변화만으로 RDPS (residual dispersion per span)에 변화를 주는 링크에서의 보상 효과를 살펴보았다. 누적 분산 프로파일이 OPC를 중심으로 원점 대칭이 되면서 동시에 전반 링크에서는 누적 분산량은 모두 양으로, 반면 후반 링크에서는 누적 분산량은 모두 음으로 분포시키는 분산 제어 링크가 960 Gb/s 파장 분할 다중 신호에 대해 가장 우수한 보상이 얻어지는 것을 확인하였다.