• 대한기계학회논문집
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• 제11권1호
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• pp.105-109
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• 1987

본 연구는 열교환기의 설치 및 사용목적에 따라 전열관내유동이 경사류가 될 때 특히 자연순환(2*$10^{6}$＜Gr＜15*$10^{6}$)의 경우와 강제순환(3,000＜Re＜ 40,000)의 경우에 대해서 열전달특성과 유동마찰에 의한 손질을 규명하는데 있다. 사용되는 관은 평골관과 ribbed관이며 관경사각을 수평면에 대하여 0˚,22.5˚,45˚, 90˚로 변화시켰다.

• 생명과학회지
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• 제34권2호
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• pp.86-93
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• 2024

플라스미드의 복제는 엄격하게 조절되어야 하기 때문에 일반적으로 rolling circle 복제를 수행하는 플라스미드들은 복제 개시인자인 RepB는 전사 및 번역 수준에서 엄격하게 조절되어 일정한 copy number를 유지한다. 플라스미드 pJB01에는 단일 오페론으로 구성된 세 개의 orfs (copA, repB, repC 또는 repABC)가 포함되어 있다. 아미노산 서열 분석에서 pJB01 CopA는 다른 플라스미드의 복제 수 조절 단백질로서 Cops와 상동성을 보였다. pMV158의 CopG와 비교할 때, CopA는 플라스미드의 일반화된 억제자의 모티브로 알려진 RHH (ribbon-helix-helix)를 형성하는 것으로 추정된다. gel mobility shift assay 결과 정제된 융합 단백질이 repABC 오페론의 operator 영역에 결합하는 것으로 나타났다. 전사 수준에 대한 CopA의 기능적 역할을 조사하기 위해 CopA R16M, K26R 및 E50V와 같은 세 개의 포인트 돌연변이가 CopA의 코딩 프레임에서 구성되었다. CopA R16M, K26R 및 E50V 돌연변이의 repABC mRNA 수준은 CopA wt보다 각각 1.84, 1.78 및 2.86배 증가했다. 또한 세 개의 CopA 유전자의 돌연변이로 인한 복제 수도 CopA wt보다 각각 1.86, 1.68 및 2.89배 증가했다. 이러한 결과는 CopA가 전사 억제자이며 복제 개시자로서 repABC mRNA 및 RepB 단백질 수를 감소시킴으로써 pJB01의 복제 수를 감소시키는 것으로 제의된다.

• 한국전자파학회논문지
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• 제9권6호
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• pp.776-787
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• 1998

835 MHz에서 동작하는 셀룰라 휴대폰에 의한 인체 두부내의 1 g 및 10 g 평균 비홉수율(specific absorption rate, SAR)을 해석한다. 사용되는 수치방법은 총 전자기장 유한차분 시간영역(finite-difference time-domain, FDTD) 기법이다. 전화기는 도체박스, 플라스틱 케이스 그리고 모노폴 안테나와 나선형 안테나 로 구성된 whip 안테나로 모의되었다. 공간 정밀도 3 mm의 이산적 인체두부 모델은 MRI(Magnetic Resonance Imaging), CT(computerized tomography) 그리고 해부학적 이미지에 기초한 것이다 안테나를 뽑은 전화기와 접은 전화기에 대한 근역장 및 원역장 복사 패턴이 분석되었다. SAR 평가를 위한 재현성 있는 기법을 제공하기 위해 조직내의 1 g 또는 10 g의 질량을 갖는 체적을 취하는 두 가지 방법을 제안하고 비교 한다.

• 설비공학논문집
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• 제14권3호
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• pp.231-239
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• 2002

Experiments on the single phase cooling heat transfer and pressure drop with microfin tubes were performed using water as a test fluid. Experimental data were obtained in the range of Reynolds number 3000 ~40000 and Prandtl number 4-6. The data of microfin tubes presented the characteristics of rough surface tube in pressure drop and heat transfer Experimental data were compared with the heat transfer and friction factor correlations of smooth tubes. Heat transfer enhancements of microfin tubes were lower than pressure drop penalty factors. The helix angle is more significant parameter in both of the pressure drop and heat transfer than the relative roughness. The correlations of Nusselt number and friction factor were suggested for the tested microfin tubes. Maximum deviations between correlations and experimental data were within $\pm15$% for Nusselt number and $\pm10$% for friction factor.

• Journal of Contemporary Eastern Asia
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• 제12권1호
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• pp.81-93
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• 2013

Over the past several decades, educational systems in many parts of the world have undergone manifold changes that have significantly affected the work environment of educators. Among other negative impacts of the globalized reforms in higher education has been the increasing prevalence of workplace bullying. The purpose of this research note is to serve different purposes: (1) examine the causes behind the changing landscape of higher education; (2) discuss previous and current research on workplace bullying; (3) introduce the methodology of the Taiwan Higher Education Faculty Survey (THEFS); (4) outline its anticipated outcome.

• Journal of Contemporary Eastern Asia
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• 제13권2호
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• pp.3-14
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• 2014

Online communities are an important source of electronic-word-of-mouth (eWOM), however few studies have examined these types of messages within the Middle Eastern context. This study focuses on Kuwaiti women as members of an online beauty forum; previous work has suggested a mediating effect of gender with women being more likely to trust and follow-up word-of-mouth with a purchase. A conceptual model, based on existing theoretical contributions, provides the basis of a coding framework for the message characteristics that influence members' eWOM adoption. A sub-set of the analysis is presented: 218 threads (1820 messages, coded into 6702 units) illustrating cases where eWOM was adopted and thereby demonstrating continuance intention with members returning to the forum. Content analysis revealed the prevalence of emotional aspects in messages, coded into a new category of 'community bonding'. Findings show that emotion expressed in messages is as influential and important as cognitive aspects of argument quality.

• 한국생산제조학회지
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• 제26권2호
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• pp.257-261
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• 2017

Drilling file is medical mini-drill which is made of Ni-Ti material and has tapered shape. It's for removing teeth nervine which helps the endodontic treatment. All files, saled at domestic market, are imported from U.S. and Europe. Also they have low manufacturing efficiency and high price because it is made by universal 5 axis CNC grinding machine. To solve these problem, 3 axis CNC table, controllable tilting angle spindle and helix angle moving table are devised. To confirm divised CNC grinding machine's manufacturing accuracy, conveying amount and finish product size measurement expreiment has been practiced. Also to automate all manufacturing processes, automatic mechanism is designed.

• Genomics & Informatics
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• 제9권2호
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• pp.79-84
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• 2011

Two initial models of cold-adapted lipase PsLip1 have been constructed, based on homology with the bacterial lipases Chromobacterium viscosum (CvLip) and Pseudomonas cepacia (PcLip), whose X-ray structures have been solved and refined to high resolution. The mature polypeptide chains of these lipases have 84% similarity. The models of Mod1 and Mod2 have been compared with the tertiary structures of CvLip and PcLip, respectively, and analyzed in terms of stabilizing interactions. Several structural aspects that are believed to contribute to protein stability have been compared: the number of conserved salt bridges, aromatic interactions, hydrogen bonds, helix capping, and disulfide bridges. The 3-dimensional structural model of PsLip1 has been constructed in order to elucidate the structural reasons for the decreased thermostability of the enzyme in comparison with its mesophilic counterparts.

• Bulletin of the Korean Chemical Society
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• 제18권1호
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• pp.50-56
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• 1997

The mode of action of mastoparan B, an antimicrobial cationic tetradecapeptide amide isolated from the hornet Vespa basalis, toward phospholipid bilayers was studied with synthetic mastoparan B and its analogs with individual Ala instead of hydrophobic amino acids (1-Ile, 3-Leu, 6-Leu, 7-Val, 9-Trp, 13-Val, 14-Leu) in mastoparan B. Mastoparan B and its analogs were synthesized by the solid-phase method. Circular dichroism spectra showed that mastoparan B and its analogs adopted an unordered structure in buffer solution. In the presence of neutral and acidic liposomes, most of the peptides took an α-helical structure. The calcein leakage experiment indicated that mastoparan B interacted strongly with neutral and acidic lipid bilayers than its analogs. Mastoparan B also showed a more or less highly antimicrobial activity and hemolytic activity for human erythrocytes than its analogs. These results indicate that the hydrophobic face in the amphipathic α-helix of mastoparan B critically affect biological activity and helical contents.

• Journal of Contemporary Eastern Asia
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• 제17권2호
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• pp.237-253
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• 2018

In order to understand China's internet governance, this paper examined 1,931 Internet policies of China by bibliometric techniques. Specifically, the bibliometric techniques include simple document counting, co-word analysis, collaboration network analysis and citation analysis. The findings include: (1) China's Internet legislations mainly emphasized e-commerce and Internet governance, and, to some extent, neglected personal data protection; (2) China's Internet is under intensive multiple regulatory controls by central government. A large number of government agencies are involved in Internet policy-making. The Propaganda Department of the Central Committee of the Communist Party of China and the State Information Leading Group of the State Council, enforced fewer policy documents, but occupy higher positions in the Internet governance hierarchy; (3) China's Internet legislation system is primarily composed of industry-specific administrative rules, rather than laws or administrative regulations. Nevertheless, laws and administrative regulations received significantly more citations owing to their superior force. This paper also discussed current gaps in China's internet governance and how the country's internet policies are situated in the broader global context.