• 한국생산제조학회지
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• 제26권3호
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• pp.306-312
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• 2017

Press rolls are constantly exposed to physical and heat stresses on their surface and are prone to crack, bruise, and spall if the accumulated stress goes beyond the critical point. Such surface phenomenon can cause them to lose their functionality and eventually lead to a halted production line. Eddy current testing can be considered a useful method to investigate the surface of the roll. The method involves the application of a high intensity magnetic field onto the surface of the roll, and thereby finding any early stage of possible defects. When the method was applied for roll inspection, the cross section of the sensor was regulated as per the overall testing speed. A smaller cross sectional area implied a better resolution but a longer testing time. In this paper, a convenient method to increase both overall system resolution and inspection speed of eddy current roll inspection is suggested by using a devised array sensor structure.

• Journal of Welding and Joining
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• 제29권1호
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• pp.107-114
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• 2011

CP steel was developed to reduce the weight and increase the strength of car body. When it was welded using state-of-the-art disk laser welding, the effected of boron on the microstructure and hardness were investigated. Welding power was fixed at 3.5kW and welding speeds were 4,8 and 12m/min. Full penetration occurred in welding speed of 12m/min and weld bead was almost unchanged with boron contents. But the welding speed increased, the upper and lower bead were narrowed. In a welding speed of more than 8m/min, underfill defects were formed on the bead bottom. The hardness of weld zone was somewhat fluctuation in fusion zone and HAZ showed the highest hardness values. The hardness of each region showed little change with the boron contents, and softening phenomenon occurred in the HAZ near the base metal regardless of the boron contents.

• 복식
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• 제53권3호
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• pp.13-31
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• 2003

The purpose of this study is to analyze the formative style and aesthetic value of contemporary subcultural style with the understanding of characteristics of subcultural style in the sociocultural context. As for the research methodology, literary survey has been performed to study the concept and the history of subcultural styles from 1940s to 1980s. In addition, demonstrative studies on aesthetic images have been carried out through the analysis of pictures and photographs in order to categorize the subcultural styles since 1990s. In this study, subcultural styles since 1990s have been illustrated through the socio-cultural grounds. which are diversity of street culture, diffusion of moss culture or bubble-up phenomenon, pursuit of anti-social ideology among intellectual heads, club Cultures in the form of kitsch and pastiche and communal thinking as collective harmony. With the socio-cultural context examined above, subcultural styles in the contemporary fashion are categorized and deduced following aesthetic values ; Drag and Club style as the tendency of surrealists or artificial hedonists, Urban military style and Cyberpunks as pursuit of Bionic being, Sports casual style based upon, the pursuit of comfort and freedom, Vintage style and Retro dressing represented by the spirit of DIY (no It Yourself), Ecology style of New conservatives, and Mysticism style as the fusion of technology and shamanism (Technoshamanism).

• 한국문헌정보학회지
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• 제28권
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• pp.135-165
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• 1995

When the unification process was established, West German librarians formed a commission for all library and information sectors. After legal unification, the committee formed 6 Arbeitsgruppe(AG) to develop library and information policies for the country. This was designed specially to elevate the level of the East German library system to the West German standard. The first AG concerns the public libraries. The second AG focuses on the education system for library and information specialists. The third AG examines the academic libraries. The fourth AG reviews the regional and national library services and the central organization. The fifth AG explores library and information techniques. The sixth and final AG inspects the legal problem of libraries. Each AG consists of specialists from both East and West German library systems who are experts in their particular subject area. The committee has general meetings to determine the best direction for the nation's library system. Common knowledge indicates this unification was based on economical amalgamation(fusion) from East Germany to West Germany. The unification resulted in the library and information recommendations tending to favor the more advanced West German policies. In this process there are a number of subtle ideological and psychological problems. If before the separation they had developed their library system as one entity, they could overcome the current differences. with much less confusion. In this political phenomenon we can learn that cultural unification needs more time than political unification.

• Mycobiology
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• 제39권4호
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• pp.235-242
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• 2011

In contrast to the nuclear genome, the mitochondrial genome does not follow Mendelian laws of inheritance. The nuclear genome of meiotic progeny comes from the recombination of both parental genomes, whereas the meiotic progeny could inherit mitochondria from one, the other, or both parents. In fact, one fascinating phenomenon is that mitochondrial DNA in the majority of eukaryotes is inherited from only one particular parent. Typically, such unidirectional and uniparental inheritance of mitochondrial DNA can be explained by the size of the gametes involved in mating, with the larger gamete contributing towards mitochondrial DNA inheritance. However, in the human fungal pathogen Cryptococcus neoformans, bisexual mating involves the fusion of two isogamous cells of mating type (MAT) a and MAT${\alpha}$, yet the mitochondrial DNA is inherited predominantly from the MATa parent. Although the exact mechanism underlying such uniparental mitochondrial inheritance in this fungus is still unclear, various hypotheses have been proposed. Elucidating the mechanism of mitochondrial inheritance in this clinically important and genetically amenable eukaryotic microbe will yield insights into general mechanisms that are likely conserved in higher eukaryotes. In this review, we highlight studies on Cryptococcus mitochondrial inheritance and point out some important questions that need to be addressed in the future.

• 한국재료학회지
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• 제31권8호
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• pp.465-470
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• 2021

Deuterium is a crucial clean energy source required for nuclear fusion and is a future resource needed in various industries and scientific fields. However, it is not easy to enrich deuterium because the proportion of deuterium in the hydrogen mixture is scarce, at approximately 0.016 %. Furthermore, the physical and chemical properties of the hydrogen mixture and deuterium are very similar. Therefore, the efficient separation of deuterium from hydrogen mixtures is often a significant challenge when using modern separation technologies. Recently, to effectively separate deuterium, studies utilizing the 'Kinetic Quantum Sieving Effect (KQS)' of porous materials are increasing. Therefore, in this review, two different strategies have been discussed for improving KQS efficiency for hydrogen isotope separation performance using nanoporous materials. One is the gating effect, which precisely controls the aperture locally by adjusting the temperature and pressure. The second is the breathing phenomenon, utilizing the volume change of the structure from closed system to open system. It has been reported that efficient hydrogen isotope separation is possible using these two methods, and each of these effects is described in detail in this review. In addition, a specific-isotope responsive system (e.g., 2nd breathing effect in MIL-53) has recently been discovered and is described here as well.

• 생명과학회지
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• 제9권2호
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• pp.169-175
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• 1999

Salmonella typhimurum은 생활사 동안에 다양한 환경과 접하게 된다. S. typhimurium은 오염된 웅덩이에서 숙주의 phgolysosome에 이르기까지 생태계에 널리 분포하면서 산성 스트레스를 경험하며 또한 생존할 수 있다. Salmonella 이와 같은 산저항능은 Acid Tolerance Response (ATR)에 의해 획득된다. 약산의 pH에 적응된 S. typhimurium은 낮은 pH 영역에서 생존할 수 있는 일종의 대항능을 갖게되며, 이런 생존 능력은 복잡한 유전적 유도현상 결과로 해석된다. Salmonella 있어서 ATR은 RpoS 의존적 그리고 RpoS 비의존적 현상으로 구분되며, 특히 혐기적 조건(5% $CO_2$, 5% H$_2$, 90% $N_2$)에서 rpoS$\Omega$Ap는 UK1과 동일한 ATR을 나타내어, 혐기적 조건의 ATR은 RpoS 비의존적인 것으로 판명되었다. P22와 MudJ (Km, lacZ)를 이용한 gene fusion기법과 sodium acetate (pH4.5)를 이용한 돌연변이체 분리방법을 병행하여 산민감성의 형질을 나타내는 LE487 aatA::MudJ를 얻었다. antA 는 Salmonella의 유전자 지도상에서 12min에 위치하는 것으로 조사되었다. antA는 혐기적 조건(5% $CO_2$, 5% H$_2$, 90% $N_2$)하의 pH4.3 조건에서 야생형 Salmonella 비해서 매우 높은 산민감성을 보여주었다. 그러므로 antA는 혐기적 ATR에 있어서 산적응 기전에 관여하는 중요한 유전자로 확인되었다.

• 한국산학기술학회논문지
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• 제21권1호
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• pp.760-767
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• 2020

발전용 수력플랜트 분야는 기후변화 및 에너지 확보를 고려해 향후 지속적인 성장이 전망된다. 수력발전설비는 항상 수충격에 의한 위험에 노출되어 있고, 이에 대한 안정성 확보는 매우 중요하다. 수충격 현상은 밸브의 개도 조정이나 펌프와 터빈의 기동 및 정지 시 관로설비 전반에 걸쳐 발생하며, 예기치 못한 긴급 상황 시에는 더욱 현저하게 나타난다. 이와 같은 수충격에 대한 발전설비의 안정성 검토를 위해 본 연구에서는 수충격 발생 메커니즘을 반영된 특성선법을 적용한 수치해석기법(MOC-FDM: Method of Characteristic-Finite Dimensional Method, 이하 MOC-FDM)을 이용하여 전산수치 모형을 개발하였다. 개발모형은 발전설비의 주요시설인 저수지, 관로, 밸브, 펌프 등 경계조건을 반영하였고 가상시나리오 case를 적용하여 개발모형을 이용한 수치모의를 수행하였다. 개발모형 해석결과의 검증을 위해 발전설비의 주요 지점에서의 해석결과를 각각 제시하였다. 각 case 별 수충격 현상이 양호하게 재현되었으며, 상용모델의 수치해석결과와 비교분석 결과가 거의 유사하게 나타나 개발모형의 신뢰성을 확인하였다. 본 연구에서 제시된 전산수치 모델은 수력발전설비의 운영 중 발생할 수 있는 비정상상태의 유체 거동을 정교하게 예측함으로써 설비의 안정성 검토를 위한 유용한 도구로 활용될 수 있을 것으로 판단된다.

• 한국측량학회지
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• 제36권4호
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• pp.305-316
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• 2018

우리나라의 도시화 비율이 증가함에 따라 도시열섬으로 인한 도시 열 환경의 중요성이 증대되고 있다. 본 연구에서는 2012년에 출범하여 급속도로 발전을 이룬 세종특별자치시의 도시 열 환경 분석을 위해 열섬포텐셜을 이용하였다. 우선 도심지의 비율 및 변화율을 분석하기 위해 Landsat-8 OLI/TIRS 위성영상을 기반으로 연구지역의 시계열 토지피복도(2013년~2015년, 2017년)를 생성하였다. 그리고 취득된 위성영상에서 제공하는 두 가지 열적외선 밴드에서 산출된 밝기온도와 자동기상관측망 자료와의 정확도 평가를 통해 연구에 활용할 밴드를 선정하였다. 선정된 밴드와 지표면 방사율을 고려하여 지표면온도를 산출하였으며, 이를 기반으로 산출된 열섬포텐셜 변화분석을 수행하였다. 분석결과, 연구지역의 행정구역별 도심지 변화율이 크게 관측되는 지역의 지표면온도는 주변지역 보다 $3^{\circ}C{\sim}4^{\circ}C$ 높고, 열섬포텐셜 또한 $4^{\circ}C{\sim}5^{\circ}C$ 높게 관측되었다. 하지만 도심지 변화율이 크고 녹지의 비율이 높은 지역에서는 열섬현상이 완화되는 경향을 보였다. 이를 통해 면적대비 도심지가 차지하는 비율이 높아지면 열섬을 유발할 가능성이 증가하지만 녹지를 통해 열섬을 완화 시킬 수 있다는 것을 알 수 있었다.

• Asian Spine Journal
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• 제12권6호
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• pp.1043-1052
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• 2018

Study Design: Level III retrospective cross-sectional study. Purpose: To define and characterize the presentation, symptom duration, and patient/surgical risk factors associated with 'post-decompressive neuropathy (PDN).' Overview of Literature: PDN is characterized by lower extremity radicular pain that is 'different' from pre-surgical radiculopathy or claudication pain. Although it is a common constellation of postoperative symptoms, PDN is incompletely characterized and poorly understood. We hypothesize that PDN is caused by an intraoperative neuropraxic event and may develop early (within 30 days following the procedure) or late (after 30 days following the procedure) within the postoperative period. Methods: Patients who consented to undergo lumbar laminectomy with or without an instrumented fusion for degenerative lumbar spine disease were followed up prospectively from July 2013 to December 2014. Relevant data were extracted from the charts of the eligible patients. Patient demographics and surgical factors were identified. Patients completed postoperative questionnaires 3 weeks, 3 months, 6 months, and 1 year postoperatively. Questions were designed to characterize the postoperative pain that differed from preoperative pain. A diagnosis of PDN was established if the patient exhibited the following characteristics: pain different from preoperative pain, leg pain worse than back pain, a non-dermatomal pain pattern, and nocturnal pain that often disrupted sleep. A Visual Analog Scale was used to monitor the pain, and patients documented the effectiveness of the prescribed pain management modalities. Patients for whom more than one follow-up survey was missed were excluded from analysis. Results: Of the 164 eligible patients, 118 (72.0%) completed at least one follow-up survey at each time interval. Of these eligible patients, 91 (77.1%) described symptoms consistent with PDN. Additionally, 75 patients (82.4%) described early-onset symptoms, whereas 16 reported symptoms consistent with late-onset PDN. Significantly more female patients reported PDN symptoms (87% vs. 69%, p=0.03). Patients with both early and late development of PDN described their leg pain as an intermittent, constant, burning, sharp/stabbing, or dull ache. Early PDN was categorized more commonly as a dull ache than late-onset PDN (60% vs. 31%, p=0.052); however, the difference did not reach statistical significance. Opioids were significantly more effective for patients with early-onset PDN than for those with late-onset PDN (85% vs. 44%, p=0.001). Gabapentin was most commonly prescribed to patients who cited no resolution of symptoms (70% vs. 31%, p=0.003). Time to symptom resolution ranged from within 1 month to 1 year. Patients' symptoms were considered unresolved if symptoms persisted for more than 1 year postoperatively. In total, 81% of the patients with early-onset PDN reported complete symptom resolution 1 year postoperatively compared with 63% of patients with late-onset PDN (p=0.11). Conclusions: PDN is a discrete postoperative pain phenomenon that occurred in 77% of the patients who underwent lumbar laminectomy with or without instrumented fusion. Attention must be paid to the constellation and natural history of symptoms unique to PDN to effectively manage a self-limiting postoperative issue.