• 한국강구조학회 논문집
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• 제14권1호
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• pp.31-40
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• 2002

적층된 박벽 복합재료 보의 자유 진동에 관한 연구를 수행하였다. 박벽 C형강 복합재료의 동적 거동에 적용 가능한 일반적인 해석 모델을 개발하였다. 이 모델은 classical lamination theory를 기초로 두고 있으며, 임의의 적층 상태의 구성 즉, 대칭뿐만 아니라 비대칭의 적층 상태, 그리고 다양한 경계조건에 따른 휨과 비틀림 형상의 연계(coupling)을 설명하였다. 변위를 기반으로 한 일차원 유한 요소 모델은 박벽 복합재료 보의 고유 진동수와 그에 대응하는 진동 모드를 예측하기 위해 개발되었다. 운동방정식은 Hamiton의 원리로부터 유도되었으며, 수치적인 결과는 박벽 복합재 보에서 복합재료의 진동수와 모드 형상에 대해 적층각, 계수비, 그리고 경계조건의 영향을 얻을 수 있었다.

• BMB Reports
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• 제31권1호
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• pp.70-76
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• 1998

The final step in ethylene biosynthesis is catalyzed by the enzyme 1-aminocyclopropane-1-carboxylate (ACC) oxidase. ACC oxidase was extracted from mung bean hypocotyls and its biochemical characteristics were determined. In vitro ACC oxidase activity required ascorbate and $Fe^{2+}$, and was enhanced by sodium bicarbonate. Maximum specific activity (approximately 20 nl ethylene $h^{-1}$ mg $protein^{-1}$) was obtained in an assay medium containing 100 mM MOPS (pH 7.5), $25\;{\mu}M$ $FeSO_4$, 6 mM sodium ascorbate, 1 mM ACC, 5 mM sodium bicarbonate and 10% glycerol. The apparent $K_m$ for ACC was $80{\pm}3\;{\mu}M$. Pretreating mung bean hypocotyls with ethylene increased in vitro ACC oxidase activity twofold. ACC oxidase activity was strongly inhibited by metal ions such as $Co^{2+}$, $Cu^{2+}$, $Zn^{2+}$, and $Mn^{2+}$, and by salicylic acid. Inactivation of ACC oxidase by salicylic acid could be overcome by increasing the $Fe^{2+}$ concentration of the assay medium. The possible mode of inhibition of ACC oxidase activity by salicylic acid is discussed.

• 대한한의학회지
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• 제22권3호
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• pp.81-91
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• 2001

Objectives : This study was prepared for investigating the clinical features of stroke patients. Methods : We retrospectively reviewed the medical records of 177 patients who were admitted to the Dept. of Internal Medicine, College of Oriental Medicine, Kyungwon University with a diagnosis of stroke from Jan. I, 1999 to Dec. 31, 1999. Results : Ischemic stroke (74.0%) was more common than hemorrhagic stroke (19.8%). The proportion of males was 53.7%, of females was 46.3%, and the most prevalent age group is those in their sixties. Cerebral infarction was most frequently noticed in MCA territory, hemorrhage in putamen. Hypertension was the most common preceding disease, followed by diabetes mellitus. The rate of recurrence was high in cerebral infarction. The onset mode of cerebral infarction was sleeping and rising and of cerebral hemorrhage was acting. Most patients visited the hospital within 24 hours. The most common symptoms at admission were motor weakness and speech disorder. The most common complication was urinary tract infection. Admission period was 29.5 days. Physical treatment from onset in cerebral infarction and in cerebral hemorrhage was 17.4 and 22.0 days, respectively. Conclusions : Our study of CVA patients was similar to previous studies from 1994 to 1998. In most cases, western and oriental treatment and medicine were given synthetically. Prescription of sasang constitutional medicine had wide application.

• BMB Reports
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• 제50권1호
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• pp.31-36
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• 2017

High-dose caffeine uptake is a developmental stressor and causes food-avoidance behavior (aversion phenotype) in C. elegans, but its mode of action is largely unknown. In this study, we investigated the molecular basis of the caffeine-induced aversion behavior in C. elegans. We found that aversion phenotype induced by 30 mM caffeine was mediated by JNK/MAPK pathway, serotonergic and dopaminergic neuroendocrine signals. In this process, the dopaminergic signaling appears to be the major pathway because the reduced aversion behavior in cat-2 mutants and mutants of JNK/MAPK pathway genes was significantly recovered by pretreatment with dopamine. RNAi depletion of hsp-16.2, a cytosolic chaperone, and cyp-35A family reduced the aversion phenotype, which was further reduced in cat-2 mutants, suggesting that dopaminergic signal is indeed dominantly required for the caffeine-induced food aversion. Our findings suggest that aversion behavior is a defense mechanism for worms to survive under the high-dose caffeine conditions.

• 한국통신학회논문지
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• 제31권9A호
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• pp.884-891
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• 2006

무선 센서 네트워크에서의 센서 노드는 배터리로 동작하기 때문에 에너지에 대한 제약이 있다. 따라서 무선 센서 노드를 위한 효율적인 전력 관리 기법과 스케줄링 기법 설계가 중요한데, 본 논문에서는 운영체제 레벨의 소비 에너지를 줄이기 위한 알고리즘을 제안한다. 효율적인 배터리 사용을 위해 상황에 따라 필요한 컴포넌트에만 전원을 인가함으로써 센서노드의 에너지 소비를 줄일 수 있다. 본 논문에서는 제안한 알고리즘을 시뮬레이션 한 결과 기존의 duty 사이클과 비교하여 최대 56%의 에너지가 절약되었음을 알 수 있다.

• 한국표면공학회지
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• 제31권1호
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• pp.34-44
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• 1998

Stainless steel is being used widely lor various purposes due to its good corrosion resistance. There has becn much research to produce colored stainless sterl by several methods. In this experiment, we coated TixN film on the SUS304 substrate with thc DC magnetron sputtering system and studied the internal structurc and adhesive strength of the films as a function of the coating conditions. Before lhe specimen was coated, a sputter etching was very effective in removing the$\delta$ Fe(BCC) phase as well as the contaminant and oxide layer as well as increasing rotghness. Five-stage failure mode appeared with increased scratch load with the TIN films coated on the SUS304 in this manner ; tensile failure-,conformal failure-,buckling failure->chipping failurc and spalling Failure. When the failure was terminated at the initial stage, the film will have good adhesion. But, if syalling failure has occurred at the initial scratch, then the adhesion will be poor. The interlayer between thc coated film and thc substratc was homogeneously adhcsive when the $\gamma'-Fe_4N$ phase wasn't detected in the XRD analysis and the adhesive strength only was reduced by surPace defects. But, when the ,$\gamma'-Fe_4N$N phasc was detected in the XRD analysis, the adhesive strength was very poor.

• Current Research on Agriculture and Life Sciences
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• 제31권1호
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• pp.1-10
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• 2013

The exposure of food to ionizing radiation has been recognized as a safe and effective mode of food preservation in more than 55 countries. The benefits include eradication of insect pests, inactivation of food pathogens, extension of shelf-life, and improvement in food hygiene. Regulatory authorities around the world have emphasized the implementation of various national and international regulations to facilitate trade and development of consumers' confidence in purchasing irradiated foods. Therefore, the need for reliable irradiation detection methods has increased to enforce these regulations. At present, a number of promising analytical approaches have been developed and evaluated. Moreover, about 10 European Standards have been adopted as General CODEX Alimentarius methods for the detection of irradiated foodstuffs. However, most of these methods demand relatively expensive equipment and prolonged sample preparation. Therefore, simple and cost-effective approaches would be advantageous for rapid screening of foodstuffs. The suspected samples need to be analyzed further with more validated techniques to confirm the screening results. In this review, existing screening methods (i.e. physical, chemical, and biological) for the identification of irradiated foods have been outlined along with their principles, scopes and limitations.

• 한국통신학회논문지
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• 제31권10A호
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• pp.1020-1030
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• 2006

본격적인 지상파DMB 서비스가 시작되면서 사업자별로 다양한 데이터 서비스를 준비하는 등 비즈니스 모델 개발에 주력하고 있다. 이에 따라 DMB에 적합한 제한수신 시스템의 필요성이 이슈화되면서 국내에서는 현재 표준화 작업이 활활발히 진행되고 있다. 본 논문은 지상파DMB 방송환경에서의 적용을 목적으로 하는 지상파DMB 제한수신 서비스를 위한 앙상블 재다중화기와 수신 검증 플랫폼의 설계 및 구현 방법에 관해 제안한다. 또한 제안된 앙상블 재다중화기를 통하여 스크램블링된 앙상블 스트림을 송출하고, 수신검증 플랫폼을 통하여 적용된 스크램블 모드에 따라 디스크램블링 및 디코딩하여 이를 디스플레이 함으로써 그 성능을 검증하였다.

• 한국통신학회논문지
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• 제31권10A호
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• pp.968-975
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• 2006

고속 데이터 전송을 위하여, 송수신단에 다중 안테나를 사용함으로써 독립적인 페이딩 채널을 다수개 형성하여 다이버시티 이득과 코딩 이득을 동시에 얻는 MIMO(Multiple-Input Multiple-Output) 방식에 대한 연구가 활발히 진행되고 있다. 하지만 아직 UWB(Ultra Wide Band) 시스템과의 간섭에 대한 분석은 이루어지고 있지 않다. 이에 본 논문에서는 공간 다이버시티 특성을 가진 블록 코드를 OFDM 시스템에 적용하여, MIMO-OFDM 수신기에 인접한 UWB 기기로부터 SFBC(Space Frequency Block Code)-OFDM 시스템과 SFTC(Space Frequency Trellis Code)-OFDM 시스템에 .미치는 간섭 영향을 MIMO 채널 환경에서 성능을 분석하였다. 시뮬레이션 결과 SFTC-OFDM 시스템이 MB(Multi Band)-OFDM UWB 간섭에 대해 SFBC-OFDM 시스템보다 더 강인한 성능을 보여주었다.

• 한국압력기기공학회 논문집
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• 제7권4호
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• pp.31-37
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• 2011

Pressurized Water Reactor Owners Group(PWROG) proposed and applied a risk-informed inservice inspection(RI-ISI) program to alternate existing ASME Section XI periodic inspections. The RI-ISI programs enhance overall safety by focusing inspections of piping at high safety significant(HSS) and locations where failure mechanisms are likely to be present, and by improving the effectiveness on inspection of components because the examination methods are based on the postulated failure mode and the configuration of the piping structural element. The RI-ISI programs can reduce NDE, man-rem exposure, costs of engineering analysis, outage duration and chance of complicating plant operations etc. RI-ISI methods of piping inservice inspection were applied on 3 units(KSNP : Korea Standard Nuclear Power Plant) and are scheduled to apply on the other units. In this paper, we compared and showed the results of the 2 units and we concluded that the RI-ISI application could enhance and maintain plant safety and give unquantifiable benefits.