• 대한기계학회논문집B
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• 제35권1호
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• pp.23-31
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• 2011

원자로의 안전을 확보하고 운전성능을 정확히 예측하기 위해서는 핵연료에서 초임계압 냉각재로 전달되는 열전달량을 예측하는 것이 매우 중요하다. 초임계압 유체에서 열전달은 유사임계온도 부근에서 급격하게 변화하는 물성의 영향을 크게 받아 열전달량이 증가하기도 하고, 특정한 질량유속과 열유속 조건에서는 열전달량이 감소하는 현상을 보이기도 한다. 본 연구에서는 초임계압수냉각로(SCWR)의 핵연료집합체 부수로의 수력 직경과 유사한 내경 4.57 mm 원형관 안에서 상 하향 방향으로 흐르는 $CO_2$로 전달되는 열전달량(실제로는 원형관 외벽온도)을 다양한 조건에서 측정하고 분석하였다. 총 7,250개의 실험결과를 기존의 초임계압 강제대류 상관식들로 예측한 결과와 비교하여 그 상관식들의 정확성을 검토하였으며, 부력매개변수 $\overline{Gr}_b/(Re^{2.7}_b\overline{Pr}^{0.5}_b})$를 도입하여 혼합대류 영역에서도 적용할 수 있도록 기존의 상관식을 확장하였다. 그리고 기존의 열전달열화 발생 조건을 본 실험의 열전달열화 조건과 비교하여 적용성을 평가하였다.

• 정신신체의학
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• 제22권1호
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• pp.40-45
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• 2014

연구목적 경도인지장애와 치매는 인지기능의 퇴행과 우울 등과 같은 신경정신증상을 나타낸다. 이들의 진단에 도움을 줄 수 있는 다양한 진단 도구 중 혈중 호모시스테인 농도를 측정하는 방법이 있으며, 연구에 따르면 혈중 호모시스테인 농도의 증가는 알쯔하이머병, 우울증 그리고 다른 신경정신질환의 발생위험을 증가시킨다. 본 연구는 혈중 호모시스테인이 인지기능장애와 연관된다는 사실을 기초로 경도인지장애와 알쯔하이머형 치매에서 우울증상 유무에 따른 혈중 호모시스테인 농도를 분석해보았다. 방법 경도인지장애, 알쯔하이머형 치매로 진단된 환자 86명이 참여하였고 혈액검사를 통해 혈중 호모시스테인 농도를 측정하였다. 환자들의 전반적인 인지기능 및 심각도의 단계 평가는 한국판 간이정신상태검사(MMSE-KC)와 전반적 퇴화척도(Global Deterioration Scale, GDS), 치매임상평가척도(Clinical dementia rating, CDR)를 이용하여 측정하였고, 우울증상 유무에 대한 평가는 한국판 노인우울척도(Korean version of Geriatric Depression Scale, K-GDS)를 통해 측정하였다. 결과 혈중 호모시스테인 농도는 경도인지장애군 중 우울증상이 있는 군에서 우울증상이 없는 군보다 통계적으로 유의한 높은 수치를 보였다. 치매환자군에서는 우울증상이 있는 군과 우울증상이 없는 군사이에 통계적으로 유의한 차이는 없었다. 상관분석에서 혈중 호모시스테인 농도와 MMSE-KC는 유의한 음의 상관 관계를 보였고, CDR, GDS는 유의한 양의 상관 관계를 보였다. 결론 이러한 결과는 혈중 호모시스테인 농도의 증가가 인지기능저하와 우울증의 위험인자라는 사실을 나타낸다. 특히 본 연구에서는 경도인지장애 환자군에서 혈중 호모시스테인 농도와 우울증상 간의 의미있는 연관성을 제시하였다. 본 연구 중의 몇 가지 제한점을 보완한 좀 더 대규모의 연구가 필요하다.

• Journal of Veterinary Science
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• 제21권2호
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• pp.17.1-17.11
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• 2020

Dehydration, electrolyte disturbance, and acid-base imbalance are the most significant consequences of diarrhea in calves. We aimed to determine blood gas, hematological, electrolyte, and biochemical values and investigate the relationship between the physical status and blood parameters in Korean native calves (KNCs) with diarrhea. One hundred eighty KNCs with diarrhea (age < 75 days) were investigated. Blood samples were collected from the external jugular vein and analyzed using a portable clinical blood gas analyzer. The measured parameters were statistically compared according to the status of physical activity, dehydration, or prognosis. The mean values of parameters in the Calves with diarrhea showed metabolic acidosis, hyponatremia, and azotemia. The mean values of potassium, chloride, hematocrit, and hemoglobin were in the upper limit of their reference ranges. More than 75% of the calves had metabolic acidosis caused by bicarbonate loss, and 63.6% had high blood urea nitrogen (BUN) values. Moreover, BUN showed the highest correlation with the physical activity status and dehydration. pH, base excess of the extracellular fluid (BE), anion gap, potassium, hematocrit, bicarbonate, and hemoglobin were closely correlated with physical deterioration and dehydration (p < 0.001). BUN, pH, BE, and anion gap were closely correlated with physical deterioration and dehydration. These correlations between clinical symptoms and blood gas parameters can be clinically relevant in predicting the status of parameters according to clinical symptoms.

• 한국보건간호학회지
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• 제31권2호
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• pp.244-256
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• 2017

Purpose: This research was conducted to identify methods of inducing health promotion behavior, perceived health status, social participation and empowerment in the frail elderly receiving home visiting services. Methods: The subjects were 255 frail elders aged over 65 registered in the home visiting services of five public health centers in Daegu. Data were collected from June 9 to August 10, 2015. Data were analyzed by descriptive statistics, t-test, ANOVA, Scheffe's test and Pearson's correlation coefficient using SPSS Win 18.0. Results: The mean health promotion behavior, perceived health status, social participation and empowerment scores were 2.56 (${\pm}0.33$), 7.11 (${\pm}1.98$), 2.60 (${\pm}0.69$) and 2.90 (${\pm}0.29$), respectively. There was significant difference in health promotion behavior by client classification and life satisfaction. There were significant differences in perceived health status by life satisfaction, social participation by religion and client classification and empowerment by past jobs. Health promotion behavior, perceived health status, social participation and empowerment were positively correlated. Conclusion: An integrative health care program that includes these significant variables of subjects is essential to management and prevention of deterioration of frailty in elderly.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.704-707
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• 1999

Partial discharge(PD) in air insulated electric power systems is responsible for considerable power lossesfrom high voltage transmission lines. PD in air often leads to deterioration of insulation by the combined action of the discharge ions bombarding the surface and the action of chemical compounds that are formed by the discharge and may give rise to interference in ommunication systems. PD can indicate incipient failure. Thus understanding and classification of PD in air is very important to discern source of PD. In this paper, we investigated PD in air by using statical method. We classified air discharge with corona, surface discharge and cavity discharge by source of discharge. we used the mean pulse-height phase distribution $H_{qmean}(\psi)$, the max pulse-height phase distribution $H_{qmax}(\psi)$ , the pulse count phase distribution $H_n(\psi)$ and the max pulse height vs. repetition rate $H_{q}(n)$ for analysis PD pattern. We used statistical operators, such as skewness(S+. S-1, kurtosis(K+, K-), mean phase(AP+. AP-), cross-correlation factor(CC) and asymmetry from the distribution.

• 한국수자원학회논문집
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• 제49권2호
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• pp.155-164
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• 2016

남조류의 대번성은 특정 생물종의 감소와 물고기의 서식처를 감소하게 하는 결과를 가져와서 생태계에 상당한 교란을 가져오고 4대강의 수질을 위협하고 있다. 조류의 대번성에 영향을 미치는 인자를 해석하기 위해서 전통적으로 클로르필 a의 농도와 환경인자간의 교차상관함수를 계산하는 방식이 수행되어왔다. 교차상관함수에 사용되는 원 시계열 자료는 추계구조에 의해 영향을 받기 때문에 시계열 데이터의 추계학적인 구조를 파악하고 외부의 영향을 제거하는 선백색화 기법을 도입하였다. 이와 같은 모의과정은 모형구조의 파악, 매개변수추정, 선택된 모형의 자가진단수행등의 일련의 과정으로 진행된다. 선백색화 처리된 데이터를 이용하여 배타적 상관분석을 실시하였고 원데이터의 결과와 비교하였다. 이와 같은 과정은 조류농도 발생의 영향 인자를 구분하기 위해서도 유용한 과정이고 다른 환경인자들 사이에서의 인과성을 규명하는데도 유용하다.

• 한국치위생학회지
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• 제15권2호
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• pp.217-223
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• 2015

Objectives: The purpose of this study is to investigate cognitive function, performance of activities of daily living, and recognition on oral health with the cognitive function testto dementia or dementia-suspected patients in the outpatients. Methods: The subjects were 94 dementia or dementia-suspected patients visiting C University hospital for the dementia test. Study instruments included Korea Mini-Mental State Examination KMMS, The Bayer-Activities of Daily Living Scale; B-ADL, Seoul-Instrumental Activities of Daily Living; S-IADL, Global Deterioration Scale; GDS, Korean Dementia Screening Questionnaire; KDSQ, and underlying diseases. Results: Dementia or dementia-suspected patients were 42 by KMMSE test, 25 patients had impaired functioning of daily living by B-ADL test, 27 patients showed the presence of depression by GDS test, and 45 patients showed impaired functioning of daily living. There was a statistically significant difference in the subjective recognition on oral health conditions. There was a statistically significant difference in the subjective recognition on oral health conditions by ADL. There was a positive correlation between the cognitive function and ADL performance. Higher cognitive function is proportional to ADL performance. Conclusions: The cognitive function was closely associated with ADL and subjective oral health conditions.

• Journal of Computing Science and Engineering
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• 제6권1호
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• pp.1-11
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• 2012

Computed tomography (CT) images are widely used for the analysis of the temporal evaluation or monitoring of the progression of a disease. The follow-up examinations of CT scan images of the same patient require a 3D registration technique. In this paper, an automatic and robust registration is proposed for the rigid registration of 3D CT images. The proposed method involves two steps. Firstly, the two CT volumes are aligned based on their principal axes, and then, the alignment from the previous step is refined by the optimization of the similarity score of the image's voxel. Normalized cross correlation (NCC) is used as a similarity metric and a downhill simplex method is employed to find out the optimal score. The performance of the algorithm is evaluated on phantom images and knee synthetic CT images. By the extraction of the initial transformation parameters with principal axis of the binary volumes, the searching space to find out the parameters is reduced in the optimization step. Thus, the overall registration time is algorithmically decreased without the deterioration of the accuracy. The preliminary experimental results of the study demonstrate that the proposed method can be applied to rigid registration problems of real patient images.

• The Plant Pathology Journal
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• 제21권2호
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• pp.87-92
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• 2005

The structural differences between healthy and diseasedpanicle necks caused by Pyricularia oryzae were observed using electron-microscope. In the diseased panicle neck, the infection hyphae of the rice blast pathogen grew through the sclerenchymatous fiber tissue and reached to the central internal lacuna. Since the pathogen grew through the sclerenchymatous fiber tissues, the vascular bundle composed with xylem and phloem had been destroyed and finally the nutrients from the leaf and stem were not able to be transported into the grains. Infection of panicle base by the blast pathogen until 20 days after heading caused more than 50% of yield loss in both Jinmibyeo and Chucheongbyeo. There was a positive correlation between incidence of the panicle blast and rice yield losses. The regression equations between incidence of the panicle blast and yield losses were y= -3.61+496.7 ($R^2$=0.70) in Jinmibyeoand y=-3.93+520.2 ($R^2$=0.82) in Juanbyeo. The panicleblast caused deterioration of grain quality. Healthy grain rate was reduced by increase of panicle blast infection.

• 한국재료학회지
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• 제23권9호
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• pp.525-530
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• 2013

This study investigated the continuous cooling transformation, microstructure, and mechanical properties of highstrength low-alloy steels containing B and Cu. Continuous cooling transformation diagrams under non-deformed and deformed conditions were constructed by means of dilatometry, metallographic methods, and hardness data. Based on the continuous cooling transformation behaviors, six kinds of steel specimens with different B and Cu contents were fabricated by a thermomechanical control process comprising controlled rolling and accelerated cooling. Then, tensile and Charpy impact tests were conducted to examine the correlation of the microstructure with mechanical properties. Deformation in the austenite region promoted the formation of quasi-polygonal ferrite and granular bainite with a significant increase in transformation start temperatures. The mechanical test results indicate that the B-added steel specimens had higher strength and lower upper-shelf energy than the B-free steel specimens without deterioration in low-temperature toughness because their microstructures were mostly composed of lower bainite and lath martensite with a small amount of degenerate upper bainite. On the other hand, the increase of Cu content from 0.5 wt.% to 1.5 wt.% noticeably increased yield and tensile strengths by 100 MPa without loss of ductility, which may be attributed to the enhanced solid solution hardening and precipitation hardening resulting from veryfine Cu precipitates formed during accelerated cooling.