• Journal of Plant Biotechnology
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• 제31권3호
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• pp.225-230
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• 2004

방사선에 노출된 고추유묘의 잎으로부터 세포핵을 분리하여 단세포전기영동방법인 comet 분석을 통하여 핵 DNA의 손상정도를 조사하였다. Comet 분석에서 꼬리부분의 길이 (T)와 머리부분의 길이 (H)를 측정하여 T/H 비율을 조사하였다. 무처리세포는 T/H 비율이 1.28이었으나 50 및 100 Gy의 방사선을 처리한 세포는 각각 3.54 및 3.39로 방사선처리에 의해 상당량의 핵 DNA가 손상을 입은 것으로 나타났다. Comet의 head-DNA량은 무처리가 76.8%였으나 50 및 100 Gy를 처리한 세포는 각각 55.9% 및 59.5%를 보였다. 고선량의 방사선을 처리하기 전에 미리 20 Gy 이하의 저선량 방사선을 종자에 전처리하였을 경우 종자의 발아 및 생장에 대한 영향은 없었지만, 후속 고선량에 대한 핵 DNA의 손상은 경감되는 경향을 보였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.581-584
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• 2008

본 연구에서는 판상-링형 구속시험방법의 유효성 평가를 위하여 그 특성을 국내.외에서 제안된 콘크리트 구속수축시험방법과 비교하여 간편하고 정량적인 수축균열 평가방법의 개발을 위한 기초자료를 제시하고자 하였다. 판상-링형 구속시험방법의 적정 시험체 치수를 검토하기 위하여 시험체 내부링 직경 100, 150 및 200mm, 시험체 높이 30 및 50mm에 대하여 온도 20${\pm}$3$^{\circ}$C, 습도 60${\pm}$5%의 항온항습조건에서 양생 후 마이다스 프로그램을 이용한 3D Solid 요소의 수치 해석, 건조수축변형, 구속수축응력, 균열면적 및 균열 포인트 측정 등 콘크리트의 구속수축균열 특성을 평가하였으며, 그 결과 콘크리트 링 시험체 내부 링 직경 최소 150mm이상, 높이 50mm에서 변별력 있는 평가가 가능한 것으로나타났다. 본 연구를 바탕으로 향후, 판상-링형 구속시험방법에 있어서 온도, 풍속 등의 환경조건 및 배합조건에 따른 콘크리트의 구속수축균열특성에 관한 연구가 필요할 것으로 사료된다.

• 한국산업보건학회지
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• 제15권1호
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• pp.61-70
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• 2005

This study investigated the spinal loads(L5/S1 disc compression and shear forces) predicted from four biomechanical models: one EMG model and three optimization models. Three objective functions used in the optimization models were to miminize 1) the cubed muscle forces : MF3, 2) the cubed muscle stress : MS3, 3) maximum muscle intensity : MI. Twelve healthy male subjects participated in the isometric voluntary exertion tests to six directions : flexion/extension, left/right lateral bending, clockwise/ counterclockwise twist. EMG signals were measured from ten trunk muscles and spinal loads were assessed at 10, 20, 30, 40, 50, 60, 70, 80, 90%MVE(maximum voluntary exertion) in each direction. Three optimization models predicted lower L5/S1 disc compression forces than the EMG model, on average, by 31%(MF3), 27%(MS3), 8%(MI). Especially, in twist and extension, the differences were relatively large. Anterior-posterior shear forces predicted from optimization models were lower, on average, by 27%(MF3), 21%(MS3), 9%(MI) than by the EMG model, especially in flexion(MF3 : 45%, MS3 : 40%, MI : 35%). Lateral shear forces were predicted far less than anterior-posterior shear forces(total average = 124 N), and the optimization models predicted larger values than the EMG model on average. These results indicated that the optimization models could underestimate compression forces during twisting and extension, and anterior-posterior shear forces during flexion. Thus, future research should address the antagonistic coactivation, one major reason of the difference between optimization models and the EMG model, in the optimization models.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.455-465
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• 2006

In this study, the effect of scour was evaluated by regional and geotechnical characteristics and back data were accumulate for the design against scour through the local erosion characteristics evaluation of the Inchon coast. The erosion characteristics for the undisturbed soil samples collected near the main locations at the Incheon 2nd bridge, the Hwangyeong bridge, and a coast road in Songdo, are determined quantitatively through the scour rate tests. On the basic soil properties test, the bed around the Inchon coast chiefly consists of fined grained soils, and the soil samples were classified as silty clay(ML) or clay(CL) under the Unified Soil Classification System. On the scour rate test, the critical shear stress increases when the undrained shear strength increases as of the general trend of fine grained soils, and the average scour rate for the maximum velocity by 100 year flood is 173mm/hr at the Incheon 2nd bridge, 67mm/hr at the Hwangyeong bridge and 10mm/hr at a coast road in Songdo, respectively. Comparing to the scour rate of coarse grained soil, that of the bed around the Inchon coast is turned out to be very low. Therefore, the relative ability of the bed around the Inchon coast to resist erosion is assumed to be very high.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.154-161
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• 2004

The flat dilatometer test(DMT) is a geotechnical tool to estimate in-situ properties of various types of ground materials. The undrained shear strength is known to be the most reliable and useful parameter obtained by DMT. However, the existing relationships which were established for other local deposits depend on the regional geotechnical characteristics. In addition, the flat dilatometer test results have been interpreted using three intermediate indicesmaterial index($I_p$), horizontal stres index($K_p$), and dilatometer modulus($E_p$) and the undrained shear strength is estimated only by using the horizontal stress index($K_D$). In this paper, an artificial neural network was developed to evaluate the undrained shear strength by DMT and the ANN, based on the $p_0,\;p_1,\;p_2,\;{\sigma}'_v_0$, and porewater pressure. The ANN which adopts the back-propagation algorithm was trained based on the DMT data obtained from Korean soft clay. To investigate the feasibility of ANN model, the prediction results obtained from data which were not used to train the ANN and those obtained from existing relationships were compared.

• 중환자간호학회지
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• 제11권2호
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• pp.75-85
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• 2018

Purpose : The purpose of this study was to examine the possible direction of critical care nursing research in the future by analyzing the trends of recent Korean studies. Method : Using a database search, we selected 263 articles on critical care nursing that were published in Korean journals between 2008 and 2017. Then, we conducted an integrative review of the contents of the selected articles and analyzed the English abstracts using the relevant packages and functions of the R program. Results : The number of studies concerning critical care nursing has increased over the 10-year period, and the specific topic of each study has diversified according to the time at which it was conducted. In terms of quality, the majority of the research was published in high-level academic journals. The key words regularly studied over the past decade were: knowledge, delirium, education, restraint, stress, and infection. Studies related to vancomycin-resistant enterococci infection, compliance, and standards have decreased, while studies related to death, communication, and safety have increased. Conclusion : Randomized controlled trials and protocol research for evidence-based critical care need to be conducted, as does research on family involvement. The key word analysis of unstructured text used in this study is a relatively new method; it is suggested that this method be applied to various critical care nursing research and develop it methodologically.

• 한국지역사회생활과학회지
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• 제27권3호
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• pp.419-435
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• 2016

The purpose of the present study was to suggest the design requirements for Korean naval duty uniforms by evaluating the physiological and psychological comfort while wearing the uniforms. Two sets of wear trials were conducted with summer uniforms(eight young males) and winter uniforms(seven other young males). The summer wear trial consisted of 10-min rest, 60-min exercise, and 10-min recovery at an air temperature($T_{air} $) of $33^{\circ}C$ and 62%RH, followed by 10-min recovery at a $T_{air} $ of $23^{\circ}C$ and 64%RH(total 90 min). The winter wear trial consisted of 20-min rest at $T_{air} $ $20^{\circ}C$ and 55%RH, 25-min rest, 30-min exercise, and 35-min recovery at a $T_{air} $ of 0oC and 43%RH(total 110 min). Rectal and seven skin temperatures, clothing microclimate, heart rate, oxygen consumption, total sweat rate, and subjective perceptions were measured during the wear trials. By evaluating the experimental results from the wear trials, we extracted the following psycho-physiological design requirements to improve the current Korean naval uniforms: (1) It is important to maintain the skin temperatures within their comfort range, which depends on the body region (higher than $30^{\circ}C$ in winter, but less than $35^{\circ}C$ in summer). (2) In summer, the feet should be protected from the high heat of the ship floor surface. (3) In summer, sweat from the back should be sufficiently absorbed and allowed to dry quickly.

• Journal of Advanced Marine Engineering and Technology
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• 제36권6호
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• pp.802-807
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• 2012

SPR(Self-piercing rivet)은 판재 접합법으로서 스틸과 알루미늄 합금 등의 이종재료 접합에 사용되고 있다. 접합 공정은 피어싱을 포함한 소성변형이 함께 이루어진다. 프레스에서 펀치의 아래에 있는 리벳은 상부판재를 피어싱하고 하부 판재와 기계적으로 맞물리며 소성변형되어 결합된다. 본 논문에서는 SPR을 제작하기 위한 단조공정을 설계하였고, 이를 위하여 상용 유한요소해석 코드인 DEFORM-2D를 이용하여 해석하였다. 리벳 제작을 위한 단조공정의 설계에서 공정 순서, 성형성, 단조하중, 응력과 변형률 분포 등을 조사하였다. 또한 시뮬레이션 결과를 통하여 적합한 단조공정을 설계하였다. 설계된 공정은 업세팅, 헤드부 성형, 후방압출, 두 번째 챔퍼링의 네 단계로 구성된다. 그리고 단조공정에 대한 시뮬레이션 결과는 같은 조건을 적용한 실험 결과를 통하여 검증하였다.

• Journal of Preventive Medicine and Public Health
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• 제24권3호
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• pp.305-313
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• 1991

In order to investigate industrial fatigue due to visual display terminal (VDT) work of banking operations the questionnaire survey for subjective symptoms of fatigue was carried out on 470 bank clerks who had been engaged in VDT work for various length of work hours. The questionnaires comprised three groups of 10 items each, representing dullness and sleepiness (level of cerebral activation), difficulty in concentration (level of motivation) and bodily projection of fatigue. The results were as follows : 1. Of the 30 items of questionnaires, the highest percentage was accounted for by 'eye strain' (51.5% ), followed by 'feel stiffness in the neck or the shoulders'(33.4%), 'feel a pain in the low back'(26.8%), 'whole body feels tired'(19.6%) and 'feel headache'(17.9%) in the order of sequence. 2. The average weighted score for the first group of questionnaire items (dullness and sleepiness) was the largest among three groups and was followed by 'the third cup (bodily projection of fatigue) and the second item group (difficulty in concentration) in the order of sequence, suggesting the heavier mental stress of VDT work in banking operations rather than physical burden. 3. In terms of the age and sex of workers, work duration and VDT work percentage, the difference in average weighted score was noted only between sex, the score of female being larger than that of male. 4. The complaint rates of subjective symptoms showed close associations with the subjective optimums of room temperature, ventilation, illumination and noise level. 5. The significant correlation was showed between age, work duration and item of 'whole body feels tired', between VDT work percentage and items of 'eye strain' and 'feel stiffness in the neck or shoulders' and between all items of subjective symptoms.

• 농업과학연구
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• 제44권2호
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• pp.228-234
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• 2017

Feed intake (FI) of sows during lactation is a serious problem because sows require a large amount of energy for high milk production during lactation. Providing a palatable diet is important for lactating sows to cope with the stress of breast-feeding. Palatability can be increased by adding sweeteners to diets. This study was conducted to evaluate the effects of saccharin (sweetener) on growth performance, fecal moisture, and litter performance of lactating sows. Sixteen sows were randomly allotted to one of two dietary treatments in a 27-day trial starting from lactation. The two dietary treatments were supplemented with 0 and 0.2% saccharin (sweetener), respectively. Average daily feed intake (ADFI) was increased (p < 0.05) and back fat loss (BFL) was decreased (p < 0.05) in sows fed saccharin supplementation diets compared with sows fed control diet during lactation. However, sows' body weight loss, body condition score (BCS), fecal score, and the number of piglet survival were not different (p > 0.05) among dietary treatments. The two dietary treatments also had no significantly different effect (p > 0.05) on litter weight and average daily gain (ADG) of piglets. Taken together, saccharin has no significant effect on growth performance of piglets but it can increase FI and reduce BFL of lactating sows.