• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.2
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• pp.99-106
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• 1987

Annealing were performed to investigate the behaviors of the residual stress remaining on the member of a steel structure. According to the fatigue test, the welding part has higher fatigue crack growth rate than the base metal part because the hardening of welding part reduce fracture toughness. However, the heat treatment decrease the hardness and increase the resistance to failure. Thus, the fatigue crack growth rate is improved and it reaches the minimum at $650^{\circ}C$. Elber' s equation includes the effect of the crack-close so that this equation provides a lower the fatigue crack growth rate than Paris-Erdogan' s equation, the Elber's curves show no significant difference to indentify the effect of the residual stress. The Pop loading along the crack length increases as the hardness goes higher. The heat treatment not only decrease the hardness, and the fatigue crack growth rate, but increase the absorption energy and fracture toughness on the member of a steel structure. As the result, the heat treatment produces the resistant ability to cracking which can reduce the degree of danger to failure.

• Journal of Navigation and Port Research
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• v.40 no.3
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• pp.159-164
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• 2016

The goal of this study is to implement a communication system that can monitor the status of the nacelle using the power cable itself, without the dedicated communication lines such as an UTP cable and optical fiber for the offshore wind turbine. An inductive coupling powerline communication system for a MW class offshore wind turbine was proposed and its communication performance was demonstrated. The inductive couplers was designed for operation at up to 500 A using a ferrite composite materials. Field test was carried out on the wind farms of Jeju island. Using the iperf communication test program, we have obtained more than 15 Mbps data transmission rate through the 100 m power cable that was installed between the nacelle and the bottom of the power converter. In the data transmission stability test for a week, there was no failure ever. The minimum transmission rate was 15 Mbps and the average data rate was about 20 Mbps. Next, we have installed an infrared camera inside the nacelle in order to measure the temperature distribution and variation of the nacelle. The real-time thermal image taken by the camera was successfully sent to the monitoring system without error.

• Korean Security Journal
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• no.29
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• pp.115-137
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• 2011

The purpose of this study was to look into impacts of career barriers and college major satisfactions on career preparation behaviors of Security major college students. The subjects of this study were collected among 200 security major students attending universities in Choungnam and Junnam Provinces, and 170 out of 200 were analyzed. Based on collected data, exploratory factor analysis, correlation analysis, multiple regression analysis, and one-way ANOVA were conducted using SPSS 18.0. According to the result, career barriers showed negative correlations on career preparation behaviors, and self-concept clarity deficiency showed significant impact on it. College major satisfactions showed positive correlations, and major satisfaction showed significant impact on it. Also result shows college junior and senior students experience less career barriers compare to freshman and sophomore students, and college junior and senior students were more satisfied on the college major satisfactions as well. The study has found important implications of impacts of career barriers and college major satisfaction on career preparation behaviors. In long term, the finding of the study seem to provide useful insights for security major students and Human Resource Personnel to execute the process of career preparations and related counseling effectively.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.13-13
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• 2009

현재 열간단조 금형을 제작함에 있어 육성용접을 실시하는 방법이 금형강 STD61, STD11 등으로 제작하는 방법에 비해 보수나 비용적인 측면에서 이점을 가지고 있기 때문에 점차적으로 증가하고 있는 추세이다. 열간단조 공정에서 금형은 $1000^{\circ}C$이상의 고온재료와 반복접촉하게 된다. 이때 이형제의 사용은 급속냉각 및 급속가열의 열피로를 가속시킨다. 또한, 금형은 반복충격에 의한 기계적 피로를 받게 된다. 이러한 금형의 사용환경을 고려한 FCW는 종래 고가의 $2.8{\sim}3.2{\Phi}$인 외국산 FCW를 사용하였으나 이를 대체한 $3.2{\Phi}$ 태경 FCW가 국내에서 개발되었다. 하지만 개발된 FCW를 사용하여 제작된 금형의 수명이 부족한 현상이 발생하였다. 이에 금형의 수명을 연장시킬 수 있는 내균열성 및 내열충격성을 확보한 태경 FCW의 개발과 개발된 FCW의 성능평가가 요구되었다. 특히 열간단조 금형에 있어서 중요한 내열충격성의 경우 가열과 냉각의 반복 Cycle에 의한 Thermal shock의 평가가 대부분이며 높은 Cycle로 인해 많은 시간이 걸리며, 또한 가열과 냉각을 오갈 수 있는 고가의 시험장치가 요구된다. 그러므로 개발된 FCW 육성용접부의 내균열성 및 내열충격성을 평가할 수 있는 방법에 대한 연구와 특히 내열충격성을 시간이 적게 걸리면서도 경제적으로 평가할 수 있는 방법에 대한 연구가 필요하다. 본 연구의 목적은 열간단조 금형 육성용접부의 내균열성 및 열충격특성을 평가할 수 있는 방법에 대한 검토와 특히 내열충격성에 대해 J.W.Kim등의 시험방법을 참고하여 시간이 적게 걸리면서 저 비용으로 열 충격특성을 평가할 수 있는 시험법을 고안하는 것이다. 이를 위한 방법으로 육성용접부의 내균열성을 평가하기 위한 상온 Bending을 실시하였고, 내열충격성을 평가하기 위한 염욕로를 이용하는 고온 Bending을 고안하여 실시하였다. 상온 Bending, 고온 Bending 모두 3점 굽힘시험을 적용하였다. 고온 Bending의 가열방법으로는 염욕로를 사용하여 시편이 대기중에서 약 $850^{\circ}C$의 온도가 될 수 있도록 하였다. 시편은 각각 열처리를 하여 요구 경도를 확보하였고, 이를 염욕로에서 5분간 가열 및 유지하여 취출 후 굽힘하중을 가하여 변위의 정도로 열충격을 평가하는 방법을 사용하였다. 상온 Bending은 극한변형량과 파단부 극한응력으로, 고온 Bending은 고온 극한변형량으로 평가를 하였고, 외국산 FCW를 사용한 육성용접부를 비교대상으로 하였다. 평가 결과 개발된 국산 $3.2{\Phi}$ 태경 FCW의 성능은 외국산 FCW와 유사하거나 우수한 것으로 평가되었고, 실제 금형을 제작하여 현장에 적용한 결과 금형의 수명이 연장된 것이 나타났다.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.387-394
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• 2019

In this study, in order to evaluate the damage and deterioration of the track components of sleeper floating track (STEDEF), the field samples(specimens) were taken from the serviced line over 20 years old, and the track components were visually inspected, and investigated by laboratory tests and finite element analysis. As a result of visual inspection, the damage of the rail pad and fastener was slight, but the rubber boot was worn and torn at the edges of bottom. The resilience pads were clearly examined for thickness reduction and fatigue hardening layer. As a result of spring stiffness test of rail pad and resilience pad, the deterioration of rail pad was insignificant, but the deterioration of resilience pad exceeded design standard value. Therefore resilience pad was directly affected by train passing tonnage. As a result of comparing the deterioration state of the field sample and the numerical analysis result, the stress and displacement concentration position of the finite element model and the damage position of the field sample were coincident.

• Journal of Life Science
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• v.33 no.3
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• pp.295-303
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• 2023

Immune and metabolic systems are important factors in maintaining homeostasis. Immune response and metabolic regulation are highly associated, so, when the normal metabolism is disturbed, the immune response changed followed the metabolic diseases occur. Likewise, obesity is highly related to immune response. Obesity, which is caused by an imbalance in energy metabolism, is associated with metabolic diseases, such as insulin resistance, type 2 diabetes, fatty liver diseases, atherosclerosis and hypertension. As known, obesity is characterized in chronic low-grade inflammation. In obesity, the microenvironment of immune cells became inflammatory by the unique activation phenotypes of immune cells such as macrophage, natural killer cell, T cell. Also, the immune cells interact each other in cellular or cytokine mechanisms, which intensify the obesity-induced inflammatory response. This phenomenon suggests the possibility of regulating the activation of immune cells as a pharmacological therapeutic strategy for obesity in addition to the common pharmacological treatment of obesity which is aimed at inhibiting enzymes such as pancreatic lipase and α-amylase or inhibiting differentiation of preadipocytes. In this review, we summarize the activation phenotypes of macrophage, natural killer cell and T cell, and their aspects in obesity. We also summarize the pharmacological substances that alleviates obesity by regulating the activation of immune cells.

• Journal of Practical Agriculture & Fisheries Research
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• v.13 no.1
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• pp.19-26
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• 2011

The machine transplanted rice has highly extended in the Republic of Korea due to a wage rise since 1976 and thus rice seedling raising nursery method has shifted from field into polyethylene film house. The rice seedling grown under a polyethylene film house was weak and tall because of limited sunlight and wind and so there was so complained among rice growing farmers in terms of missing hill and broken seedling after machine transplanting. In recent iron-coated seedling has reported on healthier and stronger than that of polyethylene film house. These seedlings were more stiff and thus more easy to handle during transplanting and less missing hills. The Iron-coated seed was proven to more stiff like seedling height, root growth and weight of shoot and root growth. This was more convenient during transfer of seedling raising box im machine transplanting. Thus, this study was carried out to grow a stiff and healthy seedling growth and development for machine transplanting. There were a normal seed germination and sprouting after iron-coated seeds treatment and this seedling was smaller and stiffer than that of untreated control. The leaf number and root growth of seedling which was iron-coated seeds would be better and total seedling fresh weight was greater than that of untreated control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.59-68
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• 1995

Investigated were the relationships between plumule elongation characteristics and seedling emergence of 46 varieties including native, improved and red rice varieties of Korea, and varieties from U.S.A., Italy, India, Japan under 1, 3, and 5cm deep sowing with irrigated and non-irrigated condition. Experiments were carried out in paddy field of sandy loam. There was heavy shower of 19.2mm on the next day of seeding and thereafter, clear and dry weather continued during the experiment period. Soil temperature averaged over 30 days after seeding was $16.4^{\circ}C$ at 3cm depth. Soil hardness increased linearly up to 2.5kg /$cm^2$ on the 14th day after seeding, on which date irrigated plot was irrigated through furrow, and up to 4kg / $cm^2$ on the 28th day in non-irrigated plot. Soil hardness dropped near to 0kg /$cm^2$ after irrigation and developed up to 2.5kg /$cm^2$ again by 28 days after seeding. Seedling emergence was higher in irrigated plots than non-irrigated plots at all seeding depths. Korean improved varieties were substantially lower in seedling emergence under non-irrigated condition of 1 cm deep sowing than those under irrigated condition. This poor seedling emergence resulted mainly from delayed emergence by exposing them to greater soil strength. Percent seedling emergence under irrigated and non-irrigated condition showed signifi-cant correlations at 3 and 5 cm deep sowing. Korean improved varieties belonged to the group of poor seedling emergence, and I taliconaverneco, Chinsura Boro and Weld Pally to best group under both irrigation conditions at 3 and 5cm deep sowing. Seedling emergence showed highly signifi-cant positive correlation with the plumule length of mesocotyl ＋ 1st internode ＋ incomplete leaf and of mesocotyl＋coleoptile. Among the characters constituting plumule length, incomplete leaf length showed greatest positive correlation followed by coleoptile and mesocotyl under irrigated condition at 3 and 5 cm deep sowing, and highest correlation with mesocotyllength followed by first internode and incomplete leaf under non-irrigated condition. Days to 50% seedling emergence at 1 cm deep sowing with irrigation showed great varietal variation of 10 to 30 days, and showed high significant negative correlations with percent seedling emergence under both irrigation conditions except for 1 cm deep sowing with irrigation, Days to seedling emergence revealed sig-nificant negative correlations with plumule characters except 2nd internode, showing highest cor-relation with incomplete leaf length.

• Journal of radiological science and technology
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• v.32 no.1
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• pp.87-93
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• 2009

Background/aim : Atherosclerotic disease at the origin of the vertebral arteries is one of the risk factors for vertebrobasilar ischemic disease. Assessment and visualization of the origin of the vertebral arteries with color doppler sonography is a non-trivial task. The aim of this study is to increase the visualization rate of the origin of the vertebral arteries with color doppler sonography. Materials and Methods : Color doppler sonography for the vertebral arteries included carotid arteries was performed to 198 patients. We first examined the vertebral artery in the upper neck in the direction of the subclavian artery to distinguish its origin more easily. If the vertebral artery origin was not visualized in natural position, the examiner pushed the transducer toward a clavicle or pushed the shoulder of patient by the other hand. The technical methods for visualization of the vertebral artery origin were classified into three grades: natural position, pushing the transducer, and pushing the shoulder of patient according to the depth (3.0 cm and shallower, deeper than 3.0 cm) of the origin. Results : The origin of the vertebral arteries could be visualized in 97% on the right and in 92% on the left. The origin of the vertebral arteries could be visualized in 98.6%, 1.4%, and 0.0% in natural position, pushing the transducer, and pushing the shoulder of patient, respectively, at shallower than 3.0 cm on the right side. The origin of the vertebral arteries could be visualized in 81.2%, 14.6%, and 4.2% in natural position, pushing the transducer, and pushing the shoulder of patient, respectively, at deeper than 3.0 cm on the right side. The origin of the vertebral arteries could be visualized in 85.4%, 10.7%, and 3.9% in natural position, pushing the transducer, and pushing the shoulder of patient, respectively, at shallower than 3.0 cm on the left side. The origin of the vertebral arteries could be visualized in 55.7%, 30.4%, and 13.9% in natural position, pushing the transducer, and pushing the shoulder of patient, respectively, at deeper than 3.0 cm on the left side. Conclusion : If the examiner pushes the transducer toward a clavicle or pushes the shoulder of patient by the other hand, when the vertebral artery origin during the color doppler sonography is not visualized in natural position, visualization rate of the origin of the both vertebral arteries is increased.

• Journal of Mushroom
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• v.19 no.1
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• pp.23-32
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• 2021

This study investigated the anti-hyperlipidemic and anti-obesity effects of Sparassis latifolia (S. latifolia) fruiting body powder in rats fed with a high fat and cholesterol diet (HFD). Rats were fed a normal control diet (ND), an HFD, an HFD supplemented with 5% fruiting body powder of S. latifolia (HFD+SL), or an HFD supplemented with 0.03% simvastatin (HFD+SS), for 6 weeks. The HFD group demonstrated considerable increase in body weight gain, the food efficiency ratio (FER), and plasma cholesterol and triglyceride levels, compared to the ND group. In contrast, the HFD+SL and HFD+SS groups showed significantly reduced body weight gain, food intake, and plasma cholesterol and triglyceride levels compared to the HFD group. In particular, the HFD+SL and HFD+SS diets significantly suppressed the occurrence of non-alcoholic fat deposits in the liver. Taken together, these results suggest that dietary supplementation of the fruiting body powder of S. latifolia in an HFD could lower the risks of hyperlipidemia, atherogenesis, and obesity and may be used as a functional food to manage cardiovascular disease and fecal lipid and cholesterol levels.