• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.430-433
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• 2003

Air-operated valve is one of principal valves that are using to control fluid flow. A period diagnosis for safety of power plants is necessary. But there are many difficulties such as economic loss caused by intone of high cost devices and a matter hard to deal with users. In this study we developed the diagnosis system that usersofpower plants are easy to handle. The diagnosis system is composed of database module, reliability analysis module, design safety nodule and diagnosis test and evaluation module.

• 신재생에너지
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• 제4권4호
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• pp.3-9
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• 2008

In design PV (photovoltaic) system, there are many important factors to consider for best site selection. It is essential to understand to know the amount of sunlight available and how to minimize the shadings. This study presents basic concepts for understanding sun's position and insolation. also it gives easy tools for topography analysis. Finally, this study shows some theoretical calculations of power generation losses by topographic obstacle's elevations and disadvantages in economic feasibility, that is about 7million won loss per year for case of 10 degree topography elevation with assuming average Korea's topography elevation as 5 degree.

• 산업기술연구
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• 제16권
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• pp.45-50
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• 1996

An experimental study os performed to examine the feasibility of using wastes steel furnace slag construction materials and its utility as a replacement for the natural resources to prevent the economic loss was investigated. A half factorial exprements was performed with the variables of W/C ratio, S/A, Coarse aggrigate/Slag ratio and slump as a preliminary study for optimum mix design of concrete. The results show that the W/C ratio and Slump ratio are the most important factor to the concrete strength. The substitute of waste Slag up to 100% has little influence, saying that it can substitute the coarse aggregate without damaging the concrete properties.

• 대한인간공학회지
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• 제29권4호
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• pp.455-463
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• 2010

Work-related musculoskeletal disorders (WMSDs) are recognized as leading causes of significant human suffering, loss of productivity, and economic burdens on our society. WMSDs are associated with work patterns that include fixed or constrained body positions, continual repetition of movements, force concentrated on small parts of the body, cold environment and vibration. Main effort to protect workers from WMSDs should focus on avoiding repetitive patterns of work through engineering controls which may include mechanization, ergonomic design of tools and equipment, and workplace layout. Where elimination of the risk factors is not practical, administrative controls involving job rotation, job enlargement and enrichment, teamwork should be considered.

• Journal of Ginseng Research
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• 제32권4호
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• pp.337-340
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• 2008

Seedlings of North American ginseng (Panax quinquefolius L.) were grown to full canopy establishment and then leaflet or leaf removal at different times applied to determine the effects on plant growth and performance. Leaf removal at 47, 57, 69 and 78 days after seeding resulted in 82.1, 59.8, 41.3 and 29.8% reduction, respectively, in root dry matter (economic yield) ; this indicates that leaf removal during the early root growth period causes greatest reduction in root yield. Removal of 1, 2, and 3 leaflets at 42, 52, 62 and 70 days from seeding reduced root weight at harvest (80 days from seeding) linearly, particularly at earlier removal dates. The perennating bud formed on all roots and was not influenced by treatment. This would suggest that if leaf loss occurs after canopy establishment the plant will re-grow the next year after the obligatory dormancy period.

• Journal of Preventive Medicine and Public Health
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• 제10권1호
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• pp.118-124
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• 1977

The features of crimes, their causes and backgrounds of 70 army delinquents, comparing with the controls, were studied from Nov. 1st, 1976 to Nov. 20, 1976 The results were as follows: 1. Most of the delinquents were from the adverse circumstances i. e. low education level, poor economic status, farmers and had got married. 2. The majority of the delinquents occurred within the first 2 years of the enlistment. 3. The rate of the parent-loss of the criminals was definitely higher than that of the controls. (48.6%) 4. Escapers from military service were over the half of them, and violence, steal and embezzlement were followed. The motivations of the escape from the military service was mostly domestic problem and illness; but a lot of the criminals also escaped for amusement and pleasure. 5. The prognosis of them was relatively favorable and constructive.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1993년도 제18회 학술대회 초록집
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• pp.77-84
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• 1993

Systems with journal bearings generally operate in large scale and under severe loading conditions such as steam generator turbines and internal combustion engines, in contrast to the machineries using rolling element bearings. Failure of the bearings in these machineries can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings.

• 대한수의학회지
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• 제48권2호
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• pp.219-221
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• 2008

We report the electrocution of Korean native cattle by a fallen electric wire, which caused the death of thirteen animals. The owner of the cattle felt an electric shock on touching the steel pen and found a fallen 220-V wire on the roof of the barn; additionally, the roof was singed. Clinically, the animals developed spasm, difficulty breathing, and excessive salivation. Histopathologically, many visceral organs revealed severe congestion or hemorrhage, which is consistent with previous reports. This study revealed that the proper installation of electric wires on farms is essential to prevent economic loss by electrocution.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.192-197
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• 1996

An experimental study was performed to examine the feasibility of using silicic wastes as construction materials for civil structures, and investigate its utility as a replacement for the favored nature resource to prevent the economic loss. In order to achieve this objective, mechnical properties of concrete containing silicic wastes is tested by investigating the strength development through parameters of water-binder ratios replacement 10 percent ratio with respect to curting conditions. The effect of stringth development is investigated for curing conditions when silicic wastes of 10 percent of cement-binder ratios is containde. Comparision on compressive strength of normal concrete and concrete containing silicic wastes at 28 day is conducted. The concrete with silicic wastes have larger compressive strength than of normal concrete by about 20 percent, when cured at 80 degree. The wastes concrete using silica sand shows increased strength, fracture toughness, elastic modulus and strain than the normal concrete, although the silicic wastes concrete could be able to satisfy the generally required strength for conventional concrete structures.

• 아동학회지
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• 제28권2호
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• pp.175-192
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• 2007

Qualitative research was used to discover factors, relationships, and practices affecting rearing of a grandchild by grandparents. Results showed that the grandparents' motives for rearing a grandchild were parental obligation and responsibility, the fate of unavoidable situations, feelings of worth and affection, helping household economy, and absence of another reliable place for child-rearing. Grandchild-rearing roles included substitute mother, disciplinarian, and playmate. Grandchild-rearing difficulties included such psychological problems as insufficient time for their own selves, concern that they might also raise another grandchild, conflicts with family members, economic problems, and physical problems such as grandparents' worsening health conditions, double pressures of housework and childcare, and stress from loss of memory and fatigue.