• Proceedings of the Korea Crystallographic Association Conference
• /
• 2002.11a
• /
• pp.20-20
• /
• 2002

Based on experimental and theoretical analyses, we suggested a new possibility that the CVD diamond films grow not by the atomic unit but by the charged clusters containing a few hundreds of carbon atoms, which form spontaneously in the gas phase [J. Crysta] Growth 62 (1996) 55]. These hypothetical negatively-charged clusters were experimentally confirmed under a typical hot-filament diamond CVD process. Thin film growth by charged clusters or gas phase colloids of a few nanometers was also confirmed in Si and ZrO₂ CVD and appears to be general in many other CVD processes. Many puzzling phenomena in the CVD process such as selective deposition and nanowire growth could be explained by the deposition behavior of charged clusters. Charged clusters were shown to generate and contribute at least partially to the film deposition by thermal evaporation. Origin of charging at the relatively low temperature was explained by the surface ionization described by Saha-Langmuir equation. The hot surface with a high work function favors positive charging of clusters while that of a low work function favors negative charging.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.69-72
• /
• 2005

The crystal structure of magnesium is hexagonal close-packed (HCP), so its formability is poor at room temperature. But formability is improved in high temperature with increasing of the slip planes. Purpose of this paper is to know about the mechanical properties of magnesium alloy (AZ31B), before warm and hot forming process. The mechanical properties were defined by the tension and compression tests in various temperature and strain-rate. As the temperature is increased, yield${\cdot}$ultimate strength, K-value, work hardening exponent (n) and anisotropy factor (R) are decreased. But strain rate sensitivity (m) is increased. As strain-rate increased, yield${\cdot}$ultimate strength, K-value, and work hardening exponent (n) are increased. Also, microstructures of grains fine away at high strain-rate. These results will be used in simulations and manufacturing factor for warm and hot forming process.

• Bulletin of the Korean Chemical Society
• /
• v.21 no.5
• /
• pp.493-496
• /
• 2000

By use of the rotational distribution expression previously derived based on the collisional time correlation function formalism, the rotational distributions of $CO_2$ vibrational ground state (00°0) after collisions with hot H, D, or Cl atom have been constructed. Energy and rotational quantum number parameters which can characterize the rotational distributions are also calculated and compared with those deduced from the experimental distribution. The results from this work would be very useful in predicting the rotational distributions in the lower J region for which experimental data are not available due to the interference from the ambient $CO_2$.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.331-336
• /
• 2003

The advanced spent fuel conditioning process(ACP) was proposed to reduce considerably the overall volume and radioactivity for effective management of the PWR spent fuel in respects on safety and economy. The ACP is under research and development, and have scheduled to perform hot test for demonstration of the ACP after several years. For hot test, hot cell facility of ${\alpha}{\gamma}$ type possess conservative safety is required essentially. A existing hot cell of ${\beta}{\gamma}$ type will be refurbished to minimize construction expenditures of hot cell facility. In this study, the design requirements are established, and the process detail work flow was analysed for the optimum arrangement to ensure effective process operation in hot cell. And also, the basic and detail design of hot cell facility and process and safety analysis was peformed to secure conservative safety of hot cell facility and process.

• Journal of the Korean Society for Heat Treatment
• /
• v.2 no.3
• /
• pp.61-73
• /
• 1989

• 월간산업보건
• /
• s.269
• /
• pp.37-39
• /
• 2010

• Journal of the Ergonomics Society of Korea
• /
• v.24 no.1
• /
• pp.37-41
• /
• 2005

Work related musculoskeletal disorders became a hot issue in Korea since many workers reported musculoskeletal disorder problems. Korean government enacted a law to require companies to take measures to prevent musculoskeletal disorders at work. This study found workers' WMSDs symptoms in squatting work posture which the rate of the occurrence was relatively high among work types to bring about WMSDs in railroad cars maintenance works and analyzed to compare the hazardous jobs in the industrial safety health law in South Korea with the caution jobs in Washington State in U.S. The hazardous jobs in South Korea were more effective in squatting work posture from this study result and this study data will be a great help to plan and carry out an effective prevention program about WMSDs.

• Korean Journal of Rural Living Science
• /
• v.8 no.2
• /
• pp.111-117
• /
• 1997

In this study we tried to give a decision on propriety of working conditions, to present ideas on reducing work loads. and to grope for efficiency of agricultural works. For this we examined the actual conditions of working environment, farmer's clothes, working posture, working methods, working time, resting state, fatigue recovery methods during cultivating lettuce in the winter greenhouse. And Ive improved harmful factors that affect farmer's health by considering results of previous study and farmer's subjective sensation. And we measured, compared, and analyzed the farmer's work loads before and after improvement. The results of this study are as follows ; 1. According to examine the actual conditions of cultivating lettuce in the winter greenhouse, farmers have experienced physical and mental chronic fatigue on the basis of the hot and humid crops-centered working environment, the rough ground condition, inconsistent arrangement of working stand and sorter, heavy-weared habits. and unsuitable working posture. 2. When we improved harmful factors that affect farmer's health, conformed the positive effects on important work efficiency index such as heart rate, electromyovolume, body temperature, and microclimate inside clothing and work loads were decreased by improving the hot and humid working environment, eliminating the hillock and obstacles of working path. deliver way, arranging the working stand and sorter consistantly, decreasing the clothing weight, improving the working postures and methods as using assistant appliances, alloting the working time and sequence effectively and presenting the light gymnastic exercises and rest for fatigue restoration.

• Journal of Korean Society of Rural Planning
• /
• v.13 no.1 s.34
• /
• pp.85-95
• /
• 2007

Hot springs development will be more activated with the five-day work week system than before. Nevertheless, investment and development achievement of hot springs has not resulted in a successful performance to foster townships, and this calls upon locals to build a guideline to develop hot springs. This study intends to analyze laws on hot springs, which influence mostly on the hot spring development, to gather up the information on the present state of the development, and to suggest considerations for further development plans. Features of the hot spring development are as follows: One is that metropolitan cities will discover hot spring resources more than small cities. Therefore the development will be twofold : one for resort tour and the other for one-day rest and recreation. In addition, Korean laws on hot springs are more site development-oriented to support tourism and recreation than to protect environment and discover unused resources. This makes hot spring development easier and efficient being supported by hot spring law, law on territory development and use, and tourism promotion law. On the other side, planned landscape trimming can be uniformized and unharmonized in terms of local identity and environment-friendliness. This is why careful considerations such as goods and bads of the local resources, local history and culture are needed in hot spring development. A long-term development project should include remodeling based on local identity and development trends. The third point indicates that Korean hot springs development has recorded relatively low performance due to difficult private capital attraction, and a high fence on land purchase and development approval. It is essential to release restrictions on the hot spring development-especially on those whose development performance has not been successful so that best practice can be supported by the government in remodeling and marketing. New plans on hot spring development should be also examined based on developer's capacity and local authorities' volition on the plan. Last point shows that most hot springs development plans have been designed only based on territory utilizing plan and facilities arrangement, not considering much on fund-raising, operational plan or feasibility analysis. Therefore the tourism promotion law should reinforce guidelines on tourist site approval system by supplementing criteria. At the same time, an education on tourism development planning is necessary to deepen developers' understanding, since most developers are experts more on city development, landscape architecture, designing, constructing and engineering than tourism development.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.219-220
• /
• 2006

Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance for mold parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser surface hardening for the case of SKD61 steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide surface hardening area with a uniform hardness. From the results of the experiments, it has been shown that the maximum hardness is approximatly 740 Hv when the power, focal position and the travel of laser are 1,095 W, +1mm and 0.3 m/min, respectively. In addition, the hardening width using the elliptical lens was three time larger than that using the defocusing of laser beam.