• Journal of The Korean Astronomical Society
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• v.11 no.1
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• pp.37-46
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• 1978

A hydrostatic model atmosphere of a typical umbral core is constructed on the basis of both Na I $D_2$ line profile and umbral core-to disk continuum intensity ratio. The observations were obtained by Mullan and Wyller with photoelectric means over the range from $4000{\AA}\;and\;6500{\AA}$. The computed line profile of Na I $D_2$ and the emergent continuum intensity distribution are compared with the observations. The temperature of umbral cores is found to be lower by $300^{\circ}K\;to\;500^{\circ}K$ than that of their ambient umbral region. The detailed physical structure of a working model of umbral cores is proposed.

• Proceedings of the Korean Magnestics Society Conference
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• 2009.12a
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• pp.217-219
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• 2009

A GMI magnetic field sensor working based on time-coded principle has been investigated and designed. The laboratory model has been constructed and tested carefully, demonstrating the sensitivity of $3\;{\mu}s/{\mu}T$ in the field range of ${\pm}100\;{\mu}T$. An amorphous thin wire, $100\;{\mu}m$ in diameter ${\times}50\;mm$ in length, was chosen to be sensing element which was fit into a small field modulation coil of 60 mm in length. The sensor is working based on a time-coded principle that, with the magnetic field modulation was chosen in range of hundreds of Hz, the change in time interval of two adjacent GMI peaks relating to external DC magnetic field is proportional to the intensity of the external field to be measured. This mechanism has made a great improvement to the linearity of the sensor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.31-34
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• 2007

In this study, optimum processing condition of AZ31 Mg alloy was investigated utilizing processing map and constitutive equation considering microstructure evolution (dynamic recrystallization) during hot-working. A series of mechanical tests were conducted at various temperatures and strain rates to construct a processing map and to formulate the recrystallization kinetics and grain size relation. Dynamic recrystallization (DRX) was observed to occur revealing maximum intensity at a domain of $250^{\circ}C$ and 1/s. The effect of DRX kinetics on microstructure evolution was implemented in a commercial FEM code followed by remapping of the state variables. The volume fraction and grain size of deformed part were predicted using a modified FEM code and compared with those of actual hot forged one. A good agreement was observed between the experimental results and predicted ones.

• International Journal of Highway Engineering
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• v.19 no.3
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• pp.83-90
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• 2017

PURPOSES : In this study, systematic road snow-removal capabilities were estimated based on previous historical data for road-snowremoval works. The final results can be used to aid decision-making strategies for cost-effective snow-removal works by regional offices. METHODS : First, road snow-removal historical data from the road snow-removal management system (RSMS), operated by the Ministry of Land, Infrastructure and Transport, were employed to determine specific characteristics of the snow-removal capabilities by region. The actual owned amount and actual used amount of infrastructure were analyzed for the past three years. Second, the regional offices were classified using K-means clustering into groups "close" to one another. Actual used snow-removal infrastructure was determined from the number of snow-removal working days. Finally, the correlation between the de-icing materials used and infrastructure was analyzed. Significant differences were found among the amounts of used infrastructure depending on snowfall intensity for each regional office during the past three years. RESULTS:The results showed that the amount of snow-removal infrastructure used for low heavy-snowfall intensity did not appear to depend on the amount of heavy snowfall, and therefore, high variation is observed in each area. CONCLUSIONS:This implies that the final analysis results will be useful when making decisions on snow-removal works.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.10-17
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• 2001

We need to how about activity types, lighting conditions and physical features in a plate that is a object for the reasonable and economic lighting design. Thus, lighting designer analyzes spare features and completes lighting design by using luminaire that has a suitable luminous intensity distribution. There are special data in this study from analysing about activity types, lighting conditions and physical features of intelligent buildings that are getting an essential infrastructure in the information society. Intelligent building could be classified with office space, passing space, high ceiling space, one-side working space for the analysis. Also, four luminous intensity distributions and fluorescent fixtures, which are the mutt used luminaires in office building, are designed from the data of intelligent building.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.579-581
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• 2011

Spectroscopic evaluation of hair chemical damage was performed by SEM/EDS, CLSM, and FT-IR spectroscopy. In SEM/EDS, hydrogen peroxide treated hair showed the loose packing of surface scales, lower ratio of sulfur element and higher ratio of oxygen atom. In the optical single section by using CLSM, high fluorescent intensity appeared in untreated hair. However, in case of treated hair, low fluorescent intensity appeared. This results the aromatic amino acids which can be autofluorescent were more abundant than bleached hair. FT-IR spectra showed that cysteic acid band intensity was increased by performing the bleaching treatments. These results indicate that the oxidative damage cleaves the S-S bond and results in the lower working force of hair fiber.

• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.88-96
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• 2022

Widespread infectious diseases are a concern for workers working in confined spaces. However, there is no risk assessment index for the risk of infectious disease in the workplace. Therefore, we propose a simple but effective index model to assess the risk of infectious diseases in the workplace. The proposed model identifies the risk of each workplace through an evaluation sheet comprising the frequency and intensity of the infectious disease. The intensity of an infectious disease is generally governed by the density of workers, whereas frequency is the sum of physical-e nvironmental and human management factors. By multiplying intensity and frequency, the risk of the workplace is derived. Through the proposed model, we evaluate the risks of workers at 15 different work sites. The proposed model clearly reveals what should be improved to keep workers safe from infectious diseases and will be helpful in assessing the risk of contagious disease at the work place.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1254-1260
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• 2000

There have been many developments in super precision working technique and working method up to, now. But, it is very difficult to evaluate working surface accurately without the technicians experience and judgment. Surface roughness tester using stylus was used to measure surface condition generally But this method is not so desirable because of damage on test piece caused by contact between the workpiece and the stylus sensor. As a result, non-contact method was known as a good way to carry, out this process without damage. However, this is a difficult one among the various measuring methods. So we are tying to suggest a new method using texture analysis through image processing to get a surface information in worked test piece. Co-occurrence matrix using difference of gray levels between a pixel and its neighboring one was used to study behavior of surface roughness and to J acquire data for analysis. Standard specimen was adapted to verify this research. We suggest texture information method in order to evaluate surface state for the best measurement system.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.416-422
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• 2007

The application analysis of bubble pump on the domestic solar water heater system is presented. The system investigated in this study is a passive device, self pumping and self regulating. It was test to use the bubble pump on solar water heater system. The test experiment has been taken on the existed vacuum tube about the efficiency, working fluid temperature and pressure and circulated power. In order to check the working temperature and working pressure effectively, the bubble pump was test separated from the solar water heater. The equipment consists of the bubble pump, heater and heat exchanger. The main structure of bubble pump was design depend on the character of two phase flow. The complete system was instrumented to measure pressures, temperatures and their relationship with the solar radiation intensity. The theory analysis of design bubble pump has been given and the experiment result analysis has been included in the paper.

• Journal of Agricultural Extension & Community Development
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• v.18 no.4
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• pp.861-877
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• 2011

The purpose of this study is to survey job stress and Musculoskeletal Disorder(MSDs) of workers in small plants with agricultural products. The subjects were comprised of 69 workers participated in "Helping the rural women to get the small businesses" project. The questionnaire surveys were Korean Occupational Stress Scale(KOSS), and Legal Risk Assessment of Musculoskeletal Disorders(KOSHA CODE H-30-2003). As a result of the survey, scores of KOSS 8 sub-items except for job demand were similar to that of Korea workers. Prevalence of MSDs symptoms of small plants workers was high percent (44.9%). And the rate according to kinds of product was significant difference at neck (p<0.01), lumbar (p<0.01), and leg (p<0.01). There was no significant difference between view person sign of MSDs and non MSDs according to sex, year, the number of workers, working years, working time per one day, rest time per one day, and subjective working intensity, but there were significant difference between high stress group and low stress group about MSDs at interpersonal conflict(p<0.05). Job stress and MSDs were important factor to workers of small plants producted agricultural products. Therefore, starting a business with small plats, workers consider interpersonal conflict and body part showing MSDs.