• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.434-441
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• 2014

This study is purposed to measure airborne asbestos concentrations at demolition sites and surrounding areas of asbestos containing buildings in Seoul and examine whether the measurement results correspond with allowable exhaust standard for asbestos of the Asbestos Safety Control Act. The airborne asbestos concentrations for 37 sites were below the detection limit ($7fiber/mm^2$) in 101 (35%) out of 288 samples. The whole average airborne asbestos concentration in 37 sites was $0.003{\pm}0.002f/cc$(max 0.0013 f/cc) and almost the whole airborne asbestos concentrations were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act. So possibility of asbestos exposure is not yet a major concern at current levels for sites demolished of asbestos containing buildings in Seoul. Looking at each sampling point, the average airborne asbestos concentrations in boundary line of site, entrance of sanitation, around the workplace (in), around the workplace (out), negative pressure units, storage area for waste, outlet for waste and residential area of residents were respectively $0.002{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.005{\pm}0.004f/cc$, $0.005{\pm}0.003f/cc$ and $0.003{\pm}0.002f/cc$. As a result, all sampling points of study were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.1
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• pp.100-109
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• 1993

This study was performed to evaluate the asbestos exposure levels and variations in textile, brake lining manufacturing and slate manufacturing industries. For this study, fifteen plants of brake lining manufacturing industry, 7 plants of textile industry, and 2 plants of slate manufacturing industry were selected and surveyed. Geometric means (GMs) of airborne asbestos concentrations in textile, brake lining manufacturing, and slate manufacturing industries were 1.42 f/cc(0.07-6.1O f/cc), 0.19 f/cc(<0.01-2.67 f/cc) and 0.08 f/cc(0.02-0.67 f/cc), respectively. In textile industry overall GMs of airborne asbestos concentrations in plants with less than 50 workers and in plants with more than 50 workers were 1.60 f/cc and 0.3 f/cc, respectively. Therefore, the size of plant showed some difference in the airborne asbestos concentrations. Three out of 7(42.9%) exceed the Korean standard, 2 f/cc, and every plant exceed the USA standard, 0.2 f/cc of the OSHA-Permissible Exposure Level(OSHA-PEL). Especially, one plant showed the highest average concentration of 2.87 f/cc. In brake lining manufacturing industry, the plants with less than 50 workers showed 0.22 f/cc. The plants with more than 50 workers showed 0.18 f/cc. All plants showed the exposure level below the Korean standard. Five of 15 (33.3%) were above the OSHA-PEL. One plant showed the highest average concentraton of 0.84 f/cc. In slate manufacturing industry, the average exposure level was 0.08 f/cc, and all of the plants were below the Korean standard and the OSHA-PEL.

• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.265-278
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• 1986

This study was attempted to improve the thermal efficiency of 6 kW water-cooled diesel engine on power tiller. The engine performance tests were conducted to find out the effect of cooling water capacity of 2700cc, 2800cc, 2900cc, 3000cc, 3100cc on power, brake specific fuel consumption (BSFC), torque, temperature of cooling water and lubricating oil and friction losses of the engine with D. C. dynamometer. The results obtained in the study are summarized as follows: 1. The performance of the engine tested was adequated to Korea Industrial Standard but actual economy power was 10% higher than the labeled rated power of the engine. The BSFC of the engine tested 297.8g/kW-h which is belong a little higher level than hreign products. The temperature of cooling water was $101^{\circ}C$ which is higher than SAE standard ($88^{\circ}C$) 2. The friction losses of engine tested was 3.656 kW at 2200 rpm of rated rpm (piston speed 6.97m/sec) and is higher than those of foreign products. 3. When the cooling water capacity was increased from 2700cc to 3100cc the power output of the engine was increased from 6.7 kW to 7.13 kW at the rate of 6.4% and also the torque of the engine was increased from 28.85 N.m to 30.76 N.m at the rate of 6.39%. 4. When the cooling water capacity was increased from 2700cc to 3100cc, the BSFC was decreased 6.9g/kW-h from 310.9g/kW-h to 304.1g/kW-h, and after one half hour operation with full load, the temperature of cooling water was decreased $13^{\circ}C$ from $101^{\circ}C$ to $88^{\circ}C$ and also the temperature of lubricant oil was decreased $6.4^{\circ}C$ from $76.7^{\circ}C$ to $70.4^{\circ}C$. 5. The mechanical efficiency was increased from 70.08% to 71.08% when the cooling water capacity was increased from 2700cc to 3100cc.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.5 s.335
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• pp.47-54
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• 2005

In this paper, novel test patterns and on-chip data are presented to indicate that the variation of coupling capacitance, ${\Delta}Cc$ by crosstalk can be larger than static coupling capacitance, Cc. It is also shown that ${\Delta}Cc$ is strongly dependent on the phase of aggressive lines. for anti-phase crosstalk ${\Delta}Cc$ is always larger than Cc while for in-phase crosstalk ${\Delta}Cc$ is smaller than Cc. HSPICE simulation shows good agreement with the measurement data.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.539-542
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• 2005

In the ubiquitous computing environment, service providers should able to deliver their services to various devices, such as PDA Smart Phone, Telematics devices. For this, W3C announced 'Composite Capabilities/Preference Profile (CC/PP) Standard' for delivery-context description. But at present, only a small number of mobile phone supports the CC/PP standard, most of contents servers do not support the CC/PP profiles. In this paper, a rule-based CC/PP profiling method in ubiquitous environment is developed. A rule-based profiles are generated by analyzing request headers which are received from various ubiquitous devices. Service providers can use these profiles to provide optimized services to the various devices which have different capabilities.

• Journal of Environmental Health Sciences
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• v.15 no.1
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• pp.19-32
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• 1989

This study was performed to evaluate the worker exposure to asbestos fibers in automobile repair shop and brake lining store from August 11 to October 21, 1988. In addition, the exposure of general population near the brake lining store was also evaluated. Results of this study were as follows. 1. Worker exposure level to asbestos fibers in automobile repair shop was 0.1 fibers/cc, well below the Korean standard of 2 fibers/cc, and a half of the U.S. standard of 0.2 fibers/cc. 2. Average worker exposure level to asbestos fibers in brake lining store was 0.35 fibers/cc, which was within the Korean standard of 2 fibers/cc, but exceeded the U.S. standard of 0.2 fibers/cc. 3. Worker exposure levels during the removal of brake dust with the compressed air blowing and the dry brushing were approximately 4 fibers/cc and 0.2 fibers/cc, respectively. During grinding of brake linings with sand paper, asbestos exposure level was 0.3 fibers/cc. 4. Ambient asbestos concentrations outside the brake lining store were 0.1 fibers/cc at the distance of 3-4 m, and 0.01 fibers/cc at the distance of 30 m.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.4
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• pp.437-443
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• 2005

Quality characteristic of Kipfel cookies with 0, 20, 40 and $60\%$ of freeze dried chitosan-chungkukjang(CC), which was fermented for 24 hours at $40^{\circ}C$ with steamed soybean added with $0.25\%$ of chitosan(MW 2,025 kDa) powder and inoculated $2\%$ of Bacillus lichenifomis, were investigated Bulk density was higher in the CC cookie, but there were no difference among the CC cookies. While hardness was decreased, brittleness and springiness were increased in the higher ratio of CC, but no significant difference was observed in cohesiveness and gumminess. According to increasing the CC ratio, L$\ast$ values and hue angle were decreased from 62.69 and 96.71 to 44.41 and 69.30, respectively. While a$\ast$ values were increased from -1.94 to 4.95, and no changes were observed in b$\ast$ values. Glucosamine content was $27.34 mg\%$ in the control cookie, $40{\~}93.75 mg\%$ in the CC cookies. Antioxidant activity of the CC cookies were higher than the control. The activity of the control cookie was decreased during storage, while it was maintained in CC cookies. There were no differences in the sour, sweet and savory taste. Off-flavor did not detected in the $0{\~}40\%$ CC cookies, but the chungkukjang odor was slightly detected in the $60\%$ CC cookie. The $20{\~}40\%$ CC cookies did not affect on native odor of Kipfel cookie. Color acceptability also did not affect by addition of CC $20{\~}40\%$ but it was lower in $60\%$ CC cookie. Overall acceptability was the best in the $20\%$ CC cookie.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.149-157
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• 2004

We have calculated the power extraction efficiency and the lasing wavelength distribution of complex-coupled(CC) DFB lasers above threshold for various｜$\chi$L｜ and facet reflectivity combinations, and we have compared the results with those at threshold. Also, we have investigated the effect of coupling coefficient ratio(CR) and the reflectivity of AR facet on the power extraction efficiency and the lasing wavelength distribution. At threshold, the single mode yield as a function of power extraction efficiency of in-phase(IP) CC DFB lasers is the same as that of anti-phase(AP) CC DFB lasers. Above threshold, however, the single mode yield as a function of power extraction efficiency of IP CC DFB lasers is much larger than that of AP CC DFB lasers. For IP CC DFB lasers, AR-HR combination has high single mode yield and large power extraction efficiency compared to other facet combinations. IP CC DFB laser with AR-HR combination for ｜$\chi$L｜of 0.8 has the highest single mode yield and largest power extraction efficiency above threshold among the cases considered. For AR-HR combination, as CR increases and the reflectivity of AR facet decreases, both single mode yield and power extraction efficiency increase due to the reduction of the spatial hole burning effect. For AR-HR combination, the lasing wavelength of CC DFB laser has distributed over the stopband of DFB. As CR increases, the lasing wavelength concentrates on the long wavelength side for IP CC DFB laser, while on the short wavelength side for AP CC DFB laser. As ｜$\chi$L｜ increases, the width of the wavelength distribution decreases and the lasing wavelength moves to the long wavelength side.

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.2
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• pp.109-113
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• 2008

Purpose: To evaluate the detector dependency in the various collimator size for Stereotactic Radiosugery (SRS). Materials and Methods: This study was performed with 6 MV photon beam (Varian 21EX, Varian, US) and the measurement detectors are used by ion chamber CC01, CC13 (Wellhofer, Germany) and stereotactic diode detector (SFD, Wellhofer, Germany). SRS collimator size was used by ${\varphi}$5, 10, 20, 30 mm (Brain Lab, Germany). Percentage depth dose (PDD) was measured at SSD 100 cm and field size 10×10 cm from individual detectors. Ouput factor was measured by using same setup of PDD and with maximum dose depth. Data was normalized at field size $10{\times}10\;cm$. Beam profile was measured at SSD 100 cm in SRS collimator ${\varphi}$10, 30 mm and field $10{\times}10\;cm$ and a comparison of FWHM (full width half maximum), penumbra width (20~80%). Results: The CC13 detector was overestimated 16% than other detectors from the PDD in the 5 mm collimator. Output factors were underestimated CC01 28%, CC13 72% in the 5 mm collimator and CC01 9.6%, CC13 25% in the 10 mm collimator than the SFD. Maximum difference was 3% at the FWHM of the dose profile in the 10 mm collimator and difference of the 30 mm collimator was 0% at the FWHM. Penumbra width was increased CC01 122%, CC13 194% in the 10 mm collimator and CC01 68%, CC13 185% in the 30 mm collimator than the SFD. Conclusion: It is very important for accurate dosimetry to select a detector in small field. The SFD was considered with the most accurate dosimeter for small collimator dosimetry in this study.

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.13-17
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• 2015

In superconducting coil applications particularly in wet wound coils, coated conductor (CC) tapes are subjected to different type of stresses. These include hoop stress acting along the length of the CC tape and the Lorentz force acting perpendicular to the CC tape's surface. Since the latter is commonly associated with delamination problem of multi-layered CC tapes, more understanding and attention on the delamination phenomena induced in the case of coil applications are needed. Difference on the coefficient of thermal expansion (CTE) of each constituent layer of the CC tape, the bobbin, and the impregnating materials is the main causes of delamination in CC tapes when subjected to thermal cycling. The CC tape might also experience cyclic loading due to the energizing scheme (on - off) during operation. In the design of degradation-free superconducting coils, therefore, characterization of the delamination behaviors including mechanism and strength in REBCO CC tapes becomes critical. In this study, transverse tensile tests were conducted under different loading conditions using different size of upper anvils on the GdBCO CC tapes. The mechanical and electromechanical delamination strength behaviors of the CC tapes under transverse tensile loading were examined and a two-parameter Weibull distribution analysis was conducted in statistical aspects. As a result, the CC tape showed similar range of mechanical delamination strength regardless of cross-head speed adopted. On the other hand, cyclic loading might have affected the CC tape in both upper anvil sizes adopted.