• 한국농공학회지
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• 제44권2호
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• pp.136-147
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• 2002

Characteristics of unit loads of pollutants were investigated at a paddy fields area(Soro-ri) with large-scaled plots on loam soil during irrigation seasons of 1999 ∼2000. The average irrigation requirement of experimental paddy area are estimated at over 3,000 mm. The unit loads of pollutants in paddy fields area are determined by subtracting irrigation water load from outflow load (percolated and surface outflow loads). Surface outflow load in rainy days was calculated using the relationships of discharge and load, which are grouped into fertilizing and non-fertilizing periods. The ratios of the surface outflow load in rainy days to the total surface outflow load are 16.4% for T-N, 26.8% for T-P, and 23.3% far CODc,. The unit loads of pollutants show month-to-month and year-to-year variations, and monthly unit load of pollutants can show negative values, indicating that the paddy area acts as the pollutants sink. The average unit loads of the pollutants during irrigation seasons were estimated at 18.2 kg/ha fur T-N, 0.31 kg/ha for T-P, and 43.3 kg/ha for CODc,, which are smaller than the reported values for Kosei area in Japan.

• ETRI Journal
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• 제28권4호
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• pp.506-508
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• 2006

A frequency selective surface (FSS), whose unit cell consists of a ternary tree loop loaded with a modified tripole, is proposed to block multiple frequency bands. Target frequency bands correspond to Korean personal communication services, cellular mobile communication, and 2.4 GHz industrial, scientific, and medical bands. Through the adjustment of inter-element and inter-unit cell gaps, and adjustment of the length of elements, we present an FSS design method that makes the precise tuning of multiple resonance frequencies possible. Additionally, to verify the validity of our approach, simulation results obtained from a commercial software tool and experimental data are also presented.

• International journal of advanced smart convergence
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• 제12권3호
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• pp.211-220
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• 2023

Surface electromyography (sEMG) is a noninvasive method used to capture electrically muscle activity, which can be easily measured even during exercise. The basic unit of muscle activity is the motor unit, and because an sEMG signal is a superposition of motor unit action potentials, analysis of muscle activity using sEMG should ideally be done from the perspective of motor unit activity. However, conventional techniques can only evaluate sEMG signals based on abstract signal features, such as root-mean-square (RMS) and mean-power-frequency (MPF), and cannot detect individual motor unit activities from an sEMG signal. On the other hand, needle EMG can only capture the activity of a few local motor units, making it extremely difficult to grasp the activity of the entire muscle. Therefore, in this study, a method to visualize the activities of motor units in a single-channel sEMG signal by relocating wavelet coefficients obtained by redundant discrete wavelet analysis is proposed. The information obtained through this method resides in between the information obtained through needle EMG and the information obtained through sEMG using conventional techniques.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 춘계학술대회 논문집
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• pp.1-8
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• 1995

This paper proposed a simple method for measuring surface roughness of ground surface. utilizing non-contact in-process measuring system using the diode laser. The measurement system is consisted of a laser unit with a diode laser and a cylindrical lens a detecting unit with polygon mirror and CCD array sensor. and a signal processing unit with a computer and device. During operation, this measuring system can provide information on surface roughness in the measuring distance with a single sampling and simultanilusly monitor the state of the grind wheel. The experimental results, showed that the increase of the feed rate and the dressing speed an caused increase in the surface roughness and when the surface roughness is 4Rmax-10Rmax, the cutting speed is 1653m/min-1665m/min. the feed rate is 0.2m/min-0.9m/min, the dressing speed is 0.2mm/rev-0.4mm/rev, the stylus method and the in-process method can be obtained the same results. thus under limited working conditions. using the proposed system. the surface roughness of the ground surface during cylindrical grinding can be obtained through the in-process measurement method using the diode laser.

• 대한치과의료관리학회지
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• 제11권1호
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• pp.38-46
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• 2023

Composite resins, commonly used in clinical practice, have been developed to improve aesthetics to obtain smooth surfaces. Although the restored composite resin has a smooth surface, it gradually becomes rough over time. Therefore, this study measured glossiness to evaluate the surface of various composite resins and attempted to evaluate the maintenance of glossiness of composite resins by observing surfaces that change to roughness. Specimens were produced using resin used in clinical practice: Gradia direct anterior (GA), Tetric N-Ceram (TN), Ceram.X Sphere TEC one (CX), Filtek Z350XT (FT), Estelite sigma quick (ES). After creating a smooth surface with slide glass, five locations were randomly selected to measure surface gloss, and the average was the representative value of the specimen. Roughness was applied to the specimen under water pouring at the same speed and pressure using SiC paper #2400, 1200, and 400. The gloss unit of different SiC papers was measured. To evaluate the gloss unit and gloss retention between composite resins, one-way analysis of variance and Tukey multiple comparisons test were used. As a result of the study, there was a difference in gloss unit of specimens produced under the same conditions. Although the degree differed depending on the composite resin, there was also a difference in gloss retention. Based on the findings, composite resins show differences in gloss due to their different characteristics. Ceram.X Sphere TEC one (CX) showing the lowest gloss retention and Estelite sigma quick (ES) showing the highest.

• 한국안전학회지
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• 제10권3호
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• pp.30-41
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• 1995

This paper proposed a simple method for measuring surface roughness of ground surface. Utilizing non-contact in-process measuring system using the diode laser. The measurement system is consisted of a laser unit with a diode laser and a cylindrical lens, a detecting unit with polygon mirror and CCD array sensor, and a signal processing unit with a computer and device. During operation, this measuring system can provide information on surface roughness in the measuring distance with a single sampling and simultaniously monitor the state of the grind wheel. The experimental results, showed that the Increase of the feed rate and the dressing speed an caused increase in the surface roughness and when the surface roughness is 4Rmax-10Rmax, the cutting speed is 1653m/min-1665m/min, the table speed is 0.2n1/min -0.9m/min, the dressing speed is 0.2mm/rev～0.4mm/rev, the stylus method and the in-process method can be obtained the same results. Thus, under limited working conditions, using the proposed system, the surface roughness of the ground surface during cylindrical grinding can be obtained through the in-process measurement method using the diode laser.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.67-70
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• 2003

To develop an effective geometric modeling is essential in order that precise mechanical properties and the geometrical properties of the 3-D braided composites can be estimated. RVE(representative volume element) was adopted fur geometrical modeling. RVE consisted of IC(inner unit cell), ISUC(interior surface unit cell) and ESUC(exterior surface unit cell). The whole geometrical model fur hybrid 3-D braided composites was developed.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.385-388
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• 2002

We investigated net outflow load and unit load of pollutants from a paddy fields area in dry year 2001. Amount of irrigation water in 2001 was about 61-63% of that in previous years 1999 and 2000 due to drought. The net outflow load and unit load of pollutants in 2001 were negative, showing that paddy fields acts as sink of pollutants due to function of water quality purification. The relationship between unit load of pollutants and net surface outflow (= surface outflow - irrigation water) showed positive correlation. The results showed that abatement of surface outflow by appropriate water management contribute to reduce surface outflow load from paddy fields.

• 한국정밀공학회지
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• 제18권2호
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• pp.90-95
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• 2001

f-$\theta$len is one of the important parts in Laser Scanning Unit because it affects on the optical performance of Laser Scanning Unit dominantly. It is necessary to find out the relationship between the surface profile error of f-$\theta$lens and the beam profile focusing on the Organic Photo Conductive drum in order to analysis the beam profile problems such as appearance of side lobe and expansion of center lobe. In this research, a simulation process which relates the surface profile characteristics to the beam profile has been developed by CODE V. The simulated beam profile also have been compared with the measurement results.

• 한국환경복원기술학회지
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• 제4권3호
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• pp.1-9
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• 2001

The purpose of this study was to evaluate the burning impacts of the surface and crown fire occured in yongsan-ri meongsok-myun of chinju-city, Gyeongnam. Environmental influences like surface runoff and soil erosion changes were investigated by comparisons analysis between burned and unburned area about some initial effects after fire. The results obtained from this study were as followed; 1. The average amount of surface runoff in burned area was more 1.7 times than in unburned area. But it was gradually tend to decrease in burned area as times passed. 2. Factors significantly correlated to amount of surface runoff in burned area shown in order to unit rainfall, accumulated rainfall and sand content, as 0.9466 of multiple correlation coefficient, where as the factors in unburned area were unit rainfall, soil erosion, bulk density and soil hardness, as 0.9738 of multiple correlation coefficient. 3. The average amount of soil erosion in burned area was more 11.2 times than in unburned area. But it was gradually tend to decrease in burned area as times passed. 4. Factors significantly correlated to amount of soil erosion in burned area were surface runoff and unit rainfall, as 0.6305 of multiple correlation coefficient. The factors in unburned area shown in order to surface runoff, sand content, bulk density and unit rainfall, as 0.7879 of multiple correlation coefficient.