• 한국토양비료학회지
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• 제34권3호
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• pp.147-152
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• 2001

This study was carried out to investigate the effect of application time and amount of liquid pig manure on growth and yield of rice plant and infiltration water quality. Liquid manure treatment with higher application rate and closer application time to transplanting time showed higher plant height and number of tiller at panicle formation stage, but it caused the plant disease and pest and lodging. In liquid manure treatment with higher application rate, number of panicles per hill and number of spikelets per panicle were higher but yield of rice was less than chemical fertilizer treatment due to low rate of ripeness and 1,000 grain weight. $NO_3-N$ concentration in infiltration water sample was increased with increasing application amount of liquid manure and closer application time to transplanting of rice plant. With consideration yield of rice and environment such as groundwater quality, the proper application amount were 150% and 100% of recommending N fertilizer level (11kg) at before winter and April or May treatment, respectively.

• Korean Chemical Engineering Research
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• 제46권2호
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• pp.430-435
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• 2008

상황버섯(Phellinus linteus) 균사체로부터 얻어지는 다당류를 최대화하기 위하여 투석시간(8, 16, 24, 48 h)을 포함하는 추출조건과 정제조건이 다당류의 양에 미치는 영향에 대해 연구하였다. 추출온도(50, 65, 80, $95^{\circ}C$)와 건조 균사체의 무게에 대한 물의 부피의 비(10, 15, 20, 25 ml/g), 추출시간(2, 4, 6, 8 h), 에탄올의 최종 농도(70, 75, 80, 85%) 그리고 묵힘시간(1, 4, 8, 16 h)이 증가할수록 다당류의 양은 증가하였다. 투석시간이 24 h까지 증가할수록 다당류의 양은 감소하였으나 그 이상의 투석시간은 다당류의 양을 거의 변화시키지 못했다. 침전용매로는 3가지 용매(에탄올, 메탄올, 아세톤)를 사용하였는데, 다당류의 양은 아세톤, 에탄올, 메탄올의 순서로 감소하였다. 최적 추출조건은 추출온도가 $95^{\circ}C$이고, 건조 균사체의 무게에 대한 물의 부피의 비가 25 ml/g이며, 추출시간은 8 h인 조건이었다.

• 가정과삶의질연구
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• 제14권4호
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• pp.145-162
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• 1996

The purpose of this study was to compare time use pattern of Korean working couples with those of Japanese counterparts. The data for240 Korean couples living in Seoul and 162 Japanese couples living in Tokyo were collected using structured questionnaire and time diary. The time use patterns of couples were analyzed according to employed status of wives. The results were as follows. The similar time use patterns were found between couples of two country. However the amount of time allocated for daily activities was found to be somewhat different. The amount of time spent by husbands on paid and house work was found to be different according to their wives employment status. The orean husbands of full-time employed wives and the Japanese husbands of part time employed wives spent the longest time on paid work. The Japanese husbands of full-time employed wives spent much more time on housework than those of Korean counterparts did. The social-cultural time of Korean couples was enerally longer than that of Japanese couples. The Korean couples spent more time on watching TV whereas the Japanese couples used more time doing family activities hobbies and moving for social-cultural activities.

• 제어로봇시스템학회논문지
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• 제12권5호
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• pp.457-463
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• 2006

Recently proposed control scheme for a stable teleoperation, which was based on two-port time-domain passivity approach[21], has been successful for a contact with high stiffness environments. However, we found several conservatisms during the contact with deformable environments and unconstrained motion. The two-port time-domain passivity controller was excessively dissipating energy even though it was not necessary for some cases of an unconstrained motion and soft contact. The main reason of those conservatisms was on the fact that the two-port time-domain passivity controller was activated without considering the amount of energy dissipation at the master and slave manipulators. Especially, the exclusion of the slave manipulator from the two-port was the dominant reason of the conservatisms. In this paper, we consider the amount of energy dissipation at slave manipulator for designing the time-domain passivity observer and controller. The measured interaction force between slave manipulator and environment allow the time-domain passivity observer to include the amount of energy dissipation at the slave manipulator. Based on the modified passivity observer, reference energy following method[24] is applied to satisfy the passivity condition in real-time. The feasibility of the developed methods is proved with experiments. Improved performance is obtained for an interaction with deformable environments and an unconstrained motion.

• 대한치과보철학회지
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• 제43권2호
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• pp.258-263
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• 2005

Statement of problem. Implant screw loosening has been remained a problem in implant prosthodontics. The time needed to insert screw driver into abutment screw head should be shortened for the purpose of decreasing the chair time. Purpose. The purpose of this study was to investigate the effects of the design of abutment screw driver on the amount of time for insertion of screw driver into abutment screw head. Material and methods. Hexagonal and rectangular types of abutment screw drivers were used. The original abutment screw drivers were modified by grinding acute angle of the screw driver tip (modified drivers). Group 1 : hexagonal type abutment screw and original driver Group 2 : hexagonal type abutment screw and modified driver Group 3 : rectangular type abutment screw and original driver Group 4 : rectangular type abutment screw and modified driver UCLA lab analogues were located in acrylic resin block. The angulations of them were 0 and 20 degrees. The times needed for insertion were measured. Group 1 and 3 were used as controls. Results. 1. Group 2 showed shorter insertion time than group 1, regardless of implant angulations (p<.05). 2. Group 4 showed shorter insertion time than group 3, regardless of implant angulations (p<.05). Conclusion. Modified abutment screw drivers required less amount of time to insert screw driver into abutment screw head. Modification of abutment screw driver was beneficial.

• 한국세라믹학회지
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• 제26권3호
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• pp.297-304
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• 1989

The dielectric properties of SrTiO3 GBL Capacitor have been investigaetd as a function of the second heat treatment time and the amount of Ta. The grain size of semiconductive SrTiO3 after sintering at 1,46$0^{\circ}C$ for 4 hours in N2/H2 atmosphere increased as the amount of Ta increased, and then decreased as the amount of Ta exceed 0.01 mole. Also, the dielectric constant after the second heat treatment showed the same tendency. When the semiconductive SrTiO2 was second heat treated at 1,10$0^{\circ}C$ in air with varying time, the dielectric constant increased as the second heat treatment time increased up to 60 minutes, and then decreased as the time became longer than 60 minutes.

• 한국기계가공학회지
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• 제14권5호
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• pp.22-27
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• 2015

Processing of low toughness graphite material requires high-speed machine tools and DLC coating. In this study, results of investigation of the tool wear and machining properties of the DLC coating according to the thickness, and the machining time of the tool used for the machining of graphite electrodes, were as follows. 1. DLC coating thickness shows a larger wear amount of the tool center in accordance with thickness; the wear amount of the tool increases in proportion to the machining time. 2. The difference between the amount of wear depending on the processing time shows edge portions larger than the tool wear amount in the center. This amount of wear of the tool edge is formed since the rotating torque is in contact with the graphite material surface significantly more than the central portion. 3. The thicker the DLC coating, the more the coating tool eliminated of the coating area by the interface between the cemented carbide tool being coated with an increased friction of the graphite material and the DLC coating area.

• 산업경영시스템학회지
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• 제44권3호
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• pp.117-124
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• 2021

The development of IOT technology and artificial intelligence technology is promoting the smartization of manufacturing system. In this study, data extracted from acceleration sensor and current sensor were obtained through experiments in the cutting process of SKD11, which is widely used as a material for special mold steel, and the amount of tool wear and product surface roughness were measured. SVR (Support Vector Regression) is applied to predict the roughness of the product surface in real time using the obtained data. SVR, a machine learning technique, is widely used for linear and non-linear prediction using the concept of kernel. In particular, by applying GSVQR (Generalized Support Vector Quantile Regression), overestimation, underestimation, and neutral estimation of product surface roughness are performed and compared. Furthermore, surface roughness is predicted using the linear kernel and the RBF kernel. In terms of accuracy, the results of the RBF kernel are better than those of the linear kernel. Since it is difficult to predict the amount of tool wear in real time, the product surface roughness is predicted with acceleration and current data excluding the amount of tool wear. In terms of accuracy, the results of excluding the amount of tool wear were not significantly different from those including the amount of tool wear.

• 한국식품조리과학회지
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• 제23권4호통권100호
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• pp.433-442
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• 2007

This study was conducted to investigate the quality characteristics of Sulgitteok prepared with different ratios of lotus leaf powder, over for 4 days of storage. As the amount of lotus leaf powder increased, the moisture contents of the lotus leaf Sulgitteok decreased; however, this was not consistent for all samples during storage. As the content of the lotus leaf powder increased, the L-values of the lotus leaf Sulgitteok significantly decreased, and the a- and b-values also significantly increased at day 0. The L- and a-values did not show large differences with storage. The total cell count of the lotus leaf Sulgitteok prepared with the 4% lotus leaf powder (LL4) was considerably lower than the other samples at 2 days of storage, indicating that microorganisms were inhibited by increasing amounts of lotus leaf powder. The hardness, gumminess, and chewiness of the lotus leaf Sulgitteok decreased as the amount of lotus leaf powder increased; however, they increased as storage time passed. Increasing amount of lotus leaf powder and the storage time resulted in greater reductions in adhesiveness. Springiness was not significantly different according to the amount of added lotus leaf powder or the storage time. Increasing storage time caused cohesiveness to decreased in all samples except LL2. Also, the results of the sensory evaluation showed that the LL2 lotus leaf Sulgitteok had the highest scores. In conclusion, the lotus leaf Sulgitteok prepared with the 2% lotus leaf powder (LL2) was superior.

• 산업경영시스템학회지
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• 제17권32호
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• pp.243-253
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• 1994

Work environments have been changed with the advent of new technologies, such as computer technology. The newer technologies, the more changes in our work conditions. However, human cognitive limits can't keep up with the change of work environments. Mental workload has been an important factors in designing modem work environments such as human-computer interaction. Designing man-machine systems requires knowledge and evaluation of the human cognitive processes which control information flow workload. Futhermore, under an urgent situation, human operator may suffer the work stress, work error, and resultant deleterious work performance. To describe the work performance in the urgent work situations, with time stress and dynamic event occurence, a new concept of information density was introduced. For a series of experiments performed for this study, three independent variables(information amount system processing time, information density) were evaluated using such dependent variables as reaction time, number of error, and number of failure. The results of statistical anlysiss indicate that the amount of information effected on all of five dependent measure. Number of failure and number of secondary task score were effected by both amount of information and operational speed of system, but reaction time of secondary task were effected by both amount of information and information density.