• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.14-20
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• 2008

An agricultural unmanned helicopter was suggested for an alternative to current pesticide application methods to solve such problems as high cost, low efficiency, shirking task and unsafe work. To pursuit this trend, researches on the development of unmanned helicopters have been accelerated in Korea as well. In this research, a guide type centrifugal clutch that plays an important role in the unmanned helicopter was studied. Theoretical analyses and experimental tests were conducted for designing an optimal clutches. Main design factors of the guide type centrifugal clutch were found to be spring constant, free length of spring, mass of friction sector, contact area, allowable pressure, number of friction sector, friction coefficient, radius of drum, and clutch arrangement. And these design factors could be the functions of engaging engine speed and desired power transfer capacity. The result of the single clutch test showed the power transfer capacity of 14.1 PS at 5,800 rpm and the result of the dual clutch test showed that the capacity of 17.7 PS at 5,600 rpm. These experimental results agreed well the theoretical simulations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.833-836
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• 2000

The mechanical and thermal load. and thermal softening which is happened by the high temperature of die, in hot and warm forging, cause wear. heat checking and plastic deformation, etc. This study is for the effects of solid lubricants and surface treatments for warm forging die Because cooling effect and low friction are essential to the long lift of dies. optimal surface treatments and lubricants are very important to hot and warm forging Process. The heat that is generated by repeated forging processes. and its transfer are important factors to affect die life. The main factors, which affect die hardness and heat transfer, are surface treatments and lubricants, which are related to thermal diffusion coefficient and heat transfer coefficient, etc. For verifying these. experiments art performed for diffusion coefficient and heat transfer coefficient in various conditions - different initial billet temperatures and different loads. Carbonitriding and ionitriding are used as surface treatments. and oil- base and water-base graphite lubrirants are used. The effects of lubricant and surface treatment for warm forging die lift are explained by their thermal characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.341-346
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• 2006

Despite many studies, results of superovulation protocols are not consistent in farm animals. In this study, 151 Boer goats were superovulated to examine the factors affecting superovulation and embryo transfer (MOET). An optimal regime for superovulation treatment was identified as a 4-day treatment with decreasing dosages of 6-7 mg Chinese FSH or 240 mg Canadian FSH. The 4-day treatment with decreasing dosages of 6-7 mg Chinese FSH was, therefore, adopted to study effects of the age of does, season and repeated treatments on superovulation and embryo transfer. The best season for superovulation and embryo transfer and pregnancy was autumn, and the best age range was 12-35 months old. Within animals there were no significant differences in the number of ovulations and the rate of transferable embryos between the first and the second superovulation. However, these parameters declined significantly for the third superovulation. No marked effects of the number of ovulations on the proportion of transferable embryos were noted. The parturition rate of the recipients receiving single embryos was not different significantly from those receiving two embryos, and the kidding rate calculated from embryos transferred did not differ significantly between recipients receiving one and two embryos.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.10
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• pp.2657-2666
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• 1995

In this study, the effects of design factors of finned-tube heat exchanger, such as fin spacing and fin array on the frost growth and heat exchanger performance are investigated under a frosting condition. The results show that the amount of frost, frost density and blockage ratio of air flow passage increase with decreasing fin spacing. Heat transfer rate increases momentarily at the initial stage of frosting and then decreases. After that heat transfer rate continues to increase again to reach a maximum value and then decreases dramatically. It is shown that the time required for heat transfer rate to reach a maximum value becomes shorter with decreasing fin spacing, and after a maximum value, heat transfer rate decreases very fast. The maximum allowable blockage ratio is introduced to determine the operation limit of a finned-tube heat exchanger operating under frosting condition and is obtained as a function of fin spacing. It is also shown that heat transfer rate of heat exchanger with staggered fin array increases about 17% and the amount of pressure drop of air increases about 1~2 mmH$_{2}$O, compared with those of in-line type heat exchanger under frosting condition.

• Journal of Agricultural Extension & Community Development
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• v.23 no.3
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• pp.233-242
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• 2016

This study aimed to analyze educational satisfaction and the relationship between learning transfer and learning persistence shown after actual education targeting students who participated in the agricultural education and training. Conclusions based on the study results can be suggested as follows. First, of the factors related to learning persistence, satisfaction of educational contents turned out to be a statistically significant factor with a positive effect in the agricultural education and training. Students participating in the agricultural education and training have a conspicuous object to learn for improving ability which is necessary for and applicable to agriculture. Second, of the three factors related to learning transfer in the agricultural education and training, satisfaction of educational contents, educational facilities and satisfaction of environment turned out to have a positive effect. Third, results show that satisfaction of instructors does not affect both learning persistence and learning transfer. Lastly, in case of education and training for field practice, this study is suggesting the necessity of research by accessing in a concrete and detailed manner such as learning contents, instructors, educational facilities and satisfaction of environment from the comprehensive concept of educational satisfaction in the directivity of study related to satisfaction.

• Journal of Korean Society of Archives and Records Management
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• v.18 no.3
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• pp.71-95
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• 2018

This study aims to analyze the factors affecting the transfer effect of continuing education in the National Archives of Korea and suggest ways to improve the education. To do that, the study grouped the factors that affect the transfer effect of continuing education into learner characteristics, educational program characteristics, and organizational transition climate. An online survey was conducted with records managers. In total, 272 responses were received and statistically analyzed. Based on the records managers' opinions, this study suggested ways to improve the transfer effect of continuing education from the perspectives of learners, the educational program, the organizational transition climate, and the roles of the National Archives of Korea.

• Journal of Korea Technology Innovation Society
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• v.22 no.2
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• pp.159-185
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• 2019

Chemical industry, as one of the basis industries of the country, is characterized by converged high-end technology and large scale capital investment. In 2018, the government announced "The Strategy for Chemical Industry Development" with the vision of 'An Upgrade to the Advanced Chemical Industry'. In the meantime, the advanced chemical industry in Korea has been developed not by its own R&D, but by the upgrading of technologies and processes through the technology transfer from developed countries. The method of technology transfer was mainly achieved with international joint ventures (hereafter IJV) linked with technology transferors from developed countries. As it is necessary to grasp the determinants of the technology transfer and their importance to promote the transfers through IJVs, this relative importance analysis study was conducted by using the method of quantifying experts' opinions (AHP) on the determinants of the technology transfer of both parties. As a result of the analysis, in the Hierarchy1(PEST factors), the technology transferees focus on economic factors such as 'profitability of technology transfer' and 'cost efficiency', while technology transferors considered technical factors such as 'operational excellence (abilities to continuously improve technology process)'. In addition, transferors and transferees have different priorities for technology transfer determinants in all areas of Hierarchy 2 (sub-determinants). This suggests that Korean government or enterprise should shift the policy direction toward 'technology-oriented' when they promote advanced-technology transfer through IJVs.

• Journal of Korea Technology Innovation Society
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• v.20 no.3
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• pp.519-545
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• 2017

This study analyzed the factors influencing the technology transfer of Government-Funded Research Institutes from the perspective of resource-based view. In particular, we analyzed the effects of research resources, research capacity, and research results diffusion variables on technology transfer performance. The research resource variables affect the primary output of R&D (patents, research papers) but direct effect on the technology transfer performance was very weak. Among the research competency variables, patent-related variables such as patent registration, patent holdings have a significant effect on the technology transfer performance. However, the research papers have a negative effect on the technology transfer performance. The research results diffusion variables such as TLO organization and TLO budget may partly have a positive impact on technology transfer, but the statistical significance is not clear.

• Journal of Embryo Transfer
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• v.13 no.1
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• pp.61-67
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• 1998

This study was carried out to establish an effective system for embryo transfer techniques by analyzing several factors affecting in-vivo embryo transfer in Korean cattle. Embryos produced in-vivo were transferred into a total of 301 recipients The results obtained in studies on the factors affacting pregnancy rate after embryo transfer by condition of recipients were as follows ; 1. The pregnancy rate by age and parity of recipients showed high in 5~8 and over 12 years old(72.7~73.9%), and 3rd~4th parity(82.1%) for fresh embryos(P<0.05). The pregnancy rate did not differ by age and parity of recipients in frozen embryos. The pregnancy rate of frozen embryos tended to be similar to that of fresh embryos(38.5% and 25.0~36.7%). 2. The number of observation for normal estrus cycles of recipients did not differ In pregnancy rate between one and 2 times in fresh embryos(64.9%, 69.8%). The pregnancy rate by transferred frozen embryos showed significantly higher after 2 times of observation(P<0.05, 16.3%, 37.5%). The pregnancy rate by days open did not differ between fresh and frozen embryos. But the pregnancy rate was slightly higher in 12 months and 6 months of days open for fresh and frozen embryos, respectively(70.1~71.1% and 24.5%, respectively). 3. The pregnancy rate of transferred fresh and frozen embryos into right and left side of uterine horn did not differ(62.1% : 65.9% 25.0% : 24.3%, respectively). The pregnancy rate by the grade of CL was not different in fresh embryos, but the pregnancy rate was significantly higher in the grade A than B for frozen embryos(P<0.01, 43.2%, 16.2%).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.3
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• pp.231-239
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• 2002

Experiments on the single phase cooling heat transfer and pressure drop with microfin tubes were performed using water as a test fluid. Experimental data were obtained in the range of Reynolds number 3000 ~40000 and Prandtl number 4-6. The data of microfin tubes presented the characteristics of rough surface tube in pressure drop and heat transfer Experimental data were compared with the heat transfer and friction factor correlations of smooth tubes. Heat transfer enhancements of microfin tubes were lower than pressure drop penalty factors. The helix angle is more significant parameter in both of the pressure drop and heat transfer than the relative roughness. The correlations of Nusselt number and friction factor were suggested for the tested microfin tubes. Maximum deviations between correlations and experimental data were within $\pm15$% for Nusselt number and $\pm10$% for friction factor.