• Journal of ILASS-Korea
• /
• v.10 no.4
• /
• pp.26-31
• /
• 2005

Today, the research to examine a fact that interaction between the air and the fluid free surface affects the steady state flow and air. We proved the interaction between vortex pairs and free surface on each condition that is created by the end of delta wings. Another purpose of this study is to investigate the effect of surface active material which call change the surface tension and we must consider when we refer to turbulent flow on surface tension. Therefore, this research examined the growth process of vortex pairs on condition of clean, contaminated free surface and wall after we made vortex pairs through counter rotating flaps. The results of this study suggest that vortex pairs in clean free surface rise safely but the vortex pairs in contaminated free surface and rigid, no slip is made secondary vortex or rebounding. However the secondary vortex in rigid, no slip is stronger than before. and we can find the vortex shape which roll up more completely. However, these will disappear by the effect of wall.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2002.08a
• /
• pp.86-98
• /
• 2002

When the quality and cooking characteristics of wash free rice was compared with those of control milled rice during storage, smaller quality change during storage and more easy to cook was found in wash free rice than control. The wash free rice equipment manufactured in foreign country was carefully investigated and commercial wash free rice equipment with 1metric ton per hour capacity was made considering the characteristics of domestic rice cultivar. Modification of the equipment was made through the repeated field test, and the technique on wash free rice equipment was transferred to the RICETECH. These systems were manufactured in RICETECH will be exported to China next year.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.3
• /
• pp.357-362
• /
• 2016

The objective of this study is to investigate the perception and satisfaction of elementary and middle school students on free school food service. We surveyed education related to school food service, concerns about food ingredients, perceptions of free school food service and satisfaction for the quality of the school food service. The investigation is classified into two groups, schools that operate as a food service center or those that do not. Those who are provided food ingredients by school food service centers are educated about the agricultural products' country-of-origin and their environment-friendly food service. The more individuals are educated of the foods' county-of-origin and environment-friendly food service the more they will have a higher concern of the food materials and subsequently a higher satisfaction for the quality of school food service. School food service centers managed directly by the local government would probably receive higher satisfaction than those consigned to a private sector. The results of this study will be meaningful to establish policies on school food service and school food service centers.

• Transactions of the KSME C: Technology and Education
• /
• v.5 no.2
• /
• pp.81-87
• /
• 2017

315Fr compressor motor exceeds vibration specifications. To find the reason, first a modal impact test with free-free condition is done. Second a modal test with fixed condition is done. Thereafter the test results are compared with FEM simulation results. Using free-free condition modal impact test, FEM simulation conditions (boundary, mesh..) are modified. The motor has rolling motion around 120Hz. FEM simulation also shows same result. FEM simulation will be used to develop other series compressor motors. Using this, manufacturing test model and doing test will be useless.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2016.05a
• /
• pp.154-155
• /
• 2016

Although there is an increase in demand for free-form buildings, there are several problems such as increased cost and duration and decreased constructability arising from difficult member production and installation. To solve these problems, a technology to produce free-form panels using CNC machine was developed. According to the technology, the information on free-form buildings designed is delivered to the CNC machine, a form is shaped using the delivered information and free-form concrete panels are produced using the form. The limited construction site, duration and project cost as well as interferences with other work types should be considered upon in-situ production of free-form concrete panels. Thus, the purpose of this study is to conduct a base study on in-situ production layout of free-form concrete panels by system dynamics. With this study, we will discover the causal relationship of influence factors on in-situ production of free-form concrete panels, and improved productivity is expected through the production layout.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.96-97
• /
• 2012

In nitride and oxide film deposition, sputtered metals react with nitrogen or oxygen gas in a vacuum chamber to form metal nitride or oxide films on a substrate. The physical properties of sputtered films (metals, oxides, and nitrides) are strongly influenced by magnetron plasma density during the deposition process. Typical target power densities on the magnetron during the deposition process are ~ (5-30) W/cm2, which gives a relatively low plasma density. The main challenge in reactive sputtering is the ability to generate a stable, arc free discharge at high plasma densities. Arcs occur due to formation of an insulating layer on the target surface caused by the re-deposition effect. One current method of generating an arc free discharge is to use the commercially available Pinnacle Plus+ Pulsed DC plasma generator manufactured by Advanced Energy Inc. This plasma generator uses a positive voltage pulse between negative pulses to attract electrons and discharge the target surface, thus preventing arc formation. However, this method can only generate low density plasma and therefore cannot allow full control of film properties. Also, after long runs ~ (1-3) hours, depends on duty cycle the stability of the reactive process is reduced due to increased probability of arc formation. Between 1995 and 1999, a new way of magnetron sputtering called HIPIMS (highly ionized pulse impulse magnetron sputtering) was developed. The main idea of this approach is to apply short ${\sim}(50-100){\mu}s$ high power pulses with a target power densities during the pulse between ~ (1-3) kW/cm2. These high power pulses generate high-density magnetron plasma that can significantly improve and control film properties. From the beginning, HIPIMS method has been applied to reactive sputtering processes for deposition of conductive and nonconductive films. However, commercially available HIPIMS plasma generators have not been able to create a stable, arc-free discharge in most reactive magnetron sputtering processes. HIPIMS plasma generators have been successfully used in reactive sputtering of nitrides for hard coating applications and for Al2O3 films. But until now there has been no HIPIMS data presented on reactive sputtering in cluster tools for semiconductors and MEMs applications. In this presentation, a new method of generating an arc free discharge for reactive HIPIMS using the new Cyprium plasma generator from Zpulser LLC will be introduced. Data (or evidence) will be presented showing that arc formation in reactive HIPIMS can be controlled without applying a positive voltage pulse between high power pulses. Arc-free reactive HIPIMS processes for sputtering AlN, TiO2, TiN and Si3N4 on the Applied Materials ENDURA 200 mm cluster tool will be presented. A direct comparison of the properties of films sputtered with the Advanced Energy Pinnacle Plus + plasma generator and the Zpulser Cyprium plasma generator will be presented.

• Journal of Digital Convergence
• /
• v.20 no.5
• /
• pp.85-92
• /
• 2022

In recent years, the world's free trade system has been severely damaged by a series of protectionist measures in the United States and anti-globalization practices such as Brexit. Against this background, RCEP, the world's largest trade agreement, was officially signed on November 15, 2021. The RCEP provided a good working basis for the establishment of a Korea, China, and Japan free trade zone. First, this paper describes the current status of Korea-China-Japan trade cooperation and the current status of the trilateral telecommunication industry. Second, this paper simulates the changes in the overall economy of China, Japan, and Korea when tariffs are reduced to 0%, 5%, and 10%, respectively, after the establishment of a free trade zone using the 8th edition GTAP database. Then, using the simulated data changes and using the 2019 data as a benchmark, we calculated the changes in the RCA index for the three countries' telecommunications industries for the three tax rates. In the end, it is concluded that the economies of the three countries will grow to different levels in many ways when the Korea, China, and Japan free trade zone is established. Japan's telecommunications industry will not be significantly affected, Korea will grow significantly with higher tax rates and China will grow significantly with lower tax rates.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2000.04a
• /
• pp.6-7
• /
• 2000

Recently, free radicals such as active oxygen species, nitric oxide, etc are believed to be one of the key substances in physiological and pathological, toxicological phenomena, and oxidative damages, and all organism have defencing system against such as free radicals. Formation and extinction of free radicals may be regulated through bio-redox system, in which various enzymes and compounds should be involved in very complicated manner. Thus, direct and non-invasive measurement of in vivo free radical reactions with living animals must be essential to understand the role of free radicals in pathophysiological phenomena. Electron spin resonance spectroscopy (ESR) is very selective and sensitive technique to detect free radicals, but a conventional ESR spectrometer has large detect in application to living animals, since high frequent microwave is absorbed with water, resulting in generation of high fever in living body. In order to estimate in vivo free radical reactions in living whole animals, we develop in vivo ESR-CT technique using nitroxide radicals as spin probes. Nitroxide radicals and their reduced forms, hydroxylamines, are known to interact with various redox systems. We found that! ! the signal decay due to reduction of nitroxyl radicals is influenced by aging, inspired oxygen concentration, ischemia-referfusion injury, radiation, etc. In the present paper, I will introduce in vivo ESR technique and my laboratory recent results concerning non-invasive evaluation of free radical reactions in living mice.

• Journal of Korean Elementary Science Education
• /
• v.20 no.2
• /
• pp.271-280
• /
• 2001

The purpose of this study is to investigate how free inquiry activities affects the scientific process skills and scientific attitudes of 5th and 6th of elementary school students. For this study, 265 elementary students from 5th and 6th grade in Seoul were selected. In comparison group 130 students were implemented and to the experimental group 135 students who did not the free inquiry activities were implemented. The result of this study is as follows: First, curiosity was the most affective factor that motivate free inquiry activities and made them select their topics. Most of the students invested for the inquiry activity in less than 3 weeks. They had some help in every stages. Students became interested in free inquiry activities because they learned new facts and enjoyed doing experiments and they wanted to continue for the same reasons. Second, free inquiry activities had little effect on the basic science process skills of the experimental group, compared to the control group at the significant difference of p=0.05. Third, free inquiry activities had considerable effect on the integrative inquiry process skills of the experimental group, compared to the control group at the significant difference of p=0.05. Fourth, the result of the post-test of the experimental group showed that free inquiry activities had no effect on scientific attitudes at the significant difference of p=0.05. In conclusion, free inquiry activities will be much more effective in developing integrative inquiry process skills than in developing basic scientific process skills and scientific attitudes.

• Journal of Korean Port Research
• /
• v.2 no.1
• /
• pp.29-73
• /
• 1988

Since the middle of 1950's when sea transportation service by container ship was established, containerization has been rapidly spread over the world with realization of intermodalism, and becomes an index of economy growth of a country. Our country has established Pusan Container Terminal at Pusan harbour in 1978 in step with worldwide trend of containerization, and is constructing New Container Terminal at Pusan outharbour which will be completed in 1990. This paper aims to make a quantitative analysis of the Pusan Container Terminal system through the computer simulation, especially focusing on its subsystems such as ship stevedoring system, storage system and transfer system. First, the capacity of various subsystems are evaluated and it is checked whether the current operation is being performed effectively through the computer simulation. Secondly, the suggestion is presented to improve the operation by considering the throughput that Pusan Container Terminal will have to accept until 1990, when New Container Terminal will be completed. The results are as follows ; 1) As the inefficiency is due to the imbalance between various subsystems at Pusan Container Terminal on the basis of about 1.2 million TEU of container traffic, transfer equipment level must be up to 33% for transfer crane, and free period must be reduced into 4/5 days for export/import. 2) On the basis of about 1.4 million TEU of container traffic, transfer equipment level must be up to $12\%$ for gantry crane, $11\%$ for straddle carrier and $66\%$ for transfer crane, and free period must be reduced into 3/4 days for export/import. 3) On the basis of about 1.7 million TEU of container traffic, transfer equipment level must be up to $25\%$ for gantry crane, $28\%$ for straddle carrier and $100\%$ for transfer crane, and free period must be reduced into 3/4 days for export/import. 4) On the basis of about 2 million TEU of container traffic, transfer equipment level must be up to $25\%$ for gantry crane, $30\%$ for straddle carrier and $110\%$ for transfer crane, and free period must be reduced into 2/3 days for export/import, and it is necessary to enlarge storage yard.