• Membrane Journal
• /
• v.31 no.6
• /
• pp.456-470
• /
• 2021

In this study, polyetherimide-based hollow fiber membranes were manufactured using the NIPS (nonsolvent induced phase separation) method. THF, Ethanol, and LiNO₃ were used as additives to control the morphology of the PEI-hollow fiber membranes. Furthermore, for the development of a high hydrogen separation membrane, the spinning conditions were optimized through the characterization of SEM and gas permeance. As a result, as the content of THF increased, the hydrogen/carbon dioxide selectivity increased. However, the permeance decreased due to the trade-off relationship. When ethanol was added, a finger-like structure was shown, and when LiNO₃ was added, a sponge structure was shown. In particular, in the case of a hollow fiber membrane with an optimized PDMS coating layer, the permeance was 40 GPU and the hydrogen/carbon dioxide selectivity was 5.6.

• Rubber Technology
• /
• v.22 no.2
• /
• pp.119-149
• /
• 2021

Domestic materials & components industry is making a shift from quantitative growth to qualitative growth, while the paradigm of a future society is changing rapidly to energy, mobility, smartification and etc. The main features of materials & components industry are analyzed broadly based on three aspects that are: ① industry Status, ② the value chain structure, ③ the competitiveness. With regard to the national aspect, it is shown that the number of an export and a trade surplus increased consistently after the government advanced the policy on materials & components and Korea's trade deficit with Japan has been decreased. Moreover, the state's export ranking increased from tenth place in 2001 into sixth place in 2017, dedicating to the growth of a national economy. The analysis of the chain value indicates that specifications of an end product are set when the materials & components are combined with manpower, infrastructure and technologies. In terms of the competitiveness, it requires a long time and high costs to develop technologies on materials and it is important for components to have a process innovation and credibility wired. Following the industry structure with priority given on materials, Jeonnam Province accounts for 14.8% of national material production. As a result of analyzing Jeonnam's export competitiveness, it is measured that a serious polarization exists, revealing there are 6 major technology industries by 11 categories for materials & components, Jeonnam has presented 6 major materials & components considering the key industry and the new industry in future to remedy the mentioned problem so far, and plans to knock on the industry development through 10 different strategies.

• Membrane Journal
• /
• v.32 no.5
• /
• pp.336-347
• /
• 2022

Reverse electrodialysis (RED) is one of the promising eco-friendly renewable energy technologies which can generate electricity from the concentration difference between seawater and freshwater by using ion-exchange membranes as a diaphragm. The ion-exchange membrane is a key component that determines the performance of RED, and must satisfy requirements such as low electrical resistance, high permselectivity, excellent durability, and low manufacturing cost. In this study, pore-filled anion-exchange membranes were fabricated using porous polymer substrates having various thicknesses and porosity, and the effects of ion-exchange polymer composition and membrane thickness on the power generation performance of RED were investigated. When the electrical resistance of the ion-exchange membrane is sufficiently low, it can be confirmed that the RED power generation performance is mainly influenced by the apparent permselectivity of the membrane. In addition, it was confirmed that the apparent permselectivity of the membranes can be improved through IEC, crosslinking degree, membrane thickness, surface modification, etc., and the optimum condition must be found in consideration of the trade-off relationship with electrical resistance.

• Transactions of the KSME C: Technology and Education
• /
• v.1 no.1
• /
• pp.107-113
• /
• 2013

This paper presents the process of turbine development for Organic Rankine Cycle(ORC) system. Development of turbine for ORC system is hot issue in the electric generation market due to the characteristic of organic refrigerant which the evaporate temperature is lower than general refrigerant. Recently, the industry have an interest about ORC turbine development in Korea, and they presented numerous research results. In developing the turbine, several processes can be considered. However, there was few document about ORC turbine development because of the trade secret. This paper can be used as a reference in developing ORC turbine.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.49 no.10
• /
• pp.34-42
• /
• 2012

This paper analyses the energy saving basic power models in core IP networks, and proposes the adaptive buffer and burst scheme which is a possible energy saving method, and its implementation algorithm in core IP networks. Especially this paper describes the adaptive buffer and burst scheme dynamically varying the buffering interval B according to the input traffic volume of ingress router, and explains the operation principle of proposed scheme. This method is to adjust the buffering interval B according to input traffic volume of ingress router, that is increasing the interval B when input traffic volume is low, and decreasing the interval B when input traffic volume is high between some given interval regions. This method can gets the high energy saving effect as decreasing the transition number of idle/active in networks when input traffic volume is low, and decreasing the transition number of idle/active by the continuous of burst packets in transit router when input traffic volume is high. This paper shows the increasing of asleep rate for the energy saving of core IP networks and confirms the energy saving of core IP networks by the computer simulation. We confirmed that proposed method can be save the energy of IP networks by properly trade off network performances.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.1
• /
• pp.1-6
• /
• 2002

Cogging torque is often a principal source of vibration and acoustic noise in high precision spindle motor applications. In this paper, cogging torque is analytically calculated using energy method to show that Fourier spectra of airgap permeance function and airgap MMF function are the most important design parameters to control cogging torque. To control these functions, stator pole shoe pairing and magnet arc design are proposed to minimize cogging torque. As for optimization technique, genetic algorithm is applied to handle trade-off effects of design parameters. Results show that the proposed method can reduce the cogging torque effectively.

• Asian Journal of Innovation and Policy
• /
• v.8 no.3
• /
• pp.343-361
• /
• 2019

The Practical Guide of Technology Valuation (the guide) by the Ministry of Industry, Trade and Energy is dominant in technology valuation in the public sector in Korea. The guide was released in 2011 and revised every three years. However, there are several guidelines or manuals for technology valuation issued by other agencies under different ministries. This paper compares the several guidelines for technology valuation and figures out the similarity and differences, from the view of the US and international standards of valuation. The first aspect found is that the guide is evolving toward the basic principles of valuation. Second, all the guidelines should comply with the guide but have sector-specific characteristics in methods, variables and data. Third, although the guide recommends only two valuation methods, some guidelines introduce various other methods. Fourth, the methods are still too complex and having unnecessary ingredients. Finally, this paper suggests further development of the guide and other guidelines.

• Korean Journal of Organic Agriculture
• /
• v.12 no.1
• /
• pp.67-80
• /
• 2004

Farm economy is getting worse because of the free trade trends in agriculture sector and unreasonable application of market economy principles to agricultural products. And The worldwide issues of environmental pollution as well as want of food, water and energy make human future be anxious. In addition, consumers raise questions in argument about safety of foods produced by traditional farming or imported. So I propose the urban-rural living community movement(URLCM) as an alternative plan for sustainable domestic agriculture. URLCM based on environmentally friendly agriculture and community consciousness will be able to solve many of present issues on agriculture and rural society through incessant interchanges between urban and rural community. This URLCM has to be basically founded on principles of symbiosis-coexistence and life circulation. So those that have to be driven forward arc organizing producers and consumer cooperatives, making environmentally friendly rural region and products, combining with consumer cooperatives, training the participants and so forth.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.05a
• /
• pp.378-384
• /
• 2005

This paper presents the prospects of today's situation of Korea Electric Power Industry and future's development direction at the sudden chin international environment Several paradigm,-Deregulated electric market Energy shortage, Green house effect due to $CO_2$, TBT(Technical Barrier to Trade), Digital society-will facilitate the glove to develope new technology based Power Industry. With respect to this change, Korea Power Industry needs to find new technology solutions for the smarter operation, higher efficiency and lower carbon consuming power system based on mid-long term plan.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.331-332
• /
• 2006

This paper proposes the fuel cell power plants as alternative energy sources for distributed generation in Jeju Island, Korea. This will help to increase the fuel efficiency, at least double the current thermal power plants, decrease environmental pollution, virtually to none, increase the reliability of power supply, reducing the dependency of the HVDC link, and provide quality power to the growing infrastructure in meeting the requirements for the free-trade international island.