• Journal of Power Electronics
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• 제13권5호
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• pp.798-805
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• 2013

This paper presents the control and implementation of the dual-stator-winding induction generator for variable frequency AC (VFAC) generating system. This generator has two sets of stator windings embedded into the stator slots. The power winding produces the VFAC power to feed the loads, and the control winding is connected to the static excitation controller to control the generator for output voltage regulation with speed and load variations. On the basis of the idea of power balance, an instantaneous slip frequency control (ISFC) strategy using the information of both the output voltage and the output power is used in this system. A series of experiments is carried out on a 15 kW prototype for verification. Results show that the system has good static and dynamic performance in a wide speed range, which demonstrates that the ISFC strategy is suitable for this system.

• 한국생산제조학회지
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• 제24권1호
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• pp.81-86
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• 2015

This paper presents a disposable passive suction pump that uses the restoring force of an elastomeric chamber for liquid transportation in a microfluidic system. The proposed suction pump can be operated by finger pressure without any peripheral equipment. To adjust the generated suction pressure, five different displacements of the suction chamber ceiling, two different chamber shapes, and five different elastic moduli of the elastomer were considered. For a cylindrical chamber with a 5 mm height and 5 mm radius, the generated suction pressure and flow rate increased almost linearly up to about 31 kPa and $160.8{\mu}L/min$, respectively, depending on the chamber deformation. A maximum suction pressure of $42.9{\pm}0.7kPa$ was obtained for a hemispherical chamber with a 2.1 mm height and 5 mm radius.

• 전기학회논문지
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• 제66권12호
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• pp.1830-1835
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• 2017

8200 Series Electric Locomotives are mostly imported from overseas due to aging and uncertainty of source technology, and it's the maintenance cost is increasing. We are analyzed life cycle costs based on international standards such as IEC 60300-3-3 and IEC62278. The main conversion system of the 8200 series electric locomotive is closely related to vehicle operation and is one of the subsystems requiring frequent maintenance. In this paper, the life cycle cost of the main conversion unit in 8200 series electric locomotive is analyzed based on the maintenance manual. As a result of analysis, maintenance cost of GTO module and control device is relatively high, and it is confirmed that the cost increases according to the useful life.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.112-117
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• 2002

This paper will present the basic concept and technical trends of the 42V system for the future vehicles structure that is in the process of research and development by the world-wide vehicle manufacturers and the suppliers. The power conversion equipment on the vehicles and an ISG(Integrated Starter Generator) for 42V are introduced. The fundamental research related to the advanced automaker's technical trends and investigations are performed.

• 전기학회논문지
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• 제56권6호
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• pp.1105-1110
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• 2007

This paper describes an equivalent circuit modeling of 4-port connector system. A coupled transmission line was designed and fabricated, mimicking a 4-port connector system, and then S-parameters were measured using 4 port VNA (Vector Network Analyzer). The S-parameters from measurement and from Full-wave simulator coincided quite nice. By using these S parameters, an equivalent circuit parameters for a 4-port system was obtained. The time domain response from the equivalent circuit model matched to the signals, which was measured using TDR(Time Domain Reflectometry) meter. We were also convinced that there should be enough bandwidth to get a meaningful time domain result from Fourier inverse transformation of the S parameters. In addition, we applied the conversion algorithm to the 4-port connector system, which calculates the S-parameters of a 4 port system using the data from a 2-port VNA with the other ports open. Comparison of the two data, one from measurement and the other one from the conversion algorithm, was made in this manuscript.

• 전기학회논문지
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• 제67권12호
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• pp.1717-1722
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• 2018

Parts and units of 8200 series electric locomotive are aging, but and source technology is not secured. As a results, maintenance costs are increasing steadily due to using expensive substitute parts. Therefore, various studies have been conducted to reduce maintenance costs. In this paper, the life cycle cost(LCC) of the developed and conventional products were compared and analyzed about main conversion system in 8200 Series electric locomotive. As a result of analysis, the material cost was the highest in the conventional product among the various item costs. On the other hand, it is confirmed that preventive cost was the highest among the costs about the developed product.

• 한국통신학회논문지
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• 제1권1호
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• pp.23-31
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• 1976

VHF 및 UHF 챠넬의 TV 信號는 映像 및 音聲을 포함한 6MHz의 대역폭으로 챠넬變換 된후 直線增幅器를 통해 재 送信될 때 搬送波付近의 兩側波帶傳送領域에서 出力振幅周波數特性에 不自然스러운 變化가 생겨 화질에 影響을 주는수가 있다. 이러한 現像은 發振器로 부터의 不要信號로 因한 不要下側帶波의 發生등 問題가 되는 要因인 트랜지스터 直線增幅器의 非直線性, MIXER 회로에서의 상호변조 歪 AM-PM 變換 및 envelope delay 特性 등을 고려하여 出力特性을 구한 결과 主原因은 非直線性에 의한 것이였으며 實驗結果로서는 非直線性의 主因으로 Bias 조건의 불합리 및 發振器로 부터의 不要周波數의 發生이 가장 큰 原因으로 나타났다. 특히 인접信號에 對한 相互變調歪 및 不要信號發生은 Up conversion의 경우가 Down Conversion의 경우보다 현저히 감소됨을 확인하였고 發振器로부터의 spurious가 system에 영향을 주지 않는 方案을 모색하였다.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.1-8
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• 1999

Most carbohydrates exist in nature in an insoluble state, which reduces their susceptibility towards various carbohydrases. Accordingly, they require intensive pretreatment for structural modification to enhance an enzyme reaction. The direct conversion of insoluble carbohydrates has distinct advantages for special types of reaction, especially exo-type carbohydrase; however, its application is limited due to structural constraints. This paper introduces two novel heterogeneous enzyme reaction systems for direct conversion of insoluble carbohydrates; one is an attrition coupled enzyme reaction system containing attrition-milling media for enhancing the enzyme reaction, and the other is a heterogeneous enzyme reaction system using extruded starch as an insoluble substrate. The direct conversion of typically insoluble carbohydrates, including cellulose, starch, and chitin with their corresponding carbohydrases, including cellulase, amylase, chitinase, and cyclodextrin glucanotransferase, was carried out using two proposed enzyme reaction systems. The conceptual features of the systems, their reaction characteristics and mechanism, and the industrial applications of the various carbohydrates are analyzed in this review.

• 대한기계학회논문집B
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• 제33권12호
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• pp.952-960
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• 2009

Selective Catalytic Reduction (SCR) system is a high-effective NOx reduction technology in diesel engines. As the emission standard of diesel engines is more stringent, vehicle manufactures makes efforts on emission technologies. This paper discusses the performance of Urea-SCR system according to the engine operating conditions in a passenger diesel engine. Engine test results in this paper show that it is important to consider the catalyst temperature and space velocity to obtain high NOx conversion efficiency. In condition of high catalyst temperature, over 90% NOx conversion efficiency is indicated. However, when catalyst temperature is low, NOx conversion efficiency was decreased. Also, it was shown that space velocity mainly effects on the DeNOx performance under 220 degree celsius of SCR catalyst temperature. As the urea injection pressure was decreased, NOx conversion efficiency was declined. It is concerned about urea droplet atomization. This work shown in this paper can lead to improved overall NOx conversion efficiency.

• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.65-69
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• 2019

The cure properties of ethoxysilyl diglycidyl isocyanurate(Ethoxysilyl-DGIC) and ethylsilyl diglycidyl isocyanurate (Ethylsilyl-DGIC) epoxy resin systems with a phenol novolac hardener were investigated for anticipating fan out-wafer level package(FO-WLP) applications, comparing with ethoxysilyl diglycidyl ether of bisphenol-A(Ethoxysilyl-DGEBA) epoxy resin systems. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The isocyanurate type epoxy resin systems represented the higher cure conversion rates comparing with bisphenol-A type epoxy resin systems. The Ethoxysilyl-DGIC epoxy resin system showed the highest cure conversion rates than Ethylsilyl-DGIC and Ethoxysilyl-DGEBA epoxy resin systems. It can be figured out by kinetic parameter analysis that the highest conversion rates of Ethoxysilyl-DGIC epoxy resin system are caused by higher collision frequency factor. However, the cure conversion rate increases of the Ethylsilyl-DGEBA comparing with Ethoxysilyl-DGEBA are due to the lower activation energy of Ethylsilyl-DGIC. These higher cure conversion rates in the isocyanurate type epoxy resin systems could be explained by the improvements of reaction molecule movements according to the compact structure of isocyanurate epoxy resin.