• 한국광학회:학술대회논문집
• /
• 한국광학회 2001년도 제12회 정기총회 및 01년도 동계학술발표회
• /
• pp.4-5
• /
• 2001

Advent of lasers offering high intensity beam has opened the glass to the nonlinear optic (NLO). The high electric field associated with such laser beams can be so large that high order components of the glass polarization can be measured. Such development is of scientific and technological interests in particular in systems involving an intensity-dependent refractive index and/or ultra-fast response (＜10$\^$-12/s). From a scientific viewpoint the NLO response intensity must be understood as a function of the glass composition. On the other hand, large family of applications are presently under investigation in various fields of optical materials or systems e.g. laser glasses for fusion energy, soliton propagation for ultra-long distances, ultra-fast-switching, optical storage etc....(omitted)

• Journal of Electrical Engineering and Technology
• /
• 제13권4호
• /
• pp.1549-1557
• /
• 2018

Optimizing the design of large-scale electric machines based on nonlinear finite element analysis (FEA) requires longer computation time than other applications of FEA, mainly due to the huge size of the machines. This paper addresses a new region decision method (RDM) with mesh adaptive direct search (MADS) for the optimal design of wind generators in order to reduce the computation time. The validity of the proposed algorithm is evaluated using Rastrigin and Goldstein-Price benchmark function. Moreover, the algorithm is employed for the optimal design of a 5.6MW interior permanent magnet synchronous generator to minimize the torque ripple. Additionally, mechanical stress analysis as well as electromagnetic field analysis have been implemented to prevent breakdown caused by large centrifugal forces of the modified design.

• 전기학회논문지
• /
• 제68권1호
• /
• pp.44-51
• /
• 2019

Tunnel Boring Machine's Technology has depends mostly on imports, currently domestic technology development was proceeding. There are many technologies in this field, above all, the large-capacity motor drive technology required for excavation is one of the core technologies. In particular, when several large motors are simultaneously starting, there are many problems due to a large starting current at that time, and it is difficult to design and operate a power receiving facility. In this paper, A method of reducing the starting current by using the regenerative power generated by the deceleration of the motor has been studied. To verify this proposal, we designed the induction motor controller using CAE based power simulation tool and verified the results of the proposed method by applying the reduced model. As a result, it is possible to reduce the maximum starting current and shorten the start-up time. Moreover, even if several motors are connected to one bank, it is proved that the method can be efficiently operated by using the sequential braking / starting sequence. In the case of a power system in which a large capacity electric motor such as a tunnel excavation system is driven, the results of this study are expected to be a stable and effective method for solving the start-up current problem and designing the power receiving facility.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.1885-1891
• /
• 2010

Recently metropolitan local governments is actively introducing urban railway's expand and light rail transit as a means of new transport system. DC electricity feeder system operating in the domestic urban railway is typically a feedback circuit consisted of the contact wire and electric railway vehicle via rail. But stray current is to be defined as a current flowing on a structure that is not part of the intended electrical circuit with respect to a given structure. Stray current is generally results from the leakage of return currents from large DC traction systems that are grounded or have a bad earth-insulated return path. At the place where the current leaves the rail and metallic structures, electrolytic corrosion may take place. This paper presents comparison analysis of field test methods based on criteria of electrolytic corrosion protection of buried metallic structures adjacent to DC traction systems.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
• /
• pp.111-114
• /
• 2003

Compared to a conventional atomic layer deposition (ALD) grown Al203 film, Plasma enhanced ALD (PEALD) grown AION film was revealed to possess a large breakdown field, which is necessary for stable operation of thin film electroluminescent (TFEL) device. Also, AION is more stable than Al203 films grown by PEALD or by ALD after post-annealing process, which is inevitably required to improve luminance property of phosphor. Furthermore, AION films were applied to insulators of ZnS:Tb TFEL device. Resultant1y, they show better stability than ALD grown insulators under high electric field.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제5권5호
• /
• pp.332-339
• /
• 2000

Experimental and theoretical works were performed for the separation of large polyelectrolytes such as DNA in the column packed with gel particles under an electric field. This paper shows how intraparticle convection effects the separation of DNAs in the column because DNAs quickly oriented through the pores in the field direction. Dimensionless transient mass balance equations were derived considering diffusion and electrophoretic convection. The separation criteria is theoretically studied using two different Peclet numbers in the fluid and solid phases and these criteria were verified uing two different DNAs by electrophoretic mobilities measured experimentally, showing how the separation position of DNAs varies in the column according to values of Pe(sub)f/Pe(sub)g of individual DNA. Governing equations are simultaneously solved by operator theoretic and characteristic methods to yield the column response.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 춘계학술대회 논문집
• /
• pp.15-18
• /
• 2005

As a display becomes large recently, Acquisition of high luminance and Luminance uniformity is becoming difficult in the existing CCFL or EEFL backlight system. So, study for a performance enhancement has enforced. but lamp development of flat type is asked for high luminance and a luminance uniformity security in of LCD and area anger trend ultimately. In this paper, we changed a tip shape of an electrode for production by the most suitable LCD backlight surface light source, and confirmed discharge characteristic along discharge gas pressure and voltage, and confirmed electric field distribution and discharge energy characteristic through a Maxwell 2D simulation. Therefore the discharge firing voltage characteristic showed a low characteristic than a rectangular type and round type in case of electrode which used tip of a triangle type, and displayed a discharge electric current as a same voltage was low.

• 전력전자학회논문지
• /
• 제21권2호
• /
• pp.111-116
• /
• 2016

This paper proposes a high-frequency (MHz) LLC resonant converter for a capacitor coupling wireless power transfer (CCWPT). The CCWPT uses electric field in the coupling capacitor between the transmitter and receiver electrodes with a dielectric layer. Given that capacitance is very small and the impedance is large, transferring power with a simple series resonance is difficult. Therefore, the high frequency (MHz) and high Q factor LLC converter is proposed to reduce the impedance of the coupling capacitance and to obtain a high output voltage. This paper deals with the operation analysis of the proposed LLC converter and a theoretical capacitance estimation. The operation and features of the proposed CCWPT LLC converter is verified with a 4.2 W prototype for charging mobile devices.

• 한국콘텐츠학회논문지
• /
• 제14권9호
• /
• pp.582-588
• /
• 2014

본 연구는 국가간 공동연구 네트워크가 기술 지식의 확산에 어떠한 영향을 미치는 가와 네트워크 상에서 중심성이 높은 국가가 새로운 기술을 얼마나 받아들이는지 분석하고 그 의미를 찾는 것을 목적으로 한다. 이를 위해 이차전지 분야와 전기 자동차 분야 논문 정보를 이용하여 연도별 국가간 공동연구 네트워크 밀도와 참여국가 수를 측정하고 변수간의 회귀분석을 수행하였다. 분석결과, 이차전지 분야 공동연구 네트워크 밀도가 증가할수록 참여국가 수는 선형관계로 증가하는 것으로 나타났다. 또한 공동연구 네트워크 상에서 연결정도 중심성이 높은 국가들이 중대형 이차전지 분야 개발을 주도하고 있는 것으로 나타났다. 반면에 전기 자동차 분야의 경우, 네트워크 밀도값은 증가 추세가 나타나지 않지만, 참여국가 수는 증가하고 있는 것으로 나타났다. 이는 기술 확산을 촉진하는데 있어서, 국가간 공동연구가 중요한 역할을 하지만 필요충분 조건은 아닌 것으로 분석되었다. 이러한 결과는 기술 성장에 있어서 반드시 필요한 기술 확산을 촉진하는 요인을 통계적으로 검증하였다는 점에서 의의가 있으나, 네트워크 상에서 중심적 역할에 대한 지표를 연결정도 중심성 만으로 측정하였다는 점과 네트워크 밀도가 행위자간 상호작용에 있어서 반드시 두 행위자간 관계만을 측정한다는 점에서 연구의 한계가 존재한다. 따라서 향후 다수의 연구자간 상호작용을 측정할 수 있는 방안에 대한 연구가 필요하다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
• /
• pp.31-34
• /
• 2006

The characteristic of carbon nano fiber (CNF) as electron emitters was described. Carbon nano fiber (CNF) of herringbone was prepared by thermal chemical vapor deposition(CVD), mixed with binders and conductive materials, and then were formed by screen-printing process. In order to increase effectively field emissions, the surface treatment of rubbing & peel-off was applied to the printed CNF emitters on cathode electrode. The measurements of field emission properties were carried out by using a diode structure inline vacuum chamber. CNF of herringbone type showed good emission properties that a turn on field was as low as $2.5V/{\mu}m$ and current density was as large as $0.15mA/cm^2$ of $4.5V/{\mu}m$ with electric field. After the vacuum packaged panel of 5-inch in diagonal, the measured white brightness was as high as $7000cd/m^2$ at 1900V of anode and 700V of gate voltage.