• 한국주조공학회지
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• 제13권2호
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• pp.168-174
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• 1993

It has been known that the grain refinement of Cu base alloys greatly improved mechanical properties, castability, workability and hot shortness resistance etc. In this study CuZr50, CuP7, CuFe7, CuMg10 binary alloys were added as grain refiners in CuZn36 alloy. The alloys melted in vacuum and controlled in mixed gas conditions and casted at $1050^{\circ}C$. Zr-P-X compound has significantly grain refined but oxygen has been found detrimental to grain refinement. In the case of Zr /B ratio below 4, B acted as grain growth element in this alloy.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.560-564
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• 2001

본 연구에서는 3상 능동 직렬형 전압 보상기의 제어 알고리즘으로 공간 벡터 검출법(3-D SV)을 제안하고 있다. 제안된 3차원 공간 벡터법은 종전의 순시전력이론에 의한 방법에 비해 보상 기준치 연산과정을 간략화 할 수 있고 좌표변환이 필요치 않다. 제안된 알고리즘은 전원전압의 순간적인 sag가 발생되더라도 비선형 부하에 인가되는 전압은 일정한 정현파로 제어 가능하며 동시에 전원전류의 고조파와 기본파 무효전류도 보상 가능하다. 정상상태와 과도상태에서 전력전자전용 시뮬레이터인 PSIM에 의해 제안된 이론의 타당성을 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.152-157
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• 2002

This paper describes the implementation of 3-phase 3-wire active power filter system with a instantaneous PSD for distorted and unbalanced power conditions. The positive sequence voltage of the distorted and the unbalanced power system Is calculated by the instantaneous PSD, and phase transformation matrix of the instantaneous power theory is achieved with detected positive sequence voltage. Finally, the proposed method is experimented and tested under unbalanced nonlinear load as well as unbalanced/distorted condition in power system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.25-28
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• 2002

In this paper, 2 phase modulated SRPP-PWM(Separately Random Pulse Position PWM) is proposed. This PWM technique is based on the 2 phase modulated SVPWM(Space Vector Pulse Width Modulation). In according to the theory of SVPWM, 2 phase modulated SVPWM uses two pulses, not three pulses as in 3 phase modulated SVPWM. In the proposed SRPP-PWM scheme, each of two phase pulses is located randomly in each switching interval. The experimental results show that the voltage and switching noise harmonics are spread to a wide band area. Also, the performance of the proposed 2 phase modulated SRPP-PWM and the conventional SVPWM are compared to each other In result, the speed response is nearly similar to each other from the viewpoint of the v/f constant control.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.55-58
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• 2008

This article describes power supply infrastructure construction methods which are considered from U-City infrastructure. For the eisting city and town, it is one the issue to find an economic method to construct outside infrastructure including ubiquitous service device. Because the economic construction method could minimize the construction budget which cost big portion of U-City. And the power supply infrastructure is the fundamental layer to keep network and service layer stable. This paper suggests several ways to construct methods with keeping pre-constructed underground power cable by attaching inepensive power nodal controller working in zigbee network and introduces how to monitor and mana ge the status of power supply to network and service device.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.4-6
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• 2008

본 논문에서는 새로운 비대칭 PWM 제어 방식의 양방향 하프브리지 컨버터를 제안한다. 제안한 컨버터는 구조가 간단하고 넓은 듀티 범위를 가지므로 연료전지와 같은 넓은 전압변동을 가지는 응용에 적합하다. 제안한 비대칭 PWM 방식은 기존의 위상각제어 방식에 비해 스위치 및 변압기의 동작전류를 큰 폭으로 낮추었고 ZVZCS와 동기정류 방식을 적용하여 높은 효율과 전력밀도를 가질 수 있다. 기존 컨버터와의 비교 분석을 수행하였으며 실험을 통해 본 방식의 타당성을 검증하였다.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2005년도 추계학술발표대회 논문집
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• pp.233-234
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• 2005

The design in this study is making a plan for the exterior color design for the factory of the H. company. The concept of this design is an integrated color program considering the physical characteristics of the buildings and the functional features of the factories. And this program is based on the aesthetic characteristics forming the men-friendly, professional environment and the environment-friendly, factory image. The scope of this design was limited to the exterior color for 1 office building and 3 factory buildings, including 7 attached facilities. All the 6 colors were selected, and the blue, the company logo color, is the main color.

• 생약학회지
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• 제24권4호
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• pp.313-318
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• 1993

The methanol extract of Taraxaci Herba was found to have inhibitory effect on the gastric lesion induced by HCl-ethanol. The systematic fractionation of the methanol extract resulted in positive action with water fraction in the gastric lesion. It also showed significant inhibition of gastric lesion induced by HCl-aspirin and absolute ethanol, but did not prevent indomethacin induced gastric lesion. This fraction did not affect basal gastric acid secretion but showed a decrease of pepsin activity in pylorus-ligated rats.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.13-16
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• 2006

Electro-electrodialysis (EED) experiments were carried out for the HI concentration from HIx $(HI-H_2O-I_2)$ solution to improve the Hl decomposition reaction in the thermochemical water-splitting is (iodine-Sulfur) process. EED cell is composed of the collector electrode and electrolyte. Nafion 117 which was cation exchange membrane used as an electrolyte, and the activated carbon cloth used as an electrode. The HI concentration experiment was carried out using the HIx solution and molar ratio of the $I_2$ were varied from 1 to 3 mole. The cell voltages were decreased as temperature increase. And, membrane properties such as transport number of proton and electro-osmosis coefficient were decreased as temperature increase

• 한국문헌정보학회지
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• 제31권3호
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• pp.23-51
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• 1997

필자들은 왜 지금 학교도서관을 이야기해야 하며, 학교도서관을 이야기하는 주체는 누구인지, 그리고 어떻게 학교도서관을 이야기해야 하는지 설명한다. 필자들의 강조 점은 우리 현장에서 건져 올리는 논제, 우리 현장의 현 단계가 요구하는 연구방법, 그리고 논제와 연구방법에 걸맞는 유연한 글쓰기로 모아진다.