• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.273-275
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• 2003

본 실험은 고출력 반도체 레이저의 p-side-down 마운팅용 솔더로서 AuSn 합금 솔더(80wt%:20wt%)의 적합성에 대해 연구하였다. $1{\mu}m$이하의 균일도로 폴리싱 된 Cu heat sink의 표면에 두께 $1{\mu}m$의 Ni로 코팅을 한다음, AuSn 다층박막은 e-beam 증착기로 AuSn 합금 솔더는 열증착기로 각각 증착하였다. 열처리는 산화 방지를 위해 $N_2$ 분위기에서 행하였으며, 동일한 압력으로 마운팅을 하였다. 표면의 거칠기와 형상은 AFM(Atomic Force Microscope)과 SEM(Scanning Electron Microscopy)으로 그리고 Au와 Sn의 성분비는 AES(Auger Electron Spectroscopy) 로 비교하였다. 또한 CW(연속발진)을 통한 L-I(Light-Current)측정을 통해 본딩상태를 비교하였다.

• 제어로봇시스템학회논문지
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• 제13권5호
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• pp.481-486
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• 2007

Wireless Sensor Network(WSNs) consists of small sensor nodes with sensing, computation, and wireless communication capabilities. The large number of sensor nodes in a WSN means that there will often be some nodes which give erroneous sensor data owing to several reasons such as power shortage and transmission error. Generally, these sensor data are gathered by a sink node to monitor and diagnose the current environment. Therefore, this can make it difficult to get an effective monitoring and diagnosis. In this paper, to overcome the aforementioned problems, intelligent sensor data validation method based on PCA(Principle Component Analysis) is utilized. Furthermore, a practical implementation using embedded system is given to show the feasibility of the proposed scheme.

• 설비공학논문집
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• 제16권1호
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• pp.62-69
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• 2004

Thermoelectric module is a device that can produce cooling in a direct manner using the electrical energy. The purpose of this study is to investigate the performance of thermoelectric module and cooling system equipped with the thermoelectric module. The performance of a thermoelectric module is estimated using two methods; theoretical analysis based on one-dimensional energy equations and experimental tests using heat source, heat sink and brass conduction extenders. For the thermoelectric cooling system, the temperatures in the chamber are recorded and then compared with those of lumped system analysis. The results show that the cooling capacity and COP of the thermoelectric module increases as the temperature difference between hot and cold surface decreases, and there is particular current at which cooling capacity reaches its maximum value. The experimental results for the thermoelectric cooling system are similar to those of lumped system analysis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.221-225
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• 2001

In the paper, we report on the DC and Thermal effect of the GaN based HFET. A physics-based a model was applied and found to be useful for predicting the DC performance and Thermal effect of the GaN based HFET by Various substrate. The performance of device on the sapphire substrates is found to be significantly improve compared with that of a device with an sapphire substrate. The peak drain current of the device achieved at HFET on the SiC substrate

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.502-505
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• 1988

This paper is to demonstrate the effectiveness of one point grounding in support of ESS protection. One point grounding provides for the dispatching of excess energy for protection of switching equipment and personnel from lightning discharge hazards and for a natural sink for noise from atmospheric lightning and power transients. In most ESS installations there are a number of different items that must be maintained at a common ground potential for safety, fault protection or noise reduction. The items typically consist of power systems, heating and ventilating systems, distributing frames, repeating equipmets, switching equipments, etc. Grounding system of an ESS Office is most effective when all the ground points are connected to a single, common earth. The one point grounding prvides a common reference potential, keeping all the items of telecommunications facility free from the earth current and voltage hazards.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.325-329
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• 1994

This paper describes a compact design and control method of PWM inverter-mounted induction motor especially designed for reducing the size and weight considerably, which may be applied to the speed control system such as air conditionr,conveyor and textile mill, etc. To obtain higher power density without derating performance, a new mechanical configuration unifying the inverter circuit and motor is proposed. Also, through the use of current minimization control method during V/f operation it is possible to reduce the size of heat-sink related to the losses of power circuit. By the proposed design method, a compact inverter-mounted induction motor system of 1Hp is built and its validity can be verified through the experimental results.

• 한국잡초학회지
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• 제17권4호
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• pp.345-361
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• 1997

Photoassimilates translocate from regions of carbohydrate synthensis(source) to regions of carbohydrate utilization or storage(sink). In the source, assimilate loads into the phloem for long-distance transport. Current evidence suggests that there are twig loading mechanisms : one involves assimilate transfer via the apoplasm and then load into the phloem by carrier-mediated proton-sucrose cotransport, while the other involves movement through the continuous symplastic connections between the mesophyll cells and the phloem. Inspite of problems associated with the interpretation of experiments, the evidence for apoplastic loading remains convincing because the apoplastic loading systems explains well the observed accumulation capacity arid the selectivity of assimilate uptake by tile phloem.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1068-1070
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• 2000

This paper presents a method of designing the control loop for dc-to-dc converters when at characteristics of the converter's load are unknown. In the proposed method, a converter is considered as a stand-alone module that feeds a current sink load, and the control loop is designed in order to maximize the robustness of the converter's closed-loop performance. The proposed method yields a control design that provides predictable and controllable closed-loop performance for the converter loaded with an actual load.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.221-225
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• 2001

In the paper, we report on the DC and Thermal effect of the GaN based HFET. A physics-based a model was applied and found to be useful for predicting the DC performance and Thermal effect of the GaN based HFET by Various substrate. The performance of device on the sapphire substrates is found to be significantly improve compared with that of a device with an sapphire substrate. The peak drain current of the device achieved at HFET on the SiC substrate

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권12호
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• pp.559-561
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• 2003

We report a new excimer laser annealing method which successfully results in a single grain boundary formation in the channel of polycrystalline silicon thin film transistor. The proposed method is based on lateral grain growth and employs aluminum patterns which act as selective beam mask and lateral heat sink. The maximum grain size obtained by the proposed method is about 1.6${\mu}{\textrm}{m}$ in the length. The grainboundaries should be arranged parallel with the direction of current flow for the best device performance, so we propose a new device fabrication method and a new poly-Si TFT structure. Poly-Si TFT fabricated by the proposed method exhibits considerably improved electrical characteristics, such as high field effect mobility exceeding 240 $cm^2$/Vsec.