• Journal of electromagnetic engineering and science
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• v.1 no.2
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• pp.131-138
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• 2001

The DTV (Digital TV) tuner for an 8-VSB (Vestigial Side-Band) modulation was developed to meet the requirements of the ATSC (Advanced Television Systems Committee). The double frequency conversion and the active tracking filter in the front-end were used to cancel interferences between adjacent channels and multi-channels by suppressing the IF beat and the Image frequency. However, It was impossible to get frequency mapping between the tracking filter and the first VCO (Voltage Controlled Oscillator) in the existing DTV tuner structure which differs from the NTSC (National Television Systems Committee) tuner. This paper, therefore, suggests an assailable structure and a new method for the automatic frequency selection by mapping the frequency characteristics over the tracking voltage and the combined HW which is composed of a Micro-controller, an EEPROM (Electrically Erasable Programmable Read Only Memory), a DAC (Digital-to-Analog Converter), an OP amplifier, and a switch driver.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.5
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• pp.86-98
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• 1993

The application of A.C. motor for servo system is rapidly increased according to the recent advance of power electronics and digital control techniques. The induction motor which has a simple structure and needs less maintenance has become to be used widely in the industrial field for the speed and position control recently. In this paper, the full-bridge resonant inverter is applied to the speed control of single phase inducting motor. The digital PID control algorithm is used and the control parameter is determined by the Zigler-Nichols transient response method. The speed control is carried out by the one chip micro-processor(intel EV 8097BH) and control program is developed by the assembly language. By the experimental result, it is confirmed that the speed of single phase induction motor driven by full bridge series inverter can be smoothly controlled by a digital PID controller.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.73-78
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• 2012

Recently, the laser processing method has used as micro-machining technologies in industries of aerospace, electronics and automotive. The laser processing newly focused could be alternative to existing machining method. However, there are few practical results of research about the proper setting of the laser machining conditions and the laser machining characteristics for mechanical materials. The purposes of this study was to choose optimum machining conditions and to estimate the laser machining characteristics using taguchi experimental method for various mechanical materials that is S45C, Stainless steel, Aluminum, Copper, Titanium and Tungsten carbide. From obtained results, it was confirmed that optimum machining conditions could be found and laser machinability depends on thermal conductivity and hardness of workpiece.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.508-511
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• 2006

일반적으로 먀이크로 소스는 1kW $\sim$수 Mw의 용량을 가지며 종전의 대규모 전력설비와 비교하여 높은 신뢰도를 갖는 고품질의 전력을 공급할 수 있다. 본 연구에서는 소형 분산에너지원으로서 연료전지 마이크로 소스의 특성을 살펴보기 위하여 능동전력필터를 마이크로 소스와 병렬 연결하여 고조파 보상성능을 평가하였다. 본 연구는 PSIM상에서 구현하였으며 정상상태 및 과도상태에서 타당성을 입증하였다.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.11-15
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• 2002

Switched Reluctance Motor (SRM) offers the advantages of simple and robust motor construction, high speeds and high efficiencies over a wide operating range of torque and speed, excellent controllability. However, SRM has the disadvantages of high current harmonics, and low power factor because of a capacitor filter is inserted in the power converter and inductance of SRM is high, it has pulse waveform of current. This paper deals with an energy efficient converter fed SRM system with the reduced harmonics and improved power factor and with higher efficiency. The validity of the proposed scheme is verified via experiment. We are implemented the proposed control system using 80C196KC micro-controller.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.693-696
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• 2002

In this paper, network management system(NMS) was developed using Ethernet network for several devices. Recently, due to the development of the information communication, network has been constructed several place. And management system using network has been studied due to the increment of necessity of remote control for industrial device. Agent board that necessity of NMS, was developed using general micro-controller, it operates like stand-alone network device, supports TCP/IP protocol suite, has the ability to connect to industrial device and communicates each other. Also manager base on MMI was developed, it operates with agent board and supports effective management. To prove this system UPS(uninterruptible power supply) is selected as the example of industrial device. Finally, experimental result verifies the communication between agent board and manager.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.321-324
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• 1998

A single phase induction motor (SPIM) rated in fractional horsepower is widely used in home and industrial equipment: washing machines, fans, refrigerators, etc. In this paper, authors present the experimental results of the SPIM under controlling of currents of main and auxiliary windings by using a one-chip micro stator(OMS). This new starting method is developed to replace the conventional starting device consisted with a mechanical switch and a capacitor. In mentioned method, the soft-starting of SPIM is simply implemented and higher efficiency is obtained in comparison with conventional condenser type SPIM.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.674-677
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• 2002

Vertically aligned CNTs were grown on Fe-deposited $SiO_2$ substrates using thermal CVD of acetylene gas. The size of Fe particle is controlled by the flow rate of $NH_3$ and pretreatment time, which leads to control the diameter of CNTs. As the diameter of CNTs decreases, the growth rate is enhanced with an inverse dependence of the CNT diameter. The growth rate of CNTs increases linearly as the growth time increases until 30 min but is rapidly decreased over 40 min. We found an inverse relation between the diameter and growth rate of carbon nanotubes. As the diameter of CNTs increases, the compartment layers of bamboo-shaped CNTs appear more frequently. A base-growth model is suitable to explain the dependence of growth rate and structure of CNTs on the diameter size of catalytic particles.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.670-673
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• 2002

We have investigated the catalyst effect on the growth and structure of CNTs using thermal chemical vapor deposition. The respective growth rate of CNTs shows that the performance of catalysts is in the order of nickel (Ni)>cobalt (Co)>iron (Fe). The average diameter of CNTs follows the sequence of Fe, Co, and Ni catalysts. The structure of CNTs reveals almost same morphology regardless of catalyst but the crystallinity of CNTs is largely dependent on catalyst. The crystallinity of CNTs synthesized from Fe catalyst is higher than that from Ni or Co catalyst. We demonstrate that the growth rate, the diameter, and the crystallinity of CNTs can be manipulated by selecting the catalysts.

• Journal of Powder Materials
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• v.23 no.2
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• pp.170-176
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• 2016

Lithium-ion batteries (LIBs) are rapidly improving in capacity and life cycle characteristics to meet the requirements of a wide range of applications, such as portable electronics, electric vehicles, and micro- or nanoelectro-mechanical systems. Recently, atomic layer deposition (ALD), one of the vapor deposition methods, has been explored to expand the capability of LIBs by producing near-atomically flat and uniform coatings on the shell of nanostructured electrodes and membranes for conventional LIBs. In this paper, we introduce various ALD coatings on the anode, cathode, and separator materials to protect them and improve their electrochemical and thermomechanical stability. In addition, we discuss the effects of ALD coatings on the three-dimensional structuring and conduction layer through activation of electrochemical reactions and facilitation of fluent charge collection.