• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.229.1-229.1
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• 2015

생체 시료인 세포나 조직을 분석을 위해 임의로 파괴하거나 훼손하지 않은 본래의 상태에서 세포에 존재하는 다양한 생체분자 물질의 질량과 조성을 분석하고 영상화할 수 있는 대기압 표면 질량분석 이미징 기술을 개발했다. 생체 시료의 표면을 질량 분석을 하기 위해서는 대기압 분위기에서 시료에 열적 손상이 없는 조건으로 시편의 이온화 및 탈착 과정이 이루어지게 하기 위해 저온 대기압 탈착/이온화원으로 저온대기압 플라즈마 젯과 펨토초 적외선 레이저를 결합하여 대기압 이온화원을 제작하였다. 기존에 잘 알려진 저온 대기압 플라즈마 젯 소자는 유리관에 방전기체를 흘려주고 전극에 고전압을 인가하는 방식으로 제작했으며, 또 다른 대기압 이온화원으로서 근적외선 대역의 고출력 펨토초 레이저 빔을 현미경용 대물렌즈로 집속하여 생체시료에 조사시켰다. 수백 나노미터에서 수 마이크로미터 수준으로 빔을 집속할 수 있는 펨토초 레이저는 금나노로드의 도움으로 생체 시료를 매우 작은 수준으로 탈착하는 데 주로 사용하며, 수십 마이크로미터에서 수 밀리미터 정도의 크기를 가지는 저온 대기압 플라즈마 젯은 탈착된 물질을 이온화시키는데 사용하여, 이 두 가지 이온화원을 결합하여 이온화원으로 사용한다. 시료에서 발생한 이온을 질량분석기 입구까지 잘 끌고 갈 수 있도록 이온 전달관을 설계하고 보조펌프를 장착 사용한다. 이렇게 자체 개발한 대기압 이온화원을 상용 질량분석기기와 결합하여 대기압 분위기에서 시료의 표면을 질량분석할 수 있는 시스템과 측정 기술을 개발했다. 현미경 스테이지에 정밀 2-D 자동 스캐닝 스테이지를 장착하여 질량분석 정보에 공간 정보를 더할 수 있는 질량분석 이미징 기술 방법을 개발하여 생체 시편의 질량분석 이미징을 얻었다. 수분을 포함하는 생채시료로부터 단백질, 지질, 대사물질을 직접 분리하여 분석하는 이 새로운 질량분석법은 기존의 분석법에 비해 훨씬 더 많은 생체분자 정보를 얻을 수 있으며 공간정보를 더해 영상화할 수 있는 큰 장점이 있다. 대기압 표면 질량분석 기술은 생체시료를 파괴해서 용액화할 필요도 없으며, 진공 챔버에 넣기 위해 필요한 복잡한 전처리 과정 단계를 간략화 할 수 있으며 최종적으로는 살아있는 세포나 생체 조직도 정량 분석이 가능하여 생명과학 및 의료진단 분야에서 응용할 수 있는 분야는 무궁무진할 것이다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.927-933
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• 2011

This paper presents an optical sampling technique which can be used to overcome the limited bandwidth of a commercial electronic sampling oscilloscope for pulsed signal measurement. Employing an ultrafast laser with 0.1 ps pulse duration, 20 GHz electromagnetic pulses were generated through a fast photodiode. These pulses were transmitted through a microstrip line and sampled with an optically triggered electro-optic system. Two sampled 20 GHz pulses - measured independently over the transmission line with a non-contacting electro-optic method and conventional electronic one through a coaxial cable - were compared.

• Fire Science and Engineering
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• v.16 no.2
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• pp.1-7
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• 2002

In the normally, exit sign is always lighting on status by the connected to normal electrical source. So, there are happened to rise of the economical cost such as power consumption, maintenances and repair replacement of lamp etc. This paper are study on the new exit sign circuits by using high efficiency LED that is available for remote control and reduceible to power consumption, maintenance cost by the way of compensation fluorescent and incandescent lamps. As a results on the study, exit sign lamp is capable of control and supervisory in trigger angle by the remote control switch, widely and easily. And then, the response time was very fast in 600〔$\mu$s〕and also it can be find that the rising and fall time of oscillate circuit is maximum 200〔ns〕 as high sensitively. Finally, it obtain to the result that reducible of electrical power consumption and not required for replacement of lamp by using the high efficiency LED lighting source.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.265-274
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• 2016

In this study, the system was composed of the booster chopper and the power converter, which is a pulse width modulation (PWM) voltage inverter using a hybrid power generation system solar cell energy and wind force, Furthermore, in order to compensate the PWM voltage type inverter was linked with the general commercial power source, and through a normal operation of energy storage system (ESS), the system operated the LED Taxi Light by Wavelength according to Meteorological Changes at the airport in an efficient manner. The performance of the system was compared with the solar cell characteristics specification. In addition, for phase synchronization with the PWM voltage type inverter, the grid voltage was detected so as to operate the grid voltage and inverter output in the same phase and to connect the surplus electric power with the system. Finally, by developing a control circuit at the same time from which an excellent dynamic characteristics can be obtained through applying to the airport runway taxi light, it was concluded that a variety of taxi light can be pursued.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.182-187
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• 2009

In this paper, the power management module of wireless sensor node is designed and fabricated utilizing RF energy from reader antenna of commercial RFID system, which is mainly categorized in the energy harvesting. For this, the rectenna and the high efficient boost converter is designed to get the DC power from RF power for the charging the battery. When the RF power from RFID reader antenna is 1.2[W], the DC power of 3.1[mW] at the distance of 1[m] and 1[mW] at 5.5[m] are obtained. Considering the connection to the battery, the boost converter for enhancing the conversion efficiency is designed. The conversion efficiency at the distance of 4[m] is 79.3[%] and the harvested power is 1.36[mW] which is actually used for the charging the battery. This value is available in the wireless sensor networking.

• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.745-754
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• 2002

The Google search site (http://www.google.com), which was introduced in 1998, implemented the PageRank algorithm for the first time. PageRank is a ranking method based on the link structure of the Web pages. Even though PageRank has been implemented and being used in various commercial search engines, implementation details did not get documented well, primarily due to business reasons. Implementation techniques introduced in [4,8] are not sufficient to produce PageRank values of Web pages. This paper explains the techniques[4,8], and suggests major data structure and four implementation techniques in order to apply the PageRank algorithm. The paper helps understand the methods of applying PageRank algorithm by means of showing a real system that produces PageRank values of Web pages.

• Journal of the Korean Institute of Gas
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• v.10 no.3 s.32
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• pp.1-6
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• 2006

This paper presents the applicability of low caloric synthetic gas from coal gasification to a gas engine system and small sized generator. A commercial LPG engine is modified to use the low caloric synthetic gas from coal gasification as the gas engine fuel. The modification is focused on the fuel supplying system, which includes air flowrate adjusting orifice, gas mixer, vaporizer, preheater, regulators, and fuel tank. From the results of engine performance data, we have demonstrated that the engine modified by using the coal gasification gas is well operated from idle to wide open throttle conditions although the engine power is somewhat reduced relative to LPG fueled engine. And we have also demonstrated that the generator is well operated with various loads.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.593-600
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• 2014

This paper proposes a torque assist strategy for operating a hybrid agricultural tractor in the field. In general, different field operations such as baling and rotary tillage require different patterns and amounts of torque. Thus, a large agricultural tractor is used to improve the farming efficiency. Therefore, this research has the goal of developing a hybrid tractor that uses a small electric motor to provide additional torque for specific field operations. To achieve this objective, a rule-based torque assist strategy is proposed and validated for a simulation model in the Autonomie framework, which is a commercial simulation tool. Finally, the work efficiencies and fuel consumptions of a conventional tractor and the hybrid tractor with the proposed torque assist strategy are compared using simulations.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.649-656
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• 2012

The Global Positioning System (GPS) is widely utilized for commercial and military applications to estimate the location of the user or object. The GPS suffers from various intentional or unintentional interferers and it requires estimating the accurate angle-of-arrival (AOA) of the GPS signal to suppress interference signals and to efficiently detect GPS data. Since the power of GPS signal is very low comparing with the noise and interference signals, it is extremely difficult to estimate GPS AOA before despreading. Although AOA of GPS signal is usually estimated after despreading, it requires choosing the GPS AOA among results of AOA estimation because they include AOAs of interference and GPS signals when existing high-power interferers. In this paper, we propose the efficient choosing algorithm of the GPS signal among the estimated AOAs. The proposed algorithm compares the estimated results before despreading and after despreading for choosing AOA of GPS signal. Computer simulation examples are presented to illustrate the performance of the proposed algorithm.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.263-267
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• 2008

In this work the realistic install performance analysis of a helicopter was performed together with power extraction enabling to operate auxiliary system as well as intake pressure loss, loss due to bleed air, etc. which must be considered in practical propulsion system's performance modelling to be installed to the airframe. The pressure loss occurring in intake was estimated from the intake performance map with relationships of Mach Number and pressure loss. In order to evaluate the proposed installed performance model, the experimental data for comparison must be needed when mounted in propulsion system. However because of lack of accessibility to such real data at the moment, the alternative way was made through comparison that the analysis results by the proposed model were compared with a wellknown commercial program GASTURB's analysis results. The validity of the proposed installed performance model was consequently confirmed because its average deferences from the GASTURB's results were within 0.5%.