• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1684-1689
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• 2003

Dielectric Barrier Discharges (DBD) in oxygen and air are well established for the production of large quantities of ozone and are more recently being applied to a wider range of after treatment processes for HAPs(Hazardous Air Pollutants). The potential use as a charger for particle collection are not well known. In this work, we measured charge distribution of nanometer or submicron sized particles passing through the dielectric barrier discharge reactor. The bipolar charge characteristics of particles passing DBD reactor were investigated. Fluorometric method using uranine particles and a fluorometer was employed to examine the bipolar charging characteristics of the charged particles by DBD reactor. Finally, the charge distributions of particles were determined from the electrical mobility classification using DMA.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.172-176
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• 1999

에폭시 수지의 강인성 향상을 위하여 양말단에 아민 반응기를 가지는 PES-CTBN-PES triblock copolymer를 합성하여 이를 에폭시 수지의 강인화제로 사용하였으며 경화제로는 p-DDS(p-dichlorodiphenylsulfone)를 사용하였다. 또한 공중합체에 의한 물성 향상효과를 CTBN과 PES-NH$_2$의 블렌드에 의한 경우와 비교하였다. 강인화된 에폭시 수지의 물성은 강인성 및 굴곡특성을 측정하여 분석하였으며, 열특성은 DSC, TGA, 및 DMA에 의해 실시되었다. 그리고 강인화된 에폭시 수지의 강인성 향상 mechanism을 규명하기 위하여 파단면을 SEM으로 분석하여 상분리 거동을 고찰하였다. 높은 유리전이온도와 우수한 기계적 물성을 가지는 고성능 기능성 폴리설폰(PES-NH$_2$)과 상용 액상 고무 첨가제인 CTBN을 이용하여 합성된 공중합체를 강인화제로 사용함으로써 열안정성, 탄성률 및 내식성의 감소없이 에폭시 수지의 쳐대 단점인 강인성을 최적 수준으로 개선시킬 수 있었으며 공중합체의 에폭시 수지에 대한 우수한 용해도에 따른 가공성이 향상되었다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.9
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• pp.837-844
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• 2012

We considered an approach in terms of materials for improvement of insulation performance of vehicle rubber hoses. Ethylene propylene rubber(EPDM) for heater hoses in cooling system and acrylic rubber(AR) for intercooler hose in intake system were chosen for mixing for the vibration and noise performance. We modified EPDM and AR through changing compound of base polymer, reinforcement fillers and additives. Dynamic mechanical analysis(DMA) was used to measure viscoelastic properties such as shear modulus and loss factor($tan{\delta}$). Vehicle acceleration test was also conducted to observe indoor changes in insulation performance of hoses.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.833-836
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• 2001

The thermomechanical behaviors of the shape memory alloy were conducted through the finite element analysis of ABAQUS with UMAT user subroutine. The unified thermomechanical constitutive equation suggested by Lagoudas was adapted into the UMAT user subroutine to investigate the characteristics of the shape memory alloy. The three cases were solved to investigate the thermomechanical characteristics of the shape memory alloy. The material properties for the analysis were obtained by DSC and DMA techniques. According to the results, the thermomechanical characteristics, such as a shape memory effect and a pseudoelastic effect, could be obtained through the finite element analysis and the analysis results were revealed to agree well with the experimental results. Therefore, the finite element analysis using UMAT user subroutine is one of prominent analysis techniques to investigate the thermomechnical behaviors of the shape memory alloy quantitatively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.264-270
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• 1996

In this paper, a computer automated system has been developed for measuring the focal length of camera lens using the MTF(Modurar Transfer Function) based on the signal processing around a line CCD and autocollimator. An optical Path for the focal length measurement system has been designed around thelight sourec, collimator, camera, mirror and the line CCD. The eyepiece of the collimator is replaced byline CCD, and the mirror is moved along the focal axis by a PC driven step motor. An efficient method has been designed for finding the optimum MTF value for the focal length based on the least squares approach. The developed system is fullycomputer automated: signal transmission to and from the camera, MTF evaluation based on the line CCD, step motor contorl, etc. The developed system has been applied to a practical camera manufacturing process and demonstrated its performance

• Elastomers and Composites
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• v.48 no.4
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• pp.276-281
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• 2013

Polyester type polyurethane foam modified with acrylic polyol was prepared by quasi prepolymer method. Thermal and dynamic mechanical properties of polyurethane foam were analysed by thermal gravimetric analysis(TGA) and dynamic mechanical analysis(DMA). Also, glass transition temperature was measured by differential scanning calorimeter(DSC). As acrylic polyol contents were increased, thermal stability measured by TGA was slightly decreased. Storage modulus was increased and tan delta was decreased with increasing of acrylic polyol contents.

• Journal of the Korean Wood Science and Technology
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• v.37 no.2
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• pp.155-163
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• 2009

This study examined the thermal stability of PLA-WF bio-composites. Wood flour (WF)-filled PLA bio-composites were reinforced with the flame retardants, Melamine pyrophosphate (MPP), resorcinol bis (diphenyl phosphate) (RDP) and zinc borate (ZB). The flame retardant was compounded with PLA and natural biodegradable filler. The thermal properties of the biodegradable polymer and bio-composites reinforced with the flame retardant were measured and analyzed by DSC, DMA and TGA. The results showed that the flame retardant-reinforced biodegradable bio-composite exhibited improved thermal properties.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.221-224
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• 2001

A new code: LS code was proposed for IMT-2000 CDMA system. The code has special properties during a certain time of interval: 1) perfect autocorrelation 2) perfect crosscorrelation. The perfect autocorrelation means that the autocorrelation has nMaximum for zero time-offset and zero for other times during a certain time. Moreover the perfect crosscorrelation means that the crosscorrelation has zero during a time of interest. In the LAS-DMA system, the LS code is only used in the spreading of data bits in contrast to the conventional CDMA system. Therefore the LS code pair setting and allocation order should be dealt with carefully considering the special properties of LS code. This paper is intended as an investigation of the setting LS code pair and the sequential allocation method. Firstly, the optimum LS code pair set is proposed in order to minimize PAPR. Secondly, the sequential allocation method is studied to either minimize PAPR or expand IFW.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.77-81
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• 2006

Because of the rapid increasing of network user, there are some problems to tolerate the network overhead. Recently, the research and technology of the user-level for high performance and low latency than TCP/IP which relied upon the kernel for processing the messages. For example, there is an Infiniband technology. The Infiniband Trade Association (IBTA) has been proposed as an industry standard for both communication between processing node and I/O devices and for inter-processor communication. It replaces the traditional bus-based interconnect with a switch-based network for connecting processing node and I/O devices. Also Infiniband uses RDMA (Remote DMA) for low latency of CPU and OS to communicate between Remote nodes. In this paper, we develop the SRP (SCSI RDMA Protocol) which is Storage Access Protocol on Infiniband network. And will compare to FC (Fibre Channle) based I-SCSI (Internet SCSI) that it is used to access storage on Etherent Fabric.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.365-371
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• 2004

디지털 기술의 급속한 발전으로 디지털 방송에 대한 여러 가지 요소기술과DTV가 곧 상용화 될 전망이다. 본 연구는 대용량 DVD 저장매체를 이용하여 3D 1-n급 방송 스트림을 송출하기 위한 시스템 설계에 관한 것이다. HD급 방송 스트림을 위한 HDD 및 여러 가지 저장매체를 통해 영상 데이터를 억세스를 하지만 데이터 보관방법상의 문제점과 디스크의 원리상 데이터 억세스를 균일하게 처리하지 못하여 발생하는 인터페이스 동기 불일치 등의 문제점이 있다. 그러므로 DVD 매체를 통한 저장방법 및 억세스의 균일함을 제공하고, 송출 출력을 2.4Mpds 인터페이스 고정시켜 응용 프로그램에서 미디어 정보를 MMIO DMA방식으로 버퍼링하므로써 스트림을 재생할 때 동기 등의 문제점을 해결하였으며, 또한 PCI 컨트롤러는 FPGA VHDR coding하여 PC의 3D-Streamer 응용 프로그램의 명령 신호로 제어를 한다. 이 명령에 따라 3D-Streamer는 3차원 입체영상적인 영상출력을 SMTPE-310M으로 출력하거나 8 DVB 모드로 출력을 하게 된다. 따라서 DVD 전송 직병렬 인터페이스로서 다른 셋톱 장치 및 스트림 전송 장치와 데이터 호환을 이루게 된다.