• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
• /
• pp.143-146
• /
• 2002

Unsized AS-4 carbon fibers were etched by RF plasma and then coated via plasma polymerization in order to enhance adhesion to vinyl ester resin. The gases utilized for the plasma etching were Ar, $N_2 and O_2$, while the monomers used for the plasma polymerization coating were acetylene, butadiene and acrylonitrile. The conditions for the plasma etching and the plasma polymerization were optimized by measuring interfacial adhesion with vinyl ester resin via micro-droplet tests. Among the treatment conditions, the combination of Ar plasma etching and acetylene plasma polymerization provided greatly improved interfacial shear strength (IFSS) of 69MPa compared to 43MPa with as-received carbon fiber. Based on the SEM analysis of failure surface and load-displacement curve, it was assume that the failure might be occurred at the carbon fiber and plasma polymer coating. The plasma etched and plasma polymer coated carbon fibers were subjected to analysis with SEM, XPS, FT-IR or Alpha-Step, and dynamic contact angles and tensile strengths were also evaluated. Plasma polymer coatings did not change tensile strength and surface roughness of fibers, but decreased water contact angle except butadiene plasma polymer coating, possibly owing to the functional groups introduced, as evidenced by FT-IR and XPS.

• 한국식품영양학회지
• /
• 제26권1호
• /
• pp.44-50
• /
• 2013

Quantitative analyses of naturally occurring methanol were performed for the alcoholic beverages commonly consumed in Jecheon, Chungbuk province, South Korea. The headspace analysis method was optimized for the low and high alcoholic beverages. The external standard method was applied due to the overlapping of 2-propanol and 2-butanol (the internal standard candidates) with target sample matrix peaks. The target samples were selected based on the retail sales amounts of alcoholic beverages in the largest retailer food-mart chain, Jecheon, Chungbuk province, South Korea. There was no sample containing methanol over 0.5 $mg/m{\ell}$, the Korean maximum level of methanol in alcoholic beverages (1.0 $mg/m{\ell}$ for fruit originated liquor etc). The total exposure amount of methanol via alcoholic beverages was estimated based on the daily alcohol consumption of 40 g. The hazard indices calculated by methanol RfD 0.5 mg/kg bw day (US EPA) and ADI 20 mg/kg bw day (proposed by Lachenmeier etc.) were 0.301 and 0.008, respectively. As with the hazard index, aggregate exposures below a HI of 1.0 will likely not result in adverse noncancer health effects over a lifetime of exposure. Then the methanol exposure via the alcoholic liquours might not hazard to Jecheon citizen.

• 대한원격탐사학회지
• /
• 제23권2호
• /
• pp.137-144
• /
• 2007

한국해양연구원에서는 2008년으로 예정된 통신해양기상위성의 발사에 맞춰 해색센서 데이터의 수신, 처리, 배포를 위한 해양위성센터 구축을 진행하고 있다. 해양위성센터의 위치는 전파 수신 환경 등의 조건을 고려하여, 5곳의 후보지 중 안산으로 정하였다. 수신시스템은 안테나와 RF로 나뉘어지며, 안테나는 위성으로부터 L밴드로 전송되는 센서데이터를 수신하기 위하여 직경 9m의 카세그레인식 안테나(G/T: 1.67GHz에서 19.35$(dB/^{\circ}K)$)로 설계하였다 RF는 다시 LNA와 다운컨버터로 구성되며 수평편파만을 분리해 모뎀으로 전송하도록 설계하였다. 기존 건물은 센터의 운용개념에 맞도록 전산실, 수전실, 상황실, 자료 처리실 등으로 내부 구조 변경 설계가 완료되었다. H/W및 N/W는 데이터의 수신, 처리, 배포에 효율성을 고려하여 6가지 세부 시스템으로 나누어 설계되었다. 가장 중요한 자료 배포 시스템은 위성을 통한 LRIT 배포 시스템과 인터넷을 통한 자료배포 시스템으로 구성된다. 또한 수신된 데이터를 1시간 내에 제공하기 위해 웹호스팅 등 외부데이터 제공 시스템도 구축하는 것을 추진 예정이다.

• 전자통신동향분석
• /
• 제25권5호
• /
• pp.97-105
• /
• 2010

모바일과 유비쿼터스 센서 네트워크 센서 시대가 도래함에 따라 가볍고, 작고, 얇고, 멀티기능을 구현할 수 있는 부품에 대한 요구가 증대하고 있다. 이에 대한 여러 가지 솔루션 중 MCM의 개념을 수직 방향으로 확장시킨 3D IC가 최근 각광을 받고 있다. 이는 물리적인 한계에 부딪힌 반도체 집적 공정의 한계를 극복하여 지속적으로 무어의 법칙에 맞춰 집적도를 향상시킬 수 있을 뿐만 아니라 소재와 공정이 달라도 3차원적으로 집적이 가능하여 메모리와 프로세서로 대표되는 디지털 칩뿐만 아니라 아날로그/RF, 수동소자, 전력소자, 센서/액추에이터, 바이오칩 등을 하나로 패키징 할 수 있는 장점이 있기 때문이다. 이를 통해 성능 향상, 경박단소, 저비용의 부품 개발이 가능하기 때문에 미국, 유럽, 일본 등 선도국뿐만 아니라 싱가포르, 타이완, 중국 등에서도 활발한 연구가 진행되고 있으며 CMOS 이미지 센서 모듈 생산에 TSV 기술이 이미 적용되고 있다. 본 고에서는 3D IC를 위한 TSV 및 적층 요소 기술을 소개하고 이를 통해 개발된 사례와 표준화 동향에 대하여 소개하고자 한다.

• 한국세라믹학회지
• /
• 제46권1호
• /
• pp.10-15
• /
• 2009

We have fabricated silicon-rich silica thin films via RF magnetron sputtering using a SiO target. Thickness evolution and microstructure change of such $SiO_x$ (1$SiO_x$ thin films turned out to be mainly responsible for the increase of refractive index.

• Journal of information and communication convergence engineering
• /
• 제8권1호
• /
• pp.77-82
• /
• 2010

Residential network is the hybrid technology of wireless, Ethernet, Bluetooth and RF to the internet via broadband connection at home to facilitate the convenient, safe and pleasant daily lives of home user with various home network services regardless of device, time and place. For ubiquitous development more devices will be wireless and most of them will be roaming. Since these roaming devices carry private information of daily life of residential users, the interaction among the roaming devices of residential network must be secure. This paper presents to secure registration of roaming devices using IP Security (IPSec) Protocol Suite without the need to trust foreign agents.

• 한국정밀공학회지
• /
• 제20권5호
• /
• pp.124-131
• /
• 2003

As the new model development lead time becoming shorter and the market requirements becoming more strict, automobile manufacturer begins to utilize 3-dimensional CAD system based techniques such as DMU (Digital Mock-up), Rf (Rapid Prototyping), VE (Virtual Engineering) to meet the market trends. But, no satisfactory utilities have been developed yet, to represent emotional properties such as embossment on the surface of interior parts, touch originated from material characteristics in virtual environment, so it is inevitable to manufacture prototype parts to verify actual feeling which passengers feel in automobile. This paper suggests a methodology to enhance the human sensitivity via embodying embossment on the surface of prototype car interior trim without deterioration of dimensional accuracy using RIM (Reaction Injection Molding) and thermoforming method.

• 제어로봇시스템학회논문지
• /
• 제16권4호
• /
• pp.374-380
• /
• 2010

This paper proposes a wearable interface for a tendon-driven robotic hand prosthesis. The proposed interface is composed of a dataglove to measure finger and wrist joint angle, and a micro-control board with a wireless RF module. The interface is used for posture control of the robotic hand prosthesis. The measured joint angles by the dataglove are transferred to the main controller via the wireless module. The controller works for directly controlling the joint angle of the hand or for recognizing hand postures using a pattern recognition method such as LDA and k-NN. The recognized hand postures in this study are the paper, the rock, the scissors, the precision grasp, and the tip grasp. In experiments, we show the performances of the wearable interface including the pattern recognition method.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
• /
• pp.54-58
• /
• 2002

This paper describes the theoretical analysis and performance of a 2.4㎓ bulk-driven downconversion mixer, where the LO signal is input via the bulk. A mixer core designed with a 0.18$\mu\textrm{m}$ CMOS process is able to operate under 0.8V∼1V supply voltage. The RF, LO, and IF port frequencies are 2.45㎓, 2.4㎓, and 50MHz, respectively. The measurement results exhibit conversion gain of -1.8㏈, l㏈ compression point of -17㏈m and IIP3 of -4㏈m with 0㏈m LO power. The power consumption is as small as 4mW.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
• /
• pp.189-192
• /
• 2001

We have studied fabrication processes that form asymmetric $\Gamma$-gate with a 0.1${\mu}{\textrm}{m}$ gate length in MMIC's(Monolithic Microwave Integrated Circuits). Asymmetric $\Gamma$-gate was fabricated using mixture of PMMA and MCB. Thus pseudomorphic high electron mobility transistor (PHEMT's) with 0.1${\mu}{\textrm}{m}$ gate length was fabricated via several steps such as mesa isolation, metalization, recess, passivation. PHEMT's has the -1.75 V of pinch-off voltage (Vp), 63 mA of drain saturation current(Idss and 363.6 mS/mm of maximum transconductance (Gm) in DC characteristics and current gain cut-off frequency of 106 GHz and maximum frequency of oscillation of 160 GHz in RF characteristics.