• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.369-373
• /
• 2005

To investigate the mechanism of ballast-flying phenomena by strong wind induced by high-speed trains, wind velocity in the vicinity of the track has been measured using 16-channel Kiel-probe array and detailed flow structure near the surface of the track has been analyzed. The position at which the underflow fully develop has been examined in order to assess the driving force of the turbulent flow under train and the results yields that the turbulent flow owing to the cavity of the inter-car as well as the friction force at the underbody of the train is the main reason of the strong wind under high-speed train. The preceding wind tunnel test results has been introduced to assess the probability of ballast-flying during the passage of the high-speed train by comparing the results from field-measuring. The results shows that when the G7 train as well as the KTX train runs at 300km/h, about 25m/s wind gust is induced just above the tie and the probability for small ballast under 50g to fly is about 50% when it is on the tie. If the G7 train runs at 350km/h, the wind gust just above the tie increases to 30m/s, therefore more radical countermeasure seems to be needed.

• 한국전기전자재료학회논문지
• /
• 제23권6호
• /
• pp.481-486
• /
• 2010

ENIG (electroless Ni immersion gold) is one of surface finishing which has been most widely used in fine pitch SMT (surface mount technology) and BGA (ball grid array) packaging process. The reliability for package bondability is mainly affected by interfacial reaction between solder and surface finishing. Since the behavior of IMC (intermetallic compound), or the interfacial reaction between Ni and solder, affects to some product reliabilities such as solderability and bondability, understanding behavior of IMC should be important issue. Thus, we studied the properties of ENIG with P contents (9 wt% and 13 wt%), where the P contents is one of main factors in formation of IMC layer. The effect of P content was discussed using the results obtained from FE-SEM(field-emission scanning electron microscope), EPMA(electron probe micro analyzer), EDS(energy dispersive spectroscopy) and Dual-FIB(focused ion beam). Especially, we observed needle type irregular IMC layer with decreasing Ni contents under high P contents (13 wt%). Also, we found how IMC layer affects to bondability with forming continuous Kirkendall voids and thick P-rich layer.

• The Korean Journal of Pain
• /
• 제26권3호
• /
• pp.249-254
• /
• 2013

Background: The pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinosus muscles on the medial side of the tibia, but it can lie in different sites in the medial knee. Accurate diagnosis of the position of the bursa is critical for diagnostic and therapeutic goals. The aim of this study was to evaluate sonoanatomic variations of the pes anserine bursa in the medial knee. Methods: One hundred seventy asymptomatic volunteers were enrolled in this study. Using ultrasound imaging (transverse approach, 7-13 MHz linear array probe) the sonoanatomic position of the pes anserine bursa and its relation to the pes anserine tendon were evaluated. Additionally, we evaluated the sonoanatomic variation of the saphenous nerve. Results: The position of the pes anserine bursa was between the medial collateral ligament and the pes anserine tendons in 21.2%/18.8% (males/females) of subjects; between the pes anserine tendons and the tibia in 67.1%/64.7% (m/f); and among the pes anserine tendons in 8.2%/12.9% (m/f). No significant differences in the position of the bursa existed between males and females. The saphenous nerve was found within the pes anserine tendons in 77.6%/74.1% (m/f) of subjects, but outside the pes anserine tendons in 18.8%/15.3% (m/f). Visibility of sonoanatomic structures was not related to either gender or BMI. Conclusions: Ultrasound provides very accurate information about variations in the pes anserine bursa and the saphenous nerve. This suggests that our proposed ultrasound method can be a reliable guide to facilitate approaches to the medial knee for diagnostic and therapeutic objectives.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 C
• /
• pp.1921-1923
• /
• 2001

In this work, an array of resistance temperature detector(RTD) was fabricated inside the microchannel in order to investigate in-situ flow characteristics. A rectangular straight microchannel, integrated with RTD's for temperature sensing and a heat source for generating the temperature gradient along the channel. were fabricated with the dimension of $200{\mu}m(W){\times}{\mu}m(D){\times}$48mm(L), while RTD measured precise temperatures at the inside-channel wall. 4" $525{\pm}25{\mu}m$ thick P-type <100> Si wafer was used as a substrate. For the fabrication of RTDs. 5300$\AA$ thick Pt/Ti layer was sputtered on a Pyrex glass wafer. Finally, glass wafer was bonded with Si wafer by anodic bonding, therefore RTD was located inside the microchannel. The temperature distribution inside the fabricated microchannel was obtained from 4 point probe measurements and Dl water is used as a working fluid. Temperature distribution inside the microchannel was measured as a function of mass flow rate and heat flux. As a result, precise temperatures inside the microchannel could be obtained. In conclusion, this novel temperature distribution measurement system will be very useful to the accurate analysis of the flow characteristics in the microchannel.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2012년도 추계학술대회
• /
• pp.307-311
• /
• 2012

본 논문에서는 금속 환경에서 사용이 가능한 RFID 국제 규격인 910MHz 대역에서 최상의 성능을 갖는 미앤더 형태의 마이크로스트립 패치 안테나를 설계하였다. 안테나에 부착되는 상용 태그 칩과 정합을 위해 사각 형태의 급전부를 본체에 연결하였으며, 사각 형태의 급전부를 본체 안에 위치하였고, 안테나의 복수부인 본체를 효과적으로 축소하기 위하여 패치의 소자를 증가시켜 다중의 미앤더 형태로 설계하였다. 제안된 안테나의 크기와 접은 횟수에 따른 대역폭, 효율, 인식 거리 등의 특성을 비교 분석하였다. 측정결과 안테나의 크기와 미앤더 형태로 접은 횟수에 따른 효율 및 이득 특성 변화가 안테나의 인식 거리에 큰 영향을 미치는 것을 확인하였다.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2012년도 추계학술대회
• /
• pp.316-319
• /
• 2012

본 논문에서는 IE3D를 기반으로 하는 새로운 PSO를 사용해 이동통신용 마이크로스트립 패치 안테나를 설계하였다. 본 논문의 목적은 이동통신용 급전 사각형 마이크로스트립 안테나를 설계하고, 대역폭의 복사 매개변수에 대한 안테나 크기(길이, 폭) 및 기판 매개변수 상대 유전 상수(${\varepsilon}r$), 기판 두께의 영향을 연구하여 이동통신용에 적합한 안테나를 설계하는 것이다. 안테나 설계 시 대역폭 확보 및 성능 향상을 위해 이중대역 이중 편파 안테나를 사용하였고, 안테나 위상 배열이 용이 하도록 단일 급전 방식을 사용하였다.

• 한국통신학회논문지
• /
• 제29권2A호
• /
• pp.147-156
• /
• 2004

본 논문은 CDMA2000 1X 신호 환경에서 동작하는 스마트 안테나 기지국의 각 안테나 소자에서 수신된 독립적인 신호를 이용하여 다이버시티 이득을 얻는 액세스 채널 복조기를 구현하고 구현된 복조기의 성능을 분석한다. 제안된 액세스 채널 복조기는 4개의 핑거를 지원하는 탐색기와 왈쉬 복조기 그리고 복조 제어기로 구성되고, 이들은 Alters사의 백만 게이트급 FPGA인 APEX EP20K1000EBC652와 TI사의 TMS320C6203으로 구현되었다. 제안된 액세스채널 복조기는 스마트 안테나 기지국이 최적의 웨이트 벡터를 얻을 수 없는 액세스 상태에서 데이터 복조 성능을 증가시키는 것이다. 본 논문에서는 실증시험을 통해서 위상 다이버시티 기법이 적용된 액세스채널 복조기의 성능이 기존의 액세스채널 복조기보다 우수함을 액세스 프로브 검출 확률, 액세스 실패 확률, 왈쉬 복조기에서의 $E_{b/}$ $N_{o}$ 항목에서 확인하였다.다.

• Journal of Microbiology and Biotechnology
• /
• 제16권2호
• /
• pp.256-263
• /
• 2006

In the model legume Medicago truncatula, two mutants, sickle and sunn, exhibit morphologically and genetically distinct hypernodulation phenotypes. However, efforts to isolate the single recessive and single semidominant genes for sickle and sunn, respectively, by map-based cloning have so far been unsuccessful, partly due to the absence of clones that enable walks from linked marker positions. To help resolve these difficulties, a new bacterial artificial chromosome (BAC) library was constructed using BamHI-digested genomic fragments. A total of 23,808 clones were collected from ligation mixtures prepared with double-size-selected high-molecular-weight DNA. The average insert size was 116 kb based on an analysis of 88 randomly selected clones using NotI digestion and pulsed-field gel electrophoresis. About 18.5% of the library clones lacked inserts. The frequency of the BAC clones carrying chloroplast or mitochondrial DNA was 0.98% and 0.03%, respectively. The library represented approximately 4.9 haploid M. truncatula genomes. Hybridization of the BAC clone filters with a $C_{0}t-l$ DNA probe revealed that approximately 37% of the clones likely carried repetitive sequence-enriched DNA. An ordered array of pooled BAC DNA was screened by polymerase chain reactions using 13 sequence-characterized molecular markers that belonged to the eight linkage groups. Except for two markers, one to five positive BAC clones were obtained per marker. Accordingly, the sickle- and sunn-linked BAC clones identified herein will be useful for the isolation of these biotechnologically important genes. The new library will also provide clones that fill the gaps between preexisting BAC contigs, facilitating the physical mapping and genome sequencing of M. truncatula.

• 한국발생생물학회지:발생과생식
• /
• 제16권1호
• /
• pp.59-67
• /
• 2012

Previously, we found that $Zap70$ (Zeta-chain-associated protein kinase) expressed in the mouse oocytes and played significant role in completion of meiosis specifically at MI-MII (metaphase I-II) transition. Microinjection of $Zap70$ dsRNA into the cytoplasm of germinal vesicle oocyte resulted in MI arrest, and exhibited abnormalities in their spindles and chromosome configurations. The purpose of this study was to determine the mechanisms of action of $Zap70$ in oocyte maturation by evaluating downstream signal networking after $Zap70$ RNAi (RNA interference). The probe hybridization and data analysis were used by Affymetrix Gene Chip Mouse Genome 430 2.0 array and GenPlex 3.0 (ISTECH, Korea) software, respectively. Total 1,152 genes were up (n=366) and down (n=786) regulated after $Zap70$ RNAi. Among those genes changed, we confirmed the expressional changes of the genes involved in the regulation of actin cytoskeleton and MAPK (mitogen-activated protein kinase) signaling pathway, since the phenotypes of $Zap70$ RNAi in oocytes were found in the changes in the chromosome separation and spindle structures. We confirmed the changes in gene expression in the actin skeletal system as well as in the MAPK signaling pathway, and concluded that these changes are main cause of the aberrant chromosome arrangement and abnormal spindles after $Zap70$ RNAi.

• 한국전자파학회논문지
• /
• 제18권3호
• /
• pp.257-264
• /
• 2007

본 논문은 IEEE 802.11a의 표준 규격$(5.15\sim5.25\;GHz,\;5.25\sim5.35\;GHz,\;5.725\sim5.825\;GHz)$을 하나로 통합할 수 있는 광대역, 고이득 안테나를 설계 및 제작하였다. 광대역 구현을 위해 사각 패치에 평행한 이중 슬롯을 삽입하였으며, 동축 프로브 급전 방식을 적용하여 슬롯에 의한 정전 성분을 상쇄시키고, $\lambda_g/4$ 임피던스 변환기를 Taper형 선로로 구성하여 광대역 임피던스 정합이 용이하게 하였다. 안테나의 이득을 개선하기 위하여 $2\times2$ 배열 구조로 최종 설계하였으며, 최종 제작한 안테나는 $5.01\sim5.95\;GHz(B/W\doteqdot940\;MHz)$ 대역에서 return loss -10 dB 이하의 양호한 반사 손실과 13 dBi 이상의 높은 이득을 얻을 수 있었다.