• 전자공학회논문지
• /
• 제49권9호
• /
• pp.287-292
• /
• 2012

본 논문에서는 액체의 전기 전도도를 저잡음으로 검출하기 위하여 동기복조를 이용하는 전도도 검출기를 설계한다. 이를 위하여 검출기는 반송파 발생기, 전도도 검출 셀, 전류-전압 변환기 및 동기 복조기로 구성하며, 복조기의 대역폭을 조정하여 검출기의 신호 대 잡음비(SNR)를 개선함으로써, 액체의 극미한 전도도도 용이하게 측정할 수 있도록 한다. 이의 응용 예로써, 반도체 공정의 공기감시용 전도도 검출기를 동기복조를 이용하여 설계하며, 실험을 통하여 설계의 타당성을 확인한다. 실험 결과, 검출기는 설계 성능에 부합하는 특성을 나타내므로, 동기복조를 이용한 전도도 검출기는 액체의 극미한 전도도 측정에 유용하게 사용될 수 있음을 입증하였다.

• 센서학회지
• /
• 제28권6호
• /
• pp.355-359
• /
• 2019

Exosomes, known as nanoscale extracellular vesicles in the range of 30-150 nm, are known to contain clinically significant information. However, there is still insufficient information on exosomal membrane proteins for cancer diagnosis. In this work, we investigated the characteristics of the membrane proteins of exosomes shed by cultured breast cancer cell lines using a surface plasmon resonance (SPR) spectroscopy and pre-activated alkanethiols modified sensor chips. The antibodies of breast cancer biomarkers such as MCU-16, EpCAM, CD24, ErbB2, and CA19-9 were immobilized on the pre-activated alkanethiols surfaces without any activation steps. The purified exosomes were loaded onto each antibody surface. The affinity rank of the antibody surfaces was decided by the relative capture efficiency factors for the exosomes. In addition, an antibody with a relative capture efficiency close to 100% was tested with exosome concentration levels of 10⁴/µl, 10⁵/µl, and 10⁶/µl for quantitative analysis.

• 전자공학회논문지C
• /
• 제35C권2호
• /
• pp.29-35
• /
• 1998

This paper describes architectures and design of a SIMD type parallel image processing chip called SliM-II. The chiphas a linear array of 64 processing elements (PEs), operates at 30 MHz in the worst case simulation and gives at least 1.92 GIPS. In contrast to existing array processors, such as IMAP, MGAP-2, VIP, etc., each PE has a multiplier that is quite effective for convolution, template matching, etc. The instruction set can execute an ALU operation, data I/O, and inter-PE communication simulataneously in a single instruction cycle. In addition, during the ALU/multiplier operation, SliM-II provides parallel move between the register file and on-chip memory as in DSP chips, SliM-II can greatly reduce the inter-PE communication overhead, due to the idea a sliding, which is a technique of overlapping inter-PE communication with computation. Moreover, the bandwidth of data I/O and inter-PE communication increases due to bit-parallel data paths. We used the COMPASS$^{TM}$ 3.3 V 0.6.$\mu$m standrd cell library (v8r4.10). The total number of transistors is about 1.5 muillions, the core size is 13.2 * 13.0 mm$^{2}$ and the package type is 208 pin PQ2 (Power Quad 2). The performance evaluation shows that, compared to a existing array processors, a proposed architeture gives a significant improvement for algorithms requiring multiplications.s.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제27권5호
• /
• pp.453-456
• /
• 2001

Background: Autogenous alveolar bone cell transplantation may be suitable for tissue engineering for alveolar bone reconstruction. This study aimed to isolate human alveolar bone-derived cells (HABDCs) and to evaluate the ability of collagen gels to support HABDC proliferation and differentiation for human alveolar bone tissue engineering applications. Method: Cultures of primary HABDCs were established from alveolar bone chips obtained from 10 persons undergoing tooth extraction. These cells were expanded in vitro until passage 3 and used for the in vitro characterization of HABDCs and the in vitro analysis of collagen gels for alveolar bone tissue engineering. Results: Of the 10 attempts made to obtain HABDC cultures, eight were successful. HABDCs expressed the osteoblastic phenotype characterized by alkaline phosphatase activity, osteocalcin expression and the mineralization of the extracellular matrix in vitro. When seeded on collagen gels, HABDCs penetrated into the collagen gel matrices and proliferated inside the gels. Significantly, when HABDCs were embedded into the gels, collagen fibers and mineralization were produced within the gels. Conclusion: This study demonstrates the feasibility of using cultured HABDCs and collagen gels for human alveolar bone tissue engineering applications.

• 한국전기전자재료학회논문지
• /
• 제19권6호
• /
• pp.507-511
• /
• 2006

We investigated accelerated soft error rate (ASER) in static random access memory (SRAM) cells of thin film transistor (TFT) type. The effects on ASER by cell density, buried nwell structure, operational voltage, and polysilicon-2 layer thickness were examined. The increase in the operational voltage, and the decrease in the density of SRAM cells, respectively, resulted in the decrease of ASER values. The SRAM chips with buried nwell showed lower ASER than those with normal well structure did. The ASER decreased as the test distance from alpha source to the sample increased from $7{\mu}m\;to\;15{\mu}m$. As the polysilicon-2 thickness increased up to $1000\;{\AA}$, the ASER decreased exponentially. In conclusion, the best condition for low soft error rate, which is essential to obtain highly reliable SRAM device, is to apply the buried nwell structure scheme and to fabricate thin film transistors with the thick polysilicon-2 layer

• Journal of Communications and Networks
• /
• 제13권5호
• /
• pp.494-498
• /
• 2011

Satellite digital multimedia broadcasting (S-DMB) systems use gap fillers (GFs) to provide wireless multimedia services to non-line-of-sight locations. GFs act as repeaters, and S-DMB systems require GF networks in order to guarantee mobile reception. Each GF covers a cell or sector. In order to provide contiguous coverage of an area comprising two or more cells or sectors, multiple GFs are needed. However, when multiple GFs are situated close to each other, interference is likely to occur. As a result, in this study, we have investigated system-level environments for planning the design of interference-free GF networks in S-DMB systems. Our investigations revealed that S-DMB services are unavailable because of quality deterioration caused by interference when the delay attributable to a GF and the satellite signals exceeds ${\pm}$256 chips and the distance between the GF and its reception terminal is greater than 4.6 km. On the basis of this analysis, we conducted a field test that confirmed that the above-mentioned time delay can be controlled in such a way as to ensure high quality S-DMB services.

• 자원리싸이클링
• /
• 제31권1호
• /
• pp.3-11
• /
• 2022

실리콘은 지각에서 가장 풍부한 금속 원소이다. 금속급 실리콘(MG-Si)은 제강공정의 탈산제, 알루미늄 산업에서 합금 원소, 유기실레인 제조, 태양전지 등의 전자산업에 사용되는 전자급 실리콘 생산 등 산업적으로 널리 응용되는 중요한 금속이다. MG-Si는 전기 아크로에서 석탄, 코크스 또는 목재 칩의 형태인 탄소와 함께 이산화규소를 용융환원하여 만들어진다. MG-Si는 Siemens 공정과 같은 화학 처리를 통해 정제되며, 대부분의 단결정 실리콘은 쵸크랄스키 방식으로 만들고 있다. 이러한 제련 및 정제 방법은 2차 실리콘 자원으로부터 새로운 재활용 공정을 개발하는 데 기여할 수 있을 것이다.

• 한국식품과학회지
• /
• 제21권3호
• /
• pp.387-390
• /
• 1989

과채류 자동저장용 마이크로프로세서 제어장치를 활용하여 밀감의 저장시 발생되는 호흡량 및 중량감소를 자동 계측하였다. 중량감소는 스트레인게이지 load cell 장치를, 탄산가스는 적외선 가스분석기로 계측하고 계측신호를 컴퓨터에 접속하여 on-line화 하였다. 과일저장 조건과 계측시간 주기의 설정은 Z-80 마이크로프로세서와 컴퓨터간의 handshaking 정보교환 방식으로 수행할 수 있도록 하고 계측자료는 마이크로컴퓨터의 data file로써 자동기록 및 분석가능한 운영프로그램을 개발하였다. 건전한 것과 상처를 낸 감귤을 $20^{\circ}C$에서 4일간 저장하면서 호흡량을 비교하여 본 결과 건전한 감귤은 3-5ml $CO_2/kg{\cdot}hr$를 유지한 반면 상처를 낸 감귤의 경우는 50시간 이후부터 호흡량의 급격한 증가를 보였다. 한편 중량감소는 60시간 동안 건전한 감귤의 경우 거의 변화가 없었으나 상처를 낸 감귤의 경우 호흡량의 중가와 더불어 약 5%의 무게감소를 나타내었다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제10권5호
• /
• pp.263-271
• /
• 2006

Since astrocytes were shown to play a central role in maintaining neuronal viability both under normal conditions and during stress such as ischemia, studies of the astrocytic response to stress are essential to understand many types of brain pathology. The micro array system permitted screening of large numbers of genes in biological or pathological processes. Therefore, the gene expression patterns in the in vitro model of astrocytes following exposure to oxygen-glucose deprivation (OGD) were evaluated by using the micro array analysis. Primary astrocytic cultures were prepared from postnatal Swiss Webster mice. The cells were exposed to OGD for 4 hrs at $37^{\circ}C$ prior to cell harvesting. From the cultured cells, we isolated mRNA, synthesized cDNA, converted to biotinylated cRNA and then reacted with GeneChips. The data were normalized and analyzed using dChip and GenMAPP tools. After 4 hrs exposure to OGD, 4 genes were increased more than 2 folds and 51 genes were decreased more than 2 folds compared with the control condition. The data suggest that the OGD has general suppressive effect on the gene expression with the exception of some genes which are related with ischemic cell death directly or indirectly. These genes are mainly involved in apoptotic and protein translation pathways and gap junction component. These results suggest that microarray analysis of gene expression may be useful for screening novel molecular mediators of astrocyte response to ischemic injury and making profound understanding of the cellular mechanisms as a whole. Such a screening technique should provide insights into the molecular basis of brain disorders and help to identify potential targets for therapy.

• 대한기계학회논문집B
• /
• 제35권11호
• /
• pp.1127-1131
• /
• 2011

본 논문에서는 액적의 균형공급에 의해 관류유량이 일정하게 유지되는 펌프 없는 세포배양 칩을 제안하였다. 기존의 펌프 없는 세포배양 칩은 유체 수위차가 시간에 따라 점차 감소하여 일정한 관류유량 유지가 어려웠다. 반면, 제안된 칩은 액적의 균형공급으로 유체 수위차를 일정하게 유지하여 일정한 관류유량의 세포배양이 가능하다. 제작된 세포배양 칩의 성능분석 결과, 펌프 없이 최대 9.96%와 6.92% 의 편차 및 오차 내에서 0.1~$0.3{\mu}l$/min 의 관류유량, Q, 을 얻었다. H358 폐암 세포주 배양결과, Q=$0.2{\mu}l$/min 의 관류유량에서 최대 $57.8{\pm}21.1%$/일의 증식률을 보여, Q=$0{\mu}l$/min 의 정치배양보다 1.9 배 높은 값을 얻었으며 활성도 또한 정치배양보다 관류배양이 더 높은 값을 보였다. 제안된 펌프 없는 세포배양칩은 높은 증식률과 활성도의 좋은 배양환경을 제공하여 세포기반 바이오 분석에 응용 가능하다.