• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3866-3872
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• 2010

This paper presents a design of high power oscillator using a spiral resonator and high power transistor with measurement. Even lots of drawbacks are known in design of oscillators using high power transistors, the spiral resonator is adopted because it has relatively high Q out of planar resonators. The designed power oscillator at 1.8GHz is fabricated and tested. Measurement shows the obtained output power is 23.5dBm at 1.74GHz with -146.76dBc/Hz of phase noise at 1MHz offset. In addition, it is illustrated that the frequency stability is excellent with the shift less than 1MHz and the measured maximum output power is around 24dBm when the bias voltages are adjusted.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.91-91
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• 2004

과학기술위성 1호의 탑재체는 원자외선 분광기(FIMS), 우주물리 관측기(SPP), 자료수집 시스템(DCS), 그리고 고정밀 별감지기(NAST)가 있으며, 우주물리 관측기는 저에너지 검출기(ESA), 고에너지 검출기(SST), 랑마이어 탐침(LP)과 자기력 측정기(SMAG) 등 4개의 센서로 구성되어있다. 위성에 탑재된 각각의 관측기는 운용시 발생되는 데이터를 위성의 대용량 메모리 시스템에 저장되며, 위성이 한반도 상공을 지나는 교신구간에 X-Band 대역의 RF를 통하여 지상으로 전송된다. (중략)

• Development and Reproduction
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• v.11 no.1
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• pp.43-47
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• 2007

Smad proteins mediate transforming growth $factor(TGF)-{\beta}$ signaling and play a pivotal role in embryonic development. The estrogen receptor-related receptors(ERRs), which are structurally similar to estrogen receptors, are members of orphan nuclear receptor in the nuclear receptor superfamily and their functions are known to be involved in the formation of extra-embryonic ectoderm. To investigate the involvement of Smad3 and $ERR{\beta}$ like 1 in reproductive activities and embryogenesis in marine invertebrate, we examined gene expression of Smad3 and $ERR{\beta}$ like 1 in Strongylocentrotus nudus during their seasonal changes and embryonic development using real-time polymerase chain reaction. The Smad3 mRNA levels in gonad showed an increasing pattern from February to June 2004 but decreased at August(spawning season) followed by an elevation of the levels at October and December 2004. The mRNA levels of the $ERR{\beta}$ like 1 significantly elevated during the spawning season. During embryonic development, Smad3 mRNA levels at $8{\sim}16$ cell stages were significantly higher than those of other stages, whereas the mRNA of the $ERR{\beta}$ like 1 was significantly high levels at late development stages, i.e., blastular, gastrula and plutei stages. These results suggest that the Smad3 could be involved at least in part in the early cleavage stages and the $ERR{\beta}$ like 1 may play an important role in the spawning season and late developmental stage in the sea urchin.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.45-52
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• 2020

Hypertension often leads to cardiovascular disease and kidney disease, and hypertention is an important worldwide problem. Body mass index (BMI) has an important role for raising blood pressure. Further, hypertension can be affected by both environmental factors and genetic factors. Many single nucleotide polymorphisms have been associated with hypertension. Genome wide association study (GWAS) is a method of confirming a new locus of increasing the risk of disease, and GWAS has confirmed several single nucleotide polymorphisms (SNPs) that are associated with high blood pressure. This study analyzed the relationship between systolic blood pressure, diastolic blood pressure and SNP of the ATP2B1 gene in 994 Koreans. SNPs that showed the highest statistical significance with systolic and diastolic blood pressures were selected on the multiple linear regression analysis. One-way analysis of variance for systolic and diastolic blood pressures was performed, and multiple logistic regression analysis was performed on the risk of hypertension. The P values were two-tailed, and P<0.05 was considered significant. Four SNPs were associated with systolic blood pressure and six SNPs were associated with diastolic blood pressure. In addition, a genotype-based analysis showed significant odds ratios for the risk of hypertension in older men (adjusted OR, 5.743; 95% CI, 1.173~28.121; P=0.031). This study suggests that the ATP2B1 variants affect both the systolic and diastolic blood pressure.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.3
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• pp.212-219
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• 1985

The field experiment was conducted to study on the growth analysis of early variety, MTC-1, and late variety, Suweon 19, in response to seeding time at Suweon. The results summarized as follows: 1. Days required for Leaf-Formation(L-phase) of MTC-1 and Suweon 19 was same but that of Node-Thickening(N-phase) was quite different, e.g. late variety has two times longer. The period of Ear-Development (E-phase) in MTC-1 was 41 days and 53 days in Suweon 19. L-and N-phase were shortened by late seeding but E-phase was not influenced by seeding time. 2. Leaf Area Index(LAI) was decreased and Leaf Area Ratio(LAR) was increased by late seeding. Days required to maximum LAR was less by late seeding. Net Assimilation Rate(NAR) of L-, N-, and E-phase was decreased but its tendency in E-phase was remarkable at late seeding. 3. Crop Growth Rate(CGR) was increased gradually in the process of plant growth and it was the highest at Husk-stage. Relative Growth Rate(RGR) was increased in L-phase and was decreased in N- and E-phase, but its tendency in N-phase was great. 4. The period required to the maximum dry matter yield was shortened by late seeding and dry matter yield was increased by early seeding.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.129-134
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• 2014

This paper presents a 10-bit 10-MS/s asynchronous successive approximation register (SAR) analog-to-digital converter (ADC) which consists of a digital-to-analog converter (DAC), a SAR logic, and a comparator. The designed asynchronous SAR ADC with a rail-to-rail input range uses a binary weighted DAC using metal-oxide-metal (MOM) capacitor to improve sampling rate. The proposed 10-bit 10-MS/s asynchronous SAR ADC is fabricated using a 0.18-${\mu}m$ CMOS process and its active area is $0.103mm^2$. The power consumption is 0.37 mW when the voltage of supply is 1.1 V. The measured SNDR are 54.19 dB and 51.59 dB at the analog input frequency of 101.12 kHz and 5.12 MHz, respectively.

• The Korean Journal of Financial Management
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• v.25 no.3
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• pp.131-153
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• 2008

This paper calculates the Risk Index of Korean securities industry that summarizes the information contained in seventeen financial indicators that represent risk categories such as capital adequacy(C), asset quality(A), earnings(E), and liquidity(L) by using the NBER statistical methodology. For the validation of Risk Index, expected default frequency has been used, and the result has been proved to be positive. According to the compiled Risk Index, the level of risks of Korean securities industry has been decreasing from the second quarter of 2003 to the first quarter of 2006 by 22 percent. But the risk has been increasing during the periods from the first quarter of 2002 to the first quarter of 2003 and from the first quarter of 2006 to the last quarter of 2006.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.39.1-39.1
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• 2009

본 실험은 연성과 광 투명도가 뛰어난 아크릴 (PMMA) 과 폴리카보네이트 (Polycabonate) 기판의 축전 결합형 플라즈마 (CCP) 건식 식각 연구에 관한 것이다. 특히 식각 반응기 내부의 압력 변화에 따른 두 기판의 건식 식각 특성 분석에 초점을 맞추었다. 실험에 사용된 기판은 두께 1mm의 아크릴 (PMMA) 과 폴리카보네이트 (Polycabonate)를 $1.5\times1.5\;cm^2$로 절단하여 Photo-lithography 공정을 통하여 감광제 (Photo-resist)로 패턴하였다. 식각 반응기 내부에 패턴 된 아크릴(PMMA) 과 폴리카보네이트 (Polycabonate)를 넣은 후 반응기 내부 진공 상태로 만들었다. 그 후 5 sccm $O_2$ 가스를 유량조절기 (Mass flow controller)를 통하여 식각 반응기 내부로 유입하여 실험을 하였다. 이때 식각 공정 변수는 식각 반응기 내부 압력과 샘플 척 파워이다. 특성평가 항목은 식각 후 기판 (Substrate)의 식각율 (Etch rate), 식각 선택비 (Selectivity) 그리고 기판 표면 거칠기 (RMS roughness)이다. 실험 결과는 표면 단차 분석기(Surface profiler)를 이용하여 기판 (Substrate)의 표면을 분석 하였다. 또한 OES (Optical Emission Spectroscopy) 를 이용하여 식각 중 내부 플라즈마의 상태를 분석하였다. 본 실험 결과에 따르면 5 sccm $O_2$ 가스와 100 W 척 파워를 고정한 후 반응기 내부의 압력을 25 mTorr에서 180 mTorr까지 변화시켜 실험한 결과 40 mTorr의 반응기 내부 압력에서 실험 자료 중 가장 높은 식각율로 아크릴 (PMMA)은 $0.46\;{\mu}m/min$, 폴리카보네이트 (Polycabonate)는 $0.28\;{\mu}m/min$의 결과를 얻었다. 또한 이 자료를 바탕으로 5 sccm $O_2$ 가스와 반응기 내부 압력을 40 mTorr로 고정시키고 RIE 척 파워를 25 W에서 150 W로 증가시켰을 때 아크릴 (PMMA)의 식각율은 $0.15\;{\mu}m/min$에서 $0.72\;{\mu}m/min$까지 증가하였고, 폴리카보네이트 (Polycabonate) 의 식각율은 $0.1\;{\mu}m/min$에서 $0.36\;{\mu}m/min$까지 증가하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.1011-1016
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• 2001

In this paper, a narrow-band bandpass filter using microstrip open-loop resonators with coupled and crossing lines is designed and fabricated. This filter has many advantages such as compact in size, low weight and the characteristic of the elliptic-function narrow-band bandpass filtering. The configuration consists of two identical microstrip open loop resonators, coupled line and crossing line. By using open loop resonators, the size of the filter can be reduced about 50% compared with the ring resonators. A crossing line gives two notchs in the stopband, which have sharp selectivity in the passband. Centered at 2.455GHz, the calculated microstrip bandpass filter shows a bandwidth of 1.22%, which makes it very attractive for application in the wireless LAN. The filter is fabricated by photo-etching process. The fabricated bandpass filter shows that the bandwidth is 0.85% for 2.458GHz and the size is only $2.6cm\times1cm$.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.23-23
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• 2003

Cu 단결정과 다결정 Cu 막대(rod)를 시료로 하여 구부린 완전결정(bent perfect crystal, BPC)을 이용한 중성자 단색기의 특성을 평가함으로써 단결정 회절 및 집합조직 측정장치인 4축 단결정 회절장치(FCD)에 BPC 단색기를 적용할 수 있는지 시험하였다. 측정은 한국원자력연구소의 연구용 원자로인 하나로의 571 수평공에 구성된 test station에서 수행하였다. 단색기와 시료 사이의 거리는 3000mm, 시료와 검출기 사이는 600mm, 단색화빔 인출각도(2θ/sub M/)는 44.6°로 고정하여 FCD와 거의 같은 배치를 구현하였다 직사빔의 단면분포와 강도는 저효율 2차원 위치민감형 검출기(2-D PSD)를 이용하여 확인하였다. 이 검출기는 검출면적 90x90㎟, 공간 분해능 1.2mm, 검출효율 약 1%인 저효율 검출기이다. 회절빔은 검출면적 190x190㎟, 검출효율은 1Å에서 60%인 고효율 2-D PSD를 이용하여 측정하였다. Cu 단결정 측정에 사용한 ePC 단색화 결정은 200×40×3.4㎣ 크기의 Si(220) 슬랩이며, 비대칭 기하로 Si(331)면을 사용하여 파장 λ=0.954Å으로 중성자빔을 단색화시켰다. BPC-Si를 구부려 슬랩의 곡률반경을 변화시키면서 단색기-시료-검출기가 평행배치일 때 Cu(200), (220), (400), (420)면의 rocking curve를 측정하여 각 조건에서의 분해능과 강도를 평가하였다. BPC 단색기를 집합조직 측정에 적용할 수 있는지 시험하기 위하여 다결정 Cu 막대(직경 4.5mm, 길이 18mm)를 시료로 선택하였다. 207x30x3.0㎣ 크기의 Si 슬랩을 단색화 결정으로 사용하였다. 이 슬랩은 다양한 결정면을 이용한 특별한 기하를 구현할 수 있도록 Si(111)면에서 10° 벗어난 면을 절단한 것이다. 비대칭 기하로 Si(311)면을 사용하여 파장 λ=1.253Å의 단색화된 중성자빔으로 측정하였다 BPC-Si를 구부려 슬랩의 곡률반경을 변화시키면서 단색기-시료-검출기가 평행파 반평행배치일 때 Cu(111), (200), (220), (311), (331), (420)면의 회절선을 측정하여 각 조건에서 분해능과 강도를 평가하였다.