• 한국표면공학회지
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• 제47권5호
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• pp.221-226
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• 2014

A low temperature plasma nitrocarburizng was implemented on the duplex stainless steel to achieve the enhancement of surface hardness without degradation of its corrosion resistance. Attempts were made to investigate the influence of Pulse frequency and Duty factor of pulsed power in a high Pulse frequency regime on the surface characteristics of the hardened layer. The hardened layer (S-phase) was formed on all of the treated surfaces. Surface hardness reached up to 1300 $HV_{0.1}$ which is about 4.6 times higher than that of the untreated material (280 $HV_{0.1}$). The thickness of the hardened layer tends to increase lightly with the higher Pulse frequency and the higher Duty factor. The corrosion resistance of nitrocarburized duplex stainless steel was almost similar to that of the untreated material. Both the Pulse frequency and the Duty factor do not have a significant influence on the corrosion property of plasma treated duplex stainless steel.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.16-33
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• 2019

In this paper, a full-duplex NOMA relaying based underlay device-to-device (D2D) communication scheme is proposed, in which D2D transmitter assists cellular downlink transmission as a full-duplex relay. Specifically, D2D transmitter receives signals from base station and transmits the superposition signals to D2D receiver and cellular user in NOMA scheme simultaneously. Furthermore, we investigate the power allocation under the proposed scheme, aiming to maximize D2D link's achievable transmit rate under cellular link's transmit rate constraint and total power constraint. To tackle the power allocation problem, we first propose a power allocation method based on linear fractional programming. In addition, we derive closed-form expressions of the optimal transmit power for base station and D2D transmitter. Simulation results show that the performance of two solutions matches well and the proposed full-duplex NOMA relaying based underlay D2D communication scheme outperforms existing full-duplex relaying based D2D communication scheme.

• Corrosion Science and Technology
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• 제21권4호
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• pp.273-281
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• 2022

The effect of addition of Cu on the localized corrosion performance of aged duplex stainless steel in chloride media has yet to be explained in a consistent manner, and there is some controversy in the literature regarding the composition of stainless steel and the experimental conditions (pH, temperature, chloride concentration, etc.) used. In this work, the effect of the addition of Cu on the microstructure, hardness, and corrosion resistance of duplex stainless steel in an acidic chloride or high concentration sulfuric acid solutions was investigated for annealed and aged alloys. The Cu addition of annealed duplex stainless steel strengthened the alloy and reduced the ferrite contents of the alloy, and it also increased the polarization behavior in chloride or sulfuric solutions, except for the case of a high potential in acidic chloride solution. However, the Cu addition of aged duplex stainless steel reduced the formation of harmful phases such as sigma and kai and increased the polarization behavior in acidic chloride or sulfuric solutions up to 0.8 wt% of the Cu content, after which it slightly decreased at 0.8 wt% Cu or more.

• Journal of Animal Science and Technology
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• 제49권1호
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• pp.1-8
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• 2007

두 가지 primer 쌍을 동시에 이용한 duplex PCR 기법으로 붉은사슴과 엘크의 유전자 성 판별에 대한 이용가능성을 확인하기 위해 본 연구를 수행하였다. 근본적으로 포유동물의 성 분화는 Y-염색체 상에 암호화되어 있으며 웅성발생에 지배적인 역할을 수행하는 SRY 유전자의 존재 여부에 따라 결정되게 된다. X-, Y- 염색체에 상동인 유전자들 중 하나인 ZFX-ZFY 유전자는 X-, Y- 염색체 상에서 각각 발견된다. 유전자 성 판별에 앞서 붉은사슴의 ZFX-ZFY 유전자의 인트론 9를 포함하는 절편에 대한 염기서열의 특성을 확인하였다. 인트론 9의 길이는 ZFX와 ZFY에서 각각 529, 665-bp로 확인되었다. ZFY 인트론 9에서 전위인자의 일종인 bovine SINE element와 유사한 서열이 관찰되었다. SRY와 ZFX-ZFY 유전자들을 동시에 증폭하는 duplex PCR을 통해 유전자 성 판별을 수행하였고, 암수가 서로 구분되는 증폭 양상을 나타내었다: 암컷에서는 ZFX에서 증폭된 공통의 증폭 산물 하나만이 관찰되었고 수컷은 세 개의 밴드가 관찰되었다(ZFX에 해당하는 공통의 밴드와 ZFY와 SRY에서 증폭된 두 개의 수컷 특이 밴드). 두 가지 유전자에 대한 독립적인 PCR 시험에서 얻은 결과는 duplex PCR에 의해 얻은 결과와 동일한 양상을 나타내었다. 또한 유전자 성 판별의 결과들은 각각의 개체에 대한 표현형적 성판별 자료와 정확히 일치하였다. Y 염색체 특이적인 SRY와 X-, Y- 상동이면서 성적 이형성을 나타내는 ZFX-ZFY 유전자들에 대한 duplex PCR 방법은 붉은사슴과 엘크의 성 판별에 있어 여타 다른 대조시험을 요구하지 않으면서 없이 신속하고 정확한 정보를 제공하는 분석법이 될 것으로 기대된다.

• 한국정보통신학회논문지
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• 제13권4호
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• pp.629-635
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• 2009

본 논문에서는 하나의 국부 발진기를 갖는 FSK 이중통신 방식의 원격제어 무선 전송부를 설계 제작한다. 전 이중 방식의 FSK 양방향 동시통신 회로에서는 양방향 동시 통신을 위한 송수신 주파수를 설정하고, 반 이중방식에서는 송수신 신호를 발생하는 절체형 발진기 회로를 설계한다. 양 FSK 이중통신 방식의 원격제어 무선 전송부는 채널주파수간 간섭을 배제하기 위한 채널 사용 검지 및 자동 채널 설정 회로를 설계 구현하였으며, 400MHz 대역에서 50kHz 채널 간격을 갖는 위상동기 회로 구성의 Colpitz 형 국부발진주파수 회로와 10mW 이내의 소형 소출력 특성을 갖는다. 전 이중 방식의 송수신 주파수는 21.4MHz IF주파수의 2배 주파수인 42.8MHz주파수 간격으로 설계 구현하였다.

• 열처리공학회지
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• 제26권1호
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• pp.14-20
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• 2013

Duplex stainless steel, which is a kind of stainless steel with a mixed microstructure of about equal proportions of austenite and ferrite, is generally known as a unique material with excellent corrosion resistance and high strength. However, toughness, strength, and corrosion resistance of the steel could be reduced due to precipitation of topologically closed packed phases such as sigma phase during cooling. In case of large forged products, they have strong possibility that ${\sigma}$-phase precipitates due to difference of cooling rate between surface and inner of the products. Investigation on sigma phase precipitation behavior of duplex stainless steel with change of cooling rate was carried out in this study. Forged SAF 2205 duplex stainless steel was used as specimens to examine the cooling rate effect. Dissolution behavior of sigma phase was also discussed through resolution test of duplex stainless steel containing lots of sigma phase. Experimental results revealed that impact energy was very sensitive to precipitation of small amount sigma phase. However, sigma phase could be removed by short term resolution treatment and impact resistance of the duplex stainless steel was restored.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1398-1403
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• 2016

The simultaneous detection and accurate identification of hepatitis A virus (HAV) is critical in food safety and epidemiological studies to prevent the spread of HAV outbreaks. Towards this goal, a one-step duplex reverse-transcription (RT)-PCR method was developed targeting the VP1/P2B and VP3/VP1 regions of the HAV genome for the qualitative detection of HAV. An HAV RT-qPCR standard curve was produced for the quantification of HAV RNA. The detection limit of the duplex RT-PCR method was 2.8 × 10¹ copies of HAV. The PCR products enabled HAV genotyping analysis through DNA sequencing, which can be applied for epidemiological investigations. The ability of this duplex RT-PCR method to detect HAV was evaluated with HAV-spiked samples of fresh lettuce, frozen strawberries, and oysters. The limit of detection of the one-step duplex RT-PCR for each food model was 9.4 × 10² copies/20 g fresh lettuce, 9.7 × 10³ copies/20 g frozen strawberries, and 4.1 × 10³ copies/1.5 g oysters. Use of a one-step duplex RT-PCR method has advantages such as shorter time, decreased cost, and decreased labor owing to the single amplification reaction instead of four amplifications necessary for nested RT-PCR.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1994년도 특별강연 및 춘계학술발표 개요집
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• pp.126-128
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• 1994

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1994년도 특별강연 및 추계학술발표 개요집
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• pp.61-63
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• 1994

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1999년도 특별강연 및 춘계학술발표대회 개요집
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• pp.124-125
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• 1999