• Journal of Applied Biological Chemistry
• /
• 제60권2호
• /
• pp.113-117
• /
• 2017

생물학적정화는 미생물을 이용하여 중금속을 포함한 오염물질을 정화하는 방법이다. 효모는 다양한 중금속을 흡착하여 정화하는 능력이 우수하다고 잘 알려졌다. 따라서 본 연구는 여러 중금속 중 하나인 아연에 저항성인 큰 효모를 인위적인 돌연변이를 통해서 얻는 것에 초점을 두었다. 대조구인 효모를 1 mM 농도의 아연이 포함된 배지에서 키운 후 점차 아연의 농도를 높여 최종적으로 80 mM이 되는 지점까지 키웠으며 이 농도는 효모가 점진적 적응을 거쳤어도 성장이 불가능한 한계점 근처이며 이렇게 유도 분리된 효모를 ZnR이라 명명하였다. ZnR은 대조구 효모보다 아연에 대한 저항성이 현저히 증가되었으며 이 외에 카드뮴과 니켈에 대한 저항성도 증가되었지만 구리에 대한 저항성은 오히려 감소 되었다. ZnR이 보여준 아연에 대한 저항성 증가는 유전자 돌연변이에 의한 영구적인 획득 결과이다. 단 기간 내에 아연에 대한 저항성 큰 효모의 인위적인 유도 및 분리는 생물학적정화 연구에 유용하게 쓰여질 정보이다.

• Nuclear Engineering and Technology
• /
• 제39권3호
• /
• pp.231-236
• /
• 2007

Due to the occasional occurrences of stress corrosion cracking(SCC) in steam generator tubing(Alloy 600), degraded tubes are removed from service by plugging or are repaired for re-use. Since electrodeposition inside a tube does not entail parent tube deformation, residual stress in the tube can be minimized. In this work, tube restoration via electrodeposition inside a steam generator tubing was performed after developing the following: an anode probe to be installed inside a tube, a degreasing condition to remove dirt and grease, an activation condition for surface oxide elimination, a tightly adhered strike layer forming condition between the electro forming layer and the Alloy 600 tube, and the condition for an electroforming layer. The reliability of the electrodeposited material, with a variation of material properties, was evaluated as a function of the electrodeposit position in the vertical direction of a tube using the developed anode. It has been noted that the variation of the material properties along the electrodeposit length was acceptable in a process margin. To improve the reliability of a material property, the causes of the variation occurrence were presumed, and an attempt to minimize the variation has been made. A Ni alloy electrodeposition process is suggested as a primary water stress corrosion cracking(PWSCC) mitigation method for various components, including steam generator tubes. The Ni alloy electrodeposit formed inside a tube by using the installed assembly shows proper material properties as well as an excellent SCC resistance.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2001년도 추계학술발표논문집
• /
• pp.168-182
• /
• 2001

A new concept of stock preparation for the increase of bending stiffness in paper and board was proposed. The 'stiff' fibers, which were mechanically not treated or treated slightly to remove fiber curls, were combined with extensively refined fibers (ERF) to produce higher stiffness papers than those where the whole fibers were refined. The combination of 'stiff' fibers and extensively refined fibers produced higher stiffness at the same tensile strength than the control furnish, in which all the fibers are refined together. In this concept, the fibers from recycled papers could be as much useful as the virgin fibers as long as they are stiff enough or they can produce highly bondable fiber fractions by extensive refining. Use of the concept in real paper mill needs considerations such as increase of refining energy, slower drainage, and added drying burden, but savings of wood fibers, utilization of more recycled fibers, and increase of physical properties may offset the negative concerns. The success of this concept implementation in mills, therefore, depends on the wood fiber market around the mills and the proper decision making for the papermakers about how to apply this concept.

• 한국농공학회논문집
• /
• 제53권6호
• /
• pp.153-163
• /
• 2011

This research describe improved algorithm that is able to decide terminal criterion of Evolutionary Structural Optimization (ESO), reducing load of calculation to search load path of concrete beam, and apply to agricultural facilities. The ESO method is that make to discrete structure, structural analyze each element stress through FEM. And repeat generation with next material condition to become for most suitable composing. Individual element introduces concept of zero stiffness, but zero stiffness decisions are gone to direction of exclusion. In this stduy, improve algorithm to be convergence by 'Rule of Alive or Die' in arrival because is most suitable. Also, existing terminal criterion lack consistency because that used depend on experience of researcher. This research procedure is fellowed. First, all modulus of elasticity assume a half of elasticity modulus of material, Second, structural analysis by FEM, Third, apply to the remove ratio and restoration ratio for the 'rule of alive or die'. Forth, reconstruct the element and material conditions. And repeat the first to forth process. The terminal time of evolutional procedure is the all elastic modulus of element changed to blank value or elasticity modulus value of original. Therefore, in this study, consist the algorithm for programming, and apply to the agricultural facilities with concrete.

• 수산해양기술연구
• /
• 제51권4호
• /
• pp.576-582
• /
• 2015

The efficiencies of thermal power system using fossil fuel depend on heat exchangers which extract energy from the exhaust gas before it is expelled to the atmosphere. To increase heat transfer efficiency it is very important to maintain the surface of heat exchanger as clean condition. The accepted skill of cleaning of fouled surface of heat exchanger is soot blowing. A high pressure jet of air is forced through the flat surface of plate to remove the deposit of fouling. There is, however, little knowledge of the fundamental principles of how the jet behave on the surface and how the jet actually removes the deposit. Therefore, the study focuses on the measuring of cleaning area and cleaning dwell time after accumulating the simulated deposit on the flat surface. The deposit test rig was built for the study and simulated deposit material is used after measuring the physical property of the each material by shearing stress test. Much data was obtained for the analysis by the parameters change such as the different jet speed, different inner pressure and variable distance of the jet from the test rig surface. The experimental data was compared with the theoretical equation and most of the data matches well except some extreme cases.

• 한국항행학회논문지
• /
• 제13권6호
• /
• pp.926-932
• /
• 2009

건강에 관한 헬스케어기구 중에서 전신아마기의 보급이 급속도로 증가되고 있다. 현대인의 스트레스를 해소하기 위해 사용하는 이러한 전신안마기 사용시 PPG를 이용하여 HRV 신호를 측정하여 스트레스의 이완 정도를 판단하는 것이 중요하다. 그런데 이 경우 안마기에 의해서 피실험자가 움직이는 상태에서 측정이 이루어지므로 HRV의 측정신호에 동잡음이 개입된다. 본 논문에서는 이러한 복합신호에서 신호처리에 의해서 동잡음을 효과적으로 제거하여 원하는 HRV를 측정하여 분석하는 방법을 제시한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 C
• /
• pp.2008-2010
• /
• 2002

Process conditions of a novel negative thick photoresist, JSR THB-$430N^{(R)}$, are established in this paper. Although SU-8 obtains uniform and high-aspect-ratio structures, it is hard to remove the SU-8 mold after electroplating. The JSR THB-$430N^{(R)}$ can be more easily removed than the SU-8 and has a low internal stress. Introducing two step strip processes using acetone and the jSR THB-$S1^{(R)}$, the JSR THB-$430N^{(R)}$ electroplating mold was removed completely and a JSR THB-$430N^{(R)}$ film stress is compressive less than 2 MPa. In this paper, we obatined $200{\mu}m$ thick PR structure and $100{\mu}m$ thick electroplated nickel structure using the JSR THB-$430N^{(R)}$ photoresist.

• Tribology and Lubricants
• /
• 제33권6호
• /
• pp.282-287
• /
• 2017

SU-8 is an epoxy-type photoresist widely used for the fabrication of high-aspect-ratio (HAR) micro-structures in micro-electro-mechanical systems (MEMS). To fabricate highly integrated structures, chemical mechanical polishing (CMP) has emerged as the preferred manufacturing process for planarizing the MEMS structure. In SU-8 CMP, an oxidizer decomposes organic impurities and particles in the CMP slurry remove the chemically reacted surface of SU-8. To fabricate HAR microstructures using the CMP process, the adhesion between SU-8 and substrate material is important to avoid the delamination of the SU-8 film caused by the mechanical-dominant material removal characteristic. In this study, the friction force during the CMP process is measured with a CMP monitoring system to detect the delamination phenomenon and investigate the delamination of the SU-8 film from the silicon substrate under various pressure conditions. The increase in applied pressure causes an increase in the frictional force and wafer-edge stress concentration. The frictional force measurement shows that the friction force changes according to the delamination phenomenon of the SU-8 film, and that it is possible to monitor the delamination phenomenon during the SU-8 CMP process. The delamination at a high applied pressure is explained by the effect of stress distribution and pad deformation. Consequently, it is necessary to control the pressure of polishing, which can avoid the delamination in SU-8 CMP.

• 한국전자통신학회논문지
• /
• 제15권2호
• /
• pp.335-342
• /
• 2020

ESS(초기고장배제)는 제품생산 간 유입되는 '잠재결함'을 제거하기 위한 중요한 생산 프로세스로서 최근에는 방위사업 분야에서도 제품에 대한 필수 품질요구조건으로서 QAR(품질보증요구서)에 포함되고 있으나, 무기체계의 분류 및 작성자에 따라 내용 및 작성양식이 상이하거나, 중요한 요소가 누락되는 사례가 빈번하게 식별되고 있다. 따라서 본 논문에서는 MIL-HDBK-344A 기반의 정량적인 ESS 요구사항 표준안을 제시하여 QAR의 일관성 및 완전성을 보장하고, 잠재결함 제거 효과 파악을 위한 지표인 결함유도효율(PE) 산출 시 용이성을 확보하고자 한다.

• 펄프종이기술
• /
• 제34권5호
• /
• pp.63-69
• /
• 2002

A new concept of stock preparation for the increase of bending stiffness in paper and board was proposed. The "stiff" fibers, which were mechanically not treated or treated slightly to remove fiber curls, were combined with extensively refined fibers (ERF) to produce higher stiffness papers than those where the whole fibers were refined. The combination of "stiff" fibers and extensively refined fibers produced higher stiffness at the same tensile strength than the control furnish, in which all the fibers are refined together. In this concept, the fibers from recycled papers could be as much useful as the virgin fibers as long as they are stiff enough or they can produce highly bondable fiber fractions by extensive refining. Use of the concept in real paper mill needs considerations such as increase of refining energy, slower drainage, and added drying burden, but savings of wood fibers, utilization of more recycled fibers, and increase of physical properties may offset the negative concerns. The success of this concept implementation in mills, therefore, depends on the wood fiber market around the mills and the proper decision making for the papermakers about how to apply this concept. apply this concept.