• 대한기계학회논문집
• /
• 제19권10호
• /
• pp.2678-2689
• /
• 1995

In this study, a new hot-wire anemometer which has greater sensitivity than that of a constant temperature anemometer (CTA) was proposed. In contrast to CTA, the wire working resistance of the new anemometer increases with flow velocity, that is, the operating mode of the wire becomes variable temperature. The variable temperature anemometer(VTA) was made by substituting a voltage controlled variable resistor such as photoconductive cell or transistor for one of the resistors in the bridge. By positively feeding back the bridge top signal to the input side of these electronic components, the wire overheat ratio could be increased with velocity automatically. Static response analyses of the VTA, constant voltage anemometer (CVA) and CTA were made in detail and calibration experiments were performed to validate the proposed operating principle. The wire operating resistance of the CVA decreases with velocity and this leads to lower sensitivity than that of a CTA. But the sensitivity of the newly proposed VTA is superior to that of a CTA, since the wire overheat ratio increases with velocity. Consequently, it is found that the major factor that is responsible for large sensitivity of a VTA is not the working resistance itself but the change of the wire working resistance with velocity.

• Current Photovoltaic Research
• /
• 제5권3호
• /
• pp.83-88
• /
• 2017

The growth of intermetallic compounds is an important factor in the reliability of solar cells. Especially, the temperature change in the soldering process greatly affects the thickness of the intermetallic compound layer. In this study, we investigated the intermetallic compound growth by Sn-diffusion in solder joints of solar cells. The thickness of the intermetallic compound layer was analyzed by IR lamp power and hot plate temperature control, and the correlation between the intermetallic compound layer and the adhesive strength was confirmed by a $90^{\circ}$ peel test. In order to investigate the growth of the intermetallic compound layer during isothermal aging, the growth of the intermetallic compound layer was analyzed at $85^{\circ}C$ and 85% for 500 h. In addition, the activation energy of Sn was calculated. The diffusion coefficient of the intermetallic compound layer was simulated and compared with experimental results to predict the long-term reliability.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2003년도 가을 학술논문집
• /
• pp.105-108
• /
• 2003

방사성 물질 취급시설인 핫셀을 출입하거나 핫셀 내의 장비 반출 등으로 인하여 핫셀 뒤편에 위치한 서비스 구역은 오염이 발생할 수 있다. 오염이 발생된 서비스 구역을 법령이 정한 표면허용오염도 이하로 제염 관리하기 위해서는 많은 방사성폐기물이 발생할 뿐만 아니라 제염하기 위한 소요인력 및 시간 또한 많이 요구된다. 이러한 문제점을 해소하기 위한 습식 제염장치는 부착된 오염원을 바닥 면으로부터 분리시키는 브러시를 회전시키는 부분, 회전브러시에 제염액 또는 세제를 공급하는 부분, 바닥 면에서 분리된 오염원과 제염액 또는 세제를 흡입하는 부분 그리고 주행하는 부분으로 구성되며, 스테인리스 재질로 제작하여 내부식성 뿐만 아니라 장치 자체의 제염도 쉽게 제작하여 조사후시험시설의 서비스 구역에서 제염장치의 성능시험을 수행하였다.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2003년도 가을 학술논문집
• /
• pp.411-420
• /
• 2003

원자력발전소 운전과 함께 국내 원전에서 계속 발생, 저장하고 있는 사용후핵연료를 안전하고도 효율적으로 관리하기 위하여 차세대관리 종합공정을 개발하고 있으며, 이를 실증하기 위한 시설을 설계 중에 있다. 이 실증시설은 조사재시험시설에 마련된 예비 핫셀을 차세대관리 종합공정의 특성을 고려하여 개조하여 사용할 예정이다. 이 연구에서는 실증시설에 대한 기존 시설 및 부대시설의 개조방안 등 기본 건축구조 설계에 대한 기준과 설계내용을 제시하였으며, 건축구조물의 안전성을 입증하기 위한 해석을 수행하고 그 결과를 제시하였다. 본 연구결과는 차세대관리 종합공정 실증시선의 상세설계를 위한 자료로 사용될 것이며, 시설의 인허가를 위한 자료로 활용될 것이다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
• /
• pp.181-184
• /
• 2005

In this paper, we have improved a novel fast response time liquid crystal operating mode using tilt angle in the unique condition by hot-plate equipment. The new control of tilt angle for nematic liquid crystal (NLC) with negative and positive dielectric anisotropy on the rubbed homeotropic polyimide (PI) using baking method by Hot-plate equipment was investigated. LC tilt angle decreased with increasing baking temperature and time. Especially, the low LC tilt angle of positive type NLC (${\Delta}n$>0) on the rubbed homeotropic PI surface by increasing temperature and time was measured. The EO characteristics of the high tilted OCB(HTOCB) mode using control of tilt angle on the homeotropic surface than that of conventional OCB cell can be improved. We suggest that the developed the HTOCB cell using control of tilt angle on the homeotropic surface is a promising technique for the achievement of a fast response time and a high contrast ratio.

• Nuclear Engineering and Technology
• /
• 제50권3호
• /
• pp.504-511
• /
• 2018

In Lithuania, all spent nuclear fuel (SNF) resulted from the operation of the Ignalina Nuclear Power Plant (INPP), which had two Russian Acronym for "Channelized Large Power Reactor"-type reactors. After the final shutdown, the total amount of SNF at the INPP was approximately 22,000 fuel assemblies. All these assemblies will be stored for about 50 years and disposed of after that. The decision to shut down and decommission both reactors in Lithuania before termination of design period raises a significant challenge for the treatment of accumulated SNF. Therefore, various techniques and technologies for SNF management were developed and justified for that specific case, and a set of special equipment was installed at the INPP, the effectiveness of which was demonstrated during its operation. This article presents unique techniques related to the management of SNF adopted and commissioned at the INPP after its operation shutdown, namely fuel rod cladding leak tightness control system and special equipment for collection of possible spillage during handling of SNF assembly in the hot cell. The operational experience and measurement results of fuel rod cladding leak tightness control system are presented.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 추계학술대회 논문집
• /
• pp.1055-1058
• /
• 2005

In the ACPF(Advanced spent nuclear fuel Conditioning Process Facility), the spent fuel pellets which are highly radioactive materials are separated with its clad and are fed into the next conditioning process. For this, at the other facility called PIEF(Post Irradiation Examination Facility) a spent fuel rod, 3.5 m long, is cut by 25 cm long which is suitable length fur the decladding process. These rod-cuts are packed into the capsule and are moved to the ACPF. Once the capsule is unloaded in the ACPF, the rod-cut is taken out one-by-one from the capsule and installed on the decladding device. In these processes, the crushed spent fuel pellet can be scattered inside the facilities and thus it contaminate the hot cell. In this paper, we developed the specially designed capsule which prevents the pellets scattering and remarkably reduces the leading and unloading time of the rod-cuts.

• 한국기계가공학회지
• /
• 제20권11호
• /
• pp.100-107
• /
• 2021

The use of new and renewable energy is essential to solve the problem of increasing fossil fuel use due to industrial development. The paradigm of the automobile industry has changed due to the strengthening of environmental regulations in developed countries, and the development of eco-friendly cars is underway. Fuel cell electric vehicles (FCEVs), which use hydrogen as fuel, require strict standards for fuel-related components. In particular, check valves for FCEV control high-pressure hydrogen and thus, must be sufficiently strong for the challenging environment caused by high-pressure hydrogen. Therefore, this study used DEFORM 3D, a regular finite element analysis program, to check the moldability of check valves for FCEV, design the process, verify reliability through single streamline analysis, tensile tests, and ANSYS simulations, and identify suitable materials for the high-pressure hydrogen environment.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제47권2호
• /
• pp.140-146
• /
• 2023

In recent years, the number of patients with benign prostatic hyperplasia (BPH), a condition that commonly occurs in elderly men, has increased due to aging and the adoption of western dietary habits. Treatment with chemical drugs, such as finasteride or dutasteride, can cause side effects such as erectile dysfunction or sexual problems. This necessitates the development of remedies using natural substances derived from food ingredients. In this study, we investigated the inhibitory effects of Oxya chinensis sinuosa hot water extract (OCH) on BPH production in LNCaP cells, a hormone-dependent prostate cancer cell line. We found that the mRNA expression of androgen receptor (AR), prostate specific antigen (PSA), and, 5α-reductases 1, and 2 decreased following treatment with OCH. Furthermore, OCH treatment resulted in reduced protein expression of BPH regulators, such as AR. Collectively, these results suggest that OCH exerts a beneficial effect on BPH by inhibiting the AR signaling pathway, indicating the potential of OCH as a therapeutic agent for the prevention and treatment of BPH.

• 방사성폐기물학회지
• /
• 제3권2호
• /
• pp.149-157
• /
• 2005

원자력연구시설의 핫셀 내 바닥이나 장치표면에 부착된 고방사능분진의 제거를 위해서 PFC제염기술을 적용한다. 고가인 PFC 용액의 재사용을 위해서는 여과장치의 개발이 필요하고 제염종료 후 이차폐기물의 양을 최소화할 필요가 있다. PFC 제염폐액 내 방사성 입자를 제거하기 위해 핫셀 내의 고방사능분진의 오염 특성을 조사했다. 여과 막을 이용한 입자의 제거효율 측면에서 보면 세라믹 , PVDF, PP 막 모두가 95$\%$ 이상의 높은 여과 성능을 보였다. 기공 크기가 같은 동일 여과 막에서는 입자가 크거나 가하는 압력이 높을수록 좀더 높은 제거효율을 나타내었고, 3psi이하에서는 PVDF의 제거효율이 다른 막에 비해 작게 나타났다. 플럭스 성능은 PVDF 막이 가장 높은 수준을 나타냈고 세라믹과 PP 막에서는 다소 낮은 성능을 보였다. PVDF 막은 낮은 압력과 짧은 여과시간으로 최대(한계)플럭스에 도달함을 확인하였다. 세라믹 막은 모의입자의 제거 효율은 높지만 다소 낮은 Flux 성능을 나타냈다. 또한, 막 자체의 비싼 가격과 쉽게 부서지는 성질의 단점을 지니고 있지만 무기화합물의 재질로 되어있기 때문에 알파방사능 환경에서 H, 가스를 발생하는 고분자 막인 PVDF, PP 막과 비교하여 훨씬 안정적이었다. 그리고 이들 소수성 여과막들의 특성 비교를 바탕으로 세라믹 막을 적용한 PFC 실증 여과장치의 공정도를 살펴보았다.