• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.609-614
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• 1998

고준위 방사성 폐기물 처분과 관련이 있는 가속기구동 소멸처리로는 미임계로이기 때문에 별도의 중성자원이 필요하다. 가속기에서 나오는 양성자를 받아 중성자를 발생시키는 중성자원으로 사용될 표적물로서 거론되는 방안중에 하나인 고체표적시스템에 대한 열전달 예비계산을 수행하였다. 고체표적물의 물질은 텅스텐을 대상으로 하였으며 표적시스템은 원통형구조를 가정하였다. 양성자 조사에 의한 텅스텐 물질의 핵파쇄반응으로 인한 내부발열을 모사하여 표적물내에서의 온도상승속도와 온도분포를 조사하였다. 계산결과 별도의 표적물에 대한 냉각시스템이 없는 상황에서 30∼37초만에 국부적으로 텅스텐의 온도가 녹는점 이상으로 상승하는 결과를 보였다. 따라서 고체표적물 시스템을 소멸처리로에서 사용하기 위해서는 표적물을 냉각시키기 위한 다각도의 방안이 모색되어야 한다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.61-62
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• 2016

우라늄전착물의 염 증류공정은 pyroprocess의 bottle neck에 해당되며, 회분식으로 조업된다. 본 발명에서는 증류탑 전단계에 고액분리실을 설치하고, 증류탑 후단에 냉각실을 설치하여, 전착물 도가니가 고액분리조- 증류조- 냉각조를 순차적으로 통과하여 조업시간을 크게 단축할 수 있도록 하였다. 또 도가니가 고온에서 이동할 수 있도록 중간에 고온 밸브를 설치하여 도가니가 다음 단계로 이동하면 새로운 전착물 도가니가 도입되어 연속적으로 조업이 가능하여 처리 용량이 향상되도록 하였다. 이에 따라 단위 시간당 처리용량을 현저히 높일 수 있다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.360-367
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• 1996

The OISF (Oxidation Induced Stacking Fault)is expected to affect the electrical properties in Si single crystals, and the nuclei of OISF are believed to be formed during the crystal growing process. Initial oxygen concentration, dopant type and its density, and cooling rate are regareded as major factors on OISF formation. In this study, the variations of OISF density under various cooling rate were investigated. Si single crystal was heated to $1400^{\circ}C$ in Ar ambient and cooled down to room temperature at different cooling rate, using horizontal tube furnace. After that, they were oxidized at $1150^{\circ}C$, and then, OISF was observed with optical microscope. The relation between oxide procipitates and OISF nucleation was investigated by FTIR analysis. As a result, it was found that there exists the intermediate cooling rate range in which OISF nucleation is highly enhanced. And also, it was found that OISF nucleation is closely related with silicon oxide procipitation in Si single crystals.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.41-47
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• 2012

Every object over $O^{\circ}K$ emits radiant energy based on its own temperature. Uncooled thermal imaging system displays the detected incident radiant energy as an image by signal processing. Recently, the uncooled thermal imaging system is applied to various areas such as medical, industrial, and military applications. Also, several researches are in progress to find new applications of the uncooled thermal imaging system. In this paper, we present effective method for controlling TEC-less detector in the uncooled thermal imaging system and also present the efficient control scheme for maximizing the accuracy of temperature measurement. The proposed scheme is to apply TEC-less and temperature detection algorithm in Uncooled thermal imaging system. In results of tests performed by using the actual chamber, we acquired images of better quality than the former system and temperature measurement accuracy was improved to less than $1^{\circ}C$.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.27 no.1
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• pp.14-27
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• 1998

• Applied Biological Chemistry
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• v.40 no.3
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• pp.220-224
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• 1997

As corn starches with different amylose content were heated at different temperature $(100^{\circ}C,\;121^{\circ}C)$ with starch / water ratio (1:3.5, 1:9) and heating-cooling treatment was repeated up to 4 times, the yield of RS(resistant starch) from heated corn starches was investigated by the enzymatic-gravimetric method and the ${\alpha}-amylase$ treatment. Compared to ${\alpha}-amylase$ method, enzymatic-gravimetric method was more effective to hydrolyze the amorphous region of heated corn starch. With increasing the amylose content and the number of heating-cooling treatment, the yield of RS increased, regardless of isolation method. Heated corn starches formed at $121^{\circ}C$ provided higher yield of RS than those formed at $100^{\circ}C$. Higher RS yield was also observed in the case of starch/water ratio (1:3.5) compared to the case of ratio (1:9).

• Food Science and Preservation
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• v.11 no.2
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• pp.250-256
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• 2004

The objectives of this study were to develop a new commercial grain cooler suited to domestic weather and post-harvesting conditions for paddy, and to evaluate the performance. A prototype grain cooler capable of cooling paddy of 200 tons within 24 hours was developed. The grain cooler was designed to control the refrigeration capacity from 0 to 100% by controlling the capacity of compressor with unloading solenoid valve and by changing the flow rates of hot refrigerant gas flowing into reheater and evaporator from compressor. And a controller with one chip microprocessor was developed to control temperature and relative humidity of cooling air. The maximum cooling capacity of the grain cooler was 35,284㎉/hr at condensing/evaporating pressure of 16.5/3.6 kgf/$\textrm{cm}^2$. Maximum flow rate of cooling air was 120 ㎥/min at static pressure of 279 mmAq. The total maximum required power was 22.8㎾, and total required energy was saved from 26.7 to 33.3% of maximum power depending on operating conditions. The coefficient of performance of refrigeration devices and total coefficient of performance of the grain cooler were 4.71 and 1.8, respectively.

• Korean Chemical Engineering Research
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• v.62 no.2
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• pp.163-172
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• 2024

In this study, two different scenarios for ammonia liquefaction in the green ammonia manufacturing process were proposed, and the economic-feasibility and environmental impact of each scenario were analyzed. The two liquefaction processes involved gas-liquid separation before cooling at high pressure (high pressure cooling process) or after decompression without the gas-liquid separation (low pressure cooling process). The high-pressure cooling process requires higher capital costs due to the required installation of separation units and heat exchangers, but it offers relatively lower total utility costs of 91.03 $/hr and a reduced duty of 2.81 Gcal/hr. In contrast, although the low-pressure cooling process is simpler and cost-effective, it may encounter operational instability due to rapid pressure drops in the system. Environmental impact assessment revealed that the high-pressure cooling process is more environmentally friendly than the low-pressure cooling process, with an emission factor of 0.83 tCO₂eq less than the low-pressure cooling process, calculated based on power usage. Consequently, the outcomes of this study provide relevant scenario and a database for green ammonia synthesis process adaptable to various process conditions.

• Bulletin of Food Technology
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• v.15 no.2
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• pp.107-111
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• 2002

초고압 가공처리는 별동의 화학 보존제를 사용하지 않고도 저온에서 식품유래 미생물을 사멸시킬 수 있기 때문에 식품분야에서 주목받는 새로운 가공기술이다. 이러한 초고압 처리의 장점 덕분에 관능적 특성이 우수하고 영양성분이 그대로 보존되는 고품질 식품의 제조도 가능하다. 고압 조건에서의 미생물 사멸정도를 측정하기 위해서는 흔히 실험실 규모의 장비(그림 1)을 사용하여 소량의 미생물 접종액을 처리함으로서 대량 처리시(그림 2)의 양상을 예측할 수 있다. 초기에 개발된 실험실 귬의 초고압 처리장비에는 일반적으로 고압용기 내부에 온도감지 장치가 부착되어 있지 않아, 압력 조건 하에서의 압축발열 및 순간 감압냉각 효과가 제대로 보고되지 않았다. 그러나 가열효과를 고려하지 않으면 초고압 처리기 특유의 가압 특성 대문에 실험 결과의 재현성을 얻기가 힘들고, 특히 대용량 생산설비의 경우 더욱 그러하다. 이론적으로 초고압 처리는 매우 예측 가능한 공정이다. 즉 고압요기 내부에서는 어느 지점이던 간에 압력이 고르게 분포되고, 가열 확산에 근거한 처리공정과는 달리 압력이 모든 지점에 순간적으로 공정상 불균일이 야기될 소지가 있는 부분은 오직 압축에 다른 발열과 열 전달에 의한 온도 편차에 기인한다. 실제로 처리 대상 제품과 압력 전달매체의 압축시 발열정도 차이와 시료, 매체, 고압용기 간의 열 손실 또는 열 흡수 대문에 고압처리 공정에서 온도가 일정하지 않을 수 있다.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1048-1054
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• 2011

Laser surface hardening process is the method of hardening surface by inducing rapid self quenching of laser injected area through transfer of surface heat to inside after rapid heating of laser injected area only by high density energy heat source. This surface treatment method does not involve virtually any thermal deformation by heat treatment nor accompanies any other process after surface hardening treatment. In addition, allowing local machining, this method is a surface treatment method suitable for die with complicated shape. In this study, die material cast iron was surface-treated by using high power diode laser with beam profile suitable for heat treatment. Since the shapes of die differ by press die process, specimens were heat-treated separately on plane and corner depending on the applied parts. At this time, corner heat treatment was done with optic head inclined at $10^{\circ}$. As a result, corner heat treatment easily involves concentration of heat input due to limitation of heat transfer route by the shapes compared with plane part, so the treatment accomplished hardening at faster conveying speed than plane heat treatment.