• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1400-1404
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• 2005

This paper presents the temperature control of aluminum plate by using Peltier element. Peltier effect is heat pumping phenomena by electric energy as one of the thermoelectric effect. So if current is charged to Peltier element, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier element is used to control the temperature of small aluminum plate with current control and operating cooling fan only while cooling duration. Operating cooling fan only while cooling duration is proper to get more rapid heating and cooling duration. As a result of experiment, it takes about 100sec period to repeating temperature between $35^{\circ}C$ and $70^{\circ}C$ and about 80sec from $40^{\circ}C$ to $70^{\circ}C$ in ambient air temperature $25^{\circ}C$ and while operating cooling fan only in cooling duration. Future aim is to apply this temperature control method in actuating SMHA(special metal hydride actuator) which is applicable in Siver project acting in low frequency range by using Peltier element for heating and cooling.

• 한국농림기상학회지
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• 제14권3호
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• pp.119-123
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• 2012

이 연구는 월 기상자료를 이용하여 작물 생육에 중요한 겨울철 저온 발생일수를 효과적으로 추정하기 위해서 수행되었다. 전국 61개 기상관서의 1981~2010년의 30년 간의 일 최저기온자료를 확보하여 $-15^{\circ}C$부터 $5^{\circ}C$까지 각 온도 이하 일수와 월 최저기온의 평균들을 비교한 결과, 1월 최저기온의 평균을 이용하였을 때 저온 발생일수를 가장 적합하게 추정할 수 있었다. 1월 최저기온 평균자료로부터 기준온도 이하가 되는 저온 발생일수를 추정할 수 있는 2차 함수 형태의 간단한 추정식을 제시하였다. 여러 온도 범위에서 추정식을 활용하기 위하여 추정식의 계수를 저온을 평가하는 기준온도로부터 구할 수 있도록 두 개의 2차 함수식을 도출하였고, 이 식들은 결정계수가 0.995 이상이었다. 분석에 이용된 자료와 기간을 달리하여 1971~2000년 30년 일 기상자료를 이용하여 검증해본 결과 기준온도 $-10{\sim}0^{\circ}C$ 범위에서는 저온 발생일수를 비교적 정확하게 예측할 수 있었으나, $-15^{\circ}C$에서는 다소 과소하게 추정되는 결과를 보였다.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권1호
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• pp.27-32
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• 2004

With an objective of evolving quantitatively and qualitatively superior bivolitine silkworm hybrid of Bombyxmori L. for tropics with shorter larval duration without compromising on productivity traits, a breeding programme was initiated at this institute during 1997 by utilizing breeding resource material from the institutes Germplasm collection. The breed SD7 is characterized with plain larvae spinning white oval cocoons and SD12 is characterized by sex-limited larval markings spinning white dumb-bell cocoons. After fixation, these breeds along with other newly evolved breeds were subjected for hybrid evaluation in the laboratory. Based on the hybrid studies, the hybrid SD7${\times}$SD12 was selected and evaluated for one year comprising three major sea- sons (6 trials) of tropics viz., Pre-monsoon (characterized by high temperature, low humidity and without any rain fall), Monsoon (characterized by moderate temperature, heavy rain fall with high humidity) and post-monsoon season (characterized by low temperature and low humidity with frequent rain fall) to know the fluctuations in the larval duration. The evaluation studies indicated that the hybrid is having shorter larval duration with productive merits. The hybrid SD7${\times}$SD12 recorded survival percent of 92.74, shell weight of 46.7 cg, shell ratio % of 24.0 and filament length of 1,200 meters with a shorter larval duration of 24 hrs; when compared to productive hybrid CSR2${\times}$CSR5(control). The breeding methodologies and hybrids usefulness for tropics were discussed.

• Composites Research
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• 제30권1호
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• pp.7-14
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• 2017

In this paper, the inter-lamina shear strength (ILSS) of multi-wall carbon nanotube (MWNT) reinforced carbon fiber reinforced plastics (CFRP) and thin-ply composites were verified under low earth orbit (LEO) space environment. CFRP, MWNT reinforced CFRP, thin-ply CFRP and MWNT reinforced thin-ply CFRP were tested after aging by using accelerated ground simulation equipment. The used ground simulation equipment can simulate high vacuum ($2.5{\times}10^{-6}torr$), atomic oxygen (AO, $9.15{\times}10^{14}atoms/cm^2{\cdot}s$), ultraviolet light (UV, 200 nm wave length) and thermal cycling ($-70{\sim}100^{\circ}C$) simultaneously. The duration of aging experiment was twenty hours, which is an equivalent duration to that of STS-4 space shuttle condition. After the aging experiment, ILSS were measured at room temperature ($27^{\circ}C$), high temperature ($100^{\circ}C$) and low temperature ($-100^{\circ}C$) to verify the effect of operation temperature. The MWNT and thin-ply shows good improvement of ILSS at ground condition especially with the thin-ply. And after LEO exposure large degradation of ILSS was observed at MWNT added composite due to the thermal cycle. And the degradation rate was much higher under the high temperature condition. But, at the low temperature condition, the ILSS was largely recovered due to the matrix toughening effect.

• 대한기계학회논문집B
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• 제31권6호
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• pp.514-521
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• 2007

This study focused on the effects of the $CO_2$ gas concentration in fresh charge and induction air temperature on the combustion characteristics of homogeneous charge compression ignition with dimethyl ether (DME) fuel, which was injected at the intake port. Because of adding $CO_2$ in fresh charge, start of auto-ignition was retarded and bum duration became longer. Indicated combustion efficiency and exhaust gas emission were found to be worse due to the incomplete combustion. Partial burn was observed at the high concentration of $CO_2$ in fresh charge with low temperature of induction air. However, indicated thermal efficiency was improved due to increased expansion work by late ignition and prolonged bum duration. Start of auto-ignition timing was advanced with negligible change of burn duration, as induction air temperature increased. Burn duration was mainly affected by oxygen mole concentration in induction mixture. Bum duration was increased, as oxygen mole concentration was decreased.

• International Journal of Industrial Entomology and Biomaterials
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• 제11권2호
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• pp.139-143
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• 2005

The implications of temperature (25, 30 and $35^{\circ}C$) and relative humidity (RH; 60, 70 and $80\%$) on the hatching rhythmicity and hatching parameters (percentage and duration) were studied in the silkworm, Bombyx mori L. under natural photoperiod (LD 12 : 12). Disease free layings (DFLs) of two pure silkworm breeds, Pure Mysore (PM, a multivoltine breed) and $NB_4D_2$ (a bivoltine breed), and their hybrid, $PM{\times}NB_4D_2$ were introduced into the experimental conditions on the $3^{rd}$ day of oviposition till completion of hatching. The hatching rhythm was predominantly diurnal under all temperature and humidity conditions, with peaks just after 'lights-on' phase (6 hrs). Extreme temperature and humidity conditions did not alter the hatching rhythmicity, but prolonged the hatching durations, extending it to the next day, coupled with reduced hatching percentage in PM and $PM{\times}NB_4D_2{\cdot}In\;NB_4D_2$, on the other hand, hatching did not extend to the next day. Hatching percentage in this breed, however, reduced below the economic level under high temperature and low humidity conditions. The high temperature and low humidity together, though did not alter the rhythmicity, seems to exert synergetic effect on the hatching percentage and its duration in the silkworm, B. mori.

• 한국농림기상학회지
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• 제16권1호
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• pp.51-58
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• 2014

배의 휴면기간 중 저온 유지 시간 및 온도에 따른 내동성을 비교하고자 감천배, 만풍배, 신고, 원황, 추황배, 풍수, 한아름, 행수, 화산, 황금배 등의 1년생 가지를 각각 $-21^{\circ}C$, $-24^{\circ}C$, $-27^{\circ}C$, $-30^{\circ}C$, $-33^{\circ}C$의 온도로 6, 9, 12시간 동안 처리한 후 꽃눈 발아율, 전해질 누출률, TTC검정을 하였다. 저온처리 시간에 따른 꽃눈발아율은 $-21^{\circ}C$에서 6시간일 경우 품종간 거의 차이가 없었으나 온도가 낮아지고 지속시간이 길어질수록 낮아졌다. 전해질 누출률은 $-30^{\circ}C$ 이하에서는 저온지속시간에 관계없이 대부분의 품종이 30%이상의 높은 전해질 누출률을 보여 온도가 낮아질수록 저온지속 시간이 길수록 전해질 누출률이 높아졌다. 저온에서 높은 발아율을 보였던 만풍배, 신고, 추황배는 $-30^{\circ}C$ 9시간에서 각각 26.1%, 14.7%, 28.3%로 다른 품종보다 낮은 전해질 누출률을 보였다. TTC 검정을 통한 흡광률은 $-21^{\circ}C$에서 6시간일 경우 66.0~96.5%, 9시간에는 49.4~91.9%, 12시간에는 37.3~89.4%로 저온유지 시간이 길어질수록 흡광률이 낮아졌다. 배의 품종별 내동성 확인 결과 꽃눈발아율은 전해질누출률 또는 TTC 검정을 통한 흡광률과의 높은 상관관계를 보였으며 배의 외재휴면 기간 중 내동성은 저온 유지시간 및 온도에 따라 다르며 품종별 저온 피해 한계온도가 다름을 확인할 수 있었다.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.769-775
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• 2017

The corrosion behavior of stainless steel (304 and 316 type) and copper induced by LiCl-KCl at low temperatures in the presence of sufficient oxygen and moisture was investigated through a series of experiments (at $30^{\circ}C$, $40^{\circ}C$, $60^{\circ}C$, and $80^{\circ}C$ for 24 hours, 48 hours, 72 hours, and 96 hours). The specimens not coated on one side with an aqueous solution saturated with LiCl-KCl experienced no corrosion at any temperature, not even when the test duration exceeded 96 hours. Stainless steel exposed to LiCl-KCl experienced almost no corrosion below $40^{\circ}C$, but pitting corrosion was observed at temperatures above $60^{\circ}C$. As the duration of the experiment was increased, the rate of corrosion accelerated in proportion to the temperature. The 316 type stainless steel exhibited better corrosion resistance than did the 304 type. In the case of copper, the rate of corrosion accelerated in proportion to the duration and temperature but, unlike the case of stainless steel, the corrosion was more general. As a result, the extent of copper corrosion was about three times that of stainless steel.

• 농업과학연구
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• 제7권1호
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• pp.1-5
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• 1980

수도(水稻) 신품종(新品種)들의 내냉성(耐冷性) 판별(判別)과 냉해대책(冷害對策)을 위하여 생식생장기(生殖生長期)에 있어서 저온(低溫)의 정도(程度)와 기간(期間)이 임실(稔實)과 등숙(登熟)에 미치는 영향(影響)을 검토(檢討)하여 다음과 같은 결과(結果)를 얻었다. 1. 수도(水稻) 감수분열기(減數分裂期)에 있어서 저온(低溫)의 정도(程度)가 크고 기간(期間)이 길어 질수록 출수(出穗)가 지연(遲延)되고 불임(不稔)이 증가(增加)하였으며 저온(低溫)에 의(依)한 감수(減收)는 주(主)로 불임증가(不稔增加)에 기인(基因)하였으나 $15^{\circ}C$의 저온(低溫)에서는 출수(出穗) 지연(遲延)도 관여(關與)하는 것으로 보였다. 2. $15^{\circ}C$ 6일간(日間) 처리(處理)에서는 불임(不稔)과 발육정지립(發育停止粒)이 다 같이 증가(增加)하고 완전(完全) 발숙립(發熟粒)은 거의 없었다. 3. 신품종(新品種)들은 기존(旣存) 품종(品種)보다 생식생장기(生殖生長期) 냉해(冷害)가 현저(顯著)하였고 내냉성(耐冷性) 검정(檢定)의 parameter로서는 감수분열기(減數分裂期)의 $15^{\circ}C$ 4일간(日間) 처리(處理)가 적당(適當)한 것으로 보였다.

• 한국환경농학회지
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• 제14권2호
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• pp.155-162
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• 1995

계절별로 일조시간과 기온과의 관계를 밝히고 작물재배시 기후자원 활용의 효율을 기하고자 지역별 월별 기상자료를 분석한 결과는 다음과 같다. 1. 강릉지방의 여름이 기온은 높으나 일조시간은 겨울보다도 적은 특징을 나타내었다. 2. 순복사량과 일조시간은 정의 상관이 있으며, 7월에는 일조시간 증가에 따라 순복사량의 증가가 컸다. 3. 일조시간 증가에 따른 현열전달량의 증가는 4월과 10월에 컸고, 7월이 가장 낮았다. 4. 연중(年中) 고온다조지역은 여수, 대구, 포항 등지이고, 저온과조지역은 춘천, 서올, 울릉도 등지이다. 5. 일조시간은 봄과 가을에는 기온교차와 정의 상관관계가 있으며, 여름에는 최고기온과 그리고 겨울에는 최저기온과 부의 상관관계가 있었다. 6. 1월의 일조시간이 평년대비 1시간 길어짐에 따라 평균기온은 평년에 비해 $1{\sim}1.7^{\circ}C$ 정도 낮아졌다.