• 한국응용곤충학회지
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• 제29권4호
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• pp.277-285
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• 1990

담배나방 (Heliothis assulta Guenee)의 용휴면에 대한 유기와 종료요인 및 휴면 지속기간 등에 대하여 실험실과 야외개체에 대하여 실험하였다. 일장과 온도조건이 용휴면유기에 밀접한 관련을 맺으며 $20^{\circ}C$와 lOL/140의 팡주기하에서 유충율 키웠을 때 100%의 휴면율을 얻을 수 있었다. 그러나 $25^{\circ}C$의 경우에는 본 실험에서 시도한 가장 짧은 광주기인 8시간하에서도 약 85%의 휴면율만 나타내었다. 결국 휴면을 유기하는 임계일장이 $25^{\circ}C$에서는 12-12.5시간, $20^{\circ}C$에서는 14-14.5시간으로 계산되었으며 휴면유기 조건에 감응하는 발육단계는 4령과 5령유충기였다. 수원 및 우리나라 중부지역에서 9월 20일경부터 채집되는 노숙유충은 모두 휴면으로 들어갔다. 그러나 성충, 알, 용 등은 실험실내 휴면유기 조건 ($20^{\circ}C$, lOL/140)에 처리해도 아무런 반응이 없었다. 휴면기간은 휴면유기온도가 낮으면 길어지는 경향이었으며 광주기와는 무관한 것으로 나타났다. 휴면용들은 저온처리를 받지않아도 깨어나지만 저온처리 기간이 길어질수록 휴면기간은 짧아졌다.

• 산업기술연구
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• 제24권A호
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• pp.227-238
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• 2004

This paper is results of experimental and nunerical works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand. Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Numerical analysis with the commercially available program of FLAC were performed to compare with results of centrifuge model experiment In numerical modelling. Mohr-Coulomb elasto-plastic constitutive model was used to simulaye the behavoor of Jumunjin Standard Sand and the interface element between the lining and the covered material was implemented to simulate the interaction between them. Compared results between model tests and numerical estimation with respect to displacement of the lining showed in good agreements.

• 한국환경과학회지
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• 제18권2호
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• pp.205-213
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• 2009

A laboratory experiment was conducted to investigate nitrogen removal from plating wastewater by a soil reactor. A combination of soil, waste oyster shell and activated sludge were used as a loading media in a soil reactor. The addition of 20% waste oyster shell and activated sludge to the soil accelerated nitrification (88.6% ${NH_4}^{+}-N$ removal efficiency) and denitrification (84.3% ${NO_3}^{-}-N$ removal) in the soil reactor, respectively. In continuous removal, the influent ${NH_4}^{+}-N$ was mostly converted to nitrate nitrogen in the nitrification soil reactor and only a small amount of ${NH_4}^{+}-N$ was found in the effluent. When methanol was added as a carbon source to the denitrification soil reactor, the average removal efficiency of ${NO_3}^{-}-N$ significantly increased. The ${NO_3}^{-}-N$ removal by methanol addition in the denitrification soil reactor was mainly due to denitrification. The phosphorus was removed by the waste oyster shell media in the nitrification soil reactor. Moreover, the phosphorus removal in the denitrification soil reactor was achieved by synthesis of bacteria and the denitrification under anaerobic conditions. The approximate number of nitrifiers and denitrifiers was $3.3{\times}10^5\;MPN/g$ soil at a depth of $1{\sim}10\;cm$ and $3.3{\times}10^6\;MPN/g$ soil at a depth of $10{\sim}20\;cm$, respectively, in the soil reactor mixed with a waste oyster shell media and activated sludge.

• 한국식품영양과학회지
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• 제21권3호
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• pp.247-254
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• 1992

1주령 병아리에 무콜린 식이를 급여하거나 무콜린 식이에 butanolamine을 첨가 급여하여 콜린 결핍을 심화시켜, 콜린 결핍이 지질대사에 미치는 영향을 알아보았다. 그 결과 콜린 결핍은 간장중량, 혈장 지질 및 지단백 수준에 유의적인 영향을 나타내지 않았다. 또한 간세포의 소포체에서 $^{14}$ C-oleic acid의 지질 혼입율에도 유의적인 영향을 끼치지 않았다. 한편 estrogen을 투여하여 고지혈증을 야기 시킨 경우 콜린 결핍군의 VLDL상승 정도가 낮은 경향을 나타내었고 비간장 무게와 간장의 지질함량은 증가하는 경향을 나타내었다. 한편 콜린 결핍은 병아리의 성장을 저해하였다 성장에 필요한 콜린을 충분히 합성하지 못하는 어린 병아리에 콜린 결핍을 야기 시켜 얻어진 이러한 결과는 간세포에서의 VLDL방출에 콜린이 크게 작용하지 않음을 시사하여 주었다. 그러나 고지혈증이 유발된 상황에서 극심한 콜린 결핍은 VIDL방출에 약간의 영향을 끼칠 수도 있음을 나타내었다.

• 농업과학연구
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• 제11권1호
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• pp.34-44
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• 1984

대두(大豆)요구르트 제품의 품질을 향상시키고 소화율이 증진된 제품을 개발하기 위한 기초자료를 얻기 위하여 대두(大豆), 탈지대두(脫脂大豆) 및 발아대두(發芽大豆)를 원료로 대두(大豆)요구르트를 제조하였다. 이때 제조과정중의 각종성분, 생균수 및 당류의 변화를 측정하고, 기호성을 조사하여 다음과 같은 결과를 얻었다. 1. Lactobacillus acidophilus의 초기산생성은 탈지두유에서 가장 높았고, 균의 생육은 발아두유에서 가장 왕성하였다. 2. 두유에 2% glucose를 첨가하면 산생성은 촉진되었다. 3. 대두유 및 탈지두유에 환원탈지유(還元脫脂乳)의 첨가로 산생성은 촉진되었으나, 발아두유에 있어서는 첨가효과가 인정되지 않았다. 4. 대두를 발아처리하면 raffinose와 stachyose의 함량은 감소되었고 glucose는 증가하였다. 5. 두유를 젖산발효시키면 raffinose나 stachyose의 함량은 감소되었다. 6. 관능검사(官能儉査)결과 발아두유에 10%의 환원세지유(還元稅脂乳)를 첨가하여 조제한 발아대두요구르트가 풍미면에서 가장 양호하였다.

• 설비공학논문집
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• 제25권7호
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• pp.377-385
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• 2013

In this study, the performance of an impeller according to blade length and pitch angle was studied experimentally by building a variable pitch impeller while changing blade length to review the effect of blade length and pitch angle on a fan's performance. The pitch angle was changed in six steps from $20^{\circ}{\sim}45^{\circ}$ at intervals of $5^{\circ}$ while the blade lengths were changed to 90 mm, 100 mm, 110 mm and 120 mm with an identical airfoil shape while carrying out the experiment. The results are summarized as follows : The air flow per static pressure of axial fans increased linearly with increase of pitch angle, but the high static pressure showed a decrease at a pitch angle of $35^{\circ}$. The shaft power increased proportionally to the pitch angle at all blade lengths; the larger the pitch angle, the larger the measured increase of shaft power. This is because the drag at the fan's front increases with the pitch angle. In the axial fans considered in this research, the flow and incre.

• 한국작물학회지
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• 제32권1호
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• pp.61-66
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• 1987

삼투처리와 무처리의 대두종자(품종 :Williams)에 대하여 두가지 온도(15, 3$0^{\circ}C$)에서 두가지의 종자수분함량(30%, 50%)으로 조절된 조건으로 0. 2, 4 및 8일간 전처리함에 있어서 시간별 세세구배치법 4반복으로 배치하여 발아와 묘신장을 조사하였던 바 주요결과는 다음과 같다. 1. 콩의 묘신장은 30에서 2일간 전처리함으로서 촉진되었으나 같은 온도에서 전처리기간이 길수록 억제되었다. 2. 삼투처리후 전처리된 종자는 수분흡수와 묘신장이 떨어졌다. 3. 종자수분함량이 50%로 조절된 뒤 전처리된 것은 체의 수분함량을 증가시켰으며 4일간까지의 전처리는 묘신장을 크게 하였다. 4. 묘의 건물중에서는 전처리온도가 3$0^{\circ}C$ 일때와 종자수분함량이 50%로 조절되어 8일간 전처리하였을 때 감소되었다.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1114-1123
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• 2015

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oil-paper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ. Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

• 대한토목학회논문집
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• 제33권3호
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• pp.855-864
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• 2013

지진격리장치로서 천연고무받침의 동적 특성은 주재료인 고무의 동적거동과 비선형 성질에 의존하고 있다. 역학적이나 환경적인 영향으로 인해 고무재료에 노화가 진행되고 결국에는 손상이 불가피하게 발생하게 된다. 고무재료의 노화에 주원인은 높은 온도에서 반응열로 인한 산화반응으로 알려져다. 이에 따라 천연고무받침에 대한 가속 열 노화실험을 수행하여 열 노화 전 후에 대해 받침의 특성값을 상호 비교하였다. 실험 결과 열 노화 현상은 전단강성과 에너지 감쇠 그리고 등가감소계수에 영향이 있음을 알 수 있었다. 또한 열 노화에 의한 동적특성의 저하를 실제 교량에 적용하여 천연고무받침의 열 노화가 교량의 내진성능에 미치는 영향을 수치해석을 통해 비교분석하였다. 그 결과 천연고무받침에 대하여 열 노화에 따른 기본 특성변화가 교량의 내진성능에 미치는 영향은 크지 않음을 알 수 있었다.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2183-2190
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• 2000

A thermal aging is observed in a primary reactor cooling system(RCS) made of a casting stainless steel when the RCS is exposed for long period at the reactor operating temperature, 290~3300C An investigation of effects of thermal aging on a low cycle fatigue characteristics included a stress variations caused by a reactor operation and trip, is required. The purpose of the present investigation is to find an effect of a thermal aging of the CF8M on a low cycle fatigue life. The specimen of CF8M are prepared by an artificially accelerated aging technique holding 300 and 1800hr at 4300C respectively. The low cycle fatigue tests for the virgin and two aged specimens are performed at the room temperature for various strain amplitudes($\varepsilon$ta), 0.3, 0.5, 0.8, 1.0, 1.2 and 1.5% strain. Through the experiment, it is found that the fatigue life is rapidly reduced with an creasing of the aging time. The experimental fatigue life estimation formulas between the virgin and two aged specimen are obtained and are proposed to a analysis purpose.