• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.160-165
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• 2004

At this research, we examined probability of light bulb's life span value and prediction on purpose to inquire out the span of repeat velocity as fracture probability by executing the fatigue test, which is considered property of Tungsten filament's thermal fatigue used as an automobile bulb. As a result we can confirm what the most suitable solution is weibull distribution and log normal distribution. Tungsten filament's span gets longer as the fatigue repeat velocity gets shorter And, repeat span is about 15%~40% shorter than sequence life span.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.519-524
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• 1999

A bulb-tee sectioned girder is proposed for long span bridge exceeding 40 meters. The proposed bulb-tee girder is developed by non-linear analysis process. This study investigates the structural behavior and efficiency of proposed bulb-tee sectioned girder using 1/2 scaled prototype beam specimen. Three specimens are tested under three point static loading system. The crack patterns, failure mode and ultimate load capacity of each specimen are reported in this paper and they are compared to each other.

• 전기학회논문지
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• 제56권7호
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• pp.1261-1267
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• 2007

Although LEDs have been used in various applications with improving the brightness and luminous efficacy, the electrical and optical characteristics of high power LED varies at different temperature and starting time. In this paper, optimal heat sink and apparatus design were conducted using IR camera and ICEPAK on the LED bulb consisting with fourteen LED array. The temperatures of heat sink and LED device of the designed LED bulb without cooling pan were $74^{\circ}C\;and\;96.8^{\circ}C$, respectively, showing in good themal characteristics. For high efficiency driving circuit of LED array adopted optimal heat sink design, driving circuits of constant voltage and current circuits were suggested and fabricated. As a result the efficacy of all driving circuits showed more than 20 lm/W. Also, the constant current circuits are suitable for signal lamp, hallway lamp, and flash lamp having short operating time(about 30 min). On the other hand, a reading light and indoor lamp having long operating time can be controlled by constant voltage circuit.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.418-425
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• 2009

A vertical bulb turbine unit with elbow type draft tube has been developed due to avoidance of complicated assembling and long standstill period at overhaul in comparison with conventional horizontal bulb turbine unit. Before designing the prototype vertical bulb unit, a hydrographic model test was carried out to establish the ideal design concept for this innovative generating unit. Froude similarity is not available for vortex occurrence. Consequently, an intake structure without air entraining vortices under all the flow conditions is developed, and it is confirmed that the surge wave at load rejection is not affected harmful influence for other constructions.

• 설비공학논문집
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• 제15권9호
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• pp.779-785
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• 2003

The present work proposed a newly developed fluidized bed-type psychrometer that could be applicable to the high temperature and contaminant gases. The psychrometer is a device that test gas passes through the water in a glass bottle as a bubbly flow to obtain the adiabatic saturation temperature. A fluidized bed-type psychrometer was made and its characteristics were compared with the Assmann Psychrometer. The characteristic time was in the order of a hundred seconds, and decreased for the decrease of the mass of water and the increase of the air flow rate. The air flow rate and the insulation of the glass bottle were definitely important in the accurate measurement of the wet bulb temperature. The error in wet bulb temperature became less than 5 percent of the difference of dry and wet bulb temperatures if the air velocity in the glass bottle was greater than 1.5m/s.

• 한국작물학회지
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• 제23권2호
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• pp.141-144
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• 1978

패모린경의 무게를 15gr, 3gr, 5gr, 7gr, 9gr의 5등급별로 나뉘어 파종하였을 때에 그에 따른 발아상태, 초장, 개화, 자구 및 수량에 대하여 조사하였다. 1. 인경의 무게가 1.5gr 및 3gr되는 것은 발아시, 발아기간이 5gr, 7gr, 및 9gr되는 것에 비하여 발아시가 늦고 발아기간이 긴 경향을 나타냈고, 초장도 3∼5분지 1밖에 되지 않었다. 2. 개화는 인경이 무겁고 영양상태가 양호한 7gr∼9gr 상태에서 50％∼75％ 였으나, 3gr이하의 것은 1％에 불과했다. 또한 자구는 5gr이상에서 현저한 증가를 보였다. 3. 수량을 증가시키기 위하여서는 5gr이상의 패모를 사용하여야 한다는 사실을 알게 되었다.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.140-149
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• 2011

For a certain operating point of a horizontal shaft bulb turbine (i.e. volume flow, net head, blade angle, guide vane angle) the efficiency for different pressure levels (i.e. different Thoma-coefficient ${\sigma}$) is calculated using a commercial Computational Fluid Dynamics (CFD-)-code including two-phase flow and a cavitation model. The results are compared with experimental results achieved at a closed loop test rig for model turbines. The comparison of the experimentally and numerically obtained efficiency and the visual impression of the cavitation show a good agreement. Especially the drop in efficiency is calculated with satisfying accuracy. This drop in efficiency in combination with the visual impression is of high practical importance since it contributes to determine the admissible cavitation in a bulb-turbine. It is seen that the incipient cavitation in Kaplan type turbines has no major importance in determing this admissible amount of cavitation.

• 태양에너지
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• 제19권1호
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• pp.59-65
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• 1999

The zone of greenhouse in Korea increase on a scale yearly. Particularly, greenhouse take up a important value on the agriculture economy. Greenhouse of scale, material, heating system, and drain is progressing to industrialization. The dry bulb temperature, humidity, photosynthesis and so forth are necessary to maintain environment control of greenhouse. The dry bulb temperature among them greatly affects growing of a plant. The purpose of this study is to analyzed the indoor environment control system and the characteristic of dry bulb temperature distribution on a large scale greenhouse in summer season.

• 한국생물환경조절학회:학술대회논문집
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• 한국생물환경조절학회 2001년도 봄 학술발표논문집
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• pp.51-56
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• 2001

This study was carried out to research the effect of nutrient composition and GA4＋7 on growth, flower quality and bulb development in special hydroponics of cut tulip. Flowering of 'Cassini' was markedly accelerated by standard+GA4＋7, K200＋GA4＋7, N250＋GA4＋7 treatment, last internode was increased by N250 as compared with other treatment. For 'Christmas Marvel', flowering was promoted by K250＋GA4＋7, last infernode and total length were also increased with K250＋GA4＋7 as compared to other treatment. For 'Golden Apeldoorn', flowering was accelerated by K200＋GA4＋7, last internode was increased with N300＋GA4＋7 treatment and total length was increased in N250＋GA4＋7 treatment as compared with the standard plants. Bulb weight and number of 'Cassini', 'Christmas Marvel'and 'Golden Apeldoorn' were decreased by GA4＋7 as compared to non-treatment, and bulb diameter was not affected by GA4＋7.

• 원예과학기술지
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• 제19권4호
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• pp.585-590
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• 2001

본 연구는 강원도 평창의 고랭지에서 1998년 5월부터 10월까지 백합의 생육 향상과 우량구근 생산을 위해 여러 가지 피복재를 재배에 이용하였다. 피복처리재는 톱밥, 흑색필름, 반사필름, 투명필름, 그리고 백흑이중필름을 사용하였다. 백합 공시 품종은 일본 수출에 유리한 'Casablanca'와 'Marco Polo'를 재식하였다. 흑색필름과 백흑이중필름 피복재배는 백합 잎의 생장과 발육을 지연시켰다. 피복재배는 'Casablanca' 품종의 지상부 생체중을 증가시켰다. 구근생장은 흑색필름과 백흑이중필름 피복구를 제외한 처리구는 무처리구와 유사한 구근 생육상을 보여주었다. 톱밥과 반사필름 피복재배가 무처리구와 다른 피복처리구보다 백합 지상부 생육, 지하부 생육, 그리고 구근생육에 유리하였다. 흑색필름은 지상부와 지하부 생육, 그리고 개화 향상에 적합하지 않은 것으로 조사되었다. 투명필름처리와 백흑이중필름은 백합재배 시 무처리구와 비교하여 지상부생육과 구근 생산에 뚜렷한 증진 효과가 없었다. 한편 피복재가 대체적으로 생육을 지연시키는 효과가 있어 관행수확기보다 수확기를 다소 늦추는 것이 백합 구근생산에 유리할 것으로 판단된다.