• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.328-334
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• 2013

A greenhouse heating system to improve heat pump performance using inside and outside air of greenhouse as a heat source selectively and cut $CO_2$ enrichment costs by delay of greenhouse ventilation was developed. In this system, thermal storage modes divided into inside circulation mode using surplus solar energy and outside circulation mode using outside air heat. The thermal storage modes were designed to be switched mutually according to inside greenhouse temperature and six temperature values were input to control the heat pump operating, thermal storage mode switching and greenhouse heating automatically. Operating characteristics of this system were tested in a plastic greenhouse of non-ventilation condition. The results of test showed that the inside circulation mode began at about 11:00 and lasted for about 210 minutes and inside greenhouse temperature was maintained between $20{\sim}28^{\circ}C$ in spite of non-ventilation. System heating COP of the inside circulation mode in the daytime was 3.35, which was 36% and 25% higher than that of the outside circulation modes in the nighttime and daytime respectively.

• Management & Information Systems Review
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• v.30 no.1
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• pp.71-86
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• 2011

The existing tax law provides that alloted resident tax on corporation tax is apportioned in accordance with the number of employees and total building area as of the end of business year. Through a case analysis, however, this study found that such apportionment is not applied to businesses whose operation was already withdrawn as of the end of business year. To solve this problem, the study proposed that the apportionment of alloted resident tax on corporation tax should be made in accordance with the number of employees and total building area in the middle of business year and a standard of corporation tax assessment, that is, sales assessed according to the value-added tax law. This proposal already proved to be reasonable by lots of actual cases that showed the realization of balance in taxation. To make more precise standards of the above mentioned apportionment, then, the study proposed that in the ordinance of the local tax law, 'as of the end of business year' should be replaced by 'in the middle of business year'. In addition, 'in the middle of business year' should be defined as 'in the period of continuous business' from the date of business end in the previous year to the date of business end in the present year and the length of the period should be calculated by month. These moves would bring more transparent and balanced local tax assignment than present under the local tax law.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.39-48
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• 2016

In this paper, we propose thermal resistance compact model of FinFET structure that has hexagon shaped source/drain. The heating effect and thermal properties were increased by reduced size of the device, and thermal resistance is an important factor to analyze the effect and the properties. The heat source and each contact that is moved heat out were set up in transistor, and domain is divided by the heat source and the four parts of contacts : source, drain, gate, substrate. Each contact thermal resistance model is subdivided as a easily interpretable structure by analyzing the temperature and heat flow of the TCAD simulation results. The domains are modeled based on an integration or conformal mapping method through the structure parameters according to its structure. First modeled by analyzing the thermal resistance to a single fin, and applying the change in the parameter of the channel increases to improve the accuracy of the thermal resistance model of the multi-fin/ finger. The proposed thermal resistance model was compared to the thermal resistance by analyzing results of the 3D Technology CAD simulations, and the proposed total thermal resistance model has an error of 3 % less in single and multi-finl. The proposed thermal resistance model can predict the thermal resistance due to the increase of the fin / finger, and the circuit characteristics can be improved by calculating the self-heating effect and thermal characterization.

• Korean Journal of Rural Living Science
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• v.3
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• pp.37-44
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• 1992

본 연구는 충남지역 농어촌의 부엌설비 및 식사현황의 실태를 조사하여 농어촌 부엌설비 연구의 기초자료로 삼고자 1992년 3월 16일부터 2주간에 걸쳐 설문지 조사법에 의해 조사되었고 빈도(N)와 백분율(%), 그리고 변인간의 상관관계는 x$^2$-test로 통계적 유의성을 검증하였다. 1. 부엌의 구조 및 설비 1) 본 연구대상 농어촌 가정의 부엌 구조는 입식인 경우가 43.9%로서 아직까지도 재래식 구조가 많이 남아있고 부엌의 형태는 일자형(34.1%)과 자형(32.1%)이 가장 많았는데 일자형은 동선이 길고 자형은 면적을 많이 차지하는 단점을 지닌다고 하겠다. 2) 부엌 바닥의 재료는 흙바닥을 그대로 이용하는 경우(38.6%)와 콘크리트로 부엌 바닥을 마감한 경우(39.8%)가 대부분을 차지하였다. 부엌구조가 점차 입식으로 이양되면서 합성수지 제품도 이용(18.7%)되기는 했으나 흙바닥은 어떤 형태로든지 마감처리를 해야 할 것으로 본다. 3) 취사용 열원으로 가장 많이 쓰이고 있는 것은 프로판가스(57.6%)이고 그 다음으로는 연탄(16.5%)과 전기(14.9%)로서 장작과 석유의 이용율은 점차 줄어들고 있었다. 4) 상수도와 하수도시설이 부엌 내에 갖추어져 있는 비율은 각각 64.7%와 48.9%로서 아직도 미흡한 상태라고 할 수 있겠고, 정수기의 사용율은 2.9%로 관심도가 극히 낮은 편이었다. 5) 쓰레기를 분리해서 처리하는 경우는 21.8%로서 분리처리에 대한 실천이 잘 안되고 있었으며 젖은오물 처리시 비닐봉지를 사용하는 경우는 61.4%로서 과반수 이상으로 나타났다. 6) 부엌설비 중 부엌바닥재료와 취사용 열원은 가정의 수입과 positive(＋)의 상관이 있는 것으로 나타났다. 2. 가족의 식사현황 1) 주부가 식사를 담당하는 비율은 89.0%로서 높은 비율을 차지하였는데 이는 가족의 영양과 건강유지를 위하여 바람직한 일로 생각된다. 2) 식사장소로서 가장 많이 이용되는 곳은 안방(81.7%)이었으며 미비하기는 하나 그 다음으로는 부엌식당(15.6%)이었다. 이는 아직까지 농어촌지역에서 침식분리가 제대로 되어지지 않고 있다는 것을 시사해준다. 3) 가족이 모두 일주일에 5~7회 정도 식사를 함께 하는 경우가 아침식사시에는 55.1%, 저녁식사시에는 65.7%로 나타나 비교적 가족이 식사시간에 함께 모일 수 있는 여건이 마련되어 있는 것으로 여겨진다. 4) 가족의 외식횟수는 극히 적은편으로서 한달에 한번도 없거나 있어도 한번 정도인 경우가 대부분인 것(95.0%)으로 나타났다. 5) 가정내의 가공식품 이용도는 가끔 이용한다가 67.9%로 가장 많았고 주부의 직업이나 가정의 수입과는 negative(－)의 상관을 보임으로써 값싼 주식의 대용품이 많이 이용되는 것으로 사료된다. 이와 같이, 농어촌 가정의 부엌설비와 가족의 식사현황 문제를 조사해 본 결과 과거에 비해서는 좀더 합리적으로 변모하고 있다고 할 수 있겠으나 아직도 개선해야 할 점은 많은 것으로 사료된다. 그리고 앞으로 구체적이고도 현실적인 연구가 계속 이루어져야 할 것으로 기대해 본다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3353-3359
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• 2011

The co-generation system consisted of gas a turbine, a steam turbine, heat recovery steam generator and a heat exchangers for district heating was investigated in the present study. A back-pressure steam turbine (non-condensing type) was used. A partial load analysis according to the outdoor temperature in winter was conducted and optimal thermal load and power conditions was examined using the commercial computing software Thermoflex. As a result, under a constant thermal load, the power outputs of gas turbine and overall system increased as an outdoor temperature decreased. On the other hand, the reduction in exhaust gas temperature led to the decrease in output of steam turbine. Considering the portion of gas turbine in overall system in terms of the power output, it can be known that the tendency in power output of overall system was similar to that of the gas turbine.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.46-52
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• 2011

A study on the improvement for cycle efficiency of closed-type ocean thermal energy conversion (OTEC) was studied to obtain the basic data for the optimal design of cycle. For that, OTEC cycle with a generator, a reheater and a multi-turbine was simulated and analyzed. The basic thermodynamic model for OTEC is Rankine cycle and the surface seawater of $26^{\circ}C$ and deep seawater of $5^{\circ}C$ were used for the heat source of evaporator and condenser, respectively. Ammonia is used as the working fluid. The cycle efficiency increased when generator is added with 0.9 generator effectiveness. When the reheater and multi-turbine are applied in the basic cycle, the cycle efficiency showed 3.14% and the capacity of heat exchanger decreased for same total cycle power. For the OTEC cycle with the generator, the reheater and the multi-turbine showed the highest cycle efficiency and increased the efficiency by more than 6.5% comparing with the basic OTEC cycle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.616-622
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• 2016

The heating load using solar hot water is lower in summer than in the other seasons. This decreased heating load leads to the overheating solar collectors and related components. To prevent overheating of the solar collectors, air cooling and shading shields were used. On the other hand, it requires additional mechanical components, and reduces the system reliability. The geothermal heat dump system to release the high temperature heat (over $150^{\circ}C$) transferred from the heat pipe solar collectors was investigated in the present study. Research on the heat dump to cool the solar collector is rare. Therefore, the present study was carried out to collect possible data of a geothermal heat dump to cool the solar collector. A helical type geothermal heat exchanger was buried at a 1.2m depth. Experimentally and numerically, the geothermal heat dump was investigated in terms of the effects of parameters, such as the quantity of solar radiation, aperture area of the collector and the mass flow rate. A pipe length of 50m on the geothermal heat exchanger was suitable with a 0.33 kg/s flow rate. The water reservoir was a possible co-operation solution linked to the geothermal heat exchanger.

• Journal of the Korean Geotechnical Society
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• v.31 no.5
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• pp.23-33
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• 2015

In the present study, a ground heat exchanger was installed for each heat source in the system at the site to evaluate ground heat conductivity, constructability, and economic feasibility; the factors considered in the study included ground heat, groundwater, fillers (such as bentonite and pea pebbles) and the shape of the heat exchange pipe (e.g., U and D-U). The aim was to determine the ground heat exchanger appropriate for the geothermal system in the 3rd-phase construction of Incheon International Airport. A comparative cost analysis of the initial costs based on the above information showed that although the initial costs of the regular vertical closed loop-II and modified vertical closed loop were lower than those of the regular vertical closed loop-I, they could not be expected to deliver high economic efficiency from the viewpoint of constructability (filler injection, heat exchange pipe insertion). The initial costs proved to be higher in the case of Geohil.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.283-287
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• 1997

공작기계의 가공정도는 공작기계의 운동기구가 가지고 있는 기하오차와 절작작업시 발생하는 진동, 열,절삭력에 의해서 공작기계의 구조계,주축계,이송계의 변형에 의해서 직접적인 영향을 받는다. 또 가공정도는 제품의 정밀도 및 품질에 직접적인 영향을 미치기 때문에 가공정도를 향상시키기 위한 방법으로 공작기계의 오차를 측정/해석하는 방법이 연구되고 있다. 일반적으로,공작기계의 오차는 Quasi-static 오차와 Dynamic오차로 구분할수 있다. Dynamic 오차는 기계의 진동,채터 및 스핀들의 진동에 의해서만 발생하는 오차이며,Quasi-static 오차는 공작기계 구성요소인 안내면,칼럼,볼스크류등의 기하오차와 온도변화에 의한 열변형오차에 의해서 발생한다. 특히,공작기계 및 절삭가공중에 발생하는 열원에 의한 열변형 오차는 공작기계의 기하오차에 비해서 가공정도에 큰 영향을 미치며[1,2],발생오차의 약 40~70% 정도가열변형 오차에 기인한 것으로 알려져 있다[1]. 실제 많은 실험결과를 볼 때 CNC공작기계이 경우는 열변형에 의한 오차는 기하오차에 비해서 매우 크게 나타났다. 이러한 열변형 오차는 공작기계 주위 온도와 공작기계 구성요소(칼럼,이송유니크,스핀들유니트)의 비선형적인 온도 특성에 의해서 주로 발생하고, Time-variant특성을 가지고 있기 때문에 작업중에 발생하는 온도특성에 따른 열변형 오차를 최소화 할 수 있는 방법이 필요하다. 스핀들유니트는 냉각방식을 사용하여 온도변화를 줄이고 있으나 반복적인 작업과 스핀들의 고속회전으로 인해서 복합 적인 온도변화를 발생시킨다. 또, 볼스크류의 지지방식이 양쪽 고정단 형태이기 때문에 조립시 예압(pre-load)을 주어서 열팽창을 보상하고 있으나 공작기계의 반복적인 이송으로 인해서 발생하는 온도변화에 의한 열오차를 보상하는데는 어려움이 있다.됩니다. 생리적 저항력이 없는 어린이들은 이러한 공해와 생활조건의 제일희생자가 되는 것입니다. 엄마들이 "얘는 감기, 비염, 편도선을 달고 삽니다...." "얘는 코감기, 목감기 번갈아 가면서 하도 앓고 있어서 양약율 중지하고 현재 한약을 먹고 있습니다." 이러한 역경은 극복할 수 있는가\ulcorner 질병의 메카니즘은 어떻게 작용되는가\ulcorner 등등을 육미회 센타에서 체험한 사례를 가지고 말씀드리고자 합니다..ell layer (PCL)와 glia에 SOD-1이 강하게 염색되었다. APT 병용 투여로 상당수의 경련이 일어나지 않은 흰쥐는 해마의 DG에 FRA가 경미하게 염색되었고, PCL에 SOD-1도 경미하게 나타났으나, 경련이 나타난 쥐에서는 KA만을 투여한 흰쥐와 구별되지 않았다. 이상의 APT의 항산화 효과는 KA로 인한 뇌세포 변성 개선에 중요한 인자로 작용할 것으로 사료되나, 보다 명확한 APT의 기전을 검색하고 직접 임상에 응응하기 위하여는 보다 다양한 실험 조건이 보완되어야 찰 것으로 생각된다. 항우울약들의 항혈소판작용은 PKC-기질인 41-43 kD와 20 kD의 인산화를 억제함에 기인되는 것으로 사료된다.다. 것으로 사료된다.다.바와 같이 MCl에서 작은 Dv 값을 갖는데, 이것은 CdCl$_{4}$$^{2-}$ 착이온을 형성하거나 ZnCl$_{4}$$^{2-}$ , ZnCl$_{3}$$^{-}$같은 이온과 MgCl$^{+}$, MgCl$_{2}$같은 이온종을 형성하기 때문인것 같다. 한편 어떠한 용리액에서던지 NH$_{4}$$^{+}$의 경우 Dv값이 제일 작았다. 바. 본 연구

• Journal of the Korean Chemical Society
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• v.41 no.7
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• pp.329-336
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• 1997

Photoacoustic spectroscopy was utilized to investigate the carrier transport and the thermal diffusivity in GaAs and Si. From the frequency dependence of the photoacoustic signal, it is found that heat source was originated from the instantaneous thermalization process in low frequency region. In high frequency region, however, the heat was generated by the nonradiative bulk recombination and the nonradiative surface recombination processes. It was also shown that the photoacoustic effects in GaAs of a direct band gap were governed by all three processes and those in Si of an indirect band gap were produced by the instantaneous thermalization and the nonradiative bulk recombination only. The phase of the photoacoustic signal showed a minimum value in GaAs. In Si, the phase of the photoacoustic signal was monotonically decreased as the modulation frequency was increased, demonstrating the above-mentioned mechanisms of the generation of heat. By measuring the photoacoustic signal, thermal diffusivities of semiconductors were determined to be ∼0.35 ㎠/s for GaAs and ∼1.24 ㎠/s for Si. In addition, the similar values of thermal diffusivities were obtained from the curve fitting of photoacoustic phase spectra.