• 한국농공학회논문집
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• 제61권4호
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• pp.23-32
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• 2019

Increasing crop production with the same amount of resources is essential for enhancing the economy in agriculture. The first prerequisite is to understand relationships between the resources. The concept of WEF (Water-Energy-Food) nexus analysis was first introduced in 2011, which helps to interpret inter-linkages among the resources and stakeholders. The objective of this study was to analyze energy-water nexus in greenhouse cultivation by estimating reference evapotranspiration and heating load. For the estimation, this study used the physical model to simulate the inside temperature of the agricultural greenhouse using heating, solar radiation, ventilated and transferred heat losses as input variables. For estimating reference evapotranspiration and heating load, Penman-Monteith equation and seasonal heating load equation with HDH (Heating Degree-Hour) was applied. For calibration and validation of simulated inside temperature, used were hourly data observed from 2011 to 2012 in multi-span greenhouse. Results of the simulation were evaluated using $R^2$, MAE and RMSE, which showed 0.75, 2.22, 3.08 for calibration and 0.71, 2.39, 3.35 for validation respectively. When minimum setting temperature was $12^{\circ}C$ from 2013 to 2017, mean values of evapotranspiration and heating load were 687 mm/year and 2,147 GJ/year. For $18^{\circ}C$, Mean values of evapotranspiration and heating load were 707 mm/year and 5,616 GJ/year. From the estimation, the relationship between water and heat energy was estimated as 1.0~2.6 GJ/ton. Though additional calibrations with different types of greenhouses are necessary, the results of this study imply that they are applicable when evaluating resource relationship in the greenhouse cultivation complex.

• 한국산학기술학회논문지
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• 제20권9호
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• pp.204-210
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• 2019

터널 내부에서의 화재의 경우 일반도로와 달리 운전자의 시야 확보가 어려워 대형사고가 발생할 가능성이 매우 높다. 따라서 터널 내부 화재 발생 시 제트팬 용량에 따른 제연 효과에 관한 연구가 필요하다. 본 연구에서는 NIST에서 개발한 화재시뮬레이션인 FDS를 사용하여 제트팬의 유무, 제트팬의 용량에 의해 터널 내부에서 발생한 차량 화재에 대한 제트팬 용량에 따른 연기 거동 및 가시거리, 일산화탄소의 농도를 분석하였다. HRRPUA(Heat Release Rate Per Area)는 $3.6MW/m^2$로 설정하였으며, 모든 해석 시간은 총 600s로 설정하였다. CFD에 의한 가시거리, 일산화탄소 농도 해석은 y=30m, y=110m에서 결과를 확인하였으며 직경과 유량에 따라 연기거동 분석, 가시거리 분석, 일산화탄소 농도를 확인하였다. 제트팬의 직경과 유량이 커질수록 y=30m 후방에서 높은 가시거리를 확인할 수 있으며 일산화탄소 농도가 0ppm임을 확인하였다. 제트팬 직경과 유량이 큰 조건에서는 제트팬 유동의 상류 방향으로 대피하면 인명피해를 최대한 줄일 수 있을 것으로 판단된다.

• 한국재난정보학회 논문집
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• 제18권3호
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• pp.574-580
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• 2022

연구목적: 옥수수유는 반건성유로서 불건성유보다 이중결합의 수가 많고 산소와 결합하기 쉬우므로 자연발화의 조건이 충족되면 적은 양으로도 가연성 물질에 흡착될 경우에는 자연발화가 쉽게 발생된다. 또한 최근 자연발화의 원인 중 산화열에 의해 기름이 묻은 헝겊 등에 의한 사고가 늘어나고 있다. 그러므로 65℃에서 타올의 매수와 옥수수유의 양에 따른 자연발화의 특성을 파악하고자 한다. 연구방법: 실험온도를 65℃로 설정한 후 타올 한 장당 25ml, 50ml, 75ml에 해당하는 옥수수유를 분사시킨 후 시료의 중심 온도가 설정된 온도보다 상승하고, 타올이 연소로 인해 탈 경우에는 발화로 판정하였으며, 시료의 중심 온도가 설정된 온도와 유사할 경우에는 비발화로 판정하였다. 연구결과: 옥수수유를 타올 한 장 당 25ml씩 골고루 분포시킨 후 실험을 한 결과 타올이 5장 일 때는 비발화되었으며, 타올이 10장, 15장일 때는 발화되었다. 또한 옥수수유를 타올 한 장 당 50ml, 75ml씩 사용하여 실험한 결과 타올이 5장, 10장, 15장일 때 자연발화가 발생되었다. 결론: 옥수수유가 적은 양으로도 자연발화의 조건을 충족하면 화재가 발생할 수 있다.

• Journal of Acupuncture Research
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• 제26권6호
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• pp.31-39
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• 2009

Objectives : To characterize the thermal properties of several Korean electric moxibustion apparatus and to suggest methods for improving their quality for related industry as well as the welfare of Korean. Methods : We reviewed previous literatures on traditional moxibustion to find necessary factors for electric moxibustion apparatus. We measured the thermal characteristics of electric moxibustion apparatus commercially available by using an automatic temperature acquisition system in a controlled environment. Uniformity and heat loss of the apparatus were also analysed. We followed the user's manuals of apparatus provided by manufacturers. Results : Temperature control of all apparatus could not be achieved by automatic manners. Most of them were dependent on user's discretion. Maximum temperatures obtained were barely in the therapeutic temperature of $40-45^{\circ}C$. Unnecessary heating of moxibustion parts was detected. Chemicals from moxa were not properly delivered to the human skin. Conclusions : Temperature control of all apparatus needs to be improved in terms of temperature setting, retention time and maximum temperature. Design should be altered to utilize pharmacological effects from moxa to obtain its maximum efficacy. User's manuals should be revised for its clarity.

• 한국건설순환자원학회논문집
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• 제8권1호
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• pp.1-7
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• 2020

고로슬래그 미분말은 뛰어난 장기 강도와 염해 저항성 등을 바탕으로 활발히 사용되는 혼화재들 중 하나이다. 국내 규격(KSF 2563)은 저분말도 GGBFS를 가지고 있는 일본 및 영국의 규격과는 다르게 3종의 GGBFS가 모두 고분말도에 포함된다. 본 연구에서는 4,000급 고로슬래그 미분말와 플라이애시를 혼입한 수화열 저감용 삼성분계 배합과 3,000급 GGBFS를 혼입한 배합의 굳지 않은 콘크리트 특성, 압축 강도, 수축 특성을 분석하였다. 수화열 저감용 삼성분계 배합과 저분말도 고로슬래그 미분말을 혼입한 배합 간에 공기량과 슬럼프는 동일한 값을 나타내었으며 초결 및 종결 시간의 경우 20분 내외의 결과를 나타내어 큰 차이가 나타나지 않았다. 압축 강도와 수축 특성 분석에서 삼성분계 배합은 저분말도 GGBFS를 혼입한 배합보다 더 낮은 장기 강도와 높은 수축량을 나타내었다.

• 한국염색가공학회지
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• 제18권3호
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• pp.49-58
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• 2006

The purpose of this study was to examine the effect of covering yarn's twist on mechanical properties of knitted fabrics of composite yarns with single covering process. Four yarns that were used in this study: two different composite yarns made from the four kinds of cotton and functional polyester-(Poly-A) with the ratio of 52:48, and the rest two yarns are the original cotton 100% yarn and the poly-A 100% yarn. The two kinds of composite yarns, CP1 and CP2, were processed on the single covering process. CP1 was applied on the single covering process with S-800 tpm, where Poly-A was used as covering yarn and cotton was used as core yarn. CP2 was applied on the same process as CP1 except that Poly-A had been applied on the two-for-one twisting process with S-400 tpm on the previous step. Sixteen mechanical properties of all the four knifed fabrics knitted under the same knitting conditions were measured by KES-FB system with the outer knit condition. And 3D CAD dressmaking simulations, which were driven by some of the mechanical properties, were presented. The results were as follows: CP2 had high RT values with twisting of covering yarn. CP2 also had high B, 2HB values because of higher linear density. SMD was affected rather by twisting of covering yarn than by fine hair of the cotton surface. Twisting of covering yarn made it decreasing T value and increasing W value. Dressmaking 3D CAD simulations showed that there are buckling effects on CP2 because of high bending rigidity and shear rigidity.

• 패션비즈니스
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• 제13권1호
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• pp.102-114
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• 2009

Chitosan is a polysaccharide with cationic amino groups in its structure and has useful properties as functional materials. Various end-use developments of chitosan are in progress. When the cotton fabric is pretreated with chitosan, the hand property of cotton fabric may be improved expecially for the summer apparel. In this study, as a cross-linking agent to introduce chitosan into cotton, BTCA(butane-1,2,3,4-tetracarboxylic acid) or CA(citric acid) was added in order to prevent detachment of chitosan by the cross-linking. During the cross-linking procedure, via the padding-drying-heat setting, amino groups of chitosan and hydroxyl groups of cotton, carboxyl groups of BTCA/CA are cross-linked by forming anhydrous cyclic rings. Since BTCA has four carboxyl groups, cross-linking by thermal treatment is easy, leading to the trials in wrinkle-recovery treatment of cotton fabrics. However, the high price of the BTCA reagent has been a shortcoming in the actual application for industrial use. Therefore, in this study, we tried the application of CA having three carboxyl groups, which is relatively low priced, as the substituting cross-linking agent. The hand of the treated fabrics were evaluated by measuring physical properties. In addition, based on the physical properties, three-dimensional images were introduced by using 3D CAD systems and results were compared.

• 대한한의학원전학회지
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• 제29권1호
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• pp.1-15
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• 2016

Objectives : The purpose of this study is to investigate the method of setting up logic and estimate Fang Youzhi's work through Shanghanluntiaobian. Methods : Wang Shuhe's old edition Shanghanlun and Fang Youzhi's Shanghanluntiaobian were compared and several essential provisions were analyzed and addressed the positive and negative aspects of Fang Youzhi's revising old edition Shanghanlun mixed bamboo tablets. Results : Fang Youzhi's changing Bianmaifa("辨脈法") and Pingmaifa("平脈法") and placement Bianchishiyemaizhengbingzhi chapter after Liujingbingmaizhengbingzhi for discriminating convulsion dampness summer heat stroke from febrile diseases is appropriate. Fang Youzhi's deletion Shanghanli("傷寒例") chapter that has a guiding characteristics shows his editorial policy. Fang Youzhi's addition Bianwenbingfengwenzabingmaizhengbingzhi chapter is for discriminating febrile disease from epidemic febrile disease wind warmth syndrome miscellaneous disease and it indicates Shanghanlun is a book of treatment after differentiation of syndromes containing epidemic febrile disease and miscellaneous disease. Through Fang Youzhi's revising method I can see several positive aspects. First he tried to refine the logic of the content of Shanghanlun and accord with an actual situation. Second he shows Shanghanlun is a book of treatment after differentiation of syndromes containing epidemic febrile disease and miscellaneous disease and tried to see Shanghanlun clearly. A criticism of the Preserving Old Edition Shanghanlun group could interrupt flexibility and creative thinking reading Shanghanlun and a criticism to the Sangangdingli Principles of the several exegetists is a productive criticism because medicine treats human being so it cannot be completed by a logic. Conclusions : All of these processes are Fang Youzhi's endeavour for strengthening the system and logicality of the old edition Shanghanlun and it is meaningful to show a method to read Shanghanlun to beginners.

• Journal of Power Electronics
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• 제4권3호
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• pp.138-151
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• 2004

In this paper, a constant frequency phase shifting PWM-controlled voltage source full bridge-type series load resonant high-frequency inverter using the $4^{th}$ generation IGBT power modules is presented for innovative consumer electromagnetic induction heating applications, such as a hot water producer, steamer and super heated steamer. The bridge arm side link passive capacitive snubbers in parallel with each power semiconductor device and AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is evaluated and discussed on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency inverter topology, what is called, DE class type, including the variable-power variable-frequency regulation function can expand zero voltage soft switching commutation area even under low output power setting ranges, which is more suitable and acceptable for newly developed induction heated dual pack fluid heaters. Furthermore, even the lower output power regulation mode of this high-frequency load resonant tank inverter circuit is verified so that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

• 대기
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• 제22권1호
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• pp.73-85
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• 2012

The collision efficiency data for collision between graupel or hail particles and cloud drops that take into account the differences of particle density are applied to the Takahashi cloud model. The original setting assumes that graupel or hail collision efficiency is the same as that of the cloud drops of the same volume. The Takahashi cloud model is run with the new collision efficiency data and the results are compared with those with the original. As an initial condition, a thermodynamic profile that can initiate strong convection is provided. Three different CCN concentration values and therefore three initial cloud drop spectra are prescribed that represent maritime (CCN concentration = 300 $cm^{-3}$), continental (1000 $cm^{-3}$) and extreme continental (5000 $cm^{-3}$) air masses to examine the aerosol effects on cloud and precipitation development. Increase of CCN concentration causes cloud drop sizes to decrease and cloud drop concentrations to increase. However, the concentration of ice particles decreases with the increase of CCN concentration because small drops are difficult to freeze. These general trends are well captured by both model runs (one with the new collision efficiency data and the other with the original) but there are significant differences: with the new data, the development of cloud and raindrop formation are delayed by (1) decrease of ice collision efficiency, (2) decrease of latent heat from riming process and (3) decrease of ice crystals generated by ice multiplication. These results indicate that the model run with the original collision efficiency data overestimates precipitation rates.