• 한국태양에너지학회 논문집
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• 제21권1호
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• pp.33-42
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• 2001

The paper discusses the modelling of the thermal storage roof with the air circulation system. In this system, the fully glazed absorber plate is put on the top of the conventional pitch roof made of massive concrete and acts as a solar air heater. Solar radiation collected into absorber is stored in the roof structure by radiation and convection so that it reduces the nighttime heating load through the roof. Another part of the energy is also transmitted to internal air drawn into the channel and is then introduced Into the room. To analysis the system, the energy balance equations are developed and are solved using a finite difference method. The calculation results show a good agreement with the measured ones obtained from our experiments. From the results, it is seen that the thermal storage roof with the air circulation system reduces significantly the conductive heat loss compared with that for the conventional roof and has the instantaneous solar collection efficiency of about 30%.

• 한국태양에너지학회 논문집
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• 제23권3호
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• pp.15-22
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• 2003

This study deals with the collection of solar energy and its storage in evacuated tubular collector systems for different types of header design, flow passage and heat transfer devices. In order to elicit the most efficient combination of header design, flow passage, heat transfer hardware and operating conditions, a series of tests were done for the four different types of solar collectors utilizing vacuum tubes. The systems studied here either has the evacuated collector tubes with a metal cap on one end or the all-glass evacuated solar collector tubes These evacuated tubular collectors are known to be more efficient than the flat-plate ones in both direct and diffuse solar radiation. Test results show that the system comprised of the all-glass evacuated tubes with U-shaped copper pipes inside outperforms the other configurations. Especially, a rolled copper sheet tightly placed along the inner surface of each inner tube enhances heat transfer between the heated collector surface and the water contained in the U-shaped copper pipe.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.51-53
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• 2011

제품의 데이터 수집 그리고 분류는 공장자동화를 위한 중요한 과정 중 하나이다. 공장 자동화의 컨베이어 시스템이 많은 기로를 가지면 어려움이 발생한다. 이러한 문제는 네트워크 구성이 가능한 Zig-Bee을 이용함으로서 해결할 수 있다. Zig-Bee를 이용한 네트워크는 코디네이터, 라우터 그리고 앤드디바이스로 구성이 된다. 최대 65536개의 Zig-Bee를 네트워크 형성이 가능해진다. 본 논문에서는 EM4095를 이용한 여러대의 RFID시스템과 각 RFID 시스템에 Zig-Bee 송수신 시스템을 연결하여 네트워크를 형성한 후, Tag의 데이터를 호스트 PC로 전송하는 시스템을 구현하였다.

• 한국미생물·생명공학회지
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• 제14권5호
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• pp.371-376
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• 1986

주정발효공정에서 생성되는 불순물의 분리를 위한 공정개선으로 주정원료별 불순물의 양을 알아보고 이를 super-allospas식 연속증류기에서 집적하여 효율적인 분리를 하였다. 주정발효공정중에 생성되는 불순물 중 methanol은 절간고구마가 가장 많이 생성되었고 그 다음이 타피오카였다. fusel oil중 n-propanol은 쌀, 절간고구마, 옥수수, 쌀보리 및 타피오카의 순서이고 iso-butanol은 타피오카, 옥수수, 쌀, 절간고구마 및 쌀보리의 순서였다. 그리고 iso-amyl alcohol은 타피오카, 쌀. 절간고구마 옥수수, 쌀보리의 순이었다. 한편 supper-allospas식 연속증류기에 의한 fusel oil의 분리시 alcohol함량에 따른 집적율을 보면 n-propanol은 alcohol이 78.25％(v/v)일 때 37.9％. iso-butanol은 alcohol이 68.54％ (v/v)일 때 28.6％, n-butanol은 alcohol 50％ (v/v)일 때 37.4％ iso-amyl alcohol은 alcohol이 50％ (v/v)일 때 56.1％의 가장 높은 집적율을 나타내었다. 이와 같이 집적된 불순물은 side cut 하여 후류탑으로 유입시킨 후 재차 농축하여 탑저부의 붕(plate)에서 fusel oil을 side cut하여 일부는 직접분리하고 나머지는 다시 fusel oil분리기에 넣어 alcohol이 20％(v/v) 되도록 가수하여 분리하였다.

• 한국ITS학회 논문지
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• 제3권2호
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• pp.129-140
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• 2004

본 논문에서는 지방부 간선도로 단속류 구간(국도 42호선 양지$\~$용인구간 6km)의 통행시간정보에 관한 체계적인 수집 $\cdot$ 분석을 위해 현재 국도교통관리시스템(RTMS : Rural Trafc Management System)상에서 운영중인 차량 번호판 매칭방식 AVI 수집자료에 대한 신뢰성 검증 및 단속류 구간 통행시간 자료의 적정집락간격에 관한 연구가 수행되었다. 우선 AVI수집자료 신뢰성 검증을 위하여 번호판 매칭방식 AVI표본수집자료와 전수조사자료를 Kolmogorov-Smirnov 검증기법을 이용하여 분석한 결과 AVI 자료는 통과위주의 대표차로상에서 수집되는 관계로 전차로에 대한 수집자료와 교통특성에 차이가 있어 현재의 번호판 매칭방식 AW 표본수집자료를 통해 산출된 구간통행시간을 구간의 대표값으로 적용하는 문제는 추가 검토가 필요하다. 그리고 적정집락간격을 산출하기 위하여 통계적 추정 개념인 점추정과 구간추정을 적용하여 모형을 개발하여 적용한 결과 점추정기법이 구간추정기법보다 집락간격결정에 민감하고, 보다 정확한 적정집락간격 선정이 가능한 것으로 밝혀졌으며, 적정집락간격은 5분으로 산정되어 현재 적용되고 있는 5분 집락간격은 적정한 것으로 판단된다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1520-1520
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• 2001

Food adulteration is a serious consumer fraud and a potentially dangerous practice. Regulatory authorities and food processors require a rapid, non-destructive test to accurately confirm authenticity in a range of food products and raw materials. Olive oil is prime target for adulteration either on the basis of the processing treatments used for its extraction (extra virgin vs virgin vs ordinary oil) or its geographical origin (e.g. Greek vs Italian vs Spanish). As part of an investigation into this problem, some preliminary work focused on the ability of near infrared spectroscopy to discriminate between virgin olive oils from separate regions of the Mediterranean i. e. Crete and the Peloponese. A total of 46 oils were collected: 18 originated in Crete and 28 in the Peloponese. Oils were stored in a temperature-controlled room at 2$0^{\circ}C$ prior to spectral collection at room temperature (15-18$^{\circ}C$). Samples (approximately 0.5$m\ell$) were placed in the centre of the quartz window in a camlock reflectance cell; the gold-plated baking plate was then gently placed into the cell against the glass so as to minimize the formation of air bubbles. The rear of the camlock cell was then screwed into place producing a sample thickness of 0.5mm. Spectra were recorded between 400 and 2498nm at 2nm intervals on a NIR Systems 6500 scanning monochromator. Spectral collection took place over 2-3 days. Data were analysed using both WINISI and The Unscrambler software to investigate the possibility of discriminating between the oils from Crete and the Peloponese. A number of data pre-treatments were used and discriminant models were developed using discriminant PLS (WINISI & Unscrambler) and SIMCA (Unscrambler). Despite the small number of samples involved, a satisfactory discrimination between these two oil types was achieved. Graphical examination of principal component scores for each oil type also holds out the possibility of separating oils from either Crete and the Peloponese on the basis of districts within each region. These preliminary data suggest the potential of near infrared spectroscopy to act as a screening technique for the confirmation of geographic origin of extra virgin olive oils. The sample presentation strategy adopted uses only small volumes of material and produces high quality spectra.

• 구강회복응용과학지
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• 제24권3호
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• pp.311-316
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• 2008

Calcium phosphate cement (CPC)는 우수한 생체 친화성을 바탕으로 치과 및 의과 쪽에서 성공적인 bone substitute로 사용되어 왔다. 긴 경화시간 및 washout tendency 등 CPC의 단점을 개선하기 위해 다양한 종류의 경화액 및 첨가제등에 대한 연구가 이루어졌다. 그러나 첨가제의 종류에 따른 CPC paste의 점탄성을 정량적으로 비교한 연구는 많지 않다. 이 연구에서는 2% hydroxyprophyl methylcellulose (HPMC)와 35% polyacrylic acid (PAA)의 두 가지 경화액과 혼합된 CPC의 유변학적 성질을 관찰하고 비교하고자 하였다. Dicalcium phosphate dihydrate (DCPD)를 2% HPMC 및 35% PAA와 각각 1:1의 분액비로 30초간 섞은 후 cone and plate geometry를 가지는 rheometer를 사용하여 frequency sweep test와 time sweep test를 통해 shear storage modulus (G'), shear loss modulus (G''), 그리고 complex viscosity (${\eta}^*$)를 측정하였다. 2% HPMC군과 35% PAA군의 complex viscostiy의 차이를 Mann-whitney test with Bonferroni's collection을 사용하여 분석하였다. 실험결과 2% HPMC 및 35% PAA 군 모두에서 shear thinning과 yield behavior등 pseudoplastic property를 보였으며 complex viscosity는 HPMC 군에서 PAA 군보다 통계적으로 유의성 있게 높았다. (p<0.05).

• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.831-840
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• 1997

Core/shell structured composite metal oxides of Fe2O3/MgO were prepared by thermal decomposition of Fe(acac)3 adsorbed on the surface of MgO cores. The morphology of the composites conformed to that of the MgO used as the cores. Broad powder X-ray diffraction peaks shifted toward larger d, large BET surface area (∼350 m2/g), and the size of crystalline domains in nano range (4 nm), all corroborate to the nanocrystallinity of the Fe2O3/MgO composite which was prepared by using nanocrystalline MgO as the core. By use of microcrystalline MgO as the core, microcrystalline Fe2O3/MgO composite was prepared, and it had small BET surface area of less than 35 m2/g. AFM measurements on nanocrystalline Fe2O3/MgO showed a collection of spherical aggregates (∼80 nm dia) with a very rough surface. On the contrary, microcrystalline Fe2O3/MgO was a collection of plate-like flat crystallites with a smooth surface. The nitrogen adsorption-desorption behavior indicated that microcrystalline Fe2O3/MgO was nonporous, whereas nanocrystalline Fe2O3/MgO was mesoporous. Bimodal distribution of the pore size became unimodal as the layer of Fe2O3 was applied to nanocrystalline MgO. The macropores in a wide distribution which the nanocrystalline MgO had were absent in the nanocrystalline Fe2O3/MgO. The decomposition of CCl4 was largily enhanced by the overlayer of Fe2O3 on nanocrystalline MgO making the reaction between nanocrystalline Fe2O3/MgO and CCl4 be nearly stoichiometric. The reaction products were environmentally benign MgCl2 and CO2. Such an enhancement was not attainable with the microcrystalline samples. Even for the nanocrystalline MgO, the enhancement was not attained, if not with the Fe2O3 layer. Without the layer of Fe2O3, it was observed that the nanocrystalline domain of the MgO transformed into microcrystalline one as the decomposition of CCl4 proceeded on its surface. It appeared that the layer of Fe2O3 on the particles of nanocrystalline Fe2O3/MgO blocked the transformation of the nanocrystalline domain into microcrystalline one. Therefore, in order to attain stoichiometric reaction between CCl4 and Fe2O3/MgO core/shell structured composite metal oxide, the morphology of the core MgO has to be nanocrystalline, and also the nanocrystalline domains has to be sustained until the core was exhausted into MgCl2.

• 한국식생활문화학회지
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• 제17권3호
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• pp.315-328
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• 2002

The purpose of this study was to analyze the problems arising from the actual conditions of the Foodbank, and to implement the HACCP system as a solution in terms of increasing the safety of donated food within the Foodbank. In order to apply HACCP system, the entire Foodbank working process such as preparation, collection, transportation, division, and distribution was considered and analyzed to decide the application point for CCPs. Donated foods mainly consisted of processed foods, raw materials, lunch boxes, and cooked foods from mass catering establishments, which dominated over the others in terms of quantity. Cooked foods were divided into three groups based on menu-types and processing methods. Temperature, pH, and aw were measured on cooked foods, and Total Plate Count, Coliforms, E. coli, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and E. coli O157:H7 were conducted in order to apply a HACCP plan. From these experiments, temperature, pH, and $a_w$ of donated food were likely contributed to microbial growth. Donated foods before HACCP implementation showed high numbers in terms of total plate count and Coliforms, both well over the acceptable standard levels. By setting the CCPs on maintenance of donated food below $10^{\circ}C$ and using a $75^{\circ}C$ reheating method, microbiological hazard levels were able to be controlled and lowered. From these results, it is concluded that in order to guarantee food safety, foods donated to the Foodbank must not only maintain a reasonable level of initial microbiological growth, but also must be handled properly through time and temperature controls within the Foodbank system. Furthermore, in terms of implementing the HACCP plan within the Foodbank management structure, basic food safety and sanitation measures, such as reheating facilities and various cold chain systems such as refrigerated vehicle for food transportation are importantly needed. The training and education of Foodbank personnel and management in areas such as awareness of hygiene and safe food handling and practice are also required and necessary.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.281-287
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• 2016

Purpose: The purpose of this study is to develop a walking-type two-row sesame reaper, which can simultaneously perform the cutting and collecting of sesame plants and other crops like perilla and soybean. Methods: The factors involved in reaping sesame were determined experimentally in order to design a prototype of the sesame reaper. The prototype is made up of four parts for cutting, conveying, collecting, and running. The height of two disc-plate saw blades on the cutting part is adjusted by an adjusting wheel, and peripheral speed is adjusted in accordance with the running speed. The conveying belt of the conveying part can be tilted from $0^{\circ}$ to $90^{\circ}$. The collecting part extracts a predetermined amount of transferred sesame plants. The prototype was used to evaluate the performance at different working speeds, so that the work efficiency can be calculated. Results: The center of gravity of the sesame plants was 900 mm, measured from the end of the cut stem. The diameter of the disc-plate saw blade was determined to be 355 mm, peripheral speed was 20.4-32.7 m/s, and the picking height of the conveying belt for sesame was 130 mm. The performance of transfer and collection of the sesame, when the insertion angles were $60^{\circ}$ and $90^{\circ}$, proved to be excellent. However, when the angle was over $120^{\circ}$, the performance was only 75-80%. The performance was at 100% efficiency when the ratio between running speed and conveying belt speed of the prototype was 1:2, which seems to be the ideal ratio for the sesame reaper. Conclusions: A sesame reaper was developed, which can integrate the processes of cutting, conveying, and collecting, by investigating and considering various factors involved in the reaping process. The sesame reaper can reduce the costs for yielding and producing sesame due to its highly efficient performance.