• 한국생물환경조절학회:학술대회논문집
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• 한국생물환경조절학회 2001년도 봄 학술발표논문집
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• pp.41-42
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• 2001

The objectives of this study were to investigate the effect of the physical properties of wick on the water absorption of substrate. Physical properties of wick in this study were cotton composition, width and length. The water Infiltration rate through the wick was 0.24 ㎝/s at 90 -95% cotton content, which was faster than at 80-85% (0.13 cm/s) and 70-75% (0.08 cm/s). As the cotton content increased, the water absorption of substrate became greater : the amount of absorbed water was about 5-7g higher at 90-95% than at 80-85% and 70-75% at a wick width of 1 ㎝, the velocity of water absorption through the wick was fastest with 0.25 ㎝ㆍs/sup -1/. The amount of absorbed water was higher at 3 ㎝ than at 1 and 2 ㎝. However, the water absorption rate through the cross - sectional area of wick (g H₂O /㎠/hr) was higher at a wick width of 2 ㎝ than at those of 1 and 3 ㎝. The amount of absorbed water in the substrate was higher at 2 : 1 than at 1 : 1 (length in substrate : length out of substrate). Absorbed water amount was larger at 30-40% initial moisture content than any other treatment.

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.469-474
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• 2001

Milling the rice with low moisture requires more energy, produces more cracked rice, and results in reducing taste of cooked rice. Accordingly, it is necessary to add moisture to the rice with low moisture to obtain optimum moisture level for milling and taste of rice. This study was performed to evaluate the influence of initial moisture content and absorption rate on rice crack, milling energy and whiteness of milled rice and to obtain the information for design of rewetting system mounted on stirring device in grain bin. The tests were conducted for the four levels of initial moisture content in the range of 11.4 to 14.5%(w.b.) and six levels of absorption rate in the range of 0.04 to 1.0%, w.b./hr. In the case of lower moisture content below 12%(w.b.), crack ratios of brown rice were remarkably high regardless of initial moisture contents. Therefore, it was found that rough rice below 12%(w.b.) in initial moisture content could not rewetted by spraying water without crack generation of low level. Absorption rate must be below 0.3%, w.b./hr to maintain crack ratio increase of less than 1% regardless of initial moisture contents. In the case of allowable crack ratio increase of 2% and 5%, it was found that the maximum absorprion rate was respectively 0.6%, w.b./hr and 1.0%, w.b./hr in the initial moisture content of above 13.5%(w.b.). Rewetting the rough rice in moisture content of 11.4 to 14.5%(w.b.) to 14.3 to 16.9%(w.b.) decreased milling energy consumption by 15.9 to 22.3%. The effect of energy saving was higher in the samples of higher initial moisture content. Whiteness of milled rice was decreased by 0.5 to 1.5.

• Journal of Ginseng Research
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• 제44권4호
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• pp.627-636
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• 2020

Background: Cultivation of medicinal crops, which synthesize hundreds of substances for curative functions, was focused on the synthesis of secondary metabolites rather than biomass accumulation. Nutrition is an important restrict factor for plant growth and secondary metabolites, but little attention has been given to the plasticity of nutrient uptake and secondary metabolites synthesis response to soil nitrogen (N) change. Methods: Two year-field experiments of Sanqi (Panax notoginseng), which can synthesize a high level of saponin in cells, were conducted to study the effects of N application on the temporal dynamics of biomass, nutrient absorption, root architecture and the relationships between these parameters and saponin synthesis. Results: Increasing N fertilizer rates could improve the dry matter yields and nutrient absorption ability through increasing the maximum daily growth (or nutrient uptake) rate. Under suitable N level (225 kg/ha N), Sanqi restricted the root length and surface and enhanced the root diameter and N uptake rate per root length (NURI) to promote nutrient absorption, but the opposite status of Sanqi root architecture and NURI was found when soil N was deficient. Furthermore, increasing N rates could promote the accumulation of saponin in roots through improving the NURI, which showed a significant positive relationship with the content of saponin in the taproots. Conclusion: Appropriate N fertilizer rates could optimize both root architecture and nutrient uptake efficiency, then promote both the accumulation of dry matter and the synthesis of saponins.

• 생물환경조절학회지
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• 제20권1호
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• pp.33-39
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• 2011

시설재배 딸기를 위한 생력적이고 환경친화적인 순환식 수경재배기술을 확립하기 위하여 고형배지 종류별로 딸기의 무기이온 흡수 특성을 조사하였다. 톱밥배지를 제외한 나머지 세 종류의 배지에서는 대체적으로 많은 양의 질산태질소의 흡수를 나타내었는데, 펄라이트배지와 입상양면배지 보다는 코코피트배지에서 약간 높은 흡수농도를 나타내었다. 인은 톱밥배지를 제외한 세 종류의 배지에서는 초기에는 $5me{\cdot}L^{-1}$의 높은 흡수농도를 나타내었으며 생육이 진행됨에 따라 점차 감소하여 $3me{\cdot}L^{-1}$ 정도의 흡수량을 나타내었는데, 이것은 비교적 높은 농도로서 추후 검토를 할 필요가 있을 것으로 생각되었다. 그러나 톱밥배지에서는 3월 중순까지 인의 흡수가 거의 없는 것으로 나타났다. 칼륨의 흡수농도는 톱밥배지를 제외하고는 세 배지 모두 비슷한 흡수량을 나타내었는데 생육초기에는 비교적 높은 흡수량을 나타내었지만 점차적으로 감소하여 $4me{\cdot}L^{-1}$ 전후의 흡수량을 나타내었다. 칼슘의 흡수량은 펄라이트배지와 입상암면배지에서는 생육초기에 약간 높은 농도를 나타내기는 하였지만 생육전반에 걸쳐서 $2me{\cdot}L^{-1}$ 정도의 안정적인 흡수양상을 나타내었다. 마그네슘은 코코피트배지에서 생육 전반기에 $3me{\cdot}L^{-1}$ 정도의 높은 흡수농도를 나타내었으며 생육 후반기까지도 다른 배지에 비해서 가장 높은 흡수 농도를 나타내었다. 다음으로는 펄라이트 배지와 입상암면배지 순이었으며 세 배지 모두 마그네슘의 흡수는 대체적으로 $1me{\cdot}L^{-1}$ 정도의 농도를 나타내었다. 본 실험의 결과는 고형배지를 이용한 순환식 딸기 수경재배에서 유용하게 활용될 것으로 생각된다.

• 생명과학회지
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• 제32권3호
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• pp.232-240
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• 2022

리포좀을 제조하는 방법으로 여러가지 알려져 있다. 그 중 Bangham법이 가장 간단하며 일반적으로 많이 이용되어 왔다. 소규모 실험 수준에서는 효과적으로 리포좀을 제조할 수 있지만 유기용매 제거의 어려움과 지질막 형성에 반응기 크기 등의 문제로 대규모 생산을 할 수 없다는 문제점이 있다. 반면 톤(t) 단위로 대량생산이 가능한 Emulsion Method는 균일한 입자를 가진 리포좀으로 제조가 가능하나 포집률이 현저히 낮은 단점이 있다. 그래서 본 연구에서 높은 포집율과 안정성을 향상시킨 Heating Method으로 리포좀 최적의 공정방법을 개발하여 포집률, 입자크기, 제타전위 및 SD rat에 경구 투여하여 흡수율 실험을 수행하였다. 약 214 nm의 작고 균일한 리포좀을 형성하였고, 포집률은 Emulsion Method는 26.46%, Heating Method는 38.67%으로 Heating Method법을 제조된 리포좀이 높은 포집률을 보여주는 것을 확인할 수 있었다. 혈중 농도 대비 모든 군에서 1.5-2배 정도 증가한 경향을 보여주었고, 4-12 hr까지 점차 낮아지는 양상을 나타냈다. Ascorbic acid powder의 혈중 최고 농도는 약 12.017 ㎍/ml, Emulsion Method 리포좀 13.871 ㎍/ml, Heating Method 리포좀은 16.322 ㎍/ml 순으로 ascorbic acid powder보다 향상된 흡수율 결과를 보여주었다.

• 한국대기환경학회지
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• 제26권5호
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• pp.499-506
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• 2010

Recently, a great deal of attention have been directed to the use of alternative fuels as a means to reduce vehicular emissions. As one of the promising alternative fuels, bio-diesel has advantages of a wide adaptability without retrofit of diesel engine. It is also effective enough to reduce CO, THC, $SO_x$, polycyclic aromatic hydrocarbons (PAHs) and PM. In this study, we investigated the emission characteristics of biofuels between different operating conditions, i.e., engine speed (1,400 rpm and 2,300 rpm), engine load (10% and 100%), bio-diesel blending (BD0, BD5 and BD20), and recirculation (EGR) rate of exhaust gas (0% and 20%). Relative performance of the system was evaluated mainly for the greenhouse gases ($CH_4$, $N_2O$ and $CO_2$). In addition, emission characteristics of ND-13 mode were also tested against both greenhouse gases and other airborne pollutants under emission regulation. The relative composition of bio-diesel has shown fairly clear effects on the emission quantities of CO, THC, and PM emission, although it was not on $NO_x$ and greenhouse gases. EGR rate has shown trade-off characteristics between $NO_x$ and PM.

• 한국가스학회지
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• 제21권4호
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• pp.76-83
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• 2017

국내의 늘어나는 천연가스의 수요를 충족시키면서 지구온난화에 대한 대안으로 바이오가스를 도시가스로 활용하는 방안이 자연스럽게 주목받고 있다. 도시가스사업법의 개정을 통해 바이오가스의 생산 및 공급의 제도적인 기반을 구축했지만, 바이오가스내의 불순물을 제거하고 이산화탄소를 분리하여 고순도의 메탄을 제조하는 국내 기술이 부족하여 실질적인 활용이 어려운 상황이다. 따라서 본 연구에서는 고순도의 바이오메탄 농축을 위하여 멤브레인(Membrane)법, 물흡수법(Water absorption), 화학흡수법(Chemical absorption), 흡착법 4가지의 공법을 적용하여 각 시스템별 운전시나리오를 작성하고 비교하여 최적공법을 도출하였으며, 시스템별 케이스 연구를 통해 최적의 시스템을 구축할 수 있었다. 이를 이용하여 순도 97%이상의 바이오메탄을 생산하여 도시가스로 이용하기에 충분하였으며, 회수율이 98%를 넘어 그간 경제성이 없어 버려지던 소량의 바이오 가스도 회수하여 활용 할 수 있게 되었다.

• Geosystem Engineering
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• 제21권5호
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• pp.291-296
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• 2018

The aim of this work is to study the effect of aggregate type on the physico-mechanical properties and microstructure of bio-mortar (BM). Three different aggregates such as sand, dolomite and basalt were used. BM was prepared by mixing aggregates with bacterial cells (Sporosarcina Pasteurii) and one equimolar (1 M) of $urea/CaCl_2.2H_2O$. The results proved that the chemical composition and physical properties of aggregates play an important role in the microbial precipitation rate as well as size, morphology and crystallinity of the precipitated calcite, which strongly reflects on the properties of the prepared BM. The BM containing dolomite gave the highest compressive strength and lowest water absorption.

• 공업화학
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• 제19권6호
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• pp.645-651
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• 2008

본 연구에서는 30, 40, 50 wt% MDEA (N-methyldiethanolamine) 수용액을 이용하여 0~50 bar, $40{\sim}80^{\circ}C$의 조업조건에서 이산화탄소 흡수평형실험을 수행하여 연소전 이산화탄소 포집에 적용 가능한 고압조건에 대한 정보를 알고자 하였다. 또한 MDEA의 반응 속도를 증가시키기 위하여 piperazine 5.0~10.0 wt%를 첨가한 후 이산화탄소 흡수실험을 수행하였다. 그 결과 수용액 상 MDEA의 농도, 반응 온도가 증가함에 따라 평형 압력이 증가하였으며 반응온도가 높을수록 흡수속도가 증가하였다. Piperazine을 첨가한 MDEA 수용액은 MDEA 40 wt% 단독 흡수제에 비해 초기 반응에서 2.5배에 가까운 반응속도와 16% 가량 증대된 흡수능을 보였다.

• ETRI Journal
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• 제46권3호
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• pp.413-420
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• 2024

A dual-band bio-implantable compact antenna with a meander-line structure is presented. The proposed meander-line antenna resonates at the industrial, scientific, and medical (2.4 GHz) and wireless medical telemetry (1.4 GHz) bands. The meander-line structure is selected as a radiating patch given its versatile and effective design. With a dimension of only 10 mm × 10 mm × 0.635 mm, the designed antenna is compact. Considering a skin phantom, the proposed antenna was designed, optimized, and simulated. The Rogers RT/duroid 6010 substrate material with high dielectric constant was used to fabricate the meander-line dual-band implantable antenna, which was validated experimentally. The superstrate was made of the same material. Experiments were conducted on skin-mimicking gel. The designed meander-line antenna has a high peak gain of -21 dBi at 2.4 GHz, and its maximum specific absorption rate is compliant with IEEE safety standards.