• 제목/요약/키워드: High Temperature Clean-up

검색결과 43건 처리시간 0.023초

스파크 점화기관 냉간 시동시 플라즈마 광촉매 복합장치에 의한 탄화수소 화합물 저감에 관한 실험적 연구 (The Study of the Effects of Nonthermal Plasma-Photocatalyst combined Reactor on Hydrocarbon Decomposition and Reduction during Cold Start and Warm-up in a SI Engine)

  • 이택헌;전광민;전배혁;신영기
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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    • pp.169-178
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    • 2001
  • Among the recent research ideas to reduce hydrocarbon emissions emitted from SI engines till light-off of catalyst since cold start are those exploiting non-thermal plasma technique and photo-catalyst that draws recent attention by virtue of its successful application to practical use to clean up the atmosphere using the feature of its relative independence on temperature. Based on the previous research results obtained with model exhaust gases using an experimental emissions reduction system that utilizes the non-thermal plasma and photo-catalyst technique, further investigation was conducted on a production N/A 1.5 liter DOHC engine during cold start to warm-up. For the effects of non-thermal plasma-photocatalyst combined reactor, 10% concentration reduction was achieved with the fuel component paraffins, and the large increase in non-fuel paraffinic components and acetylene concentrations were similar to those of base condition. However the absolute value was locally a bit higher than those of base condition since the products was made from the dissociation and decomposition of highly branched paraffins by plasma-photocatalyst reactor. Olefinic components were highly decomposed by about 75%, due to these excellent decompositions of olefins which have relatively high MIR values, and the SR value was 1.87 that is 30% reduction from that of base condition, then, the photochemical reactivity was lowered.

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천연가스 폐압발전 활성화의 당위성에 대한 열역학적 분석 (Thermodynamic Analysis on the Feasibility of Turbo Expander Power Generation Using Natural Gas Waste Pressure)

  • 하종만;홍성호;김경천
    • 한국가스학회지
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    • 제16권6호
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    • pp.136-142
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    • 2012
  • 터보팽창기를 이용한 폐압발전에서 전력생산량과 온도의 산출식의 열역학적 유도과정을 제시하였고, 전력생산량은 압력차가 아니라 압력비가 주요변수임을 밝혔다. 천연가스 폐압발전 인입부의 고압가스는 전기에너지(비용) 투입이 거의 없이 무상으로 얻어지는 에너지라는 사실을 보임으로써, 폐압이 지금까지는 별로 주목받지 못하였지만 새로운 청정에너지원 중의 하나임을 밝혔다. 공급가스 온도 보상을 위한 방법으로 팽창 후의 heating 방식을 택한다면, 전력생산과 더불어 냉열을 이용할 수 있고, 냉열이용량 만큼 heating 에너지를 줄일 수 있으므로 경제성을 배가시킬 수 있다.

나노세공체 흡착제에 의한 수소 흡착 및 저장 (Adsorption and Storage of Hydrogen by Nanoporous Adsorbents)

  • 정성화;장종산
    • 공업화학
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    • 제18권2호
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    • pp.99-110
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    • 2007
  • 21세기의 새로운 청정 에너지원으로 각광받고 있는 수소의 성공적인 활용을 위해 높은 저장 용량을 갖는 수소 저장체와 효과적인 수소 저장기술의 개발이 필요하다. 본 총설에서는 다양한 수소 저장 방법에 대해 간략히 요약하고 그 가운데 나노세공체를 이용한 저온 물리흡착에 의한 수소 저장기술의 현황에 대해 살펴보았다. 기존에 알려져 있는 고압의 압축 저장기술과 상온 고압의 수소저장 물질의 개발 이외에도 최근에는 높은 표면적과 큰 세공 부피를 갖는 나노세공체를 이용한 저온 물리흡착 방식이 개발 가능한 수소의 저장 기술의 하나로 활발히 연구되고 있다. 본 총설에서는 높은 수소 저장 용량을 위해 필요한 나노세공체의 특성을 요약하였으며 높은 표면적 및 미세 세공부피, 작은 세공 크기, 큰 정전기장 및 불포화 배위자리가 필요함을 알 수 있었다. 최근까지 보고된 나노세공체 흡착제에 의한 수소 저장 능력을 정리하였는데 현재까지 보고된 최고의 결과로는 액체 질소 온도($-196^{\circ}C$)의 약 80 기압에서 약 7.5wt%의 수소를 저장할 수 있다고 알려져 있다. 향후 지속적이고 새로운 나노세공체의 설계, 합성, 제조 및 수식에 대한 노력을 통해 수소에너지 저장에 활용될 수 있는 효과적인 수소 저장체 개발을 기대한다.

상품성 제고를 위한 고구마 수확 후 관리 및 출하기술 (Postharvest Handling and Marketing Management for Making High Salability of Sweetpotatoes)

  • Jeong, Byeong-Choon
    • 한국식품저장유통학회:학술대회논문집
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    • 한국식품저장유통학회 2001년도 임시총회 및 제18차 학술발표회 발표논문초록집
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    • pp.51-64
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    • 2001
  • The qualities including taste of sweetpotato stored during the winter which can display in the spring market in Korea are affected by availability of storage for the roots. In order to make high storage availability of sweetpotato, the postharvest handlings should be done thoroughly from the moment of harvest until shipping them to the market. A lot of procedures that must be handled carefully for improving postharvest management are as follows; digging, trimming, gathering, putting in storage containers, carrying them from field to house, curing, storing, washing, drying, selecting marketable roots, packing and shipping to the market, etc.. Sweetpotatoes have a high moisture content, and a relatively thin and delicate skin, and are sensitive to chilling, so careless postharvest handling can lead to both quantitative and qualitative losses which may be extremely high in some circumstances. From now on research has concentrated on the improvement of postharvest conditions to increase yield and lower disease rates. Storage, which makes sweetpotatoes available through out the year, benefits both the producer and the consumer. Seven very important points must be needed in order to get the best quality marketable roots in the storing of sweetpotatos : $\circled1$The storage house must be clean and sanitary, $\circled2$The crop must be harvested before the first frost to avoid low-temperature injury, $\circled3$Particular care must be taken to avoid cutting, bruising, or other injuries of the sweetpotatoes during digging, picking up, grading, placing in containers, and moving to the storage house, $\circled4$Select sound, disease-free roots for storage $\circled5$Sweetpotatoes should be stored in properly stacked containers $\circled6$Cure immediately after harvest, preferably at 32∼33$^{\circ}C$ and 90 to 95 percent relative humidity for 4 to 7 days, After curing the temperature should be reduced to 13$^{\circ}C$ to 16$^{\circ}C$ by ventilating the storage with outside air. $\circled7$Store at 12$^{\circ}C$ to 14$^{\circ}C$ and a relative humidity of 80 to 85 percent. Storage houses should be located on suitable sites and should be tightly constructed and insulated so that temperature and humidity will be uniform. Sweetpotatoes are usually not washed and graded, and lately sometimes washed, graded, waxed, before being shipped to market. Consumer packaging of sweetpotatoes in paper boxes(10-15kg) or film bags is done mainly to aid marketing. The shelf life of washed roots in consumer packs in only 1 to 2 weeks. Weight loss of roots during marketing is much less in perforated film bags than in mesh and paper bags. Perforation of 0.8 to 1kg polyethylene bags with about six 6mm holes is essential ; to lower the internal relative humidity and avoid excessive sprouting, rooting, and dampness. Development and use of better postharvest handling with good storage facilities or marketing methods can minimize sweetpotate losses and has an effect of indirectly increasing productivity and farmer’s income.

A Study on the Galvanic Corrosion for Zirconium with Titanium and 316L Stainless Steel

  • Baik, Shin-Young
    • 해양환경안전학회지
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    • 제19권3호
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    • pp.285-289
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    • 2013
  • The coastal area of Republic of Korea is very clean compared to other countries. In this reason, west coastal area of our country is a good place for breeding up a fish such as shrimp. In winter season, the heating system is required for preventing shrimp death caused by freezing in the farm. The heater in the heating system for fishery's farm is operated very severe combating corrosion due to high accumulation by feeding material and high temperature in heated sea water. Almost all manufactured heaters of STS 316L and Ti material are scrapped every year due to heavy corrosion such a general and crevice corrosion. For comparing the general and galvanic corrosion in new heater material, the test material of Zirconium (Zr), Titanium (Ti) and STS 316L are tested by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), current density-time methods and microscopic examination in a 3.5% NaCl solution. The corrosion potential (Ecor) measured by potentiodynamic polarization for Zr, Ti and STS 316L reveals -198, -250 and -450mV, corrosion current density 0.5, 2.5 and $6.5{\mu}A/cm^2$ respectively. The film resistance measured by EIS are Zr 63,000, Ti 39,700 and 316L $3,150{\Omega}$, and the current of Zr-Ti couple is $0.03{\mu}A$, whereas Zr-316L SS is $0.1{\mu}A$. According to the result of this experiment in 3.5% NaCl solution, Zr is excellent corrosion resistance material than Ti and STS 316L.

스퍼터링 공정 조건이 산화 구리 박막 특성에 미치는 영향 (Influence of Sputtering Conditions on Properties of Copper Oxide Thin Films)

  • 조재유;허재영
    • Current Photovoltaic Research
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    • 제5권1호
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    • pp.15-19
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    • 2017
  • The fossil fuel power consumption generates $CO_2$, which causes the problems such as global warming. Also, the increase in energy consumption has accelerated the depletion of the fossil fuels, and renewable energy is attracting attention. Among the renewable energies, the solar energy gets a lot of attention as the infinite clean energy source. But, the supply level of solar cell is insignificant due to high cost of generation of electric power in comparison with fossil fuels. Thus several researchers are recently doing the research on ultra-low-cost solar cells. Also, $Cu_2O$ is one of the applied materials as an absorption layer in ultra-low-cost solar cells. Cuprous oxide ($Cu_2O$) is highly desirable semiconductor oxide for use in solar energy conversion due to its direct band gap ($E_g={\sim}2.1eV$) and a high absorption coefficient that absorbs visible light of wavelengths up to 650 nm. In addition, $Cu_2O$ has several advantages such as non-toxicity, low cost and can be prepared with simple and cheap methods on large scale. In this work, we fabricated the $Cu_2O$ thin films by reactive sputtering method. The films were deposited with a Cu target with variable parameters such as substrate temperature, rf-power, and annealing condition. Finally, we confirmed the structural properties of thin films by XRD and SEM.

치환 다이페놀의 효율적 고리화 반응: 설퍼로다민B의 합성에의 응용 (Efficient Cyclization of Substituted Diphenols : Application to the Synthesis of Sulforhodamine B)

  • 박민균;심재진;나춘섭
    • 청정기술
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    • 제21권2호
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    • pp.102-107
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    • 2015
  • Rhodamine염료는 높은 흡광계수와 함께 넓은 가시광선 영역에서 고효율과 안정성을 나타내는 형광을 제공함으로써 형광표지 물질로 널리 사용되고 있다. Rhodamine 화합물을 형광표지 물질로 이용하기 위해서는 rhodamine골격을 (생체)분자나 표면에 공유결합 시키는 화학적 과정이 필수적이기 때문에 이에 관련하여 다양한 rhodamine유도체를 합성해내는 효율적이고 실제적인 방법의 개발은 큰 관심을 끌어왔다. Sulforhodamine B는 반응성이 큰 두 개의 sulfoxy작용기를 포함하고 있는데 이를 이용하여 여러 재료에 공유결합 시킴으로써 널리 활용될 수 있는 유용한 화합물이다. 본 연구에서는 4-formyl-1, 3-benzenedisulfonic acid의 disodium염과 3-diethylaminophenol으로부터 3단계에 걸쳐 sulforhodamine B를 합성하는 과정을 연구하였다. 이 과정에서 dihydroxytriarylmethane 중간체를 xanthene 골격으로 전환하는 두 번째 단계를 획기적으로 개선하는 방법에 대해 기술하였다. 이는 반응 중에 생성되는 물분자가 역반응에 참여하는 것을 억제하도록 메탄올을 가함으로써 이루어졌다. 그 결과, 반응온도는 낮아지고(135에서 80 ℃), 수율은 크게 증가되었다(20% 미만에서 84%). 이로써, 기존의 3단계에 걸친 sulforhodamine B의 제법은 에너지 절감 및 자원효율 면에서 개선된 방법으로 이루어지게 되었다.

고압상태의 다양한 용매 내에서 Poly(methylmethacrylate) (PMMA)의 상거동 (Phase Behavior of Poly(methylmethacrylate) (PMMA) in Varions Solvents at High Pressure)

  • 김제일;유기풍;임종성
    • 청정기술
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    • 제13권1호
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    • pp.28-33
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    • 2007
  • 본 연구에서는 variable volume view cell이 장착된 상평형 장치를 사용하여 고압 상태의 다양한 용매 내에서 고분자인 Poly(methylmethacrylate) (PMMA)의 구름점(cloud point)를 측정하였다. 이때 사용된 용매는 chlorodifluoromethane (HCFC-22), dimethylether (DME), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), 1,1,1,2-tetrafluoroethane (HFC-134a) 이였으며, 이들 용매에 $CO_2$를 첨가한 $HCFC-22+CO_2$$DME+CO_2$의 이성분계 혼합용매에서 $CO_2$의 조성 변화가 PMMA의 상거동에 미치는 영향을 살펴보았다. 실험 결과 PMMA는 HCFC-22에서는 340K, 5MPa 정도의 가장 낮은 온도 압력 조건에서부터 잘 용해되었으며 DME에서는 300K, 28MPa 정도의 비교적 낮은 온도 압력 범위에서 잘 용해되었으나, 그 밖의 불소화합물인 HFC-143a, HFC-152a, HFC-134a에서는 423.15K, 160MPa의 높은 온도 및 압력범위에서도 전혀 용해가 일어나지 않았다. 또한, PMMA+HCFC-22 혼합물에 $CO_2$를 첨가한 $PMMA+HCFC-22+CO_2$계의 경우는 LCST (lower critical solution temperature)의 상거동을 보였으나 PMMA+DME 혼합물에 $CO_2$를 첨가한 $PMMA+DME+CO_2$계의 경우는 UCST (upper critical solution temperature)의 상거동을 보였다. $CO_2$ 혼합용매 내에서 cloud point 압력은 동일한 온도에서 첨가되는 $CO_2$의 양에 비례하여 급격히 높아지는 것을 관찰할 수 있었고, 이로부터 PMMA를 SAS (supercritical antisolvent) 법에 의해 미세입자화 할 경우 $CO_2$가 DME와 HCFC-22에 대한 역용매로 사용될 수 있다는 것을 확인할 수 있었다. 또한 $CO_2$의 농도를 변화시킴으로써 PMMA의 cloud point를 자유롭게 조절할 수 있다는 것을 알 수 있었다.

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초임계 용매를 포함한 Poly(propyl acrylate)와 Poly(propyl methacrylate)의 이성분 및 삼성분계에 관한 상거동 (Phase Behavior on the Binary and Ternary System of Poly(propyl acrylate) and Poly(propyl methacrylate) with Supercritical Solvents)

  • 변헌수;이하연
    • Korean Chemical Engineering Research
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    • 제40권6호
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    • pp.703-708
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    • 2002
  • 본 연구는 초임계 용매인 $CO_2$, 에틸렌, 프로판, 부탄, 프로필렌, 1-부텐, 디메틸에테르 및 $CHClF_2$내에서 poly(propyl acrylate)와 poly(propyl methacrylate) 용액과의 고압 상거동을 측정하였다. 초임계 용매들과 poly(propyl acrylate) 및 poly(propyl methacrylate)간의 상거동 측정 범위는 온도 $23-186^{\circ}C$와 압력 2,400 bar까지 실험하여 나타내었다. poly(propyl acrylate)-$CO_2$ 혼합물은 약 2,070 bar 이내에서, poly(propyl acrylate)-에틸렌계는 1,400 bar 이하에서, poly(propyl acrylate)-프로판계는 1,880 bar 이하에서, poly(propyl acrylate)-프로필렌계는 450 bar 이하에서, poly(propyl acrylate)-부탄계는 2,200 bar이하에서, poly(propyl acrylate)-1-부텐계는 250 bar 이하에서, poly(propyl acrylate)-디메틸에테르계는 150 bar 이하에서 각각 용해되었으며, 이때 온도범위는 $23-175^{\circ}C$이였다. poly(propyl methacrylate)-$CO_2$ 혼합물은 2,900 bar 및 온도 $240^{\circ}C$에서도 용해되지 않았다. poly(propyl methacrylate)-프로판계는 약 2,390 bar이하에서, poly(propyl methacrylate)-부탄계에 대해서는 2,100 bar이하에서, poly(propyl methacrylate)-프로필렌계에 대해서는 570 bar 이하에서 poly(propyl methacrylate)-1-부텐계는 310 bar 이하에서, poly(propyl methacrylate)-$CHClF_2$계에 대해서는 300 bar 이하에서, 그리고 poly(propyl methacrylate)-디메틸에테르계에 대해서는 170 bar 이하에서 각각 용해되었으며, 이때 온도범위는 $40-186^{\circ}C$ 사이였다. 또한 이성분 poly(propyl acrylate)-$CO_2$와 poly(propyl acrylate)-디메틸에테르계의 상거동 사이에 디메틸에테르를 공용매로 사용하여 5, 15 및 50 wt% 첨가하여 구름점의 거동을 상임계용액온도 영역에서 하임계용액온도 영역까지 나타내었다.

무순(Raphanus sativus L.)의 제거능 계산에 의한 뿌리여과법의 우라늄 제거 가능성 평가 (Evaluation of Rhizofiltration for Uranium Removal with Calculation of the Removal Capacity of Raphanus sativus L.)

  • 한이경;이민희
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제20권7호
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    • pp.43-52
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    • 2015
  • The uranium removal capacity of radish sprouts (Raphanus sativus L.) in groundwater was calculated on the basis of the amount of uranium accumulated in the radish sprouts rather than the concentration in solution, of which process was very limited in previous studies. Continuous rhizofiltration clean-up system was designed to investigate the feasibility of radish sprouts, applying for uranium contaminated groundwater (U concentration: 110 μg/L) taken at Bugogdong, Busan. Six acrylic boxes (10 cm × 30 cm × 10 cm) were connected in a direct series for the continuous rhizofiltration system and 200 g of radish sprouts cultivars was placed in each box. The groundwater was flushed through the system for 48 hours at the constant rate of 5 mL/min. The rhizofiltration system was operated in the phytotron, of which conditions were at 25℃ temperature, 70% of relative humidity, 4,000 Lux illumination (16 hours/day) and 600 mg/L of CO2 concentration. While 14.4 L of contaminated groundwater was treated, the uranium removal efficiency of the radish sprouts (1,200 g in wet weight) was 77.2% and their removal capacities ranged at 152.1 μg/g-239.7 μg/g (the average: 210.8 μg/g), suggesting that the radish sprouts belong to the group of hyper-accumulation species. After the experiment, the sum of U amounts accumulated in radish sprouts and remained in groundwater was 1,472.2 μg and the uranium recovery ratio of this rhizofiltration experiment was 92.9%. From the results, it was investigated that the radish sprouts can remove large amounts of uranium from contaminated groundwater in a short time (few days) because the fast growth rate and the high U accumulation adsorption capacity.