• Title/Summary/Keyword: 수증기

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Study on Synthesis of Dimethyl Ether Using Silica Membrane Reactor (Silica막 반응기를 이용한 Dimethyl Ether 합성에 관한 연구)

  • Sea Bongkuk;Youn Min-Young;Lee Kew-Ho
    • Membrane Journal
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    • v.15 no.4
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    • pp.330-337
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    • 2005
  • Water selective silica membranes were prepared fur use as membrane reactor for synthesis of dimethyl ether (DME) by methanol dehydration. Silica membranes formed on a Porous SUS tube by ultrasonic spray Pyrolysis (USP) and chemical vapor deposition (CVD) using tetraethoxysilane (TEOS) as precursor. The CVD-derived membranes formed higher level of trade-off line between water permeance and water/methanol selectivity than that of the USP-derived membranes. The membrane reactor possessing water permeance of $1.2\times10^{-7}\;mol\;{\cdot}\;m^{-2}\;{\cdot}\;S^{-1}\;{\cdot}\;Pa^{-1}$ and water/methanol selectivity of 10 exhibited increase in methanol conversion of about $20\%$ comparing to conventional reactor system. These findings led us to conclude that the dehydration membrane reactor simultaneously separating the water vapour produced in the reaction zone was effective in increasing the reaction conversion.

Study on $H_2O$ plasma by using VHF ICP (VHF ICP를 이용한 $H_2O$ 플라즈마 연구)

  • Kim, Dae-Woon;Choo, Won-Il;Jeon, Ye-Jin;Lee, Seung-Heun;Joo, Jung-Hoon;Kwon, Sung-Ku
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.459-459
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    • 2007
  • VHF ICP (Very High Frequency Inductively Coupled Plasma) 반응기에서 반응기 압력, 수증기 유량, 플라즈마 출력, 반응기온도 등의 공정변수에 따른 수증기 분해특성과 수소생성거동을 실험하였다. 플라즈마 분해 특성은 OES(Optical Emission Spectroscopy)를 사용하여 분석하였으며, QMS(Quadrapole Mass Spectroscopy)를 이용하여 배기가스 성분을 분석하여, 수증기 분해거동 및 수소생성 효율을 조사하였다. 본 연구실에서 설계한 초고주파 유도결합 플라즈마는 고밀도 플라즈마 생성과 낮은 압력에서도 안정된 플라즈마 발생 특징을 나타내었다. 플라즈마 출력의 증가에 따른 수증기의 분해와 수소생성 거동은 개시영역, 선형증가영역, 포화영역의 세 영역으로 구분되는 특징을 나타내었다. 유량 및 압력의 증가에 따라 포화에 필요한 플라즈마의 출력이 증가되는 경향을 나타내었다. 본 실험의 온도범위에서는 온도 증가에 따른 수증기 분해 및 수소생성 증가효과는 플라즈마 출력의 영향에 비하여 매우 미미한 정도로 플라즈마의 높은 에너지 전달효과를 확인할 수 있었다. 따라서, 낮은 반응기 온도에서도, 유량 및 압력에 따른 포화 플라즈마조건을 설정할 경우, 높은 에너지 효율의 수소 제조가 가능함을 알 수 있었으며, 물분해 플라즈마를 이용한 저온 산화물 박막증착에의 적용도 기대된다.

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Effect of Vapor-dam Treatment on the Air Circulating oven Drying Characteristics of Bamboo Tubes (수증기댐 처리가 통죽(筒竹)의 송풍오븐건조 특성에 미치는 영향)

  • Lee, Nam-Ho;Jung, Hee-Suk;Hayashi, Kazuo;Li, Cheng-Yuan;Zhao, Xue-Feng;Hwang, Ui-Do
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.1
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    • pp.11-16
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    • 2007
  • This study was carried out to investigate the effect of Vapor-dam treatment on drying drying rates, prevention of checks and V-shaped split during air circulating oven drying bamboo (Phyllostachys pubescens Mazel et Z) tube. It was shown that the drying time from green to around 7~8 % of moisture content was required less as drying schedule was more severe, and distinctly dominated by the drying rate during the initial drying stage. Area shrinkages in cross section and thickness shrinkages measured during air circulating oven drying test were very large. Surface checks and V-shaped splits were occurred in untreated samples just after the beginning of drying, while sixty seven percentages of all the Vapor-dam treated samples could be produced without drying defects. The V-shaped splits occurred in the Vapor-dam treated samples were influenced more by the sealing of the vapor evaporation through the cross section than drying schedule.

Relationship between RVA Properties and Film Physical Properties of Native Corn Starch and Hydroxypropylated Corn Starch (천연옥수수전분과 hydroxypropyl화 옥수수전분의 RVA특성과 필름 물성의 관계)

  • Han, Youn-Jeong;Kim, Suk-Shin
    • Korean Journal of Food Science and Technology
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    • v.34 no.6
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    • pp.1023-1029
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    • 2002
  • Relationship between RVA properties and physical properties of film made from native corn starch and hydroxypropylated corn starch at various levels of plasticizers was examinel. Tensile strength of the film decreased, but its elongation and water vapor permeability increased with increasing plasticizer concentration. The film with glycerol showed greater changes in physical properties than that with sorbitol. Hydroxypropylated starch film showed lower tensile strength, higher elongation, and higher water vapor permeability than the native starch film. Sorbitol resulted in films with relatively high tensile strength, whereas glycerol produced films with increased elongation. The most reliable parameters for the relationship between RVA properties and film properties were RVA peak viscosity, tensile strength, and water vapor permeability. Water vapor permeability and tensile strength had linear relationship with RVA properties. The tensile strength and water vapor permeability of film could be predicted using the RVA peak viscosity.

Cleaning System Design using Supper Heating Steam (과열 수증기를 이용한 세정 시스템 설계)

  • Cho, Do-Hyeoun
    • 전자공학회논문지 IE
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    • v.48 no.2
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    • pp.47-51
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    • 2011
  • In this paper, we propose the cleaning process system to remove micro-particles, various impurities, unnecessary residues, etc. for liquid crystal display manufacturing processes. This system is structured with cleaning, rinse and drying process using the chemical cleaning of alkaline water and the physical cleaning of SHS(supper heating steam). And we shows cleaning effects of alkaline water and remove effects of SHS.

Moisture Transport Observed by Water Vapor Isotopes in the Vicinity of Coastal Area, Incheon, Korea (수증기안정동위원소를 이용한 해안지역 수분의 이동경로에 관한 연구)

  • Lee, Jeonghoon;Choi, Heejin;Oh, Jinman;Na, Un-Sung;Kwak, Hoje;Hur, Soon Do
    • Economic and Environmental Geology
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    • v.46 no.4
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    • pp.339-344
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    • 2013
  • Water vapor isotopes can be excellent tools for understanding complex mechanisms in the water cycle and atmospheric hydrological cycle and they can be applied to various fields of paleoclimatology, atmospheric science, hydrogeology, oceanography, and ecohydrology. Thus, studies of global or local transport of water vapor may be able to provide a very useful clue to better understand the movements of water and energy in the atmosphere, hydrosphere and biosphere. In this study, the isotopic compositions of water vapor have been observed for moisture transport during the passage of Typhoon Bolaven at Korea Polar Research Institute (KOPRI), Incheon, in the western part of Korea, from August 27 to August 29, 2012. In the clear sky, the isotopic compositions of water vapor at KOPRI exhibited relatively higher isotopic ratios, which were near isotopic equilibrium with sea surface water (${\delta}^{18}O$=-14‰). On the other hand, a largely depleted isotopic ratios in surface water vapor were observed in association with the passage of Typhoon Bolaven (approximately 10‰ depleted compared to the clear sky). The fact that the isotopic minima in water vapor are encountered during the onset period of the Typhoon Bolaven with increases of relative humidity, which is consistent with, so called, "the amount effect".

Physical Properties of Locust Bean Gum-Based Edible Film (Locust Bean Gum으로 제조한 가식성 필름의 물리적 특성)

  • Choi, Soo-Jin;Kim, Sang-Yong;Oh, Deok-Kun;Noh, Bong-Soo
    • Korean Journal of Food Science and Technology
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    • v.30 no.2
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    • pp.363-371
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    • 1998
  • Locust bean gum (LBG)-based edible film was prepared, and opacity, water vapor permeability (WVP), tensile strength (TS) and elongation (E) of the film were measured. Opacity values of the film was a little higher than that of other transparent films. WVP decreased as LBG concentration decreased. Plasticizers and drying temperature didn't seem to influence WVP. WVP of the film increased greatly at 85% RH as compared to that of 0% RH. WVP of the film seemed to increase linearly with thickness of the film. But WVP of the film was lower those of other edible films. TS increased with increase of LBG concentration, and decreased with increase of glycerol concentration. E decreased with increase of LBG concentration, and increased with increase of sorbitol concentratin. LBG-based composite films were prepared by adding agarose, k-carrageenan or xanthan gum. TS and E of the composite film with addition of k-carrageenan increased.

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Insecticidal activity of coriander and cinnamon oils prepared by various methods against three species of agricultural pests (Myzus persicae, Teyranychus urticae and Plutella xylostella) (농업해충 (복숭아혹진딧물, 배추좀나방 및 점박이응애)에 대한 다양한 방법에 의하여 준비된 고수와 계피 정유성분의 살충 효과)

  • Park, Bueyong;Lee, Myung-Ji;Lee, Sang-ku;Lee, Sang-Bum;Jeong, In-Hong;Park, Se-Keun;Jeon, Ye-Jin;Lee, Hoi-Seon
    • Journal of Applied Biological Chemistry
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    • v.60 no.2
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    • pp.137-140
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    • 2017
  • Agricultural pests, diamondback moth (Plutella xylostella), green peach aphid (Myzus persicae) and two-spotted spider mite (Teyranychus urticae), are becoming major pests in human dwellings in a variety of ways across the world. For management of these pests, the essential oils of Coriandrum sativum and Cinnamomum cassia prepared by steam distillation, hexane extraction and supercritical extraction methods were evaluated for the insecticidal effects. Using the contact bioassay, the $LD_{50}$ value of C. sativum oil by steam distillation extraction method was $30.59{\mu}g/cm^2$ against M. persicae adults. The $LD_{50}$ values of C. cassia oils prepared by steam distillation and hexane extraction methods were 5.96 and $4.64{\mu}g/cm^2$, respectively, against T. urticae adults, and $LD_{50}$ value of the essential oil by supercritical extraction method was $6.50{\mu}g/cm^2$ against M. persicae adults. This study showed that C. sativum and C. cassia oils could be an effective natural acaricide and insecticide against agricultural pests.

Effects of Operating Conditions on Adsorption and Desorption of Benzene in TSA Process Using Activated Carbon and Zeolite 13X (활성탄과 제올라이트 13X 충진탑을 사용한 TSA 공정에서 조업조건이 벤젠의 흡착 및 탈착에 미치는 영향)

  • Jung, Min-Young;Suh, Sung-Sup
    • Applied Chemistry for Engineering
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    • v.29 no.5
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    • pp.594-603
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    • 2018
  • The effects of operating conditions such as benzene concentration, nitrogen flow rate, steam flow rate, and bed temperature on TSA process were experimentally investigated as a potential VOC removal technology using two kinds of beds packed with activated carbon and zeolite 13X. The TSA cycle studied was composed of the adsorption step, steam desorption step, and drying and cooling step. At 2% benzene concentration, the total adsorption amounts of zeolite 13X and activated carbon were 4.44 g and 3.65 g, respectively. Since the zeolite 13X has a larger packing density than that of the activated carbon, the larger benzene amount could be adsorbed in a single cycle. Increasing the water vapor flow rate to 75 g/hr at 2% benzene concentration reduced the desorption time from 1 hr to a maximum of 33 min. If the desorption time is shortened, the drying and cooling step period can be relatively increased. Accordingly, the steam removal and bed cooling could be sufficiently performed. The desorption amounts increased with the increase of the bed temperature. However, the energy consumption increased while the desorption amount was almost constant above $150^{\circ}C$. In the continuous cycle process, when the amount of remained benzene at the completion of the regeneration step increased, it might cause a decrease in the working capacity of the adsorbent. The continuous cycle process experiment for zeolite 13X showed that the amount of remained benzene at the end of regeneration step maintained a constant value after the fourth cycle.

Evaluation of Spalling Property and Water Vapor Pressure of Concrete with Heating Rate (가열 속도에 따른 콘크리트의 폭렬 특성 및 내부 수증기압력 평가)

  • Choe, Gyeong-Cheol;Lee, Tae-Gyu;Nam, Jeong-Soo;Park, Byung-Keun;Kim, Gyu-Yong
    • Journal of the Korea Concrete Institute
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    • v.24 no.5
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    • pp.605-612
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    • 2012
  • Spalling of concrete occurs due to vapor pressure ignited explosion, temperature difference across a section, and combination of these factors. Factors affecting spalling can be classified into internal and external factors such as material property and environmental condition, respectively, have to be considered to precisely understand spalling behavior. An external environmental factor such as differences in heating rate cause internal humidity cohesion and different vapor pressure behavior. Therefore, spalling property, vapor pressure and thermal strain property were measured from concrete with compressive strengths of 30 MPa, 50 MPa, 70 MPa, 90 MPa, and 110 MPa, applied with ISO-834 standard heating curve of $1^{\circ}C/min$ heating rate. The experimental results showed that spalling occurred when rapid heating condition was applied. Also, when concrete strength was higher, the more cross section loss from spalling occurred. Also, spalling property is influenced by first pressure cancellation effect of thermal expansion caused by vapor pressure and heating rates.