• 폴리머
• /
• 제25권4호
• /
• pp.528-535
• /
• 2001

본 연구에서는 polyol, MDI, 실리콘 유화제, 물을 기본 폴리우레탄 조성으로 설정하였으며, 경질 폴리우레탄 폼에 있어서 sitff-chain 요소인 에틸렌 글리콜의 첨가에 의하여 가교밀도가 증가하며, 이에 따른 셀의 크기, 발포 배율, cream time, gel time, take free time의 변화, 최종 자유 발포체 높이, 반응 온도, 단열도 변화를 관찰하였다. 발포제는 시클로펜탄을 사용하여 경질 물리우레탄을 발포하였으며, 상온, 상압에서 hand mixing 으로 5000 rpm, 4sec의 범위 안에서 혼합시킨 뒤에, 에틸렌 글리콜의 양을 변화시켜 200 ${\times}$ 200 ${\times}$ 200 mm 내의 나무 금형 안에서 발포 실험하였다. 이소시아네이트 인덱스를 고정시켰을 경우 에틸렌글리콜의 양이 증가함에 따라 셀의 크기는 약 5.1%와 열전도는 약 14%가 감소하였다.

• Korean Membrane Journal
• /
• 제6권1호
• /
• pp.44-54
• /
• 2004

Organic-inorganic composite membranes based on sulfonated poly(phthalazinone ether sulfone) (sPPES)/silica hybrid were prepared using the sol-gel process under acidic conditions. The sulfonation of PPES with concentrated sulfuric acid as sulfonation agent was carried out to prepare proton exchange membrane material. The behaviors of the proton conductivity and methanol permeability are depended on the sulfonation time (5-100 hr). The hybrid membranes composed of highly sulfonated PPES (IEC value: 1.42 meq./g) and silica were fabricated from different silica content (5-20 wt%) in order to achieve desirable proton conductivity and methanol permeability demanded for fuel cell applications. The silica particles within membranes were used for the purpose of blocking excessive methanol cross-over and for forming the path way to transport of the proton due to absorbing water molecules with ≡SiOH on silica. The presence of silica particles in the organic polymer matrix results in hybrid membranes with reduced methanol permeability and improved proton conductivity.

• Korean Chemical Engineering Research
• /
• 제53권3호
• /
• pp.382-390
• /
• 2015

Poly(methyl methacrylate) (PMMA) supports and amine additives were investigated to adsorb $CO_2$. PMMA supports were fabricated by using different ratio of pore forming agents (porogen) to control the BET specific surface area, pore volume and distribution. Toluene and xylene are used for porogens. Supported amine sorbents were prepared by wet impregnation of tetraethylenepentamine (TEPA) on PMMA supports. So we could identify the effect of the pore structure of supports and the quantity of impregnated TEPA on the adsorption capacity. The increased amount of toluene as pore foaming agent resulted in the decreased average pore diameter and the increased BET surface area. Polymer supports with huge different pore distribution could be fabricated by controlling the ratio of porogen. After impregnation, the support with micropore structure is supposed the pore blocking and filling effect so that it has low $CO_2$ capacity and kinetics due to the difficulty of diffusing. Macropore structure indicates fast adsorption capacity and low influence of amine loading. In case of support with mesopore, it has high performance of adsorption capacity and kinetics. So high surface area and meso-/macro- pore structure is suitable for $CO_2$ capture.

• 한국식물학회:학술대회논문집
• /
• 한국식물학회 1987년도 식물생명공학 심포지움 논문집 Proceedings of Symposia on Plant Biotechnology
• /
• pp.157-167
• /
• 1987

The have been many reports that phenoloxidase are correlated with development in many fungi. C. congregatus, one of nushroom-forming basidiomycetes, which requires light for its development also has phenoloxidases. In C. congragatus, there are two sets of membrane-associated phenoloxidase (PHO I and PHO II) which are differentiated by their isozyme patterns, and each enzyme set consists of two different subtrate specific enzyme protein; o-tolidine reacting enzyme, and DOPA reacting enzyme. PHO I which is localized by a protoplast-concanavalin A technique by using a new solidifying agent, Pluronic Polyol F 127, instead of agar appears in the vegetative hyphae, and PHO II appears at the early primordial stage on agar and at the sclerotial stage of liquid shake cultures. Inhibition of PHO I with the enzyme inhibitors inhibits mushroom formation as well as melanization of the vegetative hyphae at concentrations which do not inhibit the vegetative growth. PHO I deficient mutants do not form mushrooms or melanins, and the mutants show abnormal nuclear migration patterns. PHO II has roles; possibly cementing the adjacent hyphae during the actual three dimensonal structure formation, and melanizing mushrooms and sclerotia. The possible roles of PHO I in the light reception complex and in melanin formation, the function of malanin, and possible roles of postulated post translational modifying enzymes which regulate the phenoloxidases, nuclear migration pattern, and self-nonself recognition mechanism are discussed.

• Journal of Korean Biological Nursing Science
• /
• 제8권2호
• /
• pp.41-59
• /
• 2006

Chronic liver diseases and hepatic cancer have been reported as 10% of cause of death in Koreans. Regardless of various causes, chronic liver disease accompanies commonly hepatic fibrosis. But still the mechanism of hepatic fibrosis remains poorly understood. Using the dimethylnitrosamine(DMN)-induced hepatic fibrosis rat model, We performed to evaluate the possible therapeutic effect of RIP(extracts of Phellodendron amurense and Patrinia scabiosaefolia) and to investigate the changes in referential connective tissue proteins($TGF-{\beta}_1$, ${\alpha}$-smooth muscle actin, and vimentin) as a marker of fibrogenesis. For these purposes, liver tissues were stained with H & E, and Azan staining for estimation of developing fibrosis. In the DMN-treated rat liver tissue, fibrosis were developed forming incomplete septal fibrosis. Whereas, in the RIP-treated rat liver tissues, the fibrosis were decreased recovering to normal morphology. The expressions of $TGF-{\beta}_1$, ${\alpha}$-smooth muscle actin($\alpha-SMA$), and vimetin were increased in the DMN-treated rat liver tissues, but decreased in the various areas of RIP-treated rat liver tissues. According to these results, RIP could be a possible therapeutic agent to reduce hepatic fibrosis, and the $TGF-{\beta}_1$, ${\alpha}$-SMA, and vimentin could be possible indicative markers of hepatic fibrosis development and recovery.

• The Plant Pathology Journal
• /
• 제27권1호
• /
• pp.85-88
• /
• 2011

Podosphaera fusca (syn. Sphaerotheca fusca, S. fuliginea) is a causal agent of powdery mildew infections on Zinnia elegans, and has been documented in Korea since 1967. An outbreak involving about 1,000 plants in October 2008, in Yangpyeong, Korea, was caused by Golovinomyces cichoracearum. Further surveys of zinnia powdery mildew from 2008-2010 confirmed the widespread occurrence of Zinnia-Golovinomyces association in Korea. Chasmothecia of this fungus have not been found on Z. elegans in Korea. Analysis of internal transcribed spacer rDNA from five Korean collections confirmed the powdery mildew as G. cichoracearum. Comparison with the those from GenBank revealed 100% identity with sequences from zinnia powdery mildew, forming a monophyletic clade with 100% bootstrap support, and with those of G. cichoracearum parasitic on the hosts belonging to the tribe Heliantheae of the family Asteraceae.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1998년도 추계 총회 및 학술발표회
• /
• pp.87-90
• /
• 1998

1. 서론 : 막 분리공정에 사용되고 있는 대부분의 고분자 막들은 침지침강(immersion precipitation) 상변환법에 의해 제조되고 있다. 침지침강 상변환법으로 제조된 막의 최종 구조는 고분자 캐스팅 용액의 열역학적 특성과 비용매와의 속도론적 특성에 따라 대칭형 또는 비대칭형 막구조를 갖게 된다. 고분자/용매로 이루어진 캐스팅 용액에 제3의 성분으로서 PVP, PEG, LiCl. ZnCl$_2$ 와 같은 유.무기물을 첨가시킴으로서 막구조 및 투과성능을 변화시킬 수 있다. 이러한 점에서 이들 첨가제를 pore-forming agent라 부르기도 한다. 본 연구에서는 상대적으로 열적.기계적 특성이 우수하고, 화학약품에 대한 안정성이 뛰어나 상변환 막의 소재물질로서 널리 사용되고 있는 Polyethersulfone(PES)을 막 소재 물질로 사용하여 PES/NMP 캐스팅 용액에 다양한 종류의 무기염[CaCl$_2$, LiCl, LiClO$_4$, Mg(ClO$_4)_2$, ZnCl$_2$]을 PES에 대한 중량비를 달리하여 첨가시켜 비대칭 막을 제조하여 무기염의 첨가가 막구조 형성 및 막투과 특성에 미치는 영향을 연구하였다. 이때 첨가된 무기염 및 첨가 중량비에 따른 영향을 PES/NMP/Salt 계의 coagulation value, light transmittance, 점도 등의 열역학 및 속도론적 특성으로서 설명하였다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2006년도 하계학술발표대회 논문집
• /
• pp.150-155
• /
• 2006

Falling liquid plays a role in a wide variety of naturally occurring phenomena as well as in the operation of industrial process equipment where heat and mass transfer take place. In such cases, it is required that the falling film should spread widely on the surface forming thin liquid film to enlarge contact surface. An addition of surface active agent to a falling liquid film affects the flow characteristics of the falling film. In this study the heat transfer characteristics for a falling liquid film has been investigated by an addition of the surface active agents. The falling liquid film was formed on a vertical flat plate. As the mass flow rate of liquid falling film is increased, the wetted area is a little increased while the heat transfer rate as well as heat transfer coefficient is significantly increased. It is also found that both wetted area and heat transfer rate is substantially increased while heat transfer coefficient is a little increased with an increase in the surfactant concentration at a given mass flow rate.

• 설비공학논문집
• /
• 제18권11호
• /
• pp.867-873
• /
• 2006

Vertical falling liquid film is extensively used in heat and mass transfer processes of many applications, such as evaporative coolers, cooling towers, and absorption chillers. In such cases, it is required that the falling film spreads widely in the surface forming thin liquid film to enlarge contact surface. An addition of surface active agent to a falling liquid film or hydrophilic surface treatment affects the fluid physical properties of the film. Surfactant addition not only decreases contact angle between the liquid and solid surface but also changes the surface from hydrophobicity to hydrophilicity. In this study, the effects of contact angle on falling film characteristics over a vertical surface have been investigated experimentally. The contact angle is varied either by an addition of surfactant to the liquid or by hydrophilic surface treatment. It is found that the wetted area is increased and film thickness is decreased by the hydrophilic treatment as compared with those of other surfaces. With this hydrophilic treatment, the falling liquid film spreads out widely in the surface. As surfactant concentration is increased, wetted area is also increased and the film thickness is substantially decreased.

• Nuclear Engineering and Technology
• /
• 제15권2호
• /
• pp.117-122
• /
• 1983

$\beta$-diketo의 관능기를 가진 1-phenyl-3-methyl-4-acyl-pyrazolone-5-one (acyl pyrazolone)이라고 이름지어진 킬레이팅 화합물은 오랫동안 동위원소 분리 및 추출에 이용되어 왔다. 새로운 acylating 물질을 사용해서 만들어진 succinyl, malenyl 그리고 phthalyl pyrazolone이 우라늄이온(VI)과 고가의 산화상태를 지니는 다른 중금속의 추출에 이용되었다. Succinyl pyrazolone이 우라늄(VI) 추출에서 매우 뛰어나다는 것이 밝혀졌으며, 대체로 카르복실 관능기를 가진 킬레이팅 화합물이 우라늄(VI) 혹은 악티나이드 계열의 중금속 추출에 매우 효과적인 것으로 나타났다.