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        검색결과 164

        81.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 초소수성 실리카 에어로겔을 이용하여 단열 성능을 갖는 투명 필름용 유/무기 복합 코팅물질을 제조하였다. 바인더 물질로 사용된 자외선 경화형 우레탄 아크릴레이트 수지와 에어로겔과의 상용성을 위해 계면활성제(Brij 56)를 이용하여 에어로겔의 표면을 개질하였다. 개질된 에어로겔을 고분자 수지와 복합화한 코팅 용액을 폴리카보네이트 기지재에 코팅한 후 자외선경화를 통해 코팅필름을 제조하였다. 에어로겔이 10 vol% 함량으로 첨가되었을 때, 코팅필름의 단열성능은 측정된 열전도도 기준으로 순수 기지재 대비 28% 정도로 향상되었다. 또한, 코팅필름의 광투과율은 에어로겔이 50 vol%로 과량 첨가된 경우에도 80% 이상 높은 수준을 유지하였으며, 우수한 접착성(5B) 및 연필 경도(4H)를 보여주었다.
        4,000원
        82.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate the physicochemical properties of mung bean starch and the texture of cold-stored (5℃ for 0, 24, 48, and 72 hours) mung bean starch gels added with soy bean oil (0, 2, 4, 6%). The swelling power of mung bean starch added with soy bean oil did not significantly change, whereas solubility increased significantly. Soluble carbohydrate content of mung bean starch added with soy bean oil decreased without any significant differences, whereas soluble amylose content decreased significantly. In RVA viscosity, pasting temperature and peak viscosity of mung bean starch added with soy bean oil were not significantly different, whereas minimum viscosity decreased and breakdown and consistency increased significantly. In RVA viscosity, there were no differences according to concentration of soy bean oil. DSC thermograms show that onset temperature of mung bean starch added with soy bean oil did not significantly change, whereas the enthalpy increased in the case of 4% and 6% oil addition. Rupture properties of freshly prepared mung bean starch gels added with soy bean oil increased in the case of 2% and 4% oil addition, and oil addition to mung bean starch gels suppressed changes in rupture properties during cold storage. There were no significant differences in the texture of freshly prepared mung bean starch gels added with soy bean oil, whereas hardness, chewiness, and gumminess of cold-stored mung bean starch gels added with soy bean oil decreased. In the above textural charactristics, there were no differences due to concentration of soy bean oil. Thus, the addition of 2-4% soy bean oil to mung bean starch is appropriate for improving the quality characteristics of cold-stored mung bean starch gels.
        4,000원
        84.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon nanotube(CNT) plays an essential role in various fields of nano based science and technology. Recently, silica coated CNT composites are interested because they are useful for the optical, magnetical, and catalytic applications. In this report, carboxyl groups were introduced on the MWCNT using nitric acid. In order to maximize the silica encapsulation efficiency, carboxyl groups of MWCNT reacted with a silane coupling agent were used to prepare silica coated MWCNT. Due to their strong interaction between modified MWCNT and TEOS. Silica layer with a controllable thickness was achieved. Silica coated MWCNT were further utilized as the template for the synthesis of hollow silica nanotubes after 800℃ calcination.
        4,200원
        85.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The synthesis behavior of nanoporous silica aerogel in the macroporous ceramic structure was observed using TEOS as a source material and glycerol as a dry control chemical additive (DCCA). Silica aerogel in the macroporous ceramic structure was synthesized via sono-gel process using hexamethyldiazane (HMDS) as a modification agent and n-hexane as a main solvent. The wet gel with a modified surface was dried at under ambient pressure. The addition of glycerol appears to give the wet gel a more homogeneous microstructure. However, glycerol also retarded the rate of surface modification and solvent exchange. Silica aerogel completely filled the macroporous ceramic structure without defect in the condition of surface modification (20% HMDS/nhexane at 36hr).
        4,000원
        87.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        New biological treatments were being developed at a record place, but their potential could be compromised by a significant obstacle: the delivery of these drugs into a body. Pharmaceutical delivery is now nearly as important as product. New systems are being developed, and Drug Delivery Markets Series cover these new systems. Transdermal Delivery System(TDS) is often used as a method of drug dosage into the epidermic skin. An approach used to delivery drugs through the skin for therapeutic use as an alternative to oral, intravascular, subcutaneous and transmucosal routes. Various transdermal drug delivery technologies are described including the use of suitable formulations, carriers and penetration enhancers. The most commonly used transdermal system is the skin patch using various types of technologies. Compared with other methods of dosage, it is possible to use for a long term. It is also possible to stop the drug dosage are stopped if the drug dosage lead to side effect. Polysaccharides, such as karaya gum and glucomannan, were selected as base materials of TDS. Also, these polymers were characterized in terms of enhancers, drug contents. Among these polysaccharide, the permeation rate of karaya gum matrix was fastest in fibric acid(ciprofibrate) such as lipophilic drug in vitro. We used glycerin, PEG400 and PEG800 as enhancers. Since dermis has more water content(hydration) than the stratum corneum, skin permeation rate at steady state was highly influenced when PEG400 was more effective for lipophilic drug. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate. Especially, this result suggests a possible use of polysaccharide gel ointment matrix as a transdermal delivery system of anti-hyperlipoproteinemic agent.
        4,000원
        89.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In preparation of silica aerogel-based hybrid coating materials, the combination of hydrophobic aerogel with organic polar binder material is shown to be very limited due to dissimilar surface property between two materials. Accordingly, the surface modification of the aerogel would be required to obtain compatibilized hybrid coating sols with homogeneous dispersion. In this study, the surface of silica aerogel particles was modified by using both surfactant adsorption and heat treatment methods. Four types of surfactants with different molecular weights and HLB values were used to examine the effect of chain length and hydrophilicity. The surface property of the modified aerogel was evaluated in terms of visible observation for aerogel dispersion in water, water contact angle measurement, and FT-IR analysis. In surface modification using surfactants, the effects of surfactant type and content, and mixing time as process parameter on the degree of hydrophilicity for the modified aerogel. In addition, the temperature condition in modification process via heat treatment was revealed to be significant factor to prepare aerogel with highly hydrophilic property.
        4,000원
        90.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        다공성 Poly(propylene) 분리막의 지지 하에 전해질 용액 (EC/DEC 1 : 1 혼합물 내의 LiPF6 1 M 용액) 내에서 DEGDMA [Di(ethylene glycol) dimethacrylate]의 70℃ 열중합을 통하여 겔 고분자 전해질(GPE)막이 합성 되었다. 합성된 겔 고분자 전해질막의 이온전도도 및 전기화학적 안정성은 AC 임피던스법 및 CV (cyclic voltametry)법에 의하여 측정 평가하였다. 겔 고분자를 전해질로, 그리고 양극 및 음극으로는 각각 LiMi0.8Co0.2O2 및 graphite로 이용하여 리튬이온전지(LIB)도 제작하였다. 열중합을 통하여 리튬 이온전지에 적합한 이온전도도(10 -3 S/cm 이상) 및 전기화학적 안정성을 보이면서 자체적인 성상을 유지하는 겔 고분자 전해질막을 얻을 수 있었다. 단량체 함량 5%의 전구체로 제작한 겔 고분자 전지는 단량체 함량이 7.0% 및 10.0%인 경우에 비하여 우수한 고율 및 충-방전 효율을 보였다.
        4,000원
        91.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: In vitro 조건 하에서 재질이 다른 실리콘 하이드로겔 렌즈에 결합되는 눈물의 지방성분인 올레산(oleic acid), 올레산에스테르(oleic acid methyl ester) 및 콜레스테롤(cholesterol)을 각각 정량하여 실리콘 하이드로겔렌즈에 부착되는 지방침전물을 비교하였다. 방법: Lotrafilcon A, lotrafilcon B, galyficon A 및 balafilcon A 재질의 실리콘 하이드로겔 렌즈와polymacon 렌즈 및 RGP 렌즈를 올레산, 올레산에스테르 및 콜레스테롤을 동일한 양 포함하는 식염수 용액에 담가 37℃에서 흔들어주면서 24시간 동안 오염시킨 후, methanol과 chloroform을 1:1(v/v) 비율로 포함하는 유기용매를 이용하여 4시간 동안 렌즈에 부착된 지방을 추출하였다. 추출된 지방은 C-18 column을 사용하여 HPLC(high performance liquid chromatography)를 수행하여 분리하고 정량하였다. 결과: 실리콘 하이드로겔렌즈에 부착된 지방의 총량은 재질의 종류에 따라 48~67 ㎍/lens, polymacon 렌즈와 RGP 렌즈에서는 각각 18 ㎍/lens, 177 ㎍/lens로 측정되어, 실리콘 하이드로겔렌즈의 지방 부착량은 polymacon 소프트렌즈의 300~372%, RGP 렌즈의 30.5~37.8%로 나타났다. 지방침전물은 galyfilcon A 재질에 가장 많이 부착되었으며(p
        4,300원
        92.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        세공 크기가 2.6 μm인 SPG (Shirasu porous glass) 막이 설치된 실험실 규모의 막유화 장치를 사용하여 막유화 에멀젼-겔 공정의 변수 조절을 통해 구형상의 실리카 입자를 제조하였다. 막유화 에멀젼-겔 공정의 변수로는 분산상 압력, 연속상 내 안정제 및 유화제의 농도, H2O/TEOS 비율 및 연속상에 대한 분산상의 비율로 설정하고, 이들 변수가 제조된 실리카 입자의 크기와 분포에 미치는 영향을 검토하였다. 막유화의 공정변수들 중에서 분산상 압력과 연속상에 대한 분산상의 비가 증가할수록 실리카 입자의 크기가 증가하였다. 반면 안정제 및 유화제의 농도, H2O/TEOS 비가 증가할수록 입자의 크기가 감소하였다. 막유화 에멀젼-겔 공정변수의 조절을 통해 최종적으로 평균 입자 크기가 3 μm인 비교적 입도분포가 균일한 구형상의 실리카 입자 제조가 가능하였다.
        4,000원
        93.
        2010.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The fibrous material fraction as a by-product from the commercial aloe vera gel processing was obtained and freeze dried. The physicochemical characteristics such as the proximate composition, crystalline/surface structures and several physical functionalities including the water holding capacity (WHC), swelling capacity (SW), oil holding capacity (OHC), emulsion/foam properties and viscosity properties of this powdered sample (100 mesh) were investigated and analyzed by comparison with commercial α-cellulose as a reference sample. The total dietary fiber content of powdered sample was very high as much as 87.5%, and the insoluble dietary and soluble dietary fiber content ratios were 77.6 and 22.4%, respectively. The FT-IR spectrum of powdered sample showed a typical polysaccharide property and exhibited a x-ray diffraction pattern for cellulose III and IV like structure. SW (8.24±0.15 mL/g), WHC(6.40±0.19 g water/g solid) and OHC(10.32±0.29 g oil/g solid) of freeze dried aloe cellulose were about 3.3, 1.4 and 2 times higher than those of commercial α-cellulose, respectively. Aloe cellulose (~2%, w/v) alone had no foam capacity while improved the foam stability of protein solution (1% albumin+0.5% CaCl2) by factor of 300%. Emulsion capacity of 2%(w/v) aloe cellulose was about 70% level of 0.5%(w/v) xanthan gum, but its emulsion stability was about 1.2 times higher than that of xanthan gum. Also, aloe cellulose containing CMC (carboxyl methyl cellulose) of 0.3%(w/v) showed a very good dispersity. Aloe cellulose dispersion of above 1%(w/v) exhibited higher pseudoplasticity and concentration dependence than those of α-cellulose dispersion, indicating the viscosity properties for new potential usage such as an excellent thickening agent.
        4,000원
        95.
        2009.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In vitro physiological functions such as jack bean (Canavalia ensiformis) urease inhibitory activity and retarding effect of glucose/bile acid of Aloe vera gel concentrated by the optimized DIS (Dewatering Impregnation & Soaking) process conditions were examined. Urease inhibitory activity of DIS aloes ranged from 84.6 to 94.4%, which was similar to or higher than 86.3% of fresh aloe. Also, urease inhibitory activity of DIS aloes was maintained at initial levels after heat treatment (90oC, 10 min.) and drying treatment (freeze or hot air drying). Urease inhibition pattern from Lineweaver-Burk plot indicated general non-competitive inhibition, and inhibition constants (KIE and KIES) of DIS aloes were 41-149 and 87-163 μL/mL, respectively. DIS(glucose) and DIS (polyethylene glycol) exhibited the highest retarding effect of glucose and bile acid. Their retarding effects were about 1.6 and 1.8 folds higher than that of fresh aloe after 0.5 and 1 hr of the dialysis, respectively. Conclusively, the above in vitro physiological functions of Aloe vera gel concentrated by DIS process suggested that aloe products treated with DIS would have the potential benefits for protection against Helicobacter pylori and reduction of blood glucose and cholesterol levels.
        4,200원
        96.
        2009.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the quality characteristics of mungbean starch gels containing various hydrocolloids (carrageenan, locust bean gum and xanthan gum) during room temperature storage (25℃ for 24, 48 and 72 hours). Carrageenan and xanthan gum reduced the pasting viscosity of mungbean starch, whereas the locust bean gum increased the viscosity. The melting characteristics, as assessed by DSC, showed that carrageenan and xanthan gum delayed gelatinization of mungbean starch and the locust bean gum had no effect on this property. The lightness (L) of the gels with the locust bean gum was similar to that without the additive during storage, whereas that with carrageenan and xanthan gum was higher than that without the additive. Hardness, chewiness and gumminess of the gels with the locust bean gum was higher than that without the additive during storage, whereas that with carrageenan and xanthan gum was lower than that without the additive. The rupture stress, rupture strain and rupture energy of the gels with carrageenan and xanthan gum was lower than that without the additive during storage, whereas that with the locust bean gum was similar to that without the additive. In the sensory evaluation, springiness and cohesiveness of the gels with carrageenan and xanthan gum were lower than those without the additive, whereas springiness, brittleness and hardness of the gels with the locust bean gum were higher than those without the additive. In addition, the overall acceptability of the gels with the locust bean gum improved. The above results showed that carrageenan and xanthan gum lowered the quality characteristics of the mungbean starch gel and the locust bean gum improved them. Thus, the addition of 0.5% locust bean gum is an appropriate method for improving the quality characteristics of mungbean starch gel.
        4,300원
        97.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polymer gel implant for soft tissue augment is demanded biological safety properties. This study is designed process and equipment producing for obtain micro bead using the hyaluronic acid water solution. This equipment is composed of cooling pipe, air pump, dispenser and process is consecutive/simple for preservation from environmental contamination. Besides, without difficulty remove the residual agent after crosslink. We evaluate to in vitro cytotoxicity test for verification of hyaluronic acid gel obtained by this equipment and process. This product is "non cytotoxcity" from the result of evaluation cytotoxcity test.
        4,000원
        98.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        세공경 1.5μm인 SPG (Shirasu porous glass) 막이 설치된 실험실 규모의 막유화 장치를 사용하여 구(球) 형상의 단분산 실리카 마이크로겔을 제조하기 위한 막유화 공정변수의 최적조건을 결정하였다. 막유화의 공정변수로는 분산상 내규산소다의 농도, 분산상 압력, 연속상에 대한 분산상의 비율, 연속상 내 유화제의 농도, 연속상의 교반속도로 설정하고, 이들 변수가 제조된 실리카 마이크로겔의 입자 크기와 분포에 미치는 영향을 검토하였다. 막유화의 공정변수들 중에서 연속상에 대한 분산상의 비율, 분산상 압력 및 분산상 내 규산소다의 농도가 증가할수록 겔 입자의 크기가 증가하였다. 반면 유화제의 농도와 연속상의 교반속도가 증가할수록 겔 입자의 크기가 감소하였다. 막유화의 공정변수 조절을 통해 최종적으로 평균 입자 크기가 6 μm인 입도분포가 균일한 구 형상의 실리카 마이크로겔을 제조할 수 있었다.
        4,000원
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