검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 253

        81.
        2014.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of ginkgo nut powder on the antioxidant activity and quality characteristics of mung bean starch gel. Mung bean starch gels were prepared with different amounts of ginkgo nut powder (0, 1, 3, 5, and 7%). The antioxidant activity of ginkgo nut powder and mung bean starch gel was estimated through measuring DPPH free radical scavenging activity and total phenolic acid content. For analyzing quality characteristics several factors were considered: syneresis, pH, color, texture profile analysis, and sensory evaluations. In the results, syneresis in the treated group was higher than the control group. The pH, b values, total phenolic acid content, and DPPH free radical scavenging activity of mung bean starch gels also significantly increased with increasing ginkgo nut powder. In contrast, the L values and a values of mung bean starch gels significantly decreased with increasing ginkgo nut powder. In the texture profile analysis, the mung bean starch gels with 5% and 7% ginkgo nut powder showed significantly lower degrees of hardness, chewiness, and gumminess. On the other hand, cohesiveness was highest in the mung bean starch gels with 5% and 7% ginkgo nut powder. The consumer acceptability score for the mung bean starch gel prepared with 5% and 7% ginkgo nut powder ranked significantly higher than the other groups in flavor and taste. Overall, these results suggest that ginkgo nut powder is a good ingredient for increasing the consumer acceptability and functionality of mung bean starch gel.
        4,000원
        82.
        2014.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Mg-enriched magnesium aluminum silicate (MAS) glass is known for its higher mechanical strength and chemical resistance. Among such glasses, cordierite (Mg2Al4Si5O18) is well known to have a low thermal expansion and low melting point. Polycrystalline engineering ceramics such as alumina can be strengthened by a surface modification with low thermal expansion materials. The present study involves the synthesis of cordierite by a sol-gel process and investigates the effect of glass penetration on the surface of alumina. The cordierite powders were prepared from Al(OC3H7)3, Mg(OC2H5)2 and tetraethyl orthosilicate by hydrolysis and condensation reaction. The cordierite powders were characterized by X-ray diffraction (XRD, Rigaku), scanning electron microscope (SEM, JEOL: JSM-5610), energy dispersive spectroscopy (EDS, JEOL: JSM-5610), and universal testing machine (UTM, INSTRON). The X-ray diffraction patterns showed that the synthesized particles were μ-cordierite calcined at 1100˚C for 1 h. The shape of synthesized cordierite was changed from μ-cordierite to α-cordierite with increasing calcination temperature. Synthesized cordierite was used for surface modification of alumina. Cordierite powders penetrated deeply into the alumina sample along grain boundaries with increasing temperature. The results of surface modification tests showed that the strength of the prepared alumina sample increased after surface modification. The strength of a surface modified with synthesized cordierite increased the most, to about 134.6MPa.
        4,000원
        83.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanocomposites comprised of graphene oxide (GO) nanosheets and magnesium oxide (MgO) nanoparticles were synthesized by a sol-gel process. The synthesized samples were studied by X-ray powder diffraction, atomic force microscopy, transmission electron microscopy, and energy-dispersive X-ray analysis. The results show that the MgO nanoparticles, with an average diameter of 70 nm, are decorated uniformly on the surface of the GOs. By controlling the concentration of the MgO precursors and reaction cycles, it was possible to control the loading density and the size of the resulting MgO particles. Because the MgO particles are robustly anchored on the GO structure, the MgO/GOs nanocomposites will have future applications in the fields of adsorption and chemical sensing.
        3,000원
        84.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 여러 가지 생리활성을 가지고 있다고 알려 진 감을 활용하고자 감 분말을 0~9% 첨가한 청포묵을 제조 하여 감 묵의 항산화 활성 및 품질특성을 측정하였다. 감 분 말을 청포묵에 첨가한 경우, 시료의 첨가량에 비례하여 총 페 놀 화합물의 함량이 증가하였으며, DPPH 라디칼 소거능 또 한 감 분말의 첨가량에 따라 그 활성이 유의적으로 증가하는 결과를 나타내었다. 항산화 활성의 기능성과 함께 제품의 적 합성 판단을 위해 감 묵의 품질평가를 실시한 결과, 감 묵의 이수율은 대조군에 비해 감 분말 1~7% 첨가 묵의 이수율이 낮게 나타났으며, 감 분말 9% 첨가군은 대조군보다 높게 나 타났다. 감 묵의 pH는 감 분말 첨가량에 비례하여 증가하였 으며, 색도는 감 분말 첨가량이 증가할수록 L값과 a값이 낮아지고, b값이 높아지는 유의적인 차이를 나타냈다. 감 묵의 조 직감 측정 결과 견고성과 탄력성은 유의적인 차이가 없었으 며, 부착성은 7% 첨가군에서 가장 높게 나타났다. 씹힘성 및 검성에서는 9% 첨가군이 가장 낮은 수치를 나타내었고, 응집 성의 경우 시료 첨가량이 증가할수록 낮은 응집성을 보여주 었다. 감 묵의 기호도 검사에서 전반적인 기호도, 외관, 향, 색 등 대부분의 항목에서 감 분말 7% 첨가군이 높은 점수를 받았고, 특성 강도 검사에서는 투명도와 탄력성에서는 유의 적인 차이가 없었으며 단맛은 7%와 9% 첨가군이 유의적으 로 가장 강하다는 결과를 얻었다. 이러한 결과로 보아 감 분 말을 청포묵에 첨가하는 것은 감 묵의 항산화 활성과 기호도 를 증가시켜 청포묵의 가치를 높일 수 있을 것으로 사료되며, 청포묵 제조 시 항산화능이 높고, 기호도가 가장 좋았던 7% 감 분말을 첨가하는 것이 바람직할 것으로 생각된다.
        4,000원
        85.
        2013.11 KCI 등재 구독 인증기관·개인회원 무료
        귀리, 콩, 감자, 밀에서 유래한 다양한 식이섬유를 밀가루 대신 10-40%까지 대체함에 따른 수화능, 동적점탄성, 용매흡착능 및 in vitro starch digestion을 비교하였다. 귀리, 콩, 감자, 밀에서 유래한 다양한 식이섬유를 식이섬유의 대체비율이 증가할수록 수분흡착능과 팽윤력은 증가한 반면, 수분용해도는 감소하였다. 밀가루 대신 콩과 감자 식이섬유를 대체함에 따라 동적점탄성은 증가하였으나, 귀리와 밀 식이섬유 대체에서는 오히려 감소하는 경향을 보였다. 식이섬유 대체에 따른 밀가루의 용매흡착능 변화를 분석한 결과, 낮은 대체량의 귀리 식이섬유와 높은 대체량의 콩과 감자 식이섬유가 활용 가능성을 보였다. 원료별 식이섬유 대체 시 밀가루 겔의 전분소화 패턴은 식이섬유 대체비율이 증가함에 따라 glucose 방출은 감소하였으나, 원료별 특성에 따른 유의적인 차이는 없었다. 특히, 밀식이섬유를 제외한 귀리, 콩, 감자 식이섬유는 모두 RDS감소와 RS증가에 따른 pGI 저하를 보여 실제 식품소재로 활용 시 가공적성을 유지할 수 있다면 전분소화지연효과를 기대할 수 있음을 확인할 수 있었다. 한편, 식이섬유의 원료에 따른 식이섬유 조성과 전분소화 관련 특성 간 상관관계를 분석한 결과, 전분소화를 지연시키는 효과는 수용성 식이섬유보다는 불용성과 총식이섬유 함량이 중요한 인자임을 알 수 있었다.
        86.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two fractions (permeate and retentate) from fiber free Aloe vera gel were prepared using an ultra-filtration (UF) system with a tubular ceramic membrane (MWCO of 50 kDa), and their dilute solution properties were investigated. The intrinsic viscosities of fiber free Aloe vera gel and the retentate and permeate fractions that were prepared by ultra-filtration were 18.48, 37.74, and 2.01 dL/g, respectively. UF aloe retentate as a polysaccharide rich fraction exhibited polyelectrolyte behavior showing a sharp decrease of intrinsic viscosity by the addition of NaCl. However, as its NaCl concentration increasing to 1 M, its intrinsic viscosity slightly increased due to conformational change caused by the high concentration of NaCl. On the one hand, the intrinsic viscosities of the dilute UF-retentate solution were exponentially decreased with increasing temperature, and the temperature dependency of its intrinsic viscosity showed a sharp discontinuity at 30oC instead of a linear Arrhenius behaviour, indicating a variation of flow mechanism or network rearrangement of a molecular chain. The chain stiffness of polysaccharide rich fraction at bellow and above 0.5 M of NaCl addition was 0.048 and 0.515, respectively, showing different stiffenings and significant conformational change. The coil overlap parameter and critical concentration of UF-retentate were 3.0 and 0.08 g/dL, respectively.
        4,000원
        87.
        2013.10 구독 인증기관·개인회원 무료
        Most traditional genome sequencing projects involving infectious viruses include culturing and purification of the virus. This can present difficulties as an analysis of multiple populations from multiple locations may be required to acquire sufficient amount of high-quality DNA for sequence analysis. The electrophoretic method provides a strategy whereby the genomic DNA sequences of the Korean isolate of Pieris rapae granulovirus (PiraGV-K) were analyzed by purifying it from host DNA by pulsed-field gel electrophoresis, thus simplifying sampling and labor time. The genomic DNA of infected P. rapae was embedded in agarose plugs, digested with a restriction nuclease and methylase, and pulsed-field gel electrophoresis (PFGE) was used to separate PiraGV-K DNA from the DNA of P. rapae, followed by mapping of fosmid clones of the separated viral DNA. The double-stranded circular genome of PiraGV-K encodes 120 open reading frames (ORFs), covering 92% of the sequenced genome. BLAST and ORF arrangement showed the presence of 78 homologs to other genes in the database. The mean overall amino acid identity of PiraGV-K ORFs was highest with the Chinese isolate of PiraGV (~99%), followed up with Choristoneura occidentalis ORFs at 58%. PiraGV-K ORFs were grouped, according to function, into 10 genes involved in transcription, 11 involved in replication, 25 structural protein genes, and 15 auxiliary genes. Genes for Chitinase (ORF 10) and cathepsin (ORF11), involved in the liquefaction of the host, were found in the genome. The recovery of PiraGV-K DNA genome by pulse-field electrophoretic separation from host genomic DNA had several advantages, compared with its isolation from particles harvested as virions or inclusions from the P. rapae host. We have sequenced and analyzed the 108,658 bp PiraGV-K genome purified by the pulsed field electrophoretic method. The method appears to be applicable to the analysis of genomes of large viruses. The chitinase, identified by PiraGV-K genome sequence, was functionally characterized by quantitative PCR, Western blot analysis, immunohistochemistry and transmission electron microscopy.
        88.
        2013.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        There is increasing interest in zirconia as a dental material due to its aesthetics, as well as the exceptionally high fracture toughness and high strength that are on offer when it is alloyed with certain oxides like yttria. In recent years, many solution based chemical synthesis methods have been reported for synthesis of zirconia, of which the sol-gel method is considered to be best. Here, we synthesize zirconia by a sol gel assisted precipitation method using either PEG or PVA as a stabilizing agent. Zirconia sol is first synthesized using the hydrothermal method. We used NaOH as the precipitating agent in this method because it is easy to remove from the final solution. Zirconium and yttrium salts are used as precursors and PEG or PVA are used as stabilizers to separate the metal ions. The resulting amorphous zirconia powder is calcined at 900˚C for 2 h to get crystallized zirconia. XRD analysis confirmed the partially stabilized zirconia synthesis in all the synthesized powders. SEM was taken to check the morphology of the powder synthesized using either PEG or PVA as a stabilizing agent and finally the transparency was calculated. The results confirmed that the powder synthesized with 10 % PVA as the stabilizing agent had highest percentage of transparency among all the synthesized powder.
        4,000원
        89.
        2013.06 구독 인증기관 무료, 개인회원 유료
        Nuts are one of the most common sources of allergies in individuals of all ages. In order for a particular protein to render an allergic reaction, it must resist proteolytic digestion by intestinal enzymes. In this study, three well-known allergenic nuts, almonds, cashew nuts, and peanuts, were used as samples, and enzyme digestion with Bacillus protease and porcine pepsin was tested. A proteomic approach using two-dimensional gel electrophoresis and an MS/MS analysis was applied to visualize and identify the proteins that were resistant to enzyme digestion. Among the 150 protein spots tested, 42 proteins were assigned functions. Due to the lack of genomic databases, 41% of the identified proteins were grouped as hypothetical. However, 12% of them were well-known allergens, including AraH. The remainder were grouped as storage, enzymes, and binding proteins.
        4,000원
        90.
        2013.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nano-sized β-SiC nanoparticles were synthesized combined with a sol-gel process and a carbothermal process. TEOS and carbon black were used as starting materials for the silicon source and carbon source, respectively. SiO2 nanoparticles were synthesized using a sol-gel technique (Stober process) combined with hydrolysis and condensation. The size of the particles could be controlled by manipulating the relative rates of the hydrolysis and condensation reactions of tetraethyl orthosilicate (TEOS) within the micro-emulsion. The average particle size and morphology of synthesized silicon dioxide was about 100nm and spherical, respectively. The average particles size and morphology of the used carbon black powders was about 20nm and spherical, respectively. The molar ratio of silicon dioxide and carbon black was fixed to 1:3 in the preparation of each combination. SiO2 and carbon black powders were mixed in ethanol and ball-milled for 12 h. After mixing, the slurries were dried at 80˚C in an oven. The dried powder mixtures were placed in alumina crucibles and synthesized in a tube furnace at 1400~1500˚C for 4 h with a heating rate of 10˚C/min under flowing Ar gas (160 cc/min) and furnace cooling down to room temperature. SiC nanoparticles were characterized by XRD, TEM, and SAED. The XRD results showed that high purity beta silicon carbide with excellent crystallinity was synthesized. TEM revealed that the powders are spherical shape nanoparticles with diameters ranging from 15 to 30 nm with a narrow distribution.
        3,000원
        91.
        2013.03 구독 인증기관 무료, 개인회원 유료
        This study was conducted in order to examine the effects of alcohol-free cetylpyridinium chloride drinking water additive and oral gel on clinical parameters related to periodontal disease in beagle dogs. This study was conducted with healthy 15 beagle dogs. Following a professional teeth cleaning procedure, dogs were divided into three groups. Dogs in the control group received nothing, those in the drinking water additive (DWA) group received 800 ml water with 15 ml of alcohol-free cetylpyridinium chloride drinking water additive daily, and those in the Oral gel (OG) group were treated with oral gel containing alcohol-free cetylpyridinium chloride and 0.05% chlorhexidine gluconate daily. Clinical parameters, including plaque index (PI), calculus index (CI), and gingivitis index (GI) were evaluated at two and four weeks. Dogs in the DWA and OG groups had significantly less plaque than dogs in the control group at two and four weeks (P<0.01, P<0.05). And, at four weeks, CI was significantly lower in the OG group compared to the control group (P<0.05). On GI, similar scores were recorded for all groups during the experimental period. No significant difference was observed between the DWA group and the OG group. The effect of alcohol-free cetylpyridinium chloride drinking water additive was similar to the result for alcohol containing cetylpyridinium chloride mouthwash reported in a previous study. The effect in control of periodontal disease was better in the OG group because of additional chlorhexidine gluconate. However, use of drinking water additive will be more convenient for owners; thus, it will be more effective for achievement of long-term results.
        4,000원
        92.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two fractions (permeate and retentate) from fiber-free Aloe vera gel were separated using ultra-filtration (UF) system with tubular ceramic membrane (MWCO of 50 kDa), and their molecular properties were investigated. The retentate of UF Aloe gel was a polysaccharide-rich fraction containing about 2.3-fold higher polysaccharide content than fiber-free gel. The FT-IR and 1H NMR spectra of this fraction showed the characteristic patterns of β-binding polysaccharide and a higher degree of acetylation indicating a higher level of bioactive polysaccharide content. The molecular weight and polydispersity of polysaccharide fraction from GPC (gel permeation chromatography) were determined to be 36.8-43.9 kDa and 1.24, respectively, indicating a kind of undispersed polysaccharide. From the SEM observation, the surface structure of polysaccharide fraction had a gel cluster-like structure with a convoluted rough surface. The molecular conformation by Congo red assay exhibited a property of helix structure confirming the existence of a higher-ordered structure as a biological activity conformation.
        4,000원
        93.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The optimization of dewatering and impregnation soaking (DIS) process for a concentrated Aloe vera product was investigated using Taguchi method in combination with desirability function analysis. Polyethylene glycol (PEG) as osmotic agent was adopted, and soaking temperature (T), immersion time (t), PEG concentration (C), PEG molecular weight (MW), and thickness of Aloe vera leaf slice (x) were selected as affecting variables. L16 (45) orthogonal array was designed by Taguchi method with four parameters such as water loss, solid gain, glucomannan, and anthraquinone contents as objective functions. An overall quality index was transformed from individual objective functions, and was optimized finally. The optimal setting for maximum overall desirability was obtained at 55oC (T), 2 hr (t), 40% w/v (C), 0.5 cm (x), and 4,000 Da. (MW). The obtained overall desirability was 0.7842. The order of affecting factors was T>C>x>MW≈x>t and the experimental results under optimum condition were similar to the prediction of an overall desirability of 0.8384. Also, it was found that the optimized DIS condition could be reproduced for a minimally processed Aloe vera product with high quality.
        4,200원
        94.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        (Na, K) NbO3 thick film was successfully achieved using a sol-gel coating process with the addition of polyvinylpyrrolidone (PVP) to a metal alkoxide solution. The transparent coating solution, mixed with Nb:PVP = 1:1 in a molar ration, was synthesized by evaporating the solvent to over 62.5 wt%. Additive PVP increased the viscosity of the solution so that the coating thickness could be enhanced. The thickness of the (Na, K) NbO3 film assisted by PVP was ca. 320 nm at the time of deposition; this value is four times thicker than that of the sample fabricated without PVP. Also, due to PVP binding with the OH groups of the metal alkoxide, the condensation reaction in the film was suppressed. The crystalline size of the (Na, K) NbO3 films assisted by PVP was ca. 15 nm smaller than that of the film fabricated without PVP. After the sintering process at 700˚C, the (Na, K) NbO3 films were mainly composed of randomly oriented (Na, K) NbO3 phase of perovskite crystal structure, including a somewhat secondary phase of K2Nb4O11. However, by adding PVP, the content of the secondary phase became quite smaller than that of the sample without PVP. It was thought that the addition of PVP might have the effect of restraining the loss of potassium and that PVP could hold metalloxane by strong hydrogen bonding before complete decomposition. Therefore, the film thickness of the (Na, K) NbO3 films could be considerably advanced and made more crack-free by the addition of PVP.
        4,000원
        95.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper describes the spherical ammonium diuranate gel particles which are the intermediated material of the microsphere for an VHTR(very high temperature reactor) nuclear fuel. The characteristics of the intermediate-ADU gel particles prepared by AWD(ageing, washing, and drying) and FB(fluidized-bed) apparatus were examined and compared in a sol-gel fabrication process. The electrical conductivity of washing filtrate from the FB treating and the surface area of dried-ADU gel particles were higher than those of AWD treating. Also, an internal pore volume in dried-ADU gel particles showed a more decrease in AWD treatment than FB treatment because of decomposition of PVA affected by the washing time. However, the internal microstructures of ADU gel particles were similar regardless of the process variation.
        4,000원
        96.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study intented to standardize the method for total polysaccharide, which is a functional marker for aloe vera gel in Korea. We used four lyophilized raw materials and commercial aloe gel products, certified as Health Functional Food by Korea Food and Drug Administration, including powder, solution, jelly, tablet and capsule, to optimize the analytical condition of dialysis and phenol-sulfuric acid reaction in polysaccharide analysis. The optimal conditions for polysaccharide analysis included 1 L water for dialysis and change 3 times for 24hr against 25 mL prepared sample solution. Validation test showed lower than 5% of coefficient of variation(CV) in intra-, interday validation in lyophilized raw materials and 4 types of commercial products. In inter-person and inter-laboratory validation with 4 persons from 4 different laboratories, CV(%) were 5.50 and 6.64 respectively. The linearity of polysaccharide analysis was assessed using 5 serial concentration of lyophilized raw materials(0.1, 0.2, 0.3, 0.4, 0.5%(w/v)). The results showed R2 ≥ 0.995 of high linearity. In the commercial aloe vera gel products, the results of reproductivity showed lower than 7.08% and revealed that the standardized method from this study ensured high precision for polysaccharide analysis.
        4,000원
        97.
        2012.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Li1+xAlxTi2-x(PO4)3(LATP) is a promising solid electrolyte for all-solid-state Li ion batteries. In this study, LATP isprepared through a sol-gel method using relatively the inexpensive reagents TiCl4. The thermal behavior, structuralcharacteristics, fractured surface morphology, ion conductivity, and activation energy of the LATP sintered bodies areinvestigated by TG-DTA, X-ray diffraction, FE-SEM, and by an impedance method. A gelation powder was calcined at 500oC.A single crystalline phase of the LiTi2(PO4)3(LTP) system was obtained at a calcination temperature above 650oC. The obtainedpowder was pelletized and sintered at 900oC and 1000oC. The LTP sintered at 900~1000oC for 6 h had a relatively low apparentdensity of 75~80%. The LATP(x=0.3) pellet sintered at 900oC for 6 h was denser than those sintered under other conditionsand showed the highest ion conductivity of 4.50×10−5S/cm at room temperature. However, the ion conductivity of LATP(x=0.3) sintered at 1000oC decreased to 1.81×10−5S/cm, leading to Li volatilization and abnormal grain growth. For LATPsintered at 900oC for 6 h, x=0.3 shows the lowest activation energy of 0.42eV in the temperature range of room temperatureto 300oC.
        4,000원
        98.
        2012.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fe/SiO2 core-shell type composite nanoparticles have been synthesized using a reverse micelle process combined with metal alkoxide hydrolysis and condensation. Nano-sized SiO2 composite particles with a core-shell structure were prepared by arrested precipitation of Fe clusters in reverse micelles, followed by hydrolysis and condensation of organometallic precursors in micro-emulsion matrices. Microstructural and chemical analyses of Fe/SiO2 core-shell type composite nanoparticles were carried out by TEM and EDS. The size of the particles and the thickness of the coating could be controlled by manipulating the relative rates of the hydrolysis and condensation reaction of TEOS within the micro-emulsion. The water/surfactant molar ratio influenced the Fe particle distribution of the core-shell composite particles, and the distribution of Fe particles was broadened as R increased. The particle size of Fe increased linearly with increasing FeNO3 solution concentration. The average size of the cluster was found to depend on the micelle size, the nature of the solvent, and the concentration of the reagent. The average size of synthesized Fe/SiO2 core-shell type composite nanoparticles was in a range of 10-30 nm and Fe particles were 1.5-7 nm in size. The effects of synthesis parameters, such as the molar ratio of water to TEOS and the molar ratio of water to surfactant, are discussed.
        4,000원
        99.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        태양광 또는 풍력을 이용해 발생된 에너지를 효율적으로 저장과 사용을 위한 납 축전지의 성능을 향상 시키기 위해 전해액을 Semi-gel화 하여 납축전지에 적용하여 시험한 결과, 다음과 같은 결과를 얻었다. Semi-gel 전해액은 silica를 5wt.% 혼합한 전해액이 1시간 30분경과 시 gel화가 시작되었다. 이는 전해액이 격리판과 극판 활물질 내부까지 완전히 스며들기에 충분한 시간으로 가장 적정한 gel화 시간을 나타내었다. Semi-gel 전해액을 사용한 납축전지와 액상 전해액을 사용한 납축전지의 방전 성능을 비교한 결과, 저율방전 성능은 semi-gel전해액이, 고율방전 성능은 액상 전해액이 높은 성능을 나타내었다. 이는 gel 전해액의 경우 액상 전해액에 비해 반응속도가 느려 고율방전 성능이 낮은 것으로 나타내었다. 수명성능을 DOD 10%, DOD 100%로 시험한 결과, 5%-silica 전해액이 액상 전해액을 사용한 납축전지에 비해 우수한 수명 성능을 나타내었다. 이는 Semi-gel상 태의 전해액이 납축전지 내부 화학반응 시 발생하는 gas의 재결합 효율을 높여 전해액 감액량이 최소화로 한 결과로 수명성능에서 큰 차이를 나타내었다. 태양광, 풍력 등과 같은 에너지 저장 효율을 높이고, 수명성능을 향상시키기 위해 전해액에 5%-silica전해액을 사용하면 전해액의 감액량이 최소로 되어 DOD 100% 수명시험의 경우 4.8%, DOD 10% 수명시험의 경우 20%의 수명성능이 향상되었다.
        4,000원
        100.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The sol-gel technique has been studied to fabricate a homogeneous Fe-Mo/MgO catalyst. Ambient effects (air, Ar, and H2) on thermal decomposition of the citrate precursor have been systematically investigated to fabricate an Fe-Mo/MgO catalyst. Severe agglomeration of metal catalyst was observed under thermal decomposition of citrate precursor in air atmosphere. Ar/H2 atmosphere effectively restricted agglomeration of bimetallic catalyst and formation of highly-dispersed Fe-Mo/MgO catalyst with high specific surface-area due to the formation of Fe-Mo nanoclusters within MgO support. High-quality thin-multiwalled carbon nanotubes (t-MWCNTs) with uniform diameters were achieved on a large scale by catalytic decomposition of methane over Fe-Mo/MgO catalyst prepared under Ar-atmosphere. The produced t-MWCNTs had outer diameters in the range of 4-8 nm (average diameter ~6.6 nm) and wall numbers in the range of 4-7 graphenes. The as-synthesized t-MWCNTs showed product yields over 450% relative to the utilized Fe-Mo/MgO catalyst, and indicated a purity of about 85%.
        4,000원
        1 2 3 4 5