• Polymer(Korea)
• /
• v.34 no.3
• /
• pp.261-268
• /
• 2010

Phase change materials based on polypropylene blended with n-eicosane were studied in this paper. In addition, this paper reviews recent studies on the preparation of shape stabilized phase change materials (SSPCM), such as SSPCM from polypropylenes and n-eicosane, their basic properties and possible applications to latent heat storage. The preparation methods used were the melting method and absorption methods. Shape stabilized PCM(SSPCM) prepared for DSC, WAXD, FTIR spectroscopy, ARES, results of the analysis of shape stability heat capacity to improve were identified.

• Fibers and Polymers
• /
• v.7 no.1
• /
• pp.12-19
• /
• 2006

For thermal adaptable fabrics, the polyurethane-urea microcapsules containing phase-change materials (PCMs: hexadecane, octadecane and eicosane) were successfully synthesized by interfacial polycondensation using 2,4-toluene diisocyanate (TDI)/poly(ethylene glycol) (PEG400)/ethylene diamine (EDA) as shell monomers and nonionic surfactant NP-12 in an emulsion system under stirring rates of $3,000{\sim}13,000$ rpm. The mean particle size of microcapsule decreased significantly with increasing the stirring rate up to 11,000 rpm, and then leveled off. The mean particle size increased with increasing the content and molecular weight (eicosane > octadecane > hexadecane) of PCMs at the same stirring rate. The mean particle sizes of microcapsules were found to decrease with increasing the NP-12 content up to 1.5 wt%, and thereafter increased a little. It was found that the melting temperature ($T_m$) and crystallization temperature ($T_c$) of three kinds of encapsulated PCMs and their enthalpy changes (${\Delta}H_m,{\Delta}H_c$) increased with increasing PCM contents. The encapsulation efficiencies (Ee) of hexadecane microcapsule linearly increased with increasing the content of hexadecane. It was found that the stable microcapsule containing 50 wt% of hexadecane could be obtained in this study. However, Ee of octadecane and eicosane microcapsules increased with increasing PCM's contents up to 40 wt%, and then decreased a little. By considering the encapsulation efficiency, it was found that the maximum/optimum contents of octadecane and eicosane microcapsules were about 40 wt%. By the dynamic thermal performance test, it was found that the maximum buffering levels of Nylon fabrics coated with hexadecane, octadecane, and eicosane microcapsules were about $-2.4/+2.9^{\circ}C,\;-3.6/+3.6^{\circ}C\;and\;-4.0/+4.7^{\circ}C$, respectively.

• The Korean Journal of Food And Nutrition
• /
• v.33 no.3
• /
• pp.257-265
• /
• 2020

This study investigated the volatile flavor composition of essential oils from Solidago virga-aurea var. asiatica Nakai with different harvesting area. The essential oils obtained by the hydrodistillation extraction method from the aerial parts of the plants were analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Ninety-five (91.61%) volatile flavor compounds were identified in the essential oils from the S. virga-aurea var. asiatica Nakai harvested in Koheung, Jeolanamdo. The major compounds were hexadecanoic acid (29.22%), 7-hexyl eicosane (9.12%), spathulenol (7.701%), 3,8-dimethyl decane (6.48%), caryophyllene oxide (4.52%) and α-copaene (4.23%). Fifty-seven (97.43%) volatile flavor compounds were identified in the essential oils from the S. virga-aurea var. asiatica Nakai harvested in Seoguipo, Jejudo. The major compounds were 2-carene (40.95%), α-copaene (10.77%), α-muurolene (5.81%), and spathulenol (3.11%). The chemical composition of the essential oils was significantly different in quality and quantity with the different harvesting area. The quantitative variations of hexadecanoic acid, 7-hexyl eicosane, spathulenol, 3,8-dimethyl decane, caryophyllene oxide, 2-carene, and α-copaene according to different harvesting area can serve as a quality index of the S. virga-aurea var. asiatica Nakai essential oils in food industries.

• Korean Journal of Acupuncture
• /
• v.26 no.4
• /
• pp.211-223
• /
• 2009

초임계추출법과 수증기증류법을 이용하여 황련해독탕의 정유성분을 추출하여 성분 패턴을 비교하였다. 이때 초임 계추출조건은 압력 200 atm, $45^{\circ}C$ 그리고 추출시간 25분 이었다. 이때의 추출된 성분의 93.9%인 37개의 성분을 가스크로마토그래피/질량분석기로 확인하였다. 주요성분으로는 tetradecenoic acid (11.7%), Vanillin (5.9%), dl-Limonene (5.5%) 및 Eicosane (4.6%)으로 나타났다. 수증기증류법으로 추출한 정유에서는 34개 성분을 확인할수 있었다. 주요성분으로는 tetradecenoic acid (8.9%), Vanillin (5.8%)및 Eicosane (4.7%)를 확인 할 수 있었다. 또한 구강내의 12균주를 이용하여 항균효과를 측정하여 최소엑제농도(MIC)와 사멸농도(MBC) 0.025 - 12.8 mg/ml와 0.05 - 12.8 mg/ml 각각 나타났다.

• Bulletin of the Korean Chemical Society
• /
• v.17 no.10
• /
• pp.949-951
• /
• 1996

• Bulletin of the Korean Chemical Society
• /
• v.21 no.3
• /
• pp.358-360
• /
• 2000

• 한국기계연구소 소보
• /
• s.19
• /
• pp.23-30
• /
• 1989

Heat transfer phenomena of solidification process of the phase change material within cylindrical can is studied experimentally. N-Eicosane paraffin wax is used for phase change material and its melting temperature is 309.8 K. In order to achieve higher heat transfer rate of latent heat storage apparatus, fins in made of copper are used in the cylindrical can. If there are fins in cylindrical can, we can know that the inward latent heat energy in paraffin can be effectively transfered to cooling water than if finless.

• Korean Journal of Microbiology
• /
• v.48 no.1
• /
• pp.37-41
• /
• 2012

In this study, we screened and evaluated possibility of wood rot fungi as biocatalyst for biotransformation of sesquiterpenes. Screening were performed to select the most promising microorganisms with ability to biotransformation the substrate trans,trans-fanesol. Trans,trans-farnesol which is synthesized precursor of sesquiterpenes was used for resistance test on 19 of wood rot fungi. From the 19 tested wood rot fungi, 5 were selected by resistance test on different concentration of trans,trans-fanesol. Biotransformation was performed with selected wood rot fungi on liquid culture. The metabolites detected by GC-MS analysis were nerolidol for Laetiporus sulphureus var. miniatus (jungh) Imaz and eicosane for Coriolus versicolor (L.Fr) Prlar and isoborneol for Fomitopsis pinicola and isocyclocitral for Lampteromyces japonicas. As the results, wood rot fungi could be potential biocatalyst for biotransformation of sesquiterpenes.

• Applied Biological Chemistry
• /
• v.46 no.3
• /
• pp.214-219
• /
• 2003

The fractions extracted with methylene chloride from colored rice seeds of 19 cultivars were prepared to examine the correlationties of both antimutagenicity and antioxidiativity with physiological functionalities. The data revealed a positive correlation of the antimutagenicity with the content of $(3.{\beta},22Z)-Acetate-stigmasta-5,22-dien-3-ol$, 24-Oxocholesterol acetate, 6(E),8(E)-Heptadiene, and Eicosane. For antioxidativity, electron donating ability to DPPH radicals exhibited a positive correlation with the content of (24R,25S)-Aplysterylacetate, however, negative correlations were found between scavenging activity toward hydroxyl radicals and the content of either Tetradecanoic acid or Methyl ester-hexadecanoic acid, $(3.{\beta},24S)-Stigmast-5-en-3-ol$, respectively. In addition, a positive correlation was detected between the inhibitory effect of the fractions and the content of $(3.{\beta},24S)-Stigmast-5-en-3-ol$, however, a negative correlation with the content of 3',3'-Dimethylspiro [acridane-9,1'-indane], $(3.{\beta})-24-Methylene-9,19-cyclolanostan-3-ol$, and some other compounds was observed, respectively.

• Bulletin of the Korean Chemical Society
• /
• v.11 no.3
• /
• pp.206-208
• /
• 1990

Cu(II) hexaazamacrotricyclic complexes $[Cu(L)](ClO_4)_2$ and $[(Cu(L)Cl]ClO_4$, where L = 1,3,6,9,11,14-hexaazatricyclo$[12.2.1.1^{6,9}]octadecane(L_1)$ or 1,3,6,10,12,15-hexaazatricyclo$[13.3.1.1^{6,10}]eicosane(L_2)$, have been prepared by the simple template condensation reactions of triamines, diethylenetriamine for $L_1$, and N-(2-aminoethyl)-1,3-propanediamine for $L_2$, with formaldehyde in the presence of $Cu(OAc)_2\;or\;CuCl_2$. The Cu(II) complexes of $L_1$ contain two 1,3-diazacyclopentane ring moieties and those of $L_2$ contain two 1,3-diazacyclohexane ring moieties that are fused to the 14-membered macrocyclic framework. Spectra indicate that complexes $[Cu(L)](ClO_4)_2\;and\;[Cu(L)Cl]ClO_4$ have square-planar and square-pyramidal chromophores, respectively. square-planar $[Cu(L)](ClO_4)_2$ are remarkably stable against ligand dissociation in acidic aqueous solutions. Square-pyramidal $[Cu(L)Cl]ClO_4$ complexes dissociate their axial Cl-ligands easily in aqueous solutions to form $[Cu(L)H_2O]^{2+}$ species. Infrared and UV/vis absorption spectra of the Cu(II) complexes reveal that Cu-N interactions and the ligand field strengths are significantly weaker in the complexes of $L_2$ than in the complexes of $L_1$.