• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.555-566
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• 2023

In this study, a composite phase change material (CPCM) produced using the SOL-GEL technique was developed as a thermal energy storage medium for low-temperature applications. Tetradecane and activated carbon (AC) were used as the core and supporting materials, respectively. The tetradecane phase change material (PCM) was impregnated into the porous structure of AC using the vacuum impregnation method, and a thin layer of silica gel was coated on the prepared composite using the SOL-GEL process, where tetraethyl orthosilicate (TEOS) was used as the silica source. The thermal performance of the CPCM was analysed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC results showed that the pure tetradecane PCM had melting and freezing temperatures of 6.4℃ and 1.3℃ and corresponding enthalpies 226 J/g and 223.8 J/g, respectively. The CPCM exhibited enthalpy of 32.98 J/g and 27.7 J/g during the melting and freezing processes at 7.1℃ and 2.4℃, respectively. TGA test results revealed that the AC is thermally stable up to 500℃, which is much higher than the decomposition temperature of the pure tetradecane, which is around 120℃. Moreover, in the case of AC-PCM and CPCM thermal degradation started at 80℃ and 100℃, respectively. The chemical stability of the CPCM was studied using Fourier-transform infrared (FT-IR) spectroscopy, and the results confirmed that the developed composite is chemically stable. Finally, the surface morphology of the AC and CPCM was analysed using scanning electron microscopy (SEM), which confirmed the presence of a thin layer of silica gel on the AC surface after the SOL-GEL process.

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.65-70
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• 1988

Synthesis and biological activity test are described for the (Z)-9-tetradecen-1-yl acetate(1) and (Z)-11-tetradecen-1-yl acetate(1) and (Z)-11-tetradecen-1-yl acetate(2), the sex pheromone of the summer fruit tortrix moth, Adoxophyes orana. 8-Bromoctan-l-ol THP ether was prepared from 8-bromoctan-l-ol. The lithium anion of 1-hexyne was alkylated with 8-bromoctan-l-ol THP ether gave 9-tetradecyn-l-ol THP ether. Catalytic hydrogenation over Pd/BaSO4 followed by deprotection afforded (Z)-9-tetradecen-l-ol. Acetylation gave (Z)-9-tetradecen-1-yl acetate(1). l0-Bromodecan-l-ol THP ether was obtained from l0-bromodecan-l-ol. In liquid ammonia with THF and HMPA as cosolvents, sodium acetylide could be alkylated with 10-bromodecan-l-ol THP ether to give 11-dodecyn-l-ol THP ether. 11-Dodecyn-l-ol THP ether was then treated with n-BuLi in THF to give the lithium acetylide, which was alkylated with bromoethane to afford 11-tetradecyn-l-ol THP ether. Catalytic hydrogenation, deprotection, and acetylative gave (Z)-11-tetradecen-1-yl acetate(2). The synthetic pheromone thus obtained was attractive to the males of the summer fruit tortrix in the field.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.576-581
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• 1987

Synthesis and Biological activity test are described for the (E)-11-tetradecen-1-yl acetate and (Z)-11-tetradecen-1-yl acetate, the sex pheromone of the Asiatic leafroller moth (Archippus breviplicanus Walsingham). 10-Bromodecan-1-ol THP ether was prepared from 10-bromodecan-1-ol. In liquid ammonia with THF and HMPA as cosolvents, sodium acetylide could be alkylated with 10-bromodecan-1-al THP ether to give 11-dodecyn-1-ol THP ether. 11-Dodecyn-1-ol THP ether was then treated with n-Buli in THF to give the lithium acetylide, which was alkylated with bromoethane to afford 11-tetradecyn-1-ol THP ether. 11-Tetradecyn-1-ol THP ether was then reduced over $Pd/BaSO_4$ and with Na in liquid $NH_3$ to give (Z)-11-tetradecen-1-ol THP ether and (E)-11-tetradecen-1-ol THP ether, respectively. (Z)-and (E)-11-Tetradecen-1-ol THP ether thus obtained were deprotected by refluxing in the presence of PPTS and ethanol. (Z)-and (E)-11-tetradecen-1-ol were acetylated with acetic anhydride to afford the final products, (Z)-11-tetradecen-1-yl acetate (1) and (E)-11-tetradecen-1-yl acetate (2), respectively. The synthetic pheromone thus obtained was attractive to the males of the Asiatic leafroller moth in the field.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.753-756
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• 2009

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.787-792
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• 2022

In winter, the excessive use of deicing salt deteriorates concrete pavement durability. To reduce the amount of deicing salt used, phase-change materials (PCMs) potentially offer an alternative way to melt snow through their latent heat storage characteristics. In this research, thermal energy storage concrete was developed by using PCM-impregnated expanded clay as 50 % replacement to normal aggregate by volume. In addition, to improve the thermal efficiency of PCM lightweight aggregate (PCM-LWA)-incorporated concrete, multi-walled carbon nanotubes (MWCNTs) were incorporated in proportions of 0.10 %, 0.15 %, and 0.20 % by binder weight. Compressive strength testing and programmed thermal cycling were performed to evaluate the mechanical and thermal responses of the PCM-LWA concrete. Results showed a significant strength reduction of 54 % due to the PCM-LWA; however, the thermal performance of the PCM-LWA concrete was greatly improved with the addition of MWCNTs. Thermal test results showed that 0.10 % MWCNT-incorporated concrete had high thermal fatigue resistance as well as uniform heat flow, whereas specimens with 0.15 % and 0.20 % MWCNT content had a reduced thermal response due to supercooling when the ambient temperature was varied between -5℃ and 10℃.