• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.8
• /
• pp.711-718
• /
• 2011

The thermoelastic behavior of the porous carbon/phenolic composites is studied using the thermomechanical response model of chemically decomposing composites. The model includes thermal dependence of the porous composites, porosity in the pyrolysis process, pore pressure due to decomposing gases, and shrinkage. The poroelastic coefficients are calculated based on representative volume element model and finite element analysis. The internal stress distribution caused by pores and pore pressure, and the overall deformation are verified. The effects of the poroelastic coefficients on the thermoelastic behavior are examined through numerical experiments.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.4
• /
• pp.544-549
• /
• 2014

In this study, the permeation efficiency (PE) of sea tangle (Laminaria japonica) extract (STE) into egg using the temperature change method (TCM) and pressure was investigated. STE was prepared in a volume of water equal to 10 times the weight of the sea tangle at $100^{\circ}C$ over a 3 hr period. The PE of iodine as a representative component of the STE as well as the total polyphenol content at ambient pressure were determined as follows: 1) after soaking in the STE at 30, 40, and $50^{\circ}C$ for 3 hr, and 2) after soaking in the STE at $4^{\circ}C$ immediately after soaking in distilled water at $50^{\circ}C$ for 1, 2, and 3 hr (TCM), respectively. The PE of iodine as well as the total polyphenol content improved as the temperature of the STE increased (P<0.05). The permeation of iodine was more rapid, and the total polyphenol content increased with the TCM (121 ${\mu}g/100$ mg and 1.74 mg/mL for 3 hr, respectively) compared to without the TCM (72 ${\mu}g/100$ mg and 1.48 mg/mL for 3 hr, respectively), and the highest PE was observed with the TCM after soaking at $50^{\circ}C$ for 3 hr. At a pressure of 5.0 MPa, the PE was more rapid with the TCM (139 ${\mu}g/100$ mg and 1.74 mg/mL for 90 min, respectively) than without the TCM (105 ${\mu}g/100$ mg and 1.56 mg/mL for 90 min, respectively). Consequentially, these results suggest that the preparation of seasonings and functional eggs using various components and bioactive substances is possible by the TCM.

• Journal of Korean Society of Forest Science
• /
• v.110 no.3
• /
• pp.431-439
• /
• 2021

The present study evaluated the antioxidant activity, skin wrinkle reduction, and whitening activity of Pinus koraiensiscone scale extracts made with three different solvents (ethanol, supercritical fluid, and a mixture of both). Total polyphenol content was 11.03 mg/g GAE in the supercritical fluid extractand 33.79 mg/g GAE in the 70% ethanol extract. Electron donating ability of 1,000 ㎍/mL extract was 13.60% in the supercritical fluid extract, 91.37% in 70% ethanol extract, and 71.62% in mixed solvent extract. SOD-like activities in 100 ㎍/mL extract using supercritical fluid, 70% ethanol, and mixed solvents were 16.49%, 21.84%, and 10.7%, respectively. The ABTS⁺ radical scavenging activities of 1,000 ㎍/mL extract were 38.19%, 80.23%, and 78.72%for supercritical fluid extract, 70% ethanol extract, and mixed solvent extract, respectively. Tyrosinase inhibitory activities in 1,000 ㎍/mL extract were 24.54%, 36.55%, and 15.23% for supercritical fluid extract, 70% ethanol extract, and mixed solvent extract, respectively. Elastase inhibitory activities in 1,000 ㎍/mL extract were 15.62%, 22.56%, and 26.64% for supercritical fluid extract, 70% ethanol extract, and mixed solvent extract, respectively. Skin astringent activity (81.23% with 5000 ㎍/mL extract) was only detected in the 70% ethanol extract. Supercritical fluid and mixed solvent extracts showed no such activity. Our analysis of Pinus koraiensiscone scale extracts show that the highest aggregate activity was found in the 70% ethanol extract, followed by mixed solvent and supercritical fluid extracts. Therefore, our results oppose the hypothesis stating supercritical extract has the highest total polyphenol content and antioxidant activity.

• The Journal of Internal Korean Medicine
• /
• v.21 no.2
• /
• pp.219-225
• /
• 2000

산화적인 스트레스가 여러가지 신경 및 비신경계에서의 병리원인으로 알려져 있다. 퇴행성 뇌질환에 대한 예방과 치료에는 항산화 방어기술이 주요대상이며 스테로이드 분자중에서 estrogen만이 산화적인 원인에 의한 신경세포사를 방어하는데 특이적인 효과를 가지고 있다. 본 연구는 천축황(天竺黃)의 항산화적 뇌신경 보호기전을 연구하는 것으로 신경세포주, 뇌세포막, 이의 산화적 정량실험법을 사용하여 천축황(天竺黃)이 갖는 항산화 및 신경보호활성이 소수성 페놀(phenolic molecules)성 물질과 유사함을 밝히게 되었다. 즉, 페놀성 물질로서 2,4,6-trimethylphenol, N-acetylserotonin, 및 5-hydroxyindole와 유사한 뇌신경 보호활성을 나타내었으며 천축황(天竺黃)은 생쥐의 N2a cell과 사람 SK-N-MC neuroblastoma cell에서 산화적인 글루탐산 독성에 대하여 보호를 하였다. 천축황(天竺黃)의 산화적 글루탐산 독성에 대한 보호활성은 과산화수소에 대한 것과 유사하였다. 이러한 항산화 활성은 $20\;{\mu}g/ml$에서, LDL의 산화적 보호 활성은 $5\;{\mu}g/ml$농도에서 발휘되었다 (최대활성은 $16\;{\mu}g/ml$). 이러한 결과는 천축황(天竺黃)이 노인성 치매에 보호효과가 있음을 시사하였다.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.10 no.4
• /
• pp.47-53
• /
• 2006

In this paper, the thermal insulator structure of a real rocket which is fabricated in a way that laminated composite rings are connected in series is analyzed using 3-dimensional axisymmetric finite element models. Simulation of cowl zone using a real operating conditions provides that the stress distribution in the laminated composite ring is largely influenced by ply-angles, axial dimensions, and boundary conditions. Notably the plylift that is the precursor to the wedge-out occurs in the ring-to-ring bonding region. It is hypothesized that after the plylift the wedge is dropped out due to the shear stresses in the ply-angle direction and axial compressive stresses.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.10b
• /
• pp.134-137
• /
• 2003

탄소섬유나 활성탄소섬유(activated carbon fiber, ACF)는 일반적으로 출발물질에 따라 polyacrylonitrile(PAN)계, 아크릴(acryl)계, 피치(pitch)계, 페놀(phenol)계 등으로 분류할 수 있다. 보통 습식, 용융 혹은 용융분사(melt-blown) 방사 방법에 의해 섬유 형태로 형성한 다음 산화성 가스 분위기에서 불융화 과정을 거쳐 열에 대한 안정성을 부여하여 불활성 분위기에서 탄소화하여 탄소섬유를 제조하거나, 수증기나 이산화 탄소와 같은 산화성 분위기에서 활성화하여 활성탄소섬유를 제조한다. (중략)

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.4
• /
• pp.797-806
• /
• 2000

The objectives were to compare the biodegradable threshold concentrations of phenol with the different composition of the influent carbon source and examine the SMA (Specific Methanogenic Activity)and the possibility of simultaneous removal of high-strength organics and nitrogen compounds in UASB(Upflow Anaerobic Sludge Blanket) - PBR(Packed Bed Reactor) process. The results showed that UASB reactors were efficient to remove phenol and phenol + glucose from synthetic wastewater. At phenol conc, of 600 mg/L and SCOD conc. of 2100 mg/L in UASB reactor(with only phenol as substrate), the removal efficiencies of phenol and SCOD were over 99% and 93% respectively, under MLVSS of 20 g. The activity of microorganism was $0.112g\;phenol/g\;VSS{\cdot}d$, $0.351g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.115L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. At phenol conc. of 760 mg/L and SCOD conc. of 4300 mg/L in UASB reactor( with phenol + glucose as substrates), the removal efficiencies of phenol and of SCOD were over 99% and 90% respectively, under MLVSS of 20 g. The activity of microoganism was $0.135g\;phenol/g\;VSS{\cdot}d$, $0.696g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.257L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. Serum bottle test showed that the activity of granule was inhibited over 1600 mg/L phenol conc, and denitrification and methanogenesis simultaneously took place in UASB granules under co-substrates conditions. PBR reactor packed with cilium type media, was efficient in nitrification. In condition of $0.038kg\;NH_4-N/m^3-media{\cdot}d$. 10~12 mg/L phenol conc. and 200~500 mg/L SCOD conc., nitrification efficiency was over 90% and phenol removal efficiency was over 98%.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1677-1679
• /
• 1999

Crosslinked LB films of p-HP (p-hexadecoxyphenol) were produced to insulation layers of electronic devices. The fabrication and the electrical properties of LB films according to crosslinking have investigated respectively to Brewster angle microscopy (BAM), Scanning Maxwell-stress microscopy (SMM), current-voltage (I-V) properties and frequency-capacitance (C-F) characteristics. According to crosslinking, conductivity of p-HP LB films have improved and relative dielectric constant have reduced.

• KSBB Journal
• /
• v.15 no.1
• /
• pp.22-26
• /
• 2000

Kraft Lignin which is produced abundantly in pulp industry, was chemically degraded into small oligomers and polymerized using horseradish peroxidase. Lignin acidolysis was optimized by controlling reaction time and HCI concentration. Acidolyzed lignin was polymerized and copolymers of acidolyzed lignin and phenol or p-cresol were synthesized. 70% of kraft lignin was degraded after acidolysis. Number average molecular weight of all lignin polymers were from 8,500 to 14,000 and did not show large difference. Differential scanning calorimeter analysis showed that acidolyzed lignin did not show any melting temparature under $300^{\circ}C$, which indicates that newly synthesized lignin polymers can be used in industry under mild condition.

• Textile Coloration and Finishing
• /
• v.20 no.4
• /
• pp.21-30
• /
• 2008

To understand the complex hydrogen bonding structure, several phenolic derivatives and benzoxazine model compounds are synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR). The estimation of molar extinction coefficients for various types of hydrogen bonding species is systematically carried out by the curve-resolving of FT-IR spectra. The distribution of hydrogen bonding species in benzoxazine model dimers is quantitatively analyzed. It is revealed that benzoxazine dimers and BA-a polybenzoxazine are mainly composed of intramolecular interaction rather than intermolecular interaction.