• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.21-21
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• 1998

Polyethylene glycol(PEG) 또는 polycaprolactone(PCP)을 예비 중합체로 사용하고 butanetriol trinitrate와 diethylene glycoldinitrate를 가소제로, cyclo-tetramethylene tetranitramine을 주산화제로 사용한 고체 추진제를 제조하여 이들의 기계적 성질을 증진시키기 위한 연구를 하였다. PEG의 일부를 PCP로 대체 시 추진제의 기계적 성질은 증가하며 PCP만 사용시 추진제의 최대 인장 강도는 PEG만 사용시 보다 약 17%, 최대 응력 하에서의 신율은 약 59% 그리고 탄성 계수는 약 9% 증가한다. 그러나 예비 중합체로 PCP만을 사용한 추진제는 4$0^{\circ}C$, 90% 상대 습도하에서 보관시 추진제의 경도 변화 실험에서 6주 후에 경도가 0이 되며, 위의 조건하에서 보관 기간에 따른 PCP 바인더의 부피 팽윤 실험에 의해 초기 부피 팽윤 비와 팽윤비의 변화 속도가 PEG를 혼용한 바인더보다 크므로 PCP 사용시 수분에 대한 안정성은 저하됨을 알 수 있었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2006.04a
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• pp.58-58
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• 2006

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3073-3074
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• 2010

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.269.1-269.1
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• 2000

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.384-389
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• 2011

We made suspension of fumed silica in polyethylene glycol (PEG), studied rheological behavior as functions of contents of silica, dispersion condition, PEG molecular weight, temperature and contents of humidity. Rheological behavior of suspension was determined critical shear rate and rise of viscosity using rheometer AR2000. Suspension were PEGs of molecular weight 200, 400, and 600. Fumed silica suspensions of which silica contents are 5, 7, 9, 13, and 18% were prepared by normal mixing, homogenization and bead milling process. We observed their rheological behaviors at 10, 20, 30, and $40^{\circ}C$. As the PEG molecular weight and contents of silica increase, the critical shear rate was lowered. As the temperature increased, the critical shear rate was increased. Humidity contents of dispersion don't influence on the critical shear rate, but dispersion processes greatly affect the critical shear rate. The critical shear rate of suspensions prepared by the mixing process was the lowest, and that of suspensions prepared by the bead milling process was the highest. The rise in the shear viscosity of suspensions prepared by the mixing process is higher than that of suspensions prepared by the bead milling process. This was dependent on the dispersion condition of silica particle by dispersion process.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.505-511
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• 1994

Seeds of Rigitaeda pine tree(Pinus rigida${\times}$P. taeda) was primed with polyethylene glycol(PEG-6000) under different PEG concentrations, treatment period, and temperatures to test uniformity of germination. Coated seeds and PEG treated seeds were sown to compare germination, emergence, establishment, and seedling growth. The results obtained are summarized as follows : 1. As the concentration of PEG increased, as total germination percentage of pine tree was increased. Total germination percentage of pine tree seeds primed with PEG at 15 or $20^{\circ}C$ was better than the seeds treated at $10^{\circ}C$ compared to untreated seeds. 2. Germination rate was improved as primed period long and level of PEG concentration high. 3. Maximum germination rate was high with long PEG treatment period, and markedly improved when the seeds were primed at $20^{\circ}C$ 4. Priming with PEG at $20^{\circ}C$ for 12 days reduced time taken for germination. 5. Osmoconditioned seeds accelerated germination under drought condition with injurious effect of coated seeds by some chemicals. 6. There were much differences in establishment and dry matter production between drill and oversowing method, and primed seeds showed better performances than the coated seeds. Coating effects to seeds were better under drought soil condition rather than moderate moisture condition.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.695-698
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• 2000

We studied the viability and function of islet with monomethoxy polyethylene glycol (mPEG) grafted onto its membrane. Islets were isolated from rat and were repeatedly reacted with activated mPEG (mw 5000) in order to increase grafting density. The density of grafted PEG on the islet membrane was confirmed by Fluorescein-PEG-NHS. An assessment of islet viability using AO / PI staining method showed that multiple PEGylation did not reduce islet viability. The function of PEG grafted islets was evaluated by measuring released insulin from islets. Insulin secreted from the PEGylated islets for 1 h did not show any significant difference compared to control (non-PEGylated) islets. In addition, PEGylated islets responded in the same pattern as control islets in the perifusion test.

• Membrane Journal
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• v.19 no.4
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• pp.268-276
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• 2009

In this study the basic data were settled down to establish theory of membrane module and apparatus for measuring suspended solid per particle size. The theory and technique were different with the conventional weight method and light scattering method. For this purpose silica, dextran, kaolin, and PEG (polyethylene glycol) suspended solutions were filtrated through glass fiber membranes GF/C and GF/A on membrane module for measuring TMP (Trans-membrane pressure) changes using digital pressure gages. And the related equation between modified solution concentration and TMP change slope was derived from the TMP change experiments, and then suspended solid concentration of samples could be expected by the equation.

• Current Research on Agriculture and Life Sciences
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• v.21
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• pp.1-9
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• 2003

Plants are often subjected to periods of soil and atmospheric water deficit during their life cycle. To find critical levels for identification of tolerant rice variety to salt- and drought-stresses, we investigated the water deficiency in the leaf of a Dongjinbyeo (DJ) cultivar, identified as intolerant variety, subjected to NaCl- and Polyethylene glycol 6000 (PEG)- treatments. The relative water content and water potential in leaf of DJ plant sharply declined along the high concentration and time after treatment in NaCl- and PEG-treated rice plants. To elucidate the method of simple screening of tolerant variety to salt- and drought-stresses, we examined the relationship between relative water content and water potential of leaves in NaCl- and PEG-treated rice plants. The relationship between relative water content and water potential in leaf of DJ plant showed the highest correlation in 80 mM NaCl-treatment, and showed high correlation only 8% PEG treatment. These results indicate that the critical level of salt stress for screening of tolerant rice was 80 mM NaCl at 48 h after NaCl treatment, and the critical concentration of drought stress for screening of tolerant rice was 8% PEG at 96 h after PEG treatment.

• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.67-73
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• 2014

The oil in mackerel muscle was extracted using an environment friendly solvent, supercritical carbon dioxide (SC-$CO_2$) at a semibatch flow extraction process and an n-hexane. The SC-$CO_2$ was maintained at a temperature of $45^{\circ}C$ under pressures ranging from 15 to 25 MPa. The flow rate of $CO_2$ (27 g/min) was constant during the entire 2 h extraction period. The fatty acid composition of the oil was analyzed using gas chromatography (GC). Significant concentrations of eicosapentaenoic acid (EPA) acid and docosahexaenoic acid (DHA) acid were present in the SC-$CO_2$ extracted oil. The oil extracted using SC-$CO_2$ exhibited increased stability compared with n-haxane extracted oil. Particles of mackerel oil together with the biodegradable polymer, polyethylene glycol (PEG) were formed using a gas saturated solution process (PGSS) with SC-$CO_2$ in a thermostatted stirred vessel. Different temperatures ($45-55^{\circ}C$), pressures (15-25 MPa) and a nozzle size $400{\mu}m$ were used for PGSS with a 1 h reaction time. The stability of mackerel oil in the particles did not changed significantly.