• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.3
• /
• pp.262-271
• /
• 2000

This study was carried out to clarify the spatial and temporal patterns of benthic environments and macrobenthos on the subtidal soft-bottom in Chonsu Bay. Seasonal surface water temperature was similar to the bottom layer, but freshwater discharges into the outlets dereased the surface salinity around the dyke in summer. Bottom dissolved oxygen was decreased deeply around the dyke and created the de-oxygenated layer during summer. Sediment grain size was consisted of finer at the neighboring of the dyke than the mouth of the bay. Organic matters including the sediment were decreased at the mouth of the bay. A total of 311 species ($769\;ind./m^2$) were identified. Polychaetes were the most abundant faunal group in the number of species and densities. The number of species revealed the spatial patterns that it was higher in the mouth of the bay, and their densities showed seasonal changes by mass recruitment occurred at the most of the area in summer, At this time, opportunistic species, Lumbrineris iongifolia and Theora fragilis, were also recruited massively. Chonsu Bay were classified into five station groups by the cluster analysis. The dominant species around the dyke were composed to opportunistic species, those in middle area were Sternaspis scutata, Paraplionospio pinnata, and those in the mouth of the bay were Mediomastus californiensis, Nephtys polybranchia. Seasonal fluctuations and spatial difference of environments seem to have influenced to the species compositions and affected to the stability of benthic ecosystems spatial-temporally In Chonsu nay.

• Polymer(Korea)
• /
• v.24 no.6
• /
• pp.737-743
• /
• 2000

Polyquinonediimines (PQDI) which have stable structure on heat and contains mono-azobenzene in the side chain were synthesized by means of condensation polymerization under TiCl$_4$. The synthesized monomers and polymers were identified by FT-IR, $^1$H-NMR, and elementary analysis. Especially, PQDI was comfirmed by the double-bonding peak of >C=N appeared near 1625 $cm^{-1}$ / by means of FT-IR spectrum. PQDI containing mono-azobenzene group in both side chains wat not soluble in non-polar solvents at all but partially soluble in the polar solvents having small dielectric constant, and dissolved in the strong acid such as sulfuric acid and $CH_3$SO$_3$H. Molecular weight distribution of PQDI measured by GPC showed 1.74. It was confirmed through X-ray diffraction analysis that the polymer was partially crystalline at the low angle region, but amorphous after heat treatment at 1$25^{\circ}C$. The glass transition temperature (T$_{g}$ ) of synthesized polymer was measured as 1$25^{\circ}C$ by differential scanning calorimetry. The SHG value for $\chi$$^{(2)}$ after poling at 1$25^{\circ}C$ was 8.6 pm/V (λ=1.542 ${\mu}{\textrm}{m}$). The SHG value slowly decreased with time from the start but appeared temporal stability after 100 hours.

• Korean Chemical Engineering Research
• /
• v.47 no.1
• /
• pp.38-45
• /
• 2009

In this study, interfacial properties were measured for imidazoline type cationic surfactant system which has been widely used as a fabric softener, a dispersant, an anti-static agent, a bleach activator, and an emulsifier. The CMC of imidazoline surfactant was near $6{\times}10^{-5}mol/L$ and the surface tension at CMC was about 32 mN/m. It was found that surface tension was not affected by surfactant concentration but decreased with an increase in pH. The interfacial tension between 1 wt% aqueous solution and n-dodecane was shown to be about 0.01 mN/m and equilibration time was not affected by pH. Phase behavior experiment in a binary aqueous surfactant system showed that only micellar solution of $L_1$ phase was found under conditions of temperature and pH investigated during this study. Only a two-phase region consisting of lower-phase microemulsion in equilibrium with excess oil phase existed under the same conditions, when oil was added to the binary surfactant system. The foam stability measured with 1 wt% surfactant solution increased with pH, which is consistent with surface tension measurement result. QCM(quartz crystal microbalance) measurement showed that surfactant adsorption increased with surfactant concentration but decreased with pH. According to the friction measurement, best fabric softening effect by imidazoline surfactant system was found under alkali conditions.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.3
• /
• pp.430-435
• /
• 2012

This study was carried out to investigate the rheological effects of black garlic extracts on the bread dough. 0, 5, 10 and 15% of black garlic extracts were added in the bread flour. Falling number, RVA (Rapid visco analyser), farinograph and alveograph were analyzed. Falling number was lowered by increasing the amount of the extract added in the wheat flour. The pasting characteristics of the dough by RVA, value of pasting temperature, peak viscosity, holding strength, final viscosity, break down and set back were increased compared to the control. In the Farinograph analysis, the consistency and the water absorption ratio were elevated with the increase of the extract added. However, the rapid decrease of stability and the time to breakdown values were observed by increasing the extract addition amount compared to the control. However the mixing tolerance index (MTI) was rapidly increased as the amount of the extract addition was increased, and the highest farinogram quality number was observed in the control. Through the alveograph analysis, $P_{max}$ value was found to show the highest value in the control, while the L and G values were higher but W values was lowered in the dough with added 15% black garlic extract. As a result of the analysis, there was no significant bad effect until 5% of black garlic extracts was added to the bread dough.

• Journal of Conservation Science
• /
• v.29 no.2
• /
• pp.127-138
• /
• 2013

Plastic, widely used as a material for contemporary art, get damaged as directly exposed to temperature, humidity, ultra violet, etc. And it is very quickly damaged in early time, once damaged, it can't recover into original state. But like this characteristics, there is a few advanced research in Korea. So this study deal with a rising value of plastic artifacts in other country, United Kingdom and France, current conservation state, identification and cleaning method. Also 5 types of cleaners(distilled water, ethanol, acetone, eraser) and adhesives(cyanoacrylate, epoxy, acrylic, chloroprene rubber) were evaluated by produced plastics(PVC, PE, PP, PS, PU). As a result of experiment, ethanol and acetone that were previous evaluated in other research performed in other country are the best cleaner. Result of degradation after adhesive, cyanoacrylate and epoxy resin showed better performance and stability. As a basic research, this study is expected that can be used in future researches.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.4 no.4
• /
• pp.393-400
• /
• 2006

In design of a deep geological repository for the high level wastes, it is very important that the temperature of the bentonite block should not be over $100^{\circ}C$ to maintain the integrity of the bentonite buffer block from the decay heat. In this study, for the layout of the repository to meet the requirement, the analysis of the disposal tunnel and disposal pit spacing was carried out. To do this, based on the reference repository concept, several cases of cooling times and disposal tunnel and disposal pit spacing were compared. The thermal stabilities of the disposal systems were analyzed in terms of the cooling time and spacing. The results showed that it was more desirable to determine the layout of the repository in terms of disposal pit spacing than the disposal tunnel spacing. The results of these analyses can be used in the deep geological repository design. The detailed analyses with the exact site characteristics data will reduce the uncertainty of the results.

• Applied Chemistry for Engineering
• /
• v.19 no.5
• /
• pp.526-532
• /
• 2008

The proposed $CO_2$ storage technology in the present study is a one-step sequestration process that stabilizes $CO_2$ in a reactor with Serpentine. The advantage of this technology is associated with its high stability of final product so that the entire system is recognized as permanent environment-friendly $CO_2$ removal method. Since the sequestration reaction mechanisms are generally understood that carbonation reaction proceeds with very slow rate, so that pretreatment method to increases reaction rate of $CO_2$ carbonation reaction should be developed. To increase the reactivity of Serpentine with $CO_2$, two different methods of pretreatment are carried out in the present investigation. One is heat-treatment, the other is chemical pretreatment. In this study, only chemical pretreatment is considered leaching method of magnesium from Serpentine using sulfuric acid at the various reaction temperatures, times, and acid concentrations. Experimental results illustrated that pretreatment by sulfuric acid increases surface area of serpentine from $11.1209m^2/g$ to $98.7903m^2/g$ and extracts magnesium compounds. Single variable experiment demonstrated the enhancements of magnesium extraction with increased reaction temperature and time. Amount of magnesium extraction is obtained by using the data of ICP-AES as maximum extraction condition of magnesium is 2 M acid solution, $75^{\circ}C$ and 1hr. After performing chemical pretreatment, carbonation yield increased from 23.24% to 46.30% of weight.

• Korean Journal of Food Science and Technology
• /
• v.39 no.6
• /
• pp.652-657
• /
• 2007

This study was performed to evaluate the physicochemical and quality characteristics of bread with Enteromorpha intenstinalis added. In order to compare the physical and organoleptic properties, 1 to 4% of E. intenstinalis powder was mixed with the flour. Among the physical characteristics of the dough, the absorption ratio in the farinogram and the degree of attenuation increased with increasing amounts of E. intenstinalis powder, whereas the development time, dough stability, the degree of extension, the degree of resistance, and R/E became reduced. In the amylogram, there was no difference in the gelatinization starting temperature among the samples, but the maximum viscosity gradually increased according to increasing amounts of E. intenstinalis powder. Also, a sensory evaluation was carried out in terms of acceptability (color, flavor, moistness, tenderness, mouth feel, and overall acceptability). Taken together, the 2% treatment showed the highest evaluation values, as compared to the other treatments.

• Applied Chemistry for Engineering
• /
• v.17 no.1
• /
• pp.52-57
• /
• 2006

Coptidis Rhizoma, an antimicrobial agent from natural source, is known to have the antiviral effect on the Candida albicans that causes the infectious dermatitis. The valuable protein was extracted from the Coptidis Rhizoma, To prevent denaturalization from external stimulus and improve adsorption onto the skin, the nano-sized liposomes were prepared as a carrier. The CPR-containing liposomes showed an average diameter of 187 nm, surface charge of 3.337 mV and 33% encapsulation efficiency. The release behavior of CRP from the liposome was investigated with various temperature and releasing time. The PVA solution was coated on the surface of liposome to improve the stability. The coated liposome showed slow release behavior in comparison with the non-coated liposome. The CRP in the liposome maintained the effect on the Candida albicans after treating it at 50 and with ultraviolet for 24 h.

• Korean Journal of Food Science and Technology
• /
• v.35 no.3
• /
• pp.347-352
• /
• 2003

In order to compare quality characteristics and oxidative stabilities of rice germs prepared under different roasting conditions, sensory evaluation, color value, tocols (tocopherol+tocotrienol) contents, and peroxide value were investigated. Optimum roasting temperatures for the best acceptability were 20, 10, and 6 min at 170, 180 and 190, respectively. Hunter color a values of rice germ increased as roasting temperature and time increased, whereas L value decreased. Peroxide values of unroasted, and roasted rice germs at $170^{\circ}C$ for 20 min, $180^{\circ}C$ for 10 min, and $190^{\circ}C$ for 6 min were 2.0, and 145.6, 169.5, and 182.9 meq/kg, respectively, after 9 days storage at $60^{\circ}C$. Four tocopherol and three tocotrienol isomers were identified, whereas no ${\beta}$-tocotrienol was detected. The major tocopherol and tocotrienol isomers in rice germ were ${\alpha}$-tocopherol and ${\alpha}$-tocotrienol, respectively. ${\alpha}$-Tocopherol content in roasted rice germ decreased significantly during storage, whereas those of ${\beta}$- and ${\gamma}$-tocopherols slowly decreased. ${\delta}$-Tocopherol had the highest stability among tocopherol isomers in roasted rice germ. Similar trends were observed in tocotrienol isomers.