• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.4
• /
• pp.373-379
• /
• 1994

Final biomass yields(cells/ml) and growth rates(divisions/day) of 4 clones of marine diatoms isolated from the Korean coastal waters were measured in media with 6 different levels of added cadmium concentrations. A neritic diatom, GS-12(Chaetoceros sp.), showed no growth at 0.1ppm cadmium, and its $IC_{50}$ for final biomass yield and growth rate was 0.03 and 0.02ppm, respectively. Two clones isolated from tidal pool, NC-37 and NC-29, showed enhanced tolerance to cadmium toxicity. Extremely high tolerance to cadmium addition was found in J-21 from a eutrophicated bay, with its high $IC_{50}$ for biomass yield(1.07ppm) and growth rate(1.92ppm). Present results implied a habitat related pattern of coastal diatom clones in the cadmium tolerances. Except GS-12, the other three diatom clones are considered to be highly tolerant to cadmium stresses.

• The Korean Journal of Mycology
• /
• v.22 no.2
• /
• pp.130-137
• /
• 1994

This experiment was carried out to investigate proper conditions for protoplast isolation and regeneration from mycelia of Lyophyllum decastes. Novozym 234(10 mg/ml) with 0.6 M $MgSO_4$ in phosphate buffer(pH 4.0) was proper for protoplast isolation. The optimal reaction time of the mycelium with the lytic enzyme was four hours in shaking condition at 120 strokes per min. When the mycelium of L. decastes was cultured at $24^{\circ}C$ for 5 days, the formation of protoplasts was effective. The liquid medium was more effective for protoplast isolation than the solid medium. In the liquid medium, high yields of protoplasts were obtained from 0.6 M $MgSO_4$ osmotic stabilizer. Protoplasts of L. decastes were regenerated to normal hyphal growth and the regeneration frequency of the protoplasts in the complete agar medium containing Triton X-100(0.0025%) was $5.94{\sim}8.32%$. The regeneration medium stabilized with 0.6 M sucrose was the best for regeneration of the protoplasts. In contrast to protoplast formation, regeneration was inhibited by the inorganic salts used as osmotic stabilizer.

• Nuclear Engineering and Technology
• /
• v.52 no.8
• /
• pp.1756-1763
• /
• 2020

The paper studies spark plasma sintering (SPS) of industrially used UO₂-based fuel containing integral fuel burnable absorber (IFBA) of neutrons Gd₂O₃. Densification dynamics of pristine UO₂ powder and the one added with 2 and 8 wt% of Gd₂O₃ under ultrasonication in liquid has been studied under SPS conditions at 1050, 1250, and 1450 ℃. Effect of sintering temperature on phase composition as well as on O/U stoichiometry has been investigated for UO₂ SPS ceramics. Sintering of uranium dioxide added with Gd₂O₃ yields solid solution (U,Gd)O₂, which is isostructural to UO₂. SEM with EDX and metallography were implemented to analyze the microstructure of the obtained UO₂ ceramics and composite UO₂-Gd₂O₃ one, particularly, open porosity, defects, and Gd₂O₃ distribution were studied. Microhardness, compressive strength and density were shown to reduce after addition of Gd₂O₃. Obtained results prove the hypothesis on formation of stable pores in the system of UO₂-Gd₂O₃ due to Kirkendall effect that reduces sintering efficiency. The paper expands fundamental knowledge on pros and cons of fuel fabrication with IFBA using SPS technology.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.16 no.3
• /
• pp.222-232
• /
• 2006

Objectives: The objective of this study was to propose the total isocyanate analytical method which involves derivation of 2,4-toluene diisocyanate(2,4-TDI), 2,6-toluene diisocyanate(2,6-TDI), 4,4'-methylenediphenyl diisocyanate(4,4'-MDI) and 1,6-hexamethylene diisocyanate(1,6-HDI) using 2-chlorobenzyl alcohol(2-CBA) or 2,4-dichlorobenzyl alcohol(2,4-DCBA), and analyzing of hydrolysate of the synthesized urethane with the gas chromatography(GC)/flame ionization detector(FID), GC/pulsed discharge ionization detector-electron capture detector(PD-ECD) and GC/mass selective detector(MSD). Methods: Urethanes were synthesized by reacting 2,4-TDI, 2,6-TDI, 4,4'-MDI and 1,6-HDI to 2-CBA or 2,4-DCBA. Urethanes was verified by TLC, HPLC/UVD and GC/MSD. For field application, the most suitable condition that 2-CBA coated in glass fiber filter removed completely and urethanes were not removed was searched. 2-CBA generated from hydrolysis of urethanes according to hydrolysis conditions. Diisocyanates were collected on field air and analyzed. Results: Urethanes which were white and solid phase synthesized by reacting 2,4-TDI, 2,6-TDI, 4,4'-MDI, 1,6-HDI and 2-CBA or 2,4-DCBA. And urethanes were verified by TLC, HPLC/UVD and GC/MSD. The most suitable conditions to remove 2-CBA coated in glass fiber filter were $87^{\circ}C$ and 20 mmHg and urethanes were not removed under same condition. Hydrolysis yields of urethanes were 99 % to 111 %. 2-CBA, the hydrolysate of urethanes was analyzed by GC/FID, GC/PD-ECD and GC/MSD. Conclusions: Simultaneous analysis of 2,4-TDI, 2,6-TDI, 4,4'-MDI and 1,6-HDI deriving with 2-CBA and 2,4-DCBA, along with a total isocyanate analysis, was feasible with GC/FID, GC/PD-ECD and GC/MSD. This result will be a guide of further study on total isocyanate analysis.

• Journal of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.689-698
• /
• 1991

Activated oxidation catalysts are generated by the treatment of pentadentate Schiff base cobalt(Ⅱ) complexes with the oxygen saturated DMF solution. Oxidation of 2,6-di-tert-butylphenol by homogeneous oxidation catalysts of superoxo type pentadentate schiff base cobalt(Ⅲ) complexes yields 2,6-di-tert-butylbenzoquinone(BQ) as a major product. And $O_2$/Co mole ratio of homogeneous oxidative catalysts such as [Co(Ⅲ)(sal-DET)]$O_2$ and [Co(Ⅲ)(sal-DPT)]$O_2$by PVT method of the oxygen absorption in DMSO and pyridine solution was 1:1, 1:1.52 in DMF solution and ${\mu}$-peroxo type cobalt(Ⅲ) complexes formed at solid state. The redox reaction processes of superoxo type cobalt(Ⅲ) complexes as homogeneous oxidation catalysts were investigated by cyclic voltammetry and DPP method at a glassy carbon electrode. As a result of electrochemical measurements the reduction processes of oxygen adducted superoxo type cobalt(Ⅲ) complexes occurred to four steps including prewave of $O_2$-in 0.1M TEAP-DMSO and 0.1 M TEAP-Pyridine as supporting electrolyte solution.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.8
• /
• pp.1149-1155
• /
• 2010

This study was conducted to investigate the changes of quality characteristics, and mineral, oxalate and phytate content during soymilk process. The yields of soymilk ranged from 8.43 mL/g in Bokwangkong to 9.15 mL/g in Bongeuikong and Hannamkong, and total soluble solid contents were ranged from $4.37^{\circ}Brix$ in Anpyeongkong to $7.17^{\circ}Brix$ in Bongeuikong, respectively. The pH and total acidity of soymilk ranged from 6.43 to 6.86 and from 1.48% to 1.65%, respectively. The viscosity of soymilk was the highest value of 20.80 cP in Hannamkong and the lowest value of 15.73 cP in Dawonkong. The highest value of calcium content of soymilk was 1.589 mg/g in Seonheukkong, and oxalate and phytate in soymilk were high at 2.14 mg/g in Hannamkong and 2.18 mg/g in Anpyeongkong, respectively. The transfer ratio of oxalate from soybean to soymilk was the highest value of 77.6% in Jinpumkong 2, and one of the phytate was the highest value of 87.5% in Dongpuktae and the lowest value of 13.9% in Hojangkong.

• Journal of Bio-Environment Control
• /
• v.18 no.1
• /
• pp.9-14
• /
• 2009

This experiment was conducted to investigate the difference among 3-years-used Polyolefin films which were J-1, J-2 and J-3 having differences in film thickness, infrared absorption and ultraviolet penetration from Jan. 16,2006. And 1-year-used Polyethylene film K-1 used from Jan. 16,2008, for covering film of greenhouse for korea melon cultivation. J-2, J-3 and J-1 films were better for keeping heat in order, and J-2 film was the best in plant growth at early stage. The first blooming and harvesting days in J-2 film were earlier 10 days than those in K-1 film. Chromaticity and soluble solid of harvested fruit in J-3, J-1 and J-2 films were higher than those in K-1 film. Marketable yields in J-2, J-1 and J-3 films were higher in order.

• Journal of Bio-Environment Control
• /
• v.19 no.3
• /
• pp.135-139
• /
• 2010

This experiment was conducted to investigate the difference among 3-years-used polyolefin films which were J-l, J-2 and J-2 having differences in film thickness, infrared absorption and ultraviolet penetration from Jan. 16, 2006. And 1-year-used polyethylene film K-1 used from Jan. 16, 2009, for covering film of greenhouse for oriental melon cultivation. J-2, J-3 and J-1 films were better for keeping heat in order, and J-2 film was the best in plant growth at early stage. The first blooming and harvesting days in J-2 film were earlier 15 days than those in K-1 film. Chromaticity and soluble solid of harvested fruit in J-2, J-3 and J-1 films were higher than whose in K-1 film. Marketable yields in J-2, J-3 and J-1 films were higher in order.

• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.9
• /
• pp.1303-1311
• /
• 2008

Twenty four early lactating Nili-Ravi buffaloes, eight in each group, were used in a Randomized Complete Block Design to evaluate the influence of varying ruminally degradable protein (RDP) to ruminally undegradable protein (RUP) ratio on feed intake, digestibility, N balance, milk yield and its composition, conception rate and days open. Three experimental diets were formulated to contain RDP:RUP of 50:50, 66:34 and 82:18 and were denoted as HRUP, MRUP and LRUP, respectively. Dry matter (DM) intake was higher (p<0.05) in buffaloes fed HRUP diet than in those fed MRUP and LRUP diets. Dry matter digestibility was higher (p<0.05) in buffaloes fed LRUP diet than in those fed HRUP and MRUP diets. Linear increase was observed in DM digestibility with increasing RDP:RUP while Neutral detergent fiber digestibility remained unaltered in buffaloes fed HRUP and MRUP diets, however, it was higher than in those fed LRUP diet. Crude protein digestibility remained unaltered across all treatments. Milk and 4 percent fat corrected milk (4% FCM) yield was higher (p<0.05) in buffaloes fed HRUP diet than those fed MRUP and LRUP diets. Linear decrease in milk yield was observed with increased RDP:RUP. Milk protein and fat yields were higher (p<0.05) in animals fed HRUP diet than those fed MRUP and LRUP diets. Milk protein percent in animals fed HRUP diet was higher than in those fed LRUP diet, whereas it did not differ with those fed MRUP diet. Percent of fat, total solids, solid not fat and lactose remained unaltered across all diets. Nitrogen balance was higher in buffaloes fed HRUP diet than in those fed other diets. Increasing the RDP:RUP resulted in a linear decrease in N balance. The blood urea nitrogen and milk urea nitrogen were lower (p<0.05) in buffaloes fed HRUP diet than those fed MRUP and LRUP diets. The blood pH remained unaltered across all treatments. Days open did not differ significantly. Conception rate was higher in buffaloes fed HRUP diet than those fed MRUP and LRUP diets. The findings of the present study indicate that feeding high (50% of the total crude protein) ruminally undegradable protein diet not only increased nutrient intake and milk yield but also improved conception rate in early lactating buffaloes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.7
• /
• pp.1064-1071
• /
• 2015

Viscous fermented red ginseng extracts were dried and coated using a fluidized bed coater to increase convenience and consumer acceptance. The methods for making spherical granules of fermented red ginseng extracts with increasing convenience were established by using indigestible dextrin. Spherical granules of fermented red ginseng extracts with increasing convenience were made by mixing indigestible dextrin at 40% (40% IDD), 50% (50% IDD), and 60% (60% IDD) versus the soluble solid content of fermented red ginseng extracts. Spherical granules of fermented red ginseng extracts showed less angle of repose than powder of fermented red ginseng extracts. This means that spherical granules of fermented red ginseng extracts had good fluency with increased convenience. The more indigestible dextrin showed higher yields. Although 50% IDD showed less yield than 60% IDD, 50% IDD was the best mixing ratio for making spherical granules of fermented red ginseng extracts, as fermented red ginseng extracts is known as a healthy food. The optimized operation conditions of the fluidized bed coater for making 50% IDD were feeding rate 0.54 mL/min, atomization air pressure 2.15 bar, and product temperature $83.03^{\circ}C$.