• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.4
• /
• pp.132-137
• /
• 2018

Although the number of chemical accidents has been declining since the Chemical Control Act of 2015, there have been repeated occurrences of similar types of accidents at printed circuit board (PCB) manufacturing facilities. These accidents were caused by the overflow of hydrochloric acid and hydrogen peroxide, which are toxic chemicals used in the printed circuit board manufacturing process. An analysis of the $Cl^-$ content to identify the cause of the accident showed that in the mixed route of hydrochloric acid and hydrogen peroxide, which are accidental substances, the $Cl^-$ concentration was 66.85 ppm in the hydrogen peroxide sample. Through reaction experiments, it was confirmed that the deformation of a PVC storage tank and generation of chlorine gas, which is a toxic gas, occurred due to reaction heat occurring up to $50.5^{\circ}C$. This paper proposes a facility safety management plan, including overcharge, overflow prevention, leak detection device, and separation tank design for mixing prevention in printed circuit board manufacturing facility etch process. To prevent the recurrence of accidents of the same type, the necessity of a periodic facility safety inspection and strengthening of the safety education of workers was discussed.

• Journal of the Korean Electrochemical Society
• /
• v.15 no.4
• /
• pp.207-215
• /
• 2012

Soft carbons are prepared by heat-treatment of cokes with different amounts of phosphoric acid (2, 4.5, and 10 wt% vs. cokes) at $900^{\circ}C$ to be used as anode materials for lithium ion batteries. From electrochemical measurements combined with structural analyses, we confirm that abundant nano-pores are existed in the microstructure of soft carbons prepared with the phosphoric acid, which are responsible for further lithium ion storage. Significant increase in reversible capacity of soft carbon is attained in proportion to added amount of the phosphoric acid. We also demonstrate the effect of structural modification with phosphoric acid on electrochemical performance of soft carbon to elucidate the origin of additional capacity.

• Korean Journal of Poultry Science
• /
• v.37 no.2
• /
• pp.173-180
• /
• 2010

This study was conducted to investigate the effects of dietary supplementation of mulberry leaves and dandelion extracts on performance, proximate composition, heating loss, drip loss, and blood characteristics of chickens. One hundred sixty broiler chicks were fed diets for five weeks containing 1% mulberry leaves extracts (T1), 2% mulberry leaves extracts (T2), 1% dandelion extracts (T3), and 2% dandelion extracts (T4). At the end of five week feeding experiment, broiler were slaughtered, and stored at $4^{\circ}C$. T2 resulted in much better weight gain and feed conversion than other treatment groups. As storage time increased, all treatment groups resulted in increased heating loss and drip loss (P<0.05) but no significant difference were observed among the treatment groups. In blood composition, GOT (glutamic oxaloacetate transaminase), GPT (glutamic pyrubic transaminase), total cholesterol, and triglyceride were significantly decreased by the supplementation of mulberry leaves and dandelion extracts compared to the control (P<0.05). Especially, T4 was significantly (P<0.05) more effective in improving blood composition compared to other treatment groups. However, no significant difference (P>0.05) were found in LDL-cholesterol among all treatment groups. In conclusion, these data indicate that compared to other treatments, supplementation of 2% dandelion extracts (T4) were most effective in decreasing total cholesterol and triglyceride and increasing HDL-cholesterol.

• Horticultural Science & Technology
• /
• v.31 no.6
• /
• pp.726-731
• /
• 2013

Experiments were conducted to evaluate the effect of low temperature-darkness treatment on floral initiation in four kinds of Korean strawberry cultivars. Mother plants were planted on March 29 and daughter plants were raised for the experiment. Temperature treatment was done for 7, 14, and 21 days keeping $13^{\circ}C$ in cooling storage from August 29, September 5 and September 14 to September 21. After the treatment, flower bud initiation was examined by a microscope, and the seedlings were transplanted on hydroponic system with Yamazaki's strawberry solution of EC $0.8dS{\cdot}m^{-1}$ to check the flowering. 'Ssanta' and 'Maehyang' showed early flower bud initiation in 7 days treatment than 'Seolhyang' by microscope check. 'Ssanta', 'Daewang', and 'Maehyang' showed early flower bud initiation in 14 days treatment than 'Seolhyang'. There were no differences among the treatments in 21 days treatment. Percentage of flowering of 'Seolhyang' and 'Maehyang' by low temperature-darkness treatment didn't show any difference but 'Daewang' and 'Ssanta' showed high percentage of flowering. It suggested that low temperature-darkness treatment technique can be use for improving early flowering and yield of 'Ssanta' and 'Daewang' cultivars.

• Applied Biological Chemistry
• /
• v.49 no.4
• /
• pp.315-321
• /
• 2006

Inhibitors of acetylcholinesterase(AchE), such as organophosphates and carbamates, interfere the action of AchE in nerve and may lead to a severe impairment of nerve functions or even death. Therefore, insect AchE is the biological target of predominant insecticides used in agriculture. Biosensors are sensitive and can be used as dispoisable sensors for environmental control. In recent years, the use of AchEs in biosensor technology has gained enormous attention, in particular with respect to insecticide detection. The principle of biosensors using AchE as a biological recognition element is based on the inhibition the catalytic activity by the agents to be detected. We here present a strip-type biosensor based on AchE inhibition. In this study, acetylcholinesterase and PVA-SbQ(polyvinyl alcohol functionalized with methyl pyridinium methyl sulfate) were co-immobilized on immobilone-P membranes. Immobilization of the enzymes showed a stability in 6 months without activity loss in $4^{\circ}C$ storage. Enzymes immobilized on surfaces of membrane responded to organophosphates and carbamate more sensitivitive than enzyme in solution. Organophosphates and carbamates concentrations could be detected by entrapped and surface immobilized enzymes, in 5 min. For chlorpyrifos, carbofuran, cabaryl, and methidathion, the detection limits of AChE-strip were similar to that of HPLC/GC method.

• Journal of Plant Biotechnology
• /
• v.7 no.3
• /
• pp.183-186
• /
• 2005

Cryopreservation has been recognized as a practical and efficient tool for the long-term storage of vegetatively propagated plants. This study was conducted to investigate the effects of slow-freezing techniques on the cryopreservation of potato. In vitro plantlets of the potato genotypes of 'Atlantic', 'Superior’, 'Namseo', 'J138', and 'CTO5-5' were cold acclimated, and the excised axillary buds were precultured, osmoprotected, exposed to plant vitrification solution, frozen slowly to $-40^{\circ}C$ and then rapidly plunged into liquid nitrogen, thawed and finally plated on the regeneration medium. It was found that the higher the sucrose concentrations in the subculture medium of donor plantlets, the higher the survival rates of shoot tips after cryopreservation, and the highest survival (20%) was observed in the medium added with 0.25 M sucrose. As for the effect of cooling, $0.3^{\circ}C/min$ cooling speed showed the highest survival (25%). Different varieties showed different responses over different cryopreservation treatments. Survival rate was increased by slow-freezing technique method as compared with that of the basic cryopreservation method of vitrification alone in the diverse potato genotypes. Leaf and tuber morphologies of potatoes regenerated after cryopreservation using slow freezing technique were similar to those derived from the in vitro stock plantlets.

• Korean Journal of Environmental Agriculture
• /
• v.36 no.2
• /
• pp.73-79
• /
• 2017

BACKGROUND: Carbonized biomass is a carbon-rich solid product obtained by the pyrolysis of biomass. It has been suggested to mitigate climate change through increased carbon storage and reduction of greenhouse gas emission. The objective of this study was to evaluate carbon dioxide ($CO_2$) and nitrous oxide ($N_2O$) emissions from soil after carbonized biomass addition. METHODS AND RESULTS: The carbonized biomass was made from a pyrolyzer, which a reactor was operated about $400{\sim}500^{\circ}C$ for 5 hours. The treatments were consisted of a control without input of carbonized biomass and two levels of carbonized biomass inputs as 6.06 Mg/ha for CB-1 and 12.12 Mg/ha for CB-2. Emissions of $CO_2$ and $N_2O$ from orchard soil were determined using closed chamber for 13 weeks at $25^{\circ}C$ of incubation temperature. It was shown that the cumulative $CO_2$ were $209.4g\;CO_2/m^2$ for CB-1, $206.4g\;CO_2/m^2$ for CB-2 and $214.5g\;CO_2/m^2$ for the control after experimental periods. The cumulative $CO_2$ emission was similar in carbonized biomass input treatment compared to the control. It was appeared that cumulative $N_2O$ emissions were $4,478mg\;N_2O/m^2$ for control, $3,227mg\;N_2O/m^2$ for CB-1 and$ 2,324mg\;N_2O/m^2$ for CB-2 at the end of experiment. Cumulative $N_2O$ emission contents significantly decreased with increasing the carbonized biomass input. CONCLUSION: Consequently the carbonized biomass from byproducts such as pear branch residue could suppress the soil $N_2O$ emission. The results fromthe study imply that carbonized biomass can be utilized to reduce greenhouse gas emission from the orchard field.

• Journal of Food Hygiene and Safety
• /
• v.32 no.5
• /
• pp.363-370
• /
• 2017

In this study, we stored frozen shrimp (Litopenaeus vannamei) at $4^{\circ}C$ during 12 days and investigated the effect of chitosan coating with natural preservatives (0.05% carvacrol, 0.05% thymol) on the growth of microorganism (mesophilic bacteria, psychrophilic bacteria, Pseudomonas spp., $H_2S$ producing bacteria) and physiological characteristics (total volatile basic nitrogen and pH) and sensory evaluation (appearance, odor and general acceptance). Chitosan coating with natural antimicrobial compounds (0.05% carvacrol and 0.05% thymol) had inhibited the growth of all the target microorganism and showed the significant antimicrobial activity (p < 0.05) to mesophilic bacteria, psychrophilic bacteria and $H_2S$ producing bacteria until 12 day (the last day of this study). These treated groups had showed the significant difference (p < 0.05) in total volatile basic nitrogen and all the sensory characteristics but not in pH. Therefore, chitosan coating combined with natural antimicrobial compounds (0.05% carvacrol and 0.05% thymol) showed the effective antimicrobial activity on major spoilage microorganism on shrimp and could be used to elongate the shelf life of refrigerated shrimp.

• Korean Journal of Food Science and Technology
• /
• v.49 no.5
• /
• pp.502-506
• /
• 2017

To improve the storage and firmness of Tteokbokki tteok Korean-style rice cakes with spicy sauce, steaming of the rice dough, soaking of the rice cake in acidic solution, and heat sterilization were conducted sequentially. The untreated control could be stored for 1 month under cold conditions, but this was extended to 10 months at room temperature ($15-30^{\circ}C$) after immersion in lactic acid solution (pH 4.0) for 20 min and heating to $100^{\circ}C$ for 30 min. The mechanical strength, which was related to firmness, was significantly increased to $11.4kgm/s^2$ compared with the untreated rice cakes ($8.8kgm/s^2$, p<0.05) and the overall descriptions of the sensory evaluation, including texture, was significantly higher than the control (p<0.05). The average size of the pores in the treated rice cakes was smaller than that of the conventional sample and the texture was improved as a result of decreased starch elution from smaller pores.

• Journal of Life Science
• /
• v.24 no.1
• /
• pp.54-60
• /
• 2014

Aromatic hydrocarbons are toxic environmental pollutants that are detrimental to the ecosystem and human health. Among them, chlorotoluene and nitrotoluene are toxic to hydrobios and irritate the skin, eyes, and respiratory organs of humans. We herein report the development of recombinant microbial biosensors for cheap and rapid monitoring of chlorotoluene and nitrotoluene compounds. Plasmids were constructed by inserting the xylR regulatory gene for BTEX (benzene, toluene, ethylbenzene, and xylene) degradation into upstream of Po' (the DmpR activator promoter Po with the deletion of its own upstream activating sequences) or Pu (the cognate promoter of XylR)::lacZ (the ${\beta}$-galactosidase gene) and transformed into Escherichia coli $DH5{\alpha}$. In the presence of inducers, the biosensor cells immobilized in agarose developed a red color in 1-2 h due to the hydrolysis of chlorophenol red ${\beta}$-D-galactopyranoside (CPRG), a substrate of ${\beta}$-galactosidase that was expressed by the inducers. Among BTEX, high responses were specifically observed with o-, m-, p-chlorotoluene ($0.1{\mu}M-100 mM$) and o-, m-, p-nitrotoluene (0.1 mM-100 mM). Po' demonstrated higher responses than those with Pu. The biosensors immobilized in agarose showed good stability after 21 days' storage at $4^{\circ}C$, and responses in untreated wastewater spiked with chlorotoluene and nitrotoluene, suggesting they can be used to detect compounds in wastewater.