• Korean Journal of Microbiology
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• v.11 no.1
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• pp.19-30
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• 1973

The sweet potatoes infected with witches'-broom disease were collected in the growing fields in Jeon-bug area, Korea. As a possible control plant, Ipomoea batatas L.var. Suwon 147 was selected. The pathogen was identified by various methods ; such as mechanical transmission, antibiotic reactions and electron microscopy. In the results attained the author believed the pathogen of the sweet potato infected with witches' broom to be a mycoplasma-like organism. the results are as follows : 1. Mycoplasma-like bodies were occurred in the phloem region of the sweet potatoes infected with witches'-broom and its particles were sized in the range of about 200-2,500m.mu.. The membrane of the pathogen was observed to be made of an unit. 2. Responsibilities to the antibiotices were sensitive in case of tetracycline and terramycin, and root dipping method showed remarkable than foliage spray. 3. The infection was developed by the grafting transmission but by the insects, Myzus persicae and Cicadella viridis. 4. rosette, witches'-broom, stunt, yellowish, mosaic and necrosis were observed as the symptomps of the disease.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.168-169
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• 2013

In this study, the chemical resistance of polyurea resin waterproofing and anti-corrosion materials that is applied to the social infrastructure was analyzed. The result in this study will be utilizing as a basic data for establishing the quality standards which are able to judge the chemically resistant characteristic of polyurea resin waterproofing and anti-corrosion materials.

• Korean Journal of Organic Agriculture
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• v.21 no.2
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• pp.265-270
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• 2013

Cooking oil and yolk mixture (COY) was applied to control the powdery mildew of sweet persimmon at the research field of Gyeongsangnam-do Agricultural Research and Extension Services from 2010 to 2011. COY was sprayed three times with 10 days interval on foliar parts of sweet persimmon and the disease development was monitored after 5 days of final spray. Diseased leaf area rate was 13.4% and the control efficacy of COY against powdery mildew was 80.5%. Disease rate was 68.6% on negative control. Using scanning electron microscope (SEM), the morphological changes of the powdery mildew fungus on the leaf surface were observed. On COY-treated leaves, fungal mycellia were morphologically characterized by a loss in cell volume, shriveling, plasma membrane rupture, and subsequent loss of intracellular contents. It may due to the destruction of fungal cell wall or membrane structure.

• Journal of ILASS-Korea
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• v.19 no.3
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• pp.142-148
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• 2014

In this study, characteristics of gaseous pollutants and particulate matter were investigated on the condition of DPF regeneration and normal DPF condition. THC, CO, $CO_2$, NOx, and $CH_4$ were analyzed by MEXA-7200H and CVS-7100 respectively. Particulate Matter (PM) was measured by difference in weight of Membrane filter. Particle Number (PN) was measured by CPC analyzer. And Sulfate, Nitrate, Organic were measured by Aerosol Mass Spectrometer (AMS). As a result, gaseous pollutants and particulate matter were detected in higher concentration during DPF regeneration than normal DPF condition. And the PN increased by 94%, the fuel consumption was reduced by 29% on DPF generation process. Sulfate, Nitrate and Organic were undetectable level during normal DPF condition. But the highest concentration of Sulfate, Nitrate and Organic were measured as $100{\mu}g/m^3$, $20{\mu}g/m^3$ and $15{\mu}g/m^3$ respectively on DPF regeneration condition. VOCs concentrations (Benzene, Toluene, Ethylbenzene, Xylene) were analyzed by using PTR-MS. Benzene and Toluene emission have little or no change depending on DPF regeneration. But the Ethylbenzene and Xylene have comparatively low emissions on DPF regeneration.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.85-92
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• 1984

The aim of this study was to examine the influence of the speed of grinding and coolants on mercury vaporization during amalgam removal. Forty amalgam filled stone dies were stored at $37^{\circ}C$ and 100% relative humidity for 7 days prior to the beginning of the mercury vapor experiment and were divided into 4 different groups; In Group I; Used by high speed without coolant & evacuator during amalgam removal. In Group II; Used by high speed with coolant & evacuator during amalgam removal. In Group III; Used by low speed without coolant & evacuator during amalgam removal. In Group IV; Used by low speed with coolant & evacuator during amalgam removal. The amalgam specimens were removed in a 30-second time period and mercury vapor was collected with membrane filter at 27mm from the site of removal and 45 degree above there. Samples in Group II, IV were removed with coolant spray at a flow rate of 30 ml/min with high-velocity evacuator. Mercury vapor collected membrane filter was analysed by Atomic Absorption Spectrophotometer using cold vapor method. The results were as follows; 1. The mercury vapor levels were obtained all of the Groups. 2. The mercury vapor levels of the Group II, IV (with coolant & evacuator) were less than that of the Group I, III (without coolant & evacuator). 3. The highest mercury vapor level recorded during amalgam removal procedure was Group I (used by high speed without coolant & evacuator) and its record was $0.78{\pm}0.09\;mg/m^3$, which exceed the T.L.V. by 15 times. 4. The mercury vapor level of the Group IV (used by low speed with coolant & evacuator) was more than that of the Group II (used by high speed with coolant & evacuator), but its difference was not significant, statistically. (p > 0.05)

• Food Science of Animal Resources
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• v.33 no.2
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• pp.229-238
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• 2013

Lactic acid bacteria (LAB) are added to different food products for a long time due to health beneficial effects on human host. LAB is applied in dairy products, such as yoghurt, cheese, and various fermented products, and also in non-dairy products, such as sausages. However, reaching the human gut alive as well as in a sufficient cell amount to exert positive health effects is still a big challenge, due to LAB sensitive character and vulnerability against harsh and detrimental conditions in human digestive system. Keeping physiological activity of sensitive LAB strains alive is for the formulation of novel food products with a probiotic health claim of utmost interest, thus microencapsulation has been applied and investigated as a promising technique for a good and reliable protection. Microencapsulation allows reduced cell injury or cell loss by retaining cells within the encapsulating membrane and can be enforced by spray-drying, emulsion, extrusion, and a range of other technologies in combination with an appropriate coating material, such as alginate, chitosan, and mixture of these two polymers. In this review, established and well-studied microencapsulation techniques with their favored coating materials, as well as the recent applications of microencapsulated LAB into dairy products will be discussed.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.6
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• pp.523-530
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• 2019

For the low-Pt electrodes for polymer electrolyte fuel cells (PEMFCs), the optimization of ionomer content for anode catalyst layers was carried out. A commercial catalyst of 20 wt.% Pt/C was used instead of 50 wt.% Pt/C which is commonly used for PEMFCs. The ionomer content varies from 0.6 to 1.2 based on ionomer to carbon ratio (I/C) and the catalyst layer is formed over the electrolyte by the ultrasonic spray process. Evaluation of the prepared MEA in the unit cell showed that the optimal ionomer content of the air electrode was 0.8 on the I/C basis, while the hydrogen electrode was optimal at the relatively high ionomer content of 1.0. In addition, a large difference in cell performance was observed when the ionomer content of the hydrogen electrode was changed. Increasing the ionomer content from 0.6 to 1.0 by I/C in a hydrogen electrode with 0.05 mg/㎠ platinum loading resulted in more than double cell performance improvements on a 0.6 V. Through the analysis of various electrochemical properties in the single cell, it was assumed that the change in ionomer content of the hydrogen electrode affects the water flow between the hydrogen and air electrodes bounded by the membrane in the cell, which affects the overall performance of the cell. A more specific study will be carried out to understand the water flow mechanism in the future, and this study will show that the optimization process of hydrogen electrode can also be a very important cell design variable for the low-Pt and high-performance MEA.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.205-208
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• 2014

Here, we reported mass-produced organic nanowires with uniform sizes based on poly(9,9-dioctylflurorene) (PFO), poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT), (regioregular poly(3-hexylthiophene) (P3HT) which are well known as organic semiconductors for opto/electronics applications, using a melt-assisted wetting method with anodic alumina membrane. The conjugated polymer nanowires showed uniformed diameters (D=250~300 nm) and lengths ($L={\sim}30{\mu}m$) with defect free smooth surface regardless of a kinds of semiconductors. In addition, the nanowires were uniformly deposited onto glass substrates by spray-coating method. Under the UV light irradiation, PFO and F8BT nanowires showed blue and yellow emissions, respectively.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.329-336
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• 2014

As an abiotic stress, chilling stress is one of the major factors limiting plant growth and increasing susceptibility to pathogens. Therefore, enhancing stress tolerance in plants is an important strategy for their survival under unfavorable environmental conditions. The objective of this study was to determine the effects of the exogenous application of salicylic acid (SA) or nitric oxide (NO) on chilling tolerance in pepper seedlings. Pepper (Capsicum annuum L. 'kidaemanbal') seedlings were grown under normal growing conditions ($20/25^{\circ}C$, 15 hours photoperiod, $145{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, fluorescence lamps) for 23 days after transplanting. The solution (3 mL) of 1 mM SA and 0.3 mM NO with surfactant triton 0.1% were sprayed two times a week, respectively. Right after the completion of chemical application, seedlings were subjected to chilling condition at $4^{\circ}C$ for 6 hours under dark condition and then the seedlings were recovered at the normal growing conditions for 2 days. In order to assess plant tolerance against chilling stress, growth characteristics, chlorophyll fluorescence (Fv/Fm), and membrane permeability were determined after chilling stress imposition. Total phenolic concentration and antioxidant capacity were measured during the whole experimental period. Disease incidence for pepper bacterial spot and wilt was also analyzed. Pepper seedlings treated with SA or NO were maintained similar dry mass ratio, while the value in control increased caused by chilling stress suggesting relatively more water loss in control plants. Electrolyte leakage of pepper seedlings treated with SA or NO was lower than that of control 2 days after chilling treatment. Fv/Fm rapidly decreased after chilling stress in control while the value of SA or NO was maintained about 0.8. SA increased higher total phenolic concentration and antioxidant capacity than NO and control during chemical treatment. In addition, increase in total phenolic concentration was observed after chilling stress in control and NO treatment. SA had an effect on the reduction of bacterial wilt in pepper seedlings. The results from this study revealed that pre-treatment with SA or NO using foliar spray was effective in chilling tolerance and the reduction of disease incidence in pepper seedlings.