• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2002.05a
• /
• pp.627-630
• /
• 2002

Bi$_2$Sr$_2$CuOx(Bi-2201) thin films were fabricated by atomic layer-by-layer deposition using an ion bean sputtering method. 10 wt% and 90 wt% ozone mired with oxygen were used with ultraviolet light irradiation to assist oxidation. XRD and RHEED investigations revealed that a buffer layer is formed at the early stage of deposition (less than 10 unit cell), and then c-axis oriented Bi-2201 grows on top of it.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.320.1-320.1
• /
• 2013

We have investigated the effect of surface passivation for crystalline silicon solar cell using ozone-based atomic layer deposited (ALD) $Al_2O_3$. We examined passivation properties such as uniformity, carrier lifetime, thickness, negative fixed charge density at AlOx/Si interface, and reflectance. The influences of process temperature and heat treatment were investigated using microwave photoconductance decay (PCD). Ozone-based ALD $Al_2O_3$ film shows the best carrier lifetime at lower deposition temperature than $H_2O$-based ALD.

• Journal of Veterinary Clinics
• /
• v.22 no.4
• /
• pp.314-317
• /
• 2005

The potential therapeutic effect of ozone gas on bovine mastitis was investigated. Eighteen quarters from 18 lactating cows with chronic mastitis were included. The 18 quarters were assigned to the control group (treatment with antibiotics for 3 days), experimental group I (0.1 ppm ozone treatment, for 7 days) and experimental group II (1ppm ozone treatment, for 3days). In experimental group I, milk somatic cell counts were lower on day 7 after ozone treatment, compared to the pretreated counts, but were higher than the control counts. In experimental group II, somatic cell counts were significantly decreased (p<0.05) on day 7 compared to the pretreatment counts, and they were lower than the control counts. There were no changes in leukocyte, neutrophil, or lymphocyte numbers, N/L ratios, N/L ratios, or serum total protein in the control and experimental groups. We concluded that ozone gas treatment(1ppm for 3days) might be effective for treatment of bovine mastitis.

• The Plant Pathology Journal
• /
• v.34 no.4
• /
• pp.335-340
• /
• 2018

To investigate the difference in the disinfectant efficiency of ozone microbubbles ($O_3MB$) and ozone millibubbles ($O_3MMB$), the morphological change of the treated Fusarium oxysporum f. sp. melonis spores was observed with scanning and transmission electron microscopies (SEM and TEM). The disinfectant efficiency of $O_3MB$ on F. oxysporum f. sp. melonis spores was greater than that of $O_3MMB$. On observation with SEM, it was revealed that morphological change of F. oxysporum f. sp. melonis spores was caused by $O_3MB$ and $O_3MMB$, and damage to the spore surfaces by $O_3MB$ occurred sooner than that by $O_3MMB$. On observation with TEM, it was furthermore confirmed that F. oxysporum f. sp. melonis spores treated with $O_3MB$ induced wavy deformation of cell membrane and the intracellular change different from that with $O_3MMB$. Therefore, the greater disinfection efficiency of $O_3MB$ was suggested to be caused due to the function of the MB in addition to the oxidative power of $O_3$.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.5
• /
• pp.533-539
• /
• 2007

Cell culture infectivity assay using HCT-8 cell was combined with most-probable-number technique to evaluate the inactivation of Cryptosporidium parvum by various disinfectants, including chlorine, ozone, and UV light. The assay was demonstrated to be as sensitive as animal infectivity assay, which has been considered the "gold standard" for assessing Cryptosporidium oocyst infectivity, and a valuable tool to evaluate inactivation of C. parvum by disinfectants. Bench-scale inactivation study showed that at the condition of $5^{\circ}C$ and pH 7.0, CT value of $1,250mg{\cdot}min/L$ by chlorine and $16mg{\cdot}min/L$ by ozone were required to achieve approximately 1.0 log inactivation of C. parvum, suggesting that even ozone could not be sufficient to inactivate C, parvum at low. temperature. Unlike chlorine and ozone, UV light is very effective to inactivate C. parvum, regardless of temperature. A UV light dose of 2 $mJ/cm^2$ provided at least 3 log inactivation of C. parvum.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2001.05a
• /
• pp.51-51
• /
• 2001

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2000.11a
• /
• pp.108-108
• /
• 2000

• Korean Journal of Food Science and Technology
• /
• v.47 no.5
• /
• pp.586-592
• /
• 2015

This study was performed to determine optimum approaches for control of microorganisms in school refectories and kitchens. A reduction of more than 5.0 log CFU/mL was noted for Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Streptococcus mutans after treatment with 5 ppm ozone water for 60 s. Treatment of different vegetables with ozone water for 5 min showed bactericidal effects with 2-4 log reduction of viable cell number; the bactericidal effects differed according to the kinds of vegetables. The viable cell number on kitchen apparatus and tableware was not detected by ozone water treatment for 60 s. In addition, the count of the bacteria floating in the air in refectories and kitchens decreased 2.0 log CFU/1,000 L air to 0-1 CFU/1,000 L air on treatment with 45 ppm ozone gas for 12 hr. Therefore, ozone water and ozone gas may be good candidates as antimicrobial agents that can be used to improve sanitary conditions in school refectories and kitchens.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.22 no.2
• /
• pp.165-174
• /
• 1993

This work was conducted to study the use of L. acidophilus, which exists in humun intestine for the fermentation of Chinese cabbage kimchi. The changes in vitamins, the number of microflora and sensory quality were observed during fermentation after the microflora which was not related to kimchi fermentation was eliminated by treatment with ozone water or ozone gas. The growth rate of L. acidophilus in the cabbage juice was higher than that in MRS broth. The growth of L. acidophilus was slightly promoted by adding 1~2% hot pepper powder while that was inhibited by ginger and garlic. Therefore, it was shown that the regulation of fermentation was possible by addition of spices. The result of treating spice with ozone gas and ozone water 6mg/L/sec for 1 hour was that the survival ratio of total microflora was 6~20%. When L. acidophilus was added to materials after ozone treatment, the fermentation rate was improved and the polysaccharides in the cell wall were used when the usable free sugar was all consumed. The contents of vitamin B$_1$ and C in the ozone treated kimchi was higher than in the control.

• Journal of Life Science
• /
• v.16 no.3 s.76
• /
• pp.534-539
• /
• 2006

In the ozone disinfection unit process of a piston type batch reactor with continuous ozone analysis using a flow injection analysis (FIA) system, the CT values for 1 log inactivation of Cryptosporidium parvum by viability assays of DAPI/PI and excystation were $1.8{\sim}2.2\;mg/L{\cdot}min$ at $25^{\circ}C$ and $9.1mg/L{\cdot}min$ at $5^{\circ}C$, respectively. At the low temperature, ozone requirement rises $4{\sim}5$ times higher in order to achieve the same level of disinfection at room temperature. In a 40 L scale pilot plant with continuous flow and constant 5 minutes retention time, disinfection effects were evaluated using excystation, DAPI/PI, and cell infection method at the same time. About 0.2 log inactivation of Cryptosporidium by DAPI/PI and excystation assay, and 1.2 log inactivation by cell infectivity assay were estimated, respectively, at the CT value of about $8mg/L{\cdot}min$. The difference between DAPI/PI and excystation assay was not significant in evaluating CT values of Cryptosporidium by ozone in both experiment of the piston and the pilot reactors. However, there was significant difference between viability assay based on the intact cell wall structure and function and infectivity assay based on the developing oocysts to sporozoites and merozoites in the pilot study. The stage of development should be more sensitive to ozone oxidation than cell wall intactness of oocysts. The difference of CT values estimated by viability assay between two studies may partly come from underestimation of the residual ozone concentration due to the manual monitoring in the pilot study, or the difference of the reactor scale (50 mL vs 40 L) and types (batch vs continuous). Adequate If value to disinfect 1 and 2 log scale of Cryptosporidium in UV irradiation process was 25 $mWs/cm^2$ and 50 $mWs/cm^2$, respectively, at $25^{\circ}C$ by DAPI/PI. At $5^{\circ}C$, 40 $mWs/cm^2$ was required for disinfecting 1 log Cryptosporidium, and 80 $mWs/cm^2$ for disinfecting 2 log Cryptosporidium. It was thought that about 60% increase of If value requirement to compensate for the $20^{\circ}C$ decrease in temperature was due to the low voltage low output lamp letting weaker UV rays occur at lower temperatures.