• Preventive Nutrition and Food Science
• /
• v.9 no.2
• /
• pp.121-125
• /
• 2004

Effects of chemical treatment with a citric acid solution or ozonated water on microbiological changes in lettuce and cabbage during storage were studied. Fresh lettuce and cabbage samples were cut into small pieces and treated by soaking in either ozonated water or a citric acid solution. After treatment, populations of total bacteria, yeast and mold, and E. coli were determined. Numbers of microorganisms increased during storage, but ozonated water and citric acid treatments retarded the increase in microbial growth. Among treatments, 1 % citric acid treatment was the most effective in terms of microbiological change and inhibition of polyphenoloxidase (PPO). For lettuce, citric acid treatment decreased the microbial growth overall by 1.5 log CFU/g and inhibited the PPO activity by 80%. These results indicate that chemical-treated lettuce and cabbage retained a better quality than those of the control during storage.

• Journal of Sensor Science and Technology
• /
• v.26 no.5
• /
• pp.360-365
• /
• 2017

In this study, a heat treatment process was applied to ZnS nano-powder to improve the optical properties of ZnS ceramic, and the characteristics of heat treatment time were studied. The ZnS nano-powders were synthesized by hydrothermal synthesis. The heat treatment was carried out at $550^{\circ}C$ for 0.5, 1, 2, and 4 hours in a vacuum atmosphere ($10^{-2}torr$). X-ray diffraction and scanning electron microscope analyzes confirmed the change of crystal phase and grain size to confirm the structural change with heat treatment time. The heat treated ZnS nano-powder was sintered by hot pressing, and the change of optical properties of the ZnS ceramic was analyzed by infrared spectroscopy.

• Food Science and Preservation
• /
• v.30 no.2
• /
• pp.190-204
• /
• 2023

Because of their short harvest season, large quantities of persimmons must often be processed within a limited time. Therefore, new methods to extend their storage life are required. This study examined the effects of chlorine dioxide (ClO₂) gas fumigation for various treatment periods on the storage quality of astringent persimmons Cheongdobansi under low-temperature conditions. The conditions consisted of continuous treatment with ClO₂, treatment for 2 weeks with ClO₂, and no treatment, all of which are stored at low temperatures. Control samples (storage 0 days) without any treatment were prepared and all experiments were conducted for 10 weeks at two-week intervals. The ClO₂ gas treatment maintained the moisture content, color value, hardness, soluble tannin content, and sensory characteristics. However, ClO₂ gas treatment did not affect the soluble solids, pH, and total sugar content. In particular, continuous treatment with ClO₂ maintained the storage quality after 6-8 weeks of storage, particularly the hardness and weakness (sensory evaluation). The results suggest the potential of continuous treatment with ClO₂ as a highly effective method for maintaining the freshness of Cheongdobansi.

• Journal of Technologic Dentistry
• /
• v.35 no.4
• /
• pp.395-403
• /
• 2013

Purpose: This article examined the affecting factors of a malocclusion status of a patient for orthodontic treatment, orthodontics medical expenses and oral health behavior on orthodontic satisfaction. Methods: This paper conducted a survey from the 15th of July to 30th of September 2012 for the patients who were under orthodontic treatment at three dental clinics where are in Deagu, and distributed a total of 210 questionnaires and analyzed 194 questionnaires, excepting for some questionnaires that were answered unfaithfully. Results: This study classified the related factors into a feeling of satisfaction with treatment and mental satisfaction for finding orthodontic satisfaction. There were the effect of the right tooth-brushing method, a periodic scaling and orthodontics medical expenses on a feeling of satisfaction with treatment, and power of explanation was 16.7%. Conclusion: There were the effect of a malocclusion status, matters that requires attention during orthodontic treatment, a periodic scaling during orthodontic treatment and orthodontics medical expenses on mental satisfaction, and power of explanation was 16.9%. Based on the result above, this paper concluded that preventive treatment and early treatment should be emphasized through developing a program for regular oral examination suited to each medical type, including the method for improving the medical treatment condition and care service for increasing orthodontic satisfaction, which the dental medical-service providers could consider the patients and secure trust.

• Journal of Institute of Convergence Technology
• /
• v.5 no.1
• /
• pp.13-17
• /
• 2015

In wafer level molding progress, the thermal releasing failure phenomenon is shown up as the important problem. This phenomenon can cause the problem including the warpage, crack of the molded wafer. The thermal releasing failure is due to the insufficiency of adhesion strength degradation of the molding tape. To solve this problem, we studied experimental method increasing the release property of the molding tape through the plasma surface treatment on the wafer substrate. In this research, the vacuum plasma treatment system is used for release property improvement of the molding tape and controls the operating condition of the hydrophilic($O_2$, 100kW, 10min) and hydrophobic($C_2F_6$, 200kW, 10min). In order to perform the peeling test for measuring the releasing force precisely, we remodel the micro scale material property evaluation system developed by Korea institute of industrial technology. In case of hydrophilic surface treatment on the wafer substrate, we can figure out the releasing property of molding tape increase. In order to grasp the effect that it reaches to the release property increase when repeating the hydrophilic treatment, we make an experiment with twice treatment and get the result to increase about 12%. We find out the hydrophilic surface treatment method using plasma can improve releasing property of molding tape in the wafer level molding process.

• Journal of Korean Society of Water and Wastewater
• /
• v.31 no.4
• /
• pp.297-301
• /
• 2017

Wastewater treatment using ferrate (VI) solution is becoming a promising technology for several years, because it is high efficient and harmless technology. In this study, the ferrate (VI) solution was tested to treatment of desulfurization wastewater. The effluent from desulfurization wastewater treatment process of power plant was used as raw water, and the COD and T-N removal efficiency of ferrate(VI) solution were investigated. In the test, as the injection rate increased from 0.1 to 1.0%, the removal efficiency of COD also slightly increased, about 80% of COD were removed in 1.0% of injection rate. In the case of T-N, about 50% of T-N was removed in the condition of 1.0% of injection rate. The removal efficiency of COD and T-N also affected by reaction time, maximum removal efficiency was shown in 30 min of treatment. From these results, the wastewater treatment with ferrate(VI) solution can be great solutions for treatment of non-biodegradable pollutants in wastewater, especially for the 3rd treatment of wastewater.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.8
• /
• pp.1240-1247
• /
• 2019

This study was conducted to examine the inactivation effect of the combined treatment of high hydrostatic pressure (HHP; 400 MPa for 1, 3, and 5 min) and cationic surfactant washing (0.05% benzethonium chloride, BEC) against Listeria monocytogenes inoculated on fresh-cut broccoli (FCB). Washing with BEC at concentrations exceeding 0.05% resulted in 2.3 log-reduction of L. monocytogenes counts on FCB, whereas HHP treatment had approximately 5.5-5.6 log-reductions regardless of the treatment time. Scanning electron microscopy corroborated microbial enumeration, revealing that the combined treatment was more effective in removing L. monocytogenes from FCB than individual treatment with HHP or BEC. Color and total glucosinolate content were maintained after the combined treatment, although the hardness of the FCB slightly decreased. The results clearly suggest that the combined treatment of HHP and BEC washing has potential value as a new sanitization method to improve the microbial safety of FCB.

• Transactions of the Korean hydrogen and new energy society
• /
• v.14 no.1
• /
• pp.1-7
• /
• 2003

In this study, activity changes of $Ni/Ce-ZrO_2$ catalyst for steam reforming reaction in the various steam treatment condition were investigated and BET, XRD and XPS analysis were introduced to characterize the catalyst before and after treatment. Activity test showed that $Ni/Ce-ZrO_2$ catalyst had good activity after reduction in steam reforming reaction but deactivated rapidly after steam treatment at high temperature. Activities of deactivated catalyst by steam was recovered to die previous activity level after reduction using hydrogen rich gas. It was observed that catalytic activity was preserved after repeated steam treatment, too. It showed that change of catalytic activity due to steam treatment is perfectly reversible. From the BET, XRD and XPS analysis, deactivation of $Ni/Ce-ZrO_2$ catalyst was due to the transition from Ni, that is activity site for steam reforming reaction, to $NiAl_2O_4$ in steam treatment at high temperature.

• Journal of the Korean Society for Heat Treatment
• /
• v.6 no.4
• /
• pp.185-193
• /
• 1993

The effect and Condition of heat treatment on the tensile strength of welded joint was investigated in 300 grade 18% Ni-Co-Mo-Ti maraging steel sheets welded with electron beam. A good tensile strength of welded joint was obtained by following heat treatment cycle ; At $1100^{\circ}C$ the specimen was high temperature solution treated for 1 hour and then it was repeated solution treated at $900^{\circ}C$, $820^{\circ}C$ for 1 hour respectively to recrystallize the coarsened ${\gamma}$ grain. These heat treatment cycle was completed by an final aging heat treatment at $480^{\circ}C$ for 4 hour. Moreover, dissolution of dendrite, a significant decrease in seregation of Mo, Ti in weld metal were observed and also the coarsened ${\gamma}$ grain formed at $1100^{\circ}C$, $1200^{\circ}C$ changed to fine grain due to the effect of recrystallization.

• Design & Manufacturing
• /
• v.17 no.1
• /
• pp.40-47
• /
• 2023

Macular degeneration and glaucoma are representative age-related retinal diseases that rank second and third in the prevalence of retinal diseases, and are a kind of degenerative neurological disease. Irreversible visual acuity and visual field damage may occur, and the number of patients is rapidly increasing as the population ages. Since this retinal disease is a chronic disease, continuous drug treatment is required. There are various drug delivery methods for treatment, but direct injection of the drug into the intravitreal is the most effective for continuous delivery of the drug over a long period of time. In order to solidify Dexamethasone, a retinal disease treatment, and insert it into the primary intravitreal, it is important to develop a technology to miniaturize the treatment and an applicator to deliver the treatment. In this study, a mold technology was developed to integrate the cannula and hub, which are one part of applicator. In addition, surface treatment was performed on the outside of the cannula to improve the bonding strength between the cannula and the hub, and the bonding strength according to each condition was analyzed through a tensile test.