• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.33-41
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• 2021

Recently, many studies have been conducted on substituting fossil fuels with bio-refineries in existing industrial systems using biomass. Among the various bio-refineries, microalgae have received wide attention because it uses inorganic compounds to produce useful substances, which are extracted by a cell disruption process. Although numerous cell disruption methods exist, cell disruption efficiency has been studied by ultrasonic treatment. Ultrasound is a high-frequency (20 kHz or higher) sound wave and causes cell disruption by cavitation when passing through a solvent. In this study, we used the microalgal species Chlorella sp., which was cultured in a plate-type photobioreactor. The experiment was conducted using a continuous low-frequency processing device. The reduction of cells with time due to cell disruption was fitted using a logistic model, and optimum conditions for highly efficient cell disruption were determined by conducting experiments under multiple conditions.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.5
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• pp.362-367
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• 2005

Ultrasonic backward radiation profile is frequency-dependent when the incident region has deptional gradient of acoustical properties or multi-layers. Until now, we have measured the profiles of principal frequencies of an used transducers so that it was not easy to characterize the frequency dependence of the SAW(surface acoustic wave) from the backward radiation profile. We tried to measure the spectral backward radiation profiles using DFP(digital filer package) in a Lecroy DSO(digital storage oscilloscope). The measured spectral profiles showed that the steel specimen of #1200 surface treatment have 2% SAW velocity dispersion of the loaded case and the severly rusty steel specimen have the very big changes in the shape and pattern of the spectral profile. It is concluded that the spectral backward radiation profiles could be very effective tool to evaluate the frequency dependence of surface area.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.3
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• pp.29-37
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• 2017

Purpose: The purpose of this study was to classify patients with chronic back pain according to the degree of their back pain, and to compare the pain dysfunction index with the qualitative changes in abdominal muscles. Therefore, we aimed to provide a basis for the treatment intervention method for patients with back pain. Methods: Twenty patients with chronic back pain were purposive sample to a group of 10 patients with a back pain index of 60 % or more and a group with less than 60 % of back pain, and the subjects who voluntarily participated in the study After receiving the letter, I conducted the research the dysfunction of back pain was measured by the Korean version of the Oswestry Disability Index (KODI), and the ultrasonic wave (Ultrasound MyLabOne, ESAOTE, Italy) And the white area index, and the abdominal muscle movement was used as the exercise instrument POWER breathe K5 (Hab direct, UK), which strengthens the respiratory muscles through threshold-muscle traction. Result: In this study, patients with chronic back pain were subjected to breathing exercises, which led to the decrease in back pain dysfunction. The ultrasonographic analysis of abdominal muscles revealed that both the white area index and muscle image density in the skeletal muscle and in the outer muscle of the abdomen gradually decreased over time. Conclusion: It is thought that introducing back pain patients to abdominal muscle reinforcement training is effective in improving the functions of the patients' muscles, thus increasing their quality of life.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.937-942
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• 2013

Fluid generated within the sonic or ultrasonic waves are reflected by the wall, while the opposite direction forming a predetermined sound wave to the acoustic standing wave is referred to. In this study, the frequency of 1.0 MHz and 2.0 MHz acoustic standing wave generation module is installed in a continuous particle separation device, the laminar flow of influent, taking into account the hydraulic retention time (HRT) in accordance with changes in particle separation characteristics investigated. Operation of a standing wave in the particle separation device about $1.3{\sim}2.8^{\circ}C$ temperature is increased, but did not significantly affect the formation of standing waves. During operation, the HRT 1 hr frequency 1.0 MHz 2 hr, 4 hr longer as the particle separation efficiency (turbidity) were 64.1%, 70.0%, 74.3% and, 2.0 MHz has 58.0%, respectively, depending on HRT, 61.8%, 70.7% in the respectively. That is, the same frequency, the HRT treatment efficiency is 10% or more, depending on differences in generation and, 1.0 MHz frequency, 2 hr, 2.0 MHz 4 hr at about 70% or more of the processing efficiency can be maintained. Frequency of 1.0 MHz and 2.0 MHz operation at the same time, as a result, HRT 1 hr, 2 hr, 4 hr particle separation efficiency of 63.8%, respectively, 70.6%, 77.6%, rather than the generation of standing waves appear continuous HRT is affecting a lot of particles to separate could know.

• Korean Journal of Agricultural Science
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• v.2 no.2
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• pp.451-462
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• 1975

The qualities of the grape wines brewed with the varieties of Steuben, Muscat Bailey A, Merlot, Campbell Early and Alden were compared, and studied the mashing methods of the wine with a variety of Muscat Bailey A. and then investigated the aging effects of ultrasonic wave and the baking treatments on the new wines. The results obtained were as follows. 1. Extracts of the new wines brewed with the varieties of Steuben and Alden were 2.55 and 1.88 per cent respectively and the color densities of the wines with Merlot and Alden were 3.5 and 1.05 (optical density) respectively, and the other contents were not significantly different beween varieties. On the Otherhand, the results of sensory test showed that the order of favorite was the wines brewed with Steuben, Muscat Bailey A, Merlot, Campbell Early and Alden. 2. The effect of pasteurization ($55^{\circ}C$, 20 min.) on the inhibition of the growth of undesirable microorganism was appeared almost the same degree as the case of sulfiting (100 ppm), and the pasteurized must was more dense in color but slightly turbid than the case of sulfiting. 3. Glucose syrup was in adequate as a materials for supplemental sugar, and the quality of the new wine further fermented the free-run wine added the alcohol to be a constant alcohol content was almost the same as that of control. 4. Baking at $50^{\circ}C$. for 50 days to t he new wine from 0.45 to 0.65 per cent, and color density was also thicken from 2.8 to 3.17 (O. D). 5. Baking at $40^{\circ}C$. for 50days to the new wine brewed with Muscat Bailey A, increased the ester content of the wine from 0.37 to 0.65 per cent and color density was-also thicken from 3. to 4.2 (O.D). 6. Ultrasonic wave (150 watt, 20Kc) treatment for 10 hours to the new wine brewed with Muscat Bailey A, increased the ester content of the wine from 0.37 to 0.47 per cent.

• Journal of Food Hygiene and Safety
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• v.24 no.2
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• pp.174-181
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• 2009

The consumption of "ready-to-eat" agricultural products is recently increasing and the safety of these agricultural products is forefront of public concerns. The 120 samples of paprikas, strawberries and tomatoes, which are the representative exported agricultural products, were purchased at the department stores and discount stores in Daejeon. And we determined the microbiological and parasitological contamination level of these agricultural products using culture media, multiplex PCR, commercial bacterial detection kit and microscopy, and also evaluated the decontamination method. Mean counts of total aerobic bacteria from these agricultural products ranged from $1.3{\times}10^4$ CFU/g to $1.8{\times}10^5$ CFU/g, and mean counts of coliforms ranged from $1.4{\times}10^3$ CFU/g to $9.6{\times}10^3$ CFU/g. There was no significant difference in the level of bacterial contamination between the agricultural products from department stores and the ones from discount stores. Strawberry showed the highest contamination level for the bacteria and we also found the unidentified parasite eggs. Enterobacter cloacae was the most frequently isolated bacteria strain, but no food poisoning pathogenic bacteria except Staphylococcus aureus was isolated from the products by multiplex PCR. Compared to unwashed products, tab water-washed ones showed 80% decrease of the counts of total aerobic bacteria on the agricultural products, and the rates decreased more by incorporating detergent or ultrasonic wave treatment. We concluded that the biological contamination levels among paprikas, strawberries and tomatoes were the highest in strawberries, but there were not significant difference according to distribution systems.