• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.54-61
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• 1999

A study was conducted to find a rapid thawing method which prevents excessive drip loss and local overheating. Effects of thawing methods (conventional thawing vs. 2,450 and 915 MHz microwave thawing) on thawing time, temperature profile, drip loss, water holding capacity, total color difference and total aerobes were investigated. Samples were thawed at 4, 28 and $50^{\circ}C$ in a refrigerator or an oven for the conventional thawing methods the convertional thawing methods. Power levels of 5, 10 and 15 kW were used for 915MHz microwave thawing. Cotreatment of 915 MHz microwave and convectional heating $(120^{\circ}C)$ was tested. 915 MHz microwave accelerated the thawing rate, and showed significant effects on penetration depth, drip loss, water holding capacity and total aerobes. Cotreatment of 915 MHz microwave and convection heating was appeared to be a suitable thawing process for the food industry.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.173-177
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• 1986

Since March 1985, we have treated cancer patients with local hyperthermia using a 2,450-MHz microwave thermogenerator. Prior to clinical trial, a 2,450-MHz microwave generator remodeled from a household electric range was tested and evaluated to test its clinical applicability. We studied the thermoprofile and tried to find out suitable electric power ranges to produce optimal temperature of $42-44^{\circ}C$ in a lump of meat, agar phantom and animal tumor models. The present study confirmed the intratumoral temperature to be $1-3^{\circ}C$ higher than in surrounding normal tissue.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.4
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• pp.353-362
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• 1996

In this paper, SAR distribution is calculated according to the rabbit's head using approximation of its medium three layers model. Our experiment was classified 5 groups dependent on the power intensity of 2,450MHz microwave to measure EEG(Electroencephalograph) of rabbit, which was checked in left frontal lobe before and after irradiation of microwave. In results, mean total power of EEG was slightly decreased and mean composition percentages of $\theta$, $\delta$ and $\beta$ wave were increased after irradiation in observation. It means to decrease of elect- rophysiologic activity and trend of fast wave in brain after irradiation of its microwave. We analyzed the electrophysiological effect of the biobody quantitatively using measured EEG and estimated MPE (Maximum Permissible Exposure).

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1130-1136
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• 2006

This work elucidates the effects of pretreatment of the sewage sludge from wastewater treatment plant by microwave irradiation on elutriated acid fermentation. These experiments typically fell into two process; pretreatment as microwave irradiation and elutriated acid fermentation for hydrolysis and acidification as main process of primary sludge. The results of maximum solubilization rate of B, D primary and secondary sludge were 0.042, 0.086 and 0.15 gSCODprod./gICODin and the optimum irradiation time of microwave on 2,450 MHz and 900 W were 5 min. for primary sludge and 7 min. for secondary sludge. From batch tests on elutriated acid fermentation that was used the pretreated primary sludge as microwave, the optimum pH and HRT (hydraulic retention time) were 7 and 5 days at $35^{\circ}C$ condition.

• Food Science and Preservation
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• v.12 no.2
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• pp.146-150
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• 2005

A comparative study of pretreatment and extraction methods was conducted to investigate their effects on nutritional and bioactive components during hot-water extraction of Acanthopanax senticosus. The herb samples, ground and sifted $(8\~20\;mesh)$ were pretreated with ultrasound (20 kHz), microwave (2,450 MHz) or roasting $(180^{\circ}C)$ for 10 min, and then extracted by a boiling $(180^{\circ}C)$ under atmospheric pressure or a pressured boiling $(121^{\circ}C)$ for 2 hr. In general, the pretreatments improved the extraction efficiency and the DPPH radical scavenging activity of extract. Particularly, the extraction yields of soluble solids, total sugar and phenolic compounds were increased in microwaving methods, and the protein yield and the radical scavenging activity were higher in roosting pretreatment. Yields of soluble solids, total sugar, protein and phenolic compouds in pressured extraction were higher than those in nonpressured extraction. These results suggested that pretreatment including microwave radiation, sonication and roasting and pressured extraction can be utilized for improving the extraction efficiency of A. senticosus.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.737-742
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• 2012

To evaluate efficacy of microwave ablation in a primary clinical study, sixty patients (44 men, 16 women; mean age 53 years) with 96, 1-8 cm (mean $3.20{\pm}0.17$ cm) liver cancers were treated with 2,450-MHz internally cooled-shaft antenna. Complete ablation (CA) and local tumor progression (LTP) rates as well as complications were determined. CA rates in small (< 3.0 cm), intermediate (3.1-5.0 cm) and large (5.1-8.0 cm) liver cancers were 96.4% (54/56), 92.3% (24/26) and 78.6% (11/14), respectively. During a mean follow-up period of $17.17{\pm}6.52$ months, LTP occurred in five (5.21%) treated cases. There was no significant difference in the CA and LTP rates between the HCC and liver metastasis patient subgroups (P<0.05). Microwave ablation provides a reliable, efficient, and safe technique to perform hepatic tumor ablation.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.323-327
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• 2000

Microwave-assisted process (2,450MHz), which is known as a more environmental-friendly process with economic advantages than the current extraction methods, was investigated to pre-establish the extraction conditions for soluble ginseng components used for the processing of ginseng products. The extractions of soluble ginseng components showed optimum conditions, such as 60 mesh in particle size, 1 : 10 (g/mL) in the sample to solvent ratio, and less than 100 watts in energy efficiency. Under these conditions using along with 60% ethanol for 5 min, the overall yield of ginseng extracts was about 83%. Most soluble components including saponins were extracted by repeating five times of microwave-assisted extraction.

• Food Science and Preservation
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• v.7 no.3
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• pp.273-277
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• 2000

Some fundamental conditions were investigated in microwave-assited extraction (MAE) for oleoresin from Chinese dried ginger. The fifty watts of microwave energy(2,450 MHz), 60 mesh in particle size and 1:10 (g/mL) ratio of sample to solvent were the optimum conditions. Lower yield of soluble oleoresins was obtained at higher concentrations of ethanol. Radical scavenging ability was highest in extracts by using 25% of ethanol. Total phenolics in extracts were remarkably increased at above 50% of ethanol concentration. Overall yield of oleoresin components increased in proportional to extraction time up to 7 min. Based on the above results, it is indicated that ethanol concentration is a critical parameter in MAE.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.25-32
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• 2001

A microwave vacuum (MW/V) dryer was developed for drying short roundwoods, from which woodcraft souvenirs in Korean market are mostly made, and which were hardly dried without defects in a conventional kiln. It consisted of three 1.5 kW magnetrons of 2,450 MHz, a vacuum pump, a load cell of 100 kg and a cavity of $580{\times}580{\times}1,360\;mm^3$. A computer program was developed to switch on or off the magnetrons according to drying schedules, those were based on microwave injection time or the average of wood temperatures. To evaluate the new MW/V dryer the roundwood specimens of rigida pine, poplar and birch were dried. Their log diameters and lengths ranged from 125 to 25 em and from 25 to 50 cm, respectively. In spite of the presence of minor drying defects, the MW/V drying is found to be an effective method for drying short roundwoods. Wooden turneries made of red alder and ash logs were also MW/V dried from green to 4%MC without any degradation. The rates of the MW/V drying were examined for three different lengths of poplar logs.

• Korean Journal of Human Ecology
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• v.14 no.1
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• pp.217-221
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• 2005

In this study, the effect of microwave treatment on physico-chemical properties and microbial changes of beef and pork loin was investigated. Beef and pork were heated in microwave with an adjusted electric output at 500 W and operating frequency 2,450 MHz. The beef and pork samples were treated with microwave for 10 s or 20 s at 50% duty cycle. Drip losses and TBA values of beef and pork samples increased due to the microwave treatment. The samples became darker and more yellowish through microwaves, whereas their redness was unchanged. Microbial content of beef and pork samples declined as the treatment time increased. When pork samples were heated in a microwave oven, organisms were reduced by 2 log cycles in 20 s. It was concluded that a 20 second-long microwave treatment can great1y enhance the microbial safety of the pork sample.