• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.74-84
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• 1998

A doubly resonant ultrasonic transducer has been designed as an attempt to increase the bandwidth of underwater transducers. The dual resonance conditions were accomplished by attaching a single acoustic matching layer on the front face of a Tonpilz transducer consisted of an aluminum head, a piezoelectric ring, a brass tail and a prestress bolt. A modified Mason's model was used for the performance analysis and the design of transducers, and the constructed transducers were tested experimentally and numerically by changing the impedances and thicknesses of the head, tail and matching layers in the water tank. Two distinct resonance peaks in the transmitting voltage response(TVR) of a developed transducer were observed at 34.3 and 40.4 kHz, respectively, with the difference frequency of 6.1kHz and the center frequency of 37.2kHz. The values of TVR at these frequencies were 136.5 dB re $1\;\muPa/V$ at 34.3 kHz and 136.8 dB re $1\;\muPa/V$ at 40.4 kHz, respectively. Reasonable agreement between the experimental results and the numerical results was achieved. From this result, it is expected that the generation of the distinct resonances at any two desired frequencies can be achieved through the proper choice of the matching layer to provide the impedance transformation between the transducer and the medium.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.437-444
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• 2008

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beer patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation, the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed some-what higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.419-426
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• 2010

This study was conducted to investigate the effect of different castration ages on meat quality and sensory properties of Korean native black goats over 410 days. For the experiment, 32 heads of goat (eight heads/4 treatment) were subjected to either a control (5 month non-castration), T1 (7 month castration), T2 (5 month castration) or T3 (3 month castration). The total weight gain for Korean native black goats was highest in the T2 group after feeding for 410 days and the weight gain/day tended to be similar to the total weight gain. The total feeding amounts were lowest (410.82 kg) in T3; however, the feed intake ratio was 16.39 in T2, indicating that it had the best feed efficiency among groups. The cooking loss and drip loss of the Korean native black goats was highest in the control, being 35.53% and 2.08%, respectively (p<0.05), while the total cholesterol of the treatments was higher than that of the control (p<0.05). Moreover, the overall sensory evaluation of the treatment groups was low, indicating that there was more meat flavor when compared to the controls in terms of juiciness, tenderness, flavor, texture, black goat off-flavor and overall evaluation (p<0.05). T2 was found to have the best meat flavor upon sensory evaluation. Additionally, the meat color of the control showed the highest $L^*$ value and Hue value, while T3 showed the highest $a^*$ value (3.61) and T2 showed the highest $b^*$ value and Chroma. The composition of fatty acids was 53.76% oleic acid in T2, while the amounts of Mono-unsaturated fatty acid (MUFA) were highest in T1 and T2 (p<0.05). As a result, the MUFA/SFA ratios of T1 and T2 were higher than those of the control (p<0.05). In conclusion, it is most advantageous to castrate Korean native black goats at the age of 5 months for the best performance and meat quality.

• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Fire Science and Engineering
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• v.31 no.4
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• pp.95-102
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• 2017

The fires in the traditional markets often occur recently with the most of them expanded into great fires so that the damage is very serious. The status of traditional markets handling the distribution for ordinary people is greatly shrunk with the aggressive marketing of the local large companies and the foreign large distribution companies after the overall opening of the local distribution market. Most of the traditional markets have the history and tradition from decades to centuries and have grown steadily with the joys and sorrows of ordinary people and the development of the local economy. The fire developing to the large fire has the characteristics of the problem that the fire possibility is high since all products can be flammable due to the deterioration of facilities, the arbitrary modification of equipment, and the crowding of the goods for sale. Furthermore, most of the stores are petty with their small sizes so that the passage is narrow affecting the passage of pedestrians. Accordingly, the traditional markets are vulnerable to fire due to the initial unplanned structural problem so that the large scale fire damage occurs. The study is concerned with systematically classifying and analyzing the result by applying the TRIZ tool to the fire risk factors to extract the fundamental problem with the fire of the traditional market and make the active response. The study was done for preventing the fire on the basis of it and the expansion to the large fire in case of fire to prepare the specific measure to minimize the fire damage. On the basis of the fire expansion risk factor of the derived traditional market, the study presented the passive measures such as the improvement of the fire resisting capacity, the fire safety island, etc. and the active and institutional measures such as the obligation of the fire breaking news facilities, the application of the extra-high pressure pump system, the divided use of the electric line, etc.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.179-189
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• 2002

The Geology of the Shizhuyuan W-Sn-Bi-Mo deposits, situated 16 Ian southeast of Chengzhou City, Hunan Province, China, consist of Proterozoic metasedimentary rocks, Devonian carbonate rocks, Jurassic granitic rocks, Cretaceous granite porphyry and ultramafic dykes. The Shizhuyuan polymetallic deposits were associated with medium- to coarse-grained biotite granite of stage I. According to occurrences of ore body, ore minerals and assemblages, they might be classified into three stages such as skarn, greisen and hydrothernlal stages. The skarn is mainly calcic skarn, which develops around the Qianlishan granite, and consists of garnet, pyroxene, vesuvianite, wollastonite, amphibolite, fluorite, epidote, calcite, scheelite, wolframite, bismuthinite, molybdenite, cassiterite, native bismuth, unidetified Bi- Te-S system mineral, magnetite, and hematite. The greisen was related to residual fluid of medium- to coarse-grained biotite granite, and is classified into planar and vein types. It is composed of quartz, feldspar, muscovite, chlorite, tourmaline, topaz, apatite, beryl, scheelite, wolframite, bismuthinite, molybdenite, cassiterite, native bismuth, unknown uranium mineral, unknown REE mineral, pyrite, magnetite, and chalcopyrite with minor hematite. The hydrothermal stage was related to Cretaceous porphyry, and consist of quartz, pyrite and chalcopyrite. Scheelite shows a zonal texture, and higher MoO) content as 9.17% in central part. Wolframite is WO); 71.20 to 77.37 wt.%, FeO; 9.37 to 18.40 wt.%, MnO; 8.17 to 15.31 wt.% and CaO; 0.01 to 4.82 wt.%. FeO contents of cassiterite are 0.49 to 4.75 wt.%, and show higher contents (4.]7 to 4.75 wt.%) in skarn stage (Stage I). Te and Se contents of native bismuth range from 0.00 to 1.06 wt.% and from 0.00 to 0.57 wt.%, respectively. Unidentified Bi-Te-S system mineral is Bi; 78.62 to 80.75 wt.%, Te; 12.26 to 14.76 wt.%, Cu; 0.00 to 0.42 wt.%, S; 5.68 to 6.84 wt.%, Se; 0.44 to 0.78 wt.%.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.526-532
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• 2017

Development, survival, and reproduction of brown planthopper (BPH) Nilaparvata lugens $St{\aa}l$ (Hemiptera: Delphacidae), were studied in laboratory at $25{\pm}2^{\circ}C$, $65{\pm}5%$ RH and a 16L : 8D hours photoperiodism on five rice cultivars of: Dongjin 1ho, Chungchungbyeo, Jangseongbyeo, Chinnongbyeo and Jungmo 1045. BPH nymphs successfully survived on all rice cultivars, although survival rate was lowest on Jangseongbyeo (36.0%). Developmental time of immature stages ranged from $11.7{\pm}0.59d$ on Jungmo 1045 to $12.8{\pm}0.59d$ on Chinnongbyeo. Reproductive period and female longevity were longest on Dongjin 1ho, Chinnongbyeo and Jungmo 1045 while highest fecundity of N. lugens being observed on these three rice cultivars. Highest and lowest net reproductive rates were calculated on rice cultivars, Jungmo 1045 and Jangseongbyeo, respectively. Mean generation time was the longest on rice cultivar Dongjin 1ho. Respective descending order of intrinsic rates of population increase were on Jungmo 1045, Chinnongbyeo, Dongjin 1ho, Chungchungbyeo and Jangseongbyeo. These population parameters showed that N. lugens can successfully survive and reproduce on Chinnongbyeo and Jungmo 1045.

• Journal of Nutrition and Health
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• v.17 no.2
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• pp.126-136
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• 1984

The long-term effects of vegetable and animal high fat diet on the lipid metabolism were investigated in male weaning rats. The rats were fed one of four semipurified diet ad libitum : control diet supplied 12% of calories as fat(control group), low fat diet supplied 3% of calories as fat (3% F group), 45% corn oil diet supplied 45% calories from corn oil (45% C group) and 45% butte. fat diet supplied 45% calories from butter fat (45 % B group). Incorporation of $acetate-1-^{14}C$ into lipid of liver, serum and adipose tissue as well as exhalation of $^{14}CO_{2}$ from $acetate-1-^{14}C$ were observed in rats fed for 4,8 and 12 weeks. The weigh of epididymal adipose tissue of rats, fed 45% corn oil and 45% butter fat . from 4 weeks to 8 weeks were higher, but not different at 12 weeks, compared with those of control group. The weight of abdominal adipose tissue appeared to be similar to those of epididymal adipose tissue. Incorporations of $acetate-1-^{14}C$ into lipid of liver were remarkably decreased in high fat diet groups, especially in 45% C group, but in 3% F group were increased more than those of control group. Incorporations of $acetate-1-^{14}C$ into epididymal adipose tissue in 3% F, 45% C and 45% B group at 8 weeks were remarkably increased but not different at 12 weeks, compared with those of control group. The incorporation of {acetate-1-}^{14}C into abdominal adipose tissue appeared to be similar to those of epididymal adipose tissue. Incorporations of $acetate-1-^{14}C$ into lipid of serum in 45% C and 45% B group were reduced reasonably at 4 and 8 weeks of diet as compared with those of control group. Exhalation of $^{14}CO_{2}$ was increased to maximum level at 10 minutes after injection of $acetate-1-^{14}C$. Expiration of $^{14}CO_{2}$ in 45% C and 45% B group were higher than those in 3% F and control group for initial 5 minutes after injection, but expirations of $^{14}CO_{2}$ did not have significant difference among groups of diet since 10 minutes.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.2
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• pp.67-74
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• 2010

Law-protected trees are our precious asset as natural resources with history and tradition and natural heritage which should be protected and maintained well to bequeath next generation. Law-protected trees have not only thremmatologic and genetic meaning but also environmental and emotional meaning for their value to be high. This study investigated location, vitality, wrapping condition of root area and status of maintenance of the trees to figure out their growth environment and status of maintenance in a small-middle city through survey on those of law-protected trees in Je-cheon. There showed 300 more year old trees in Je-cheon mostly and the number of trees located in flat fields was the highest. For location type, village, hill and road types were presented in the order and for degree of development, land for building was found most frequently. The average electric resistance of the formative layer was measured to be $8.4k{\Omega}$ and four trees showed bark separation. Most law-protected trees underwent tree surgery, and complete bareness of root area was observed in a tree. The root area of two trees was covered with concrete. pH of soil was recorded to be 5.0~8.4 with its average of 7.1 and electric conductivity(EC) was less than 0.5 dS/m. For status of maintenance rearing facilities were placed for 16 trees out of totally 48 ones and stone fence was done for three ones. Tree surgery was conducted for 33 trees to prevent and to treat decomposed parts of holes. Direction boards were installed for 23 trees. Based on these results, measures to manage systematically law-protected trees in Jecheon could be suggested as follows. First, a sufficient space for growth of low part of trees should be secured. Second, a voluntary management should be induced by advertising them to residents in a community. Third, rearing facilities and direction boards of law-protected trees should be placed and related education should be conducted. Fourth, through operation of the department for law-protected trees consisting of related professions and cooperation among related departments the trees should be maintained continuously.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.969-977
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• 2001

The purpose of this study was to investigate disinfection state and effective factors of utensils and equipments used to foodservice of elementary schools in Busan area, The questionnaire which was administered to 160 dietitians was used in this study as a survey method. The results were as follows. The disinfection method of tray was mainly used by electric gas. Table and other products of stainless steel sanitized by sodium hypochlorite and hot water, but above 51% of slicer. grinder and peeler were not sanitized after used. The products of wood and plastic also used mainly sodium hypochlorite and hot water as sanitizers. In disinfection time, knife, wood spoon and plastic products should be sanitized on demand, but 30.9~53.5% of this utensils except rice scoop were sanitized on demand that showed deficiency of cognition for sanitation. The disinfection of most of utensils and equipments was conducted every day, but food case, slicer, peeler, grinder and wood spoon showed lower disinfection frequency than other products, The method of disinfection was related to dietitians age and career number of total serving, duration of foodservice and serving place, The disinfection time was also affected by dietitians age and educational level, and serving place. The disinfection frequency was affected by number of employee, number of total serving and duration of foodservice. Therefore based on the results of this study, it should be given to the microbiological study on disinfection method of utensils such as slicer, grinder, peeler, large spoon, plastic prouducts and the dietitians sanitation training also should be conducted continuously.