• Food Science and Preservation
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• v.9 no.1
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• pp.19-27
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• 2002

The effect of gamma irradiation was investigated on the microbiological and physicochemical qualities of boiled-dried anchovies (large- and smallsized) packed in PVC film (0.06 ㎜) during storage at 15$\pm$1$\^{C}$ for 6 months. On the other hand, thermoluminescence characteristics of minerals extracted from the sample were analyzed to evaluate its possibility in detecting the irradiated anchovies. The samples were contaminated by microbial levels of 104∼106 CFU/g in total aerobic bacterial counts and negative in coliforms, which were different depending on the sample sizes. Gamma irradiation at 3 kGy was effective for improving the hygienic quality of both samples for 6 months, keeping the microbial population less than 20 CFU/g. Besides it was not detrimental to the quality attributes, such as instrumental color parameters L, a, b, ΔE), browning, TBA value, volatile basic nitrogen, trimethylamine-N and sensory properties(appearance, color, odor, tape, overall acceptability). However, storage conditions (time, temperature, packing) showed a critical factor nfluencing the quality changes of dried anchovies. Thermoluminscence analysis was prove to distinguish irradiated from non-irradiated anchovies by comparing both temperature at which glow curves appear and the curve intensity, that was possible even after 6 months at - 20$\^{C}$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.3
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• pp.329-338
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• 2019

Suction of unsaturated bentonite buffers is a very important input parameter for hydro-mechanical performance assessment and design of an engineered barrier system. This study analyzed suction measurement techniques and constitutive models of unsaturated porous media reported in the literature, and suggested suction measurement techniques and constitutive models suitable for bentonite buffer in an HLW repository. The literature review showed the suction of bentonite buffer to be much higher than that of soil, as measured by total suction including matric suction and osmotic suction. The measurement methods (RH-Cell, RH-Cell/Sensor) using a relative humidity sensor were suitable for suction measurement of the bentonite buffer; the RH-Cell /Sensor method was more preferred in consideration of the temperature change due to radioactive decay heat and measurement time. Various water retention models of bentonite buffers have been proposed through experiments, but the van Genuchten model is mainly used as a constitutive model of hydro-mechanical performance assessment of unsaturated buffers. The water characteristic curve of bentonite buffers showed different tendencies according to bentonite type, dry density, temperature, salinity, sample state and hysteresis. Selection of water retention models and determination of model input parameters should consider the effects of these controlling factors so as to improve overall reliability.

• Parasites, Hosts and Diseases
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• v.57 no.1
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• pp.9-15
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• 2019

Melting temperature shift ($T_m-shift$) is a new detection method that analyze the melting curve on real-time PCR thermocycler using SYBR Green I fluorescent dye. To establish a $T_m-shift$ method for the detection of Ancylostoma ceylanicum and A. tubaeforme in cats, specific primers, with GC tail of unequal length attached to their 5' end, were designed based on 2 SNP loci (ITS101 and ITS296) of the internal transcribed spacer 1 (ITS1) sequences. The standard curve of $T_m-shift$ was established using the standard plasmids of A. ceylanicum (AceP) and A. tubaeforme (AtuP). The $T_m-shift$ method stability, sensitivity, and accuracy were tested with reference to the standard curve, and clinical fecal samples were also examined. The results demonstrated that the 2 sets of primers based on the 2 SNPs could accurately distinguish between A. ceylanicum and A. tubaeforme. The coefficient of variation (CV) of $T_m$- values of AceP and AtuP was 0.07% and 0.06% in ITS101 and was 0.06% and 0.08% in ITS296, respectively. The minimum detectable DNA concentration was $5.22{\times}10^{-6}$ and $5.28{\times}10^{-6}ng/{\mu}l$ samples of AceP and AtuP, respectively. The accuracy of $T_m-shift$ method reached 100% based on examination of 10 hookworm DNA samples with known species. In the clinical detection of hookworm in 69 stray cat fecal sample, the $T_m-shift$ detection results were consistent with the microscopic examination and successfully differentiated between the 2-hookworm species. In conclusion, the developed method is a rapid, sensitive and accurate technique and can provide a promising tool for clinical detection and epidemiological investigation of cat-derived hookworms.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.668-681
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• 2020

The purpose of this study was aimed to isolate a Salmonella Typhimurium-specific phage (KFS-ST) from washing water in a poultry processing facility and to investigate the feasibility of the KFS-ST as a novel bio-receptor for the magnetoelastic (ME) biosensor method. KFS-ST against S. Typhimurium was isolated, propagated, and purified using a CsCl-gradient ultracentrifugation. Morphological characteristics of KFS-ST were analyzed using transmission electron microscopy (TEM). Its specificity and efficiency of plating analysis were conducted against 39 foodborne pathogens. The temperature and pH stabilities of KFS-ST were investigated by the exposure of the phage to various temperatures (-70℃-70℃) and pHs (1-12) for 1 h. A one-step growth curve analysis was performed to determine the eclipse time, latent time and burst size of phage. The storage stability of KFS-ST was studied by exposing KFS-ST to various storage temperatures (-70℃, -20℃, 4℃, and 22℃) for 12 weeks. KFS-ST was isolated and purified with a high concentration of (11.47 ± 0.25) Log PFU/mL. It had an icosahedral head (56.91 ± 2.90 nm) and a non-contractile tail (225.49 ± 2.67 nm), which was classified into the family of Siphoviridae in the order of Caudovirales. KFS-ST exhibited an excellent specificity against only S. Typhimurium and S. Enteritidis, which are considered two of the most problematic Salmonella strains in the meat and poultry. However, KFS-ST did not exhibit any specificity against six other Salmonella and 27 non-Salmonella strains. KFS-ST was stable at temperature of 4℃ to 50℃ and at pH of 4 to 12. The eclipse time, latent time, and burst size of KFS-ST were determined to be 10 min, 25 min and 26 PFU/ infected cell, respectively. KFS-ST was relatively stable during the 12-week storage period at all tested temperatures. Therefore, this study demonstrated the feasibility of KFS-ST as a novel bio-receptor for the detection of S. Typhimurium and S. Enteritidis in meat and poultry products using the ME biosensor method.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.597-605
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• 2015

The method of concrete mix design used in this study aims to achieve the identical specified design strength, applying different types and replacement ratio of mineral admixtures and afterwards, fire tests were conducted using the standard time-temperature curve specified in the ASTM E119 to identify the influences of the types of mineral admixtures on the fire resistance performance of high strength concrete(HSC). The least spalling was observed in the test specimen containing blast furnace slag as a partial replacement of cement, while the most significant spalling phenomena were observed in the blast furnace slag test specimen that silica-fume was added in. In particular, the reasonable volume of spalling was observed when solely replaced by silica fume. However, the influence of the cement replacement by silica fume and blast furnace slag on the increases of spalling can be explained through blocked pores by the fine particles of silica fume, leading to decreases in permeability.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.194-200
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• 2010

Recently, a longitudinal tunnel construction has increased because of subway construction extension, geomorphological effect and the development of construction Technologies etc. When the fire occurs in a tunnel and an underground structure, the many damage of human life and the economic losses are caused. In Korea, fire resistance character study of a tunnel and an underground structure is proceeding. However, when a concrete is exposed to high temperature, study of load carrying capacity reduction and stability evaluation for spalling of a concrete is not enough. Therefore in this study, fire resistance character of a concrete evaluated according to time heating temperature curve(RABT and RWS) and a result compared on virtual fire accident in order to apply fire scenario. Also this study performed thermo-mechanical coupled analysis of a FEM-based numerical technique and estimated fire-induced damage of a tunnel and an underground structure.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.327-334
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• 2015

We investigated the current and potential spatial distributions and habitable areas of Biston robustum and Camellia japonica in South Korea in order to provide useful data for the conservation of C. japonica and minimize the damage caused by B. robustum. It was predicted that, by 2070, although B. robustum would be widely distributed throughout the Korean Peninsula, except for the western and eastern coastal areas, it would be narrowly distributed along the Sokcho-si and Goseong-gun coastlines in Gangwon Province. C. japonica is currently located along the southern coastline but its critical habitable area is predicted to gradually disappear by 2070. Assessment of the potential distribution probabilities of B. robustum and C. japonica revealed that the area under the curve (AUC) values were 0.995 and 0.991, respectively, which indicate high precision and applicability of the model. Major factors influencing the potential distribution of B. robustum included precipitation of wettest quarter and annual precipitation (BIO16 and BIO12), whereas annual mean temperature and mean temperature of wettest quarter (BIO1 and BIO8) were important variables for explaining C. japonica distribution. Overlapping areas of B. robustum and C. japonica were $11,782km^2$, $5447km^2$, and $870km^2$ for the current, 2050-predicted, and 2070-predicted conditions, respectively, clearly showing a dramatic decrease in area. Although it is predicted that B. robustum would cause continuous damage to C. japonica in the southern part of the Korean Peninsula, such impacts might diminish over time and become negligible in the future.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.3
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• pp.252-257
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• 2000

To investigate the thermal preheating effect of the GaAs substrate exerted on the ZnS epilayers for the first time, ZnS epilayers were grown on the GaAs (100) substrate by hot wall epitaxy. The thermal preheating temperature was $450^{\circ}C$~$660^{\circ}C$. The full width at half maximum values of double crystal rocking curve were the smallest for the ZnS epilayers grown on the GaAs thermally preheated at around both $500^{\circ}C$ and $600^{\circ}C$. However, photoluminescence characteristics of ZnS epilayers were better at $600^{\circ}C$ than at $500^{\circ}C$. Therefore, it was shown that the optimum preheating temperature of the GaAs substrate for the growth of high quality ZnS epilayer was around $600^{\circ}C$. From these experimental results, it was shown that the crystal quality and the PL properties of ZnS epilayers were enhanced for the GaAs substrates thermally preheated at $600^{\circ}C$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2183-2190
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• 2000

A thermal aging is observed in a primary reactor cooling system(RCS) made of a casting stainless steel when the RCS is exposed for long period at the reactor operating temperature, 290~3300C An investigation of effects of thermal aging on a low cycle fatigue characteristics included a stress variations caused by a reactor operation and trip, is required. The purpose of the present investigation is to find an effect of a thermal aging of the CF8M on a low cycle fatigue life. The specimen of CF8M are prepared by an artificially accelerated aging technique holding 300 and 1800hr at 4300C respectively. The low cycle fatigue tests for the virgin and two aged specimens are performed at the room temperature for various strain amplitudes($\varepsilon$ta), 0.3, 0.5, 0.8, 1.0, 1.2 and 1.5% strain. Through the experiment, it is found that the fatigue life is rapidly reduced with an creasing of the aging time. The experimental fatigue life estimation formulas between the virgin and two aged specimen are obtained and are proposed to a analysis purpose.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.4
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• pp.179-186
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• 1974

The followings are some results obtained from a series of experiments for the culture of eels from the elver stage in the laboratory from April 1973 to June 1974. 1. The optimum temperature turned out as 30t in the early stage culture. 2. The exponential curve of growth rate for a ten day period at the temperature between $20^{\circ}C$ and $30^{\circ}C$ was represented by the following equation: $$R=0.0056296\;T^{1.80740}$$ 3. The elvers and small eels that were kept improperly for a long time before this experiment also showed the same growth rate, compared with other healthful eels captured directly from the estuarine areas. 4. Those that showed retarded growth among a group of eels during the culture recovered the normal growth rate if graded out and kept in the other aquarium. 5. Feeding rate was not affected when the content of ammonia was less than 5 ppm, but it decreased by half when the content exceeds 6 ppm. 6, The elimination of fecal stuffs and uneaten dispersed feed was very important for the maintaining the water in quality.