• Nuclear Engineering and Technology
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• v.18 no.3
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• pp.218-227
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• 1986

Studies were conducted to determine the extent of oxidation and same of the mechanical property changes of Zircaloy-4 fuel cladding after it was exposed to hot steam environment. The purpose of these tests was to provide some informations on the embrittlement behavior of CANDU type fuel cladding, which could be experienced under the loss-of-coolant accident conditions. The Zircaloy fuel cladding tubes were exposed in a steam environment at the temperature of 90$0^{\circ}C$, 1,00$0^{\circ}C$. The growth of the ZrO$_2$ layer combined with an oxygen rich $\alpha$-phase layer into the Zircaloy tube material was found as a function of time t and temperature of steam exposure, E=1.1√Dt+0.002 where D is a temperature dependent diffusion coefficient. The tensile strength of the specimens exposed for a short period increased but decreased continuously with further exposure. The circumferential elongation was drastically changed with the exposure time while the hoop strength did't decrease greatly. The X-ray measurement of preferred orientation of the Zircaloy tube material indicated that grains in the as received tube were oriented such that the poles of the basal (0001) planes were predominantly radial, while the poles of the basal plane in the tube materials heattreated at 1,00$0^{\circ}C$ were oriented tangentially. It appears that this reoriented texture may contribute to lessening the decrease of the hoop strength of the heat treated Zircaloy tube material.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.180-187
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• 2015

This study was conducted to determine the effects of feeding by-product feed (BF)-based silage on the performance, blood metabolite parameters, and carcass characteristics of Hanwoo steers. The BF-based silage was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% cut ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial additive (on a wet basis), and ensiled for over 5 d. Fifteen steers were allocated to three diets during the growing and fattening periods (3.1 and 9.8 months, respectively): a control diet (concentrate mix and free access to rice straw), a 50% BF-based silage diet (control diet+50% of maximum BF-based silage intake), and a 100% BF-based silage diet (the same amount of concentrate mix and ad libitum BF-based silage). The BF-based silage was fed during the growing and fattening periods, and was replaced with larger particles of rice straw during the finishing period. After 19.6 months of the whole period all the steers were slaughtered. Compared with feeding rice straw, feeding BF-based silage tended (p = 0.10) to increase the average daily gain (27%) and feed efficiency (18%) of the growing steers, caused by increased voluntary feed intake. Feeding BF-based silage had little effect on serum constituents, electrolytes, enzymes, or the blood cell profiles of fattening steers, except for low serum Ca and high blood urea concentrations (p<0.05). Feeding BF-based silage did not affect cold carcass weight, yield traits such as back fat thickness, longissimus muscle area, yield index or yield grade, or quality traits such as meat color, fat color, texture, maturity, marbling score, or quality grade. However, it improved good quality grade (1+ and 1++) appearance rates (60% for the control group vs 100% for the BF-based silage-fed groups). In conclusion, cheap BF-based silage could be successfully used as a good quality roughage source for beef cattle.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.347-354
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• 2016

This study was conducted to investigate the physical and chemical properties of soils in Saemangeum reclaimed lands. The investigated areas were total 5,020 ha which included 220 ha for Agricultural Life site, 2,450 ha for Tourism & Leisure site, 1,130 ha for Industrial & Research site, 820 ha for Bioenergy crop production site, and 400 ha for Rural City site. Soil samples consisting of the upper 20 cm from the surface were collected in every $200m{\times}500m$ of the each site in March and September, 2015. Particle size distribution of soils in the reclaimed land was 83.2% sand, 8.6% silt and 8.2% clay in average. Soil texture was distributed as 40.8% sandy soil, 35.5% loamy sand, and 19.7% sandy loam. Based on the investigation of soil chemical properties conducted in March, 2015, soil pH, electrical conductivity of a saturated soil paste extract (ECe), and exchangeable (Exch.) $K^+$ and $Mg^{2+}$ concentrations were higher than those of the optimum levels for upland soil, whereas soil organic matter content, available (Avail.) phosphate concentration, and Exch. $Ca^{2+}$ concentration were lower than those of the optimum ranges. Depending on the results of the soil chemical properties measured in September, 2015, soil pH, ECe, and Exch. $K^+$ concentration were higher than those of the optimum levels, but soil organic matter, Avail. phosphate, and Exch. $Ca^{2+}$ concentration were lower than the optimum ranges. In addition, distribution of sodic soil ranged between 41.4% and 50.0%, and saline soils were from 16.4 to 31.8%. Soils with pH values above 7.0 increased from 15.3% in March to 35.2% in September. Soils with ECe values over $4.8dS\;m^{-1}$ increased from 45.6% to 50.7%, whereas soils with the values below $2.0dS\;m^{-1}$ decreased from 42.8% to 36.9%.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.1
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• pp.29-35
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• 1999

Soil structure and organic matter have been known to strongly affect water flow and solute transport, yet little information is available concerning soil hydraulic properties related to soil physical and chemical properties in the forest site. The purpose of this study was to quantify the spatial variability and spatial correlation of the measured parameter values from the plots established with the rainfall simulator on Japanese larch(Larix leptolepis) dominated site in Kwangju. Kyunggi-Do. Measurement of soil water flux and retention were made with the inherent soil texture, soil structure, and organic matter. The method was based on the observation that when water was applied at a constant rate to the soil surface on each plot. The method was simple to apply and consists of following steps: (i) Wet the soil from a rainfall simulator with several known discharge rates on a relatively leveled soil surface with and without organic matter. (ii) Once the borders of the ponded zone were steady, saturated hydraulic conductivity( $K_{s}$) and the matric flux function(F) was evaluated from a regression of flux vs. the reciprocal of the ponded area. A conductivity of the form $K_{i+}$$_1$ $_{c}$= $K_{i}$( $_{c}$) [1-d /dz] where flux continuity implies. For this, continuity of matric potential at the interface at all times are as follows: $_1$( $Z_{c}$) = $_2$( $Z_{c}$) = $_{c}$ for steady state intake from water ponded on the soil surface. Results of this investigation showed the importance of understanding spatial variability in wide differences of water retention and saturated hydraulic conductivity with respect to pore geometry and organic matter contents which influenced the water flux throughout the soil profile.l profile.ile.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.77-82
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• 2011

The use of soft magnetic materials have been increasing in the various industrial fields according to the increasing demand for high performance, automatic, miniaturing equipments in the recent our life. In this study, we investigated the effect of factors on the core loss and magnetic properties of electrical steel and soft magnetic composites. Furthermore, we reviewed the major efforts to reduce the core loss and improve the soft magnetic properties in the two main soft magnetic materials. Domain purification which results from reduced density of defects in cleaner electrical steels is combined with large grains to reduce hysteresis loss. The reduced thickness and the high electrical conductivity reduce the eddy current component of loss. Furthermore, the coating applied to the surface of electrical steel and texture control lead to improve high permeability and low core loss. There is an increasing interest in soft magnetic composite materials because of the demand for miniaturization of cores for power electronic applications. The SMC materials have a broad range of potential applications due to the possibility of true 3-D electromagnetic design and higher frequency operation. Grain size, sintering temperature, and the degree of porosity need to be carefully controlled in order to optimize structure-sensitive properties such as maximum permeability and low coercive force. The insulating coating on the powder particles in SMCs eliminates particle-to-particle eddy current paths hence minimizing eddy current losses, but it reduces the permeability and to a small extent the saturation magnetization. The combination of new chemical composition with optimum powder manufacturing processes will be able to result in improving the magnetic properties in soft magnetic composite materials, too.

• Food Science of Animal Resources
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• v.28 no.2
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• pp.171-180
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• 2008

This study was conducted to investigate the meat quality characteristics of pork loin in 3 crossbred groups (30 pigs/group). The crossbreeds were LY female${\times}$D male, Y female${\times}$B male and L female${\times}$B male (L: Landrace, Y: Yorkshire, B: Berkshire, D: Duroc). Pork loins were collected from animals ($110{\times}120kg$ body weight) slaughtered in a commercial slaughter house and stored at $-3^{\circ}C$. Samples were analyzed for general composition, physico-chemical properties, meat and fat color, texture characteristics, sensory evaluation and fatty acid composition at 24 hrs postmortem, and TBARS (Thiobarbituric Acid Reactive Substances) values were determined at various storage times. The LYD pigs showed a higher back fat thickness than the YB and LB pigs. There were no significant differences in intramuscular fat, intermuscular fat, subcutaneous fat and springiness among the 3 crossbreeds. In addition, there were no significant differences in general composition, pH, drip loss, cooking loss and cooked sensory evaluation among the 3 crossbreeds (p>0.05). The shear force value of LB pork was significantly lower than other crossbreeds (p<0.05). Total heme pigment was significantly higher in YB pork compared to LYD and LB pork (p<0.05). The TBARS value of YB pork was significantly lower than that of LYD pork, except after the I day of storage (p>0.05). TBARS values increased significantly during storage for all three crossbreeds. The lightness (CIE L) of YB pork was significantly lower, while the redness (CIE a) was significantly higher in YB pork relative to the other crossbreeds. With regard to textural properties, the hardness and adhesiveness values were significantly lower in YB pork compared to LB pork. In fresh meat, the color of YB pork was significantly higher than the other breeds (p<0.05). The content of myristic acid (C14:0) was significantly lower, while the content of arachidonic acid (C20:4) was significantly higher in LB pork (p<0.05). These results show that the YB breed has the highest quality meat of the three crossbreeds.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.443-447
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• 2015

Fragaria ${\times}$ ananassa (Duch.) cultivars, 'Wongyo 3 115' a nd 'Wongyo 3 116', we re bre d as a n inte rme diate parent l ine using heterosis of $F_1$ hybrids in octoploid strawberry. These two new cultivars were developed as inbred lines ($S_9$ generation) propagated from both seed and runners/stolons. 'Wongyo 3115', an inbred line derived from the 'Benihoppe' cultivar, has a semi-upright plant shape showing a vigorless growth habit, weaker than the original 'Benihoppe' cultivar; it has early flower bud differentiation and produces 10 flowers per cluster when grown from healthy seed. 'Wongyo 3115' has low yields of conical type fruit with pink colored skin; average fruit weight is approximately 11 g. The important characteristic of 'Wongyo 3115' is its excellent fruit firmness, firmer than the original variety. 'Wongyo 3116', an inbred line derived from the 'Doyonoka' cultivar, has an upright plant shape, vigorless growth habit, weaker than that of the original 'Doyonoka' cultivar; it has early flower bud differentiation and produces 8 flowers per cluster when grown from healthy seed. 'Wongyo 3 116' has oblate type fruits with red skin and an ave rage weight of approximately 12 g. The important characteristics of 'Wongyo 3116' are excellent fruit shape and higher yield than other inbred lines, although it produces small fruits compared to the original cultivar. Both cultivars have excellent taste, high sugar/acid ratio, and good texture. In regards to disease and pest resistance, 'Wongyo 3115' and 'Wongyo 3116' have a tendency to be sensitive to powdery mildew, anthracnose and the two-spotted spider mite.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.634-640
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• 1994

This study was investigate to see the effects of preparation methods on the physicochemical and sensory characteristics of cucumber preserved with salt. The preparation methods were brining the cucumbers in 10 % NaCl solution (boiled, method A), 205 NaCl solution (boiled, method B) an d20 % NaCl solution (cool to $25^{\circ}C$ after boiling, method C). The cucumber preserved with boiled solution and high salt concentration showed slow fermentation rate. The rate of salt penetration during brining of cucumber preserved with salt increased. The green value of cucumber preserved with salt by method B was lower than by method A and C. The cutting force of cucumber preserved with walt measured by texture analyzer showed a rapid increasing rate during initial brining periods. As a result of the sensory evaluation for cucumber preserved with salt, there were significant differences in most of characteristics between the samples at 5% level. The cucumber preserved with salt in boiled 10% NaCl solution (method A) showed the highest scores in most of the characteristics.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1439-1447
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• 1998

Antimicrobial activity of chitosan and chitosan oligosaccharides on the microorganism related to Kimchi was investigated. 5 kinds of chitosan, which have different deacetylation degrees and molecular weights were prepared and its effect on the organoleptic characteristics, pH and titrable acidity of Kimchi in the storage time were examined. C-4 and C-5 chitosan (D.A.:$92{\sim}99%$, M.W.: $16,000{\sim}32,000)$ recorded high score in the texture and showed pH 4.9 and titrable acidity 0.35%, compared with control (pH 4.1, titrarable acidity 0.50 %) evaluated to optimal ripening time. The chitosan oligosaccharides containing relatively large amount of $pentamer{\sim}heptamer$ were chosen from C-4 chitosan hydrolyzates. Antimicrobial activity of C-4 and chitosan oligosaccharides against B. subtilis, B. cereus, Pse. fluorescens, E. coli, Lac. plantarum, Leu. mesenteroides, Lac. brevis, Ent. faecalis and 3 kinds of microflora from Kimchi were examined. The clear zone against microorganism were $9{\sim}20mm$ at 3.0% C-4 chitosan and $8{\sim}24mm$ at 5.0% chitosan oligosaccharides, and MIC of chitosan and chitosan oligosaccharides was shown $0.01{\sim}0.05%$ and $0.05{\sim}0.2%$, respectively. The antimicrobial effect of chitosan and chitosan oligosaccharides was also observed in 3 kinds of total microflora from Kimchi and was most strong in the microflora from the ripening stage of Kimchi, suggesting C-4 chitosan and chitosan oligosaccharides could be applicable to extending shelf-life of Kimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1035-1040
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• 2005

This study was conducted to investigate the surface spraying effect of materials on the rheological properties of frozen starch with microwave heating. Microwave helps reduce cooking time by high temperature, but swiftly snatches moisture from foods such as frozen starches (buns and noodles etc) and makes surface of foods harder. Four types of maltodextrin materials have been prepared for different concentration solutions and sprayed on surface doughs of sheet type. Sprayed dough samples were Quickly frozen at $-70^{\circ}C$ and wrapped with polypropylene film. All the treated samples were kept at 0, -20 and $-50^{\circ}C$, and then taken out periodically for measurement of the quality during storage. The quality attributes evaluated after heating with microwave energy include sensory quality retrogradation, texture, surface color and microstructure. The quality of frozen starches deteriorated with long term storage even at low temperatures of -20 and $-50^{\circ}C$, and the spray materials were found to improve the textural and physical properties of frozen starches in the microwave heating. Particularly, maltodextrin with D.E value of $9\~12$ had the most desirable effects of quality improvement.