• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.796-803
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• 1996

Gamma irradiation was applied to soybean(Glycine max.), Hwangkeum, at dose levels of 0, 5, 10 and 20 kGy to improve the physical properties of soybeans. The time to reach a fixed moisture content was reduced depending on the increment of soaking temperatures and applied irradiation dose levels. Irradiation at 5~20 kGy resulted in reduction in soaking time of the soybeans by about 3~6 hrs at soaking temperature of $20^{\circ}C.$ The degree of cooking of soybeans in boiling water was determined by measuring the maximum cutting force of cotyledon. The cutting force to reach complete cooking was about 145g/g. Irradiation at 5~20 kGy resulted in a reduction of cooking time of soybeans by 55~75% as compared to the nonirradiated soybean. In electron microscopic observation of seed coat inner, the parenchyma of nonirradiated soybean showed tight fibrillar structure, whereas that of irradiated soybeans showed loosened and deformed structure. The microstructure of compressed cells and cotyledon epidermis was also deformed by gamma irradiation. In subcellular structure of cotyledon, the roundness of protein body was deformed and changed to spike shape at 20 kGy. Also, the size of lipid body decreased as the irradiation dose levels increased.

• Food Science and Preservation
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• v.18 no.4
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• pp.502-507
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• 2011

To investigate the optimal salting conditions, the physicochemical properties of Dolsan leaf mustard were compared under various salting times and using various washing methods and storage temperatures at 10% saline. On the other hand, the cell number of lactic-acid bacteria in Dolsan leaf mustard salted under the optimal conditions was also examined during the 50-day storage. The results of the sensory evaluation of the crispness value of the Dolsan leaf mustard treated with stepwise washing after 8h salting showed the optimal conditions for long-term preservation. The pH of the salted Dolsan leaf mustard decreased with the increase in the lactic-acid bacteria during the storage at $4^{\circ}C$. The cutting energy slowly increased during the storage, but the cutting energy of the salted Dolsan leaf mustard treated with stepwise washing remained at the initial values. The color of the salted Dolsan leaf mustard did not change during 40-day storage, but the mustard turned brown after 50-day storage, for which reason it could not be made into Dolsan leaf mustard kimchi. These results could be recommended as the optimal salting conditions and storage time of salted Dolsan leaf mustard for making kimchi.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.834-841
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• 2005

Polyethylene glycol esters (PEG-esters) were synthesized by condensation reaction of dicarboxylic acid such as adipic acid and sebacic acid and several PEGs. The PEG-esters were analyzed by FT-IR, $^1H-NMR$ and HPLC for structure analysis, and by GPC for molecular weight. Through the analysis of surface tension, critical micelle concentration (CMC), aluminum contact angle of water solution containing the PEG-ester, the synthetic PEG-esters are proven to exhibit surfactant properties. The surface tension ranged from 45 to 50 dyn/cm depended on the concentration and structures of the PEG-esters. The surface tension of PEG-esters with sebacic acid moiety and short polyoxyethylene unit resulted in lower value than that of PEG-ester with adipic acid moiety and long polyoxyethylene unit. The CMC of water solution containing 2.5 wt% PEG-ester with sebacic acid moiety estimated at $0.9{\times}10^{-5}{\sim}5.3{\times}10^{-3}mol/L$ depended on the structures of PEG-esters. The CMC of PEG-esters with long polyoxyethlene unit showed a higher value than that of PEG-esters with short polyoxyethylene unit. Meanwhile, the CMC of PEG-esters with adipic acid moiety was not distinct due to their high hydrophilic character. As the results of contact angle and cutting time aginst aluminum, the contact angle ranged from $45^{\circ}$ to $53^{\circ}$ depended on the concentration of PEG-esters. The cutting time of aluminum showed the shortest value at CMC, but the longest value above CMC. This fact indicates that the CMC of PEG-esters is a very important factor in drilling aluminum.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.145-153
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• 1995

Effects of lime application levels(0, 10, 50, 100, and 300kg/10a) on three alfalfa cultivars(Dekalb brand 120, Pike, Pioneer brand 5929) were analyaed with respect to the growth, dry matter yield, and inorganic composition of the plants at three cutting periods. Major chemical properties of the soils were also analyzed. Response of the plant height to the lime application level was variable among the cultivars, showing the order of 50>100>300>10>0kg/10a in Dekalb brand 120, 50>100>10>300>0kg/10a in Pike, and 10>50>300>0>100kg/10a in Pioneer brand 5929. The order of dry matter yield response to the lime application level was 50>300>100>10>0kg/10a in Dekalb brand 120, 50>10>300>100>0kg/10a in Pike, and 50>100>10>0>300kg/10a in Pioneer brand 5929. Total dry matter yields at 50kg/10a lime application level were higher than those at any other levels in all the cultivars. Neither a specific pattern nor a significant change in inorganic composition of the plant was found for the lime application levels and cutting times, Soil chemical properties and composition remained with little change after the experiment except the soil pH, which was increased with the lime application level.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 2000.06a
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• pp.195-214
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• 2000

The high-speed steel (shorten as HSS) consists of Fe and several kinds of transition metal carbides. The cutting tools or wear-resistant materials made from HSS experience relatively high thermal shock because a coolant such as water or oil is flowed over the surface of heated HSS. The purpose of this research is to increase the hardness, strength, fracture toughness and thermal shock resistance of HSS. A possible strategy is to incorporate a hard ceramic material with high strength in HSS matrix. This paper describes the processing, microstructure and mechanical properties of the oriented unidirectional mullite fiber/HSS composite. The unidirectional mullite fibers of 10${\mu}{\textrm}{m}$ diameter were dispersed by the ultrasonic irradiation of 38 kHz in an ethylenglycol suspension containing HSS powder of 11${\mu}{\textrm}{m}$ median size. The dried green composites with 4-68 vol% fibers were hot-pressed for 2h at 100$0^{\circ}C$ in Ar atmosphere under a pressure of 39 MPa. The higher density was achieved in the composite with a lower content of fibers. The oriented unidirectional fibers were well dispersed in the HSS matrix. The average distance between the center of fibers in the cross section was close to the value calculated from the fiber fraction. No reaction occurred at the interfaces between HSS and mullite fibers in the composites. The composite with 13.6 vol% fibers showed 100 MPa of four point flexural strength at room temperature. The thermal expansion of composite with heating was influenced by the orientation of mullite fibers.

• Composites Research
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• v.31 no.2
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• pp.69-75
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• 2018

In this study, a grid panel structure in which the woven CFRP composites were stacked in the orthogonal array was proposed and the mechanical properties were analyzed and studied. The grid parts were fabricated by cutting prepregs and laminating them. The grid panel structure was fabricated by co-curing with lower laminate plate in auto-clave process. The behavior of the proposed grid panel structure was evaluated by tests under tensile, compressive, shear, and bending loads. The effect of increasing the stiffness of the orthogonal grid structure was verified through these tests. In addition, the finite element model was constructed and compared with the test results, confirming the validity and reliability of the test and analysis.

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.507-516
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• 2015

This study investigated the quality characteristics and antioxidant activities of wet noodles as well as their cooking properties following the addition of peanut sprout extract (PSE) and powder (PSP), which are known to contain a significant level of resveratrol. Wet noodles were prepared with 0, 2.5, 5, 7.5 and 10% PSE and PSP. Quality characteristics such as increasing volume of noodle, water ratio, turbidity of cooking water and color, texture, and sensory evaluation were then assessed. Additionally, the total resveratrol content in the cooked noodles was analyzed by HPLC and DPPH free radical scavenging capacity. As the amount of PSE and PSP increased, the L value of wet and cooked noodles significantly decreased, whereas the a and b values increased (p<0.001). The L value of cooked noodles was significantly lower compared to wet noodles (p<0.001) whereas the a and b values were higher. For the cutting intensity properties of the cooked noodles, hardness was reduced with increasing amounts of PSE (p<0.001), and was significantly increased in proportion to the amount of PSP (p<0.05). Meanwhile, springiness was not significantly different in all groups. Total resveratrol content and free radical scavenging activity significantly increased in proportion to the amounts of PSE and PSP (p<0.001), especially in noodles containing 5%, 7.5% and 10% PSE and PSP. Finally, sensory evaluation of PSE noodle revealed that color, flavour, taste were significantly decreased (p<0.05). But there was no difference in overall acceptance among cooked noodles with 2.5% to 5% PSE comparison to the control. Sensory characteristics in the PSP noodle showed similar results. In conclusion, these findings suggest that peanut sprout extract and powder could be potentially used as functional food ingredients. In addition, up to 5% PSE and PSP can be substituted for wheat flour.

• Food Science of Animal Resources
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• v.37 no.2
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• pp.162-167
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• 2017

Functional and nutritional soluble proteins can be recovered from surimi (and surimi-like material) processing wastewater, reducing environmental problems and the cost of an irresponsible waste disposal. Recovered proteins may be added back at a low percentage to surimi products. The aim of this work was to evaluate the effect of the addition of soluble recovered proteins (RP), obtained from mechanically separated chicken meat surimi-like material (MSCM-SLM) processing wastewater by acidic pH-shifting, on the composition and texture of RP-MSCM-SLM, with RP contents of 0, 10, 20 and 30% (w/w) in the mixture. For that, proximate composition and gel properties were evaluated. The fat content of the MSCM-SLM was significantly reduced to 11.98% and protein increased to 83.64% (dry basis) after three washing cycles. The addition of 30% RP in the MSCM-SLM significantly augmented the protein content to 93.45% and reduced fat content from to 2.78%. On the other hand, the addition of RP was responsible for a drastic decrease in texture parameters, reaching 252.36 g, 185.23 g.cm, and 6.97 N for breaking force, gel strength and cutting strength, respectively, when 30% of RP was included in the MSCM-SLM. It was concluded that the obtained intermediary product (RP-MSCM-SLM) is a good option to applications in processed meat products where high texture parameters are dispensable, e.g., emulsified inlaid frankfurter-type sausages, but high protein content and low fat content desired.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.4
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• pp.440-450
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• 2003

Statement of problem : The joints of removable partial denture alloys have failed frequently after routine usage. Purpose : The purpose of this study was to evaluate the mechanical properties of the laser welded Co-Cr alloys. Material and method : For this study 20 Co-Cr specimens were casted and 10 of them were seperated on the middle area and laser welded with Alpha laser welding machine(Siro Lasertec, Pforzheim, Germany). Rest of them which were as cast, were used as a control group. For the section of the experimental specimens, wire cutting machine was used to make a even gap of the all specimens. Laser welding was done with manufacturer's instrunction and tested each specimen by Instron Machine. Tensile strength, 0.2% yield strength and % elongations were recorded. Fractured surfaces were investigated with SEM. Results : The results were as follows : 1. The tensile strength of the laser welded group(617.7MPa) was about 75% of the as cast group(820.4MPa). It had stastically significant differences(p<0.05). 2. The % elongation of the experimental group was 6.6 which was lower than the control group(14.3). 3. Fracture of the experimental group occured in the welded surface and showed many voids. In contrast, the fracture surface of the control group was showed rough surfaces without any voids. Conclusion : The tensile strengths of the as-cast joints were higher than those for the laser welded joints, and the % elongation of the experimental group was lower than the control group. Porosity was found in laser-welded joints.

• Journal of the Korean Vacuum Society
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• v.16 no.1
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• pp.74-78
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• 2007

Much interests has been drawn for noble micro-engineering processes for the continuous size reduction on bulk materials from the field of micro-electronics with much downsized IC chips. A traditional microprocessing based on mechanical blade as well as a relatively long pulsed laser usually influence the physico-chemical properties of intact materials when the techniques are applied to process materials with a spatial resolution less than 10 microns. Meanwhile, ultrafast laser pulses are known to exhibit a very small heat-affect zone(HAE) compared to the traditional laser processing and to be applicable for the new functional materials with high performance in optical and electrical properties. In this report, we will review in brief the recent research works on the enhancement of micro-cutting speed of thin silicon wafer as well as the formation of Ge nanostructures based on ultrafast laser pulses.