• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.2087-2095
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• 1999

One of the main causes of unwanted dimensional changes in precision metal mold casting parts is excessive and irregular residual stresses induced by temperature gradients and plastic deformation in the solidifying shell. Residual stresses can also cause stress cracking, and lower the fatigue life and fracture strength of the casting parts. In the present study, aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling units was designed and the casting specimens were produced to quantify the effects of different cooling conditions on the development of residual stresses. The layer removal method was used to measure the biaxial residual stresses in casting specimens produced from the experiments. The experimental results agreed with Tien-Richmond's theoretical model for thermal stress development for the solidifying metal plate.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.2
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• pp.83-89
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• 2005

This study aims to compare a self-reported and expert-observed method on ergonomic risk factors of Work-related Musculoskeletal Disorders (WMSDs). The checklist was developed based on the results of previous studies, and the symptoms of WMSDs were obtained using a self-reported questionnaire from 1,029 shipyard workers. The risk factors were assessed through the self-report by workers and video analysis by ergonomists. The symptom prevalence at the low back (59.2%), shoulders (50.8 %), and knees (49.7%) were relatively higher than those at other body parts. Odds ratios (ORs) by body parts were 2.48 to 2.90 for the risk job, and the ORs were significantly different from those of the low risk job. The risk factor scores by body parts between workers and ergonomist were very high correlation(r=0.82 to 0.92). The rates of self-report from risk job were 54.0% (elbow and arm) to 72.1 % (low back), but sometimes overestimated(105.7 to 122.6%) than those by ergonomists. The checklist, developed in this study, will be an efficient tool for the evaluation of risk jobs using self-report by workers.

• Korean Journal of Poultry Science
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• v.22 no.4
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• pp.223-223
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• 1995

A study was conducted to compare the quality characteristics among commercial broiler, Wangchoo (imported dual purpose breed) and Korean native chicken(KNC). Thigh and breast meat of the broiler(7-wk old), Wangchoo(15-wk old), and Korean native chicken(15-wk old) stored for 24 h at 5t were used to analyze chemical composition, physico-chemical characteristics, textural traits and sensory evaluation test. Crude fat and moisture contents in broiler meat and crude protein content in KNC were significantly(P<.05) higher than those in the other breeds regardless of parts of the body. Total collagen content in broiler meat was significantly higher than those of the other breeds, however, the heat-soluble and the acid-soluble collagen content in Wangchoo were significantly lower than those of the other breeds. Water-holding capacities of KNC in breast meat, and of broiler in leg meat were significantly higher than that of the other breeds, while the results of the water-holding capacity and the cooking loss were reversed. Myofibrillar fragmentation index in broiler meat was significantly higher than that in the other breeds regardless of body parts. Hardness, elasticity and cohesiveness in Wangchoo were significantly higher than those in the other breeds. The prominent fatty acids were oleic, palmitic and linoleic acids and run up to 79.03~83.82 %, regardless of breeds and parts. The sensory evaluation score of tenderness, taste and preference in Wangchoo were lower compared to the broiler and KNC, however, they were not significantly different between broiler and KNC. In conclusion, the quality characteristics of KNC were excellent compared to Wangchoo.

• Korean Journal of Pharmacognosy
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• v.37 no.1 s.144
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• pp.42-47
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• 2006

The contents of quercetin glyciside in Saururus chinensis Baill was higher in the 2nd year, 1st year and 3rd year in leaves, and in the 1st year, 3rd year and 2nd year in stems in that orders. Content of lignans in the rhizome was not significantly different cultivated years. The total phenolics, quercetin glycoside and EDA of plant parts were higher in order of flower, leaf and chopping sample. The total phenolics and EDA of stem were much lower than parts and quercetin glycoside was not detected.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.510-513
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• 2012

Palladium particles were synthesized by conventional chemical reduction method with ionic liquids. The size and shape of palladium particles were significantly affected by the cation parts of ionic liquids. This is mainly attributed to the different stabilities of the ionic liquid structure formed by the physical bond between the cation parts. Among ionic liquids with [$BF_{4}$] as an anion part, the hexyl substituent in the cation parts was more effective to synthesize palladium particles with the smaller size and more uniform shape.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2008.10a
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• pp.106-109
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• 2008

The aim of this study is to develop a model of layering system for future soldier system. Future soldier has been supposed to carry various digital devices embedded into the combat uniform. The combat uniform must be developed to be fit to soldier's body and movement, and can be felt comfortable to soldier. The Uniform must be studied in ergonomic and physiological component because it is different from the present one. It has many devices inside, so there are some unknown barriers to set the devices on to the body. For making the ergonomic aspect of future combat suits clear, the movement of the body was researched. The size of arms(3 parts), torsos(4 parts), and legs(3 parts) of people were measured by movement. Many dots were drawn on the testees' bodies every 3cm. Each time they made compulsory poses, the distances between dots be measured and analyzed. For making the physiological aspect of future combat suits clear, the thermo-map and sweating map of body were made. The 3 maps - movement, thermo and sweating- were overlapped. The devices for future soldier were arranged on the overlapped map considering relations between devices. The final layering system developed on the arrangement of devices.

• Journal of Communications and Networks
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• v.4 no.4
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• pp.336-343
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• 2002

A major challenge for next generation mobile communication is capturing the system architecture’s complexity with all its internal and external dependencies. Seamless integration of heterogeneous environments in all system parts is a key requirement. Moreover, future systems have to consider the different evolution cycles of individual system parts. Among those, services are expected to change the fastest. With respect to these considerations, we propose an overall architecture for next generation mobile communication systems. It covers all system parts from wireless transmission to applications including network and middleware platform. Our approach focuses on adaptability in terms of recon- figurability and programmability to support unanticipated system evolution. Therefore, we consider abstraction layers which consist of adaptable cooperating components grouped by open platforms rather than rigid system layers. In addition to that, we introduce cross-layer cooperation allowing an efficient use of the available resources. Specific scenarios illustrate the feasibility of our approach.

• Korean Journal of Materials Research
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• v.28 no.2
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• pp.124-128
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• 2018

N-type porous silicon (PS) layers and thermally oxidized PS layers have been characterized by various measuring techniques such as photoluminescence (PL), Raman spectroscopy, IR, HRSEM and transmittance measurements. The top surface of PS layer shows a stronger photoluminescence peak than its bottom part, and this is ascribed to the difference in number of fine silicon particles of 2~3 nm in diameter. Observed characteristics of PL spectra are explained in terms of microstructures in the n-type PS layers. Common features for both p-type and n-type PS layers are as follows: the parts which can emit visible photoluminescence are not amorphous, but crystalline, and such parts are composed of nanocrystallites of several nm's whose orientations are slightly different from Si substrate, and such fine silicon particles absorb much hydrogen atoms near the surfaces. Light emission is strongly dependent on such fine silicon particles. Photoluminescence is due to charge carrier confinement in such three dimensional structure (sponge-like structure). Characteristics of visible light emission from n-type PS can be explained in terms of modification of band structure accompanied by bandgap widening and localized levels in bandstructure. It is also shown that hydrogen and oxygen atoms existing on residual silicon parts play an important role on emission stability.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.330-335
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• 2003

Cirsium japonicum is a herbaceous perennial plant grown worldwide, which has been used as a folklore medicine due to its anti-inflammatory properties. A few studies have reported its functional properties, but analytical methods that more confidently and reproductively analyze the flavonoids are required. To establish analytical methods for the detection of flavones in Cirsium japonicum, the potential of HPLC and LC/MS were investigated. For this, the plants were separated into 4 parts; the root, stem, leaves, and flowers. The flavones in each part of the dried materials were analyzed by HPLC. Identification of flavones was performed by LC/MS. The leaves and flowers of Cirsium japonicum gave the optimum peaks, which were not detected by HPLC in the other parts of plants. Using LC/MS, three kinds of flavones were tentatively identified from the leaves, which were thought to be luteolin (5,7,3',4'-tetrahydroxy-flavone), apigenin (4',5,7-trihy-droxyflavone), and hispidulin (4',5,7-trihydroxy-6-methoxyflavone). Two flavones were detected from the flowers, which were been assumed to be apigenin and luteolin.

• Journal of Ginseng Research
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• v.4 no.1
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• pp.55-64
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• 1980

The distribution pattern of mineral nutrients, among various Parts of Korea ginseng (Panax ginseng C.A. Meyer) was investigated to understand ginseng nutrition by simple correlation analysis. Five·year old ginseng plants grown under four different nutritional environments were sampled and separated into leaf, petiole, stem, rhizome, cortex and epidermis of tap foot, central part of tap root, cortex and epidermis of lateral root, central part of lateral root, fine root in the middle of truly, for chemical analysis. Between mineral nutrients in root, N and P showed highly significant positive correlation each other and with Mg and Cu while all other elements (K, Ca, Mg, Fe, Mn, Zn, Cu, B) showed highly significant positive correlation each other. In shoot, number of mineral nutrient pairs haying significant relation was much less than in root. (Negative: P with Ca or B, K with N, Fe, Mn or Cu, Positive: N with Mg, Fe, Mn or Cu, K with Zn, Ca with Mg, Zn, or B, Fe Mn Cu each other, Mn with B.) The number of pairs having significant correlation in whole plant was approximately the same as the number in root but three of them showed significant negative correlation. The distribution pattern similarity of mineral contents among various parts was also discussed in relation to physiological significance in Korea ginseng plant.