• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.125-125
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• 2003

To assist genetic study of the root development in Panax ginseng, which is one of the most important medicinal plant, expressed sequence tags (EST) analysis was carried out. We constructed a cDNA library using the 14-year ginseng root. Partial sequences were obtained from 2,975 clone. The ESTs could be clustered into 1,991 (70.2%) non-redundant groups. Similarity search of the non-redundant ESTs against public non-redundant databases of both protein and DNA indicated that 1,553 groups show similarity to genes of blown function. These ESTs clones were divided into sixteen categories depending upon gene function. The most abundant transcripts were ribonuclease 1 (67) and ribonuclease 2 (65). Our extensive EST analysis of genes expressed in 14-year ginseng root not only contributes to the understanding of the dynamics of genome expression patterns in root organ but also adds data to the reperoire of all genomic genes.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.27-35
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• 2002

In laser materials processing, localized heating, melting and evaporation caused by focused laser radiation forms a vapor on the material surface. The plume is generally an unstable entity, fluctuating according to its own dynamics. The beam is refracted and absorbed as it traverses the plume, thus modifying its power density on the surface of the condensed phases. This modifies material evaporation and optical properties of the plume. A laser-produced plasma plume simulation is completed using axisymmetric, high-temperature gas dynamic model including the laser radiation power absorption, refraction, and reflection. The physical properties and velocity profiles are verified using the published experimental and numerical results. The simulation results provide the effect of plasma plume fluctuations on the laser power density and quantitative beam radius changes on the material surface. It is proved that beam absorption, reflection and defocusing effects through the plume are essential to obtain appropriate mathematical simulation results. It is also found that absorption of the beam in the plume has much less direct effect on the beam power density at the material surface than defocusing does and helium gas is more efficient in reducing the beam refraction and absorption effect compared to argon gas for common laser materials processing.

• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.136-140
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• 2002

Every year fish skin, bone and intestines are discarded as processing waste material. The use of fish processing waste material is more economical and environmental-friendly. The leather-like material was produced using shark intestine. Physical charactistics such as tensile strength, elongation, tongue tearing strength, and bursting strength of the leather-like material were measured, and compared with those of a commercial leather product. The values of tensile strength, elongation, tongue tearing strength, and bursting strength of the leather-like material were $3.3kg/mm^2$, $53\%$, 13.0kg/mm and $18kg/cm^2$, respectively. Elongation $(l09\%)$ of the leather-like material coated with lacquer was higher than that of a commercial leather material, and the other factors were similar. The tensile strength and tongue tearing strength of the leather-like material was higher than those of shoes leather, but bursting strength was lower. These results suggested a potential value to use the leather-like material from shark intestines as a substitute for commercial leathers.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.511-515
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• 2014

The thermodynamic instability of bubbles in wet-foam colloidal suspension is due to the substantial area of their gas/liquid interface. Several physical processes lead to gas diffusion from smaller to larger bubbles, resulting in a coarsening and Ostwald ripening of wet foam. This includes a narrowing of the bubble size distribution. The distribution and microstructure of porous ceramics, the adsorption free energy and Laplace pressure of $Al_2O_3$ particle-stabilized colloidal suspension, and $SiO_2$ content were investigated for tailoring the bubble size. Wet-foam stability of more than 80% is related to the degree of hydrophobicity with contact angles of $62-70^{\circ}$ achieved from the surfactant. The contact angle replaces part of the highly energetic interface and lowers the free energy of the system. This leads to an apparent increase in the surface tension (26-33 mN/m) of the colloidal suspension.

• Plant Biotechnology Reports
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• v.4 no.3
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• pp.223-228
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• 2010

Schizonepeta tenuifolia (Korean name "Hyung- Gae") is an oriental medicinal plant that is widely used in Korea, China and Japan. S. tenuifolia (Hyung-Gae) has many pharmacological activities and is mostly used for many medicinal preparations. The dried aerial part (spikes and stems) of three oriental medicinal plants, S. tenuifolia (Hyung-Gae), Agastache rugosa (Kwhak-Hyang) and Elsholtzia ciliata (Hyang-Yoo) belonging to the same family, mint family Labiaceae, have such similar shape and smell that it is difficult to differentiate between them. The trnL-F regions of chloroplast DNA of the three medicinal plants were sequenced and used as targets in multiplex PCR reaction to identify S. tenuifolia. After alignment of trnL-F sequences of the authenticated plant samples, one single nucleotide polymorphism (SNP) specific to S. tenuifolia was found. Based on this SNP, a new primer was designed that specifically amplifies the trnL-F region of S. tenuifolia. The established multiplex-PCR was proven to be effective in the differentiation of commercial S. tenuifolia samples from A. rugosa and E. ciliata. This rapid and accurate molecular method is highly promising for use in the food industry.

• Journal of Powder Materials
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• v.15 no.3
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• pp.221-226
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• 2008

Silver coated copper composite powders were prepared by electroless plating method by controlling the activation and deposition process variables such as feeding rate of silver ions solution, concentration of reductant and molar ratio of activation solution $(NH_4OH/(NH_4)_2SO_4)$ at room temperature. The characteristics of the product were verified by using a scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic absorption (A.A.). It is noted that completely cleansing the copper oxide layers and protecting the copper particles surface from hydrolysis were important to obtain high quality Ag-Cu composite powders. The optimum conditions of Ag-Cu composite powder synthesis were $NH_4OH/(NH_4)_2SO_4$ molar ratio 4, concentration of reductant 15g/l and feeding rate of silver ions solution 2 ml/min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.4
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• pp.395-399
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• 2007

The purpose of this study was to investigate the antioxidant and fibrinolytic activities of saltwort fermented juice. Saltwort extract was fermented using lactic acid bacteria at $30^{\circ}C$ for 3 days and the fermented juice was analyzed for its functionality as a potential functional food source. The addition of sugar improved the cell viability during fermentation of saltwort. At the concentration of 50%, lyophilized fermented juice showed DPPH-radical scavenging activities of 23.7% and SOD-likely activity of 34.5%. Fibrinolytic activity of fermented juice was also observed at a concentration of 25%. In conclusion, saltwort fermented juice appears to have not only anti-oxidant effect but also cardiovascular protection.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.537-544
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• 2004

An effective methodology is reported for determining the optimal lot size of batch processing and storage networks which include uncertain demand forecasting. We assume that any given storage unit can store one material type which can be purchased from suppliers, internally produced, infernally consumed, transported to or from other sites and/or sold to customers. We further assume that a storage unit is connected to all processing and transportation stages that consume/produce or move the material to which that storage unit is dedicated. Each processing stage transforms a set of feedstock materials or intermediates into a set of products with constant conversion factors. A batch transportation process can transfer one material or multiple materials at once between sites. The objective for optimization is to minimize the probability averaged total cost composed of raw material procurement, processing setup, transportation setup and inventory holding costs as well as the capital costs of processing stages and storage units. A novel production and inventory analysis formulation, the PSW(Periodic Square Wave) model, provides useful expressions for the upper/lower bounds and average level of the storage inventory. The expressions for the Kuhn-Tucker conditions of the optimization problem can be reduced to two sub-problems. The first yields analytical solutions for determining lot sires while the second is a separable concave minimization network flow subproblem whose solution yields the average material flow rates through the networks for the given demand forecast scenario. The result of this study will contribute to the optimal design and operation of the global supply chain.

• Korean Journal of Materials Research
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• v.29 no.1
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• pp.23-29
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• 2019

Three-dimensional(3D) printing is a process for producing complex-shaped 3D objects by repeatedly stacking thin layers according to digital information designed in 3D structures. 3D printing can be classified based on the method and material of additive manufacturing process. Among the various 3D printing methods, digital light processing is an additive manufacturing technique which can fabricate complex 3D structures with high accuracy. Recently, there have been many efforts to use ceramic material for an additive manufacturing process. Generally, ceramic material shows low processability due to its high hardness and strength. The introduction of additive manufacturing techniques into the fabrication of ceramics will improve the low processability and enable the fabrication of complex shapes and parts. In this study, we synthesize silica composite material that can be applied to digital light processing. The rheological and photopolymeric properties of the synthesized silica composite are investigated in detail. 3D objects are also successfully produced using the silica composite and digital light processing.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.114-118
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• 2001