• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.9
• /
• pp.1273-1278
• /
• 2016

In this study, we optimized conditions for extraction of eleutherosides B and E from stem powder of Acanthopanax. To enhance eleutheroside B and E yields, Acanthopanax sessiliflorus Seeman and Eleutherococcus senticosus Maxim were pre-incubated with the following enzymes: Celluclast, Viscozyme L, Lactozyme, Lecitase, and Novozyme 33095. Treatment with Novozyme 33095, a commercial pectinase, for 3 h resulted in the highest yields of eleutherosides B and E from A. sessiliflorus and E. senticosus. Compared with extraction at $121^{\circ}C$ for 120 min, at $121^{\circ}C$ for 15 min after Novozyme 33095 pre-incubation increased eleutheroside B and E yields from A. sessiliflorus by 7% and 17%, respectively. In the case of E. senticosus, eleutheroside B and E yields increased by 25% and 29%, respectively.

• Journal of the Korean GEO-environmental Society
• /
• v.2 no.3
• /
• pp.81-88
• /
• 2001

The behavior of porous medium is modeled by linear thermoporoelastic behavior, linear poroviscoelastic behavior, poroplastic behavior, and poroviscoplastic behavior, etc. The behavior has, in general, a complicated aspect which makes a mechanical description of the problem with time. Constitutive modeling for deformation behavior of porous medium with coupling effects is needed since there is interaction between the constituents in pores with a relative velocity to each other. In this work, it is explained 3-dimensional behavior depending on degree of saturation for porous medium composed of homogeneous, isotropic materials. It is obtained the governing equations based on continuum porous mechanics. In addition, it is developed constitutive model which can be understood of behavior for porous medium which can be understood, analysed behavior of porous medium. It can be accomplished exact analysis and prediction of behavior in porous medium. The behavior for porous medium is analysed exactly, and the prediction of deformation behavior is accomplished. Consequently, it will be basis to analyze 3-dimensional behavior in municipal solid waste landfill, and the practical using of porous medium ground which are composed of nonhomogeneous, anisotropic materials can be done widely.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.4
• /
• pp.511-519
• /
• 2013

Switching controllers for active magnetic bearings are claimed to minimize the copper losses because they do not use bias currents. In this study, we compare the performances of the switching controller with those of the widely used proportional-derivative (PD) controller. The PD controller is combined with a synchronous notch filter to reduce the effect of the unbalance disturbance. For a fair and objective comparison, the PD controller is designed systematically. The switching controller is designed so that the dynamics of the two controllers are almost identical. A system model is developed. This model includes the flexible modes of the rotor and the dynamics of the sensors and amplifiers. The simulation results show that the switching controller indeed reduces the copper loss at lower speeds. However, it fails to operate around the speed close to the bending mode of the rotor.

• Journal of fish pathology
• /
• v.3 no.2
• /
• pp.81-91
• /
• 1990

Nutritional ceroidosis accompanied with histopathological changes such as myopathy and visceral ceroidosis, was experimentally induced by feeding the oxidized feed with the peroxide value of 98meq/kg, to common carp resulting in some motalities of carp. To see the effect of treacetment survivors of the above fish were orally administered by feeding diets containing daily doses of 3mg and 6mg of glutathione per kg fish for 10 days or 20 days. While control and 3mg dosage group retained viscerral ceroidosis and showed evidence myopathy histo pathologically, the fish treated with 6mg of glutathione for 20days showed obvious reduction of macrophages of ceroid in the viscera.

• Fire Science and Engineering
• /
• v.29 no.4
• /
• pp.67-72
• /
• 2015

A series of fire tests was conducted to examine the fire characteristics of flaming and smoldering combustion of engineered wood products, which have been widely used for furniture and finishing materials in buildings. The engineered wood products of MDF, plywood, and chipboard were ignited by a radiant cone heater with incident heat flux of $50kW/m^2$. During the fire test, key parameters representing the fire characteristics such as the heat release rate, yield rate of combustion product, and effective heat of combustion were quantified in terms of thickness. The tests show two peak points of HRRPUA due to lateral fire propagation in the initial stage, followed by later fire penetration through the specimen thickness. The mass loss rate of flaming combustion was 5 times higher than that of smoldering combustion, while the CO yield rate of smoldering combustion was 10 times higher than that of flaming combustion. This study can contribute to the understanding of fire behavior of wood combustibles and provide useful data for fire analysis.

• Tunnel and Underground Space
• /
• v.13 no.4
• /
• pp.287-293
• /
• 2003

A long vertical duct is an essential installation for extracting smoke to the ground level when a fire occurs in an underground space. Due to the limitations of its basic assumptions, the existing two-layer zone model is unsuitable to model smoke dispersion through a long vertical duct. Therefore, an assessment was made to investigate the applicability of the field model, which is based on the computational fluid dynamics (CFD). A similar configuration to the published experimental work was modeled to test the validity. It is clear that under a consistent decision criterion based on the mass fraction, the field model (CFD) is able to predict that the diffusion front progresses up the shaft with exactly the same rate as that in the empirical correlation equation. This result is for better than the mathematically obtained equations in previously published research. Therefore, it can be said that the field model is an excellent option to predict the smoke dispersion through the long vertical shaft.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.439-452
• /
• 1994

A method to optimize the cost of R/C frames and an algorithm of the optimal limit state design for R/C frames subjected to dynamic loads are presented. The modal superposition method was used to find the dynamic responses of the frames. Each member of R/C frame is made up of more than two elements and the stiffness matrix and consistent mass matrix of three d.o.f in the node of each element was used to include axial, shear and flexural effects. The objective function to be minimized formulated the cost of materials, steel and concrete, and optimised to satisfy the behaviors of R/C frame and each constraint imposed by the limit state requirements. Both objective function and each constraint are derived in terms of design variables which include the effective depth, beam width, compression and tension steel area, and column shear steel area. A few applications are presented which demonstrate the feasibility, the validity and efficiency of the algorithm for automated optimum design of R/C frames where dynamic behavior is to be considered.

• Journal of Korean Society of Steel Construction
• /
• v.16 no.1 s.68
• /
• pp.81-89
• /
• 2004

The vibration analysis of the circular arch as a member of a structure has been an important subject of mechanics due to its various applications to many industrial fields. In particular, circular arches with variable cross section are widely used to optimize the distribution of weight and strength and to satisfy special architectural and functional requirements. The Generalized Differential Quadrature Method (GDQM) and Differential Transformation Method (DTM) were recently proposed by Shu and Zou, respectively. In this study, GDQM and DTM were applied to the vibration analysis of circular arches with variable cross section. The governing equations of motion for circular arches with variable cross section were derived. The concepts of Differential Transformation and Generalized Differential Quadrature were briefly introduced. The non-dimensionless natural frequencies of circular arches with variable cross section were obtained for various boundary conditions. The results obtained using these methods were compared with those of previous works. GDQM and DTM showed fast convergence, accuracy, efficiency, and validity in solving the vibration problem of circular arches with variable cross section.

• Journal of Applied Biological Chemistry
• /
• v.59 no.1
• /
• pp.5-7
• /
• 2016

One of oriental medicinal plants, Potentilla chinensis, has been used for anti-inflammation, hemostatic, decryption, and antipyretic. Especially, a root of Potentilla chinensis was used as important material for oriental medication. Although several kinds of bioactive component of Potentilla chinensis extract from stems and leaves were identified, the major component of Potentilla chinensis from roots is not well established. In this study, the root of Potentilla chinensis was extracted in different solvent system and analyzed by high performance liquid chromatography (HPLC). According to HPLC analysis, a major component was isolated and its physicochemical properties were evaluated by mass spectrometry and nuclear magnetic resonance. Based on these results, isolated compound was identified as 2,3,8-Tri-O-methylellagic acid. And quantification of 2,3,8-Tri-O-methylellagic acid with different extraction solvent system was performed for industrial application.

• Applied Chemistry for Engineering
• /
• v.16 no.3
• /
• pp.427-433
• /
• 2005

The use of the microwave-assisted process for the extraction of effective constituents from ginseng was investigated at various operating conditions. The influence of solvent (ethanol-water, 50% v/v) to ginseng ratio, particle size and applied microwave power on the efficiency of extraction was examined. The microwave extraction system used was custom manufactured so that the intensity of microwave may be varied by using anode-voltage controller. It was found that the ratio of 6 : 1 (vol/mass) gave a good extraction efficiency. Small particle size gave high yield but it caused difficulties in the separation of solvent from the sludge. The higher power was no guarantee of the efficient extraction yield. The more important factor than the employed power was the adequate temperature under sufficient contact time. Using deionized-water as swelling agent, the degree of swelling of ginseng by microwave heating and conventional heating in water-bath was also studied. It was observed that the microwave heating enhanced the swelling much more than the conventional heating. It is believed that this enhanced swelling was responsible for the rapid microwave-assisted extraction rate.