• Natural Product Sciences
• /
• 제24권4호
• /
• pp.229-234
• /
• 2018

Ginseng products available in different forms and preparations are reported to have varied bioactivities and chemical compositions. In our previous study, four new dammarane-type ginsenosides were isolated from Panax ginseng, which are ginsenoside Rg18 (1), 6-acetyl ginsenoside Rg3 (2), ginsenoside Rs11 (3), and ginsenoside Re7 (4). Accordingly, the goal of this study was to determine the distribution and content of these newly characterized ginsenosides in different ginseng products. The content of compounds 1 - 4 in different ginseng products was determined via HPLC-UV. The samples included ginseng roots from different ginseng species, roots harvested from different localities in Korea, and samples harvested at different cultivation ages and processed under different manufacturing methods. The four ginsenosides were present at varying concentrations in the different ginseng samples examined. The variations in their content could be attributed to species variation, and differences in cultivation conditions and manufacturing methods. The total concentration of compounds 1 - 4 were highest in ginseng obtained from Geumsan ($185{\mu}g/g$), white-6 yr ginseng ($150{\mu}g/g$), and P. quinquefolius ($186{\mu}g/g$). The results of this study provide a basis for the optimization of cultivation conditions and manufacturing methods to maximize the yield of the four new ginsenosides in ginseng.

• Natural Product Sciences
• /
• 제25권2호
• /
• pp.111-114
• /
• 2019

The herbal formula, DF-02, consisting of Ephedra intermedia and Rheum palmatum are used for the treatment of the metabolic diseases such as obesity and liver fibrosis in Korean local clinics. We aimed to develop the simultaneous analytical conditions for four standards, (+)-pseudoephedrine (PSEP) and (-)-ephedrine (EP) for E. intermedia, and aloe-emodin (AE) and chrysophanol (CP) for R. palmatum using HPLC-UV techniques. The validated conditions yielded the high precision (relative standard deviation (RSD) < 3.65%) and the recoveries (94 - 106%) using the calibration curves with high linearity ($R^2$ > 0.9994). As a result, four standards of DF-02 were simultaneously determined under the developed method, which will be utilized for the quality control or evaluation of DF-02 and many herbal preparations containing E. intermedia and R. palmatum.

• Advances in nano research
• /
• 제11권6호
• /
• pp.621-640
• /
• 2021

Effect of thickness stretching on mechanical behavior of functionally graded (FG) carbon nanotubes reinforced composite (CNTRC) laminated nanoplates resting on elastic foundation is analyzed in this paper using a novel quasi 3D higher-order shear deformation theory. The key feature of this theoretical formulation is that, in addition to considering the thickness stretching effect, the number of unknowns of the displacement field is reduced to four, and which is more than five in the other models. Single-walled carbon nanotubes (SWCNTs) are the reinforced elements and are distributed with four power-law functions which are, uniform distribution, V-distribution, O-distribution and X-distribution. To cover various boundary conditions, an analytical solution is developed based on Galerkin method to solve the governing equilibrium equations by considering the nonlocal strain gradient theory. A modified two-dimensional variable Winkler elastic foundation is proposed in this study for the first time. A parametric study is executed to determine the influence of the reinforcement patterns, power-law index, nonlocal parameter, length scale parameter, thickness and aspect ratios, elastic foundation, thermal environments, and various boundary conditions on stresses, displacements, buckling loads and frequencies of the CNTRC laminated nanoplate.

• Steel and Composite Structures
• /
• 제18권1호
• /
• pp.91-120
• /
• 2015

A refined higher-order shear deformation theory for bending, vibration and buckling analysis of functionally graded sandwich plates is presented in this paper. It contains only four unknowns, accounts for a hyperbolic distribution of transverse shear stress and satisfies the traction free boundary conditions. Equations of motion are derived from Hamilton's principle. The Navier-type and finite element solutions are derived for plate with simply-supported and various boundary conditions, respectively. Numerical examples are presented for functionally graded sandwich plates with homogeneous hardcore and softcore to verify the validity of the developed theory. It is observed that the present theory with four unknowns predicts the response accurately and efficiently.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 추계학술대회논문집
• /
• pp.211-216
• /
• 2003

Weld line in injection molded part is one of the defect in injection molding process. Weld line deteriorates not only appearance quality but mechanical property. In this study weld line strength has been examined according to the injection operational conditions, materials and mold designs. PC and PP were used, and four different specimens were used in this experiment. Weld line strength decreased as injection temperature increases for PC. It was more dependent on mold temperature than injection temperature for PP Among the four different specimens, uneven thickness specimen showed the highest weld line strength.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2009년 춘계학술대회논문집
• /
• pp.165-169
• /
• 2009

The effect of the Dirichlet boundary condition for the redistance equation of level set method on the solutionof sloshing problem is investigated by adopting four Dirichlet boundary conditions. For the solution of the incompressible Navier-Stokes equations, P1P1 four-step fractional finite element method is employed and a least-square finite element method is used for the solutions of the two hyperbolic type equations of level set method; advection and redistance equation. ALE (Arbitrary Lagrangian Eulerian) method is used to deal with a moving computational domain. It has been shown that the free surface motion in a sloshing tank is strongly dependent on the type of the Dirichlet boundary condition and the results of broken dam and sloshing problems using various Dirichlet boundary conditions are discussed and compared with the existing experimental results.

• 한국식품영양과학회지
• /
• 제27권6호
• /
• pp.1132-1136
• /
• 1998

The optimum mixing conditions of kochujang(persimmon kochujang) added persimmon puree was optimized by four dimensional response surface methodology. The organoleptic color of persimmon kochujang showed the maximum score in 86.74g red pepper powder, 133.51g persimmon puree and 26.31g salt. The organoleptic aroma persimmon kochujang showed the maximum score in 83.48g red pepper powder, 135.38g persimmon puree and 24.50g salt. The organoleptic taste of persimmon ko chujang showed the maximum score in 85.09g red pepper powder, 133.61g persimmon puree and 25.57g salt. The overall palatability of persimmon kochujang showed the maximum score in 82.99g red pepper powder, 133.10g persimmon puree and 25.47g salt. The optimum mixing conditions for overall orga noleptic properties of persimmon kochujang were 83.00g red pepper powder, 133.00g persimmon puree and 25.00g salt.

• 한국자동차공학회논문집
• /
• 제3권1호
• /
• pp.143-154
• /
• 1995

This study investigates the response characteristics of a four-cylinder four-stroke turbocharged diesel engine by using computer simulation and experiments when a rapid acceleration is applied to the fuelpump rack. In the theoretical analysis, linearization method is used to avoid the difficulty on the complex nonlinear functions. Comppressor exit pressure, pressure and temperature of turbine inlet, and turbocharger speed are chosen as the independent variables of transfer functions which represent the dynamic characteristics of the turbocharger system, and expressed as the functions with respect to the time. Experiments on the same eigine system are also carried out to prove the validity of theoretical study. Further, this study carried an experiment for improving transient response performance by injecting air into the inlet manifold under the rapid accelerating conditions. The effects of air injection on the response performances are also represented at varying conditions such as injection pressure, injection period, accelerating rate, accelerating time, engine speed and load.

• 소성∙가공
• /
• 제20권1호
• /
• pp.54-59
• /
• 2011

Optical properties in injection molded plastic lenses for mobile phone camera have been simulated using commercial program, 3D TIMON. Four plastic lenses are being used in mobile phone camera. The quality of photographs taken by mobile phone camera is strongly depends upon optical characteristics of lenses. The variety of optical properties has been investigated according to the injection conditions through the computer simulation. Consequently optimal injection conditions for four lenses have been determined and simulation results of birefringence have been compared with experiments.

• 한국환경과학회지
• /
• 제5권2호
• /
• pp.113-130
• /
• 1996

Diurnal variations of air quality for each season over Taeau city were analyzed using the characteristic features of the various synoptic wind fields. The air quality data which were monitored by four stations are the hourly averaged sulfur dioxide($SO_2$), total suspended particulate(TSP) and oxidants ($O_3$) during the period of 1989 to 1992. The various synoptic wind fields obtained from the 850 hPa geopotential height were divided in to four geostrophic wind directions and two geostrophic wind speeds for each seasons. The synoptic weather conditions were again subdivided info two categories using the lotal cloud amounts, The results shows that diurnal and seasonal variations of the air quality over Taegu city, such as sulfur dioxide, total suspended particulate and oxidants reseal the various characteristics under the same synoptic weather conditions.