• Korean Journal of Medicinal Crop Science
• /
• v.28 no.3
• /
• pp.183-194
• /
• 2020

Background: This study investigated the effect of soil properties and soil bacterial community on early growth characteristics of wild-simulated ginseng (Panax ginseng C. A. Meyer) in coniferous and mixed forest experimental fields. Methods and Results: The soil bacterial community was analyzed using a high throughput sequencing technique (Illumina MiSeq sequencing). The relationship between the soil bacterial community, soil properties, and growth characteristics of wild-simulated ginseng were analyzed using principal coordinate analysis (PCoA) and the Pearson's correlation analysis. Soil properties and soil bacterial community showed significant difference with forest physiognomy. Results of Pearson's correlation analysis and PCoA showed that the soil properties (soil pH, organic matter, total nitrogen, and cation exchange capacity) and soil bacterial community had significant correlation with tree species ratio and early growth characteristics of wild-simulated ginseng. Conclusions: This study clearly demonstrated the effect of soil properties and soil bacterial community on early growth characteristics of wild-simulated ginseng in coniferous and mixed forest. Moreover, these results will help in the selection of suitable cultivation sites for wild-simulated ginseng.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2010.05a
• /
• pp.56.2-56.2
• /
• 2010

An improvement in the optical and structural properties of p-GaN was obtained by using antimony (Sb) as a surfactant during p-GaN growth. Two different growth temperatures of p-GaN such as $1030^{\circ}C$ and $900^{\circ}C$ were considered. Keeping the growth conditions for p-GaN constant, Sb was introduced during p-GaN growth while varying the [Sb]/([Ga]+[Mg]) flow ratio. [Sb]/([Ga]+[Mg]) flow ratio will be denoted as SGM ratio for convenience. SGM ratio of 0, 0.015 and 0.03% were considered for high temperature p-GaN growth. SGM ratio of 0, 0.005, 0.01 and 0.02% were considered for low temperature p-GaN growth. The analysis results suggest that using the optimum SGM ratio during p-GaN growth greatly improves the optical and structural properties of the p-GaN.

• Journal of the Korean Ceramic Society
• /
• v.56 no.1
• /
• pp.24-36
• /
• 2019

Recently, considerable progress and many breakthroughs have been achieved in the growth of two-dimensional materials, especially transition metal dichalcogenides (TMDCs), which attract significant attention owing to their unique properties originating from their atomically thin layered structure. Chemical vapor deposition (CVD) has shown great promise to fabricate large-scale and high-quality TMDC films with exceptional electronic and optical properties. However, the scalable growth of high-quality TMDCs by CVD is yet to meet industrial criteria. Therefore, growth mechanisms should be unveiled for a deeper understanding and further improvement of growth methods are required. This review summarizes the recent progress in the growth methods of TMDCs through CVD and other modified approaches to gain insights into the growth of large-scale and high-quality TMDCs.

• Journal of Powder Materials
• /
• v.8 no.2
• /
• pp.131-135
• /
• 2001

The ferroelectric properties of barium titanate strongly depend on its microstructure, in particular, grain size and distribution. During sintering, $BaTiO_3$ usually exhibits abnormal grain growth, which deteriorates considerably the ferroelectric properties. A typical technique to suppress the abnormal grain growth is the addition of dopants. Dopant addition, however, affects the ferroelectric properties and thus limits the application of $BaTiO_3$. Here, we report a simple but novel technique to prevent the abnormal grain growth of $BaTiO_3$ and to overcome the limitation of dopant use. The technique consists of stepwise sintering in a reducing atmosphere and in an oxidizing atmosphere. The materials prepared by the present technique exhibit uniform grain size and high dielectric properties. The technique should provide opportunities of having $BaTiO_3$-based materials with superior ferroelectric properties.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.4
• /
• pp.221-237
• /
• 2005

For developing the site-specific fertilizer management strategies of crop, it is essential to know the spatial variability of soil factors and to assess their influence on the variability of crop growth and yield. In 2002 and 2003 cropping seasons within-field spatial variability of rice growth and yield was examined in relation to spatial variation of soil properties in the· two paddy fields having each area of ca. $6,600m^2$ in Suwon, Korea. The fields were managed without fertilizer or with uniform application of N, P, and K fertilizer under direct-seeded and transplanted rice. Stable soil properties such as content of clay (Clay), total nitrogen (TN), organic mater (OM), silica (Si), cation exchange capacity (CEC), and rice growth and yield were measured in each grid of $10\times10m$. The two fields showed quite similar spatial variation in soil properties, showing the smallest coefficient of variation (CV) in Clay $(7.6\%)$ and the largest in Si $(21.4\%)$. The CV of plant growth parameters measured at panicle initiation (PIS) and heading stage (HD) ranged from 6 to $38\%$, and that of rice yield ranged from 11 to $21\%$. CEC, OM, TN, and available Si showed significant correlations with rice growth and yield. Multiple linear regression model with stepwise procedure selected independent variables of N fertilizer level, climate condition and soil properties, explaining as much as $76\%$ of yield variability, of which $21.6\%$ is ascribed to soil properties. Among the soil properties, the most important soil factors causing yield spatial variability was OM, followed by Si, TN, and CEC. Boundary line response of rice yield to soil properties was represented well by Mitcherich equation (negative exponential equation) that was used to quantify the influence of soil properties on rice yield, and then the Law of the Minimum was used to identify the soil limiting factor for each grid. This boundary line approach using five stable soil properties as limiting factor explained an average of about $50\%$ of the spatial yield variability. Although the determination coefficient was not very high, an advantage of the method was that it identified clearly which soil parameter was yield limiting factor and where it was distributed in the field.

• Journal of Mechanical Science and Technology
• /
• v.14 no.10
• /
• pp.1041-1050
• /
• 2000

In this paper the effect of specimen thickness on fatigue crack growth with the spatial distribution of material properties is presented. Basically, the material resistance to fatigue crack growth is treated as a spatial stochastic process, which varies randomly on the crack surface. The theoretical autocorrelation functions of fatigue crack growth resistance with specimen thickness are discussed for several correlation lengths. Constant ${\Delta}K$ fatigue crack growth tests were also performed on CT type specimens with three different thicknesses of BS 4360 steel. Applying the proposed stochastic model and statistical analysis procedure, the experimental data were analyzed for different specimen thicknesses for determining the autocorrelation functions and probability distributions of the fatigue crack growth resistance.

• YAKHAK HOEJI
• /
• v.41 no.5
• /
• pp.571-574
• /
• 1997

We have synthesized acetylsalicylic acid derivative of eugenol. And also, physico-chemical properties and analysis on this compound were examined. The correlation coefficient of the calibration curve in methanol solution was 0.9998. The hair growth stimulation of eugenol derivative on the hair of black mouse (C57BL/6), was also carried out using Implant method. When its ethanol solution was administered to the black mouse by route of skin, eugenol derivative promoted the growth of hair.

• YAKHAK HOEJI
• /
• v.43 no.3
• /
• pp.316-319
• /
• 1999

Chrysin 7-Ο-crotonate was synthesized by condensing crotonic acid with chrysin in organic solvent, tetrahydrofuran (THF) using dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP). Its structure was indentified by NMR, MS, UV, IR etc. We also investigated the physico-chemical properties and set up the quantitative anytical method of this compound. The correlation coefficient of calibration curve measured at the isobestic point (340 nm) on this compound was approximately 0.9994 by absorption spetrophtometry. Detection limit was 1.6ng at S/N=3 by using a RP column by HPLC. The hair growth effect fo chrysin 7-Ο-crotonate on the hair of black mouse (C57BL/6), was carried out using paste method. When its ethanol solution was administered to this black mouse by route of skin, this compound promoted the growth of hair.

• Computers and Concrete
• /
• v.17 no.1
• /
• pp.107-127
• /
• 2016

Concrete is a heterogeneous material containing many weaknesses such as micro-cracks, pores and grain boundaries. The crack growth mechanism and failure behavior of concrete structures depend on the plastic deformation created by these weaknesses. In this article the non-linear finite element method is used to analyze the effect of presence of micro pore near a crack tip on both of the characteristics of crack tip plastic zone (its shape and size) and crack growth properties (such as crack growth length and crack initiation angle) under pure shear loading. The FE Code Franc2D/L is used to carry out these objectives. The effects of the crack-pore configurations and the spacing between micro pore and pre-excising crack tip on the characteristics of crack tip plastic zone and crack growth properties is highlighted. Based on the obtained results, the relative distance between the crack tip and the micro pore affects in very significant way the shape and the size of the crack tip plastic zone. Furthermore, crack growth length and crack initiation angle are mostly influenced by size and shape of plastic zone ahead of crack tip. Also the effects of pore decrease on the crack tip by variation of pore situation from linear to perpendicular configuration. The critical position for a micro pore is in front of the crack tip.

• Progress in Superconductivity and Cryogenics
• /
• v.19 no.3
• /
• pp.18-22
• /
• 2017

Addition of $BaSnO_3$ (BSO) to $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to $750^{\circ}C$ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.