• Journal of the Korean Wood Science and Technology
• /
• v.45 no.4
• /
• pp.463-470
• /
• 2017

The objectives of this study are to obtain the basic knowledge of anatomical characteristics and wood properties of thinning trees of young teak (Tectona grandis L.F.) for fulfill the timber demand in Indonesia. Nine thinning trees of 5-year-old teak clone trees were used for analyzing the cell morphology and air-dry density. Vessel diameters in pore and outer pore zones were 165 and $90{\mu}m$, respectively. Mean value of fiber diameter, cell wall thickness, and fiber length in outer pore zone were $14.6{\mu}m$, $2.07{\mu}m$, and 1.04 mm, respectively. In addition, mean value of air-dry density was $0.55g/cm^3$. The measurement and values of vessel diameter, fiber diameter, cell wall thickness, fiber length and air-dry density in the experimental had lower than those in the older teak. Therefore, it could be suggested that the wood from thinning young teaks was not appropriate as construction material, but it could be used for furniture which do not need high of strength properties. Furthermore, since the measurements values of anatomical characteristics were still increasing from pith to bark, it could be suggested that 5-year-old teak clones are still in a juvenile phase. Positively significant correlations were found between air-dry density and cell wall thickness, indicating that cell wall thickness is strongly correlated with wood density of teak.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.117-119
• /
• 2002

In this paper, the geometry effectiveness and contact modes as functions of real contact length on a cap ring have been analyzed for high pressure sealing mechanism in reciprocating actuator. The reaction force and elastic strain energy density are very important parameters for analyzing the sealing performance of an ACGT ring seal. For the high pressure of 800bar and the maximum speed of 3m/s, the main piston is reciprocating along the linear line against the cylinder wall. The computed results indicate that the length ratio of a cap ring is more influential design parameter compared to that of the tribological contact mode. Thus, this paper recommends the discrete contact area rather than a conventional flat contact model. Especially, the sealing capacity is more improved when the length ratio of a cap ring is below 0.625.

• Journal of the Korean Applied Science and Technology
• /
• v.31 no.4
• /
• pp.653-662
• /
• 2014

This study was determined the hair growth effect and mode of action of a complex extract (abelmo), extracted from various natural plants including Acorus calamus var. angustatus. 30 six-week old C57BL/6 mice were randomly assigned into three treatment groups with ten mice per treatment group repeatedly. The treatment group is a control group, and was classified into saline-applied, minoxidil 5%-applied, and abelmo-applied groups. Hair growth started from the abelmo-applied and minoxidil 5% -applied groups on the 9th day, compared to the saline-applied group. Hair growth rate was 17.06% and 19.15% in those two groups, respectively, and the abelmo-applied group's hair growth rate was higher. The density, length and thickness of hair were significantly higher in the order of abelmo-applied group, minoxidil 5%-applied group and saline-applied group on the 9th day, and hair root was strongly maintained in the abelmo-applied group. The density, length and thickness of hair in the abelmo-applied group were significantly higher by 599.8, 122.2 and 181.8% on the 9th day compared to the saline-applied group, and 166.7, 171.4 and 200.2% on the 12th day, and 136.6, 216.9 and 180.7%, respectively on the 15th day. As for hair follicle and the length of hair shaft from the dosal skin histopathology manifestation, the abelmo-applied group was more excellent than the saline-applied group and minoxidil 5%-applied group. This result actually confirmed the fact that abelmo promotes hair growth and strongly maintains hair root simultaneously.

• 전기의세계
• /
• v.29 no.8
• /
• pp.511-518
• /
• 1980

The thermostimulated discharge currents of low-density polyethylene electrets were measured versus the principal experimental variables. Several electrode types were used for the charging and discharging procedures. The results led to know the experimental conditions for the heterocharge and homocharge accumulating and decreasing. The electronic structure parameters of polyethylene such as trap level, density of traps, hopping length, mobility, trap time constants were deduced. A method for evaluating the local electric field inside the electret is proposed.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.101-101
• /
• 2022

In recent years, due to climate change, the livestock industry has become more interested in the production of forage crops. In Korea, more than 74% of forage crops are cultivated in winter rice fields. In particular, Italian ryegrass (IRG) is depends on imports for more than 70% of its seeds. In generally, the IRG rapeseed cultivation method involves sowing from early October to mid-October by drill sowing seeding or spot seedling. However, the sowing period is delayed due to frequent rainfall during. And, same period require a lot of seeds. However, raising seedlings and transplanted IRG will overcome weather conditions and reduce the amount of seeds. This study was intended to be applied to the domestic IRG seed industry in the future through growth and quantity evaluation according to transplant time and planting density for the production of good quality IRG seeds in rice paddy fields. In this study, transplanting time (October 20, October 30, November 10) and planting density (50, 70, and 80) were cultivated at the National Institute of Crop Science in 2021. The amount of fertilizer applied was adjusted to (N-P₂O₅-K₂O) 4.5-12-12 (kg/10a), and then 2.2(kg/10a) of nitrogen was added each year. For the growth survey, leaf area, canopy coverage, plant length, and seed yield were investigated. Along with the transplanting time, the plant length was higher on October 20 than on October 30 and November 10. On the other hand, leaf area index changes differed depending on the transplanting time and planting density, and were particularly high on October 20, 80 density and 70 density, but similar on October 30 and November 10. 1000 seed weight showed no difference with transplanting time and planting density. On the other hand, the seed yield was 215(kg/10a) for 80 density on October 20, 211(kg/10a) for 70 density, 118(kg/10a) for 50 density, and 80 density for October 30 and November 10. and 70 density did not differ. On the other hand, the 50 density on October 30 and November 10 were 164(kg/10a) and 147(kg/10a) respectively. As can be seen from this study, the earlier the transplant, the higher the seed yield. However, the 50 density was reduced in yield compared to the 70 density and 80 density.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.3
• /
• pp.223-230
• /
• 2010

To compare seed collection and the growth of Anadara subcrenata in Suncheon and Boseong Bays, environmental factors and the growth of larvae and spats were investigated from August 2008 to July 2009 in commercial farming sites in both bays. The variation in water temperature in both bays was similar, but the salinity was lower in Suncheon Bay than in Boseong Bay. The chlorophyll-a content was higher in Suncheon Bay due to the large inflow of freshwater. The density and shell length of A. subcrenata larvae did not differ significantly between the two bays. However, the relative growth of shell height to shell length was significantly higher in Suncheon Bay (P<0.05). The growth of A. subcrenata spats attached to a collector was significantly faster in Suncheon Bay (P<0.05). The spats in Suncheon and Boseong Bays grew to 24.3 and 21.0 mm in shell length, respectively, within 1 year after spawning, and the shell length reached 35.6 and 34.8 mm, respectively, within 2 years of spawning. The initial spats density was higher in Boseong Bay, but the growth of spats was better in Suncheon Bay. The faster growth of A. subcrenata in Suncheon Bay can be explained by the high chlorophyll-a content in this bay. Based on the low survival (%) and slower growth rate of spats in Boseong Bay, the commercial culture density of A. subcrenata in Boseong Bay should be reduced to the optimum level of the carrying capacity.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.64 no.1
• /
• pp.33-39
• /
• 2019

The goal of this study was to investigate how the characteristics of growth and yield are affected by various planting densities in wide-row drill seeding cultivation suitable for mechanized harvesting. Two cultivars ('Hwanggeum' and 'Leebackchal') of proso millet (Panicum miliaceum L.) were planted at varying planting densities [row spacing (20, 30, and 50 cm) and plant spacing (3, 5, 10, and 15 cm)]. The culm length was highest at the planting density of $50{\times}3cm$ and $50{\times}5cm$ for 'Hwanggeum' and $20{\times}3cm$ for 'Leebackchal'. The culm diameter became thinner as the planting density increased. The number of tillering and panicle length showed the same tendency to increase in quantity or length as planting density decreased and was highest at $50{\times}15cm$ when the planting density was lowest. The number of seeds per individual increased as planting density decreased. The thousand grain weight showed no significant differences among treatment plots. The greatest yield of 'Hwanggeum' was obtained at a planting density of $50{\times}3cm$ ($314.9kg{\cdot}10a^{-1}$) and that of 'Leebackchal' was obtained at $50{\times}3cm$ and $50{\times}5cm$ ($358-356kg{\cdot}10a^{-1}$).

• Current Photovoltaic Research
• /
• v.2 no.2
• /
• pp.59-62
• /
• 2014

Minority carrier diffusion length is one of the most important parameters of solar cells, especially for short circuit current density (Jsc). In this report, we proposed the calculating method of the minority carrier diffusion length ($L_n$) in CIGS solar cells through biased quantum efficiency (QE). To verify this method's reliability, we chose two CIGS samples which have different grain size and calculated $L_n$ for each sample. First of all, we calculated out that $L_n$ was 56nm and 97nm for small and large grain sized-cell through this method, respectively. Second, we found out the large grain sized-cell has about 7 times lower defect density than the small grain sized-cell using drive level capacitance profiling (DLCP) method. Consequently, we confirmed that $L_n$ was mainly affected by the micro-structure and defect density of CIGS layer, and could explain the cause of Jsc difference between two samples having same band gap.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.627-634
• /
• 2002

To facilitate a drilling plan for grouting in fractured rock, an algorithm of practical use associated with a new term “fracture density distribution”or“fracture tomogram”is developed. It is well known that Televiewer data(amplitude and traveltime image) provide detailed information about not only dip and dip direction of each fracture but also its aperture size estimated by an appropriate evaluation algorithm. A selected plane section of medium around a borehole or the cross section between two boreholes is discretized into a two dimensional grid of cells(rectangular elements). As each elongated(straight) fracture passes through the cells, the corresponding aperture size value is successively summed up in each cell, depending on the fracture length segment. In this, the fracture lines can be determined by intersecting of each fracture plane with the selected plane section. If the fracture line does not pass through a particular grid element, the segment length is set to zero. The final value(aperture size value of each cell) derived from all the detected fractures constitutes the fracture density distribution of the selected plane section, Field examples are illustrated, which will prove the benefit of the suggested algorithm for several kinds of grouting works.

• Applied Microscopy
• /
• v.44 no.2
• /
• pp.74-78
• /
• 2014

Dislocation density and distribution in epitaxial GaAs layer on Si are evaluated quantitatively and effectively using image processing of transmission electron microscopy image. In order to evaluate dislocation density and distribution, three methods are introduced based on line-intercept, line-length measurement and our coding with line-scanning method. Our coding method based on line-scanning is used to detect the dislocations line-by-line effectively by sweeping a thin line with the width of one pixel. The proposed method has advances in the evaluation of dislocation density and distribution. Dislocations can be detected automatically and continuously by a sweeping line in the code. Variation of dislocation density in epitaxial GaAs films can be precisely analyzed along the growth direction on the film.