• Journal of the Korean Society of Tobacco Science
• /
• v.16 no.1
• /
• pp.20-25
• /
• 1994

The volatile components were extracted from root of Cnidium officinale M. by SDE(Simultaneous steam distillation and extraction) apparatus and analyzed by GC/M.5 and GC retention index matching. The experimental results revealed the presence of over 22 volatile components. Major components were cnidilide (35.1%), neocnidilids (13.4%), ligustilide (23.2%). The essential oils were separated by silica gel column chromatography(Merck 70-230mesh), and 4 fractions among 12 fractions separated had a, good aroma character.

• Korean Journal of Environment and Ecology
• /
• v.21 no.6
• /
• pp.559-564
• /
• 2007

This research is aimed at finding out the ecological change of Seunghwanglim through the examination of vegetational change of tree seedlings of old giant trees growing at Seunghwanglim [Seunghwang Forest designated as a Natural Monument No.93] after the installation of protective iron fence. The survey results are as follows: First, as a result of keeping out people by installing a protective iron fence in 1989, soil hardness of the plane forest was greatly improved except the area used as roads. The seedlings of the plane forest, whose damage index is 2,3,4, were found to have the highest 1,202 $individuals/400m^2$, and those of the plane forest, whose damage index is 1, were revealed to have 565 $individuals/400m^2$, and those of the slope forest were found to have 403 $individuals/400m^2$. The number of the young sapling[taller than 2 meters] individuals of the plane forest whose damage index is 1 was found to be the most $48/400m^2$, and that of the plane forest whose damage index is 2, 3, 4- was $31/400m^2$, and that of the slope forest proved to be $14/400m^2$. In the plane forest whose damage index is 2, 3, 4, the saplings of the Ulmus davidiana var. japonica and Acer triflorum are relatively much distributed, and in the plane forest whose damage index is 1, many saplings of the Prunus padus and Styrax obassia, were found to grow and in the slope forest, many saplings of the Acer pictum subsp. mono and Acer pseudo-sieboldianum. were found to grow. Many seedlings of Rubus spp. - R. oldhamii, R. coreanus and R. crataegifolius. - and Akebia quinata were growing vigorously on plane forest, but they might decrease in number with the increasing number of the tree saplings.

• Journal of Life Science
• /
• v.29 no.7
• /
• pp.762-768
• /
• 2019

Doellingeria scabra Thunb. (syn. Aster scaber Thunb.), a perennial herb in the family Asteraceae, is frequently found in the wild mountain regions of Korea. This aim of this work was to measure the characteristics of patchiness of D. scabra in a local population on Mt. Maebong in Taeback-ci, Gangwon-do. The spatial distribution pattern of this species was estimated by analyzing ecological data by methods including the index of dispersion, Lloyd's mean crowding, and Morisita's index. The mean population density of the D. scabra population was 2.94. The D. scabra individuals were uniformly or randomly distributed in small-scale plots and were aggregately distributed in two large-scale plots ($16{\times}32m^2$ and $32{\times}32m^2$). The mean crowding ($M^*$) was 0.916. The mean patchiness index (PAI) was 0.796. Morisita's coefficient tended to decrease the density of the population as the plot size increased. The expected value of Eberhardt's index ($I_E$) in the local population was 2.623. Moran's I of D. scabra significantly differed from the expected value in 6 of 8 cases (75.0%). The first five classes were positive, with four showing statistical significance, indicating similarity among individuals in the first four distance classes (I-IV, 8 m), The results presented here could provide a theoretical basis for the conservation of D. scabra (Korean: chamchwi) and for the rehabilitation and sustainable management of forest ecosystems on Mt. Maebong, as well as on other mountains.

• Journal of Astronomy and Space Sciences
• /
• v.25 no.2
• /
• pp.129-138
• /
• 2008

This study attempts to show how the geomagnetic indices, AU, AL and Dst, respond to the interplanetary parameters, more specifically, the solar wind electric field VBz during southward interplanetary magnetic field (IMF) period. The AU index does not seem to respond linearly to the variation of southward IMF. Only a noticeable correlation between the AU and VBz is shown during summer, when the ionospheric conductivity associated with the solar EUV radiation is high. It is highly likely that the effect of electric field on the eastward electrojet intensification is only noticeable whenever the ionospheric conductivity is significantly enhanced during summer. Thus, one should be very cautious in employing the AU as a convection index during other seasons. The AL index shows a significantly high correlation with VBz regardless of season. Considering that the auroral electrojet is the combined result of electric field and ionospheric conductivity, the intensification of these two quantities seems to occur concurrently during southward IMF period. This suggests that the AL index behaves more like a convection index rather than a substorm index as far as hourly mean AL index is concerned. Contrary to the AU index, the AL index does not register the maximum value during summer for a given level of VBz. It has something to do with the findings that discrete auroras are suppressed in sunlight hemisphere (Newell et al. 1996), thus reducing the ionospheric conductivity during summer. As expected, the Dst index tends to become more negative as VBz gets intensified. However, the Dst index (nT) is less than or equal to 15VBz(mV/m) + 50(Bz < 0). It indicates that VBz determines the lower limit of the storm size, while another factor(s), possibly substorm, seems to get further involved in intensifying storms. Although it has not been examined in this study, the duration of southward IMF would also be a factor to be considered in determining the size of a storm.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.23 no.1
• /
• pp.109-117
• /
• 2011

It was calculated using empirical formulas for the weight of Tetrapod, which was a representative armor unit in the rubble mound breakwater in Korea. As the formulas were evaluated from a curve-fitting with the result of hydraulic test, the uncertainty of experimental error was included. Therefore, the neural network and M5' model tree were used to minimize the uncertainty and predicted the stability number of armor block. The index of agreement between the predicted and measured stability number was calculated to assess the degree of uncertainty for each model. While the neural network with the highest index of agreement have an excellent prediction capability, a significant disadvantage exists that general designers can not easily handle the method. However, although M5' model tree has a lower prediction capability than the neural network, the model tree is easily used by the designers because it has a good prediction capability compared with the existing empirical formula and can be used to propose the formulas like an empirical formula.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.24 no.1
• /
• pp.46-51
• /
• 2014

Objectives: The principal aim of this study was to compare the concentrations of gaseous pollutants emitted in enclosed pig buildings between different rates of general ventilation and determine the variations in the patterns of gaseous pollutants as affected by ventilation rate. Materials and Methods: The experiment was performed in the growing/finishing room($20.0m{\times}12.0m{\times}3.0m$) of a pig confinement building located on the experimental farm of Seoul National University. The conditions of the general ventilation rate for three treatments were 30%($4.12m^3s^{-1}$), 50%($6.87m^3s^{-1}$) and 70%($9.61m^3s^{-1}$). The data presented in the study were collected overa total of 45 days, 15 days for each of the three treatments from March to May 2011. A total of six air samplings were taken at 1.5m above the floor of the pig building. The environmental agents measured in the pig building were ammonia, hydrogen sulfide and odor concentration index for gaseous pollutants with temperature and hydrogen sulfide for thermal factors. Results: There were significant differences in the ammonia and odor concentration index in the pig building among the three general ventilation rate conditions(p<0.05), whereas hydrogen sulfide did not show a significant difference among three conditions of general ventilation rate(p>0.05). As the general ventilation rate applied to the pig building increases, it appears that all the indoor environmental agents measured in this study simultaneously decrease. Conclusions: The gaseous pollutants significantly affected by the general ventilation rate in pig building were ammonia and odor concentration index(p<0.05). However, it was found that hydrogen sulfide and thermal factors, temperature and relative humidity were not influenced significantly by variation in the general ventilation rate.

• Journal of Korea Water Resources Association
• /
• v.32 no.4
• /
• pp.489-499
• /
• 1999

This research investigated the applicapability of an improved algorithm to calculate the topographic index, ln($\alpha$/tan B), for the topography of Korea employing channel initiation threshold area(CIT) and an exponent for the gradient(H). hanjaechun subwatershed in Cheongdochun and Dongok subwatershed in Wichun test watershed were selected as study areas. The digital elevation models(DEM) of study areas have been made with the resolution from 10m to 100m. Application of CIT to the traditional algorithm provide reasonable computation method in considering channel pixel impact. Introduction of the gradient exponent(H) made it possible to obtain better flow convergence effect in concave topography comparing with the traditional multiple flow direction algorithm. The improved algorithm shows the capability to relax the overestimation problem of rising limb of hydrograph through reducing overestimated high value of topographic index.

• Journal of Chest Surgery
• /
• v.22 no.4
• /
• pp.601-608
• /
• 1989

We sought the relationship between the pulmonary artery development and cardiac performance from the analysis of the 36 cyanotic congenital heart disease patients [mainly TOF] who were operated and indwelled the pulmonary artery and left atrial pressure monitoring catheters for the postoperative care at the department of Thoracic and Cardiovascular Surgery SNUH in 1988. They were pre-evaluated of the pulmonary artery index from the cineangiographic films and post-operatively, calculated the cardiac index from the arterial and mixed venous blood gas and also measured the mean left atrial pressure and total inotropic supporting amount after operation. The post-operative cardiac indices were 3.46 * 1.03 1/min/M2 [immediate postoperative], 3.31 [ 1.08 [postoperative 6 hrs], 3.29 [ 1.01 [12 hrs], 3.54 * 1.02 [24 hrs], 3.92 * 1.14 [48 hrs], respectively. We divided the patients the group A and group B from the size of the pulmonary artery index, that is, group A was below 200 mm2/M2 and group B above 200 mm2/M2 of the pulmonary artery index. The cardiac indices and left atrial pressure between the group A and B were not different in the view of the statistical significance but the total post-operative inotropic amount of group A was more than group B and it was significant statistically. We concluded that the smaller the pulmonary artery index is, the more postoperative supportive treatment [for example, inotropics] for the enhancement of cardiac performance is needed, and indirectly, which means that the pulmonary artery index was correlated with the postoperative cardiac performance in cyanotic congenital heart disease.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.14 no.5
• /
• pp.571-577
• /
• 1989

In this paper, the double-refractive index profile, which is generalized a trapezoidal index profile, is proposed to study the characteristics of a optical fiber in the wave length 1.55um. Being compared with a triangle profile, it has many advantages over an optimum core radius, the minimum refractive index difference and the change of chromati dispersion characteristics with wavelength. Though the value of a varies from 2 to infinite, the same results are approximately obtained. Therefore, in fabrication of a fiber, the step part of trapezoidal index profile can replace the profile of a-power refractive index. Because the refractive index presented in this paper varies with a, it can be applied to multiple cladding fiber or segmented core fiber. And it is expected that the characteristics of the fiber are obtained.

• Journal of Information Science Theory and Practice
• /
• v.2 no.4
• /
• pp.20-30
• /
• 2014

This study examines the foremost concerns related to most noted research performance index. The most popular and widely acceptable h-index underestimates the highly visible scientist, the middle order group, due to citation distribution issues. The study addresses this issue and uses 'Corrected Quality Ratio' (CQ) to check the implicit underpinnings as evident in h-index. CQ helps to incorporate the aspects of a good research performance indicator. This simple revision performs more intimately and logically to gauge the broader research impact for all groups and highly visible scientists with less statistical error.