• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.600-609
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• 2019

This study was conducted to highlight the necessity for a stand density control management plan in consideration of the shape ratio of Pinus densiflora and Larix kaempferi in Korea. A total of 2,112 Pinus densiflora samples and 2,030 Larix kaempferi samples were cut, and their diameter at breast height (DBH), height, and clear length were measured for regional shape ratio (height/DBH) comparison and analysis.The shape ratio of Pinus densiflora was 72.3% in the Gangwon district, 64.0% in the central district, and 70.8% on average, indicating a higher percentage of Pinus densiflora in Gangwon than in the central area. Regionally, Yeongju had the highest percentage at 78.4%, with Yeongwol indicating 77.5%. Measured by diameter, results showed a presence of 90.4% for small diameter trees (6-16 cm), 71.7% for medium diameter trees (18-28 cm), and 56.1% for large diameter trees (30 cm). As density increased, the shape ratio of height to tree trunk diameter also increased; below 70% indicated a more stable trunk, while a result above 80% indicated trunks prone to wind hazards and snowstorms, and, therefore, the need for density control in partial areas. The overall shape ratio of Larix kaempferi was 90.6%. Pyeongchang indicated a 108.5% ratio, Yeongju 105.4%, and Danyang 100.5%, respectively.According to diameter class, small diameter trees showed 104.9% occurrence, medium diameter trees 92.7%, and large diameter trees 73.4%. The shape ratio of Larix kaempferi was higher than 80% overall, indicating vulnerability to wind hazards and snowstorms. Therefore, appropriate stand density management is required.

• Composites Research
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• v.37 no.3
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• pp.209-214
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• 2024

Graphene oxide (GO), known for its high stiffness, thermal conductivity, and electrical conductivity, is being utilized as a reinforcement in nanocomposite materials. This study evaluates the mechanical properties of epoxy nanocomposites incorporating GO and edge modified GO (E-GO), which has hydroxyl groups substituted only on its edges. GO/E-GO was uniformly dispersed in epoxy resin using ultrasonic dispersion, and mechanical properties were assessed through tensile testing. The results showed that the addition of nanoparticles increased both tensile strength and toughness. The tensile strength of the epoxy without nanoparticles was 74.4 MPa, while the highest tensile strength of 90.7 MPa was observed with 0.3 wt% E-GO. Additionally, the modulus increased from 2.55 GPa to 3.53 GPa with the addition of nanoparticles. Field emission scanning electron microscopy of the fracture surface revealed that the growth of cracks was impeded by the nanoparticles, preventing complete fracture and causing the cracks to split in multiple directions. E-GO, with surface treatment only on the edges, exhibited higher mechanical properties than GO due to its superior dispersion and surface treatment effects. These results highlight the importance of nanoparticle surface treatment in developing high-performance nanocomposite materials.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.53-68
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• 1969

The nutriophysiological response of rice plant to root environment was investigated with eye observation of root development and rhizosphere in situation. The results may be summarized as follows: 1) The quick decomposition of organic matter, added in low yield soil, caused that the origainal organic matter content was reached very quickly, in spite of it low value. In high yield soil the reverse was seen. 2) In low yield soil root development, root activity and T/R value were very low, whereas addition of organic matter lowered them still wore. This might be contributed to gas bubbles around the root by the decomposition of organic matter. 3) Varietal difference in the response to root environment was clear. Suwon 82 was more susceptible to growth-inhibitine conditions on low-yield soil than Norin 25. 4) Potassium uptake was mostly hindered by organic matter, while some factors in soil hindered mostly posphorus uptake. When the organic matter was added to such soil, the effect of them resulted in multiple interaction. 5) The root activity showed a correlation coeffieient of 0.839, 0.834 and 0.948 at 1% level with the number of root, yield of aerial part and root yield, respectively. At 5% level the root-activity showed correlation-coefficient of 0.751, 0.670 and 0.769 with the uptake of the aerial part of respectively. N, P and K and a correlation-coefficient of 0.729, 0.742 and 0.815 with the uptake of the root of respectively N.P. and K. So especially for K-uptake a high correlation with the root-activity was found. 6) The nitrogen content of the roots in low-yield soil was higher than in high-yield soil, while the content in the upper part showed the reverse. It may suggest ammonium toxicity in the root. In low-yield soil Potassium and Phosphorus content was low in both the root and aerial part, and in the latter particularly in the culm and leaf sheath. 7) The content of reducing sugar, non-recuding sugar, starh and eugar, total carbohydrates in the aerial part of plants in low yield soil was higher than in high yield soil. The content of them, especially of reducing sugar in the roots was lower. It may be caused by abnormal metabolic consumption of sugar in the root. 8) Sulfur content was very high in the aerial part, especially in leaf blade of plants on low yield soil and $P_2O_5/S$ value of the leaf blade was one fifth of that in high yield soil. It suggests a possible toxic effect of sulfate ion on photophosphorization. 9) The high value of $Fe/P_2O_5$ of the aerial part of plants in low yield soil suggests the possible formation of solid $Fe/PO_4$ as a mechanical hindrance for the translocation of nutrients. 10) Translocation of nutrients in the plant was very poor and most nutrients were accumulated in the root in low yield soil. That might contributed to the lack of energy sources and mechanical hindrance. 11) The amount of roots in high yield soil, was greater than that in low yield soil. The in high-yield soil was deep, distribution of the roots whereas in the low-yield soil the root-distribution was mainly in the top-layer. Without application of Nitrogen fertilizer the roots were mainly distributed in the upper 7cm. of topsoil. With 120 kg N/ha. root were more concentrated in the layer between 7cm. and 14cm. depth. The amount of roots increased with the amount of fertilizer applied.

• Korean journal of applied entomology
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• v.57 no.1
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• pp.7-13
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• 2018

Currently, there is no available tool that rapidly diagnoses pine wood nematode (PWN)-infected pine trees in the field. In this study, we synthesized and purified PWN Galectin, which might be an antigen specific to PWN, using the Baculovirus expression system. We used PWN Galectin as an antigen for generating 1,464 fusion hybridoma cell lines secreting monoclonal antibodies (Mabs). Among them, we selected 62 fusion hybridoma cell lines showing high reactivity to PWN Galectin. We further selected 12 fusion hybridoma cell lines showing high reactivity to the standard PWN-infected pine tree phosphate buffered saline (PBS) extract. Additionally, two fusion hybridoma cell lines showing no or extremely low reactivity were used as controls. The selected fusion hybridoma cell lines were subjected to limiting dilutions for selecting and establishing Mab-secreting cell lines showing higher reactivity to the standard PWN-infected pine tree extract than to the standard normal pine tree PBS extract. Moreover, the selected fusion hybridoma cell lines were further selected based on their higher reactivity to PWN protein extracts than to three non-pathogenic nematode protein extracts. The Mab-secreting cell lines established in this study could be used to develop rapid diagnostic tools that can be used in the field or in laboratories for detecting PWN-infected pine trees or PWN.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.250-254
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• 2011

We have synthesized bluish-green, highly-efficient $BaSi_2O_2N_2:Eu^{2+}$ and $(Ba,Sr)Si_2O_2N_2:Eu^{2+}$ phosphors through a conventional solid state reaction method using metal carbonate, $Si_3N_4$, and $Eu_2O_3$ as raw materials. The X-ray diffraction (XRD) pattern of these phosphors revealed that a $BaSi_2O_2N_2$ single phase was obtained. The excitation and emission spectra showed typical broadband excitation and emission resulting from the 5d to 4f transition of $Eu^{2+}$. These phosphors absorb blue light at around 450 nm and emit bluish-green luminescence, with a peak wavelength at around 495 nm. From the results of an experiment involving Eu concentration quenching, the relative PL intensity was reduced dramatically for Eu = 0.033. A small substitution of Sr in place of Ba increased the relative emission intensity of the phosphor. We prepared several white LEDs through a combination of $BaSi_2O_2N_2:Eu^{2+}$, YAG:$Ce^{3+}$, and silicone resin with a blue InGaN-based LED. In the case of only the YAG:$Ce^{3+}$-converted LED, the color rendering index was 73.4 and the efficiency was 127 lm/W. In contrast, in the YAG:$Ce^{3+}$ and $BaSi_2O_2N_2:Eu^{2+}$-converted LED, two distinct emission bands from InGaN (450 nm) and the two phosphors (475-750 nm) are observed, and combine to give a spectrum that appears white to the naked eye. The range of the color rendering index and the efficiency were 79.7-81.2 and 117-128 lm/W, respectively. The increased values of the color rendering index indicate that the two phosphor-converted LEDs have improved bluish-green emission compared to the YAG:Ce-converted LED. As such, the $BaSi_2O_2N_2:Eu^{2+}$ phosphor is applicable to white high-rendered LEDs for solid state lighting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.4
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• pp.435-445
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• 1997

The effects of temperature, prechilling, chemicals such as $GA_3$, IAA, kinetin and $KNO_3$ on the germinability of Foeniculum vulgare seed of medicinal plant were examined. In Foeniculum vulgare, the germination rate appeared to be around 50~60% or more in general, showing no differences in germination rate with different temperatures, promoting substances, physical or chemical treatments, and prechilling treatments. The observation of embryo under stereoscopic microscope for Foeniculum vulgare in Umbelliferae showed that seeds with or without embryo was almost the same in number. This result suggests that the lower rate of germination in this species is caused by embryolessness of seeds. The straight-shaped embryos as well as Y-shaped embryos were also observed. Foeniculum vulgare of medicinal plants in Umbelliferae were observed under scanning electron microscope, and did not show any opening problem near micropyle area. Final count should be made on 7th day of germination test.

• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.223-238
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• 2001

Longitudinal distribution of the fish fauna of the 20 main channel and tributary sites in the Nakdong River was investigated from July 1999 to December 2000. A total of 4,791 individuals of fisHes were collected from three to seven sampling programs of all study sites and 48 species of 17 families were collected. Dominant family was Cyprinidae (25 species, relative abundance (RA): 91.8%). Zacco platypus (RA: 18.0%) was found to be the most abundant inhabitant. Subdominant species were Opsariichthys bidens (17,1%), Squalidus chankaensis tsuchigae (13.2%), Hemibarbus labeo (9.9%), and Z. temmincki (8.2%). Among the total species, 12 species were identified as endemic species (4 families, 24.5% of 1,172 individuals). Four exotic fishes were collected (Carassius cuvieri, 25 indv.; Micropterus salmoides, 214 indv.; Lipomis macrochirus, 14 indv.; Oreochromis niloticus, 6 indv.). M. salmoides was distributed in mid to lower part of the Nakdong River. As the result of cluster analysis, sampling sites were divided into three groups (upper, middle and lowerpart). Site below Gumi (St. 10) were considered as the lower part of the Nakdong River. Combined with previous surveys, about 80 species are present in the main channel and tributaries of the Nakdong River. Since the middle of 1990s, population density of the M. salmoides rapidly increased in the stagnant lower part of the river(RA 8.8% in lower 5 sites). The feeding strategy of M. salmoides was "generalized" on Daphnia sp. (<100 mm), and "specialization" about Cladocera (<150 mm) and Insecta(<200 mm).

• Journal of Korean Association for Spatial Structures
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• v.24 no.1
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• pp.47-55
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• 2024

The aim of this study is to evaluate the possibility of damage to cultural assets resulting from vibrations generated by construction vehicle traffic. The cultural heritage's natural vibration frequency was determined to be 150Hz by measurement. The damping ratios were calculated as 4.7% using the logarithmic decrement approach and 4.3% using the half-power method. The vibration measurements obtained during vehicle operation indicated that, despite an increase in vehicle velocity of up to 15 km/h, the vibrations remained below the detectable level of 0.13 mm/sec. When the road is curved and the terrain is sloped, a suitable speed for vehicle operation was found to be around 17 km/h, at which point vibrations were seen. The highest recorded vibration amplitude at this velocity was 0.217 mm/sec, which remains below the stringent regulation limit of 2 mm/sec. Thus, it can be concluded that there is no actual harm caused by vibrations.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.6
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• pp.853-862
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• 2011

We reproduced and investigated the quality characteristics of Samhaeju (one type of Korean traditional rice wine), which has been described in ancient documents. During fermentation, the room temperature was $9.1{\sim}25.0{\circ}C$, and each treatment's material temperature was $11.7{\sim}23^{\circ}C$. As the fermentation proceeded, the pH rapidly decreased (initial pH was 6.6~6.9) and rose gradually from the 18th day. Titratable acidity and amino acidity slowly increased in general. Regarding soluble solid contents, there were various change patterns depending on the production method, and they were affected by initial room temperature. In the treatments using 1 (Sang-ga-yo-rok), 3 (Eum-sik-di-mi-bang), 7 (Jo-sun-mu-ssang-sin-sik-yo-ri-je-beop), 8 (Sang-ga-yo-rok $15^{\circ}C$), reducing sugar contents decreased rapidly after 1st mashing day and then increased slightly after 2nd mashing. The alcohol content increased as the fermentation proceeded, and most of the treatments produced 1/2 the amount of total alcohol content before the 2nd mashing day, followed by a slight increase until the end of fermentation (about 100 days from the 2nd mashing day). In the sensory evaluation, Samhaeju using methods 2, 4, 5, and 6 got high scores and had much reducing sugar contents than other treatments. Among the seven manufacturing processes, method 2 was relatively simple and got the highest score in the sensory evaluation. Therefore, method 2 would be suitable for industrialization and popularization of Korean traditional alcoholic beverage.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.823-830
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• 1995

Background: It has been found that Helper T cells in the peripheral blood are decreased in the cell mediated immunity in the pulmonary tuberculosis. But it has not been confirmed yet that only decrease in number of cells which has phenotype in the peripheral blood is defined to decrease in cell mediated immunity. The immunocytochemical study was performed to observe the change of the percentage of T-lymphocytes with their subsets and activated T cells in the peripheral blood of pulmonary tuberculosis and to know how many T cells would be activated, relative to resting cells in the peripheral blood. Methods: The peripheral blood obtained from twenty two patients and ten healthy controls were smeared on the gelatin coated slide glass prepared for of mononuclear cells. The double bridge technique of alkaline phosphatase-antialkaline phosphatase(APAAP) method was used. As the primary antibodies, $T_1$(anti-human T cell), $T_4$(anti-human helper/inducer T cells) and $T_8$(anti-human supressor/cytotoxic T cell) antibodies and interleukin-2 receptor (for early activated T cell), very late activation antigen (for activated cytotoxic T cell), T cell lineage specific activation antigen monoclonal actibodies were used. Results: 1) There were significantly decrease in the absolute number of $T_4$(+) cells but significantly increase of $T_8$(+) cells in the peripheral blood of pulmonary tuberculosis (p<0.05). 2) The percentage of $T_4$(+) cells showed significantly decrease in pulmonary tuberculosis but $T_8$(+)cells significantly increase(p<0.05). $T_4(+)/T_8(+)$ ratio showed significantly decrease in the peripheral blood of the pulmonary tuberculosis(p<0.05). 3) There were significantly increase in the absolute number of variable stages of activated T cells in the peripheral blood of the pulmonary tuberculosis(p<0.05). 4) The percentage of IL-2R, VLA-1, TLiSA were 6.45+1.56%, $7.64+1.34^*$, 10.45+1.16% in order which showed significantly increase in the peripheral blood of the pulmonary tuberculosis(p<0.05). Conclusion: We speculate that only a few percentage of T lymphocyte is activated in cell mediated immunity in pulmonary tuberculosis.