• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.410-419
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• 2005

Community structure of evergreen broad-leaved forest of Mt. Yeogwi in Jin-do was investigated to secure sustainable conservation of evergreen broad-leaved forest. Twenty survey plots of $20m{\times}20m$ were established along the elevation from 200 m to 390 m above the sea level in the northwestern slope. The woody species were tallied at each plots. DBH distribution of the major evergreen broad-leaved trees was investigated to find out the spatial distribution. Cluster analysis was applied to a set of vegetation data, that is, importance value to classify the forest community. Species diversity, evenness and species correlation were analysed. Canonical correspondence analysis was also applied to vegetation data and soil environmental data. Cluster analysis showed that the forests of Mt. Yeogwi were classified into 2 community groups, such as Camellia japonica community group and Quercus acuta community group. C japonica community group was subdivided into C japonica- evergreen broad-leaved trees community, C. japonica-Neolitsea sericea community, and C. japonica-deciduous broad-leaved trees community. Q. acuta community group was subdivided into Q. acuta-C. japonica community, and Q. acuta community. C. japonica, Q. acuta, N. sericea, Machilus thunbergii and Illicium religiosum were dominant evergreen broad-leaved tree species, while Styrax japonica, Lindera erythrocarpa, Cornus kousa, Prunus sargentii, Albizzia julibrisin and Quercus acutissima were major deciduous tree species. Species diversity was greater in Q. acuta community group (0.8231 for Q. acuta-C. japonica community, and 0.8135 for Q. acuta community) than in C. japonica community group (0.7674 for C. japonica-evergreen broad-leaved trees community, 0.6164 for C. japonica-N. sericea community, and 0.7931 for C. japonica-deciduous broad-leaved trees community). DBH 2 cm~10 cm of major evergreen broad-leaved trees occupied 80% of all. C. japonica of less than DBH 5 cm tended to aggregate but distribute randomly or regularly with increasing DBH. Q. acuta distributed more aggregately than C. japonica and Machilus thunbergii for more than 15 cm of DBH. C. japonica correlated negatively with Q. acuta, I. religiosum and C. kousa, but positively with N. sericea. with significance at 1% level. Q. acuta correlated negatively with C. japonica, N. sericea and M. thunbergii but positively with l. religiosum. There were also negative correlation between N. sericea and C. kousa. CCA showed that forest communities were correlated with soil variables such as CEC, soil organic matter and soil pH. With increased soil organic matter and CEC, and decreased soil pH, C. japonica was dominant and forest community and Q. acuta and N. sericea tended to develop in the evergreen broad-leaved forest.

• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.1-8
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• 1976

One of the most common needle leaf species used in planting in Korea is korean pine (Pinus koraiensis S. et Z.), and jack pine (Pinus banksiana Lamb.) is one of the test species for suitability. The relation of nursery bed density of 2-1 korean pine and 1-1 jack pine was studied at the Kwang Nung Nursery, Central Branch Station of Forest Research Institute, and about 40km north of Seoul. Nursery bed density of 2-1 korean pine, which ranged from 36 to 324 trees per square meters and of 1-1 jack pine, which ranged from 25 to 169 trees per square meters, had a marked effect on caliper, height, dry weight and percent and amount of plantable stock. The soil physical and chemical properties is silt plus clay, 50.55 percent; organic matter, 2.09 percent; total nitrogen, 0.13 percent; available phosphorus, 253.25 ppm; exchangeable potash, 0.46 m.e/100g; and pH, 5.58. As the density of the nursery seedling stand of 2-1 korean pine increases, the average tree height increases (Fig. 1A), but in 1-1 jack pine density do not affect to increase or decrease the average tree height. As the density of nursery bed increases, the average stem caliper (at 2cm above ground line) and dry weight decrease (Fig. 1B), but the decreasing rate is more seriously in 1-1 jack pine than 2-1 korean pine (Fig.5). As increasing the density of nursery bed, the T/R ratio of trees of the test species increase. Also the dry weight of leaf, stem and root parts are decreasing in proportion to the increase of stand density, but the drop rate of jack pine is more rapid than korean pine (table. 1) The patent facts of difference of growth characteristics between 2-1 korean pine and 1-1 jack pine were studied. These facts should be used to select the scale of stand density at the nursery bed or the plantable site. Korean pine is demanded high density, on the other hand in jack pine low density are more suitable to manage the stand density. Stands of comparatively low density had the greatest percentage of high-quality stock, and the stands of high density had less than the high quality trees of low density. An important criterion of the best density is percent and number of high-quality trees produced per square meter of bed area. Stem caliper and stem height of seedling is used in most public nurseries to sort seedling into plantable grades. The stock grade standard has set at 4.5mm caliper and 16cm height of 2-1 korean pine as the minimum desired stem caliper and height. By the result studies, the plantable stock grade standards of 2-1 korean pine used at stem height 16cm and stem caliper 4.5mm from public nurseries should be reformed to stem height 18cm and stem caliper 4.0mm by the growth characteristics and the tree distribution of stem height and caliper of relation to density. For the 2-1 korean pine, best density should be about 160 to 200 trees per square meter according to soil fertility. For the 1-1 jack pine, the suitable standard of plantable stock should be at stem height 25cm and caliper 6mm (at 2cm above ground line) and best density was about 100 to 120 trees.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.349-355
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• 2018

This study was aimed at predicting the yield of paprika (Capsicum annuum L.) through analyzing the growth characteristics, yield pattern and greenhouse environment. In the greenhouse of the Gyeongnam area (667 m above sea level), the red paprika 'Cupra' and the yellow paprika 'Fiesta' were grown from July 5, 2016 to July 15, 2017. The planting density was $3.66plants/m^2$ and attracted 2 stems. During the cultivation period, the average external radiation of the glasshouse was $14.36MJ/m^2/day$ and the internal average temperature was controlled as $20.1^{\circ}C$. After 42 weeks of planting, the growth rate of 'Cupra' was 7.3 cm/week and that of 'Fiesta' was 6.9 cm/week. The first fruit setting of 'Cupra' appeared at 1.0th node and 'Fiesta' at 2.7th node. The first harvest of 'Fiesta' was 11 weeks after planting and 'Fiesta' was 14 weeks. Comparing the yield per 10 a until the end of the cultivation in July, 'Fiesta' was 19,307 kg, which was 2.4% higher than that of 'Cupra'. And the fruit weight ratio of over 200 g of 'Cupra' was 27.7% which was 7.7% higher than that of 'Fiesta'. The average required days to harvest after fruit setting of 'Cupra' was 72.6 days and 'Fiesta' was 63.8 days. According to the relationship between the average required days to harvest and the cumulative radiation (during from fruit setting to harvest), the more radiation increases the less required days to harvest increases after February. In terms of yield, 'Cupra' increased in yield as the cumulative radiation increased, while 'Fiesta' showed an irregular pattern. Cumulative radiation from fruit setting to harvest was negatively correlated with required days to harvest after February in both cultivars. But in relation to yield, there were difference between 'Cupra' and 'Fiesta'.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.312-318
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• 2018

We investigated the effect of postharvest treatments of calcium chloride, lysophosphatidyl ethanolamine (LPE) or 1-methylcyclopropene (1-MCP) on fruit quality during simulated marketing in Asian pear (Pyrus pyrifolia Nakai). 'Whangkeumbae' pear fruits were immersed in 0.25, 0.5 or 1.0% $CaCl_2$ solution with or without ultrasound (40kHz) at $25^{\circ}C$ for 3min followed by storage at $1^{\circ}C$ for 30 days simulated as abroad exportation. After simulated marketing at $25^{\circ}C$ and 80% relative humidity (RH) up for 10 days, quality parameters were evaluated. Results indicated that the ultrasound and $CaCl_2$ treatment had a synergic effect on keeping the green skin color which showed lower $a^*$ value. The combination treatment of ultrasound and 0.5% and 1.0% $CaCl_2$ significantly reduced internal browning disorders, although severe skin blemish disorder (20-23%) occurred in 1.0% $CaCl_2$ treatment. 'Wonhwang' pears were immersed in 1,000ppm LPE for 3 minutes or were fumigated in 1,000 ppb 1-MCP for 12 hours, respectively. The results of the fruit quality survey during the 21 days of distribution period are as follows. The 1-MCP treatment was maintained at a constant flesh firmness of 33N or higher during the distribution period. The LPE treated fruits had a lower physiological disorder index than the untreated group, but showed a relatively higher value than the 1-MCP treated group. In the case of 1-MCP treatment, the fruit respiration rate was significantly lower than of untreated control ($6.0mL{\cdot}kg^{-1}{\cdot}hr^{-1}$) during the simulaed marketing period. Consequently, it was expected that the postharvest treatments of 0.5% calcium chloride in pararell with ultrasound and 1-MCP fumigation can help to maintain Asian pear quality during distribution period.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.673-682
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• 2001

The use of resin composites has continued to increase over the last several years. In spite of their growing popularity, composites continue to exhibit a number of undesirable characteristics. One of the major deficiencies of composite restorative resins is their inadequate resistance to wear. Of the multitude of factors that have been associated with wear, subsurface degradation within the restoration is considered to be one. The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. This solution with a high concentration of hydroxyl ions is a convenient medium for accelerated degradation of silane coupling and filler particles. The brands studies were Definite($Degussa-H\ddot{u}ls$ AG, Germany), Prodigy(Kerr, USA), Pyramid(Bisco, USA) and Synergy(Coltene, Swiss). Preweighed discs of each brand were exposed to 0.1N NaOH solution at $60^{\circ}C$. After 14 days they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters : (a) mass loss(%)-determined from pre-and post-exposed specimen weights : (b) Si loss(ppm)-obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation $depth({\mu}m)$-measured microscopically (SEM) from polished circular sections of exposed specimens. The results were follows: 1. Mass loss of Synergy was $1.24{\pm}0.002%$, it was the highest, there was no significant difference among the materials. 2. The degree of degradation layer depth of Synergy was $107.83{\pm}2.52{\mu}m$, it was the highest, there was no significant difference among any other materials than Synergy. 3. There was no difference among the four materials in Si loss. 4. The correlation coefficient between mass loss and degradation depth was relatively high(r=0.06, p<0.05). 5. There was no coefficient correlation between Si loss and mass loss, the degree of degradation layer depth and Si loss. 6. When observed with SEM, destruction of bonding is observed between resin matrix and filler.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.685-695
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• 2004

The aim of this study was to evaluate the resistance to degradation and to compare the wear resistance characteristics of four composite resins in an alkaline solution. The resistance to degradation was evaluated on the basis of mass loss(%), degradation depth(${\mu}m$), Si loss(ppm) and wear depth. The brands studied were Heliomolar flow, Filtek supreme, Point4, Tetric flow. The results were as follows: 1. The sequence of the mass loss was in descending order by Heliomolar flow, Filtek supreme, Point4, Tetric flow. There was significant differences among the materials except Heliomolar flow and Filtek supreme. 2. The sequence of the degree of degradation layer depth was in descending order by Filtek supreme, Heliomolar flow, Tetric flow, Point4. There were significant differences among the materials except Heliomolar flow and Tetric flow. 3. The sequence of Si loss was in descending order by Filtek supreme, Heliomolar flow, Point4, Tetric flow. There were significant differences among the materials except Point 4 and Tetric flow. 4. The sequence of maximum wear depth was in descending order by Heliomolar flow, Point4, Fillet supreme, Tetric flow and there was increasing wear depth on soaking in 0.1N NaOH solution. 5. When observed with SEM, destruction of bonding between matrix and filler was observed and when observed with CLSM, the depth of degradation layer of specimen surface was observed. There results indicate that wear and hydrolytic degradation could be considered to be evaluation factors of composite resins.

• Journal of Aquaculture
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• v.13 no.2
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• pp.169-174
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• 2000

Reproductive cycle of U. unicinctus was studied from September 1998 to August 1999, using gonadosomatic index (CSI) as an indicator. In November, the CSI values were maximum for male (6.2) and female (7.0), respectively; the values were lowest for them (1.0 and 0.5) during the successive february. Subsequently, they rapidly increased and attained peak by March-April. The values decreased again in both sexes and remained unchanged until August. The index increased in October to attain the peak by November. The CSI values clearly indicated that there are two spawning events in a year, namely the first one during April-May and the second one in December. Reproductive cycle was classified into the following successive stages: in female, multipication (January~February, June ~Setember), maturation (March~April, November), spent (May and December), degeneration and resting (June and January), and in male, multiplication January ~ february, June ~September), maturation (March~April, October~November), spent (May and December) and degeneration and resting (January and June). Histological observations revealed that oocytes in the ovary matured simultaneously in November and March. At the same time, the envelopes of matured testis became thinner than those in the early stage.

• Food Science and Preservation
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• v.20 no.2
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• pp.182-190
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• 2013

This study investigated the quality characteristics between spring cultivars of Kimchi cabbage(Brassica rapa L. ssp. pekinesis). We measured the weight, length, width, formation index, midrib thickness and moisture contents of fresh Kimchi cabbage for characteristics of growth. And we analyzed the free sugar, amino acid, organic acid, mineral, pectin and cellulose contents of fresh Kimchi cabbage. The hardness and firmness were measured for texture of fresh Kimchi cabbage. The weight of 'K-power' cultivar was the highest than other cultivars. The 'Jeongsang' cultivars was the thinnest midrib thickness in cultivars, but it was not significantly different. The free sugar levels of spring cultivars was the highest in 'Chunkwang'. Malic acid content of 'Jeongsang' was significantly different among spring cultivars. Also amino acid content of 'K-power' and 'Chunkwang' were significantly different among spring cultivars Mineral content in 'K-power' and 'Bomaknorang' were greater than that of other cultivars. Especially Na, Ca and Mg contents of 'K-power' and 'Bomaknorang' were higher four times than that of other cultivars. Pectin content of 'Jeongsang' was higher than that of other cultivars, but it was not significantly different. Hardness and Firmness were not significantly different among spring cultivars.

• Journal of Life Science
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• v.16 no.4
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• pp.683-690
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• 2006

The chemical compositions of amino acids, minerals, betaine, and polyphenolic compounds from Salicornia herbacea (Hamcho) according to harvest periods were analyzed. Changes of chemical characteristics in water and ethanol extracts from Hamcho were evaluated for titratable acidity, pH, soluble solid, and Hunter's color values. The antioxidative activity of water extract from Hamcho was also determined by DPPH $({\alpha},{\alpha}'-diphenyl-{\beta}-picrylhydrazyl)$ scavenging radical activity. Total polyphenolic compounds of Hamcho were shown the highest in August harvested by 201.6 ppm. The betaine of Hamcho water-extract was identified by high performance liquid chromatography (HPLC), which content was 0.248%, 0.269% and 0.204% in June, August, and October, respectively. Major compositional amino acids (mg%) were glutamic acid (582: 519: 664), proline (552: 471: 322), phenylalanine (480: 431: 424), aspartic acid (322: 297: 330), and arginine (282: 321: 483) in June, August, and October, respectively, and major free amino acids (mg%) were proline (9.7: 3.4), asparagine (6.7: 1.4), hydroxyproline (6.4: 2.8), valine (3.9: 2.5), arginine (1.7: 3.0) in June and August, respectively. Mineral contents (mg%) were Na (5,695: 7,536: 5,529), K (1,640: 963: 931), Mg (359: 428: 348), Ca (221: 234: 251), and P (207: 189: 259) in June, August, and October, respectively. Especially, K was high in June, Na and Mg were high in August, and Ca and P were high in October, respectively. DPPH scavenging radical activity was shown in the following order; 0.05% butylated hydroxytoluene (BHT)> August> June> October harvested Hamcho. The chemical components of polyphenolic compounds, betaine, amino acids and minerals were changed by harvest periods according to the growing season, and the highest concentrations of polyphenolic compounds and betaine of Hamcho were shown in August harvested.

• Korean Journal of Environmental Agriculture
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• v.6 no.2
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• pp.39-45
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• 1987

A water culture experiment was conducted to investigate the effect of As content in a culture solution on the water status and growth of rice plants. Rice (Oryza sativa L. Line. Iri 316) seeds were germinated in bentonite and cultivated there for 30 days. Rice seedlings were transplanted into 3.5l pots containing the culture solution on May 1, 1985 and allowed to grow without As treatment for one month. Afterwards, they were grown in a culture solution maintaining the final concentration of As, 0, 1, 5, 10 and 15mg/1 renewing in the solution dissolved sodium arsenate at intervals of 3 to 7 days. Plants were cultivated in the green house during the growing period and harvested 60 days after As treatment. The results obtained were as follows: Transpiration of rice plants was decreased with the increase of the As level in the culture solution. Stomatal diffusive resistance and leaf temperature increased with increase of As levels though the humidity and the air flow rate in leaf decreased. Air flow rate, transpiration and stomatal diffusive resistance showed a highly significant correlation with As contents in shoots and roots of rice plants: Espally The air flow rate and transpiration revealed a significantly higher correlation with As contents in the root than that in the shoot, but diffusive resistance showed adverse tendency. High levels of As in the culture solution depressed plant height, no. of tillers, leaf width and dry weight of plant remarkably. Typical symptoms of As toxicity were root discoloration, and necrosis of leaf tips and margins, and leaf rolling during the sunny daytime were also another symptoms.