• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.93-100
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• 2004

The content of nutrients such as organic carbon, nitrogen, phosphorus and potassium accumulated on soil layers in Quercus mongolica forest of Mt. Songnisan National Park located at central part of Korea was measured, and then the decomposition constants and decay times of the nutrients were also calculated by the negative coefficience model(O1son,1963). The quantities of organic carton of L-layer, F-layer, H-layer and $A_1$-layer of the forest stand were 231.25 g $m^{-2}$, 291.50 g $m^{-2}$,166.91 g$m^{-2}$ and 174.51 g $m^{-2}$, respectively. The content of organic carbon and nitrogen contained in L-layer and F-layer showed large quantity than those of other layers. The large amount of phosphorus and potassium was observed at the B-layer and $A_1$-layer. On the other hand, the decomposition constants(k) of soil organic matter were as follows : organic carbon (k = 0.3657), nitrogen (k = 0.3319), phosphorus (k = 0.2050), and potassium (k = 0.0934) and the decay times needed to 99% decomposition of nutrients in soil organic matter were as follows: that is, organic carton, nitrogen, phosphorus and potassium was 13.94 years, 15.18 years, 24.79 years, and 55.11 years, respectively. By the application of Turbo Pascal Program on the inflowed and outflowed nutrients to the forest stand,87.67% (714.84 g $m^{-2}$) of organic carbon inflowed was decomposed and 81.62% (1,594.62 g $m^{-2}$) of organic carbon accumulated was decomposed. And 84.98% of nitrogen inflowed was decomposed and 70.26% of nitrogen accumulated was also decayed.50.00% of phosphorus input and 40.31% of potassium input were decomposed, and 38.40% of phosphoyus and 33.03% of potassium accumulated were also decayed, respectively. Therefore, it is suggested that Quercus mongolica forest surveyed in the present study is maintaining in steady state because input and output amounts of nutrients is shown a similar pattern.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.1-6
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• 1994

Some physicochemical properties of sugary rices were comparatively analyzed with the original cultivars, using Hwachung su-1, su-2, and Nampung su lines bred in Seoul Nat'l Univ., and EM 5 bred in Kyushu Univ. Sugary rice grains were smaller in width and thickness, and the relative dry weight of 1000 grains of sugary rices ranged from 49% to 72%, compared to normal ones. No distinct starch granules were found in endosperm of sugary rices exposured by SEM, with structural variations between Hwachung su-1 and su-2 lines. Sugary rices showed the significant increases in sucrose, glucose and fructose content, especially much higher in sucrose content showing 5.84-8.79%, in comparison with the normal ones, 1.11∼2.65%. However, sucrose and total sugar content varied within sugary lines carrying the same sugary gene, and were significantly lower in Hwachung su-2. Sugary rices, except Hwachung su-1, showed the same or lower ADV and harder gel characteristics, compared to normal ones. Protein and lipid content were much higher in sugary rices, due to the increased relative proportion of aleurone layer in brown rice caused by thicker aleurone layer than in normal rices and the reduction of endosperm part. However, there were no remarkable changes in amino acid and fatty acid compositions.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.15 no.2
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• pp.49-54
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• 2009

The effects of filling temperatures of broth and degassing method on the residual oxygen content and gas composition in the pouch and physical strength of packaging material for Samgyetang depending on the contamination of broth on the sealing layer and sterilization process were investigated. The residual oxygen content in the broth and the oxygen proportion in the headspace of package were decreased with the increase of broth temperature at filling into the pouch from 50 to 100. When the products were packaged as air-contained (Air), manually squeezed the upper side of package out to minimize the headspace (Degas) and flushed with nitrogen gas ($N_2$-Flushing) while maintaining the broth temperatures of Samgyetang at 50 or 85. The residual oxygen content and oxygen proportion were increased in the order of $N_2$-Flushing

• Journal of Conservation Science
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• v.36 no.5
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• pp.393-404
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• 2020

We observed changes in the properties of the glaze layer according to the content of iron oxide and inferred the composition, content, and environment of the materials used in the past during the production process of black ware. First, experiments were conducted using different ratios of iron oxide, feldspar, calcite, and ash at different temperatures and firing environments; the characteristics of glaze were classified into five groups in the oxidation environment. Different properties were identified in the reducing environment above 1200℃. The crystal identified in the experiment was similar to the glaze characteristics in the excavated black ware. The crystal phase appeared in four groups: band shape, circular, arborescent phase, and needle crystal, depending on the change in the content of iron oxide. However, the difference in crystals did not appear significantly at high temperatures. In addition, crystals of glaze were divided into two groups depending on the component ratio. The presence or absence of feldspar is thought to affect crystallinity and amorphous iron oxide and the changes in the glaze layer changed substantially depending on the amount of iron oxide. In particular, it was confirmed that the aspects of iron oxide in the oxidation and reduction environments were different and, therefore, crystallization due to the firing environment also affected the optical characteristics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.125-132
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• 1983

Dielectric properties of sardine-starch paste with moisture content of 4 to $13\%$ were investigated as functions of moisture and frequency. And the effects of the levels of fat and starch of the mixtures upon dielectric permittivity, critical moisture, were also mentioned. In addition, a theoretical prediction of frequency dependence of dielectric constant which was computed by the lumped circuit of two layer condenser model was evaluated. For the preparation of sardine-starch paste, comminuted sardine meat was washed thoroughly several times in chilled water by soaking and decanting, and finally centrifuged. This procedure was extended longer to provide a low fat sample. The centrifuged meat was mixed with adequate amounts of starch and salt, and ground for 25 minutes in a stone mortar, moulded in the form of disk with 7cm diameter and 1.2cm thickness and then freeze dried. Dried meat disks were cut off for the size of 5.5cm diameter and 1.0cm thickness and their moisture contents were controlled in humidified desiccators with saturated solutions. Dielectric constants of sardine-starch paste tended to decrease frequency was increased showing a critical charge at the moisture called critical moisture content. In case of the sample with $20\%$ starch and $2\%$ salt an average complex permittivity($\epsilon^{\ast}$) at 7 to $8\%$ morsture as the critical moisture content was presented; $\epsilon^{\ast}$=3.37+j 0.39 at 0.1 MHz, $\epsilon^{\ast}$=2.54+j 0.19 at 15 MHz, and $\epsilon^{\ast}$=2.15+j 0.08 at 1.8 GHz, respectively. The theoretically obtained complex permittivity values from the two layer condoner model were in close agreement with these actual measurements under the same conditions, that appeared as $\epsilon^{\ast}$=2.53+i 0.09 at 0.1 MHz and $\epsilon^{\ast}$=2.28+j 0.06 at 15 MHz, respectively. The fast level of the mixture also revealed an influence on dielectric property that defatted neat with $1.0\%$ fat showed a higher hc and $\epsilon^{\ast}$ value than the meat with $4.8\%$ fat. Complex permittivity being related to the moisture level remained nearly unchanged or slightly changed at the moisture range of 4 to $8\%$ but was dispersed widely at higher moisture contents.

• Journal of the Korean Institute of Landscape Architecture
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• v.20 no.1
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• pp.80-94
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• 1992

To inspect the changing of the forest soil and plants community structrure by air plooutand & acid rain during from September to November in 1990, the smapling sites were selected in the Piwon, Namsan and Kwangnung forest. In sites, plots were set up in Q. aliena forest at Piwon, Quercus mongolica and Pinus densiflora forest at Namsan and Q. mongolica and Pinus densiflora forest at Kwangnung. To obtain the individual number of trees, number of species, importance values and species diversity, using the Curtis & McIntosh methods. The results are following that; 1) In Pinus densiflora community, it was almost dominated by Q. spp. in the canopy layer and P. densiflora and Carpinus laxiflora through the subtree to shrub layer at Kwangnung. It wassaid that C. laxiflora is the climax species in moddle temperature zone. On the contrary, in Namsan forest, there is no appearance thesamplings of P. densiflora & C. laxiflora, but Styrax japonica and Stephanandra incisa that are acid-tolerance species are dominant ones. On the other hand, in Q. spp. community, Q. spp. and C. laxiflora are dominant ones. On the other hand, in Q. spp. community, Q. spp. and C. laxiflora are dominant species through all layer, and in addition C. cordata somewhat appear at Kwangnung. But at Namsan and Piwon forest, Q. mongolica & Q. aliena that were dominant species in canopy layer disappeared in the subtreeand shrub layer, and C. laxiflora and Corunus cordata absolutely disappeared. It were similarly dominated by Robinia pseudo-acacia, Styrax japonica, Sorbus alnifolia, Acer pseudo-sieboldianum, Rhododendrn mucronulatum and so on at Namsn and Piwon forest. In the light of these facts, it found out that disclimax was similar between Namsan and Piwon forest. 2) Species diversity and maximum species diversity were decreased in Kwangnumg, Namsan, Piwon in order. It was xpected that vegetational community was affected by environmental pollutant. 3) As the vegetational community structure analyses, using DCA technique among the ordination, ecological successional series are stopped to Q. spp. from P. densiflora at Namsan and Piwon, but that of Kwangnung is on the way that P. densiflora, Q. alena, C. laxiflora. It was obvi ously different from Namsan and Piwon. 4) In Q. spp. & P. densiflora community, the number of woody plants inNamsan & Piwon is much less than that of Kwangnung through all Layer. Especially, Piwon shown very severe difference. Through all community, the number of individuals of Piwon and Namsan are less than that of Kwangnung. Specially, that of the shrub layer is obvious. 5) In the growth rate of trees, it found out that all sites showed the growth decline phenomena. Especially, since in 1975, there have been the micro disclimax phenomena in Q. community of Kwangnung. 6) In the Q. community, soil acidity of Namsan & Piwon measured 4.57, 4.40 respectively. It was very strong acidity and far lower than that of Kwangnung. Also the content amount of Mg++ in Namsan & Piwon forest were still lower than Kwangnung.

• Journal of Wetlands Research
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• v.22 no.4
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• pp.328-336
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• 2020

In this study, the soil characteristics of peat layer in Korea were analysed to predict new peat distribution areas in Taean, Chungcheongnam-do. The soil characteristics of peat distribution areas in Taean were compared with those in other areas in Korea. In Korea, peat researches were conducted in various regions, such as Taean in Chungcheongnam-do, Pyeongtaek in Gyeonggi Province, Gangneung in Gangwon-do, Ulsan, Iksan in Jeollabuk-do and Jangheung in Jeollanam-do. We summarized a) topographic distribution, b) deposition type, c) soil drainage classes, and d) soil suborder of previously studied area to determine criteria for prediction of peat distribution area. Through a case study, the type of peat layer distribution area in Taean were divided into two; (1) a) valley, b) co-alluvium, c) somewhat poorly drained, d) aqualfs and (2) a) marine plain, b) alluvium, c) very poorly drained, d) aquepts. A field survey was conducted to confirm the distribution of the actual peat layer. All peat layer were located within 10-km from the coastal line which is similar to previous studies, and the peat layer was characterized with pH 5, humic acid content of less than 15% and dark brown color. The new peat layer in Taean was deeper, thicker and less humificated than other studied areas.

• Journal of the Korean Electrochemical Society
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• v.25 no.4
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• pp.174-183
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• 2022

Polymer electrolyte fuel cells and water electrolysis are attracting attention in terms of high energy density and high purity hydrogen production. The catalyst layer for the polymer electrolyte fuel cell and water electrolysis is a porous electrode composed of a precious metal-based electrocatalyst and an ionomer binder. Among them, the ionomer binder plays an important role in the formation of a three-dimensional network for ion conduction in the catalyst layer and the formation of pores for the movement of materials required or generated for the electrode reaction. In terms of the use of commercial perfluorinated ionomers, the content of the ionomer, the physical properties of the ionomer, and the type of the dispersing solvent system greatly determine the performance and durability of the catalyst layer. Until now, many studies have been reported on the method of using an ionomer for the catalyst layer for polymer electrolyte fuel cells. This review summarizes the research results on the use of ionomer binders in the fuel cell aspect reported so far, and aims to provide useful information for the research on the ionomer binder for the catalyst layer, which is one of the key elements of polymer electrolyte water electrolysis to accelerate the hydrogen economy era.

• Journal of Ecology and Environment
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• v.35 no.1
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• pp.1-7
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• 2012

To calculate and predict soil carbon budget and cycle, it is important to understand the complex interrelationships involved in soil respiration rate (Rs). We attempted to reveal relationships between Rs and key environmental factors, such as soil temperature, using a laboratory incubation method. Soil samples were collected from mature deciduous (MD), mature coniferous (MC), immature deciduous (ID), and immature coniferous (IC) forests. Prior to measure, soils were pre-incubated for 3 days at $25^{\circ}C$ and 60% of maximum water holding capacity (WHC). Samples of gasses were collected with 0, 2, and 4 h interval after the beginning of the measurement at soil temperatures of 5, 15, 25, and $35^{\circ}C$ (at 60% WHC). Air samples were collected using a syringe attached to the cap of closed bottles that contained the soil samples. The $CO_2$ concentration of each gas sample was measured by gas chromatography. Rs was strongly correlated with soil temperature (r, 0.93 to 0.96; P < 0.001). For MD, MC, ID, and IC soils taken from 0-5 cm below the surface, exponential functions explained 90%, 82%, 92%, and 86% of the respective data plots. The temperature and Rs data for soil taken from 5-10 cm beneath the surface at MD, MC, ID, and IC sites also closely fit exponential functions, with 83%, 95%, 87%, and 89% of the data points, respectively, fitting an exponential curve. The soil organic content in mature forests was significantly higher than in soils from immature forests (P < 0.001 at 0-5 cm and P < 0.005 at 5-10 cm) and surface layer (P = 0.04 at 0-5 cm and P = 0.12). High soil organic matter content is clearly associated with high Rs, especially in the surface layer. We determined that the incubation method used in this study have the possibility for comprehending complex characteristic of Rs.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.82-88
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• 2007

Two experiments were conducted to see the effects of lacquer meal (Rhus verniciflua) on layer performance. In Exp. 1, seventy-two Hy-Line brown layers, 46 wk of age were fed 0, 1.5% and 3.0% lacquer added diets for 6 weeks. Diets contained 2,650 kcal/kg ME and 16.50% CP. In Exp. 2, high-energy diets were fed to 72 Hy-line brown layers of 46 wk age for 6 wk. The diets were: control (3,000 kcal/kg ME and 16.50% CP); T1 and T2 contained 1.5 and 3.0% lacquer respectively, in addition to high energy levels. Each treatment had four replicates with 6 birds each in both the experiments. During Exp.1, there was no effect on average daily feed intake, egg production and feed efficiency, however, egg weight was linearly (p=0.0128) decreased with the addition of lacquer in diets. The egg quality parameters measured at bi-weekly intervals did not reveal any particular trend. In Exp 2., high-energy diets have decreased the feed intake and egg production in all groups. However, feeding lacquer at 1.5% increased the egg production by 9% than control. The yolk fat content was increased due to treatments showing quadratic trend (p=0.0683). The liver fat content was decreased by 40-43% than control in lacquer added diets. Except palmitic, oleic and arachidonic acids, some yolk fatty acids showed a linear decreasing trend in lacquer diets. The serum triglycerides and total cholesterol levels were not influenced with lacquer in the diets; however, the serum glucose level was linearly decreased with the addition of lacquer. In conclusion, lacquer meal supplementation significantly affected the performance of layers fed high-energy diets.