• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.75-82
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• 2005

To investigate the vegetation structure of the region from Dongchanggyo to Deogjusa in Woraksan National Park, 23 plots$(400m^2)$ set up with random sampling method were surveyed. Three groups Quercus mongolica-pinus densiflora community, Pinus densiflora-Quercus molica community, Mixed Broad-leaved community were classified by cluster analysis. Quercus mongolica, pinus densiflora, Quercus serrata and Fraxinus rhynchophyllai were found as a major woody plant species in Woraksan National Park region. In this area, Quercus mongolica and Pinus densiflora were dominated partially. In the future, the importance percentage of Pinus densiflora might be decreased, but those of Quercus mongolica, Quercus serrata and Fraxinus rhynchophyllai might be increased. High positive correlations were proved between Acer pic tum and Corylus heterophylla, Betula schimidtii; Acer pseudosieboldianum, Cornus controversa ; Stephanandra incisa and Symplocos sawafutagi, Lespedeza maximowixzii ; Symplocos sawafutagi and Fraxinus rhynchophyllai, Lespedeza maximowixzii; Fraxinus rhynchophyllai and Acer pseudosieboldianum, Lespedeza maximowixzii; Quercus variabilis and Fraxinus sieboldiana; Corylus heterophylla, and Rhododendron schlippenbachii; Acer pseudo sieboldianum and Lespedeza maximowixzii, and relatively high negative corrlations was proved between Quercus serrata and Betula schimidtii; Quercus mongolica and Quercus serrata; Corylus heterophylla and Lindera erythrocarpa. Species diversity(H') of investigated groups were ranged from $1.2393\~1.3674$ and it was relatively high compared to those of the ridge area of other national parks.

• Korean Journal of Environment and Ecology
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• v.23 no.4
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• pp.365-375
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• 2009

The growth characteristics of Pinus thunbergii windbreak forest around Goosipo Beach, Sangha-Myon, Gochang-Gun, Jeollabuk-Do have been investigated, and the results are summarized as follows. The soil in the site was light acid sand with pH 5.7, and the mean sodium concentration of soils was 1.42dS/m. The tree diameter, height, crown width, and shape ratio(Height/DBH) were better with tree density was coming lower. Especially, the rate of shape ratio under 60 was more in sites with low tree density. This demonstrated that the trees have grown more soundly when the tree density was lower. The direction of main winds and distribution ratio of tree inclination had a correlation. The inclined trees are seemed to be influenced by main winds when they were younger and by Typhoon partly. Eighty one vascular plant species were found in the sites, and more number of herbaceous plants (57 taxa) lived there than woody plants (24 taxa). And more plant species of dune were found at the site where dune have developed well. Some thinning works need at high tree density areas in order to ensure effects of coastal windbreak.

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.239-248
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• 2016

The habitat, age and spawning characteristics of the Korean eastern spined loach, Iksookimia yongdokensis, were investigated to obtain baseline data for its ecological characteristics in the Chuksancheon (stream), Yeongdeok-gun, Gyeongsangbuk-do, Korea. The difference between the habitats of juveniles (0+) and 1~4 year old loaches was that juveniles mainly inhabited sandy bottoms (substratum particle size $0.6{\pm}1.44\;cm$) with very slow velocities of water current ($2.4{\pm}2.09\;cm/sec$) and low depths ($29.2{\pm}7.57\;cm$), whereas 1~4 year old loaches inhabited pebble and cobble bottoms (substratum particle size 5.5~6.1 cm) with relatively fast velocities of water current (3.8~4.6 cm/sec) and deep depths (50~70 cm). The age groups for I. yongdokensis (female) estimated by the frequency distribution of total length in the spawning season (July) indicated that the 35~64 mm is 1-year old, the 65~94 mm group is 2-year old, the 95~119 mm is 3-year old, and the 120~145 mm is more than 4-year old. The sex ratio (♂/♀) was 0.69, and females were 10~30 mm larger than males. The lamina circularis at the base of the pectoral fins in males, a secondary sexual characteristic, formed at the 13th month after hatching. The spawning season according to the gonadosomatic index (GSI) was June to July with water temperatures of $20{\sim}25^{\circ}C$. The average number of eggs was $2,292{\pm}618$, with a diameter of $1.46{\pm}0.02\;mm$ for mature eggs.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.422-433
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• 2017

Unmanned Aerial Vehicle (UAV) has several advantages over conventional remote sensing techniques. They can acquire high-resolution images quickly and repeatedly. And with a comparatively lower flight altitude, they can obtain good quality images even in cloudy weather. In this paper, we developed for estimating garlic growth at field scale model in major cultivation regions. We used the $NDVI_{UAV}$ that reflects the crop conditions, and seven meteorological elements for 3 major cultivation regions from 2015 to 2017. For this study, UAV imagery was taken at Taean, Changnyeong, and Hapcheon regions nine times from early February to late June during the garlic growing season. Four plant growth parameters, plant height (P.H.), leaf number (L.N.), plant diameter (P.D.), and fresh weight (F.W.) were measured for twenty plants per plot for each field campaign. The multiple linear regression models were suggested by using backward elimination and stepwise selection in the extraction of independent variables. As a result, model of cold type explain 82.1%, 65.9%, 64.5%, and 61.7% of the P.H., F.W., L.N., P.D. with a root mean square error (RMSE) of 7.98 cm, 5.91 g, 1.05, and 3.43 cm. Especially, model of warm type explain 92.9%, 88.6%, 62.8%, 54.6% of the P.H., P.D., L.N., F.W. with a root mean square error (RMSE) of 16.41 cm, 9.08 cm, 1.12, 19.51 g. The spatial distribution map of garlic growth was in strong agreement with the field measurements in terms of field variation and relative numerical values when $NDVI_{UAV}$ was applied to multiple linear regression models. These results will also be useful for determining the UAV multi-spectral imagery necessary to estimate growth parameters of garlic.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.97-109
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• 1983

In this study, the effects on the soil compaction were investigated through the various testing method by changing the number of layers, the number of blows per layer and drop height. The results obtained in this study were summarized as follows. 1. Soil compaction was largely influenced by maximum grain size of soil in case of small testing mold diameter. 2. The compaction effect showed best in the well graded soil. In this test, compaction effect showed the best value in the soil which contained about 30~40% of particles finer than No. 200 sieves although it would vary according to the content of coarse grained soil. 3. Though the compaction method was changed at the level of compaction energy fixed, the effect of soil compaction showed little. 4. The increment of compaction energy increased the effect of soil compaction, but over a certain limit the soil compaction showed little on the effect. 5. In the method to increase the compaction energy for the purpose of the most reasonable effect, the soil compaction effect was differently shown according to the grain size distribution of the soil.

• Particle and aerosol research
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• v.14 no.2
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• pp.25-33
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• 2018

In this study, the concentration of fine indoor dust and the size distribution of fine indoor dust were analyzed by measuring the dust generated during the cleaning process of an indoor office. We measured $PM_{10}$, $PM_{2.5}$, and $PM_{1.0}$ and analyzed the size distributions of dust larger than $0.3{\mu}m$ in diameter during cleaning. The results showed that the concentration of $PM_{10}$ increased rapidly during cleaning, however $PM_{1.0}$ did not increase. Before cleaning with a broom, the fine dust concentration was about $50{\mu}g/m^3$, but increased to about $400{\mu}g/m^3$ as cleaning progressed. In the case of indoor cleaning with a vacuum cleaner, the concentration of $PM_{10}$ increased during the cleaning process and the increase of $PM_{2.5}$ was relatively small. $PM_{1.0}$ did not increase as in the case of cleaning the broom.

• Journal of Gastric Cancer
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• v.9 no.1
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• pp.14-17
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• 2009

The clinical significance of hepatic resection for gastric metastases is controversial, even though hepatic resection has been widely accepted as a modality for colorectal metastases. Very few patients with gastric hepatic metastases are good candidates for hepatic resection because of multiple bilateral metastases, extrahepatic disease, or advanced cancer progression, such as peritoneal dissemination or extensive lymph node metastases. Therefore, several authors have reported the clinical significance of hepatic resection for gastric metastases in a small number of patients. Considering the present results with previous reports. The number and distribution of tumors in hepatic metastases from gastric cancer was considered based on the present and previous reports. Several authors have reported significantly better survival in patients with metachronous metastasis than in those with synchronous disease. However, metachronous hepatic resection necessitates the dissection of adhesions between the pancreas, liver, and residual stomach to prepare for Pringle's maneuver. Patients with unilobar liver metastasis, and/or metastatic tumors <4 cm in diameter may be good candidates for hepatic resection. Synchronous metastasis is not a contraindication for hepatic resection. Most of the long-term survivors underwent anatomic hepatic resection with a sufficient resection margin. After hepatic resection, the most frequent site of recurrence was the remaining liver, which was associated with a high frequency of mortality within 2 years. A reasonable strategy for improvement in survival would be to prevent recurrence by means of adjuvant chemotherapy and careful follow-up studies.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.1
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• pp.45-50
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• 2009

By Laser Through-Silicon-Via process, debris and particles occur when you are forming. Therefore the research of TSV cleaning become important to remove those particles and debris. Both chemical cleaning method that uses a surfactant and physical cleaning method that uses a brush were studied with the via of $30{\mu}m$ diameter and $100{\mu}m$ depth on the 8 inch CMOS Image Sensor wafer. On the DI water and a surfactant in mixture ratio of 2:1, debris show $73{\mu}m^2$ per $0.054mm^2$. Cleaning is superior by lower mixture ratio of DI water and surfactant. In addition, It is less than 5% of debris distribution in the laser condition changed by Laser's frequency and its speed and cleaning had no effect. In the physical cleaning, there are no crack and damage when the system condition is set by $1000{\sim}3000rpm$ strip, $50{\sim}3000rpm$ rinsing, and $200{\sim}300rpm$ brushing Therefore, debris and particles can be removed by enforced chemical method and physical method.

• Resources Recycling
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• v.19 no.1
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• pp.33-39
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• 2010

The spheric sintered body with $6{\pm}2mm$ diameter was manufactured in a rotary kiln at $1125^{\circ}C$/15 min using green body formed by pelletizing the batch powder composing of coal bottom ash produced from power plant and dredged soil by 70:30, wt%. And the physical properties of sintered body (BD) were analyzed to confirm the possibility for applying to an absorbent to restore a contaminated soil. The sintered body had a giant pore above 100 ${\mu}m$ and a fine pore below 10 ${\mu}m$, and bulk density was 1.4. Also its specific surface area, porosity and void proportion were $12.0m^2/g$, 30.1% and 38.2% respectively. The crushed body (BD-C), produced by crushing a BD specimen into an irregular shape with a aspect ratio of about 2, was similar to BD specimen at bulk density and pore size distribution. But it had superior values of specific surface area, porosity and void proportion compared with BD specimen owing to a decreased apparent volume due to conversion of closed pore existed at interior of BD to open pore during a crushing process. The IEP of sintered body occurred at about pH=5, so the optimum pH condition of reacting aqueous solution could be known before bonding a microbe to the sintered body. Hence, the optimum void proportion and porosity of an absorbent can be obtained by appropriate mixing a BD with BD-C from the base data calculated in this study.

• Journal of Korea Water Resources Association
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• v.44 no.1
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• pp.65-72
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• 2011

Natural streams meander, forming pools at the outer part of bend and riffles at the crossing. Pools are deep at a lower flow velocity, and riffles are shallow at a higher flow velocity. Attentions are being paid to pool-riffle sequences in meandering streams because pool-riffle sequences tend to increase biodiversity of the stream ecosystem. This study investigates the characteristics of distribution of bed sediment particles in the upstream reach of the Gap Stream, which is a tributary of the Geum River in Korea. The upstream part of the Gap Stream, the study reach, is a gravel-bed stream, showing a pool and three riffles due to meandering. The reach also includes pools at the upstream and downstream parts of the weir. The characteristics of bed sediment particles sampled at the wetland and in the side channel are studied, revealing that the median particle diameter in the riffle is about four times larger than that in the pool. In addition, flow simulations are carried out for ordinary discharge and design flood, and such parameters important to sediment transport as velocity, shear stress, dimensionless shear stress (or Shields number), and dimensionless shear velocity are provided to see the mobility of sediment particles in the pool-riffle sequence.