• Applied Microscopy
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• v.23 no.2
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• pp.27-40
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• 1993

This study was taken to examine the light microscopic and ultrastructural changes of gill and kidney of female tilapia{Oreochromis niloticus) adapted in 0%o, 10%o, 20%o, and 30%o salt concentrations, respectively, by light, scanning and transmission electron microscope. The results obtained in these experiments were summarized as follows: Gill chloride cell hyperplasia, gill lamellar epithelial separation, kidney glomerular shrinkage, blood congestion in kidneys and deposition of hyalin droplets in kidney glomeruli, tubules were the histological alterations in Oreochromis niloticus. Incidence and severity of gill chloride cell hyperplasia rapidly increased together with increase of salinity, and the number of chloride cells in gill lamellae rapidly increased in response to high external NaCl concentrations. The ultrastructure by scanning electron microscope(SEM) indicated that the gill secondary lamella of tilapia(Oreochromis niloticus) exposed to seawater, were characterized by rough convoluted surfaces during the adaptation. Transmission electron microscopy(TEM) indicated that mitochondria in chloride cells exposed to seawater, were both large and elongate and contained well-developed cristae. TEM also showed the increased chloride cells exposed to seawater. The presence of two mitochondria-rich cell types is discussed with regard to their possible role in the hypoosmoregulatory changes which occur during seawater-adaptation. Most Oreochromis niloticus adapted in seawater had an occasional glomerulus completely filling Bowman's capsule in kidney, and glomerular shrinkage was occurred higher in kidney tissues of individuals living in 10%o, 20%o, 30%o of seawater than in those living in 0%o of freshwater, and blood congestion was occurred severer in kidney tissues of individuals living 20%o, 30%o of seawater than in those living in 10%o of seawater. There were decreases in the glomerular area and the nuclear area in the main segments of the nephron, and that the nuclear areas of the nephron cells in seawater-adapted tilapia were of smaller size than those from freshwater-adapted fish. Our findings demonstrated that Oreochromis niloticus tolerated moderately saline environment and the increased body weight living in 30%o was relatively higher than that living in 10%o in spite of histopathological changes.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2001.06a
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• pp.141-142
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• 2001

남서부 경기육괴의 편마암류로부터 분리된 저어콘(zircon) 입자를 대상으로, 이온현미분석기(ion microprobe)를 사용한 U-Pb 연대를 구하였다. 그 결과는 후기 원생대(약 820 Ma) 뿐만 아니라 오르도비스기에 상당한 화성활동이 한반도에 있었음을 지시한다. 우리 나라 후기 원생대의 화성-변성 활동에 대해 알려져 있는 바는 극히 제한적이어서 후속연구가 필수적이며, 이러한 연구는 한반도의 지체구조적 변천사를 로디니아 초대륙(Rodinia supercontinent)의 생성-분리와 관련해 재조명할 수 있는 기회를 제공할 것이다. 또한 오르도비스기의 화성작용은 그동안 논란이 되어 왔던 소위 “칼레도니아(Caledonian)” 변동 (cf. 조문섭, 2000)에 대한 또 다른 증거를 제공해준다. 저어콘의 연대측정은 서호주의 커튼공업대학교에 설치되어 있는 SHRIMP-II(Sensitive High-Resolution Ion Microprobe-II; 고감도-고분해능 이온현미분석기)를 사용하였으며, 시료 준비 및 분석방법은 기존에 보고된 바와 같다 (e.g., Kinny et al., 1999). 분석된 3개의 암석 시료(1006-5, 8, 9)는 경기육괴의 남서부에 위치한 홍성 지역의 정편마암들이다. 1006-8 시료는 Turek and Kim (1996)이 전통적인 방법을 사용해 687$\pm$5 Ma의 U-Pb 저어콘 연대를 보고한 바 있는 화강암질 편마암 (시료번호, KJ43)에 해당된다. 두 개의 다른 시료는 1006-8 주변에서 산출하는 전형적인 경기육괴의 편마암류로서 화강암질 정편마암이다. 이들 시료로부터 분리된 저어콘 입자들은 대부분 화성기원의 누대구조와 자형의 결정형태를 보여준다. 과성장띠(overgrouth rims)는 1006-5 시료에서 흔하게, 그리고 1006-9 시료에서 매우 드물게 관찰된다. 음극선발광(cathodoluminescence) 영상의 해석을 통해 저어콘 결정의 성장사를 유추하였으며, 이를 바탕으로 이온현미분석 점(spot)을 정하였다. U-Pb-Th 자료는 퍼스(Perth) 저어콘 스탠다드 (CZ3, 564 Ma, $^{206}$Pb/$^{238}$U=0.0914)를 사용하였다. 아래에 기술하는 연대는 모두 $^{206}$Pb/$^{238}$U 연대에 해당된다. 두 개의 화강암질 편마암 시료로부터 구한 U-Pb 저어콘 연대는 각각 812 $\pm$ 14 Ma(1006-8)와 822 $\pm$ 17 Ma(1006-9)로 분석오차 내에서 서로 일치한다. 이 결과는 춘천 및 전곡 지역의 석류석 각섬암에서 보고된 Sm-Nd 전암연대(852 $\pm$ 24 Ma 및 824 $\pm$ 143 Ma; Lee and Cho, 1995; Ree et al., 1996)와 잘 부합한다. 따라서 후기 원생대 기간 중 화성활동이 한반도에서 광범위하게 일어났음을 시사한다. 한편, 1006-9 시료에서는 예외적으로 한 개의 저어콘 입자 주변부(rim)에서 매우 얇은 과성장띠가 관찰되었으며, 두 개의 점 분석으로부터 구한 U-Pb 저어콘 연대는 약 235 Ma이다. 이 띠는 또한 변성기원의 저어콘에서 흔히 관찰되는 작은 W (<0.05) 비를 보인다. 1006-5 시료는 위 두 시료로부터 수 km 떨어진 지점에서 채집하였으나, 저어콘 연대는 상이한 기록을 보여준다. 즉 매우 작은 Th/U (<0.01) 값을 갖는 저어콘의 주변부에서 223 $\pm$ 5 Ma의 연대가 잘 정의되며, 이는 1006-9 시료에서 관찰된 결과와 함께 트라이아스기의 고온변성작용이 백립암상에 가까운, 매우 높은 온도에 달하였음을 지시한다. 한편 저어콘의 중심부는 335-473 Ma의 비교적 넓은 연대 분포를 보인다. 이는 저어콘이 실제 성장한 연대를 지시하기보다는 트라이아스기의 변성작용에 따른 납손실(Pb loss) 그리고 누대 규모보다 더 큰 빔 크기(beam size, 약 30 $\mu\textrm{m}$)의 영향일 것으로 해석된다. 또한 저어콘이 다양한 외래물질로부터 기원했다는 증거가 관찰되지 않으므로, 이 정편마암의 모암은 오르도비스기(약 430-470 Ma)에 관입하였을 것으로 생각된다. 따라서 그동안 논란이 되어 왔던 소위 “칼레도니아” 변동이 한반도 내에 실존하였을 가능성을 시사한다. 이상의 결과를 종합하여 볼 때, 경기육괴의 변성암류는 후기 원생대 이후 다양한 저어콘의 성장사를 기록하고 있음을 알 수 있다: 즉 (1) 후기원생대(약 820 Ma)의 화성작용; (2) 오르도비스기(약 450 Ma)의 화성작용: 그리고 (3) 트라이아스기 (약 223 Ma)의 부분용융을 수반한 고온 변성작용으로 대표된다. 이러한 지질연대는, 옥천변성대에서 얻어진 756 Ma의 저어콘 연대(Lee et al., 1998)와 더불어, 친링-다비-수루(Qinling-Dabie-Sulu) 대륙 충돌대와 양쯔 지괴에서 보고된 지질연대 결과와 잘 부합한다. 따라서 지구연대학적으로 경기육괴가 북중국보다는 대륙충돌대를 포함하는 남중국지괴에 속할 것으로 결론지을 수 있다.

• Geophysics and Geophysical Exploration
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• v.11 no.3
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• pp.250-262
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• 2008

In order to assess the feasibility of the dipole-dipole electric method to the investigation of metallic ore deposit, both field data simulation and inversion are carried out for several simplified ore deposit models. Our interest is in a vein-type model, because most of the ore deposits (more than 70%) exist in a vein type in Korea. Based on the fact that the width of the vein-type ore deposits ranges from tens of centimeters to 2m, we change the width and the material property of the vein, and we use 40m-electrode spacing for our test. For the vein-type model with too small width, the low resistivity zone is not detected, even though the resistivity of the vein amounts to 1/300 of that of the surrounding rock. Considering a wide electrode interval and cell size used in the inversion, it is natural that the size of the low resistivity zone is overestimated. We also perform field data simulation and inversion for a vein-type model with surrounding hydrothermal alteration zones, which is a typical structure in an epithermal ore deposits. In the model, the material properties are assumed on the basis of resistivity values directly observed in a mine originated from an epithermal ore deposits. From this simulation, we can also note that the high resistivity value of the vein does not affect the results when the width of the vein is narrow. This indicates that our main target should be surrounding hydrothermal alteration zones rather than veins in field survey. From these results, we can summarize that when the vein is placed at the deep part and the difference of resistivity values between the vein and the surrounding rock is not large enough, we cannot detect low resistivity zone and interpret the subsurface structures incorrectly using the electric method performed at the surface. Although this work is a little simple, it can be used as references for field survey design and field data Interpretation. If we perform field data simulation and inversion for a number of models and provide some references, they will be helpful in real field survey and interpretation.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.189-198
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• 2007

The reproductive cycle, egg capsules in the egg-mass, first sexual maturity, and sex ratio of the bladder moon, Glossaulax didyma ($R\ddot{o}ding$) were investigated. The gastropods collected from the intertidal zone of Biin Bay, Seocheon, Korea were studied by using histological analysis and morphometric data. The gonadosomatic index (GSI) of females and males began to increase in March and reached maximum in May. Then their values sharply decreased from late in May to August due to spawning. The condition index (CI) began to increase in February and reached maximum in May, then gradually declined in the spawning period. The CI calculated for determination of the spawning period was coincided with changes in the GSI and gonadal phases. Spawning occurred between late in May to August in females and early in May to August in males. Spawning peak was observed between July and August when the seawater temperature rose to 19 $^{\circ}C$. Reproductive cycle with the gonadal development phases of this species can be divided into five successive stages in females and four in males: in females, early active stage (December to February), late active stage (February to March), ripe stage (April recovery stage (August to November); in males, active stage (December to March), ripe stage (March to July), copulation stage (early May to August), and recovery stage (August to January). Fully matured oocytes were approximately 250-270 ${\mu}m$ in size. The egg-mass was a hat in shape, and a number of egg capsules were found in an egg-mass. An egg capsule was 0.53-0.57 mm in size. An embryo (veliger larva) hatched from an egg capsule. Percentage of first sexual maturity in females and males were over 50% for individuals that are 40.1-45.0 mm in shell radius, and 100% for those that are over 45.1 mm. The sex ratio of female to male was significantly different from 1:1 $(x^2\;=\;57.22,\;p\;<\;0.05)$.

• Journal of Korean Society of Forest Science
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• v.74 no.1
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• pp.67-81
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• 1986

To investigate the stand structure of the stocked broad-leaved forests in Korea, 1,000 plots, allocated by systematic sampling method, were interpreted on the aerial photographs accompanied with ground survey. Total area of the stocked broad-leaved forests except Jeju island was 818,286ha and the percentage to total forest area was 12.7%. Total stock volume of the stocked broad-leaved forests was $38,890,779m^3$ and the percentage to total stocked forest volume was 27.4%. Mean number of trees per ha was 947 trees/ha, basal area was $11.17m^3/ha$, DBH was 11.30cm, tree height was 7.65m, stock volume was $44.96m^3/ha$, and current annual volume increment was $3.64m^3/ha$ in total land. The 64.7, 79.8 and 52.7 percent of the stocked broad-leaved forest area were distributed at elevations of 300-900m, in slope degree of above 25, and in northern aspect, respectively. Standfactors were apt to get better with the increase of distance from the car road way and the village, and with the increase of elevation belt.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.6
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• pp.73-80
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• 2008

This research investigated appropriate indoor light sources and light intensities for Hedera rhombea and Saxifraga stolonifera, which are shade-tolerant and cold-resistant indoor plants. Plants were grown in wood flames of 1 m in width${\times}$1 m in length${\times}$1 m in height. Light sources were fluorescent lamp, three wave fluorescent lamp and halogen lamp that are being used in most of the subway stations in Korea, and light intensities were 200 Lux, 700 Lux and 1,000 Lux. Results are as following. 1. Hedera rhombea Hedera rhombea heights did not show differences statistically as responses to light sources and light intensities. It, however, tended to be greater with an order of 1,000 Lux, 700 Lux and 200 Lux and halogen lamp, fluorescent lamp, and three wave fluorescent lamp. Number of branch increased under fluorescent lamp than under halogen lamp or three wave fluorescent lamp, and increased under higher light intensities. Number of leaf was higher with an order of three wave fluorescent lamp 1,000 Lux, fluorescent lamp 1,000 Lux and halogen lamp 1,000 Lux. Leaf shape became wider under low light intensities regardless of light sources. Chlorophyl contents in leaf were not significantly different under three wave fluorescent lamp and halogen lamp. However, the contents increased with an order of 200 Lux, 700 Lux and 1,000 Lux under fluorescent lamp. 2. Saxifraga stolonifera The plants were dead or declined under fluorescent lamp regardless of light intensities. When light intensities went under 200 Lux, Saxifraga stolonifera showed poor growth for all the light sources. Plant height, number of shoot, number of leaf, leaf width and leaf length have increased with an order of halogen lamp 1,000 Lux, three wave fluorescent lamp 1,000 Lux and three wave fluorescent lamp 700 Lux. Chlorophyl content was greater with an order of three wave fluorescent lamp 700 Lux, three wave fluorescent lamp 1,000 Lux and halogen lamp 1,000 Lux.

• Journal of Animal Science and Technology
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• v.54 no.2
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• pp.141-147
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• 2012

The present survey was conducted to provide basic information on Hanwoo calf management. Eight hundred and sixty-two Hanwoo breeding farms from all nine provinces were surveyed via personal interviews. The percentages of farms categorized by herd size were 30.5%, 32.8%, 26.0% and 10.7% for <50 heads, 51-100 heads, 101-200 heads, and >200 heads, respectively. More than 50% of farms offered calf starter at 6-10 days of age, showing that calf starter was offered relatively at an earlier age. Calf starter was replaced every three days by 30.1% of farms. The percentages of farms replacing starter weekly (19.2%) were even higher than those of replacing starter daily (18.8%), suggesting that the frequency of replacing starter needs to be increased to maintain starter freshness and to increase starter intake. About one-third of farms offered forage at 6-10 days of age and 21% of farms offered even at 1-5 days of age although it has been well known that forage does not contain either nutrient density or nutrient profile necessary to stimulate rumen papillae development, especially before weaning. Furthermore, about half of farms used rice straw with calf starter. Water was offered relatively at an earlier age (1-5 days of age) by 55% of farms. Deciding when to wean calves should be based on starter intake rather than age but less than 50% of farms decided weaning age by starter intake. In conclusions, to reduce weaning age of Hanwoo calves by rapid rumen papillae development it is necessary to provide fresh starter and water by increasing frequency of starter replacing and water trough cleaning and not to feed forage before weaning.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.3
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• pp.83-94
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• 2013

The purpose of this study is to offer basic data about prototype conservation of the Orijangnim, natural monument No. 404. For this study, March to August 2010, was a literature surveys and field research, and based on this, the Delphi survey of local residents and experts meeting were diagnosed with forest back ground, spatial extent, in the form of forests, flora and vegetation of the surrounding area, so examined closely the original form. Range of the Orijangnim was presumed from Jacheon middle school entrance($N36^{\circ}05^{\prime}59.9^{{\prime}{\prime}}/E128^{\circ}54^{\prime}32.9^{{\prime}{\prime}}$) to Odong of Hwabukmyeon village entrance($N36^{\circ}05^{\prime}31.0^{{\prime}{\prime}}/E128^{\circ}54^{\prime}32.5^{{\prime}{\prime}}$). The Orijangnim in the original form of the existing forest surrounding the village along gohyeon river going back a long S-shaped about 2km is considered. The investigated vascular plants consist of total 198 taxa : 2 forms, 20 varieties, 179 species, 152 Genera, 72 Families. Most of the 60 kinds of large land plants lots of whole plants accounted for 33.3%. A main vegetation of the Orijangnim have been distributed 473 objects of 21 species, and evergreen conifers is 19% to 92 objects, on the other hand, deciduous broadleaf tree is 79% to 373 objects, so the Orijangnim can be maxed forest that deciduous broadleaf tree is dominant. When consider the composition purpose of forest, environment of location, tree size, surrounding flora and vegetation, because an original vegetation of Orijangnim is suggested Zelkova serrata, Salix glandulosa, Celtis sinensis Pers., Quercus variabilis, Quercus acutissima , Sophora japonica L., Cornus walteri Wanger. we must restore around such species of tree. Cedrus deodara (Roxb.) Loudon, Chaenomeles sinensis, Prunus yedoensis Matsum., Ginkgo biloba , Pinus thunbergii Parl., Populus tomentiglandulosa T. Lee is considered to have been planted in the last.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.613-623
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• 2000

The purpose of this study was to amount of the frictional forces with the brackets and wires, ligation methods, dry/wet, offsets, interbracket distances, velocity and to compare them each other by different conditions. This study tested 0.018'x0.025' slot sized 8 types of orthodontic bracket systems and 0.016', 0.016'x0.022' sized stainless steel, NiTi, Cu-NiTi orthodontic wires. One cuspid bracket were positioned on the slide glass and archwire was engaged into bracket and ligated with elastomeric modules. The values of frictional forces were measured with the instron universal testing machine. The results were as follows; 1. Polycrystalline ceramic bracket had the highest mean frictional forces and followed and by ceramic reinforced plastic bracket, metal bracket, plastic bracket with metal slot, monocrystalline ceramic bracket, single bracket, self-ligating bracket, friction free bracket in descending order. The self-ligating bracket showed low frictional forces in the round wires and high frictional forces in the rectangular wires. 2. Stainless steel wires had the least frictional forces and followed by NiTi, Cu-NiTi wires in descending order. Round wires had lower frictional forces then that of rectangular wires. 3. The stainless steel ligation method had significantly greater mean frictional forces them the elastomeric module ligation method. 4. Artificial saliva statistically increased the frictional forces in stainless steel wire, NiTi wire and Cu-NiTi wire. 5. There was a statistically significant difference with offset change 6. There was no statistically significant difference with interbracket distance in stainless steel wires but a significant difference in NiTi wires as the interbracket was decreased. 7 There was no statistically significant difference with velocity change. From the above findings, self-ligating bracket, stainless steel wires and the elastomeric module ligation method might be effective than any other materials to reduce the frictional forces in the orthodontic treatment and can be correlated to clinical situations seen in orthodontic patient care.

• The Journal of Dong Guk Oriental Medicine
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• v.7 no.2
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• pp.121-140
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• 1999

The various oriental herbal medicines, which have usually been used for treatment of reducing fever, purging intense heat and detoxication, were screened to determine the antibacterial activity and the minimal inhibitory concentration against pulmonary disease-causing Klebsiella pneumoniae, Streptococcus pyogenes, and Streptococcus pneumoniae. The results obtained were as follows: 1. Among the 23 oriental medicines tested, the water-soluble extracts of Coptis japonica, Scutellaria baicalensis and Picrorrhiza kurrooa showed the antibacterial activity against K.pneumoniae and that of C. japonica against S. pyogenes. The antibacterial activities of C. japonica, Prunusmume, Schizandra chinesis, Scutellaria baicalensis were also found against S.pneumoniae. When C.japonica was used, the high antibacterial activity was shown against Bacillus subtilis and other extracts showed a little activity against B. subtilis and E. coli as a control. 2. The ethanol-soluble extracts of Patrinia scabriosaefolia, P. mume, S. baicalensis, S. chinesis showed the antibacterial activity against K. pneumoniae and those of S. baicalensis, C. japonica, S. chinesis, P. mume agaist S. pyogenes and S. pnuemoniae. However, those extract showed a little antibacterial activity against B. subtilis and E. coli except for that the extract of C. japonica showed comparatively high growth inhibition of B. subtilis. 3. Among the medicinal herbs tested, the water and ethanol extrats of C. japonica showed very extcellent antibacterial activity against the pathogenic bacteria and controls. 4. When the water-soluble extracts of C. japonica and S. baicalensis, minimal inhibitory concentrations (MICs) against K. pneumoniae were $10mg/m{\ell}$ and $22 mg/m{\ell}$, respectively. The MICs of the ethanol-soluble extracts of P. mume and P. scabriosaefolia were $5mg/m{\ell}$ and $20mg/m{\ell}$, respectively. 5. For the MICs against S.pyogenes, C. japonica showed $15mg/m{\ell}$ with the water-soluble extract and P. mume and C. japonica with the ethanol-souble extract did $5mg/m{\ell}$ and $10mg/m{\ell}$, respectively. 6. For the MICs against S. pneumoniae, C. japonica and P. mume with the water- and ethanol-souble extract showed $5mg/m{\ell}$ and $10mg/m{\ell}$, respectively. As a result, the highest antibacterial activity was found in the water- and ethanol-soluble extracts of C. japonica against pulmonary disease-causing bacteria, K. pneumoniae, S. pyogenes. and S. pnuemoniae. Also, the water- and ethanol-soluble extracts of S.chinesis. P.mume, S.baicalensis, and P.kurrooa showed hight antibacterial activities.