• Journal of Microbiology and Biotechnology
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• 제30권6호
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• pp.848-855
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• 2020

Land subsidence induced by underground coal mining leads to severe ecological and environmental problems. Arbuscular mycorrhizal fungi (AMF) have the potential to improve plant growth and soil properties. We aimed to assess the effects of AMF on the growth and soil properties of sea buckthorn under field conditions at different reclamation times. Inoculation with AMF significantly promoted the survival rate of sea buckthorn over a 50-month period, while also increasing plant height after 14, 26, and 50 months. Crown width after 14 months and ground diameter after 50 months of inoculation treatment were significantly higher than in the uninoculated treatment. AMF inoculation significantly improved plant mycorrhizal colonization rate and promoted an increase in mycelial density in the rhizosphere soil. The pH and electrical conductivity of rhizosphere soil also increased after inoculation. Moreover, after 26 and 50 months the soil organic matter in the inoculation treatment was significantly higher than in the control. The number of inoculated soil rhizosphere microorganisms, as well as acid phosphatase activity, also increased. AMF inoculation may play an active role in promoting plant growth and improving soil quality in the long term and is conducive to the rapid ecological restoration of damaged mining areas.

• 대한치과기공학회지
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• 제34권2호
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• pp.75-81
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• 2012

Purpose: All ceramic crown, made from zirconia instead of metal for core material, is recognized the best esthetical prosthesis. Recently, high-priced zirconia blocks and expensive CAD/CAM machines come into use for making zirconia core. In this study, slip casting process is adapted to evaluate the possibility of the recycling the remained parts of zirconia block after machining. Methods: Remained zirconia blocks were reduced to powders with zirconia mortar, and screened with 180 mesh sieve. Passed powders were ball milled under various conditions to obtain the optimum zirconia slip for casting. Solid casting method was used for casting the specimens with plaster mold. Formed specimens were dried and biscuit fired at $1,000^{\circ}C$ for 1 hour. Biscuit fired specimens were finished with exact shape of square pillar. Finished specimens were fired from $1,200^{\circ}C$ to $1,550^{\circ}C$ at $50^{\circ}C$ intervals for 1 hour. Linear shrinkage, apparent porosity, water absorption, bulk density, and flexural strength were tested. Microstructures were observed by SEM. Results: Above examinations indicated that the optimum firing temperture was $1,500^{\circ}C$, and when fired at this temperature for 1 hour, apparent porosity was 0% and flexural strength was 680MPa. SEM photomicrographs showed uniform 200~300nm grain size, which is equal with microcture of sintered commercial zirconia block. when compare 24% linear shrinkage of cast specimen with 20% linear shrinkage of CAD/CAM machined block, it was estimated that the size controlling of cast core was not so difficult. Conclusion: According to the all of this experimental results, the cast zirconia core produced from the remained parts of zirconia block was possible to use for all ceramic denture.

• 한국산림과학회지
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• 제99권6호
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• pp.863-870
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• 2010

산지에서 재배되는 산양삼의 생육특성을 알아보기 위하여 재배지 내에 $20{\times}20$ m 방형구를 설치하고 설치된 지역의 입지 및 토양 특성을 조사하였다. 입지특성에 관해서는 상층을 위주로 매목조사를 실시하였다. 임관울폐도는 균일하게 80%로 조절하고, 조사지내의 시험구는 미세기후를 측정하기 위한 Hobo를 설치하여 재배지의 기온, 토양내 온도변화 등을 측정하고 지역적 특성을 조사하였다. 시험구의 입지특성은 모든 조사구에서 다양하게 나타나고 있다. 또한 시험구내의 토양 특성은 우리나라의 전형적인 산림토양의 특성을 나타내고 있다. 특히 4월경 지상부가 출현하는 시기에는 $15^{\circ}C$이상의 적온이 필요한 것으로 나타났다. 지중온도가 상승하여 $8^{\circ}C$에 도달하면, 산양삼의 정단부에서 출엽을 시작하며, 지중온도가 $18^{\circ}C$를 넘어서면 낙엽이 지기 시작한다. 묘삼 식재의 경우 초기 출아율이 높으나 3년이후 급격히 출아율이 감소하여 자연도태가 이루어지고, 종자 파종의 경우에는 초기 출아율이 묘삼식재보다는 낮으나 자연도태율이 묘삼식재보다 낮은 것으로 나타났다.

• Journal of Ginseng Research
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• 제7권2호
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• pp.172-192
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• 1983

Light environment and growth of Panax ginseng In habitat and cultivation under natural shade were renewed. Grower's experiences on ginseng stand In relation to light environment were assessed. Change of shading method and grower's concepts on light requirement of ginseng plant in Korea, Manchuria and Japan was counted. Growth of wild ginseng was better under rich light. Optimum crown density index appeared to be 0.7 In natural habitat and 0.4 to 0.7 for the cultivation in forest. Change of light Intensity in forest was greatest in May and reached near to constant value (from 40% to 3% for broad leaf deciduous forest and loom 4% to 2% for pine forest). Insufficient light condition induced long and thin stem, poor flowering and seed bearing, and sequent dormancy. Relation between light and ginseng strand was not clear but light Interception with cool weather was effective. Topography and orientation of bed have been deeply considered for light environment. Panel or bark of won were used for shading in deep forest manly In Manchuria while reed blind and straw thatch were used in Korea. Kinds and number of shades material and seasonal or daily schedule have been simplified probably by labor pressure due to eulargement of plantation. Post height has been greater while width of roof, bed and ditch has changed lisle. Scientific survey in the past omitted important light control methods (complete light hardening etc) which has been practiced in specific areas. The concept and technique of light control in the past in Korea were delicate and intensive including the control of temperature and moisture. For the application of old concept in modem cultivation precise Investigation of the technique including the measurement of light, temperature and moisture is needed.

• 환경영향평가
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• 제7권2호
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• pp.37-51
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• 1998

This study was carried out to lead the scientific management of the urban forest by estimating the forest environment. Forest environmental information was constructed using IDRISI system based on survey data, soil, plant, and digital elevation data. Forest environmental information was consisted of soil depth, soil organic content, soil hardness and parent rock as a soil environmental factor, and forest community, tree age, crown density as a plant environmental factor. Plant activity and topographic environment also were analyzed by using remote sensing data and digital elevation data. Environmental function of urban forest was estimated based on results of soil conservation and forest productivity. 70% of urban forest is located in elevation of lower than 200m and 55% of forest area have the slope of lower than 15 degree. Analyzed soil conservation status and forest productivity were almost the same as the soil chemical properties of collected soil sample and the vegetation index estimated using remote sensing data, respectively. Thus, the constructed forest environmental information could be useful to give some ideas for management of urban forest ecosystem and establishment of environmental conservation planning, including forests, in Taejon. The best forest environmental function was appeared at the natural ecology preservation zone. Current natural parks and urban parks were appeared to establish the environmental conservation plan for further development. The worst forest environmental function was appeared at the forest near to the industrial area and an overall and systematic plan was required for the soil management and high forest productivity because these forest was developing a severe soil acidification and having a low forest productivity.

• 한국환경생태학회지
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• 제13권1호
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• pp.34-48
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• 1999

본 연구는 주요 조경수목에 대한 생장예측모델을 추정하여 적정 식재간격을 산정하기 위해 실시하였다. 조경식재에서 많이 사용되는 9개 수종을 대상으로 수종별 30주 이상씩의 개체를 선정한 후, 상관성이 높은 측정변수 간에 회귀분석을 실시하여 생장예측모델을 추정하였다. 그리고 서울 시내 2개 아파트단지 녹지를 사례연구지로 선정하여 생육상태를 파악하고 모델과 비교하였다. 전체적으로 교목층 위주의 식재로 인해 식재밀도가 과밀하여 수관이 왜곡되고 기형적으로 생장하는 현상이 발생하고 있는 바, 수관중복률과 수관왜곡률을 분석한 결과에 의하면 현재의 식재간격이 매우 조밀한 것으로 밝혀졌다. 결론적으로 시간경과에 따른 주요 조경수종의 규격별 생장예측을 통해 목표년도별 적정 식재간격을 제안하였는데, 목표년도를 식재 후 5년으로 본다면 상록교목은 2.0m, 낙엽교목은 3.0~4.0m, 낙엽아교목은 2.0~2.5m의 식재간격이 적당하고, 식재 후 10년을 목표년도로 한다면 상록교목의 경우 3.0m, 낙엽교목은 4.0~6.0m, 낙엽교목은 2.5~3.0m의 간격을 유지하여야 한다. 한편, 본 연구의 결과와 서울시 조례기준 식재밀도를 비교하였는데, 식재후 5년이 경과한 시점에서는 0.23본/m2, 10년 경과시점에서는 0.12본/m2이 적정 식재밀도로 밝혀져 현재 0.2본/m2으로 정하고 있는 서울시 교목식재 관련 기준은 5년 정도를 목표시점으로 한다면 적절한 수준임을 알 수 있었다. 그러나 식재 후 10년이 경과하면 수관중복률이 25%를 초과하게 되므로 쾌적한 녹지환경을 유지하기 위해 반드시 적절한 관리를 실시해야 할 것으로 판단되었다.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.180-192
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• 2000

One bottle system was recently developed in order to simplify the clinical skills and save chair time after continuous improvements on dentin bonding agents. There has been many studies to measure the bond strength of one bottle systems but no actual work has been done on micromorphologic study of resin-dentin interdiffusion zone after one bottle system application. To evaluate the bonding patterns of various commercially available one bottle systems to dentin, observation of resin-dentin interdiffusion zone under TEM was performed. Caries-free human third molars within one month of extractions were chosen for the experiments. The molars were sectioned 1mm above the cementoenamel junction and got rid of the root portions. Crown portions of the teeth were sectioned parallel to occlusal surface so that dentin discs of 1mm in thickness were remained. 7 one bottle systems and 1 two bottle system were applied according to manufacturer's instructions and followings were the results. 1. In every experimental groups, cross bandings of collagen fiber were distinguishable and tight bon dings between the bonding agents and dentin were observed. 2. Hybrid layer was clearly observed in ONE-STEP$^{(R)}$, Prime & Bond$^{(R)}$ 2.1, Syntac$^{(R)}$ SC, MAC-BOND II groups but it was not clear in Single Bond, D-Liner Dual PLUS, ONE COAT BOND groups. 3. Electron-density of hybrid layer was uniform in pattern in MAC-BOND II, Prime & Bond$^{(R)}$ 2.1 groups but not so uniform in ONE-STEP$^{(R)}$ group. 4. Electron-dense amorphous phase in most superior layer of the resin-dentin interdiffusion zone was characteristically observed in Single Bond, Syntac$^{(R)}$ SC, ONE COAT BOND groups. It can be concluded that bondings between the dentin bonding agents and dentin can be various in pattern according to their chemical compositions and the condition during applications.

• Journal of Forest and Environmental Science
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• 제27권3호
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• pp.169-181
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• 2011

The purpose of this study was to understand the geographical and environmental distribution of animals and plants in Baekdudaegan region using field survey and GIS data. Crucial factors were selected and analyzed to understand the distributional characteristics of wild animals (16 species in 5 orders) and rare endemic plants (20 species in 12 orders). These crucial factors include stand factor (forest type, DBH class, and crown density), soil factor (bed rock, soil texture, and organic matter), geographical factor (elevation, slope, aspect) and climatic factor (temperature, rain fall, humidity). Finally, ten crucial factors were selected by statistical analysis and categorized for analyzing geographical and environmental features. Three orders such as Rodentia, Carnivora, and Artiodactula in wild animal showed the similar habitat characteristics with the small diameter and the elevation range from 801 to 1,000m. The Hydropotes inermis of Artiodactyla and Rattus norvegicus of Rodentia were different in the type of orders, but they had the similar habitat characteristics with the coniferous forest and loam. On the other hand, four orders such as Tubiflorales, Liliales, Ericales, and Rhamnales in the rare and endemic plants were showed high occurrence rate in the organic matter between 4 and 6%. The Rodgersia podophylla of Rosales and Gastrodia elata Blume of Microspermae were different in the type of orders, but they had the similar habitat characteristics with the stand factor and soil factor.

• Journal of Forest and Environmental Science
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• 제37권3호
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• pp.206-216
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• 2021

Deutzia paniculata Nakai, a rare and endemic plant, has limited distribution throughout the North and South Gyeongsang provinces of South Korea. The D. paniculata community grows mostly on the stony slopes of forests, valley edges, and rock layers at 250-960 m in altitude, where deciduous trees are dominant and high humidity is maintained. Correlation analysis of vegetation and environmental factors found that the Walter's dogwood-mulberry community was correlated with soil acidity (pH). Whilst the queritron community had correlations with distance from the valley, rock rate and slope. The natural habitat of the Palgongsan Mountain in Daegu is known to have high genetic diversity, had eight D. paniculata individuals recorded from 2014 to 2018, and 12 individuals recorded in 2020 (new individuals due to a newly created space within the herbaceous layer caused by grass mowing works), it is therefore unlikely that the community would perish unless there was an artificial disturbance. To conserve the natural habitats of D. paniculata, oppression by Sasa borealis, damage, increase in crown density of the upper layer, overexploitation, and absence of seedlings should be carefully investigated. In addition, response measures should also be established and the impact on seed fullness and the reproductive characteristics of D. paniculata recorded. To restore declined genetic diversity, individuals from high genetic diversity regions, such as Palgongsan Mountain, should be artificially transplanted.

• 한국산림과학회지
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• 제107권4호
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• pp.478-485
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• 2018

본 연구에서는 백두대간 등산로 훼손에 영향을 미치는 자연환경요인을 선정하고 영향 관계를 분석하였다. 연구대상지는 백두대간 고루포기산~생계령 구간 내 표본지 총 123개소이며 등산로 훼손, 임상, 하층식생, 수관밀도와 FGIS를 통해 얻은 경사, 토성, 암석노출 총 7가지 정보를 분석에 활용하였다. 등산로 훼손 발생지 43곳과 미발생지 80곳을 로지스틱 회귀분석을 통해 분석한 결과, 등산로 훼손에 영향을 미치는 자연환경요인으로 경사도, 하층식생, 토성, 암석노출 총 4가지를 선정하였다. 경사도와 하층식생은 양의 상관관계를 보였고 암석노출은 음의 상관관계로 나타났다. 토성은 미사 비율이 낮고 모래 비율이 높은 토성일수록 양의 상관관계를 보이는 것으로 나타났다. 따라서 등산로 훼손을 줄이기 위해서는 경사도, 하층식생, 토성, 암석노출 4가지 자연환경요인들을 적절하게 관리하여야 한다.