• Applied Microscopy
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• v.24 no.1
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• pp.86-101
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• 1994

The development of synovial membrane from knee joint was studied by electron microscope in human fetuses ranging from 20mm to 260mm crown rump length (40days to 30weeks of gestational age). At 40mm fetus, developing synovial tissue was observed in homogenous interzone as a vascular mesenchyme around the periphery. The primitive joint space was appeared after the intermediate layer of the interzone in direct contact with chondrogenic layer at 60mm fetus. Differentiation of the synovial membrane coincided with clarification of the joint cauity. When dilatation of the synovial cavity occurred, the two types of synovial cells were well endowed with rough endoplasmic reticulum. At 100mm fetus, type A cells with a markedly attenuated cytoplasm were found as well as those cells which contained pinocytotic vesicles and vacuoles. By 150-200mm fetuses a majority of the intimal cells were type B. These cells were characterized by abundant rough endoplasmic reticulum and well developed Golgi complex. In contrast, A-type cell had numerous filopodia, pinocytotic vesicles lysosomes, and large vacuoles containing amorphous material. At 260mm fetus, the intimal cells were well developed and plentiful. The most marked difference between the synovial membrane of full-term fetus and adult was the large amount of collagen in the latter. During fetal period, the B-cells were most numerous cell type in the intimal cells. The B-cells were clearly distinguishable from the A-cells by their content of extensive rough endoplasmic reticulum and well developed Golgi complex.

• Korean Journal of Environment and Ecology
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• v.8 no.2
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• pp.167-176
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• 1995

Autumn visitors to Chuwangsan National Park was more than summer's. About 89% of total visitors used main trail but approximately 35% visited to the Third Falls. The entire width, bare width, maximum depth and slope of trail as the trail condition surveyed at the total of 103 points were significantly greater on the more heavily-used trail. Trail conditons of rock-exposed, root-exposed, deepening points as the deterioration types of trail were significantly different from those of non-deteriorated points. According to the topographic position of trail, severe difference of dominant trees in the edge vegetation was found and Lespedeza maximowiczii, Rhododendron yedoense and Fraxinus sieboldana were dominant in shrub layer of trail edge vegetation. The crown coverage, number of species and individuals of shrub layer in edge vegetation were generally higher than those in the other national parks with more heavily-used trail.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.68-78
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• 1991

To investigate edge vegetation structure and species in the Chrisan National Park, filed survey was excuted from August to October, 1991 and the results were as follows. Importance values of species in lower layer were changed according to the distance from edge to forest interior at the northeastern slope of a highland. Change of vegetation structure was observed from edge up to 30m of forest interior and edge depth was estimated as 15~20m. The dominance and frequency of edge species seemed to be affected by the factors of altitude, aspect and topographic location. Especially, edge vegetation showed severe difference according to topographic location between a ridge and a foot of a mountain, and according to aspect between southern and northern slope above midslope region of a mountain. Comparing vegetation structure of lower layer for southern and northern slope, more no. of individuals and crown coverage were observed at northern slope, while more no. of species, species diversity and coverage of Sasa purpurascen at southern slope.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.5
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• pp.59-69
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• 2003

Most denuded mountain areas in Korea were completely stabilized by the successful work of the 1st and 2nd 10-year Forest Development Plans which targeted the reforestation of denuded forest lands. The objectives of this study are (1) to estimate the depth of organic horizon in the soil profile, (2) to investigate the change of vegetation structure, (3) to estimate the change of biomass in the erosion controlled and rehabilitated mountain areas with the passage of time. This study was carried out as the 5th times. The first study began in the year of 1985, the second study was in the year of 1988, the third study was in the year of 1992, 4th was in the year of 1998 and 5th was in the year of 2002. The first study started in the study sites which elapsed 9 years after erosion control works. The results of the study were as follows : The increase rate of soil thickness was estimated to $Y_{(cm)}=2.906log_{(yr)}-3.2476(r^2=0.917)$ during 26 years after erosion control works. The important value of pines decreased to 14.7% on upper layer. But, the important value of alders. which did not plant on erosion control work increased to 27.1%. The decrease of whole crown projection indicates that pines. and alders were heavily injured by pine leaf gall midge in the year of 1993, 1995 years and Agelastica coerulea Baly in the year of 1986, 1987 years at Yoju-gun. The young growth of pines and alders not appeared on the soil surface which elapsed 26 years after erosion control works. On the lower layer, oaks occupied over 50% in I.V, RD, RC, RF. In process of years, the increase of biomass estimated to be $Y_{(t/ha)}={0.7505X_{(yr)}}^{1.6335}\;(r^2=0.9712)$ for 26 years after erosion control works.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.21-31
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• 2010

Although it is important to reflect the accurate information of the ground condition in the tunnel design, the analysis and design are conducted by limited information because it is very difficult to get it practically on considering various geography and geotechnical condition. So construction management of information concept is required to manage immediately on the field condition because it is very time-consuming to establish the countermeasure of underground reinforcement and the pattern change of Bo. Therefore, when construction is on tunnel area, examination of accurate safety and prediction of behavior is performed to overcomes the limit of predicting behavior by using Artificial Neural Network(ANN) in this study. Firstly, the field data was secured. Secondly, suitable structure was made on multi-layer perceptrons among the ANN. Thirdly, learning algorithm-propagated applies to ANN. The data for the learn of field application using ANN was used by considering impact factors, which influenced the behavior of tunnel, and performing credibility analysis. crown displacement, spring displacement, subsurfacement, and rock bolt axial force are predicted at the tunnel construction and on-site application was confirmed by using ANN from analyzing and comparing with measurement value of on-site. In this study, the data from Seoul Highway $\bigcirc\bigcirc$ tunnel section was applied to the ANN Theory, and the analysis on the investigate value and the reasoning for the value associated with field application was performed.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.468-476
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• 1998

The purpose of this study was to observe the morphologic change of dentinal surface, adhesion in interface between dentin and bonding agents, and penetration pattern of resin tags into dentinal tubles according to bonding procedure of ONE-STEP universal adhesive system. Ten extracted human molars were mounted in dental stone and sectioned to expose mid-coronal occlusal dentin and again sectioned tooth crown apically. Specimens were randomly assigned to three groups for dentin conditioning with 32% phoshoric acid, two coats of bonding agents after dentin conditioning, and bond of composite resin. The surfaces of dentin were treated with etch ant and applied bonding agent, and bonded composite resin according to the directions of manufacturer. Specimens which were boned composite were sectioned longitudinally for observing interfaces between resin and dentin. Two of specimens which were sectioned longitudinally were immersed in 6 N HCL for 30 seconds and 1% NaOCL for 12 hours to partially demineralize and deproteinize the dentin substrate. Each specimen was mounted on a brass stub, sputter-coated with gold and observed under SEM. The result were as follows : 1. On the dentinal surface which was conditioned with 32% phosphoric acid. the smear layer was completely removed. orifices of dentinal tubules were opened 3-$5{\mu}m$ wide. and dentinal surface was irregular. 2. On the dentinal surface which was applied ONE-STEP. bonding agent. resin particles were observed on the orifices of dentinal tubules and intertubular dentin. 3. There were close adaptation between dentin and resin and were the pattern which composite invaded into dentin. 4. 1-$3{\mu}m$-wide hybrid layer was visible in the interface between dentin and resin. 5. Long and funnel shaped resin tags were observed in demineralized specimens. and the surfaces of tags were rough.

• Journal of Forest and Environmental Science
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• v.37 no.3
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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.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.120-125
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• 2014

Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.

• Journal of computational fluids engineering
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• v.17 no.2
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• pp.11-20
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• 2012

In this paper, the authors test various open codes and commercial codes based on CFD technology on the wind field around the complex terrain, which is a very important transport physics in the event of forrest fire. To study the physical mechanism inside the transition from surface fire to crown fire, the wake flow behind a parallel array of trees is studied numerically to show the flow separation in the turbulent boundary layer. Two sites near to Kunsan National University are chosen for the measurement of real wind field, and obtained data are compared with those from various computational codes such as Wind-Ninja, NIST-FDS, ANSYS-CFX, and ANSYS-FlUENT, etc. Through this research, feasibility and accuracy of the present CFD codes are investigated quantitatively, compared with the measured data with AWS.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.416-424
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• 1999

Simulation of naturally appearing enamel in fixed prosthodontics could be achieved with all ceramics. The purpose of this study was to investigate the stain resistance of 4 different all ceramics materials (In-ceram, IPS Empress, Celay, Vintage). Forty specimens were prepared using manifacture's instruction and the samples were divided into two groups. The specimens for one group were glazing and those for other group were ground to remove the glazing layer. All specimens were immersed in methylene-blue for 24hours. The color values for each specimen was measured with colorimeter (Mode Tc-6Fx, Tokyo Denshoku Co.) prior to and after immersion in methylene-blue. The following conclusions were drawn from this study. 1 The stain resistance of glazing ceramics was higher than that of unglazing ceramics. 2. The changes of ${\Delta}E^*$\;and\;L^*$ values were revealed in Vintage and unglazing Celay. 3. The changes of $a^*$ values were revealed in unglazing vintage, Celay, In-ceram. 4. The changes of $b^*$ value were revealed in Vintage, IPS Empress and unglazing Celay.