• Korean Journal of Plant Taxonomy
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• v.31 no.3
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• pp.253-265
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• 2001

Cymopterus melanotilingia (Apiaceae) was reviewed by external morphology and cross-section of leaf-margin and mericarp, and the taxonomic position of species and genus was reexamined. Based on these results, the description and adistribution map of C. melanotiligia were obtained. The leaf-margin forms a collenchymatous ridge by projecting toward the lower part. One mericarp has 2-lateral ribs and 2-intermediate ribs and the other mericarp has 2-lateral ribs and 1-dorsal rib, suggesting each of them is asymmetric. These characters show that this species does not belong to the genus Ostericum s.s., but should be treated as the genus Cymopterus.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.1.2-6
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• 1990

The purpose of this experiment was to investigate boron deficient symptom of sugar beet. Sugar beet affected by boron deficiency was anatomized and observed by microscope and electron microscope. The sugar beet plants affected onboron deficiencyu with water culture and those of the experimental farm alike contained a small amount of boron. The symptom of boron deficiency began to show dark-brown lines at the ventral suface of the basal part of petiole and then, in the ridge of young leaf, growing point became darkened due to necrosis. The leaf blade was wrinked severely and finally the growth was stunted. The boron deficiency began with necrosis of the epidermis of the ventral surface of the basal part of petiole, and parenchyma under it. Necrosis and disintegration of the ridge of young leaf began to take place and were expanded gradually. Electron microscopic examination of boron deficient sugar beet plants revealed that chloroplasts degenerated, and appeared to contain larger amounts of starch, also observed larger number of osmophilic granules. And they peculiarly were found polyhedral crystals in the certain deficient chloroplasts.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.3
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• pp.351-384
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• 1993

Complete denture occlusion must be developed to function efficiently and with the least amount of trauma to the supporting tissues. For the preservation of supporting tissues, it is imperative to reduce to a minimum the functional stress induced by dentures. The magnitude of the horizontal component of functional stress contributed by various occlusal teeth forms has not been studied. This study was aimed to investigate the influence of different occlusal teeth forms on the mode of distribution of the stresses in the mandibular tissue, and the displacement of lower dentures during the variant functional movement of mandible for this study three dimensional finite element analysis was used. FEM models were created using commercial software Super Sap for IBM 32 bit computer. The model was composed of 3380 brick elements and 4346 nodes. The results were as follows. 1. The magnitude of stress was similar between two models in centric occlusion, in the case of anatomic model, the stress was concentrated on the buccal side of alveolar ridge beneath the bicuspids. 2. During the protrusive movement, the increasing of stress from the posterior to anterior part of mandible was seen in the case of anatomic model. 3. During the lateral movement, the stress of anatomic model was greater than that of nonanatomic model. 4. The stress of anatomic model was concentrated on the anterior region of residual ridge during the lateral movement. 5. In the case of anatomic model the anterior part of denture was displaced severely at the centric and lateral position, but the denture of nonanatomic model was displaced minutely at the protrusive and lateral position.

• Journal of The Geomorphological Association of Korea
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• v.23 no.1
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• pp.35-45
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• 2016

Aiming to elucidate the formation processes of Myeonsan wetland around the ridge from Myeonsan peak to Seokgae pass, this paper analyzes the geomorphic, physical and chemical characteristics of the wetland. The results are as follow: Firstly, resistant bedrock and big boulders distributed on the riverbed of the small channel from the wetland to Seokgaecheon have played a role as a temporary base level. At the upstream part above this point, a wide and shallow depression was formed and developed into a wetland. There was a gorge covered with boulders at downstream part. Secondly, owing to the obstacles at the outlet of wetland, deposits on bed tend to be downstream coarsening. Finally, deposits show weak acidity of pH 5.0~5.7. The source of wetland water is groundwater containing rich Ca and Na. Trees in the wetland help much more Ca accumulated. And deposit biotite and amphibole contained rich Mg have been weathered in the wetland.

• Korean Journal of Environment and Ecology
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• v.33 no.6
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• pp.686-694
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• 2019

This study was carried out to identify the long-term changes to beech forest due to climate change in Ulleung-do. To study the traits of the stand structure of beech forest with micro-topography, we investigated the distribution of the basal area, important values, and indicated species in a small ridge between Albong basin and Seongin-bong peak, and 1-ha stands (20 m × 20 m, 25 sites) dominated beech species including on the upper slope and valley parts. The result showed that the indicator species characterizing the vegetation communities were Tsuga sieboldii, Rhododendron brachycarpum, and Mitchella undulata in the small ridge and Celtis jessoensis, Dryopteris crassirhizoma, and Ulmus laciniata in the valley part. Moreover, the individuals with the total DBH < 10 cm were more predominant in the small ridge and upper slope than in the valley part, the individuals with DBH = 10-25 cm were predominant in the small slope, and individuals with DBH = 25-45 cm and DBH > 45 cm were predominant in the upper slope. The reason for the predominant distribution of beech stand with DBH<10 cm in all terrains is suggested to be germination by nutritional propagation rather than secondary succession caused by artificial disturbances and seed propagation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.4
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• pp.324-331
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• 2001

The present study was aimed to investigate the effects of latency period on alveolar ridge distraction using the intraoral distraction device. Nine adult mongrel dogs of either sex, weighing about 15kg, were used. They were divided into 3-day, 5-day, and 7-day groups according to the latency period. The left upper and lower premolars and first molars were extracted. Twelve weeks after the extraction, an osteotomy was performed and the distraction device was applied. After the latency period, the distraction was applied at a rate of 1.2mm for 8 days. The distraction device was left in place for 2 weeks to allow consolidation and was then removed. The animals were sacrified at 8 weeks after completion of distraction and were examined macroscopically, radiographically, and histologically. After completion of the distraction, the alveolar crest protruded prominently, showing the vertical augmentation of the alveolar bone. Soft tissues were broken down after the 6th day of distraction in 3-day latency group, and premature union occurred on the 7th day of distraction in the 7-day latency group. The average distance was $9.40{\pm}0.3mm$ in 3-day latency group, $9.35{\pm}0.1mm$ in 5-day latency group, and $8.85{\pm}0.1mm$ in 7-day latency group. In the radiograph taken at 8 weeks after distraction, there was slight bone resorption around the medial and distal edges of the alveolar bone segment, and a new bone deposition was observed in the neighboring alveolar crest area in all groups. Fibrous tissues were present in a part of the buccal cortical bone area of the distraction gap, and the woven and lamellar bones were observed in the distracted gap. There were bony bridges in the distraction gap in all animals examined. These results suggest that optimal time of latency period on alveolar ridge distraction using the intraoral distraction device is about 5 days in dogs, and about 7days in human beings.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.81-92
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• 2008

Fonualei Rift and Spreading Center(FRSC) and Mangatolu Triple function(MTJ) caldera are located in northeastern part of Lau basin which is the active back-arc basin. Deep-tow and surface-tow magnetic surveys are carried out in FRSC. In deep-tow magnetic survey, to compensate for influence of uneven distance between bathymetry and sensor height, magnetic anomaly is continued upward to a level plane by using the Guspi method. We calculate crustal magnetization using Parker and Huestis's inversion algorithm, and try to find the hydrothermal vent and understand the structure of ocean floor crust. The result of deep-tow magnetic survey at FRSC showed that Central Anomaly Magnetization High(CAMH) recorded the max value of 4.5 A/m which is associated with active ridge. The direction of SSW-NNE corresponds with the direction of the principal spreading ridge in Lau basin. The low crustal magnetizaton$(174^{\circ}35.1'W,\;16^{\circ}38.4'S)$ of -4.0 A/m is supposed to correlate with submarine hydrothermal vent. Surface-tow magnetic data were collected in MTJ caldera$(174^{\circ}00'W,\;15^{\circ}20'S)$. The prevailing SSW-NNE direction of collapsing walls and the presence of CAMH at the center of caldera strongly indicate the existence of active spreading ridge in ancient times.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.403-407
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• 2000

Ultrastructure and function of testis somatic cells in freshwater prawns Macrobrachium nipponense were studied. The paired testes of the prawn were elongated, united at their anterior end, which lay between the dorsal surface of the hepatopancreas and the heart. Each testis consisted of a large number of seminiferous cords compactly held together by connective tissue. A seminiferous cord was composed of an outer layer of simple squamous epithelium, a basement membrane, the closely packed germ cells and sustentacular cells of the germinal ridge, and an inner layer of simple cuboidal epithelial cells. Leydig cell-like cells in an angular areas filling the space of the seminiferous cords were observed. The nuclei of leydig cell-like cells were characterized by a distinct nucleolus. The simple squamous epithelial layer was composed of flattened cells tying on a basement membrane. The nuclei of the flattened cells were often overlapped in a layer, and the cytoplasm of the cells was observed just near the nuclei. The sustentacular cells were complex in morphology. These cells had relatively small cell bodies from which long cytoplasmic extensions ramified reached the space of germ cells in the germinal ridge. The nuclei of sustentacular cells usually exhibited angular profiles and located most commonly at the periphery of the cords. Cells of simple cuboidal epithelium located between germinal ridge and lumen of seminiferous cord, and part of the cells were adjacent to basal lamina, The cuboidal epithelial cells contained numerous mitochondria, the well-developed rER, the well-developed Golgi complex, and irregularly shaped nuclei. Transition vesicles appeared on the cis side of the Golgi complex. The large vesicles on the trans side of the complex appeared to fuse to form a membrane-bound structure. A number of pits on the cell apex suggested exocytotic activity for secretion of the sperm supporting matrix.

• 한국해양학회지
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• v.23 no.1
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• pp.24-40
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• 1988

In the Korea Ocean Nodule Development (KONOD)-1 area between the Clarion and Clipperton fracture zones of the northeastern equatorial Pacific, the pelagic sediment layer can be divided into two or three units on air-gun seismic profile. The acoustic units can be also correlated with those in the DSDP site 163 core. The topmost unit (unit I) is acoustically transparent and consists of zeolitic clay and radiolarian ooze of late Oligocene to middle Eocene age. Unit IIA is well-stratified and transparent in the lower part. consisting of the radiolarian ooze intercalated with chert beds and zeolitic clay of early Eocene to Paleocene age. Unit IIB is stratified with layers of silicified and compacted flinty-cherty nannofossil chalk (late Cretaceous) on top of the acoustic basement. Units I and IIA form the Line Islands Formation that overlies an unnamed formation of unit lIB. The entire layers and the unit I layer propressively thin northward, except near the Line Islands Ridge. The distribution of sediment layer has been controlled by the equatorial Cenozoic CCD and the northward spreading of the Pacific plate. The change of CCD corresponding to the subsidence and migration of the plate has determined the sediment composition of the DSDP 163 core passed across the equator of high sedimentation suite. The late Cretaceous sedimentary layer (unit IIB) in the 163 core was formed above the CCD south of the equator. The unit IIA resulted from rapid subsidence of the Pacific plate below the CCD in the Paleocene. The unit IIA is seen only in the west of 149 W. Both the units IIA and I were probably formed during the Pacific plate passing and after leaving the equatorial region respectively since early Eocene. In the south of the KONOD-l area, the unit I was redistributed by bottom current, a branch of the Antarctic Bottom Water flowing eastward guided by the Clipperton fracture zone. The activities of bottom currents were prolonged for a long geological time. Turbidite layers occur more than 350 km from the Hawaiian Ridge to near the Clarion fracture zone. They originated directly from the Hawaiian Ridge, filling the topographic lows.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.121-127
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• 1972

The present paper deals with the results of the comparative morphology on the urohyal bones on the right-eye flounders, pleuronectidae fishes in Korean waters. The results obtained are as follows : 1. The position of the tip of sciatic part is quite different depending on the genera and species of the fishes. The sciatic part of the genera, Platichthys and Cleisthenes, is very short extending to the middle portion of the main part. In the fishes of Eopsetta and Tanakius, it is also very short extending to the anterior 1/3 of the distance from the tip of main part. The fishes of Verasper and Dexistes have a short sciatic part which extends toward the posterior 1/4 of the distance from the tip of main part. The fishes Of Limanda, Clidoderma, Glyptecephalus and Microstomus have a long sciatic part which extends as long as the main part. However, those of Kareius and Pleuronichthys have a very long sciatic part extending twice long as the main part. The tip of sciatic part of the fishes belonging to Eopsetta, Verasper, Limanda, Platichthys, Tanakius and Glyptocephalus is a truncate form. It is pointed upward in the fishes of Kareius, Pleuronichthys, Clidoderma and Microstomus, but pointed forward in Cleisthenes and Dexistes. 2. The size and form of the cardiac apophysis vary with the developmental grades of the urohyal bone. The fishes of Eopsetta, Verasper, Platichthys, Tanakius, Kareius and Dexistes possess relatively large apophyses and those of Pleuronichthys and Clidoderma have small apophyses. Intermediate size of the apophysis is found in the fishes of Limanda, Microstomus and Cleisthenes. A long and barlike apophysis is found in Glyptocephalus. Three kinds of the cardiac. apophysis are found in the fishes examined, i. e., lateral wing in Eopsette, Verasper, Limanda, Platichthys, Tanakius, Glyptocephalus, Kareius, Pleuronichthys and Clidoderma, pointed forward in Microstomus and Cleisthenes, and truncate with a well-developed inner ridge type in Dexistes. 3. The angle of the main part and sciatic part varies from 30 to 60 degrees in the fishes studied except for the fishes of Pleuronichthys, Clidoderma and Microstomus which show a semi-elliptical form.