• Title/Summary/Keyword: upper plane

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Tectonic Features of a Triple-Plate Junction in Hokkaido Using Local Seismic Tomography

  • Kim, So-Gu;Bae, Hyung-Sub;Pak, Sang-Pyo
    • Proceedings of the KSEG Conference
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    • 2005.04a
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    • pp.101-106
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    • 2005
  • The three-dimensional Tomography developed by Kim and Bae(2004) was applied to 64,024 P and 64,618 S wave arrival times observed at 238 seismic stations for 4050 local earthquakes in the depth range from 0 to 300 km in and around Hokkaido, Japan. High and low velocity zones for Vp/Vs were clearly imaged in and around Hokkaido. The upper seismic planes of the double seismic zone (DSZ) were found in the subducted Pacific Plate beneath Hokkaido at depth of 40- 80 km, which produced high seismicity around Hokkaido. The findings of high Vp/Vs anomalies beneath the Moho discontinuity supports an evidence of a surface triple-collision hypothesis prepared by Moriya(1994) that the Kuril Arc(Okhotsk Plate or North American Plate) is colliding against the NE Japanese Arc(Amurian Plate or Eurasian Plate), along and beneath the Hidaka Mountain Range, and at the same time the Pacific Plate is subducting into these two plates, making an equilibrium of tectonic forces along the Hikada Mountain Range (HMR) corner and the central tectonic axis(142 ~ 143E) in Hokkaido. The low Vp and Vs were also found in east and west along the central tectonic axis in which the focal mechanism represents the extensional forces. These phenomena are also consistent with low Bouguer gravity anomalies in this region. It is understood why most of great earthquakes occurred outside Hokkaido where the balance of tectonic forces are breaking from the triple junction of three tectonic forces in Hokkaido.

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In situ dental implant installation after decontamination in a previously peri-implant diseased site: a pilot study

  • Kim, Young-Taek;Cha, Jae-Kook;Park, Jung-Chul;Jung, Ui-Won;Kim, Chang-Sung;Cho, Kyoo-Sung;Choi, Seong-Ho
    • Journal of Periodontal and Implant Science
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    • v.42 no.1
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    • pp.13-19
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    • 2012
  • Purpose: The aim of this study was to examine whether a previous peri-implantitis site can affect osseointegration, by comparing implant placement at a site where peri-implantitis was present and at a normal bone site. A second aim of this study was to identify the tissue and bone reaction after treating the contaminated implant surface to determine the optimal treatment for peri-implant diseases. Methods: A peri-implant mucositis model for dogs was prepared to determine the optimal treatment option for peri-implant mucositis or peri-implantitis. The implants were inserted partially to a length of 6 mm. The upper 4 mm part of the dental implants was exposed to the oral environment. Simple exposure for 2 weeks contaminated the implant surface. After 2 weeks, the implants were divided into three groups: untreated, swabbed with saline, and swabbed with $H_2O_2$. Three implants from each group were placed to the full length in the same spot. The other three implants were placed fully into newly prepared bone. After eight weeks of healing, the animals were sacrificed. Ground sections, representing the mid-buccal-lingual plane, were prepared for histological analysis. The analysis was evaluated clinically and histometrically. Results: The untreated implants and $H_2O_2$-swabbed implants showed gingival inflammation. Only the saline-swabbed implant group showed re-osseointegration and no gingival inflammation. There was no difference in regeneration height or bone-to-implant contact between in situ implant placement and implant placement in the new bone site. Conclusions: It can be concluded that cleaning with saline may be effective in implant decontamination. After implant surface decontamination, implant installation in a previous peri-implant diseased site may not interfere with osseointegration.

Setting of the range for shear strength of fault cores in Gyeongju and Ulsan using regression analysis (회귀분석을 이용한 경주·울산 지역에 분포하는 단층 핵의 전단강도 범위 설정)

  • Yun, Hyun-Seok;Moon, Seong-Woo;Seo, Yong-Seok
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.2
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    • pp.127-140
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    • 2015
  • A fault is one of the critical factors that may lead to a possible ground collapse occurring in construction site. A fault core, however, possibly acting as a failure plane in whole fault zone, is composed of fractured rock and gouge nonuniformly distributed and thus can be characterized by its wide range of shear strength which is generally acquired by experimental method for stability analysis. In this study, we performed direct shear test and grain size distribution analysis for 62 fault core samples cropped from 12 different spots located in the vicinity of Kyongju and Ulsan, Korea. As a result, the range of shear strength representing the characteristics of fault cores in the study regions is determined with regard to vertical stress using a regression analysis for experiment data. The weight ratio of gravels in the samples is proportional to the shear strength and that of silt and clay is in inverse proportion to the shear strength. For most samples, the coefficient of determination is over 0.7 despite of inhomogeneity of them and consequently we determined the lower limit and upper limit of the shear strength with regard to the weight ratio by setting the confidence interval of 95%.

Changes of Head Posture in Standing and Sitting Posture (서 있는 자세와 앉은 자세에서 두부자세의 변화)

  • Sang-Chan Lee;Kyung-Soo Han;Myung-Seok Seo
    • Journal of Oral Medicine and Pain
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    • v.21 no.2
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    • pp.305-315
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    • 1996
  • This study was performed to investigate the changes of head posture according to natural standing or sitting posture. Twenty seven healthy dental students without any signs and symptoms of temporomandibular disorders participated in this study. Cervical resting posture (CRP) of the head in sagittal plane was measured by Cervical-Range-of-Motion $^\textregistered$(CROM, U.S.A.) and lateral cephalograph was taken in natural posture. The items related to angle in cephalograph were the angles of cranial and cervical inclination to true vertical line(VER/NSL, VER/AML), the angles of cervical inclination to nasion-sella line(CVT/NSL, OPT/NSL), the angles of comical inclination to horizontal line(CVT/HOR, OPT/HOR), the angle of cervical lordosis(CVT/OPT). The items related to line measurement were the distance from subocciput to Cl(Dl), Cl to C2(D2), C2 to C3(D3), C3 to C4(D4), the upper(PNS to posterior pharyngeal wall) and the lower(tongue base to posterior pharyngeal wall) pharyngeal space, the distance from nation to mention(Na-Me), and the radius of comical curvature from the first comical vertebra(Cl ) to the fifth cervical vertebra(C5). The data were analyzed with SAS/STAT program. The obtained results were as follows : 1. Most items related to angular measurement showed significant difference between in standing and sitting posture. The angles of CRP, CVT/NSL, OPT/NSL, CVT/HOR, OPT/HOR, and CVT/OPT were high in sitting posture, but the angles of VER/NSL, VER/NSL were low in sitting posture. 2. In vertebral distance, only the distance between C3 and C4 was differed by the posture, which decreased in sitting posture. In sitting posture, the distance from nasion to menton(Na-Me) was longer, but the radius was shorter than in standing posture. 3. Correlationship in angular measurements was almost same in both postures. Ceervical resting posture(CRP) was correlated with VER/NSL, VER\ulcornerNSL was correlated with CRP, CVT/NSL, and OPT/NSL, VER/AML was correlated with CVT/HOR, OPT/HOR, CVT/OPT, and the angle of cervical lordosis(CVT/OPT) was correlated with the radius. 4. Correlationship in linear measurement was observed only in among D3, D4, and radius. And the Na-Me was not correlated with any other items. From this results, The author concluded that the head posture in sitting was mote backward extended than in standing.

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A STUDY ON THE MANDIBULAR ECCENTRIC MOVEMENT OF THE SUBJECTS WITH TMJ CLICK IN HORIZONTAL PLANE (측두악관절 잡음자의 수평면상 하악 편위 운동에 관한 연구)

  • Na, Kyung-Seon;Kang, Dong-Wan
    • The Journal of Korean Academy of Prosthodontics
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    • v.31 no.2
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    • pp.237-248
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    • 1993
  • Although pantograph has been used to investigate whether the determinents of the mandibular movement were possible contributing factors of TMJ click, there was the problems to understand the role of tooth morphology upon the occurrence of click because of using appliance without tooth contacts. There Were advantages to evaluate the effects of tooth morphology upon the mandibular movements, because intraoral tracing device(Functiograph$^{(R)}$) had been obtained maintaining occlusal contact between the upper and lower natural teeth during mandibular movement. The purpose of this study was to record the mandibular eccentric movement quantitatively performed in 20 adult control subjects and 20 adult subjects with TMJ click and to investigate the effects of occlusion upon the occurrence of TMJ click. The obtained results were as follows : 1. The average ICP-P distance was $3.07{\pm}0.73mm$ in subjects with TMJ click, $2.14{\pm}0.85mm$ in control subjects. There was a statistical significance between subjects with TMJ click and control subjects(P<0.001). 2. The average ICP-P distance was $3.07{\pm}1.14mm$ in subjects with TMJ click, $2.61{\pm}0.96mm$ in control subjects. There was a statistical significance between subjects with TMJ click and control subjects(P<0.05). 3. The average distance of right and left lateral movement was not statistically significant between subjects with TMJ click and control subjects. 4. The average lateral displacement from midline during RCP was $0.75{\pm}0.54mm$ subjects with TMJ click, $0.16{\pm}0.17mm$ in control subjects. There was a statistical significance between subjects with TMJ click and control subjects(P<0.001). 5. The average lateral displacement from midline during protrusive movement was $0.88{\pm}0.54mm$ in subjects with TMJ click, $0.20{\pm}0.23mm$ in control subjects. There was a statistical significance between subjects with TMJ click and control subjects(P<0.001). 6. The average angle of right and left lateral movement was $144.2{\pm}20.20^{\circ}$ in subjects with TMJ click, $138.15{\pm}20.09^{\circ}$ in control subjects. There was a statistical significance between subjects with TMJ click and control subjects(P<0.05).

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Analysis on Fluvial Geomorphological Characteristics based on Past and Present Data for River Restoration: An Application to the Miho River and the Naesung River (하천 복원을 위한 과거 및 현재 자료 기반의 하천지형학적 특성 분석: 미호천과 내성천을 중심으로)

  • Lee, Chan Joo;Kim, Ji Sung;Kim, Kyu Ho;Shin, Hyoung Sub
    • Journal of Korea Water Resources Association
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    • v.48 no.3
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    • pp.169-183
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    • 2015
  • As a basic work for river restoration, analysis on fluvial geomorphological characteristics is made using past and present data to understand close-to-nature geomorphic status. The Miho and the Naesung Rivers are targets of this study. Fluvial geomorphic variables including valley-floor width, sinuosity, bankfull width, channel gradient, bed material size, bankfull discharge and unit stream power are evaluated with dominant processes. Though common sand-bed rivers with similar catchment area, the Miho and the Naesung Rivers are different in terms of valley-floor width, channel shape variables and dominant processes related with longitudinal location. In addition, analyses on interrelationship among the geomorphological variables are carried. Bankfull width is shown to be proportional to bankfull discharge, as is in a rough agreement with the previous studies. Relationship of bankfull discharge and channel gradient shows meandering and braiding are prevalent in the Miho River, whereas the most of the sub-reaches of the Naesung River fall to braiding. Relationship of channel gradient with width-depth ratio indicates dune-ripple processes are dominant in the Miho River, while the Naesung River shows longitudinal diversity from braiding in the downstream sub-reaches to riffle-pool and plane-bed along the upper ones. Analyses based on the past data on a river in a close-to-nature status are thought to be rather reasonable in comparison with those on the same river in a engineered condition.

Structural Layers and History of Folding in the Western Part of the Baegunsan Syncline, Samcheog Coalfield, South Korea (백운산향사(白雲山向斜) 서단부(西端部)의 구조계층(構造階層)과 습곡작용(褶曲作用)의 과정(過程))

  • RHI, Jae-Young;PARK, Bong-Soon
    • Economic and Environmental Geology
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    • v.15 no.1
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    • pp.41-47
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    • 1982
  • Typical stratigraphic sequences of Paleozoic form the Baegunsan Syncline (equal to Hambaeg Syncline) and Taebaegsan Group is the basement in the southern part of Kangweon Province. Deformation pattern depends on their stratigraphic site and their internal properties. In the biotite schists and meta-sandstones of Pre-Cambrian sequences, flow folds and ptygmatic folds are developed, and high strain deformation is pervasive. Deformational patterns of Cambro-Ordovician are variable because of their various formations. Fracturing is pervasive in the Jangsan Quartzite and Daegi and Maggol Limestone. Welldeveloped slaty cleavage and angular folds of kink and chevron types are the prevailing structures of pelitic rocks. The most characteristic feature of limestone alternated with argillite is the "Compositional cleavage (Author's proposal)" known as the "Worm-eatern" structures. It was known that this structures have a sedimentary origin. But their preferred orienation of long axis of erosional lime holes, originated from tectonic deformation of folding. And this structures have the same character as the axial plane cleavages. Fracturing and long wave concentric folds are dominant characters of the Upper Paleozic sequences. In this area, two folds are superimposed. Field studying and analysis of structures show that the cross-folds of NS-direction are pervasive and were deformed by the EW-directional Baegunsan Syncline. The cross-folding is the major and penetrative deformation and prior to Baegunsan Syncline.

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Difference in glenoid retroversion between two-dimensional axial computed tomography and three-dimensional reconstructed images

  • Kim, Hyungsuk;Yoo, Chang Hyun;Park, Soo Bin;Song, Hyun Seok
    • Clinics in Shoulder and Elbow
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    • v.23 no.2
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    • pp.71-79
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    • 2020
  • Background: The glenoid version of the shoulder joint correlates with the stability of the glenohumeral joint and the clinical results of total shoulder arthroplasty. We sought to analyze and compare the glenoid version measured by traditional axial two-dimensional (2D) computed tomography (CT) and three-dimensional (3D) reconstructed images at different levels. Methods: A total of 30 cases, including 15 male and 15 female patients, who underwent 3D shoulder CT imaging was randomly selected and matched by sex consecutively at one hospital. The angular difference between the scapular body axis and 2D CT slice axis was measured. The glenoid version was assessed at three levels (midpoint, upper one-third, and center of the lower circle of the glenoid) using Friedman's method in the axial plane with 2D CT images and at the same level of three different transverse planes using a 3D reconstructed image. Results: The mean difference between the scapular body axis on the 3D reconstructed image and the 2D CT slice axis was 38.4°. At the level of the midpoint of the glenoid, the measurements were 1.7°±4.9° on the 2D CT images and -1.8°±4.1° in the 3D reconstructed image. At the level of the center of the lower circle, the measurements were 2.7°±5.2° on the 2D CT images and -0.5°±4.8° in the 3D reconstructed image. A statistically significant difference was found between the 2D CT and 3D reconstructed images at all three levels. Conclusions: The glenoid version is measured differently between axial 2D CT and 3D reconstructed images at three levels. Use of 3D reconstructed imaging can provide a more accurate glenoid version profile relative to 2D CT. The glenoid version is measured differently at different levels.

MANDIBULAR DIFFERENTIAL PREMOLAR EXTRACTI0N IN GROWING PATIENTS (성장기 환자에서 하악의 차등적 소구치 발치)

  • Kim, Do-Hoon;Sung, Sang-Jin;Moon, Yoon-Shik
    • The korean journal of orthodontics
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    • v.31 no.1 s.84
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    • pp.1-13
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    • 2001
  • The extraction lot orthodontic treatment can be adopted for aligning crowded dentition, improving facial esthetics and solving a skeletal discrepancy as alternative for a surgical option. Mandibular second premolar extraction was often selected as treatment plan when there we very little or no space shortage in lower arch or limited retraction of the lower incisors was required. The primary object of this study was evaluate a pretreatment condition and examine the amount of tooth movement ior a mandibular second premolar extraction in growing patients. Pretreatment and posttreatment lateral cephalograms of 14 cases that had their four first premolar extracted (4/4 group), 15 cases with upper first and lower second premolar extraction (4/5 group) were selected. Structural method superimposition was conducted to evaluate a difference of dental change between 4/4 and 4/5 group. The results were as follows, 1. Pretreatment factor for 4/4 extraction or 4/5 extraction choice included maxillary incisor axis to occlusal plane, Class II molar relationship, IMPA and interincisal angle. 2. The amount of molar anterior movement in 4/5 group was greater than that of 4/4 group(p<0.05). 3. There was no significant difference between 4/4 group and 4/5 group in aspects of maxillary tooth movement(p<0.05).

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CRANIOFACIAL MORPHOLOGIC CHARACTERISTICS OF PROFESSIONAL SPORTSMEN (운동이 안면두개골의 형태에 미치는 영향)

  • Lim, Eun-Kyung;Choi, Yeong-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.30 no.4
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    • pp.563-575
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    • 2003
  • The purpose of this study was to investigate differences in craniofacial characteristics of professional sportsmen who have practiced since their prepubertal periods. From the standardized lateral and P-A cephalograms of 137 sportsmen, 7 angular, 19 linear, 4 ratio, and 2 index measurements were measured and evaluated by means of statistical methods. The samples were divided into three groups: Group 1; ice hockey(n=17), foot-ball(n=27), basketball(n=16) Group 2; baseball(n=16), gymnastics(n=13), and Group 3; judo(n=18), ssireum(n=10), weight lift(n=20). The results were as follows: It seemed obvious that the cephalic indices of the 3 groups exhibited brachycephalic headform (Group 1; $0.85{\pm}0.04$, Group 2; $0.84{\pm}0.04$, Group 3; $0.83{\pm}0.06$) and there was no statistical difference among the groups (p>0.05). The facial indices of the Group 1 ($0.93{\pm}0.05$) and Group 2 ($0.93{\pm}0.04$) exhibited definite leptoprosopic facial forms while the Group 3 ($0.90{\pm}0.04$) showed more or less euryprosopic facial form, and there appeared significant difference between the Group 1 and 3 (p<0.05), and also between the Group 2 and 3 (p<0.05). There appeared strong relationships between the facial indices and the facial axis angle, mandibular plane angle, total craniofacial height, total facial height, upper anterior dental height, lower anterior dental height, mandibular length, lower anterior facial height ratio, and especially with lower anterior facial height (p<0.001). It seemed that most of the vertical facial measurements of the Group 1 and 2 appeared to be larger than those of the Group 3.

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