• Radiation Oncology Journal
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• v.3 no.2
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• pp.145-151
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• 1985

The peripheral dose distributions of wedge fields of Co-60 $\gamma-ray$ and 1 OMV x-ray were measured by the solid state detector controlled by means of semiautomatic water phentom system. The measurements were made on the principal plane parallel to the cross section of wedge filter (blade and ridge direction). For parallel motion of the detector to the beam axis the distance from the margin of radiation field at suface were 3, 5 and 10cm. For tranverse motion the depth of measurement were dm, 5, 10 and 15cm. The followings were drawn from the measurement. 1. The peripheral dose of the blade side of wedges was generally higher than that of the ridge side at symmetric point about beam axis. 2. In the superficial region phenomena of dose build-up appeared. 3. For Co-60 $\gamma-ray$ field, the peripheral dose did not monotonously decrease with the distance from the field margin but increase in some range, consequently showing a peak dose. 4. The peripheral dose did not only depend on radiation quality and field size, but also on wedge angle and wedge direction.

• Journal of the Korean earth science society
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• v.23 no.8
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• pp.697-706
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• 2002

Authigenic siderite grains, ranging 100 to 250-${\mu}$m in diameter, are abundant in an about 8,600-year-old sediment layer in Namyang Bay, west coast of Korea. The siderites exhibit the aggregated spherulitic morphology with well-developed rhombs on the grain surfaces. They consist mostly of FeCO$_3$ (average, 65%) and MnCO$_3$ (average, 22%) with low Mg/Ca ratio (less than 0.4) in their bulk composition. A series of compositional ternary discrimination diagrams, together with high Mn and low Mg contents, show that only meteoric porewater was involved in siderite precipitation, assuming that depositional environment of host sediment is an organic-rich freshwater system. Considering a series of results such as radiocarbon age, authigenic Mn-rich siderite and lithological features, siderite-hosting sediment (unit Tl) is interpreted as freshwater swamp or bog deposition, infilling the topographic depressions that locally existed before the formation of mid-to-late Holocene tidal deposits. Center-to-margin compositional variation within individual grain is very systematic; Mn and Ca decrease towards the margin of a siderite grain, while Fe and Mg increase. It suggests that the spherulitic siderites were precipitated in this sedimentary layer in a series during the early diagenesis of MnOx-FeOx reduction under steady-state.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.79-86
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• 2015

Purpose : The purpose of this study was to determine the proper treatment time of stereotactic body radiation therapy for spine metastasis cancer by using the image guidance system of CyberKnife(Accuray Incorporated, USA) which is able to correct movements of patients during the treatment. Materials and Methods : Fifty seven spine metastasis cancer patients who have stereotactic body radiation therapy of CyberKnife participate, 8 of them with cervical spine cancer, 26 of them with thoracic spine cancer, and 23 of them with lumbar spine cancer. X-ray images acquired during the treatment were classified by treatment site. From the starting point of treatment, motion tendency of patients is analyzed in each section which is divided into every 5 minutes. Results : In case of cervical spine, there is sudden increase of variation in 15 minutes after the treatment starts in rotational direction. In case of thoracic spine, there is no significantly variable section. However, variation increases gradually with the passage of time so that it is assumed that noticeable value comes up in approximately 40 minutes. In case of lumbar spine, sharp increase of variation is seen in 20 minutes in translational and rotational direction. Conclusion : Without having corrections during the treatment, proper treatment time is considered as less than 15 minutes for cervical spine, 40 minutes for thoracic spine, and 20 minutes for lumbar spine. If treatment time is longer than these duration, additional patient alignments are required or PTV margin should be enlarged.

• Journal of the Korean earth science society
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• v.32 no.6
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• pp.640-653
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• 2011

We simulate the propagation of earthquake waves in the continental margin of Antarctica using the elastic wave modeling algorithm, which is modified to be suitable for acoustic-elastic coupled media and earthquake source. To simulate the various types of earthquake source, the staggered-grid finite-difference method, which is composed of velocity-stress formulae, can be more appropriate to use than the conventional, displacement-based, finite-difference method. We simulate the elastic wave propagation generated by earthquakes combining 3D staggered-grid finite-difference algorithm composed of displacement-velocity-stress formulae with double couple mechanisms for earthquake source. Through numerical tests for left-lateral strike-slip fault, normal fault and reverse fault, we could confirm that the first arrival of P waves at the surface is in a good agreement with the theoretically-predicted results based on the focal mechanism of an earthquake. Numerical results for a model made after the subduction zone in the continental margin of Antarctica showed that earthquake waves, generated by the reverse fault and propagating through the continental crust, the oceanic crust and the ocean, are accurately described.

• Journal of the Korean Arthroscopy Society
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• v.11 no.1
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• pp.1-6
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• 2007

Purpose: The purpose of this preliminary report is to investigate the short term outcome of performing gel type fibrin matrix autologous chondrocyte implantation to patients who have damaged knee joint cartilage using secondary arthroscopy. Material and Methods: Six patients who have damaged knee joint cartilage were involved. The average size of defect was $5.13\;cm^2$. While performing primary arthroscopy, whole layer of cartilage bone was obtained either from the margin of damaged cartilage or the bilateral margin of a trochlea. The cartilaginous cells were obtained for culture for four to six weeks. While performing secondary minimal invasive arthrotomy, gel type fibrin matrix autologous chondrocyte was implanted on the chondral defect site. Results: 4 among 6 patients to be more than good in Modified Cincinnati Knee Scoring system. Lysholm function score was 59.5 preoperatively, and it improved to 76.25. ICRS grading by performing secondary arthroscopy revealed 4 out of 6 patients to be nearly normal. Conclusion: Gel type fibrin matrix autologous chondrocyte implantation is a treatment for cartilage defect, which takes less time to operate than the conventional implantation. In addition, this method minimizes the size of incision and allows arthroscopic surgery. However, long term follow up and more case study is thought to be necessary.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.5
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• pp.535-543
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• 2004

Purpose: The purpose of this study is to compare the effect of two fiber post systems and one metal cast post system on the fracture strength and fracture pattern of crowned, endodontically treated teeth with 2 mm-height of the reamining tooth structure. Materials and methods: A total of 36 recently extracted sound human mandibular premolars were selected Each tooth structure of the crown portion except 2mm-height of the one above the cementoenamel junction was removed. After being endodontically treated, they were randomly distributed into 3 groups: group 1, restored with quarts fiber post(D.T. Light-Post), group 2, with glass fiber post(FRC Postec), and group 3, metal cast post and core. All teeth were fully covered with nonprecious metal crowns. Each specimen was embedded in an acrylic resin block and then secured in a universal load-testing machine. A compressive load was applied at a 130 degree angle to the long axis of the tooth until fractured, at a crosshead speed 20mm/min. The highest fracture loads were measured and recorded as the fracture strength of each specimen. Fracture areas were measured on the mid-buccal and mid-lingual point from the crown margins. One-way analysis of variance and Turkey test were used to determine the statistic significance of the different fracture loads and areas among the groups (p<0.05). Results: The mean fracture loads were $1391{\pm}$425N(group 1), $1458{\pm}476N$(group 2) and $1301{\pm}319N$(group 3). The fracture loads among the three groups had no statistically signifiant difference (p>.05). The mean fracture area of the fiber post was closer to the crown margin than that of the metal cast post and core(p<.05). The metal cast post showed unrestorable and catastrophic fracture patterns. Conclusion: Within the limitations of this study, fracture loads with any statistically significant difference were not recorded for endodontically treated teeth restored with two fiber posts and the metal cast post. But teeth restored with the fiber posts typically showed the fracture pattern close to the crown margin, which was almost restorable.

• Economic and Environmental Geology
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• v.35 no.1
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• pp.75-95
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• 2002

The Andong pluton in the Andong Batholith is composed of comagmatic plutonic rocks, in which the lithofacies comprise hornblende biotite tonalite in the central paft biotite granodiorite in the marginal paft and porphyritic biotite granite at the topside (noJthea~tern paft) of the pluton. The pluton is petrographically and petrochemically zoned, having more mafic center than margin and topside. Distribution pallern of the lithofacies represents a reverse zoning in the pluton. Modal and chemical data in the pluton show progressive and gradual compositional variations from the centrer via the margin to the topside. Quartz and K-teldspar increase toward the topside of the pluton, whereas hornblende, biotite and color index increase toward the center. The bulk composition in the pluton is also reversely zoned, with high $Si0_2$ and $K_{2}O$ in the topside facies, and high MnO, CaO, $Ti0_2$, $Fe_{2}O_{3}$t, MgO and $P_{2}O_{5}$ in the central facies. The reverse zoning is also evident in higher Cr. V, Ni, Sc and Sr of the more mafic tonalite in the interior. The reversely zoned pluton results from remobilization (resurgence) of the lower more mafic compositional zone into the upper more felsic zones of the pluton modified by thennogravitational diffusion and fractional crystallization. In the initial stages of evolution, the pluton was a petrochemical system that fonned chemical compositional zonation with mafic tonalitic magma in the lower. granodioritic one in the middle and granitic one in the upper paft of the magma chamber. Periodic influxes of more mafic magma from the ba~e resulted in mingling of liquids and redistribution of minerals, and may have triggered the remobilil.ation of the lower compositional zone into the upper more felsic zones.

• Economic and Environmental Geology
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• v.50 no.6
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• pp.525-535
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• 2017

Exhumation mechanism of migmatite in orogenic belts provides insights into thermo-mechanical evolution of lithosphere in association with orogeny. This study deals with kinematics of structures in and around the Gwangcheon Gneiss, as a preliminary study on exhumation mechanism, which is a main constituent of a domal structure (viz., Oseosan Dome) in the Hongseong area, southwestern margin of the Gyeonggi massif. Geological structures in the Gwangcheon Gneiss, which mainly comprises southern and northwestern part of the Oseosan Dome, generally have kinematic component of top-outward shear. This feature is likely to represent diapiric dome-up movement. In addition, a high strain zone, by which the tectonic domain involving the Gwangcheon Gneiss is bounded on the west, show structural features with normal sense of shear component. Taking available (thermo)chronological data into account, it is interpreted that activation of the high strain zone and exhumation of the Gwangcheon Gneiss occurred during Late Triassic, when the Gyeonggi massif was widely affected by post-collisional processes. It means that the Gwangcheon Gneiss was diapirically moved up and exhumed in the footwall of extensional high strain zone in association with Triassic post-collisional processes.

• Clinics in Shoulder and Elbow
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• v.19 no.3
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• pp.125-129
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• 2016

Background: Superior migration of humeral head has been conventionally determined by measuring the acromiohumeral distance (AHD), We sought to devise a novel measurement system more reliably and accurately than AHD. We described a structural landmark called 'C-line'. In this study, we investigated the clinical usefulness of 'step-off of the C-line (SOC)' compared to that of AHD. Methods: The C-line formed from the medial margin of the proximal humeral head continuing up to the inferior margin of the articular glenoid and then to the lateral border of the scapula. The superior migration of the humeral head triggered by a rotator cuff tear introduces a discontinuity in this C-line. We measured the distance of this discontinuity. We enrolled 144 patients who underwent a rotator cuff repair. We selected 58 controls who didn't have any cuff lesions apparent on magnetic resonance imaging. Using radiographs derived from standardized true anteroposterior views of the shoulder, we measured the SOC and the AHD. We used t-tests for statistical analyses. Results: A rotator cuff tear was associated with an increase in SOC and a decrease in AHD. In control group, the mean SOC was $1.29{\pm}1.71mm$ and AHD was $9.71{\pm}2.65mm$. In cuff tear group, the mean SOC was $3.15{\pm}3.41mm$ and AHD was $8.28{\pm}1.76mm$. The mean SOCs of the patient group in relation to the mean SOC of the control group according to tear size, the SOCs of medium tear and lager groups showed statistically significant increase (p<0.05). Conclusions: The SOC may be a similarly effective to diagnose cuff tears of medium size and larger compared with AHD.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.57-68
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• 2002

The purpose of this study was to evaluate microleakage of etched and non-etched amalgam restorations lined with dentin bonding system primer and adhesives. Class V amalgam preparations were made in 100 extracted human premolars divided into 10 groups with 10 teeth each. SEM was taken to assess the dentin/amalgam interface. The results were as follows; 1. At the occlusal and gingival margins, all experimental groups showed lower leakage value than unlined group(p<0.05) The $Copalite^{(R)}-lined$ group showed higher leakage value than other experimental groups(p<0.05). 2. In all experimental groups, the gingival margin showed higher leakage value than the occlusal margin. 3. There were no significant difference between non-etching and etching groups, primer only and primer & adhesive groups, primer & adhesive and self-priming adhesive groups(p>0.05). 4. On the SEM observation, continuous gaps were observed in the unlined and $Copalite^{(R)}-lined$ groups, but the gaps were filled with primer or adhesive layer in other experimental groups.