• Journal of the Korean earth science society
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• v.30 no.5
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• pp.565-580
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• 2009

The Yongdong basin developed during Early Cretaceous in the central part of the Korean Peninsula and bounded on the northwest and southeast by northeast trending mega-scale strike-slip Yongdong Fault. An 8 km thick succession of exclusively terrigeneous sediments can be grouped into two mega-sequences. In concert with the migration of depocenter, the upper sequence overlaps the lower and occupies northern part of the basin during basin evolution. Alluvial and lacustrine environments were predominantly formed from early to late stage of the basin formation. Several lines of evidence support that the basin was formed within intra-arc tectonic environments and destroyed by polyphase tectonic force. Schematic evolutionary diagram of the basin is proposed.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.67-74
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• 2019

Purpose: The purpose is to correct for position errors caused by long treatment times. By correcting the target motion that can occur during lung SBRT using IntraFraction CBCT. Methods and materials: We analyzed retrospectively the IFM data of 14 patients with two treatment arc in the treatment plan for lung cancer with stereotactic radiotherapy. An IntraFraction Motion was applied to the Arccheck phantom to acquire the Gamma index data. Results : IntraFraction Motion during the first treatment arc is in the left-right(LR), superiorinferior(SI), anterior-posterior(AP) directions were $0.16{\pm}0.05cm$, 0.72 cm(max error), $0.2{\pm}0.14cm$, 1.26 cm, $0.24{\pm}0.08cm$, 0.82 cm and rotational directions was $0.84{\pm}0.23^{\circ}$, $2.8^{\circ}$(pitch), $0.72{\pm}0.23^{\circ}$, $2.5^{\circ}$(yaw), $0.7{\pm}0.19^{\circ}$, $2^{\circ}$(roll). IntraFraction Motion during the second treatment arc is in the LR, SI, AP directions were $0.1{\pm}0.04cm$, 0.37 cm, $0.14{\pm}0.17cm$, 2 cm, $0.12{\pm}0.04cm$, 0.5 cm and rotational directions was $0.45{\pm}0.12^{\circ}$, $1.3^{\circ}$, $0.37{\pm}0.1^{\circ}$, $1^{\circ}$, $0.35{\pm}0.1^{\circ}$, $1.2^{\circ}$. Gamma index pass rates were $82.64{\pm}10.51%$, 48.4 %. Conclusions : In this study, we examined the validity of IntraFraction Motion correction in lung SBRT and the efficiency of IntraFraction CBCT. Due to the nature of SBRT treatment, IFM may increase due to the increased treatment time. It is believed that the increase in IFM with the increase in treatment time can be improved with the use of FFF Beam and additional position correction using CBCT during treatment.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.247-256
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• 2014

Purpose : To assess target motion during radiotherapy by quantifying daily setup errors and inter-fractional and intra-fractional movements of pancreatic fiducials. Materials and Methods : Eleven patients were treated via stereotactic body radiotherapy (SBRT) with volumetric modulated arc therapy. Bony setup errors were calculated using cone beam computed tomography (CBCT). Inter-fractional and intrafractional fiducial (seed) motion was determined via cone beam computed tomography (CBCT) projections and orthogonal fluoroscopy. Results : Using an off-line correction protocol, setup errors were 0.0 (-1.7-4.0), 0.3 (-0.5-3.0), and 0.0 (-4.1-6.6) mm for the left-right, anterior-posterior, and superior-inferior directions respectively. Random inter-fractional setup errors in the mean fiducial positions were -0.1, -1.1, and -2.3 mm respectively. Intra-fractional fiducial margins were 9.9, 7.8, and 12.5 mm, respectively. Conclusion : Online inter-fractional and intra-fractional corrections based on daily kV images and CBCT expedites SBRT of pancreatic cancer. Importantly, inter-fractional and intra-fractional motion needs to be measured regularly during treatment of pancreatic cancer to account for variations in patient respiration.

• Clinics in Shoulder and Elbow
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• v.23 no.2
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• pp.94-99
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• 2020

Background: Intra-articular distal humeral fractures can be surgically challenging. It remains under discussion whether open reduction and internal fixation (ORIF) or total elbow arthroplasty (TEA) is more beneficial for treatment of the elderly. This study aimed to compare the clinical and functional outcomes of ORIF and TEA for managing intra-articular distal humerus fractures in patients aged 65 years or older. Methods: Patients who underwent ORIF (n=28) or TEA (n=43) for in intra-articular distal humerus fracture between May 2008 and December 2018 were reviewed. Range of motion, Mayo Elbow Performance Score (MEPS), Disabilities of the Arm, Shoulder, and Hand (DASH) score, radiologic outcomes, and surgical complications were evaluated at the final follow-up visit. Results: The ORIF and TEA groups showed a mean arc of flexion-extension of 97°±21° and 101°±12°, respectively. The mean MEPS and DASH scores were 94±15 and 27±12 points, respectively, in the ORIF group and 81±27 and 47±28 points in the TEA group. This difference was statistically significant. The incidence of total complications was similar between the groups. Conclusions: In patients older than 65 years with intra-articular distal humerus fracture, ORIF had better outcomes than TEA.

• 한국해양학회지
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• v.25 no.2
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• pp.74-83
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• 1990

The similarity in Mesozoic geology between the Antarctic Peninsula and South America indicates the possibility that they had situated along the same tectonics line before the separation of southwestern Gondwanaland. The igneous activity around the Antarctic Peninsula, including the South Shetland islands, can be correlated with the South American Cordillera Orogeny due to the subduction of Farallon/Phoenix plate until late Mesozoic. However igneous activity in Tertiary correlates with the tectonics movement accompanying the formations of Drake passage and Scotian sea. The south Shetland islands form a Jurassic-Quaternary miasmatic island arc on the sialic basement of schist and deformed sedimentary rocks. Forming of the South Shetland Islands arc began during the latest Jurassic or earliest Cretaceous from the southwestern part of the archipelago. The igneous activity migrated northeasterly and continued in most areas until late Tertiary. The entire arc-forming period, between late Jurassic and late tertiary times, was characterized by emplacement and eruption of magmas of intermediate between island-arc tholeiite and calc-alkaline types. However, Quaternary volcanic rocks show strong alkaline affinities which corresponds to the switch from compressional to intra: plate tensional tectonics. The rocks of late Cretaceous to Tertiary, mainly found in King George Island, consist of lava of basalt to andesite and intercalated pyroclastic rocks. Some of the volcanic rocks, which ofter called quartz-pyrite lodes'are severely altered and include much content of calcite,silica and pyrite.The stratographic succession of King George Island can be divided into two formation:Fields formation and Hennequin formation.The Fildes formation crops out at the west side of Admiralty Bay n King George Island,while the Hennequin formation at the east side of the bay.These two formtions are thought to be formed contempiranceously.The Fildes formation consists of altered olivine-basalt and basaltic andestie, whereas the Hennequin formation consists of fine-grained hypersthene-augite-andesite.Both formations interclate pyroclastic rocks.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.4
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• pp.549-563
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• 2008

The purpose of this research is to identify the urban structure in Korea. Though there is research regarding urbanization, there is little regarding the urban structure of the Korean economy. In this paper, two issues will be discussed: the measurements of inter-city and intra-city structure in Korean Metropolitan Statistical Areas (MSAs), which is newly defined. First, the city size rank rule, widely known as Zipf’s Law, will illustrate Korean the inter-city structure. The city size rank rule gives an idea whether Korean MSAs are balanced or not. In general, Korea has a heavy concentration in the Seoul MSA in terms of population. It could be either that the Seoul MSA is too big or that the Busan MSA is too small or both. If this is the primacy problem, a decentralization policy is necessary. On the other hand, if it is a second city problem, development policies for the Busan MSA and Daegu MSA are more important. Next, the Korean intra-city structure will be discussed. The evolutions of the MSAs explain intra-city structure by analyzing population density function and the housing price function. Some large MSAs such as Seoul and Busan have experienced urban sprawl, while other MSAs have experienced urban concentration. The population density gradient by the distance from the ARC GIS shows the growth rate of a city. According to the Spatial Mismatch Index between population and employment, the Ulsan MSA, Gwangju MSA, and Suwon-Hwaseong-Osan MSA are more mismatched, while the Daejeon MSA and Incheon MSA are less mismatched. Therefore, these analyses of Korean urban structure are meaningful in developing regional policy.

• Clinics in Shoulder and Elbow
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• v.15 no.2
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• pp.130-137
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• 2012

Purpose: To evaluate and report the clinical outcome after surgical treatment of intra-articular comminuted fracture of distal humerus in the elderly with osteoporosis. Materials and Methods: From January 2007 to October 2009, 24 patients aged older than 65 years with intra-articular comminuted fracture of distal humerus underwent surgical treatment. 18 patients (Group I) were managed using primary open reduction and internal fixation (OR IF) through the modified posterior approach and 6 patients (Group II) were taken primary total elbow arthroplasty. The average follow up period was 17.2 months. According to the AO classification, there were 8 C2, 16 C3 type fractures. All enrolled patients were evaluated radiographically and clinically. Clinical outcomes were assessed with the Mayo Elbow Performance, Disabilities of Arm and Shoulder and Hand, and Musculoskeletal Functional Assessment functional questionnaires. Results: The bony union was observed in 18 patients in group I at average 14 weeks. There were 2 patients with neurapraxia of whom the ulnar nerve symptom did not improve despite of anterior transposition. And non-union at osteotomy sites was seen in 2 patients. The mean Mayo Elbow Performance score was 87.0. The mean DASH score was 32.4. The average arc of elbow flexion was $121.0^{\circ}$ (range, $95{\sim}145^{\circ}$) with mean flexion-contracture of $12.0^{\circ}$ (range, 0 to 35). 6 patients in Group II showed no complication during follow up periods. The mean Mayo Elbow Performance score was 89.1. The mean DASH score was 44.3. The average arc of elbow flexion was $125.1^{\circ}$ (range, $100{\sim}145^{\circ}$) with mean flexion-contracture of $12.6^{\circ}$ (range, 0 to 30). Conclusions: With careful patient selection, Total elbow arthroplasty as well as OR IF could achieve good outcomes in elderly of comminuted intra-articular distal humerus fracture with osteoporosis.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.45-52
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• 2015

Purpose : The dose distribution of organ at risk (OAR) and normal tissue is affected by treatment technique in postoperative radiation therapy for prostate cancer. The aim of this study was to compare dose distribution characteristic and to evaluate treatment efficiency by devising VMAT plans according to applying differed number of arc and IMRT plan for postoperative patient of prostate cancer radiation therapy using a rectal balloon. Materials and Methods : Ten patients who received postoperative prostate radiation therapy in our hospital were compared. CT images of patients who inserted rectal balloon were acquired with 3 mm thickness and 10 MV energy of HD120MLC equipped Truebeam STx (Varian, Palo Alto, USA) was applied by using Eclipse (Version 11.0, Varian, Palo Alto, USA). 1 Arc, 2 Arc VMAT plans and 7-field IMRT plan were devised for each patient and same values were applied for dose volume constraint and plan normalization. To evaluate these plans, PTV coverage, conformity index (CI) and homogeneity index (HI) were compared and $R_{50%}$ was calculated to assess low dose spillage as per treatment plan. $D_{25%}$ of rectum and bladder Dmean were compared on OAR. And to evaluate the treatment efficiency, total monitor units(MU) and delivery time were considered. Each assessed result was analyzed by average value of 10 patients. Additionally, portal dosimetry was carried out for accuracy verification of beam delivery. Results : There was no significant difference on PTV coverage and HI among 3 plans. Especially CI and $R_{50%}$ on 7F-IMRT were the highest as 1.230, 3.991 respectively(p=0.00). Rectum $D_{25%}$ was similar between 1A-VMAT and 2A-VMAT. But approximately 7% higher value was observed on 7F-IMRT compare to the others(p=0.02) and bladder Dmean were similar among the all plan(P>0.05). Total MU were 494.7, 479.7, 757.9 respectively(P=0.00) for 1A-VMAT, 2A-VMAT, 7F-IMRT and at the most on 7F-IMRT. The delivery time were 65.2sec, 133.1sec, 145.5sec respectively(p=0.00). The obvious shortest time was observed on 1A-VMAT. All plans indicated over 99.5%(p=0.00) of gamma pass rate (2 mm, 2%) in portal dosimetry quality assurance. Conclusion : As a result of study, postoperative prostate cancer radiation therapy for patient using a rectal balloon, there was no significant difference of PTV coverage but 1A-VMAT and 2A-VMAT were more efficient for dose reduction of normal tissue and OARs. Between VMAT plans. $R_{50%}$ and MU were little lower in 2A-VMAT but 1A-VMAT has the shortest delivery time. So it is regarded to be an effective plan and it can reduce intra-fractional motion of patient also.

• Clinics in Shoulder and Elbow
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• v.16 no.1
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• pp.33-39
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• 2013

Purpose: The aim of this study is to evaluate the clinical result of intra-articular fractures of the distal humerus (AO type C) in elderly osteoporotic patients treated with double tension band osteosynthesis. Materials and Methods: From January 2006 to December 2010, 10 elderly osteoporotic patients(1 male, 9 females) with intra-articular fractures of the distal humerus (AO type C) were treated with double tension band osteosynthesis. The mean age of patients at the time of surgery was 74.6(66~84) years and the mean follow-up period was 39.2(20~74) months. The fracture union and complications were assessed and the functional result was evaluated by the rating system of Jupiter et al. and the Mayo elbow performance index. Results: Bone union was achieved in all patients with no secondary displacement. The mean time for union was 16.6(13~22) weeks. The average postoperative arc of elbow flexion was 119(100~140) degrees with a mean flexion contracture of 8.5(0~15) degrees. The recovery in two patients was rated as excellent, in 7 as good, and in 1 as fair in terms of the Mayo elbow performance index with average value of 82(70~90) points. Seven patients were rated as excellent, 1 as good, and 2 as fair in terms of the rating system of Jupiter et al. Changing tension band wiring was performed in one patient as skin irritation was noticed due to tension band knots. Heterotopic ossification developed in one patient but had no symptom. Conclusion: Double tension band osteosynthesis in intra-articular fractures of distal humerus (AO type C) in elderly osteoporotic patients can provide sufficient and secure stability to allow early rehabilitation.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.235-243
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• 2002

Ni-base superalloys are used extensively in industry, both in aeroengines and land based turbines. About 60% by weight of most modern gas turbine engine structural components are made of Ni-base superalloys. To satisfy practical demands, the efficiency of gas turbine engines has been steadily and systematically increased by design modifications to handle higher turbine inlet or firing temperatures. However, the increase in operating temperatures has lead to a decrease in the life of components and increase in costs of replacement. Moreover, around 80% of the large frame size industrial/utility gas turbines operating in the world today were installed in the mid-sixties to early seventies and are now 25 to 30 years old. Consequently, there are greater opportunities now to repair and refurbish the older models. Basically, there are two major factors influencing the weldability of the cast alloys: strain-age cracking and liquation cracking. Susceptibility to strain-age cracking is due to the total Ti plus AI content of the alloy; Liquation cracking is due either to the presence of low melting constituents or constitutional liquation of constituents. Though Rene 41 superalloy has 4.5wt.% total Ti and Al content and falls just below the safe limit proposed by Prager et al., controlled grain size and special heat treatments are needed to obtain crack-free welds. Varying heat treatments and filler materials were used in a laboratory study, then the actual welding of service parts was carried out to verity the possibility of crack-tree weld of components fabricated from Rene 41 superalloy. The microstructural observations indicated that there were two kinds of carbides in the FCC matrix. MC carbides were located along the grain boundaries, while M$_{23}$C$_{6}$ carbide was located both inter and intra granularly. Two kinds of filler materials, Rene 41 and Hastelloy X were used to gas tungsten arc weld a patch into the sheet metal, along with varying pre-weld heat treatments. The microstructure, hardness and tensile tests were determined. The service distressed parts were categorized into three classes: with large cracks, with medium cracks and with small or no visible cracks. No significant difference in microstructure among the specimens was observed. Specimens were cut from the corner and the straight edge of the patch repair, away from the corner. The only cracks present were found to be associated with inadequate surface preparation to remove oxidation. Guidelines for oxide removal and the welding procedures developed in the research enabled crack-free welds to be produced.d.