• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1194-1202
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• 2002

A study on the topology optimization of a multi-spectral camera for space-use is presented. The optimization is carried out under self-weight and polishing pressure loading. A multi-spectral camera for space-use experiences degradation of optical image in the space, which can not be detected on the optical test bench on the earth. An optical surface deformation of a primary mirror, which is a principal component of the camera system, is an important factor affecting the optical performance of the whole camera system. In this study, topology optimization of the primary mirror of the camera is presented. As an objective function, a measure of Strehl ratio is used. Total mass of the primary mirror is given as a constraint to the optimization problem. The sensitivities of the objective function and constraint are calculated by direct differentiation method. Optimization procedure is carried out by an optimality criteria method. For the light-weight primary mirror design, a three dimensional model is treated. As a preliminary example, topology optimization considering a self-weight loading is treated. In the second example, the polishing pressure is also included as a loading in the topology optimization of the mirror. Results of the optimized design topology for the mirror with various mass constraints are presented.

• The Journal of the Acoustical Society of Korea
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• v.22 no.4
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• pp.250-260
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• 2003

Since a bubble in water is a highly nonlinear acoustic scatterer, the acoustic scattered waves from underwater bubbles show highly nonlinear acoustic properties. These acoustic scattered waves can be observed at the second or higher harmonics as well as at the fundamental primary frequency of incident acoustic wave. When two primary acoustic waves of different frequencies are incident on a bubble, the acoustic scattered waves can be also observed at the sum and the difference frequencies of the primary waves. In this study, when the two primary acoustic waves were incident on a bubble screen in water, we observed that the amplitude of difference frequency wave was amplified by the bubble nonlinearity and its directivity was oriented in the propagation directions of primary waves. The directivity of scattered difference frequency wave was analyzed as a coherent scattering for virtual source by using the directivity of the primary acoustic wave.

• Journal of Gastric Cancer
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• v.17 no.2
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• pp.180-185
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• 2017

Despite the decreasing incidence and mortality from gastric cancer, it remains a major health problem worldwide. Ninety percent of cases are adenocarcinomas. Here, we report a case of gastric adenocarcinoma developed after successful treatment of prior primary gastric diffuse large B-cell lymphoma (DLBCL). Our patient was an elderly man with primary gastric DLBCL in whom complete remission was achieved after R-CHOP (cyclophosphamide, adriamycin, vincristine, prednisolone plus rituximab) chemotherapy. Helicobacter pylori infection persisted despite adequate treatment leading to sustained chronic gastritis. The mean time to diagnose metachronous gastric carcinoma was seven years. We believe that a combination of many risk factors, of which chronic H. pylori infection the most important, led to the development of gastric carcinoma following primary gastric lymphoma. In summary, patients who have been successfully treated for primary gastric lymphoma should be followed up at regular short intervals. H. pylori infection should be diagnosed promptly and treated aggressively.

• Journal of Astronomy and Space Sciences
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• v.31 no.3
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• pp.199-204
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• 2014

This paper intends to highlight the effect of the third-body in an inclined orbit on a spacecraft orbiting the primary mass. To achieve this goal, a new origin of coordinate is introduced in the primary and the X-axis toward the node of the spacecraft. The disturbing function is expanded up to the second order using Legendre polynomials. A double-averaged analytical model is exploited to produce the evolutions of mean orbital elements as smooth curves.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.103-114
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• 2016

PURPOSE: The purpose of this study was first to develop a Korean version of pediatric functional muscle testing for children with a motor developmental disorder who have a communication problem and who are aged below five years, and also to verify the content validity. METHODS: First, the preliminary study was conducted to verify the reliability of pediatric functional muscle testing, developed by Venita in Korea. Based on the results of the study, the primary evaluation items were selected and modified. Second, the first test of content validity was conducted through a panel discussion, and a second investigation of content validity was carried out by utilizing the Item Content Validity Index (I-CVI). In this study, we selected only 0.78 or more items from I-CVI. RESULTS: Based on the results of the preliminary study, 19 primary evaluation items were selected. Based on the results of the first and second content validity tests, 15 tertiary evaluation items for the Korean version of pediatric functional muscle testing were determined. CONCLUSION: This study developed a new Korean version of pediatric functional muscle testing and suggested that it will be a useful tool to measure muscle strength for Korean children with a motor developmental disorder and a communication problem, aged below five years.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1145-1148
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• 2014

Background: Single pegylated liposomal doxorubicin (PLD) is commonly used as a salvage treatment in platinum-resistant ovarian cancer, fallopian tube cancer and primary peritoneal adenocarcinoma (PPA) with a satisfactory outcome. However, the data for second generation PLD administered in this setting are still limited. We conducted a retrospective study to evaluate the outcome of patients who received single-agent second generation PLD (LIPO-DOX) after the development of clinical platinum resistance. The study period was between March 2008 and March 2013. LIPO-DOX was administered intravenously 40 $mg/m^2$ every 28 days until disease progression, but for not more than six cycles. The response rate was evaluated using the Gynecologic Cancer Intergroup (GCIG) criteria while the toxicity was evaluated according to WHO criteria. Twenty-nine patients met the inclusion criteria in the study period with an overall response rate of 13.8%. The median progression free survival and overall survival were three and eleven months, respectively. With the total of 96 cycles of chemotherapy, the patients developed grades 3 and 4 hematologic toxicity as follows: anemia, 0%, leukopenia, 9.6%, neutropenia, 32.3% and thrombocytopenia, 0%. In conclusion, the single agent second generation PLD demonstrated modest efficacy in patients with platinum-resistant ovarian cancer, fallopian tube cancer and PPA without serious toxicity.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9831-9834
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• 2014

Background: The prevalence of esophageal cancer (EC) with second primary cancers (SPC) is increasing worldwide. This study was aimed to understand the clinical features of EC patients with SPC in the Taiwanese population. Materials and Methods: Clinical and laboratory data for 180 EC patients with or without SPC were collected between January 2009 and December 2013. Information on treatment approaches, location of SPCs and ABO blood type were also collected and stratified. Results: The most common SPC in EC patients was hypopharyngeal cancer, followed by laryngeal cancer and hepatocellular carcinoma in our study. Malignancies of colon, prostate and lung were also found. There was a significant higher portion of blood type A in the EC patients with SPC compared with those without (42.4% vs 19.5%, P=0.006). Conclusions: The frequency and SPC site distribution and blood type A should be considered in clinical evaluation of EC patients with a high risk of developing SPC in the Taiwanese population.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.1
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• pp.69-79
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• 2021

The purpose of this study was to compare what meanings of earth science pre-service teachers and primary pre-service teachers about science books and reading through science disciplinary reading and how their thoughts on science education are reflected in the science disciplinary reading process. For the study, 24 third-year students majoring in earth science education and 25 second-year students majoring in primary education were selected as subjects for the study at a teacher training college located in the central part of Korea. As a result of the study, first, earth science pre-service teachers used disciplinary reading a lot to acquire knowledge of science content, but primary pre-service teachers used it for the purpose of using it in class, scientific interest, and curiosity solution. Second, earth science pre-service teachers and primary pre-service teachers showed differences in their thinking in using science related books for science education. While earth science pre-service teachers rarely described the use of science books in their classes, primary pre-service teachers actively described science classes. Third, from the perspective of science disciplinary reading, primary pre-service teachers were more actively emphasizing the meaning of disciplinary reading compared to earth science pre-service teachers. In light of the research results that the reading activity in science has a lot of effect, it is thought that a wide range of research on science disciplinary reading should be conducted as a teaching strategy in school field classes.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.263-271
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• 2003

The purpose of the present study was to evaluate the patterns of hybrid layer according to the application time and the frequency and its effects on the shear bonding strength of All-In-One system in primary teeth. A single bonding agent(Scotchbond Multi-Purpose Plus, 3M) and an All-In-One system(Prompt L-pop, 3M ESPE) were applied on the dentin varying the application time and the frequency in primary teeth. Shear bond strength was measured and the patterns of hybrid layers were observed by SEM. The following results were obtained ; 1. The shear bonding strength of single bonding agent was significantly higher than that of All-In-One system(P<0.05). 2. The shear bonding strength of All-In-One system applied twice or 3 times were higher than that of applied once (P<0.05). And thickness of the hybrid layer was increased when applied twice or 3 times compared to once. 3. The shear bonding strength of All-In-One system when applied for 15 second and 30 second were higher than that of 7 second (P<0.05). And the hybrid layer thickness of 15 second and 30 second's application time were higher than that of 7 second. 4. Thickness of hybrid layer applied with single bonding agent was $2-4{\mu}m$ and that of All-In-One system was $1-2{\mu}m$.

• Journal of Chest Surgery
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• v.26 no.8
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• pp.654-660
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• 1993

The incidence of pulmonary leiomyosarcoma is very rare as a primary lung tumor. Usually, pulmonary leiomyosarcoma arise from the smooth muscle present in the bronchi or blood vessles. We had experienced two cases of primary pulmonary leiomyosarcoma. The first case was 28-year old male patient who had been in good health until admission, when he experienced an episode of dyspnea and sudden hemoptysis. The chest X-ray film revealed a large round tumor mass in left lower lobe measuring 6.5x9.5x5.3cm in dimension. On physical examination,the patient was friction rub and rales on the left lower chest and postoperative course was smooth and non-eventful. Emergency left lower lobectomy was performed due to repeated hemoptysis. Chemotheraphy was done postoperatively as an adjuvant therapy.The second case was 52-year-old man who had been well prior to admission, when recently he noticed a abrupt growing tendency of old pulmonary coin lesion in right lower lobe on routine physical examination. Since 1968, small round mass was gradually enlarged very slowly, during recent one year interval, the tumor mass was enlarged abruptly as twice in size on chest X-ray. Bronchoscopic examination revealed no specipic findings. Right lower lobectomy was performed and pathologic examination was answered as primary leiomyosarcoma without lymph node metastasis. Postoperative course was smooth, except local wound infection.