• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.57.1-57.9
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• 2021

Objectives: This study aimed to compare and evaluate the porosity and pore size distribution of high-viscosity glass ionomer cements (HVGICs) and conventional glass ionomer cements (GICs) using micro-computed tomography (micro-CT). Materials and Methods: Forty cylindrical specimens (n = 10) were produced in standardized molds using HVGICs and conventional GICs (Ketac Molar Easymix, Vitro Molar, MaxxionR, and Riva Self-Cure). The specimens were prepared according to ISO 9917-1 standards, scanned in a high-energy micro-CT device, and reconstructed using specific parameters. After reconstruction, segmentation procedures, and image analysis, total porosity and pore size distribution were obtained for specimens in each group. After checking the normality of the data distribution, the Kruskal-Wallis test followed by the Student-Newman-Keuls test was used to detect differences in porosity among the experimental groups with a 5% significance level. Results: Ketac Molar Easymix showed statistically significantly lower total porosity (0.15%) than MaxxionR (0.62%), Riva (0.42%), and Vitro Molar (0.57%). The pore size in all experimental cements was within the small-size range (< 0.01 mm³), but Vitro Molar showed statistically significantly more pores/defects with a larger size (> 0.01 mm³). Conclusions: Major differences in porosity and pore size were identified among the evaluated GICs. Among these, the Ketac Molar Easymix HVGIC showed the lowest porosity and void size.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.568-571
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• 1997

Recently, the number of techniques for analyzing medical images has been increasing in computer vision, employing X-ray CT images, ultrasound images, MR images, moire topographic images, etc. Spinal deformity is a serious problem especially for teenagers and medical doctors inspect moire topographic images of their backs visually for the primary screening. If a subject is normal, the moire image is almost symmetric with respect to the middle line of the subject's back, otherwise it shows asymmetric shape. In this paper, an image analysis technique is described for discriminating suspicious cases from normal in human spinal deformity by recognizing asymmetric moire images of human backs. The principal axes which are sensitive to asymmetry of the moire image are extracted at two parts on a subject's back and their angles are evaluated with respect to the detected middle line of the back. The two angles compose a 2-D feature space and inspected cases are divided into two clusters in the space by a linear discriminant function based on the Mahalanobis distance. Given 120 cases, 60 normal and 60 abnormal, the leave-out method was applied for the recognition and 75% recognition rate was achieved.

• 한국정밀공학회지
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• 제28권1호
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• pp.80-88
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• 2011

The dental high-speed air turbine handpiece is one of the most popular devices that have been widely used as the main means of cutting tooth structure and restorative material in dentistry. In consideration of usage and marketability of the dental handpiece, it is obviously worthy of investigating it. The goal of this paper is to establish the relationship between the air turbine speed and the supply route inside the handpiece. To do this, the Computational Fluid Dynamics(CFD) tool, Fine$^{TM}$/Turbo is used and the optimal supply route position is suggested from the simulation results. In addition, as an attempt for domestic product, the reverse engineering process of a high speed dental handpiece by 3D X-Ray CT equipment and wire cutting is presented for the Mark II model in NSK. In doing so, the 3D modeling of the handpiece parts is carried out with CATIA V5, and the interference between parts is examined. Finally, the result of performance test for the prototype produced in this research is presented.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.51.1-51.1
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• 2011

An electrospun Poly (lactice-co-glycolide acid) (PLGA) and Gelatin nanofiber tube was fabricated for potential intestinal stent application. Mechanical properties of tube were evaluated by tensile strength and burst strength tests. Physical and chemical properties were evaluated by contact angle measurement, swelling rates and porosity measurements. Biodegradability was investigated by immersion in simulated body fluid (SBF). Biocompatibility was investigated in vitro by cytotoxicity and proliferation studies by MTT assay, confocal microscopy and western blot using IEC-18 (Rat intestinal epithelial cell). After intestinal stent was implanted into rat bowel for periods from 7 to 10days, it was then analyzed using micro-computed tomography (Micro CT) and X-ray techniques. Futhermore, histological analysis was performed by hematoxylin-eosin (H&E) stain.

• Journal of Yeungnam Medical Science
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• 제30권1호
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• pp.51-54
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• 2013

Synovial sarcoma is a rare malignancy in the thoracic cavity, especially in the mediastinum. In this paper, a case of primary mediastinal synovial sarcoma is reported. A 34-year-old woman was hospitalized with dyspnea. Her chest X-ray and computed tomography (CT) showed a $16{\times}13{\times}11$ cm mass in her anterior mediastinal space. Surgical resection was performed but was incomplete. The pathological and immunohistochemical analysis confirmed the diagnosis of monophasic spindle cell synovial sarcoma. The patient underwent adjuvant radiotherapy for two months, but local recurrence and metastasis occurred in her pleural cavity. She eventually underwent chemotherapy for one year and died 18 months after her operation.

• Journal of Chest Surgery
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• 제26권1호
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• pp.54-58
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• 1993

Simultaneous bilateral bleb resection was done through bilateral transaxillary thoracotomy in 10 patients with spontaneous pneumothorax during the period from May 1991 to Novemver 1992 in whom bilateral bulla or bleb was detected with using simple chest X-ray and chest CT scanning. To compare the effectiveness of bilateral transaxillary thoracotomy, we investigated 10 unilateral transaxillary thoracotomy patients with spontaneous pneumothorax and two clinical reports from other institutes which dealt the results of bilateral bleb or bulla resection through median sternotomy also. In bilateral transaxillary thoracotomy group,mean operation time was 115 minute,mean intraoperative bleeding was 329 cc, mean postoperative hospital stay was 7.5 days. Postoperative ABGA[Arterial Blood Gas Analysis] was in normal range and postoperative recovery rates of FVC[Forced Vital Capacity], FEV1[Forced Expiratory Volume at 1 second], TV[Tidal Volume] were 84.3%, 93.4%, 88.7%,respectively. In median sternotomy group,mean operation time was 129 minute,mean intraoperative bleeding was 490 cc, mean postoperative hospital stay was 12.4 days. Postoperative ABGA was in normal range and postoperative recovery rates of FVC, FEV1 were 97.3%, 97.4%, respectively. In unilateral transaxillary thoracotomy group, postoperative ABGA was in normal range also and postoperative recovery rates of FVC, FEV1, TV were 91.6%, 99.0%, 96.0%,respectively. In conclusion, simultaneous bilateral bleb resection through bilateral transaxillary thoracotomy should be considered in pneumothorax patients with bilateral bleb or bulla because of cost-effectiveness[reducing hospital days] and better cosmetic result without any impairment in recovery of respiratory function.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.249-257
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• 1999

A three dimensional finite model of a human neck has been developed in an effort to study the mechanics of cervical spin while subjected to vertical impact. This model consisting of the vertebrae from C1 through C7 including posterior element and ligaments was constructed by 2mm thick transverse CT cross-sections and X-ray film taken at lateral side. Geometrical nonlinearity was also considered for the large deformation on the disc. ABAQUS package was used for calculation and its results were verified comparing with responses of a model under static loading condition with published in-vitro experimental data. There were more cervical fracture in the restrained (compression) mode than in the nonrestrained (flexion-compression and extension-compression) mode. Upper cervical(C1-C2) injuries were observed under compression-extension modes, while lower cervical injuries occurred undjer compression-flexion modes. Posterior ligament distraction without bony damage at the upper cervical spin(C1-C2) were observed secondary to C5-C7 trauma in compression-flexion modes.

• 한국세라믹학회지
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• 제55권4호
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• pp.400-405
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• 2018

FCM nuclear fuel, a concept proposed as an accident tolerant fuel in light water reactors, consists of TRISO fuel particles embedded in a SiC matrix. The uniform dispersion of internal TRISO fuel particles in the FCM fuel is very important for improving the fuel efficiency. In this study, FCM sintered pellets with various volume ratios of TRISO-coated particles were prepared by hot press sintering. The distribution of TRISO-coated particles was quantitatively analyzed using X-ray ${\mu}CT$ and expressed as a dispersion uniformity index. TRISO-coated particles were most uniformly dispersed in the FCM pellets prepared using only overcoated TRISO particles without mixing of additional SiC matrix powder. FCM pellets with uniformly dispersed TRISO particle volume fraction of up to 50% were prepared using overcoated TRISO particles with varying thickness.

• Tuberculosis and Respiratory Diseases
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• 제67권3호
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• pp.239-243
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• 2009

Delftia acidovorans is a gram-negative motile rod found ubiquitously in soil and in water. Confirmed isolation from clinical infections is rare, and has been documented mostly in immunocompromised patients or those with indwelling catheters. A 53-year-old man was referred for the evaluation of a huge mass-like lesion found incidentally by chest X-ray. The lesion occupied more than half of the right lung and was diagnosed as a large loculated pleural effusion by CT scan. Bloody pus was drained through a percutaneous catheter, and D. acidovorans, identified by the Vitek GN card and confirmed by amplification of 16S ribosomal RNA and sequencing analysis, was isolated repeatedly from the drained pus. The patient was treated with imipenem/cilastatin to which the organism was sensitive. This is a rare report of chronic empyema associated with D. acidovorans in the respiratory system of an immunocompetent patient.

• 박물관보존과학
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• 제26권
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• pp.143-160
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• 2021

한성백제박물관에서는 백제 한성기 대표적인 왕실과 중앙세력의 분묘군으로 알려진 사적 제243호 석촌동 고분군의 학술 발굴조사를 실시하고 있으며, 그 과정에서 출토된 금제이식의 과학적 분석 및 보존처리를 실시하였다. 분석은 실체현미경 관찰, SEM, X-선 촬영, CT, XRF 분석을 실시하였고, 이를 통해 유물 특성, 내부 구조와 성분 등을 확인하고 제작 기법을 알아보고자 하였다. 연구결과, 금동이식의 주환은 동심재에 수은 아말감 금도금하였고, 중간식의 육면체는 금 분말을 용융시켜 소환을 이어 붙였으며 수하식 구체는 반구체 두 개를 땜하여 붙인 것을 확인하였다. 세환이식 2건은 표면 성분이 서로 유사하지만 동심재에 금판을 감싸 제작한 것과 금봉을 구부려 제작한 것으로 제작기법에 차이가 있음을 밝혔다. 금 함량은 유물에 따라, 측정 위치에 따라 다르지만 약 19~21K로 비교적 높은 금 함량을 보이며 정교한 공예기술로 만들어진 이식이라는 점에서 피장자의 우월적 지위와 석촌동 고분군의 위상을 판단할 수 있는 자료가 될 것으로 보인다.