• Clean Technology
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• v.23 no.1
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• pp.90-94
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• 2017

These days much efforts are being dedicated to wind power as a potential source of renewable energy. To maintain effective and uniform generation of energy, defect preservation of turbine blade is essential because it directly takes effects on the efficiency of power generation. For the effective maintenance, early measurements of blade defects are very important. However, current technologies such as ultrasonic waves and thermal imaging inspection methods are not suitable because of long inspection time and non-real time inspection. To supplement the problems, the study introduced a method for real time defect monitoring of a blade surface based on surface wave technology. We examined the effect of various parameters such as micro-cracks and peelings on the propagation of surface wave.

• Journal of Periodontal and Implant Science
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• v.48 no.2
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• pp.84-91
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• 2018

Purpose: The purpose of this study was to visualize and identify peri-implant bone defects in optical coherence tomography (OCT) images and to obtain quantitative measurements of the defect depth. Methods: Dehiscence defects were intentionally formed in porcine mandibles and implants were simultaneously placed without flap elevation. Only the threads of the fixture could be seen at the bone defect site in the OCT images, so the depth of the peri-implant bone defect could be measured through the length of the visible threads. To analyze the reliability of the OCT measurements, the flaps were elevated and the depth of the dehiscence defects was measured with a digital caliper. Results: The average defect depth measured by a digital caliper was $4.88{\pm}1.28mm$, and the corresponding OCT measurement was $5.11{\pm}1.33mm$. Very thin bone areas that were sufficiently transparent in the coronal portion were penetrated by the optical beam in OCT imaging and regarded as bone loss. The intraclass correlation coefficient between the 2 methods was high, with a 95% confidence interval (CI) close to 1. In the Bland-Altman analysis, most measured values were within the threshold of the 95% CI, suggesting close agreement of the OCT measurements with the caliper measurements. Conclusions: OCT images can be used to visualize the peri-implant bone level and to identify bone defects. The potential of quantitative non-invasive measurements of the amount of bone loss was also confirmed.

• Journal of Cardiovascular Imaging
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• v.31 no.4
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• pp.180-187
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• 2023

BACKGROUND: Two-dimensional (2D) transesophageal echocardiography (TEE) is commonly used for assessing patients undergoing transcatheter atrial septal defect (ASD) device closure. 3D TEE, albeit providing high resolution en-face images of ASD, is used in only a fraction of cases. We aimed to perform a comparative analysis between 3D and 2D TEE assessment for ASD device planning. METHODS: This was a prospective, observational study conducted over a period of one year. Patients deemed suitable for device closure underwent 2D and 3D TEE at baseline. Defect characteristics, assessed separately in both modalities, were compared. Using regression analysis, we aimed to derive an equation for predicting device size using 3D TEE parameters. RESULTS: Thirty patients were included in the study, majority being females (83%). The mean age of the study population was 40.5 ± 12.05 years. Chest pain, dyspnea and palpitations were the common presenting complaints. All patients had suitable rims on 2D TEE. A good agreement was noted between 2D and 3D TEE for measured ASD diameters. 3D TEE showed that majority of defects were circular in shape (60%). The final device size used had high degree of correlation with 3D defect area and circumference. An equation was devised to predict device size using 3D defect area and circumference. The mean device size obtained from the equation was similar to the actual device size used in the study population (p = 0.31). CONCLUSIONS: Device sizing based on 3D TEE parameters alone is equally effective for transcatheter ASD closure as compared to 2D TEE.

• Journal of the Korean Arthroscopy Society
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• v.17 no.1
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• pp.6-10
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• 2013

Purpose: This study intends to verify the usefulness of magnetic resonance imaging (MRI) for estimate recovery after arthroscopic pull-out repair at root tears of medial meniscus. Materials and Methods: We performed 17 patients who examined MRI and arthroscopy among patients who had received repair of medial meniscus from November, 2007 to June, 2011. To determine restoration meniscus, we performed arthroscopy and MRI. Results: Lysholm knee scores before and after operation were average 56.4 and 79.0 and visual analogue scale (VAS) score was improved from 8 points to 3 points. From secondary look arthroscopy performed after operation, 17 cases showed stabilization after regeneration. However, In MRI, cleft sign implying root tears of medial meniscus was observed in all cases before and after operation, ghost sign was observed in 10 cases and 9 cases respectively, radial linear defect was showed 17 cases and 15 cases respectively. Conclusion: It was not useful that MRI after medial meniscus repair in non-anatomical site, to consider restoration of medial meniscus. To evaluate for recovery medial meniscus after repair more exactly, secondary arthroscopy would be required.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.77-78
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• 2008

A 71-year-old woman was assigned to our department for Tc-99m myocardial perfusion SPECT(MPS) and coronary CT angiography. She admitted for substernal pain, via the ER, 2 days ago. The heart was scanned after intravenous injection of 925 MBq of $^{99m}Tc$-sestamibi adenosine-induced stress SPECT using dual head gamma camera (Hawkeye, GE healthcare. USA). The MPS shows decreased tracer uptake in the apical & mid area of anterior & lateral wall and mid & basal inferior wall. Coronary CT angiograph was obtained using Discovery VCT (GE healthcare). 3D angiography portrayed significant stenosis of ramus intermedius(RI) and posterolateral branch of right coronary artery(PLB) with fibrocalcified plaque. Two images were fused using Cardiac IQ fusion softwear package (Advantage workstation 4.4, GE healthcare) The fusion images explain the perfusion defect of anterior, lateral and inferior wall is due to stenosis of the RI and PLB. And 3 days later, coronary angiography was done and revealed the marked stenosis of RI and PLB. Then balloon angioplasty and stent was instituted in RI. Cardiac SPECT/CT fusion imaging provides additional information about hemodynamic relevance and facilitates lesion interpretation by allowing exact allocation of perfusion defects to its subtending coronary artery.

• Imaging Science in Dentistry
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• v.49 no.4
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• pp.265-272
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• 2019

Purpose: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel(PPA) and oblique projected periapical(OPA) radiography for the detection of different types of peri-implant bone defects. Materials and Methods: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects(10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. Results: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects(P<0.05). Conclusion: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2085-2092
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• 2016

One of the most important properties of the IC substrate is that it should be uniform over large areas. Among the various physical approaches of wafer defect characterization, special attention is to be payed to the infrared techniques of inspection. In particular, a high spatial resolution, near infrared absorption method has been adopted to directly observe defects in semi-insulating GaAs. This technique, which relies on the mapping of infrared transmission, is both rapid and non-destructive. This method demonstrates in a direct way that the infrared images of GaAs crystals arise from defect absorption process. A new interpretation is presented for the observed reversal of contrast in the infrared absorption of nonuniformly distributed deep centers, related to EL2, in semi-insulating GaAs. The low temperature photoquenching experiment has demonstrated in a direct way that the contrast inverse images of GaAs wafers arise from both absorption and scattering mechanisms rather than charge re-distribution or local variation of bandgap.

• Journal of Chest Surgery
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• v.54 no.1
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• pp.45-52
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• 2021

Background: Atrial septal defect (ASD) is the most common congenital heart disease. However, the details of cardiac chamber remodeling after surgery are not well known, although this is an important issue that should be analyzed to understand long-term outcomes. Methods: Between November 2017 and January 2019, cardiac magnetic resonance imaging was performed preoperatively, at a 1-month postoperative follow-up, and at a 1-year postoperative follow-up. Cardiac chamber volume, valve regurgitation volume, and ejection fraction were measured as functions of time. Results: Thirteen patients (10 men and 3 women) were included. The median age at surgery was 51.4 years. The preoperative median ratio of flow in the pulmonary and systemic circulation was 2.3. The preoperative mean right ventricular (RV) end-diastolic volume index (EDVi) and RV end-systolic volume index (ESVi) had significantly decreased at the 1-month postoperative follow-up (p<0.001, p=0.001, respectively). The decrease in the RVEDVi (p=0.085) and RVESVi (p=0.023) continued until the postoperative 1-year follow-up, although the rate of decrease was slower. Tricuspid valve regurgitation had also decreased at the 1-month postoperative follow-up (p=0.022), and continued to decrease at a reduced rate (p=0.129). Although the RVEDVi and RVESVi improved after ASD closure, the RV volume parameters were still larger than the left ventricular (LV) volume parameters at the 1-year follow-up (RVEDVi vs. LVEDVi: p=0.016; RVESVi vs. LVESVi: p=0.001). Conclusion: Cardiac remodeling after ASD closure is common and mainly occurs in the early postoperative period. However, complete normalization does not occur.

• Imaging Science in Dentistry
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• v.52 no.3
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• pp.303-308
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• 2022

Purpose: This technical report aims to describe and detail the use of micro-computed tomography for a reliable evaluation of the bulk-fill composite/tooth interface. Materials and Methods: Bulk-fill composite restorations in tooth cavities were scanned using micro-computed tomography to obtain qualitatively and quantitatively valuable information. Two-dimensional information was processed using specific algorithms, and ultimately a 3-dimensional (3D) specimen reconstruction was generated. The 3D rendering allowed the visualization of voids inside bulk-fill composite materials and provided quantitative measurements. The 3D analysis software VG Studio MAX was used to perform image analysis and assess gap formation within the tooth-restoration interface. In particular, to evaluate internal adaptation, the Defect Analysis addon module of VG Studio Max was used. Results: The data, obtained with the processing software, highlighted the presence and the shape of gaps in different colours, representing the volume of porosity within a chromatic scale in which each colour quantitatively represents a well-defined volume. Conclusion: Micro-computed tomography makes it possible to obtain several quantitative parameters, providing fundamental information on defect shape and complexity. However, this technique has the limit of not discriminating materials without radiopacity and with low or no filler content, such as dental adhesives, and hence, they are difficult to visualise through software reconstruction.

• 한국환경농학회:학술대회논문집
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• 2009.07a
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• pp.119-126
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• 2009

In recent years, research at the Environmental Microbial and Food Safety Laboratory (EMFSL), Agricultural Research Service (ARS) has focused on the development of novel image-based sensing technologies to address agro-food safety concerns, and transformation of these novel technologies into practical instrumentation for industrial implementations. The line-scan-based hyperspectral imaging techniques have often served as a research tool to develop rapid multispectral methods based on only a few spectral bands for rapid online applications. We developed a newer line-scan hyperspectral imaging platform for high-speed inspection on high-throughput processing lines, capable of simultaneous multiple inspection algorithms for different agro-food safety problems such as poultry carcass inspection for wholesomeness and apple inspection for fecal contamination and defect detection. In addition, portable imaging devices were developed for in situ identification of contamination sites and for use by agrofood producer and processor operations for cleaning and sanitation inspection of food processing surfaces. The aim of this presentation is to illustrate recent advances in the above agro.food safety sensing technologies.