• Nuclear Engineering and Technology
• /
• 제49권4호
• /
• pp.781-786
• /
• 2017

The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.

• 한국주조공학회지
• /
• 제30권3호
• /
• pp.100-110
• /
• 2010

The solidification sequence and formation of intermetallic phase of Fe-rich Al-Si-Cu alloy were investigated by using real-time imaging of synchrotron X-ray radiation. Effects of cooling rate during uni-directional solidification on the resultant solidification behavior was also studied in a specially constructed vacuum chamber in the SPring-8 facility. The series of radiographic images were complementarily analyzed with conventional analysis of OM and SEM/EDX for phase identification. Detailed solidification sequence and formation mechanisms of various phases were discussed based on real-time image analysis. The growth rates of $\alpha$-AlFeMnSi and ${\beta}-Al_5FeSi$ were measured in order to understand the growth behavior of each phase. It is suggested that real-time imaging technique can be a powerful tool for the precise understanding of solidification behavior of various industrial materials.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
• /
• pp.817-820
• /
• 2002

Amorphous selenium based flat panel detectors convert incident x-ray to electric signal directly. Flat panel detectors gain more interest real time medical x-ray imaging. TFT array and electric readout circuits are used in this paper offered by LG.Philips.LCD. Detector is based on a $1536{\times}1280$ array of a-Si TFT pixels. X-ray conversion layer(a-Se) is deposited upper TFT array with a $400{\mu}m$ by thermal deposition technology. Thickness uniformity of this layer is made of thickness control system technology$({\leq}5%)$. Each $139{\mu}m{\times}139{\mu}m$ pixel is made of thin film transistor technology, a storage capacitor and collecting electrode having geometrical fill factor of 86%. This system show dynamic performance. Imaging performance is suited for digital radiography imaging substitute by conventional radiography film system.

• 한국주조공학회지
• /
• 제30권1호
• /
• pp.5-13
• /
• 2010

This article aims to introduce the synchrotron radiation for its utilization in the casting and solidification fields as an unique tool for observation of real time phenomena of molten metal during solidification. General features of the synchrotron radiation were briefly introduced for readers in the casting and solidification fields, with no background regarding to synchrotron radiation. And basic principles of imaging technologies using synchrotron light for in-situ observation of molten metal were explained together with exemplary research works, which were reported on the casting and solidification fields in recent years. As a practical guide, real time observation of Al-Si casting alloy was introduced with experimental facilities, image acquisition, and processing together with representative results.

• Journal of Gastric Cancer
• /
• 제21권1호
• /
• pp.4-15
• /
• 2021

Recently, endoscopic screening systems have enabled the diagnosis of gastric cancer in the early stages. Early gastric cancer (EGC) is typically characterized by a shallow invasion depth and small size, which can hinder localization of EGC tumors during laparoscopic surgery. Here, we review nine recently reported tumor localization methods for the laparoscopic resection of EGCs. Preoperative dye or blood tattooing has the disadvantage of spreading. Preoperative 3-dimensional computed tomography reconstruction is not performed in real time during laparoscopic gastrectomy. Thus, they are considered to have a low accuracy. Intraoperative portable abdominal radiography and intraoperative laparoscopic ultrasonography methods can provide real-time feedback, but these methods require expertise, and it can be difficult to define the clips in some gastric regions. Despite a few limitations, intraoperative gastrofibroscopy provides real-time feedback with high accuracy. The detection system using an endoscopic magnetic marking clip, fluorescent clip, and radio-frequency identification detection system clip is considered highly accurate and provides real-time feedback; we expect a commercial version of this setup to be available in the near future. However, there is not yet an easy method for accurate real-time detection. We hope that improved devices will soon be developed and used in clinical settings.

• 대한방사선기술학회지:방사선기술과학
• /
• 제44권6호
• /
• pp.599-605
• /
• 2021

The International Electrotechnical Commission (IEC) 62494-1 has defined the exposure index (EI) that have a proportional relationship with the dose incident on the image receptor, and target exposure index (EI_T), deviation index (DI). In this study, an appropriate EI_T for skull radiography was established through the diagnostic reference level (DRL) and changes in DI were confirmed. Entrance surface dose (ESD) and EI were obtained using the computed radiography system displayed the EI as per IEC on console and skull phantom by experiment based on the national average exposure conditions announced in 2012 and 2019. And appropriate EI_T was established by applying the DRL in 2012 and 2019. As a results, the EI_T is changed according to the change in the DRL, and the exposure condition that becomes the ideal DI according to the change in the EI_T also has a difference of about 1.41 times. DRL is recommended to optimize the patient dose, however it is difficult to measure in real time at medical institutions whereas EI and DI are displayed on the console at the same time as exposure. When the EI_T is set based on the DRL and the DI is closed to an ideal value, it is useful as a patient dose management tool. Therefore, when the EI_T is periodically managed along with the revision of the DRLs, the patient dose can be optimized through the EI, EI_T and DI.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 D
• /
• pp.3230-3232
• /
• 2000

DR (Digital Radiography) system will be the best candidate for next generation x-ray diagnosis system. DR system will replace x-ray film by computer monitor and provide various merits like reduced processing time, easy recording, remote diagnosis and etc. In this paper, we propose the pre-processing algorithm which is designed to compensate dead and defected pixel for x-ray detector panel. We also designed DSP(Digital Signal Processor) based DR image processing board for real-time processing of suggested algorithm.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
• /
• pp.388-391
• /
• 2003

The properties of these detectors can be controlled by electronics and exposure conditions. Flat-panel detectors for digital diagnostic imaging convert incident x-ray images to charge images. Flat panel detectors gain more interest real time medical x-ray imaging. Active area of flat panel detector is $14{\times}17$ inch. Detector is based on a $2560{\times}3072$ away of photoconductor and TFT pixels. X-ray conversion layer is deposited upper TFT array flat panel with a 500m by thermal deposition technology. Thickness uniformity of this layer is made of thickness control technology(5%) of thermal deposition system. Each $139m{\times}139m$ pixel is made of thin film transistor technology, a storage capacitor and charge collection electrode having geometrical fill factor of 86%. Using the separate driving system of two dimensional mosaic modules for large area, that is able to 4.2 second per frame. Imaging performance is suited for digital radiography imaging substitute by conventional radiography film system..

• 한국임상수의학회지
• /
• 제16권2호
• /
• pp.523-528
• /
• 1999

Subaortic stenosis in a 2.9kg, 3-month-old pug dog and a 11 kg, 4-month-old Rott -weiler dog showing signs of dyspnea, tachypnea, anorexia, exercise intolerance and depression was diagnosed with electrocardiography, thoracic radiography and ultrasonographic evaluation. In electrocardiography, PR interval widening, R wave amplitude increase in lead II in case 2, ST segment depression and left axis deviation in case 1 and 2 were identified. In thoracic radiographs, enlarged left ventricle and atrium, caudal displacement of left crus of diaphragm and caudal part of cranial mediastinum widening were identified in ventrodorsal view. In lateral view, left ventricular enlargement, secondary dorsal deviation of trachea and post-stenotic dilation of aorta were seen. Also, edematous pulmonary changes were shown in peri-hilar area. In ultrasonographic examination, left ventricular dilatation, pericardial effusion and subaortic valvular ridge were seen with real time B-mode in right parasternal long axis view. Aortic valve regurgitation was identified in color-Doppler mode.

• Journal of Welding and Joining
• /
• 제35권2호
• /
• pp.63-70
• /
• 2017

As the Non Destructive Test (NDT) for the welded structure, PT(Penetration Test). MT(Magnetic Test), RT (Radioisotope Test) and UT(Ultrasonic Test) methods are widely used in practice. These NDT methods have been developed toward high efficiency, low cost, real time, and high precise new NDT. For example, RT methods are developed to CT(Computed Tomography)and DR(Digital Radiography), and UT metheds are developed into Phased array, Guide wave, TOFD method. Moreover, the Infrared thermography and Laser ultrasonic technique are newly developed for applying in high temperature objects as the non-contact NDT methods. In this review paper the new high efficiency NDT methods for the welded structure are introduced and the trend of NDT rules applying in welded structure are described.