• Restorative Dentistry and Endodontics
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• v.28 no.6
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• pp.485-490
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• 2003

Complete understanding of the exterior and interior structure of the tooth would be prerequisite to the successful clinical results, especially in the restorative and endodontic treatment. Although three-dimensional reconstruction method using x-ray microtomography could not be used in clinical cases, it may be the best way to reconstruct the morphologic characteristics of the tooth structure in detail without destructing the tooth itself. This study was done to three dimensionally reconstruct every teeth in the arch in order to increase the understanding about the endodontic treatment and to promote the effective restorative treatment by upgrading the knowledge of the tooth morphology. After placing tooth between the microfocus x-ray tube and the image intensifier to obtain two-dimensional images of each level. scanning was done under the condition of 80 keV, $100{\;}\mu\textrm{m}$, 16.8 magnification with the spot size of $8{\;}\mu\textrm{m}$. Cross-section pixel size of $16.28{\;}\mu\textrm{m}$ and 48.83 cross-section to cross-section distance were also used. From the results of this study, precise three dimensional reconstructed images of every teeth could be obtained. Furthermore, it was possible to see image that showed interested area only, for example. enamel portion only, pulp and dentin area without enamel structure, pulp only, combination image of enamel and pulp, etc. It was also possible to see transparent image without some part of tooth structure. This image might be used as a guide when restoring and preparing the full and partial crown by showing the positional and morphological relationship between the pulp and the outer tooth structure. Another profit may be related with the fact that it would promote the understanding of the interior structure by making observation of the auto-rotating image of AVI file from the various direction possible.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3133-3139
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• 2023

Neutron imaging technology as a means of non-destructive detection of materials is complementary to X-ray imaging. Silicon photomultiplier (SiPM), a new type of optical readout device, has overcome some shortcomings of traditional photomultiplier tube (PMT), such as high-power consumption, large volume, high price, uneven gain response, and inability to work in strong magnetic fields. Its application in the field of neutron detection will be an irresistible general trend. In this paper, a thermal neutron imaging detector based on ⁶LiF/ZnS scintillation screen and SiPM array readout was developed. The design of the detector geometry was optimized by geant4 Monte Carlo simulation software. The optimized detector was evaluated with a step wedge sample. The results show that the detector prototype with a 48 mm × 48 mm sensitive area can achieve about 38% detection efficiency and 0.26 mm position resolution when using a 300 ㎛ thick ⁶LiF/ZnS scintillation screen and a 2 mm thick Bk7 optical guide coupled with SiPM array, and has good neutron imaging capability. It provides effective data support for developing high-performance imaging detectors applied to the China Spallation Neutron Source (CSNS).

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.3
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• pp.227-233
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• 2023

In this paper, to substitute the existing TWTA(Travailing Wave Tube Amplifier) component in small radar system, we developed the Ku band SSPA(Solid-State Power Amplifier) based on the fabrication of power MMIC (Monolithic Microwave Integrated Circuit) chips. For the development of the 500 W SSPA, the 40 W-grade power MMIC was designed by ADS(Advanced Design System) at Keysight company with UMS GH015 library, and was processed by UMS foundry service. And 70 W main power modules were achieved the 2-way T-junction combiner method by using the 40 W-grade power MMICs. Finally, the 500 W SSPA was fabricated by the wave guide type power divider between the drive power amplifier and power modules, and power combiner with same type between power modules and output port. The electrical properties of this SSPA had 504 W output power, -58.11 dBc spurious, 1.74 °/us phase variation, and -143 dBm/Hz noise level.

• Steel and Composite Structures
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• v.49 no.6
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• pp.615-631
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• 2023

To investigate the seismic behavior of steel slag self-stressing concrete-filled circular steel tubular (SSSCFCST) columns, 14 specimens were designed, namely, 10 SSSCFCST columns and four ordinary steel slag (SS) concrete (SSC)-filled circular steel tubular (SSCFCST) columns. Comparative tests were conducted under low reversed cyclic loading considering various parameters, such as the axial compression ratio, diameter-thickness ratio, shear-span ratio, and expansion ratio of SSC. The failure process of the specimens was observed, and hysteretic and skeleton curves were obtained. Next, the influence of these parameters on the hysteretic behavior of the SSSCFCST columns was analyzed. The self stress of SS considerably increased the bearing capacity and ductility of the specimens. Results indicated that specimens with a shear-span ratio of 1.83 exhibited compression bending failure, whereas those with shear-span ratios of 0.91 or 1.37 exhibited drum-shaped cracking failure. However, shear-bond failure occurred in the nonloading direction. The stiffness of the falling section of the specimens decreased with increasing shear-span ratio. The hysteretic curves exhibited a weak pinch phenomenon, and their shapes evolved from a full shuttle shape to a bow shape during loading. The skeleton curves of the specimens were nearly complete, progressing through elastic, elastoplastic, and plastic stages. Based on the experimental study and considering the effects of the SSC expansion rate, shear-span ratio, diameter-thickness ratio, and axial compression ratio on the seismic behavior, a peak displacement coefficient of 0.91 was introduced through regression analysis. A simplified method for calculating load-displacement skeleton curves was proposed and loading and unloading rules for SSSCFCST columns were provided. The load-displacement restorative force model of the specimens was established. These findings can serve as a guide for further research and practical application of SSSCFCST columns.

• Journal of the Korean Society of Radiology
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• v.11 no.3
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• pp.171-175
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• 2017

In the non-destructive inspection field, we invest a lot of time and resources in developing the radiation source system to ensure the safety of the workers. However, the probability of accidents is still high. In order to prevent potential radiation accidents in advance, it is necessary to directly verify the position of the radiation source, but the research is still insufficient. In this study, we developed a monitoring system that can detect the position of the radiation source in the source guide tube in the gamma-ray irradiator. The characteristics of the radiation detector are estimated by monte carlo simulation. As a result, the radiation detector for Ir-192 gamma-ray energy was analyzed to have secondary electron equilibrium at $150{\mu}m$ regardless of the semiconductor material. Also, it is expected that the gamma ray response characteristic is the best in $HgI_2$. These results are expected to be used as a basis for determining the optimal thickness of the radiation detector located in the detection part of the future monitoring system. In addition, when developing a monitoring system based on this, radiation workers can easily recognize the danger and secure safety, as well as prevent and preemptively respond to potential radiation accidents.

• Journal of Radiation Protection and Research
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• v.30 no.2
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• pp.55-60
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• 2005

The evaluation of neutron flux distribution was performed for the ex-core detector design of SMART-P. DORT and MCNP code were used for the calculation of energy-dependent neutron flux distribution at 100% full power condition. Two code results show that maximum thermal flux appears at the $1^{st}$ water region in IST region and agree within 10% difference. In addition, another evaluation was performed code with assumptions that cote was composed of fission source and control rod without fuel assemblies. These assumptions make neutron count rate to be minimized. As a results, maximum thermal flux showed $6.99{\times}10^{-2}(n/cm^2-sec)$, when the strength of initial fission source was assumed as $1.0{\times}10^8(n/sec)$. The main reason of these results is due to the thermalization of fast neutrons in the water region and thermal flux is proportional to 80% of total neutron flux. Therefore, optimization of filler material of detector guide tube, position of installation and axial length of detector segments is necessary for the design of ex-core detector to enhance the neutron count rate and above results could be used in ex-core detector design as a fluence requirement.

• Journal of the Korean Institute of Oriental Medical Informatics
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• v.14 no.1
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• pp.55-61
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• 2008

The Taekwondo is the martial arts where possibility thousand Ul of history and the ancestor is put in with specific martial arts of our nation. Also it practiced with the self defense martial arts which rules over the body and a mind and it came, the country from crisis of imminent danger won a victory with the good state affair alcoholic beverage and it was come. The ancestors condition anger the Taekwondo where the soul is put in were born again with martial arts of the world and they became and the world-wide conference was adopted with the Olympic formal item which becomes the historian of of course sports and became the martial arts in the world-wide center. In like this features martial arts even from each country condition anger and the sports raises the phase of the country is racing with of course martial arts. Specially from China it makes the right shoe which is a Chinese martial arts with condition item and sports anger the features of the martial arts origination to do and there is a possibility of seeing the features which in the succession nose sleeping martial arts perforation defends it concentrates. The martial arts perforation character is letting in religion and philosophy thought of the Orient. Confucianism and Buddhism, it puts in the teaching of friendship thoughts and heaven and earth positive and negative principles, five lines and eight divination signs. Features of like this perforation our ancestors the positive and negative principles where the philosophy of the Orient is put in, there is a possibility of searching from life and the Taekwondo which it does with at five events together. With history of the ancestor it breathes together and all Taekwondo operation every one by one it puts in the thought of our ancestors as well. The some branch it tried to listen to the representative example which the feather holds hereupon in basic operation, the Taoist garment, the belt and width tax of Taekwondo. The flesh which is healthy in the spirit which is healthy holds the feather. Taekwondo Oh! as the true feelings one martial art which accomplishes the artificial flower of the dynamic thing and the static thing at end with the perforation essentially it is deep it will be able to confirm repeatedly fire tube characteristic.

• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.295-303
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• 2023

South Korea has recently witnessed an increasing number of seismic events, leading to a surge in studies focusing on seismic earth pressures, as well as the attributes of geological layers and ground where foundations are established. Consequently, earthquake-resistant design has become imperative to ensure the safety of subterranean structures. The slurry wall method, due to its superior wall rigidity, excellent water resistance, and minimal noise and vibration, is often employed in constructing high-rise buildings in urban areas. However, given the separation between panels that constitute the wall, slurry walls possess limited resistance to seismic loads in the longitudinal direction. As a solution, several studies have probed into the possibility of interconnecting slurry wall panels to augment their seismic performance. In this research, we developed and evaluated a method for linking slurry wall panels using mechanical joints, including concrete-confined steel pipes and headed bars, through mock-up tests. We also assessed the constructability of the suggested method and compared it with other analogous methods. Any challenges identified during the mock-up test were discussed to guide future research in resolving them. The results of this study aid in enhancing the seismic performance of slurry walls through the development of an interconnected panel method. Further research can build on these findings to address the identified issues and improve the efficacy and reliability of the proposed method.

• Therapeutic Science for Rehabilitation
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• v.11 no.1
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• pp.21-33
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• 2022

Purpose : The purpose of this study was to establish scientific evidence though a systematic review, of the existing interventional methods and their respective effects, for swallowing disorders among dementia patients. The interventional methods were based on patient characteristics. Methods : An electronic literature search was performed using five electronic databases from 2010 to 2020. The keywords were 'Dementia', 'Alzheimer disease', 'Deglutition disorder', 'Swallowing disorder', 'Dysphagia'. Five articles met the inclusion criteria. Results : One study with moderate-to-severe and four studies with severe dementia patients were included. The interventions consisted of one remedial intervention, three compensatory interventions, and one comprehensive intervention. Compensatory intervention, including behavioral and psychological management, were used in moderate-to-severe patients. For the severe patients, remedial, compensatory, and comprehensive intervention were used to address the feeding tube problem. The interventions used in each study had a positive effect on the outcome variables associated with swallowing ability. Conclusion : The purpose of the intervention and the intervention factors changed depending on the patient's dementia stage. The intervention was effective when considering the progressive stage of the patient. These results may serve as a guide in designing effective interventions for swallowing disorders in dementia patients.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.357-364
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• 2000

Background : Complicated exudative pleural fluid collections have traditionally been treated by either closed tube thoracostomy drainage or by open surgical drainage. Complete drainage is important in order to control pleural sepsis, restore pulmonary function, and entrapment. Recently intracavitary fibrinolytic therapy has been advocated as a method to facillitate drainage of complicated exudative pleural effusion and to allow enzymatic debridemant of the restrictive fibrinous sheets covering the pleural surface. The purpose of this study is to prospectively evaluate the effects of image-guided catheter drainage with high dose urokinase(UK) instillation in the treatment of complicated pleural effusions. Patients : Twenty complicated pleural effusion patients that poorly respond to image-guided drainage were allocated to receive UK. There were 8 pneumonia and 12 tuberculosis. Methods : Drugs were diluted in 250 mL normal saline and were infused intrapleurally through the chest tube or pig-tail catheter in a daily dose of 250,000 IU of UK. Response was assessed by clinical outcome, fluid drainage, chest radiography, pleural ultrasound and/or computed tomography. Results : The mean UK instillation time was $1.63{\pm}0.10$. The mean volume drained UK instillation was $381.3{\pm}314.4\;mL$, and post-UK was $321.6{\pm}489.5\;mL$. The follow up duration after UK therapy was mean $212.9{\pm}194.5$ days. We had successful results in 19 cases (95.0%). There were 12 pleural thickenings (60.0%), 2 markedly decreased effusions (10.0%) and 5 cases of no thickening or effusion. There was recurrence after treatment in only one patient(5%) with complicated pleural effusiondue to tuberculosis. Conclusions : Image-guided drainage with high dose UK instillation (250,000 U/day) in complicated pleural effusion is a safe and more effective method than closed thoracostomy drainage. And this management, in turn, can obviate surgery in most cases.