• Imaging Science in Dentistry
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• 제51권1호
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• pp.1-7
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• 2021

Purpose: The aim of this study was to assess artifacts generated in cone-beam computed tomography (CBCT) of 3 types of dental implants using 3 metal artifact reduction (MAR) algorithm conditions (pre-acquisition MAR, post-acquisition MAR, and no MAR), and 2 peak kilovoltage (kVp) settings. Materials and Methods: Titanium-zirconium, titanium, and zirconium alloy implants were placed in a dry mandible. CBCT images were acquired using 84 and 90 kVp and at normal resolution for all 3 MAR conditions. The images were analyzed using ImageJ software (National Institutes of Health, Bethesda, MD) to calculate the intensity of artifacts for each combination of material and settings. A 3-factor analysis of variance model with up to 3-way interactions was used to determine whether there was a statistically significant difference in the mean intensity of artifacts associated with each factor. Results: The analysis of all 3 MAR conditions showed that using no MAR resulted in substantially more severe artifacts than either of the 2 MAR algorithms for the 3 implant materials; however, there were no significant differences between pre- and post-acquisition MAR. The 90 kVp setting generated less intense artifacts on average than the 84 kVp setting. The titanium-zirconium alloy generated significantly less intense artifacts than zirconium. Titanium generated artifacts at an intermediate level relative to the other 2 implant materials, but was not statistically significantly different from either. Conclusion: This in vitro study suggests that artifacts can be minimized by using a titanium-zirconium alloy at the 90 kVp setting, with either MAR setting.

• Ocean and Polar Research
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• 제44권1호
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• pp.39-59
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• 2022

How in the Antarctic icefish, generally, and Pseudochaenichthys georgianus, in particular, otoliths increase in size and build new material as the fish ages and passes through different life phases is largely unexplored. Morphometric details of 3418 otoliths of Ps. georgianus from S. Georgia and 318 from S. Shetland, were processed and proportions of the amounts of collagen and aragonite removed by EDTA were determined for different age groups. Microstructural investigations showed that characteristics of the 3-dimensinal collagen net are the reason for the radial direction and orientation of the aragonite needles of approximately 1.0 ㎛ in length in larval and 2.3 ㎛ in length in adult specimens. Earlier generated increment layers from the primordial centre (PC) in the dorsal direction restrict those of the secondary centre (SC), causing new growth layer accretion in different directions. In the otoliths of larval Ps. georgianus, aragonite layers are 0.89 ㎛ wide while in juveniles and adults they measure 1.45-2.86 ㎛. Otoliths change from a sphere shape in the larvae to a longish object of irregular outline in the older stages. It is tentaively suggested that the observed otolith shape differences at distinct growth stages are due to physical effects related to swimming speeds at particular water depths and locations. To confirm that otoliths, apart from being useful for age analyses, could also serve to establish correlations between developmental stage and the oceanic environment the fish spend time in, further analyses using additional species and state-of-the-art methods like µCT imaging to evaluate otolith volumes and shapes are required.

• 한국기계가공학회지
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• 제21권4호
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• pp.60-69
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• 2022

To keep pace with Industry 4.0, it is imperative for companies to redesign their working environments by adopting robotic automation systems. Automation lines are facilitating the latest cutting-edge technologies, such as 3D vision and industrial robots, to outdo competitors by reducing costs. Considering the nature of the manufacturing industry, a time-saving workflow and smooth linkwork between processes is vital. At Dellics, without any additional new installation in the automation lines, only a few improvements to the working process could raise productivity. Three requirements are the development of gripping technology by utilizing a 3D vision system for the recognition of the material shape and location, research on lighting projectors to target long distances and high illumination, and testing of algorithms/software to improve measurement accuracy and identify products. With some of the functional requisites mentioned above, improved robotic automation systems should provide an improved working environment to maximize overall production efficiency. In this article, the ways in which such a system can become the groundwork for establishing an unmanned working infrastructure are discussed.

• 대한본초학회지
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• 제32권6호
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• pp.63-69
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• 2017

Objectives : The purpose of this study is to investigate the preventive and therapeutic efficacy of osteoarthritis using a Yeonsan-Ogye egg. so, we researched at effects of Yeonsan-Ogye egg extract on MIA-induced Osteoarthritis animal models. Methods : Yeonsan-Ogye egg extract was administered 500 mg/kg/day, 1000 mg/kg/day and 2000 mg/kg/day to SD-Rat for 2 weeks. After that, osteoarthritis was induced with $60mg/m{\ell}$ of monosodium iodoacetate (MIA) and futher administration was continued for 4 weeks. 3D imaging of cartilage patella were obtained using a Micro-CT system and the pathology change of knee was observed by H&E and safranin-O staining. The weight bearing ratio was measured by incapacitance test meter. MMP-2, MMP-9, COMP, CTX II, calcitonin and glycosaminoglycan level in serum were measured using a ELISA. Results : Micro-CT and Histopathological analysis showed the volume of the patella cartilage and the proteoglycan contents were increased in all groups. also weight bearing ratio was decreased in all groups compared with control group. Calcitonin production was increased in and 2000 mg/kg/day group and glycosaminoglycan production was increased in all groups. In addition, MMP-2, MMP-9, COMP and CTX II production were decreased in 1000 and 2000 mg/kg/day groups respectively in comparison with control. Conclusions : The results for Yeonsan-Ogye egg showed prevention and treatment efficacy against arthritis at serum and the cartilage. These results may be used a remedy for new korea medicine to ease the symptoms mentioned above. also, suggest that Yeonsan-Ogye egg can be used preventive and therapeutic material for osteoarthritis.

• Smart Structures and Systems
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• 제29권2호
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• pp.301-309
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• 2022

Protective coatings are most widely used anticorrosive structures for steel structures. The corrosion under the coating damages the host material, but this damage is completely hidden. Therefore, a field-applicable under-coating-corrosion visualization method has been desired for a long time. Laser ultrasonic technology has been studied in various fields as an in situ nondestructive inspection method. In this study, a comparative analysis was carried out between a guided-wave ultrasonic propagation imager (UPI) and pulse-echo UPI, which have the potential to be used in the field of under-coating-corrosion management. Both guided-wave UPI and pulse-echo UPI were able to successfully visualize the corrosion. Regarding the field application, the guided-wave UPI performing Q-switch laser scanning and piezoelectric sensing by magnetic attachment exhibited advantages owing to the larger distance and incident angle in the laser measurement than those of the pulse-echo UPI. Regarding the corrosion visualization methods, the combination of adjacent wave subtraction and variable time window amplitude mapping (VTWAM) provided acceptable results for the guided-wave UPI, while VTWAM was sufficient for the pule-echo UPI. In addition, the capability of multiple sensing in a single channel of the guided-wave UPI could improve the field applicability as well as the relatively smaller size of the system. Thus, we propose a guided-wave UPI as a tool for under-coating-corrosion management.

• 대한방사선기술학회지:방사선기술과학
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• 제46권6호
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• pp.543-551
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• 2023

In this study, the aim was to assess the shielding performance of different 3D printing materials, specifically those produced using FDM, SLA, and CJP methods, with a focus on their application as shielding devices in clinical settings. Additionally, the weight of lead shielding materials can evoke reluctance in pediatric patients undergoing X-ray imaging. A total of 12 materials were printed using their respective 3D printers. These materials were then subjected to X-ray testing using diagnostic X-ray equipment and an exposure meter. The goal was to evaluate their shielding capabilities in comparison to 1 mm lead. The results of this evaluation revealed that VisiJet PXL-Pastel, produced using the CJP method, exhibited the highest shielding performance. Therefore, VisiJet PXL-Pastel by CJP method was selected for the creation of a shielding device designed for pediatric reproductive organs. Subsequent tests demonstrated that both the newly created shielding device and conventional lead shielding equipment achieved the same maximum shielding rate at 50 kVp. Specifically, the shielding rate for the 3D printed device was measured at 84.53%, while the conventional lead shielding equipment, categorized as Apron1 (85.74%), Apron2 (99.98%), and Apron3 (99.04%), demonstrated similar performance. In conclusion, the CJP-produced VisiJet PXL-Pastel material showcased excellent radiation shielding capabilities, allowing for anatomical observations of the target organs and their surrounding structures in X-ray images. Furthermore, its lower weight in comparison to traditional lead shielding materials makes it a clinically practical and useful choice, particularly for pediatric applications.

• Tribology and Lubricants
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• 제39권6호
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• pp.256-261
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• 2023

This study is conducted to evaluate the durability of superhydrophobic surfaces, with a focus on two aspects: contact angle measurement and self-cleaning-performance analysis. Superhydrophobic copper and aluminum surfaces are fabricated using the immersion method and subjected to a rolling wear test, in which a 2 kg weight is placed on a rolling tester, under loaded conditions. To evaluate their durability, the contact angles of the specimens are measured for each cycle. In addition, the surface deformation of the specimens before and after the test is analyzed through SEM imaging and EDS mapping. The degradation of the self-cleaning performance is evaluated before and after the wear test. The results show that superhydrophobic aluminum is approximately 4.5 times more durable than superhydrophobic copper; the copper and aluminum specimens could endure 21,000 and 4,300 cycles of wear, respectively. The results of the self-cleaning test demonstrate that superhydrophobic aluminum is superior to superhydrophobic copper. After the wear test, the self-cleaning rates of the copper and aluminum specimens decrease to 72.7% and 83.4%, respectively. The relatively minor decrease in the self-cleaning rate of the aluminum specimen, despite the large number of wear cycles, confirms that the superhydrophobic aluminum specimen is more durable than its copper counterpart. This study is expected to aid in evaluating the durability of superhydrophobic surfaces in the future owing to the advantage of performing wear tests on superhydrophobic surfaces without damaging the surface coating.

• 대한물리치료과학회지
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• 제31권1호
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• pp.88-97
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• 2024

Background: This study was to investigate effects of Correlation Analysis between Cervical-Vertebra Angle and Neck Range of Motion, Muscle Strength, Sternocleidomastoid Thickness of Patients with Forward Head Posture Design: Correlation Analysis. Methods: The subjects of this study were a total of 54 people in the forward head position and their ages were between 30 and 50 years old. The subjects cranio-vertebral angles, neck extension, neck flexion, neck rotation angles, neck flexor strength, neck extensor strength, sternocleidomastoid thickness were evaluated through measuring instruments. The thickness of the sternocleidomastoid muscle was measured using an imaging ultrasound diagnostic device (ultra sound, Versana Premier, GE Medical systems, China). CVA was measured by measuring the side photo of the subject was taken with a camera and evaluated.. neck joint range of motion was measured through digital inclinometer for extension, flexion, and neck rotation. neck muscle strength was measured by measuring the using a digital sthenometer. Data analysis in this study was statistically processed using SPSS version 26.0 (IBM SPSS Inc., USA). Correlation analysis was used and the statistical significance level was set at 0.05. Results: The results neck extension(r= 0.70^**), neck flexion(r= 0.67^**), neck rotation(r= 0.56^**), neck extensor muscle strengt(r= 0.85^**), neck flexor muscle strength(r= 0.66^**), sternocleidomastoid thicknes(r= -0.81^**) It indicates that there is a correlation. Conclusion:These results improve the Cervical-vertebra angle of patients with forward head posture should include a program to improve the thickness of the SCM. In the future, study can be used as an evidentiary material for treatment interventions to improve the Cervical-vertebra angle of patients with forward head posture.

• 지구물리와물리탐사
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• 제8권4호
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• pp.270-279
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• 2005

일본 문부과학성의 연구 지원하에 지뢰 탐지를 위한 GPR 시스템 개발에 관한 연구를 수행하였다. 2005 년도까지 두 종류의 새로운 지뢰탈지 GPR 시스템 원형의 개발을 완성하였으며 이를 ALIS (Advanced Landmine Imaging System)와 SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar)이라고 명명하였다. ALIS는 금속탐지기와 GPR을 결합한 새로운 형태의 휴대용 지뢰탐지 시스템이다. 센서의 위치를 실시간으로 추적하는 시스템을 장착하여 센서에 감지된 신호를 실시간으로 영상화할 수 있도록 하였으며, 센서 위치의 추적은 센서의 손잡이에 장착한 CCD 카메라만을 이용하여 가능하도록 고안하였다. 그리고 GPR과 금속탐지기 신호를 CCD 카메라에 포착된 영상에 중첩하여 동시에 영상화하도록 설계하였기 때문에 매설된 탐지 목적물을 용이하게 그리고 신뢰할 만한 수준으로 탐지하고 구별할 수 있다. 2004년 12월에 아프가니스탄에서 ALIS의 현장 검증 실험을 수행하였으며, 이를 통해 이 연구에서 개발한 시스템을 이용하여 매설된 대인지뢰를 탐지할 수 있을 뿐만 아니라 대인지뢰와 금속 파편의 구분 또한 가능함을 보였다. SAR-GPR은 이동 로보트에 장착한 지뢰탐지 시스템으로 GPR과 금속탐지기 센서로 구성된다. 다수의 송, 수신 안테나로 구성된 안테나 배열을 채택하여 개선된 신호처리 기법의 적용을 가능하며, 이를 통해 좀 더 나은 지하 영상의 획득이 가능하다. SAR-GPR에 합성개구 레이다 알고리듬을 채용함으로써 원하지 않는 클러터(clutter)신호를 억제하고 불균질도가 높은 매질 내부에 매설된 목적물을 영상화할 수 있다. SAR-GPR은 새로이 개발한 휴대용 벡터 네트워크 분석기를 이용한 스텝 주파수 레이다 시스템(stepped frequency radar system)으로 6 개의 Vivaldi 안테나와 3 개의 벡터 네트워크 분석기로 구성된다. SAR-GPR의 크기는 $30cm{\times}30cm{\times}30cm$, 중량은 17 kg 정도이며 소형 무인 차량의 로보트 팔에 장착된다. 이 시스템의 현장 적용 실험은 2005 년 3 월 일본에서 성공적으로 실시된 바 있다.

• Journal of Chest Surgery
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• 제43권6호
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• pp.700-704
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• 2010

배경: 최근 양전자단층촬영/전산화단층촬영(PET/CT) 검사가 점차 보편화 되어가고 있다. 림프절 병기 진단에 있어서 CT와 PET/CT의 유용성 및 실효성에 대해 알아보고자 하였다. 대상 및 방법: 2006년 1월부터 2009년 8월까지 본원에서 악성종양으로 폐절제술을 받은 110명의 환자 중, 술 전 본원에서 조영증강 흉부전산화단층촬영 (CT)과 전신 양전자단층촬영/전산화단층촬영 결합영상(PET/CT fusion imaging, integrated PET/CT) 검사를 모두 시행 받고, 술 후 원발성 비소세포폐암을 진단 받은 48명의 환자들을 대상으로 하였다. 림프절을 superior mediastinal nodes, aortic nodes, inferior mediastinal nodes, 그리고 Nl nodes의 4군으로 분류하여 CT와 PET/CT의 진단력에 대한 통계분석을 실시하였다. 결과: 4개의 군 가운데, inferior mediastinal nodes를 제외한 나머지 군들은 CT보다 PET/CT에서 민감도가 향상되는 소견을 보였다. 하지만 두 검사의 진단력 차이를 각각의 군에 대해 McNemar's test를 사용하여 분석한 결과 통계적으로 유의한 차이는 보이지 않았다(p-values; superior mediastinal nodes=0.109, aortic nodes=1.000, inferior mediastinal nodes=0.625, Nl nodes=0.424). 결론: 본 연구에서 종격동 림프절에 대한 PET/CT의 진단력은 조영증강 CT와 비슷한 정도로 나타났다. 현재 PET/CT는 CT와 상호보완적인 수단으로써 사용되어야 할 것으로 사료되며, 앞으로 촬영 기술 및 판독 수준이 더욱 발전하고 결과들이 많이 축적되었을 때에는 보다 좋은 성적을 보일 것으로 생각된다.