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( Deng Jun ),( Gong Xuehai ),( Gong Yinchun ),( Li Liguang ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-
Facing with the hydrogen energy era in future, the development of high-efficiency and zero-emissions of power system is a worldwide problem and challenge. As a potential way to achieve high-efficiency and zero-emissions, the main idea of argon cycled engine concept is to use hydrogen as fuel and pure oxygen as oxidant in the combustion cycle of traditional internal combustion engine, and use Ar (with the specific heat ratio of up to 1.67) as intake charge instead of N<sub>2</sub>. Argon cycled engine can substantially increase the theoretical thermal efficiency of traditional combustion engine and meanwhile avoid NOx emissions problem. Since N<sub>2</sub> is replaced with Ar, the in-cylinder ambient density increases, which makes the in-cylinder mixture process of the direct injected gas an outstanding problem. In this paper, studies on penetration length, cone angle, entrainment rate, under-expanded region and other characteristics of H<sub>2</sub> and O<sub>2</sub> injection into the Ar environment were conducted based on experimental method. Based on the high background pressure constant volume chamber and the high-speed camera system, the shape of gas jets under different conditions was studied by shadowing method. Maximum injection pressure is 10MPa. Maximum environment pressure is 1.2MPa.The experimental results show that increase of the injection pressure or the decrease of the environmental pressure leads to significant increases of the gas penetration length. Jet penetration length of O<sub>2</sub> is slightly lower than H<sub>2</sub> by 0-6%. The cone angle of the gas jet increases slightly with the increase of the injection pressure and the ambient pressure. Under all the experimental pressure boundary conditions, the H<sub>2</sub> jet cone angles are between 32 ° and 38 ° and the cone angles of the O<sub>2</sub> jet are between 22 ° and 28 °; The entrainment rate of the gas jet increases with increment of the injection pressure, the ambient pressure and the injection duration. Jet entrainment rate of O<sub>2</sub> is 2.43 to 2.98 times higher than H<sub>2</sub> jet.
등준걸(Jun Jie Deng),정홍인(Hong-In Cheng),고창성(Chang Seong Ko) 대한인간공학회 2021 대한인간공학회 학술대회논문집 Vol.2021 No.11
소형·소량의 운송물을 수탁하여 받는 사람의 주택, 사무실, 그 밖의 장소까지 운송하여 인도하는 것을 일반택배라고 한다. 택배업무에서 주요 작업은 화물분류작업(물류센터 작업), 차량운전, 집화·배송 등의 작업으로 이루어진다. 전세계의 택배 물량은 지속적으로 증가 추세에 있으며 특히 최근 코로나로 인해 급격하게 증가되었다. 국내의 택배업 종사자 수는 2019년 현재 약 6만명에 이르고 있고, 업체 간의 심한 경쟁과 낙후된 작업 환경 등으로 인해 2020년도에 16명의 택배 근로자가 과로사로 사망하였다. 2021년에는 생활물류서 비스산업발전법을 제정하기에 이르렀으나 택배 관련 인간공학적 연구는 미흡한 실정이다. 산업재해를 예방하고 업무의 효율성을 높이기 위해 안전한 택배 작업 방안을 마련하고 작업의 표준을 설정하는 것은 매우 필요하다. 이를 위해 택배와 연관된 인간공학 분야 연구에 관한 문헌 연구를 실시하였다. 이와 같은 연구를 통해 택배업무와 관련하여 이제까지 수행된 다양한 연구를 살펴보고 우리나라 택배와 관련해 추진해야 할 연구방향을 제시하고자 한다. 문헌연구는 국내외 학술 DB와 학위 논문들을 중심으로 수행하였으며 가능한 전반적인 인간공학 분야를 포함시키고자 하였다.
Preliminary Application of High-Definition CT Gemstone Spectral Imaging in Hand and Foot Tendons
Kai Deng,Cheng-Qi Zhang,Wei Li,Jun-Jun Wang,Xin-Yi Wang,Tao Pang,Guang-Li Wang,Cheng Liu 대한영상의학회 2012 Korean Journal of Radiology Vol.13 No.6
Objective: To assess the feasibility of visualizing hand and foot tendon anatomy and disorders by Gemstone Spectral Imaging (GSI) high-definition CT (HDCT). Materials and Methods: Thirty-five patients who suffered from hand or foot pain were scanned with GSI mode HDCT and MRI. Spectrum analysis was used to select the monochromatic images that provide the optimal contrast-to-noise ratio (CNR) for tendons. The image quality at the best selected monochromatic level and the conventional polychromatic images were compared. Tendon anatomy and disease were also analyzed at GSI and MRI. Results: The monochromatic images at about 65 keV (mean 65.09 ± 2.98) provided the optimal CNR for hand and foot tendons. The image quality at the optimal selected monochromatic level was superior to conventional polychromatic images (p = 0.005, p < 0.05). GSI was useful in visualizing hand and foot tendon anatomy and disorders. There were no statistical differences between GSI and MRI with regard to tendon thickening (χ2 = 0, p > 0.05), compression (χ2 = 0.5, p > 0.05), absence (χ2 = 0, p > 0.05) and rupture (χ2 = 0, p > 0.05). GSI was significantly less sensitive than MRI in displaying tendon adhesion (χ2 = 4.17, p < 0.05), degeneration (χ2 = 4.17, p < 0.05), and tendinous sheath disease (χ2 = 10.08, p < 0.05). Conclusion: GSI with monochromatic images at 65 keV displays clearly the most hand and foot tendon anatomy and disorders with image quality improved, as compared with conventional polychromatic images. It may be used solely or combined with MRI in clinical work, depending on individual patient disease condition. Objective: To assess the feasibility of visualizing hand and foot tendon anatomy and disorders by Gemstone Spectral Imaging (GSI) high-definition CT (HDCT). Materials and Methods: Thirty-five patients who suffered from hand or foot pain were scanned with GSI mode HDCT and MRI. Spectrum analysis was used to select the monochromatic images that provide the optimal contrast-to-noise ratio (CNR) for tendons. The image quality at the best selected monochromatic level and the conventional polychromatic images were compared. Tendon anatomy and disease were also analyzed at GSI and MRI. Results: The monochromatic images at about 65 keV (mean 65.09 ± 2.98) provided the optimal CNR for hand and foot tendons. The image quality at the optimal selected monochromatic level was superior to conventional polychromatic images (p = 0.005, p < 0.05). GSI was useful in visualizing hand and foot tendon anatomy and disorders. There were no statistical differences between GSI and MRI with regard to tendon thickening (χ2 = 0, p > 0.05), compression (χ2 = 0.5, p > 0.05), absence (χ2 = 0, p > 0.05) and rupture (χ2 = 0, p > 0.05). GSI was significantly less sensitive than MRI in displaying tendon adhesion (χ2 = 4.17, p < 0.05), degeneration (χ2 = 4.17, p < 0.05), and tendinous sheath disease (χ2 = 10.08, p < 0.05). Conclusion: GSI with monochromatic images at 65 keV displays clearly the most hand and foot tendon anatomy and disorders with image quality improved, as compared with conventional polychromatic images. It may be used solely or combined with MRI in clinical work, depending on individual patient disease condition.
An Optimized Motion Estimation Algorithm and Application in the FRUC System
Min-Jun Deng,Ping Gan,Zhuo Chen,Xiao-Qing Shen,Dong-Lian Li,Ming-Yan Yu,Yu Zhang,Cai -Lan Zeng,He Huang 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.8
Based on the optimized three-step search algorithm. Combining threshold judgment as well as local full search, a more efficient motion estimation algorithm is proposed. The algorithm not only inherited the traditional three-step algorithm’s quick speed but also kept the advantages of a relatively small amount of calculation, besides it can avoid the local optimum problem in the three-step search algorithm (TSS). In addition, the algorithm combined with the threshold judgment and local full search algorithm, so it also maintains satisfactory visual quality. Comparing the algorithm with TSS and local full search algorithm (LFS). The algorithm has great performance in search points and peak signal-to-noise ratio. Experimental results show that compared with LFS, search points drop by 34.61% ~ 54.47% .While compared with the TSS, the search points only rise by 6.15% ~ 12.21%. The average PSNR of proposed Algorithm is 0.24dB higher than LFS and 3.30dB higher than TSS.