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Nondestructive Early Detection of Bruising in Pear Fruit Using Optical Coherence Tomography
Yang Zhou,Jianwei Mao,Di Wu,Tiebing Liu,Yun Zhao,Wujie Zhou,Zhengwei Chen,Fangni Chen 한국원예학회 2019 원예과학기술지 Vol.37 No.1
Pear fruit is susceptible to mechanical injury during harvesting, packaging, and transportation. Optical coherence tomography (OCT) can provide information concerning chemical and microstructural changes of fruit tissues. Therefore, using OCT to evaluate fruit quality is of great significance. In this study, OCT was used for early detection of subtle bruise symptoms underneath the pear peel. First, the signal intensity versus depth in relation to the OCT images of fruit tissue was determined, which was derived from the values of the OCT signal slope (OCTSS) and 1/e light penetration depth (D1/e). Furthermore, shaping (α) and scaling (β) indices were estimated by fitting a gamma distribution function to the signal intensity profile. After mechanical injury, OCTSS, α, and β decreased and the D1/e value increased. Distribution analysis of the relationship between α versus β served as an effective method to identify tissue bruising at an early stage. In conclusion, the results suggest that OCTSS, D1/e, and the α versus β distribution are closely correlated with bruise injury in pear fruit tissues. Thus, OCT is a promising technology for early and nondestructive bruise detection.
Lei Zhou,Tanghong Liu,Zhengwei Chen,Wenhui Li,Zijian Guo,Xuhui He,You-Wu Wang 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.32 No.6
This paper studied the case of high-speed train running from flat ground to bridges and into/out of tunnels, with or without crosswind based on the Computational Fluid Dynamics (CFD) method. First, the flow structure was analyzed to explain the influence mechanisms of different infrastructures on the aerodynamic characteristics of the train. Then, the evolution of aerodynamic forces of the train during the entire process was analyzed and compared. Additionally, the pressure variation on the train body and the tunnel wall was examined in detail. The results showed that the pressure coefficient and the flow structure on both sides of the high-speed train were symmetrical for no crosswind case. By contrast, under crosswind, there was a tremendous and immediate change in the pressure mapping and flow structure when the train passing through the bridge-tunnel section. The influence of the ground-bridge transition on the aerodynamic forces was much smaller than that of the bridge-tunnel section. Moreover, the variation of aerodynamic load during the process of entering and exiting the bridge-tunnel sections was both significant. In addition, in the case without crosswind, the change in the pressure change in the tunnel conformed to the law of pressure wave propagation, while under crosswind, the variation in pressure was comprehensively affected by both the train and crosswind in the tunnel.
Yang Zhou,Longjie Shi,Gang Ceng,Tiebing Liu,Yang Shi,Zhengwei Chen,Fenglin Wang,Yuefeng Ceng 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.3
The thickness of glaze is one of the important indicators in the quality evaluation of Longquan celadon. But till now, there isno automatic and non-destructive method to measure it. In order to satisfy this demand, an automated method has beenproposed to measure the glaze thickness based on optical coherence tomography (OCT) technique. According to themorphological characteristics of celadon glaze in OCT image, the proposed method locates the upper and lower boundariesof the glaze layer, then the glaze thickness is automatically calculated after the axial resolution calibration of the OCT imagesfor different categories of Longquan celadon. In the experiment, the glaze OCT images of 6 different categories of Longquanceladon were applied in the glaze thickness estimation. By comparing with the physical measuring result, this method is provedto be able to measure the glaze thickness rapidly and non-destructively and the performance is enough to meet the demandof the industrial application.
Recent Advances in Cardiac Magnetic Resonance Imaging
Sang-Eun Lee,Christopher Nguyen,Yibin Xie,Zixin Deng,Zhengwei Zhou,Debiao Li,장혁재 대한심장학회 2019 Korean Circulation Journal Vol.49 No.2
Cardiac magnetic resonance (CMR) imaging provides accurate anatomic information and advanced soft contrast, making it the reference standard for assessing cardiac volumes and systolic function. In this review, we summarize the recent advances in CMR sequences. New technical development has widened the use of CMR imaging beyond the simple characterization of myocardial scars and assessment of contractility. These novel CMR sequences offer comprehensive assessments of coronary plaque characterization, myocardial fiber orientation, and even metabolic activity, and they can be readily applied in clinical settings. CMR imaging is able to provide new insights into understanding the pathophysiologic process of underlying cardiac disease, and it can help physicians choose the best treatment strategies. Although several limitations, including the high cost and time-consuming process, have limited the widespread clinical use of CMR imaging so far, recent advances in software and hardware technologies have made the future more promising.