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VEHICLE-LEVEL ELECTROMAGNETIC COMPATIBILITY PREDICTION BASED ON MULTI-PORT NETWORK THEORY
Feng Gao,Hanzhe Dai,Jiawei Qi,Zilong Wang 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.6
This paper proposes a new methodology based on the multi-port network theory to predict the vehicle-level electromagnetic compatibility performance. The original EMC problem is firstly converted to a network by separating the electrical large structures and electrical small components. The impedance is proposed to describe the coupling process of network to eliminate the influence of port impedance on network. Based on this network model, the relationship between the exciting sources and the sensitive components is set up using the multi-port network theory. Furthermore, some application problems, such as measurement of parameters, are also discussed. After validated by a bench test, this methodology for vehicle level electromagnetic compatibility was further applied to predict and improve the low frequency radiated emission of an electric vehicle. The application results show that it can be used to predict electromagnetic interference and analyze the main exciting source satisfactorily.
Jiawei Yu,Songlin Zheng,Jinzhi Feng,Lihui Zhao 한국자동차공학회 2017 International journal of automotive technology Vol.18 No.3
The generation of valid and effective test spectra from proving ground recorded load spectra is critical for automotive durability testing. Traditional methods mostly based on spectrum damage were used to select load spectra. Statistical characteristics of load spectra were taken into account, and a new load spectra determination method based on a concatenation of a multi-section minimum standard deviation spectrum (CMSD) was proposed. The CMSD spectra were created and based on proving ground recorded load spectra. Fatigue damage analyses showed that the CMSD spectra approximated the mean damage spectra and were representative of proving ground load spectra. Subsequently, the CMSD spectra were edited by applying the time correlated fatigue damage (TCFD) analysis method to generate accelerated loading spectra. The spectra editing process of the TCFD was discussed in detail. Validation of the accelerated spectra was conducted from amplitude and frequency domains. The same fatigue damage and identical spectrum properties were retained in the accelerated spectra. A vehicle 4-post testing was finally conducted where the accelerated loading spectra were applied as the target spectra. Several fatigue fracture phenomena occurred during our test, which showed good agreement with the field test. Therefore, the load spectra determination method CMSD associated with the load spectra editing method TCFD were demonstrated reasonable and practical.
Buckling and vibrational information of an annular nanosystem covered with piezoelectric layer
Gao, Jie,Nie, Rong,Feng, Yongyi,Luo, Jiawei,Li, Siyu Techno-Press 2022 Advances in nano research Vol.13 No.3
Resently, the use of smart structures has been heightened up rapidly. For this issue, vibration analysis related to a graphene nanoplatelet composite (GPLRC) nanodisk which is attached to a piezoelectric layer and is subjected to thermal loads is explored in the current paper. The formulation of this study is obtained through the energy method and nonlocal strain gradient theory, and then it is solved employing generalized differential quadrature method (GDQM). Halpin-Tsai model in addition to the mixture's rule are utilized to capture the material properties related to the reinforced composite layer. The compatibility conditions are presented for exhibiting the perfect bounding between two layers. The results of this study are validated by employing the other published articles. The impact of such parameters as external voltage, the radius ratio, temperature difference, and nonlocality on the vibrational frequency of the system is investigated in detail.
Crack detection in concrete slabs by graph-based anomalies calculation
Yuqing Zhou,Weifang Sun,Jiawei Xiang,Binqiang Chen,Wei Feng 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.29 No.3
Concrete slab cracks monitoring of modern high-speed railway is important for safety and reliability of train operation, to prevent catastrophic failure, and to reduce maintenance costs. This paper proposes a curvature filtering improved crack detection method in concrete slabs of high-speed railway via graph-based anomalies calculation. Firstly, large curvature information contained in the images is extracted for the crack identification based on an improved curvature filtering method. Secondly, a graph-based model is developed for the image sub-blocks anomalies calculation where the baseline of the subblocks is acquired by crack-free samples. Once the anomaly is large than the acquired baseline, the sub-block is considered as crack-contained block. The experimental results indicate that the proposed method performs better than convolutional neural network method even under different curvature structures and illumination conditions. This work therefore provides a useful tool for concrete slabs crack detection and is broadly applicable to variety of infrastructure systems.
Yating Peng,Peng Wang,Jiawei Li,Jiajia Wu,Feng Lin,Dun Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-
Underwater optical instruments are commonly plagued by biofouling. As one of the most useful antifoulingstrategies, electrochemical chlorination is able to prevent biofouling efficiently, but the limited activityand selectivity in chlorine evolution reaction (CER) restrict its practical applications. To address thisproblem, we focus on the optimization of CER performance of cobalt-based catalysts. In this work, weprepared Co(OH)2 with different forms, morphologies, and intercalations. By adopting linear sweepvoltammetry and electrochemical active surface area analysis, it is demonstrated that the a-Co(OH)2exhibits better CER performance than b-Co(OH)2 does, and the manipulation of a-Co(OH)2 morphologycan help to further enhance CER performance. Meanwhile, the intercalation of a-Co(OH)2 plays a minorrole in the CER. Furthermore, based on the screened synthetic condition, the optimized a-Co(OH)2 wasapplied for practical antifouling examination, and its excellent antifouling ability was verified by theinvestigation on bacteria attachment and glass transmittance. The findings in this work not only enrichour understanding on the effects of synthetic conditions on CER performance of cobalt-based catalysts,but also provide useful insights into the development of electrochemical antifouling strategies.
Closed T-Spline Surface Reconstruction from Medical Image Data
Ce Shang,Jianzhong Fu,Zhiwei Lin,Jiawei Feng,Bin Li 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.11
The reconstruction from medical image data to CAD model is an essential process of Bio-medical engineering. So far, it is still challenging to create medical model which is suitable for both design and manufacturing. This paper introduces a process of constructing a single-patched closed T-spline surface model based on medical image data. The image data is first converted into triangular mesh and then parameterized onto a rectangular domain. An iterative least-squares fitting process is proposed to finally obtain the T-spline surface model with a user-specified tolerance. In this fitting process, the smoothing part of the algorithm is redesigned, considering the flexible structure of T-mesh and the geometric complexity of the T-spline surface. Local smoothness weighting factors are introduced to the fitting formula to locally adjust the smoothness of the surface. An adaptive smoothness checking points distribution method is proposed to reduce the computational cost. These algorithms are easy to implement and the obtained model is simple in form. Compared with the STL and NURBS model, the T-spline surface model requires less storage space and can be easily modified. The obtained model is suitable for Bio-medical engineering applications like bone scaffolds design, surgical planning and related manufacturing process.
He, Bangxiang,Hou, Lulu,Zhang, Feng,Cong, Xiaomei,Wang, Zhendong,Guo, Yalin,Shi, Jiawei,Jiang, Ming,Zhang, Xuecheng,Zang, Xiaonan The Korean Society of Phycology 2020 ALGAE Vol.35 No.3
Haematococcus pluvialis is a commercial microalga that can produce high quantities of astaxanthin. Under induced conditions, some important changes in the subcellular structures related to astaxanthin accumulation were observable. For example, a large number of astaxanthin granules, oil structures and starch granules appeared in the thick-walled cells; Astaxanthin granules gradually dissolved into the oil structures and spread throughout the entire cell with the fusion and diffusion process of oil structures during the middle and late stages of induction; The plastoglobules were closed to the newly formed structures, and some plastoglobules would abnormally increase in size under stress. Based on observations of cell damage, the degradation of membrane structures, such as chloroplasts, was found to be the primary form of damage during the early stage of induction. During the middle stage of induction, some transparent holes were exposed in the dissolving astaxanthin granules in the cytoplasm. In thick-walled cells, these transparent holes were covered by oil substances dissolving astaxanthin, thereby avoiding further damage to cells. Given the relatively few oil structures, in non-thick-walled cells, the transparent holes expanded to form multiple transparent areas, eventually resulting in the rupture and death of cells. These results suggested that the high level of synthesis and the wide range diffusion of oil explained the expansion of astaxanthin in H. pluvialis.
Ergonomic Development and Evaluation of UI Design for Optical Brain- Machine Interface (OBMI) System
Xin Cui(최신아),Hayoung Jung(정하영),Halim Kim(김하림),Yang Xiaopeng(양샤오펑),Linqing Feng(펭린칭),Shaomin Zhang(장샤오민),Mingkang Li(리밍캉),Changhao Liu(리우창하오),Jiawei Han(한지아웨이),Ruixue Wang(왕루이수에),Heecheon You(유희천) 대한인간공학회 2020 대한인간공학회 학술대회논문집 Vol.2020 No.10
Yudong Shi,Wei Li,Changhao Chen,Xiaoping Yuan,Yingying Yang,Song Wang,Zhiwei Liu,Feng Geng,Jiawei Wang,Xiangfen Luo,Xiangwang Wen,Lei Xia,Huanzhong Liu 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.11
Objective Excessive daytime sleepiness (EDS) and insomnia symptoms are common in patients with major depressive disorder (MDD), which might lead to a poor prognosis and an increased risk of depression relapse. The current study aimed to investigate the prevalence, and sociodemographic and clinical correlates of EDS and insomnia symptoms among adolescents with MDD.Methods The sample of this cross-sectional study included 297 adolescents (mean age=15.26 years; range=12–18 years; 218 females) with MDD recruited from three general and four psychiatric hospitals in five cities (Hefei, Bengbu, Fuyang, Suzhou, and Ma’anshan) in Anhui Province, China between January and August, 2021. EDS and insomnia symptoms, and clinical severity of depressive symptoms were assessed using Epworth sleepiness scale, Insomnia Severity Index, and Clinical Global Impression-Severity.Results The prevalence of EDS and insomnia symptoms in adolescents with MDD was 39.7% and 38.0%, respectively. Binary logistic regression analyses showed that EDS symptoms were significantly associated with higher body mass index (odds ratio [OR]=1.097, 95% confidence interval [CI]=1.027–1.172), more severe depressive symptoms (OR=1.313, 95% CI=1.028–1.679), and selective serotonin reuptake inhibitors use (OR=2.078, 95% CI=1.199–3.601). And insomnia symptoms were positively associated with female sex (OR=1.955, 95% CI=1.052–3.633), suicide attempts (OR=1.765, 95% CI=1.037–3.005), more severe depressive symptoms (OR=2.031, 95% CI=1.523–2.709), and negatively associated with antipsychotics use (OR=0.433, 95% CI=0.196–0.952).Conclusion EDS and insomnia symptoms are common among adolescents with MDD. Considering their negative effects on the clinical prognosis, regular screening and clinical managements should be developed for this patient population.