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Adsorption and sensing characteristics of insulating gas C4F7N on 3d late transition metal-phthalocyanine:Theoretical and experimental study

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High Voltage 2024年第4期9卷 870-878页

作者： Dachang Chen Ziang Zheng Cong Zhang Yi Luo Song Xiao Qing Miao Ke Liu Beibei Xiao school of electrical and Electronic engineering Wuhan Polytechnic UniversityWuhanChina Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijingChina school of electrical engineering and Automation Wuhan UniversityWuhanChina school of Energy and Power engineering Jiangsu University of Science and TechnologyZhenjiangChina

Heptafluoroisobutyronitrile(C_(4)F_(7)N)is being considered as a promising alternative to the greenhouse gas SF6 in the electrical ***,its biotoxicity necessitates the development of gas sensing technology to detect leaked C_(4)F_(7)N.A combination of density functional theory and experiments was employed to evaluate the adsorption and sensing performance of different metal-phthalocyanines as potential sensing materials for C_(4)F_(7)N *** study included exploring adsorption configurations with adsorption energies,electron transfer,and adsorption distance,as well as comparisons of electronic properties,electron distribution,and density of states(DOS)among the ***,gas sensing experiments were conducted using different MPcs to detect 25-100 ppm C_(4)F_(7)*** results revealed that Mn-Pc,Fe-Pc,Co-Pc,and Zn-Pc exhibited considerable chemical interactions,while Ni-Pc and Cu-Pc showed weaker adsorption *** findings were further elucidated based on the electron density and DOS of atomic ***,gas sensing experiments indicated that Co-Pc demonstrated a higher response compared to Fe-Pc at the same concentration of C_(4)F_(7)***,the theoretical and experimental insights offer valuable guidance for C_(4)F_(7)N detection and provide a systematic approach to screen and explore organometallic polymer-based gas sensors applicable in various fields.

关键词： adsorption phthalocyanine Adsorption

Effect of low-speed waterjet pressure on the rock-breaking performance of unsubmerged cavitating abrasive waterjet

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Petroleum Science 2024年第4期21卷 2638-2649页

作者： Chen-Xing Fan Deng Li Yong Kang Hai-Tao Zhang Hubei Key Laboratory of Waterjet Theory and New technology Wuhan University school of Power and mechanical engineering Wuhan University

Unsubmerged cavitating abrasive waterjet(UCAWJ) has been shown to artificially create a submerged environment that produces shear cavitation, which effectively enhances rock-breaking performance. The shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed waterjet. However, the effect of the pressure of the coaxial low-speed waterjet is pending. For this purpose, the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated,and the effects of erosion time and ruby nozzle diameter on erosion performance were discussed. Finally,the micromorphology of the sandstone was observed at different locations. The results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking performance. At different standoff distances, the mass loss increases first and then decreases with the increase of low-speed waterjet pressure, the maximum mass loss is 10.4 g at a low-speed waterjet pressure of0.09 MPa. The surface morphology of cavitation erosion was measured using a 3D profiler, the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation collapse. At a low-speed waterjet pressure of 0.18 MPa, the cavitation erosion surface depth can reach 600 μm with a roughness of 127 μm.

关键词： Rock-breaking Coaxial low-speed waterjet pressure Abrasive waterjet Cavitation Unsubmerged environment

Observation of an upward lightning flash with 21 upward positive leaders initiated from different wind turbines in wind farm

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High Voltage 2024年第1期9卷 163-171页

作者： Li Cai Yifeng Ke Wenchao Fan Ruisheng Yan Mi Zhou Jianguo Wang Yadong Fan engineering Research Center of Ministry of Education for Lightning Protection and Grounding technology School of Electrical Engineering and AutomationWuhan UniversityWuhanChina

As the wind turbine height increases,the probability of multiple upward leaders flashes within the wind farm *** this study,an upward lightning flash containing 21 upward positive leaders(UPLs)initiated from different wind turbines in Zhangbei Wind Farm was *** average speed of the UPLs was 1.2×10^(5) m/s,which mostly decreased to zero before reaching the cloud *** four UPLs developed to cloud height,with prolonged periods of bright light on three of them and with a minimum duration of 126 ms.A total of nine return strokes occurred on the other two dissipated leader channels,and the numbers of strokes on the two channels was six and three,*** average interstroke interval for the return strokes was 10.5 *** of these nine return strokes had peak currents smaller than 10 *** high-speed video frames confirmed that competition does exist between the UPLs,and the range of shielding effects increases as the height of the ULs *** effect of fan rotation on the initiation of upward leaders and the shielding effect between the wind turbines and upward leaders are discussed.

关键词： flash return initiated

Weakly supervised point cloud segmentation via deep morphological semantic information embedding

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CAAI Transactions on Intelligence technology 2024年第3期9卷 695-708页

作者： Wenhao Xue Yang Yang Lei Li Zhongling Huang Xinggang Wang Junwei Han Dingwen Zhang school of Automation Northwestern Polytechnical UniversityXi'anChina institute of mechanical and electrical engineering BeijingChina school of Electronic Information and Communications Huazhong University of Science and TechnologyWuhanChina

Segmenting the semantic regions of point clouds is a crucial step for intelligent agents to understand 3D *** supervised point cloud segmentation is highly desirable because entirely labelling point clouds is highly time-consuming and *** the low-costing labelling of 3D point clouds,the scene-level label is one of the most effortless label ***,due to the limitation of classifier discriminative capability and the orderless and structurless nature of the point cloud data,existing scene-level method is hard to transfer the semantic information,which usually leads to the under-activated or over-activated *** this end,a local semantic embedding network is introduced to learn local structural patterns and semantic ***,the proposed network contains graph convolution-based dilation and erosion embedding modules to implement‘inside-out’and‘outside-in’semantic information dissemination ***,the proposed weakly supervised learning framework could achieve the mutual propagation of semantic information in the foreground and *** experiments on the widely used ScanNet benchmark demonstrate the superior capacity of the proposed approach when compared to the current alternatives and baseline models.

关键词： artificial intelligence computer vision deep learning

Impacts of multi-foulings on salinity gradient energy conversion process in negatively charged conical nanochannels

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Science China(Technological Sciences) 2024年第6期67卷 1714-1726页

作者： MAO RuiJie CHEN Xi ZHOU RuHong LONG Rui LIU ZhiChun LIU Wei school of Energy and Power engineering Huazhong University of Science and TechnologyWuhan430074China China-EU institute for Clean and Renewable Energy Huazhong University of Science and TechnologyWuhan430074China school of mechanical Science and engineering Huazhong University of Science and TechnologyWuhan430074China

Membrane fouling inevitably occurs during nanofluidic reverse ***,the impact of multi-fouling on the energy conversion performance of negatively charged conical nanochannels under asymmetrical configurations is systematically *** results reveal that in Configuration I,where a high-concentration solution is applied at the tip side,at small concentration ratios,multiple foulings reduce the electric *** Configuration II,where a low-concentration solution is applied at the tip side,multiple foulings near the base side contribute to the electric *** fouling that formed near the lowconcentration entrance diminished the electric power and energy conversion ***-fouling lowered the electrical power consumption by 69.27%and 99.94%in Configurations I and II,*** Configuration I,the electric power first increased with increasing fouling surface charge density,reached its maximum value,and thereafter *** Configuration II,the electric power first decreased with increasing fouling surface charge density,reached its minimum value,and thereafter *** negative or positive charge densities of fouling contribute to the electric power and energy conversion efficiency.

关键词： conical nanochannel fouling nanofluidic reverse electrodialysis salinity gradient energy

Cyclic Pulsating Pressure Enhanced Segregating Structuration of Ultra-High Molecular Weight Polyethylene/Graphene Composites as High-performance Light-Weight EMI Shields

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Chinese Journal of Polymer Science 2024年第7期42卷 958-967,I0008页

作者： Yun-Zhi Huang Xiao-Xiao Liu Lan-Wei Li Guang-Ming Huang Zhao-Xia Huang Jin-Ping Qu National engineering Research Center of Novel Equipment for Polymer Processing Key Laboratory of Polymer Processing EngineeringMinistry of EducationGuangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced ManufacturingSchool of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou 510641China school of Advanced Manufacturing technology Guangdong Mechanical&Electrical PolytechnicGuangzhou 510550China

Currently,the enhancement in electromagnetic interference(EMI)performance of polymeric composite generally relies on either improving electrical conductivity(σ)for stronger electromagnetic(EM)reflections or tailoring structure for higher EM ***,we proposed a novel technique called cyclic pulsating pressure enhanced segregating structuration(CPP-SS),which can reinforce these two factors *** structural information was supplied by optical microscopy(OM)and scanning electron microscopy(SEM),both of which confirmed the formation and evolution of segregate structured ultra-high molecular weight polyethylene(UHMWPE)/graphene ***,the result showed that CPP-SS can significantly improve theσof ***,advanced specific EMI shielding efficiency of 31.1 d B/mm was achieved for UHMWPE/graphene composite at 1-mm thickness and a low graphene loading of 5 wt%.Meanwhile,it also confirmed that the intrinsic disadvantage of poor mechanical properties of conventional segregated structure composites can be *** work is believed to provide a fundamental understanding of the structural and performance evolutions of segregated structured composites prepared under CPPSS,and to bring us a simple and efficient approach for fabricating high-performance,strong and light-weight polymeric EMI shields.

关键词： Cyclic pulsating pressure Segregated structure Ultra-high molecular weight polyethylene Graphene Electromagnetic interface

Fault diagnosis of HVAC system with imbalanced data using multi-scale convolution composite neural network

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Building Simulation 2024年第3期17卷 371-386页

作者： Rouhui Wu Yizhu Ren Mengying Tan Lei Nie school of mechanical engineering Hubei University of TechnologyWuhan430068China Industrial Research institute of Xiangyang Hubei University of technology Xiangyang441100China

Accurate fault diagnosis of heating,ventilation,and air conditioning(HVAC)systems is of significant importance for maintaining normal operation,reducing energy consumption,and minimizing maintenance ***,in practical applications,it is challenging to obtain sufficient fault data for HVAC systems,leading to imbalanced data,where the number of fault samples is much smaller than that of normal ***,most existing HVAC system fault diagnosis methods heavily rely on balanced training sets to achieve high fault diagnosis ***,to address this issue,a composite neural network fault diagnosis model is proposed,which combines SMOTETomek,multi-scale one-dimensional convolutional neural networks(M1DCNN),and support vector machine(SVM).This method first utilizes SMOTETomek to augment the minority class samples in the imbalanced dataset,achieving a balanced number of faulty and normal ***,it employs the M1DCNN model to extract feature information from the augmented ***,it replaces the original Softmax classifier with an SVM classifier for classification,thus enhancing the fault diagnosis *** the SMOTETomek-M1DCNN-SVM method,we conducted fault diagnosis validation on both the ASHRAE RP-1043 dataset and experimental dataset with an imbalance ratio of 1:*** results demonstrate the superiority of this approach,providing a novel and promising solution for intelligent building management,with accuracy and F1 scores of 98.45%and 100%for the RP-1043 dataset and experimental dataset,respectively.

关键词： fault diagnosis chiller imbalanced data SMOTETomek multi-scale neural networks

Optimal Stochastic Scheduling Strategy of Multi-vector Energy Complex Integrated with Full-blown Power-to-biomethane Model

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 863-873页

作者： Guanwei Zeng Chengxi Liu Minfang Liao Yongjian Luo Xuzhu Dong Hubei engineering and technology Research Center for AC/DC Intelligent Distribution Network WuhanChina the school of electrical engineering and Automation Wuhan UniversityWuhanChina

We propose an optimal stochastic scheduling strategy for a multi-vector energy complex(MEC),considering a fullblown model of the power-to-biomethane(Pt M)*** conventional optimization that uses a simple efficiency coefficient to coarsely model energy conversion between electricity and biomethane,a detailed Pt M model is introduced to emphasize the reactor kinetics and chemical equilibria of *** model crystallizes the interactions between the Pt M process and MEC flexibility,allowing to adjust the operating condition of the methanation reactor for optimal MEC operation in stochastic *** optimization and flowsheet design of the Pt M process increase the average selectivity of methane(i.e.,ratio between net biomethane production and hydrogen consumption)up to 83.7%in the proposed synthesis *** results can provide information and predictions to operators about the optimal operating conditions of a Pt M unit while improving the MEC flexibility.

关键词： Multi-vector energy complex optimal stochastic scheduling power-to-biomethane unit process synthesis natural gas

Investigation of wake-induced vibration interference between two staggered wave-cone cylinders at subcritical Reynolds number

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Journal of Hydrodynamics 2024年第2期36卷 378-393页

作者： Lin Zou Di-wei Liu Jian Liu Hong-cheng Zuo Yin-huan Zheng Hao Xia school of mechanical and Electronic engineering Wuhan University of TechnologyWuhan430070China Department of Aeronautical and Automotive engineering Loughborough UniversityLoughboroughUK

The wake induced vibration(WIV)of a one-and two-degree-of-freedom(1DOF,2DOF)downstream wave-cone cylinder(WCC)behind a stationary equal-size upstream wave-cone cylinder in the staggered arrangement is numerically investigated at subcritical Reynolds number of 3900 by using shear stressed transfer(SST)k-ωturbulence *** streamwise pitch ratios(P/Dm)vary from 4 to 6 with a fixed incident angleα=8°.Experimental measurements were also performed for the validation of the present numerical *** is found that the largest vibration amplitude in crossflow direction occurred at P/Dm=4,Ur=8 with small difference of streamwise vibration at P/Dm=4,*** from single wavy-cone cylinder(SWCC),the downstream flexible one of a pair staggered WCCs got larger vibration amplitude during phase switching stage instead of in-phase *** upstream wake will suppress the triple frequency of main frequency in the power spectra density(PSD)functions of Cl but stimulate the double one of *** intriguing vibration mechanism happened in all 2DOF cases where the trajectory of downstream WCC is a significant ellipse rather than a figure of *** transformation of phase switching and the variation of the main frequency of drag coefficient(Cd)can be explained by the vortex-shedding modes of downstream WCC.

关键词： Two wave-cone cylinders staggered arrangement wake induced vibration phase switching vortex shedding