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Energy Harvesting in the Wake of An Inverted C-Shaped Bluff Body

China Ocean Engineering 2024年第1期38卷 68-80页

作者： WANG Jun-lei LI Shen-fang Md.Mahbub ALAM ZHU hong-jun HU Guo-biao School of Mechanical and Power Engineering Zhengzhou UniversityZhengzhou 450000China Center for Turbulence Control Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China Internet of Things Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China

This paper proposes a novel wake-induced vibration(WIV)-based energy harvesting system consisting of two bluff *** inverted C-shaped bluff body is stationary installed at the upstream position to generate an interference wake street,and a cylinder bluff body equipped with a transducer is elastically suspended at the downstream position to harness WIV *** hydrodynamics and energy harvesting(EH)performance of the proposed system are investigated via experimental *** reduced velocity(U*)ranging from 2 to 14(the corresponding Reynolds number ranging from 15100 to 106200)is considered in the present *** is found that the wake generated by the inverted C-shaped bluff body significantly affects the EH *** the opening angle(α)of the C-shaped bluff body increases the vibration amplitude of the downstream cylinder,thereby increasing the harvested *** the spacing(L)between two bluff bodies is two times the cylinder diameter(D),the wake-induced vibration(WIV)mode is observed,while the combined WIV and wake galloping(WG)mode occurs whenαis 150°,and L equals 3D or *** average drag coefficient becomes negative when L is 2D,3D,or *** carefully configuring a C-shaped bluff body,the wake generated by it can bring an augmenting effect on the vibration of the downstream EH *** example,the RMS power output of the proposed EH system reaches a maximum of 0.31 W at U*=8 and L=4D,which is 300%greater than that of its traditional ***,after a number of case stud-ies,it is identified that the proposed EH system can achieve the best performance whenαis 150°and L=2D.

关键词： wake-induced vibration vortex-induced vibration galloping energy harvesting bluff body

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3D near-surface P-wave velocity structure imaging with Distributed Acoustic Sensing and electric hammer source

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Earthquake Research Advances 2024年第3期4卷 27-33页

作者： Heting hong Fu Yin Yuhang Lei Yulan Li Baoshan Wang Deep Space Exploration Laboratory University of Science and Technology of ChinaHefei230026China School of Earth and Space Sciences University of Science and Technology of ChinaHefei230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei230026China

Distributed Acoustic Sensing(DAS) is an emerging technique for ultra-dense seismic observation, which provides a new method for high-resolution sub-surface seismic imaging. Recently a large number of linear DAS arrays have been used for two-dimensional S-wave near-surface imaging in urban areas. In order to explore the feasibility of three-dimensional(3D) structure imaging using a DAS array, we carried out an active source experiment at the Beijing National Earth Observatory. We deployed a 1 km optical cable in a rectangular shape, and the optical cable was recast into 250 sensors with a channel spacing of 4 m. The DAS array clearly recorded the P, S and surface waves generated by a hammer source. The first-arrival P wave travel times were first picked with a ShortTerm Average/Long-Term Average(STA/LTA) method and further manually checked. The P-wave signals recorded by the DAS are consistent with those recorded by the horizontal components of short-period seismometers. At shorter source-receiver distances, the picked P-wave arrivals from the DAS recording are consistent with vertical component recordings of seismometers, but they clearly lag behind the latter at greater *** is likely due to a combination of the signal-to-noise ratio and the polarization of the incoming wave. Then,we used the Tomo DD software to invert the 3D P-wave velocity structure for the uppermost 50 m with a resolution of 10 m. The inverted P-wave velocity structures agree well with the S-wave velocity structure previously obtained through ambient noise tomography. Our study indicates the feasibility of 3D near-surface imaging with the active source and DAS array. However, the inverted absolute velocity values at large depths may be biased due to potential time shifts between the DAS recording and seismometer at large source-receiver distances.

关键词： Distributed Acoustic Sensing(DAS) Near-surface structure First-arrival travel time tomography Body wave Active source

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Quantifying the Temporal and Spatial Spread of COVID-19:Empirical Evidence from Shanghai

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Journal of Systems Science and Information 2024年第3期12卷 309-322页

作者： Haowen BAO Zishu CHENG Yuying SUN Yongmiao hong Shouyang WANG Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Economics and Management and MOE Social Science Laboratory of Digital Economic Forecasts and Policy SimulationUniversity of Chinese Academy of SciencesBeijing 100190China School of Entrepreneurship and Management ShanghaiTech UniversityShanghai 201210China

The worldwide spread of COVID-19 has caused a grave threat to human life, health, and socio-economic development. It is of great significance to study the transmission mechanism of COVID-19 and evaluate the effect of epidemic prevention policies. This paper employs a spatial dynamic panel data(SDPD) model to analyze the temporal and spatial spread of COVID-19, incorporating the time-varying features of epidemic transmission and the impact of geographic *** studies on the COVID-19 outbreak in Shanghai during early 2022 show that the intra-regional transmission of COVID-19 dominated the cross-regional one. Additionally, strict policies are found to effectively reduce the transmission risk of COVID-19 and curb the spillover effect of the epidemic in Shanghai on other regions. Based on these results, we provide three policy suggestions. Furthermore,this research methodology can be extended to investigate other infectious diseases, thereby providing a scientific framework and theoretical basis for evaluating the spread risk of pandemics and formulating appropriate strategies.

关键词： COVID-19 spatial econometrics epidemic prevention policy dynamic

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Combinatorial reasoning-based abnormal sensor recognition method for subsea production control system

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Petroleum Science 2024年第4期21卷 2758-2768页

作者： Rui Zhang Bao-Ping Cai Chao Yang Yu-Ming Zhou Yong-hong Liu Xin-Yang Qi College of Mechanical and Electronic Engineering China University of Petroleum BGP Inc. China National Petroleum Corporation

The subsea production system is a vital equipment for offshore oil and gas production. The control system is one of the most important parts of it. Collecting and processing the signals of subsea sensors is the only way to judge whether the subsea production control system is normal. However, subsea sensors degrade rapidly due to harsh working environments and long service time. This leads to frequent false alarm incidents. A combinatorial reasoning-based abnormal sensor recognition method for subsea production control system is proposed. A combinatorial algorithm is proposed to group sensors. The long short-term memory network(LSTM) is used to establish a single inference model. A counting-based judging method is proposed to identify abnormal sensors. Field data from an offshore platform in the South China Sea is used to demonstrate the effect of the proposed method. The results show that the proposed method can identify the abnormal sensors effectively.

关键词： Abnormal sensor Combinatorial algorithm Fault identification Subsea production control system

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Magnetic field imaging with radio-frequency optically pumped magnetometers [Invited]

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Chinese Optics Letters 2024年第6期22卷 38-45页

作者： Xiyu Liu Junlong Han Wei Xiao Teng Wu Xiang Peng hong Guo School of Electronics Peking UniversityBeijing 100871China

High-sensitivity radio-frequency optically pumped magnetometers (RF-OPMs), working without cryogenic condition, play a critical role in magnetic field imaging(MFI) at low frequencies(e.g., 100 Hz to 1 MHz). We introduce the principle of operation and recent developments of RF-OPMs and focus on reviewing the MFI applications in magnetic induction tomography, ultralow-field magnetic resonance imaging, and magnetic particle imaging. For the applications of RF-OPMs, ranging from industrial monitoring to medical imaging and security screening, the unshielded and portable RF-OPMs(and RF-OPM array)techniques are still under the further development for detecting and scanning over the target object for accomplishing the final three-dimensional imaging, and thus extremely require the abilities of active compensation of the ambient magnetic field and sensor miniaturization in the future.

关键词： magnetic field imaging radio frequency optically pumped magnetometer

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Numerical and experimental study of the effects of wind turbine operation on sand-dust transport characteristics

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 97-113页

作者： Gaosheng Ma hong Han Ye Li Deshun Li Yan Wang Ning Fu Quan Zheng Rennian Li School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China Gansu Provincial Technology Center for Wind Turbines Lanzhou 730050China Key Laboratory of Fluid Machinery and Systems Lanzhou 730050China Multiple Function Towing Tank Laboratory State Key Laboratory of Ocean EngineeringSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Given factors such as reduced land availability for onshore wind farms,wind resource enrichment levels,and costs,there is a growing trend of establishing wind farms in deserts,the Gobi,and other arid ***,the relationship between sanddust weather environments and wind turbine operations has garnered significant *** investigate the impact of wind turbine wakes on sand-dust transportation,this study employs large eddy simulation to model flow fields,coupled with an actuator line model for simulating rotating blades and a multiphase particle in cell model for simulating sand *** research focuses on a horizontal axis wind turbine model and examines the motion and spatiotemporal distribution characteristics of four typical sizes of sand particles in the turbine *** findings reveal that sand particles of varying sizes exhibit a spiral settling pattern after traversing the rotating plane of wind turbine blades,influenced by blade shedding vortex and *** particles tend to cluster in the peripheries of the vortex cores of low vorticity in the wind turbine *** rotation of wind turbines generates a wake vortex structure that causes a significant clustering of sand particles at the tip *** the wake distance increases,the particles that cluster at the turbine's tip gradually spread outward to approximately twice the rotor diameter and then begin to mix with the incoming flow *** turbines have a noticeable impact on sand-dust transportation,hindering their movement to a significant *** average sand-blocking rate exhibits a trend of initially increasing and then decreasing as the wake distance *** its peak,the sand-blocking rate reaches an impressive 67.55%.The presence of wind turbines induces the advanced settling of sand particles,resulting in a“triangular”distribution of the deposition within the ground projection area of the wake.

关键词： wind turbine particle transportation actuator line model dry deposition particle clustering

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Biophotoelectrochemistry for the treatment of emerging contaminants

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Science China Technological Sciences 2024年第10期67卷 3051-3066页

作者： HU Jing CHEN Man GU WenZhi DENG WenEr hong MingQiu HU AnDong YE Jie ZHOU ShunGui Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry University

Emerging contaminants(ECs) of significant concern are widely distributed throughout the environment due to various industrial practices and human activities. Given the alarming ecological threats and potential risks that ECs pose to human health and aquatic life, even at trace concentrations, it is imperative to develop innovative technologies to effectively address these challenges. The biophotoelectrochemistry(BPEC) system, which integrates microbial cells with photosensitizers for solar-tochemical conversion, holds great potential as an efficient strategy for the removal of ECs. In this review, we provide new insights into the BPEC system for the ECs treatment by systematically summarizing the classification, sources, and environmental occurrence of ECs. Additionally, we explore the research progress and degradation mechanisms in ECs removal with ***, the current challenges and future perspectives for the applications of the BPEC system in the ECs treatment are *** review aims to promote the development of BPEC technology for ECs treatment, offering a promising prospect for environmental remediation, circular economy, and clean-energy production.

关键词： emerging contaminants biophotoelectrochemistry photocatalysis biodegradation

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A self-cleaning window for high-efficiency photodegradation of indoor formaldehyde

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Chinese Chemical Letters 2024年第9期35卷 340-345页

作者： Changzhu Huang Wei Dai Shimao Deng Yixin Tian Xiaolin Liu Jia Lin hong Chen Department of Physics Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric PowerShanghai University of Electric PowerShanghai 200090China Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution ControlGuangdong Provincial Key Laboratory of Soil and Groundwater Pollution ControlSchool of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China Eastern Institute for Advanced Study Eastern Institute of TechnologyNingbo 315200China

Formaldehyde(HCHO)as an indoor air pollutant released by new furniture and decorative materials is of great *** a self-cleaning device to remove HCHO is an ideal way to improve indoor air *** this study,a self-cleaning window with a multilayered structure constructed from fluorinedoped tin oxide/bismuth tungstate/resorcinol-formaldehyde resin(FTO/Bi_(2)WO_(6)/RF)has been fabricated,which is capable of degrading HCHO in natural indoor *** as-fabricated device could utilize the natural room light and promote the generation and transfer of the photocatalytic carriers in Bi_(2)WO_(6),which subsequently delivers a good catalytic oxygen reduction efficiency in RF to produce hydrogen peroxide(H_(2)O_(2)).The as-synthesized H_(2)O_(2)could further split into hydroxyl radicals(•OH),then oxide the HCHO molecules in the *** present study demonstrates a novel and efficient strategy to fabricate a transparent multifunctional window for self-cleaning indoor gaseous pollutants,the concept is of great importance to be expanded in a broad range of indoor furniture for in-house air pollution control.

关键词： Bismuth tungstate Resorcinol-formaldehyde Photocatalysis Hydrogen peroxide HCHO degradation

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The First Reported Case of Co-Infection with Neisseria Meningitidis and Bordetella Pertussis in the Cerebrospinal Fluid Specimen of a Normal Four-Year-Old Child

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Biomedical and Environmental Sciences 2024年第4期37卷 432-435页

作者： XIA Xian LI Guo Ming TANG Yi WANG Si Quan HE Fei JIANG Yong Zhong YANG hong Mei JIANG hong Lin LYU Jing MAO Ling Feng Hubei Key Laboratory of Edible Wild Plants Conservation&Utilization Hubei Normal UniversityHuangshi 430070HubeiChina Hubei Provincial Center for Disease Control and Prevention Wuhan 430079HubeiChina Joint Research Center for Molecular Diagnosis of Severe Infection in Children Binjiang Institute of Zhejiang UniversityHangzhou 310058ZhejiangChina

Pertussis is an acute and highly contagious respiratory disease caused by Bordetella pertussis(***),which occurs in people of all ages and is most dangerous for young children,especially *** introduction of whole-cell pertussis vaccines(wPVs)in the 1950s dramatically reduced the incidence of pertussis worldwide[1].However,over the past two decades,many studies have reported the resurgence of pertussis in different countries[2].Epidemiological surveillance in Hubei Province over the last 3 years revealed a clear increasing trend in the incidence of pertussis during the coronavirus disease 2019(COVID-19)epidemic.

关键词： Pertussis dangerous Hubei

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Grain yield and N uptake of maize in response to increased plant density under reduced water and nitrogen supply conditions

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Journal of Integrative Agriculture 2024年第1期23卷 122-140页

作者： Jingui Wei Qiang Chai Wen Yin hong Fan Yao Guo Falong Hu Zhilong Fan QimingWang State Key Laboratory of Aridland Crop Science Lanzhou 730070China College of Agronomy Gansu Agricultural UniversityLanzhou 730070China College of Life Sciences Northwest Normal UniversityLanzhou 730070China

The development of modern agriculture requires the reduction of water and chemical N fertilizer *** the planting density can maintain higher yields,but also consumes more of these restrictive ***,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains *** study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to *** treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N *** water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme *** with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improv

关键词： water and N reduction plant density maize grain yield N uptake compensation effect

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