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ACOUSTOELASTIC THEORY FOR FLUID-SATURATED POROUS MEDIA

Acta Mechanica Solida Sinica 2014年第1期27卷 41-53页

作者： huaqing wang Jiayong Tian Institute of Crustal Dynamics China Earthquake Administration

Based on the finite deformation theory of the continuum and poroelastic theory, the aeoustoelastic theory for fluid-saturated porous media （FSPM） in natural and initial coordi- nates is developed to investigate the influence of effective stresses and fluid pore pressure on wave velocities. Firstly, the assumption of a small dynamic motion superimposed on a largely static pre- deformation of the FSPM yields natural, initial, and final configurations, whose displacements, strains, and stresses of the solid-skeleton and the fluid in an FSPM particle could be described in natural and initial coordinates, respectively. Secondly, the subtraction of initial-state equations of equilibrium from the final-state equations of motion and the introduction of non-linear constitu- rive relations of the FSPM lead to equations of motion for the small dynamic motion. Thirdly, the consideration of homogeneous pre-deformation and the plane harmonic form of the small dynamic motion gives an acoustoelastic equation, which provides analytical formulations for the relation of the fast longitudinal wave, the fast shear wave, the slow shear wave, and the slow longitudinal wave with solid-skeleton stresses and fluid pore-pressure. Lastly, an isotropic FSPM under the close-pore jacketed condition, open-pore jacketed condition, traditional unjacketed condition, and triaxial condition is taken as an example to discuss the velocities of the fast and slow shear waves propagating along the direction of one of the initial principal solid-skeleton strains. The detailed discussion shows that the wave velocities of the FSPM are usually influenced by the effective stresses and the fluid pore pressure. The fluid pore-pressure has little effect on the wave velocities of the FSPM only when the components of the applied initial principal solid-skeleton stresses or strains are equal, which is consistent with the previous experimental results.

关键词： acoustoelasticity fluid-saturated porous media wave velocity the effective stress fluid pore pressure

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A novel sparse feature extraction method based on sparse signal via dual-channel self-adaptive TQWT

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Chinese Journal of Aeronautics 2021年第7期34卷 157-169页

作者： Junlin LI huaqing wang Liuyang SONG College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of High-end Mechanical Equipment Health Monitoring and Self-Recovery Beijing University of Chemical TechnologyBeijing 100029China

Sparse signal is a kind of sparse matrices which can carry fault information and simplify the signal at the same *** can effectively reduce the cost of signal storage,improve the efficiency of data transmission,and ultimately save the cost of equipment fault diagnosis in the aviation *** present,the existing sparse decomposition methods generally extract sparse fault characteristics signals based on orthogonal basis atoms,which limits the adaptability of sparse *** this paper,a self-adaptive atom is extracted by the improved dual-channel tunable Q-factor wavelet transform(TQWT)method to construct a self-adaptive complete ***,the sparse signal is obtained by the orthogonal matching pursuit(OMP)*** atoms obtained by this method are more flexible,and are no longer constrained to an orthogonal basis to reflect the oscillation characteristics of ***,the sparse signal can better extract the fault *** simulation and experimental results show that the selfadaptive dictionary with the atom extracted from the dual-channel TQWT has a stronger decomposition freedom and signal matching ability than orthogonal basis dictionaries,such as discrete cosine transform(DCT),discrete Hartley transform(DHT)and discrete wavelet transform(DWT).In addition,the sparse signal extracted by the self-adaptive complete dictionary can reflect the time-domain characteristics of the vibration signals,and can more accurately extract the bearing fault feature frequency.

关键词： Complete dictionary Data transmission Fault diagnosis Sparse matrices Sparse signal Wavelet transform

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Feature Extraction Method Based on Pseudo-Wigner-Ville Distribution for Rotational Machinery in Variable Operating Conditions

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Chinese Journal of Mechanical Engineering 2011年第4期24卷 661-668页

作者： wang huaqing LIKe SUN Hao CHEN Peng Chemical Safety Engineering Research Center of Ministry of Education Beijing University of Chemical Technology Beijing 100029 China Graduate School ofBioresources Mie University Mie 514-8507 Japan

In the case of fault diagnosis for roller bearings, the conventional diagnosis approaches by using the time interval of energy impacts in time-frequency distribution or the pass-frequencies are based on the assumption that machinery operates under a constant rotational speed. However, when the rotational speed varies in the broader range, the pass-frequencies vary with the change of rotational speed and bearing faults cannot be identified by the interval of impacts. Researches related to automatic diagnosis for rotational machinery in variable operating conditions were quite few. A novel automatic feature extraction method is proposed based on a pseudo-Wigner-Ville distribution （PWVD） and an extraction of symptom parameter （SP）. An extraction method for instantaneous feature spectrum is presented using the relative crossing information （RCI） and sequential inference approach, by which the feature spectrum from time-frequency distribution can be automatically, sequentially extracted. The SPs are considered in the frequency domain using the extracted feature spectrum to identify among the conditions of a machine. A method to obtain the synthetic symptom parameter is also proposed by the least squares mapping （LSM） technique for increasing the diagnosis sensitivity of SP. Practical examples of diagnosis for bearings are given in order to verify the effectiveness of the proposed method. The verification results show that the features of bearing faults, such as the outer-race, inner-race and roller element defects have been effectively extracted, and the proposed method can be used for condition diagnosis of a machine under the variable rotational speed.

关键词： feature extraction pseudo-wigner-ville distribution variable operating condition sequential diagnosis

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Quantitative Diagnosis of Fault Severity Trend of Rolling Element Bearings

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Chinese Journal of Mechanical Engineering 2015年第6期28卷 1254-1260页

作者： CUI Lingli MA Chunqing ZHANG Feibin wang huaqing College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology College of Engineering Jiangxi Agricultural University School of Mechanical and Electrical Engineering Beijing University of Chemical Technology

The condition monitoring and fault diagnosis of rolling element bearings are particularly crucial in rotating mechanical applications in industry. A bearing fault signal contains information not only about fault condition and fault type but also the severity of the fault. This means fault severity quantitative analysis is one of most active and valid ways to realize proper maintenance decision. Aiming at the deficiency of the research in bearing single point pitting fault quantitative diagnosis, a new back-propagation neural network method based on wavelet packet decomposition coefficient entropy is proposed. The three levels of wavelet packet coefficient entropy（WPCE） is introduced as a characteristic input vector to the BPNN. Compared with the wavelet packet decomposition energy ratio input vector, WPCE shows more sensitive in distinguishing from the different fault severity degree of the measured signal. The engineering application results show that the quantitative trend fault diagnosis is realized in the different fault degree of the single point bearing pitting fault. The breakthrough attempt from quantitative to qualitative on the pattern recognition of rolling element bearings fault diagnosis is realized.

关键词： rolling bearing fault quantitative analysis back-propagation neural network wavelet packet coefficient entropy wavelet packet energy ratio

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Why Have cVDPV2 Outbreaks Increased Globally After the Polio Immunization Strategy Switch:Challenges for the Polio Eradication Endgame

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China CDC weekly 2020年第11期2卷 176-179页

作者： huaqing wang Chinese Center for Disease Control and Prevention BeijingChina

Since the World Health Assembly(WHA)set the goal of polio eradication in 1988,the Global Polio Eradication Initiative(GPEI)has reduced the global incidence of polio by more than 99%,and the number of countries with endemic polio decreased from 125 countries to *** for Afghanistan,Pakistan,and Nigeria,wild poliovirus(WPV)transmission has been confirmed to have been interrupted globally.

关键词： Polio dic globally

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SEQUENTIAL DIAGNOSIS FOR A CENTRIFUGAL PUMP BASED ON FUZZY NEURAL NETWORK

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Chinese Journal of Mechanical Engineering 2008年第5期21卷 50-54页

作者： ZHOU Xiong wang huaqing CHEN Peng TANG Yike College of Mechanical Engineering Chongqing University Chongqing 400044 China Engineering Training Center Chongqing University of Science and Technology Chongqing 401331 China College of Mechanical and Electrical Engineering Beijing University of Chemical Technology Beijing 100029 China Graduate School of Bioresources Mie University Tsu 514-8507 Japan

A sequential diagnosis method is proposed based on a fuzzy neural network realized by ＂the partially-linearized neural network （PNN）＂, by which the fault types of rotating machinery can be precisely and effectively distinguished at an early stage on the basis of the possibilities of symptom parameters. The non-dimensional symptom parameters in time domain are defined for reflecting the features of time signals measured for the fault diagnosis of rotating machinery. The synthetic detection index is also proposed to evaluate the sensitivity of non-dimensional symptom parameters for detecting faults. The practical example of condition diagnosis for detecting and distinguishing fault states of a centrifugal pump system, such as cavitation, impeller eccentricity which often occur in a centrifugal pump system, are shown to verify the efficiency of the method proposed in this paper.

关键词： Sequential diagnosis Fuzzy neural network Symptom parameter Centrifugal pump Rotating machinery

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Citric Acid-Enhanced Electroremediation of Toxic Metal-Contaminated Dredged Sediments： Effect of Open/Closed Orifice Condition, Electric Potential and Surfactant

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Pedosphere 2018年第1期28卷 35-43页

作者： Yue SONG Ahmed BENAMAR Salim MEZAZIGH huaqing wang Laboratoire Ondes et Milieux Complexes UMR CNRS 6294 Universite du Havre 76600 Le Havre France Laboratoire Morphodynamique Continentale et Cotiere UMR CNRS 6143 Universite de Caen 14000 Caen France

Citric acid(CA), a widely used eco-friendly electrolyte, can be employed as an agent for enhancing toxic metal(TM) removal from contaminated dredged sediment using electrokinetic(EK) technology. In this study, dredged harbor sediments co-contaminated by TMs were subjected to enhanced EK treatment using a mixture of chelating agent(CA) and surfactant as an additive in the processing fluids. Several control conditions that may influence the efficiency of TM removal were tested, including open/closed sediment chamber orifices, electric potential gradients(0.5, 1.0, and 1.5 V cm^(-1)), and electrolyte surfactant. Tween 20(4 mmol L-1) was used as a surfactant within the electrolyte to investigate the extent of TM removal in sediment with high organic matter content. The results showed that an open orifice led to a greater electro-osmotic flow(EOF) with moderate TM removal. In contrast, a closed orifice with a nonionic surfactant electrolyte allowed the highest removal of TMs from the matrix. Moreover, increasing the electric potential gradient led to a higher EOF under the open orifice condition, but no significant increase in TM removal was observed owing to a higher accumulation of TMs in the middle of the matrix, caused by the opposite direction of EOF and electro-migration of metal-citrate complexes.

关键词： electric potential electrokinetic remediation electro-migration electro-osmotic flow electro-osmotic permeability metal-citrate complex

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Electromagnetic disturbance characteristic of typical high voltage switchgear interruption process in offshore wind farm based on integrated conduction model

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High Voltage 2023年第5期8卷 907-920页

作者： huaqing wang Daochun Huang Mingjing Shuang Huipeng Li Yiqun Qiu Engineering Research Center of Ministry of Education for Lightning Protection and Grounding Technology Wuhan UniversityWuhanChina School of Electrical Engineering and Automation Wuhan UniversityWuhanChina

In an offshore wind farm,a high‐voltage switchgear interruption in an offshore substation creates a high‐frequency,high‐amplitude overvoltage that can cause severe electromagnetic interference problems in the intelligent electronic *** address this issue,mathematical models,vector fitting and finite element method were used to build an integrated electromagnetic disturbance conduction model,whose accuracy was verified by large current interruption *** the simulation of a typical offshore wind farm's single‐phase grounding fault interruption process,the electromagnetic disturbance characteristics and the impact of the ground position are *** results show that during the fault interruption process of phase B grounded,the dominant frequency of disturbance voltage can reach 4.34 MHz,and the amplitude can reach 1.12 *** ground grid has a large impact on the interference voltage,which can reach a maximum value of 2.28 kV under specific *** disturbance voltage in the fault process mainly comes through the current transformer,while during the interruption process,it mainly comes through the ground *** authors provide a method to establish the integrated electromagnetic disturbance simulation model,which can improve the accuracy of the electromagnetic disturbance conduction process simulation of intelligent components.

关键词： offshore fault disturbance

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Update on diffuse large B-cell lymphoma: highlights from the 2022 ASCO Annual Meeting

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Cancer Biology & Medicine 2022年第8期19卷 1117-1120页

作者： Minghan Qiu Shan Wu Xinrui Chen huaqing wang Department of Oncology Tianjin Union Medical CenterNankai UniversityTianjin 300191China The Institute of Translational Medicine Tianjin Union Medical CenterNankai UniversityTianjin 300121China

Diffuse large B-cell lymphoma(DLBCL)is the most common non-Hodgkin’s lymphoma(NHL)and has high *** 30%–50%of patients develop relapsed/refractory(R/R)disease,which remains a major cause of *** recent years,a variety of novel therapies have emerged,including bispecific T-cell engagers(BiTEs),antibody–drug conjugates(ADCs),chimeric antigen receptor T cells(CAR-T),and selective BTK inhibitors,which have provided effective treatment strategies for patients with DLBCL1,***,the 58th Annual Meeting of the American Society of Clinical Oncology(ASCO)was held in Chicago,presenting cutting-edge studies in ***,we discuss a selection of interesting data on this topic.

关键词： lymphoma ASCO mortality

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Trends and Age-Period-Cohort Effect on Acute Hepatitis B Incidence—China,2005-2021

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China CDC weekly 2024年第30期6卷 727-733,I0001,I0002页

作者： Lei wang Na Liu Ning Miao Guomin Zhang Fuzhen wang huaqing wang National Immunization Program Chinese Center for Disease Control and PreventionBeijingChina

Introduction:This study analyzed long-term trends in the incidence of acute hepatitis B(AHB)in China,focusing on age,period,and cohort effects on ***:Data on AHB from 2005 to 2021 were extracted from the National Notifiable Disease Reporting System(NNDRS)of China for *** of AHB were calculated by gender and age group using population denominators from the 2000,2010,and 2020 *** regression was employed to evaluate trends,and an age-period-cohort model was used to assess the age,period,and cohort ***:The annual average incidence of reported AHB in children aged 14 years and below in low,intermediate,and high endemic areas decreased from 1.65,2.33,and 2.56 per 100,000 in 2005-2010 to 0.56,0.58,and 0.48 per 100,000 in the 2016-2021 *** 15-39-year age group in high endemic areas exhibited the most significant decline in incidence,dropping from 23.14 per 100,000 in 2005 to 4.59 per 100,000 in 2021 among males and from 10.62 per 100,000 to 3.21 per 100,000 among ***-period-cohort analysis indicated decreasing age,period,and cohort effects for reported AHB incidence in each endemic area,except for a slight upward trend in the 15-19-year age group and in the cohort born between 1951 and ***:This study demonstrated a rapid decline in AHB incidence across various endemic areas since *** aged 14 years and below exhibited very low AHB incidences,while the incidence among individuals over 15 years was *** further reduce AHB incidence,hepatitis B vaccine(HepB)coverage should be enhanced among adolescents and adults.

关键词： Incidence acute vaccine

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