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Research on denoising of joint detection signal of water quality with multi-parameter based on IEEMD

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Optoelectronics Letters 2024年第2期20卷 107-115页

作者： li wen li Dejian MA Yongyue TIAN Wang wen Xin li Jie Institute of Mechanical and Electrical Engineering North China University of TechnologyBeijing 100144China1

An improved ensemble empirical mode decomposition(IEEMD) is suggested to process water quality spectral signals in order to address the issue that noise interference makes it difficult to extract and evaluate water quality spectral *** algorithm effectively solves the problems of modal mixing,poor reconstruction accuracy in the empirical mode decomposition(EMD),and a large amount of calculation in the ensemble empirical mode decomposition(EEMD).Based on EEMD,IEEMD firstly preprocesses the original water quality spectral signals,then performs Savitzky-Golay(S-G) smoothing on the decomposed effective intrinsic mode function(IMF) components,and finally reconstructs them to obtain the denoised *** sample data at different concentrations can be accurately analyzed based on the noise-reduced spectral *** this paper,three water quality parameters are used as research objects:benzene(C_(6)H_(6)),benzo(b)fluoranthene(C_(20)H_(12)),and chemical oxygen demand(COD).The original water quality multi-parameter(C_(6)H_(6),C_(20)H_(12),COD) spectral signals were subjected to denoising based on the IEEMD and the water quality multi-parameter joint detection *** signal-to-noise ratio(SNR) and the correlation coefficient(R^(2)) of the fitted curves obtained from the processing of the IEEMD were compared and analyzed with those obtained from the processing of the EMD and the *** experimental results show that the SNR of the spectral signals and the R^(2) of the fitting curve in three water quality parameters have been significantly ***,the IEEMD effectively improves the phenomenon of modal mixing,reduces the amount of calculation,improves the reconstruction accuracy,and provides an important guarantee for the effective extraction of multi-parameter spectral signals of water quality.

关键词： signal parameter noise

EXPERIMENT ON THE CHARACTERISTICS OF 3-D VORTEX RING BEHIND A FLEXIBLE OSCILLATING CAUDAL FIN

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Journal of Hydrodynamics 2010年第3期22卷 393-401页

作者： WANG Zhi-dong LAO Yi-jia li li-jun CONG wen-chao School of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China Technology Research Economy Development Institute B eijing 10081 China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China

A test for the wake vortex of a flexible oscillating caudal fin is carried out with Digital Particle Image Velocimetry （DPIV）, and the variation of vortex distance and the vorticity in the range of oscillating frequency from 0.704 Hz to 1.17 Hz are analyzed. It is found that with the increase of the oscillating frequency, the vortex distance decreases and the peak of the vorticity increases, When the Strouhal number is smaller than 0.49, a larger thrust component is obtained. The distribution of the velocity circulation and the vortex distance in the different spanwise section of the caudal fin are given, and then the dimension of the vortex ring is determined. The radius of the vortex ring is 79.3 mm and the average velocity circulation is 28152.9 mm2/s at the oscillating frequency of 0.835 Hz. The model of 3-D vortex ring chain of flexible oscillating caudal fin is constructed based on the information of wake vortex field. Finally, an effective analysis method is provided for establishing the relationship of oscillating parameters for the caudal fin and the wake structure and the intrinsic mechanism of efficient fish swimming is investigated.

关键词： Digital Particle Image Velocimetry (DPIV) flexible caudal fin flow field vortex ring

Outcomes of high-grade aneurysmal subarachnoid hemorrhage patients treated with coiling and ventricular intracranial pressure monitoring

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World Journal of Clinical Cases 2021年第19期9卷 5054-5063页

作者： li-li wen Xiao-Ming Zhou Sheng-Yin Lv Jiang Shao Han-Dong Wang Xin Zhang Department of Neurosurgery Jinling HospitalNanjing University School of MedicineNanjing 210002Jiangsu ProvinceChina Department of Neurology The Second Hospital of NanjingNanjing 210003Jiangsu ProvinceChina

BACKGROUND High-grade aneurysmal subarachnoid hemorrhage is a devastating disease with a low favorable *** intracranial pressure is a substantial feature of high-grade aneurysmal subarachnoid hemorrhage that can result to secondary brain *** control of intracranial pressure including decompressive craniectomy and external ventricular drainage had been reported to be associated with improved *** in recent years,little is known whether external ventricular drainage and intracranial pressure monitoring after coiling could improve outcomes in high-grade aneurysmal subarachnoid *** To investigate the outcomes of high-grade aneurysmal subarachnoid hemorrhage patients with coiling and ventricular intracranial pressure *** A retrospective analysis of a consecutive series of high-grade patients treated between Jan 2016 and Jun 2017 was *** our center,followed by continuous intracranial pressure monitoring,the use of ventricular pressure probe for endovascular coiling and invasive intracranial pressure monitoring in the acute phase is considered to be the first choice for the treatment of high-grade *** retrospectively analyzed patient characteristics,radiological features,intracranial pressure monitoring parameters,complications,mortality and *** A total of 36 patients were included,and 32(88.89%)*** overall mortality rate was 11.11%.No patient suffered from aneurysm *** intracranial pressure in 33 patients(91.67%)was maintained within the normal range by ventricular drainage during the treatment.A favorable outcome was achieved in 18 patients(50%)with 6 mo *** cerebral ischemia and Glasgow coma scale were considered as significant predictors of outcome(2.066 and-0.296,respectively,P<0.05).CONCLUSION Ventricular intracranial pressure monitoring may effectively maintain the intracranial pressure within the normal *** the small number of cases in th

关键词： Subarachnoid hemorrhage High-grade Outcome Ventricular drainage Intracranial pressure

Two Indium(III)-based Fluorescent Metal-Organic Frameworks for Highly Sensing Fe^(3+),2,4-DNP,and TNP

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Chemical Research in Chinese Universities 2024年第1期40卷 119-126页

作者： WANG Dan li wen li Guanghua HUA Jia liU Yunling State Key Laboratory of Inorganic Synthesis&Preparative Chemistry Jilin UniversityChangchun130012P.R.China

Two novel metal-organic frameworks(MOFs),JLU-MOF130([In(NH2−BDC)(Imi)(1H−Imi)]·DMF·H2O,NH2−H2BDC=2-aminobenzene-1,4-dicarboxylic acid,1H−Imi=1H-imidazole,DMF=N,N-dimethylformamide)and JLU-MOF131([In(1,4-NDC)(Imi)(1H−Imi)]·DMF0.5,1,4-H_(2)NDC=1,4-naphthalene-dicarboxylic acid),were ***-MOF130 features a three-dimensional(3D)architecture with a neb ***-MOF131 is characterized by a two-dimensional(2D)structure with an sql ***-MOF130 has excellent fluorescence detection performance towards Fe^(3+),2,4-dinitrophenol(2,4-DNP),and 2,4,6-trinitrophenol(TNP),but the fluorescence detection performance of JLU-MOF131 is further improved by converting NH2−H2BDC to more conjugated 1,4-H_(2)*** Stern-Volmer(SV)quenching constant(KSV)values of JLU-MOF130 sensing 2,4-DNP,TNP,and Fe^(3+)are 5.24×10^(4),4.44×10^(4),and 4.73×10^(3) L/mol,*** corresponding limit of detection(LOD)values are 1.17,1.36,and 14.59µmol/*** KSV values for JLU-MOF131 are 1.26×10^(5),9.02×10^(4),and 8.48×103 L/mol,and the corresponding LOD values are 0.35,0.42,and 3.60µmol/L,***,the emission wavelengths of the two MOFs obviously shift as the fluorescence emission intensities decrease upon the addition of 2,4-DNP and TNP,which can be applied in selective detection.

关键词： Metal-organic framework Fluorescence quenching Fe^(3+) 2 4-Dinitrophenol(2 4-DNP) 2 4 6-Trinitrophenol(TNP)

Hole cleaning evaluation and installation spacing optimization of cuttings bed remover in extended-reach drilling

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Petroleum Science 2024年第3期21卷 2005-2022页

作者： Shuo Peng wen-Jun Huang De-li Gao MOE Key Laboratory of Petroleum Engineering China University of Petroleum-BeijingBeijing102249China State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing102249China

In extended-reach or long-horizontal drilling,cuttings usually deposit at the bottom of the *** cuttings accumulate to a certain thickness,complex problems such as excessive torque and drag,tubing buckling,and pipe stuck probably occur,which results in a lot of non-productive time and remedial *** bed remover can efficiently destroy deposited cuttings in time through hydraulic and mechanical stirring *** paper aims to build a method for hole cleaning evaluation and installation spacing optimization of cuttings bed remover to improve the wellbore cleaning ***,a Computational Fluid Dynamics approach with Eulerian—Eulerian multiphase model was utilized to investigate the mechanism of cuttings transportation,and a new type of cuttings bed remover was ***,an evaluation method of hole cleaning effect of remover was *** that,the effects of several drilling parameters on hole cleaning including flow rate of drilling fluid,rotational speed of drillpipe,rate of penetration,wellbore size,rheological property of drilling fluid,and remover eccentricity on the performance of cuttings bed remover were *** results demonstrate that the new type of remover with streamline blade performs better than conventional *** efficiency of hole cleaning is greatly improved by increasing the rotational speed of drillpipe,flow rate of drilling fluid,remover eccentricity,and 6 rpm Fann dial reading for drilling *** higher rate of penetration and large wellbore size result in worse hole *** findings can serve as an important guide for the structure optimization design of cuttings bed remover and installation spacing of removers.

关键词： Extended-reach drlling Drilling hydraulics Cuttings transport Hole cleaning Cuttings bed remover

Gear walk instability caused by brake-disc friction characteristics

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Chinese Journal of Aeronautics 2024年第2期37卷 343-359页

作者： Xiaoqiong DU Bin li wen CAI linyin LUO School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering University of MichiganAnn Arbor 48109USA AVIC General Huanan Aircraft Industry Co.Ltd. Zhuhai 519040China

A multi-body dynamic rigid-flexible coupling model of landing gear is established to study the gear walk instability caused by the friction characteristics of the brake *** validating the model with the experimental results,the influence of the landing gear structure and braking system parameters on gear walk is further *** the above factors,the slope of the graph for the friction coefficient of the brake disc and the relative velocity of brake stators and rotors is the most influential factor on gear walk *** trajectory analysis verifies that gear walk occurs when the coupling of multiple factors causes the system to exhibit an equivalent negative damping *** consider a more realistic braking case,a back propagation neural network method is employed to describe the nonlinear behavior of the friction coefficient of the brake *** the realistic nonlinear model of the friction coefficient,the maximum error in predicting the braking torque is less than 10%and the effect of the brake disc temperature on gear walk is *** results reveal that a more negative friction slope may contribute to a more severe unstable gear walk,and reducing the braking pressure is an effective approach to avoid gear walk,which provides help for future braking system design.

关键词： Gear walk Friction characteristics of brake disc Brake-induced vibration Negative damping Rigid-flexible coupling Negative slope of braking torque

Distributed user pairing and effective computation offloading in aerial edge networks

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Chinese Journal of Aeronautics 2024年第4期37卷 378-390页

作者： Wei liANG Shuhui wen lixin li Jingjing CUI School of Electronics and Information Northwestern Polytechnical UniversityXi’an CN710072China The State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an CN710126China School of Electronics and Computer Science University of SouthamptonSouthampton SO167NSUK

Future Sixth-Generation (6G) mobile communication networks extremely require the global connectivity and the ground Base Stations (BSs) are difficult to develop in some specific areas,such as mountainous ***,the aerial networks are the key framework for the future communications,in which the aerial vehicle could act as the access ***,Mobile Edge Computing (MEC) is also essential to enhance the data processing capabilities of aerial *** this paper,we study a comprehensive communication-computation resource management problem for jointly optimizing user pairing,power and time allocation in the MEC aided Cognitive Radio (CR) aerial networks,namely CR-MEC aerial ***,this multilevel optimization problem could be decomposed into the user pairing and power allocation as well as time allocation *** the conceived CR-MEC aerial networks,we propose a User Pairing and Computation Offloading Management Algorithm (UPCOMA) based on three-sided matching theory,aiming to minimize the system’s energy *** the first step of UPCOMA,multiple Primary Users (PUs) and Cognitive Users (CUs) on the ground negotiate to each other with the suitable power allocation coefficients and construct the stable user ***,the stable user pairs would match to a high altitude platform who act as the base station,which is for appropriately allocating Transmission Time Slots (TSs) at the second step of ***,a hybrid offloading mode is proposed in our conceived networks in order to support ground users to offload their tasks adaptively according to their individual ***,the simulation results reveal that the relative performance of UPCOMA is close to that of the Brute-Force Search Algorithm (BFSA) with low ***,the hybrid offloading mode with less energy consumption supports much more ground user pairs to offload tasks compared to the binary mode.

关键词： Aerial edge computing Binary offloading Cognitive radio Hybrid offloading Resource management

Embedded Majorana islands

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 154-164页

作者： Jin-Xing Hou Alex Weststrom Rui Wang wen-li Yang Jian li Institute of Modern Physics Northwest UniversityXi’an 710127China Department of Physics School of ScienceWestlake UniversityHangzhou 310030China Shaanxi Key Laboratory for Theoretical Physics Frontiers Xi’an 710127China Institute of Natural Sciences Westlake Institute for Advanced StudyHangzhou 310024China National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center for Advanced Microstructures Nanjing 210093China Peng Huanwu Center for Fundamental Theory Xi’an 710127China

Mesoscopic superconducting islands hosting Majorana zero modes(MZMs),or Majorana islands in short,offer a prototype of topological *** this work we investigate theoretically the model of a generic Majorana island tunneling-coupled to a singlepiece metallic substrate,hence an embedded Majorana *** show the crucial consequences of an interplay between the topological ground states nonlocally addressed by the MZMs and the metallic bath with coherent electron propagation:on the one hand,the topological degeneracy on the Majorana island can be preserved,by virtue of the particle-hole symmetry,despite the apparent bath-induced coupling between MZMs;on the other hand,the electronic interference in the metallic bath may lead to profound alterations to the renormalization group behavior of the hybrid system towards low energy/temperature compared with conventional Kondo *** work serves to establish the model of embedded Majorana islands as an experimentally relevant and theoretically intriguing problem particularly in the direction of topological quantum computation.

关键词： topological quantum computation Majorana zero modes topological qubit mesoscopic superconductor topological Kondo effect

The adsorption effect of aquaculture residual feed on heavy metals and its impact on microbial metabolism of feed

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Ecological Processes 2024年第2期13卷 246-259页

作者： Sufeng Wang Zijng Wang wen Zhang Jingshan li Mingyang lin li Chen State Key Laboratory of Metastable Materials Science and Technology Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse Yanshan University Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province College of Biology and Environmental EngineeringZhejiang Shuren University Hebei Ocean & Fisheries Science Research Institute

Background Intensive and large-scale aquaculture has a high biological density, and a large amount of artificial feed must be provided. As a result, residual feed would be discharged into natural water bodies with water exchange. Due to heavy metal pollution in surface water, residual feed may adsorb heavy metals in the water, affecting the subsequent microbial degradation of feed and the restoration of the water environment. The combined ecological impacts of these two types of pollution urgently need to be *** This study explored the adsorption effect of residual feed on heavy metals and its impact on microbial degradation of residual feed. The results showed that both the insoluble component（mainly fiber, ash, and ether extract, abbreviated as FAE） and soluble component（soluble protein and starch） of the feed had adsorption effects on heavy metals. As the salinity increased, the adsorption capacity of Cu2+and Cd2+decreased, while the adsorption effect on Pb2+was not changed significantly. The adsorption of heavy metals by residual feed could affect the biological degradation of residual feed. The residual feed could adsorb heavy metals and bacterial cells simultaneously, forming FAE-B（bacteria）-S（starch）-Pr（protein）-metal adsorption complex. This adsorption effect could reduce the negative impact of heavy metals on microbial degradation of residual feed. The simulated degradation experiments in actual water bodies also confirmed this. However, the accumulation of heavy metals in residual feed may bring negative effects, such as being consumed by aquatic organisms and entering the food *** The results of this study provide a basis for the collection and centralized treatment of residual feed in aquaculture, as well as the control and remediation of residual feed pollution in natural water bodies.

关键词： Residual feed Adsorption complex Feed pollution Heavy metal