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Using time series analysis to assess tidal effect on coastal groundwater level in Southern laizhou Bay, China

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Journal of Groundwater Science and Engineering 2022年第3期10卷 292-301页

作者： She-ming Chen Hong-wei liu fu-tian liu Jin-jie Miao Xu Guo Zhou Zhang Wan-jun Jiang Tianjin Center of China Geological Survey Ministry of Natural ResourcesTianjin 300170China

Sea water intrusion is an environmental problem cause by the irrational exploitation of coastal groundwater resources and has attracted the attention of many coastal *** this study,we used time series monitoring data of groundwater levels and tidal waves to analyze the influence of tide flow on groundwater dynamics in the southern laizhou *** auto-correlation and cross-correlation coefficients between groundwater level and tidal wave level were calculated specifically to measure the boundary conditions along the *** addition,spectrum analysis was employed to assess the periodicity and hysteresis of various tide and groundwater level *** results of time series analysis show that groundwater level fluctuation is noticeably influenced by tides,but the influence is limited to a certain distance and cannot reach the saltwater-freshwater interface in the southern laizhou *** are three main periodic components of groundwater level in tidal effect range(i.e.23.804 h,12.500 h and 12.046 h),the pattern of which is the same as the *** affected groundwater level fluctuations lag behind the *** dynamic analysis of groundwater indicates that the coastal aquifer has a hydraulic connection with seawater but not in a direct *** to the existence of the groundwater mound between the salty groundwater(brine)and fresh groundwater,the maximum influencing distance of the tide on the groundwater is 8.85 *** that the fresh-saline groundwater interface is about 30 km away from the coastline,modern seawater has a limited contribution to sea-salt water intrusion in laizhou *** results of this study are expected to provide a reference for the study on sea water intrusion.

关键词： Groundwater Time series analysis Correlation Spectral analysis Sea-salt water intrusion

Subspace Clustering via Block-Diagonal Decomposition

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Chinese Journal of Electronics 2024年第6期33卷 1373-1382页

作者： Zhiqiang fu Yao ZHAO Dongxia CHANG Yiming WANG Institute of Information Science Beijing Jiaotong University Beijing Key Laboratory of Advanced Information Science and Network Technology China Construction Bank

The subspace clustering has been addressed by learning the block-diagonal self-expressive matrix. This block-diagonal structure heavily affects the accuracy of clustering but is rather challenging to obtain. A novel and effective subspace clustering model, i.e., subspace clustering via block-diagonal decomposition(SCBD), is proposed,which can simultaneously capture the block-diagonal structure and gain the clustering result. In our model, a strict block-diagonal decomposition is introduced to directly pursue the k block-diagonal structure corresponding to k clusters. In this novel decomposition, the self-expressive matrix is decomposed into the block indicator matrix to demonstrate the cluster each sample belongs to. Based on the strict block-diagonal decomposition, the block-diagonal shift is proposed to capture the local intra-cluster structure, which shifts the samples in the same cluster to get smaller distances and results in more discriminative features for clustering. Extensive experimental results on synthetic and real databases demonstrate the superiority of SCBD over other state-of-the-art methods.

关键词： Accuracy Databases Data models Matrix decomposition

Decoupled deep hough voting for point cloud registration

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Frontiers of Computer Science 2024年第2期18卷 147-155页

作者： Mingzhi YUAN Kexue fu Zhihao LI Manning WANG Digital Medical Research Center School of Basic Medical SciencesFudan UniversityShanghai 200032China Shanghai Key Laboratory of Medical Image Computing and Computer Assisted Intervention Shanghai 200032China

Estimating rigid transformation using noisy correspondences is critical to feature-based point cloud ***,a series of studies have attempted to combine traditional robust model fitting with deep *** them,DHVR proposed a hough voting-based method,achieving new state-of-the-art ***,we find voting on rotation and translation simultaneously hinders achieving better ***,we proposed a new hough voting-based method,which decouples rotation and translation ***,we first utilize hough voting and a neural network to estimate *** based on good initialization on rotation,we can easily obtain accurate rigid *** experiments on 3DMatch and 3DLoMatch datasets show that our method achieves comparable performances over the state-of-the-art *** further demonstrate the generalization of our method by experimenting on KITTI dataset.

关键词： point cloud registration robust model fitting deep learning hough voting

Analysis of the dominant frequency in a subsonic compressor stator at near stall condition

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Chinese Science Bulletin 2014年第1期59卷 23-28页

作者： Ke Shi Song fu School of Aerospace Tsinghua University

IDDES method was applied to investigate the highly unsteady flow in a subsonic compressor stator with very large hub clearance and high incidence *** blade loading variation frequency was found close to the rotating instability(RI)frequency f RI&333 Hz observed in the *** analysis of the flow physics shows that the loading variation is caused by the periodic swing of the large scale separated flow on the blade suction side *** breakdown of the leakage vortex has no significant dominant frequencies,thus cannot be the cause of RI in this compressor stator as normally ***,the vortex shedding and vortex breakdown due to shear layer instability at the outer edge of the blade suction surface separation region excite high frequency unsteadiness that can form the sources of noise.

关键词：压气机亚音速静子非定常流动频分状态失速优势频率

Recycling Strategy and Recyclability Assessment Model Based on the Artificial Neural Network

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厦门大学学报（自然科学版） 2002年第S1期41卷 153-154页

作者： liu Zhi-feng, liu Xue-Ping, WANG Shu-wang, liu Guang-fu (College of Mechanical & Auto Engineering, Hefei University of Techno logy, Hefei 230009, China)

Now, a rapidly growing concern for the environmental protection and resource utilization has stimulated many new activities in the in dustrialized world for coping with urgent environmental problems created by the steadily increasing consumption of industrial products. Increasingly stringent r egulations and widely expressed public concern for the environment highlight the importance of disposing solid waste generated from industrial and consumable pr oducts. How to efficiently recycle and tackle this problem has been a very impo rtant issue over the world. Designing products for recyclability is driven by environmental and economic goals. To obtain good recyclability, two measures can be adopted. One is better recycling strategy and technology; the other is design for recycling (DFR). The recycling strategies of products generally inclu de: reuse, service, remanufacturing, recycling of production scraps during the p roduct usage, recycle (separation first) and disposal. Recyclability assessment is a very important content in DFR. This paper first discusses the content of D FR and strategies and types related to products recyclability, and points out th at easy or difficult recyclability depends on the design phase. Then method and procedure of recyclability assessment based on ANN is explored in detail. The pr ocess consists of selection of the ANN input and output parameters, control of t he sample quality and construction and training of the neural network. At la st, the case study shows this method is simple and operative.

关键词： recycling strategy product recycling artificial neural network assessment model design for recycling

Recent progress of residual stress measurement methods: A review

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Chinese Journal of Aeronautics 2021年第2期34卷 54-78页

作者： Jiang GUO Haiyang fu Bo PAN Renke KANG Key Laboratory for Precision and Non-traditional Machining of Ministry of Education Dalian University of TechnologyDalian 116024China

Residual stress is one of the main factors affecting the mechanical properties of materials, such as their strength, plasticity and surface integrity. For instance, tensile stress conditions can adversely affect material performance or component life, while compressive stress conditions can improve material fatigue strength. During the processing of integrated aviation structures, machining deformation caused by residual stress has become one of the most prominent manufacturing problems. Therefore, it is very important to measure and evaluate the stress for real *** paper reviews the research of residual stress measurement methods over the past five years by classifying them according to the measurement methods appearing in each stage. The existing problems and difficulties of each measurement technology are summarized, and future trends are forecasted. This paper provides a reference for further in-depth study of residual stress measurement technologies.

关键词： Destructive testing future trends Measurement Nondestructive testing Residual stress

Modification and Anticorrosion Property of Carbon Steel with TiO_2 Film

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Journal of Iron and Steel Research International 2005年第6期12卷 37-41页

作者： SONG lai-zhou ZHAO Jing WANG Xiu-li Yanshan University Qinhuangdao 066004 China

A new TiO2 modified film on carbon steel was prepared by electroless plating and sol gel composite process. An artificial neural net was used to optimize the preparing condition of the film. The optimized condition of the TiO2-modified film on carbon steel is as follows： plating time of NiP is 50 min, number of dip coating is 4, heat treatment time is 2 h, and the molar ratio of complexing reagent to Ti（OC4 H9）4 is 1.5 ： 1. Corrosion behavior of carbon steel with coating was investigated by polarization resistance measurement, anode polarization, EIS and ESEM measurement. XPS was used to characterize the element valence of the modified film. Results show that carbon steel with TiO2 modified film has good corrosion resistance in 0.5 mol/L of H2SO4 solution and 0.5 mol/L of NaCl solution. It is also found that the preparing condition of forming TiO2-modified film can be obtained easily by the artificial neural net.

关键词： electroless plating sol-gel composite process artificial neural net TiO2-modified film corrosion resistance

A Four-Equation Eddy-Viscosity Approach for Modeling Bypass Transition

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Advances in Applied Mathematics and Mechanics 2014年第4期6卷 523-538页

作者： Guoliang Xu Song fu China Aerodynamics Research and Development Center Mianyang 621000China School of Aerospace Tsinghua UniversityBeijing 100084China

It is very important to predict the bypass transition in the simulation of flows through *** paper presents a four-equation eddy-viscosity turbulence transition model for prediction of bypass *** is based on the SST turbulence model and the laminar kinetic energy concept.A transport equation for the non-turbulent viscosity is proposed to predict the development of the laminar kinetic energy in the pre-transitional boundary layer flow which has been observed in *** turbulence breakdown process is then captured with an intermittency transport equation in the transitional *** performance of this new transition model is validated through the experimental cases of T3AM,T3A and *** in this paper show that the new transition model can reach good agreement in predicting bypass transition,and is compatible with modern CFD software by using local variables.

关键词： Bypass transition non-turbulent viscosity free stream turbulence turbulence model

Simulation of monolithic active pixel sensor with high resistivity epitaxial layer

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Nuclear Science and Techniques 2011年第5期22卷 265-271页

作者： fu Min TANG Zhenan School of Electronic Science and Technology Dalian University of Technology Dalian 116024 China

The time and efficiency of charge collection are the key factors of monolithic active pixel sensor devices for minimum ionizing particles tracking *** this paper,3D models of pixels with different resistivity epitaxial layers(epi-layers) are built and simulated using *** basic characteristics of detectors are evaluated,including electric potential,electric field,and depleted *** indicate that the high resistivity (HR) epi-layer is a better ***,simulation results show that the key collection performance is significantly improved owing to a wider and stronger electric field in the N type HR epi-layer.

关键词：有源像素传感器高电阻率外延层单片模拟 Synopsys公司电荷收集效率跟踪检测