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EVALUATION OF THE SHADING METHOD FOR REDUCING IMAGE BLOOMING IN THE PIV MEASUREMENT OF OPEN CHANNEL FLOWS

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Journal of Hydrodynamics 2012年第2期24卷 184-192页

作者： ZHONG Qiang li dan-xun CHEN Qi-gang WANG Xing-kui State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China

The shading method is a simple but effective way of reducing image blooming in the measurement of open channel flows with the Particle Image Velocimetry （PIV）.The current paper proposes a simplified analytical model for light attenuation using this *** model is verified against experimental data,and the influence of several parameters is illustrated *** possible adverse effect due to the light attenuation is shown to be limited when the parameters in the shading method are in an adequate range,as shown by processing standard images of Case B in PIV Challenge 03.A simple criterion for setting the shade in experiment is given for controlling the errors caused by the shading technique within an acceptable range.

关键词： Particle Image Velocimetry (PIV) blooming shade open channel flows

SOME NEW DATA AND FORMULAS FOR RESISTANCE FLOW IN FLUVIAL OPEN CHANNELS

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Journal of Hydrodynamics 2011年第4期23卷 527-534页

作者： YANG Sheng-fa HU Jiang li dan-xun WANG Xing-kui GUO Yakun Department of River and Ocean Chongqing Jiaotong University Chongqing 400074 China State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China School of Engineering University of Aberdeen Aberdeen AB24 3UE UK

Flow resistance in fluvial open channels, especially in steep gravel-bed channels, still presents challenges to researchers and engineers. This article presents some new data from both the flume experiments and field measurements. Data analysis using the divided hydraulic radius approach shows that the relative roughness plays a significant role in the bed form resistance. A new set of formulas that incorporate the relative roughness are proposed. As compared with several existing formulas, the proposed formulas can be used to better estimate the bed form resistance.

关键词： open channel flow flow resistance relative roughness steep gravel-bed flume experiments field measurements

Cooperative guidance law with maneuverability awareness:A decentralized solution

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Chinese Journal of Aeronautics 2024年第7期37卷 450-457页

作者： Shuyang XU xun SONG Chaoyong li College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Beijing Institute of Electronic System Engineering Beijing 100074China

In this paper,we propose a cooperative guidance law aimed to achieve coordinated impact angles with limited observation on target *** primary challenge lies in establishing an appropriate communication graph among all missiles and devising an algorithm to estimate target acceleration information during *** address this,we propose a specific communication topology and employ a numerical integration-based estimation ***,a distributed algorithm is introduced to facilitate consensus on target acceleration *** upon these foundations,we design an optimal-control-based distributed guidance law for each *** of the proposed guidance law is validated through numerical simulations.

关键词： Cooperative guidance Target maneuver estimation Distributed estimation Consensus Optimal control

A novel evasion guidance for hypersonic morphing vehicle via intelligent maneuver strategy

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Chinese Journal of Aeronautics 2024年第5期37卷 441-461页

作者： xun li Xiaogang WANG Hongyu ZHOU Yu li Department of Aerodynamics Harbin Institute of TechnologyHarbin 150001China Beijing Aerospace Technology Institute Beijing 100074China

This paper presents a novel evasion guidance law for hypersonic morphing vehicles,focusing on determining the optimized wing's unfolded angle to promote maneuverability based on an intelligent ***,the pursuit-evasion problem is modeled as a Markov decision *** the agent's action consists of maneuver overload and the unfolded angle of wings,which is different from the conventional evasion guidance designed for fixed-shape *** reward function is formulated to ensure that the miss distances satisfy the prescribed bounds while minimizing energy ***,to maximize the expected cumulative reward,a residual learning method is proposed based on proximal policy optimization,which integrates the optimal evasion for linear cases as the baseline and trains to optimize the performance for nonlinear engagement with multiple ***,offline training guarantees improvement of the constructed evasion guidance law over conventional ***,the guidance law for online implementation includes only analytical *** maps from the confrontation state to the expected angle of attack and the unfolded angle while retaining high computational *** show that the proposed evasion guidance law can utilize the change of unfolded angle to extend the maximum overload *** it surpasses conventional maneuver strategies by ensuring better evasion efficacy and higher energy efficiency.

关键词： Hypersonic vehicles Variable-sweep wings Evasion guidance Reinforcement learning Pursuit-evasion problem

Perspective on new cell-free DNA technologies for early cancer detection

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Cancer Biology & Medicine 2024年第2期21卷 139-143页

作者： Jie li xun Lan Department of Basic Medical Sciences School of MedicineTsinghua UniversityBeijing 100084China MOE Key Laboratory of Bioinformatics Tsinghua UniversityBeijing 100084China Tsinghua-Peking Joint Center for life Sciences Tsinghua UniversityBeijing 100084China

High cancer heterogeneity and aggressiveness are major factors contributing to the poor prognosis of patients with advanced cancer~(1-5).Early detection of cancer can significantly improve the prognosis of patients with early-stage cancer after standard *** traditional cancer detection technologies,such as endoscopy for gastrointestinal cancer,mammography for breast cancer。

关键词： prognosis cancer patients

In Situ-Constructed lixMoS2 with Highly Exposed Interface Boosting High-Loading and Long-life Cathode for All-Solid-State li-S Batteries

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Energy & Environmental Materials 2024年第4期7卷 163-174页

作者： Hao li Rui Wang Jiangping Song dan liu Hongyang Gao Yimin Chao Haolin Tang A State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Department of Chemistry Chemical Engineering and Life Science Wuhan University of Technology Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory School of Chemistry University of East Anglia

As the persistent concerns regarding sluggish reaction kinetics and insufficient conductivities of sulfur cathodes in all-solid-state li-S batteries(ASSLSBs),numerous carbon additives and solid-state electrolytes (SSEs) have been incorporated into the cathode to facilitate ion/electron pathways around ***,this has resulted in a reduced capacity and decomposition of SSEs.

关键词： all-solid-state lithium–sulfur batteries conversion/intercalation high-loading and long-life low carbon content mixed ionic/electronic conductivities

Predictive model for non-malignant portal vein thrombosis associated with cirrhosis based on inflammatory biomarkers

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1213-1226页

作者： Guo-Le Nie Jun Yan Ying li Hong-Long Zhang dan-Na Xie Xing-Wang Zhu xun li The First School of Clinical Medicine Lanzhou UniversityLanzhou 730000Gansu ProvinceChina Department of General Surgery The First Hospital of Lanzhou UniversityLanzhou 730000Gansu ProvinceChina

BACKGROUND Portal vein thrombosis(PVT),a complication of liver cirrhosis,is a major public health *** prediction is the most effective method for PVT diagnosis and *** To develop and validate a nomogram and network calculator based on clinical indicators to predict PVT in patients with *** Patients with cirrhosis hospitalized between January 2016 and December 2021 at the First Hospital of Lanzhou University were screened and 643 patients with cirrhosis who met the eligibility criteria were *** a 1:1 propensity score matching 572 patients with cirrhosis were screened,and relevant clinical data were *** risk factors were identified using the least absolute shrinkage and selection operator(LASSO)and multivariate logistic regression *** inflation factors and correlation matrix plots were used to analyze multicollinearity among the variables.A nomogram was constructed to predict the probability of PVT based on independent risk factors for PVT,and its predictive performance was verified using a receiver operating characteristic curve(ROC),calibration curves,and decision curve analysis(DCA).Finally,a network calculator was constructed based on the *** This study enrolled 286 cirrhosis patients with PVT and 286 without *** analysis revealed 13 variables as strongly associated with PVT *** logistic regression analysis revealed nine indicators as independent PVT risk factors,including etiology,ascites,gastroesophageal varices,platelet count,D-dimer,portal vein diameter,portal vein velocity,aspartate transaminase to neutrophil ratio index,and platelet-to-lymphocyte *** and correlation matrix plot results revealed no significant multicollinearity or correlation among the variables.A nomogram was constructed based on the screened independent risk *** nomogram had excellent predictive performance,with an area under the ROC curve of 0.821 and 0.829 in the

关键词： Portal vein thrombosis liver cirrhosis Nomogram Inflammatory markers Aspartate aminotransferase to neutrophil ratio index Platelet-to-lymphocyte ratio

Effects of Number of Bleed Holes on Shock-Wave/Boundary-Layer Interactions in a Transonic Compressor Stator

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Journal of Thermal Science 2024年第2期33卷 611-624页

作者： li Bai ZHOU xun LUO Lei DU Wei School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous *** bleed holes are arranged on the suction surface in a single row,two staggered rows and three staggered *** each bleed scheme,five bleed pressure ratios are examined at an inlet Mach number of *** results indicate that the aerodynamic performance of the cascade is significantly improved by the porous *** the single-row scheme,the maximum reduction in total pressure losses is 57%.For the two-staggered-row and three-staggered-row schemes,there is an optimal bleed pressure ratio of 1.0,and the maximum reductions in total pressure loss are 68% and 75%,*** low loss in the cascade is due to the well-controlled boundary *** new local supersonic region created by the bleed hole is the key reason for the improved boundary *** vortex induced by side bleeding provides another mechanism for delaying flow *** the bleed holes could create multiple local supersonic regions,which reduce the range of the adverse pressure gradient that the boundary layer needs to *** is the reason why cascades with more bleed holes perform better.

关键词： transonic compressor stator shock wave/boundary layer interaction porous bleed number of bleed holes

F-doped orthorhombic Nb_(2)O_(5) exposed with 97% (100) facet for fast reversible liþ-Intercalation

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Green Energy & Environment 2024年第4期9卷 723-731页

作者： Xiaodi liu Yufeng Tang dan Zhang Guangyin liu Xinwei Luo Yi Shang Xiu li Jianmin Ma College of Chemistry and Pharmaceutical Engineering Nanyang Normal UniversityNanyang473061China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu611731China

Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for li-ion ***,F-doped T-Nb_(2)O_(5) microﬂowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic ***,F-Nb_(2)O_(5) are assembled by single-crystal nanoﬂakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the li^(+)-intercalation ***,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical *** synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).

关键词： Exposed facets Orthorhombic Nb_(2)O_(5) F-doping Pseudocapacitive intercalation anode li-ion storage