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Automatic and Rapid Throughflow-Based Optimal Design Method for Multi-Stage Axial-Flow Compressors

Journal of Thermal Science 2025年第1期34卷 77-91页

作者： LEI Fan ZHANG Xiawen JU Yaping ZHANG Chuhua department of Fluid Machinery and Engineering School of Energy and Power EngineeringXi'an Jiaotong University Production and environmental department China Huaneng Group.Co.Ltd. State Key Laboratory for Strength and Vibration of mechanical Structures Xi'an Jiaotong University

Throughflow design has the advantages of less time consumption and large optimization space,and thus is the corner stone of advanced design system of multi-stage axial-flow *** majority of relevant studies were limited to the throughflow inverse designs,and quite few works have been till now devoted to the throughflow optimal *** this work,an automatic and rapid throughflow-based optimal design method is proposed for axial-flow compressors in which a throughflow inverse design solver is embedded in optimal genetic algorithm to improve the design efficiency of axial-flow *** types of design parameters in the throughflow inverse design of axial-flow compressors,i.e.,swirl and shroud curve,are simultaneously used to optimize both the blade shape and flow *** proposed method is validated by the redesign optimization of the benchmark axial-flow compressor NASA Stage 35,and the CFD predictions show that the throughflow-based optimization leads to 1.18% efficiency benefit at design *** proposed method is then utilized to the two-dimensional throughflow optimal design of a large-scale 6.5-stage axial-flow industrial *** optimal design results are confirmed by CFD predictions,indicating that the proposed method can effectively improve the design adiabatic efficiency of the compressors by 1.09% within a few minutes on desk-top *** throughflow design implications are also obtained for advanced axial-flow industrial *** work could enhance the capability of throughflow design method and has engineering application value to explore the throughflow optimization space of multi-stage axial-flow compressors.

关键词： NASA

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Effect of a Carbon Fibre-steel Fibre-graphite Conductive Filler on the Electrothermal Properties of Cementitious Materials

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 141-151页

作者： FAN Yanan WEI Hong ZHENG Hongyong DU Hongxiu department of Architecture and environmental Engineering Taiyuan UniversityTaiyuan 030032China College of Civil Engineering Taiyuan University of TechnologyTaiyuan 030032China

Carbon fibre,steel fibre and graphite were used as conductive fillers to prepare cementitious materials with excellent electrothermal *** electrically conductive cementitious materials with different volume dosages were analysed through compressive and flexural strength,electrochemical impedance spectroscopy and temperature rise *** equivalent circuit model was established to study the electrically conductive heat generation mechanism in the electrically conductive cementitious *** results indicate that the mechanical properties of cementitious composite materials with a ternary conductive phase are better than those of pristine cementitious materials because the fibrous filler improves their mechanical ***,the incorporation of graphite in the material reduces its *** fibrous and point-like conductive phase materials into the cementitious material enhances the overall conductive pathway and considerably reduces the electrical resistance of the cementitious material,enhancing its conductive *** volume ratios of carbon fibre,steel fibre and graphite that achieve an optimal complex doping in the cementitious material were 0.35%,0.6%and 6%,*** was determined using the mutation point of each circuit element parameter as the percolation *** addition,at a certain safety voltage,there is a uniform change between the internal and surface temperatures of the conductive cementitious material,and the heating effect in this materialis is considerably better than that in the pristine cementitious material.

关键词： cementitious composites conductive fillers electrothermal properties electrochemical impedance spectroscopy

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Enhancing Deepfake Detection:Proactive Forensics Techniques Using Digital Watermarking

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Computers, Materials & Continua 2025年第1期82卷 73-102页

作者： Zhimao Lai Saad Arif Cong Feng Guangjun Liao Chuntao Wang School of Automation Guangdong University and TechnologyGuangzhou510006China School of Immigration Administration(Guangzhou) China People’s Police UniversityGuangzhou510663China department of mechanical Engineering College of EngineeringKing Faisal UniversityAl Ahsa31982Saudi Arabia Cyber Police Division Guangzhou Public Security BureauGuangzhou510030China School of Forensic Science and Technology Guangdong Police CollegeGuangzhou510320China College of Mathematics and informatics South China Agricultural UniversityGuangzhou510642China

With the rapid advancement of visual generative models such as Generative Adversarial Networks(GANs)and stable Diffusion,the creation of highly realistic Deepfake through automated forgery has significantly *** paper examines the advancements inDeepfake detection and defense technologies,emphasizing the shift from passive detection methods to proactive digital watermarking *** detection methods,which involve extracting features from images or videos to identify forgeries,encounter challenges such as poor performance against unknown manipulation techniques and susceptibility to counter-forensic *** contrast,proactive digital watermarking techniques embed specificmarkers into images or videos,facilitating real-time detection and traceability,thereby providing a preemptive defense againstDeepfake *** offer a comprehensive analysis of digitalwatermarking-based forensic techniques,discussing their advantages over passivemethods and highlighting four key benefits:real-time detection,embedded defense,resistance to tampering,and provision of legal ***,the paper identifies gaps in the literature concerning proactive forensic techniques and suggests future research directions,including cross-domain watermarking and adaptive watermarking *** systematically classifying and comparing existing techniques,this review aims to contribute valuable insights for the development of more effective proactive defense strategies in Deepfake forensics.

关键词： Deepfake proactive forensics digital watermarking traceability detection techniques

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Mercury contamination and accumulation in sediments of the East China Sea

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Journal of environmental Sciences 2010年第8期22卷 1164-1170页

作者： Tien-Hsi Fang department of Marine environmental informatics "National" Taiwan Ocean University

Mercury （Hg） concentrations in sediment samples collected from the inner and middle shelves of the East China Sea （ECS） were analyzed to evaluate Hg contamination levels and to calculate Hg sedimentation rates and total accumulation in the ECS. The range of Hg concentrations in surface sediments of the inner shelf was 26.5–47.6 ng/g, and that for the middle shelf was 4.1–13.9 ng/g. Hg concentrations correlated well with organic carbon contents but varied inversely with sediment grain size. Enrichment factors indicated that the whole inner shelf and a small portion of the middle shelf were slightly contaminated by Hg. Hg accumulation rates in the ECS ranged between 0.42–48.7 ng/（cm2·yr）, with higher values observed in the inner shelf. Total Hg accumulation in the calculated area （accounting for 80% of the ECS continental shelf area） ranged from 25 to 30 tons/yr; approximately 51% and 17% of the accumulated Hg mass was deposited in the Yangtze estuarine zone and the inner shelf, respectively.

关键词： Hg contamination enrichment factor accumulation the East China Sea

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Enhancing Solar Photovoltaic Efficiency:A Computational Fluid Dynamics Analysis

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Energy Engineering 2025年第1期122卷 153-166页

作者： Rahool Rai Fareed HussainMangi Kashif Ahmed Sudhakar Kumaramsay Faculty of mechanical and Automotive Engineering Universiti Malaysia Pahang Al-Sultan AbdullahPekan26600PahangMalaysia Faculty of Engineering Science&Technology Hamdard UniversityKarachi74600Pakistan Electrical Engineering department SUKKUR IBA UniversitySukkur65200Pakistan Berlin School of Business and Innovation BSBI Faculty of Computer Science and InformaticsBerlin12043Germany Automotive Engineering Centre University Malaysia Pahang Al Sultan AbdullahPekan26600PahangMalaysia Centre for Research in Advanced Fluid&Processes(Fluid Centre) Universiti Malaysia Pahang Al-Sultan Abdullah(UMPSA)Paya BesarKuantan26300PahangMalaysia

The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable *** energy,among the various renewable sources,is particularly appealing due to its abundant ***,the efficiency of commercial solar photovoltaic(PV)modules is hindered by several factors,notably their conversion efficiency,which averages around 19%.This efficiency can further decline to 10%–16%due to temperature increases during peak sunlight *** study investigates the cooling of PV modules by applying water to their front surface through Computational fluid dynamics(CFD).The study aimed to determine the optimal conditions for cooling the PV module by analyzing the interplay between water film thickness,Reynolds number,and their effects on temperature reduction and heat *** CFD analysis revealed that the most effective cooling condition occurred with a 5 mm thick water film and a Reynolds number of *** specific parameters were found to maximize the heat transfer and temperature reduction *** finding is crucial for the development of practical and efficient cooling systems for PV modules,potentially leading to improved performance and longevity of solar *** cooling fluids or advanced cooling techniques that might offer even better efficiency or practical benefits.

关键词： PV module efficiency water film thickness reynolds number CFD analysis PV/T renewable energy

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A novel type of transverse surface wave propagating in a layered structure consisting of a piezoelectric layer attached to an elastic half-space

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Acta Mechanica Sinica 2010年第3期26卷 417-423页

作者： Zhenghua Qian Feng Jin Sohichi Hirose department of mechanical and environmental informatics Tokyo Institute of Technology Tokyo 152-8550 Japan MOE Key Laboratory for Strength and Vibration Xi'an Jiaotong University 710049 Xi'an China

The existence and propagation of transverse surface waves in piezoelectric coupled solids is investigated, in which perfect bonding between a metal/dielectric substrate and a piezoelectric layer of finite-thickness is assumed. Dis- persion equations relating phase velocity to material con- stants for the existence of various modes are obtained in a simple mathematical form for a piezoelectric material of class 6mm. It is discovered and proved by numerical examples in this paper that a novel Bleustein-Gulyaev （B-G） type of transverse surface wave can exist in such piezoelectric cou- pled solid media when the bulk-shear-wave velocity in the substrate is less than that in the piezoelectric layer but greater than the corresponding B-G wave velocity in the same pie- zoelectric material with an electroded surface. Such a wave does not exist in such layered structures in the absence of pie- zoelectricity. The mode shapes for displacement and electric potential in the piezoelectric layer are obtained and discussed theoretically. The study extends the regime of transverse sur- face waves and may lead to potential applications to surface acoustic wave devices.

关键词： Transverse surface wave Piezoelectric coupled solids - Dispersion relationSurface acoustic wave devices

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Global precision analysis of carrier phase relative positioning in BeiDou navigation satellite system and United States global positioning system

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Science China Earth Sciences 2019年第4期62卷 733-749页

作者： Letao ZHOU Dingfa HUANG Wei FENG Wu CHEN Xi ZHANG Li YAN department of Surveying and Geo-informatics Faculty of Geosciences and Environmental EngineeringSouthWest JiaoTong University department of Land Surveying and Geo-informatics Hong Kong Polytechnic University

In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion *** processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and *** analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards.

关键词： BeiDou navigation satellite system Relative positioning Dilution of precision Frequency dilution of precision Spatial-temporal availability

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A correlation between pulse diagnosis of human body and health monitoring of structures

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Earthquake Engineering and Engineering Vibration 2004年第1期3卷 117-125页

作者： C.C.Chang Henry T.Y.Yang department of Civil Engineering Hong Kong University of Science and TechnologyHong Kong Department of Mechanical and Environmental EngineeringUniversity of California department of mechanical and environmental Engineering University of California

The concept of health monitoring is a key aspect of the field of medicine that has been practiced for a long time. A commonly used diagnostic and health monitoring practice is pulse diagnosis, which can be traced back approximately five thousand years in the recorded history of China. With advances in the development of modern technology, the concept of health monitoring of a variety of engineering structures in several applications has begun to attract widespread attention. Of particular interest in this study is the health monitoring of civil structures. It seem natural, and even beneficial, that these two health-monitoring methods, one as applies to the human body and the other to civil structures, should be analyzed and compared. In this paper, the basic concepts and theories of the two monitoring methods are first discussed. Similarities are then summarized and commented upon. It is hoped that this correlation analysis may help provide structural engineers with some insights into the intrinsic concept of using pulse diagnosis in human health monitoring, which may of be some benefit in the development of modern structural health monitoring methods.

关键词： human health monitoring pulse diagnosis structural health monitoring vibration-based techniques local detection techniques

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Compliance Modeling and Analysis of a 3-RPS Parallel Kinematic Machine Module

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Chinese Journal of mechanical Engineering 2014年第4期27卷 703-713页

作者： ZHANG Jun ZHAO Yanqin DAI Jiansheng School of mechanical Engineering Anhui University of Technology department of informatics King's College London

The compliance modeling and rigidity performance evaluation for the lower mobility parallel manipulators are still to be remained as two overwhelming challenges in the stage of conceptual design due to their geometric complexities. By using the screw theory, this paper explores the compliance modeling and eigencompliance evaluation of a newly patented 1T2R spindle head whose topological architecture is a 3-RPS parallel mechanism. The kinematic definitions and inverse position analysis are briefly addressed in the first place to provide necessary information for compliance modeling. By considering the 3-RPS parallel kinematic machine（PKM） as a typical compliant parallel device, whose three limb assemblages have bending, extending and torsional deflections, an analytical compliance model for the spindle head is established with screw theory and the analytical stiffness matrix of the platform is formulated. Based on the eigenscrew decomposition, the eigencompliance and corresponding eigenscrews are analyzed and the platform＇s compliance properties are physically interpreted as the suspension of six screw springs. The distributions of stiffness constants of the six screw springs throughout the workspace are predicted in a quick manner with a piece-by-piece calculation algorithm. The numerical simulation reveals a strong dependency of platform＇s compliance on its configuration in that they are axially symmetric due to structural features. At the last stage, the effects of some design variables such as structural, configurational and dimensional parameters on system rigidity characteristics are investigated with the purpose of providing useful information for the structural design and performance improvement of the PKM. Compared with previous efforts in compliance analysis of PKMs, the present methodology is more intuitive and universal thus can be easily applied to evaluate the overall rigidity performance of other PKMs with high efficiency.

关键词： compliance modeling parallel kinematic machine eigencompliance eigenscrew

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Fabrication of bimetallic Ag/Fe immobilized on modified biochar for removal of carbon tetrachloride

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Journal of environmental Sciences 2017年第4期29卷 346-357页

作者： Hongwei Wu Qiyan Feng School of environmental Science and Spatial informatics China University of Mining and Technology department of Chemistry Zaozhuang University

As an effective conventional absorbent, biochar exhibited limited adsorption ability toward small hydrophobic molecules. To enhance the adsorption capacity, a novel adsorbent was prepared by immobilizing nanoscale zero-valent iron onto modified biochar（MB） and then the elemental silver was attached to the surface of iron（Ag/Fe/MB）. It＇s noted that spherical Ag/Fe nanoparticles with diameter of 51 nm were highly dispersed on the surface of MB. As the typical hydrophobic contaminant, carbon tetrachloride was selected for examining the removal efficiency of the adsorbent. The removal efficiencies of carbon tetrachloride by original biochar（OB）, Ag/Fe, Ag/Fe/OB and Ag/Fe/MB were fully investigated. It＇s found that Ag/Fe/MB showed higher carbon tetrachloride removal efficiency, which is about 5.5 times higher than that of the OB sample due to utilizing the merits of high adsorption and reduction. Thermodynamic parameters revealed that the removal of carbon tetrachloride by Ag/Fe/MB was a spontaneous and exothermic process, which was affected by solution p H, initial carbon tetrachloride concentration and temperature. The novel Ag/Fe/MB composites provided a promising material for carbon tetrachloride removal from effluent.

关键词： Bimetallic Ag/Fe nanoparticles Modified biochar Carbon tetrachloride

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