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Weighted Endpoint Estimates for Maximal Commutators Associated with the Sections

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Acta Mathematica Sinica,English Series 2010年第8期26卷 1463-1474页

作者： Jie cheng chen yan Dan zhang Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

We prove endpoint estimates for maximal commutators for a class of singular integral operators related to the real analysis of the Monge Ampere equation.

关键词： Weighted inequalities maximal commutators Monge-Ampere equation the sharp maximal function

Synthesis and co-luminescence properties of Tb^(3+)-methacrylic acid-1,10-phenanthroline complexes doped with Eu^(3+)

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Rare Metals 2012年第5期31卷 479-483页

作者： chen yan zhang Jing zhang Le HAN Pengde WANG Lixi zhang Qitu College of Materials Science and Engineering Nanjing University of Technology Nanjing 210009 China

A series of rare earth complexes Tb_(1-x)Eu_x(MAA)_3phen(x=0.00, 0.01, 0.03, 0.05, 0.07, 0.09, 0.10, 0.30, and 0.50) were synthesized with MAA as the first ligand and phen as the second ligand. The complexes were characterized by means of FT-IR, thermogravimetry-differential scanning calorimetry (TG-DSC), XRD, UV absorption spectra, and photoluminescence spectra (PL). The results show that the luminescence intensity of Eu^(3+)increases as Tb^(3+) transfer the absorbed energy to Eu^(3+) in the complexes. The emission of Tb^(3+) at 545 nm is observed and increasing with x decreasing. When x=0.01, the luminescence intensity reaches the maximum value, and the emission intensity of Tb 3+ at 545 nm and Eu^(3+) at 614 nm are almost equal. It realizes the co-luminescence of Eu^(3+) and Tb^(3+) . We can obtain complexes with different colors by adjusting the ratio of Eu^(3+) to Tb^(3+) .

关键词： rare earths complexes luminescent intensity co-luminescence

A New Certificateless Public Key Encryption Scheme

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Wuhan University Journal of Natural Sciences 2008年第6期13卷 721-726页

作者： chen yan zhang Futai School of Mathematics and Computer Science Nanjing Normal University Nanjing 210097 Jiangsu China

Certificateless public key cryptography （CL-PKC） enjoys the advantage of identity based cryptography without suffering from its inherent key escrow problem. In this paper, a new efficient certificateless public key encryption scheme is proposed and its security can reach chosen-ciphertext （CCA2） secure in the random oracle model assuming the CDH and p-BDHI problem are difficult. A comparison shows that the efficiency of the proposed scheme is better than all known paring-based certificateless public key encryption schemes in the random oracle model.

关键词： certificateless public key encryption bilinear maps provable security

Synthesis and magnetic properties of CoPt nanoparticles

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Rare Metals 2006年第z1期25卷 613-616页

作者： zhang Zhongyan WANG Hao WANG Hanbin MO Qi chen yan zhang Cong Faculty of Physics and Electronic Technology Hubei UniversityWuhan 430062China

CoPt nanoparticles were prepared by simultaneous thermally reducing Co(CH_(3)COO)_(2)and Pt(acac)_(2)in oleylamine with a small quantity of oleic *** composition of the particles was controlled by changing the amount of the *** electronic microscopy reveals that Co_(48)Pt_(52)particles with an average diameter of 8.4 nm are steadily dispersed in octane in the presence of oleylamine and oleic *** area electron diffraction indicates that the as-prepared particles have a face center cubic *** properties of these particles measured by a vibrate sample magnetometer yield a coercivity of 1.194×10^(4)A·m^(-1)and a saturation magnetization of 5.3 emu·g^(-1).After annealing at 650℃for 2 h under the flowing Ar,the coercivity increases to 9.552×10^(4)A·m^(-1)according to partly phase transformation from face center cubic structure to face center tetragonal structure for the nanoparticles.

关键词： magnetic media nanoparticles CoPt

Secure Proxy Re-Encryption from CBE to IBE

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Wuhan University Journal of Natural Sciences 2008年第6期13卷 657-661页

作者： chen yan zhang Futai School of Mathematics and Computer Science Nanjing Normal University Nanjing 210097 Jiangsu China

In this paper, an efficient hybrid proxy re-encryption scheme that allows the transformation of the ciphertexts in a traditional public key cryptosystem into the ciphertexts in an identity-based system is proposed. The scheme is non-interactive, unidirectional and collude ＂safe＂. Furthermore, it is compatible with current IBE （identity-based encryption） deployments. The scheme has chosen ciphertext security in the random oracle model assuming the hardness of the Decisional Bilinear Diffie-Hellman problem.

关键词： proxy re-encryption traditional public key encryption identity-based public key encryption Decisional Bilinear Diffie-Hellman problem random oracle model

Velocity-Incorporated Wear Model of Rolling Guide Shoe Material Selection

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 118-135页

作者： Longye chen Lingyu yan chengliang Liu Zhinan zhang School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China

To ensure an accurate selection of rolling guide shoe materials,an analysis of the intricate relationship between linear speed and wear is *** element simulations and experimental measurements are employed to evaluate four distinct types of materials:polyurethane,rubber,polytetrafluoroethylene(PTFE),and *** speed-index of each material is measured,serving as a preparation for subsequent ***,the velocity-wear factor is determined,providing insights into the resilience and durability of the material across varying ***,a wear model tailored specifically for viscoelastic bodies is explored,which is pivotal in understanding the wear mechanisms within the *** this model,wear predictions are made under higher speed conditions,facilitating the choice of material for rolling guide *** validate the accuracy of the model,the predicted degree of wear is compared with experimental data,ensuring its alignment with both theoretical principles and real-world *** comprehensive analysis has verified the effectiveness of the model in the selection of materials under high-speed conditions,thereby offering confidence in its reliability and ensuring optimal performance.

关键词： Archard model Wear model Speed-index Wear prediction

Thin paints for durable and scalable radiative cooling

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Journal of Energy Chemistry 2024年第3期90卷 176-182,I0006页

作者： Shanquan Liu Fei zhang Xingyu chen Hongjie yan Wei chen Meijie chen School of Energy Science and Engineering Central South UniversityChangsha 410083HunanChina School of Intelligent Manufacturing Ecosystem Xi'an Jiaotong-Liverpool UniversitySuzhou 215400JiangsuChina

Passive daytime radiative cooling(PDRC) is environment-friendly without energy input by enhancing the coating's solar reflectance(R_(solar)) and thermal emittance(ε_(LWIR)) in the atmosphere's long-wave infrared transmission ***,high R_(solar) is usually achieved by increasing the coating's thickness,which not only increases materials' cost but also impairs heat ***,the desired high R_(solar) is vulnerable to dust pollution in the *** this work,a thin paint was designed by mixing hBN plates,PFOTS,and IPA. R_(solar)=0.963 and ε_(LWIR)=0.927 was achieved at a thickness of 150 μm due to the high backscattering ability of scatters.A high through-plane thermal conductivity(~1.82 W m^(-1) K^(-1)) also can be *** addition,the porous structure coupled with the binder PFOTS resulted in a contact angle of 154°,demonstrating excellent durability under dust *** experiments showed that the thin paint can obtain a 2.3℃ lower temperature for sub-ambient cooling than the reference PDRC coating in the ***,the above-ambient heat dissipation performance can be enhanced by spraying the thin paint on a 3D heat sink,which was 15.7℃ lower than the reference 1D structure,demonstrating excellent performance for durable and scalable PDRC applications.

关键词： Radiative cooling Heat dissipation Solar reflectance Thermal emittance Contact angle

Balancing Exploration–Exploitation of Multi-verse Optimizer for Parameter Extraction on Photovoltaic Models

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Journal of Bionic Engineering 2024年第2期21卷 1022-1054页

作者： yan Han Weibin chen Ali Asghar Heidari Huiling chen Xin zhang College of Computer Science and Artificial Intelligence Wenzhou UniversityWenzhou325035China School of Surveying and Geospatial Engineering College of EngineeringUniversity of TehranTehranIran School of Biomedical Engineering National Engineering Research Center of Ophthalmology and OptometryEye HospitalWenzhou Medical UniversityWenzhou325027China Key Lab of Biohealth Materials and Chemistry of Wenzhou Wenzhou UniversityWenzhouChina Key Laboratory of Intelligent Informatics for Safety&Emergency of Zhejiang Province Wenzhou UniversityWenzhouChina

Extracting photovoltaic(PV)model parameters based on the measured voltage and current information is crucial in the simulation and management of PV *** accurately and reliably extract the unknown parameters of different PV models,this paper proposes an improved multi-verse optimizer that integrates an iterative chaos map and the Nelder–Mead simplex method,*** experiments verified that the proposed INMVO fueled by both mechanisms has more affluent populations and a more reasonable balance between exploration and ***,to verify the feasibility and competitiveness of the proposal,this paper employed INMVO to extract the unknown parameters on single-diode,double-diode,three-diode,and PV module four well-known PV models,and the high-performance techniques are selected for *** addition,the Wilcoxon signed-rank and Friedman tests were employed to test the experimental results *** evaluation metrics,such as root means square error,relative error,absolute error,and statistical test,demonstrate that the proposed INMVO works effectively and accurately to extract the unknown parameters on different PV models compared to other *** addition,the capability of INMVO to stably and accurately extract unknown parameters was also verified on three commercial PV modules under different irradiance and *** conclusion,the proposal in this paper can be implemented as an advanced and reliable tool for extracting the unknown parameters of different PV *** that the source code of INMVO is available at https://***/woniuzuioupao/INMVO.

关键词： Photovoltaic models Multi-verse optimizer Nelder-Mead simplex Iterative chaos map

Multi-blade rubbing characteristics of the shaft-disk-blade-casing system with large rotation

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 111-136页

作者： Zhiyuan WU Linchuan ZHAO Han yan Ge yan Ao chen Wenming zhang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of Aerospace Systems Engineering Shanghai 201108China

Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the blade, while some only consider the whirl of the rotor, neglecting its spin. To address these limitations, this paper proposes a dynamic model with large rotation for the SDBC system. The model incorporates the spin and whirl of the rotor, enabling the realistic reproduction of multiblade rubbing faults. To verify the accuracy of the SDBC model with large rotation and demonstrate its capability to effectively consider the rotational effects such as the centrifugal stiffening and gyroscopic effects, the natural characteristics and dynamic responses of the proposed model are compared with those obtained from reported research and experimental results. Furthermore, the effects of the rotating speed, contact stiffness,and blade number on the dynamic characteristics of the SDBC system with multi-blade rubbing are investigated. The results indicate that the phase angle between the rotor deflection and the unbalance excitation force increases with the increasing rotating speed,which significantly influences the rubbing penetration of each blade. The natural frequency of the SDBC system with rubbing constrain can be observed in the acceleration response of the casing and the torsional response of the shaft, and the frequency is related to the contact stiffness. Moreover, the vibration amplitude increases significantly with the product of the blade number under rubbing, and the rotating frequency approaches the natural frequency of the SDBC system. The proposed model can provide valuable insight for the fault diagnosis of rubbing in bladed rotating machinery.

关键词： shaft-disk-blade-casing(SDBC) large rotation spin and whirl multi-blade rubbing rotational effect