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Fast Two-dimensional Positioning Method of Crab Pulsar Based on Multiple Optimization Algorithms

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Research in Astronomy and Astrophysics 2024年第10期24卷 92-103页

作者： Jianfeng Chen jin Liu Xin Ma Xiaolin ning College of Information Science and Engineering Wuhan University of Science and TechnologyWuhan 430081China School of Instrumentation Science and Opto-electronics Engineering Beihang UniversityBeijing 100191China Hefei National Laboratory Hefei 230088China

In the two-dimensional positioning method of pulsars, the grid method is used to provide non-sensitive direction and positional estimates. However, the grid method has a high computational load and low accuracy due to the interval of the grid. To improve estimation accuracy and reduce the computational load, we propose a fast twodimensional positioning method for the crab pulsar based on multiple optimization algorithms(FTPCO). The FTPCO uses the Levenberg–Marquardt(LM) algorithm, three-point orientation(TPO) method, particle swarm optimization(PSO) and Newton–Raphson-based optimizer(NRBO) to substitute the grid method. First, to avoid the influence of the non-sensitive direction on positioning, we take an orbital error and the distortion of the pulsar profile as optimization objectives and combine the grid method with the LM algorithm or PSO to search for the non-sensitive direction. Then, on the sensitive plane perpendicular to the non-sensitive direction, the TPO method is proposed to fast search the sensitive direction and sub-sensitive direction. Finally, the NRBO is employed on the sensitive and sub-sensitive directions to achieve two-dimensional positioning of the Crab pulsar. The simulation results show that the computational load of the FTPCO is reduced by 89.4% and the positioning accuracy of the FTPCO is improved by approximately 38% compared with the grid method. The FTPCO has the advantage of high real-time accuracy and does not fall into the local optimum.

关键词： (stars:)pulsars:individual(Crab pulsar) space vehicles methods:data analysis astrometry

Reduced Macrophage Uptake of Nanoparticles through Surface Modification of Polypeptides with Valine Residues

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Chinese Journal of Chemistry 2024年第11期42卷 1209-1216页

作者： ning Li Shanshan Xiao Xiaoxiong jin Ziyuan Song Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhouJiangsu215123 China

The structural and surface properties of nanomedicines play an important role in determining their biological fate. Surface chemistry of nanomedicines is one of the key parameters, where researchers used various strategies such as PEGylation to avoid the undesired clearance of nanoparticles (NPs) for enhanced targeting effect. Nevertheless, the fine-tuning of surface chemistry through polymer functionalization remains largely unexplored. In this concise report, we find that the incorporation of only 10 mol% valine residues into the surface-anchored poly(L-glutamic acid) significantly lowered the macrophage uptake of NPs. The introduction of other hydrophobic amino acid residues, however, increased the NPs internalization instead. The chirality and the side-chain structure of valine played an important role in the unexpected uptake behavior. We believe this work highlights the impact of slight changes of the surface-anchored polymer structure on the behavior of NPs, drawing people's attention to the careful design of surface chemistry to optimize the nanomedicine design.

关键词： Nanoparticles Copolymers Structure-activity relationships Surface chemistry Polypeptide Macrophage uptake

Improvement of the piezoelectricity of PVDF-HFP by CoFe_(2)O_(4)nanoparticles

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Nano Materials Science 2024年第2期6卷 201-210页

作者： Dan Lei ning Hu Liangke Wu Alamusi Huiming ning Yang Wang Zhaonan jin Yaolu Liu College of Aerospace Engineering Chongqing UniversityChongqing400044China State Key Laboratory of Reliability and Intelligence Electrical Equipment School of Mechanical EngineeringHebei University of TechnologyTianjin300401China

High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field *** decisive effect of the poling electric field on the power generating capability was confirmed by the *** pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity *** the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 ***,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,*** effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC.

关键词： PVDF-HFP CoFe_(2)O_(4)nanoparticles Piezoelectricity Nanocomposite

High-resolution remote thermometry based on Bi^(3+)-doped 0D zinc halide hybrids

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Science China Chemistry 2024年第8期67卷 2599-2605页

作者： Cui-Mi Shi Shu-Hua Xue jin-Yun Wang Liang-jin Xu Zhong-ning Chen State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Science Technology Innovation Laboratory for Optoelectronic Information of ChinaFuzhou 350108China University of Chinese Academy of Sciences Beijing 100049China

Developing highly sensitive optical thermometers is of great significance due to their capability to enable remote and non-contact temperature measurements, rendering them highly applicable in diverse and harsh environments. Herein we report a temperature-dependent phosphor of 0D metal halide hybrid by incorporating Bi^(3+)into the(MePPh_(3))_(2)ZnCl_(4) matrix. Through Bi^(3+)doping,the initially non-luminescent(MePPh_(3))_(2) ZnCl_(4) matrix exhibits a deep-blue emission centered at 453 nm, with a photoluminescence quantum yield(PLQY) of 5.71% and a Stokes shift of 75 nm at room temperature. Experimental characterization demonstrates that exciton-like luminescence of Bi^(3+)is mainly responsible for the blue emission. Single crystals of Bi^(3+)-doped(MePPh_(3))_(2)ZnCl_(4) show an unusual correlation between photoluminescence(PL) lifetime and temperature. Particularly, the dependence of luminescence lifetime on temperature is most remarkable in the temperature range of 80 to 100 K with an exceptional sensitivity up to 0.09 K^(-1), representing one of the best levels for thermometry based on PL decay lifetime. Our work not only provides a viable strategy for designing a novel, environmentally friendly, and stable blue emitter, but also paves the way for precise thermometric application at low temperature.

关键词： lead-free hybrids Bi^(3+)doping blue emission temperature sensing

Exploration on electrical resistance tomography in characterizing the slurry spatial distribution in cemented granular materials

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Frontiers of Structural and Civil Engineering 2024年第3期18卷 365-379页

作者： Bohao WANG Wei WANG Feng jin Handong TAN ning LIU Duruo HUANG State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China Institute of Science and Technology China Three Gorges CorporationBeijing 100038China School of Geophysics and Information Technology China University of GeosciencesBeijing 100083China

This study investigated the application of electrical resistance tomography(ERT)in characterizing the slurry spatial distribution in cemented granular materials(CGMs).For CGM formed by self-flow grouting,the voids in the accumulation are only partially filled and the bond strength is often limited,which results in difficulty in obtaining in situ samples for quality ***,it is usually infeasible to evaluate the grouting effect or monitor the slurry spatial distribution by a mechanical *** this research,the process of grouting cement paste into high alumina ceramic beads(HACB)accumulation is reliably monitored with *** shows that ERT results can be used to calculate the cement paste volume in the HACB accumulation,based on calibrating the saturation exponent n in Archie’s *** results support the feasibility of ERT as an imaging tool in CGM characterization and may provide guidance for engineering applications in the future.

关键词： electrical resistance tomography cemented granular material grouting spatial distribution Archie’s law

Multiplicity of solutions for the semilinear subelliptic Dirichlet problem

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Science China Mathematics 2024年第3期67卷 475-504页

作者： Hua Chen Hong-Ge Chen jin-ning Li Xin Liao School of Mathematics and Statistics Wuhan UniversityWuhan 430072China Wuhan Institute of Physics and Mathematics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China

In this paper,we study the semilinear subelliptic equation{−△Xu=f(x,u)+g(x,u)inΩ,u=0 on∂Ω,where△X=−∑m i=1 Xi∗Xi is the self-adjoint Hormander operator associated with the vector fields X=(X_(1),X_(2),...,X_(m))satisfying the Hormander's condition,f(x,u)∈C(Ω×R),g(x,u)is a Carathéodory function onΩ×R,andΩis an open bounded domain in R~n with smooth *** the perturbation from the symmetry method with the approaches involving the eigenvalue estimate and the Morse index in estimating the minimax values,we obtain two kinds of existence results for multiple weak solutions to the problem ***,we discuss the difference between the eigenvalue estimate approach and the Morse index approach in degenerate *** with the classical elliptic cases,both approaches here have their own strengths in the degenerate *** new phenomenon implies that the results in general degenerate cases would be quite different from the situations in classical elliptic cases.

关键词： degenerate elliptic equations Hormander operators perturbation method Morse index

Distributions of Visual Receptive Fields from Retinotopic to Craniotopic Coordinates in the Lateral Intraparietal Area and Frontal Eye Fields of the Macaque

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Neuroscience Bulletin 2024年第2期40卷 171-181页

作者： Lin Yang Min jin Cong Zhang ning Qian Mingsha Zhang Key Laboratory of Cognitive Neuroscience and Learning Division of PsychologyBeijing Normal UniversityBeijing 100875China Institute of Neuroscience Key Laboratory of Primate NeurobiologyCAS Center for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesShanghai 200031China Department of Neuroscience and Zuckerman Institute Columbia UniversityNew York 10027USA

Even though retinal images of objects change their locations following each eye movement,we perceive a stable and continuous *** possible mechanism by which the brain achieves such visual stability is to construct a craniotopic coordinate by integrating retinal and extraretinal *** have been several proposals on how this may be done,including eye-position modulation(gain fields)of retinotopic receptive fields(RFs)and craniotopic *** the present study,we investigated coordinate systems used by RFs in the lateral intraparietal(LIP)cortex and frontal eye fields(FEF)and compared the two *** mapped the two-dimensional RFs of neurons in detail under two eye fixations and analyzed how the RF of a given neuron changes with eye position to determine its coordinate *** same recording and analysis procedures were applied to the two brain *** found that,in both areas,RFs were distributed from retinotopic to craniotopic *** was no significant difference between the distributions in the LIP and *** a small fraction of neurons was fully craniotopic,whereas most neurons were between the retinotopic and craniotopic *** distributions were strongly biased toward the retinotopic side but with significant craniotopic *** results suggest that there is only weak evidence for craniotopic RFs in the LIP and FEF,and that transformation from retinotopic to craniotopic coordinates in these areas must rely on other factors such as gain fields.

关键词： Reference frames Eye-centered Headcentered Visual stability

Stereoselective Self-Assembly of Chiral Metalla[2]Catenanes and Lemniscular Macrocycles

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CCS Chemistry 2024年第8期6卷 2000-2010页

作者： Shu-jin Bao Hai-ning Zhang Guo-Xin jin Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials State Key Laboratory of Molecular Engineering of PolymersDepartment of ChemistryFudan UniversityShanghai 200433

Designing and stereoselectively constructing chiral mechanically interlocked molecules(MIMs)is a goal that many chemists are pursuing due to their potential in the development of functional molecular machines involved in catalysis,sensing,and chiroptical ***,the synthesis of enantiopure supramolecular entities with crystallographic structures remains ***,the stereoselective self-assembly of chiral metalla[2]catenanes interlocked by two D-shaped macrocycles was realized by combining long binuclear half-sandwich organometallic Cp*Rh^(III)(Cp*=η^(5)-pentamethylcyclopentadienyl)clip and ditopic monodentate ligand incorporating L-leucine *** resulting metalla[2]catenane displayed unique co-conformational mechanical helical chirality characteristics arising from the chirality transfer of the chiral ***,decreasing the length of the binuclear Cp*Rh^(III)clip and adjusting the steric hindrance of the amino-acid side chains(L-alanine and L-phenylalanine)in the ligands resulted in two lemniscular macrocycles with left-handed(M)-twisted conformational *** the best of our knowledge,the synthesized macrocycles are the first family of homochiral abnormal lemniscate-shaped organometallic macrocycles featuring figure-eight ***[2]catenanes and macrocycles with opposite chirality were also generated by employing corresponding D-amino acid ligands,as evidenced by single-crystal X-ray diffraction,nuclear magnetic resonance,mass,and circular dichroism *** present study demonstrates that homochiral MIMs can be accessed readily using amino acid–containing ligands through rational molecular design.

关键词： stereoselective synthesis chirality metallacatenanes twisted macrocycles aminoacid residues

Coordination-driven self-assembly of a molecular 818knot and molecular borromean rings

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Science China Chemistry 2024年第11期67卷 3652-3656页

作者： Xiang Gao Dong Liu Hai-ning Zhang Guo-Xin jin Department of Chemistry Fudan University

We report the facile construction of a molecular 818knot and a molecular Borromean rings assembly through self-assembly directed by Cp*Rh corner units. Two curved ligands of similar size and shape were used in this study. The slight steric differences between the two ligands induce the formation of distinctly different topologies of the assembled products. The structures were confirmed by single-crystal X-ray analysis and nuclear magnetic resonance spectroscopy.

关键词： coordination-driven Cp*Rh 818 knot Borromean rings