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Filament geometrical model and nozzle trajectory analysis in the fused deposition modeling process

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 370-376页

作者： yu-zhen jin Jia-fan ZHANG Ying WANG Zu-chao ZHU State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China Faculty of Mechanical Engineering & Automation Zhejiang Sci- Tech University Hangzhou 310018 China

The geometrical model of the filament during the fused deposition modeling (FDM) process was firstly proposed based on three different models, tractrix, parabola, and catenary. Comparing with the actual measured filament curves on the Stratasys 1600 FDM machine, it is indicated that the tractrix model had the best agreement with the actual measured curves. With the analytical simulation, the nozzle trajectories in the straight-line deposition road, circle road, and arbitrary continuous curve road were deduced, according to the traxtric based geometrical model of the filament.

关键词： Fused deposition modeling (FDM) Filament geometrical model Nozzle trajectory

The first observation and data reduction of the Multi-wavelength Spectrometer on the New Vacuum Solar Telescope

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Research in Astronomy and Astrophysics 2013年第10期13卷 1240-1254页

作者： Rui Wang Zhi Xu zhen-yu jin Zhi Li yu Fu Zhong Liu yunnan Astronomical Observatory / National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences

The Multi-wavelength Spectrometer is a medium-dispersion（R^130 000）grating spectrometer installed on the New Vacuum Solar Telescope at the Fuxian Solar Observatory,yunnan Astronomical Observatory,Chinese Academy of *** is designed to accurately observe the velocity and magnetic fields of the *** present configuration of this spectrometer allows us to simultaneously observe three different solar spectral *** work is dedicated to showing the first observations carried out in both the Hαand Ca II 8542 A *** give a detailed description of the data reduction process,focusing on the retrieval of a flat field from the high-resolution spectral *** different methods are also performed and compared to eliminate the residual fringe in the reduced *** real spectral resolution and instrumental profile are analyzed based on the final results,which indicate that this spectrometer presently satisfies the expected performance and it is ready for further scientific observations.

关键词： instrumentation:spectrographs techniques:spectroscopic Sun:chromosphere

A novel hexapod and its prototype for secondary mirror alignment in telescopes

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Research in Astronomy and Astrophysics 2018年第9期18卷 113-122页

作者： De-Hua Yang Ying Cheng Chang-Cheng Wu Fei Fei zhen-yu jin College of Automation Engineering Nanjing University of Aeronautics and Astronautics yunnan Observatories Chinese Academy of Sciences

This paper presents a novel hexapod as the adjustment mechanism for a telescope to actively align its secondary mirror. The special hexapod provides six degrees of freedom（6-DOFs） with decoupled translation and rotation. The decoupled kinematic motions are analyzed and commented on as the alignment mechanism of a secondary mirror from an optical alignment point of view. In terms of performance of the adjustment generally required by the secondary mirror in a telescope, we developed a prototype that uses a novel hexapod design with linear micro-displacement actuators. Especially, in order to achieve high precision, flexures were used to build joints for the hexapod to minimize frictions and eliminate backlashes. Based on the specific configuration and dimension of the prototype hexapod,an analytical model of the reachable workspace was built with the constraints defined by limited rotation angles of the flexure-based joints. We used a laser tracker to verify that the hexapod can reach a spherical translation workspace of φ6 mm and a rotation workspace of±1°. The translational repeatability was tested to be around half a μm by laser displacement sensors. In addition, we also measured the axial and lateral stiffnesses of the hexapod to be around 5500 N mm-^1 and 1750 N mm^-1, respectively. The kinematic analyses and convincing test results jointly encourage implementing the novel hexapod design with decoupled translation and rotation as a favorable alignment mechanism for secondary mirrors in astronomical telescopes.

关键词： telescopes --methods analytical - methods miscellaneous - techniques miscellaneous

Dynamic Regulation of Hydrogen Bonding Networks and Solvation Structures for Synergistic Solar‑Thermal Desalination of Seawater and Catalytic Degradation of Organic Pollutants

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Nano-Micro Letters 2025年第2期17卷 548-565页

作者： Ming‑yuan yu jing Wu Guang Yin Fan‑zhen Jiao Zhong‑zhen yu jin Qu Beijing Key Laboratory of Advanced Functional Polymer Composites Beijing University of Chemical TechnologyBeijing 100029People’s Republic of China State Key Laboratory of Organic‑Inorganic Composites College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China

Although solar steam generation strategy is efficient in desalinating seawater,it is still challenging to achieve continuous solar-thermal desalination of seawater and catalytic degradation of organic ***,dynamic regulations of hydrogen bonding networks and solvation structures are realized by designing an asymmetric bilayer membrane consisting of a bacterial cellulose/carbon nanotube/Co_(2)(OH)_(2)CO_(3)nanorod top layer and a bacterial cellulose/Co_(2)(OH)_(2)CO_(3)nanorod(BCH)bottom ***,the hydrogen bonding networks inside the membrane can be tuned by the rich surface–OH groups of the bacterial cellulose and Co_(2)(OH)_(2)CO_(3)as well as the ions and radicals in situ generated during the catalysis ***,both SO_(4)^(2−)and HSO_(5)−can regulate the solvation structure of Na^(+)and be adsorbed more preferentially on the evaporation surface than Cl^(−),thus hindering the de-solvation of the solvated Na^(+)and subsequent nucleation/growth of ***,the heat generated by the solar-thermal energy conversion can accelerate the reaction kinetics and enhance the catalytic degradation *** work provides a flow-bed water purification system with an asymmetric solar-thermal and catalytic membrane for synergistic solar thermal desalination of seawater/brine and catalytic degradation of organic pollutants.

关键词： Solar steam generation Seawater desalination Catalytic degradation Bacterial cellulose Cobalt hydroxycarbonate nanorods

The Co-alignment of Winged HαData Observed by the New Vacuum Solar Telescope

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Research in Astronomy and Astrophysics 2022年第6期22卷 101-108页

作者： yun-Fang Cai Xu Yang Yong-yuang Xiang Xiao-Li Yan zhen-yu jin Hui Liu Kai-Fan Ji yunnan Observatories Chinese Academy of SciencesKunming 650011China Big Bear Solar Observatory New Jersey Institute of Technology40386 North Shore LaneBig Bear CityCA92314USA

The New Vacuum Solar Telescope(NVST)has been releasing its novel winged Hαdata(WHD)since 2021 April,namely the Hαimaging spectroscopic *** with the prior released version,the new data are further coaligned among the off-band images and packaged into a standard solar physics community *** this study,we illustrate the alignment algorithm used by the novel WHD,which is mainly based on the optical flow method to obtain the translation offset between the winged *** quantitatively evaluate the alignment results of two images with different similarities,we calculate the alignment accuracies between the images of different off-band and line center,*** result shows that our alignment algorithm could reach up to the accuracy of about 0.″1 when the off-band of winged image is lower than 0.6?.In addition,we introduce the final product of the WHD in detail,which can provide convenience for the solar physicists to use high-resolution Hαimaging spectroscopic data of NVST.

关键词： Sun:atmosphere methods:data analysis-techniques:imaging spectroscopy-techniques image processing

Spectro-polarimetric observations at the NVST:*** polarization calibration and primary measurements

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Research in Astronomy and Astrophysics 2020年第4期20卷 7-18页

作者： Jun-Feng Hou Zhi Xu Shu yuan yu-Chao Chen Jian-Guo Peng Dong-Guang Wang Jun Xu yuan-Yong Deng zhen-yu jin Kai-Fan Ji Zhong Liu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China yunnan Observatories Chinese Academy of SciencesKunming 650216China

This paper is devoted to the primary spectro-polarimetric observation performed at the New Vacuum Solar Telescope(NVST)of China since 2017,and our aim is to precisely evaluate the real polarimetric accuracy and sensitivity of this polarimetry by using full Stokes spectro-polarimetric observations of the photospheric line Fe I 532.4 *** the work,we briefly describe the salient characteristic of the NVST as a polarimeter in terms of technology and then characterize its instrumental polarization based on the operation in 2017 and *** is verified that the calibration method utilizing the instrumental polarization calibration unit(ICU)is stable and *** calibration accuracy can reach up to 3×10^-*** on the scientific observation of NOAA Active Region 12645 on 2017 April 5,we estimate that the residual cross-talk from Stokes I to Stokes Q,U and V,after the instrumental polarization calibration,is about 4×10^-3 on average,which is consistent with the calibration accuracy and close to the photon *** polarimetric sensitivity(i.e.,the detection limit)for polarized light is of the order of 10-3 with an integration time over 20 *** modulation rate is indeed an issue for the present *** present NVST polarimeter is expected to be integrated with a high-order adaptive optics system and a field scanner to realize 2 D vector magnetic field measurements in the following instrumentation update.

关键词： techniques:polarimetric techniques:spectroscopic Sun:magnetic fields

Local magnetic moment oscillation around an Anderson impurity on graphene

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 192-201页

作者： Shuai Li zhen Ma jin-Hua Gao School of Science Hebei University of Science and Technology School of Electronics and Information Zhengzhou University of Light Industry School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology

We theoretically investigate the spin resolved Friedel oscillation （FO） and quasiparticle interference （QPI） in graphene induced by an Anderson *** the impurity becomes magnetic,the resulted FO becomes spin dependent,which gives rise to a local magnetic moment oscillation with an envelop decaying as r-2in real space in the doping ***,at half filling,the electron density and local magnetic moment will not oscillate but decay as *** spin resolved FO has both sublattice and spin ***,the local magnetic moment decay at half filling only occurs at one sublattice of graphene,which is quite like the phenomenon observed in the STM experiment (***ález-Herrero et al.,Science 352,437 （2016）).We further give an analytic formula about such spin dependent FO based on the stationary phase ***,we study the interference of quasiparticles around the magnetic impurity by calculating the spin dependent Fourier-transformed local density of states （FT-LDOS）.Our work gives a comprehensive understanding about the local magnetic moment oscillation around an Anderson impurity on graphene.

关键词： Friedel oscillation local magnetic moment graphene Anderson impurity

Integration of Electrical Properties and Polarization Loss Modulation on Atomic Fe–N‑RGO for Boosting Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 517-532页

作者： Kaili Zhang yuefeng Yan zhen Wang Guansheng Ma Dechang Jia Xiaoxiao Huang yu Zhou State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001People’s Republic of China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China MIIT Key Laboratory of Advanced Structural‑Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001People’s Republic of China

Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)*** on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible ***,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted *** composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA *** results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural ***,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy *** study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.

关键词： Electromagnetic wave absorption Fe-N-RGO Dipole polarization Conduction loss Impedance matching

Broadband and perfect terahertz absorber based on multilayer metamaterial with cross-ring patterned structures

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Optoelectronics Letters 2025年第1期21卷 1-6页

作者： WEN jin LIU Zhanzhi WU zhengwei PAN yu ZHANG Ying School of Science Xi'an Shiyou University Shaanxi Key Laboratory of Measurement and Control Technology for Oil and Gas Wells

Broadband and perfect terahertz absorber based on multilayer metamaterial using cross-ring patterned structures is proposed and investigated. The structure of the absorber is double absorption layers consisting of a chromium cross ring and eight isosceles right triangles. The unique structure of the double absorbing layers excites the electric dipole multimode resonance, giving rise to high absorption performance. Meanwhile, the influence of construal parameters on absorber behavior is also discussed. The numerical results show that the absorption achieves over 90% ranging from 2.45 THz to 6.25 THz and 99% absorption in the range of 3.7—5.3 THz. The realization of broadband and perfect absorber is described using the impedance matching principle. It is obviously found that the absorber is insensitive to the high angle of incidence for both transverse electric(TE) and transverse magnetic(TM) polarizations. Compared with the former reports, this absorber has remarkable improved absorption efficiency and smaller period. The terahertz absorber may be found applications in the fields of energy capture and thermal detection.

关键词： Metamaterials