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Investigating the Absorption and Desorption Behavior of Methylene Chloride in the Poly(aryl ether ketone) Film with Different Crystallinities

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Chinese Journal of Polymer Science 2024年第2期42卷 239-246,I0009页

作者： Hong-Ru Yang Jin-dong Zhang dong-Ting Gao Gang liu Chun-Hai Chen Jia-Nan Yao Center for Advanced Low-Dimension Materials State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620China

Poly(aryl ether keton e)(PAEK) films with different crystallinities were obtained by controlling the cooling rate,which were subjected to the absorption and desorption of methylene chloride(CH_(2)Cl_(2)).We employed attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy analyses to investigate the diffusion behavior of CH_(2)Cl_(2) in PAEK films with different *** to the Fickian diffusion model,the calculated diffu sion coefficients of CH_(2)Cl_(2) in PAEK films were observed to decrease with increasing *** effect of CH_(2)Cl_(2)absorption and desorption on the mechanical properties of PAEK films with different crystallinity was further analyzed using tensile *** tensile tests exhibited that CH_(2)Cl_(2) has two concurrent effects:plasticization and solvent-induced *** scanning calorimetry(DSC) and wide-angle X-ray diffraction(WXRD) techniques further confirmed solvent-induced crystallization *** results would be beneficial to understand the solvent resistance of PAEK materials and consequently provide the practical application conditions of PAEK with a theoretical basis.

关键词： Poly(aryl ether ketone) Diffusion behavior Infrared spectra Solvent-induced crystallization Mechanical properties

Strength and ductility optimization of HPDC AlSi8MgCuZn2 alloys by modifying pre-aging treatment

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China Foundry 2024年第4期21卷 343-351页

作者： Yuan-hang Jiang Hui-ting Zheng Fei liu Hai-dong Zhao National Engineering Research Center of Near-net Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510641China

Considering the components produced by high pressure die casting(HPDC)process usually with ultra-large sizes and complex morphologies,high temperature solid solution treatment is not a suitable method to further improve their mechanical *** this study,two-stage aging treatment with different pre-aging times was designed and employed to further improve the mechanical properties of HPDC Al8SiMgCuZn *** characteristics of precipitates were evaluated by a transmission electron microscope(TEM),and the precipitation strengthening mechanism was *** results reveal that the strengthening is mainly contributed by the precipitation ofβ″phase after two-stage aging,and the number density and size of the precipitates are significantly depended on the pre-aging *** number density of precipitates is increased with the pre-aging time prolonged from 0 h to 4 h,and then decreases with the further increase of pre-aging time from 4 h to 6 *** precipitates with the highest density and smallest size are observed after pre-aging for 4 *** pre-aged at 100℃for 4 h and then artificial aged at 200℃for 30 min,the yield strength of 207 MPa,ultimate tensile strength of 325 MPa and elongation of 7.6%are achieved.

关键词： high pressure die cast aluminum alloy microstructural heterogeneity mechanical properties precipitation strengthening two-stage aging

On the Responsible Use of Chatbots in Bioinformatics

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Genomics, Proteomics & Bioinformatics 2024年第1期22卷 1-3页

作者： Gangqing Hu Li liu dong Xu Department of Microbiology Immunology&Cell BiologyWest Virginia UniversityMorgantownWV 26506USA College of Health Solutions Arizona State UniversityPhoenixAZ 85004USA Biodesign Institute Arizona State UniversityTempeAZ 85281USA Department of Electrical Engineer and Computer Science Christopher S.Bond Life Sciences CenterUniversity of MissouriColumbiaMO 65211USA

Large language model(LLM)-based chatbots like Chat Generative Pre-trained Transformer(ChatGPT),equipped with broad biological knowledge[1],have demonstrated an impressive capability for bioinformatics coding[2].When given well-crafted instructions,these chatbots hold the potential to significantly augment bioinformatics education and research[3,4].However,opportunities entail both rewards and *** commentary explores the challenges of using chatbots in bioinformatics and proposes strategies to manage the associated risks while maximizing the benefits.

关键词： equipped while education

Gas microchannel plate-pixel detector for X-ray polarimetry

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Nuclear Science and Techniques 2024年第5期35卷 60-73页

作者： Huan-Bo Feng Hong-bang liu dong Wang Zi-Li Li Shu-Lin liu Qian liu Hang-Zhou Li Bin-Long Wang Yan-Jun Xie Zong-Wang Fan Hui Wang Ran Chen Di-Fan Yi Rui-Ting Ma Fei Xie Bo Peng Xiang-Ming Sun Jin Li En-Wei Liang Present Address:Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China PLAC Key Laboratory of Quark and Lepton Physics(MOE)Central China Normal UniversityWuhan 430079China School of Science Huzhou UniversityHuzhou 313000China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China School of Physical Science University of Chinese Academy of SciencesBeijing 100049China The 13th Research Institute of China Electronics Technology Group Corporation Shijiazhuang 050057China

POLAR-2 is a gamma-ray burst(GRB)polarimeter that is designed to study the polarization in GRB radiation emissions,aiming to improve our knowledge of related ***-2 is expected to utilize an on-board polarimeter that is sensitive to soft X-rays(2-10 keV),called low-energy polarization *** have developed a new soft X-ray polari-zation detector prototype based on gas microchannel plates(GMCPs)and pixel chips(Topmetal).The GMCPs have bulk resistance,which prevents charging-up effects and ensures gain stability during *** detector is composed of low outgassing materials and is gas-sealed using a laser welding technique,ensuring long-term stability.A modulation factor of 41.28%±0.64% is obtained for a 4.5 keV polarized X-ray beam.A residual modulation of 1.96%±0.58% at 5.9 keV is observed for the entire sensitive area.

关键词： X-ray polarimetry Gas microchannel plate-pixel detector Gamma-ray bursts

Experimental Study on the Effect of Increased Downstroke Duration for an FWAV with Morphing-coupled Wing Flapping Configuration

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Journal of Bionic Engineering 2024年第1期21卷 192-208页

作者： Ang Chen Bifeng Song ZhiheWang Kang liu dong Xue Xiaojun Yang School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Harbin Institute of Technology Shenzhen 518055China

This paper is based on a previously developed bio-inspired Flapping Wing Aerial Vehicle(FWAV),RoboFalcon,which can fly with a morphing-coupled flapping *** this paper,a simple flapping stroke control system based on Hall effect sensors is designed and applied,which is capable of assigning different up-and down-stroke speeds for the RoboFalcon platform to achieve an adjustable downstroke *** aerodynamic and power characteristics of the morphing-coupled flapping pattern and the conventional flapping pattern with varying downstroke ratios are measured through a wind tunnel experiment,and the corresponding aerodynamic models are developed and analyzed by the nonlinear least squares *** relatively low power consumption of the slow-downstroke mode of this vehicle is verified through outdoor flight *** results of wind tunnel experiments and flight tests indicate that increased downstroke duration can improve aerodynamic and power performance for the RoboFalcon platform.

关键词： Flapping wing aerial vehicle(FWAV) Downstroke ratio Bio-inspired design Morphing-coupled flapping

Constructing high-toughness polyimide binder with robust polarity and ion-conductive mechanisms ensuring long-term operational stability of silicon-based anodes

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Journal of Energy Chemistry 2024年第6期93卷 580-591,I0014页

作者： Yongjun Kang Nanxi dong Fangzhou liu Daolei Lin Bingxue liu Guofeng Tian Shengli Qi Dezhen Wu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China ENFI R&D Institute China ENFI Engineering CorporationBeijing 100038China China Automotive Battery Research Institute Co. Ltd.Beijing 101407China Changzhou Institute of Advanced Materials Beijing University of Chemical TechnologyChangzhou 213164JiangsuChina

Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical ***,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion ***,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high *** plentiful polar carboxyl(-COOH) groups establish robust bonding *** ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles ***,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 *** perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.

关键词： Polyimide binder High toughness Robust ionic transport Silicon-based anodes Lithium-ion batteries

Using CO_(2)and oxidants for in situ regeneration of permeable reactive barriers for leachate-contaminated groundwater

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Journal of Environmental Sciences 2024年第11期145卷 152-163页

作者： Fangming Xu Xingshen Luo Junlong Huang Yuecen dong Kaixuan Zheng Yanting liu Yanjun liu Hongtao Wang School of Environment Tsinghua UniversityBeijing 100084China School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China Zhongye Changtian International Engineering Co.Ltd. Changsha 410205China

Groundwater contamination near landfills is commonly caused by leachate leakage,and permeable reactive barriers(PRBs)are widely used for groundwater ***,the deactivation and blockage of the reactive medium in PRBs limit their long-term *** the current study,a new methodology was proposed for the in situ regeneration of PRB to remediate leachate-contaminated ***_(2)coupled with oxidants was applied for the dispersion and regeneration of the fillers;by injecting CO_(2)to disperse the fillers,the permeability of the PRB was increased and the oxidants could flow evenly into the *** results indicate that the optimumfiller proportion was zero-valent iron(ZVI)/zeolites/activated carbon(AC)=3:8:10 and the optimum oxidant proportion was COD/Na_(2)S_(2)O_(8)/H_(2)O_(2)/Fe^(2+)=1:5:6:5;the oxidation system of Fe^(2+)/H_(2)O_(2)/S_(2)O_(8)^(2−)has a high oxidation efficiency and *** average regeneration rate of zeolites was 72.71%,and the average regeneration rate of AC was 68.40%;the permeability of PRB also *** technology is effective for the remediation of landfills in China that have large contaminated areas,an uneven pollutant concentration distribution,and a long pollution *** purification mode of long-term adsorption and short-time in situ oxidation can be applied to the remediation of long-term high-concentration organically polluted groundwater,where pollution sources are difficult to cut off.

关键词： Landfill leachate Groundwater remediation PRB in situ regeneration Advanced oxidation technology

Inverting the rock mass P-wave velocity field ahead of deep buried tunnel face while borehole drilling

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International Journal of Mining Science and Technology 2024年第5期34卷 681-697页

作者： liu liu Shaojun Li Minzong Zheng dong Wang Minghao Chen Junbo Zhou Tingzhou Yan Zhenming Shi State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China China Railway Eryuan Engineering Group CO. LTD.Chengdu 610031China Department of Hydraulic and Hydropower Engineering Tsinghua UniversityBeijing 100084China Hubei Communications Planning and Design Institute CO. LTD.Wuhan 430051China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Imaging the wave velocity field surrounding a borehole while drilling is a promising and urgently needed approach for extending the exploration range of the borehole *** paper develops a drilling process detection(DPD)system consisting of a multifunctional sensor and a pilot geophone installed at the top of the drilling rod,geophones at the tunnel face,a laser rangefinder,and an onsite computer.A weighted adjoint-state first arrival travel time tomography method is used to invert the P-wave velocity field of rock mass while borehole drilling.A field experiment in the ongoing construction of a deep buried tunnel in southwestern China demonstrated the DPD system and the tomography ***-frequency analysis of typical borehole drilling detection data shows that the impact drilling source is a pulse-like seismic exploration wavelet.A velocity field of the rock mass in a triangular area defined by the borehole trajectory and geophone receiving line can be *** the borehole core and optical image validate the inverted P-wave velocity field.A numerical simulation of a checkerboard benchmark model is used to test the tomography *** rapid convergence of the misfits and consistent agreement between the inverted and observed travel times validate the P-wave velocity imaging.

关键词： Deep buried tunnel Wave velocity field Borehole drilling Tomography Rock mass

Meta-Auto-Decoder:a Meta-Learning-Based Reduced Order Model for Solving Parametric Partial Differential Equations

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1096-1130页

作者： Zhanhong Ye Xiang Huang Hongsheng liu Bin dong Beijing International Center for Mathematical Research Peking UniversityBeijing 100871China School of Computer Science and Technology University of Science and Technology of ChinaHefei 230027AnhuiChina Central Software Institute Huawei Technologies Co.LtdHangzhou 310007ZhejiangChina Center for Machine Learning Research Peking UniversityBeijing 100871China

Many important problems in science and engineering require solving the so-called parametric partial differential equations(PDEs),i.e.,PDEs with different physical parameters,boundary conditions,shapes of computational domains,*** reduced order modeling techniques accelerate the solution of the parametric PDEs by projecting them onto a linear trial manifold constructed in the ofline *** methods often need a predefined mesh as well as a series of precomputed solution snapshots,and may struggle to balance between the efficiency and accuracy due to the limitation of the linear *** the nonlinear representation of neural networks(NNs),we propose the Meta-Auto-Decoder(MAD)to construct a nonlinear trial manifold,whose best possible performance is measured theoretically by the decoder *** on the meta-learning concept,the trial manifold can be learned in a mesh-free and unsupervised way during the pre-training *** adaptation to new(possibly heterogeneous)PDE parameters is enabled by searching on this trial manifold,and optionally fine-tuning the trial manifold at the same *** numerical experiments show that the MAD method exhibits a faster convergence speed without losing the accuracy than other deep learning-based methods.

关键词： Parametric partial differential equations(PDEs) Meta-learning Reduced order modeling Neural networks(NNs) Auto-decoder