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A novel method for AFRPs burrs removal:Principle of mechanochemo-induced fiber fracture

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Chinese Journal of Aeronautics 2024年第7期37卷 522-538页

作者： Jie XU Bo LI Pingfa feng Qiang w.NG feng feng Division of Advanced Manufacturing Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Changhe Aircraft Industry(Group)Co.Ltd Jingdezhen 333000China

Burrs generated during the machining of Aramid-Fiber-Reinforced Composites(AFRPs)pose a challenge for the production efficiency of aircraft and helicopter housing *** studies have generally attempted to suppress burrs by referring to delamination suppression *** contrast to stratification,burrs are remediable machining *** such,a mechanochemical method w.th burrs trimming technological strategy are implemented to effectively combat ***,w. clarify the mechanism by w.ich aramid fibers cannot be cut off using analytical and numerical *** addition,the mechanism of fiber fracture w.th Modified Polyurethane Reactive Polymer(M-PUR),and development of anti-burr devices(thermostatic adhesive sealed generator)are ***,the experimental results show.that the reduction rate in burr length is 87%-91%through the mechanochemical *** method not only opens a new.avenue to solve the burr problem of aramid fibers but also builds an interdisciplinary bridge betw.en polymer science and composite machining.

关键词： Mechanochemical method Burrs Orthogonal cutting Aramid fiber-reinforced composites Milling

Derivation of Expanded Isospectral-Nonisospectral Integrable Hierarchies via the Column-vector Loop Algebra

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 778-800页

作者： Hai-feng w.NG Yu-feng ZHANG School of Science Jimei UniversityXiamen 361021China School of Mathematics China University of Mining and TechnologyXuzhou 221116China

A scheme for generating nonisospectral integrable hierarchies is *** on the method,w. deduce a nonisospectral hierarchy of soliton equations by considering a linear spectral *** follow. that the corresponding expanded isospectral and nonisospectral integrable hierarchies are deduced based on a 6 dimensional complex linear space ■.By reducing these integrable hierarchies,w. obtain the expanded isospectral and nonisospectral derivative nonlinear Schr?dinger *** using the trace identity,the biHamiltonian structure of these tw. hierarchies are also ***,some symmetries and conserved quantities of the resulting hierarchy are discussed.

关键词： expanded isospectral-nonisospectral integrable hierarchies column-vector loop algebra bi-Hamiltonian structure symmetry

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Carbon-based materials w.th combined functions of thermal management and electromagnetic protection: Preparation, mechanisms, properties, and applications

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Nano Research 2024年第3期17卷 883-903页

作者： Junw.i Yue Yiyu feng Mengmeng Qin w.i feng School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin 300350China

The proliferation of high-pow.r,highly informationized,and highly integrated electronic devices and w.apons equipment has given rise to increasingly conspicuous issues about electromagnetic(EM)pollution and thermal *** issues,in turn,impose constraints on the performance of such equipment and jeopardize personnel *** materials,ow.ng to their diverse and modifiable structures,offer adjustable thermal and electric conductivity,rendering them highly promising for applications in fields such as thermal management and EM protection w.ich have garnered extensive research and *** pursuit of integrated device and equipment development has elevated the demand for multifunctional materials,prompting significant research into carbon-based composite materials that include both thermal management and EM protection ***,there are no relevant review. on this topic at ***,this w.rk consolidates research findings from recent years on carbon matrix composites exhibiting dual attributes of thermal management and EM *** attributes include thermally conductive electromagnetic interference(EMI)shielding materials,thermally insulating EMI shielding materials,thermally conductive EM w.ve(EMw.absorbing materials,and thermally insulating EMw.absorbing *** paper elucidates the fundamental principles underpinning thermal conduction,thermal insulation,EMw.absorbing,and EMI ***,it engages in discussions surrounding areas of contention,design strategies,and the functional properties of various material ***,the paper concludes by presenting the challenges encountered and potential research strategies about composites endow.d w.th both thermal management and EM protection functionalities,w.ile also envisaging the development of novel multifunctional EM protection materials.

关键词： carbon-based composites electromagnetic interference shielding microw.ve absorption thermal conduction thermal insulation

Design and identification of a double-acting piezoelectric-hydraulic hybrid actuator

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Chinese Journal of Aeronautics 2024年第3期37卷 456-467页

作者： Junjian ZHANG Zhihua feng Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes University of Science and Technology of ChinaHefei 230026China

Traditional single-acting piezoelectric-hydraulic hybrid actuators usually have the problem of inertial force caused by flow.pulsation of the liquid,w.ich degrades their output *** suppress or solve the associated inertial force and enhance its output capabilities,this paper proposes a new.type of double-acting piezoelectric-hydraulic hybrid actuator w.th four check valves acting as mechanical *** new.hybrid actuator w.s fabricated and its output performance w.s *** the voltage is 700 Vp-pand the bias pressure is 2 MPa,the pulsation ratesδof the new.actuator at 400 Hz,500 Hz and 600 Hz are 2.29,2.08 and 1.78,respectively,w.ileδof the single-acting hybrid actuator under the same conditions are 10.98,11.05 and ***,the liquid pulsation rate of the new.hybrid actuator is significantly reduced,w.ich is beneficial for improving the flow.uniformity and w.akening the influence of inertial force on the hybrid *** strategy ultimately leads to a maximum no-load velocity of 168.1 mm/s at 600 Hz and a maximum blocking force of 141 N at 450 Hz for the new.hybrid *** addition,this strategy has the potential to be used in other electrohydrostatic actuators to improve their performance.

关键词： Double-acting Flow.pulsation Inertial force Piezoelectric actuators Piezoelectric devices Piezoelectric hydraulic actuation Piezoelectric pump

Rational Solutions of First Order Algebraic Ordinary Differential Equations

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Journal of Systems Science & Complexity 2024年第2期37卷 567-580页

作者： feng Shuang SHEN Liyong School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjing 211816China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Let f(t,y,y')=∑ _(i=0)^(n )a_(i)(t,y)y'^(i)=0 be an irreducible first order ordinary differential equation w.th polynomial *** in 1998 proved that there exists a constant C such that every rational solution of f(t,y,y')=0 is of degree not greater than *** show.that this degree bound C depends not only on the degrees of f in t,y,y' but also on the coefficients of f view.d as the polynomial in t,y,y'.In this paper,the authors show.that if f satisfies deg(f,y)0,then the degree bound C only depends on the degrees of f in t,y,y',and furthermore w. present an explicit expression for C in terms of the degrees of f in t,y,y'.

关键词： Degree bound first order AODE height rational solution

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Turbulence Statistics of Thermo-Buoyancy Supercritical Fuel Flow.in a Regenerative Cooling Channel

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Journal of Thermal Science 2024年第1期33卷 126-137页

作者： SUN feng XIE Gongnan School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Department of Thermal Engineering Tsinghua UniversityBeijing 100084China

Active regenerative cooling w.th supercritical hydrocarbon fuel is considered as the most promising thermal protection *** existence of buoyancy force w.uld lead to strongly anisotropic flow.and thermal transport *** is closely related to the cooling performance of the *** elucidate the mechanisms of turbulent transport,the large eddy simulation(LES) w.s performed to assess turbulence statistics w.thin different turbulence *** results indicated that the buoyancy and inertial force together dominated the change of turbulent ***,the spatial thermal buoyancy effect significantly suppressed the vertical velocity *** is due to the laminar motion caused by the buoyancy force,thereby w.akening the thermal *** the statistics of velocity fluctuation,it w.s found that the buoyancy force and inertial force greatly w.aken the vertical and streamw.se velocity fluctuation,*** the statistics of thermal transport,the results pointed out that the near-w.ll heat transport characteristics need to be paid more *** thickness of the temperature mixing boundary layer led to the attenuation of vertical heat flux,w.ich inhibited vertical temperature diffusion and predisposed to extreme conditions of heat transfer *** results can enhance the academic understanding of the heat transfer mechanism of supercritical fluids,and give guidance for further applications of thermal protection.

关键词： active regenerative cooling large eddy simulation(LES) buoyancy force turbulence statistics

Oxygen vacancy boosting Fenton reaction in bone scaffold tow.rds fighting bacterial infection

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International Journal of Extreme Manufacturing 2024年第1期6卷 296-311页

作者： Cijun Shuai Xiaoxin Shi feng Yang Haifeng Tian Pei feng State Key Laboratory of Precision Manufacturing for Extreme Service Performance College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083People’s Republic of China Institute of Additive Manufacturing Jiangxi University of Science and TechnologyNanchang 330013People’s Republic of China College of Mechanical Engineering Xinjiang UniversityUrumqi 830017People’s Republic of China

Bacterial infection is a major issue after artificial bone transplantation due to the absence of antibacterial function of bone scaffold,w.ich seriously causes the transplant failure and even amputation in severe *** this study,oxygen vacancy(OV)defects Fe-doped Ti O2(OV-FeTiO2)nanoparticles w.re synthesized by nano TiO2and Fe3O4via high-energy ball milling,w.ich w.s then incorporated into polycaprolactone/polyglycolic acid(PCLGA)biodegradable polymer matrix to construct composite bone scaffold w.th good antibacterial activities by selective laser *** results indicated that OV defects w.re introduced into the core/shell-structured OV-FeTiO2nanoparticles through multiple w.lding and breaking during the high-energy ball milling,w.ich facilitated the adsorption of hydrogen peroxide(H2O2)in the bacterial infection microenvironment at the bone transplant *** accumulated H2O2could amplify the Fenton reaction efficiency to induce more hydroxyl radicals(·OH),thereby resulting in more bacterial deaths through·OH-mediated oxidative *** antibacterial strategy had more effective broad-spectrum antibacterial properties against Gram-negative Escherichia coli(***)and Gram-positive Staphylococcus aureus(***).In addition,the PCLGA/OV-FeTiO2scaffold possessed mechanical properties that match those of human cancellous bone and good biocompatibility including cell attachment,proliferation and osteogenic differentiation.

关键词： bacterial infection bone scaffold selective laser sintering Fenton reaction antibacterial properties

The noise spectral characteristics and noise reduction schemes of screw.air-source heat pump:A case study

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Building Simulation 2024年第1期17卷 53-70页

作者： Dongsheng Liu Yaohan feng Jikang Jia Pengfei Si Ya feng China Southw.st Architecture Design and Research Institute Co.Ltd. Chengdu 610041China CSCEC Green Construction Engineering Research Center Chengdu 610041China

The screw.air-source heat pump can cause incessant high noise levels during operation,w.ich might hinder adoption of this energy-efficient heat ***,acoustic measurements and comparison testing w.re performed in this *** measurements revealed that the compressor is the main noise source of the heat pump,and it show. a multipeak frequency distribution and a w.de frequency spectrum under different w.rk conditions,w.th multiple peaks at 63,250,and 1000 ***,a compressor sound insulation cover w.th broadband absorption w.s proposed,and it w.s experimentally proven that the insulation cover can reduce the maximum sound pressure level of one unit from 89.8 dBA to 79.1 ***,w. proposed several noise reduction strategies and compared their noise reduction effects using computer *** results show.d that the noise problem can be effectively improved through the rational design of the sound barrier and the layout and opening options of heat *** distance betw.en the sound barrier and heat pump and the sound attenuation due to diffraction ALa exhibit a U-shaped *** buildings of different heights,the optimal heights of noise barrier are *** 5.5-meter is the optimal height of the sound barrier for single-story *** conclusions can be applied to other building projects for heat pump noise reduction.

关键词： acoustic simulation broadband noise noise reduction air-source heat pump sound barrier

Fast nuclear-spin gates and electrons−nuclei entanglement of neutral atoms in w.ak magnetic fields

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Frontiers of physics 2024年第2期19卷 179-203页

作者： Xiao-feng Shi School of Physics Xidian UniversityXi’an 710071China

w. present a novel class of Rydberg-mediated nuclear-spin entanglement in divalent atoms w.th global laser ***,w. show.a fast nuclear-spin controlled phase gate of an arbitrary phase realizable either w.th tw. laser pulses w.en assisted by Stark shifts,or w.th three ***,w. propose to create an electrons−nuclei-entangled state,w.ich is named a super bell state(SBS)for it mimics a large Bell state incorporating three small Bell ***,w. show.a protocol to create a three-atom electrons-nuclei entangled state w.ich contains the three-body w.and Greenberger−Horne−Zeilinger(GHZ)states *** protocols possess high intrinsic fidelities,do not require single-site Rydberg addressing,and can be executed w.th large Rydberg Rabi frequencies in a w.ak,Gauss-scale magnetic *** latter tw. protocols can enable measurement-based preparation of Bell,hyperentangled,and GHZ states,and,specifically,SBS can enable quantum dense coding w.ere one can share three classical bits of information by sending one particle.

关键词： nuclear-spin qubit electrons−nuclei entanglement super Bell state Greenberger−Horne−Zeilinger state Rydberg-mediated entanglement quantum dense coding