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Preparation of CeO_(2) abrasives by reducing atmosphere-assisted molten salt method for enhancing their chemical mechanical polishing performance on SiO_(2)substrates

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Journal of Rare Earths 2023年第10期41卷 1627-1635,I0006页

作者： Ning Xu Jiahui Ma qi Liu Yuxin Luo Yongping Pu School of Material Science and Engineering Shaanxi University of Science&TechnologyXi'an710021China Shaanxi Key Laboratory of Green Preparation and functionalization for Inorganic Materials Xi'an710021China

Ce^(3+)as the active site on the CeO_(2)abrasive surface is the key to enhancing the material removal rate(MRR).The CeO_(2)abrasives with high chemical activity were prepared by the molten salt method under a reducing *** crystal structure and morphology of CeO_(2)abrasive s were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),ultraviolet—visible diffuse reflectance spectroscopy(UV-Vis DRS),and X-ray photoelectron spectroscopy(XPS).The CeO_(2)abrasives were obtained under different atmospheres(Air,Ar,and Ar/H_(2)).With the enhancement of the reducing atmosphere,the morphology of the abrasives transforms from spherical to octahedral,while more oxygen vacancies and Ce^(3+)are generated on the surface of CeO_(2)*** CMP experiments show that the MRRs of the CeO_(2)-Air,CeO_(2)-Ar,and CeO_(2)-Ar/H_(2)abrasives on SiO_(2)substrates are 337.60,578.74,and 691.28 nm/min,***,as confirmed by atomic force microscopy(AFM),the substrate surfaces exhibit low roughness(20.5 nm)after being polished using all of the prepared ***,the MRR of CeO_(2)-Ar/H_(2)abrasives is increased by 104.76%compared with CeO_(2)-air *** improved CMP performance is attributed to the increased Ce^(3+)concentration and the octahedral morphology of the abrasives enhancing the chemical reaction and mechanical removal at the abrasive-substrate interface.

关键词： CeO_(2) Chemical mechanical polishing(CMP) Reducing atmosphere Material removal rate(MRR) Molten salt method Rare earths

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Flexible polydimethylsiloxane pressure sensor with micro-pyramid structures and embedded silver nanowires:A novel application in urinary flow measurement

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Nanotechnology and Precision Engineering 2024年第3期7卷 1-12页

作者： Ben-Song Wang Ang Gao Song-Wei Huang qi-Hong Ning Cheng Zhou qi-Xiang Song Da-XiangCui School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Urology Renji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200240China

Flexible pressure sensors are lightweight and highly sensitive,making them suitable for use in small portable devices to achieve precise measurements of tiny *** article introduces a low-cost and easy-fabrication strategy for piezoresistive flexible pressure *** embedding silver nanowires into a polydimethylsiloxane layer with micro-pyramids on its surface,a flexible pressure sensor is created that can detect low pressure (17.3 Pa) with fast response (furthermore,the pressure sensor exhibits a sensitive and stable response to a small amount of water flowing on its *** this basis,the flexible pressure sensor is innovatively combined with a micro-rotor to fabricate a novel urinary flow-rate meter (uroflowmeter),and results from a simulated human urination experiment show that the uroflowmeter accurately captured all the essential shape characteristics that were present in the pump-simulated urination *** ahead,this research provides a new reference for using flexible pressure sensors in urinary flow-rate monitoring.

关键词： Flexible pressure sensor Silver nanowires Portable device Uroﬂowmeter Healthcare

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Stability of a Variable Coefficient Star-Shaped Network with Distributed Delay

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Journal of Systems Science & Complexity 2022年第6期35卷 2077-2106页

作者： ZHANG Hai-E XU Gen-qi CHEN Hao LI Min School of Mathematics Tianjin UniversityTianjin 300350China Department of Basic Science Tangshan UniversityTangshan 063000China School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

The paper deals with the exponential stability problem of a variable coefficient star-shaped network,whose strings are coupled at a common end in a star-shaped configuration and the common connection of all strings can be *** kinds of media materials with a component of viscous and another simply elastic are distributed on each *** suitable hypothesis on the coefficient functionsμj(x)of damping terms and the kernelsηj(s)of distributed delay terms,the well-posedness of the system is obtained by means of resolvent family *** addition,the allocation proportion of the two parts and the property of the material character functions are discussed when the starshaped network is exponentially ***,the sufficient condition of exponential stability is *** simulations are also included to verify the main results.

关键词： Allocation proportion elastic and viscous exponential stability resolvent family starshaped network

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Toward better understanding vacuum ultraviolet-iodide induced photolysis via hydrogen peroxide formation,iodine species change,and difluoroacetic acid degradation

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Frontiers of Environmental Science & Engineering 2022年第5期16卷 3-12页

作者： Yang Yang qi Zhang Baiyang Chen Liangchen Long Guan Zhang State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

Recently,a photochemical process induced by ultraviolet(UV),vacuum UV(VUV),and iodide(I–)has gained attention for its robust potential for contaminant ***,the mechanisms behind this process remain unclear because both oxidizing and reducing reactants are likely *** better understand this process,this study examined the evolutions of hydrogen peroxide(H_(2)O_(2))and iodine species(i.e.,iodide,iodate,and triiodide)during the UV/VUV/I–process under varying pH and dissolved oxygen(DO)*** show that increasing DO in water enhanced H2O2 and iodate production,suggesting that high DO favors the formation of oxidizing *** contrast,increasing pH(from 6.0 to 11.0)resulted in lower H_(2)O_(2) and iodate formation,indicating that there was a decrease of oxidative capacity for the UV/VUV/I–*** addition,difluoroacetic acid(DFAA)was used as an exemplar contaminant to verify above *** its degradation kinetics did not follow a constant trend as pH increases,the relative importance of mineralization appeared declining,suggesting that there was a redox transition from an oxidizing environment to a reducing environment as pH *** treatability of the UV/VUV/I–process was stronger than UV/VUV under pH of 11.0,while UV/VUV process presented a better performance at pH lower than 11.0.

关键词： Vacuum ultraviolet Hydrogen peroxide Iodate Hydroxyl radical Redox transition

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Recent Progress on Metal–Organic Framework and Its Derivatives as Novel Fire Retardants to Polymeric Materials

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Nano-Micro Letters 2020年第12期12卷 173-193页

作者： Jing Zhang Zhi Li Xiao‑Lin qi De‑Yi Wang IMDEA Materials Institute C/Eric Kandel 228906 GetafeMadridSpain Universidad Politécnica de Madrid E.T.S.de Ingenieros de Caminos28040 MadridSpain China‑Spain Collaborative Research Center for Advanced Materials School of Materials Science and EngineeringChongqing Jiaotong UniversityChongqing 400074People’s Republic of China

High flammability of polymers has become a major issue which has restricted its ***,highly crystalline materials and metal–organic frameworks(MOFs),which consisted of metal ions and organic linkers,have been intensively employed as novel fire retardants(FRs)for a variety of polymers(MOF/polymer).The MOFs possessed abundant transition metal species,fire-retardant elements and potential carbon source accompanied with the facile tuning of the structure and property,making MOF,its derivatives and MOF hybrids promising for fire retardancy *** recent progress and strategies to prepare MOF-based FRs are emphasized and *** fire retardancy mechanisms of MOF/polymer composites are explained,which may guide the future design for efficient MOF-based ***,the challenges and prospects related to different MOFbased FRs are also discussed and aim to provide a fast and holistic overview,which is beneficial for researchers to quickly get up to speed with the latest development in this field.

关键词： Metal–organic frameworks Hybrids Polymers Composites Fire retardancy

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Numerical study on the effects of a semi-free and non-uniform flexible filament in different vortex streets

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Acta Mechanica Sinica 2021年第6期37卷 929-937,I0001页

作者： Liang Liu Guoyi He Xinyi He qi Wang Longsheng Chen School of Aircraft Engineering Nanchang Hangkong UniversityNanchang330063China

The variable flexibility of a fish body is believed to play a significant role in improving swimming *** explore the effect of non-uniform flexibility on the motion performance of fish under biologically relevant conditions,we set up three different flexible distribution modes for a semi-free filament and compared the motion performance of different flexible distribution modes through numerical *** filament is located in the wake of the front flapping foil;it can swing adaptively in the lateral direction according to the flow situation of the surrounding fluid and finally reach a stable *** results show that the motion state of the filament will alter with a change in the flexibility of the filament,from moving in the vortex street to moving on the side of the vortex *** the Bénard-von Kármán(BvK)vortex streets,the drag coefficient of the filament increases as the flexibility of the filament increases,and the value of the drag coefficient is at a minimum when the flexibility of the filament increases linearly along the length of the *** investigation indicates that at 85%–90%of the filament length(starting from the leading edge),the flexibility of the filament begins to increase significantly,and the filament can obtain its best propulsion *** results of this work provide new insights into the role of non-uniform flexibility during the process of fish movement and provide a valuable reference for the design of bionic underwater vehicles.

关键词： Immersed boundary method Non-uniform flexible Swimming performance Semi-free flexible filament

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Precision wire electrochemical machining of thick structures in powder superalloy René88DT using a partially insulated tube electrode

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Advances in Manufacturing 2023年第4期11卷 618-635页

作者： Cheng Tang Zhao Han Zhong-qi Zhou Xiao-Long Fang Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing210016People’s Republic of China

Wire electrochemical machining(WECM)is a potential method for manufacturing macrostructures from difficult-to-cut materials,such as turbine slots,with good surface integrity and low *** this study,a novel tube electrode with array holes in the front and insulation in the back was applied using WECM to improve the machining precision and ***,assisted by an immersion electrolyte and axial flushing,the electrolyte-deficient gap was supplemented to achieve the cutting of a very thick *** simulation results indicated that this method could effectively reduce the machining gap and improve the uniformity of the electric-and flow-field *** verified that when the uninsulated range(machining angle)was reduced from 360°to 90°,the side machining gap was reduced from 462.5µm to 175µ***,using optimized machining parameters,array slits with gaps as small as(175±10)μm were machined on a powder superalloy René88DT sample with a thickness of 10 mm at a feed rate of 16µm/*** feasibility of fabricating complex profiles using this method was verified using a self-designed servo device.

关键词： Wire electrochemical machining(WECM) Tube electrode Partial insulation Machining angle Electrolyte flushing Surface quality

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Optical properties and irradiation resistance of novel high-entropy oxide glasses La_(2)O_(3)-TiO_(2)-Nb_(2)O_(5)-WO_(3)-M_(2)O_(3)(M=B/Ga/In)

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Journal of Rare Earths 2023年第4期41卷 507-515页

作者： Xiaoyan Zhang Jinrong Zhang Chenhe Zhou Li Li Xiwei qi School of Materials Science and Engineering Northeastern UniversityShenyang 110819China School of Resources and Materials Northeastern University at QinhuangdaoQinhuanghao 066004China Key Laboratory of Dielectric and Electrolyte functional Material Hebei ProvinceQinhuanghao 066004China College of Metallurgy and Energy North China of Science and TechnologyTangshan 063210China

A new class of high-entropy oxide glasses 20LaO_(3/2)-20TiO_(2)-20NbO_(5/2)-20WO_(3)-20MO_(3/2)(M=B/Ga/In)were designed and successfully fabricated by aerodynamic containerless *** results show that one can control the properties and increase the functionality of glass by changing the type of *** Vicker's hardness reaches the highest value of 6.45 GPa for glass M=*** best thermal stability and the glass forming ability,measured using the glass-transition temperature T_(g) and the temperature gap ΔT respectively,are found in glass M=In,with T_(g)=740℃ and ΔT=72℃.The optical properties show that the as-prepared glasses exhibit good transparency and high refractive *** for glass M=In,its transmittance reaches almost 78% from visible to IR region,and the value is nearly unchanged after electron beam irradiation,indicating good irradiation resistance of this high-entropy oxide ***,the glass M=In has the highest refractive index(n_(d)=2.46) and low wavelength dispersion(v_(d)=45.6).These results demonstrate that the conceptual design of high-entropy materials is adaptable to high performance oxide glasses,which should be promising host materials for optical applications such as smart phones with digital cameras and endoscopes.

关键词： High entropy oxide glass Containerless process High refractive index High transmittance Lower wavelength dispersion Rare earths

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Optimal design of a novel cylindrical sandwich panel with double arrow auxetic core under air blast loading

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Defence Technology（防务技术） 2020年第3期16卷 617-626页

作者： Xu-ke Lan qi Huang Tong Zhou Shun-shan Feng State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

The increasing threat of explosions on the battle field and the terrorist action requires the development of more effective blast resistance materials and *** structure can support the external loads effectively by virtue of their spatial *** review of the excellent energy absorption property of auxetic structure,employing auxetic structure as core material in curved sandwich shows the potential to improve the protection *** this study,a novel cylindrical sandwich panel with double arrow auxetic(DAA) core was designed and the numerical model was built by *** to the complexity of the structure,systematic parameter study and optimal design are *** cases of optimal design were considered,case1 focuses on reducing the deflection and mass of the structure,while case2 focuses on reducing the deflection and increasing the energy absorption per unit *** study and optimal design were conducted based on Latin Hypercube Sampling(LHD)method,artificial neural networks(ANN) metamodel and the nondominated sorting genetic algorithm(NSGA-Ⅱ).The Pareto front was obtained and the cylindrical DAA structure performed much better than its equal solid panel in both blast resistance and energy absorption *** results can be used as a reference for different applications.

关键词： Auxetic structure Blast response Finite element analysis(FEA) Optimal design

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Research on consensus of multi-agent systems with and without input saturation constraints

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Journal of Systems Engineering and Electronics 2021年第4期32卷 947-955页

作者： qi Duo HU junhua LIANG Xiaolong ZHANG Jiaqiang ZHANG Zhihao Air Traffic Control and Navigation College Air Force Engineering UniversityXi’an 710051China Shaanxi Province Lab.of Meta-Synthesis for Electronic&Information System Xi’an 710051China Aeronautical Engineering College Air Force Engineering UniversityXi’an 710038China

In recent years,with the continuous development of multi-agent technology represented by unmanned aerial vehicle(UAV)swarm,consensus control has become a hot spot in academic *** this paper,we put forward a discrete-time consensus protocol and obtain the necessary and sufficient conditions for the second-order consensus of the second-order multi-agent system with a fixed structure under the condition of no saturation *** theoretical derivation verifies that the two eigenvalues of the Laplacian of the communication network matrix and the sampling period have an important effect on achieving *** we construct and verify sufficient conditions to achieve consensus under the condition of input saturation *** results show that consensus can be achieved if velocity,position gain,and sampling period satisfy a set of inequalities related to the eigenvalues of the Laplacian ***,the accuracy and validity of the theoretical results are proved by numerical simulations.

关键词： multi-agent system consensus control input constraint distributed control

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