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3D coarse-grained DPM simulation of the MIP reaction-regeneration loop

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Particuology 2024年第6期89卷 57-66页

作者： Yanhao Ye shuai zhang Ji Xu Wei Ge State Key Laboratory of Mesoscience and Engineering(formerly State Key Laboratory of Multiphase Complex Systems) Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China

The reactor-regenerator loop is the core facility of the maximizing iso-paraffin(MIP)*** the discrete particle method(DPM)simulation can provide detailed information at the particle scale,it has been unable to simulate such a complex loop system due to limitations of coarse-grained(CG)models,computing software,and *** this study,a newly proposed soft-shell CG-DPM model with a CG ratio of up to 800 is used to simulate a 3.5 Mt/a industrial-scale MIP reactor-regenerator *** solid fraction distribution obtained is found to agree well with in-situ *** properties including the distribution of solid fraction,gas and solid velocity,standard derivation of solid fraction with time,temporal distribution of the flow field,and particle residence time distribution are measured in the simulation,which are meaningful to better design and operate such systems in the future.

关键词： Discrete particle method Coarse-grain Maximizing iso-paraffins Full-loop Reaction-regeneration system

Research on blade tip clearance cavitation and turbulent kinetic energy characteristics of axial flow pump based on the partially-averaged Navier-Stokes model

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Journal of Hydrodynamics 2024年第1期36卷 184-201页

作者： Xiao-qi Jia shuai-kang zhang Zu-chao Zhu Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou310018China

To reveal the cavitation forms of tip leakage vortex(TLV)of the axial flow pump and the flow mechanism of the flow field,this research adopts the partially-averaged Navier-Stokes(PANS)model to simulate the cavitation values of an axial flow pump,followed by experimental *** experimental result shows that compared with the shear stress transport(SST)k-ωmodel,the PANS model significantly reduces the eddy viscosity of the flow field to make the vortex structure clearer and allow the turbulence scale to be more robustly *** cavitation area within the axial flow pump mainly comprises of TLV cavitation,clearance cavitation and tip leakage flows combined effect of triangular cloud cavitation *** formation and development of cavitation are accompanied by the formation and evolution of vortex,and variations in vortex structure also generate and promote the development of *** addition,an in-depth analysis of the relationship between the turbulent kinetic energy(TKE)transport equation and cavitation patterns was also conducted,finding that the regions with relatively high TKE are mainly distributed around gas/liquid boundaries with serious cavitation and evident gas-liquid *** phenomenon is mainly attributed to the combined effect of the pressure action term,stress diffusion term and TKE production term.

关键词： Cavitation axial flow pump tip leakage vortex(TLV) partially-averaged Navier-Stokes(PANS)model turbulent kinetic energy(TKE)

Interface Engineering of Titanium Nitride Nanotube Composites for Excellent Microwave Absorption at Elevated Temperature

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Nano-Micro Letters 2024年第9期16卷 147-160页

作者： Cuiping Li Dan Li shuai zhang Long Ma Lei zhang Jingwei zhang Chunhong Gong College of Chemistry and Molecular Sciences Henan UniversityKaifeng 475004People’s Republic of China National and Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Henan UniversityKaifeng 475004People’s Republic of China

Currently,the microwave absorbers usually suffer dreadful electromagnetic wave absorption(EMWA)performance damping at elevated temperature due to impedance mismatching induced by increased conduction ***,the development of high-performance EMWA materials with good impedance matching and strong loss ability in wide temperature spectrum has emerged as a top ***,due to the high melting point,good electrical conductivity,excellent environmental stability,EM coupling effect,and abundant interfaces of titanium nitride(TiN)nanotubes,they were designed based on the controlling kinetic diffusion procedure and Ostwald ripening *** from boosted heterogeneous interfaces between TiN nanotubes and polydimethylsiloxane(PDMS),enhanced polarization loss relaxations were created,which could not only improve the depletion efficiency of EMWA,but also contribute to the optimized impedance matching at elevated ***,the TiN nanotubes/PDMS composite showed excellent EMWA performances at varied temperature(298-573 K),while achieved an effective absorption bandwidth(EAB)value of 3.23 GHz and a minimum reflection loss(RLmin)value of−44.15 dB at 423 *** study not only clarifies the relationship between dielectric loss capacity(conduction loss and polarization loss)and temperature,but also breaks new ground for EM absorbers in wide temperature spectrum based on interface engineering.

关键词： TiN nanotubes Interface engineering Polarization loss Impedance matching Electromagnetic wave absorption performance

Photocatalytic transformation of selected biomass derivatives to value added chemicals and hydrogen fuel

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Chinese Chemical Letters 2024年第3期35卷 19-26页

作者： Xiangjun Liu shuai zhang Miao Wang Junqi Wang School of Human Settlements and Civil Engineering Xi'an Jiaotong UniversityXi'an 710049China

Biomass is the most bountiful renewable carbon resource on *** transformation is a promising method to utilize biomass to obtain high-value-added chemicals and it has more obvious advantages compared with thermochemical and biological processes due to the milder operational conditions,fewer reagents and *** material is one of the most common kinds of heterogeneous biomass photocatalysts,which has the advantages of high selectivity,stable catalytic performance,long activation time,and low *** this paper,the significant research progress on the photocatalytic transformation of biomass with semiconductor materials to produce high-value-added chemicals is reviewed,and the three most typical semiconductor photocatalysts(TiO_(2),Cd S,and g-C_(3)N_(4))are *** photocatalytic mechanism and photocatalytic system optimization including structural modification,metal co-catalyst loading,and introduction of heterojunction are ***,the main problems,the development direction and trend of semiconductor materials in photocatalytic transformations of biomass in the future are prospected,which provide guidance and inspiration for the further development of semiconductor photocatalysts and make contributions to the progress in efficient utilization of biomass.

关键词： Photocatalytic transformation Biomass Semiconductor material H_(2) High value-added chemical

Vibration Control of the Rail Grinding Vehicle with Abrasive Belt Based on Structural Optimization and Lightweight Design

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 311-337页

作者： Wengang Fan shuai zhang Zhiwei Wu Yi Liu Jiangnan Yu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control TechnologyMinistry of EducationBeijing 100044China China Railway Materials Operation and Maintenance Technology Co. LtdBeijing 100036China

As a new grinding and maintenance technology,rail belt grinding shows significant advantages in many applications The dynamic characteristics of the rail belt grinding vehicle largely determines its grinding performance and service *** order to explore the vibration control method of the rail grinding vehicle with abrasive belt,the vibration response changes in structural optimization and lightweight design are respectively analyzed through transient response and random vibration simulations in this ***,the transient response simulation analysis of the rail grinding vehicle with abrasive belt is carried out under operating conditions and non-operating ***,the vibration control of the grinding vehicle is implemented by setting vibration isolation elements,optimizing the structure,and increasing ***,in order to further explore the dynamic characteristics of the rail grinding vehicle,the random vibration simulation analysis of the grinding vehicle is carried out under the condition of the horizontal irregularity of the American AAR6 ***,by replacing the Q235 steel frame material with 7075 aluminum alloy and LA43M magnesium alloy,both vibration control and lightweight design can be achieved *** results of transient dynamic response analysis show that the acceleration of most positions in the two working conditions exceeds the standard value in GB/T 17426-1998 *** optimizing the structure of the grinding vehicle in three ways,the average vibration acceleration of the whole car is reduced by about 55.1%from 15.6 m/s^(2) to 7.0 m/s^(2).The results of random vibration analysis show that the grinding vehicle with Q235 steel frame does not meet the safety conditions of 3σ.By changing frame material,the maximum vibration stress of the vehicle can be reduced from 240.7 MPa to 160.0 MPa and the weight of the grinding vehicle is reduced by about 21.7%from 1500 kg to 1175 *** modal analysis results indic

关键词： Vibration control Dynamic characteristics Structural optimization Lightweight design Modal analysis

Flexible regulation engineering of titanium nitride nanofibrous membranes for efficient electromagnetic microwave absorption in wide temperature spectrum

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Nano Research 2024年第3期17卷 1666-1675页

作者： Cuiping Li Lu zhang shuai zhang Qiqi Yu Dan Li Lei zhang Chunhong Gong Jingwei zhang Institute of Functional Polymer Composites College of Chemistry and Molecular SciencesHenan UniversityKaifeng 475004China National&Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Henan UniversityKaifeng 475004China

Simultaneous development of well impedance matching and strong loss capability has become a mainstream method for achieving outstanding electromagnetic microwave absorption(EMWA)performances over wide temperature ***,it is difficult to pursue both due to the mutual restraint of relationship between impedance matching and loss capability about ***,we propose a flexible regulation engineering of titanium nitride(TiN)nanofibrous membranes(NMs,TNMs),which could be distributed uniformly in the polydimethylsiloxane(PDMS)matrix and contributed to the formation of abundant local conductive networks,generating the local conductive loss and enhancing the loss ability of ***,when the TNMs are used as functional units and dispersed in the matrix,the corresponding composites exhibit an outstanding anti-reflection effect on *** hoped,under the precondition of good impedance matching,local conductive loss and polarization loss together improve the loss capacity at room temperature,and polarization loss can compensate the local conductive loss to acquire effective dielectric response at elevated *** from the reasonably synergistic loss ability caused by flexible regulation engineering,the corresponding composites exhibit the perfect EMWA performances in a wide temperature range from 298 to 573 *** work not only elaborates the ponderable insights of independent membrane in the composition-structure-function connection,but also provides a feasible tactic for resolving coexistence of well impedance matching and strong loss capability issues in wide temperature spectrum.

关键词： flexible titanium nitride nanofibrous membranes local conductive loss dielectric loss electromagnetic microwave absorption wide temperature spectrum

ATSSC:An Attack Tolerant System in Serverless Computing

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China Communications 2024年第6期21卷 192-205页

作者： zhang shuai Guo Yunfei Hu Hongchao Liu Wenyan Wang Yawen Information Engineering University Zhengzhou 450002China

Serverless computing is a promising paradigm in cloud computing that greatly simplifies cloud *** serverless computing,developers only provide function code to serverless platform,and these functions are invoked by its driven ***,security threats in serverless computing such as vulnerability-based security threats have become the pain point hindering its wide *** ideas in proactive defense such as redundancy,diversity and dynamic provide promising approaches to protect against ***,these security technologies are mostly applied to serverless platform based on“stacked”mode,as they are designed independent with serverless *** lack of security consideration in the initial design makes it especially challenging to achieve the all life cycle protection for serverless application with limited *** this paper,we present ATSSC,a proactive defense enabled attack tolerant serverless *** integrates the characteristic of redundancy,diversity and dynamic into serverless seamless to achieve high-level security and ***,ATSSC constructs multiple diverse function replicas to process the driven events and performs cross-validation to verify the *** order to create diverse function replicas,both software diversity and environment diversity are ***,a dynamic function refresh strategy is proposed to keep the clean state of serverless *** implement ATSSC based on Kubernetes and *** and experimental results demonstrate that ATSSC can effectively protect serverless computing against cyberattacks with acceptable costs.

关键词： active defense attack tolerant cloud computing security serverless computing

Design and calibration of spoke piezoelectric six-dimensional force/torque sensor for space manipulator

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Chinese Journal of Aeronautics 2024年第1期37卷 218-235页

作者： Yingjun LI Guicong WANG shuai zhang Yuanqin ZHOU Hongyu LI Zhenguang QI School of Mechanical Engineering University of JinanJinan 250022China

The large manipulator outside the space cabin is a multi-degree of freedom actuator for space *** order to realize the automatic control and flexible operation of the space manipulator,a novel spoke structure piezoelectric six-dimensional force/torque sensor with redundancy ability,high stiffness and good decoupling performance is innovatively *** on the deformation coordination relationship,the redundancy measurement mechanism is *** mathematical models of the sensor with and without branch fault are established *** finite element model is established to verify the feasibility of structure and redundancy measuring principle of the *** on the theoretical analysis and simulation analysis,the prototype of the sensor is *** and dynamic calibration experiments are carried *** actual output voltage signal of the six-dimensional force/torque sensor is collected to establish the equation between the standard input applied load and the actual output voltage *** on ant colony optimized BP algorithm,performance indexes of the sensor with and without branch fault are analyzed *** experimental results show that the spoke piezoelectric sixdimensional force/torque sensor with the eight-point support structure has good accuracy and ***,it has strong decoupling characteristic that can effectively shield the coupling between *** nonlinear errors and maximum interference errors of decoupled data with and without branch faults are less than 1% and 2%,*** natural frequency of the sixdimensional force sensor can reach 2856.45 Hz and has good dynamic *** research content lays a theoretical and experimental foundation for the design,development and application of the new six-dimensional force/torque sensors with ***,it will significantly improve the research level in this field,and provide a strong guarantee for the smoot

关键词： Decoupling algorithm Piezoelectric Redundancy Six-dimensional force/torque sensor Space manipulator

Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe)octahedrons

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Chinese Journal of Chemical Engineering 2024年第2期66卷 298-309页

作者： Hao Yuan Xinhai Sun shuai zhang Weilong Shi Feng Guo School of Material Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212003China

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic ***,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)*** electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of ***,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry *** research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.

关键词： Carbon dots MIL-101(Fe) Photocatalytic Persulfate activation Tetracycline degradation