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Single-atom Ni-N_(4) for enhanced electrochemical sensing

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Nano Research 2024年第8期17卷 7658-7664页

作者： Zhuhui qin Bo Tang Guiru Zhang chongqing Zhu Kun Jiang Bowei Zhang Fu-Zhen Xuan Shanghai Key Laboratory of Intelligent Sensing and Detection Technology East China University of Science and TechnologyShanghai 200237China Key Laboratory of Pressure Systems and Safety of Ministry of Education East China University of Science and TechnologyShanghai 200237China school of mechanical and Power engineering East China University of Science and TechnologyShanghai 200237China Key Laboratory of Theoretical and Computational Photochemistry Ministry of EducationCollege of ChemistryBeijing Normal UniversityBeijing 100875China Interdisciplinary Research Center School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Single-atom catalysts(SACs)attract widespread attention in heterogeneous catalysis due to their maximum atomic utilization efficiency and unique physical and chemical ***,their applications in chemical sensing keep huge potential but remain ***,a Ni-N_(4)-C SAC was synthesized for the trace detection of dopamine(DA)and uric acid(UA).The Ni-N_(4)-C SAC exhibited superior sensing performance compared to the Ni *** detection range for DA and UA were 0.05–75μM and 5–90μM with detection limits of 0.027 and 0.82μM,*** functional theory(DFT)computations indicate that Ni-N_(4)-C has a lower reaction barrier during electrochemical process,indicating that the atomic Ni sites possess higher intrinsic activity than Ni ***,DA and UA show strong potential dependency on the Ni-N_(4)-C catalyst,indicating its applicability for their concurrent *** work extends the application of SACs in chemical sensing.

关键词： single-atom catalysts chemical sensing dopamine uric acid

INTELLIGENT VIRTUAL CONTROL:MEASURING INSTRUMENT FROM WHOLE TO PART

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Chinese Journal of mechanical engineering 2002年第2期15卷 131-135页

作者： qin shuren Tang BaopingCollege of mechanical engineering, chongqing university, chongqing 400044, China College of mechanical engineering Chongqing University 重庆 400044

A new concept called intelligent virtual control (IVC), which can be drivenby measuring functions, is put forward. This small 'intelligent measurement instrument unit (IMIU)',carrying with functions of instrument, consists of different types of intelligent virtualinstrument (IVI) through individual components together as building blocks and can be displayeddirectly on the computer screen. This is a new concept of measuring instrument, and also animportant breakthrough after virtual instrument (VI). Virtual control makes instrument resourcesobtain further exploitation. It brings about a fundamental change to the design and manufacturingmode. The instrument therefore, can not only be produced directly inside a PC, but the product isinvolved in the 'green product' system. So far, all the present digital instruments will grow to bereplaced by intelligent control with green characteristics.

关键词： Intelligent virtual control Measurement instrument Whole Part

ON THE AXIAL TRANSIENT RESPONSE ANALYSISOF THE SECTOR-SHAPED HYDRODYNAMIC THRUSTBEARING-ROTOR SYSTEM IN A TURBOEXPANDER

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Chinese Journal of mechanical engineering 2000年第4期13卷 318-324页

作者： Zhu qin Yi Xuemei (school of mechanical engineering，Shanghai university) 上海大学上海

A model for the non-linear axial vibrations of the hydrodynamic thrust bearing-rotor system in a turboexpander is described. The axial transient process of the system is investigated. The time-dependent form ofthe Reynolds equation is solved by a finite difference method with successive overrelaxation scheme to obtain the hydrodynamic forces of the sector-shaped thrust bearing (SSTB). Using these forces, the equation of motion is solved by the fourth-order Runge-Kutta method and the Adams method to predict the transient behaviour of the thrust bearing-rotor system (TBRS).Also,the linearized stiffness and damping coefficients of the oil film hydrodynamic SSTB are *** analyses of the axial transient response of the system under both linear and non-linear conditions are performed. The non-linearity of oil film forces can significantly contribute to the axial transient response. Conclusions obtained can be applied for evaluation of the reliability of the TBRS.

关键词： Axial transient response Thrust bearing-rotor system Turboexpander

INVESTIGATION ON THE APPLICATION OF THE BOUNDARY ELEMENT METHOD TO THE SPILL GROOVED THRUST BEARING

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Chinese Journal of mechanical engineering 2000年第2期13卷 81-89页

作者： Zhu qin Yi Xuemei (school of mechanical engineering, Shanghai university) 上海大学上海

An application of the boundary element method (BEM) is presented to calculate the behaviors of a spiral grooved thrust bearing (SGTB). The basic reason is that the SGTB has very complex boundary conditions that can hinder the effective or sufficient applications of the finite difference method (FDM) and the finite element method (FEM), despite some existing work based on the FDM and the FEM. In other to apply the BEM, the pressure control equation, i. e., Reynolds' equation, is first transformed into Laplace's and Poisson's form of the equations. Discretization of the SGTB with a set of boundary elements is thus explained in detail, which also includes the handling of boundary conditions. The Archimedean SGTB is chosen as an example of the application Of BEM, and the relationship between the behaviors and structure parameters of the bearing are found and discussed through this calculation. The obtained results lay a solid foundation for a further work of the design of the SGTB.

关键词： Pressure control equation Boundary element method Spiral grooved thrust bearing

Three Dimensional Simulation of Upset Forging by Using Variational Upper Bound Method

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Journal of Materials Science & Technology 1994年第1期10卷 15-22页

作者： Jiang qin(school of mechanical engineering, university of Bath, Claverton Down, Bath BA27AY, UK) Univ of Bath Claverton Down Bath United Kingdom

The variation principle is discussed and Rayleigh-Ritz method is proposed for construction of veloci ty field. A kinematically admissible velocity field based on polynomials was appIied to the determina tion of forging load and deformed buIge profile during upset forging of blocks. Simulation of upsetforging of rectangular blocks under various friction condjtions was performed. Comparison of the computed results with experiments and FEM shows good agreement. It is shown that this techniquecan be used for 3D simulation of metal forming process.

关键词： Simulation Three Dimensional Simulation of Upset Forging by Using Variational Upper Bound Method ASME

Nanoindentation responses of NiCoFe medium-entropy alloys from cryogenic to elevated temperatures

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Journal of Iron and Steel Research International 2024年第8期31卷 2068-2077页

作者： qin-qin Xu Kamran Karimi Amirhossein H.Naghdi Wen-yi Huo Chong Wei Stefanos Papanikolaou NOMATEN Centre of Excellence National Centre for Nuclear ResearchOtwock 05-400MazowszePoland College of mechanical and Electrical engineering Nanjing Forestry UniversityNanjing 210037JiangsuChina Science and Technology on Thermo Structural Composite Materials Laboratory Northwestern Polytechnical UniversityXi'an 710072ShaanxiChina school of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072ShaanxiChina

NiCoFe alloy,a medium-entropy alloy,shows potential for applications in extreme ***,there is a theoretical barrier concerning the unclear understanding of its high-temperature dislocation motion *** load response exhibits distinct signatures relevant to thermal activation,most notably a decrease in critical force(i.e,softening)from cryogenic to elevated temperatures,e.g.,from 200 to 1000 *** onset of plasticity is characterized by the nucleation of stacking faults and prismatic loops at low temperatures,whereas the surface nucleation of Shockley partial dislocations dominates plasticity at elevated *** show that thermal effects lead to non-uniform atom pile-ups and control the rate of phase transformation with increasing indentation *** findings in this work extend the understanding of the mechanical response of NiCoFe alloys under indentation at different temperatures,shedding light on the underlying dislocation motion mechanisms and surface deformation *** observed transformation-induced plasticity mechanism has implications for the properties of medium-entropy alloys and their potential applications in extreme environments.

关键词： Orientation Dislocations mechanical behaviors Phase transition

Reynolds-number scaling analysis on lift generation of a flapping and passive rotating wing with an inhomogeneous mass distribution

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Chinese Journal of Aeronautics 2024年第2期37卷 259-269页

作者： Suyang qin Haotian HANG Yang XIANG Hong LIU J.C.Wu center for aerodynamics school of aeronautics and astronauticsshanghai jiao tong universityshanghai 200240china

Insects usually fly by passively rotating wings,which has been applied to the design of flapping-wing Micro-Air Vehicles(MAVs)to reduce mechanical *** this paper,a robotic passive rotating-wing model is designed to investigate wing kinematics and lift generation,which are measured by a high-speed camera and a force transducer,*** addition,flow fields are measured using the Particle Image Velocimetry(PIV).Experimental results demonstrate that passive rotating motion has a coordinative relationship with actively stroking *** the stroke amplitude or frequency increases,the rotating amplitude is *** characterize the active stroking motion,a driving Reynolds number Redrivingis defined,which varies from 68 to 366 in this *** the gravity center of the wing towards trailing ed ge induces the increase of additional torque M,which decreases the wing rotating amplitude and promotes the advance of wing *** find that the timing of wing rotation is gradually delayed and the mean lift coefficient C^(-)_(L)monotonously decreases as *** increasing the additional torque M,C^(-)_(L)is slightly improved and approaches to the lift coefficient of a real fruit fly at driving Re approximately equal to *** instantaneous lifts combined with the vortical structures further demonstrate that the lift generation associated with wing rotation is mainly attributed to the growth of the LeadingEdge Vortex(LEV)and the passive wake capture *** wake capture is influenced by LEV,reversal stroke motion and wing additional torque together,which can only maintain the lift at a high level for a considerable *** high-lift generation mechanisms of flapping and passive rotating flight could shed light on the simplified design of MAVs and the improvement of their aerodynamic performance.

关键词： Flapping flight Unsteady lift Passive rotation Vortex flow Leading-edge vortex

Random Forest-Based Fatigue Reliability-Based Design Optimization for Aeroengine Structures

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Computer Modeling in engineering & Sciences 2024年第7期140卷 665-684页

作者： Xue-qin Li Lu-Kai Song school of Energy and Power engineering Beihang UniversityBeijing100191China Department of mechanical engineering The Hong Kong Polytechnic UniversityKowloonHong Kong999077China Research Institute of Aero-Engine Beihang UniversityBeijing100191China

Fatigue reliability-based design optimization of aeroengine structures involves multiple repeated calculations of reliability degree and large-scale calls of implicit high-nonlinearity limit state function,leading to the traditional direct Monte Claro and surrogate methods prone to unacceptable computing efficiency and *** this case,by fusing the random subspace strategy and weight allocation technology into bagging ensemble theory,a random forest(RF)model is presented to enhance the computing efficiency of reliability degree;moreover,by embedding the RF model into multilevel optimization model,an efficient RF-assisted fatigue reliability-based design optimization framework is *** the low-cycle fatigue reliability-based design optimization of aeroengine turbine disc as a case,the effectiveness of the presented framework is *** reliabilitybased design optimization results exhibit that the proposed framework holds high computing accuracy and computing *** current efforts shed a light on the theory/method development of reliability-based design optimization of complex engineering structures.

关键词： Random forest reliability-based design optimization ensemble learning machine learning

RESEARCH OF WAVELET TRANSFORM INSTRUMENT SYSTEM FOR SIGNAL ANALYSIS

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Chinese Journal of mechanical engineering 2000年第2期13卷 114-121页

作者： qin shuren Chen Zhikui Tang Baoping Yang Changqi Xu Mingtao He Hui (Test Center, chongqing university) 重庆大学重庆

After brief describing the Principle of wavelet transform (WT) of signals, a new signals analysis system based on wavelet transform is introduced. The design and development of the instryment of wavelet transform are described. A number of practical uses of this system demonstrate that wavelet transform system is specially functional in identifying and processing impulse, singular and non-smooth signals, so that it should be evaluated the most advanced signal analyzing system.

关键词： Wavelet transform Signal analysis Instrument