This paper describes a highly accurate airflow volumetric flowmeter using piezoelectric micromachined ultrasonic transducers (pMUTs) arrays based on transit time. Two pieces of 10by10 multipled aluminum nitride (AlN) pMUTs at resonant frequency 980 kHz are employed to transmit and receive signals alternately. The dimension the fabricated array is about 3.5 × mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , so pMUTs-based able measure...

Abstract The influence of matrix viscosity on the mechanical behavior fiber reinforced composites was investigated in this paper. glass fabric selected as reinforcement and mixed solution composed resin, curing agent different diluent matrix. fabricated by vacuum‐assisted resin infusion (VARI). bending, impact creep properties were studied varying mass fraction 1,4‐butanediol diglycidyl ether (BDDGE) diluent, least square fitting used to fit experimental result. mathematical model for...

Axial force and deformation during drilling significantly impact the hole quality of thin-walled high-strength steel components. This study analyzed process AF1410 steel, focusing on axial force, deformation, drill cap formation, exit edge characteristics. The effects cutting speed (12.6–37.7 m/min) feed rate (0.01–0.1 mm/r) were also examined. Initially, plate undergoes elastic, outward bulging deformation. driven by elastic resistance, rises from 114.9 N to 322.1 as increases 0.025 mm/r...

This paper presents an ultrasonic driving and detection system based on a CMUT array using MEMS technology. Among them, the core component is composed of 8 × elements, each element contains 6 units. The collapse voltage single unit obtained through finite analysis 95.91 V, resonant frequency 3.16 MHz. section achieves 64-channel synchronous driving, with key parameters including adjustable excitation signal ranging from 10 kHz to 5.71 MHz, delay precision up 1 ns, duration eight pulse...

A method for monitoring the filling performance of a copper plating solution microvia metallization was examined by continuous operation in pilot bath. The carried out using simple galvanostat measurement. potential difference between two polarization curves obtained from galvanostatic measurements at different flow rates can serve as an effective indicator performance, because linear function correlate with performance. shift curve working after period be regarded occasion accumulation by-products.

The main production method of metal bipolar plate is stamping, and the size parameters flow field structure can not only change performance fuel cell, but also affect stamping quality plate. In case ensuring it necessary to study with different structures. past, there were few studies on wave forming. This paper analyzed field, formulated several sets structural dimension parameters, evaluated forming reaction zone SS304 through finite element simulation. By reducing rib height ΔH=0.075mm in...

The pore structure of marine-continental transitional shales from the Longtan Formation in Guizhou, China, was investigated using fractal dimensions calculated by FHH (Frenkel-Halsey-Hill) model based on low-temperature N2 adsorption data. Results show that overall <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <mi>D</mi> <mn>1</mn> </math> (fractal dimension under low relative pressure, id="M2"> <mi>P</mi> <mo>/</mo> <msub> <mrow> </mrow> <mn>0</mn> </msub> <mo>≤</mo>...

Exploration and development of shale gas in China have made significant breakthroughs recent years. Longmaxi shales the Xiang'exi depression are key targets for exploration middle Yangtze region. However, systematic studies on authigenic minerals their application enrichment evaluation insufficient. Therefore, this study, pyrite was selected to characterize its morphology, grain size, distribution characteristics, with hope identify favorable target depression. Herein, 44 unweathered core...

To solve the problem of coupling between torque and suspension force 12/8 bearingless switched reluctance motors (BSRMs), traditional BSRMs structure is optimized by designing a new relationship stator rotor pole arcs. This document analyzes distribution characters inductance, force, derives mathematical model BSRM, proposes decoupling control method for this motor.

The high electron mobility transistor (HEMT) structures on Si (111) substrates were fabricated with heavily Fe-doped GaN buffer layers by metalorganic chemical vapor deposition (MOCVD). heavy Fe concentrations employed for the purpose of highly insulating resulted in segregation and 3D island growth, which played role a nano-mask. situ reflectance measurements revealed transition from 2D to growth mode during GaN:Fe layer. nano-mask can effectively annihilate edge-type threading dislocations...

This paper describes a high-accuracy airflow volumetric flowmeter using piezoelectric micromachined ultrasound transducers (pMUTs) arrays based on the transit-time. Two pieces of 10by10 multipled aluminum nitride (AlN) pMUTs at resonant frequency 980 kHz are employed to transmit and receive ultrasonic signals alternately. The dimension fabricated array is about 3.5×3.5 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , so pMUTs-based...

This paper presents a fundamental control method to decrease stator vibration of the 12/8 bearingless switched reluctance motor (BSRM) at commutation point phase current. It states basis, and deduces parameters such as main winding current, suspension turn-on angle turn-off etc. In addition, torque compensation strategy is presented. Simulation results show that proposed scheme effective.

There are more and tunnel projects in the karst-developed areas Southwest China. Affected by karst caves water, tunnels often experience geological disasters such as local collapses water inrush. A simplified rock stress hardening-softening model was established based on triaxial compression test results of two kinds carbonatite to accurately analyze deformation inrush characteristics surrounding rocks after excavation. The total stress–strain curve into four linear stages: elastic stage,...

Pre-cooling the inlet air of a dry cooling tower by means spray can improve performance during periods high temperature. To study effect on thermal natural draft towers (NDDCTs), in this 3-D numerical simulations such process have been conducted using Fluent 16.2 (a two-way coupled Eulerian-Lagrangian approach). The considered NDDCT is 120 m and only half system simulated due to its structural symmetry. Three different strategies investigated at typical crosswind speed 4 m/s, which most...

Purpose In a coaxial ultrasonic flow sensor (UFS), wall thickness is vital parameter of the measurement tube, especially those with small inner diameters. The paper aims to investigate influence on transient signal characteristics in an UFS. Design/methodology/approach First, problem was researched experimentally using series tubes different thicknesses. Second, finite element method–based model time domain established validate experimental results and further discussion. Finally, plane wave...

Many radioactive pollutants will be deposited inside the nuclear power plant pipelines after long-term service, which form hot spots and increase radiation dose rate level of operators. The ultrasonic decontamination efficiency was studied through establishment dynamic test bench, under different process parameters. It has also been applied in engineering filed. results show that: Ultrasonic increases with power, maximum is up to 62.69%. main reason that mechanical effect cavitation are...

Ultrasonic decontamination technology was used to carry out tests on stainless steel pipes, observe the effect of ultrasonic pipelines, and explore influence safety pipelines containing welds. Metallic film characterize effect, metallographic microscope, micro-Vickers hardness tester, universal testing machine other equipment were matrix structure pipeline, compare strength changes, analyze pipeline. The experiment shows that with determination power, is gradually enhanced extension time....

The organic-rich shales in the northern Dongpu Depression were deposited deep and semi-deep lakes based upon evidence from geochemical characteristic rock mineral of Es3 member. results show that these rocks gradually decrease abundance deterioration organic matter types center salt lake towards edges. development high-quality member is due to stratified sedimentation a water, narrow basin water body. saline region has high TOC content, primarily type I derived low-grade aquatic organisms....

Vector form of intrinsic finite element (VFIFE) is a numerical method widely used in solid dynamics. However, it’s hard to extend the VFIFE fluid dynamics since traditional based on physical model does not explain mechanism generation and action force continuum. Therefore, under framework analytical dynamics, this paper constructs Lagrange power function with generalized velocity as variable proposes Lagrange’s equation second kind by taking extremum condition above functional. The governing...