Absorbing boundary conditions are necessary in numerical simulation for reducing the artificial reflections from model boundaries. In this paper, we overview most important and typical absorbing developed throughout history. We first derive wave equations of similar methods unified forms; then, compare their performance via theoretical analyses experiments. The Higdon condition is shown to be best one among three main that based on a one-way equation. Clayton Engquist special case but has...

A new noncontacting miniature magnetic field probe for measuring the surface current distribution on high-frequency planar circuits in x-, y-, z-directions 1-20 GHz band has been designed, fabricated and tested. The probes have very small dimensions do not need any connection to operating circuit under test, therefore there is almost no perturbation of properties. This simple practical can be used assist design microwave circuits, antenna diagnostics test products industry. paper describes...

Abstract Niobium and Ta concentrations in ultrahigh‐pressure (UHP) eclogites rutile from these associated high pressure (HP) veins were used to study the behaviour of Nb–Ta during dehydration fluid‐rock interaction. Samples collected through a ∼2 km profile at Bixiling complex Dabie orogenic belt, Central‐Eastern China. All but one eclogite away (EAVs) display nearly constant Nb/Ta ratios ranging 16.1 19.2, with an average 16.9 ± 0.8 (2 SE), similar that their gabbroic protolith Yangtze...

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Three-dimensional (3-D) electric near-field probes applicable to the 0.05-20-GHz band have been developed, which can measure both magnitude and phase of microwave field inside radio-frequency (RF) circuits. The very small dimensions do not need be connected operating device-under-test (DUT), therefore, circuit properties are nearly disturbed by probe, Investigations on different circuits (e.g., antenna, meander lines, filters, power amplifiers) show that such applied only simple passive...

A new calibration technique for application to near-field probes has been developed. For this, a simple electric coaxial probe in the 0.05-20-GHz band developed, theoretically analyzed, and calibrated using known field. By finite-difference time-domain (FDTD) method, this field is analyzed determine its most sensitive segment. Taking amplitude of normal at segment as field, by defining performance factor (PF), which ratio signal amplitude. Comparing calculated results with measured results,...

This paper presents wavelet packet decomposition (WPD) and coefficient residual analysis based methods for hydraulic pump health diagnosis. A real-time diagnosis system has been created on the basis of this method. would analyse a short sequence discharge pressure signals to detect if was operating under healthy condition or not. If were with defective conditions, further be implemented identify possible cause(s) defect(s). Based results obtained from series random laboratory tests by...

The explicit finite-difference scheme is popular for solving the wave equation in field of seismic exploration due to its simplicity numerical implementation. However, maximum time step strictly restricted by Courant-Friedrichs-Lewy (CFL) stability limit, which leads a heavy computational burden presence small-scale structures and high-velocity targets. We remove CFL limit using eigenvalue perturbation, allows us use much larger beyond limit. For given that within eigenvalues update matrix...

The pursuit of strong endurance and nonflammable performances has promoted demand for solid-state batteries (SSBs). Meanwhile, the reduction electrolytes' thickness is key to improving battery performance. However, a large-scale feasible method fabricate an ultrathin solid electrolyte exhibiting high ionic conductivities still challenge. Here, we show prepare succinonitrile/polyacrylonitrile(SN/PAN)-coated Li6.4La3Zr1.4Ta0.6O12 (LLZTO) with flexibility conductivity by tape-casting. unique...

This article studies the energy-saving performances of independent metering system with pressure compensation for excavator’s manipulator. Compared to electro-hydraulic method, hydro-mechanical method is commonly applied in conventional load-sensing systems as it reacts directly and rapidly. Independent has more controllability, because meter-in meter-out orifices are decoupled. In this study, adopted designing According demand forces velocities cylinders manipulator part, control blocks...

The discontinuous-grid method can greatly reduce the storage requirements and computational costs of finite-difference (FD) modeling for large-velocity-contrast models. However, traditional methods have to use interpolation when refining wavefield in transition zones would cause apparent artifacts. We developed a new discontinuous collocated-grid scheme high-order FD modeling. refined on rotated coordinate system, where is not required again. horizontal vertical spatial derivatives be...

The symplectic integration method is popular in high-accuracy numerical simulations when discretizing temporal derivatives; however, it still suffers from time-dispersion error the interval coarse, especially for long-term and large-scale models. We employ inverse time dispersion transform (ITDT) to third-order reduce error. First, we adopt pseudospectral algorithm spatial discretization discretization. Then, apply ITDT eliminate synthetic data. As a post-processing method, can be easily...

The complex frequency shifted perfectly matched layer (CFS-PML) can improve the absorbing performance of PML for nearly grazing incident waves. However, traditional and CFS-PML are based on first-order wave equations; thus, they not suitable second-order equation. In this paper, an implementation equation is presented using auxiliary differential equations. This method free both convolution calculations third-order temporal derivatives. As unsplit CFS-PML, it reduce incidence. Numerical...

This paper reports a systematic analysis of load sensing system with hydro-mechanical pressure compensation and independent metering. In contrast to conventional spool valve controlled system, the proposed is characterised by both meter-in meter-out compensation. Quasi-static behaviour applied three distinct systems: (MIPCS), (MOPCS), (PCLSS). The energy usage equation shows that minimising pump supply only way ensure high saving efficiency; proper opening modes between orifices MIPCS MOPCS...

Three-wheeled agricultural robots possess the advantages of high flexibility, strong maneuverability, and low cost. They can adapt to various complex terrains operational environments, making them highly valuable in fields crop planting, harvesting, irrigation, more. However, horizontal stability three-wheeled robot chassis is compromised when working harsh terrain, significantly impacting overall quality safety. To address this issue, study designed a leveling system based on active...

A hydraulic drive-based self-propelled photovoltaic panel cleaning robot was developed to tackle the challenges of harsh environmental conditions, difficult roads, and incomplete dust particles on surface in power plants. The has characteristics crawler wheel drive, rear-wheel-independent turning three-point-independent suspension design, which makes it adhere walking requirements complex terrains, more flexible automatically levelling so that stability boom mechanism during can be ensured....

The independent metering system used in the combination of traditional cartridge proportional valves employs an excessive number components, which increases complexity control strategy. To address this problem, a novel based on pilot hydraulic was developed. Following pressure and flow requirements, structure valve body size two spools were designed. effect parameter change dynamic response characteristics main spool investigated by simulation. A strategy developed load force direction...

In this study, to address the issues of tooth tip operation discontinuity and jitter during autonomous excavator operation, a multi-segment mixed interpolation method utilizing different higher-order polynomials has been proposed. This approach is designed optimize trajectory under multiple constraints, resulting in smoother trajectory. Specifically, single-bucket was chosen as research object, three high-order were utilized interpolate digging discrete points. Through comparative analysis...

A simple electric coaxial field probe for application in the 0.05-20 GHz band has been developed, which can measure not only magnitude and phase of microwave distribution inside multiconductor RF circuits, but also scattering parameters at arbitrary reference planes structures be measured using this technique.

Vibration of the boom system is inevitably caused by periodic disturbances, which are induced pumping concrete. In this paper, an active control strategy constant-position commandless input shaping technique developed to suppress vibration. Based on a set independent modal equations obtained adopting approach, double-impulse with reverse direction proposed, aiming at not only suppressing vibration, but also avoiding variation equilibrium position after action. And characteristic time-lag...