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The oscillation wave partial discharge test has been used more and more in the detection of cable insulation defects, but the background noise interference and discharge pulse matching affect the accuracy of partial discharge location. A partial discharge localization method based on ensemble empirical mode decomposition and Hilbert marginal spectral energy is proposed to locate cable insulation defects accurately under oscillating wave voltage. Firstly, the partial discharge pulse signal is extracted by moving window threshold method. Then, the ensemble empirical mode decomposition algorithm is used to decompose the signal, and Hilbert transform is applied to each component to obtain its marginal spectral energy value. The proportion of different eigen modal function components in the original signal marginal spectral energy value is selected as the characteristic quantity, the signal similarity is calculated to match the incident pulse signal and the reflected pulse signal, and finally the partial discharge location is carried out by the time domain reflection method. The vibration wave withstand test is carried out on 35 kV cable, and the detected partial discharge signal is located and calculated. The results show that the pro-posed method can realize the location of cable insulation defect under the condition of strong Gaussian white noise, and the average location error can reach 1.15%.

Objective Methods Results Conclusion This study delves into the correlation between individual income inequality as measured by the relative deprivation index and charitable giving, while also examining urban–rural heterogeneity. Additionally, it further explores the mechanisms by which online and offline forms of social interaction operate in this context.Utilizing data from the 2014–2020 China Family Panel Studies, we employed several methodologies including Probit regression models, cross‐model average marginal effects difference testing based on bootstrap method, instrumental variable method, and the Karlson–Holm–Breen (KHB) effect decomposition method.The findings reveal that individual income inequality measured by the relative deprivation index significantly reduces charitable giving among Chinese households. The inhibitory effect of individual income inequality on social charitable giving is higher than that on charitable giving directed toward friends or colleagues. Furthermore, this impact exhibits some heterogeneity between urban and rural areas. Mechanism analysis indicates that the adverse effect of income inequality on charitable giving operates through reducing social interaction, including both online and offline forms.Our results demonstrate that income inequality has distinct adverse effects on two types of charitable giving and explain the mechanisms underlying these effects through social interaction. A pattern of the differential mode of association similar to “ripples” in Chinese society is beneficial for understanding these differentiated impacts. We believe it is necessary to improve economic inequality conditions and enhance the enthusiasm of the Chinese public for participating in charitable donations by promoting various forms of social interaction. [ABSTRACT FROM AUTHOR]

The objective of this research is to investigate the characteristics of the deformation response in adjacent subway tunnels caused by deep foundation excavation of reclaimed land. Focusing on a deep foundation excavation project situated in proximity to Line 11 of the subway in Shenzhen, this study employs theoretical analysis, numerical simulation, and on-site measurements to thoroughly investigate the deformation issues induced by the unloading of the excavation. The research results are as follows: using the energy method to calculate the uneven deformation of adjacent subway tunnels caused by the excavation can overcome the limitations of traditional algorithms, which treat the subway tunnel as a uniformly elastic foundation beam, resulting in more reasonable calculation results. Increasing the self-stiffness (EI)eq of the tunnel can effectively reduce the maximum displacement (wmax) of the tunnel, and as (EI)eq increases, its "weakening effect" on wmax gradually diminishes. Underground continuous walls can effectively control tunnel deformation, with tunnel displacement decreasing as the thickness and concrete strength of the continuous walls increase. "Long excavation" deep foundation excavations can impact the displacement and uplift range of the tunnel, with the maximum tunnel displacement showing a nonlinear decrease with increasing excavation depth. Tunnel displacement decreases as geotechnical parameters (elastic modulus E, internal friction angle φ, and cohesion C) increase, with the elastic modulus being the most sensitive parameter. The research findings can be applied to tunnel construction, maintenance, and safety evaluations, providing valuable references for similar engineering projects in the future. [ABSTRACT FROM AUTHOR]

In order to obtain the influence of the medium bubble contents on temperature rising characteristics of a hydraulic system, the working hydraulic system of a wheel loader was taken as the research object. By carrying out the comparison experiments of the hydraulic system with and without de-aeration devices on a 5-ton wheel loader, the air bubble contents and concerning temperatures were obtained. To identify the factors which have impact on temperature rising of the hydraulic system, the head chamber of boom cylinder is taken to analyze, and the temperature rising expression in a volume were deduced. By the utilization of the thermal hydraulic library, combining with mechanism and control libraries on AMESim simulation platform, the integrated simulation model of the whole system was established and verified, meanwhile, the simulation was carried out from aspects in different air contents and initial chamber temperatures. From the simulation, the prediction models of the air contents to temperature rising, and the pressures to temperature rising were predicted. Finally, the correctness of the prediction models are verified by experiment data and showing good results, which can be used to enrich and improve the calculation and evaluation methods of heat generation to any other hydraulic systems.

A new π-conjugated bridging-type dicarboxylic acid with a functional alkynyl group, 4,4′-(ethynylimino)bis[benzoic acid] (H2L), was designed and synthesized to construct a Zn(II)-based coordination compound [ZnL(dpa)]n (dpa = 4,4′-dipyridylamine). Compound 1 has two-dimensional layers with alkynyl groups protruding on each side of the layer. The introduction of the ligand dpa ensured the existence of uncoordinated nitrogen atoms. Through Hg⋯C (alkynyl group) and Hg⋯N (amino group) coordination interactions, 1 can effectively detect Hg2+ ions (Ksv = 1.34 × 104 M−1 and LOD = 3.75 × 10−4 mM) by fluorescence quenching. Meanwhile, for Fe3+, in addition to the coordination interactions between Fe3+ ions and the uncoordinated amino groups, competitive absorption was the major contributor to the fluorescence quenching of compound 1. Competitive absorption prompted the sensitive sensing of Fe3+ (Ksv = 3.09 × 104 M−1 and LOD = 1.94 × 10−4 mM) and 4-nitrophenol (Ksv = 7.46 × 104 M−1 and LOD = 4.32 × 10−4 mM). [ABSTRACT FROM AUTHOR]

Currently, most wheel-legged robots need to complete the switching of the wheel-and-leg modal in a stationary state, and the existing algorithms of statically switching the wheel-leg modal cannot meet the control requirements of multimodal switching dynamically for robots. In this paper, to achieve efficient switching of the wheel-and-leg modal for a quadruped robot, the novel transformable mechanism is designed. Then, a multimodal coordination operation control framework based on multiple algorithms is presented, incorporating the minimum foot force distribution method (algorithm No.1), the minimum joint torque distribution method (algorithm No.2), and the method of combining the single rigid body dynamic model with quadratic programming (algorithm No.3). In the process of switching wheel-leg modal dynamically, the existing algorithm No.3 is prone to produce the wrong optimal force due to the change of the whole-body rotational inertia. Therefore, an improved algorithm No.1 and algorithm No.2 are proposed, which do not consider the change in the body's inertia. The control effects of the three algorithms are compared and analyzed by simulation. The results show that algorithm No.3 can maintain a small error in attitude angle and speed tracking regardless of whether the robot is under multilegged support or omnidirectional walking compared to the other two algorithms. However, proposed algorithms No.1 and No.2 can more accurately track the target speed when the robot is walking with wheels raising and falling. Finally, a multi-algorithm combination control scheme formulated based on the above control effects has been demonstrated to be effective for the dynamic switching of the wheel-and-leg modal. [ABSTRACT FROM AUTHOR]