As a proven and highly efficient processing technique, electrochemical machining (ECM) is used for difficult-to-cut Ni-based superalloys (such as Hastelloy® X [HX] fabricated via selective laser melting [SLM]) with complex shapes. However, the metallic surface susceptible to passive film formation reduce dissolution rate of HX under low current density conditions during ECM process. This study focused on optimising microstructures SLM-fabricated heat treatment enhance its behaviour. The...

Aiming at the problems of target detection models in traffic scenarios including a large number parameters, heavy computational burden, and high application cost, this paper introduces an enhanced lightweight real-time algorithm, which exhibits higher speed accuracy for vehicle detection. This considers YOLOv7 algorithm as benchmark model, designs backbone network, uses MobileNetV3 network to extract features. Inspired by structure SPPF, spatial pyramid pooling module is reconfigured...

Battle damage survivability is the prime design criterion of naval ships. Composites and hybrid structures such as polymer coating attract much attention to increase ship survivability. Aiming develop parameter optimization assess underwater explosion shock environment blast-resistant effect efficiently, an approximate numerical method was performed in this preliminary study. An equivalent continuum model based on homogenization theory introduced simulate dynamic behavior coating. The test...

This study proposes a novel phononic crystal (NPC) configuration composed of power exponent prism and cantilever beams to address the vibration problem ship plate structure. According dispersion curves, NPC showed four wide-range complete band gaps bending wave. By combining eigenmode natural modes, it can be found that first gap is low-frequency induced by resonance beams. The second third are medium-frequency gaps, while fourth high-frequency gap. coupled local under superimposition...

The Otsu algorithm is one of the most widely applied threshold-based image segmentation algorithms. However, its rather large calculation amount and poor real-time quality has limited further application. In this paper, a new method combined particle swarm optimization proposed. An improved with improvements particle's best fitness value as inertia weight PSO proposed to improve selecting speed threshold Otsu. experimental results demonstrated that better than original based on standard in...

Numerical simulation of vibration control a submerged stiffened cylindrical structure with active isolators is presented. Vibration transmission from vibrating machinery to the through analyzed by numerical model synthesized frequency response functions (FRFs) and impedances. The coupled finite element/boundary element (FE/BE) method employed study vibro-acoustic behavior fluid-loaded structure. Sound pressure in far-field calculated terms normal acceleration outer surface shell. An adaptive...

This paper discusses the finite-time and fixed-time consensus of nonlinear stochastic multi-agent systems (NSMSs) with randomly occurring uncertainties (ROUs) nonlinearities (RONs) in a leader-following framework. Nonlinear control impulsive pinning protocols are designed to guarantee that follower agents realize leader agent finite time(fixed time). Based on theory, analysis technique, comparison system theory algebra graph some sufficient conditions proposed systems. Then, setting times...

Abstract Auxetic materials have many advantages in strength and energy absorption, which become a research focus of scholars at home abroad. It’s great significance to ship protection structure design that researching deeply on auxetic lattice structures. According the unique properties structures, this paper mainly introduces status impact resistance mechanical new structure. The low-speed impact, high-speed projectile explosion structures is described from three aspects: theoretical,...

A series of triaxial compression tests on dry and saturated limestone (soaked in water solutions Na2SO4 CaCl2 at 0.1 mol / L ionic strengths with varying pH, distilled for 240 days) have been carried out. The corresponding complete stress-strain curves are obtained. influences chemical solution rock mechanical behaviors studied. Results from these indicate that: 1) Dry samples obvious brittle feature. Even if the confining pressure reaching 20MPa, sample is still ruptured suddenly. After...

This paper provided a method to simulate diffraction of Camera Under Display (CUD). To balance the display performance CUD area and front camera image quality, special panel lamination was designed meet requirement. Due micro level size pixel texture, strong optical effect caused on CMOS blurred. built way Modulation Transfer Function different patterns promote promising research direction for under display.

The corrosion products produced from hydrogen sulfide in processing sour crude oils had high pyrophorisity,which could cause fire and explosion accidents.By analyzing the content of orthorhombic sulfur oxidation products,monitoring compositions reaction exhausted gases combining result TG-DTA,the process be divided into primary stage,the secondary stage deep according to oxidizing degree products.In temperature was below 70℃ dioxide not formed.The incomplete reactions ferrous that main form...