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Objective To reasonably evaluate the energy absorption reliability index of anti-climber devices, a reliability analysis method based on ISSSM (improved sinusoidal and surrogate model) is proposed. Method Firstly, a finite element model for anti-climber device collision is established. Secondly, the rationality of the finite element simulation model is verified based on the collision test data of the anti-climber device. Then, based on the principles of sum of sine function construction, the basic form of the force-displacement function for the anti-climber device collision process is clarified. According to the energy absorption consistency criterion, the anti-climber device energy absorption ISSSM is constructed. Combining reliability theory, a reliability analysis model for anti-climber device energy absorption is established. Finally, a specific model of anti-climber device is studied, and its energy absorption reliability index is evaluated. Result & Conclusion The constructed energy absorption ISSSM can reasonably reproduce the mechanical characteristics of the anti-climber device collision energy absorption process. When the coefficient of variation increases from 0.05 to 0.1, the energy absorption reliability index decreases from 3.07 to 1.53.

Structured illumination microscopy (SIM) can achieve optical sectioning with high resolution, and have aroused extensive research interest. In SIM, a set of high-contrast illumination patterns are projected onto the sample to modulate the surface height information, and then, a decoding algorithm is applied to the modulated pattern images for high-quality optical sectioning. Applied to samples with large dynamic range of reflectivity, however, SIM may fail to achieve high quality sectioning for accurate surface reconstruction. Herein, an active digital micromirror device (DMD) based illumination method using per-pixel coded strategy is proposed in SIM to realize high-quality measurement for surface with complex reflection characteristics. In this method, the mapping relationship between DMD and the camera is established pixels by pixels, which enables the illumination intensity on the sample surface can be flexibly modulated by DMD pixel-level modulation corresponding to reflectivity distribution of the surface, and allows the camera pixels always to have reasonable exposure intensity for high precision measurement. More importantly, we put forward an adaptive light intensity control algorithm to improves the signal-to-noise ratio of acquired images without compromising modulation depth of pattern and measurement efficiency. Extensive comparative experiments were conducted and demonstrated that the proposed method can retrieve the surface morphology information of micro-scale complex reflectivity surfaces with high accuracy. [ABSTRACT FROM AUTHOR]

Using different experimental methods, the pore radius ranges vary greatly, and most scholars use a single experiment to study pore structure, which is rarely consistent with reality. Moreover, the numerical models used in different experiments vary and cannot be directly compared. This article uniformly revised all experimental data into a cylinder model. Quantitative analysis of the full-scale pore distribution is established by mercury withdrawal–CT data, and semi-quantitative distribution is obtained by mercury–NMR–cast thin section imaging. In this paper, we introduce the tortuosity index (τ) to convert the CT ball-and-stick model into a cylinder model, and the pore shape factor (η) of the cast is used to convert the plane model into the cylinder model; the mercury withdrawal data is applied to void the influence of narrow throat cavities, and the NMR pore radius distribution is obtained using the mercury-T2 calibration method. Studies have shown that the thickness of bound water is 0.35~0.4 μm, so the pores with different radius ranges were controlled by different mechanisms in the NMR tests, with pores < 0.35~0.4 μm completely controlled by surface relaxation, including strong bound water and weak bound water; pores in the 0.4~4 μm reange were controlled by surface relaxation; and pores > 10 μm were completely controlled by free relaxation. The surface relaxivity rate of fine sandstone was 18~20 μm/s. The tortuosity index τ was generally 1~7; the larger the value, the more irregular the pores. The pore shape factor η was generally 0.2~0.5; the smaller the value, the more irregular the pores. Mercury withdrawal–CT scan data can quantitatively determine the pore radius distribution curve. The coefficient of the logarithm is positive considering porosity, and the constant is negative considering porosity. Permeability controls the maximum pore radius, with a max pore radius > 100 μm and a permeability > 1 mD. Mercury withdrawal–NMR–cast thin section imaging data can semi-quantitatively establish a pore radius distribution histogram. The histogram represents quasi-normal, stepped, and unimodal data. When 60 μm is the inflection point, if a large proportion of pores measure > 60 μm, good reservoir quality is indicated. If a large proportion of pores measures < 60 μm, the permeability is generally <0.5 mD. [ABSTRACT FROM AUTHOR]

The article introduces the principle of Magnetic Controllable Reactor(MCR) in power system applications, the temperature 1rise test is the important type test in the factory, but it will lead to errors of the temperature rise test results in the factory because the test conditions in the factory is different from the actual operation circuit. In this paper, a compensation method for temperature rise test is introduced, which can make up for the shortcomings of temperature rise test in factory, and the results of simulation by PSCAD and measurement show that the method presented in this pape is effective.

This paper expands the damping torque coefficient analysis (DTCA) for studying the small‐signal stability of permanent magnet synchronous generator (PMSG)‐based wind turbine (WT) under virtual synchronous generator (VSG) control with consideration of WT dynamics. Firstly, the typical VSG is implemented in the grid‐side voltage source converter (GSVSC), which enables selfsynchronization without phase‐locked loop (PLL). The maximum power point track (MPPT) algorithms are utilized to give the power reference for VSG. Then, the corresponding inertia and damping support can be provided by the kinetic energy of PMSG. Based on the established model, the DTCA is analytically conducted to not only reveal the key factors that influence the WT stability but also provide guidance for parameter tuning. As a result, it is important to find that the WT dynamics impair the damping and even lead to system instability. Moreover, the minimum value of VSG damping control parameter is analytically given to ensure the system stability under any load below the rated wind speed. Finally, the case studies considering one single PMSG connected to a large grid with and without inclusion of WT dynamics are performed and compared to demonstrate the accuracy of the proposed model and evaluate the applications of DTCA. [ABSTRACT FROM AUTHOR]