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688 results on '"Zhu, Dongdong"'

1. Invariant sample measures and sample statistical solutions for nonautonomous stochastic lattice Cahn-Hilliard equation with nonlinear noise

Author

Wang, Jintao, Zhu, Dongdong, and Li, Chunqiu

Subjects
Mathematics - Probability, Mathematics - Dynamical Systems, 60H10, 37L60, 37L30, 37L40
Abstract

We consider a stochastic lattice Cahn-Hilliard equation with nonautonomous nonlinear noise. First, we prove the existence of pullback random attractors in $\ell^2$ for the generated nonautonomous random dynamical system. Then, we construct the time-dependent invariant sample Borel probability measures based on the pullback random attractor. Moreover, we develop a general stochastic Liouville type equation for nonautonomous random dynamical systems and show that the invariant sample measures obtained satisfy the stochastic Liouville type equation. At last, we define a new kind of statistical solution -- sample statistical solution corresponding to the invariant sample measures and show that each family of invariant sample measures is a sample statistical solution.

Published
2024

32. Multi-Physical Field Coupling Simulation of Φ100 Cold Crucible-Glass Solidification High Frequency Power Supply

Author

WANG Zexue;LI Yusong;ZHU Dongdong;ZHANG Anqi;HONG Ye;LONG Haoqi;ZHANG Shengdong

Subjects
φ100 cold crucible, high frequency power supply, comsol, multi-physical field coupling, hllw, Nuclear engineering. Atomic power, TK9001-9401, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

High-frequency power supply is an important component of high-discharge glass curing systems for high level radioactive waste (HLLW) of cold crucibles, but because the parameters of each set of high-frequency power supply are not adjustable from the factory and are expensive, it is impossible to study the matching of the power supply parameters to the cold crucible and determine the optimal combination of parameters and the best matching state for the high-frequency power supply. The use of a small, inexpensive and fine-tunable high-frequency power supply to set up a Φ100 cold crucible experimental setup and to investigate the match between the power supply and the crucible is an effective way to solve this problem, but due to the large number of experimental variables and the small amount of valid data available from actual measurements, it is decided to carry out a simulation study of the multi-physics field coupling of a Φ100 cold crucible glass-curing high-frequency power supply. In this paper, COMSOL was used to carry out a multi-physical field coupling simulation of the temperature, flow and magnetic fields of the molten glass liquid, using current strength, frequency and number of turns of the coil as variables. The results show that increasing the current strength and frequency improves the melting capacity, increasing the coil diameter, spacing and number of turns improves the energy utilisation, the coil height is lower in the middle to improve the temperature field and magnetic field distribution, and the round coil and cold crucible are more advantageous than the oval. The initial optimization of the power supply parameters results in a 22.8% increase in the melt cell volume and a 35% increase in the average temperature of the cold crucible, which significantly improves the melting effect of the cold crucible. The simulated experiments provide guidance for the development of the Φ100 cold crucible experiments and lay the foundation for the optimisation of the high frequency power supply and coil parameters.

Published
2023
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45. Effect of brazing temperature on microstructure and mechanical properties of GH4169/AgCuTi+W/Si3N4 joint

Author

XUE Yang, ZHU Dongdong, TAO Feng, DONG Duo, WANG Xiaohong, and MA Tengfei

Subjects
nickel-base superalloy, si3n4 ceramics, brazing, microstructure, mechanical property, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

Nickel-based superalloy (GH4169) and Si3N4 ceramics were connected by AgCuTi composite active filler and high purity W foil which acts as interlayer. The effects of temperature on the microstructure evolution and mechanical properties of GH4169/ Si3N4 brazed joint were systematically studied. The results show that the effective connection of GH4169/Si3N4 brazed joint can be realized by using AgCuTi+W composite filler. The microstructure of the joint is GH4169/TiNi3+TiCu+TiCu2+Ag(s, s)+Cu(s, s)+W+TiN+Ti5Si3/Si3N4. When the brazing temperature is low, the Ti element in liquid filler diffuses to less of the ceramic interface with the filler, and no obvious reaction layer is formed； when the brazed temperature increases to 880 ℃, Ti is enriched on the ceramic side, forming a thickness of 2 μm TiN and Ti5Si3 reaction layer. At this time, the shear strength of the joint is the highest, reaching 190.9 MPa. With the increase in brazing temperature, the content of Ti-Cu compound，which is a brittle compound, increases and the mechanical properties of the joint are greatly reduced. The fracture results show that during the shear process, the crack initiates in the interlayer, and then diffuses into the Si3N4 ceramic matrix， and finally breaks on the side of Si3N4 ceramic.

Published
2022
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