This paper concerns the simultaneous reconstruction of a sound-soft cavity and its excitation sources from the total-field data. Using the single-layer potential representations on two measurement curves, this co-inversion problem can be decoupled into two inverse problems: an inverse cavity scattering problem and an inverse source problem. This novel decoupling technique is fast and easy to implement since it is based on a linear system of integral equations. Then the uncoupled subproblems are respectively solved by the modified optimization and sampling method. We also establish the uniqueness of this co-inversion problem and analyze the stability of our method. Several numerical examples are presented to demonstrate the feasibility and effectiveness of the proposed method.

<abstract><p>This paper is concerned with the inverse problem of determining an obstacle and the corresponding incident point sources in the Helmholtz equation from near-field scattering data. An optimization method is proposed to simultaneously recover both the obstacle and source locations. Moreover, a two-step sampling scheme with novel indicator functions is proposed to produce a good initial guess for solving the optimization problem. Theoretically, we analyze the convergence properties of the optimization method and the behaviors of the indicator functions. Several numerical examples are presented to show the effectiveness of the proposed method.</p></abstract>

Nickel-based alloy Inconel718 is a difficult-to-cut material due to lower thermal conductivity, affinity to react with tool material, the cutting tools wear very rapidly due to the high cutting temperature and high cutting force. It is important to choose tool material reasonably. In this paper, cutting performance of the multi-layer CVD-coated (TiN/Al2O3/TiC) tool and PVD-coated (TiAlN) tool were evaluated by cutting temperature, cutting force, tool wear and tool life. The results showed that PVD-coated (TiAlN) tool was suitable for cutting Inconel718.

Combined with the 110KV line breaking protection action, this paper pointed out the main problems is that the switch of 110KV side is not disconnected. It leaded to protection action of T type transformer in 110KV line. Because of the problem in switch operating of 110KV line, the three phases are not disconnecting all. It caused insulation damage of the 110KV main transformer that the 110KV line is non-phase, and then it caused tripping main transformer protection. This paper proposes improvement measures and precautions for such situations.

This paper analysis the low power load forecasting accuracy in summer deep. It found the factors affecting accuracy rate of power load forecasting in summer, and proposed the measures to increase the load forecasting accuracy.