Background: Simulation of the emitted acoustic field is crucial to the design of ultrasound transducers. The method based on the spatial impulse response (SIR) and aperture discretization provides a powerful tool to study the acoustic field emitted by a transducer with complex aperture geometry and sophisticated apodization/excitation pattern. Methods: In this work, a new method based on the dynamically refined sub-elements (SE) is employed to discrete the aperture and generate the SIR. Then, these SIRs are convoluted with the excitation pulse to get the acoustic pressure (AP) signal. When calculating the SIR with this method, the slowly changed time flight from a SE to a field point (FP) is approximated with a step function, and the fast changed length of intersection between a SE and a spherical wave centered at a FP is accurately estimated with the areas of the sub-parts (SP) which are given by the dynamically refined SE. Results: Simulations of the acoustic field created by a focusing transducer array and a hollow structured point focusing transducer indicate that the proposed new method can give similar data accuracy with a sampling frequency 16 times lower than the conventional time tracing SE (TTSE) based method. The computational cost is also reduced by nearly one order of magnitude. Conclusions: A new method is proposed to simulate the acoustic field emitted by transducers with complex geometrical structure and sophisticated apodization/excitation patterns. The required sampling frequency with the new algorithm is greatly reduced compared to that of the conventional TTSE-based method; thus, the efficiency of the acoustic field calculation is improved significantly.

Process database support system is one of the key technologies for green manufacturing implementation. In this paper, the process database support system for green manufacturing was developed with Browse/Server (B/S) three level structure on the basis of Web, which has the function of distributed processing and storage of the data. The composing and its green characteristics were discussed in detail respectively. Furthermore, the key develop technology of the database system, such as network requirement, assistant planning and green assessment of process and the accessing to the database were analyzed. A case study was performed to illustrate and examine the validity of the database system.

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