Design of high-intensity ultrasonic sound intensity measurement based on narrow pulse method
The research on high-intensity ultrasonic has taken the delectable achievement in the treatment of cancer and the detection of internal structure for the dam. The rapid and accurate sound intensity measurement of high-intensity ultrasonic transducer is necessary for its application and generalization. The paper introduces the principle of sound intensity measurement, proposes measurement scheme on the basis of the narrow pulse method and also discusses the design of hardware circuit and software.
An Experimental Study on Acoustic Field Measurement of New Phased-array Focused Ultrasound
Objective:Phased-array focused ultrasound is a hot point of researches in thermal physics therapy,of which the acoustic field investigation is the most important section in technology.This paper analyzes the simulation and the experimental results in the acoustic field of new phased-array focused ultrasound.Methods:An acoustic filed measurement system was developed under LabVIEW virtual instruments platform,which is used to measure the acoustic pressure field distributions of the phased-array focused ultrasound in one single focal mode by scanning the acoustic field with a probe hydrophone.Meanwhile,the acoustic field distribution in a single focal mode is simulated with MATLAB toolbox.Results:The experimental result is approximately consistent with theoretical one.Conclusions:The paper demonstrated the correctness of the theoretical model and feasibility and validity of the measurement system.
Dimensional Errors of Fixtures, Locating and Measurement Datum Features in the Stream of Variation Modeling in Machining
Machining processes are usually multi-station processes involving a large number of operations and several locating datum changes. Machining errors are thus introduced, transformed and accumulated as the workpiece is being machined. This paper introduces procedures for expressing the influence of errors in fixtures, locating datum features and measurement datum features on dimensional errors in machining. These procedures are essential in the derivation of the Stream of Variation model of dimensional machining errors using the CAD/CAPP parameters of the machining process. The linear state space form of the Stream of Variation model allows for advanced control theory achievements to be employed in formal solutions to problems in multi-station machining. Modeling procedures presented in this paper were experimentally verified in machining of an automotive cylinder head.