Papers by Author: L.B. Zhang

Abstract: A single-chip silicon condenser microphone with a sandwich diaphragm and an electroplating perforated copper backplate has been developed. The sandwich diaphragm is designed to have a slight tensile stress. The backplate is made using copper electroplating technology and perforated with circular holes. Perforated circular holes on backplate are laid out as hexagon to adjust air-gap damping between diaphragm and backplate to critical damping to enlarge frequency bandwidth of microphone. Fabrication is simple enough and only needs five photolithography marsks. Measurements show the open-circuit with 9V bias voltage reaches 5.45mv/Pa in 1KHz, pull-in voltage is 14V, and the flat frequency response within 3Db is from 100Hz to 20KHz. The performances of microphone meet the requirement of industrial use. Thereby, it has promising prospect for industrial and commercial field.

Abstract: The mechanism responsible for scanning probe field-induced oxidation in ambient air is attributed to an electrochemical process, i.e., anodic oxidation or anodization,after the analyses is given of a surface of a sample exposed to air. The effects of biases, tip speeds on morphology of field-induced oxidation, are introduced and deduced in the form of kinetics formula of oxidation growth. The field-induced oxidation of hydrogen-passivated Si (Si:H)using contact-mode AFM in air at room temperature is investigated. The result achieved from the experiment and that drawn from theoretical analysis are identical, which indicates the accuracy of the experimental operation.This experiment suggested that it may be used for further investigation of field-induced oxidation technology.

Abstract: The Mahalanobis distance feature proposed by P.C .Mahalanobis, an indian statistician. In this paper, we propose a new concept, Local Region Mahalanobis Distance feature –LRMD feature, we shall discuss the structure form, the obtaining methods of LRMD feature from an image and the relations between the LRMD feature and wearing and breakage states of cutting tools. The new research results indicate that the method of automatic on-line cutting tool condition monitoring based on LRMD feature can has better inspect result than the method of Mahalanobis Distance feature.

Abstract: Scanning probe microscopy (SPM) has proved to be a powerful tool not only for imaging but also for nanofabrication. SPM-based nanofabrication comprises manipulation of atoms or molecules and SPM-based nanolithography. SPM-based nanolithography, referred to as scanning probe lithography (SPL) in this review, holds good promise for fabrication of nanometer-scale patterns as an emerging generic lithography technique that STM, AFM, and SNOM are directly or otherwise used to pattern nanometer-scale features under appropriate conditions. Patterning methods including mechanical SPL, electrical SPL, thermal SPL, and optical SPL, are described in terms of SPL mechanisms. The newly developed variations of the above-mentioned SPL methods such as dip pen nanolithography, nanoshaving and nanografting, replacement lithography, constructive nanolithography, nanojet lithography, and electrostatic lithography, are also illustrated respectively. Analyses of prospective application of these SPL methods are presented finally.

Abstract: A new intelligent tool condition monitoring technique for metal cutting process is proposed. Fiest, the frequency spectrum analysis of the audio signal during cutting process, the pixel space projection analysis and equal gray pace analysis of the images of machined workpiece surface are introduced. Then combined the results of the audio signal analysis and the workpiece surface image analysis with artificial neural network, we implemented the intelligent tool condition monitoring based on multi-information fusion. The experimental results indicate that this method can recognize the tool condition effectively and improve the dependability of tool condition monitoring.