Zhiguang Xu

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A special configuration of white-light scanning interferometer is described for measuring the absolute air gap thickness between two planar plates brought into close proximity. The measured gap is not located in any interference arm of the interferometer, but acts as an amplitude-and-phase modulator of the light source. Compared with the common white-light(More)
In this paper, the authors present several throttle and brake control systems for automatic vehicle following. These control systems are designed and tested using a validated nonlinear vehicle model first and then actual vehicles. Each vehicle to be controlled is assumed to be equipped with sensors that, in addition to its own vehicle characteristics,(More)
This paper reports the feasibility of optical coherence tomography (OCT) technology for inspection of bonding quality of microfluidic devices in manufacturing environments. A compact optical-fiber-based OCT is developed and its measurement performance is characterized. A series of microfluidic devices respectively bonded by adhesive tape, thermal method,(More)
This paper introduces an innovative He-Ne laser which exhibits many advantages to current He-Ne lasers. With cat's eye reflector as the reflecting mirror, the new laser can solve the conventional problems of laser adjustment and power stability. Comprehensive experiments are carried out both in a half-external cavity and a full-external cavity He-Ne laser.(More)
A small-scale gap included between two planar plates has found new applications in a broad range of fields in recent years. For example, the micro-scale or nano-scale gaps are precisely formed and controlled to purify the water from the process industry in environmental science, and filter the cells or molecules in biotechnology, pharmaceutical and food(More)
This paper reports the feasibility of optical coherence tomography (OCT) technology for inspection of bonding quality of microfluidic devices in manufacturing environments. A compact optical-fiber–based OCT is developed and its measurement performance is characterized. A series of microfluidic devices respectively bonded by adhesive tape, thermal method,(More)
A special configuration of white-light scanning interferometer is described for measuring the absolute air gap thickness between two planar plates brought into close proximity. The measured gap is not located in any interference arm of the interferometer, but acts as an amplitude-and-phase modulator of the light source. Compared with the common white-light(More)
Precise three dimensional (3D) profile measurements of vertical sidewalls of concave micro-structures are impossible by conventional profiling techniques. This paper introduces a simple technique which can obtain 3D sidewall geometry by means of laser fluorescent confocal microscopy and an intensity gradient algorithm. The measurement principle is: when a(More)
A Moiré fringe approach is developed to identify simultaneously the global and local distortions in hot-embossed polymeric samples. A square grid pattern with a pitch of 63.5 microm is hot-embossed on the polymer substrate. When a reference grid, a polymeric film with the same pattern, is placed on top of the sample, a Moiré fringe pattern is observed and(More)
A microvalve is a key part in a multilayer microfluidic device to control the fluid flow, and its thickness directly determines its performance. In this paper, a three-dimensional measurement technology using a white-light confocal microscope is developed for measuring both the topography and thickness of microvalves. The impact of system parameters and(More)
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