Chung Yuan Christian University

About: Chung Yuan Christian University is a education organization based out in Taoyuan City, Taiwan. It is known for research contribution in the topics: Membrane & Fuzzy logic. The organization has 9819 authors who have published 11623 publications receiving 213139 citations. The organization is also known as: Tiong-gôan-tāi-ha̍k & CYCU.

Automatic optical inspection for detecting defects on printed circuit board inner layers

Abstract: This paper studies automatic optical inspection for detecting defects on the printed circuit board inner layer. The development of this study can be divided into five stages, they are reference image rebuilding, inspection image normalization, image subtraction, defects separation and defect classification. In the image subtraction stage, the difference between the reference image from the printed circuit board design and the inspected image is checked for defects. Each defect region is separated using a defect outer boundary tracing method. A boundary state transition method is proposed to classify the defect types. This system can recognize eight defect types, open, mouse bite, pinhole, missing conductor, short, spur, excess copper and missing hole. In addition, a comparison with the methods described in the literature is made, proving that the proposed method produces better results .

Thermal and anticorrosive properties of polyurethane/clay nanocomposites

Abstract: A montmorillonite clay has been modified with two different quaternary ammonium salts, dilauryldimethylammonium bromide (LD) and 4,4′-diaminodiphenylmethane (AP), to form the corresponding organophilic clays, LDM and APM. Two series of PU/clay nanocomposite materials, PU/LDM and PU/APM, were then prepared by the reaction of appropriate amounts of PPG, TDI and 1,4 butandiol, followed by addition of the various amounts of LDM or APM. The X-ray diffraction patterns and transmission electron micrographs of the nanocomposites revealed that the modified clay galleries were exfoliated or intercalated in the polyurethane matrix. In comparison with the corresponding pure PU, the results of the TGA and LOI measurements showed that the thermal stability and the flame retardancy of the PU/clay nanocomposites were significantly enhanced due to the presence of the dispersed nanolayers of the organophilic clay in the PU matrix. Using the Tafel method, the results of the electrochemical measurements, which included the corrosion potential, polarization resistance and corrosion current, showed that all the PU/clay nanocomposites, even with low clay loading, in the form of coating on stainless steel disk (SSD) exhibited better corrosion protection over the pure PU. The SSD coated with the composite containing 2 wt% of APM showed the lowest corrosion rate, which was one order lower than that of the SSD coated with the pure PU.

Utilization of 3-D elastic transformation in the registration of chest X-ray CT and whole body PET

Abstract: Describes a 3-D elastic transformation which compensates for the non-rigid deformation of the chest that is seen in X-ray CT relative to PET images of the thorax. X-ray CT is widely used for detection and localization of lesions in the thorax. Whole Body PET with 18-FDG is accepted for staging and for measuring tumor response to therapy. The combination of these two modalities to locate metabolically active tumors in CT images should prove to be of significant value in lung cancer staging and treatment planning. Due to the differences in the acquisition conventions and scan duration, the subject's arms are positioned overhead for X-ray CT or at the side for PET, causing a change in the shape of the thorax, requiring non-rigid transformations to achieve proper registration. Techniques to register chest X-ray CT and Whole Body PET images were developed and evaluated. The accuracy of 3-D elastic transformation was tested by phantom study. Studies on patients with lung carcinoma were used to assess the technique for localizing 18-FDG uptake and for correlating PET transmission to X-ray CT images. Results showed that the elastic transformation provided an accurate alignment and reliable correlation of the detailed anatomy of the CT with the functional information of the PET images.