No abstract

Lambda Red recombineering is a DNA cloning and engineering technique involving recombination between homologous regions. The homologous recombination is mediated by the lambda Red genes consisting of red alpha, red beta and gam. Three lambda Red recombineering systems are currently available; the first is the plasmid-based system, in which lambda Red genes were cloned into temperature-sensitive plasmids; the second is the prophage-based system, in which lambda Red genes containing prophage were integrated into the Escherichia coli genome; the third is the integrative form system, characterized by the integration of lambda Red genes (or their counterparts) into the E. coli genome. In this study, a novel integrative form recombineering host, E. coli LS-GR, was constructed through the integration of functional recombineering elements including lambda Red genes, recA, araC and aacC1 into the E. coli DH10B genome. LS-GR shows high recombination efficiency for medium copy number vector and single copy number BAC vector modifications. The results indicate that LS-GR could be used as a general recombineering host strain.

In phase measuring deflectometry (PMD), a camera observes a sinusoidal fringe pattern via the surface of a specular object under test. Any slope variations of the surface lead to distortions of the observed pattern. Without height-angle ambiguity, carrier removal process is adopted to evaluate the variation of surface slope from phase distribution when a quasi-plane is measured. However, in the usual measurement system, the carrier phase will be nonlinear due to the restrictions of system geometries. In this paper, based on the analytical carrier phase description in PMD, a carrier removal method is proposed to remove the nonlinear carrier phase. Both the theoretical analysis and the experiment results are presented. By comparison with reference-subtraction method and series-expansion method, this proposed method can achieve carrier removal process with only the measurement of one single object, as well as high accuracy and time-saving.

The demands of the less-defective and high-flatness wafers are urgent in many wafer based technologies ranging from micro-electronics to the current photovoltaic industry. As the wafer becomes thinner and larger to cope with the advances in those industries, there is an increasing possibility of the emerging of crack and warp on the wafer surface. High-accuracy inspection of defects and profile are thus necessary to ensure the reliability of device. Phase measuring deflectometry(PMD) is a fast, cost-effective and high accuracy measurement technology which has been developed in recent years. As a slope measurement technology, PMD possesses a high sensitivity. Very small slope variation will lead to a large variation of the phase. PMD is very possible to have a good performance in the wafer inspection. In this paper, the requirements of the wafer inspection in the industries are discussed, and compatibility of PMD and those requirements is analyzed. In the experimental work, PMD gets the slope information of the wafer surface directly. The curvature or height information can be acquired simply by the derivation or integral of the slope. PMD is proved to make a superior result in high-precision defect detecting and shape measurement of wafer by the analysis of experiment results.

In phase measuring deflectometry, the measurement accuracy is relatively low with low reflectivity surface. Based on temporal phase unwrapping, two main noises are reduced to improve accuracy by least-square method and 3-frame method.