Scanning laser method

The optical method for measuring substrate curvature is generally convenient for in-situ measurement of film deposition stress in CVD and MBE systems, provided that optical access is provided to the substrate and that the specimen is mounted in a manner which facilitates unconstrained curvature evolution in one direction. One of the most common optical methods of 

A linear regression analysis of the versus r data then provides an estimate of K from which the mean stress can be determined using the Stoney formula 

The time involved in scanning a large area of a substrate could also limit the use of this method as a real-time probe for curvature evolution in some applications. In addition, a major limitation of this technique is the sensitivity of this serial scanning method to mechanical vibrations, such as those commonly encountered in ultra-high vacuum chambers. This limitation could be overcome by the introduction of a beam-sphtter in the path of the laser to introduce multiple incident beams on the specimen, as described by Schell-Sorokin and Tromp (1990) and Marunez et al. (1990). The reflections of these beams could then be independently monitored by a CCD camera. 

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Fig. 2.8. Schematic illustration of the scanning laser method for measuring substrate curvature.

Fig. 2.25. Measured normalized curvature versus normalized mismatch strain for Si wafers with W films. The data points represent experiments conducted for different combinations of wafer diameter, wafer thickness and film thickness. The filled circles correspond to curvature measurements made by Finot et al. (1997) using the scanning laser method for the pre-bifurcation data points or the grid reflection method for the post-bifurcation data points. The other symbols denote experiments using the coherent gradient sensor method. Superimposed on the experimental data are the predicted trends for the stable symmetric and stable asymmetric cases replotted from Figure 2.24 with i = 0.26.

Leonas K K 1998 Confocal scanning laser microscopy a method to evaluate textile structures Am. Dyest. Rep. 87 15-18 Wilson K R ef a/1998 New ways to observe and control dynamics Proc. SPIE 3273 214-18... 

Flowever, the object being analyzed has to be removed from the tissues. Thus, information about the distribution of the target in the organism or in the cells is inevitably lost. What is now needed is a technology to acquire information about the distribution of the biomolecule simultaneously with its identification. The method used for this purpose, called imaging mass spectrometry (IMS), is as follows. The tissue sample is cut into thin slices, and a matrix that assists the ionization of macromolecules is spread onto these slices. The macromolecules are then ionized by a scanning laser, and the generated ions are detected and analyzed by MS.1... 

Fig. 6. Schematic diagram of the steps involved in the cookie cutter method of cell selection. (A) Cells are grown on plastic Petri dishes covered with a darkened nylon film. (B) Based on fluorescence intensity image scans using a stage-scanning laser microscope, rare event cells are identified, and octagonal welds are made around those cells to fuse the film to the dish. (C) The film is then peeled away from the dish. (D) The cookies containing the desired cells remain on the dish so that the cells may be analyzed further or subsequently cloned.

A typical DNA array fabrication and application process involves three major steps. First, nucleic acids (the capture sequences or probes) are immobilized at discrete positions on surface activated substrates. Secondly, the resulting array is hybridized with a complex mixture of fluorescently labelled nucleic acids (the target), and thirdly subsequent to hybridization, the fluorescent markers are detected using a high-resolution scanning laser that quantifies the interaction. This chapter focuses on the first of these processes and provides the reader with an overview of substrates, surface activation methods and dehvery systems available for nucleic acid immobilization. 

Auty, M.A.E., Fenelon, M.A., Guinee, T.P., Mullins, C., Mulvihill, D.M. 1999. Dynamic confocal scanning laser microscopy methods for studying milk protein gelation and cheese melting. Scanning 21, 299-304. 

Using myosin manipulation or scanning probe methods, these ATP hydrolysis coupled steps have been resolved into multiple stochastic substeps (Fig. 12.Id). The laser trap method, however, has not been able to resolve substeps. We attribute this to the large scanning probe slowing the substeps to a time within our system s time resolution. The size of the substeps was 5.5 nm, corresponding to the interval of actin monomers on a protofilament in a two-stranded filament. Substeps occurred both in the forward and back-... 

D Haese E, Dumon I, Werbrouck H, Dejonghe V, Herman L (2005) Improved detection of Mycobacterium paratuberculosis in mfik. J Dairy Res 72 125-128 Guyomard S (1997) Vahdation of a scanning laser system for microbiological quality control (QC) analysis. Pharm Technol Fur (September) 50-54 Jones DL, Brailsford MA, Drocourt JL (1999) Solid-phase, laser-scanning cytometry a new two-hour method for the enumeration of microorganisms in pharmaceutical water. Pharmacopeia Forum 25 7626-7645... 

Kamentsky, L. A. (2001) Laser scanning cytometry. Methods Cell Biol. 63, 51-87. 

Based on the fact that the lens is embryologically derived from the same ectodermal source as comeal and conjunctival epithelium, Sivak et al. (1992) used an automated scanning laser system to monitor spherical aberration and transmission of the lens in culture. They believed that this method of measuring lens damage compared favorably with standard Draize. scores. 

A major advance in the utility of laser spectroscopy came as a result of the development of multiphoton ionization MPI as a means of detection of multiphoton absorption by molecules [1]. The resonance encountered as the n-photon energy of a scanning laser becomes coincident with that of a molecular excited state is evidenced by a large increase in ionization rate. Since single ionization events can be detected with near unit efficiency, this results in a very sensitive means of detecting weak multiphoton absorption. MPI is a more widely applicable method than laser induced fluorescence since it can be used for non-emitting states. 

While method (a) is often used for high-resolution fluorescence spectroscopy with slow scan rates or for tuning pulsed dye lasers, method (b) is realized in a scanning confocal FPI (used as an optical spectrum analyzer) for monitoring the mode structure of lasers. 

The scanning infrared laser method sends an oscillating laser beam into a suspension and detects back-scattered infrared light. The random chords within particles are thus measured and this information is related to the particle size distribution of the suspension. This method can be used to... 

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