Abstract: A method of collecting cells from a specimen and plating such cells onto a slide to create a monolayer. A suspension of cells is filtered to remove unwanted material and monitored to determine if a desired quantity of cells are collected. If insufficient cells are present in the filtered sample, additional suspensions of cells are serially added to the sample and filtered until a desired quantity of cells have been obtained. Devices for collecting samples of cells, for isolating a quantity of cells, and for microscopic examination of a monolayer of cells are also disclosed.

Abstract: A method of welding aluminum alloy workpieces includes the pretreatment of an area adjacent to the seam of the workpiece followed by irradiation of the area with an infrared laser beam having a diameter equal to or greater than the thickness of the workpieces. Substantial subsurface melting of the workpieces is initially generated and the beam can subsequently be scanned along the seam so as to maintain an isotherm corresponding to the melting point of the workpiece at the leading edge of the beam.

Abstract: A laser processing method establishes initial coupling between the laser beam and workpiece by irradiating an intermediate tool positioned adjacent the workpiece. The tool is more absorptive at the laser wavelength than the workpiece so that the efficiency of energy transfer is increased. Subsequent processing is performed by relative movement between the workpiece and beam, either independently of the tool or in conjunction with the tool. During further processing, the beam diameter is increased to be greater than the thickness of the workpiece to enhance the further processing.

Abstract: There is provided a method and apparatus for controlling, in real-time, processing variables in laser processing of materials using fuzzy logic control procedures by embedding expertise in the form of a rule base within a fuzzy logic controller. The method uses a visible light detector as part of the control loop to detect light from the laser-material interaction zone. The light is processed to extract spatial information on the size of the interaction zone and in one aspect determines the number of bright pixels above a pre-defined number which effectively gives the spatial extent or area of the visible light emitted from the interaction zone. From this elemental processing two system input variables are obtained, namely the current number of bright pixels, #BP, and the change in this count since the last calculation, .DELTA.BP.

Abstract: There is provided a method and apparatus for controlling, in real-time, processing variables in laser processing of materials using fuzzy logic control procedures by embedding expertise in the form of a rule base within a fuzzy logic controller. The method uses a visible light detector as part of the control loop to detect light from the laser-material interaction zone. The light is processed to extract spatial information on the size of the interaction zone and in one aspect determines the number of bright pixels above a pre-defined number which effectively gives the spatial extent or area of the visible light emitted from the interaction zone. From this elemental processing two system input variables are obtained, namely the current number of bright pixels, #BP, and the change in this count since the last calculation, .DELTA.BP.

Abstract: A method of modifying the reflectivity and emissivity of a surface of a material comprises the steps of irradiating the surface with a beam of coherent pulsed radiation at a power sufficient to generate a surface plasma and scanning said beam across said surface. Successive pulses of radiation are caused to overlap and chemical change at the surface is promoted by provision of a localized atmosphere. The surface produced has features on a scale of less than 50 microns and is restricted to a depth of less than 10.sup.-3 cm. The body of the material is not affected.

Abstract: A method is described of enhancing the efficiency of laser processing of metals by preprocessing with another laser so as to define a track of reduced reflectivity.

Abstract: A method is described of enhancing the efficiency of laser processing of metals by preprocessing with another laser so as to define a track of reduced reflectivity.

Abstract: A method is described of enhancing the efficiency of laser processing of metals by preprocessing with another laser so as to define a track of reduced reflectivity.

Abstract: A method is described of enhancing the efficiency of laser processing of metals by preprocessing with another laser so as to define a track of reduced reflectivity.