摘要:
Super-miscible blends of nylon copolymers are provided as well as multilayered film structures made therefrom. A nylon composition is a substantially uniform blend of at least one semi-crystalline copolymer I and at least one semi-crystalline copolymer II, wherein the proportion by weight of each of copolymer I and copolymer II. The nylon compositions are extremely uniform, and have only a single melting point rather than individual melting points of the component nylon copolymer parts. Coextruded films of a layer of this nylon composition with an olefin containing polymer are suitable for use as barrier films, such as aroma barrier films, which have reduced curl.
摘要:
A two-piece fastener assembly for securing thermoplastic roof membranes to an underlying roof deck having: a stress plate and a fastener. The stress plate consists of a pre-fabricated metal layer and a thermoplastic layer which are integral with each other. The stress plate has top having three flat surfaces and two circumferential portions, forming ridges or protuberances connecting the flat surfaces. In a method aspect the steps of securing thermoplastic roof membranes to an underlying roof deck, includes: placing a first thermoplastic roof membrane on the roof deck; placing a line of stress plates on the marginal portion of the first thermoplastic roof membrane and securing the stress plates along with the first thermoplastic roof membrane to the roof deck by use of the fastener; placing a second thermoplastic roof membrane to overlap the line of stress plates and the marginal portion of the first thermoplastic roof membrane; and applying heat and pressure to the line of stress plates and the overlapped portion of the first and second thermoplastic roof membranes to fuse them together and provide a waterproof covering over the roof deck.
摘要:
A modular dual-beam source, sample compartment and beam-combining system are provided when used with a monochromator and detector to form a spectrophotometer consisting of: (a) a source module where two ellipsoidal mirrors each produce an image of the light source, and (b) a reflecting sample-compartment module, wherein each side has two plane-mirrors, of the four plane mirrors, three are reference and one is the sample, or (c) a transmission sample-compartment module, wherein each side has two plane-mirrors, and a sample is placed between one pair of plane-mirrors, and (d) a beam-combining module wherein the source images are imaged by a second pair of ellipsoidal mirrors on a reflective chopper that combines the images at a single location that is imaged, external to the module, by another mirror, each module being kinematically located with respect to each other so the system remains optically aligned as modules are interchanged.
摘要:
This invention provides a method and apparatus for mapping the surface of an object, in particular, a transparent object such as anterior and posterior surfaces of a patient's cornea, in a clinically useful time using a single optical system. In a preferred embodiment, a pattern generator projects a pattern of light and dark areas onto a patient's cornea, and a light detector receives patterns reflected from the anterior and posterior surfaces of the cornea. A mapping means generates a three-dimensional map of the anterior and posterior corneal surfaces from information regarding the projected and detected light patterns. The invention can be used to map other transparent objects such as a contact lens or an intraocular device, e.g., an intrastromal ring. The invention can also be used to map the surface of an opaque object.
摘要:
A device and method for subaperture stray light detection and diagnosis in an optical system. A test light beam is generated with a width whose cross sectional area is less than the cross sectional area of a system aperture. Stray light is detected at a system detection surface. Based on the stray light and the location and direction angles of the light beam, potential paths that light may have taken to arrive at the detection surface are determined so as to identify physical features of the optical system that may have produced the stray light. A testing device comprises a test light beam source, preferably including a beam width magnifier, whereby the cross sectional area of the test light beam is made less than the cross sectional area of the system aperture. A relative lateral positioning stage and an angular beam directing stage launch the test light beam into the aperture at a selected position and selected directional angles. A detector and a data processing system produce a data set relating the stray light to the location and directional angles of the test light beam. A light trap and complementary test light beam delivery system are also provided.
摘要:
A method and apparatus for performing a surgical procedure on a patient is described. An incision is made into tissue of the patient to create a tissue pocket. The tissue has an anterior surface. Preferably, the tissue is corneal tissue of an eye. A reflective element is inserted into the pocket. An energy source generates a radiant energy signal, which is directed toward the reflective element. Reflected energy is received from the reflective element. A detector determines the depth of the reflective element below the anterior surface based upon the energy reflected by the reflective element. The speed of transmission of the radiant energy in the reflective element is different (preferably slower) than the speed of transmission of the radiant energy in the tissue. The reflective element may be in the form of a tool on which is disposed a biocompatible polymer layer, the layer comprising trapped air spaces, or a tool having an open space for containing trapped air. The radiant energy may take the form of ultrasound generated by an ultrasonic probe, or light generated by a confocal microscope. The confocal microscope may employ longitudinal chromatic aberration to measure the depth of the reflective element. When employing a confocal microscope, the depth of the reflective element is a function of the reflected energy from the anterior surface and the reflected energy from the reflective element.