Abstract: A method for modelling the electron density distribution of a macromolecule in a defined asymmetric unit of a crystal lattice having locations of uniformly diffracting electron density includes the steps of: producing an initial distribution of scattering bodies within a asymmetric unit having the same dimensions as the defined asymmetric unit; calculating scattering amplitudes of the initial distribution and determining the correlation between the calculated scattering amplitudes and the normalized amplitudes; moving at least one of the scattering bodies within the asymmetric unit to create a modified distribution; calculating scattering amplitudes and phases of the modified distribution and determining the correlation between the calculated amplitudes and the normalized values; and producing a final distribution of scattering bodies by repeating moving and calculating steps until the correlation between the calculated scattering amplitudes and the normalized amplitudes is effectively maximized, the final di

Abstract: A method of fabricating a waveguide is described minimizing to a desired degree the effect of minor variations caused, for example, during manufacture from an ideal dimension to obtain a coupling of energy between two different frequencies of optical radiation propagated in the waveguide.

Abstract: This invention relates to an improvement in nucleic acid hybridization technology. Nucleic acids bind to complementary partners in a predictable manner such that the detection of complementary partners is possible. The acceleration of the binding process is desired objective and will find broad application in a variety of industrial, medical, and research uses. In particular this invention relates to the acceleration of nucleic acid hybridization by heterogeneous nuclear ribonucleoproteins [hnRNPs].

Abstract: A method of making an integrated, microminiature, electric-to-fluidic valve. The method comprises, in one embodiment, anisotropically etching a cavity in a silicon wafer to form a thin membrane at the bottom of a trench. Then a second wafer is etched to form an exit path surrounded by a valve seat positioned such that when these two wafers are sandwiched together, the valve seat lies under the membrane. An input passageway joining a manifold cavity formed around the valve seat is then etched in the surface of the second wafer which will mate with the diaphragm side of the first wafer. The two wafers are then bonded together after suitable alignment. A third pyrex wafer is then coated with a resistor material which will be over the cavity in the first wafer when the first and third wafers are bonded together. Conductive leads and wire attach pads are also formed. Finally, a fill hole is etched into the third wafer over the position of the cavity such that the cavity can be filled.

Abstract: Integral sharp tips on thin film cantilevers are produced by forming a rectangular silicon post on a (100) silicon wafer. Etching the top of the post leaves sharp silicon tips at the corners of what remains of the silicon post. A silicon dioxide cantilever with an integral tip is thermally grown over the silicon wafer and the sharp silicon tips.

Abstract: A moving slab laser includes a slab carriage driven to-and-fro along a precise rectilinear reciprocal path by a liner motor under the control of a computer. The reciprocal motion of the slab is precisely guided by cross roller ways or ball bushing bearings to minimize non-rectilinear motion-dependent output beam steering effects. In one embodiment, the lasant slab is separated into a pair of axially spaced geometrically identical portions which are reciprocated in opposite directions to cancel motion direction dependent beam steering effects.

Abstract: Vaccines comprising peptide sequences corresponding to immunorecessive determinants in gonorrhea pilus protein are disclosed. The vaccines are effective in protecting human subjects against infection by a wide range of gonorrhea strains by raising antibodies which interfere with the colonization of the epithelium by the infecting bacteria or which enhance phagocytosis.

Abstract: In a high average power slab laser, heat generated in the laser slab is conducted through a thin layer of thermally conductive gas, such as hydrogen, helium or air, and then through an optically transparent window into a flow of liquid coolant. In a preferred embodiment, a second flow of liquid coolant is employed for cooling of the pumping lamps such lamp liquid coolant flow being partitioned from the slab liquid coolant flow by means of an optically transparent partition through which the pump radiation is directed from the lamps to the slab. In another embodiment, the slab coolant flow is controlled so as to operate the laser slab in a self-annealing temperature regime, whereby thermal stresses are annealed out in use and higher average output beam power is obtained.

Abstract: A pair of small diameter optical fibers are arranged in a side-by-side configuration, the first fiber providing a passive guide for pump light, and the second fiber formed of a material, such as Nd:YAG which has amplifying properties at the signal frequency. The signal to be amplified propagates through the second fiber from the active material, resulting in amplification of the signal. The first fiber is pumped from one or both ends, utilizing a cone shaped rod which is optically coupled thereto. A large diameter beam of collimated pump light enters the cone shaped rod, where total internal reflections on the cone walls compress the beam to a small, fiber-size diameter for absorption by the active fiber. The light input to the cone-shaped rod is produced by plural, high power laser diodes, and is collimated by microlenses. By utilizing the cone-shaped rod to couple light from the high power diode lasers to the pump fiber, high pump power densities can be achieved, yielding increased amplification.

Abstract: Two coaxial acoustic beams, one focused and the other unfocused, are used to measure changes in temperature within a localized region in a body. The focal region of the focused beam is located at the area to be measured. Changes in the relative phase angle between the two beams are indicative of changes in acoustic properties occurring at the focal region. Since the two beams have generally the same propagation path outside of the focal region, they will be similarly affected by acoustic variations which occur there, so there will not be any relative phase change between them due to such variations.

Abstract: An acoustic microscope and method are disclosed in which an object under investigation is excited by two energy sources. Acoustic waves are propagated from the heated area of the object and the waves are detected and analyzed.

Abstract: The wavelength of an optical pump beam is down converted to a longer wavelength in a Raman active gaseous medium by stimulated Raman scattering. The Raman active gaseous medium is contained in the space between a pair of optical reflectors of an optical resonator of the type for producing a focus of the optical beam energy at a point intermediate the length of the resonator within the Raman active medium to enhance conversion of pump energy into the output longer wavelength of the Stokes wave. The pump beam is directed into the optical resonator at an angle to the optical axis of the optical resonator such that the optical beam path is folded back and forth within the optical resonator to cause the beam spot to walk over the surfaces of the reflectors and out of the optical resonator.

Abstract: A tunable source of infrared radiation is obtained by irradiating an assemblage of Raman active gaseous atoms or molecules with a high intensity pumping beam of coherent radiation at a pump frequency .omega..sub.p to stimulate the generation of Stokes wave energy at a Stokes frequency .omega..sub.s and to stimulate the Raman resonant mode at the Raman mode frequency .omega..sub.R within the irradiated assemblage where the pump frequency .omega..sub.p minus the Stokes frequency .omega..sub.s is equal to the Raman mode frequency .omega..sub.R. The stimulated assemblage is irradiated with a tunable source of coherent radiation at a frequency .omega..sub.i to generate the output infrared radiation of the frequency .omega..sub.0 which is related to the Raman mode frequency .omega..sub.R and the input wave .omega..sub.i by the relation .omega..sub.0 =.omega..sub.i .+-..omega..sub.R. In one embodiment the interaction between the pump wave energy .omega..sub.p and the tunable input wave energy .omega..sub.

Abstract: A method of and apparatus for imaging objects utilizing acoustic waves wherein an acoustic beam or beams are generated at one or more frequencies and are focused into proximity with the object to generate output acoustic energy at a different frequency or frequencies resultant from nonlinear interactions with the resultant production, after detection and conversion to electric output signals, of high resolution, enhanced images.

Abstract: An acoustic scanning apparatus is described having an acoustic grating for scattering waves into a focused beam. Surface acoustic waves are generated by a chirp signal generator and are introduced along one surface of the scanning apparatus. These waves propagate along the surface, are scattered by the acoustic grating and are thereby converted into bulk acoustic waves. The bulk acoustic waves converge into a focused beam inwardly directed at an angle to the surface acoustic waves. The focused beam scans at substantially the same speed as the surface acoustic waves traveling along the surface of the apparatus. The acoustic grating can also be used to convert bulk waves to surface acoustic waves as either a variable chirp rate generator or a variable pulse compression filter.

Abstract: Method and apparatus for making a hologram that controls both the amplitude and the phase of a reconstructing beam of light at each point on the surface of the hologram. The hologram is a transparency made from a conventional, color reversal photographic film that has multiple emulsion layers that are each selectively photosensitive to light of different wavelengths. The desired image to be produced from the hologram is initially processed into a matrix of Fourier transformed amplitude coefficients and a matrix of Fourier transformed phase coefficients. The hologram is made by first exposing the photographic film to an illumination pattern of the Fourier amplitude coefficients using light having a spectrum to which one of the emulsions is selectively photosensitive. The film is next exposed to an illumination pattern of the Fourier phase coefficients using light having a wavelength to which another emulsion of the film is selectively photosensitive.

Abstract: An acoustically scanned, optical imaging system for converting patterns of light into electrical signals. The system includes a monolithic convolver that scans incident light patterns using two counter propagating acoustic waves. Located in front of the convolver is an opaque grid that places a spatial periodicity into the light patterns. When the frequencies of the two acoustic waves propagating in the convolver are selected so that the difference between them is a function of the spatial periodicity placed in the light patterns, the minimum threshold signal or dark current from the convolver is substantially reduced. The imaging system also includes four alternative signal generating and processing circuits that can provide a one dimensional scan, a fast Fourier transform and a Fresnel transform of the light patterns incident on the convolver. Patterns of colored light also can be convolved into electrical signals by using colored filters as the grid.