Abstract: Optical fibres comprised of a halide glass incorporating color centers, for example fluoride fibres, can behave as a laser or an amplifier when maintained at a low temperature, typically 77.degree. K., and optically pumped. A laser may be comprised by a length of such a fibre (1) wound on a spool (2) and disposed in liquid nitrogen (4), the ends of the fibre are outside of the coolant and associated with input and output mirrors (5,6) which define the extremities of a lasing cavity. An optical pumping signal (7) is provided by a laser (8), for example a Krypton ion laser operating in the visible range. The output of the fibre laser is in the infra-red. Higher gain than with conventional color center lasers is achieved due to the longer interaction length and cooling problems are overcome.

Abstract: In order to connect the case parts (10, 12) of several potentiometer planes, a heat-shrinkable sheath (36) is used. On the outer faces (18, 20) recesses are provided along the contact faces (14, 16), between which recesses a connecting bead (30) is formed. The bead has a knurled edge (34). A heat-shrinkable sheath (36) is tightly applied, after heating and shrinking, to the bead (30), thus connecting the case parts (10, 12) in an axial and angular manner.

Abstract: An optical sensor device uses surface plasmon resonance to detect the presence of a specific material. A transparent body (12) is coated with a thin gold film (14) which film may be coated e.g. with an antibody material. The arrangement is illuminated with a divergent light beam and light internally reflected from the gold film is detected by a photodiode array (16). The dielectric conditions adjacent the gold film determine the position of the surface resonance angle, this being indicated by a dark area on the detector array.

Abstract: A bipolar transistor structure (1) which can be used in an integrated circuit where bipolar (1) and CMOS transistors (2,3) are formed simultaneously on one substrate. In integrated circuit form the material, for example polycrystalline silicon, used for the gates (11,21) of the CMOS transistors is also used for the emitters (29) of the bipolar transistors, the collectors of the bipolar devices are comprised by doped wells (5) in the substrate (4) and the base contacts of the bipolar devices are comprised by regions (27,27a) equivalent to source and drain regions (17,18) of the n-well MOS transistors and bridged by base implants (28). The conventional CMOS processing is modified by the addition of two masking steps and one implant (base implant).

Abstract: An injection laser package having a housing and an optical fiber pigtail extending onto a sub-mount of a mount with the sub-mount being formed of a plurality of thick film layers which incorporate a resistance heating element and etched conductors which are insulated from a narrow solder pad. With the end portion of the fiber in alignment with the injection laser chip, a current is applied to the conductors to heat the sub-mount and melt the solder pad to thereby hold the fiber exactly in alignment with the chip. The portion of the fiber extending between the sub-mount and the inner end of the entrance support tube remains unsupported and thereby flexible so that external stresses on the package housing and, particularly, a support tube do not transfer any strain to the end portion of the fiber so that alignment with the injection laser chip is maintained.

Abstract: A device for inserting and withdrawing a core in plastic and die cast molds. A rotatable cylindrical nut is located within the hollow cylindrical interior of a support housing. The nut has a threaded inner cavity. A non-rotatable slide extends through an aperture in the housing, the slide having a threaded end engaging the threaded inner cavity. When the nut is rotated, the slide is either extended or retracted through the aperture depending on the direction of rotation of the nut. A mold core is affixed to the slide for insertion into and withdrawal of the core from the mold.

Abstract: An etching apparatus for the selective etching of e.g. single crystal silicon is described. The apparatus includes a tank for receiving a quantity of liquid etchant, the tank being provided with means for injecting oxygen, nitrogen or mixtures thereof into the etchant. Stirrers circulate the etchant around the bath. Gas injection has been found to improve the quality of the etched product and to provide control of the etching process.

Abstract: A device for interposing in a telephone service line for testing the service line and a telephone network attached to the service line. Included is a first circuit for testing the service line, a second circuit for testing the telephone network, a third circuit for providing a normal connected between the service line and the telephone network, a fourth circuit for generating a reset signal on the service line, and a fifth circuit for testing an individual handset. Connectors are provided for connecting the device in circuit between a telephone service line and a telephone network. A multiposition switch is included for switching between the first through fifth circuits.

Abstract: An improved decanter vessel formed of a rigid receptacle and a pouring spout unit permanently engaged about the neck of the receptacle. The pouring spout unit has formed therein an internal annular cavity shaped to accommodate the neck of the receptacle. The receptacle and pouring spout unit are joined by a flexible material which surrounds the neck portion of the receptacle forming a mechanical lock between the neck portion and the pouring spout unit. During assembly of the decanter, the flexible material is in a liquid state to facilitate joining of the receptacle and the pouring spout unit and assure that the material evenly and completely surrounds the neck and fills the annular cavity. The flexible material solidifies after assembly of the decanter vessel.

Abstract: A portable screed for working concrete and having an elongated screed plate which has a flat bottom bearing surface and a width sufficient to permit the screed to float on the concrete while the screed is being guided by an operator. For imparting uniform vibrations to the screed plate for tamping the concrete, the screed includes a stiffening brace extending substantially the length of the screed, a series of rigid, spaced cross supports secured to the brace, and a vibratory mechanism connected to vibrate the screed plate through the cross supports. A motor is mounted on the screed plate for operating the vibratory mechanism.

Abstract: Apparatus for producing a pulsed electron beam, particularly adapted for inspecting integrated circuits, includes a beam scanner (10) for causing a continuous electron beam to scan a circle, which beam may emerge from the second of three electrostatic lenses of an electron beam microscope. The beam then passes a deflecting means (12) on the circle for deflecting the beam in a radial direction at selected locations, before being collected by means (14) for collecting the electron pulses from alternate locations to provide a pulsed electron beam.

Abstract: A fibre optic gyroscope arrangement having a nulling feedback control loop, the gyroscope including means 40 for varying wavelength of the light source 41 for a predetermined period of time at switch-on of the gyroscope and means for subsequently operating the light source 41 at a fixed wavelength.

Abstract: An anti-resheathing device for preventing a needle sheath from re-engaging the hub of a needle after the sheath has been disengaged from the hub when the needle hub has been inserted in a needle retention socket. The sheath has a pre-determined exterior dimension in that portion of the sheath adjacent the needle retention socket. A wall extends outwardly from the socket toward the sheath, and has an interior dimension less than the exterior dimension of the sheath and is constructed of a displaceable material having a memory such that the wall is displaced to accommodate the sheath when the hub is inserted within the socket. When the sheath is then removed from the hub, the wall returns to a substantially undisplaced orientation and, due to the exterior dimension of the wall, prevents the sheath from being re-engaged on the hub.

Abstract: In the atomic absorption or atomic fluorescence spectroscopy the problem exists to compensate the background absorption. For this purpose a measuring light beam, which is passed through a sample space, is frequency modulated by using the Doppler effect. This is achieved in that devices for generating a rate of change of the optical path length passing between two points of this path of rays of the measuring light beam (12) are provided in the path of rays of the measuring light beam (12). Different constructional solutions herefor are described. The optical path length can be varied cyclically by movable mirrors. But it is also possible to arrange a crystal (132) in the path of rays, the refractive index of which can be varied cyclically by applying an electric voltage to the field plates. (134 and 146).

Abstract: A method of forming a metal mold or die from a model of the mold contours. A workpiece for the mold is coated with a material which is resistant to an acidic etchant, and is then immersed in the etchant and brought into contact with a template for the metal mold or dies. Those portions of the coating contacted by the template are displaced until the template contacts the surface of the workpiece. The template is then withdrawn to permit the echant to etch any portions of the workpiece exposed by displacement of the coating. The process is progressively repeated until the surface of the workpiece conforms to any contouring of the surface of the template.

Abstract: An optical fiber cable package has a kingwire and a plurality of acrylate primary coated optical fibers all embedded in a one-shot extrusion of low melting point plastic, e.g. Hytrel 40. The fibers have a zero angle of lay. The package is particularly but not exclusively suitable for use in an optical fiber submarine cable.

Abstract: A disposable protective gown and process for making the gown. The gown is composed of a body portion which extends over the shoulders of the wearer and which has a pair of sleeves which extend outwardly from opposite sides. Each sleeve is attached to the body portion over an angle of attachment greater than 180.degree. and less than 300.degree.. A thumb loop is formed at the end of each of the sleeves and is shaped to engage the saddle of the thumb of a wearer. In forming the gown, after the body portion has been cut and the sleeves formed, the sleeves are attached to the body portion by heat sealing half the sleeve, then rotating the sleeve so that a second portion of the sleeve is attached to the gown, with the total angle of attachment not exceeding 300.degree.. In order to prevent inadvertent sealing of both sides of a sleeve together, each sleeve includes a circumferential notch which extends for a length up to that comprising the portion of a the sleeve that is not attached to the body of the gown.

Abstract: An arrangement for ensuring contact between resistance paths comprises a base of electrically non-conductive and elastically deformable material such as rubber. To the base is applied an electrically conductive coating. The resistance path is pressed against this layer by means of a covering element, the base being subjected to preloading. In this way, the contact can be ensured between a potentiometer resistance with terminal connections and a plug, around which a short-circuit interval is provided.