Abstract:
In apparatus for sensing and controlling the deposition of a thin film on to a substrate (12) from a gas or vapour phase, the optical reflectance or transmittance is sensed, the resonant frequency of a crystal (14) also exposed to the deposition is sensed, and the quotient of the change in each signal over a predetermined time interval is determined. The deposition can be terminated at a suitable thickness, for example a reflectance or transmittance maximum or minimum. Instead of an optical property, the electrical resistivity of the film may be sensed and used in the same way.
Abstract:
A surface on which there is a regular periodic pattern, often a relief pattern (12), is deformed, and in-plane deformation is sensed by illuminating the deformed pattern with a beam (12) of coherent light so that light is reflected as one zero order beam and a plurality of diffracted beams, and combining two of the beams (16, 18) so that they interfere in a manner related to the deformation along the direction of intersection of the surface plane with the plane in which the two interfering beams lie. The magnitude and direction of in-plane deformation in one or more directions and the magnitude and direction of the maximum in-plane stress or strain, can be determined automatically.
Abstract:
In devices comprising closely spaced metallised regions deposited upon a dielectric substrate, in particular acoustic wave devices, electric fields may arise between the regions due to pyroelectric effects or acquired static charges during production or subsequently. These fields can cause damage by arcing or cracking of the substrate. The present method overcomes this problem by providing resistive links between such regions so that the fields do not arise. Preferably the links are of metallising formed simultaneously with the metallised regions. Application to a SAW convolver is described in which the links are strips of metallising (7, 8, 9).
Abstract:
A composite of a homo- or co-polyolefin having an average molecular weight greater than 200,000 with up to 80% by volume of a particulate inorganic solid for use in endoprosthesis.
Abstract:
Dispositif permettant la variation de la vitesse ou autres parametres de fonctionnement d'une machine electrique sans connexion au rotor. La machine est du type a induction ayant un enroulement en parties separees pour creer dans l'entrefer un flux mobile ayant differentes vitesses en modifiant l'intensite du courant dans une partie de l'enroulement. Dans un exemple, l'intensite du courant est modifiee par une impedance variable connectee a une partie de l'enroulement, l'autre partie etant connectee a une alimentation electrique. Un autre exemple, Fig. 6, illustre deux machines (NM1, NM2) disposees pour entrainer un vehicule a rail par l'intermediaire de roues a rail lisses fixees aux axes des rotors des machines. Un inverseur simple a frequence variable (NI) entraine les deux machines et est connecte a une piece (MP) de chaque enroulement de la machine. D'autres pieces (AP) de chaque enroulement des machines sont interconnectees par un dispositif de liaison (NC). En fonctionnement, la puissance (reelle ou reactive) est transferee entre les machines le long du dispositif de liaison pour egaliser le couple des machines. Ce dispositif permet d'eviter le depart d'une machine alors que l'autre cale.
Abstract:
Homo ou copolymeres d'un ester de (meth)acrylate dans lequel des atomes pouvant absorber des rayons X sont incorpores par liaison covalente, le polymere resultant ayant un poids moleculaire moyen de viscosite superieure a 400000.
Abstract:
A crop cutting and conditioning apparatus has two vertical axis rotary drum cutters (13), each having an upper rotor with a crop conveying surface (19) and a lower rotor carrying knives (21). Gears drive the upper and lower rotors at different peripheral velocities. The lower rotor has an annular rim (18) having an upper surface shaped to continue the outline of the conveying surface (19). The knives (21) protrude outwardly from beneath the rim (18) and rotate with the rim. The upper rotor has conditioning elements comprising brushes (35) (or sheets of plastics material), for conveying crop and conditioning crop by relative movement between the brushes and the crop. The outer tips of the brushes (35) (or the edges of the sheet or rib-like elements) lie along one or more helical or part helical paths around the rotor axis. Preferably the lower end of each helix leads during the rotation so as to exert a lifting action on crop engaged by the rotors.
Abstract:
Bone growth is inhibited or promoted by a control component which interacts in situ with bodily material to give an electrical and/or chemical effect and is non-toxically bio-degradable to limit the duration of the inhibition or promotion of bone growth. The control component is discrete from, attached to or integral with a structural component, especially and endoprosthetic component.
Abstract:
Surgical implants, especially endoprosthetic orthopaedic implants and sutures, are rendered antimicrobial by the presence of a bioerodible metallic silver component, especially a surface coating, which provides in vivo a sustained release of silver ions in a concentration sufficient to provide a localized antimicrobial effect but insufficient to cause significant damage to connective tissue. Latently bioerodible silver components of an implant can be activated by, for example, abrasion, heating to above about 180` or, especially, contact with hydrogen peroxide.
Abstract:
A method of sensing the optical deflection function of an approximately cylindrical object, such as an optical fibre preform, comprises illuminating the object with collimated light; focusing the transmitted light so that in the focal plane the distance of the light from the optical axis is linearly proportional to the angle through which light has been deviated by the object; optically modulating the focused light so that a property of the light varies as a function of said distance, and calculating the deflection function from the modulated light. The modulations may be spatial or temporal. The refractive index profile can also be calculated.