661results about How to "Raise the natural frequency" patented technology

An apparatus for varying the gain of a fiber optic sensor that non-intrusively senses the strain response of a pipe is provided. The apparatus includes a circumferential strain attenuator that has an annular land portion that mechanically couples the attenuator to the pipe. An annular web extends coaxially from the land portion and has a reduced cross sectional area relative to the land, and an annular mandrel portion extends coaxially from the web portion and forms a gap between the pipe and the mandrel. The fiber optic sensor is wound on the circumferential strain attenuator. The web and mandrel cooperate to reduce the strain response of the fiber optic sensor relative to the strain response of the pipe.

There is provided a golf club head that produces a loud hitting sound satisfying the golfer even if the volume of the golf club head having a hollow structure is increased to at least about 400 cc. A golf club head 1 having a hollow structure comprises a face part 2, a side part 3 comprising a back side, a sole part 4, a crown part 5, and a hosel part 9 having a shaft insertion hole, and the crown part 5. The crown part comprises a thick region 6 and a thin region 8. The thick region 6 extends through a distance W_A of at least about 20 mm from the center axis line C of the shaft insertion hole toward the highest point T of the crown part 5 and extends through a distance W_B of at least about 30 mm from the center axis line C of the shaft insertion hole toward the back side so that the crown part 5 has the first-order natural frequency of at least about 3000 Hz.

A blade for mounting in an annular array about a rotary hub, the blade having: a blade root; an airfoil profile with a concave pressure side surface; a chord line extending between a leading edge and a trailing edge; and a blade tip, where the blade has a recess in the pressure side surface with an outer periphery disposed radially inwardly from the blade tip, and inwardly along the chord line from the leading edge and from the trailing edge.

An apparatus or mounting an optical element in an optical system, in particular a mirror or a lens, in a projection exposure machine, in particular a projection lens in semiconductor lithography, is connected to an external base structure with the aid of at least three articulation sites that are arranged on the circumference of the optical element and at which a bearing device acts in each case, wherein the bearing device has at least one bending element, resembling a leaf spring, arranged tangentially to the optical element, and at least one bending element, resembling a leaf spring, arranged in the radial direction relative to the optical element.

A free space optical switch that uses both an open loop control mode and a closed loop control mode. The open loop control mode is used to transition to a state where at least some light is sensed at a destination port. A closed loop control mode is then used, whereby a series of controlled dither signals are adjusted for system dynamics. Modifying the dither signals in this matter allows moving actuators at a rate that is much closer to the natural frequency of the underlying system, and hence speeds up the system convergence process. Variable modulation amplitudes may be employed on the dither signals to maximize convergence speed. In particular, changes in the dither signal can be made in accordance with the change in amplitude as a function of a gradient along a parabola that models the optical system response. According to still further aspects, the dither signals may be compensated for a desired and selectable attenuation level of output optical power.

The invention discloses a method for testing and analyzing frictional noise and a test device for the method. The method comprises that: a lower fixture clamping a lower friction part is fixed onto a reciprocating device; an upper fixture clamping an upper friction part penetrates through a horizontal support to contact with the bottom of a strain force sensor; a three-dimensional acceleration sensor is mounted on the upper fixture; two ends of the horizontal support are fixed onto support bases by piezoelectric force sensors; and the strain force sensor is fixed to the bottom of a two-dimensional moving table. A sensing end of an acoustic sensor is close to a contact interface of the upper friction part and the lower friction part, and the two-dimensional moving table is controlled so that the upper friction part and the lower friction part are controlled to do reciprocating friction motion, and the three sensors accurately, synchronously and dynamically acquire the frictional noise,vibration acceleration and frictional force and analyze the frictional noise, the vibration acceleration and the frictional force in real time. Therefore, mutual relation and influencing law of the frictional noise, the interface and characteristics of a system are accurately analyzed, a mechanism of production of the frictional noise is disclosed, and a more accurate and reliable test basis is provided for realizing noise-reduction design for mechanical equipment, improving performance of the mechanical equipment and prolonging the service life of the mechanical equipment.

A fuel-cell compressed-air supplying device 6 includes a centrifugal compressor 12 provided in a casing 11, and a bearing device 14 for supporting a rotation shaft 13 of the compressor 12. The bearing device 14 includes a pair of radial foil bearings 21 and 22 provided coaxially with the rotation shaft 13 for supporting the rotation shaft 13 in the radial direction, and an axial magnetic bearing 23 facing to the rotation shaft 13 in the axial direction for supporting the rotation shaft 13 in the axial direction. Axial electromagnets 24 and 25 of the axial magnetic bearing 23 are integrated with the radial foil bearings 21 and 22, respectively.

The invention discloses a construction method for reinforcing and repairing an integral wall of ancient architecture. The construction method comprises the steps of site survey and work preparation, wall foundation reinforcement, wall surface treatment, wall reinforcement and wall maintenance. The construction method is simple and easy to implement, scientific and convenient, and has the advantages of fast construction progress, low construction cost, high working efficiency and wide application range. According to the principle of 'repairing the old as the old', the cultural relic value of ancient architectural elements is kept, only damaged parts are repaired and reinforced, and the whole wall does not need to be replaced. The ancient architecture wall is priceless in cultural relic value. By using the method, original parts can be kept when the ancient architecture wall is damaged and loses bearing capacity, and a bearing function is recovered; the method conforms to the principle of 'repairing the old as the old', and is of great significance to the protection of the national cultural relics.

This invention relates to an apparatus for making highly sensitive differential measurements of acceleration. The vibration sensor includes the use of moveable gate field effect transistors to sense the motion of a cantilever beam relative to the motion sensed by a reference structure, it also includes an actuator element formed by a pair of electrodes actuating electrostatically on the beam. A feedback control loop is also included for force balance operation resulting in a very wide dynamic range for the sensor.

The invention relates to a beam and groove combined stepped island film micropressure sensor chip and a manufacturing method thereof. The chip comprises a thin film in the middle of a substrate, four shallow grooves are formed along the edges of the upper portion of the thin film, four embossment beams are arranged between the ends of the adjacent shallow grooves and connected with the substrate, and the upper surfaces of the embossment beams, the upper surface of the thin film and the bottom faces of the shallow grooves form a beam and groove combined stepped thin film structure; four piezoresistor strips are arranged on the four embossment beams and connected through metal leads into semi-open-loop Wheatstone bridges, and the output ends of the bridges are connected with bonding pads; four bumps are evenly distributed along the edges of the lower portion of the thin film and connected with the substrate; four mass blocks are spaced from the bumps, and the bumps are connected to the thin film. The manufacturing method includes the steps that the piezoresistor strips are made of SOI silicon wafers in an oxidized mode at high temperature, and an Ohmic contact region is obtained to manufacture the metal leads and the bonding pads; then the four embossment beams and the shallow grooves are manufactured, and the back face of the substrate and anti-overload glass are bonded. The beam and groove combined stepped island film micropressure sensor chip has the advantages of being high in sensitivity and linearity and the like.

The invention discloses an annular permanent magnet low frequency vibration isolation mechanism based on a negative stiffness theory. The mechanism comprises an upper rubber sheet, an inner annular permanent magnet fixing mandrel, an upper rubber sheet upper pressing ring, an upper rubber sheet outer pressing ring, an outer annular permanent magnet, a lower rubber sheet, a lower rubber sheet inner pressing sheet, a lower rubber sheet outer pressing ring, an outer annular permanent magnet fixing sleeve and an inner annular permanent magnet, wherein the inner annular permanent magnet is magnetized axially; the outer annular permanent magnet is radially magnetized; a positive stiffness system consists of the inner annular permanent magnet and the outer annular permanent magnet; a negative stiffness system consists of the upper rubber sheet and the lower rubber sheet; and the positive stiffness system and the negative stiffness system are used in parallel to form the low frequency vibration isolation mechanism. Three or four single-degree-of-freedom vibration isolation mechanisms are used in parallel to realize three-degree-of-freedom low frequency vibration isolation. When the vibration isolation mechanism has the largest magnetic force, the stiffness of the vibration isolation mechanism approximates to zero. Without an outside air source, the vibration isolation mechanism has a prospect of being used in vacuum, has the characteristics of simple structure and low cost, is easy to process, and can be applied to the fields of optics, acoustics, biologics, semiconductor manufacturing, precise measurement and the like.

The invention discloses a small-size speed change control moment gyroscope, and belongs to the technical field of control moment gyroscopes. The small-size speed change control moment gyroscope comprises a high-speed component, a connection bracket and a low-speed component, wherein the high-speed component supplies constant angular momentum in a control moment gyroscope mode and outputs fine moment required by whole satellite attitude control in a flywheel mode; the connection bracket is connected with the high-speed component and the low-speed component and guarantees the orthogonal perpendicularity between the angular momentum direction and the axial direction of a framework; the low-speed component supports the high-speed component and the connection bracket and supplies a mounting interface for a whole satellite; in the control moment gyroscope mode, large moment which is required by fastmoving of the whole satellite and is also orthogonal to the angular momentum direction and the axial direction of the framework is generated; in the flywheel mode, the fine moment output by the high-speed component is transmitted to the whole satellite for the attitude control. The speed change control moment gyroscope disclosed by the invention realizes the high-precision framework locking, the minimization, the light weight and the high rigidity, and is suitable for the application to small quick satellites.

A transducer of pressure , flow speed and flow direction at deep sea features having column formed seat and its ring shell , setting elastic beam support used as strain plate carrier between seat and shell , setting four said beams on one plane vertical to seat axis and arranging them two by two symmetrically in cross based on seat axis , using top and bottom end covers as well as bellows to form closed oil cavity , using strain plate to output collected signal and solid connecting gyro-rotor with seat axis as rotation centre at centre of top end cover.

A test assembly for a disk drive suspension head gimbal assembly includes a steel mount plate and a mount sub-plate of a material such as silicon carbide having a modulus of elasticity to density ratio that is significantly higher than the ratio for stainless steel. Preferably the mount plate and the mount sub-plate taken together have a first resonant shear frequency of greater than 50 KHz, which is generally greater than the frequency range of interest for testing head gimbal assemblies. The high modulus of elasticity to density ratio helps to ensure that any shear mode resonances of the test assembly occur at frequencies that are higher than the frequencies of interesting for head gimbal assembly shear resonance testing purposes.

The invention discloses an improved wind load pressure sensor, comprising a sensor shell, an oil charge sensitive body and a signal conditioning circuit, wherein, the oil charge sensitive body is composed of a sensitivity body shell in the form of a groove, a silicon integrated sensitive chip and an elastic separation film fixed on the opening of the groove, the ring circumambience of the back pressure face of the silicon integrated sensitive chip is fixed at the bottom of the groove through a fixed supporting ring in a sealing manner, the back pressure face of the silicon integrated sensitive chip is communicated with ambient pressure through a back pressure airway tube, the pressure surface of the silicon integrated sensitive chip is provided with a Wheatstone bridge on which a strain resistor is led to the signal conditioning circuit through an internal lead and a lead column and then is output, the non-pressure surface of the silicon integrated sensitive chip is provided with a temperature sensor, a heating resistor and a constant temperature control circuit controlling the heating resistor according to the temperature sensor, and silicon oil is filled among the elastic separation film, a groove internal ring surface and the pressure surface of the silicon integrated sensitive chip. The invention can control the temperature of the oil charge sensitive body, and eliminate the problem that an oil charge micro-pressure sensor is in fault due to the influence of ambient temperature, thereby realizing high-accuracy survey of wind loads.

Provided is a pre-tensioned prestressed composite beam, which is an I-shaped beam composed of H-shaped steel and concrete, the web plate of the H-shaped steel is provided with trapezoidal holes (14) at intervals, the upper flange and the lower flange of the H-shaped steel are welded with shearing nails, the outer periphery of the lower flange is enclosed with concrete to form a steel-concrete lower flange (4), and the inside of the steel-concrete lower flange is embedded with prestressed steel twisted wire by pretensioning method. The manufacturing method of the composite beam is that: a steel plate is cut into two tooth-shaped plates along tooth-shaped line to be respectively as the trapezoidal hole plates of the H-shaped steel flange, the trapezoidal hole plates are welded with steel plates to form the web plate, the web plate is welded with the upper flange and the lower flange to form the H-shaped steel (1) having trapezoidal holes, the H-shaped steel is put on a base surface with the lower flange downward, the two sides of the lower flange are provided with side molds, a stirrup (7) is arranged and steel twisted wires (3) are longitudinally fastened between the two side molds, the steel twisted wire is tensioned to tensioning state, the concrete for enclosing the H-shaped lower flange is poured and tamped between the two side molds, the steel-concrete lower flange (4) is formed after demolding, and the steel twisted wire at tensioning state is loosened after the concrete reached to predetermined strength and is cut off at predetermined position. The invention is suitable for beams of buildings.

The invention belongs to the technical field of mechanical dynamics, and relates to a determination method for the inherent frequency of a rotor-blade coupled system. The determination method saves the cost of a sensor, an amplifier and a display or record instrument needed by experimental tests and can obtain the higher-order inherent frequency and the inherent frequency in a rotating state. The inherent frequency of the rotor-blade coupled system can be obtained just by modifying the structural size of the system without repeated modeling, the bending and torsion influence on a complex stepped rotating shaft of the coupled system, the gyroscopic effect of a shaft and a disc, centrifugal rigidifying, rotary softening and the Coriolis force influence on blades are considered so that a more accurate result can be obtained; in addition, imbalance responses, blade tip rub-impact and other faults of the rotor-blade coupled system can be analyzed, so that the system structure is optimized.