95results about How to "High mechanical quality factor" patented technology

The invention discloses a harmonic oscillator of a solid fluctuation gyro, which comprises a resonance ring (1), a resonance transmission part (2), a chassis (3) and a piezoelectric element (4), wherein, the resonance ring (1) is connected with the chassis (3) through the resonance transmission part (2), the resonance transmission part (2) is composed of support beams (21) which are uniformly distributed in the circumferential direction, and the piezoelectric element (4) is arranged on the support beams (21). The invention further discloses the solid fluctuation gyro provided with the harmonic oscillator. The solid fluctuation gyro and the harmonic oscillator of the invention have the advantages of high sensitivity, good sensing effect, convenient machining, low machining cost, simple mechanical balance procedure and the like.

The invention discloses a micromachine-based electromagnetic excitation resonant pressure sensor, and relates to a micromachine sensing technology. The sensor is provided with three groups of resonators which are clamped by anchor points on a pressure membrane, arranged on a diagonal line of a frame, and provided with electrodes. The resonators applied with excitation signals are excited by magnetic field force under the action of an external magnetic field; and when pressure to be tested is present outside, the pressure membrane generates strain, and the strain is transmitted to the resonators through the anchor points to change the rigidity of the resonators, so that the natural frequency of the resonators is changed, and the pressure to be tested outside can be measured by detecting the frequency of output signals of vibration pickup electrodes. The sensor has two packaging modes, and is subjected to stress isolation through a ceramic ring of which the coefficient of thermal expansion is basically same as monocrystalline silicon. The resonators of the sensor work in a horizontal vibration mode; the shift caused by external factors such as temperature and the like is inhibited through differential output, and the sensitivity is improved; and the resonators are released by a heavy boron-diffusion self-stop corrosion technology, a process is simple and the consistency is high.

The invention discloses a doped and modified lead zirconate-titanate piezoelectric ceramic and a preparation method thereof. The doped and modified lead zirconate-titanate piezoelectric ceramic is shown in a following chemical formula I, namely xPb(Mg1/3Nb2/3)O3-yPb(Ni1/3Nb2/3)O3-(1-x-y)Pb(Ti1/2Zr1/2)O3+lSrCO3+mZnO+nQ, wherein Q is at least selected from Li2CO3 (lithium carbonate), CuO (copper oxide), SiO2 (silicon dioxide), MnO2 (manganese dioxide), Bi2O3 (bismuth oxide) and La2O3 (lanthanum oxide); l, m and n are respectively the mass percentages of SrCO3 (strontium carbonate), ZnO (zinc oxide) and Q in the compound Pb(Mg1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-Pb(Ti1/2Zr1/2)O3; x is greater than or equal to 0.10 and is smaller than or equal to 0.70, y is greater than or equal to 0.08 and is smallerthan or equal to 0.38, l is greater than 0 and is smaller than or equal to 0.5, m is greater than 0 and is smaller than or equal to 0.50, and n is greater than or equal to 0 and is smaller than or equal to 0.5. The doped and modified lead zirconate-titanate piezoelectric ceramic has the excellent properties of low sintering temperature, high electromechanical coupling coefficient, high piezoelectric strain coefficient, small dielectric loss and the like.

There are provided a lead- and potassium-free piezoelectric material that has a high Curie temperature and a high mechanical quality factor and is stable in long-term driving and a piezoelectric element including the lead- and potassium-free piezoelectric material. A piezoelectric material containing a perovskite-type metal oxide having the general formula (1): Na_xBa_1-yNb_yZr_1-yO₃ wherein x satisfies 0.85≦x≦0.96 and y satisfies 0.90≦y≦0.96 and a piezoelectric element including the piezoelectric material. The piezoelectric material may include the perovskite-type metal oxide and Cu, and the Cu content corresponds to 2.00 mol % or less of the amount of the perovskite-type metal oxide.

A piezoelectric drive device includes a vibrating plate and multiple piezoelectric drive units that are disposed in the vibrating plate, and that respectively have a contact portion which can come into contact with a driven body.

The invention discloses a biaxially resonant silicon-micromachined accelerometer in the shape of a Chinese character 'tian' and aims at designing and manufacturing a high-sensitivity and high-resolution biaxially-resonant silicon-micromachined accelerometer. The structure is characterized in that (1) because a mass block structure in the shape of a Chinese character 'tian' is adopted, the volume of a mass block is maximized, and the acceleration can be converted into an inertial force more effectively; and the whole structure is symmetrically distributed, which is favorable for resisting noises and inhibiting temperature drift; (2) a support beam (in the shape of a Chinese character 'ji') arranged at the periphery of the structure facilitates the release of the residual stress and temperature stress of the structure, thereby reducing the support stiffness of the structure in a sensitive direction; (3) due to the application of a spring-like beam (in the shape of a Chinese character 'kou') at one end of a resonator, the influence of external shocks on the beam is reduced, and the spring-like beam plays a role in releasing the residual stress of the structure; and (4) an arc structure at the root part of a tuning fork in the resonator can be used for effectively reducing the energy coupling and improving the mechanical quality factor of the resonator, and is easy for realizationof closed-loop control.

A ceramic powder contains a metal oxide represented by the following general formula (1). The ceramic powder has a single perovskite-type crystal phase. The ceramic powder is composed of particles having an average equivalent circular diameter in the range of 100 nm or more and less than 1000 nm and has a ratio c₁/a₁ in the range of 1.000≦c₁/a₁≦1.010, wherein c₁ and a₁ denote the c-axis length and a-axis length, respectively, of unit cells of the perovskite-type metal oxide, c₁ being greater than or equal to a₁.

(Ba_1-xCa_x)_α(Ti_1-y-zZr_yMn_z)O₃(0.9900≦α≦1.0100, 0.125≦x≦0.300, 0.020≦y≦0.095, 0.003≦z≦0.016)

The use of bulk-solidifying amorphous metal alloys, frequently called “liquid metals”, are disclosed as a preferred material of construction for the manufacture of mechanical resonators, such as mechanical resonators utilized in the following: systems using tuning forks and variants of tuning forks, inertial microbalances, vibrating level detectors, vibrating viscosity and rheology measuring instruments, vibrating tube meters, such as Coriolis mass flow meters, vibrating structure gyroscopes, vortex flow meters, sonotrodes for various applications such as welding and medical applications, and piezoelectric activated mechanical resonators. A method of attaining high mechanical Q factors, sensitivity, elasticity, hardness, and high specific strength properties offered by the use of bulk-solidifying amorphous metal alloys in the manufacture of mechanical resonators is disclosed.

To provide a lead-free piezoelectric material having a high and stable piezoelectric constant in a wide operating temperature range. The piezoelectric material contains a perovskite type metal oxide having the general formula (1), Mn, Mg,

(Ba_1-xCa_x)_a(Ti_1-y-zSn_yZr_z)O₃  (1)

• • (wherein x is in the range of 0.050≦x≦0.200, y is in the range of 0.010≦y≦0.040, and z is in the range of 0≦z≦0.040, provided that x≧0.375(y+z)+0.050, and a is in the range of 0.9925+b≦a≦1.0025+b)
  • wherein the amount b (mol) of Mn on a metal basis per mole of the metal oxide is in the range of 0.0048≦b≦0.0400, and the Mg content on a metal basis per 100 parts by weight of the metal oxide is 0.100 parts by weight or less.

There is provided a lead-free piezoelectric material having a satisfactory piezoelectric constant and mechanical quality factor in the range of device operating temperatures (from −30° C. to 50° C.). The piezoelectric material contains a main constituent containing a perovskite-type metal oxide expressed by the general formula (Ba_1-xCa_x)_a(Ti_1-yZr_y)O₃, where x, y and a satisfy the 0.030≦x<0.090, 0.030≦y≦0.080, and 0.9860≦a≦1.0200. The material also contains 0.040 to 0.500 part by weight of Mn, 0.042 to 0.850 part by weight of Bi, 0 to 0.028 part by weight of Li, 0.001 to 4.000 part by weight of a third sub-constituent including at least one of Si and B, and 0.001 to 4.000 parts by weight of Cu, each in terms of element relative to 100 parts by weight of the metal oxide.

A mirror assembly comprising a carrier substrate; a stack comprising a plurality of alternating monocrystalline semiconductor layers of a first and a second type, wherein the layers of the first type have an index of refraction higher than the layers of the second type thereby forming a Bragg mirror; wherein the carrier substrate is curved having a radius of curvature between 0.1 m and 10 km; wherein the stack is attached to the curved carrier substrate.

Provided is a lead-free piezoelectric material having satisfactory piezoelectric constant and mechanical quality factor in a device driving temperature range (−30° C. to 50° C.) The piezoelectric material includes a main component containing a perovskite-type metal oxide represented by Formula 1, a first auxiliary component composed of Mn, and a second auxiliary component composed of Bi or Bi and Li. The content of Mn is 0.040 parts by weight or more and 0.500 parts by weight or less based on 100 parts by weight of the metal oxide on a metal basis. The content of Bi is 0.042 parts by weight or more and 0.850 parts by weight or less and the content of Li is 0.028 parts by weight or less (including 0 parts by weight) based on 100 parts by weight of the metal oxide on a metal basis.

(Ba_1-xCa_x)_a(Ti_1-yZr_y)O₃ . . . (1), wherein, 0.030≦x<0.090, 0.030≦y≦0.080, and 0.9860≦a≦1.0200.

The invention provides potassium-sodium niobate based leadless piezoelectric ceramic which has high mechanical quality factor and a preparation process of the piezoelectric ceramic. The chemical general formula of the piezoelectric ceramic is 0.956(0.988-x)(K<0.37>Na<0.63>)<0.86>Ca<0.04>Li<0.02>Nb<0.85>O<3>-0.044(0.988-x)K<0.85>Ti<0.85>Nb<1.15>O<5>-xBaSnO3-yMnO-zCeO, wherein 0.024 <= x <= 0.073, 0.005 <= y <= 0.09, 0.005 <= z <= 0.08, x, y and z being molar weight. The ceramic system is higher than 240 pC/N in piezoelectric constant, is more than 0.3 in planar electromechanical coupling factor, is not less than 2100 in dielectric constant, is lower than 0.02 in dielectric loss at room temperature under 1 kHz, and is not lower than 110 in mechanical quality factor.

The invention relates to a mass flow sensor. The mass flow sensor comprises a first measuring pipe and a second measuring pipe, wherein the two measuring pipes are identical in structure and size and are arranged in a shell in parallel, an angle formed between the axis of a straight pipe section of each measuring pipe and the axis of a first oblique pipe section and an angle formed between the axis of the first oblique pipe section and the axis of a first port section are respectively of an obtuse angle, and an angle formed between the axis of the straight pipe section and the axis of a second oblique pipe section and an angle formed between the axis of the second oblique pipe section and the axis of a second port section are respectively of an obtuse angle. By adopting the technical scheme, when the mass flow of compressed natural gas is measured, the resistance to the compressed natural gas can be reduced; moreover, the distance can be firmly controlled, and a compressed natural gas circulation measuring pipe is enabled to have a high mechanical quality factor, good stability and high shock resistance.