143 results about "Resonance effect" patented technology

The invention discloses a spiral resonance photoacoustic cell and an operation method, the spiral resonance photoacoustic cell comprises a gas chamber straight tube, a spiral tube, an optical fiber collimator and an optical fiber F-P sonic sensor, the two ends of the gas chamber straight tube are open, the two ends of the spiral tube are communicated with the gas chamber straight tube, an acoustic resonance point is formed at the center of the spiral tube, and the optical fiber F-P sonic sensor is arranged in the central area of the spiral tube; and the optical fiber collimator is arranged at one end of the air chamber straight pipe. The spiral pipe is wound outside the air chamber straight pipe, the spiral pipe is communicated with the air chamber straight pipe, the structural design of the spiral pipe enables the spiral pipe to form acoustic resonance at a specific frequency, and the optical fiber F-P sonic sensor obtains a photoacoustic signal; compared with a conventional resonance photoacoustic cell, the physical volume of the resonance photoacoustic cell is greatly compressed, and the system integration level is effectively improved. More importantly, under the condition that a compact appearance similar to that of a non-resonant photoacoustic cell is kept, the device amplifies the photoacoustic signal intensity by several times through an acoustic resonance effect, and the detection sensitivity and the signal-to-noise ratio of the system are remarkably improved.

The invention discloses an acoustic black hole structure and a vibration damping device.The acoustic black hole structure comprises an acoustic black hole body and a damping layer, the acoustic black hole body is provided with a uniform thickness area and an acoustic black hole area, the acoustic black hole area is provided with a plurality of grooves, the grooves are distributed from the first end to the second end of the acoustic black hole area, and the damping layer is arranged between the first end and the second end of the acoustic black hole area. The depths of the grooves are gradually increased in the direction from the first end to the second end, and the damping layer is arranged in the acoustic black hole area. By machining the groove in the acoustic black hole area, the local bending rigidity of the acoustic black hole body is changed, the bending wave speed of the acoustic black hole body is reduced, the acoustic black hole effect is achieved, due to the arrangement of the groove, the local resonance effect can be utilized, and then structural vibration suppression in the low-frequency range is achieved; the problem that a traditional acoustic black hole structure is poor in low-frequency-band vibration reduction effect is solved, in addition, thickness cutting of an acoustic black hole area of an original structure is avoided, and the manufacturing difficulty and the requirement for the precision of machining equipment are lowered.

The invention relates to the technical field of resonant pouring castings, in particular to a method for improving the homogeneity of castings in all directions based on resonant pouring, which comprises the following steps: preparing a mold / casting mold, setting resonant parameters, pouring molten metal, maintaining resonance and solidifying, and detecting the homogeneity. Through the resonance effect, molten metal mold filling is uniform, the size qualification rate is increased, meanwhile, grain refinement can be promoted, the isotropic performance uniformity and stability of a casting are remarkably improved, the internal defect rate is greatly reduced, the comprehensive yield is increased, and energy consumption and cost are reduced.

The invention relates to the technical field of diaphragm pump aging test, and discloses a two-parameter intelligent closed-loop diaphragm pump aging test system and method. According to the method, a temperature spectrum and a vibration spectrum are obtained through fast Fourier transform, a frequency domain coherence coefficient is calculated to identify temperature-vibration coupling characteristics, a resonance frequency band and a drift trend thereof are identified in real time by adopting a spectrum peak tracking algorithm, and a multi-objective optimization function considering aging acceleration efficiency and resonance risk is constructed. And solving the optimal temperature stress amplitude and vibration stress frequency by using a particle swarm algorithm, generating a stress loading instruction avoiding a resonance area through a self-adaptive PID controller, and dynamically updating model parameters based on a closed-loop feedback mechanism. According to the invention, the problem of resonance effect amplification caused by traditional fixed frequency stress loading is solved, and refined adaptive stress control is realized.

The invention belongs to the technical field of SERS (Surface Enhanced Raman Scattering) detection, and relates to a preparation method of an Ag-Fe3O4 composite SERS substrate and application of the Ag-Fe3O4 composite SERS substrate in monitoring trace pollutants in water. Based on a plasma-semiconductor synergistic enhancement mechanism, cubic Fe3O4 nano particles with exposed {100} crystal faces are synthesized through a hydrothermal method, and the cubic Fe3O4 nano particles and Ag nano particles are subjected to ultrasonic-stirring to construct the Schottky heterojunction. The substrate creatively realizes dual-channel enhancement: the local surface plasmon resonance effect of Ag nanoparticles generates electromagnetic enhancement, the narrow band gap of Fe3O4 promotes photo-induced electrons to be transferred to Ag, an interface electric field is formed, and the polarizability of adsorption molecules is remarkably increased. When the probe is applied to detection of trace pollutants in a water body, the probe molecule RB is anchored on the surface of Fe3O4 through carboxyl, and the HOMO energy level of the probe molecule RB and the valence band top of Fe3O4 generate resonance charge transfer, so that the Raman cross section is improved. The detection limit of RB under 0.25 mW laser is increased by several orders of magnitude compared with that of a single Ag substrate.

The invention discloses a double-cantilever-beam piezoelectric vibration energy collector based on an annular steady state, which comprises a piezoelectric transducer, an elastic cantilever beam, a magnet and a base, after the piezoelectric transducer is mounted on the elastic cantilever beam to form a double-layer composite cantilever beam, the magnet is mounted at the free end of the double-layer composite cantilever beam, nonlinear coupling is carried out through repulsive magnetic force, and the piezoelectric transducer is connected with the base. The two-dimensional annular potential well structure with the adjustable potential well is formed, and the energy collector can easily trigger large-amplitude inter-well movement through the potential well structure. Through the nonlinear coupling induced internal resonance effect, inter-well energy transfer and two-dimensional potential well modulation are realized, and vibration energy can be efficiently captured in a broadband without a large amount of energy input or a complex structure. According to the design, the collection efficiency of low-frequency, low-intensity and multi-direction environment vibration energy in a wide working bandwidth is good.

The invention relates to the technical field of hyperbaric oxygen physiotherapy cabins, in particular to a terahertz wave micro hyperbaric oxygen physiotherapy cabin which comprises a cabin body, a door opening is formed in one face of the cabin body, a cabin top is installed at the top of the cabin body, and a door plate is hinged to the interior of the door opening through a hinge; the deep sea volcanic energy stone treatment device comprises a cabin, two groups of bed bodies are arranged in the cabin, the two groups of bed bodies are symmetrically mounted in the cabin, each bed body is of a hollow structure, and a plurality of terahertz wave generation modules are uniformly laid on the upper surface of each bed body through a support. The pelelith-based passive terahertz releaser formed after the pelelith-based passive terahertz releaser is combined with the ceramic matrix can continuously release terahertz waves with the frequency band of 0.1-12 THz, the vibration frequency is consistent with that of human cells, and the terahertz waves with the frequency band can repair biological enzyme and nucleic acid structure deformation caused by free radical attack and age increase through the biological resonance effect, so that the pelelith-based passive terahertz releaser can be used for repairing biological enzyme and nucleic acid structure deformation caused by free radical attack and age increase. The metabolic function is recovered from the cell molecule level, and the defect that a traditional oxygen cabin can only supply oxygen on the surface layer and cannot be deeply repaired is overcome.

The invention discloses a feedback control system of an ultrasonic flaw detector, and relates to the technical field of ultrasonic nondestructive detection.The system comprises a double-frequency transmitting module, a dynamic power control module, a signal acquisition module, a signal processing module and a feedback control module.The control system of the ultrasonic flaw detector adopts a double-frequency differential resonance detection method; two kinds of ultrasonic waves with specific frequency difference are emitted, the resonance effect at the defect is utilized to enhance echo signal characteristics, a double-frequency difference algorithm is matched, frequency deviation and amplitude change information of the defect can be accurately extracted, different types of defects can be effectively distinguished, and meanwhile, a dynamic power control mechanism can be used for controlling the detection accuracy according to the thickness, the structure and the material parameters of a detected object. The transmitting power of the double-frequency ultrasonic waves is adjusted in real time, it is ensured that the ultrasonic waves can reach the defect position in the optimal energy state under different working conditions, the resonance effect is enhanced, and therefore the system can achieve high-precision detection on tiny defects.

The invention provides a tunnel micro-seismic blasting targeted protection control method and device, and relates to the technical field of tunnel blasting, and the method comprises the steps: obtaining the distance between a protected building and a tunnel, and building a blasting vibration wave propagation model based on the distance and an initial attenuation coefficient; calculating predicted vibration data of seismic waves generated by each blasting section in a preset blasting scheme, wherein the seismic waves are transmitted to the protected building; taking the minimum theoretical peak vibration velocity of the protected building as a target, and calculating by adopting a numerical optimization algorithm to obtain a non-equal-difference detonation delay sequence of each blasting section; when the detonating time interval of the adjacent detonating sections is not equal to the integral multiple of the inherent main earthquake period, detonating is carried out according to the non-equal-difference detonating delay sequence; and comparing the actually measured vibration data with the predicted vibration data, and adjusting the attenuation coefficient based on the comparison result, thereby effectively preventing the resonance effect, preventing the vibration energy from being amplified, and ensuring the construction safety.

The embodiment of the invention relates to the technical field of devices for preventing or reducing noise, in particular to a rubber cell element structure and a vibration reduction and sound insulation assembly. According to the rubber cell element structure provided by the invention, due to the fact that the resonant frequencies of the cell element rings with different sizes are different, each first cell element ring is arranged in each second cell element ring, and the first cell element rings and the second cell element rings are concentrically arranged, so that vibration and noise reduction of noise with different frequencies are realized; a plurality of first cell element rings and a plurality of second cell element rings are arranged on a substrate, the substrate is supported by the cell element rings, the second cell element rings are arranged adjacent to one another, the cell element rings are arranged in a limited space as many as possible, and therefore the supporting performance of the substrate is improved; the first cell element ring and the second cell element ring are arranged to be of a structure capable of generating the local resonance effect to form the band gap, so that transmission of vibration noise in the structure is restrained, the restraining capacity of the structure for multi-band noise is improved, and the treatment requirement for different-frequency noise is comprehensively met.

The application belongs to the technical field of kitchen appliances, and particularly relates to a control method and device of an extractor hood and electronic equipment. The first offset displacement and the first vibration acceleration of a motor of the extractor hood are acquired, the vibration level of the motor is determined according to the first offset displacement and the first vibration acceleration, and the rotating speed of the motor of the extractor hood is adjusted according to the vibration level. The rotating speed of the motor is actively reduced, noise is avoided, vibration is inhibited, the abrasion and resonance effect of mechanical components are reduced, and the risk of structure loosening or part falling of the extractor hood caused by vibration is reduced.

This document discloses a medical system including a memory (110) storing machine-executable instructions (120) and a trained neural network (122). The trained neural network is configured to output rectified magnetic resonance image data (130) in response to receiving a set of magnetic resonance images (126) as input, each of the magnetic resonance images in the set having a different spatially constant frequency deviation resonance factor. The medical system also includes a computing system (106) configured to control the medical system, wherein the execution of the machine-executable instructions causes the computing system to: receive (200) k-space data (124) acquired according to a magnetic resonance imaging protocol; reconstruct (202) a set of magnetic resonance images (126) according to the magnetic resonance imaging protocol, wherein each of the magnetic resonance images in the set of magnetic resonance images is reconstructed assuming different spatially constant frequency deviation resonance factors selected from a list of frequency deviation resonance factors (128); and receive (204) rectified magnetic resonance image data in response to inputting the set of magnetic resonance images into the trained neural network.

The present invention refers to a type of reactor for initiating and carrying out a nuclear fusion reaction, use of plasmonic material in initiating a nuclear fusion reaction, and a method for initiating a nuclear fusion reaction. By using a plasmonic material to affect resonance effect, preferably plasmonic enhancement effect, a Coulomb explosion can be triggered, and in turn a nuclear fusion reaction can be initiated.

A cement scale removing system based on the resonance effect comprises a composite vibration generating device, a vibration feedback control system and an adjustable fixing device, the composite vibration generating device is composed of a pneumatic vibration device and an ultrasonic vibration device, and the pneumatic vibration device and the ultrasonic vibration device are alternately installed on the adjustable fixing device; the device has the following beneficial effects that broadband vibration is generated through the composite vibration device, namely in a pneumatic-ultrasonic composite vibration mode, when the vibration frequency is matched with the inherent frequency of a scaling layer, the resonance effect is generated, the energy transmission efficiency is greatly improved, internal cracks of scaling are expanded, efficient descaling is achieved, the device can adapt to structures of different thicknesses, and the device is suitable for large-scale popularization and application. The long-standing problem of contradiction between descaling efficiency and energy consumption in the prior art is solved.

The utility model discloses a noise reduction box and a traction machine, which belong to the technical field of traction machines, the noise reduction box comprises a first plate, a second plate and four third plates, the first ends of the four third plates are all installed on the first plate, the second ends of the four third plates are all installed on the second plate, the first plate and the second plate are arranged oppositely, and the first plate and the second plate are arranged oppositely. A cavity is formed among the inner sides of the first plate, the second plate and the four third plates; the first plate or the second plate is provided with a plurality of first ribs and second ribs, the first ribs extend in the width direction of the first plate or the second plate, and the second ribs extend in the length direction of the first plate or the second plate; the first ribs and the second ribs are distributed in a criss-cross mode, and a plurality of silencing areas are formed. The multiple silencing areas are used for conducting isolation and differentiation treatment on sound waves of the noise reduction box, the sound waves of the noise reduction box are prevented from being overlapped, the multiple silencing areas can prevent the sound waves from generating a resonance effect, and therefore 5%-15% of noise of a noise source can be reduced.

The application discloses a sound-absorbing metamaterial unit and device based on a coupling resonance structure and a broadband impedance modulation body. The sound-absorbing metamaterial unit comprises the coupling resonance structure and the broadband impedance modulation body. A top plate with holes and a surrounding wall and a bottom plate form the coupling resonance structure with a low-frequency resonance effect. Meanwhile, the broadband impedance modulation body in an acoustic waveguide cavity can adjust the characteristic impedance in a wide range. Due to the synergistic effect of the coupling resonance structure and the broadband impedance modulation body, impedance matching can be achieved in a low-frequency broadband range. The sound-absorbing metamaterial unit provided by the application can have good sound-absorbing effect in a low-frequency broadband range, and has the advantages of simple processing and manufacturing, low cost and high reliability. The sound-absorbing metamaterial unit overcomes the defects of a narrow sound-absorbing frequency band, a complex topological configuration and poor reliability of a traditional acoustic metamaterial sound-absorbing structure.

The invention belongs to the field of field conductance meters, and provides a variable-frequency multipurpose biological resonance field conductance meter which comprises a field conductance meter body, a power adapter and an activation water cup, the activation water cup comprises a cup body, a water outlet nozzle is arranged on the side face of the top of the cup body, a cup cover is arranged on the top of the cup body, and a cup handle is arranged on the side face of the cup body; a water circulation assembly is installed on the cup body, the two ends of the water circulation assembly are both communicated with the interior of the cup body, and the water circulation assembly is used for pumping water at the bottom of the cup body to the top of the cup body. According to the water cup, the water circulation assembly is arranged and can pump water at the bottom of the cup body to the top of the cup body, so that the water circularly flows up and down, the water at each position can be subjected to the resonance effect of a magnetic field with the same intensity, and the use effect of the product is improved.

The application relates to the technical field of motion regulation and driving, in particular to a reciprocating motion amplification device and method of a flexible structure of a swing bridge. The reciprocating motion amplification device comprises a loading unit, an excitation execution unit, a self-adaptive identification unit and an energy supply unit. The excitation execution unit and the self-adaptive identification unit are both installed in the loading unit. The self-adaptive identification unit collects vibration response signals of the flexible target structure in real time and identifies the real-time natural frequency, controls the excitation execution unit to adjust the excitation frequency, so that the excitation frequency is automatically matched with the real-time natural frequency, resonance effect is excited, and reciprocating motion amplification is realized. Through closed-loop self-adaptive control, frequency drift is automatically tracked without manual intervention, excitation power consumption is reduced while the significant amplification effect is maintained, and the system adaptability and intelligent level are improved.

The invention belongs to the technical field of energetic material preparation, and particularly relates to a method for preparing nano explosive particles based on an acoustic resonance assisted ball milling technology. Comprising the following steps: weighing and measuring acoustic resonance materials; refining explosive particles through acoustic resonance high-frequency vibration; filtering and drying the nano explosive particles; acoustic resonance high-frequency vibration is applied to the refining process of explosive particles, zirconium oxide beads in a ball milling tank collide at a fixed same frequency under the action of same-frequency resonance, so that an efficient and stable working space is formed in a limited space of the ball milling tank, the explosive particles flow among the zirconium oxide beads through ball milling liquid, and the explosive particles are refined. And under the impact and resonance effects of the zirconium oxide beads, the explosive particles are crushed and refined, and finally the nano explosive particles are prepared. According to the invention, the acoustic resonance frequency is highly matched with the characteristics of the zirconia beads, so that a better synergistic effect can be generated, and the nanocrystallization degree of explosive particles is improved; in addition, the application range of the acoustic resonance technology is expanded through the refinement principle.

The application provides a heterocyclic compound containing boron and nitrogen and an application thereof, and a structure general formula thereof is shown in the following formula (a), formula (b), formula (c) or formula (d): wherein, X1-X 16 are independently selected from CR0 or N atom, and at least one is N atom; Y and Z are independently selected from O, S, Se, CR1R2 or NR3; Ar1, Ar2 and Ar3 are independently selected from hydrogen, alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl. The heterocyclic compound of the application realizes multiple resonance effects by constructing N-B-N, O-B-N, S-B-N, Se-B-N and C-B-N between the donor and the acceptor at specific positions of the polycyclic aromatic compound skeleton, so that the emission spectrum is narrowed, the color purity is higher, and a high-efficiency MR-TAD device can be prepared.

The application discloses an organic light-emitting material with chiral and narrow-band emission performance, a preparation method and application thereof, and the core is that multiple resonance structures can effectively inhibit the vibration coupling between S1-S0 transition and excited state structure relaxation, form significant narrow-band emission, and simultaneously utilize the axial chirality characteristics of BINOL, utilize a chiral disturbance strategy to form circularly polarized luminescence. The application further provides a preparation method of the material, wherein compound B is obtained by reacting compound C with compound D, and the organic light-emitting material is obtained by reacting compound A with compound B. The material has the characteristics of thermal activated delayed fluorescence induced by multiple resonance effect, and simultaneously has the characteristics of circularly polarized luminescence, and can be applied to the fields of 3D display, molecular probe, spin information, optical data storage and processing and optoelectronic devices, and the like. The synthesis process is simple, raw materials are widely sourced and inexpensive, and the material is suitable for wide application.

The application discloses a loudspeaker assembly and belongs to the technical field of electroacoustics. The loudspeaker assembly comprises a mounting shell, a resonance tube and an exciter. The resonance tube is arranged in a containing cavity in the mounting shell and is in communication with a first opening in the mounting shell, and the first opening is in communication with the external environment. A second opening in the side of the exciter is in communication with the resonance tube through a mounting hole and the containing cavity. In this way, when the exciter reciprocates at the mounting hole, the air in the containing cavity can be vibrated, the vibrating air is continuously discharged from the containing cavity to the external environment through the resonance tube and the first opening, and the air in the external environment is continuously sucked into the containing cavity through the first opening and the resonance tube. The air in the containing cavity in the mounting shell produces a resonance effect at a specific frequency, and the resonance effect can compensate for the response attenuation between the modal vibration frequency points of the sound-emitting flat plate at a low frequency band (i.e., the response between the modal vibration frequency points of the sound-emitting flat plate is smoother).

A method for predicting electromagnetic performance of a three-dimensional structure unit cell configuration and an impedance matching design method, the prediction method comprising: experimentally measuring the basic electromagnetic parameters of the lossy material used in the three-dimensional structure unit cell configuration, assuming that the lossy material is an isotropic medium, and calculating the equivalent electromagnetic parameters of each layer of the configuration according to the duty cycle; calculating the fractal dimension of the whole three-dimensional structure unit cell configuration and determining the duty cycle and thickness of each layer of the three-dimensional structure unit cell configuration; constructing a structure resonance effect factor by using the basic electromagnetic parameters of the lossy material, the fractal dimension and the duty cycle, and then correcting the impedance gradient correction coefficient; and establishing a model equation of the macroscopic equivalent physical characteristic parameters of the structure interface, and calculating the interface wave impedance and surface reflectivity of the three-dimensional structure unit cell configuration by using the model equation. The theoretical and simulation calculation absorption peak frequency points are basically consistent, the macroscopic equivalent calculation method can accurately predict the absorption peak frequency point position, and the effectiveness of the calculation method is illustrated.

The application discloses a grating sensor for photoacoustic imaging, a photoacoustic probe and a photoacoustic imaging device, and the grating structure is processed by adopting a three-dimensional photoetching process, the design of the external solid structure and the internal periodic structure is combined, the external solid structure and the multiple cavity regions form a significant refractive index difference, and therefore the resonance effect of the grating is enhanced. In the ultrasonic detection process, the periodic resonance effect caused by the refractive index difference of the grating structure can efficiently convert the ultrasonic wave pressure into a light signal and further convert the light signal into an electric signal for photoacoustic imaging. Compared with the conventional ultrasonic sensor, the application provides higher sensitivity and a wider bandwidth, can realize clearer and more accurate imaging effect in high-resolution imaging, and effectively avoids the phenomenon that the ultrasonic sensor in the prior art has poor imaging effect in high-resolution imaging. In addition, the two-photon processing and ultraviolet light curing are adopted to form a significant refractive index difference, and therefore the acoustic spectrum detection capability of photoacoustic endoscopic imaging is improved.

The invention, which relates to the technical field of the hollow-core optical fiber, provides a hollow-core optical fiber with an anti-resonance layer having a multi-layer opening structure, comprising an outer cladding sleeve, an anti-resonance area and a hollow-core fiber core area enclosed by the anti-resonance area. The anti-resonance area comprises a plurality of anti-resonance units, each anti-resonance unit comprises at least one anti-resonance layer of an opening structure, and the edges of the two sides of an opening of each anti-resonance layer are connected with the inner wall of the outer cladding sleeve through two parallel thin walls. The optical fiber has the beneficial effects that multiple anti-resonance effects are generated through the opening anti-resonance layer, so that a light field is prevented from leaking to the cladding from the fiber core, and the light field is effectively limited in the hollow fiber core area for transmission; each anti-resonance layer is indirectly connected with the inner wall of the outer sleeve through a parallel thin wall, so that a connection node is far away from the fiber core, node coupling is reduced, and leakage of a light field to the cladding is weakened. The anti-resonance layer and the sleeve form a closed cavity, so that a high-refractive-index area is compared with a low-refractive-index medium in the cavity, a specific wavelength is reflected, a light field is prevented from being coupled with a cladding mode, and the light limiting capability is enhanced.

The invention belongs to the field of optical fiber sensing, and provides a temperature self-compensation ammonia nitrogen all-optical fiber detection sensor and a preparation method thereof, the temperature self-compensation ammonia nitrogen all-optical fiber detection sensor is formed by cascading an SMF-TCF-NCF-SMF structure generating Mach-Zehnder interference and an SMF-HHF-SMF structure generating an anti-resonance effect, and STNS and SHS simultaneously excite an MZI valley and an AR valley in the same spectrum. The refractive index of the TCF coating is changed by utilizing the change of ammonia concentration, so that MZI valley wavelength drift is caused, and the ammonia concentration in water is detected; and the refractive index of air in the HCF is changed by temperature change, so that the valley wavelength drift of the AR is caused, and temperature detection is realized. The ambient temperature is directly obtained by demodulating the AR valley, then the ambient temperature and the MZI valley are jointly demodulated to obtain the ammonia concentration after temperature interference compensation, and finally high-precision measurement of the ammonia concentration in water is achieved.

A computer-implemented method for reconstructing MRI images of a body includes the steps of: a) acquiring a set MRI signal samples (sq) at different k-space location along a k-space trajectory; b) acquiring or estimating a B0 inhomogeneity map ΔB0(r), wherein B0 is a static magnetic field for polarizing nuclear spins of the body and r represents position in image space; c) initializing an image (f); d) updating the image by a performing a data-consistency operation in k-space, wherein conversion between image space and k-space is performed through a non-uniform discrete pseudo-Fourier transform operator taking into account the B0 inhomogeneity map obtained from step b) to correct for off-resonance effects; and e) further updating the image by using an image-correction neural network. A computer program product and a magnetic resonance imaging apparatus for carrying out such a method is also provided.

The invention discloses a composite noise reduction structure based on a local resonance principle and a preparation method thereof, and belongs to the field of design and processing of composite noise reduction structures. The structure comprises an epoxy resin supporting panel, a metal ring-elastomer local resonance unit and a porous material, and efficient suppression of broadband noise is achieved through combination of the local resonance effect and the porous sound absorption characteristic. The resonance unit is of a structure in which a metal ring and an elastic body are mechanically embedded and are in mirror distribution; the elastic body is of a stepped cylinder structure, the metal ring is nested on a small-diameter cylinder, and the metal ring is a double-layer elastic supporting body with radial rigidity gradient after mirroring; the epoxy resin supporting panel is poured and formed through a steel mold, the elastic body is poured through a split mold, a metal ring cutting process and a porous material are processed and prepared according to requirements, and all the components are assembled into a whole through an adhesive. The invention has the advantages of obvious noise reduction effect, light weight, strong durability, simple preparation process and the like, and is suitable for noise control in various different application scenes.

The hydrogen sensor based on temperature compensation comprises a pair of multimode optical fibers, a single-mode optical fiber, a first plasma resonance structure and a second plasma resonance structure, and a protective layer is arranged outside the single-mode optical fiber; the first plasma resonance structure coats at least part of the protective layer from the first end of the single-mode optical fiber; the second plasma resonance structure coats at least part of the protective layer from the second end of the single-mode optical fiber; wherein the first plasma resonance structure comprises a first resonance layer and a first temperature sensing layer which are arranged from inside to outside, and the second plasma resonance structure comprises a second resonance layer, a second temperature sensing layer and a heating layer which are arranged from inside to outside; the first resonance layer and the second resonance layer are used for absorbing hydrogen in the environment and can generate a surface plasma resonance effect under the action of an optical signal, and the heating layer is a hydrogen sensitive material capable of reacting with hydrogen to release heat. Through the arrangement, the hydrogen concentration detection accuracy of the hydrogen sensor is improved.

The application belongs to the technical field of organic electroluminescence, and relates to a N-containing polycyclic aromatic compound and application. The application provides a N-containing polycyclic aromatic compound, which generates a multiple resonance effect through interaction of each N atom in a N-containing fused ring. The multiple resonance effect can reduce the Stokes shift of the molecule, narrow the emission spectrum, and increase the rate of intersystem crossing inversion, so that a high-efficiency, high-color-purity luminescent material is obtained.