74 results about "Resonant absorption" patented technology

The invention discloses an SERS (Surface Enhanced Raman Scattering) substrate for solution in-situ rapid detection as well as preparation and application thereof, and belongs to the technical field of substance detection. Comprising a substrate, a nanorod array film growing on the substrate, and metal nanoparticles deposited on the outer side surfaces of nanorods. The sensor has the advantages of portability of a solid substrate, strong plasmon resonance absorption in a broadband visible light region, strong surface enhancement effect and the like, and trace substances and microorganisms in a solution can be rapidly detected through the surface enhancement Raman effect; when substances in a solution are tested, pretreatment such as mixing, adsorption and drying is not needed, the limitation that in-situ detection of a traditional surface enhanced Raman base in the solution cannot be achieved is broken through, pretreatment-free in-situ and second-level ultrafast detection can be achieved, operation is easy, cost is low, and sensitivity is high. The problems that an existing SERS substrate is poor in stability and repeatability, and in-situ, ultrafast, trace and portable detection of substances in a solution cannot be achieved are solved.

The invention discloses a preparation method of a flexible infrared super-surface absorber based on MDM, and belongs to the field of micro-nano machining patterning. The method comprises the following steps: pretreating a polymer material; depositing a layer of bottom metal film on the pretreated substrate by adopting magnetron sputtering; a metal reflecting layer, a dielectric insulating layer and a metal surface functional layer are sequentially deposited through magnetron sputtering, a periodic nano microstructure is constructed on the surface of a flexible composite film, a nano round pit array is etched in situ on a surface metal layer of an MDM structure by using a femtosecond laser selective etching process, and an MDM laminated structure is formed. According to the invention, stable integration of the MDM structure and the flexible substrate can be realized, and meanwhile, high absorptivity and good flexibility of the device in an infrared band are ensured. The absorber prepared by the invention can generate resonance absorption on incident infrared electromagnetic waves through a surface plasmon and F-P cavity resonance coupling mechanism, and meanwhile, the characteristic size variation is changed through physical excitation, so that effective absorption and frequency regulation of the electromagnetic waves at the infrared band of 3-14 microns are realized.

The invention discloses a bridge type structure micro-bolometer based on a Mn-Co-Ni-O thin film and a preparation method of the bridge type structure micro-bolometer. According to the method, a Mn-Co-Ni-O post-high-temperature annealing process is considered, annealing is carried out on the suspension structure where the sacrificial layer is released, an organic sacrificial layer material release process is compatible, and the problem that cracks are generated in Mn-Co-Ni-O manufacturing due to tension and compression stress of materials of all layers of a substrate at a high temperature is minimized through annealing of the suspension structure; a bridge type structure based on Mn-Co-Ni-O is provided, and the limitation that traditional Mn-Co-Ni-O can only adopt an organic sacrificial layer and back digging to carry out thermal isolation design is eliminated; the F-P resonant cavity resonance absorption structure based on Mn-Co-Ni-O is successfully manufactured, traditional self-absorption based on a Mn-Co-Ni-O thick film is replaced, and the heat capacity of a device is reduced while absorption is enhanced by adopting a thin film optical structure; the applicable scene of the invention can be expanded to all cantilever or film-suspending micro-nano devices, such as inertial sensors, pressure sensors, chemical / biological sensors and optical detectors of other principles.

The quasi-continuous domain bound state all-dielectric metasurface dual-mode perfect absorber is composed of a plurality of periodically arranged unit structures, each unit structure comprises a metal reflecting layer, a dielectric layer and a semiconductor material layer, and the metal reflecting layer, the dielectric layer and the semiconductor material layer are sequentially arranged from top to bottom. An air circular hole is dug in the middle of the semiconductor material layer, and the center of the air circular hole is different from that of the cube. By arranging a reflection metal layer and breaking the symmetry of a unit structure, resonance absorption peaks with two modes are realized, then the influence of structural geometric parameters on the double absorption peaks and the dependence of the two absorption peaks on the polarization direction of incident light are calculated, and the sensing performance of the double absorption peaks in different refractive index environments is calculated. The narrow-band dual-mode perfect absorber is simple in structure and convenient to regulate and control, achieves the narrow-band dual-mode perfect absorber, has good sensing performance, and provides reference for further research in the fields of multi-channel sensors, optical filters, thermophotovoltaics and the like.

The application belongs to the field of heavy metal detection, and discloses a coal-fired heavy metal detection and analysis device and method based on LIBS-LAAS, which comprises a pulsed laser excitation unit, a wavelength-tunable continuous laser resonance absorption unit, a coaxial signal acquisition unit, a paraxial signal acquisition unit, a control and analysis unit and a displacement detection platform; the pulsed laser excitation unit comprises a pulsed laser, which emits pulsed laser and ablates a sample to generate plasma; the wavelength-tunable continuous laser resonance absorption unit comprises a wavelength-tunable continuous laser for emitting continuous laser to the plasma; the coaxial signal acquisition unit comprises a first spectrometer, which acquires LAAS absorption spectrum information of the continuous laser passing through the plasma. Through the application, the interference of the spectrum line overlap of the LIBS detection of heavy metal elements can be broken through, the spectrum information of multiple heavy metal elements in the coal sample can be acquired at the same time, the rapid detection and analysis of the heavy metal elements can be realized, and the accuracy of the heavy metal detection and analysis result is improved.

The modified titanium silicalite molecular sieve is characterized by containing titanium, silicon, oxygen and cesium elements, the MAS NMR spectrogram of the 133Cs at least has resonance absorption peaks of-94 + / -15 ppm,-73 + / -15 ppm and-36 + / -15 ppm. The modified titanium silicalite molecular sieve can be used in aldol condensation reaction.

The wide-temperature-range radar / infrared multi-band stealth unmanned aerial vehicle front edge component comprises a front edge body made of a carbon fiber reinforced carbon-based composite material layer, an aerogel coating is arranged on the outer wall of the front edge body, an inner side skin is arranged on the outer wall of the aerogel coating, and a honeycomb sandwich structure layer is arranged on the outer wall of the inner side skin. A frequency selective surface layer is arranged on the outer wall of the honeycomb sandwich structure layer, an outer side skin is arranged on the outer wall of the frequency selective surface layer, and an infrared coating is arranged on the outer wall of the outer side skin. The front edge component of the unmanned aerial vehicle is simple, practical and high in structure designability, the surface temperature of the front edge component of the unmanned aerial vehicle can be remarkably reduced through the aerogel coating and the infrared coating, and the infrared stealth function is achieved; the unique periodic structure unit of the frequency selective surface can realize resonance absorption of electromagnetic waves, so that wave absorption is realized, an electromagnetic wave stealth function is obtained, radar and infrared multi-band stealth is realized, and the frequency selective surface can be applied under actual complex working conditions.

The invention discloses a method for synthesizing a ZnFe2O4 photocatalyst based on ferromagnetic resonance absorption effect mediation. The synthesis method comprises the following steps: dissolving Zn (NO3) 2.3 H2O and Fe (NO3) 3.9 H2O in deionized water, and stirring to obtain a mixed solution; adding a NaOH solution to adjust the pH value; continuously heating and stirring, filtering after low-power short-time microwave heating, washing with water until the pH value of supernate is 7, and naturally drying; and continuously calcining the dried product, and then carrying out low-power short-time microwave heating to obtain the ZnFe2O4 photocatalyst with the specific surface area of 49.3-50.6 m < 2 > / g, the visible light absorption range of 580 nm and the saturation magnetization of 46.5-47.33 emu / g. The obtained photocatalyst is large in specific surface area, high in visible light absorption capacity, low in photogenerated charge recombination efficiency, easy to separate and recycle, high in photocatalytic capacity and capable of effectively removing norfloxacin in wastewater.

The invention discloses a tunable graphene metamaterial sensor suitable for aerosol ink-jet printing, and belongs to the field of biomedical engineering. The tunable graphene metamaterial sensor is obtained by arranging a plurality of element atoms on a metal reflecting layer in an array; the element atom is composed of a structural layer, a substrate layer and a reflecting layer. Observed from the upper surface, element atoms of the metamaterial are composed of a circular ring structure; the circular ring structure is made of graphene; the substrate layer is a thick layer; the reflecting layer is a thin layer and is made of gold. And the meta-atoms are arranged in an array to obtain the metamaterial absorber. The interaction between the terahertz waves and the biomacromolecules is detected by matching the change of resonance frequency by utilizing the resonance absorption characteristics of the terahertz waves and the biomacromolecules, so that the detection sensitivity of the biomacromolecules is improved. By measuring the absorption characteristics of the terahertz metamaterial sensor under different biological analyte refractive indexes, enhanced detection of biological sensing is realized, and the interaction effect of terahertz waves and biological macromolecules can be detected.

A modified titanium silicalite molecular sieve, which is characterized by containing titanium, silicon, oxygen and cesium, wherein the 133Cs MAS NMR spectrum thereof at least has resonance absorption peaks at -94±15 ppm, -73±15 ppm and -36±15 ppm. The modified titanium silicalite molecular sieve can be used in the aldol condensation reaction.

To provide a metasurface structure and gas sensor that can accurately detect targets at low concentrations of 1 ppm or less contained in gas. [Solution] Light in the ultraviolet region is irradiated onto the substrate 2 and the metal part 3 on the substrate 2, and only specific wavelengths are absorbed and reflected by surface plasmon resonance, and the gas to be detected is provided near the metal part 3. The aspect ratio of the gap between adjacent metal parts 3 along the x-axis on the substrate 2 is set to 55 / (300-10) or more and 100 or less. The aspect ratio qy of the gap between adjacent metal parts 3 along the y-axis on the substrate 2 is set to 55 / (800-163) or more and 100 / (300-296) or less. The filling factor of the metal part 3 along the x-axis on the substrate 2 is set to 10 / 300 or more and 0.99 or less. The filling factor of the metal part 3 along the y-axis on the substrate 2 is set to 163 / 800 or more and 296 / 300 or less.

The invention provides a microwave control method and a microwave controller for an electron paramagnetic spectrometer. The microwave control method for the electron paramagnetic spectrometer comprises the following steps: controlling a microwave source to generate a microwave signal for paramagnetic resonance detection; a first power division signal and a second power division signal are obtained through distribution; inputting the first power division signal into a resonant cavity, detecting a reflection signal of the resonant cavity after resonance absorption of the to-be-detected sample to obtain a first detection signal, and performing phase shift on the second power division signal to obtain an orthogonal local oscillation signal; performing frequency mixing on the first detection signal and the local oscillator signal to obtain an I down-conversion signal and a Q down-conversion signal; performing data processing to obtain detection result information; and error analysis is performed and the microwave source is corrected, so that the frequency of the output microwave signal is kept at the first working frequency. By establishing a feedback loop from output to microwave signal input of the microwave source, feedback control of microwave signals is realized, and high-precision microwave control in the electron paramagnetic spectrometer is further realized.

The invention discloses an out-of-band wave-absorbing electromagnetic window based on transverse quasi-cavity resonance, and relates to the technical field of artificial electromagnetic materials. An impedance layer is arranged and forms a series resonance circuit, so that incident electromagnetic waves excite transverse quasi-cavity resonance on metal wires of inductance structure units, absorption of low-frequency-band electromagnetic waves (C wave band) is achieved, and the electromagnetic window has the advantages of being simple in structure, low in cost and high in efficiency. Then, incident and reflected electromagnetic waves excite a surface plasmon polariton (SSPP) mode on the metal grid bars, so that energy is located in gaps of the metal grid bars and the second dielectric substrate, and the second dielectric substrate realizes absorption of high-frequency electromagnetic waves (Ku wave band), namely, compatible synergistic absorption of low-frequency resonance absorption of the impedance layer and high-frequency SSPP mode absorption of the high-frequency wave-absorbing structure is realized; meanwhile, efficient transmission of a middle wave band (X wave band) is achieved through the frequency selection surface on the lowermost layer, and finally absorption and transmission integration of vertical resonance regulation and transverse electromagnetic coupling is achieved under a wide frequency band.

The invention discloses a compact high-resolution epithermal neutron resonance absorption spectrum method and a compact high-resolution epithermal neutron resonance absorption spectrum device in the technical field of nuclear physics application, and aims to solve the problems of large size, high cost and limited application of a traditional epithermal neutron source. The method comprises the following steps: generating an epithermal neutron source with high repetition frequency and microsecond-level pulse by using a kilohertz femtosecond laser, accelerating an electron beam through a laser plasma wake field, bombarding a metal target to generate fast neutrons, and processing the fast neutrons through a polyethylene body to obtain an epithermal neutron energy spectrum with ultrahigh energy resolution; the device comprises a femtosecond laser, a vacuum target chamber, a supersonic nozzle, a high-atomic-number metal target, polyethylene, a collimator, an EJ-420 detector and other key components, and is compact in design, convenient to move and convenient for multi-scene application. The technology can realize accurate diagnosis of the type and abundance of nuclides in nuclear fuel and nuclear waste and non-contact temperature measurement in a special environment, and has important nuclear safety and nuclear guarantee application values.

The application discloses molybdenum-doped nano zinc oxide with high visible light photocatalytic performance and a preparation method and application thereof. The molybdenum-doped nano zinc oxide is prepared from 1-octadecene, 1-dodecanol, oleic acid, a zinc source and a molybdenum source through vacuum degassing treatment, uniform stirring under a nitrogen atmosphere, heating to 100-140 DEG C, keeping warm until solid particles are dissolved, heating to 220-250 DEG C, keeping warm for 0.5-1 h of reaction, and cooling, washing and drying. The molybdenum-doped nano zinc oxide produces a local surface plasmon resonance absorption peak in the range of 600-700 nm through molybdenum ion doping, and the nano powder has a diameter of 5-20 nm; and the visible light photocatalytic performance of the zinc oxide material is greatly improved under the condition of visible light.

The utility model discloses a detachable exhaust duct silencer, which relates to the technical field of silencers and comprises a frame plate mechanism, detachable sealing mechanisms are arranged on two sides of the frame plate mechanism, and a silencing resonance mechanism is inserted into the frame plate mechanism. In order to solve the problems that in the prior art, due to the fact that a silencer is prone to being blocked and needs to be replaced and maintained, forked pipes and single connecting pipes are arranged on the two sides of a frame plate mechanism, the airflow speed is reduced, local turbulence noise caused by airflow bias is avoided, a combined noise reduction scheme of source control and tail end treatment is formed, and the noise reduction efficiency is greatly improved by disassembling the corresponding arrangement of a sealing mechanism and a noise elimination resonance mechanism. The two sides of the frame plate mechanism can be opened for maintenance, the micro-perforated cylinder plates form a resonance structure through micro-holes in the plates and cavities formed by separation of the separation insertion plates, the micro-perforated cylinder plates are arranged in a staggered mode, and sound energy is absorbed through resonance of air columns at the small holes.

The present invention discloses an electrically tunable saturable absorber device based on a gold nanometer thin film, a preparation method thereof, and an application thereof, belonging to the technical field of lasers. The electrically tunable saturable absorber device includes an optical fiber substrate, a gold nanometer thin film, a metal wire electrode, and an adjustable DC power supply. The gold nanometer thin film is deposited on the optical fiber substrate by physical vapor deposition technology to form a saturable absorber device. The gold nanometer thin film is connected to the adjustable DC power supply through the metal wire electrode to form a loop. By applying a voltage to the gold nanometer thin film through the DC power supply, the purpose of dynamically regulating the linear loss and the nonlinear saturable absorption property of the device is realized. When a DC voltage is applied to the gold nanometer thin film, due to the Joule heat effect, the temperature of the gold nanometer thin film increases with the increase of the voltage, resulting in changes in the electron-phonon scattering probability and the dielectric constant in the gold nanometer thin film, thereby modulating the surface plasmon resonance absorption characteristics of the gold nanometer thin film, as well as the linear loss and saturable absorption property parameters of the device. When the electrically tunable saturable absorber is used as a modulation device in a mode-locked fiber laser, by applying a DC voltage to the electrically tunable saturable absorber, the working wavelength and pulse width of the mode-locked laser can be adjusted in real time, and the switching of the laser working state can be realized.

The invention discloses a microwave irradiation area matching method and a microwave irradiation area matching system, and relates to the technical field of intelligent energy regulation and control. Key parameters such as reflection and transmission power, three-dimensional temperature distribution, blood flow change, tissue moisture content and thickness of a target area are acquired in real time by combining a multi-mode acquisition device, and a comprehensive physiological response parameter set is constructed through multi-source signal fusion and inversion processing; calculating a tissue resonance response coefficient, judging a microwave resonance absorption state, and implementing an energy regulation strategy; a thermal response coupling coefficient is calculated, thermal effect response is evaluated, and an adjustment strategy is given; calculating a microcirculation improvement index and implementing corresponding adjustment; and finally, constructing an AI dynamic energy adjustment model by using a convolutional neural network to realize adaptive optimization of energy output. According to the method, multi-parameter real-time closed-loop regulation and control can be realized, the energy transfer efficiency and the microcirculation improvement effect are improved, and the method has the advantages of high precision, safety and personalized adaptation.

The application discloses a radar-sound compatible absorbing superstructure and a preparation method thereof, and belongs to the technical field of sound-absorbing and wave-absorbing materials.The superstructure is formed by fusing and depositing 3D printing of a wave-absorbing material, has three-dimensional gradient composition and a multistage pore structure, the multistage pore includes micro-pore and macro-pore structure, and the macro-pore structure is a space folding inclined pore.Micro-pores and macro-pores are simultaneously constructed in the superstructure, the composite effect of the micro-pores and the macro-pores is utilized to form resonance absorption peaks at different frequencies, the problem of excessive thickness / volume of a traditional radar-sound compatible absorbing material is solved, different direction incident electromagnetic waves can be fully contacted with the absorber, omnidirectional multistage reflection is realized, the folding multistage inclined pore can extend the propagation path of sound waves and radar waves without increasing the thickness of the structure, multiple reflections are formed in the folding channel, and thus sharp wave dissipation is caused in the channel.

The present invention discloses an intelligent reverse design for accelerating materials for robot-assisted automatic characterization of nanocrystals. Specifically, the following design methods are disclosed: S1) using a high-throughput preparation platform to conduct small-dose experiments; S2) constructing a small-dose experimental database; S3) designing a decision optimization disk; S4) detecting the longitudinal plasmon resonance absorption peak, absorbance ratio, and half-maximum width of the nanocrystals obtained under different reaction conditions using the decision optimization disk, and selecting the experimental conditions that are closest to the target morphological characteristics as further amplification conditions; S5) conducting amplification experiments and obtaining the morphological characteristics of the nanocrystals in each group of experiments; S6) establishing an equation between the reaction volume in the step-by-step method and the corresponding morphological characteristic parameters. The present invention implements intelligent reverse design by implementing robot-assisted automatic characterization of nanocrystals in nanocrystal amplification experiments.

The invention relates to an electromagnetic wave absorbing structure, in particular to a three-dimensional circular ring array wave absorbing structure, and belongs to the field of electromagnetic wave absorbing materials. According to the three-dimensional circular ring array wave-absorbing structure, by designing the three-dimensional hollow circular rings, resonance absorption of electromagnetic waves and multiple scattering and path dissipation are increased, meanwhile, the volume ratio of a wave-absorbing medium is reduced, and compared with a traditional flat plate wave-absorbing material, the three-dimensional circular ring array wave-absorbing structure has the advantages of being light in weight, excellent in wave-absorbing performance and the like; the dielectric substrate layer and the three-dimensional circular ring array wave-absorbing layer are integrally formed, compared with an existing three-dimensional structure wave-absorbing body, the wave-absorbing structure is easier to prepare and covered with the wave-transparent protection layer, the overall appearance of the wave-absorbing structure is of a flat plate structure, the low-frequency wave-absorbing performance and the structural stability of the wave-absorbing structure are effectively improved, and the wave-absorbing structure is suitable for the field of wave-absorbing materials.

The invention discloses a radar wave absorbing rubber patch with a periodic grid structure and a preparation method of the radar wave absorbing rubber patch, and belongs to the technical field of wave absorbing materials. According to the wave-absorbing rubber patch, a female and male mold structure is formed by rubber three-dimensional periodic structure units with wave-absorbing performance and rubber three-dimensional periodic structure units with wave-transmitting performance, and the planar rubber patch is formed through integral vulcanization. By utilizing the characteristic that the impedance of the wave-transparent structure unit is close to the air impedance, electromagnetic waves efficiently enter the wave-absorbing structure unit, multiple times of reflection, scattering, interference and resonance absorption of the electromagnetic waves are realized through a complex cavity in the wave-absorbing unit, and the problems that a traditional wave-absorbing patch is single in energy loss mode and insufficient in absorption intensity are solved. The wave-absorbing rubber patch has the characteristics of wide wave-absorbing frequency band, high absorption strength, strong designability, good processability, excellent bearing performance and the like, and the preparation process of the wave-absorbing rubber patch is strong in adaptability, easy to control and suitable for the fields of military stealth, civil electromagnetic protection, electromagnetic interference resistance and the like.

The utility model relates to the technical field of injection pumps, and discloses a low-noise injection pump set which comprises a motor, a pump head is fixedly installed on one side of the motor, and an output shaft of the motor is fixedly connected with the input end of the pump head. The protection structure is arranged outside the pump head and used for reducing noise, the multiple sound absorption plates are installed on the inner wall of the cover body, interference channels are formed through the extending parts on the two sides of the sound absorption plates, the uneven interference faces are formed on the inner wall of the cover body, sound waves generated when an impeller impacts liquid can be gradually absorbed by the interference faces, and propagation and diffusion of the sound waves are restrained; the split cover body facilitates later-stage additional installation of the protection structure, meanwhile, the acoustic board and the extension part are conveniently and independently replaced after being aged and damaged, the closed structure of the cover body prevents noise from directly leaking out, gaps of the acoustic board and the interference groove absorb energy through cavity resonance and surface reflection, and the noise reduction effect is achieved. Medium-high frequency noise is absorbed through reflection and cavity resonance.

A method and apparatus for detecting a low altitude unmanned micro-aircraft (UAV) is described. The method includes recording acoustic signals caused by mechanical vibrations of the motor and rotation of the propeller. The method is characterised in that, in addition, the optical signal of the UAV in the range of visible light (0.4... 0.76 [mu] m) and / or infrared light (0.76 [mu] m... 1 mm) is recorded, the occurrence of optical signal parameter modulation caused by these identical mechanical vibrations is detected, and the presence of a correlation of the acoustic and optical signals of the UAV is recorded, the presence of which indicates the detection of the UAV. The device (1) comprises:-a passive acoustic sensor (2),-a passive optical sensor (4), and-a correlator (3), and-an active acoustic sensor (5) adapted to operate at wavelengths at which acoustic waves resonate and scatter on the UAV, with a frequency range of 10... 20 kHz, and-an active radar sensor (6) adapted to operate at wavelengths at which the acoustic waves resonate and scatter on the UAV. The active radar sensor works at the wavelength corresponding to the signal resonance absorption wavelength in the atmosphere, the range is (1mm... 15mm), and the active radar sensor detects the UAV with the flight height of 5m... 50m.

The present invention discloses a broadband noise elimination structure based on a coiled cavity, which relates to the field of noise reduction structures. It includes a noise elimination frame, a coiled cavity, an inlet pipe, an outlet pipe, and a local resonance unit. The coiled cavity is arranged inside the noise elimination frame, and the inlet pipe and the outlet pipe are respectively communicated with the upper and lower sides of the coiled cavity. The coiled cavity is divided by a partition plate one and a partition plate two to form an S-shaped channel for sound flow, and the local resonance unit is arranged at some turning corners of the S-shaped channel. The local resonance unit absorbs the noise propagated in the coiled cavity through cavity resonance. The present invention constructs a noise elimination structure with low frequency, broadband, simple structure, light weight and thinness based on the coiled cavity structure.

The invention discloses a scanning imaging system based on an exciton resonance absorption principle. The system is composed of a semiconductor sample with exciton resonance absorption characteristics, an excitation light source, a mechanical chopper, an optical microscopic system, a displacement table, a photoelectric detector, a lock-in amplifier and a computer. The excitation light source provides narrow-band light with a specific central wavelength, the narrow-band light is irradiated to a semiconductor material sample with an exciton resonance absorption characteristic through the optical microscopic system or the lens group, and the position of the narrow-band light excitation sample is controlled through the displacement table. The narrow-band light reflected or transmitted by the semiconductor material is incident on the photoelectric detector through the optical microscopic system, and the computer processes the obtained electric signal to obtain a carrier distribution two-dimensional image in the surface of the semiconductor sample. The method has the characteristics and advantages of simple system structure, low cost and carrier dynamics visualization.

Interferometric element (IE) intended for a device for detecting at least one compound (C) exhibiting resonant absorption over a predetermined spectral region centered on a resonance wavelength, said interferometric element comprising a detection subset (DS) optimized for said resonance wavelength and comprising: a plurality of resonant Fabry-Pérot type optical cavities at said resonance wavelength, each cavity comprising a reflective layer (RS) at said resonance wavelength and a partially transparent layer (TS) at said resonance wavelength, the partially transparent layer of the sensitive cavities being permeable to the compound(s) to be detected (C); an encapsulation layer impermeable to the compound(s) to be detected (C) and encapsulating a first subset of optical cavity(ies), called reference cavities,so that each reference cavity is devoid of said compound to be detected between the reflective layer (CR) and the partially transparent layer, the encapsulating layer not encapsulating a second subset of optical cavity(ies), called sensitive cavities, so that each sensitive cavity can include the compound(s) to be detected (C) between the reflective layer (CR) and the partially transparent layer. [Fig. 1]

The application discloses a kind of based on 3D printing metamaterial mid-infrared gas sensor and preparation method thereof.The application is printed on the periodic arrangement of column arm unit on substrate using 3D printing technology, and metal film is deposited on its surface, to realize the narrow-band resonance absorption of specific wavelength mid-infrared light.The application can be adjusted by the geometric parameter and arrangement mode of column arm unit, and the absorption characteristics of sensor in mid-infrared wave band are optimized, so that it can produce resonance response to the characteristic absorption peak of target gas, thereby significantly improving the sensitivity and selectivity of gas detection.Compared with traditional planar nanostructure, the optical performance of the sensor structure design of the application is greatly improved, and it has the advantages of miniaturization, rapid response, high sensitivity and excellent gas selectivity, and can be widely used in environmental monitoring, industrial emission monitoring and safety detection and other fields.

The application discloses a kind of for low frequency broadband high-efficiency sound absorption metamaterial unit and its superstructure module, and the metamaterial unit includes the metamaterial cavity enclosed by multiple blocks of wall and the acoustic waveguide channel being arranged in the metamaterial cavity, acoustic waveguide channel is provided with impedance high-efficiency modulation sound absorption body, impedance high-efficiency modulation sound absorption body includes high porosity sound absorption medium and impedance modulation channel.The introduction of impedance modulation channel can effectively change the acoustic characteristics of high porosity sound absorption medium, by changing the geometric configuration of impedance modulation channel, can be widely modulated acoustic impedance, while producing resonance absorption peak in low frequency band, so as to significantly improve the sound absorption performance in low frequency band.A plurality of metamaterial units with different low-frequency high-efficiency absorption performance are connected in parallel, and through the coupling effect between the metamaterial units, a metamaterial module with low-frequency broadband high-efficiency sound absorption and noise reduction performance can be formed, thereby realizing low-frequency broadband high-efficiency sound absorption performance.

This invention discloses a mid-to-low frequency ventilation and sound insulation metamaterial comprising two main areas: sound absorption and ventilation. The sound absorption area is divided into inner and outer rings, each composed of multiple circumferentially arranged sound-absorbing functional cavities. Each functional cavity includes a resonant cavity formed by partitions and a perforated cavity formed by micro-perforated plates. The perforations on the plates are positioned according to the centroid of the vertical projection of the functional cavities. The ventilation area is a cylindrical region enclosed by the inner ring functional cavities, forming a complete resonant cavity via a ring-shaped base plate. This material combines the resonant characteristics of a Helmholtz resonator, achieving mid-to-low frequency broadband sound insulation through multiple parallel HR combinations. The hollow tube design ensures ventilation, and the mid-to-low frequency band utilizes a non-local coupling sound absorption mechanism for sound insulation. A 4.6cm thick specimen can block 90% of incident wave energy (TL≥10dB) in the 435~1700Hz range, and customized designs can be achieved simply by adjusting the aperture. The improved design incorporates a connecting small hole in the center of the inner and outer functional cavity partitions to form a connected functional cavity, bridging the gap between resonance absorption peaks and enhancing low-frequency sound absorption. The improved unit can achieve the same sound insulation effect in the range of 385~1700Hz.