169 results about "Narrow bandwidth" patented technology

The technology described herein is directed towards modular metasurfaces arranged with unit cells for narrowband, wideband and / or multiband sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed in a server rack, proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Differently-dimensioned unit cells can be built into a single metasurface module, thereby facilitating wideband and / or multiband sound absorption with that metasurface. The modular metasurfaces can be attached to the sidewalls of a server rack, or positioned in otherwise empty slots above and below a server, optionally coupled to blanking panels for covering the openings of those slots.

The invention relates to an asymmetric transmission optical device, a test method and an electronic device, and belongs to the technical field of nano optics and photonics. Comprising a dielectric nano-particle array which comprises a plurality of dielectric nano-particles, and the dielectric nano-particles are periodically arranged according to a preset interval; wherein the height of the dielectric nano particles is 60 nm to 150 nm; and the dielectric substrate is arranged below the dielectric nanoparticle array. The test method comprises the following steps: establishing a periodic array model according to the optical device, and setting structural parameters of the model to obtain an optimal periodic array model; performing asymmetric transmission mechanism analysis and structural parameter analysis by using the optimal periodic array model; and according to an analysis result, obtaining an optimal structure parameter of asymmetric transmission. The problems of high loss, narrow bandwidth and polarization sensitivity are avoided, and the defects of high preparation difficulty, high cost and poor compatibility caused by a complex geometric structure or a specific material are overcome.

The invention relates to the technical field of video compression, in particular to a narrow-bandwidth-based video monitoring data transmission and storage method, which comprises the following steps of: for an input video monitoring data frame, calculating a difference absolute value sum between a current frame and a reference frame; according to the method, the pixel difference of the current frame and the reference frame is calculated, and the average amplitude of the motion vector field is fused to form a comprehensive index of the dynamic degree of the quantized content, so that the image group structure is not fixed or periodic any more, and the dynamic degree of the quantized content can be calculated according to the score of scene activity and the change intensity. When a monitoring picture is static, a super-long image group is established to limit a compression code rate, when the picture is suddenly changed, the super-long image group is quickly switched to a short image group to ensure instant refreshing and definition of key information, meanwhile, non-uniform redistribution is performed on limited total code rate budget, bit resources can be intelligently inclined to frames with violent content change and large information amount, and the real-time refreshing and definition of the key information are ensured. Therefore, the subjective visual quality of the key dynamic moments is improved under the narrow bandwidth.

The invention discloses a generating device capable of generating an ultra-flat broadband micro comb. The generating device comprises a pump pulse generating module, a micro comb generating module and a micro comb generating module, the pumping pulse compression module is connected with the pumping pulse generation module; the high-Q-value microcavity module is connected with the pumping pulse compression module; and the micro comb detection and feedback module is respectively connected with the high-Q-value micro-cavity module and the pump pulse generation module, and is used for monitoring the output spectrum and power change of the high-Q-value micro-cavity module and adjusting the output wavelength of the picosecond pulse light according to the output spectrum and power change so as to stabilize the ultra-flat broadband micro comb. By arranging the high-Q-value micro-cavity, the spectral bandwidth of the micro-comb can be effectively expanded, and the ultra-flat broadband micro-comb is output; meanwhile, the defects that the hyperbolic secant single soliton micro-comb is poor in flatness and narrow in bandwidth are overcome, and the micro-comb has obvious advantages in the application field with high requirements for the flatness and the spectral bandwidth at the same time.

The invention discloses a narrowband-broadband intelligent switching method of a radar, and belongs to the field of radar signal processing. Single radar wide-narrow band function integration is achieved through resource multiplexing, self-adaptive triggering and dynamic parameter configuration, detection tracking in a default narrow band mode is achieved, switching is triggered based on manual instructions and double thresholds, hardware such as a common antenna and a T / R assembly is reconstructed through time division multiplexing and software parameters, the signal synchronization time is shortened, and the target tracking response delay time is shortened; double-radar collaborative design is not needed, and the design workload is reduced. According to the invention, double radars are combined into a single radar, the hardware cost is greatly reduced, and the method is suitable for unmanned aerial vehicle-mounted, vehicle-mounted and other space-limited scenes and military reconnaissance, civil security and protection and other tasks.

The invention relates to the field of microelectronic devices, in particular to a bulk acoustic wave resonator with a double-layer piezoelectric film structure, a preparation method and a filter, the bulk acoustic wave resonator comprises a cap wafer, and a dry film, a passivation layer, a silicon oxide layer, a high-resistance silicon wafer and RDL metal are sequentially arranged on the cap wafer; the dry film and the cap wafer form a dry film cavity, the passivation layer located above the dry film cavity extends into the dry film cavity, and a top electrode, a first piezoelectric film, a middle electrode, a second piezoelectric film and a bottom electrode are sequentially arranged on the passivation layer; the top electrode and the bottom electrode are used as first ports of the resonator; and the middle electrode is a second port. According to the resonator, the excitation mode of the resonator is changed through cooperation of the two layers of piezoelectric films with the same polarization direction and the intermediate electrode, a high-order resonance mode is jointly excited, meanwhile, a high electromechanical coupling coefficient is kept, and a wide fractional bandwidth is achieved at high frequency through the relatively thick piezoelectric films; the problems that a high-frequency resonator is weak in power bearing capacity, narrow in bandwidth, low in quality factor and poor in stability are solved.

The invention provides a broadband filtering device and a multi-system access platform, and relates to the technical field of multi-system access platforms, and the broadband filtering device comprises a dielectric substrate; the resonator is arranged on the surface of the dielectric substrate; and the plurality of input units are wound on the resonator, each input unit comprises a first coupling line, a second coupling line and an input piece which are arranged on the surface of the dielectric substrate, the first coupling line and the second coupling line are connected with the input piece, the first coupling line and the second coupling line are coupled with the resonator, and the input piece is used for inputting an electric signal. According to the broadband filtering device and the multi-system access platform provided by the invention, the problem that the bandwidth is relatively narrow when a filtering device works in the prior art is solved.

The invention discloses a multispectral compatible camouflage and radiant heat management device and a multispectral camouflage system based on the same, relates to the field of multispectral camouflage materials and heat management, and aims to solve the problems of poor spectrum compatibility, narrow bandwidth, insufficient heat management and high angle sensitivity in the prior art. A phase change material layer is arranged on the metal substrate layer, and a phase regulation and control layer of a chessboard structure is arranged on the phase change material layer. According to the invention, the radar scattering cross section is large, the specular reflectance is very low, the performance can still be maintained in the incidence angle range of 0-30 degrees, the reflectance is not sensitive to the incidence angle and the polarization state, laser stealth, radar stealth and infrared camouflage can be realized, the spectrum compatibility is good, the bandwidth is wide, dynamic heat dissipation in a non-window can be realized, and the performance is stable. And the heat management effect is achieved.

The invention discloses a bent channel-Helmholtz composite low-frequency broadband sound absorber and a design method thereof. The sound absorber is formed by connecting a plurality of bent channel metamaterial sound absorption units around a Helmholtz resonator unit in parallel in a coupling mode. By controlling the impedance of the Helmholtz neck and the impedance of the bending channel, each unit is in an under-loss state, and then the overall critical coupling is realized by utilizing the area coupling effect, so that the sound absorber has the sound absorption coefficient of more than or equal to 0.5 in the frequency band of 267-382Hz under the thickness of 35mm. According to the sound absorber, broadband efficient sound absorption is achieved through impedance coupling of the Helmholtz resonators and the bent channels, the problems that a traditional structure is narrow in frequency band, difficult to regulate and control and the like are solved, and theoretical and technical supports are provided for low-frequency noise control.

The application discloses a terahertz biological tissue imaging system and method based on a metasurface antenna. The terahertz biological tissue imaging system comprises a terahertz signal generator, an intelligent system control device, a terahertz signal transmitter and a data acquisition module. The terahertz signal generator is used for generating an ultra-wideband terahertz wave signal. The intelligent system control device controls the terahertz signal generator to continuously generate the ultra-wideband terahertz wave signal. The terahertz signal transmitter is used for transmitting the ultra-wideband terahertz wave signal after programmable modulation to a biological tissue organ. The terahertz signal receiver is used for receiving terahertz biological signals scattered inside and around the biological tissue organ, and modulating the received terahertz biological signals. The data acquisition module is used for acquiring the terahertz biological signals. The intelligent sensing signal processing module is used for processing the terahertz biological signals to obtain a terahertz image of the biological tissue organ. The application solves the problems of narrow bandwidth and low gain in the corresponding technology.

The invention discloses an angle-adjustable narrow-band heat radiator based on corner hyperbolic phonon polaritons. The heat radiator sequentially comprises a metal layer, a natural biaxial hyperbolic medium, a vacuum / air spacing layer and a one-dimensional medium grating. According to the angle-adjustable heat radiator, the biaxial hyperbolic medium and the gold layer are twisted as a whole, and the included angle between the radiating surface and the plane where the crystal axis of the natural biaxial hyperbolic medium is located is changed, so that the heat radiation direction is changed. The radiator can be produced on a large scale at low cost by utilizing processes such as nano photoetching and deposition. The narrow-band directional thermal radiation device obtained through the nano manufacturing technology is stable and reliable in performance, can generate thermal radiation with narrow bandwidth and small radiation angle, has the characteristics of adjustable direction, flexibility, convenience and the like, and is expected to be applied to the fields of directional heat dissipation, thermal camouflage and the like.

The application discloses a kind of communication link establishment initial stage security authentication encryption method, device and storage medium, the present application is limited to narrow bandwidth for end-to-end wireless communication link establishment, cannot apply conventional encryption preparation, it is difficult to guarantee that preset symmetric key is added after planning, abandon password protection is also prone to be maliciously controlled and so on Problem, an authentication encryption adaptive method based on pre-stored and diffusion key is proposed, by making full use of the key storage space of end device pre-stored key, supplemented by the diffusion transmission of new key with the process of link establishment, combined with the two modes of offline preset loading when opening and automatic online interaction after new communication terminal joins interworking, under the premise of no manual participation, maximum reduction to the occupation of link establishment narrow band, the security of information transmission is greatly improved, so as to improve user experience.

The utility model relates to a dual-channel optical filter based on a three-rectangular cavity edge coupling waveguide. The dual-channel optical filter comprises a silicon substrate, a sapphire layer, a graphene nano-strip waveguide, a first graphene rectangular resonant cavity, a second graphene rectangular resonant cavity and a third graphene rectangular resonant cavity, the sapphire layer is arranged above the silicon substrate; a graphene nano-strip waveguide, a first graphene rectangular resonant cavity, a second graphene rectangular resonant cavity and a third graphene rectangular resonant cavity are arranged on the upper surface of the sapphire layer; the first graphene rectangular resonant cavity and the third graphene rectangular resonant cavity are connected in series and arranged on one side of the graphene nano-strip waveguide, and the second graphene rectangular resonant cavity is arranged on the other side of the graphene nano-strip waveguide. According to the utility model, the problems of narrow bandwidth and poor filtering effect of an optical filter with a graphene structure are solved; the dual-channel optical filter which is small in size, wide in bandwidth, excellent in filtering effect, dynamically tunable and easy to integrate is realized in an infrared band.

The invention belongs to the technical field of communication, and particularly relates to a resource data sensing method and device and communication equipment, and the resource data sensing method comprises the steps that a sensing node collects multi-dimensional environment parameters and generates environment feature vectors, and a current interference type is recognized based on an interference classification model; according to the identified interference type, selecting an anti-interference algorithm combination corresponding to the first order from an anti-interference strategy library; adjusting a sensing parameter based on a dynamic parameter in the environment feature vector, and collecting and preprocessing target resource data to obtain noise-reduced resource data; evaluating the confidence coefficient of the denoised resource data, and if the confidence coefficient reaches the standard, outputting the resource data; if the confidence degree does not reach the standard, strategy iteration is triggered until resource data with the confidence degree reaching the standard are output, the method can adapt to diversified interference of narrow bands, wide bands and the like, matching of interference types and anti-interference strategies is achieved, interference is restrained to the maximum extent, the data distortion rate in the complex environment is reduced, and high-reliability data support is provided for resource scheduling.

This disclosure provides methods, components, devices and systems for transmission of resource units by narrow bandwidth operating devices in wide bandwidth spectrum. A station (STA) may identify or receive a resource unit (RU) allocation including a global RU index for a wide bandwidth. The STA may translate the global RU index into a local RU index for a local tone plan, may map the assigned RU to distributed RU (dRU) tones over a corresponding distribution bandwidth, and may shift the mapped dRU tones to align with the wide bandwidth. The STA also may support transmission of short training fields (STFs) and long training fields (LTFs) using a similar mapping and shifting, or using tones of the wide bandwidth that fall within the distribution bandwidth region. A STA also may support a tone plan splitting a wide bandwidth into segments of the distribution bandwidth to allow direct mapping.

The application discloses a microwave photon frequency hopping signal generation device and method based on an optical switch and belongs to the technical field of optical communication. The application is composed of a light source, a beam splitter, an optical frequency comb generator, an electro-optical frequency shifter, an acousto-optic modulator, a digital frequency synthesizer, a filter array, a signal control unit, an electrically controlled high-speed optical switch, a beam combiner and a photoelectric detector. The application separates optical frequency comb teeth by using an ultra-narrow bandwidth optical filter, selects and opens the frequency hopping signal generated by the local light beat frequency through the optical switch, and can generate a high-speed high-order high-stability frequency hopping signal compared with the prior art.

A user equipment comprising: means for detecting one or more synchronisation signals on a synchronisation raster point of a first synchronisation raster and when a synchronisation signal is not detected, searching for one or more synchronisation signals on another synchronisation raster point of the first synchronisation raster, the first synchronisation raster being associated with a first synchronisation signal and physical broadcast channel configuration having a relatively narrow bandwidth compared to a second synchronisation signal and physical broadcast channel configuration which is associated with a second different synchronization raster, one or more synchronisation signals of the first synchronisation signal and physical broadcast channel configuration being associated with a first sequence length and one or more synchronisation signals of the second synchronisation signal and physical broadcast channel configuration being associated with a second different sequence length; means for detecting one or more master information blocks of a first physical broadcast channel associated with the one or more synchronisation signals, when the one or more synchronisation signals are detected; and means for performing an initial access of a cell associated with the first physical broadcast channel.

This invention discloses a method for encrypted transmission of IoT sensor data for NB-IoT, relating to the fields of IoT communication and information security technology. The invention constructs an association mapping relationship between wireless channel coverage enhancement level, transport block size index, transport block bit length, and number of repeated transmissions, and matches the optimal transport block configuration by combining transmission resource overhead budget. Based on channel state and transmission capacity, it performs adaptive encryption and data compression processing, generates implicit random numbers, and completes data encapsulation. Stable transmission of the encapsulated data is achieved through the narrow bandwidth channel of NB-IoT, and consistency verification is performed at the receiving end. This effectively solves the problems of poor adaptability and high transmission overhead of traditional encryption schemes, improving the security, efficiency, and reliability of IoT sensor data transmission.

The invention discloses a quantum key distribution system and method capable of tolerating a high-noise link, and the method comprises the steps: carrying out the specific ultra-narrow bandwidth configuration in a transmitting terminal and a receiving terminal of QKD equipment at the same time; in this way, the capability of tolerating a high-noise link can be provided for a QKD system especially under the scene that classic optical communication equipment and QKD equipment have a small wavelength interval of 25GHz or an integral multiple of 25GHz, and the power of a classic optical signal does not need to be lowered or the classic optical signal and a quantum optical signal do not need to be configured on two wavebands with a large interval to reduce noise. The power and the wavelength of classical optical communication equipment do not need to be limited too much, practical engineering application can be greatly facilitated, the quantum optical signals and the classical optical signals can achieve small link attenuation at the same time, and the method is suitable for long-distance scenes.

The invention discloses a polarization imaging system and a configuration method thereof, and the system comprises a first light source which is used for providing wide-bandwidth illumination, a polarization camera which is used for imaging a target object under the illumination of the first light source, and a processing model which is used for determining a polarization information image according to the imaging information outputted by the polarization camera. The configuration method comprises the steps that first polarization information and second polarization information are obtained, the first polarization information is obtained by imaging a target object through a polarization imaging system, the second polarization information corresponds to polarization information of the same target object under narrow-bandwidth illumination, and the first polarization information and the second polarization information are obtained based on the first polarization information and the second polarization information; and determining a loss value, and updating the configuration of the processing model based on the loss value. According to the configuration method provided by the invention, the system can consider the advantages of cost, power consumption and packaging size, and has the functions of achromatism and reduction of polarization information loss.

The present invention proposes a control method, device, electronic device, and storage medium for a piezoelectric nanopositioning system based on rolling optimization, belonging to the field of precision electromechanical control technology. The method comprises: establishing a high-order transfer function model of a piezoelectric nanopositioning system and identifying the model parameters through a frequency sweep method; secondly, converting the model into a high-dimensional state space model, designing optimal control indicators, constructing a finite-time rolling optimization control problem, and improving the tracking capability of the piezoelectric nanopositioning system; finally, converting the rolling optimization control problem into a quadratic programming problem, and designing a coordinate descent method to accelerate the online calculation of the optimal control and ensure that the optimal control input satisfies the state and input constraints of the system. The method of the present invention can solve the problems of existing piezoelectric nanopositioning systems, such as the low order and limited expression capabilities of mathematical models, the narrow bandwidth of control methods, and the difficulty of digital implementation, thereby improving the ability of piezoelectric nanopositioning systems to track high-frequency reference instructions and being suitable for engineering applications.

The invention discloses a double-filtering circular polarization phased-array antenna unit and array, and belongs to the technical field of phased-array antennas. The dual-filtering circularly polarized phased-array antenna unit comprises a parasitic patch layer, a first dielectric substrate layer, a coupled feed layer, a semi-cured layer, a second dielectric substrate layer, a strip-shaped feeder line layer and a third dielectric substrate layer which are sequentially arranged from top to bottom, the strip-shaped feeder line layer comprises a feed strip-shaped line and a filtering branch knot located on the feed strip-shaped line. The parasitic patch layer comprises a central patch and a zero-order filtering resonator located on the periphery of the central patch. According to the invention, the limitation of narrow bandwidth of the existing antenna is solved, and the antenna is low in cost, low in profile and high in efficiency.

The application discloses an equal-wavenumber division waveband noise reduction method for an infrared Fourier transform spectrometer, and is applied to fine spectral detection with wide spectral range and ultrahigh resolution. When designing a low-temperature infrared Fourier transform spectrometer, a low-temperature filter wheel is arranged in an optical path in front of a detector, and the low-temperature filter wheel is driven by a low-temperature motor. A plurality of filters are arranged on the filter wheel, the central wavelengths of the filters are different, the central wavelength intervals are different, the central wavelengths and the bandwidths of the filters are designed according to equal central spectral intervals, each filter has a narrow bandwidth, and according to a spectral range of a required detection target, a corresponding filter is selected to realize spectral detection with ultrahigh spectral resolution of a concerned spectral range. For the infrared Fourier transform spectrometer with high spectral resolution and wide spectral bandwidth, the measurement brings the advantage of reducing noise caused by out-of-band photons on the detector, and low temperature of the filter reduces infrared background and photon noise caused by the filter body.

The application discloses a full-band super-high power density electromagnetic pulse protection energy selection surface and a communication device. The energy selection surface comprises a first dielectric substrate and a second dielectric substrate which are sequentially stacked. The first dielectric substrate and the second dielectric substrate are separated by an air gap layer. The top of the first dielectric substrate is provided with a first metal unit, and the bottom of the second dielectric substrate is provided with a second metal unit. The first metal unit and the second metal unit are both center-symmetric structures. The application realizes adjustable functions, can switch between transmission and shielding states, breaks the limitation of the single function of the frequency selection surface and the limitation of the narrow bandwidth of other energy selection surfaces.

The application provides a bandwidth high-power voltage-controlled oscillator circuit, which works in cooperation with a frequency selection unit, an oscillation unit and an amplification unit: the frequency selection unit is connected with an input unit, can control an output frequency according to an input voltage, and solves the problem of narrow bandwidth of a high-power scheme; the oscillation unit forms a feedback loop with a field effect tube and a feedback network, receives a frequency selection unit signal and generates a first signal, and guarantees stable generation of an oscillation signal; the power tube gate of the amplification unit is connected with the field effect tube, the drain is connected with an output unit, the first signal is amplified into a high-power second signal, and the power defect of a low-power scheme is compensated. Meanwhile, the structure of direct correlation of each unit reduces unnecessary intermediate links, reduces the number of components, reduces heat generation and signal loss, and improves the stability of the circuit.

A broadband high-transmittance tuning ratio optical switch and its preparation method, which belongs to the field of smart materials and optical films. The present invention aims to solve the problems of existing optical switches, such as low transmittance and narrow bandwidth, and the long recovery time required to return to the initial high-transmittance state with the help of external stimulation once a phase change occurs. The broadband high-transmittance tuning ratio optical switch is composed of a transparent substrate, an anti-reflection layer and a VO2 layer; the anti-reflection layer and the VO2 layer are arranged on both sides of the transparent substrate from the inside to the outside; or the anti-reflection layer and the VO2 layer are arranged on one side of the transparent substrate from the inside to the outside, and the anti-reflection layer is arranged on the other side. Preparation method: 1. Cleaning the substrate; 2. Preparing the anti-reflection layer; 3. Preparing the VO2 layer. The present invention is used for a broadband high-transmittance tuning ratio optical switch and its preparation.

The invention discloses a spread spectrum signal tracking method and system, and belongs to the field of signal processing. According to the invention, the spread spectrum digital signal is generated by performing oversampling on the acquired spread spectrum modulation signal. In-phase and quadrature components are generated by performing mixing, de-spreading and coherent integration on the digital signal, and frequency and phase error information is calculated based on the components at continuous moments for correcting local carriers. The corrected local carrier is then utilized to mix the signal to a baseband, and a target fractional delay is determined by applying an adjustable fractional delay and searching for an instant correlation energy peak to obtain code phase error information. After the code phase error information is utilized to correct the local pseudo code, the corrected local carrier and local pseudo code are utilized to initialize a narrow-bandwidth frequency-locked loop, a phase-locked loop and a delay-locked loop so as to start accurate tracking, and high-precision stable locking of spread spectrum signals can be realized in a short time.

The application discloses an improved trapezoidal line slow wave structure and a traveling wave tube. The slow wave structure comprises a straight waveguide section, the straight waveguide section comprises a first coupling groove, a second coupling groove and an electron beam channel located in the middle of the first coupling groove and the second coupling groove along the direction of the central axis of the straight waveguide section; the width of the first coupling groove and the second coupling groove alternately changes on two adjacent metal plates of the slow wave structure, the transmission path of electromagnetic waves in the slow wave structure is prolonged, the phase velocity of electromagnetic waves in the slow wave structure is reduced, and then the bandwidth is extended. The traveling wave tube comprises the improved trapezoidal line slow wave structure. The application has the advantages of easy processing, good heat dissipation, wider bandwidth, higher coupling impedance and lower ohmic loss in the terahertz wave band, and solves the problems of narrow bandwidth, lower coupling impedance and larger loss of the traditional trapezoidal line slow wave structure.

The invention provides an encodable liquid crystal image processor, a preparation method and a broadband parallel imaging device. The encodable liquid crystal image processor comprises a first substrate, a second substrate and a cholesteric liquid crystal layer which are oppositely arranged, one side of the first substrate is provided with a first orientation layer, and one side of the second substrate is provided with a second orientation layer; the first orientation layer and the second orientation layer comprise control patterns, and the control patterns enable liquid crystal directors to meet orientation angle distribution so as to guide liquid crystal distribution in the cholesteric liquid crystal layer; in a wave band covered by a chiral photonic band gap of the cholesteric liquid crystal layer, space parallel image processing with multiple functions is realized at the same time. According to the invention, a multi-task image processing function, such as edge detection and corner detection, is integrated on a single element, and spatial parallel output is realized in a visible light wave band by utilizing the broadband geometric phase modulation characteristic of cholesteric liquid crystal, so that the limitations of single function and narrow bandwidth of an existing image processing device are effectively improved.

The invention discloses a carbon dot with high fluorescence quantum yield and narrow bandwidth emission, which is prepared by taking citric acid and rhodamine 6G as carbon sources for hydrothermal reaction, and emits orange fluorescence under ultraviolet excitation, the emission wavelength is 556 + / -2nm, the fluorescence quantum yield is not less than 80%, the half-peak width is not more than 50nm, and the narrow bandwidth characteristic of the carbon dot can effectively improve the light color purity. And when being applied to preparation of a high-color-purity photoluminescent diode as photoconversion fluorescent powder, the fluorescent powder shows excellent optical performance.