Abstract: The application relates to a distributed acoustic sensing voice message recognition system and method. The system includes a sensing optical fiber, configured to receive a voice message and convert the voice message into a voice signal; a laser emission unit, configured to emit a laser signal with a narrow linewidth and with spontaneous emission noise being eliminated; a circulator, configured to transmit the laser signal to the sensing optical fiber to monitor the voice signal, and receive a backward Rayleigh scattering signal from the sensing optical fiber; a collection unit, configured to collect the backward Rayleigh scattering signal emitted by the circulator; and a convolutional recurrent network unit, configured to perform complex field mapping on the backward Rayleigh scattering signal collected by the collection unit, to reconstruct the voice signal.

Abstract: A porous Tin (Sn) particle and its preparation method are presented in the present invention. The preparation method includes 1) an ultra-high cooling rate solidification process of a two-component metal melt, 2) milling the resulting 2-component solid metal mixture, 3) dissolving one of the metal components in an alkaline or acidic aqueous medium. The porous particles can then be used to produce a porous electrode where the porous particle is made to react with lithium or sodium and where said electrode is part of a lithium or sodium-ion battery with the aim of improving capacity and lifetime of that battery.

Abstract: The present application provides a multi-wavelength laser for synchronously monitoring the temperature and pressure of an ocean. A pulse controller is used to convert a broadband laser outputted by a broadband laser source into a broadband pulsed light, and then a phase shifted fiber bragg grating unit is used to demodulate a plurality of pulsed light with different wavelengths from the broadband pulsed light. The pulsed light outputted by the laser is emitted into a sensing fiber in seawater via a wavelength division multiplexer, scattered light is returned to a control demodulation module via the wavelength division multiplexer, the control demodulation module demodulates the scattered light, so that the dynamic pressure is parsed according to a phase change of a light signal, and the seawater temperature is parsed according to a wavelength change of the light signal.

Abstract: This invention relates to materials for the negative electrode in non-aqueous rechargeable alkali-ion batteries in free-standing form. In particular, this invention relates to the use of metal ribbon that is produced by melt spinning directly as a battery electrode. The invention also relates to a method producing a highly dispersed, multiphase composite material in a single step, as well as a way to generate porosity while maintaining the ‘binder-free’ and ‘additive-free’ characterization of the electrode.

Abstract: A laser with a hexagonal semiconductor microdisk to solve the problems of a low quality factor of a hexagonal whispering-gallery mode and light exiting difficulty of a triangular whispering-gallery mode is disclosed. Based on physical characteristics of stimulated radiation of gain materials with a high refractive index, the apparatus uses a distributed Bragg reflection layer to reduce an optical loss of a microcavity laser, and uses a hexagonal semiconductor microdisk as an optical resonator and laser gain material. As an optical pump source, the laser provides an optical gain, and when the gain exceeds a microcavity laser threshold, generates laser light for exiting. By controlling a laser spot of the pump source to be located at a corner of the hexagonal microdisk, the laser light in a double-triangular whispering-gallery optical resonance mode is generated after stimulated radiation for exiting.

Abstract: The application relates to a distributed acoustic sensing voice message recognition system and method. The system includes a sensing optical fiber, configured to receive a voice message and convert the voice message into a voice signal; a laser emission unit, configured to emit a laser signal with a narrow linewidth and with spontaneous emission noise being eliminated; a circulator, configured to transmit the laser signal to the sensing optical fiber to monitor the voice signal, and receive a backward Rayleigh scattering signal from the sensing optical fiber; a collection unit, configured to collect the backward Rayleigh scattering signal emitted by the circulator; and a convolutional recurrent network unit, configured to perform complex field mapping on the backward Rayleigh scattering signal collected by the collection unit, to reconstruct the voice signal.

Abstract: The present application provides a multi-wavelength laser for synchronously monitoring the temperature and pressure of an ocean. A pulse controller is used to convert a broadband laser outputted by a broadband laser source into a broadband pulsed light, and then a phase shifted fiber bragg grating unit is used to demodulate a plurality of pulsed light with different wavelengths from the broadband pulsed light. The pulsed light outputted by the laser is emitted into a sensing fiber in seawater by means of a wavelength division multiplexer, scattered light is returned to a control demodulation module by means of the wavelength division multiplexer, the control demodulation module demodulates the scattered light, so that the dynamic pressure is parsed according to a phase change of a light signal, and the seawater temperature is parsed according to a wavelength change of the light signal.

Abstract: An EHz ultrafast modulated pulse scanning laser and a distributed fiber sensing system. A plurality of phase-shift gratings are engraved on a doped fiber, the phase-shift gratings having different central window wavelengths and a wavelength interval between the adjacent central window wavelengths being a preset fixed value. When a pump light emitted by a pump laser source is coupled by a wavelength division multiplexer and enters the doped fiber, a single-mode narrow-linewidth laser light having multiple wavelengths with a wavelength interval being a preset fixed value can be generated, by using the phase-shift gratings graved on the doped fiber. The ultrafast modulation is completed by using a time-domain control method based on an EOM. An internally frequency converted pulse light formed by splicing pulse lights whose frequencies linearly increase is obtained, thus forming the EHz ultrafast modulation of a distributed feedback fiber laser.

Abstract: This invention relates to materials for the negative electrode in non-aqueous rechargeable alkali-ion batteries in free-standing form. In particular, this invention relates to the use of metal ribbon that is produced by melt spinning directly as a battery electrode. The invention also relates to a method producing a highly dispersed, multiphase composite material in a single step, as well as a way to generate porosity while maintaining the ‘binder-free’ and ‘additive-free’ characterization of the electrode.

Abstract: A method for numerical control milling, forming and polishing of a large-diameter aspheric lens to solve long time-consuming and severe tool wear in the machining of a meter-scale large-diameter aspheric surface is disclosed. An aspheric surface is discretized into a series of rings with different radii, and the rings are sequentially machined through generating cutting by using an annular grinding wheel tool; the rings are equally spaced, there are a total of N rings, and the width of any ring is jointly determined by the Nth ring, the (N-1)th ring, positioning accuracy, and a generatrix equation of the aspheric lens, and the nth ring has a curvature radius of Rn =sqrt(R02-k*(n*dx)2); and the aspheric surface is enveloped by a large number of rings. The tool used for machining has a diameter greater than the semi-diameter of the aspheric surface, and contact area between tool and workpiece surface is rings.

Abstract: A laser with a hexagonal semiconductor microdisk to solve the problems of a low quality factor of a hexagonal whispering-gallery mode and light exiting difficulty of a triangular whispering-gallery mode is disclosed. Based on physical characteristics of stimulated radiation of gain materials with a high refractive index, the apparatus uses a distributed Bragg reflection layer to reduce an optical loss of a microcavity laser, and uses a hexagonal semiconductor microdisk as an optical resonator and laser gain material. As an optical pump source, the laser provides an optical gain, and when the gain exceeds a microcavity laser threshold, generates laser light for exiting. By controlling a laser spot of the pump source to be located at a corner of the hexagonal microdisk, the laser light in a double-triangular whispering-gallery optical resonance mode is generated after stimulated radiation for exiting.

Abstract: The present application discloses a fiber distributed acoustic sensing system, including a forward pump source, a wavelength division multiplexer, an active phase-shifted grating array, a backward pump source, and a data demodulation and processing device. The active phase-shifted grating array includes several active phase-shifted gratings engraved on a same fiber, each active phase-shifted grating having a same excitation light wavelength. The active phase-shifted grating array is configured to receive a forward pump pulse and a backward pump light pulse incident from the backward pump source, so that a forward excitation light and a backward excitation light are generated in each active phase-shifted grating, and two adjacent active phase-shifted gratings are enabled to generate excitation light self interference within a same pulse duration.

Abstract: A high-performance distributed fiber sensing system based on EHz ultrafast pulse scanning. During testing of a disturbance signal, an internally frequency converted pulse light emitted by an EHz ultrafast pulse scanning laser enters a sensing fiber after passing through a circulator, and a backward Rayleigh scattering signal transmitted by the sensing fiber enters an unbalanced Michelson interferometer after passing through a coupler. By designing an arm length difference between two interference arms, interferences sequentially occur for the backward Rayleigh scattering light at a position where lengths of two adjacent arms differ. A signal received after passing through the unbalanced Michelson interferometer includes a phase difference signal caused by an external disturbance signal in the sensing fiber.

Abstract: The present invention provides an event positioning method, device and application in a distributed fiber vibration monitoring system. When a location at which an event occurs in a sensing fiber is to be positioned, an interference field signal having a maximum optical power is obtained by comparing optical powers of respective interference field signals corresponding to backward Rayleigh scattering lights that are generated when a pulse light is transmitted in the sensing fiber. Subsequently, a sensing location of the interference field signal having the maximum optical power is calculated. Finally, the location at which the event occurs in the sensing fiber is determined, according to the sensing location and a location distribution pattern of the event. According to the positioning method provided in the present invention, by screening the interference field signals and then calculating the event location, the spatial resolution is not determined merely by the pulse width of the optical signal.

Abstract: The present application discloses a fiber distributed acoustic sensing system, including a forward pump source, a wavelength division multiplexer, an active phase-shifted grating array, a backward pump source, and a data demodulation and processing device. The active phase-shifted grating array includes several active phase-shifted gratings engraved on a same fiber, each active phase-shifted grating having a same excitation light wavelength. The active phase-shifted grating array is configured to receive a forward pump pulse and a backward pump light pulse incident from the backward pump source, so that a forward excitation light and a backward excitation light are generated in each active phase-shifted grating, and two adjacent active phase-shifted gratings are enabled to generate excitation light self interference within a same pulse duration.

Abstract: An EHz ultrafast modulated pulse scanning laser and a distributed fiber sensing system. A plurality of phase-shift gratings are engraved on a doped fiber, the phase-shift gratings having different central window wavelengths and a wavelength interval between the adjacent central window wavelengths being a preset fixed value. When a pump light emitted by a pump laser source is coupled by a wavelength division multiplexer and enters the doped fiber, a single-mode narrow-linewidth laser light having multiple wavelengths with a wavelength interval being a preset fixed value can be generated, by using the phase-shift gratings graved on the doped fiber. The ultrafast modulation is completed by using a time-domain control method based on an EOM. An internally frequency converted pulse light formed by splicing pulse lights whose frequencies linearly increase is obtained, thus forming the EHz ultrafast modulation of a distributed feedback fiber laser.

Abstract: A high-performance distributed fiber sensing system based on EHz ultrafast pulse scanning. During testing of a disturbance signal, an internally frequency converted pulse light emitted by an EHz ultrafast pulse scanning laser enters a sensing fiber after passing through a circulator, and a backward Rayleigh scattering signal transmitted by the sensing fiber enters an unbalanced Michelson interferometer after passing through a coupler. By designing an arm length difference between two interference arms, interferences sequentially occur for the backward Rayleigh scattering light at a position where lengths of two adjacent arms differ. A signal received after passing through the unbalanced Michelson interferometer includes a phase difference signal caused by an external disturbance signal in the sensing fiber.

Abstract: The present invention provides an event positioning method, device and application in a distributed fiber vibration monitoring system. When a location at which an event occurs in a sensing fiber is to be positioned, an interference field signal having a maximum optical power is obtained by comparing optical powers of respective interference field signals corresponding to backward Rayleigh scattering lights that are generated when a pulse light is transmitted in the sensing fiber. Subsequently, a sensing location of the interference field signal having the maximum optical power is calculated. Finally, the location at which the event occurs in the sensing fiber is determined, according to the sensing location and a location distribution pattern of the event. According to the positioning method provided in the present invention, by means of screening the interference field signals and then calculating the event location, the spatial resolution is not determined merely by the pulse width of the optical signal.

Abstract: An optical fiber distributed monitoring system and method is provided. The system includes a laser device, an acousto-optic modulator, a phase matching interferometer, a photoelectric detector and a phase demodulation module. After entering the phase matching interferometer, the Rayleigh backscattering light containing parameter information output from the sensing optical fiber enters the two arms of the phase matching interferometer respectively, and the light of the two arms of the phase matching interferometer is phase-modulated by the first modulation wave and the second modulation wave, respectively and then interfere with each other to generate interference light. The photoelectric detector converts a light signal into an electric signal, and the phase demodulation module processes the electric signal based on the Hilbert algorithm to obtain the parameter change of the environment under test.

Abstract: An optical fiber distributed monitoring system and method is provided. The system includes a laser device, an acousto-optic modulator, a phase matching interferometer, a photoelectric detector and a phase demodulation module. After entering the phase matching interferometer, the Rayleigh backscattering light containing parameter information output from the sensing optical fiber enters the two arms of the phase matching interferometer respectively, and the light of the two arms of the phase matching interferometer is phase-modulated by the first modulation wave and the second modulation wave, respectively and then interfere with each other to generate interference light. The photoelectric detector converts a light signal into an electric signal, and the phase demodulation module processes the electric signal based on the Hilbert algorithm to obtain the parameter change of the environment under test.