16 results about "Selective excitation" patented technology

The invention provides a conventional and detonation dual-mode spontaneous combustion propellant space engine, and belongs to the technical field of spacecraft propulsion systems. The conventional and detonation dual-mode spontaneous combustion propellant space engine comprises a propellant control valve, an engine head, an engine body and an external excitation device. The propellant control valve, the engine head part and the engine body part are connected in sequence, and the external excitation device is embedded into the outer wall of the engine body part; according to the invention, by adopting an external excitation mode, the space engine in a detonation mode is realized; by means of a selective excitation mode, the space engine capable of selecting a conventional mode and a detonation mode is achieved. The detonation combustion is applied to the spontaneous combustion propellant space engine, the upper limit of the combustion efficiency of the space engine of a constant-pressure thermodynamic cycle is broken through, and the combustion efficiency is further improved on the original basis.

This invention discloses an anti-optical interference multiplex biosensor (AMDRIL) based on Argonaute and selective optical filtering, and its applications. By using wavelength-selective excitation and optical filtering, it employs a convenient and low-cost solution to avoid optical interference in multiplex detection. AMDRIL is compatible with EHP and Vibrio... AHPND The detection sensitivity is as high as 10 per reaction. 0 Multiple copies are observed in a single tube with good specificity, and the detection process takes only about one hour. By configuring conventional LED lights, a light source filter, and an observation filter in a dark field, multiple fluorescence signals can be observed in the same tube. These signals are clearly visible and can be read with the naked eye, allowing for definitive result interpretation. AMDRIL supports EHP and Vibrio... AHPND This invention enables on-site monitoring and provides an economical and portable technology route suitable for on-the-spot detection, for multiplex nucleic acid biosensing detection with fluorescence readout capability.

The utility model discloses a quasi single mode fiber with a large mode field effective area, which comprises a fiber core, an inner cladding, a ring core layer and an outer cladding, the fiber core is wrapped by the inner cladding, the inner cladding is wrapped by the ring core layer, the ring core layer is wrapped by the outer cladding, and the refractive index of the fiber core is larger than that of the inner cladding, the ring core layer and the outer cladding. The refractive index of the ring core layer is larger than that of the inner cladding and that of the outer cladding, and the refractive index of the inner cladding is equal to that of the outer cladding. According to the embodiment of the utility model, while the effective area of the optical fiber fundamental mode is increased, the coupling crosstalk between the fundamental mode and the high-order mode can be effectively suppressed, the communication power threshold of the optical fiber fundamental mode can be further increased on the premise of not adopting complex mode selective excitation, and the optical fiber can be widely applied to the technical field of optical communication.

The application discloses a sun-cured tobacco distillation processing technology method, and relates to the technical field of tobacco processing, in particular to a sun-cured tobacco distillation processing technology method.The application constructs a mapping relationship between raw material dielectric fingerprints and thermal response characteristics, combines with a coplanar waveguide sensor array to collect data in real time, uses a neural network to predict the thermal release starting temperature of key aroma components, dynamically allocates radio frequency heating parameters, realizes a gradient heating process including low-frequency uniform preheating, medium-frequency selective excitation and high-frequency local focusing, and effectively improves the recovery rate of target aroma components and the retention rate of heat-sensitive components.The application has beneficial effects such as online self-adaptive regulation and control, high extraction efficiency and continuous model optimization.The application constructs a dielectric fingerprint-thermal response characteristic correlation model, realizes the regulation and control of a heating strategy driven by the inherent physical properties of raw materials, significantly improves the scientificity and accuracy of process control, automatically adapts an optimal thermal treatment path without manual intervention, and greatly improves batch consistency and target component recovery stability.

The application relates to a method for measuring the spin relaxation lifetime of single charge of semiconductor nanocrystals. The semiconductor nanocrystals mainly serve as light-absorbing materials, organic molecules serve as charge acceptors, and the testing is performed by using a circularly polarized transient absorption spectrum (TA) technology. The semiconductor nanocrystals are selectively excited by circularly polarized light to generate excitons, and the electrons or holes of the semiconductor nanocrystals are quickly transferred away by the charge acceptors before the spin of the charges is completely flipped, so that the excitons are dissociated, and a long-lifetime charge separation state is generated. On this basis, the spin relaxation lifetime of single charge (electrons or holes) of the semiconductor nanocrystals can be measured.

This application provides an optical super-resolution imaging method and apparatus. This method organically integrates light field manipulation and nonlinear effects, possessing both super-diffraction-limited light field focusing capabilities and selective excitation of the resonant modes of the sample to be imaged, thereby achieving deep manipulation of the scattered signal and effective improvement of super-resolution imaging.

The invention relates to the technical field of drug detection and chemical analysis, in particular to a qualitative and quantitative detection method for alkyl nitrite substances by an NMR (nuclear magnetic resonance) method, and aims to solve the problems that when the alkyl nitrite substances are detected in the prior art, the alkyl nitrite substances are complex in matrix and cannot be accurately qualitatively detected, and the detection accuracy is poor. In order to solve the problems that in the prior art, a sample to be detected is directly detected after being dissolved in a deuterated reagent at room temperature by utilizing the low-temperature detection characteristic of NMR (nuclear magnetic resonance), and by combining a hydrogen nuclear magnetic resonance spectrum, a one-dimensional selective excitation total correlation spectrum and a diffusion sequencing spectrum, the content of the alkyl nitrite substances is determined. Reliable qualification in a complex matrix is realized; meanwhile, absolute quantification is realized by adopting a stable and easily available internal standard substance 1, 4-dimethoxybenzene, and a deconvolution fitting algorithm is introduced to process signal overlapping in combination with a quantitative nuclear magnetic resonance hydrogen spectrum and a quantitative nuclear magnetic resonance carbon spectrum, so that the anti-interference capability and the result credibility of quantitative detection are improved.

This invention belongs to the field of optical fiber testing and sensing technology, specifically relating to a method for identifying faults and disturbances in few-mode optical fibers using Raman-enhanced time-domain reflectometry (TDDR). The method includes: signal transmission based on pulse coding and mode-selective excitation; signal-to-noise ratio enhancement based on distributed Raman amplification; mode demultiplexing and mode field detection; coded demodulation and reconstruction using a multi-mode few-mode optical TDDR; multi-dimensional fault identification based on mode-dependent loss and coupling characteristics; and multi-mode differential and high-precision positioning based on digital signal processing. This invention targets high-capacity communication and distributed sensing systems using few-mode fibers. It solves the problem of detecting weak inter-mode scattering signals by coordinating pulse coding gain and distributed Raman optical gain. Subsequently, it utilizes the unique mode-dependent loss and inter-mode energy transfer characteristics of few-mode fibers for joint decision-making, providing highly sensitive, multi-dimensional optical fiber link health monitoring capabilities. This method has great potential and application prospects in the operation and maintenance of next-generation space-multiplexed optical networks.

The present application relates to an elastic wave device, an acoustic surface wave filter, a communication system, and a vehicle, the elastic wave device comprising: a piezoelectric layer; the interdigital electrode is formed on the piezoelectric layer; the left side reflecting gate electrode and the right side reflecting gate electrode are located on the two sides of the sound wave propagation direction of the interdigital electrode respectively; the supporting substrate is arranged below the piezoelectric layer; wherein the propagation direction of the interdigital electrode is adjustable, and a longitudinal wave type leakage surface acoustic wave (LLSAW) mode or a horizontal shear type surface acoustic wave (SHSAW) mode is selectively excited by adjusting a sound wave propagation direction angle phi. According to the technical scheme, on-demand excitation of the LLSAW and the SHSAW is achieved on a single piezoelectric composite structure through the scheme of the adjustable propagation direction angle phi, meanwhile, the effects of low electrode loss and wide passband bandwidth are achieved, the high sound velocity characteristic is kept, clutter interference can be avoided, and the electromechanical coupling coefficient is increased.

This invention discloses a method and transceiver system for generating quasi-diffraction-free Bessel vortex waves using a dual-feed, common-aperture system. It addresses issues in existing technologies such as easy beam diffusion, lack of amplitude-phase co-control, and absence of online transceiver link verification. The generation method includes multi-feed configuration and mode setting, coordinated solution of vortex and Bessel phases, construction of a joint amplitude-phase target field, and beam generation through metasurface element parameter design and selective excitation based on PCB technology. The transceiver system sequentially connects modules for feed placement, target beam construction, element parameter mapping, array construction, beam generation, and transceiver link measurement. This invention also includes online verification. The combined amplitude-phase control, end-to-end transceiver link, and online verification of this invention form a complete technical closed loop. The generated beam exhibits characteristics such as quasi-diffraction-free operation, stable long-distance transmission, and high mode isolation, making it suitable for MIMO multi-antenna wireless transmission scenarios and supporting robust communication in multi-mode parallel transmission and complex electromagnetic environments.

The invention relates to the technical field of magnetic resonance imaging, and discloses a magnetic resonance high-quality rapid imaging method capable of reducing a visual field. The method comprises the following steps of pulse and sequence configuration, local region excitation and data acquisition, image reconstruction, regional denoising optimization and software integration. According to the magnetic resonance high-quality rapid imaging method capable of reducing the visual field, bidirectional spatial selective excitation in the frequency and phase encoding direction is realized through a single two-dimensional radio frequency pulse, a circular or elliptical region of interest can be adapted without multi-pulse matching, and meanwhile, the magnetic resonance imaging efficiency is improved by combining small FOV undersampling and an EPI sequence. The phase coding number and the k space sampling interval are optimized along with the reduction of the visual field, so that the imaging time is greatly shortened, and the relaxation attenuation blurring and partial resonance image distortion artifacts of the EPI sequence are relieved; and regional non-local mean denoising is matched.

Magnetic resonance imaging techniques integrating variable rate selective excitation (VERSE) and flow compensation along slice are described. According to an example, a method comprises determining, by a device comprising a processer, a two-dimensional (2D) spin echo sequence applicable for acquiring, via a MRI system, signal data associated with a slice of an anatomical region of a subject, wherein determining the 2D spin echo sequence comprises determining the 2D spin echo sequence in accordance with a combination of a VERSE protocol and a flow compensation along slice protocol. The method further comprises controlling, by the device, acquisition of the signal data by the MRI system using the 2D spin echo sequence, and reconstructing, by the device, an image of the slice from the signal data.

The present application relates to a target artery selective labeling method, device, electronic equipment and storage medium, comprising: acquiring a blood vessel positioning image of a target artery; determining a selective excitation pulse according to the blood vessel positioning image; and obtaining a perfusion map of the target artery by labeling according to the selective excitation pulse. The present application selects the position of the artery to be labeled, designs a selective excitation pulse targeting the artery based on a single-channel or multi-channel parallel emission platform, and applies the selective excitation pulse to the labeling section in the artery spin labeling sequence, thereby achieving the effect of selectively labeling a specific artery and obtaining a perfusion map of the specific artery.

This invention belongs to the field of pipeline ultrasonic guided wave detection technology. It proposes an in-pipe electromagnetic ultrasonic guided wave transducer with adjustable torsional mode and its working method. The transducer includes multiple circumferential magnet arrays arranged along the axial direction. The circumferential magnet array includes multiple main magnets and multiple auxiliary magnets distributed alternately along the circumferential direction. The magnetization directions of the main magnets and the auxiliary magnets are alternately orthogonal in the circumferential plane. By embedding circumferentially magnetized auxiliary magnets between the radially magnetized main magnets, the radial bias magnetic field strength in the pipe wall region is significantly enhanced, while electromagnetic interference in the back region of the transducer is effectively suppressed. Without increasing the magnet volume, the electromagnetic ultrasonic transduction efficiency and the excitation amplitude of the pipeline torsional guided wave are improved. By adjusting the current excitation direction of the spiral coils at different positions to change the axial distribution period of the Lorentz force at the pipe wall, selective excitation and flexible control of the pipeline torsional mode can be achieved without changing the transducer geometry.

This invention provides a device and spectrometer for the quantitative detection of carbon dioxide isotopes using a two-photon absorption method. This device is based on two-photon absorption technology. A laser frequency locking module locks the laser onto a high-precision optical cavity, ensuring the laser frequency matches the cavity's mode frequency. A piezoelectric ceramic unit adjusts the cavity length, thereby tuning the cavity's mode frequency to match the laser frequency with the energy level of the target molecular isotope, resulting in selective excitation. A signal detection module measures the transmitted light intensity of the high-precision optical cavity to obtain the two-photon absorption signal. A signal processing module analyzes and processes this signal to determine the concentration of the target molecular isotope. Because two-photon absorption has a Doppler-free property, the spectral linewidth is narrowed, effectively improving spectral resolution and isotope selectivity, thus achieving highly sensitive quantitative detection of carbon dioxide isotopes.

The invention discloses a quadrupole nuclear two-dimensional high-resolution solid NMR method based on five-quantum excitation enhancement, and the method comprises the steps: carrying out the optimization of a frequency offset satellite transition selective flip pulse based on a first change hill climbing algorithm, obtaining an LP-opt pulse, designing an LP-opt 5QMAS pulse sequence, and carrying out the time sequence of the LP-opt 5QMAS pulse sequence, the method sequentially comprises a layout number transfer enhancement pulse, a first center transition selective excitation pulse, a first LP-opt pulse, a second LP-opt pulse, a second center transition selective excitation pulse and a third center transition selective excitation pulse. According to the invention, high-order quantum transition effective excitation which is difficult to excite by a traditional rectangular pulse method is realized. Especially for a nuclear spin system with a large nuclear quadrupole interaction constant (CQ) generated due to asymmetry of a local structure, the five-quantum excitation material shows excellent five-quantum excitation efficiency in a 5QMAS experiment.