110 results about "Pulse spectrum" patented technology

Light pulses can be stopped and stored coherently, with an all-optical process that involves an adiabatic and reversible pulse bandwidth compression occurring entirely in the optical domain. Such a process overcomes the fundamental bandwidth-delay constraint in optics, and can generate arbitrarily small group velocities for light pulses with a given bandwidth, without the use of any coherent or resonant light-matter interactions. This is accomplished only by small refractive index modulations performed at moderate speeds and has applications ranging from quantum communications and computing to coherent all-optical memory devices. A complete time reversal and / or temporal / spectral compression and expansion operation on any electromagnetic field is accomplished using only small refractive index modulations and linear optical elements. This process does not require any nonlinear multi-photon processes such as four-wave mixing and thus can be implemented using on-chip tunable microcavity complexes in photonic crystals. The tuning process requires only small refractive index modulations, and moderate modulation speeds without requiring any high-speed electronic sampling.

This invention refers to a method and device for measuring super short laser pulse, which adopts different optical structure with traditional Spectral Phase Interferometry for Direct Electric-field Reconstruction (SPIDER), sum-frequency of the copy pulse of a pulse to be measured with two quasi-monochrome long pulses with different frequency to generate two frequency spectrum sheared sum-frequency, leading defined small time delay between said two pulses through piezoelectric driven single reflection mirror or step reflection mirror, combined with measured single sum-frequency spectrum to calculate point-to-point spectrum phase difference of pulse to be measured, then reconstructing pulse spectrum phase without using Fourier transformation filter process.

The invention relates to a new method for measuring an ultrashort light pulse spectral phase in the field of information optoelectronics and a device thereof. According to the method, a time delay minus T with polarity is introduced between two quasi-monochromatic light components with frequency Omega generated by the chirped stretching of a pulse to be detected; an additional time delay plus T, which is introduced between two quasi-monochromatic light components due to a pulse stretcher, is compensated to be in synchronization with the pulse to be measured and generate two sum frequency lights together with the pulse through a sum frequency crystal; respective power spectra and coherent spectra without interference fringe are acquired through a spectrometer. The phase difference between the two sum frequency lights is calculated by the three spectra through formulae. A spectrum phase curve of the pulse to be measured is calculated by adopting a concatenated method. The method can accurately determine the phase difference polarity of the pulse spectrum, and provide the simple, real-time, rapid and accurate measurement method and the device thereof for measuring the ultrashort optical pulse spectral phase.

The invention relates to an optical signal technology physical method for preserving vegetables and fruits and an optical signal generating device. By adopting a computer programmable pulse scanning signal generator, the invention controls a light-emitting device with a red, green and blue light source pack to generate a pulse-type optical signal or an optical signal of a pulse-type periodical scanning combined spectrum so as to illuminate fresh vegetables and fruits stored in a storage device under a room-temperature storage condition or a temperature and moisture control condition. Under the physical environmental condition of an artificial optical signal, the illuminated fresh vegetables and fruits obtain photon energy needed for an optical reaction in photosynthesis in an optical signal illumination environment with periodical brightness change so that cell tissues recover metabolism and maintain the slow operation of metabolism and growth inertia; through controlling the optical signal of a periodical pulse spectrum or a periodical pulse scanning spectrum or a periodical pulse scanning combined spectrum, and the illuminance, the pulse period and the combined scanning mode of a visible spectrum optical signal emitted by the red, green and blue light source pack are controllable so as to achieve the aims of controlling the slow growth process of the harvested vegetables and fruits under the room-temperature condition or the temperature and moisture control condition, effectively prolonging the fresh state of the harvested vegetables and fruits by the slow metabolism operation of the preserved vegetables and fruits, keeping the freshness of the stored vegetables and fruits and prolonging the preservation time.

The invention provides a method for controlling an electronic throttle control (ETC) of an engine by a combined pulse spectrum, belonging to the vehicle gasoline engine control field, comprising a basic throttle opening pulse spectrum parameter and a dynamic throttle opening pulse spectrum parameter, wherein, the basic pulse throttle opening spectrum parameter is standardized by a jack horse or optimized and standardized by the jack horse and a road parameter, the dynamic throttle opening pulse spectrum parameter is generated by the self-standardization of the self-study on line of a control system and the self-optimization, the basic throttle opening pulse spectrum parameter and the dynamic throttle opening pulse spectrum parameter form a combined pulse spectrum parameter, and the adaptively control of the opening of the ETC of the gasoline engine is controlled by the control system according to a throttle opening control strategy. The combined pulse spectrum control way synthesized by the self-adapting study method is adopted; therefore, the influence of the change in a controlled system and the unknown change on the engine is corrected, thereby improving the control accuracy of the open-loop control and increasing the speed and improving the timeliness of the control.

The invention discloses a frictional torque compensation method and device as well as an idle speed control method and system and belongs to the field of automobile electronic control. The frictional torque compensation method comprises the following steps: inquiring an initial frictional torque from a prestored torque pulse spectrum table according to the current engine operating parameter; carrying out double integration on the D-value of the current revolving speed and a target revolving speed to obtain a frictional torque compensation value; and adding the initial frictional torque and the frictional torque compensation value together to obtain a final frictional torque. The frictional torque compensation system realizes the frictional torque compensation method, and the idle speed control method and an idle speed control system utilize the final frictional torque acquired by the compensation to carry out idle speed control; the D-value of the current revolving speed and the target revolving speed is subjected to double integration so as to obtain the frictional torque compensation value, thereby effectively reducing or eliminating the difference of the frictional torque obtained through searching the table and the actual frictional torque of an engine; and the final frictional torque after compensation is utilized to realize more stable idle speed control.

The invention relates to an EGR rate correction system and method based on the filling factor of an internal combustion engine, and belongs to the field of engines. The method is based on the fillingfactor calibration pulse spectrum in the laboratory standard environment. The strong correlation between the filling factor and the inlet manifold gas temperature is adopted to conduct temperature correction to the filling factor. The actual EGR rate is calculated with the definition equation of filling factor. The actual EGR rate is compared with the target EGR rate calibration value or modifiedvalue to complete closed loop feedback control of the EGR valve opening. The EGR rate correction system and method can accurately determine the EGR rate of the engine in practical use when the EGR system and an intercooler deviate from laboratory calibration conditions due to the operation reasons such as fouling or efficiency change; additional sensors in addition to standing sensors are not required to added; and the characteristics of rich functions and being suitable for promotion are achieved.

The invention relates to an all-optical quantification system and an all-optical quantification method based on dynamic spectrum compression. The all-optical quantification system comprises a high-nonlinearity optical fiber for converting an optical signal subjected to all-optical sampling into an optical pulse signal subjected to frequency shifting, a dynamic power equilibrium unit for performing power equilibrium on optical pulses with different wavelengths of the optical pulse signal and acquiring an optical pulse signal subjected to power equilibrium, a comb-shaped optical fiber for performing spectrum compression on the optical pulse signal subjected to power equilibrium and thus acquiring an optical signal subjected to spectrum compression, and a dispersion element for performing space separation on the signal subjected to spectrum compression and thus acquiring an quantified signal, wherein the high-nonlinearity optical fiber, the dynamic power equilibrium unit, the comb-shaped optical fiber and the dispersion element are sequentially connected. The all-optical quantification system has the advantages that the shortcomings of three pulse spectrum compression methods in the background technology are effectively overcome, the all-optical qualification precision is also improved, and the complexity of the all-optical quantification system based on soliton self frequency shifting (SSFS) is reduced; and the blank of a dynamic power control part in an all-optical analog to digital converter (ADC) is made up.

The invention provides a method for controlling a fuel injector of an engine by a combined pulse spectrum, belonging to the vehicle gasoline engine control field, comprising a basic fuel injecting pulse spectrum parameter and a dynamic fuel injecting pulse spectrum parameter, wherein, the basic fuel injecting pulse spectrum parameter is standardized by a jack horse or optimized and standardized by the jack horse and a road parameter, the dynamic fuel injection pulse spectrum parameter is generated by the self-standardization of the self-study on line of a control system and the self-optimization, and the adaptively control of the fuel injector of the gasoline engine is controlled by the control system according to a fuel injecting pulse width control strategy. The combined pulse spectrum control way synthesized by the self-adapting study method is adopted; therefore, the influence of the change in a controlled system and the unknown change on the engine is corrected, thereby improving the control accuracy of the open-loop control and increasing the speed. The self-adapting study controls the strategy generating a dynamic fuel injecting pulse spectrum and advances the predictive control, thereby correcting the control lag generated by various time-lag effects and improving the timeliness of the control.

A chirped-pulse fiber amplification method and system operates with large nonlinear phase shifts (as large as ˜20π or more). In this regime, the pulse spectrum is modified by strong self-phase modulation and gain shaping. With large-enough nonlinear phase shift, substantial spectral broadening occurs. The amplified spectrum can therefore be much broader than the spectrum that is obtained with small nonlinear phase shifts. The broader spectrum enables the formation of a shorter pulse, and the bandwidth generated in nonlinear chirped-pulse amplification can in fact be exploited to generate shorter pulses. Ultimately, this allows the generation of pulses shorter than the gain-narrowing limit of a fiber amplifier.

A method and apparatus comprising four co-planar metallic plates, two for transmission and two for reception, in which each pair of co-planer metallic plates of overall length L are disposed either in direct contact with the earth or are elevated a distance Z above the earth to form a capacitor comprising the metallic plates and the earth if Z=0 or if Z>0, the metallic plates, the air space and the earth. A short voltage or current pulse is applied to this capacitor via a transformer in which the magnetic flux current is adjusted to provide a pulse of the desired frequency composition in the air-earth propagation medium. This results in a frequency controlled pulse of electromagnetic radiation into the targeted subterranean geology at frequencies <500 KHZ. In the preferred embodiment, the electromagnetic radiation that has propagated through the subsurface is iterated against a theoretical model for earth propagation of vertically traveling up-going and down-going waves to get a solution for the magnitude of the electrical properties as a function of the depth in the medium through which these waves have traveled. Electrical property vs depth profiles of the relative dielectric and the conductivity in addition to wave velocity and attenuation rate at depth in the subsurface are recovered by the iteration. For operation at capacitor altitude Z above the surface of the earth, the overall size of the capacitor, L, can be specified for use in the pulse spectrum below 500 khz.

The invention provides an oil injection timing control system aiming at a double-swirl combustion system and a control policy thereof. The invention has the advantages that fuel jets under different working conditions and a double-swirl combustion chamber 2 are matched and optimized by using a modern precise control technology, and an oil injection advance angle is exactly controlled; under an idle speed and a small load, an injection starting point is a function of the oil injection quantity and the rotating speed of the diesel engine and is obtained through a demarcated pulse spectrum, and under a large load, the injection starting point is commonly decided by the rotate speed of an engine, in-cylinder pressure and injection pressure; at the moment, a fuel oil bundle passes through an arc ridge, and is split into two parts and distributed to an inner chamber and an outer chamber in a best proportion; double swirls are formed so as to more quickly form uniform combustible mixing gas and ensure that combustion is quick and perfect without large inlet vortex flows; and the economical and dynamic indexes of the engine are improved, and the discharge of harmful pollutants can be reduced.

The invention discloses a method for monitoring the state of an air filter. The method comprises the following steps that 1, an intake resistance pressure sensor is used for detecting intake resistance of the air filter under different air intake flow, so that actual intake resistance under different working conditions is obtained; 2, the actual intake resistance is compared with resistance threshold value pulse spectrum, and the resistance threshold value pulse spectrum is pre-calibrated at different air intake flow; and 3, when the actual intake resistance is larger than the resistance threshold value pulse spectrum, an alarm signal is sent to remind a driver to maintain or replace the air filter. According to the method, active monitoring of the states of the air filter is realized, thedriver can be effectively and accurately reminded to maintain or replace the air filter, the maintenance cost can be reduced, the normal performance of an engine can be guaranteed, and therefore therunning state of the engine is guaranteed, and the service life of the engine is prolonged. Meanwhile, the invention further discloses a device and system for monitoring the state of the air filter.

The invention provides a method for controlling an air-fuel delivery ratio of an engine by a combined pulse spectrum, belonging to the vehicle gasoline engine control field, comprising a basic air-fuel delivery ratio pulse spectrum parameter and a dynamic air-fuel delivery ratio pulse spectrum parameter, wherein, the basic air-fuel delivery ratio pulse spectrum parameter is standardized by a jack horse or optimized and standardized by the jack horse and a road parameter, the dynamic air-fuel delivery ratio pulse spectrum parameter is the pulse spectrum of the on line self-standardization generated by the self-adaption and of the self-optimized refreshable air-fuel delivery ratio control, and the adaptivity control of the air-fuel delivery ratio of the gasoline engine is controlled by the control system according to a control strategy. The combined pulse spectrum control way synthesized by the self-adapting study method is adopted; therefore, the influence of the change in a controlled system and the unknown change on the engine is corrected, thereby improving the control accuracy of the open-loop control and increasing the speed and improving the timeliness of the control.

The invention relates to a multi-wavelength femtosecond Raman fiber laser. According to an adopted self-similarity pulse amplification method, a non-linear effect in optical fibers is utilized actively, and by adjusting the peak value in pulses in a pulse width control part, the main amplifying part laser has higher peak value, thereby triggering a high-order Raman effect, expanding pulse spectrum, and obtaining multi-order stokes and anti-stokes radiation to realize multi-wavelength output; and finally, the multi-wavelength femtosecond laser with central wavelength of 1,030nm and a spectral region of 860-1,330nm is obtained. In the high-power amplification engineering, each stokes and anti-stokes radiation has relatively high strength, so that the obtained laser of each wavelength has super-high peak value, relatively wide spectrum width and femtosecond-scale time width, which are advantages un-possessed by other multi-wavelength lasers.

The invention discloses an improved ultra wide band pulse design method based on a Gaussian function, which relates to the field of an ultra wide band pulse design. In order to maximum the power spectrum utilization of the ultra wide band pulse under the emission mask stipulated by Federal Communications Commission (FCC), the method comprises the following steps of firstly dividing a 0-10.6 GHz frequency band into four sub-frequency bands; and then taking a Gaussian derived function as a basic function in each sub-frequency band to approach FCC emission mask, and obtaining the sub-pulse with a maximum power spectrum utilization; finally, passing the obtained four sub-pulses through a group of parallel bandpass filters, adding the output sub-pulses of the bandpass filters together, and obtaining the ultra wide band pulse with a frequency range from 0 to 10.6GHz. Compared with the existing ultra wide band pulse design method, the ultra wide band pulse spectrum obtained by the method in the invention can satisfy FCC emission mask and can effectively utilize the allowable power limit value of the FCC emission mask with the frequency range from 0 to 10.6 GHz; and thus, the power spectrum utilization can be improved.

The invention provides a variable supercharged engine EGR rate feedback control method based on air inlet flowmeter information. The method comprises the steps that 1, a standard air inlet flow pulse spectrum and a target EGR rate pulse spectrum are queried to obtain standard air inlet flow and target EGR rate; 2, an EGR valve basic-opening-degree pulse spectrum is queried to obtain an EGR valve opening degree base value; 3, the target inlet flow of fresh air of an engine is calculated, the actual air inlet flow of the fresh air of the engine is measured, and an air inlet flow deviation of the fresh air of the engine is calculated; 4, an EGR valve correction opening degree pulse spectrum is queried to obtain an EGR valve opening degree correction value; 5, the sum of the EGR valve opening degree base value and the EGR valve opening degree correction value is an EGR valve opening degree target value; 6, an actual EGR valve opening degree value is measured and is regulated by using an EGR valve PID controller to make the actual value consistent to the EGR valve opening degree target value. By adopting the method, the consistency between the actual EGR rate and the target EGR rate is ensured on the basis that rapid responsiveness of an EGR system is ensured.

The invention relates to a system for controlling a femtosecond laser two-dimensional infrared spectroscopy device. The system is characterized by comprising a computer and a data collection card, wherein the data collection card receives a multi-channel pulse spectrum signal via an infrared array detector, and transmits to the computer; a control system is arranged inside the computer and comprises an electric translation stage control unit, a femtosecond pulse integration control unit, a monochromator control unit, a data analysis treatment unit and a signal real-time display unit; the electric translation stage control unit controls the electric translation stage to move according to set parameters; the monochromator control unit controls an input light slit, the grating type and a center wavelength of a monochromator; the femtosecond pulse integration control unit integrates the collected signal, accumulates for a plurality of times, and then respectively transmits to the data analysis treatment unit and the signal real-time display unit; the data analysis treatment unit processes the received spectrum signal; and the signal real-time display unit is used for displaying the signal output by the femtosecond pulse integration control unit in real time. The system can be widely applied to a control process of the femtosecond laser two-dimensional spectroscopy device.

The invention provides a method and system for increasing endurance mileage of an electric vehicle. The method for increasing the endurance mileage of the electric vehicle comprises the steps of collecting daily running information of the vehicle in a fixed driving mode; obtaining actual torque demand values at different times under a condition of same vehicle speed and throttle opening from the daily running information; conducting statistics on mean values of a series of obtained actual torque demand values so as to obtain a statistical value; and using the statistical value as an adjustingbasis to adjust a theoretical demand value corresponding to the vehicle speed and the throttle opening and output by a motor torque in a calibrated pulse spectrum, wherein the adjusted theoretical demand value is closer to the statistical value than the unadjusted theoretical demand value. According to the method and system for increasing the endurance mileage of the electric vehicle, the energy consumption of the electric vehicle per unit mileage is furthest reduced, and the endurance mileage of the electric vehicle is increased.

Light pulses can be stopped and stored coherently, with an all-optical process that involves an adiabatic and reversible pulse bandwidth compression occurring entirely in the optical domain. Such a process overcomes the fundamental bandwidth-delay constraint in optics, and can generate arbitrarily small group velocities for light pulses with a given bandwidth, without the use of any coherent or resonant light-matter interactions. This is accomplished only by small refractive index modulations performed at moderate speeds and has applications ranging from quantum communications and computing to coherent all-optical memory devices. A complete time reversal and / or temporal / spectral compression and expansion operation on any electromagnetic field is accomplished using only small refractive index modulations and linear optical elements. This process does not require any nonlinear multi-photon processes such as four-wave mixing and thus can be implemented using on-chip tunable microcavity complexes in photonic crystals. The tuning process requires only small refractive index modulations, and moderate modulation speeds without requiring any high-speed electronic sampling.

The invention provides a chirp laser pulse spectrum shaping system based on a Mach-Zehnder interferometer, and relates to the technical field of laser pulse amplification. The chirp laser pulse spectrum shaping system based on a Mach-Zehnder interferometer includes a laser emitting module and a beam splitting module, an optical length adjusting module and a beam combining module. The beam splitting module is arranged behind the laser emitting module. The laser emitting module is configured to generate a chirp laser pulse. The beam splitting module is configured to split the chirp laser pulse into multiple optical paths. The optical length adjusting module is arranged behind the beam splitting module, and is disposed in any split optical path. The optical length adjusting module is configured to adjust the optical length of the optical path. The beam combining module is arranged behind the optical length adjusting module and is configured to enable the chirp laser pulses with differentoptical lengths to converge and to emit the chirp laser pulses suffering from interference. The chirp laser pulse spectrum shaping system solves the gain narrowing of the spectrum during the amplification of the chirp laser pulses in the prior art.

The invention discloses a Kerr lens mode locking Yb: YCa4O (BO3) 3 (Yb: YCOB) all-solid-state femtosecond laser pumped by a diode. The laser comprises a pumping source, an optical coupling and focusing system, a Yb: YCOB laser gain medium, a first concave mirror, a second concave mirror, a first triangular prism, a second triangular prism, a plane reflection mirror and a plane output mirror. The central wavelength of lasers output by the pumping source is 976 nm. Kerr lens mode locking is achieved on Yb: YCOB laser crystals for the first time, mode locking pulses of 73 fs are output, and the full width at half maximum of a mode locking pulse spectrum is 19 nm. The laser has the advantages of being excellent in practicability and operability, compact in structure, suitable for repeated production and assembly and volume production and low in cost; the lasers are output in the single direction, repetition frequency is high, the pulse width of sub-100 fs magnitude is achieved, and stability and laser beam quality are high. The laser can be widely applied to the fields of national defense, industries, medical treatment, scientific research and others and has excellent application prospects and high commercial value.

The invention discloses an all-optical-fiber sub-hundred-femtosecond ultrashort pulse generation apparatus with a compact structure. The apparatus comprises a dissipation soliton oscillator, an output isolation part, a pre-compression part and an amplifying and nonlinear compression part which are connected in sequence through mono-mode optical fibers; negative dispersion is introduced to the pre-compression part; the negative chirp quantity provided by the pre-compression part is less than the positive chirp quantity of input pulse; the dissipation soliton oscillator generates pulse with relatively high energy and positive chirp, and the pulse enters the pre-compression part through the output isolation part to compress the pulse width and improve the pulse peak power, and finally, the pulse energy in the amplifying and nonlinear compression part is improved; and the pulse spectrum is widened and the pulse width is compressed through the nonlinear process to obtain the sub-hundred-femtosecond ultrashort pulse. The apparatus has the all-optical-fibre structure and relatively high resistance to external environment disturbance based on a dissipation soliton optical fibre laser in a single-wall carbon nanotube locking mode and can stably output sub-hundred-femtosecond pulse for a long time.

The invention discloses a laser diode pumping Kerr-lens mode locking Yb:(YLa)2O3 all-solid-state femtosecond laser device. Yb:(YLa)2O3 laser ceramics, a pumping source, an optical coupling focusing system, two concave mirrors, two triple prisms, a GTI reflecting mirror, a plane mirror and an output mirror are arranged. According to the device, Kerr-lens mode locking is achieved on the Yb:(YLa)2O3 laser ceramics at the first time, 170 fs of mode locking pulses are output, the half-width of a mode-locking pulse spectrum is 7.7 nm, and the average output power is 140 mW. The device has the advantages of being good in practicability and operability, compact, small and exquisite in structure, suitable for repeated production and assembling, and mass production and lower in cost, achieving single-way laser output, high repetition frequency and femtosecond magnitude pulse width, and being high in stability and light beam quality, can be widely applied to the fields of national defense, industries, medical treatment and scientific research, and has the good application prospects and commercial value.

The invention relates to a method for generating and detecting terahertz pulses in real time. According to the technical scheme, the method comprises the steps that a metallic vapor vacuum arc method is carried out on lithium niobate single crystals grown through a crystal pulling method to obtain a lithium niobate single crystal sheet with copper injected, and the lithium niobate single crystal sheet is used as a terahertz radiation source (5); laser pulses generated by a titanium sapphire laser (3) enter the terahertz radiation source (5) in an incident mode, and terahertz pulses are generated through an optical rectification method; a terahertz time-domain pulse spectrum is obtained through an electro-optical sampling method, and finally fast Fourier transformation is carried out on the terahertz time-domain pulse spectrum through MatLab software installed in a computer to obtain a terahertz frequency-domain pulse spectrum. The method has the advantages that the device is simple, cost is low, the raw materials of the terahertz radiation source are rich and easy to obtain, and the terahertz pulses are high in generation efficiency.

The invention relates to an optical phase lock-based pulse laser zero-difference coherent detection device and relates to a laser coherent detection device in the technical field of optoelectronics. According to the coherent detection device, after the local oscillator laser and the pulse echo signal laser are input into a 90-degree optical mixer, four paths of coherent optical signals with the phase difference of 0 degree, 90 degrees, 180 degrees and 270 degrees are outputted. Among the four paths of coherent optical signals, two paths of optical signals with the phase difference therebetweento be 0 degree and 180 degrees are outputted through an in-phase branch circuit and then are inputted into a laser phase-locked loop through the 4-photoelectric conversion of a first balance detector. In this way, the phase locking of the pulse signal laser and the continuous local oscillator laser is realized. The other two paths of optical signals with the phase difference therebetween to be 90degree and 270 degrees are outputted through an orthogonal branch circuit, and then pulse laser signals can be completely recovered after the photoelectric conversion of the signals through a secondbalance detector. According to the pulse spectrum width of the pulse signal laser, a corresponding narrow-band detector is selected for receiving signals. Therefore, high-sensitivity detection signalscan be obtained.

A physical method for maintaining the freshness of vegetables and fruits via the technology of the optical signal and optical signal generator are disclosed. By adopting the computer programmable pulsed scanning signal generator, it controls the light-emitting device mounted with red, green and blue light sources group to generate optical signal with pulsed or pulsed periodical scanning combined spectrum. The optical signal irradiates the fresh-cut fruits and vegetables preserved in the storage assembly at room temperature or at controlled temperature and humidity. By regulating the optical signal with periodical pulsed spectrum or pulsed scanning spectrum or periodical pulsed scanning combined spectrum, the irradiated vegetables and fruits obtain photon energy needed in light reactions of photosynthesis from the lighting environment of artificial optical signal which is in bright and dark periodic variation. The metabolism of the cellular tissue is thus recovered and maintained, and the growth inertia is kept at slow speed. It effectively prolongs the freshness state of vegetables and fruits which are preserved in the storage assembly.

The invention discloses a method for improving drivability of a finished vehicle. Corresponding throttle torque pulse spectrums are achieved by the finished vehicle according to different gears, thusthe different gears correspond to the different throttle torque pulse spectrums, and the corresponding throttle torque pulse spectrum is selected according to the current gear to control the engine running area of the finished vehicle. The method for improving drivability of the finished vehicle is economical, specifically, the corresponding throttle torque pulse spectrums are achieved according to the different gears, the engine running area can be controlled, and the high fuel consumption area on the universal characteristics are avoided to achieve the fuel saving purpose. The method for improving drivability of the finished vehicle has excellent emission performance, specifically, the corresponding throttle torque pulse spectrums are achieved according to the different gears, the enginerunning area can be controlled, and the high emission area on the universal characteristics are avoided to achieve the purpose of controlling emission.

The invention provides a phase-sensitive optical time domain reflection device and method based on frequency modulation. The method comprises the following steps: dividing laser into two paths, carrying out the synchronous modulation and output of an intensity modulator, obtaining a multi-frequency optical pulse sequence, wherein each optical pulse spectrum is composed of a fixed single frequency and a linear chirp with a non-overlapping frequency band; enabling the sequence to generate backward Rayleigh scattering signals with mutually separated frequency bands in a sensing optical fiber, and obtaining a Rayleigh scattering pattern of each multi-frequency optical pulse by using digital band-pass filters with different frequency bands; and sequentially carrying out related processing on the Rayleigh scattering patterns obtained in sequence, and finally obtaining a disturbance position and a disturbance size thereof. According to the phase-sensitive optical time domain reflection device and method based on frequency modulation provided by the invention, the problem of signal aliasing caused by the fact that a plurality of pulses are hit in a repetition period in a traditional device is solved, the detection interval time is shortened, the measurement speed is greatly improved, and the broadband large-vibration measurement capability of the system is improved.

The invention provides a method for controlling an engine EGR rate by a combined pulse spectrum, belonging to the vehicle gasoline engine control field, comprising a basic EGR rate pulse spectrum parameter and a dynamic EGR rate pulse spectrum parameter, wherein, the basic EGR rate pulse spectrum parameter is standardized by a jack horse or optimized and standardized by the jack horse and a road parameter, the dynamic EGR rate pulse spectrum parameter is generated by the self-standardization of the self-study on line of a control system and the self-optimization, and the adaptively control of the EGR rate of the gasoline engine is controlled by the control system according to a control strategy. The combined pulse spectrum control way synthesized by the self-adapting study method is adopted; therefore, the influence of the change in a controlled system and the unknown change on the engine is corrected, thereby improving the control accuracy of the open-loop control and increasing speed. The self-adapting study controls the strategy generating a dynamic pulse spectrum and advances the predictive control, thereby correcting the control lag generated by various time-lag effects and improving the timeliness of the control.