55 results about "Energy stability" patented technology

A combined radiation pulse of a predetermined energy is provided by temporally and spatially overlapping four pulses from four extra-cavity, frequency-tripled lasers. Frequency tripling is effected in each laser by a second-harmonic generating crystal followed by a third-harmonic generating crystal. One of the lasers includes a Pockels cell preceding the second-harmonic generating crystal. The third harmonic pulse from this laser is the fourth and last delivered in the sequence. The total available energy in three of the pulses is less than the predetermined energy. The cumulative integrated energy of the pulses is determined while the pulses are being delivered. When the energy is determined to have reached the predetermined value, the Pockels cell is activated to rotate the polarization plane of fundamental radiation entering the second-harmonic generating crystal, thereby terminating generation of the fourth pulse and delivering the combined radiation pulse at the predetermined energy.

There is provided an element mapping unit, scanning transmission electron microscope, and element mapping method that enable to acquire an element mapping image very easily. On the scanning transmission electron microscope, the electron beam transmitted through an object to be analyzed enters into the element mapping unit. The electron beam is analyzed of its energy into spectrum by an electron spectrometer and an electron energy loss spectrum is acquired. Because the acceleration voltage data for each element and window data for 2-window method, 3-window method or contrast tuning method are already stored in a database and accordingly the spectrum measurement is carried out immediately even when an element to be analyzed is changed to another, the operator can confirm a two-dimensional element distribution map immediately. Besides, because every electron beam that enters into an energy filter passes through the object point, aberration strain in the electron spectrometer can be minimized and higher energy stability can be achieved. As a result, drift of the electron energy loss spectrum acquired by analyzing the electron beam into spectrum can be minimized and element distribution with higher accuracy can be acquired.

A noncollinear serial beam combination device based on the stimulated brillouin scattering relates to a laser serial beam combination device, and belongs to the optical field. The noncollinear serial beam combination device based on stimulated brillouin scattering aims at overcoming the defects that the system load of superposed and coupled parallel beam combinations and backward injection seed beam combinations is not high and the back-reflection rate of SBS is low, and simultaneously aims at solving the problems that the demand of the light beam energy stability of an independent medium pool SBS parallel beam combination is high and the number of optical elements is large. The present invention comprises noncollinear brillouin magnified structure units with the number of n; wherein, each of the noncollinear brillouin magnified structure unit is composed of medium pools and optical traps; the seed beams are incident in the medium pools in a direction parallel to the medium pools, and pump beams are incident in the medium pools from the other side of the medium pools. The included angle between the seed beams and the pump beams is alpha. After the seed beams in the medium pools are magnified, the residual pump beams are incident in the optical traps. The seed beams magnified by the pump beams in the medium pools are conveyed to the next noncollinear brillouin magnified structure unit.

The invention relates to an apparatus for measuring multiple parameters of laser and belongs to the technical field of laser measurement. The apparatus is a measuring apparatus for laser, which comprises a computer, a power supply module, a reception module for a control signal, a front optical lens, a near-field optical lens, a scientific CCD, a near-field electric translation stage, a far-field electric translation stage, a photoelectric probe, a set of optical wedge plates, a set of reflectors, an attenuation slice and an energy meter. The measuring and calculating of the energy, the energy stability, the wavelength, the spectrum distribution, the pulse width, the pulse shape, the near-field light spot, the softening factor, the near-field modulation depth, the M2 factor, the divergence angle, the directivity, the output signal to noise ratio, the polarization direction, polarization degree, the beam waist location, the image transfer surface position, and the Rayleigh distance of monopulse laser can be realized through connecting the apparatus with relevant external measurement devices. The apparatus has the advantages of effectively improving measurement efficiency, calculating relevant parameters of a measured beam, and having practicality.

There is provided an element mapping unit, scanning transmission electron microscope, and element mapping method that enable to acquire an element mapping image very easily. On the scanning transmission electron microscope, the electron beam transmitted through an object to be analyzed enters into the element mapping unit. The electron beam is analyzed of its energy into spectrum by an electron spectrometer and an electron energy loss spectrum is acquired. Because the acceleration voltage data for each element and window data for 2-window method, 3-window method or contrast tuning method are already stored in a database and accordingly the spectrum measurement is carried out immediately even when an element to be analyzed is changed to another, the operator can confirm a two-dimensional element distribution map immediately. Besides, because every electron beam that enters into an energy filter passes through the object point, aberration strain in the electron spectrometer can be minimized and higher energy stability can be achieved. As a result, drift of the electron energy loss spectrum acquired by analyzing the electron beam into spectrum can be minimized and element distribution with higher accuracy can be acquired.

The invention provides an energy stability-domain building system and method for a power system. The energy stability-domain building system comprises a data acquisition module, a system dynamic-equation generating module, a damping energy solution module, an energy stability-domain building module and a result output module, wherein the data acquisition module is used for acquiring network structure parameters, and the frequency and the power angle of an engine in the system; the system dynamic-equation generating module is used for obtaining the dynamic equation of the system; the damping energy solution module is used for calculating the damping energy accumulated in the armature reaction of the engine of the system during one cyclic wave oscillation; the energy stability-domain building module is used for building an energy stability domain of the power system, which reflects the dynamic stability and the transient stability of the system; the result output module is used for outputting the energy stability domain of the power system. Through the adoption of the energy stability-domain building system and method for the power system, provided by the invention, the static stability and the dynamic stability of the system can be reflected, and the accuracy is higher.

The invention discloses an automatic temperature control system for an excimer laser. The excimer laser is provided with a first cavity module and a second cavity module which comprise discharge cavities, magnetic compressors and solid switches. The temperature control system comprises a cooling system for cooling the two magnetic compressors, a cavity temperature control system for controlling temperatures of the two discharge cavities and a cooling system for cooling the two solid switches. By means of the automatic temperature control system for the excimer laser, gas temperatures in the discharge cavities can be controlled automatically and accurately, and accordingly, the laser can be guaranteed to have high energy conversion efficiency and energy stability, the engine heating time can be reduced greatly, and the laser service life is increased.

The invention discloses a steady-state energy-supplementation control strategy of hybrid high voltage DC circuit breaker. According to the invention, through a reasonable switch action time sequence, capacitor voltage of an improved full-bridge sub module can be made to fluctuate within a manually set threshold value range, so that energy stability is ensured and influence on power supply reliability of a drive circuit of the full-bridge sub module due to violent fluctuation of the capacitor voltage is prevented. Besides, since a load transfer switch and a main circuit breaker get energy through capacitors of sub modules of themselves respectively, external power supply is not needed, so that problems of insulation of voltage resistance in projects are avoided; design, manufacture and construction difficulties are reduced; and application of the circuit breaker typology in a high voltage DC power grid is facilitated.

The invention discloses a temperature control method and a system for an excimer laser, wherein the excimer laser comprises a discharging cavity, a plurality of temperature detectors and a plurality of temperature control devices. When the discharging cavity works, heat is generated. The plurality of temperature detectors are used for detection of temperature at a plurality of positions relative to the temperature of the discharging cavity. The plurality of temperature control devices are used for cooling or heating the discharging cavity. Provided is a neural network proportion integration differentiation (PID) controller. The neural network PID controller receives temperature signals detected by a plurality of temperature sensors, and respectively regulates the temperature control devices according to the plurality of temperature signals, and enables the temperature of the discharging cavity to reach the required temperature. The temperature control method and the system for the excimer laser are capable of rapidly and accurately measuring the temperature of the discharging cavity of the excimer laser and capable of improving temperature stability of the system, and therefore higher power conversion efficiency and power stability of a laser are ensured.

The invention discloses a multi-pass laser amplifier, which consists of a near field shaping module I, an isolation and input-output module II, a multi-pass amplifier cavity module III and a wave-front measurement module IV, wherein the near field shaping module I shapes a near field of an input light spot; the isolation and input-output module II completes the input and the output of main laser; the multi-pass amplifier cavity module III mainly carries out high-quality amplification on the main laser; the wave-front measurement IV measures the wave front of output laser, and cooperates with a wave-front corrector to complete the control on the wave front. By using the multi-pass laser amplifier, the laser amplifier which is large in caliber, controllable in gain and good in the quality of an output light spot can be realized; meanwhile, the stability of the output energy of the laser amplifier can be improved; the multi-pass laser amplifier is particularly applicable to the design of a high-power solid laser amplifier under high-gain and repetition-frequency work.

The embodiments of the invention provide a frame loss compensation processing method and a device. The method includes the following steps: determining whether an ith frame is a lost frame through a lost frame marker bit; and if the ith frame is a lost frame, estimating the spectrum frequency parameter, the pitch period and the gain of the ith frame according to at least one of the inter-frame relationship and the intra-frame relationship of N frames before the ith frame, wherein the inter-frame relationship of the N frames includes at least one of the correlation and the energy stability of the N frames, and the intra-frame relationship of the N frames includes at least one of the correlation and the energy stability of the N frames. The parameters of the ith frame are determined according to the signal correlation and the energy stability of the N frames and the correlation and the energy stability of signals in each frame. As the relationship between signals is considered, the estimated parameters of the ith frame are more accurate. Therefore, the quality of decoded speech signals is enhanced.

The invention relates to a doubly-fed fan control parameter optimization method and system based on an energy stability domain, belongs to the technical field of fans, and solves the problem of stableoperation of a wind power grid-connected system at the present stage. The method comprises the following steps: establishing a wind power grid-connected system energy stability domain and determiningthe stability boundary; calculating the energy distance from the current operating point to the boundary of the energy stability domain and constructing the energy distance stability condition of a post-disturbance system, wherein the energy distance is the distance from the operating point of the wind power grid-connected system to the stability boundary along the disturbance direction for a period of time after the disturbance occurs; and establishing the objective function constraint conditions by aiming at the energy distance stability and optimizing and outputting the key control parameters of the doubly-fed wind turbine by using the improved plant simulation growth algorithm. The power angle stability level of the system can be effectively improved, and the oscillation of the grid-connected system can be suppressed in a certain range.

A seed injection single longitudinal mode double-pulse laser and a control method include four parts: an L-shaped resonant cavity, a pump source, a seed source, and a circuit control system. The laser of the invention can guarantee 100% single longitudinal mode output, and has the characteristics of high energy stability, high frequency stability, high pointing stability, strong anti-interference ability, long service life and compact structure.

The invention relates to a dynamic energy stability evaluating method and system for a doubly-fed induction generator grid-connected system and belongs to the technical field of wind power generationsystems. With the dynamic energy stability evaluating method and system for the doubly-fed induction generator grid-connected system of the invention adopted, the problem of the low accuracy of the stability evaluation of an existing wind turbine generator grid-connected system can be solved. The method comprises the following steps that: when secondary synchronous oscillation occurs on the doubly-fed induction generator grid-connected system, the voltage and current instantaneous values of an induction generator grid-connected point and a series compensation position are acquired; the dynamicenergy of the doubly-fed induction generator grid-connected system is obtained based on the voltage and current instantaneous values of the induction generator grid-connected point and the series compensation position; the dynamic energy of the doubly-fed induction generator grid-connected system in integer periods is collected, and non-periodic components are extracted from the dynamic energy; and if the change rate of the non-periodic components is positive, the doubly-fed induction generator grid-connected system has a negative damping characteristic, and oscillation diverges, and otherwise, the doubly-fed induction generator grid-connected system has a positive damping characteristic, and oscillation converges. With the method and system of the invention adopted, the stability of thedoubly-fed induction generator grid-connected system can be accurately and effectively evaluated.

The invention relates to a method for improving the stability of ultra-short laser frequency-doubling energy. The method is characterized by comprising the following steps: (a) obtaining a curve of triple frequency conversion efficiency relative to the light intensity of fundamental-frequency light; (b) obtaining a range of light intensity corresponding to a decline part of the curve according to the decline part; and (c) adjusting the basic parameters of the fundamental-frequency light to enable the light intensity of the fundamental-frequency light to be within the range of light intensity. According to the invention, by selecting fundamental laser parameters (pulse energy, pulse width, and beam aperture) and crystal parameters, the frequency tripling process is enabled to work in an appropriate position of the decline part of the curve of triple frequency conversion efficiency, and thus the energy stability of triple-frequency light is significantly improved. The passive stability improving method breaks through the limit that the traditional triple-frequency light energy jitter is about three times the fundamental-frequency light energy jitter, the energy stability of triple-frequency light is obviously better than that of fundamental-frequency light, and the smoothness of transverse distribution and longitudinal distribution of triple-frequency light can be significantly improved.

A preparation method of a low-temperature poly-silicon thin film transistor comprises the following steps of forming a first amorphous-silicon layer on a substrate; forming doping layers on regions, corresponding to a source doping layer and a drain doping layer to be formed, on the first amorphous-silicon layer; carrying out laser irradiation on the substrate formed with the first amorphous-silicon layer and the doping layers so as to convert the first amorphous-silicon layer to a first poly-silicon layer; forming a second amorphous-silicon layer on the first amorphous-silicon layer and the doping layers; and carrying out laser irradiation on the substrate formed with the second amorphous-silicon layer to form a second poly-silicon layer, the source doping layer and the drain doping layer. According to the preparation method of the low-temperature poly-silicon thin film transistor, the first poly-silicon layer also can be taken as a second amorphous-silicon thin film to be converted into a grain structure induction layer of the poly-silicon layers, the requirements of excimer laser pulse energy stability and light beam energy density uniformity during preparation of the low-temperature poly-silicon thin film can be effectively reduced, and the problem of non-uniform display caused by laser annealing processing can be effectively solved.

The invention relates to a low-temperature Yb: yttrium aluminum garnet (YAG) regenerative amplifier. The low-temperature Yb: YAG regenerative amplifier consists of six parts, namely a pulse signal optical coupling system, an isolation system, an optical regenerative amplifying cavity, an electro-optical switch system, a low-temperature vacuum system and a pumping system; a sheet Yb: YAG crystal is used as a gain medium; by adoption of a pumping manner that a semiconductor laser device is back to the end face, the pulse signal light achieves an amplified gain effect due to temperature-controllable refrigeration of liquid nitrogen on the Yb: YAG crystal; and the stability of the amplified output energy is improved. By the low-temperature Yb: YAG regenerative amplifier, amplification of a pulse signal with high repetition frequency, high stability, high gain and high optical quality is realized.

The invention discloses a self-stabilization passively Q-switched laser. The self-stabilization passively Q-switched laser comprises a resonant cavity and a laser pulse feedback device; the resonant cavity is composed of a gain medium, a saturable absorber and an output cavity mirror; the resonant cavity absorbs energy provided by a laser pumping source, and is used for generating and outputting passively Q-switched pulse laser; the laser pulse feedback device is composed of an attenuator, an optical fibre delayer and a total-reflection mirror; and the laser pulse feedback device is used for feeding back the resonant cavity output laser pulse intercepted by a spectroscope to the resonant cavity after delaying the resonant cavity output laser pulse for a certain time and attenuating a certain energy. The self-stabilization passively Q-switched laser disclosed by the invention has the advantages that: the passively Q-switched pulse output by the laser is difficultly influenced by spontaneous radiation noise of the gain medium and pump light intensity fluctuation; and the pulse time interval and the energy stability can be effectively improved.

The invention provides a current control method applicable to bifurcate modular multilevel converters. A first alternating-current port current control module uses two PIs to control the current under a synchronous rotating coordinate system, and outputs a d-q coordinate system component of the reference voltage at a first alternating-current port; a second alternating-current port current control module uses two PIs to control the current under a synchronous rotating coordinate system, and outputs a d-q coordinate system component of the reference voltage at a second alternating-current port; an alternating-current reference voltage decomposition module decomposes the reference voltages of the first and second alternating-current ports, and outputs the alternating-current reference voltage of each branch bridge arm; and a branch reference voltage generation module synthesizes the alternating-current reference voltage of each branch bridge arm and a corresponding direct-current reference voltage, and outputs a reference voltage of each branch bridge arm for modulation. A good steady-state control effect is achieved for bifurcate MMCs, the three-phase current is controllable, and the energy stability of each branch bridge arm is ensured.

The invention belongs to the power system stability analysis and control field and particularly relates to a time-varying power system stability analysis system and method based on the lasalle invariance principle. The system comprises a non-linear model generation module, an LMI solution module, a Lyapunov function construction module and a transient stability domain generation module which are sequentially connected. The method comprises steps that a multi-machine power system non-linear dynamics model is constructed, and a non-linear model reasonable boundary is described; a construction problem of a power system Lyapunov function is converted into a feasible solution problem of a set of linear matrix inequality, and a Lyapunov function cluster is constructed; a multi-element state quantity-energy stability boundary is constructed, and a transient stability domain capable of visually reflecting a system state and carrying out safety early warning is established. The method is advantaged in that problems that an energy function of a standard construction method can not be given in researches in the prior art and conservatism of describing a stability domain is relatively high are effectively solved.

The invention discloses a non-collineation serial beam grouping method and device based on excited brillouin scattering, relates to a serial beam grouping technique of laser, and aims to solve the problem that in serial beam grouping, a plurality of light beams cannot be further grouped when amplification light energy density reaches a generation threshold of a nonlinear effect such as excited brillouin scattering of a medium or exceeds a breakdown threshold of the medium. Seed light is fed to be in front of each medium pond, beams are firstly amplified through a cylindrical lens beam amplification system, and the outgoing end of a final medium pond is provided with a cylindrical lens beam shrinkage system for shrinking the beams, so that the problems that nonlinear effects such as excited brillouin scattering are generated and the medium has a breakdown threshold can be avoided; in addition, the structure is simple, the amplification efficiency is improved, the energy stability requirements of pumping light are low, different loading capabilities can be obtained by using the cylindrical lens beam amplification system with different beam amplification ratios, the shapes of outgoing light spots are identical to those of light before being fed, and the method and the device are applicable to fields such as inertial confinement fusion, impact intensification, optoelectronic countermeasure, laser radar and optical parametric oscillator pumping.

The invention provides a combined light source system for photodynamics therapy. The system comprises a therapy head front cover and a therapy head back cover; a transmittance protection glass plate,an optical shaping lens array, an optical shaping lens array mounting plate, an irradiation light source integration plate and an irradiation light source cooling device are mounted between the therapy head front cover and the therapy head back cover in sequence; as the optical shaping lens array is adopted, the irradiation power density is high, the irradiation area is large, the output energy isstable, the irradiation surface energy density uniformity is good, and the irradiation light wavelength is stable; a laser distance measuring probe is provided for measuring the distance from the combined light source system to a therapy part, so that the therapy quality is guaranteed, and the problems of burn of the patient skin due to nearer distance and influence on the therapy effect due to farther distance are prevented; the irradiation light source cooling device is provided for cooling to prevent burnout of an irradiation light source; and a laser is indicated to emit converted indication light rays for precisely positioning the therapy part.

The invention relates to a system and a method capable of realizing energy stability of injected laser. The system is connected with an external injection fiber and comprises a first light split unit, a Lambda / 2 wave plate, a second light split unit, an energy monitoring device, a delay device, an optical rotation device, a third light split unit and an electric control device, wherein the input light from the injection fiber is changed to a first horizontal polarized light by the first light split unit, is rotated at a preset angle Theta by the Lambda / 2 wave plate and is then split into a first polarized light and a second polarized light by the second light split unit, the first polarized light enters the energy monitoring device, the delay device receives and transmits the second polarized light in a delayed manner, the electric control device receives the energy E monitoring of the first polarized light and generates an optical rotation angle Beta according to the energy E monitoring, and the optical rotation device carries out optical rotation according to the angle Beta; and the third light split unit receives the second polarized light after optical rotation and outputs a second horizontal polarized light. According to the system and the method, the stability of pulse laser outputted by the system along with the time change is ensured, and the stable gain of the laser pulse is further realized.

The invention relates to an energy stability domain determination method and system for a doubly-fed wind power grid-connected system, belongs to the technical field of fan grid-connected stability domain research, and solves the problem of stable operation of the wind power grid-connected system at the present stage. The method comprises the following steps: selecting a certain operation point with positive total damping energy from a stable domain parameter space as an initial search point, and injecting active power of all nodes in the doubly-fed wind power grid-connected system to form thestable domain parameter space; obtaining a basic search point set in a feasible search range by taking the initial search point as a starting point; determining unstable search points in the basic search point set; establishing a connection line between an initial search point and each unstable search point, and carrying out critical point search to obtain a critical point set; obtaining corresponding total damping energy according to the node active power injection of each critical point in the critical point set, forming an energy stability domain boundary by the total damping energy obtained by all the critical points, and obtaining the energy stability domain of the double-fed fan grid-connected system.

The invention provides an excimer laser pulse energy stability control method. The excimer laser pulse energy stability control method comprises the steps: firstly obtaining an energy measurement value of an n-th pulse in a pulse sequence; calculating a difference value between the energy measurement value and an energy set value; calculating a discharge voltage value of a next pulse according toa first mathematical model by taking a z-th pulse of the sequence as a demarcation point when n is a positive integer smaller than z; calculating the discharge voltage value of the next pulse according to a second mathematical model when n is an integer greater than z-1; and finally generating a next pulse according to the calculated discharge voltage value. The control method can effectively control the energy overshoot phenomenon in each pulse sequence and the stability of all pulse energy in one pulse sequence. The control system based on the control method comprises a high-voltage discharging module, a laser cavity, a laser parameter measuring module and an energy stability controller. The system is simple in structure, and the energy stability control over the system can be achieved only by the separation of a small amount of energy.

The invention relates to a method and a system for detecting dissipated energy stability of a direct-drive permanent magnet wind power system, and belongs to the technical field of wind power generation. The method comprises the following steps: S1, acquiring operation data of the direct-drive permanent magnet wind power system; S2, calculating dissipated energy of the direct-drive permanent magnet wind power system according to the operation data; and S3, carrying out stability detection on the system according to the dissipated energy of the direct-drive permanent magnet wind power system. The wind power system dissipated energy model of phase-locked loop control, current loop control and parallel SVG control links of a grid-side converter is built; the stability of the direct-drive windpower system is detected on the basis of the dissipated energy model; and the real-time detection of the stability of the wind power grid-connected system is realized.

The invention discloses a laser pulse energy stabilizing device and method and belongs to the technical field of lasers. The device is divided into a main optical path and a sampling optical path. The main optical path is provided with a Pockels cell electro-optical switch. The sampling optical path is provided with a photoconductive switch. The method includes the steps of first detecting laser pulse energy fluctuation and then quickly discharging driving voltage applied to both electrodes of the Pockels cell electro-optical switch through the photoconductive switch. The laser pulse energy stabilizing device and method achieves energy stability control of the same laser pulse through the laser pulse energy fluctuation, has a self-stabilizing characteristic and does not cause laser pulse time waveform distortion.

The invention discloses a low-air-pressure excited Raman light source system apparatus. The apparatus comprises an ultraviolet pumping laser, a focusing lens, an intelligent air pressure sensing apparatus, an inflating control valve, a low-pressure Raman tube, an impurity filtering apparatus and a laser collimator, wherein the ultraviolet pumping laser emits laser to pass through the focusing lens to be focused into the low-pressure Raman tube and to finally emit to the laser collimator, wherein the low-pressure Raman tube is provided with the intelligent air pressure sensing apparatus for monitoring the air pressure in the low-pressure Raman tube, the inflating control valve used for supplementing air pressure and the impurity filtering apparatus used for removing impurities from air; and the intelligent air pressure sensing apparatus is electrically connected with the inflating control valve. By adoption of low-air-pressure design, the safety of the Raman tube apparatus can be improved; by virtue of design of the intelligent air pressure sensing apparatus and the inflating control valve, constant air pressure in the Raman tube can be ensured, and laser energy stability can be improved; and by virtue of the impurity filtering apparatus, the effective service cycle of the Raman tube is prolonged.

The invention discloses a green wind-energy agricultural greenhouse which structurally comprises a greenhouse device, a greenhouse body, a wind energy device, a fan blade, a rotating shaft, a wind-driven generator, a wind-energy storage battery and a steam generator, wherein the fan blade is arranged on the wind-energy device, the rotating shaft is arranged behind the fan blade, the wind-driven generator is arranged under the rotating shaft, the fan blade is in rotary connection with the wind-driven generator through the rotating shaft, the wind-energy storage battery is arranged on the lateral side of the wind-driven generator, the steam generator is arranged behind the wind-energy storage battery, and the steam generator is fixedly connected with the wind-driven generator through the wind-energy storage battery. According to the green wind-energy agricultural greenhouse disclosed by the invention, a solar cell panel can be arranged to be matched with the wind-energy device to improveenergy source diversity; a solar storage battery and the wind-energy storage battery are in serial connection, so that energy stability is improved; by means of arranging a steam divergence plate with divergence holes, a steam divergence efficiency is improved; the green wind-energy agricultural greenhouse has the advantages of simple structure and easiness in being achieved.