170 results about "Dual pulse" patented technology

The invention relates to scanning pulsed laser systems for optical imaging. Coherent dual scanning laser systems (CDSL) are disclosed and some applications thereof. Various alternatives for implementation are illustrated, including highly integrated configurations. In at least one embodiment a coherent dual scanning laser system (CDSL) includes two passively modelocked fiber oscillators. The oscillators are configured to operate at slightly different repetition rates, such that a difference δf_r in repetition rates is small compared to the values f_r1 and f_r2 of the repetition rates of the oscillators. The CDSL system also includes a non-linear frequency conversion section optically connected to each oscillator. The section includes a non-linear optical element generating a frequency converted spectral output having a spectral bandwidth and a frequency comb comprising harmonics of the oscillator repetition rates. A CDSL may be arranged in an imaging system for one or more of optical imaging, microscopy, micro-spectroscopy and/or THz imaging.

A method is described for laser scribing or dicing portions of a workpiece using multi-source laser systems. In one embodiment, a first laser melts portions of the workpiece prior to a second laser ablating the portions of the workpiece.

The invention relates to a dual-pulse hydraulic oscillator for well drilling, and belongs to the technical fields of petroleum and natural gas exploration and well drilling tools. The dual-pulse hydraulic oscillator consists of an oscillation short section assembly and a power short section assembly, and is characterized in that the oscillation short section assembly consists of a spline mandrel, a connection sleeve, a pressure converter, an oscillation shell and the like; the power short section assembly comprises a pressing sleeve and a turbine shaft; a sealing piece is mounted between the spline mandrel and the connection sleeve; the connection sleeve is connected with the oscillation shell; the lower end of the turbine shaft is connected with the power short section assembly; the pressing sleeve at the upper end of the power short section assembly is connected with the oscillation shell; the lower end of the pressing sleeve is connected with a power shell; the turbine shaft is mounted at the center of the power shell; a straightening bearing, a turbine stator, a turbine rotor, two groups of movable valves and fixed valves, a sleeve, a flow division ring, a flow division sleeve and a thrust bearing are mounted on the turbine shaft in sequence from top to bottom. Radial swinging is avoided; under low flow, higher axial vibration with higher frequency can be realized; the friction resistance is low, so that effective drilling pressure is increased, and the mechanical drilling speed is increased.

The invention belongs to the technical field of power electronic device measurement and particularly relates to a device and a method for dynamic characteristic measurement of an IGBT. The device mainly comprises a voltage regulator, a transformer, a rectifier bridge, a bus capacitor, a discharge resistor, a first relay, a second relay, a main control panel, an auxiliary control panel, a protection circuit, an IGBT power module, a load inductor, a current sensor, a shielding box and an oscilloscope. Firstly, the first relay is switched on, the second relay is disconnected, the voltage regulator is zeroed after being adjusted to be at the voltage to be detected, and the first relay is disconnected; secondly, electrification is implemented, and the oscilloscope obtains a dual-pulse signal, IGBT two-end voltages and collector electrode current waveforms. The crosstalk of different signals, interference of a space magnetic field on measured signals and other factors are excluded, high-accuracy dynamic process waveforms can be obtained, and the device and the method have good reproducibility on delay and overshoot of voltage and current signals. The load inductor with a tap enables the circuit to be adjustable, and the device and the method can be used for measurement of different devices.

A medical laser device is described that generates a laser beam controllable with presets as to pulse duration, pulse repetition rate, power and energy per pulse. The device also provides presets with respect to water and air outputs. Parametric values for power, pulse duration, pulse repetition rate, and energy per pulse as well as for water and air settings may be programmed by an end user and stored as presets.

The invention discloses a single-light-source dual-wavelength LIBS (laser-induced breakdown spectroscopy) measurement device and method. The device mainly comprises a pulsed laser device, a frequency multiplying crystal, a light splitter, a first total reflector, a second total reflector, a light shutter, a spectrograph and a synchronous delay controller, wherein laser generated by the pulsed laser device passes through the frequency multiplying crystal, and then is divided into fundamental frequency light and frequency multiplying light, and is irradiated to the light splitter; the frequency multiplying light is reflected by the first total reflector, and is vertically irradiated to the surface of a to-be-detected sample; the fundamental frequency light passes through the light shutter, then is reflected by the second total reflector, and then is irradiated above the surface of the to-be-detected sample by 1-5mm in parallel; spectrum signals generated by a plasma stimulated from the to-be-detected sample are converged to an optical fiber collecting head, and are transmitted to the spectrograph. The single-light-source dual-wavelength LIBS measurement device provided by the invention has the advantages of simple structure, compact volume and low price while achieving dual-pulse LIBS high detection sensitivity, and can be widely applied to the technical field of laser diagnosis and spectrum analysis.

A method for controlling power to an electrical load using dual pulse width modulation (PWM) to minimize in-rush current to the electrical load, such as a heater element. An output from a power source, supplying an alternating current, is modulated by a first PWM control signal to provide a first modulated power level to the electrical load. The first modulated power level is modulated by a second PWM control signal to control power supplied to the electrical load at the first modulated power level. The first PWM control signal operates to control the number of half cycles of current in order to provide one-third, two-thirds or full cycle power. The second PWM control signal operates to define a duty cycle and period for providing the power defined by the first PWM control signal to the electrical load.

The invention discloses a preparation technology for a dual-pulse electrodeposition based graphene/nickel based composite coating. The technology includes the steps of: subjecting a plated sample to sand paper grinding and polishing treatment, and conducting ultrasonic cleaning; preparing grapheme by a chemical reduction method or liquid phase plasma method; adding the prepared graphene into a plating solution, and preparing a graphene/nickel based composite coating by dual-pulse electrodeposition. The dual-pulse electrodeposition method adopts an intelligent multi-set commutation pulse electroplating power supply, the anode is a nickel plate, the cathode is a to-be-plated sample, and they are placed on the left and right, mechanical stirring is adopted for stirring in the electroplating process , and the content of graphene added into the plating solution is 0.05-0.4g/L. With the grapheme provided by the invention, the average grain size of the composite coating is reduced, and the composite coating hardness is greatly improved compared with the matrix and the pure Ni coating, and antifriction performance and wear resistance are excellent and can meet the performance requirement of carbon steel for frictional wear under different working conditions. The technology can be applied to aerospace, machinery, automobile and other fields.

The invention discloses a method for quantitatively analyzing core slice visualized displacement. The method includes the following steps: firstly, the core slice is saturated with to-be-displaced medium; a displacing liquid tank is filled with displacing liquid; a valve is opened, and the flow is adjusted, wherein the micro flow in the system is read by a micro photoelectric meter; the focal length and aperture of a micro lens are adjusted, and the laser spot of a dual-pulse laser is adjusted to ensure that a clear image of the pore in the core slice is formed in a computer; when the gas-liquid two-phase interface or the liquid-liquid two-phase interface appears at the pore throat of the core slice, a synchronizer controls the dual-pulse laser and a CCD camera to work simultaneously, and a computer program determines and reads the displacements of two consecutive gas-liquid two-phase interfaces or liquid-liquid two-phase interfaces on the basis of correlation theories; within the given time interval, the speed and direction of the two-phase interface at the pore throat are calculated. The method provided by the invention can accurately measure the speed and direction of the gas-liquid or liquid-liquid displacement two-phase interface at the pore throat in a real core, and can provide preferable technical parameters for the research on improving the recovery ratio of oil fields.

The invention provides a single-shot laser pulse detection device. The single-shot laser pulse detection device comprises a detection light path for transmitting baseband detection light pulses, a reference light path for transmitting frequency-doubled reference light pulses, a dual-pulse generator for obtaining dual-pulses having a first time delay and transmitted collinearly along the reference light path, a light pulse converter for converting the dual-pulses into a series of dual-pulse form sub-pulses mutually delayed in time, separated from each other in space and propagated in parallel basically, a pulse stretcher for translating each frequency component of the baseband detection light pulses so as to stretch in the time domain, a dispersor for separating the frequency components in the baseband detection light pulses in space, and a plane detector for generating third-order mutual-correlation pulse signals from the baseband detection light pulses and the sub-pulses from the dispersor. The single-shot laser pulse detection device is capable of accurately measuring the waveform of the femtosecond petawatt lase pulses and solving the problem of difficult diagnosis of ultrafast and ultrastrong pulses large in dynamic range.

Systems and methods for performing Raman spectrometry wherein a Raman spectroscopy system is mounted on a vehicle for on the move contaminant analysis. The system is configured to interrogate a target with a laser at a predetermined pulse repetition frequency (PRF), wherein during each PRF cycle, defined as 1/PRF, the laser is dual pulsed at a first wavelength and at a second wavelength. Raman spectra are collected and used to identify the target by matching a Raman signature with a given collected Raman spectra.

The invention discloses an electrical field assisted writing magnetic tunnel junction unit and a writing method thereof. The electrical field assisted magnetic tunnel junction unit is provided with a dual-barrier structure and comprises a first electrode layer and a first magnetic layer, a first insulation tunneling layer, a second magnetic layer, a first metal layer, a second insulation layer and a second electrode layer which are sequentially formed on the first electrode layer, the first magnetic layer is a reference layer RL, the first insulation layer is a tunneling layer I, the second magnetic layer is a free layer FL, the first metal layer is a non-magnetic metal layer NM, and the second insulation layer is a dielectric layer I*; when voltage is applied to the two ends of the magnetic tunnel unit, an electric field is introduced to an I/FL interface and an FL/NM interface of the two insulation layers, so that interface magnetic anisotropy of the I/FL is controlled, and the interface magnetic anisotropy of the FL/NM is controlled. Continuously-applied dual pulses are applied to the writing method, the size of the magnetic anisotropy can be reduced by means of the applied electric field during writing, thus, the writing difficulty is reduced, and the power consumption of the device is greatly reduced.

The invention relates to a Brillouin optical-time-domain analyzer based on a coherence dual-pulse pair sequence technology and a method for restraining common-mode noise by utilizing the same, belongs to the field of optics, and solves the problems that a traditional Brillouin optical-time-domain analyzer is low in spatial resolution, long in measuring signal time and low in signal-to-noise ratio. A laser is adopted, an upper branch of light divided by an optical-fiber coupler I is used as pump light, pulse pairs with different pulse widths can be periodically generated by a field-programmable logic array in a programming manner, and the pulse pairs are continuously and optically modulated to form a coherence pulse pair sequence through a photoelectric modulator; a lower branch provides detection light, the detection light enters a photoelectric modulator after a polarization state is adjusted, upper marginal frequency light and lower marginal frequency light which having the frequency difference of Brillouin frequency shifting gamma B are generated on the basis of carrier light, the pump light consisting of the coherence pulse pair sequence and the modulated detection light has a Brillouin scattering phenomenon in a sensing optical fiber, and two Brillouin signals are detected by a photoelectric detector. The Brillouin optical-time-domain analyzer and the method are suitable for restraining the common-mode noise.

The invention provides a dual-pulse flash Raman method and system representing the thermophysical property of a two-dimensional nanomaterial. The dual-pulse flash Raman method for representing the thermophysical property of the two-dimensional nanomaterial comprises the following steps: (1) acquiring temperature rise data of a sample through heating pulse laser and detection pulse laser which aredifferent in wavelengths and are the same in pulse period; (2) determining the thermophysical property parameters of the sample based on the temperature rise data. According to the method provided bythe invention, the sample is heated with the heating pulse laser or detected with the detection pulse laser at different time periods, so that measurement errors are avoided in the absence of focusing; the influence of heating power on the measurement accuracy can be avoided by adopting the heating pulse laser and the detection pulse laser separately, so that the thermophysical property parametersof the sample can be represented by the method with higher accuracy and higher sensitivity.

The invention relates to a dual-pulse cyanide-free gold plating process. The parameters of the dual-pulse plating are as follows: the frequency of positive pulse is 700-1,000Hz, the time is 50-100ms, the duty cycle is 10-20%, and the current density is 0.3-0.4; the frequency of negative pulse is 700-1,000Hz, the time is 20-80ms, the duty cycle is 5-10%, and the current density is 0.03-0.04A/dm<2>. By adopting the method, the obtained plating has the advantages of fine grain, uniform thickness distribution of the plating, low porosity, rare discoloration, high hardness and strong corrosion resistance.

The invention belongs to the technical field of LIBS (laser induced breakdown spectroscopy) detection, and particularly provides an electrostatic assistance enhanced LIBS device for detecting heavy metal elements in sewage. The electrostatic assistance enhanced LIBS device comprises an incidence unit, a spectral signal receiving unit, a sewage flow velocity control unit and a data analysis unit, wherein the incidence unit comprises a YAG laser, an energy attenuation system and lenses; the spectral signal receiving unit comprises a probe, an optical fiber and a spectrometer. Compared with the traditional LIBS device, an electrostatic assistance enhanced LIBS spectral signal unit and a peristaltic pump are added to control the sewage flow velocity control unit, the intensity of acquired LIBS spectral signals is about two times higher than that of the traditional LIBS spectral signals, and the detection sensitivity is increased by two times; the electrostatic assistance enhanced LIBS device not only has the advantages of rapidness, online and in-situ detection and the like of the traditional LIBS, but also has the characteristic of improvement of the intensity of the LIBS spectral signals, compared with a DP-LIBS (dual pulse laser Induced breakdown spectroscopy) technology, the detection system adopts simple equipment, the operation is easy, the cost of a laser system and the complexity of an optical system are reduced, and the device has higher practicability.

The invention discloses a control system integrating elevator control, driving and energy feedback. The control system comprises an elevator logic control module, an elevator motor motion control module and an energy feedback module, wherein the elevator logic control module is used for elevator collective selective control, parameter testing and storing, elevator fault clearing and system self-checking and processing; the elevator motor motion control module is used for detecting the speed of an elevator motor, detecting a motor electric angle, generating an elevator running curve and controlling the elevator speed, acceleration and torque; the energy feedback module adopts dual pulse-width modulation (PWM) control technology; a controlled reactor is arranged between the input end of a three-phase power supply and a first intelligent power module (IPM); and the input current of an elevator and the current and rotating speed of a driving motor are calculated accurately so as to fulfill the aims of accurately controlling the elevator speed and acceleration and feeding energy back to a power grid. An energy-saving elevator control system can be realized due to the adoption of the control system.

A method and apparatus for thrust vectoring a flight vehicle during homing are disclosed. The flight vehicle includes a body; a plurality of attitude control mechanisms on the body; a multi-pulse motor housed at least partially in the body; and a control unit housed in the body. The control unit generates signals controlling an actuation of the attitude control mechanisms and the multi-pulse motor to initiate a follow-on burn of the multi-pulse motor to effect a maneuver directed by the actuation of the attitude control mechanisms. The method includes conserving a second burn of a dual pulse motor until target acquisition; acquiring a target; actuating a attitude control mechanism for the flight vehicle to alter the flight vehicle's heading; and initiating the second burn.

The invention discloses an integrated dual-pulse solid engine soft interlayer, and relates to the technical field of dual-pulse solid rocket engines. The designed integrated dual-pulse solid engine soft interlayer comprises a cone, a sleeve and a connecting sleeve, and the cone comprises an ethylene propylene diene monomer layer and a carbon cloth layer; the sleeve comprises an ethylene propylenediene monomer layer, a carbon cloth layer and a carbon fiber winding layer; and one end of the connecting sleeve is connected with an ignition device, and the other end of the connecting sleeve is connected with the end, away from the cone, of the sleeve. Pulse isolation of a dual-pulse engine is achieved, integrated forming can be achieved through bonding of the cone and a first-second pulse heat-insulating layer as well as connecting and sealing of the connecting sleeve and the ignition device, an integrated forming technology is simplified through the method, the negative mass can be effectively decreased, and the engine mass ratio is increased.

The present invention discloses a pulse combination femtosecond-nanosecond laser processing system and processing method. The system comprises a femtosecond-nanosecond dual-pulse laser system, a monitoring system, a laser working system and a power supply system. The femtosecond-nanosecond dual-pulse laser system generates femtosecond-nanosecond dual-pulse laser with pulse delay and transmits thefemtosecond-nanosecond dual-pulse laser to the laser working system to process workpieces. The monitoring system is positioned between the femtosecond-nanosecond dual-pulse laser system and the laserworking system to detect the real pulse delay of the femtosecond-nanosecond dual-pulse laser. The power supply system supplies all the above systems with power. Processing efficiency of semiconductormaterials is largely improved, the femtosecond-nanosecond dual-pulse laser waveform with a certain pulse delay, focusing conditions of laser spots, and processing processes can be observed in real time, and precision of the processing and processing quality of the semiconductor materials are ensured.