31 results about "Composite pulse" patented technology

The invention relates to the technical field of medical instruments, in particular to a magnetic control pulse type pelvic floor nerve muscle stimulator and a parameter optimization system thereof. Comprising a host, a dynamic layered pulse waveform generation technology module, a multi-target reinforcement learning parameter optimization module, a multi-modal biofeedback fusion and VR enhancement module, and a flexible wearable stimulation array and ultrasonic targeting module. The system has the advantages that real-time data and deep learning are achieved, and personalized precise treatment is achieved, in the actual use process, the dynamic layered pulse waveform generation technology module predicts the requirements of muscles in the next stage through a deep learning model on the basis of pelvic floor electromyographic signals, pressure data and infrared thermal imaging which are collected in real time, and the treatment accuracy is improved. Dynamically generating a composite pulse waveform; the multi-objective reinforcement learning parameter optimization module constructs a'state-action-reward 'reinforcement learning framework, and takes patient treatment feedback, muscle force improvement, pain score and treatment compliance as reward signals.

Traditionally, feature extraction and thickness quantification of Pulsed eddy current (PEC) composite signals from multiple concentric pipes in oil and gas wells or similar, have been approached via pre-built frequency domain inversion models that do not utilize in-situ data and are subject to many unknown variables. We apply independent component analysis (ICA) with known applications in other areas including facial feature extraction, in a novel fashion to determine from in-situ data, the original independent PEC signals corresponding to each pipe, from their composite signal, hence allowing the thickness of each pipe to be reliably quantified. Since ICA is unsupervised, no prior modelling with synthetic or out-of-sample data is required, rather in-situ data is utilized. The results are consistent across logging tool manufacturers as prior knowledge of each tool sensor / physics is not required.

The application discloses a low-vibration active phase modulation composite pulse tube Stirling cryogenic refrigerator and belongs to the technical field of cryogenic refrigerators. The composite refrigerator cold finger integrates a first Stirling component as a high-temperature stage and a second pulse tube component as a low-temperature stage. The innovation is that the phase modulation unit of the second pulse tube component is composed of a second inertia tube wound and fixed in the inner circle of the gas reservoir, and the gas reservoir is integrally connected to the first cold end heat exchanger to improve the system efficiency through low-temperature arrangement. At the same time, the motion state of the compressor piston and the first displacer is monitored and cooperatively controlled in real time through the compressor displacement sensor and the cold finger displacement sensor, active and accurate phase modulation is realized, and the active vibration damper is used to perform reverse compensation according to the motion feedback of the first displacer to significantly offset the vibration output of the whole machine. The application realizes the unity of high efficiency, low vibration and high reliability, and is particularly suitable for vibration-sensitive space exploration and other application scenarios.

The invention discloses a composite pulse jet flow exciter, a using method and an aircraft, belongs to the technical field of aircrafts, and aims to solve the technical problems of limited frequency and single mode of an existing pulse jet flow exciter in related technologies. The composite pulse jet exciter comprises a confluence channel and multiple sets of electromagnetic valves, the multiple sets of electromagnetic valves are arranged in parallel, the electromagnetic valves are communicated with an air source, the confluence channel is provided with multiple air inlet sections, the number of the air inlet sections is the same as that of the electromagnetic valves, inlets of the air inlet sections are connected with the electromagnetic valves, and the confluence channel further comprises confluence sections. Outlets of the multiple air inlet sections communicate with the confluence section, and airflow passing through the multiple sets of electromagnetic valves converges at the confluence section. The multiple sets of electromagnetic valves are arranged side by side, so that airflow controlled by the multiple sets of electromagnetic valves is compounded in the confluence channel, and the frequency limitation of a pulse jet exciter is broken through; and the excitation working mode of the pulse jet flow is widened.

This application discloses a method and related equipment for collaborative current sharing control of multiple charging modules in power transmission and distribution equipment, which can achieve efficient, reliable, and long-life operation of charging modules in power transmission and distribution equipment. This application includes: periodically collecting multi-dimensional state parameters of each charging module, including at least output current, output voltage, module temperature, and equivalent series resistance of the capacitor; calculating the dynamic output internal resistance of each charging module by inputting a multi-frequency composite pulse load to each charging module under no-load conditions; dynamically dividing each charging module into a working group and a standby group based on module temperature, equivalent series resistance of the capacitor, and dynamic output internal resistance; dynamically calculating the comprehensive performance weight of each charging module in the working group based on the multi-dimensional state parameters; and allocating a target current to each charging module according to its weight ratio based on the total system load current and the comprehensive performance weight of each charging module.

This invention relates to a high-speed signal acquisition system, specifically a single-channel wide dynamic range single fast pulse signal acquisition system, solving the technical problem of acquiring a large dynamic range of a single fast pulse P1. The single-channel wide dynamic range single fast pulse signal acquisition system provided by this invention includes a composite pulse train shaping circuit S1, a data acquisition unit S2, and an acquisition and restoration unit S3. The composite pulse train shaping circuit S1 includes a power divider circuit U1, N attenuation circuits U2, N analog delay circuits U3, and a composite circuit U4, where N is an integer greater than 1. The input terminal of the composite pulse train shaping circuit S1 receives a fast pulse P1, first splits the input fast pulse P1, then delays each of the split circuits, and finally combines them into a pulse train P2. Multiple samplings of the single fast pulse P1 signal are achieved within a short time using a single recording channel. Furthermore, by configuring different attenuation parameters for each split circuit, a large dynamic range of the single fast pulse P1 signal can be acquired.

The invention discloses a DC bus ground insulation parameter measurement method and terminal, and the method comprises the steps: injecting a composite pulse current source containing a first frequency pulse and a second frequency pulse between a DC bus and the ground, and collecting the voltage response of the DC bus corresponding to the composite pulse current source; calculating a first admittance and a second admittance corresponding to different frequencies according to the voltage response; and according to the first admittance and the second admittance, obtaining a ground Y capacitance and an insulation resistance value of the DC bus. The voltage response corresponding to the direct-current bus is obtained by injecting the composite pulse current source containing the first frequency pulse and the second frequency pulse which are different, then admittance analysis calculation is carried out according to the voltage response, the earth Y capacitance and the insulation resistance value are obtained, and the voltage response and the insulation resistance value are obtained by adopting a pulse response and admittance analysis calculation mode. And the detection time is short and is not limited by the installation position.

The application relates to the technical field of laser pulse, in particular to a composite pulse laser device which comprises an output mirror, a polarizer, a laser gain module, a first reflector, a first Q switch, a second reflector, a second Q switch and a controller, the first reflector, the first Q switch, the polarizer and the output mirror form a first pulse laser resonant arm cavity, the second reflector, the second Q switch, the polarizer and the output mirror form a second pulse laser resonant arm cavity, the polarizer transmits first direction polarized laser and reflects second direction polarized laser, tens of nanoseconds and hundreds of nanoseconds laser are output from the laser gain module and the output mirror, the output of pulse laser of the first pulse laser resonant arm cavity and the second pulse laser resonant arm cavity is controlled by the controller, the pulse interval is flexibly adjustable, the application has compact structure and flexible design, tens of nanoseconds and hundreds of nanoseconds laser output can be simultaneously realized under the control of the same electric signal, and the application has strong practicability.

A receiver convolves an impulse response for compensating for frequency characteristics and a complex impulse response for wavelength dispersion compensation with each of a real component and an imaginary component of each polarized wave of a reception signal. For each polarized wave, the receiver performs complex signal processing of multiplying the imaginary component by the imaginary unit, then branching the resulting component, and adding one imaginary component to the real component. For each polarized wave, the receiver uses, as input signals, the real component and the imaginary component of each polarized wave after complex signal processing and the phase conjugates of them. For each polarized wave, the receiver adds a signal obtained by a process in which each of the real component and the imaginary component of each polarized wave is multiplied by a complex impulse response, the resulting components are added, and a phase rotation is applied and a signal obtained by a process in which each of the phase conjugate of the real component and the phase conjugate of the imaginary component of each polarized wave is multiplied by a complex impulse response, the resulting components are added, and an opposite phase rotation is applied, and adds a transmission data bias correction signal.

This invention discloses an energy control method for high-energy electrohydraulic detonation, belonging to the field of pulse power technology. It includes: control of the electrical and chemical energy of a metal wire, utilizing the high amplitude component of a composite pulse power to rapidly deposit electrical energy into the metal wire and completely release its chemical energy; control of plasma channel deposition energy, adjusting the channel deposition energy and external radiated heat through the long pulse width component of the composite pulse power, enabling the metal powder to react with the liquid medium and release energy; control of metal powder release energy, adjusting the reaction rate between the metal powder and the liquid medium to achieve self-sustaining reaction and improve the energy release efficiency of the metal powder; and control of shock wave energy, adjusting the composite pulse power, metal wire size, and metal powder parameters to improve the conversion efficiency of the deposited energy into shock wave energy, meeting application requirements. This invention achieves precise energy control during electrohydraulic detonation through the matching of multiple stages.

The invention discloses a double-frequency phased array composite pulse histotripsy system and a double-frequency phased array composite pulse histotripsy method. Comprising a double-frequency phased array transducer, a driving control module, a focus control module and a real-time monitoring module, wherein the double-frequency phased array transducer is a double-frequency hundreds of array element phased array transducer or a double-frequency split array transducer; the double frequency multiplication phased array transducer comprises a fundamental frequency array element group and a frequency multiplication array element group, the driving control module is used for outputting driving signals with corresponding frequencies to two groups of array elements, the focus control module is used for regulating and controlling the positions and the number of focuses, and the real-time monitoring module is used for tracking the effect; the double-frequency phased array composite pulse histotripsy system adopts a four-stage composite pulse time sequence to cooperatively control the working states of a fundamental frequency array element group and a frequency multiplication array element group, and is realized in combination with a multi-focus control strategy; according to the method, the defect of fogging zone front cavitation shielding possibly caused by double-frequency millisecond long-pulse tissue damage and the defect that instant B-ultrasonic monitoring is affected by slow bubble dissipation after treatment are overcome.

A method for robust state manipulation in quantum information processing comprises evanescently coupling a first waveguide to a second waveguide, the first and second waveguide having different geometries respectively; and providing waveguide geometries such that their coupling is detuned, the detuning being a function of the geometries, the detuned coupling thereby providing reliable population transfer between the first and second waveguides that is robust to fabrication and other errors. The method may be used to provide a quantum optical coupler.

A method for robust state manipulation in quantum information processing comprises evanescently coupling a first waveguide to a second waveguide, the first and second waveguide having different geometries respectively; and providing waveguide geometries such that their coupling is detuned, the detuning being a function of the geometries, the detuned coupling thereby providing reliable population transfer between the first and second waveguides that is robust to fabrication and other errors. The method may be used to provide a quantum optical coupler.

Techniques, systems and apparatus are described for magnetic resonance imaging. A method includes applying a radio frequency (RF) signal of a predetermined time duration towards a target, wherein the RF signal comprises a composite pulse that includes a velocity-selective pulse comprising RF pulses whose phase shift is modulated over the predetermined time duration, acquiring a magnetic resonance signal from the target resulting from the application of the RF signal, and generating an MRI image of the target from the magnetic resonance signal.

The invention discloses an internal mixing online self-cleaning method based on torque prediction synergy, and relates to the technical field of rubber mixing, torque curves, acoustic emission waves and vibration signals are synchronously collected through multi-source sensing, deposition activation coefficients are calculated, and deposition risks are recognized early; low-amplitude torsional vibration desorption is adopted, and the low-amplitude torsional vibration is excited by the rotor wing end to safely and efficiently crack sediments, so that additional wear is avoided; directional jet flow is utilized, the nozzle pressure and the jet flow duration time are automatically adjusted according to the deslagging efficiency coefficient, rapid deslagging is achieved, and the cleaning efficiency is improved; receiving the deposition activation coefficient and the slag discharge amount data, correcting the torque baseline in real time and optimizing the prediction precision; and in combination with focused ultrasound and low-temperature plasma composite pulse, the residual hard shell is quickly desorbed, and a deposition activation coefficient is fed back and updated. And the running efficiency and the service life of the internal mixer can be remarkably improved, energy consumption and abrasion are reduced, and meanwhile, cleaning agent and waste liquid discharge is reduced.

The invention discloses a manufacturing method of a ceramic plate with a 3D structure. The manufacturing method comprises the following steps: a, manufacturing a ceramic substrate; b, manufacturing a metal frame; c, preparing a brazing material; d, active brazing; and e, solder resist printing, surface treatment and subsequent processes. According to the invention, composite pulse waveform and direct current combined parameters are adopted, so that an X-shaped bridging structure and efficient hole-filling electroplating of high-density and high-aspect-ratio through holes of the ceramic plate are realized; the printing thickness and uniformity are monitored in real time in the brazing filler metal coating process, and the air tightness and the tensile strength are improved; in addition, surface treatment of nickel and gold electroplating under the box dam structure is achieved in the modes that the gold / nickel layer is removed through laser to expose the copper layer, copper is selectively removed through alkaline etching, the titanium layer is etched through plasma and the like, and the ceramic plate manufactured through the mode has the advantages of being high in binding force, high in air tightness and good in reliability.

A method for robust state manipulation in quantum information processing comprises evanescently coupling a first waveguide to a second waveguide, the first and second waveguide having different geometries respectively; and providing waveguide geometries such that their coupling is detuned, the detuning being a function of the geometries, the detuned coupling thereby providing reliable population transfer between the first and second waveguides that is robust to fabrication and other errors. The method may be used to provide a quantum optical coupler.

The application provides an electrode preparation method by periodical deposition, and belongs to the technical field of electrochemical electrode preparation, which comprises the following steps: preparing a nanomaterial hyperdispersion stabilizing aid containing a non-ionic block copolymer dispersant and modified nanosilica; preparing a composite electrolyte containing a main salt, a buffer, a conductive agent, an additive, the nanomaterial hyperdispersion stabilizing aid and a composite electrolyte additive; after pretreating a substrate, placing the substrate in the composite electrolyte; adopting a nucleation deposition of a forward square wave pulse, a structure construction deposition of a variable duty cycle pulse, a functional gradient deposition of a multistage composite pulse and a surface modification deposition of a high-frequency symmetric pulse in a fourth stage; and post-treating the deposited electrode; through the synergy of the functional aid system and the multistage deposition process, the electrode prepared by the method has the comprehensive advantages of good thickness uniformity, strong bonding force, high electrochemical activity, excellent cycle reversibility and high structural stability.

The application discloses an intelligent regulation type Venturi gas-liquid composite pulse automatic fire extinguishing device and a control method, which comprises a Venturi gas-liquid mixing nozzle, a high-pressure gas storage bottle unit, an electromagnetic valve, a fire extinguishing agent storage unit, an azimuth regulation execution assembly, an intelligent monitoring and positioning module and a central control unit. The central control unit is configured to drive the azimuth regulation execution assembly to aim the outlet of the Venturi gas-liquid mixing nozzle at a fire source according to a monitoring signal of the intelligent monitoring and positioning module, and control the electromagnetic valve to be opened and closed in a short pulse mode to perform millisecond pulse spraying. The liquid in the fire extinguishing agent storage unit is automatically sucked and atomized by using the negative pressure generated by the nozzle throat during spraying to form a gas-liquid composite fire extinguishing medium. The fire extinguishing agent can be accurately guided to the root of the fire source, the generated gas-liquid composite medium has the rapid suffocation ability of gas and the high-efficiency cooling and anti-reignition ability of liquid, and the single spraying impact force is small.

The invention relates to a pulse sequence generation method and device, computer equipment, a storage medium and a product. The method comprises the following steps: acquiring intestinal function information of a target object; determining pulse frequency according to the intestinal function information; the pulse frequency comprises a reference frequency, a first frequency and a second frequency, the reference frequency is matched with the intestinal slow wave rhythm of the target object, the reference frequency is smaller than the first frequency, the first frequency is smaller than the second frequency, and the effective level of the first pulse generated based on the first frequency comprises at least two second pulses generated based on the second frequency; overlapping and fusing a reference pulse sequence corresponding to the reference frequency, a first pulse sequence corresponding to the first frequency and a second pulse sequence corresponding to the second frequency to generate a composite pulse sequence; the composite pulse sequence is used for electrically stimulating the intestinal tract. According to the method, the intestinal slow wave rhythm, the high-frequency pulse for activating the nerve plexus and the low-frequency pulse for activating the muscle fiber are comprehensively considered, and the stimulation effectiveness can be improved and prolonged.

The invention provides a method and equipment for generating a composite pulse electric field signal, and the method comprises the steps: generating a composite digital driving signal containing microsecond sequential logic and nanosecond sequential logic through a control module; and a high-speed solid-state switch matrix responds to the composite digital driving signal and inverts the direct-current high voltage into a composite pulse waveform which structurally comprises microsecond-level time sequence characteristics and nanosecond-level time sequence characteristics at the same time. The equipment comprises a control module, a high-voltage direct-current power supply module and the high-speed solid-state switch matrix adopting the wide bandgap semiconductor device. According to the method, the composite pulse waveform containing microsecond and nanosecond dual time sequence characteristics is generated, the high-frequency characteristic of the nanosecond characteristics is utilized to avoid the response frequency of neuromuscles, it is guaranteed that the microsecond characteristics provide enough ablation energy, meanwhile, muscle contraction and pain in the treatment process are fundamentally inhibited, the operation safety and economical efficiency are improved, and the treatment cost is reduced. And the ablation efficiency is expected to be improved through a dual electroporation mechanism.

The invention discloses a multi-module cooperative current sharing control method for charging in power transmission and distribution equipment and related equipment, which can realize efficient, reliable and long-life operation of charging modules of the power transmission and distribution equipment. The method comprises the following steps: periodically collecting multi-dimensional state parameters of each charging module, wherein the multi-dimensional state parameters at least comprise output current, output voltage, module temperature and capacitance equivalent series resistance; when the system is in a no-load state, the dynamic output internal resistance of each charging module is calculated by inputting a multi-frequency composite pulse load to each charging module; dynamically dividing each charging module into a working group and a standby group based on the module temperature, the capacitance equivalent series resistance and the dynamic output internal resistance; dynamically calculating the comprehensive performance weight of each charging module in the working group based on the multi-dimensional state parameters; and according to the total load current of the system and the comprehensive performance weight of each charging module, distributing a target current to each charging module according to a weight ratio.

The application discloses a kind of general three-phase / single-phase alternating current charging pile output relay sticking detection method and device, method includes the following steps: provide a kind of general three-phase / single-phase alternating current charging pile output relay sticking detection device;After receiving charging instruction, keep output relay to be disconnected state, close switch circuit, utilize output processing circuit respectively to the contact output voltage of three-way output contact rectification after superposition, obtain first composite pulse waveform;First composite pulse waveform is handled by isolation circuit to obtain second composite pulse waveform, second transmission composite pulse waveform is to MCU, and MCU judges the sticking condition of output contact according to second composite pulse waveform;Implement the application, improve the detection accuracy of charging pile output relay, not only reduce cost, but also help more accurate, safe and reliable determination contact sticking condition.

The invention provides a modularized, low-inductance and high-reliability composite pulse power supply assembly, so as to solve the problems of complex system, high cost, limited performance, switching disturbance and the like caused by discrete design of a fast pulse power supply and a quasi-steady-state power supply in an existing theta-pinch device. Through standardized and integrated mechanical and electrical design, hardware unification of two power supply topologies is realized, loop parasitic inductance is reduced, seamless transition from pulse to steady-state current is ensured, and finally the core targets of improving plasma experiment performance, simplifying system architecture and reducing full life cycle cost are achieved.

Embodiments of the present application provide a cooperative pulse generation apparatus, device and generation method. The synergistic pulse generation apparatus comprises a drive circuit and a pulse generation circuit. The drive circuit receives a first control signal and a second control signal sent by a host computer, converts the first control signal into a first drive signal, and converts the second control signal into a second drive signal. The pulse generation circuit comprises a first power supply, a second power supply, a first pulse generation module, and a second pulse generation module. The first pulse generation module stores electric energy supplied by the first power supply and discharges the electricity under the control of the first drive signal to form a first pulse signal, and the second pulse generation module stores electric energy provided by the second power supply and discharges the electricity under the control of the second drive signal to form a second pulse signal. The present embodiment can selectively form a first pulse signal and / or a second pulse signal having different widths, thereby achieving the purpose of applying a composite pulse to a load.

The invention discloses a pulse capacitor adopting a child-mother core group, and relates to the technical field of pulse power, the pulse capacitor comprises a mother core control module and at least two child core modules, each child core module comprises an energy storage capacitor unit and a switch unit connected in series with the energy storage capacitor unit; the controller of the mother core control module is connected with the control end of the switch unit of each sub-core module through a driving circuit; the mother core control module responds to the discharge command and determines a target control mode; the control mode of the mother core control module comprises: an independent gating discharge mode: selecting at least one sub-core module based on a trigger instruction, and discharging energy of the sub-core module to equipment; according to the cooperative time sequence discharge mode, multiple trigger signal sequences are generated based on an advanced waveform description instruction, the sub-core modules are conducted in sequence or in an overlapped mode according to a specific time sequence, currents of the sub-core modules are overlapped on equipment to obtain composite pulses, and the problems that the capacitor discharge mode is single, the system reliability is low, and the service life is affected by large current impact are solved.

The invention discloses a low-vibration active phase modulation composite pulse tube Stirling refrigerator, and belongs to the technical field of low-temperature refrigerators. The composite refrigerator cold finger integrates a first-stage Stirling assembly serving as a high-temperature stage and a second-stage pulse tube assembly serving as a low-temperature stage. The system is characterized in that a phase modulation unit of the second-stage pulse tube assembly is formed by winding and fixing a second-stage inertia tube on the inner circle of the gas reservoir, the whole gas reservoir is fixedly connected to the first-stage cold end heat exchanger, and the system efficiency is improved through low-temperature arrangement. Meanwhile, a compressor displacement sensor and a cold finger displacement sensor are used for monitoring in real time and cooperatively controlling the motion state of a compressor piston and a first-stage discharger, and active and accurate phase modulation is achieved; and reverse compensation is carried out according to the motion feedback of the first-stage discharger by utilizing the active shock absorber, so that the vibration output of the whole machine is remarkably counteracted. The method realizes the unification of high efficiency, low vibration and high reliability, and is particularly suitable for application scenes such as space detection sensitive to vibration.

The application discloses a quantum frequency calibration method and system based on a composite pulse sequence. The method comprises the following steps: continuously applying a composite pulse sequence to a quantum bit for several times; measuring the quantum bit after the composite pulse sequence is applied based on a reading pulse to obtain a quantum bit excited state population curve; and performing function fitting on the quantum bit excited state population curve to obtain a fitting function and a quantum bit frequency offset. The system comprises a composite pulse sequence module, a quantum bit measurement module and a function fitting module. By using the application, the coherence time of the quantum bit can be prolonged, and the quantum bit frequency offset can be accurately calibrated. The application can be widely applied to the technical field of quantum measurement and control.

This invention relates to an ultrafast laser processing system and method for thin-film temperature sensors. A beam splitting module divides the beam output from a single femtosecond laser into two paths, which are then shaped into a femtosecond pulse train and a picosecond pulse by a femtosecond pulse generation module and a picosecond pulse generation module, respectively, achieving single-source dual-pulse-width beam output. A composite module adjusts the delay and synthesizes the two pulses, ensuring precise temporal coordination between the picosecond pulse and the subsequent femtosecond pulse train: the picosecond pulse, with its pulse width shorter than the thermal diffusion time, rapidly preheats the metal substrate; the femtosecond pulse train, with its ultrafast characteristics, precisely controls the temperature field of the preheated region. Through the shaped composite pulse train, the timescale of metal oxidation / nitriding reactions forming ceramic thin films can be precisely matched, enabling active control of the thermal diffusion and thermal equilibrium processes, thereby obtaining a ceramic thin-film sensitive unit layer with controllable local thickness, crystal form, and composition.

The invention discloses a multi-parameter adjustable pulse signal generation method for adaptive environment perception, and belongs to the field of pulse signal generation and control. The method comprises the following steps: generating a pulse signal based on an initial pulse signal parameter and transmitting the pulse signal; receiving and collecting echo signals and environmental parameters of a target medium in real time, and performing feature extraction processing on the currently collected echo signals and environmental parameters to obtain signal features and environmental features; dynamically generating an optimal pulse signal parameter of the current round based on the signal characteristics and the environment characteristics so as to generate a composite pulse signal and transmit the composite pulse signal to the detection area; in the continuous pulse emission and echo feedback process, pulse signal parameters are subjected to iterative adjustment, the optimal pulse signal parameters of the current round are locked when the number of times of convergence is carried out, a working mode is entered, and meanwhile monitoring and adjustment are continuously carried out. Under the condition of a complex inhomogeneous medium or a dynamic non-matched load, the penetration depth, the resolution and the signal-to-noise ratio of a pulse signal are improved, and energy efficiency and self-adaptive performance are considered at the same time.