64 results about "Long pulse" patented technology

The invention discloses an ultrafast laser partition impact strengthening method and device for a thin-wall covered edge of a composite blade. According to the method, the surface of the thin-wall covered edge is strengthened by utilizing the characteristics of instantaneous high pressure of shock waves induced by ultrafast laser and accurate and controllable propagation depth, and meanwhile, according to the thickness characteristics of different areas of the covered edge, laser with different pulse widths is selected to carry out partitioned strengthening treatment, so that accurate regulation and control of a surface residual stress field are realized on the premise of inhibiting deformation; the problem of cooperative control of surface strengthening deformation and a stress field of the thin-wall edge covering structure is solved. According to the thickness characteristics of different areas of the edge covering structure, based on the principle that the shorter the laser pulse width is, the shallower the shock wave propagation depth is, the shallow the depth of a residual stress field influence layer is and the edge covering structure is not prone to deformation, a femtosecond / picosecond pulse width laser combined shock peening method is provided, and femtosecond laser shock is adopted in a thin-wall area; femtosecond laser or picosecond laser with relatively long pulse width is adopted for impact in a wall thickness area, and precise regulation and control of a surface stress field are achieved on the premise of restraining thin-wall wrapping edge deformation.

According to certain embodiments, a method by a network node for linear chirp detection includes obtaining a first number, N, of samples of a signal. The samples are divided into at least a first group and a second group, where the first group includes a second number, D, of the samples of the signal and the second group includes a third number, N−D, of the samples of the signal. A correlation is performed between the first group of samples and the second group of samples to generate a resultant group of samples of the signal. Within the resultant group of samples, a peak value is identified in the frequency domain Based on at least one property associated with the peak value, it is determined whether there is a linear chirp within the signal.

The invention belongs to the technical field of geophysical exploration, and relates to an underground water magnetic resonance longitudinal relaxation time detection method, which comprises the following steps: laying a magnetic resonance detection coil on the ground, fixing a short emission time, changing a current amplitude, emitting a plurality of short pulses, and collecting a short pulse observation signal generated by each short pulse; fixing a long emission time, re-emitting a series of long pulses with different current amplitudes, and collecting a long pulse observation signal generated by each long pulse; inverting the short pulse observation signal to obtain water content and transverse relaxation time distribution of underground water at different depths; and taking the water content and the transverse relaxation time distribution of the underground water at different depths as prior data of Bayesian inversion, and analyzing the long pulse observation signal by adopting Bayesian inversion to obtain longitudinal relaxation time distribution. According to the invention, a complex excitation sequence form is not needed, and a longitudinal relaxation signal of a short relaxation sample with a fast attenuation speed can be captured. The method is suitable for a high-power scene of field ground magnetic resonance detection.

The invention discloses a semiconductor laser pulse driving circuit based on a super capacitor, and belongs to the technical field of electronic circuits. The circuit comprises at least one super capacitor which supplies power to the vertical cavity surface emitting laser; the current control and sampling circuit is used for controlling the current circulation and closing of the vertical cavity surface emitting laser and sampling and monitoring the discharge current of the super capacitor through the current control and sampling circuit, and the current control and sampling circuit is connected with the vertical cavity surface emitting laser and the super capacitor in series to form a laser discharge loop; and the charging circuit is used for dynamically adjusting the voltage output by the charging circuit according to the sampling result of the current sampling point so as to adjust the voltage value of the super capacitor. The super capacitor is used for supplying power to the vertical cavity surface emitting laser, millisecond-level long-pulse and large-current driving current output can be achieved, meanwhile, the average power requirement of a circuit front-end power source is lowered by means of duty ratio limitation of practical application, and then cost is lowered.

The invention provides a water beam guided laser processing technology and method for optimizing a deslagging channel, and the method for processing a workpiece through water beam guided laser comprises the following steps: on the basis of a front optimization design downward deslagging channel or a preferable processing direction, utilizing the efficient characteristics of preferable continuous wave (CW-M) laser, quasi-continuous wave (QCW) laser or other laser with relatively long pulse width, the method for improving the water beam guided laser processing efficiency is achieved. In the water beam guided laser machining process, based on optimized design of a deslagging channel and optimization of lasers with long pulse width parameters, the constraint that the upward discharging efficiency of residues is very limited in the traditional water beam guided laser machining process is broken through, the machining efficiency is greatly improved, and high-efficiency, low-heat-damage, high-precision and thick plate machining is achieved.

The invention discloses a nondestructive testing method for defects of a friction part based on pulse infrared thermal imaging. The method comprises the following steps: determining thermal physical parameters of each component material of the friction part with the defects through experimental measurement or material manual query; constructing a short-pulse infrared thermal imaging detection system and a long-pulse infrared thermal imaging detection system; a short pulse infrared thermal imaging detection system and a long pulse infrared thermal imaging detection system are respectively adopted to detect the friction part, and sequence infrared images and corresponding temperature data are synchronously obtained; in the collected sequence infrared images, selecting central areas and defect-free areas of different depth defects on the friction part as feature points, and extracting temperature data of each feature point to draw a temperature-time curve; performing data reconstruction and image enhancement processing on the acquired sequence image data; analyzing the image to obtain a detection result. According to the invention, accurate detection of different depth defects in the friction part is realized, the identification capability of the depth defects is improved, the cost is reduced, and the adaptability is high.

The application discloses an active direct wave suppression method, device, computer and storage medium, which filters a received signal by using a time domain blocking matrix, suppresses an interference frequency component, and forms a new sampling sequence; and performs a discrete Fourier transform on the new sampling sequence generated after filtering to obtain a power spectrum signal after interference suppression. According to the active direct wave suppression method, device, computer and storage medium, the uniformity of a single-frequency signal in time domain sampling is utilized, alignment on a time domain waveform is realized through phase compensation, and a difference cancellation process is performed on a reference signal and an original signal, so that the frequency component is cancelled, and static reverberation is suppressed. The method is convenient to calculate, has good single-frequency direct wave interference and reverberation suppression capability, and can be used for active target detection in a single-frequency long pulse signal transmission mode, and the effective distance is improved.

The invention discloses a power battery GFRP composite material defect super-resolution detection method based on lightweight YOLOv8 and SRResNet, and the method comprises the steps: building an experimental environment through employing a super-resolution reconstruction deep learning algorithm SRResNet based on a deep residual network, training a model, carrying out the super-resolution reconstruction of an original image, and finally, carrying out the super-resolution detection of a GFRP composite material defect. A data set of network reconstruction is input into a YOLOv8-GFRP model to be recognized, the accuracy rate change achieved by the reconstructed data set is explored, a most suitable reconstruction method is found, in the process, three evaluation indexes of PSNR, SSIM and operation time are adopted to evaluate the super-resolution reconstruction effect of an image, and the super-resolution reconstruction effect of the image is evaluated. Therefore, the advantages of the SRResNet-based network in GFRP layering defect detection by using the long-pulse thermal imaging technology are verified. The method has the advantages of high accuracy, high efficiency, high automation and the like, and has great advantages in the aspect of detecting GFRP defects, so that the method has important significance in the field of detection of power batteries adopting GFRP as a protection structure.

The invention discloses a long pulse debugging method for a large-area thermionic cathode ion source, and belongs to the technical field of thermionic cathode ion sources, and the method comprises the steps: carrying out the air inlet vacuum debugging after the ion source is assembled; the insulation and voltage endurance capability is improved through cold high-voltage exercise; turning off high voltage, lighting a lamp filament, applying arc voltage, and cleaning the cavity through arc chamber plasma discharge; the extraction voltage is gradually applied to perform beam extraction exercise, and beam transmission is optimized through diversion coefficient scanning; and finally, the diversion coefficient is reduced, the pulse width is prolonged, and long-pulse discharge debugging is realized. According to the method, a systematic debugging process from vacuum verification, insulation and voltage resistance, cavity cleaning to beam extraction and long pulse discharge is established, the stability and reliability of the ion source can be effectively improved, the breakdown risk is reduced, and a technical basis is provided for long-term stable operation of a large-area hot cathode ion source in the future.

The application relates to the technical field of radar signal processing, and discloses a time-frequency domain combined pulse compression processing method for long-pulse high-resolution wind measurement, which comprises the following steps: long-pulse echo data is acquired and subjected to local time-frequency block processing; a theoretical track of a candidate distance unit in a time-frequency plane is constructed according to a propagation time delay; track time-frequency coefficients are extracted, and a frequency domain consistency factor, a local time-frequency energy focusing factor and a Doppler consistency factor are calculated; combined compression weights are generated; the amplitude of a time domain matched filter output is adjusted and the phase information is kept; combined pulse compression output is obtained; and Doppler spectrum estimation is carried out to obtain radial wind speed information. According to the application, the long-pulse echo data is subjected to local time-frequency block processing, and a theoretical track is constructed, so that the frequency domain consistency factor and the local time-frequency energy focusing factor are calculated, thereby reducing distance sidelobe leakage and improving distance resolution capability.

A magnetic array includes a plurality of magnetoresistance effect elements and a pulse application device configured to apply a pulse to at least one of the plurality of magnetoresistance effect elements. Each of the plurality of magnetoresistance effect elements includes a magnetic domain wall movement layer, a ferromagnetic layer, and a nonmagnetic layer interposed between the magnetic domain wall movement layer and the ferromagnetic layer. The pulse application device outputs a first pulse and a second pulse at different times. Voltages of both the first pulse and the second pulse are voltages at which a current density equal to or higher than a threshold current density required for moving a magnetic domain wall of the magnetic domain wall movement layer is acquired. The second pulse has a higher voltage than the first pulse or a longer pulse length than the first pulse. The pulse application device outputs the second pulse whenever the first pulse is output at a prescribed frequency or with a prescribed probability.

The invention provides an optical fiber laser module and a Raman optical fiber laser. The optical fiber laser module comprises a seed light source, a first light modulation unit, a pre-amplification unit, a second light modulation unit and a main amplification unit which are sequentially and optically connected. The seed light source is used for emitting continuous seed light, the first light modulation unit is used for modulating the continuous seed light into first pulse light with repetition frequency and narrow bottom width, and the pre-amplification unit is used for pre-amplifying the first pulse light and outputting pre-amplified signal light. The second light modulation unit is used for modulating the pre-amplified signal light into second pulse light with the same waveform as the first pulse light; and the main amplification unit is used for carrying out main amplification on the second pulse light and outputting long pulse square wave signal light with high peak power. According to the invention, the peak power of the output laser reaches a threshold value required by Raman scattering excitation of the Raman fiber laser, key parameters such as repetition frequency and bottom width of the pulse can be accurately controlled, and finally, a high-performance pump light source with strong adaptability is provided for the Raman fiber laser.

A multi-channel laser high-precision synchronous measurement device includes a transparent scattering sphere, an optical path length adjustment system, a fused silica aspheric lens, a fast photomultiplier tube, an optical fiber, a photodiode, a digital oscilloscope, a single-shot spectrometer, and a computer. This system enables synchronous measurement of multiple ultra-wideband short pulses or multiple narrowband long pulses. The device effectively suppresses the effects of repeatedly moving optical components and mechanical repositioning sampling points for different pulses, effectively improving measurement accuracy, saving time, and increasing measurement efficiency.

This invention discloses a device and method for real-time thermal focal length measurement of a long-pulse LDA side-pump module. The device includes a detector source, a beam expander system, an LDA side-pump module, a knife edge, an energy meter, and a signal generator. The detector source serves as the detection light source for thermal focal length measurement; the beam expander system serves as a beam expander for the detector source size; the LDA side-pump module serves as a heat source generator to achieve high peak power pump injection under long-pulse pumping; the knife edge is placed on both sides of the beam waist position after the detector source passes through the LDA side-pump module to cut the transverse and longitudinal beams, achieving beam size characterization; the energy meter is placed in the rear region of the measurement device to acquire the energy measurement of the detector source; and the signal generator serves as a timing control part to achieve timing synchronization between the detector source and the LDA side-pump module. This invention uses timing synchronization combined with Gaussian beam transmission transformation to obtain the thermal focal length value of the long-pulse LDA side-pump, which has the advantages of simple structure, ease of operation, and high measurement accuracy.

The present invention belongs to the field of geophysical exploration technology and is a method for detecting the longitudinal relaxation time of groundwater using magnetic resonance. The method comprises: laying a magnetic resonance detection coil on the ground, fixing a short emission time, varying the current amplitude to emit multiple short pulses, and collecting the short pulse observation signal generated by each short pulse; fixing a long emission time, re-emitting a series of long pulses with different current amplitudes, and collecting the long pulse observation signal generated by each long pulse; inverting the short pulse observation signal to obtain the water content and transverse relaxation time distribution of groundwater at different depths; using the water content and transverse relaxation time distribution of groundwater at different depths as prior data for Bayesian inversion, and employing Bayesian inversion to analyze the long pulse observation signal to obtain the longitudinal relaxation time distribution. The present invention can capture the longitudinal relaxation signal of samples with fast decay rates and short relaxation without the need for complex excitation sequences. The method is suitable for high-power scenarios in field ground magnetic resonance detection.

The invention relates to the technical field of electron emission, and discloses a large-current pulse micro-channel plate electron emission source and an X-ray generation device. According to the electron emission source, an electron emission function layer at the head end of an MCP assembly is excited by adopting a rapidly regulated and controlled UV LED light source, and ultrafast time sequence modulation of electron beams is realized through an avalanche multiplication process of the electron beams in the MCP. By adopting a specific high-lead, low-alkali or alkali-free glass component or ceramic substrate composite functional film layer structure, the MCP assembly has long service life stability of low resistance, high current output and high power density operation. Independent bias voltage and gating voltage synchronous with electronic pulse are applied to the MCP assembly through the driving control unit, accurate thermal management is carried out in combination with a pulse-charging circulation mode, and the problems of charge compensation and thermal limitation under large current output are effectively solved. The electron emission source breaks through the bottleneck, supports peak current density exceeding 100 mA / cm under submicrosecond pulse, and realizes hundred microampere level steady-state current output under millisecond level long pulse.

1. The name of the design product: laser instrument (long pulse handle best-selling two NJBF-OTR-HP-02). 2. The use of the design product: for cosmetic laser instrument. 3. The design points of the design product: in shape. 4. The picture or photo that best indicates the design points: perspective drawing.

A method and device for testing solar cells and components based on short pulse width, belonging to the field of solar cell testing, characterized in that: Voc, Isc, and Pmax are obtained through the first IV curve test within a flash cycle, and the accurate Pmax value is further obtained through the second test after adjusting the test parameters. By presetting the equivalent magnification of the second sampling delay, it is ensured that the test data collection in the Pmax core area in the second test is in a stable period. After setting, the test process does not require manual intervention, and accurate test results can be obtained by clicking once; the test method of the present invention does not rely on long pulse width to eliminate the capacitance effect during the test process, and can achieve the purpose of accurate testing within a relatively short pulse width, with simple effects and suitable for popularization and application.

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.

The application provides a gyrotron fast voltage regulating method based on long pulse power forbidden zone prediction, belongs to the field of nuclear fusion plasma heating, and comprises the following steps: setting a target power, determining the adjustment range of the anode voltage of the gyrotron based on the target power; starting the gyrotron until the power of the gyrotron reaches a safe advance point, the safe advance point is located before the starting boundary of the power forbidden zone, and the anode voltage of the gyrotron is adjusted to the target voltage at one time according to the adjustment range; under the target voltage, the power of the gyrotron rapidly climbs to the target power after crossing the power forbidden zone and enters long pulse steady-state operation; and the system is also provided; the power forbidden zone and the safe advance point of long pulse operation are identified through statistical analysis, the anode voltage is adjusted at one time predictively when the starting process reaches the safe advance point, the power forbidden zone is quickly regulated after the voltage of the gyrotron is raised, and the gyrotron directly reaches the target power stable region, so that the long pulse starting success rate is significantly improved, the failure risk is reduced, and the starting time is shortened.

The invention relates to the technical field of laser, and provides a quick-start random jitter delay emission laser device and an output method, and relates to the technical field of laser, the quick-start random jitter delay emission laser device comprises a piezoelectric ceramic total reflective mirror, a laser crystal, a total reflective mirror, an LD array side pumping source, a rectangular prism, an acousto-optic modulator, a driving signal generator, a random jitter delay controller and an output mirror; the piezoelectric ceramic total reflective mirror, the total reflective mirror and the rectangular prism form a long pulse waiting L-shaped resonant cavity. According to the quick-start random jitter delayed emission laser device provided by the invention, on one hand, the acousto-optic modulator is arranged to realize cavity emptying, and the laser emission time is shortened to realize quick start; and on the other hand, the laser emission time is changed by changing the time sequence random number so as to realize delay jitter, and the anti-interference performance of the multi-path laser radar is realized by presetting n groups of time sequence random numbers in advance, changing the preset time sequence random numbers and outputting different pulse lasers.

The application relates to a high-voltage pulse electric field ablation device and method, and belongs to the technical field of medical instruments, which solves the problem of long pulse edge and pulse width generated by an existing high-voltage fast switch. The device comprises a high-voltage output module, a capacitor and a control unit. The high-voltage output module comprises a first branch, an additional branch and a second branch which are connected in parallel between a direct-current high-voltage power supply and a grounding end in sequence. The first branch comprises first and second power switches which are connected in series. The second branch comprises fifth and sixth power switches which are connected in series. The additional branch comprises third and fourth power switches which are connected in series. The capacitor is connected between a first node between the first and second power switches and a second node between the third and fourth power switches. The first to sixth power switches are opened and closed to generate a bipolar high-voltage pulse with picosecond or nanosecond rising and falling edges and nanosecond pulse width. The amplitude, rising time, falling time, frequency, pulse width, positive and negative pulse time difference and pulse number of the pulse can be adjusted. The device realizes super-fast pulse rising and falling edges and super-short pulse width.

An object detection device has a transmitter that transmits a long pulse signal, in which a pulse width is longer than a predetermined time, as a transmission wave, the transmission wave being an ultrasonic wave; a receiver that obtains a received signal corresponding to a reflected wave reflected by an object of the transmission wave; a signal processor that obtains a fluctuation signal based on the received signal and detects the object based on the fluctuation signal, wherein the fluctuation signal is a signal corresponding to a composite wave generated when receiving the reflected wave and a wave which frequency is different from the reflected wave, or a signal generated by a phase change of the reflected wave when the distance to the object changes.

An extended optical pulse stretcher is provided that combines confocal pulse stretchers in combination to produce, for example, 4 reflections, 4 reflections, 12 reflections, and 12 reflections per optical circuit configuration. The inclusion of the combination of different mirror separations and delay path lengths can result in very long pulse stretching, long optical delays, and minimal efficiency losses. Also, in the extended optical pulse stretcher, at least a beam splitter can be positioned relative to the center of curvature of the mirrors to “flatten” each of the circuits to enable the beam to propagate in the same plane (e.g., parallel to the floor). Also, the curvatures and sizes of the individual mirrors can be designed to position the beam splitter closer to one of the banks of mirrors to allow the optical pulse stretchers to properly fit in an allocated location in a laser system.

The invention relates to the field of optical cable positioning and monitoring, in particular to an optical cable fault point positioning method and system for an optical cable routing survey instrument, and the method comprises the steps: carrying out the detection from the two ends of an optical cable through short pulse width, obtaining reflection curves S1 and S2, carrying out the detection through long pulse width, and obtaining a reflection curve S3; obtaining noise distribution of the S2 according to the head end curve segment of the S1 and the tail end curve segment of the S2; acquiring a signal malformation feature of the tail end curve segment of S2 relative to the head end curve segment of S1; reducing noise distribution and signal malformation features in the middle curve segment in S2 to obtain a repaired middle curve segment, and enabling the distribution of key curve points of the repaired middle curve segment to accord with the distribution of the key curve points of the middle curve segment in S3; and carrying out fault point positioning by utilizing the head end curve section of the S1, the head end curve section of the S2 and the repaired middle curve section of the S2. According to the invention, the accuracy of fault point positioning is further improved.

The invention relates to signal processing, in particular to a radar signal processing method, which comprises the following steps that: a radar generates time sequences with different pulse widths according to the detection distance; for the short pulse time sequence, the radar adaptively adopts time domain pulse compression for processing to obtain pulse compression data of the short pulse; for a long pulse time sequence, the radar adaptively adopts frequency domain pulse compression for processing to obtain pulse compression data of a long pulse; splicing the pulse compression data of the short pulse and the pulse compression data of the long pulse together to obtain a group of combined pulse compression data aiming at the distance of the detection distance; according to the technical scheme provided by the invention, the defect that radar signals are difficult to process efficiently in the prior art can be effectively overcome.

Driver device (3a-3f) for driving a semiconductor element (2a-2f), comprising: an identification signal generating circuit (11) that generates an identification signal depending on a type of an input error signal; a protective operation signal generation circuit (14) that generates a protective operation signal having a pulse width equal to that of one of the error signal and the identification signal having a longer pulse width; an identification signal terminal (FO) that inputs and outputs the identification signal; a protection operation signal terminal (FO_T) that inputs and outputs the protection operation signal; and a protection circuit (18) which performs a fault protection operation depending on a self-phase protection operation signal generated by the protection operation signal generation circuit (14) and an extraneous phase protection operation signal inputted through the protection operation signal terminal (FO_T).

The application discloses a kind of based on pulse infrared thermography's nondestructive testing method of friction component defect, the method steps are as follows: the thermal physical parameters of each component material of the friction component with defect are determined by experimental measurement or material manual inquiry;Short pulse infrared thermography detection system and long pulse infrared thermography detection system are constructed;Friction component is detected using short pulse and long pulse infrared thermography detection system respectively, and sequence infrared image and corresponding temperature data are acquired synchronously;In the sequence infrared image collected, the center area of different depth defects on friction component and defect-free area are selected as feature points, and the temperature data of each feature point are extracted to draw temperature-time curve;The collected sequence image data are subjected to data reconstruction and image enhancement processing;Analysis image obtains detection result.The application realizes the accurate detection of different depth defects inside friction component, improves the recognition ability of depth defect, reduces cost and has strong adaptability.

This invention provides a fiber optic sensing system and method based on digital dechirping. A coupler splits a narrow-linewidth laser into two paths, which are transmitted to a sweep frequency modulation module and an optical mixer, respectively. The sweep frequency modulation module modulates the narrow-linewidth laser into sweep frequency long pulses, which are then transmitted to the sensing fiber. The sensing fiber returns scattered light to the optical mixer. The optical mixer coherently mixes the narrow-linewidth laser and the scattered light to generate four mixed-frequency beams. A data acquisition and processing module acquires the first and second coherent signals obtained after detecting the mixed-frequency beams by first and second balanced detectors to obtain complex scattered signals. The complex scattered signals are dechirped to obtain dechirped scattered signals. The dechirped scattered signals are converted into frequency-domain scattered signals and demodulated to obtain the perturbation magnitude at various locations on the sensing fiber. This invention has the advantages of high spatial resolution, low sampling frequency, and demodulation unaffected by fading, while also enabling long-distance sensing.

The invention relates to the technical field of radar signal processing, and provides a pulse compression blind area recovery method based on long and short pulse fusion, which comprises the following steps: transmitting a long pulse and a short pulse in a time division multiplexing mode, and obtaining echo signals of the long pulse and the short pulse; performing digital conversion on the echo signals of the long pulse and the short pulse to obtain long pulse baseband signal data and short pulse baseband signal data; substituting the long pulse baseband signal data and the short pulse baseband signal data into a dual-channel parallel signal processing module to obtain a processed long pulse signal and a processed short pulse signal; and selectively replacing data of the processed long pulse signal based on the processed short pulse signal to obtain long and short pulse fusion data. Through system-level waveform design, information fusion and a fusion strategy of long and short pulse signals, the whole-course consistent high-precision distance measurement capability from near to far is ensured, and the capability of distinguishing and detecting a multi-target scene and a strong and weak target coexistence scene in a blind area is greatly improved.