52 results about "Long pulse" patented technology

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 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.

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.

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 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.

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.

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.

The application provides a kind of adaptive analog control circuit for high-speed serdes equalization system, comprising error amplifier circuit, sampling signal generation circuit, sample-and-hold circuit;Sampling signal generation circuit, through negative feedback network, circuit sampling signal only appears when the input signal pulse width of high-speed serdes equalization circuit is the longest, so that the adaptive analog control circuit only collects the rising and falling edge information on the signal with the longest pulse width to realize adaptive control function, reduces the response speed requirement of the equalization system to operational amplifier, improves the highest speed that the circuit can support, and at the same time can reduce the power consumption of the circuit.

The invention provides a gyrotron rapid voltage regulation method based on long pulse power forbidden zone prejudgment, and belongs to the field of nuclear fusion plasma heating, and the method comprises the steps: setting target power, and determining the adjustment amplitude of the gyrotron anode voltage based on the target power; starting the gyrotron until the power of the gyrotron reaches a safety advance point which is located before the starting boundary of the power forbidden zone, and adjusting the anode voltage of the gyrotron to the target voltage at one time according to the adjustment amplitude; under the target voltage, the power of the gyrotron rapidly passes through a power forbidden zone and then climbs to the target power, and enters long-pulse steady-state operation; the invention further provides a system. A power forbidden zone and a safety advance point of long pulse operation are identified through statistical analysis, and the anode voltage is pre-judged and adjusted at one time when the safety advance point is reached in the starting process, so that the gyrotron quickly adjusts the voltage of the power forbidden zone after boosting, and directly reaches a target power stable zone; therefore, the long-pulse starting success rate is obviously improved, the fault risk is reduced, and the starting time is shortened.

This invention relates to a short-pulse loop induced voltage superimposed device and its assembly method; it solves the problems of long pulse loops and large inductance in existing induced voltage superimposed devices; it includes an induced voltage superimposed device body, which comprises a secondary magnetically insulated transmission line, a first-stage induction cavity, a secondary supporting vacuum cavity, and a ring-shaped short-circuit connecting piece; the secondary magnetically insulated transmission line includes a pulse superimposed section and a cantilever supporting section inner cylinder connected together, the first-stage induction cavity being sleeved outside the pulse superimposed section; the secondary supporting vacuum cavity being sleeved outside the cantilever supporting section inner cylinder, with one side connected to the cantilever supporting section inner cylinder and the other side connected to the first-stage induction cavity; the short-circuit connecting piece is made of conductive material; the short-circuit connecting piece is sleeved outside the pulse superimposed section, located within the gap, and its inner and outer sides are respectively attached to the outer wall of the pulse superimposed section and the inner wall of the first-stage induction cavity; this invention also proposes an assembly method for the above device.

The application of the invention is a divisional application of Chinese application 202210187020.9. The invention provides a programming method of a memory, the memory and a memory system, and relates to the technical field of storage. The method comprises the steps of applying a first programming voltage to a selected word line with a first pulse width in a first pulse stage of programming a selected memory unit; and in a second pulse stage for programming the selected memory unit, applying a second programming voltage to the selected word line with a second pulse width. Different pulse bandwidths are adopted in different pulse stages in the programming process, the corresponding pulse bandwidths are adopted for programming according to programming voltages of the pulse stages, and when the programming voltages are low, the long pulse bandwidths can be adopted, and enough programming duration is guaranteed; and when the programming voltage is relatively high, a relatively short pulse bandwidth is adopted, so that the supplementary potential is improved, and the loss caused by programming voltage interference is reduced.

The application discloses a material strain rate tensile test system and relates to the technical field of dynamic mechanical property test of materials. The material strain rate tensile test system comprises a motor-based power system and a control system, a waveform separation long pulse width stress wave test system based on multipoint strain measurement and a strain test system based on a high-speed camera and DIC technology. The material strain rate tensile test system accelerates a large mass block to a predetermined speed through a motor, impacts an anvil head connected with a sample to perform tensile loading on the sample, measures stress borne by the sample through a Hopkinson bar and a multipoint waveform separation technology, measures sample deformation through digital image processing technology DIC, and thus obtains a stress-strain curve of the sample. The data waveform obtained by the application is smooth, reliable, simple to operate, low in cost, and capable of realizing a strain rate of 10 1 ~ 10 2 s ‑1 , and fills the strain rate test blind area between a material servo testing machine MTS and a traditional Hopkinson bar.

SOLUTION: Free-space optical (FSO) wireless transmission, including optical communications, remote-sensing, power beaming, etc., can be enhanced by replacing conventional laser sources that operate in the infrared portion of the optical spectrum with ultra-short pulsed laser (USPL) sources 102 having peak pulse powers of 1 kW or more and pulse lengths of less than 1 picosecond. Specifically, it has been observed that, under these conditions, the attenuation of an USPL beam having the same average optical power as a conventional laser in a lossy medium, such as the atmosphere, is substantially less than the attenuation of a conventional laser beam having a lower peak pulse power and / or a longer pulse width.EFFECT: The superior system performance in using a USPL can be translated into an increased distance between a laser source in a transmitter and a photodetector in a receiver and / or higher reliability of the system in inclement weather conditions.SELECTED DRAWING: Figure 1

The present invention provides a ZeroMQ-based long-pulse data publishing method and system, belonging to the technical field of magnetic confinement nuclear fusion devices. The method comprises the following steps: before a plasma discharge experiment, if data acquisition configuration needs to be updated, an acquisition console sends configuration information to an acquisition unit; at the start of the experiment, the acquisition console sends shot number information to the acquisition unit and a data server. The acquisition unit continuously acquires experimental data and simultaneously sends the experimental data to the data server. During this period, the acquisition unit continuously publishes status information, allowing the acquisition console to monitor the status of the acquisition unit. The data server stores the experimental data and publishes it to users. In the present invention, based on different data types such as configuration information, shot number information, status information, and experimental data, combined with multiple ZeroMQ data communication modes, reliable data transmission is achieved, effectively helping experimenters view experimental data in near real time during long-pulse plasma discharge experiments.

The embodiment of the invention provides a modulation method and device for a three-level inverter and the three-level inverter, and the method comprises the steps: obtaining a target voltage vector which needs to be outputted by the three-level inverter in a modulation period; acquiring a narrow pulse suppression threshold value; judging whether the effective level pulse width corresponding to the target voltage vector is smaller than a narrow pulse suppression threshold value or not; when the pulse width of the effective level is smaller than a narrow pulse suppression threshold value, at least one switch assembly in a modulation period is conducted, and the originally dispersed short-pulse-width effective level is integrated into a continuous long-pulse-width effective level; wherein the duration of the long pulse width effective level is greater than the narrow pulse suppression threshold. According to the scheme, output voltage distortion caused by pulse suppression and dead zone effect superposition is eliminated, and the output waveform quality is remarkably improved.

The present technology is directed generally to electrical stimulation and associated systems and methods. For example, in some embodiments a first electrical signal can be applied to a target neural population via two or more electrodes on a signal delivery element, and a second electrical signal can be applied to two or more different electrodes on the signal delivery element. The first electrical signal and the second electrical signal can have different parameters. For example, the first electrical signal can have a frequency under 1.2 kHz and the second electrical signal can have a frequency greater than 1.2 kHz. In some embodiments, the first electrical signal has a relatively long pulse width, such as between about 5 milliseconds and about 2 seconds, such that it approximates a direct current signal.