94 results about "Energy particle" patented technology

The invention relates to the technical field of isotope production, in particular to a welding-free target capsule for isotope production and a manufacturing method of the welding-free target capsule. The welding-free target capsule comprises a target material used for generating isotopes under bombardment of high-energy particles; the first metal film covers one side of the target material; the second metal film covers the other side of the target material; wherein the first metal film and the second metal film are made of materials with ductility; the edge of the first metal film and the edge of the second metal film are attached to each other on the peripheral side of the target material and are folded into an annular sealing structure. In the invention, the metal film with good ductility is used as a coating material of the target material, and the sealing structure is formed by folding the connecting part of the metal film, so that the target capsule can be ensured to efficiently dissipate heat in a water-cooling environment, the manufacturing mode of the sealing structure can be improved, the manufacturing steps of the sealing structure are simple and easy to implement, and the manufacturing cost of the target capsule is further reduced.

The invention provides a neutral atom beam generation device and a neutral atom detector calibration device. The neutral atom beam generation device comprises an ion beam generation device used for emitting a mixed beam; the particle energy testing device comprises an incident end, a first emergent end, a second emergent end and an acquisition device, the incident end is used for receiving the mixed beam; the incident end is communicated with the second emergent end through an arc-shaped channel, and a deflection magnetic field is arranged at the arc-shaped channel, so that positive ions in the mixed beam flow deflect and bombard the acquisition device; the acquisition device is used for acquiring a first bombardment position of positive ions; the first emergent end is used for emitting a first ion beam; the processing device is connected with the collecting device and used for determining the deflection radius of the positive ions according to the first bombardment position and determining the energy of the positive ions and the neutral atoms according to the deflection radius; and the particle screening device is used for absorbing positive ions and negative ions in the first ion beam so as to emit a neutral atom beam.

The invention discloses a lunar dust protection system for a low-energy particle detector. The lunar dust protection system comprises a protective cover, a nitrogen blowing opening, a pressing device, an unfolding device, a power supply subsystem and a control subsystem, wherein the protective cover and the nitrogen blowing opening are integrally designed; the protective cover covers the head of the sensor and is consistent with the head of the sensor in shape; the nitrogen blowing port blows nitrogen into the sensor in a ground test stage to prevent pollution; the blocking cap is used for blocking before the satellite is launched to prevent dust pollution; when the system is in a protection state, the pressing device presses the protective cover and the head of the sensor, and the protective cover is released through thermal cutting according to an instruction of the control subsystem; the unfolding device is matched with the pressing device to achieve unfolding of the protective cover, and the protective cover is locked after being released to a designated position. The power supply subsystem supplies power to the pressing device according to an instruction of the control subsystem; the control subsystem periodically collects state monitoring parameters and transmits the state monitoring parameters to the load management unit, controls power-on and power-off of the pressing device according to a ground remote control instruction, and executes unfolding operation of the system.

The invention discloses a tritiated water measurement method, device, equipment, medium and product, and relates to the field of radiation detection, the method comprises the following steps: obtaining an actual nuclear pulse signal detected by a double-layer scintillator detector, and carrying out classification by using a trained convolutional neural network according to the actual nuclear pulse signal to obtain an actual energy deposition mode type; the actual energy deposition mode types include that the particles do not deposit energy in the scintillators, the particles only deposit energy in the second layer of scintillators, the particles only deposit energy in the first layer of scintillators and the particles have energy deposition in the two layers of scintillators, and the tritium beta rays are determined according to the actual energy deposition mode types. According to the invention, accurate measurement of tritium water can be realized.

The invention discloses a target detection network radiation hardening method for a space spacecraft AI chip, and belongs to the technical field of neural network radiation resistance. The method comprises the following steps: acquiring a target detection network model; a Dropout enhancement model and an exponential bit quantization optimization model are adopted respectively; and carrying out target detection in a space environment by adopting the optimized model. According to the method, the robustness of the neural network in the space radiation environment can be remarkably improved, the reasoning precision and speed of the model can be kept, the problem of reliable operation of the deep learning model in the space environment is solved, and the stability and task success rate of a spacecraft intelligent system are optimized. Aiming at the problem of single event upset caused by high-energy particle radiation in a space environment, the invention provides a training-reasoning collaborative optimization strategy, and provides reliable guarantee for AI application on a spacecraft.

The invention discloses a high-energy particle position sensitive detector based on scintillator strips, and the detector is characterized in that the detector comprises a housing which is internally provided with a photoelectric device circuit board, a signal amplifier circuit board, and a scintillator strip array; the scintillator strip array comprises a plurality of cuboid scintillator strips with square end surfaces; the scintillator strips are arranged in four layers, and the scintillator strips in each layer are sequentially and adjacently arranged in parallel at an inclined angle of 45 degrees, so that the square end surfaces of the scintillator strips in the layer form a zigzag plane; two of the four layers are stacked up and down to form a first array unit, the other two layers are stacked up and down to form a second array unit, the square detection planes of the first array unit and the second array unit are parallel, and the length direction of the scintillator strips in the first array unit is perpendicular to the length direction of the scintillator strips in the second array unit; one end of each scintillator strip is connected with a photoelectric device on the photoelectric device circuit board; and the signal amplifier circuit board is connected with the photoelectric device circuit board.

The invention discloses a vacuum coating process suitable for an ultrathin film layer circuit board and a coating device thereof, and relates to the technical field of vacuum coating. Comprising the following steps: transferring a circuit board substrate to a vacuum chamber, inputting argon into the vacuum chamber, ionizing the argon into argon ions with positive charges, accelerating the argon ions with positive charges to move towards the surface of a target material with negative charges under the action of an electric field, and knocking out evaporated substance atoms or molecules on the surface of the target material. Positively charged argon ions bombard the surface of the target material after being accelerated by an electric field, so that molecules of an evaporation substance on the target material release high-energy particle flow with high kinetic energy, and the particles move along irregular paths in a plasma environment to effectively cover fine gaps, edges and three-dimensional surfaces of a complex structure of a circuit board, so that the surface of the target material is effectively protected. And the particles can quickly and uniformly form an ultrathin film layer on the surface of the circuit board, so that the probability of non-uniform film thickness distribution caused by vapor natural deposition film coating is reduced, and the film coating effect of the device is improved.

Methods and systems are disclosed that enhance the yield and speed of emission and control the spectral and angular emission of light emitted by materials under irradiation by high-energy particles through a process known as scintillation. In each case, a photonic structure (of nano- or micron-scale feature sizes) is integrated with a scintillating material, and the photonic structure enhances the yield or controls the spectrum of the material. Various embodiments of this technology and practical demonstrations are disclosed.

The invention belongs to the technical field of plastic scintillators, and particularly relates to a polyurethane-based scintillator and a preparation method and application thereof. The invention provides a polyurethane-based scintillator. The polyurethane-based scintillator comprises a polyurethane matrix, a scintillating agent and a wave shifting agent, wherein the scintillating agent and the wave shifting agent are doped in the polyurethane matrix. Polyurethane is selected as a matrix, and certain self-repairing performance and flexibility are provided for the polyurethane-based scintillator. The doped scintillator can absorb energy of high-energy particles or rays and convert the energy into light energy; the doped wave shifting agent enables the wavelength of the emitted light to avoid the absorption wave band of the scintillator, thereby reducing the self-absorption and improving the output efficiency of the light. The flexible polyurethane-based scintillator with the self-repairing capability is prepared by doping the scintillator and the wave shifting agent into the polyurethane matrix.

The invention relates to a data migration method for wafer storage unit physical damage caused by high-energy particles, which belongs to the technical field of data processing, and comprises the following steps: monitoring a storage unit in real time to judge whether wafer physical damage caused by high-energy particle impact exists or not; if the physical damage exists, determining a damage radiation area by taking a damage point as a center; data, meeting a preset migration condition, in the damaged radiation area serves as data to be migrated, the data to be migrated are migrated to a safe area of the storage unit, and the safe area at least meets the condition that the safe area is not overlapped with any damaged radiation area determined before the current time. The method has the advantage that the active data preservation effect on the damaged data is realized aiming at the physical damage of the wafer storage unit caused by the high-energy particles.

This invention relates to the field of power semiconductor technology, specifically to an IGBT device resistant to single-event radiation and its fabrication method. By setting a P-type buried layer region at the bottom of the second trench, the strong electric field at the bottom of the trench is effectively weakened. Simultaneously, the P-type buried layer provides additional hole pathways, accelerating the extraction process of transient electron-hole pairs generated after high-energy particle incident, thereby effectively reducing the risk of single-event burn-out and improving the reliability of the device under irradiation. Furthermore, by introducing an N-type buried layer region at the bottom of the first trench, the electron injection effect is enhanced, increasing the carrier concentration in the on-state and reducing the on-state voltage drop. This structure also helps suppress the accumulation of holes below the gate during single-event incident, weakening the transient high electric field below the gate and improving the device's single-event tolerance. By reducing the depth of the first trench, the gate capacitance of the device can be effectively reduced, increasing the switching speed and reducing switching losses. In summary, this invention maintains radiation resistance while also ensuring high-frequency electrical performance.

The invention discloses a 10 MeV-level high-brightness ultrafast electron beam source based on quasi-linear laser wake field acceleration and a generation device thereof. Miniaturized repetition frequency ten-megawatt-level femtosecond laser interacts with a gas target capable of generating special gas flow distribution; based on a new quasi-linear laser wake field electron acceleration mechanism, the generation of a 10 MeV-level high-brightness high-performance ultrafast electron beam source can be accelerated. The device effectively solves the problem that it is difficult to accelerate generation of ultrafast electron beams with low energy dispersion, low emittance, high flow intensity, femtosecond pulse width, high brightness and high performance in a sub-ten-megawatt femtosecond laser driving wake field. Therefore, the method is expected to be widely applied to advanced fields such as ultrafast electron diffraction imaging and pumping detection, laser wake field and plasma diagnosis and measurement, high-energy particle acceleration, novel ultrafast coherent radiation source generation and the like.

The invention discloses a high-load transparent rare earth complex organic glass scintillator as well as a preparation method and application thereof. The scintillator comprises a polymer matrix and an ionic rare earth complex dispersed in the polymer matrix, the rare earth complex comprises coordination anions and ionic liquid cations, the coordination anions comprise rare earth ions and organic ligands, and the loading capacity of the rare earth complex in the polymer matrix can reach 80-90 wt%. According to the scintillator, an ionic liquid is introduced to construct an ionic supramolecular structure, effective isolation of a luminescence center is realized by utilizing steric hindrance and a charge shielding effect, concentration quenching is inhibited, and compatibility with a matrix is enhanced, so that the material still keeps transparency of 90% or above under an ultrahigh load. The maximum radiation luminous intensity of the scintillator is 23.9 times that of commercial LYSO, the lower detection limit is as low as 56nGy / s, and the scintillator is suitable for the fields of high-energy particle detection, X-ray imaging and the like.

The embodiment of the specification provides a multi-source high-energy particle detection data fusion method and device, wherein the multi-source high-energy particle detection data fusion method comprises the following steps: obtaining initial detection data, performing geomagnetic coordinate conversion based on the initial detection data to determine a coordinate conversion result; determining a baseline model based on the coordinate conversion result, determining a fluctuation model based on the baseline model; establishing a data calibration model based on the baseline model and the fluctuation model; determining calibration data based on the data calibration model, determining a calibration coefficient based on the calibration data; performing data conversion based on the calibration coefficient and the data calibration model to determine fusion data. By increasing the calibration of fluctuation data at the data calibration level, the fluctuation detection data can be retained in the data fusion aspect, and the method has a wider application scenario.

The invention provides a neodymium-iron-boron magnet, a preparation method thereof, a high-radiation-resistance bonded neodymium-iron-boron magnet and application. The neodymium-iron-boron magnet is of a core-shell structure. The core-shell structure comprises an inner core, an inner shielding layer and an outer protection layer, wherein the inner shielding layer and the outer protection layer sequentially cover the surface of the inner core. Wherein the inner core comprises a neodymium iron boron magnetic material, the inner shielding layer comprises gadolinium oxide, and the outer protection layer comprises boride. According to the method, efficient cascade shielding of high-energy particles such as neutrons and gamma rays is formed through the nuclear physical shielding principle (the neutron capture effect of the gadolinium element and the gamma ray scattering function of boron nitride), the radiation resistance of the magnet is greatly improved, and the prepared neodymium-iron-boron magnet has the advantages of light weight and low-temperature forming; and the synergistic improvement of high radiation resistance and excellent magnetic performance can be met at the same time. The high-radiation-resistance bonded neodymium-iron-boron magnet prepared based on the neodymium-iron-boron magnet can keep stable magnetic performance in an extreme environment with an accumulated radiation dose of more than 1MGy.

The present invention relates to a numerical calculation method for the long-distance transmission of relativistic charged particle beams, which solves the problems of inaccurate calculation methods of empirical formulas for the long-distance transmission of high-energy particle beams and great difficulty in numerical calculation in the current fields of space magnetic field measurement and accelerator system design. First, set the initial parameters of the particle beam in the laboratory reference frame, and obtain the positions and velocities of all particles after emitting a single pulse under these parameters. Then, according to the Lorentz transformation formula, transform the positions, velocities of all particles and the external electromagnetic field into an inertial reference frame with a certain intermediate velocity of particle motion. Next, perform numerical calculations in the new reference frame to obtain the positions and velocities of the particles in the final state. Finally, according to the Lorentz transformation formula, transform the positions and velocities of the particles in the final state in the new inertial reference frame back to the laboratory reference frame, and the state of the particle beam in the final state of the laboratory reference frame can be analyzed.

The application provides a spatial high-energy particle detection array film which can be greatly stretched and attached to a complex curved surface and belongs to the technical field of detection. A peripheral support frame is arranged on a flexible base and is used for mounting, limiting, pre-tensioning or fixing with a target curved surface; a middle part is a deformable working area, a plurality of detection unit rigid islands are arranged in the working area; electrical connection is realized through liquid metal bridging wires between adjacent detection unit rigid islands; an upper packaging layer, a lower packaging layer and an edge flexible lead-out interface are arranged outside. The application realizes the combination of "high-performance detection unit" and "overall large deformation attachment ability" by limiting the detection function in the local rigid island and mainly distributing the structural deformation to the liquid metal bridging area.

The invention discloses a repetition frequency strong field laser system and an implementation method thereof. The laser outputs multiple paths of output laser with the same repetition frequency and equal-interval time delay, the output laser is focused on a target through a focusing lens group, and the repetition frequency of a generated high-energy particle beam is multiple times of the repetition frequency of the output laser; by utilizing a mechanism that the direction of a generated particle beam is vertical to a target back under the condition of high-contrast laser in a particle accelerated target back normal sheath accelerated TNSA mechanism, the invention adopts multiple paths of output laser, regulates and controls the laser time sequence, does not change the repetition frequency of the output laser, and enables the multiple paths of output laser with staggered time sequence to act on a target in sequence, so that the target is accelerated. The repetition frequency of an emergent particle beam is improved; the laser heat management problem is not increased, the repetition frequency of the particle beam is improved, and the repetition frequency of the particle beam can be further improved by further increasing the number of lasers and reasonably regulating and controlling the laser time.

The present disclosure provides a method for restoring the photoelectric parameters of a photoelectric imaging device after on-orbit operation, wherein the photoelectric imaging device is damaged by radiation from high-energy particles after on-orbit operation, comprising: S1, placing the photoelectric imaging device in a darkroom cavity whose surface is covered with a shading unit; S2, adjusting the darkroom cavity to a preset temperature using a temperature control system; the temperature control system at least includes a signal processing circuit, a thermistor, a heat dissipation element, a heating element, an analog-to-digital converter, and a multi-way analog switch; S3, annealing the photoelectric imaging device for a preset time, and recording the annealing condition information; S4, setting test parameters using a control module in a test system, and collecting image data of the photoelectric imaging device at different integration times; S5, processing the image data using a computer to obtain key parameter data, and restoring the photoelectric parameters of the photoelectric imaging device based on the annealing condition information and the key parameter data.

The application discloses a satellite orbit space environment disturbance coping method, equipment and computer program product. The method comprises the following steps: acquiring current position data and current space environment data of a target orbit, wherein the current space environment data comprises a first high-energy particle integrated flux at a target position of a high-energy particle flux and a first high-altitude atmospheric daily average atmospheric density; querying a second high-energy particle integrated flux at the target position of the high-energy particle flux and a second high-altitude atmospheric daily average atmospheric density when the target orbit environment is calm according to the current position data; calculating a high-energy particle radiation environment relative disturbance amount and a high-altitude atmospheric density maximum relative disturbance amount of the target orbit; determining a current high-energy particle radiation environment disturbance degree and a current atmospheric environment disturbance degree in combination with a disturbance degree discrimination range; and generating a risk coping suggestion. The application can accurately understand the disturbance situation of a spacecraft operating environment and improve the safety of the spacecraft in-orbit operation.

The utility model provides automation equipment for testing light output of a scintillator. The automation equipment comprises a shielding box body. The shielding box body is a hollow box body, the top of the shielding box body is provided with an exit port, the shielding box body is internally provided with a lifting frame, the lifting frame is arranged at the bottom of the shielding box body, the upper side of the lifting frame is provided with a detector, and a scintillator to be detected is arranged on the top surface of the detector. And a high-energy particle generator is arranged on the upper side of the shielding box body and emits high-energy particles to the to-be-detected scintillator in the shielding box body from the exit port. The device can adapt to the evaluation of scintillators with different shapes and sizes, improves the adaptability of the device, and meets the diversified test requirements.

This application provides a low-energy particle analysis system with autonomous numbering and identification capabilities, including a low-energy ion analyzer and a low-energy electron analyzer, both of which utilize the same FPGA control program. The FPGA design incorporates component grouping measurement to achieve multi-component detection within a unit measurement time. An instrument number interface is added to the interface for reading the instrument number interface level. A numbering identification and control module is added to identify the current instrument type and generate instrument identification parameters. This module is used to acquire different numbers of engineering parameters when the instrument type is either a low-energy ion analyzer or a low-energy electron analyzer. It also controls the reception of commands from the device corresponding to the current FPGA configuration and controls the output of data packets corresponding to the current FPGA configuration. This system programs the same FPGA executable code onto both the low-energy ion analyzer and the low-energy electron analyzer, achieving FPGA configuration adaptiveness.

The invention discloses an ion optical system for extracting an extremely-low-energy parallel high-current ion beam, which comprises a plasma electrode, an extraction electrode, a suppression electrode, a focusing electrode, a speed reduction electrode I, a speed reduction electrode II and an annular magnet, the plasma electrode, the extraction electrode, the suppression electrode, the focusing electrode, the speed reduction electrode I and the speed reduction electrode II are coaxially mounted in sequence; the annular magnet is positioned between the speed reduction electrode I and the speed reduction electrode II; the plasma electrode is a conical electrode, and a through hole is formed in the center; the extraction electrode is formed by combining a conical electrode and an annular electrode, a through hole is formed in the center of the conical electrode, the conical electrode is located on one side of the plasma electrode, and the annular electrode is located on one side of the suppression electrode; the suppression electrode, the focusing electrode, the deceleration electrode I and the deceleration electrode II are annular electrodes. According to the system, parallel high-current ion beams can be obtained, and a basis can be provided for ground calibration work of a space low-energy particle detector.

This disclosure provides a method, apparatus, electronic device, and medium for reconstructing the dose distribution of a particle irradiation target area. The method includes: monitoring the irradiation information of particles on a monitoring plane along the incident path, including beam spot position, beam spot size, and dose corresponding to each position, wherein the particles include particles of various energies; calculating the dose of particles of different energies at different depth planes in the target area based on the particle dose ratio of particles of different energies at different depth planes in the target area to the monitoring plane; calculating the particle dose of each energy particle at each position in the target area at different depth planes based on the particle distribution pattern of each energy particle on the monitoring plane; constructing a planar dose model of the target area at different depth planes based on the particle dose of each energy particle at each position in the target area at different depth planes, and reconstructing a three-dimensional dose model by superimposing the models; and fusing the three-dimensional dose model with a three-dimensional image of the target area to obtain a three-dimensional particle dose distribution model of the target area.

The invention relates to the technical field of irradiation processing, and provides irradiation equipment, application of the irradiation equipment and a control method of the irradiation equipment, the irradiation equipment is used for processing diamond, and the irradiation equipment comprises an irradiation device, a clamping device and a cooling liquid circulating device. The irradiation device is used for generating a high-energy particle beam; an irradiation area is formed in the clamping device, the clamping device is provided with a plurality of clamping grooves which are formed in the irradiation area and open towards the irradiation device, at least one diamond is placed in each clamping groove, and a liquid cooling flow channel is formed in the clamping device; and the cooling liquid circulating device is communicated with the liquid cooling flow channel. According to the irradiation equipment provided by the invention, the production efficiency of diamond irradiation processing can be improved.

The application discloses a medium laser acceleration system and method, the medium laser acceleration system comprises a laser system for providing a high-power laser pulse; a particle injection source for providing a charged particle beam; a medium laser acceleration device for generating a high-gradient acceleration electric field; an information acquisition module for acquiring parameters of the particle beam; a diagnosis module for diagnosing a state of the particle beam and electromagnetic field transmission characteristics of the medium laser acceleration device; and a controller connected to an output end of the diagnosis module and a controlled end of the laser system, for acquiring a preset energy value of the high-energy particle beam and determining a target power and time sequence of the laser pulse according to the preset energy value. The application further provides a medium laser acceleration method based on the above medium laser acceleration system. Compared with prior art solutions, the application can provide a high-energy particle beam while reducing the size of a particle accelerator.

The invention discloses an integrated high-energy particle detector for a magnetic confinement fusion device, which mainly comprises a cross collimator and a scintillator plate, the cross collimator is provided with a front collimation hole, a rear collimation hole, an upper collimation hole and a lower collimation hole, the upper collimation hole, the lower collimation hole, the front collimation hole and the rear collimation hole are arranged in a cross manner, and the top of the upper collimation hole is provided with an electronic stripping film. Ions with different energies and throwing angles pass through the front and rear collimation holes, so as to hit different coordinates on the scintillator to emit scintillation light; the high-energy neutral particles which are not electrified sequentially pass through the lower collimation hole and the upper collimation hole in a straight line, then pass through the electron stripping film, are stripped with electrons and become ions, and then do Ramor cyclotron motion in a magnetic field and strike the scintillator to emit scintillation light. The integrated high-energy particle detector can detect high-energy ions and high-energy neutral particles in the magnetic confinement fusion device at the same time.

The application discloses an integrated high-energy particle detector for a magnetic confinement fusion device, mainly comprising a cross collimator and a scintillator plate, front, rear, upper and lower collimating holes are formed in the cross collimator, the upper and lower collimating holes are arranged in a cross shape with the front and rear collimating holes, and an electron stripping film is installed on the top of the upper collimating hole. Ions with different energies and pitch angles pass through the front and rear collimating holes, thereby hitting different coordinates on the scintillator to emit scintillation light; for high-energy neutral particles without electricity, the high-energy neutral particles pass through the lower collimating hole and the upper collimating hole in sequence, then pass through the electron stripping film to be stripped of electrons to become ions, and then make Larmor cyclotron motion in a magnetic field and hit the scintillator to emit scintillation light, therefore, the integrated high-energy particle detector can simultaneously detect high-energy ions and high-energy neutral particles in the magnetic confinement fusion device.

The present application relates to a kind of based on graph neural network's neutron scattering experimental sample temperature field monitoring method, comprising the following steps: step one, research the attenuation law of high-energy particle environment to sample surface radiation energy, step two, construct the hyperspectral imaging model of sample surface radiation, step three, using multispectral radiation thermometry theory, complete the numerical reconstruction of sample surface temperature field under high-energy particle environment;Step four, combined with hyperspectral numerical image data, construct the surface temperature field measurement proxy model based on graph neural network;The purpose of the present application is to provide a kind of based on graph neural network proxy model's neutron scattering experimental sample surface temperature field monitoring method, realize the accurate measurement of sample surface temperature field under high-energy particle environment.

The application discloses a deep space vehicle intelligent decision-making method and system based on space-based edge computing. The method comprises the following steps: collecting real-time trigger data obtained by each probe arranged on an in-orbit deep space vehicle according to a corresponding real-time trigger threshold; calculating the correlation degree of the real-time trigger data between each two probes, and determining whether there is abnormal real-time trigger data based on the correlation degree; if there is abnormal real-time trigger data, the abnormal real-time trigger data that does not meet the first preset condition of light variation curve characteristics and does not meet the second preset condition of spectral characteristics is removed; based on all the remaining real-time trigger data after removal, the source direction of the cosmic high-energy particle stream relative to the deep space vehicle is calculated, and the source direction and all the remaining real-time trigger data after removal are stored in a space storage unit of the deep space vehicle. The application can reduce invalid data storage and downlink, optimize the utilization efficiency of communication bandwidth, and improve the autonomy and adaptability of deep space exploration tasks.