The article presents a method for experimentally determining the fundamental parameter of interaction between a broadband x-ray spectrum and a material-the ratio of the effective attenuation coefficient μef of the primary spectrum and the attenuation coefficient μi of the fluorescence line of the i-th element. The determination of the fundamental parameter is necessary to justify the magnitude of the uncertainty of the concentration values found from the intensity of the fluorescence lines. The method is based on the known dependence of the intensity of x-ray fluorescence on the angles of entry φ and exit ψ of radiation from the surface of the sample. At a constant scattering angle 2θ = φ + ψ, a series of measurements of the x-ray spectrum are made with different values of the angle ψk and the integrated fluorescence intensity I(ψk) is measured. Varying the angle ψk in the range from 0° to 90° allows, when measuring a film on a substrate, to move from the "saturated layer" model to the thin film model with all intermediate stages. By fitting the experimental dependence I(ψk), the values μiμef and μef·D are determined, where D is the surface density. The objects of the study were single-component standards as well as zirconium films and nickel foils on single-crystalline silicon substrates. Spectral measurements were performed on an EDXRF spectrometer with SDD X-100 (Amptek). The ψk angle was set in 1° increments by rotating the sample on an HGZ (Carl Zeiss) goniometer; the spectrum accumulation time was 600 s. For single-component standards of zirconium, nickel iron, and titanium, the μiμef values were determined with a relative error of 3%. The influence of the broadband spectrum shape on the μiμef ratio and the λef (effective wavelength of the primary broadband spectrum) value was established: (1) a decrease in the voltage on the tube from 30 to 25 kV leads to an increase in λef for zirconium from 0.535 to 0.656 Å, for nickel from 0.694 to 1.004 Å, and for iron from 1.135 to 1.408 Å; (2) the influence of the Cu-Kα artifact line on the μiμef ratio was revealed: for iron and nickel, which have absorption jumps on opposite sides of this line, the μiμef values differ by more than two times due to the effective excitation of iron fluorescence by the Cu-Kα line. For nickel foils with a thickness of 6-12 μm, the values of μiμef and surface density were measured without the use of standards. The μiμef values of the foils are close to the nickel standard, and the surface density corresponds to the reference values. The relative measurement error does not exceed 5%. For thin zirconium films (0.2-6 μm), it was not possible to detect the theoretically predicted increase in λef with decreasing film thickness. The found values of surface density correspond to the reference values within 10% without the use of standards. The values of the parameters μiμef and μef·D can be determined for a multicomponent film, serve as a criterion for selecting film standards of similar composition and thickness, and be used to justify the uncertainty of measurement results by calibrations.
An experimental and simulation study of the balanced quartz tuning fork (QTF) force sensor in an atmospheric environment is presented. The experimental results demonstrate that a QTF force sensor with a balanced structure shows a significant improvement in the Q-factor in an atmospheric environment. With a rational configuration of the QTF probe structure, the Q-factor can be increased by 2-3 times compared to that of the unbalanced ones, even when the length of the attached probe tip (tungsten wire) is longer than 2.5 mm. More precisely, the Q-factor can reach 3000 when the tip length is around 1.0 mm. For a probe length of about 3.5 mm, the Q-factor is ∼1800, which also suits the working of the atomic force microscope (AFM) and shows more stability than the length near 1.0 mm. Nevertheless, the highest Q-factor of the QTF probe does not occur under the most symmetric condition. To explain these results, simplified models associated with the basic QTF probe working situation were simulated using the commercial software COMSOL Multiphysics®. By analyzing these results, we elucidated the mechanism of the QTF probe working in an atmospheric environment and some of its vibration modes connected with its Q-factor. According to the experimental and simulation study results, the balanced QTF probe exhibits a significantly higher Q-factor than conventional ones. The probe tip, with its length near 1.0 mm or 3.5 mm, can achieve an opportune Q-factor for AFM, demonstrating its potential for further improving the performance of QTF probes for atomic force microscopes under ambient conditions.
The Toroidal x-ray Imager (TXI) is a multi-channel x-ray imager with a pseudo-Wolter configuration, allowing a large field of view and a high resolution for plasma characterization. The imager has three energy bands centered at 8.7, 13, and 17.5 keV. We propose an innovative solution to fulfill the scientific requirements of TXI by combining two aperiodic multilayer coatings with different bandwidths, a narrowband on one mirror and a broadband on the other mirror for each channel. This article presents the experimental development of the W/SiC multilayer coatings on the toroidal mirrors of TXI. The coatings were deposited by the magnetron sputtering technique and characterized at-wavelength in the Physikalisch-Technische Bundesanstalt laboratory at BESSY II and at the ESRF synchrotron. The measurements indicate a good agreement with the simulations using a two-layer model for the W/SiC multilayers. Interfacial defects were modeled using roughness values of 0.3-0.4 nm at each interface. We also report on the final performance of the instrument, which was estimated using a ray-tracing code including a simulation of the multilayers based on the fit of experimental mirror reflectance spectra. Finally, we discuss the effect of the field of view on each criterion: the total throughput, the spectral purity, and the spatial uniformity in the detector plane for each channel of TXI.
The series capacitor compensation technology can improve the transmission capacity of long-distance transmission lines and the stability of the power grid. However, it faces limitations due to quick failure of the mainstream capacitor protection device, the metal oxide varistor, after multiple actions. To improve the conduction performance and service life of the fast protection device for series compensation capacitors, this paper proposes a long-spacing air gap switch (LAGS) based on double capillary discharge triggered plasma jet and focuses on the influence of microcavity structure parameters on trigger characteristics of the LAGS. The results show that the conduction performance of LAGS is optimal under the structure of a 20-25 mm long secondary cavity, a 4 or 5 mm long primary cavity, and a 10 mm thick ground electrode. Under the optimized parameters, the switch can be conducted stably for about 110 times at a 1.4 kV trigger voltage. Due to the recoil effect of the secondary cavity on the primary cavity, the primary cavity is severely eroded, which lowers the density and velocity of initial plasma, making it hard to penetrate the gap. By transforming the middle electrode into a 2-0.6 mm contracted shape, the recoil effect can be mitigated without reducing trigger energy. Therefore, at a 1.4 kV trigger voltage, the service life of the gap switch can be extended to 220 times with a less than 500 μs conduction delay. The research results indicate that a 10 cm long LAGS is expected to meet the sub-millisecond and reusable conduction requirements of the series compensation protection system.
The data quality of an aeromagnetic survey is determined by the compensation for the magnetic interference of the aircraft. In existing neural-network-based magnetic compensation, the dimensionality of the input parameters of the magnetic interference network is high, and the determination of the input depends on personal experience and preliminary experiments, increasing the probability of overfitting and compensation instability. In addition, the interference features vary with time, while the existing models do not have temporal memory, resulting in poor generalization of the interference prediction. In addressing this issue, a novel compensation model architecture based on autoencoder bidirectional long short-term memory is proposed to adaptively extract features and reduce the parameter dimensionality, and thus enhance self-adaptability. In addition, the temporal dependencies among historical magnetic data along positive and negative directions are learned to effectively reduce the prediction error. Furthermore, two loss functions are defined to mitigate the degradation of prediction performance due to the dataset shift between calibration and measurement flights and to reduce the sensitivity of the interference prediction to geomagnetic noise. To verify the proposed method, we developed a dedicated compensator and built a flight test platform. The results show that the improvement ratio of magnetic interference on the verification flight for our method reaches 28.36, which is significantly higher than the ratios for the existing methods and the state-of-the-art commercial compensator, resulting in better interference mitigation. From the calibration flight to the verification flight, the improvement ratio of our method decreases by only 2%, resulting in a satisfactory generalization.
The MMX InfraRed Spectrometer (MIRS) is a spectro-imager on board the Japan Aerospace Exploration Agency Martian Moons eXploration mission, set to launch in 2026, to investigate the origin of the Martian moons, Phobos and Deimos, as well as the Martian atmosphere and surface. MIRS, operating in the 0.9-3.6 μm wavelength range, is designed to identify and map minerals, ices, and organic compounds on the Martian moons, while also monitoring water vapor and dust in Mars's atmosphere. This paper details the ground calibration and performance evaluation of the MIRS Flight Model, conducted at the Laboratory for Instrumentation and Research in Astrophysics at the Paris Observatory during the thermal-vacuum test campaign at the end of 2023. A detailed description of the apparatus and the procedures used during the campaign is provided. The calibration campaign tested the instrument's thermal response and radiometric performance, ensuring compliance with stringent mission requirements. The tests demonstrated MIRS's capability to deliver high-resolution spectral data, fulfilling critical scientific and technical objectives. The preliminary results indicate MIRS's readiness for in-flight operations and its potential to contribute significantly to the understanding of the Mars system.
This paper presents a novel non-contact magnetic rotary-driven piezoelectric energy harvester (NC-MRPEH). Unlike traditional contact-driven devices, this harvester utilizes a non-contact magnetic coupling structure to achieve efficient energy conversion. The research adopts a combined approach of theoretical modeling and experimental verification to systematically investigate the effects of key parameters, such as the number and arrangement of rotating magnets, rotational speed, magnet spacing, rotational radius, number of fixed magnets, and load resistance on the output performance of the NC-MRPEH. The results show that the number of rotating magnets affects the peak power, rotational speed, and range; at low speeds, it is better to arrange the magnets in the same polarity, and at high speeds, opposite polarities are more favorable; the output power increases with the decrease in the spacing between the rotating and fixed magnets, and the influence of the rotational radius on it is less than that of the spacing, and mode 2 is negatively affected; the number of fixed magnets (when the space is fixed) and the load resistance (there is an optimal value) also have an effect. In the experiment, a single piezoelectric oscillator NC-MRPEH with specific parameters (eight rotating magnets, spacing 20 mm, radius 21 mm, mode 2, 110 kΩ resistor) successfully lit up 70 LEDs, confirming its charging efficiency and practicality.
This study introduces a novel defect detection method based on induced magnetic field measurements. The technique employs a millimeter-scale permanent magnet as the excitation source and utilizes a high-precision tunnel magnetoresistance sensor to detect perturbations of the induced magnetic field generated by eddy currents, thereby identifying defects. In contrast to conventional eddy current testing, the proposed method eliminates the need for excitation coils, significantly reducing the size and weight of the detection apparatus while offering increased detection accuracy. Vector analysis is conducted through both experiments and numerical simulations, and the signal characteristics are further interpreted using an equivalent parallel circuit model of eddy current flow. An experimental setup is developed to detect microdefects, successfully identifying flaws as small as 10 μm, thus demonstrating the feasibility of the proposed method. Additionally, the influences of four key parameters, namely, the defect diameter, the rotational tangential speed of the copper plate, the skin depth, and the lift-off distance, on the detection performance are systematically studied via both experiments and simulations. The results indicate that smaller defects substantially increase the difficulty of detection, higher motion velocity increases the detection sensitivity, but at the expense of reducing detection depth, and a lift-off distance of 0.2 mm is identified as better. Owing to its compact structure and high precision, the proposed sensor system shows great potential for practical applications in non-destructive testing engineering, such as fatigue crack detection of non-ferromagnetic high-manganese steel commonly used in high-speed railway tracks.
Microgrippers are precision actuation devices designed for the capture, release, and manipulation of microscale objects. The key challenge in achieving high-precision micro-grasping operations lies in suppressing the parasitic displacement of the gripping jaws. This paper proposes a two-stage amplification mechanism with low parasitic displacement to achieve high-precision micro-grasping operations of the microgripper. When the clamping displacement direction of the microgripper aligns with the desired motion direction, parasitic displacement is minimized. The second-stage amplification mechanism is directly connected to the microgripper's output end, which determines the magnitude of parasitic displacement. Among these, a symmetrical compound parallelogram mechanism with flexure hinges is introduced as the second stage to fundamentally minimize parasitic displacement. Simulation results show that the proposed externally actuated microgripper with displacement compensation achieves a parasitic displacement rate of only 0.158%. Experimental results demonstrate that under an air pressure of 0.6 MPa, the prototype achieves a total output displacement of 490.3 μm, a total amplification ratio of 29.1, and a measured first-order natural frequency of 1625 Hz. The experimental results validate the rationality of the design, indicating the potential of this microgripper for micromanipulation tasks requiring both a large stroke and high precision.
To resolve the issue of high-quality propagation and amplification of orbital angular momentum modes derived from the Raman effect and doped materials, a photonic crystal fiber amplifier, which can amplify orbital angular momentum modes, is proposed in this paper. Through modifying the structure and doping material concentration of the amplifier, the performance of the amplifier is optimized and then systematically investigated through finite element method simulations using COMSOL Multiphysics® (multiphysics simulation software) version 6.2. The results reveal that the amplifier can realize the steady propagation of 38 orbital angular momentum (OAM) modes, and the amplifier exhibits excellent amplification performance, characterized by high mode gain and low threshold power. The threshold power of all modes does not exceed 250 mW, which is conducive to signal amplification. As the pump light has an incident power of 300 mW, a wavelength of 1450 nm, and a wavelength of the OAM signal of 1550 nm, the maximum mode gain of 160.87 dB can be obtained. Compared with the existing orbital angular momentum amplifier, the signal gain has been greatly improved. The proposed amplifier has the advantages of high gain, low threshold power, and a large number of amplified modes, which has significant applications in achieving long-distance stable propagation of OAM and enhancing the capacity of optical fiber communication systems.
The simultaneous generation of ultrahigh pressure and temperature in a multi-anvil press is crucial for studying planetary interiors and synthesizing novel materials. However, this goal is fundamentally challenged by severe thermal losses for the small sample-cell assembly, especially at ultrahigh pressures above 40 GPa. Our study employs a coupled thermal-electrical finite element model, validated by experimental data, to investigate the principles for enhancing the temperature generation capacity of an ultrahigh-pressure assembly. Our finite element model well reproduces the experimental heating results at ultrahigh pressures. The simulation analysis demonstrates the radial alumina insulation sleeve as the most significant factor for improving heating efficiency, while enlarging the diameter of the titanium carbide electrode is critical for enhancing interfacial stability. Counterintuitively, the adoption of high-thermal-conductivity sintered diamond anvils, while demanding more power, serves as an essential safety mechanism by preventing the melting of sintered diamond anvil truncations through the efficient heat dissipation. The combined optimization of these factors alleviates previous thermal bottlenecks and allows the assembly to reach noticeably higher temperatures (∼4000 K). This work thereby provides a rational framework and practical strategies for achieving more extreme ultrahigh temperature conditions at ultrahigh pressures through integrated thermal management.
Deep-depletion charge-coupled device (CCD) cameras can be used as x-ray spectrometers if the flux is limited to significantly less than one photon per pixel. The charge that is created by the absorbed photon is proportional to the x-ray energy, and consequently, the histogram of the CCD-sensor readout (in the limit of no noise and large pixel size) is a strictly linear spectrum. If the quantum efficiency of the detector, the attenuation of x-rays from the source to the detector, and the overall geometry of the setup are known, one can also calculate the absolute flux for a given photon energy from the source. We describe the efficient use of a commercial deep-depletion CCD camera as an absolutely calibrated x-ray spectrometer for the determination of laser-to-x-ray conversion efficiencies with the Z-Petawatt and Z-Beamlet lasers [P. Rambo et al., Proc. SPIE 10014, 100140Z (2016)] at Sandia National Laboratories. We explain procedures to reverse intrinsic degradations of x-ray induced pixel brightness and to mitigate external noise, and we identify spectral artifacts that are generated inside the detector.
This paper presents the new thermographic inversion code DELVER (Divertor Energy Load Versatile EstimatoR). Its task is to calculate the heat flux distribution on plasma-facing components from the evolution of surface temperature derived from infrared camera measurements. For operational campaign 2 of Wendelstein 7-X, water-cooled high-heat flux divertors made of layers of different materials have been installed into the plasma vessel. The previously employed explicit thermographic inversion code, THEODOR, was deemed insufficient to model these accurately due to the missing capability of defining multiple material layers. This motivated the development of DELVER, which improves upon explicit THEODOR in further aspects by handling 1D, 2D, and 3D modeling with flexible boundary conditions, an implicit solver, arbitrary functional temperature dependency of the orthotropic thermal properties of the materials, and a non-equidistant orthogonal calculation grid. The two codes are being compared using a simple analytical model, the finite element solver ANSYS®, and finally, experimental heat flux calculated from the calorimetry and heat fluxes calculated from infrared measurements. In all test cases, good agreement between DELVER simulations and expected results is achieved.
A novel asymmetric structure of piezoelectric stick-slip actuator (PSSA) with chainlike compliant mechanism is designed, which satisfies the requirements of high-precision, long-stroke nano-scale motion control. The combined structure of asymmetric chainlike compliant mechanism with PSSA is used to enhance the compliance. Backward displacement is suppressed by chainlike piezoelectric stick-slip actuator (CPSSA). The CPSSA is designed to enlarge the single-step displacement and to improve the output performance. Subsequently, finite element analysis is employed to compute the parametric design of the structure. Then, the dynamic stiffness matrix analysis of the structure is given. Finally, an experimental system is constructed, and a range of test data are presented. The experimental findings demonstrate that the peak output speed of the actuator is 19.01 mm/s, while the horizontal loading capability and vertical loading capacity are determined to be 3.8 and 2.46 N, and the resolution is 56 nm, respectively. The effectiveness of the chainlike piezoelectric stick-slip actuator (CPSSA) is thereby verified.
A new molecular beam calibration facility, the MOlecular Beam for Instrument Utilization and Simulation (MOBIUS), has been developed to enable realistic, in situ testing and calibration of spaceborne neutral mass spectrometers. The facility is based on a differentially pumped beamline featuring a high-pressure, high-temperature nozzle source and modular diagnostic capabilities. MOBIUS is specifically engineered to reproduce the high-speed, directed neutral particle fluxes encountered by spacecraft in planetary exospheres and upper atmospheres. We demonstrate the system's performance by characterizing supersonic beams generated across multiple gases. When operating with seeded gas mixtures (hydrogen-argon), the facility reliably produces neutral beams in the 3-5 km s-1 range, successfully achieving the high relative velocities required for instruments such as the Strofio mass spectrometer onboard BepiColombo. Furthermore, neutral flux is verified to be on the order of 1015 cm-2 s-1, and the resulting beam profiles are confirmed to be uniform and well-collimated. These results establish MOBIUS as a complete and necessary testbed for accurately characterizing the response of instruments under relevant in-orbit conditions.
Microwave (MW) fields with strong field strength, ultralow phase-noise, and tunable polarization are crucial for stabilizing and manipulating ultracold polar molecules, which have emerged as a promising platform for quantum science. In this article, we present the design, characterization, and performance of a robust MW setup tailored for precise control of molecular states. This setup achieves a high electric field intensity of 6.9 kV/m in the near-field from a dual-feed waveguide antenna, enabling a Rabi frequency as high as 71 MHz for the rotational transition of sodium-potassium molecules. In addition, the low noise signal source and controlled electronics provide ultralow phase-noise and dynamically tunable polarization. Narrowband filters within the MW circuitry further reduce phase noise by more than 20 dB at 20 MHz offset frequency, ensuring prolonged one-body molecular lifetimes up to 10 s. We also show practical methods to measure the MW field strength and polarization using a simple homemade dipole probe and to characterize phase-noise down to -170 dBc/Hz using a commercial spectrum analyzer and a notch filter. Those capabilities allowed us to evaporatively cool our molecular sample to deep quantum degeneracy. Furthermore, the polarization tunability enabled the observation of field-linked resonances and facilitated the creation of field-linked tetramers. These techniques advance the study of ultracold polar molecules and broaden the potential applications of MW tools in other platforms of quantum science.
Conventional electromagnetic expanding ring technique requires increasing the driving current to achieve higher loading strain rates. However, the associated increase in Joule heating within the specimen ring can compromise the accuracy of dynamic mechanical property measurements. This paper proposes an electromagnetic expanding ring technique based on an external magnetic field modulation. By applying a steady-state magnetic field, the electromagnetic driving force is increased without raising the induced eddy current in the specimen ring, ultimately achieving high strain rate loading with low temperature rise in the specimen. Combining theoretical analysis, numerical simulations, and experimental validation, the influence of the external magnetic field on the dynamic response of the electromagnetic expanding ring specimen was investigated. Utilizing the newly proposed technique, stress-strain response and fracture strain of H62 brass under various loading conditions were successfully obtained, verifying the feasibility and reliability of the external magnetic field modulation method for achieving high strain rate and low temperature rise. Experimental results demonstrate that applying a 5.2 T external magnetic field under a 50 kA driving current more than doubles the specimen strain rate compared to the conventional method without external magnetic field. At similar strain rate levels, the specimen temperature at a strain of 0.1 decreased from 770 °C in conventional experiments to 240 °C in the new experiments, indicating significant mitigation of Joule heating. The new electromagnetic expanding ring technique provides an effective method for investigating the dynamic mechanical behavior of materials under high strain rates.
Laser ultrasound (LU) is a technique that uses a pump laser and a probe laser to optically generate and detect elastic waves in a material. Despite its advantages over traditional contact transducer-based ultrasound, industrial adoption has been limited by complex optical setups and the inability of multi-mode fibers to deliver a stable Gaussian profile for the pump laser. Here, we report a fully fiber-coupled thermoelastic LU system that uses an anti-resonant hollow-core single-mode fiber to deliver 1mJ nanosecond pulses of 1064nm light, while preserving the fundamental Gaussian mode (pump laser). When combined with a fiber-coupled interferometer (probe laser), a small, flexible, and environmentally robust sensor capable of optically generating and detecting high frequency broadband ultrasound is realized. We demonstrate such an LU system implemented in situ on a four-axis precision lathe. High-resolution thickness gauging is performed, before and after precision cutting, by exciting and measuring a zero-group velocity guided wave mode. The measurements are verified with ex-situ traceable coordinate measuring machine data. Mean absolute deviations of 0.1%, of nominal thickness, before cutting, and 0.2% and 0.3%, after stepped and tapered cuts, respectively, are reported. A theoretical background for thermoelastic ultrasound generation in an elastic waveguide is also presented. Attention is given to the effect of the pump laser profile on wave generation to elucidate the importance of using single-mode laser light. The fiber-coupled system demonstrated is well-suited for use in scientific and engineering sensing applications and facilitates the adoption of LU for industrial non-destructive testing.
The achievable performance of the complementary-filter-based parallel control for a compound dual-stage nano-positioning system is limited by its model-based sequential design structure. This study proposes a frequency-response-data-based optimization approach for the simultaneous and systematic design of the complementary-filter-based dual-feedback controller. The design procedure and corresponding Nyquist stability analysis are presented in detail. By directly utilizing frequency response data, the proposed method mitigates the effects of system identification errors. The controller design objective is formulated as a constrained optimization problem to achieve a flat amplitude frequency response with high control bandwidth. Comparative experiments conducted on a dual-stage nano-positioning system verify the effectiveness of the proposed approach. The proposed method reduces the root-mean-square tracking error from 70.6 nm using the baseline integral controller to 21.3 nm at 50 Hz sinusoidal tracking, demonstrating its clear superiority.
Infrared-blocking, aerogel-based scattering filters have a broad range of potential applications in astrophysics and planetary science instruments in the far-infrared, sub-millimeter, and microwave regimes. This paper demonstrates the ability of conductively loaded, polyimide aerogel filters to meet the mechanical and science instrument requirements for several experiments, including the Cosmology Large Angular Scale Surveyor, the Experiment for Cryogenic Large-Aperture Intensity Mapping, and the Sub-millimeter Solar Observation Lunar Volatiles Experiment. Thermal multi-physics simulations of the filters predict their performance when integrated into a cryogenic receiver. Prototype filters have survived cryogenic cycling to 4 K with no degradation in mechanical properties. Measurement of total hemispherical reflectance and transmittance as well as cryogenic tests of the aerogel filters in a full receiver context allows estimates of the integrated infrared emissivity of the filters. Knowledge of the emissivity will help instrument designers incorporate the filters into future experiments in planetary science, astrophysics, and cosmology.