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We improved the thermal dissociation cavity attenuated phase shift spectroscopy (TD-CAPS) instrument to measure atmospheric total peroxy nitrates (PNs) and organic nitrates (ONs) continuously under the condition of high NOx. In TD-CAPS, PNs and ONs are dissociated in heated quartz tubes to form NO2, and the NO2 concentration is measured by cavity attenuated phase shift spectroscopy (CAPS). The original TD-CAPS system overestimates PN and ON concentrations in the presence of high NO concentrations. Our laboratory experiments and numerical simulations showed that the main cause of the overestimation was NO oxidation to NO2 by peroxy radicals generated in the heated quartz tubes. In the improved system, NO was converted to NO2 by adding excess O3 after the quartz tubes so that CAPS detected NOx (NO and NO2) instead of NO2. The uncertainty of the improved system was less than 20% with ∼15 parts per billion by volume (ppbv) NO and ∼80 ppbv NO2. The estimated detection limit (3σ) was 0.018 ppbv with an integration time of 2 min in the presence of 64 ppbv NO2. The improved system was tested for measurement of PNs and ONs in an urban area, and the results indicated that interference from NO was successfully suppressed. [ABSTRACT FROM AUTHOR]

We present an experimental study on ac measurements at low frequencies (below 1 MHz) when the coaxial cables used for the measurement are resistive, as in cryogenic conditions. More precisely, we are interested in admittance or impedance measurements and the accurate determination of the phase. Our experiments were completed using an auto-balancing bridge impedance analyzer and various standard coaxial cables, as well as their serial combinations. We characterize the experimental setup, and then, we analyze and measure the phase shift introduced in impedance measurements by lead resistance. Using basic equations for electrical signal propagation in coaxial cables, we calculate phase shift in the whole frequency range and explain our data in the low frequency limit of our model. We propose a quantitative criterion to determine whether the experimental context is appropriate. If not, we show that by using an original calibration procedure, the imaginary part can be accurately recovered, avoiding artifacts. The calibration procedure can be applied to any ac voltage or current measurement, whatever the detection technique is, with known accuracy. [ABSTRACT FROM AUTHOR]

In an auto-balancing bridge for high impedance measurements, an operational amplifier (Op-Amp) is used to follow the intermediate potential. However, the input impedance of the Op-Amp introduces significant effects in high impedance measurements. This paper proposes a two-step excitation method (TSEM) and an incremental iterative method (IIM). The TSEM determines the magnitude of the Op-Amp input impedance and the initial value of the device under test. The IIM utilizes the TSEM results as initial conditions to quickly bring the bridge to equilibrium. To overcome the distortion issues associated with small amplitude excitation signals generated by the DAC under low resolution conditions, a programmable gain amplifier is designed. Additionally, a half-cycle difference algorithm is developed prior to the three-parameter sine fit to mitigate low-frequency direct-current drift caused by power frequency, thus improving measurement accuracy. Experimental results demonstrate that when the reference impedance is set to 1 MΩ, impedance measurements ranging from 1 kΩ to 100 MΩ can be achieved within the frequency range of 1 to 100 kHz. The precision evaluation reveals a relative standard deviation (RSD) of the modulus better than 0.384% and a standard deviation (SD) of the phase angle better than 3.49 mrad; especially for the impedance under test of 1 MΩ, the RSD is better than 0.006% and the SD is better than 0.1 mrad. [ABSTRACT FROM AUTHOR]

Particle shape is a significant feature of irregular particles. The interferometric particle imaging (IPI) technique has been introduced to retrieve submillimetric irregular rough particle shapes, while inevitable experimental noises hinder the convergence of two-dimensional (2D) particle shapes from single speckle patterns. In this work, a hybrid input–output algorithm with shrink-wrap support and oversampling smoothness constraints is utilized to suppress the Poisson noise in IPI measurement and recover accurate 2D shapes of particles. Our method is tested in numerical simulations on ice crystal shapes and actual IPI measurements on four different types of irregular, rough particles. The shape similarity of the reconstructed 2D shape has reached an average Jaccard Index score of 0.927, and the relative deviation of the reconstructed size is within 7% for all 60 tested irregular particles at the maximum shot noise level of 7.4%. Furthermore, our method has obviously reduced the uncertainty in the 3D shape reconstruction of irregular, rough particles. [ABSTRACT FROM AUTHOR]

Transverse profile monitors are essential devices to characterize particle beams in accelerators. Here, we present an improved design of beam profile monitors at SwissFEL that combines the use of high-quality filters and dynamic focusing. We reconstruct the profile monitor resolution in a gentle way by measuring the electron beam size for different energies. The results show a significant improvement of the new design compared to the previous version, from 20 to 14 µm. [ABSTRACT FROM AUTHOR]

In this paper, a robust composite control strategy in the framework of unified infinite-dimensional H ∞ optimal control is developed to support nano-scale periodic tracking with improved non-harmonic disturbance attenuation of piezo-actuated nano-stages with sensor-induced measurement delays. In particular, we analyze the electromechanical coupled dynamics and derive a multi-perturbation model, where an extended Youla–Kucera parameterization-based repetitive controller with a disturbance observer is constructed to optimize control performances on high-precision tracking and perturbation rejection. The controller parameters are solved by using a unified infinite-dimensional H ∞ optimization method. Comprehensive experiments on a piezo-actuated stage are conducted, where comparative results with representative methods, such as the conventional repetitive control and proportional-integral-derivative control, demonstrate significant performance improvements in hysteresis compensation, trajectory tracking, and disturbance suppression of the proposed method. [ABSTRACT FROM AUTHOR]

Improving the optical performance and functions of mirrors and lenses requires manufacturing pattern shapes such as those of microlens arrays. In this context, various measuring devices have been developed to accurately measure the depth of shapes with a microscopic interferometer. However, with an interferometer, the number of pixels of a light-receiving element, such as a charge-coupled device, is limited; furthermore, when measuring a pattern shape, the measurement field of view becomes narrow. Thus, measuring a wide range of shapes is not possible. By contrast, if the device can arbitrarily increase the number of measurement points, such as in the case of a three-dimensional measuring machine, in principle, a pattern shape can be measured, while ensuring the measurement capability for a wide range of shapes; however, in this case, the measurement time increases. A nano-profiler previously developed by the authors can measure the shape and slope angle distribution of a surface with a laser beam. In this study, the measurement program was changed to realize continuous high-speed scanning at 1 kHz, and the number of measurement points was increased to verify the compatibility between fine pattern shape measurements and diverse shape measurements. The results measured by the nano-profiler were compared with those obtained using microscopic and Fizeau-type interferometers, which can measure the pattern and overall shapes, respectively. In comparison, the difference in pattern depth and overall shape was 2.1 and 2.9 nm PV, respectively. [ABSTRACT FROM AUTHOR]

Triaxial compression experiments are commonly used to characterize the elastic and inelastic behavior of geomaterials. In situ measurements of grain kinematics, particle breakage, stresses, and other microscopic phenomena have seldom been made during such experiments, particularly at high pressures relevant to many geologic and man-made processes, limiting our fundamental understanding. To address this issue, we developed a new triaxial compression device called HP-TACO (High-Pressure TriAxial COmpression Apparatus). HP-TACO is a miniaturized, conventional triaxial compression apparatus permitting confining pressures up to 50 MPa and deviatoric straining of materials, while also allowing in situ x-ray measurements of grain-scale kinematics and stresses. Here, we present the design of and first results from HP-TACO during its use in laboratory and synchrotron settings to study grain-scale kinematics and stresses in triaxially compressed sands subjected to 15 and 30 MPa confining pressures. The data highlight the unique capabilities of HP-TACO for studying the high-pressure mechanics of sands, providing new insight into micromechanical processes occurring during geologic and man-made processes. [ABSTRACT FROM AUTHOR]

Numerical aperture (NA) of objective lens is an important parameter for the design of microscope systems and evaluation of imaging characteristics. The present mini review presents and summarizes the methods and instruments used in the NA measurement of objective lens. Five different categories of methods are introduced, which are original versions of apertometer measurement for angular aperture, method based on the working of Abbe apertometer and its modified versions, geometry-based methods, focal-plane (FP)-imaging-based methods, and back-FP-imaging-based methods, respectively. The methodology, devices, applied scenarios, and characteristics of methods (instruments) are summarized. Finally, some issues and potential areas of application are indicated as well. [ABSTRACT FROM AUTHOR]

We describe a digital microwave platform called Presto, designed for measurement and control of multiple quantum bits (qubits) and based on the third-generation radio-frequency system on a chip. Presto uses direct digital synthesis to create signals up to 9 GHz on 16 synchronous output ports, while synchronously analyzing responses on 16 input ports. Presto has 16 DC-bias outputs, four inputs and four outputs for digital triggers or markers, and two continuous-wave outputs for synthesizing frequencies up to 15 GHz. Scaling to a large number of qubits is enabled through deterministic synchronization of multiple Presto units. A Python application programming interface configures a firmware for synthesis and analysis of pulses, coordinated by an event sequencer. The analysis integrates template matching (matched filtering) and low-latency (184–254 ns) feedback to enable a wide range of multi-qubit experiments. We demonstrate Presto's capabilities with experiments on a sample consisting of two superconducting qubits connected via a flux-tunable coupler. We show single-shot readout and active reset of a single qubit; randomized benchmarking of single-qubit gates showing 99.972% fidelity, limited by the coherence time of the qubit; and calibration of a two-qubit iSWAP gate. [ABSTRACT FROM AUTHOR]

We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute, which features an interior cubic volume with each side of length 2.92 m, thus providing an accessible space of 25 m3. The MSR has 87 openings of diameter up to 220 mm for operating the experimental apparatus inside and an intermediate space between the layers for housing sensitive signal processing electronics. The characterization measurements show a remanent magnetic field in the central 1 m3 below 100 pT and a field below 600 pT in the entire inner volume, up to 4 cm to the walls. The quasi-static shielding factor at 0.01 Hz measured with a sinusoidal 2 μT peak-to-peak signal is about 100 000 in all three spatial directions and increases rapidly with frequency to reach 108 above 1 Hz. [ABSTRACT FROM AUTHOR]

This paper describes a new experimental setup designed for the direct measurement of the Rayleigh ratio and Rayleigh scattering length for linear alkylbenzene, a solvent commonly used in liquid scintillator detectors for neutrino experiments. Using the new approach, the perpendicularly polarized Rayleigh ratio was determined to be (4.52 ± 0.28) × 10−6 m−1 sr−1 at 405 nm and (3.82 ± 0.24) × 10−6 m−1 sr−1 at 432 nm, and the corresponding Rayleigh scattering length was LRay = 22.9 ± 0.3(stat.) ± 1.7(sys.) m at 405 nm and LRay = 27.0 ± 0.9(stat.) ± 1.8(sys.) m at 432 nm. These results are consistent with both previous results determined using other experimental strategies and theoretical predictions. [ABSTRACT FROM AUTHOR]

Alternating acquisition of background and sample spectra is often employed in conventional Fourier-transform infrared spectroscopy or ultraviolet–visible spectroscopy for accurate background subtraction. For example, for solvent background correction, typically a spectrum of a cuvette with solvent is measured and subtracted from a spectrum of a cuvette with solvent and solute. Ultrafast spectroscopies, though, come with many peculiarities that make the collection of well-matched, subtractable background and sample spectra challenging. Here, we present a demountable split-sample cell in combination with a modified Lissajous scanner to overcome these challenges. It allows for quasi-simultaneous measurements of background and sample spectra, mitigating the effects of drifts of the setup and maintaining the beam and sample geometry when swapping between background and sample measurements. The cell is moving between subsequent laser shots to refresh the excited sample volume. With less than 45 μl of solution for 150 μm optical thickness, sample usage is economical. Cell assembly is a key step and covered in an illustrated protocol. [ABSTRACT FROM AUTHOR]

Ion sources produce beams used in accelerators and other applications. Both development and use of ion sources need beam diagnostics to probe the plasma processes and beam formation for optimization purposes and to produce beam parameters needed for transport tuning. These diagnostics include beam intensity measurements usually carried out with Faraday cups or inductive pickups, magnetic separation, profile measurements with scintillation screens and wires, and phase space measurements with different types of emittance scanners. [ABSTRACT FROM AUTHOR]

The conventional two-tone test method cannot measure the amplitude and phase of IM3 products under different operating conditions. The nonlinearity and memory effects of mixers under different operating conditions have not been characterized in existing research. This paper presents a new two-tone measurement method for characterizing the nonlinearity and memory effects of mixers under the excitation of large carrier signals of different amplitudes. This new test method differs from the conventional two-tone test in that the two-tone test signal is superimposed on a large carrier signal. The role of the large carrier signal is to excite mixers into different operating conditions. The amplitude and phase of the IM3 product of the mixer could be measured to characterize the nonlinearity and memory effects under different operating conditions using this method. This novel method is based on a vector network analyzer (VNA) and signal generator (SG). Compared with the conventional method of only using a spectrum analyzer and SG, the VNA can remove the system error through a calibration algorithm to ensure the accuracy of the IM3 product measurement results. The measurement results, for the first time, demonstrated the nonlinearity and memory effects of mixers in different amplitude regions of a large carrier signal. These findings are advantageous and can facilitate further research to simplify the digital pre-distortion model of mixers under different operating conditions. [ABSTRACT FROM AUTHOR]

An experimental technique is developed to simultaneously measure both temporal and spatial coherences of a light source by altering a standard Michelson interferometer, which has been primarily used for measuring temporal coherence only. Instead of using simple plane mirrors, two retroreflectors and their longitudinal and lateral movements are utilized to incorporate spatial coherence measurement using this modified Michelson interferometer. In general, one uses Young's double slit interferometer to measure spatial coherence. However, this modified interferometer can be used as an optical setup kept at room temperature outside a cryostat to measure the spatiotemporal coherence of a light source placed at cryogenic temperatures. This avoids the added complexities of modulation of interference fringe patterns due to single slit diffraction as well. The process of mixing of spatial and temporal parts of coherences is intrinsic to existing methods for dual measurements. We addressed these issues of spatiotemporal mixing, and we introduced a method of "temporal filtering" in spatial coherence measurements. We also developed a "curve overlap" method that is used to extend the range of the experimental setup during temporal coherence measurements without compromising the precision. Together, these methods provide major advantages over plane mirror based standard interferometric systems for dual measurements in avoiding systematic errors, which lead to inaccuracies, especially for light sources with low coherences. [ABSTRACT FROM AUTHOR]

Laboratory experiments typically test opacity models by measuring spectrally resolved transmission of a sample using bright backlight radiation. A potential problem is that any unaccounted background signal contaminating the spectrum will artificially reduce the inferred opacity. Methods developed to measure background signals in opacity experiments at the Sandia Z facility are discussed. Preliminary measurements indicate that backgrounds are 9%–11% of the backlight signal at wavelengths less than 10 Å. Background is thus a relatively modest correction for all Z opacity data published to date. Future work will determine how important background is at longer wavelengths. [ABSTRACT FROM AUTHOR]

Several aspects contributing to the temporal broadening in the measurement of ultrafast fluorescence by means of up-conversion wave mixing are presented: the characteristics of the sample, those of the collection optics, and the wave mixing with the gate pulse in a non-linear crystal. It is concluded that these contributions are emission wavelength dependent and can be as important as the pulse durations in determining the instrument response function in this technique. [ABSTRACT FROM AUTHOR]

This article was originally published online on 8 March 2024 with Y. Mazuz-Harpaz's name misspelled. The author's name appears correct above. AIP Publishing apologizes for the error. All online versions of the article were corrected on 27 March 2024; the article is correct as it appears in the printed version of the journal.By N. Kliss; J. Wengrowicz; J. Papeer; Y. Mazuz-Harpaz; E. Porat; A. Zigler and Y. FrankReported by Author; Author; Author; Author; Author; Author; Author [Extracted from the article]

Collisional merging formation of field-reversed configuration (FRC) plasmas at supersonic velocities was performed using the FRC amplification via translation-collisional merging device. Supersonic collisional merging formation is a novel technique to form an FRC that is long-lived compared to a conventional initial formation FRC; however, this technique requires measuring the plasma parameters at multiple points simultaneously because of the dynamic translation/merging process. Herein, we have developed a new interferometer and have observed the dynamic behavior of FRCs in the formation, translation, and merging processes simultaneously. In this study, as one of the performance evaluations of the developed simultaneous density measurement, collision/merging of FRCs have been conducted in the confinement section with and without background neutral gas. Comparing translation into deuterium gas vs translation into a vacuum environment prior to the collisional merging, we found that the background neutral particles were trapped in the merged FRC; moreover, a difference in the decay rate of the stored internal energy was observed. [ABSTRACT FROM AUTHOR]

The C-2W experiment produces advanced beam-driven field reversed configuration (FRC) plasmas, which are sustained in steady state utilizing variable energy neutral beams (15–40 keV, total power up to 21 MW), advanced divertors, end bias electrodes, and an active plasma control system. Since heating, current drive, and refueling from neutral beam injection are essential to FRC sustainment, it is crucial to have accurate measurements of the beam power being injected into the plasma. A new tungsten wire calorimeter has been designed, built, calibrated on a test stand, and implemented to make the first direct measurements of the time-average injected beam power into C-2W. This paper outlines the design of the diagnostic, along with calibration methods and experimental results. [ABSTRACT FROM AUTHOR]

Seebeck measurement is a crucial step for characterizing thermoelectric samples, as measuring the accurate value with a simpler system design is challenging. Here, we report a simple design of the Seebeck coefficient measurement system, which can measure the thermo-emf (Seebeck coefficient) of the sample, under a limited temperature range of 300–600 K. Unlike the majority of the reported instrumental designs, the system does not have a hot walled chamber. The sample is sandwiched between two brass block supported heaters, which are controlled separately. Thus, this type of system is suitable for a window of the temperature range near room temperature. In this paper, we report the system that can measure the Seebeck coefficient up to 600 K. The heaters touch the sample through 1 mm thick silver caps, which offer insignificant thermal resistance and a stable temperature, as seen through experiment as well as COMSOL simulations. A typical sample has, at maximum, a diameter of 10 mm and a thickness of 2–3 mm. A reversible temperature gradient is applied in quasi-static direct current mode. By virtue of its design, the sample holder ensures a minimum thermal and electrical contact resistance during a measurement cycle. The combination of metals used for measurement (Ag and Cu) shows negligible junction contribution. The variance up to ±2% and accuracy up to 8% at a high temperature have been obtained using calibration sample reference data of state-of-the-art commercial systems. [ABSTRACT FROM AUTHOR]

A custom setup for Seebeck coefficient and electrical resistivity measurements of thin films as a function of temperature in the range of 10–300 K was developed. The Seebeck coefficient is measured using a two-probe arrangement and using either a dynamical or steady/quasi-steady differential method. The temperature differences (ΔTs) for these measurements across the samples are achieved by using resistive heaters embedded in two copper blocks. The sample is screwed to these blocks and is in pressured contact with the measurement probes. The electrical resistivity is measured with a two-probe arrangement. To verify the reliability of the developed setup, measurement tests were performed on commercial niobium foil and a specular spin valve previously studied, having obtained a great accordance (within ∼3%) between this setup's experimental results and the reference measurements. [ABSTRACT FROM AUTHOR]

A 90 GHz W-band millimeter-wave back-scattering system is designed and installed for measuring electron scale turbulence (k⊥ρs ∼ 40). A metal lens relay antenna is used for in-vessel beam focusing, and a beam diameter of less than 40 mm is achieved in the plasma core region. This antenna can be steered at an angle of 159° ± 6°, which almost covers the plasma radius. The estimated size of the scattering volume is ∼105 mm at the edge and 135 mm at the core, respectively. A 60 m corrugated waveguide is used to achieve a low transmission loss of ∼8 dB. A heterodyne detection system for millimeter-wave circuits with probing power modulation can distinguish the scattered signal from background noise. [ABSTRACT FROM AUTHOR]

In this paper, an open-loop self-oscillating fluxgate-based current measurement method is presented. The proposed sensor does not require the low-pass filter necessary in traditional measurement technologies and does not require an analog-to-digital converter when connected to digital systems. More importantly, although the proposed measurement method is based on the open-loop configuration, its measurement accuracy is close to that of the traditional self-oscillating fluxgate measurement technology based on the closed-loop configuration. Accurate mathematical models are established to describe the basic characteristics of the measurement method, and design criteria of the sensor are proposed. The test results show that the proposed measurement method has good linearity; for example, in the full scale of 100 A, its linearity is about 0.4% and can be improved to below 0.2% when the first-order polynomial fitting method is used. [ABSTRACT FROM AUTHOR]

In our previous paper [M. Rępalska et al., Rev. Sci. Instrum. 90, 024103 (2019)], a new method for measuring the growth of children based on the measurement of the lower leg length during foot movement was described. This current paper presents more measurements being conducted to ensure the effectiveness of the proposed arrangement. The study was carried out at weekly intervals with a research group amounting to 20 participants. The presented results show that the method allows for the identification of even a weekly increase in the lower leg length at different velocities of growth. In addition, the method enables the estimation of the trend characterizing each individual and can distinguish the periods of time during which perturbative factors in the process of growth may arise. A metrological analysis was also conducted, allowing a qualitative evaluation of the results, which are presented together with the measurement uncertainties. [ABSTRACT FROM AUTHOR]

We present in this paper a new design of a capacitive calibration kit for scanning microwave microscopy (SMM). As demonstrated by finite element modelings, the produced devices are highly independent of material parameters due to their lateral configuration. The fabrication of these gold-based structures is realized by using well established clean-room techniques. SMM measurements are performed under different conditions, and all capacitive structures exhibit a strong contrast with respect to the non-capacitive background. The obtained experimental data are employed to calibrate the used SMM tips and to extract the capacitance of produced devices following a method based on the short-open-load calibration algorithm for one-port vector network analyzers. The comparison of experimental capacitance and nominal values provided by our models proves the applicability of the used calibration approach for a wide frequency range. [ABSTRACT FROM AUTHOR]

A dual trace intra-pulse and inter-pulse spatio-spectral interferometer has been set up to study the temporal stability of a ∼200 fs duration laser pulse train from a cw mode-locked laser oscillator. Simultaneous recording of twin interferograms helps identify the phase error in inter-pulse interferograms due to the diagnostic setup kept in a standard laboratory environment. Applicability of inter-pulse tilted pulse-front interferograms has been demonstrated to constitute an alternative inexpensive method for visual detection and estimation of phase slippage and pulse repetition frequency of an ultra short pulse train. The effect of pump beam intensity on the repetition rate of pulses due to accumulated intra-cavity non-linear phase shifts is also presented. [ABSTRACT FROM AUTHOR]

One of the most versatile techniques to study thermal transport in low dimensional materials utilizes a suspended micro-island device integrated with resistance thermometers. Advancements in experimental techniques with suspended micro-island devices resulted in increasing capabilities such as enhancing temperature resolution and expanding a measurable range of sample thermal conductance. In this work, we further improve the suspended micro-island based technique. Specifically, we present a rigid structure of the suspended micro-island device and robust measurement method for sequential heating. The rigid structure enabled by T-shaped beams prevents the displacement of suspended micro-islands, thus increasing the success rates of sample transfer especially for samples with a large cross-sectional area and short length. Besides, thermal isolation of micro-islands is maintained at a similar level through the T-shaped beams compared to conventional flat beams. Next, we introduce an advanced experimental approach that enables sequential heating to measure sample thermal conductance. Sequential heating in micro-islands can be used either to measure accurate sample thermal conductance even under unexpected asymmetric supporting beam configuration or to study thermal transport dependence on heat flow directions. Using a switch matrix for sequential heating eliminates the need for experimental reconfigurations during the experiment. We demonstrate the experimental method with thermal conductivity measurements of the Si nanowire under both the ideal symmetric beam configuration and replicated asymmetric beam configuration scenarios. The results show that the developed experimental method effectively eliminates potential experimental errors that can arise from the asymmetry in beam configurations. [ABSTRACT FROM AUTHOR]

Measurement for modeling of the high-power transistors is difficult due to its high-power and low-impedance characteristics. In this paper, novel methods and devices were designed and applied to achieve precise measurements of the high-power transistors. Fixtures capable of withstanding high voltage and current were designed to replace traditional radio frequency (RF) probes for higher power capacity. To reduce the impact of capacitive and inductive components of traditional bias tees on the rising/falling edge, two wideband 90° hybrid couplers that were connected back-to-back were designed for pulsed measurements. The measurement system of stable S-parameters with the Vector Network Analyzer (VNA) was reported, which could protect the devices and laboratory equipment from damage of self-oscillation. Application of several innovative approaches enabled accurate I–V characteristic and S-parameters measurements of high-power transistors in DC or pulsed mode. Experimental results of a 30 W gallium nitride high-electron-mobility transistor verified the validity. [ABSTRACT FROM AUTHOR]

In this paper, a novel method of film thickness measurement based on weak measurements is proposed by analyzing the quantitative relationship between film thickness and the weak measurement amplified shift of the photonic spin Hall effect, and the corresponding measurement system is established to verify it through experiments. This method can measure the thickness of an arbitrary dielectric film with nanometer resolution. The theoretical analysis and experimental results show that the method is reasonable, feasible, and reliable, and the structure of the measurement system is simple, easy to operate, and easy to assemble into a prototype instrument. The measurement model and method provide not only a new way for the measurement of thin film thickness but also an important reference for the precise measurement of other optical interface parameters. [ABSTRACT FROM AUTHOR]

Existing approaches for the field measurements of the frequency-dependent soil properties take a significant amount of time, making it difficult to obtain new experimental data and study the electrical soil properties further. However, a relatively uncomplicated measurement device assembled from accessible electronic components can make the measurements almost as easy as those for the regular low-frequency resistivity. This article presents a detailed description of such a device: the description includes the functional scheme, pseudocodes for central parts of the calculation algorithm, used electronic components, and working principle of the device. This article discusses the reasons behind the chosen parameters of the device (such as isolation between the measurement circuits, generated signal waveform, and usage of the electrode arrays) and addresses other possible approaches for the measurements. This paper also provides several measurement results and a comparison with a calculation result for a particular electrode array configuration. Finally, this work describes essential aspects affecting the accuracy of measurement results. [ABSTRACT FROM AUTHOR]

This manuscript describes the development and operation of an apparatus for the measurement of steady-state and transient gas permeation through different types of solid materials with varying geometries. It is capable of operation from 293 K to 673 K and could theoretically be used with any non-corrosive gas or a mix of gases, although only hydrogen isotopes are used in the current study. A quadrupole mass spectrometer is used to measure permeation fluxes as low as 1011 molecules/s. This unique test setup allows for the simultaneous measurement of diffusivity, solubility, and permeability. Furthermore, varying the pressure in the fore-sample volume allows for tests of Sievert's law and can give information on surface effects. [ABSTRACT FROM AUTHOR]

A quartz pendulum, gold plated on both sides, is the core component of a quartz accelerometer. Currently, a two-wire manual measurement method is employed to measure the resistance at 24 key positions on the gold plating to evaluate manufacturing quality. This method is time-consuming and has poor repeatability. In this paper, an automatic measurement system is proposed to measure these 24 resistances. The proposed system consists primarily of a lab-designed holder that clamps the sample, a machine vision unit to measure the sample position, RXY-stages for precise positioning, two lab-designed probes with 48 needles to sense the electrical signals, a multichannel self-switching module to sample the electrical signals from the probe needles, and a 7½-digital multimeter to measure the resistances. In addition, a simple, precise pre-measurement positioning method is introduced here. Experimental results show that the quartz-pendulum resistances can be measured quickly and precisely using the proposed system. The measurement rate of 1 pendulum/min is a factor of 10 faster than the current manual method, the measurement stability error is only 0.9 mΩ (a relative error of 0.13%), and the measurement repeatability error is 1.2 mΩ (a relative error of 0.20%). [ABSTRACT FROM AUTHOR]

We present a comprehensive study of the frequency-dependent sensitivity for measurements of the AC elastocaloric effect by applying both exactly soluble models and numerical methods to the oscillating heat flow problem. These models reproduce the finer details of the thermal transfer functions observed in experiments, considering here representative data for single-crystal Ba(Fe1−xCox)2As2. Based on our results, we propose a set of practical guidelines for experimentalists using this technique. This work establishes a baseline against which the frequency response of the AC elastocaloric technique can be compared and provides intuitive explanations of the detailed structure observed in experiments. [ABSTRACT FROM AUTHOR]

Transverse 2D phase space distributions of a 2.1 MeV, 5 mA H− beam are measured at the Proton Improvement Plan II Injector Test accelerator at Fermilab with an Allison scanner. This paper describes the design, calibration, and performance of the scanner along with the main results from beam measurements. Analyses of the recorded phase portraits are performed primarily in action-phase coordinates. The stability of the action under linear optics makes it easier to compare measurements taken under different beamline conditions. The amplitude of a single measured point ("pixel") is proportional to the phase density in the corresponding portion of the beam. When the Twiss parameters are calculated using only the high-phase density part of the beam, the pixel amplitude in the beam core is found to be decreasing approximately exponentially with action and to be phase-independent. Outside of the core, the amplitudes decrease with action at a slower rate than in the core. This "tail" comprises 10%–30% of the beam, with 0.1% of the total measured intensity extending beyond action 10–20 times larger than the rms emittance. The transition from the core to the tail is accompanied by the appearance of two "branches" that are separated in phase and extend beyond the core. A set of selected measurements shows that there is no measurable emittance dilution along the beamline; the beam parameters are practically constant over a 0.5 ms pulse; and scraping in various parts of the beamline is an effective way to decrease the transverse tails by removing the branches. [ABSTRACT FROM AUTHOR]

The inaccurate deflection behavior of the probing system degrades the performance of the diameter-measuring machines. In this experiment, the probing is improved, applying an autocollimator and an angular positioning datum. We have devised this datum using a liquid wedge. A ring gauge is chosen as a workpiece to evaluate the deflection behavior of the probing system. The improved uncertainty of the probing is found as low as 40 nm. Subsequently, the inner diameter of the ring gauge is measured on this experimental setup. By employing a simulation, we aligned the workpiece. The deflections of the stylus are optimized to achieve zero deflection error at the zenith points. Consequently, the swing of the probe at the zenith points is combined with the rectilinear displacement of the workpiece to estimate the inner diameter. The uncertainty of the measurement of the ring gauge is improved up to 140 nm. [ABSTRACT FROM AUTHOR]

Fringe projection profilometry has been proverbially utilized for measuring the shapes of objects. A common challenge in those systems is to accurately obtain a smooth absolute phase. Many new methods have been proposed to address this challenge. In this paper, we discuss a technique based on variant shifting phases. This approach embeds codewords into the shifting phase and only needs four patterns. However, reliable measurement results are difficult to achieve with a large number of codewords because of the phase errors. To address this shortcoming, we present a robust coding method that embeds a specific code sequence into the shifting phase and can generate more than 36 periods. The fringe order is determined using unique three-adjacent-codes combining the current period and its neighbors. An error correction algorithm is also proposed to optimize the codewords. The proposed method is experimentally verified using an established measurement system. The result shows that the proposed method is robust and efficient. [ABSTRACT FROM AUTHOR]

Recent studies have shown that head movements associated with cardiac activity contain a heart rate (HR) signal. In most previous studies, subjects were required to remain stationary in a specific environment during HR measurements, and measurement accuracy depended on the choice of target in the scene, i.e., the specified region of the face. In this paper, we proposed a robust HR measurement method based on ballistocardiogram (BCG) technology. This method requires only a camera and does not require that users establish a complex measurement environment. In addition, a bidirectional optical flow algorithm is designed to select and track valid feature points in the video captured by using the camera. Experiments with 11 subjects show that the HR values measured using the proposed method differ slightly from the reference values, and the average error is only 1.09%. Overall, this method can improve the accuracy of BCG without limitations related to skin tone, illumination, the state of the subject, or the test location. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) materials are fine ceramics with non-linear electrical properties. Their non-linear electrical properties appear from a double Schottky barrier formed in the grain boundaries (GBs). These microparticles are not easy to measure directly with electrical microprobes due to their small size (i.e., 50–100 µm). We developed a direct measurement process with two Cu cables of small diameter. In this paper, we have developed an amplified method of the previous measurement system, which can measure not only one ZnO microvaristor directly but also a group of microvaristors in a series connection. The I–V characteristics of the microvaristors were measured with the modified method, and we found non-linear properties in each particle while measuring I–V characteristics. Their fine structures were also investigated, and the non-linear I–V characteristics showed a direct relationship with the number of the GBs of the samples. Moreover, varistor voltage was calculated for a single GB for the I–V measurements for ZnO microvaristors connected in a series connection. [ABSTRACT FROM AUTHOR]

A simple method for measuring electrical resistivity under destructive pulsed magnetic fields is presented. This method uses pick-up voltage as the power source to allow the measurement of the absolute value of resistivity in ultra-high magnetic fields above 100 T. The experimental setup and its operation are described in detail, and its performance is demonstrated using critical field measurements of thin-film FeSe0.5Te0.5 samples. Possible scientific applications of this setup in high magnetic fields as well as in any other environment with a high field sweep rate are also discussed. [ABSTRACT FROM AUTHOR]

This article presents a concept and implementation of a calibrated streaked spectral pyrometer (SSP) temperature diagnostic used in dynamically driven shock experiments on a two-stage gas gun. This system relies upon measuring the total system response using a tunable monochromator, a NIST-traceable calibrated power meter, and a SSP. The diagnostic performance is validated against previously measured temperatures of shock driven z-cut quartz at 99 GPa and 93 GPa. The results are found to agree with the literature to within 5% and are discussed in this manuscript. The experimental setup utilizes measurements from multiple SSP systems per sample, providing several independent measurements and substantially increasing confidence in the extrapolated shock driven sample temperature. [ABSTRACT FROM AUTHOR]

A dual beam magneto-optical setup employing a dual axis photoelastic modulator (PEM) and an intensity-stabilized laser was designed and constructed. The beam transmitted through or reflected of the sample is split by a Wollaston prism into two orthogonal high-quality linearly polarized beams. Two photodetectors are used to measure the DC and 2ω components of each beam's intensity. Theoretical calculations using Jones matrices show that the difference between the 2ω signals, i.e., ΔI2ω, is linearly proportional to the Kerr or Faraday rotation of the sample. Different from I2ω of a traditional single beam setup, the ΔI2ω does not contain an offset caused by the Fabry Perot interference in the PEM's optical head, making the setup less sensitive for small sample movements and laser drifts including intensity, wavelength, and beam direction drifts all originating from mainly temperature fluctuations in the lab. [ABSTRACT FROM AUTHOR]

This document is an erratum for an article titled "Methods and instruments for the measurement of numerical aperture for microscope objective lens: A mini review" published in the Review of Scientific Instruments. The erratum states that a reference to the author's master's thesis was mistakenly omitted from the original article and provides the correct locations where the reference should be added. The author apologizes for the oversight but assures readers that these changes do not impact the conclusions of the paper. The document also includes author declarations regarding the contributions made to the article. [Extracted from the article]

Beam momentum spread is a key parameter of the linac injector at the Xi'an Proton Application Facility (XiPAF), China. A momentum spread measurement method using multiple beam position monitors (BPM) was successfully developed recently at Tsinghua University, China. This work is an extension of the method. The original method requires at least three BPMs to perform the measurement, and the BPMs should be installed far from the accelerator exit, causing long measurement space and low BPM signals. The new method only needs two BPMs, and a much shorter measurement space is proposed for the low-current linac in this paper. The new method was successfully tested at XiPAF. The measured rms momentum spread at the Radio Frequency Quadrupole exit is (5.05 ± 0.06) × 10−3, which agrees well with the spectrometer measured value (5.09 ± 0.05) × 10−3. [ABSTRACT FROM AUTHOR]

Combined frequency-resolved techniques are suitable to study electrochromic (EC) materials. We present an experimental setup for simultaneous electrochemical and color impedance studies of EC systems in transmission mode and estimate its frequency-dependent uncertainty by measuring the background noise. We define the frequency-dependent variables that are relevant to the combined measurement scheme, and a special emphasis is given to the complex optical capacitance and the complex differential coloration efficiency, which provide the relation between the electrical and optical responses. Results of a test measurement on amorphous WO3 with LED light sources of peak wavelengths of 470, 530, and 810 nm are shown and discussed. In this case, the amplitude of the complex differential coloration efficiency presented a monotonous increase down to about 0.3 Hz and was close to a constant value for lower frequencies. We study the effect of the excitation voltage amplitude on the linearity of the electrical and optical responses for the case of amorphous WO3 at 2.6 V vs Li/Li+, where a trade-off should be made between the signal-to-noise ratio (SNR) of the optical signal and the linearity of the system. For the studied case, it was possible to increase the upper accessible frequency of the combined techniques (defined in this work as the upper threshold of the frequency region for which the SNR of the optical signal is greater than 5) from 11.2 Hz to 125.9 Hz while remaining in the linear regime with a tolerance of less than 5%. [ABSTRACT FROM AUTHOR]

A new method for measuring the growth of children is presented, based on the measurement of the lower leg length during foot movement. This is a touch measurement, but the obtained characteristic of the measured lower leg length, as a function of the pressure force, is reduced to a non-contact measurement. A setup prototype is built and preliminary research conducted. Based on the results obtained, it is concluded that the method allows the observation of increases in child lower leg length at frequent intervals (e.g., weekly). The developed measurement method has a high accuracy, and the results allow for differentiation between periods of child good health and indisposition. [ABSTRACT FROM AUTHOR]

This paper presents a flexure-based compliant mechanism for testing accelerometer transverse sensitivity. The definition of transverse sensitivity is first described. Subsequently, the detailed structure of the developed mechanism is introduced. The principle of this method and the corresponding theoretical model are analyzed. Based on the principle, a prototype is manufactured and an experimental platform is set up. The circular trajectory tests are carried out to verify the feasibility of this method. It shows that the precision of the circular trajectory can be guaranteed. Finally, a three-axis piezoelectric accelerometer is tested. The maximum transverse sensitivity is below 5%, and its maximum measurement uncertainty is 0.15%, while the maximum measurement uncertainty of the corresponding direction angle is 0.79°. It demonstrates that the proposed method is reasonable and accurate. [ABSTRACT FROM AUTHOR]

In order to improve the measuring accuracy of micro-electromechanical system (MEMS) resonant sensor with micro-cantilever structure to measure fluid density, a temperature compensation method is presented. The elastic modulus of the micro-cantilever is calculated considering its temperature coefficient so that the working equation to measure fluid density is obtained with decreasing temperature disturbance on the measuring accuracy. The simulations and experimental measurements of several fluids with different densities were carried out by the MEMS micro-cantilever resonant sensor under different temperatures. The simulation analyses showed that the fluid densities measured by using the proposed resonant density sensor with temperature compensation were more fitted with the reference density values than those without temperature compensation. The experimental results showed that both the measuring accuracy and stability of the MEMS micro-cantilever resonant sensor in fluid density measurement were increased more than twice based on the temperature compensation method. Therefore, the proposed temperature compensation method is important to improve the measuring precision and stability of the MEMS micro-cantilever resonant sensor in fluid density detection fields. [ABSTRACT FROM AUTHOR]

We propose herein a simple and reliable technique to directly measure in real time the loop gain and bandwidth of a phase-locked loop (PLL). This technique can be used to make direct real-time measurements of the closed-loop gain of a PLL without breaking the locking state. We show the validity of the technique by demonstrating that the theoretical analysis is consistent to the experimental results with an actual PLL system. This simple technique with a systematic experimental configuration may easily be extended to the other PLL systems that require precise loop gain and bandwidth measurements. [ABSTRACT FROM AUTHOR]