Improve Measurement Accuracy Research Articles

In‐Device Ballistic‐Electron‐Emission Spectroscopy for Accurately In Situ Mapping Energy Level Alignment at Metal–Organic Semiconductors Interface

AbstractEnergy level alignment at metal/organic semiconductors (OSCs) interface governs electronic processes in organic electronics devices, making its precise determination essential for understanding carrier transport behaviors and optimizing device performance. However, it is proven that accurately characterizing the energy barrier at metal/OSC interface under operational conditions remains challenging due to the technical limitations of traditional methods. Herein, through integrating highly‐improved device constructions with an ingenious derivative‐assisted data processing method, this study demonstrates an in‐device ballistic‐electron‐emission spectroscopy using hot‐electron transistors to accurately characterize the energy barrier at metal/OSC interface under in‐operando conditions. This technique is found that a remarkable improvement in measurement accuracy, reaching up to ±0.03 eV, can be achieved—surpassing previous techniques (±0.1–0.2 eV). The high accuracy allows us to monitor subtle changes in energy barriers at metal/OSC interface caused by variations in the aggregation state of OSCs, a phenomenon that is theoretically possible but failed to be directly demonstrated through conventional methods. Moreover, this study makes demonstration that this technology is universally applicable to various metal/OSC interfaces consisting of electron‐transporting, hole‐transporting, and ambipolar OSCs. These findings manifest the great potential of this method to advance both theoretical exploration and technical applications in organic electronics.

Drift compensation system of an autocollimator based on reciprocal roll angles and a feedback combination target

To address the issues of limited field of view and beam drift in traditional autocollimation measurements, a novel, to our knowledge, autocollimation measurement method is proposed. This method is based on the principle of full-circle continuous measurement using reciprocal roll angles of a compound biaxial system, combined with a feedback and compensation mechanism for beam drift using both calibration and compensation targets. A self-collimating small-angle measurement system model, coupled with a compound biaxial turntable and combined target, is established using ray tracing and perspective projection transformation techniques. Additionally, a closed-loop beam drift compensation system is developed by applying a BP neural network and a PID control algorithm. Experimental tests on the compensation system demonstrate a significant improvement in measurement accuracy and stability. The results show that this method satisfies the requirements for small-angle autocollimation measurement, and the method also enhances the overall stability of the autocollimation system.

Experiment and Prediction of Enhanced Gas Storage Capacity in Depleted Gas Reservoirs for Clean Energy Applications

Utilizing depleted gas reservoirs for gas storage is the most efficient method. However, the impact of multi-cycle injection-production and water invasion on rock properties and gas-water seepage dynamics remains unclear. This study investigates such reservoirs' multi-cycle stress sensitivity and gas-water displacement behavior. Results show that multi-cycle injection-production and water invasion increase the stress sensitivity of the gas and damage gas storage space and seepage channels. This study also proposed a new unsteady gas-water relative permeability testing method and a prediction model based on in-situ X-ray CT scanning, improving measurement accuracy by 30%. The results found that the gas's relative permeability is directly proportional to the injection rate and inversely proportional to the initial gas saturation. A gas-water relative permeability model was established, demonstrating that gas-water interference intensifies as the number of cycles increases. In a gas-water transition zone in depleted gas reservoirs, gas relative permeability damage reaches 81%, reducing the movable pore space and impacting injection-production rates and capacity. This study offers valuable recommendations for optimizing production and dynamic prediction in depleted gas reservoirs, contributing to clean energy applications.

Scene Measurement Method Based on Fusion of Image Sequence and Improved LiDAR SLAM

To address the issue that sparse point cloud maps constructed by SLAM cannot provide detailed information about measured objects, and image sequence-based measurement methods have problems with large data volume and cumulative errors, this paper proposes a scene measurement method that integrates image sequences with an improved LiDAR SLAM. By introducing plane features, the positioning accuracy of LiDAR SLAM is enhanced, and real-time odometry poses are generated. Simultaneously, the system captures image sequences of the measured object using synchronized cameras, and NeRF is used for 3D reconstruction. Time synchronization and data registration between the LiDAR and camera data frames with identical timestamps are achieved. Finally, the least squares method and ICP algorithm are employed to compute the scale factor s and transformation matrices R and t between different point clouds from LiDAR and NeRF reconstruction. Then, the precise measurement of the objects could be implemented. Experimental results demonstrate that this method significantly improves measurement accuracy, with an average error within 10 mm and 1°, providing a robust and reliable solution for scene measurement.

Research on the Detection Principle of Coal Ash by X-Ray Transmission Based on FLUKA

This study addresses the timely and accurate measurement of coal ash content by proposing a detection model based on nuclear science technology, which is validated using FLUKA 4-4.0 simulation software. The background provided highlights the fact that coal ash content is a critical sales indicator, and its precise measurement is essential for adjusting production parameters in coal preparation plants. In terms of methodology, this study employs the widely used FLUKA4-4.0 software in the field of nuclear physics to simulate X-ray transmission through coal, investigating the impact of changes in coal type on the accuracy of ash measurements. The results indicate that, when the proportions of high-atomic-number elements in coal remain constant, the ash measurement results are accurate and reliable. However, significant fluctuations occur when these proportions change. The conclusion emphasizes the fact that variations in coal type are the primary cause of inaccuracies in ash measurement, particularly when the ratios of high-atomic-number elements are altered. This research provides a new perspective on the online measurement of coal ash content and offers theoretical support for improving measurement accuracy.

Identifying Potential Landslides in Low-Coherence Areas Using SBAS-InSAR: A Case Study of Ninghai County, China

The southeastern coastal regions of China are characterized by typical hilly terrain with abundant rainfall throughout the year, leading to frequent geological hazards. To investigate the measurement accuracy of surface deformation and the effectiveness of error correction methods using the small baselines subset–interferometry synthetic aperture radar (SBAS-InSAR) method in identifying potential geological hazards in such areas, this study processes and analyzes 129 SAR images covering Ninghai County, China. By processing coherence coefficients using the Stacking technique, errors introduced by low-coherence images during phase unwrapping are mitigated. Subsequently, interferograms with high coherence are selected for time-series deformation analysis based on the statistical parameters of coherence coefficients. The results indicate that, after mitigating errors from low-coherence images, applying the SBAS-InSAR method to only high-coherence SAR datasets provides reliable surface deformation results. Additionally, when combined with field geological survey data, this method successfully identified landslide boundaries and potential landslides not accurately detected in previous geological surveys. This study demonstrates that using the SBAS-InSAR method and selecting high-coherence SAR images based on interferogram coherence statistical parameters significantly improves measurement accuracy and effectively identifies potential geological hazards.

Optimizing Ship Draft Observation with Wave Energy Attenuation and PaddlePaddle-OCR in an Anti-Fluctuation Device

With the development and application of artificial intelligence (AI) in the shipping industry, using AI to replace traditional draft survey methods in bulk carriers can significantly reduce manpower, lower the risks associated with visual observations, improve measurement accuracy, and minimize the impact of human subjective factors. Ultimately, the integration of software and hardware technologies will replace human visual observations with automated draft measurement calculations. A similar anti-fluctuation device described in this article has been used in ship draft observation based on AI-assisted proving, which can ease the fluctuation of the wave inside the pipe. Observers can directly read the water surface inside the pipe and compare it to the ship’s draft mark to obtain the final draft, effectively improving draft observation accuracy. However, some surveyors refuse to accept the readings obtained from this device, citing a lack of theoretical basis or the absence of accreditation from relevant technical authorities, leading to the rejection of results. To address these issues, this paper integrates wave energy attenuation theory with PaddlePaddle-OCR recognition to further validate the anti-fluctuation device for accurate ship draft observation. The experimental results are as follows: first, the pipe effectively suppresses the amplitude of external water surface fluctuations by 75%, explaining the fundamental theory that wave heights within the anti-fluctuation device are consistent with external swell heights. When taking a draft measurement, the system dynamically adjusts the position of the main tube in response to the ship’s movements, maintaining the stability of the measurement section and significantly reducing the difficulty of observations. Due to the reduction in fluctuation amplitude, there is a noticeable improvement in observation accuracy.

An Optimal SVD Filtering Method for Measurement Accuracy Improvement against Harmonic Disturbance in Grid-Connected Inverters

An Optimal SVD Filtering Method for Measurement Accuracy Improvement against Harmonic Disturbance in Grid-Connected Inverters

Empirical Approach to Quantifying Sensitivity in Different Chemical Ionization Techniques for Organonitrates and Nitroaromatics Constrained by Ion-Molecule Reaction and Transmission Efficiency.

Accurate identification and quantification of nitro-containing species are of great significance to understanding their chemical behaviors in the atmosphere. By optimizing the operational conditions of the H3O+ and NO+ ionization modes in a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) and evaluating the performance of an iodide chemical ionization mass spectrometer (I- CIMS), this study leveraged the individual advantages of each ionization mode to effectively detect a diverse array of nitroaromatics and organonitrates (ONs). The H3O+ ionization mode largely fulfilled the criteria for real-time monitoring of gas-phase alkyl-, aryl-, and hydroxy-nitrates, and nitrophenols, albeit its reduced sensitivity toward ONs due to extensive fragmentation. In contrast, the NO+ mode demonstrated enhanced sensitivity for ONs with less fragmentation than the H3O+ mode. The I- CIMS featured distinguished sensitivity toward oxidized compounds containing polar functional groups, particularly increasing with the incorporation of hydroxyl, carboxyl, or nitrate groups. Further, we developed a calibration-based semiquantitative framework to enhance the accuracy of sensitivity estimation, constrained by ion-molecule reaction, transmission efficiency, along with possible decomposition of ion-clusters, with uncertainties ranging from 21% to 41% for H3O+ and 21-43% for NO+. Given considerable discrepancies (up to 1 order of magnitude) between measured and predicted sensitivity in I- CIMS using previously reported log-linear fitting, a declustering voltage (dV50)-based categorization approach was introduced, leading to a 5-fold improvement in measurement accuracy and an overall uncertainty of I- CIMS in quantifying nitro-containing species varying from 27% to 60%.

Analysis of orientation errors in triaxial fluxgate sensors and research on their calibration methods

Abstract. Three-axis magnetic flux gate sensors are widely used in Chinese geomagnetic observatories, but due to their directional errors it is necessary to study error correction methods to improve measurement accuracy. Firstly, the mechanism of directional errors produced by three-axis magnetic flux gate sensors is analyzed, followed by the development of measurement tools for conducting directional error measurement experiments on the high-precision three-axis magnetic flux gate sensors of the Chinese FGM-01 series. Experimental results show that correcting the Z-axis and D-axis directional errors is essential. The observation data after error correction, whether in terms of the standard deviation of its all-day baseline values or the relative difference magnitude with the reference instrument, significantly decrease, demonstrating the clear correction effect and proving the effectiveness of this correction method.

Extended Monte Carlo modeling for submicron particle size measurement under high light extinction conditions

The light extinction method (LEM) based on Lambert Beer's law (LB) is widely used to characterize particle size distribution (PSD) in multiphase flow. However, as the optical thickness increases with concentration, the phenomenon of multiple scattering is enhanced, potentially leading to reduced accuracy and a limited application range. In this study, an extended Monte Carlo-based light extinction model (EMC) was developed, which was initially employed to calculate and evaluate the impact of multiple scattering. Subsequently, it was used to predict the extinction spectrum that incorporates multiple scattering effects under varying concentrations. To validate the modeling, a compact setup was constructed to perform a series of experiments on polystyrene and silica dioxide (SiO2) suspensions. A differential evolution algorithm was also implemented for the inversion of PSD based on spectral content, with the incorporation of an improved coefficient matrix that considers multiple scattering effects. In comparison to the linear LB model, the EMC exhibits a markedly enhanced capacity in handling higher particle concentrations and improving measurement accuracy. For a 700 nm PS suspension, the particle size inversion error of the EMC can be kept within 4% (93.86% for the LB model) compared with the nominal value, even with an optical thickness of 5.

Increasing measurement accuracy by estimating multiple dissipations for the impedance tube calibration

Impedance tube measurements, employing transfer function/matrix methods, are commonly used by acousticians to characterize the acoustic properties of materials in normal incident conditions. Sound dissipation in impedance tubes can impact the accuracy of measurement results. Various effects contributing to sound dissipation in tubes are studied and analyzed. This research investigates different dissipative effects and dissipation models. This paper uses model-based Bayesian inference to estimate critical parameters in multiple dissipations. The experiments involve using an empty impedance tube terminated with a rigid metal block. A hypothetical air layer in front of the metal block is assumed for establishing a prediction model in contrasting estimation results with theoretical values. The results incorporating dissipation models demonstrate a good match with the theoretical calculation of the air layer. Applying the estimated dissipations to actual resonator materials demonstrates a significantly improves measurement accuracy.

Comparing Optical and Custom IoT Inertial Motion Capture Systems for Manual Material Handling Risk Assessment Using the NIOSH Lifting Index

Assessing musculoskeletal disorders (MSDs) in the workplace is vital for improving worker health and safety, reducing costs, and increasing productivity. Traditional hazard identification methods are often inefficient, particularly in detecting complex risks, which may compromise risk management. This study introduces a semi-automatic platform using two motion capture systems—an optical system (OptiTrack®) and a Bluetooth Low Energy (BLE)-based system with inertial measurement units (IMUs), developed at the Biomedical Engineering Laboratory, Universidad de Concepción, Chile. These systems, tested on 20 participants (10 women and 10 men, aged 30 ± 9 years without MSDs), facilitate risk assessments via the digitized NIOSH Index method. Analysis of ergonomically significant variables (H, V, A, D) and calculation of the RWL and LI showed both systems aligned with expected ergonomic standards, although significant differences were observed in vertical displacement (V), horizontal displacement (H), and trunk rotation (A), indicating areas for improvement, especially for the BLE system. The BLE Inertial MoCap system recorded mean heights of 33.87 cm (SD = 4.46) and vertical displacements of 13.17 cm (SD = 4.75), while OptiTrack® recorded mean heights of 30.12 cm (SD = 2.91) and vertical displacements of 15.67 cm (SD = 2.63). Despite the greater variability observed in BLE system measurements, both systems accurately captured vertical vertical absolute displacement (D), with means of 32.05 cm (SD = 7.36) for BLE and 31.80 cm (SD = 3.25) for OptiTrack®. Performance analysis showed high precision for both systems, with BLE and OptiTrack® achieving precision rates of 98.5%. Sensitivity, however, was lower for BLE (97.5%) compared to OptiTrack® (98.7%). The BLE system’s F1 score was 97.9%, while OptiTrack® scored 98.6%, indicating both systems can reliably assess ergonomic risk. These findings demonstrate the potential of using BLE-based IMUs for workplace ergonomics, though further improvements in measurement accuracy are needed. The user-friendly BLE-based system and semi-automatic platform significantly enhance risk assessment efficiency across various workplace environments.

Study of the Accuracy and Reliability of Dosimetric Measurements for X-ray Beams with Radiation Qualities N-40, N-100, N-200

Radiation dosimetry is a critical aspect of medical, industrial, and scientific applications involving ionizing radiation. Accurate measurements of radiation doses ensure the safety and effectiveness of radiological practices, which is essential for protecting patients in medical procedures, maintaining safety in industrial applications, and ensuring accuracy in scientific research. Leading international organizations conduct research aimed at improving measurement accuracy and the dissemination of measurement units. One of the methods contributing to this effort is various international projects. The National Scientific Centre “Institute of Metrology” has participated in one such international project. This international project, involving several National Metrology Institutes (NMIs), aimed to improve the accuracy and consistency of radiation dosimetry across Europe. By standardizing measurement and calibration procedures, the project seeks to create a unified system for measuring radiation doses, thereby improving the reliability of ionizing radiation dosimetry. This project is particularly significant given the continuous increase in radiation-based technologies across various fields. For example, precise measurements of ionizing quantities are crucial in the medical field, especially for radiotherapy, to ensure that patients receive the necessary dose with minimal exposure to surrounding healthy tissues. Similarly, in industrial radiography, accurate dosimetry is essential for meeting safety standards and preventing excessive radiation exposure to workers. The international project, with the Physikalisch-Technische Bundesanstalt (PTB) and the Central Office of Measures (GUM) as leading organizations, aims to improve key factors in ionizing radiation dosimetry. These include developing reliable calibration protocols for various types of radiation, establishing traceability chains to ensure measurement accuracy, and sharing best dosimetry practices among project participants. Preliminary comparisons were performed between NMIs, with two control participants serving as references while other NMIs participated anonymously (knowing only their number and the numbers of the reference participants). Each participant had the opportunity to compare their obtained values with the reference values and make adjustments for future measurements. The collaborative nature of such cooperation also promotes knowledge and experience exchange, fostering innovation and improvement in dosimetry techniques. The NSC “Institute of Metrology”, a leading organization in the field of the ionizing radiation metrology, has actively participated in this project as a representative from Ukraine. The paper presents the results of international comparisons for X-ray beams with the radiation qualities N-40, N-100, N-200.

Stereo Bi-Telecentric Phase-Measuring Deflectometry.

Replacing the endocentric lenses in traditional Phase-Measuring Deflectometry (PMD) with bi-telecentric lenses can reduce the number of parameters to be optimized during the calibration process, which can effectively increase both measurement precision and efficiency. Consequently, the low distortion characteristics of bi-telecentric PMD contribute to improved measurement accuracy. However, the calibration of the extrinsic parameters of bi-telecentric lenses requires the help of a micro-positioning stage. Using a micro-positioning stage for the calibration of external parameters can result in an excessively cumbersome and time-consuming calibration process. Thus, this study proposes a holistic and flexible calibration solution for which only one flat mirror in three poses is needed. In order to obtain accurate measurement results, the calibration residuals are utilized to construct the inverse distortion map through bicubic Hermite interpolation in order to obtain accurate anchor positioning result. The calibrated stereo bi-telecentric PMD can achieve 3.5 μm (Peak-to-Valley value) accuracy within 100 mm (Width) × 100 mm (Height) × 200 mm (Depth) domain for various surfaces. This allows the obtaining of reliable measurement results without restricting the placement of the surface under test.

Mobile Devices in Forest Mensuration: A Review of Technologies and Methods in Single Tree Measurements

Mobile devices such as smartphones, tablets or similar devices are becoming increasingly important as measurement devices in forestry due to their advanced sensors, including RGB cameras and LiDAR systems. This review examines the current state of applications of mobile devices for measuring biometric characteristics of individual trees and presents technologies, applications, measurement accuracy and implementation barriers. Passive sensors, such as RGB cameras have proven their potential for 3D reconstruction and analysing point clouds that improve single tree-level information collection. Active sensors with LiDAR-equipped smartphones provide precise quantitative measurements but are limited by specific hardware requirements. The combination of passive and active sensing techniques has shown significant potential for comprehensive data collection. The methods of data collection, both physical and digital, significantly affect the accuracy and reproducibility of measurements. Applications such as ForestScanner and TRESTIMATM have automated the measurement of tree characteristics and simplified data collection. However, environmental conditions and sensor limitations pose a challenge. There are also computational obstacles, as many methods require significant post-processing. The review highlights the advances in mobile device-based forestry applications and emphasizes the need for standardized protocols and cross-device benchmarking. Future research should focus on developing robust algorithms and cost-effective solutions to improve measurement accuracy and accessibility. While mobile devices offer significant potential for forest surveying, overcoming the above-mentioned challenges is critical to optimizing their application in forest management and protection.

Experimental Investigation on the Effect of Coil Shape on Planar Eddy Current Sensor Characteristic for Blade Tip Clearance.

Given the increasing application of eddy current sensors for measuring turbine tip clearance in aero engines, enhancing the performance of these sensors is essential for improving measurement accuracy. This study investigates the influence of coil shape on the measurement performance of planar eddy current sensors and identifies an optimal coil shape to enhance sensing capabilities. To achieve this, various coil shapes-specifically circular, square, rectangular wave, and triangular wave-were designed and fabricated, featuring different numbers of turns for the experiment at room temperature. By employing a method for calculating coil inductance, the performance of each sensor was evaluated based on key metrics: measurement range, sensitivity, and linearity. Experimental results reveal that the square coil configuration outperforms other shapes in overall measurement performance. Notably, the square coil demonstrated a measurement range of 0 mm to 8 mm, a sensitivity of 0.115685 μH/mm, and an impressive linearity of 98.41% within the range of 0 mm to 2 mm. These findings indicate that the square coil configuration enhances measurement capabilities. The conclusions drawn from this study provide valuable insights for selecting coil shapes and optimizing the performance of planar eddy current sensors, thereby contributing to the advancement of turbine tip clearance measurement techniques in aero engines.

Research on novel hybrid structure AACMM based on 3-RPS parallel mechanism

Abstract The articulated arm coordinate measuring machine (AACMM), widely utilized in the field of industrial measurement, is assessed based on key performance indicators such as measurement accuracy, measurement space, and flexibility. To enhance these aspects of the AACMM, this paper introduces a novel type of AACMM. The new model is based on a 3-RPS (revolute joint R, prismatic joint P, spherical joint S) parallel mechanism (3-RPSPM). The working principle of the 3-RPSPM is detailed, and a corresponding computational model is established. An algorithm is proposed based on this mathematical model to determine the theoretical achievable accuracy of the 3-RPSPM. Additionally, a spatial error analysis of the 3-RPSPM is conducted to verify its compliance with AACMM accuracy requirements and to demonstrate a certain level of accuracy improvement. Through simulation analysis, the differences in measurement accuracy, measurement space, and flexibility between the new type of AACMM based on the 3-RPS parallel mechanism (3-RPSAACMM) and traditional AACMMs are compared. The results indicate that the 3-RPSAACMM, with its novel parallel structure free from series accumulation errors, not only maintains measurement flexibility but also achieves improvements in measurement accuracy and space. The hybrid structure adopted by the new 3-RPSAACMM offers a new direction for the future development of AACMMs, presenting significant research value and application prospects.

Deep learning based measurement accuracy improvement of high dynamic range objects in fringe projection profilometry

One of the key factors affecting the accuracy of three-dimensional (3D) measurement in fringe projection profilometry (FPP) is the phase retrieve accuracy. In the 3D measurement of high dynamic range (HDR) objects, fringe saturation and/or low contrast are difficult to avoid. A greater number of fringe images are needed for 3D measurement of HDR objects by traditional methods, which is unfavorable for the measurement of moving objects. In this paper, what we believe to be a new method to solve the phase demodulation problem of HDR objects using deep learning is proposed. In this method, a “many-to-one” mapping relationship is established using an improved UNet deep neural network. In addition, in order to obtain more saturated fringe information, π-shifted binary fringes were also used. This allows us to retrieve the wrapped phase of HDR objects quickly and accurately. Experimental results demonstrate the effectiveness and reliability of the proposed method.

Accurately Measuring the Infrared Spectral Emissivity of Inconel 601, Inconel 625, and Inconel 718 Alloys during the Oxidation Process.

Accurate measurement of the infrared spectral emissivity of nickel-based alloys is significant for applications in aerospace. The low thermal conductivity of these alloys limits the accuracy of direct emissivity measurement, especially during the oxidation process. To improve measurement accuracy, a surface temperature correction method based on two thermocouples was proposed to eliminate the effect of thermal conductivity changes on emissivity measurement. By using this method, the infrared spectral emissivity of Inconel 601, Inconel 625, and Inconel 718 alloys was accurately measured during the oxidation process, with a temperature range of 673-873 K, a wavelength range of 3-20 μm, and a zenith angle range of 0-80°. The results show that the emissivity of the three alloys is similar in value and variation law; the emissivity of Inconel 718 is slightly less than that of Inconel 601 and Inconel 625; and the spectral emissivity of the three alloys strongly increases in the first hour, whereafter it grows gradually with the increase in oxidation time. Finally, Inconel 601 has a lower emissivity growth rate, which illustrates that it possesses stronger oxidation resistance and thermal stability. The maximum relative uncertainty of the emissivity measurement of the three alloys does not exceed 2.6%, except for the atmospheric absorption wavebands.