Standardization is necessary for the early industrialization of the new materials and technology.It is achieved by having agreed practices for the measurement of properties and other characteristics.The promising use ...Standardization is necessary for the early industrialization of the new materials and technology.It is achieved by having agreed practices for the measurement of properties and other characteristics.The promising use of graphene-based materials in fields like electronics,energy,and composites has resulted in standards for their nomenclature,the measurement of key characteristics,and their specification,etc.Among these,standards for measuring the key characteristics are crucial.The critical parameters are the number of layers,the type and concentration of defects and functional groups,elemental composition,sheet resistance,and carrier mobility.Standards for characterizing these have been analyzed by the International Organization for Standardization Technical Committee in ISO/TC229 and the International Electrotechnical Commission Technical Committee in IEC/TC113.These give details of applicable or preferred samples,the fundamental principles of the techniques,specific precautions,and points for attention in the relevant standards.The pivotal role of the ISO/TC229 and IEC/TC113 standards is considered and challenges and future trends are outlined.展开更多
Resourceful food waste treatment is essential for promoting the sustainable development of anaerobic digestion and realizing a circular economy.In this study,biogas residue(BR)was used as a feedstock to produce highva...Resourceful food waste treatment is essential for promoting the sustainable development of anaerobic digestion and realizing a circular economy.In this study,biogas residue(BR)was used as a feedstock to produce highvalue-added products(gas,tar,and char-derived high-performance adsorbents)using pyrolysis technology(at 400–800℃).CaCO_(3),the major component of ash,significantly improved the quality of the pyrolysis product by decomposing into CO_(2) and CaO.The gasification reaction of CO_(2) with coke generated substantial CO and facilitated the formation of a rich pore structure in the char.CaO improved tar quality by contributing to secondary cracking reactions and reducing water content.The composite material formed exhibited excellent performance in wastewater treatment,with a maximum methylene blue adsorption capacity of 969.30 mg/g.The maximum adsorption of heavy metals Cu^(2+),Pb^(2+),and Cd^(2+)was 175.44,244.93,and 199.50 mg/g,respectively.The ash fraction on the ash-biochar composite material adsorbent surface enhanced pollutant removal by providing an alkaline adsorption environment and more oxygen-based n-π interaction sites.The economic analysis showed that the high value-added products obtained from the pyrolysis of BR make this process more productive than land use.展开更多
The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbi...The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.展开更多
The electrocatalytic oxidation of ethylene glycol(EG)into high-value chemicals like glycolic acid(GA)is a crucial step for upcycling waste plastics.However,catalyst deactivation and low selectivity pose significant ch...The electrocatalytic oxidation of ethylene glycol(EG)into high-value chemicals like glycolic acid(GA)is a crucial step for upcycling waste plastics.However,catalyst deactivation and low selectivity pose significant challenges.This work presents the low-coordination PtBi nanosheets(LC-PtBi NSs),featuring a unique amorphous-crystalline heterostructure with a low coordination number of 2.3-2.5.They can exhibit exceptional mass activity(8.3 A mg_(Pt)^(-1))and stability(maintaining 88.7%of initial activity after running for 3600 s)of the EG oxidation reaction(EGOR).They also achieve over 90%apparent selectivity for EG-to-GA conversion at low potentials(<0.7 V vs.RHE)and even more than 100-h continuous electrolysis.Density fu nctional theory(DFT)calculations reveal that the low-coordination PtBi heterogeneous interface is responsible for the high coverage of OH_(ad) species and weakened adsorption of carbonaceous intermediates on LC-PtBi NSs,thereby promoting the direct oxidation of C_(2) intermediates to GA.This work demonstrates a strategy of doping-mediated catalytic interface regulation and electron density rearrangement,offering insights for designing efficient Pt-based electrocatalysts toward selective oxidation of small molecules.展开更多
AIM:To evaluate the differences and consistency of vault measurements obtained by Scheimpflug tomography(Pentacam),anterior segment optical coherence tomography(AS-OCT,CASIA II),and ultrasound biomicroscopy(UBM)follow...AIM:To evaluate the differences and consistency of vault measurements obtained by Scheimpflug tomography(Pentacam),anterior segment optical coherence tomography(AS-OCT,CASIA II),and ultrasound biomicroscopy(UBM)following implantable collamer lens(ICL)V4c implantation.METHODS:Vault measurements were acquired using three modalities:Pentacam,CASIA II AS-OCT,and UBM.Repeated-measures analysis of variance was used to compare the vault values obtained by the three devices.The correlation and consistency of measurements among the three instruments were assessed using the Pearson correlation coefficient,intraclass correlation coefficient(ICC),and Bland-Altman plots.RESULTS:This retrospective study enrolled 210 myopic eyes of 210 patients(158 women and 52 men)who underwent ICL implantation:108 eyes had a myopic ICL V4c implanted,and 102 eyes had a toric ICL V4c implanted.The mean vault values measured by Pentacam,CASIA II,and UBM were 452.64±204.20μm,538.57±203.54μm,and 560.95±227.54μm,respectively,with statistically significant differences among the three groups(P<0.05).Pearson correlation analysis showed strong positive correlations between vault values measured by different instruments(all P<0.001).ICC results indicated good consistency among the three measurement modalities(all P<0.001).Stratified analysis revealed that when the vault value was≤250μm,the correlation and consistency of measurements across the three instruments were lower than those in the medium and high vault subgroups.CONCLUSION:Vault values measured by Pentacam are lower than those obtained by CASIA II and UBM,with UBM yielding the highest mean vault values.Measurements from the three instruments are not interchangeable but can serve as mutual references due to their significant correlation and good overall consistency.Pentacam and CASIA II demonstrate the highest consistency in vault measurement.Notably,when the vault value is≤250μm,the consistency between Pentacam and the other two instruments decreases significantly.展开更多
Low-visibility phenomena strongly impact the environment,as well as transportation,aviation and other fields that are closely related to people's livelihoods;thus,they represent important ecological issues of soci...Low-visibility phenomena strongly impact the environment,as well as transportation,aviation and other fields that are closely related to people's livelihoods;thus,they represent important ecological issues of social concern.Based on observation data concerning low-visibility phenomena derived from 105 national meteorological stations in Xinjiang,China over the past 20 years,we systematically analyzed the differences between manual and instrument observations for six types of low-visibility phenomena,with a focus on exploring their spatiotemporal distribution characteristics using instrument data.The results revealed that low-visibility phenomena were dominated by fog-and haze-related events(mist,fog,and haze)in northern Xinjiang and dust-related events(dust storms,blowing sand,and floating dust)in southern Xinjiang,with transitional characteristics observed in eastern Xinjiang.Compared with manual observations,the instrument measurements significantly improved the fine-scale low-visibility phenomenon identification process.On the basis of the instrument observation data,spatial-dimension analysis results indicated that low-visibility phenomena in Xinjiang were significantly influenced by terrain factors.Constrained by the Tianshan Mountains,haze-like phenomena formed a core agglomeration area in northern Xinjiang,whereas dust-and sand-related phenomena radiated outward,with the Taklimakan Desert at the center.Moreover,the gripping effect of the terrain promoted dust transmission along low-altitude channels.Temporally,fog-and haze-related phenomena occurred mainly during autumn and winter,and the proportion of these events decreased from 76.7%to 55.1%.The fog-and haze-related phenomena demonstrated a U-shaped rebound trend,while the proportion of mist phenomena decreased by 34.2%.Dust storms occurred during spring,accounting for 23.3%to 44.9%of all storms.Instrument measurement technology has the advantages of high spatial and temporal resolutions and multiparameter coordination but provides a limited dust-haze mixed-pollution identification capacity.This study provides crucial reference data for enhancing the understanding of low-visibility events in Xinjiang and the potential responses while improving the accuracy of pollution source tracking and meteorological process diagnosis tasks.展开更多
The segmented solar telescope described in this study employs a simultaneous dual-wavelength measurement technique to achieve co-phase alignment.To meet the measurement requirements of a 20μm range,5 nm root mean squ...The segmented solar telescope described in this study employs a simultaneous dual-wavelength measurement technique to achieve co-phase alignment.To meet the measurement requirements of a 20μm range,5 nm root mean square precision,and edge jump rates of<10^(−6),this study focused on calibrating the dual-wavelength measurement system for the segmented-mirror solar telescope.Analysis of the relative error in the measurement system revealed that assembly-induced errors such as defocus,translation,scaling,and rotation markedly degrade measurement accuracy.To address these issues,we propose a defocus error compensation algorithm,based on the light intensity distribution of the point spread function(PSF)and an affine transformation model,to calibrate spatial pose deviations across the two measurement channels.A dual-wavelength measurement system was implemented on a segmented-mirror experimental platform for calibration.Experimental results demonstrated that the mean relative error decreased from−0.6423 to−0.0345 nm after calibration,reflecting improved reliability and stability of the co-phase measurements.展开更多
Single-cell biomechanics and electrophysiology measuring tools have transformed biological research over the last few decades,which enabling a comprehensive and nuanced understanding of cellular behavior and function....Single-cell biomechanics and electrophysiology measuring tools have transformed biological research over the last few decades,which enabling a comprehensive and nuanced understanding of cellular behavior and function.Despite their high-quality information content,these single-cell measuring techniques suffer from laborious manual processing by highly skilled workers and extremely low throughput(tens of cells per day).Recently,numerous researchers have automated the measurement of cell mechanical and electrical signals through robotic localization and control processes.While these efforts have demonstrated promising progress,critical challenges persist,including human dependency,learning complexity,in-situ measurement,and multidimensional signal acquisition.To identify key limitations and highlight emerging opportunities for innovation,in this review,we comprehensively summarize the key steps of robotic technologies in single-cell biomechanics and electrophysiology.We also discussed the prospects and challenges of robotics and automation in biological research.By bridging gaps between engineering,biology,and data science,this work aims to stimulate interdisciplinary research and accelerate the translation of robotic single-cell technologies into practical applications in the life sciences and medical fields.展开更多
Transit managers can use Intelligent Transportation System technologies to access large amounts of data to monitor network status.However,the presentation of the data lacks structural information.Existing single-netwo...Transit managers can use Intelligent Transportation System technologies to access large amounts of data to monitor network status.However,the presentation of the data lacks structural information.Existing single-network description technologies are ineffective in representing the temporal and spatial characteristics simultaneously.Therefore,there is a need for complementary methods to address these deficiencies.To address these limitations,this paper proposes an approach that combines Network Snapshots and Temporal Paths for the scheduled system.A dual information network is constructed to assess the degree of operational deviation considering the planning tasks.To validate the effectiveness,discussions are conducted through a modified cosine similarity calculation on theoretical analysis,delay level description,and the ability to identify abnormal dates.Compared to some state-of-the-art methods,the proposed method achieves an average Spearman delay correlation of 0.847 and a relative distance of 3.477.Furthermore,case analyses are invested in regions of China's Mainland,Europe,and the United States,investigating both the overall and sub-regional network fluctuations.To represent the impact of network fluctuations in sub-regions,a response loss value was developed.The times that are prone to fluctuations are also discussed through the classification of time series data.The research can offer a novel approach to system monitoring,providing a research direction that utilizes individual data combined to represent macroscopic states.Our code will be released at https://github.com/daozhong/STPN.git.展开更多
[Significance]In alignment with the national germplasm security strategy,current research efforts are accelerating the adoption of precision breeding in sheep.Within the whole-genome selection,accurate phenotyping of ...[Significance]In alignment with the national germplasm security strategy,current research efforts are accelerating the adoption of precision breeding in sheep.Within the whole-genome selection,accurate phenotyping of body morphometrics is critical for assessing growth performance and breeding value.Traditional manual measurements are inefficient,prone to human error,and may cause stress to sheep,limiting their suitability for precision sheep management.By summarizing the applications of sheep body size measurement technologies and analyzing their development directions,this paper provides theoretical references and practical guidance for the research and application of non contact sheep body size measurement.[Progress]This review synthesizes progress across three principal methodological paradigms:two-dimensional(2D)image-based techniques,three-dimensional(3D)point cloud-based approaches,and integrated 2D-3D fusion systems.2D methods,employing either handcrafted geometric features or deep learning-based keypoint detector algorithms,are cost-effective and operationally simple but sensitive to variation in imaging conditions and unable to capture critical circumference metrics.3D point-cloud approaches enable precise reconstruction of full animal morphology,supporting comprehensive body-size acquisition with higher accuracy,yet face challenges including high hardware costs,complex data workflows,and sensitivity to posture variability.Hybrid 2D-3D fusion systems combine semantic richness from RGB imagery with geometric completeness from point clouds.Having been effectively validated in other livestock specise,e.g.,cattle and pigs,these fusion systems have demonstrated excellent performance,providing important technical references and practical insights for sheep body size measurement.[Conclusions and Prospects]Firstly,future research should focus on constructing large-scale,high-quality datasets for sheep body size measurement that encompass diverse breeds,growth stages,and environmental conditions,thereby enhancing model robustness and generalization.Secondly,the development of lightweight artificial intelligence models is essential.Techniques such as model compression,quantization,and algorithmic optimization can substantially reduce computational complexity and storage requirements,facilitating deployment in resource-constrained environments.Thirdly,the 3D point cloud processing pipeline should be streamlined to improve the efficiency of data acquisition,filtering,registration,and segmentation,while promoting the integration of low-cost,high-resilience vision systems into practical farming scenarios.Fourthly,specific emphasis should be placed on improving the accuracy of curved-dimensional measurements,such as chest circumference,abdominal circumference,and shank circumference,through advances in pose standardization,refined 3D segmentation strategies,and multimodal data fusion.Finally,the cross-fertilization of sheep body size measurement technologies with analogous methods for other livestock species offers a promising pathway for mutual learning and collaborative innovation,accelerating the industrialization of automated sheep morphometric systems and supporting the development of intelligent,data-driven pasture management practices.展开更多
As one of the major volatile components in extraterrestrial materials,nitrogen(N_(2))isotopes serve not only as tracers for the formation and evolution of the solar system,but also play a critical role in assessing pl...As one of the major volatile components in extraterrestrial materials,nitrogen(N_(2))isotopes serve not only as tracers for the formation and evolution of the solar system,but also play a critical role in assessing planetary habitability and the search for extraterrestrial life.The integrated measurement of N_(2)and argon(Ar)isotopes by using noble gas mass spectrometry represents a state-of-the-art technique for such investigations.To support the growing demands of planetary science research in China,we have developed a high-efficiency,high-precision method for the integrated analysis of N_(2)and Ar isotopes.This was achieved by enhancing gas extraction and purification systems and integrating them with a static noble gas mass spectrometer.This method enables integrated N_(2)-Ar isotope measurements on submilligram samples,significantly improving sample utilization and reducing the impact of sample heterogeneity on volatile analysis.The system integrates CO_(2)laser heating,a modular two-stage Zr-Al getter pump,and a CuO furnace-based purification process,effectively reducing background levels(N_(2)blank as low as 0.35×10^(−6)cubic centimeters at standard temperature and pressure[ccSTP]).Analytical precision is ensured through calibration with atmospheric air and CO corrections.To validate the reliability of the method,we performed N_(2)-Ar isotope analyses on the Allende carbonaceous chondrite,one of the most extensively studied meteorites internationally.The measured N_(2)concentrations range from 19.2 to 29.8 ppm,withδ15N values between−44.8‰and−33.0‰.Concentrations of 40Ar,36Ar,and 38Ar are(12.5-21.1)×10^(−6)ccSTP/g,(90.9-150.3)×10^(−9)ccSTP/g,and(19.2-30.7)×10^(−9)ccSTP/g,respectively.These values correspond to cosmic-ray exposure ages of 4.5-5.7 Ma,consistent with previous reports.Step-heating experiments further reveal distinct release patterns of N and Ar isotopes,as well as their associations with specific mineral phases in the meteorite.In summary,the combined N_(2)-Ar isotopic system offers significant advantages for tracing volatile sources in extraterrestrial materials and will provide essential analytical support for upcoming Chinese planetary missions,such as Tianwen-2.展开更多
A new multi-detector array named HALIMA(Hybrid Array for LIfetime MeAsurement)has been developed at Lanzhou for nuclear structure studies in fission.The array comprises eight BGO-shielded High-Purity Germanium detecto...A new multi-detector array named HALIMA(Hybrid Array for LIfetime MeAsurement)has been developed at Lanzhou for nuclear structure studies in fission.The array comprises eight BGO-shielded High-Purity Germanium detectors and twenty fast Ce-doped Lanthanum Bromide[LaBr_(3)(Ce)]detectors shielded with CsI(Tl).HALIMA is further complemented by two ancillary detector systems:fission fragment(FF)detectors and β detectors.This configuration enables precise sub-nanosecond lifetime measurements using the fourfold FF/β-Ge-LaBr_(3)(Ce)-LaBr_(3)(Ce)coincidence technique.The performance and specifications of the detectors,associated electronics,and the data acquisition system are presented in detail.The advantage of FF selectivity is emphasized,which significantly enhances sensitivity to specific fission channels.Using this approach,the lifetimes of the nuclear excited states populated in the spontaneous fission of^(252)Cf were measured,showing good agreement with the established literature values.展开更多
As the enlightenment stage of students’Chinese learning,primary school Chinese education plays a key role in cultivating students’language ability,thinking development,and humanistic literacy.Value-added evaluation,...As the enlightenment stage of students’Chinese learning,primary school Chinese education plays a key role in cultivating students’language ability,thinking development,and humanistic literacy.Value-added evaluation,as an evaluation method that focuses on the changes in students’individual development and attaches importance to the learning process,has gradually attracted attention in the application of primary school Chinese education.This paper first analyzes the problems existing in the current implementation of value-added evaluation in primary school Chinese,and then explores the countermeasures to improve the effectiveness of value-added evaluation in primary school Chinese from the aspects of evaluation concept,evaluation content,evaluation method,evaluation subject,and application of evaluation results.The purpose is to provide strong support for the improvement of primary school Chinese teaching quality and the all-round development of students.展开更多
Value-added evaluation focuses on individual student growth by tracking changes in academic performance,skills,literacy,etc.,at different time points.It weakens horizontal comparisons and emphasizes vertical progress ...Value-added evaluation focuses on individual student growth by tracking changes in academic performance,skills,literacy,etc.,at different time points.It weakens horizontal comparisons and emphasizes vertical progress to more fairly reflect educational effectiveness.This evaluation method is particularly suitable for vocational education,effectively motivating students’learning enthusiasm and enhancing their self-confidence.Foreign research is represented by the Tennessee Value-Added Assessment System(TVAAS),widely used in evaluating school quality and teacher performance.Domestic research currently focuses on the theoretical construction,model establishment,optimization,and practical application of value-added evaluation,still facing significant challenges in data collection comprehensiveness and model adaptability.Aiming at current issues,this study focuses on exploring the application of artificial intelligence large models in student value-added evaluation from an evidence-based perspective,committed to constructing an innovative evidence-based value-added evaluation system.It aims to achieve precise assessment of students’learning effect“net value-added”through multi-source data collection,intelligent analysis,and personalized feedback.The system integrates outcome evaluation,process evaluation,value-added evaluation,and comprehensive evaluation to form a“four-in-one”dynamic evaluation framework,considering students’starting points,process performance,and final achievements.In the future,value-added evaluation needs to further expand the assessment of non-academic dimensions(such as professional literacy and social-emotional skills)and explore the application of non-linear models to promote the deepening and innovation of educational evaluation reform.展开更多
Based on the educational evaluation reform,this study explores the construction of an evidence-based value-added evaluation system based on data-driven,aiming to solve the limitations of traditional evaluation methods...Based on the educational evaluation reform,this study explores the construction of an evidence-based value-added evaluation system based on data-driven,aiming to solve the limitations of traditional evaluation methods.The research adopts the method of combining theoretical analysis and practical application,and designs the evidence-based value-added evaluation framework,which includes the core elements of a multi-source heterogeneous data acquisition and processing system,a value-added evaluation agent based on a large model,and an evaluation implementation and application mechanism.Through empirical research verification,the evaluation system has remarkable effects in improving learning participation,promoting ability development,and supporting teaching decision-making,and provides a theoretical reference and practical path for educational evaluation reform in the new era.The research shows that the evidence-based value-added evaluation system based on data-driven can reflect students’actual progress more fairly and objectively by accurately measuring the difference in starting point and development range of students,and provide strong support for the realization of high-quality education development.展开更多
The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts....The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.展开更多
Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predomina...Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predominantly on the phase-shifting approach,which involves collecting multiple interferograms and imposes stringent demands on environmental stability.These issues significantly hinder its ability to achieve real-time and dynamic high-precision measurements.Therefore,this study proposes a high-precision large-aperture single-frame interferometric surface profile measurement(LA-SFISPM)method based on deep learning and explores its capability to realize dynamic measurements with high accuracy.The interferogram is matched to the phase by training the data measured using the small aperture.The consistency of the surface features of the small and large apertures is enhanced via contrast learning and feature-distribution alignment.Hence,high-precision phase reconstruction of large-aperture optical components can be achieved without using a phase shifter.The experimental results show that for the tested mirror withΦ=820 mm,the surface profile obtained from LA-SFISPM is subtracted point-by-point from the ground truth,resulting in a maximum single-point error of 4.56 nm.Meanwhile,the peak-to-valley(PV)value is 0.0758λ,and the simple repeatability of root mean square(SR-RMS)value is 0.00025λ,which aligns well with the measured results obtained by ZYGO.In particular,a significant reduction in the measurement time(reduced by a factor of 48)is achieved compared with that of the traditional phase-shifting method.Our proposed method provides an efficient,rapid,and accurate method for obtaining the surface profiles of optical components with different diameters without employing a phase-shifting approach,which is highly desired in large-aperture interferometric measurement systems.展开更多
Radar cross section(RCS)plays a critical role in modeling target scattering characteristics and enhancing the precision of target detection and localization in integrated sensing and communication(ISAC)systems.This pa...Radar cross section(RCS)plays a critical role in modeling target scattering characteristics and enhancing the precision of target detection and localization in integrated sensing and communication(ISAC)systems.This paper investigates the human body RCS at 26 GHz via multiangle channel measurements under different clothing conditions.Based on calibrated electromagnetic(EM)parameters,the RCS characteristics of the human body in far-field conditions are analyzed using ray-tracing(RT)simulations.Some suggestions for the design of ISAC systems are also discussed.The results provide a solid theoretical foundation and practical reference for the modeling of target scattering characteristics for ISAC channels.展开更多
Accurate measurement of helicopter rotor motion parameters(flap,lead-lag,torsion,and azimuth angles)is essential for rotor blade design,helicopter dynamics modeling,and flight safety and health monitoring.However,the ...Accurate measurement of helicopter rotor motion parameters(flap,lead-lag,torsion,and azimuth angles)is essential for rotor blade design,helicopter dynamics modeling,and flight safety and health monitoring.However,the existing methods face challenges in testing equipment installation,calibration,and data transmission,resulting in limited reports on real-time in-flight measurements of blade motion parameters.This paper proposes a non-contact optoelectronic method based on two-dimensional position-sensitive detectors for in-flight measurement and a ground calibration system to obtain real-time rotor motion parameters during helicopter flight.The proposed method establishes the time evolution relationship of rotor motion parameters and verifies the performance of the in-flight measurement system regarding measurement resolution and accuracy through the construction of a blade motion posture experimental platform.The proposed method has been applied to the flight measurement of a medium-sized single-rotor helicopter,and the obtained results have been compared with theoretical analysis outcomes.Furthermore,this paper examines the characteristics of blade motion parameters during flight and discusses the challenges and potential solutions for measuring rotor motion parameters during helicopter flight using the proposed method.展开更多
Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel perf...Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel performance-based fault detection and identification(FDI)strategy for twin-shaft turbofan gas turbine engines and addresses these uncertainties through a first-order Takagi-Sugeno-Kang fuzzy inference system.To handle ambient condition changes,we use parameter correction to preprocess the raw measurement data,which reduces the FDI’s system complexity.Additionally,the power-level angle is set as a scheduling parameter to reduce the number of rules in the TSK-based FDI system.The data for designing,training,and testing the proposed FDI strategy are generated using a component-level turbofan engine model.The antecedent and consequent parameters of the TSK-based FDI system are optimized using the particle swarm optimization algorithm and ridge regression.A robust structure combining a specialized fuzzy inference system with the TSK-based FDI system is proposed to handle measurement biases.The performance of the first-order TSK-based FDI system and robust FDI structure are evaluated through comprehensive simulation studies.Comparative studies confirm the superior accuracy of the first-order TSK-based FDI system in fault detection,isolation,and identification.The robust structure demonstrates a 2%-8%improvement in the success rate index under relatively large measurement bias conditions,thereby indicating excellent robustness.Accuracy against significant bias values and computation time are also evaluated,suggesting that the proposed robust structure has desirable online performance.This study proposes a novel FDI strategy that effectively addresses measurement uncertainties.展开更多
文摘Standardization is necessary for the early industrialization of the new materials and technology.It is achieved by having agreed practices for the measurement of properties and other characteristics.The promising use of graphene-based materials in fields like electronics,energy,and composites has resulted in standards for their nomenclature,the measurement of key characteristics,and their specification,etc.Among these,standards for measuring the key characteristics are crucial.The critical parameters are the number of layers,the type and concentration of defects and functional groups,elemental composition,sheet resistance,and carrier mobility.Standards for characterizing these have been analyzed by the International Organization for Standardization Technical Committee in ISO/TC229 and the International Electrotechnical Commission Technical Committee in IEC/TC113.These give details of applicable or preferred samples,the fundamental principles of the techniques,specific precautions,and points for attention in the relevant standards.The pivotal role of the ISO/TC229 and IEC/TC113 standards is considered and challenges and future trends are outlined.
基金supported by the National Natural Science Foundation of China(Nos.52192684,52270136,and U2340214).
文摘Resourceful food waste treatment is essential for promoting the sustainable development of anaerobic digestion and realizing a circular economy.In this study,biogas residue(BR)was used as a feedstock to produce highvalue-added products(gas,tar,and char-derived high-performance adsorbents)using pyrolysis technology(at 400–800℃).CaCO_(3),the major component of ash,significantly improved the quality of the pyrolysis product by decomposing into CO_(2) and CaO.The gasification reaction of CO_(2) with coke generated substantial CO and facilitated the formation of a rich pore structure in the char.CaO improved tar quality by contributing to secondary cracking reactions and reducing water content.The composite material formed exhibited excellent performance in wastewater treatment,with a maximum methylene blue adsorption capacity of 969.30 mg/g.The maximum adsorption of heavy metals Cu^(2+),Pb^(2+),and Cd^(2+)was 175.44,244.93,and 199.50 mg/g,respectively.The ash fraction on the ash-biochar composite material adsorbent surface enhanced pollutant removal by providing an alkaline adsorption environment and more oxygen-based n-π interaction sites.The economic analysis showed that the high value-added products obtained from the pyrolysis of BR make this process more productive than land use.
基金supported by the National Natural Science Foundation of China(No.52436008)the Inner Mongolia Science and Technology Projects,China(Nos.JMRHZX20210003 and 2023YFCY0009)+3 种基金the Huaneng Group Co Ltd.,China(No.HNKJ23-H50)the National Natural Science Foundation of China(No.22408044)the China Postdoctoral Science Foundation(No.2024M761877)the National Key R&D Program of China(No.SQ2024YFD2200039)。
文摘The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.
基金supported by the National Natural Science Foundation of China(NSFC,No.22172121)the Fundamental Research Funds for the Central Universities(No.ZYN2025267)Southwest Minzu University。
文摘The electrocatalytic oxidation of ethylene glycol(EG)into high-value chemicals like glycolic acid(GA)is a crucial step for upcycling waste plastics.However,catalyst deactivation and low selectivity pose significant challenges.This work presents the low-coordination PtBi nanosheets(LC-PtBi NSs),featuring a unique amorphous-crystalline heterostructure with a low coordination number of 2.3-2.5.They can exhibit exceptional mass activity(8.3 A mg_(Pt)^(-1))and stability(maintaining 88.7%of initial activity after running for 3600 s)of the EG oxidation reaction(EGOR).They also achieve over 90%apparent selectivity for EG-to-GA conversion at low potentials(<0.7 V vs.RHE)and even more than 100-h continuous electrolysis.Density fu nctional theory(DFT)calculations reveal that the low-coordination PtBi heterogeneous interface is responsible for the high coverage of OH_(ad) species and weakened adsorption of carbonaceous intermediates on LC-PtBi NSs,thereby promoting the direct oxidation of C_(2) intermediates to GA.This work demonstrates a strategy of doping-mediated catalytic interface regulation and electron density rearrangement,offering insights for designing efficient Pt-based electrocatalysts toward selective oxidation of small molecules.
基金Supported by the National Natural Science Foundation of China(No.82171095)the Project of Shanghai Science and Technology(No.23XD1400500)the Research Fund of Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital(No.24QNPY049).
文摘AIM:To evaluate the differences and consistency of vault measurements obtained by Scheimpflug tomography(Pentacam),anterior segment optical coherence tomography(AS-OCT,CASIA II),and ultrasound biomicroscopy(UBM)following implantable collamer lens(ICL)V4c implantation.METHODS:Vault measurements were acquired using three modalities:Pentacam,CASIA II AS-OCT,and UBM.Repeated-measures analysis of variance was used to compare the vault values obtained by the three devices.The correlation and consistency of measurements among the three instruments were assessed using the Pearson correlation coefficient,intraclass correlation coefficient(ICC),and Bland-Altman plots.RESULTS:This retrospective study enrolled 210 myopic eyes of 210 patients(158 women and 52 men)who underwent ICL implantation:108 eyes had a myopic ICL V4c implanted,and 102 eyes had a toric ICL V4c implanted.The mean vault values measured by Pentacam,CASIA II,and UBM were 452.64±204.20μm,538.57±203.54μm,and 560.95±227.54μm,respectively,with statistically significant differences among the three groups(P<0.05).Pearson correlation analysis showed strong positive correlations between vault values measured by different instruments(all P<0.001).ICC results indicated good consistency among the three measurement modalities(all P<0.001).Stratified analysis revealed that when the vault value was≤250μm,the correlation and consistency of measurements across the three instruments were lower than those in the medium and high vault subgroups.CONCLUSION:Vault values measured by Pentacam are lower than those obtained by CASIA II and UBM,with UBM yielding the highest mean vault values.Measurements from the three instruments are not interchangeable but can serve as mutual references due to their significant correlation and good overall consistency.Pentacam and CASIA II demonstrate the highest consistency in vault measurement.Notably,when the vault value is≤250μm,the consistency between Pentacam and the other two instruments decreases significantly.
基金supported by the Central Government Guidance Funds for Local Science and Technology Development Program(grant no.ZYYD2025ZY21)the Science and Technology Plan Project of the Xinjiang Production and Construction Corps(2023AB036)+1 种基金the Xinjiang Meteorological Bureau High-Level Key Talent Programthe Natural Science Foundation of the Xinjiang Uygur Autonomous Region(2023D01A17 and 2025D01A109).
文摘Low-visibility phenomena strongly impact the environment,as well as transportation,aviation and other fields that are closely related to people's livelihoods;thus,they represent important ecological issues of social concern.Based on observation data concerning low-visibility phenomena derived from 105 national meteorological stations in Xinjiang,China over the past 20 years,we systematically analyzed the differences between manual and instrument observations for six types of low-visibility phenomena,with a focus on exploring their spatiotemporal distribution characteristics using instrument data.The results revealed that low-visibility phenomena were dominated by fog-and haze-related events(mist,fog,and haze)in northern Xinjiang and dust-related events(dust storms,blowing sand,and floating dust)in southern Xinjiang,with transitional characteristics observed in eastern Xinjiang.Compared with manual observations,the instrument measurements significantly improved the fine-scale low-visibility phenomenon identification process.On the basis of the instrument observation data,spatial-dimension analysis results indicated that low-visibility phenomena in Xinjiang were significantly influenced by terrain factors.Constrained by the Tianshan Mountains,haze-like phenomena formed a core agglomeration area in northern Xinjiang,whereas dust-and sand-related phenomena radiated outward,with the Taklimakan Desert at the center.Moreover,the gripping effect of the terrain promoted dust transmission along low-altitude channels.Temporally,fog-and haze-related phenomena occurred mainly during autumn and winter,and the proportion of these events decreased from 76.7%to 55.1%.The fog-and haze-related phenomena demonstrated a U-shaped rebound trend,while the proportion of mist phenomena decreased by 34.2%.Dust storms occurred during spring,accounting for 23.3%to 44.9%of all storms.Instrument measurement technology has the advantages of high spatial and temporal resolutions and multiparameter coordination but provides a limited dust-haze mixed-pollution identification capacity.This study provides crucial reference data for enhancing the understanding of low-visibility events in Xinjiang and the potential responses while improving the accuracy of pollution source tracking and meteorological process diagnosis tasks.
基金supported by the Yunnan Revitalization Talent Support Program(202305AS350029 and 202305AT350005)Yunnan Revitalization Talent Support Program-Science&Technology Champion Project(202105AB160001)+1 种基金Yunnan Key Laboratory of Solar Physics and Space Science(202205AG070009)Yunnan Provincial Science and Technology Department(202401AU070062).
文摘The segmented solar telescope described in this study employs a simultaneous dual-wavelength measurement technique to achieve co-phase alignment.To meet the measurement requirements of a 20μm range,5 nm root mean square precision,and edge jump rates of<10^(−6),this study focused on calibrating the dual-wavelength measurement system for the segmented-mirror solar telescope.Analysis of the relative error in the measurement system revealed that assembly-induced errors such as defocus,translation,scaling,and rotation markedly degrade measurement accuracy.To address these issues,we propose a defocus error compensation algorithm,based on the light intensity distribution of the point spread function(PSF)and an affine transformation model,to calibrate spatial pose deviations across the two measurement channels.A dual-wavelength measurement system was implemented on a segmented-mirror experimental platform for calibration.Experimental results demonstrated that the mean relative error decreased from−0.6423 to−0.0345 nm after calibration,reflecting improved reliability and stability of the co-phase measurements.
基金the National Natural Science Foundation of China[62525301,62127811,62433019]the New Cornerstone Science Foundation through the XPLORER PRIZEthe financial support by the China Postdoctoral Science Foundation[GZB20240797].
文摘Single-cell biomechanics and electrophysiology measuring tools have transformed biological research over the last few decades,which enabling a comprehensive and nuanced understanding of cellular behavior and function.Despite their high-quality information content,these single-cell measuring techniques suffer from laborious manual processing by highly skilled workers and extremely low throughput(tens of cells per day).Recently,numerous researchers have automated the measurement of cell mechanical and electrical signals through robotic localization and control processes.While these efforts have demonstrated promising progress,critical challenges persist,including human dependency,learning complexity,in-situ measurement,and multidimensional signal acquisition.To identify key limitations and highlight emerging opportunities for innovation,in this review,we comprehensively summarize the key steps of robotic technologies in single-cell biomechanics and electrophysiology.We also discussed the prospects and challenges of robotics and automation in biological research.By bridging gaps between engineering,biology,and data science,this work aims to stimulate interdisciplinary research and accelerate the translation of robotic single-cell technologies into practical applications in the life sciences and medical fields.
文摘Transit managers can use Intelligent Transportation System technologies to access large amounts of data to monitor network status.However,the presentation of the data lacks structural information.Existing single-network description technologies are ineffective in representing the temporal and spatial characteristics simultaneously.Therefore,there is a need for complementary methods to address these deficiencies.To address these limitations,this paper proposes an approach that combines Network Snapshots and Temporal Paths for the scheduled system.A dual information network is constructed to assess the degree of operational deviation considering the planning tasks.To validate the effectiveness,discussions are conducted through a modified cosine similarity calculation on theoretical analysis,delay level description,and the ability to identify abnormal dates.Compared to some state-of-the-art methods,the proposed method achieves an average Spearman delay correlation of 0.847 and a relative distance of 3.477.Furthermore,case analyses are invested in regions of China's Mainland,Europe,and the United States,investigating both the overall and sub-regional network fluctuations.To represent the impact of network fluctuations in sub-regions,a response loss value was developed.The times that are prone to fluctuations are also discussed through the classification of time series data.The research can offer a novel approach to system monitoring,providing a research direction that utilizes individual data combined to represent macroscopic states.Our code will be released at https://github.com/daozhong/STPN.git.
文摘[Significance]In alignment with the national germplasm security strategy,current research efforts are accelerating the adoption of precision breeding in sheep.Within the whole-genome selection,accurate phenotyping of body morphometrics is critical for assessing growth performance and breeding value.Traditional manual measurements are inefficient,prone to human error,and may cause stress to sheep,limiting their suitability for precision sheep management.By summarizing the applications of sheep body size measurement technologies and analyzing their development directions,this paper provides theoretical references and practical guidance for the research and application of non contact sheep body size measurement.[Progress]This review synthesizes progress across three principal methodological paradigms:two-dimensional(2D)image-based techniques,three-dimensional(3D)point cloud-based approaches,and integrated 2D-3D fusion systems.2D methods,employing either handcrafted geometric features or deep learning-based keypoint detector algorithms,are cost-effective and operationally simple but sensitive to variation in imaging conditions and unable to capture critical circumference metrics.3D point-cloud approaches enable precise reconstruction of full animal morphology,supporting comprehensive body-size acquisition with higher accuracy,yet face challenges including high hardware costs,complex data workflows,and sensitivity to posture variability.Hybrid 2D-3D fusion systems combine semantic richness from RGB imagery with geometric completeness from point clouds.Having been effectively validated in other livestock specise,e.g.,cattle and pigs,these fusion systems have demonstrated excellent performance,providing important technical references and practical insights for sheep body size measurement.[Conclusions and Prospects]Firstly,future research should focus on constructing large-scale,high-quality datasets for sheep body size measurement that encompass diverse breeds,growth stages,and environmental conditions,thereby enhancing model robustness and generalization.Secondly,the development of lightweight artificial intelligence models is essential.Techniques such as model compression,quantization,and algorithmic optimization can substantially reduce computational complexity and storage requirements,facilitating deployment in resource-constrained environments.Thirdly,the 3D point cloud processing pipeline should be streamlined to improve the efficiency of data acquisition,filtering,registration,and segmentation,while promoting the integration of low-cost,high-resilience vision systems into practical farming scenarios.Fourthly,specific emphasis should be placed on improving the accuracy of curved-dimensional measurements,such as chest circumference,abdominal circumference,and shank circumference,through advances in pose standardization,refined 3D segmentation strategies,and multimodal data fusion.Finally,the cross-fertilization of sheep body size measurement technologies with analogous methods for other livestock species offers a promising pathway for mutual learning and collaborative innovation,accelerating the industrialization of automated sheep morphometric systems and supporting the development of intelligent,data-driven pasture management practices.
基金supported by the Bureau of Frontier Sciences and Basic Research,Chinese Academy of Sciences(Grant No.QYJ-2025-0103)the National Natural Science Foundation of China(Grant Nos.42441834,42241105,42441825,and 42203048)the Key Research Program of the Institute of Geology and Geophysics,Chinese Academy of Sciences(Grant No.IGGCAS-202401).
文摘As one of the major volatile components in extraterrestrial materials,nitrogen(N_(2))isotopes serve not only as tracers for the formation and evolution of the solar system,but also play a critical role in assessing planetary habitability and the search for extraterrestrial life.The integrated measurement of N_(2)and argon(Ar)isotopes by using noble gas mass spectrometry represents a state-of-the-art technique for such investigations.To support the growing demands of planetary science research in China,we have developed a high-efficiency,high-precision method for the integrated analysis of N_(2)and Ar isotopes.This was achieved by enhancing gas extraction and purification systems and integrating them with a static noble gas mass spectrometer.This method enables integrated N_(2)-Ar isotope measurements on submilligram samples,significantly improving sample utilization and reducing the impact of sample heterogeneity on volatile analysis.The system integrates CO_(2)laser heating,a modular two-stage Zr-Al getter pump,and a CuO furnace-based purification process,effectively reducing background levels(N_(2)blank as low as 0.35×10^(−6)cubic centimeters at standard temperature and pressure[ccSTP]).Analytical precision is ensured through calibration with atmospheric air and CO corrections.To validate the reliability of the method,we performed N_(2)-Ar isotope analyses on the Allende carbonaceous chondrite,one of the most extensively studied meteorites internationally.The measured N_(2)concentrations range from 19.2 to 29.8 ppm,withδ15N values between−44.8‰and−33.0‰.Concentrations of 40Ar,36Ar,and 38Ar are(12.5-21.1)×10^(−6)ccSTP/g,(90.9-150.3)×10^(−9)ccSTP/g,and(19.2-30.7)×10^(−9)ccSTP/g,respectively.These values correspond to cosmic-ray exposure ages of 4.5-5.7 Ma,consistent with previous reports.Step-heating experiments further reveal distinct release patterns of N and Ar isotopes,as well as their associations with specific mineral phases in the meteorite.In summary,the combined N_(2)-Ar isotopic system offers significant advantages for tracing volatile sources in extraterrestrial materials and will provide essential analytical support for upcoming Chinese planetary missions,such as Tianwen-2.
基金supported by the National Natural Science Foundation of China(Nos.12275321,12121005,12475129,and 12335009)the Natural Science Foundation of Guangdong Province,China(No.2025A1515012112)+6 种基金the International Atomic Energy Agency Coordinated Research Project F41034(No.28649)the computational resources from Sun Yat-sen University the National Supercomputer Center in Guangzhouthe Open Project of Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology(No.NLK2023-08)the Central Government Guidance Funds for Local Scientific and Technological Development,China(No.Guike ZY22096024)the Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030006)Young Scientists Fund of the National Natural Science Foundation of China(No.12405144)the National Key Research and Development Program(MOST 2022YFA1602304).
文摘A new multi-detector array named HALIMA(Hybrid Array for LIfetime MeAsurement)has been developed at Lanzhou for nuclear structure studies in fission.The array comprises eight BGO-shielded High-Purity Germanium detectors and twenty fast Ce-doped Lanthanum Bromide[LaBr_(3)(Ce)]detectors shielded with CsI(Tl).HALIMA is further complemented by two ancillary detector systems:fission fragment(FF)detectors and β detectors.This configuration enables precise sub-nanosecond lifetime measurements using the fourfold FF/β-Ge-LaBr_(3)(Ce)-LaBr_(3)(Ce)coincidence technique.The performance and specifications of the detectors,associated electronics,and the data acquisition system are presented in detail.The advantage of FF selectivity is emphasized,which significantly enhances sensitivity to specific fission channels.Using this approach,the lifetimes of the nuclear excited states populated in the spontaneous fission of^(252)Cf were measured,showing good agreement with the established literature values.
基金Shandong Provincial Education and Teaching Research Topic“Research on Student Value-Added Evaluation for Promoting Deep Learning”(2023JXY500)。
文摘As the enlightenment stage of students’Chinese learning,primary school Chinese education plays a key role in cultivating students’language ability,thinking development,and humanistic literacy.Value-added evaluation,as an evaluation method that focuses on the changes in students’individual development and attaches importance to the learning process,has gradually attracted attention in the application of primary school Chinese education.This paper first analyzes the problems existing in the current implementation of value-added evaluation in primary school Chinese,and then explores the countermeasures to improve the effectiveness of value-added evaluation in primary school Chinese from the aspects of evaluation concept,evaluation content,evaluation method,evaluation subject,and application of evaluation results.The purpose is to provide strong support for the improvement of primary school Chinese teaching quality and the all-round development of students.
基金Artificial Intelligence Education Research Project of Shandong Provincial Audio-Visual Education Center“Exploration of the Application of Large-scale AI Models in Student Value-added Evaluation from an Evidence-based Perspective”(SDDJ202501035)。
文摘Value-added evaluation focuses on individual student growth by tracking changes in academic performance,skills,literacy,etc.,at different time points.It weakens horizontal comparisons and emphasizes vertical progress to more fairly reflect educational effectiveness.This evaluation method is particularly suitable for vocational education,effectively motivating students’learning enthusiasm and enhancing their self-confidence.Foreign research is represented by the Tennessee Value-Added Assessment System(TVAAS),widely used in evaluating school quality and teacher performance.Domestic research currently focuses on the theoretical construction,model establishment,optimization,and practical application of value-added evaluation,still facing significant challenges in data collection comprehensiveness and model adaptability.Aiming at current issues,this study focuses on exploring the application of artificial intelligence large models in student value-added evaluation from an evidence-based perspective,committed to constructing an innovative evidence-based value-added evaluation system.It aims to achieve precise assessment of students’learning effect“net value-added”through multi-source data collection,intelligent analysis,and personalized feedback.The system integrates outcome evaluation,process evaluation,value-added evaluation,and comprehensive evaluation to form a“four-in-one”dynamic evaluation framework,considering students’starting points,process performance,and final achievements.In the future,value-added evaluation needs to further expand the assessment of non-academic dimensions(such as professional literacy and social-emotional skills)and explore the application of non-linear models to promote the deepening and innovation of educational evaluation reform.
基金This paper is the research result of“Research on Innovation of Evidence-Based Teaching Paradigm in Vocational Education under the Background of New Quality Productivity”(2024JXQ176)the Shandong Province Artificial Intelligence Education Research Project(SDDJ202501035),which explores the application of artificial intelligence big models in student value-added evaluation from an evidence-based perspective。
文摘Based on the educational evaluation reform,this study explores the construction of an evidence-based value-added evaluation system based on data-driven,aiming to solve the limitations of traditional evaluation methods.The research adopts the method of combining theoretical analysis and practical application,and designs the evidence-based value-added evaluation framework,which includes the core elements of a multi-source heterogeneous data acquisition and processing system,a value-added evaluation agent based on a large model,and an evaluation implementation and application mechanism.Through empirical research verification,the evaluation system has remarkable effects in improving learning participation,promoting ability development,and supporting teaching decision-making,and provides a theoretical reference and practical path for educational evaluation reform in the new era.The research shows that the evidence-based value-added evaluation system based on data-driven can reflect students’actual progress more fairly and objectively by accurately measuring the difference in starting point and development range of students,and provide strong support for the realization of high-quality education development.
文摘The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.
基金funded by the National Natural Science Foundation of China Instrumentation Program(52327806)Youth Fund of the National Nature Foundation of China(62405020)China Postdoctoral Science Foundation(2024M764131).
文摘Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predominantly on the phase-shifting approach,which involves collecting multiple interferograms and imposes stringent demands on environmental stability.These issues significantly hinder its ability to achieve real-time and dynamic high-precision measurements.Therefore,this study proposes a high-precision large-aperture single-frame interferometric surface profile measurement(LA-SFISPM)method based on deep learning and explores its capability to realize dynamic measurements with high accuracy.The interferogram is matched to the phase by training the data measured using the small aperture.The consistency of the surface features of the small and large apertures is enhanced via contrast learning and feature-distribution alignment.Hence,high-precision phase reconstruction of large-aperture optical components can be achieved without using a phase shifter.The experimental results show that for the tested mirror withΦ=820 mm,the surface profile obtained from LA-SFISPM is subtracted point-by-point from the ground truth,resulting in a maximum single-point error of 4.56 nm.Meanwhile,the peak-to-valley(PV)value is 0.0758λ,and the simple repeatability of root mean square(SR-RMS)value is 0.00025λ,which aligns well with the measured results obtained by ZYGO.In particular,a significant reduction in the measurement time(reduced by a factor of 48)is achieved compared with that of the traditional phase-shifting method.Our proposed method provides an efficient,rapid,and accurate method for obtaining the surface profiles of optical components with different diameters without employing a phase-shifting approach,which is highly desired in large-aperture interferometric measurement systems.
基金supported by the National Natural Science Foundation of China under Grant No.62271043Ministry of Education of China under Grant No.8091B032123Beijing Natural Science Foundation under Grant No.L212029。
文摘Radar cross section(RCS)plays a critical role in modeling target scattering characteristics and enhancing the precision of target detection and localization in integrated sensing and communication(ISAC)systems.This paper investigates the human body RCS at 26 GHz via multiangle channel measurements under different clothing conditions.Based on calibrated electromagnetic(EM)parameters,the RCS characteristics of the human body in far-field conditions are analyzed using ray-tracing(RT)simulations.Some suggestions for the design of ISAC systems are also discussed.The results provide a solid theoretical foundation and practical reference for the modeling of target scattering characteristics for ISAC channels.
基金the funding provided by the National Helicopter Development Project of China。
文摘Accurate measurement of helicopter rotor motion parameters(flap,lead-lag,torsion,and azimuth angles)is essential for rotor blade design,helicopter dynamics modeling,and flight safety and health monitoring.However,the existing methods face challenges in testing equipment installation,calibration,and data transmission,resulting in limited reports on real-time in-flight measurements of blade motion parameters.This paper proposes a non-contact optoelectronic method based on two-dimensional position-sensitive detectors for in-flight measurement and a ground calibration system to obtain real-time rotor motion parameters during helicopter flight.The proposed method establishes the time evolution relationship of rotor motion parameters and verifies the performance of the in-flight measurement system regarding measurement resolution and accuracy through the construction of a blade motion posture experimental platform.The proposed method has been applied to the flight measurement of a medium-sized single-rotor helicopter,and the obtained results have been compared with theoretical analysis outcomes.Furthermore,this paper examines the characteristics of blade motion parameters during flight and discusses the challenges and potential solutions for measuring rotor motion parameters during helicopter flight using the proposed method.
文摘Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel performance-based fault detection and identification(FDI)strategy for twin-shaft turbofan gas turbine engines and addresses these uncertainties through a first-order Takagi-Sugeno-Kang fuzzy inference system.To handle ambient condition changes,we use parameter correction to preprocess the raw measurement data,which reduces the FDI’s system complexity.Additionally,the power-level angle is set as a scheduling parameter to reduce the number of rules in the TSK-based FDI system.The data for designing,training,and testing the proposed FDI strategy are generated using a component-level turbofan engine model.The antecedent and consequent parameters of the TSK-based FDI system are optimized using the particle swarm optimization algorithm and ridge regression.A robust structure combining a specialized fuzzy inference system with the TSK-based FDI system is proposed to handle measurement biases.The performance of the first-order TSK-based FDI system and robust FDI structure are evaluated through comprehensive simulation studies.Comparative studies confirm the superior accuracy of the first-order TSK-based FDI system in fault detection,isolation,and identification.The robust structure demonstrates a 2%-8%improvement in the success rate index under relatively large measurement bias conditions,thereby indicating excellent robustness.Accuracy against significant bias values and computation time are also evaluated,suggesting that the proposed robust structure has desirable online performance.This study proposes a novel FDI strategy that effectively addresses measurement uncertainties.
