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
Accurate temperature measurement is a crucial step in predicting and managing the aerodynamic heating during Mars entry and Earth reentry.These processes often occur at extremely high temperatures and pose challenges ...Accurate temperature measurement is a crucial step in predicting and managing the aerodynamic heating during Mars entry and Earth reentry.These processes often occur at extremely high temperatures and pose challenges for quantitative measurements.A 1-μs time-resolved laser absorption technique was developed for simultaneous and time-dependent temperature and CO-concentration measurements over 3000-6000 K by adopting the P(0,21)and P(2,15)lines.To achieve quantitative measurement,the line strengths and Ar-broadening parameters were calibrated within 3030-5980 K.A“W”-shaped path-amplified strategy was used to increase the absorption features of the two lines during the calibration process.Validation experiments were conducted at 3040-5970 K to verify the accuracy of the technique.The new technique was then applied for simultaneous and time-resolved temperature and CO-concentration measurements during the CO_(2)dissociation process to further demonstrate the feasibility of the developed technique.The temperature-dependent CO_(2)absorption cross-sections at line centers of the two lines were calibrated within 2040-5870 K.The CO_(2)absorption interferences were quantified and subtracted from the measured laser absorbances.The measured results(referring to temperature and CO concentration)were generally consistent with the predictions from the kinetics mechanisms in the literature,highlighting the applicability of the developed technique for temperature measurements and CO_(2)dissociation studies within the investigated temperature range.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
Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stre...Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution method.The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth.There is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and messy.Moreover,there is no obvious relationship between the rock quality designation(RQD)and depth.The maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same depth.In addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data.展开更多
The accurate characterization of thermoelectric properties at low temperatures is crucial for the development of high-performance thermoelectric cooling devices. While measurement errors of thermoelectric properties a...The accurate characterization of thermoelectric properties at low temperatures is crucial for the development of high-performance thermoelectric cooling devices. While measurement errors of thermoelectric properties at temperatures above room temperature have been extensively discussed, there is a lack of standard measurement protocols and error analyses for low-temperature transport properties. In this study, we present a measurement system capable of characterizing all three key thermoelectric parameters, i.e., Seebeck coefficient, electrical conductivity, and thermal conductivity, for a single sample across a temperature range of 10 K to 300 K. We investigated six representative commercial Bi_(2)Te_(3)-based samples(three N-type and three P-type). Using an error propagation model, we systematically analyzed the measurement uncertainties of the three intrinsic parameters and the resulting thermoelectric figure of merit. Our findings reveal that measurement uncertainties for both N-type and P-type Bi_(2)Te_(3)-based materials can be effectively maintained below 5% in the temperature range of 40 K to 300 K. However, the uncertainties increase to over 10% at lower temperatures, primarily due to the relatively smaller values of electrical resistivity and Seebeck coefficients in this regime. This work establishes foundational data for Bi_(2)Te_(3)-based thermoelectric materials and provides a framework for broader investigations of advanced low-temperature thermoelectrics.展开更多
For the past few years,the prevalence of cardiovascular disease has been showing a year-on-year increase,with a death rate of 2/5.Coronary heart disease(CHD)rates have increased 41%since 1990,which is the number one d...For the past few years,the prevalence of cardiovascular disease has been showing a year-on-year increase,with a death rate of 2/5.Coronary heart disease(CHD)rates have increased 41%since 1990,which is the number one disease endangering human health in the world today.The risk indicators of CHD are complicated,so selecting effective methods to screen the risk characteristics can make the risk predictionmore efficient.In this paper,we present a comprehensive analysis ofCHDrisk indicators fromboth data and algorithmic levels,propose a method for CHDrisk indicator identification based on multi-angle integrated measurements and Sequential Backward Selection(SBS),and then build a risk prediction model.In the multi-angle integrated measurements stage,mRMR(Maximum Relevance Minimum Redundancy)is selected from the angle of feature correlation and redundancy of the dataset itself,SHAPRF(SHapley Additive exPlanations-Random Forest)is selected from the angle of interpretation of each feature to the results,and ARFS-RF(Algorithmic Randomness Feature Selection Random Forest)is selected from the angle of statistical interpretation of classification algorithm to measure the degree of feature importance.In the SBS stage,the features with low scores are deleted successively,and the accuracy of LightGBM(Light Gradient Boosting Machine)model is used as the evaluation index to select the final feature subset.This new risk assessment method is used to identify important factors affecting CHD,and the CHD dataset from the Kaggle website is used as the study subject.Finally,11 features are retained to construct a risk assessment indicator system for CHD.Using the LightGBM classifier as the core evaluationmetric,ourmethod achieved an accuracy of 0.8656 on the Kaggle CHD dataset(4238 samples,16 initial features),outperforming individual feature selection methods(mRMR,SHAP-RF,ARFS-RF)in both accuracy and feature reduction.This demonstrates the novelty and effectiveness of our multi-angle integrated measurement approach combined with SBS in building a concise yet highly predictive CHD risk model.展开更多
Using nine ice-tethered buoys deployed across the marginal ice zone(MIZ)and pack ice zone(PIZ)north of the Laptev Sea during the expedition of the Multidisciplinary drifting Observatory for the Study of Arctic Climate...Using nine ice-tethered buoys deployed across the marginal ice zone(MIZ)and pack ice zone(PIZ)north of the Laptev Sea during the expedition of the Multidisciplinary drifting Observatory for the Study of Arctic Climate(MOSAiC)in 2019-2020,we characterized the spatiotemporal variations in sea ice kinematics and deformation between October 2019 and July 2020 in the Transpolar Drift(TPD).From October to November,the buoys were in the upstream area of the TPD;spatial variations of deformation rates were significantly correlated with initial ice thickness(R=−0.84,P<0.05).From December 2019 to March 2020,the buoys were in the high Arctic and the ice cover was consolidated;heterogeneity in ice kinematics as measured across the buoys reduced by 65%.From April to May 2020,the buoys were in the downstream TPD;amplified spatial variations in ice kinematics were observed.This is because two buoys had drifted over the shallow waters north of Svalbard earlier;trajectory-stretching exponents derived from the data from these two buoys indicate deformation rates(10.6 d^(−1))that were about twice those in the deep basin(4.2 d^(−1)).By June 2020,a less consolidated ice pack and enhanced tidal forcing in the Fram Strait MIZ resulted in ice deformation with a semi-diurnal power spectral density of>0.25 d^(−1),which is about 1.5 times that in PIZ.Therefore,in both the upstream and downstream regions of the TPD,the transition between the MIZ and the PIZ contributes to the spatial and seasonal variations of sea ice motion and deformation.The results from this study can be used to support the characterization of the momentum balance and influencing factors during the ice advection along the TPD,which is a crucial corridor for Arctic sea ice outflow to the north Atlantic Ocean.展开更多
When discussing atomic nuclei,deformation is one of the most common topics.However,when we connect the concept of shape with high-precision experimental measurements,sometimes the explanation may not be as simple as w...When discussing atomic nuclei,deformation is one of the most common topics.However,when we connect the concept of shape with high-precision experimental measurements,sometimes the explanation may not be as simple as we think.A recent measurement of nuclear charge radii(Phys.Rev.Lett.134,182501(2025))challenges current nuclear ab initio models.展开更多
At the stage of preliminary scheme and algorithm design for spaceborne navigation systems, a precise and high-fidelity software global positioning system （GPS） simulator is a necessary and feasible testing facility ...At the stage of preliminary scheme and algorithm design for spaceborne navigation systems, a precise and high-fidelity software global positioning system （GPS） simulator is a necessary and feasible testing facility in laboratory environments, with consideration of the tradeoffs where possible. This article presents a software GPS measurements simulator on the L1 C/A code and carrier signal for space-oriented navigation system design. The simulator, coded in MATLAB language, generates both C/A code pseudorange and carrier phase measurements. Mathematical models in the Earth centered inertial （ECI） frame are formulated to simulate the GPS constellation and to generate GPS measurements. A series of efficient measures are investigated and utilized to rationalize the enhanced simulator, in terms of ephemeris data selection, space ionospheric model and range rate calculation, etc. Such an enhanced simulator has been facilitating our current work for designing a space integrated GPS/inertial navigation system （INS） navigation system. Consequently, it will promote our future research on space-oriented navigation system.展开更多
Noise is inevitable in electrical capacitance tomography(ECT)measurements.This paper describes the influence of noise on ECT performance for measuring gas-solids fluidized bed characteristics.The noise distribution is...Noise is inevitable in electrical capacitance tomography(ECT)measurements.This paper describes the influence of noise on ECT performance for measuring gas-solids fluidized bed characteristics.The noise distribution is approximated by the Gaussian distribution and added to experimental capacitance data with various intensities.The equivalent signal strength(Ф)that equals the signal-to-noise ratio of packed beds is used to evaluate noise levels.Results show that the Pearson correlation coefficient,which indicates the similarity of solids fraction distributions over pixels,increases with Ф,and reconstructed images are more deteriorated at lower Ф.Nevertheless,relative errors for average solids fraction and bubble size in each frame are less sensitive to noise,attributed to noise compromise caused by the process of pixel values.These findings provide useful guidance for assessing the accuracy of ECT measurements of multiphase flows.展开更多
A full-scale research study was conducted during the bored tunnelling of the Klang Valley Mass Rapid Transit-Putrajaya Line beneath an existing building structure in Kuala Lumpur,Malaysia.The primary objective was to ...A full-scale research study was conducted during the bored tunnelling of the Klang Valley Mass Rapid Transit-Putrajaya Line beneath an existing building structure in Kuala Lumpur,Malaysia.The primary objective was to investigate the tunnel-soil-pile interaction at various stages of tunnel excavation.This study combined field measurements and three-dimensional(3D)numerical analysis to understand the transient effects of TBM tunnelling on a loaded pile.An experimental pile was instrumented with vibrating wire strain gauges,an inclinometer,and distributed fibre optic sensors using Brillouin optical time domain analysis.The pile was pre-loaded and continuously monitored in real-time throughout the tunnel construction process.The 3D finite element modelling was used to simulate the pile’s transient responses based on actual tunnel boring machine(TBM)driving data.The study revealed that the zone of influence due to tunnelling effects extended from y¼2D to y¼4D,with the peak effect observed at y¼1D to 1.5D,where D represents the tunnel diameter.The analysis of axial load patterns highlighted transient responses,including tensile loads below the tunnel invert,which propagated upward and subsided due to negative skin friction.The maximum downdrag load observed reached 56%e71%of the pile’s working load.Additionally,pile movement patterns indicated outward deflections as the TBM approached and a return toward the tunnel post-passage,aligning with the predicted behaviour in a negative face loss scenario.This validated numerical framework provides a solid foundation for further parametric studies and enhances the understanding of tunnel-soil-pile interactions.展开更多
Aviation kerosene RP-3 is extensively used in China.This paper details the measurement of the density of Chinese aviation kerosene RP-3 employing the flow method under high-pressure and high-temperature conditions.The...Aviation kerosene RP-3 is extensively used in China.This paper details the measurement of the density of Chinese aviation kerosene RP-3 employing the flow method under high-pressure and high-temperature conditions.The methodology utilizes circular tubes with two different diameters.The density of aviation kerosene RP-3 was experimentally measured for the first time within a pressure range from 6 MPa to 8 MPa and a temperature range from 323 K to 783 K,with a maximum relative uncertainty of 0.35%.The experimental setup used n-decane for calibration,achieving an average calibration error of 0.91%.The data indicate that the density of RP-3 ranges from 764 kg/m^(3)to 247 kg/m^(3)under the tested conditions.The results show that the density of kerosene RP-3 decreases with an increase in temperature at a constant pressure,and at a given temperature,a higher pressure results in a higher density.Polynomial fitting was applied to the data,resulting in the average absolute deviation of 1.09%,0.80%,and 0.76%at different pressures of 6,7,and 8 MPa,respectively.展开更多
Ensuring highway safety relies heavily on pavement friction resistance.To enable network-level pavement skid resistance monitoring and management,this study proposes a non-contact three-dimensional laser surface testi...Ensuring highway safety relies heavily on pavement friction resistance.To enable network-level pavement skid resistance monitoring and management,this study proposes a non-contact three-dimensional laser surface testing method to obtain detailed aggregate surface data.The existing contact-based skid resistance measurement methods suffer from poor reproducibility and repeatability,hindering their application for network-level management.In this research,traditional multiple linear regression and four machine learning methods,support vector machine(SVM),random forest(RF),gradient boosting decision tree(GBDT),and convolutional neural network(CNN),are utilized to evaluate and predict pavement frictional performance.To assess the proposed methods,data from 45 pavement sites in Oklahoma,including 6 major preventive maintenance(PM)treatments and 7 typical types of aggregates,are collected.Parallel data acquisition is conducted at highway speeds using a grip tester and a high-speed texture profiler to measure pavement skid resistance and surface macro-texture,respectively.Aggregate properties are captured in 3D using a portable ultra-high-resolution 3D laser imaging scanner,leading to the calculation of four types of 3D aggregate parameters characterizing the micro-texture of aggregate surfaces.The relationship between pavement surface friction and texture is explored using machine learning models.The results reveal that the random forest and gradient boosting decision tree models exhibit the highest accuracy,SVM and CNN perform moderately,while the traditional linear regression method fares the worst.By assessing the importance of the 38 parameter variables,the most critical 21 variables were selected for model development.Test results demonstrate that the GBDT model exhibits the best predictive performance,with an explanatory capability of 87.4%for road friction performance.The findings demonstrate the feasibility of replacing contact-based pavement friction evaluation with non-contact texture measurements,offering promising prospects for a network-level pavement skid resistance monitoring and management system.展开更多
Branch angles are an important plant morphological trait affecting light interception within forest canopies.However,studies on branch angles have been limited due to the time-consuming nature of manual measurements u...Branch angles are an important plant morphological trait affecting light interception within forest canopies.However,studies on branch angles have been limited due to the time-consuming nature of manual measurements using a protractor.Terrestrial laser scanning(TLS),however,provides new opportunities to measure branch angles more efficiently.Despite this potential,studies validating branch angle measurements from TLS have been limited.Here,our aim is to evaluate both manual and automatic branch angle measurements of European beech from TLS data using traditional field-measurements with a protractor as a reference.We evaluated the accuracy of branch angle measurements based on four automated algorithms(aRchiQSM,TreeQSM,Laplacian,SemanticLaplacian)from TLS data.Additionally,we assessed different ways of manual branch angle measurements in the field.Our study was based on a dataset comprising 124 branch angles measured from six European beech in a European deciduous forest.Our results show that manual branch angle measurements from TLS data are in high agreement with the reference(root-mean-squared error,RMSE:[3.57°-4.18°],concordance correlation coefficient,CCC:[0.950.97])across different branch length positions.Automated algorithms also are in high agreement with the reference although RMSE is approximately twice as large compared to manual branch angle measurements from TLS(RMSE:[9.29°-10.55°],CCC:[0.830.86])with manual leaf points removal.When applying the automatic wood-leaf separation algorithm,the performance of the four methods declined significantly,with only approximately 20 branch angles successfully identified.Moreover,it is important to note that there is no influence of the measurement position(branch surface versus center)for branch angle measurements.However,for curved branches,the selection of branch measurement length significantly impacts the branch angle measurement.This study provides a comprehensive understanding of branch angle measurements in forests.We show that automated measurement methods based on TLS data of branch angles are a valuable tool to quantify branch angles at larger scales.展开更多
High-precision refractive index measurement has become a research hotspot in recent years.However,traditional refractive index measurement often adopts intensity detection,whose performance is restricted by the classi...High-precision refractive index measurement has become a research hotspot in recent years.However,traditional refractive index measurement often adopts intensity detection,whose performance is restricted by the classical detection limit and is thus hard to improve further.In order to break through this limitation,we propose a quantum-enhanced refractive index sensing scheme utilizing even-coherent-state sources in combination with parity detection.In this paper,we analyze the detection performance of the proposed system.Due to the inevitable photon loss in practical applications,the effects of photon loss on resolution and sensitivity are also investigated.Numerical results show that the resolution of the proposed strategy breaks through the Rayleigh limit and achieves super-resolving refractive index measurement.Relative to existing coherent-state schemes,our strategy leads to a twofold resolution improvement.Furthermore,the physical origins of the super-resolution are analyzed.展开更多
The distance distributions between two site-specifically anchored spin labels in a protein,measured by pulsed electron-electron double resonance(PELDOR or DEER),provide rich sources of structural and conformational re...The distance distributions between two site-specifically anchored spin labels in a protein,measured by pulsed electron-electron double resonance(PELDOR or DEER),provide rich sources of structural and conformational restraints on the proteins or their complexes.The rigid connection of the nitroxide spin label to the protein improves the accuracy and precision of distance measurement.We report a new spin labelling approach by formation of thioester bond between nitroxide(NO)spin label,NOAI(NO spin labels activated by acetylimidazole),and a protein thiol,and this spin labeling method has demonstrated high performance in DEER distance measurement on proteins.The results showed that NOAI has shorter connection to the protein ligation site than 2,2,5,5-tetramethyl-pyrroline-1-oxyl methanethiosulfonate(MTSL)and 3-maleimido-proxyl(M-Prox)in the respective protein conjugate and produces narrower distance distributions for the tested proteins including ubiquitin(Ub),immunoglobulin-binding b1 domain of streptococcal protein G(GB1),and second mitochondria-derived activator of caspases(Smac).The NOAI protein conjugate connected by a thioester bond is resistant to reducing reagent and offers highfidelity DEER distance measurements in cell lysates.展开更多
This study developed a digital twin(DT)and structural health monitoring(SHM)system for a balanced cantilever bridge,utilizing advanced measurement techniques to enhance accuracy.Vibration and dynamic strain measuremen...This study developed a digital twin(DT)and structural health monitoring(SHM)system for a balanced cantilever bridge,utilizing advanced measurement techniques to enhance accuracy.Vibration and dynamic strain measurements were obtained using accelerometers and piezo-resistive strain gauges,capturing low-magnitude dynamic strains during operational vibrations.3D-LiDAR scanning and Ultrasonic Pulse Velocity(UPV)tests captured the bridge's as-is geometry and modulus of elasticity.The resulting detailed 3D point cloud model revealed the structure's true state and highlighted discrepancies between the as-designed and as-built conditions.Dynamic properties,including modal frequencies and shapes,were extracted from the strain and acceleration measurements,providing critical insights into the bridge's structural behavior.The neutral axis depth,indicating stress distribution and potential damage,was accurately determined.Good agreement between vibration measurement data and the as-is model results validated the reliability of the digital twin model.Dynamic strain patterns and neutral axis parameters showed strong correlation with model predictions,serving as sensitive indicators of local damage.The baseline digital twin model and measurement results establish a foundation for future bridge inspections and investigations.This study demonstrates the effectiveness of combining digital twin technology with field measurements for real-time monitoring and predictive maintenance,ensuring the sustainability and safety of the bridge infrastructure,thereby enhancing its overall resilience to operational and environmental stressors.展开更多
Schottky mass spectrometry utilizing heavy-ion storage rings is a powerful technique for the precise mass and decay half-life measurements of highly charged ions.Owing to the nondestructive ion detection features of S...Schottky mass spectrometry utilizing heavy-ion storage rings is a powerful technique for the precise mass and decay half-life measurements of highly charged ions.Owing to the nondestructive ion detection features of Schottky noise detectors,the number of stored ions in the ring is determined by the peak area in the measured revolution frequency spectrum.Because of their intrinsic amplitude-frequency characteristic(AFC),Schottky detector systems exhibit varying sensitivities at different frequencies.Using low-energy electron-cooled stored ions,a new method is developed to calibrate the AFC curve of the Schottky detector system of the Experimental Cooler Storage Ring(CSRe)storage ring located in Lanzhou,China.Using the amplitude-calibrated frequency spectrum,a notable refinement was observed in the precision of both the peak position and peak area.As a result,the storage lifetimes of the electron-cooled fully ionized^(56)Fe^(26+)ions were determined with high precision at beam energies of 13.7 and 116.4 MeV/u,despite of frequency drifts during the experiment.When electron cooling was turned off,the effective vacuum condition experienced by the 116.4 MeV/u^(56)Fe^(26+)ions was determined using amplitude-calibrated spectra,revealing a value of 2×10^(−10)mbar,which is consistent with vacuum gauge readings along the CSRe ring.The method reported herein will be adapted for the next-generation storage ring of the HIAF facility under construction in Huizhou,China.It can also be adapted to other storage ring facilities worldwide to improve precision and enhance lifetime measurements using many ions in the ring.展开更多
Developments of the micro-Gal level gravimeter based on atom interferometry are reviewed, and the recent progress and results of our group are also presented. Atom interferometric gravimeters have shown high resolutio...Developments of the micro-Gal level gravimeter based on atom interferometry are reviewed, and the recent progress and results of our group are also presented. Atom interferometric gravimeters have shown high resolution and accuracy for gravity measurements. This kind of quantum sensor has excited world-wide interest for both practical applications and fundamental research.展开更多
Metabolic dysfunction-associated steatotic liver disease(MASLD)is the most widespread chronic liver disease signified by serious life-threatening conditions.The prevalence of MASLD increases along the growing prevalen...Metabolic dysfunction-associated steatotic liver disease(MASLD)is the most widespread chronic liver disease signified by serious life-threatening conditions.The prevalence of MASLD increases along the growing prevalence in obesity and metabolic syndrome.To minimize costs and complications,non-invasive diagnostic tools,including transient elastography(TE),were introduced for assessment of MASLD.TE measures liver stiffness(LS),a clinical marker for the diagnosis of liver fibrosis and cirrhosis.LS measurements are based on ultrasound wave imaging and quantification.Vibration-controlled TE,including FibroScan®,is commonly used TE methods which can accurately identify the degree of liver fibrosis and cirrhosis progression.TE was reported to predict the progression towards hepatocellular carcinoma,portal hypertension,and varices.However,the accuracy of LS diagnostics alone in patients with MASLD remains controversial.TE measurements have several limitations,including inadequate precision due to focal liver lesions,cholestasis,inflammation,and other pathological and anatomical factors which can lead to the stiffness variability.Overestimations of TE readings were reported in obese patients with body mass index(BMI)over 30 kg/m2,and older patients with ascites,diabetes,or hypertension.Not all MASLD patients have high BMI.The prevalence of obesity among MASLD patients varies worldwide,indicating the urgent need for comprehensive diagnostic tools.In patients with MASLD,improved diagnostic accuracy has been demonstrated by combining LS measurements with other blood test-based scores and simple clinical parameters(agile scores based on age,sex,platelet count,aminotransferases,and diabetes).This study reviews the limitations of TE-based diagnostics and discusses the combined scoring algorithm.In conclusion,the sequence of LS measurements along assessment of other important clinical markers is an effective,low-cost,reliable tool to identify and monitor fibrosis progression in MASLD.展开更多
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 Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0620201)the frontier scientific research program of Deep Space Exploration Laboratory(Grant No.2022-QYKYJH-HXYF-019)the National Natural Science Foundation of China(Grant Nos.12388101,12027801,12402274,and U2430202)。
文摘Accurate temperature measurement is a crucial step in predicting and managing the aerodynamic heating during Mars entry and Earth reentry.These processes often occur at extremely high temperatures and pose challenges for quantitative measurements.A 1-μs time-resolved laser absorption technique was developed for simultaneous and time-dependent temperature and CO-concentration measurements over 3000-6000 K by adopting the P(0,21)and P(2,15)lines.To achieve quantitative measurement,the line strengths and Ar-broadening parameters were calibrated within 3030-5980 K.A“W”-shaped path-amplified strategy was used to increase the absorption features of the two lines during the calibration process.Validation experiments were conducted at 3040-5970 K to verify the accuracy of the technique.The new technique was then applied for simultaneous and time-resolved temperature and CO-concentration measurements during the CO_(2)dissociation process to further demonstrate the feasibility of the developed technique.The temperature-dependent CO_(2)absorption cross-sections at line centers of the two lines were calibrated within 2040-5870 K.The CO_(2)absorption interferences were quantified and subtracted from the measured laser absorbances.The measured results(referring to temperature and CO concentration)were generally consistent with the predictions from the kinetics mechanisms in the literature,highlighting the applicability of the developed technique for temperature measurements and CO_(2)dissociation studies within the investigated temperature range.
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financially supported by the National Natural Science Foundation of China(No.52204084)the Open Research Fund of the State Key Laboratory of Coal Resources and safe Mining,CUMT,China(No.SKLCRSM 23KF004)+3 种基金the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities),China(No.FRF-IDRY-GD22-002)the Fundamental Research Funds for the Central Universities and the Youth Teacher International Exchange and Growth Program,China(No.QNXM20220009)the National Key R&D Program of China(Nos.2022YFC2905600 and 2022 YFC3004601)the Science,Technology&Innovation Project of Xiongan New Area,China(No.2023XAGG0061)。
文摘Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution method.The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth.There is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and messy.Moreover,there is no obvious relationship between the rock quality designation(RQD)and depth.The maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same depth.In addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data.
基金supported by the National Natural Science Foundation of China (Grant No. 52172259)the National Key Research and Development Program of China (Grant Nos. 2021YFA0718700 and 2022YFB3803900)the Fundamental Research Funds for the Inner Mongolia Normal University (Grant No. 2022JBTD008)。
文摘The accurate characterization of thermoelectric properties at low temperatures is crucial for the development of high-performance thermoelectric cooling devices. While measurement errors of thermoelectric properties at temperatures above room temperature have been extensively discussed, there is a lack of standard measurement protocols and error analyses for low-temperature transport properties. In this study, we present a measurement system capable of characterizing all three key thermoelectric parameters, i.e., Seebeck coefficient, electrical conductivity, and thermal conductivity, for a single sample across a temperature range of 10 K to 300 K. We investigated six representative commercial Bi_(2)Te_(3)-based samples(three N-type and three P-type). Using an error propagation model, we systematically analyzed the measurement uncertainties of the three intrinsic parameters and the resulting thermoelectric figure of merit. Our findings reveal that measurement uncertainties for both N-type and P-type Bi_(2)Te_(3)-based materials can be effectively maintained below 5% in the temperature range of 40 K to 300 K. However, the uncertainties increase to over 10% at lower temperatures, primarily due to the relatively smaller values of electrical resistivity and Seebeck coefficients in this regime. This work establishes foundational data for Bi_(2)Te_(3)-based thermoelectric materials and provides a framework for broader investigations of advanced low-temperature thermoelectrics.
基金supported by the National Natural Science Foundation of China(No.72071150)the Fujian Provincial Natural Science Foundation of China(Nos.2024J01903,2025J01393).
文摘For the past few years,the prevalence of cardiovascular disease has been showing a year-on-year increase,with a death rate of 2/5.Coronary heart disease(CHD)rates have increased 41%since 1990,which is the number one disease endangering human health in the world today.The risk indicators of CHD are complicated,so selecting effective methods to screen the risk characteristics can make the risk predictionmore efficient.In this paper,we present a comprehensive analysis ofCHDrisk indicators fromboth data and algorithmic levels,propose a method for CHDrisk indicator identification based on multi-angle integrated measurements and Sequential Backward Selection(SBS),and then build a risk prediction model.In the multi-angle integrated measurements stage,mRMR(Maximum Relevance Minimum Redundancy)is selected from the angle of feature correlation and redundancy of the dataset itself,SHAPRF(SHapley Additive exPlanations-Random Forest)is selected from the angle of interpretation of each feature to the results,and ARFS-RF(Algorithmic Randomness Feature Selection Random Forest)is selected from the angle of statistical interpretation of classification algorithm to measure the degree of feature importance.In the SBS stage,the features with low scores are deleted successively,and the accuracy of LightGBM(Light Gradient Boosting Machine)model is used as the evaluation index to select the final feature subset.This new risk assessment method is used to identify important factors affecting CHD,and the CHD dataset from the Kaggle website is used as the study subject.Finally,11 features are retained to construct a risk assessment indicator system for CHD.Using the LightGBM classifier as the core evaluationmetric,ourmethod achieved an accuracy of 0.8656 on the Kaggle CHD dataset(4238 samples,16 initial features),outperforming individual feature selection methods(mRMR,SHAP-RF,ARFS-RF)in both accuracy and feature reduction.This demonstrates the novelty and effectiveness of our multi-angle integrated measurement approach combined with SBS in building a concise yet highly predictive CHD risk model.
基金supported by the National Key Research and Development Program of China(Grant no.2021YFC2803304)the National Natural Science Foundation of China(Grant nos.52192691 and 52192690)the Program of Shanghai Academic/Technology Research Leader(Grant no.22XD1403600).
文摘Using nine ice-tethered buoys deployed across the marginal ice zone(MIZ)and pack ice zone(PIZ)north of the Laptev Sea during the expedition of the Multidisciplinary drifting Observatory for the Study of Arctic Climate(MOSAiC)in 2019-2020,we characterized the spatiotemporal variations in sea ice kinematics and deformation between October 2019 and July 2020 in the Transpolar Drift(TPD).From October to November,the buoys were in the upstream area of the TPD;spatial variations of deformation rates were significantly correlated with initial ice thickness(R=−0.84,P<0.05).From December 2019 to March 2020,the buoys were in the high Arctic and the ice cover was consolidated;heterogeneity in ice kinematics as measured across the buoys reduced by 65%.From April to May 2020,the buoys were in the downstream TPD;amplified spatial variations in ice kinematics were observed.This is because two buoys had drifted over the shallow waters north of Svalbard earlier;trajectory-stretching exponents derived from the data from these two buoys indicate deformation rates(10.6 d^(−1))that were about twice those in the deep basin(4.2 d^(−1)).By June 2020,a less consolidated ice pack and enhanced tidal forcing in the Fram Strait MIZ resulted in ice deformation with a semi-diurnal power spectral density of>0.25 d^(−1),which is about 1.5 times that in PIZ.Therefore,in both the upstream and downstream regions of the TPD,the transition between the MIZ and the PIZ contributes to the spatial and seasonal variations of sea ice motion and deformation.The results from this study can be used to support the characterization of the momentum balance and influencing factors during the ice advection along the TPD,which is a crucial corridor for Arctic sea ice outflow to the north Atlantic Ocean.
基金supported by the National Natural Science Foundation of China(No.12235003).
文摘When discussing atomic nuclei,deformation is one of the most common topics.However,when we connect the concept of shape with high-precision experimental measurements,sometimes the explanation may not be as simple as we think.A recent measurement of nuclear charge radii(Phys.Rev.Lett.134,182501(2025))challenges current nuclear ab initio models.
基金Research Fund of Shanghai Academy of Spaceflight Technology
文摘At the stage of preliminary scheme and algorithm design for spaceborne navigation systems, a precise and high-fidelity software global positioning system （GPS） simulator is a necessary and feasible testing facility in laboratory environments, with consideration of the tradeoffs where possible. This article presents a software GPS measurements simulator on the L1 C/A code and carrier signal for space-oriented navigation system design. The simulator, coded in MATLAB language, generates both C/A code pseudorange and carrier phase measurements. Mathematical models in the Earth centered inertial （ECI） frame are formulated to simulate the GPS constellation and to generate GPS measurements. A series of efficient measures are investigated and utilized to rationalize the enhanced simulator, in terms of ephemeris data selection, space ionospheric model and range rate calculation, etc. Such an enhanced simulator has been facilitating our current work for designing a space integrated GPS/inertial navigation system （INS） navigation system. Consequently, it will promote our future research on space-oriented navigation system.
基金National Key Research and Development Program of China(2021YFA1501302)the National Natural Science Foundation of China(22121004,22122808)+1 种基金the Haihe Laboratory of Sustainable Chemical Transformations and the Program of Introducing Talents of Discipline to Universities(BP0618007)for financial supportsupported by the XPLORER PRIZE.
文摘Noise is inevitable in electrical capacitance tomography(ECT)measurements.This paper describes the influence of noise on ECT performance for measuring gas-solids fluidized bed characteristics.The noise distribution is approximated by the Gaussian distribution and added to experimental capacitance data with various intensities.The equivalent signal strength(Ф)that equals the signal-to-noise ratio of packed beds is used to evaluate noise levels.Results show that the Pearson correlation coefficient,which indicates the similarity of solids fraction distributions over pixels,increases with Ф,and reconstructed images are more deteriorated at lower Ф.Nevertheless,relative errors for average solids fraction and bubble size in each frame are less sensitive to noise,attributed to noise compromise caused by the process of pixel values.These findings provide useful guidance for assessing the accuracy of ECT measurements of multiphase flows.
文摘A full-scale research study was conducted during the bored tunnelling of the Klang Valley Mass Rapid Transit-Putrajaya Line beneath an existing building structure in Kuala Lumpur,Malaysia.The primary objective was to investigate the tunnel-soil-pile interaction at various stages of tunnel excavation.This study combined field measurements and three-dimensional(3D)numerical analysis to understand the transient effects of TBM tunnelling on a loaded pile.An experimental pile was instrumented with vibrating wire strain gauges,an inclinometer,and distributed fibre optic sensors using Brillouin optical time domain analysis.The pile was pre-loaded and continuously monitored in real-time throughout the tunnel construction process.The 3D finite element modelling was used to simulate the pile’s transient responses based on actual tunnel boring machine(TBM)driving data.The study revealed that the zone of influence due to tunnelling effects extended from y¼2D to y¼4D,with the peak effect observed at y¼1D to 1.5D,where D represents the tunnel diameter.The analysis of axial load patterns highlighted transient responses,including tensile loads below the tunnel invert,which propagated upward and subsided due to negative skin friction.The maximum downdrag load observed reached 56%e71%of the pile’s working load.Additionally,pile movement patterns indicated outward deflections as the TBM approached and a return toward the tunnel post-passage,aligning with the predicted behaviour in a negative face loss scenario.This validated numerical framework provides a solid foundation for further parametric studies and enhances the understanding of tunnel-soil-pile interactions.
基金supported by the Science Center for Gas Turbine Project,China(No.P2022-C-II-005-001)。
文摘Aviation kerosene RP-3 is extensively used in China.This paper details the measurement of the density of Chinese aviation kerosene RP-3 employing the flow method under high-pressure and high-temperature conditions.The methodology utilizes circular tubes with two different diameters.The density of aviation kerosene RP-3 was experimentally measured for the first time within a pressure range from 6 MPa to 8 MPa and a temperature range from 323 K to 783 K,with a maximum relative uncertainty of 0.35%.The experimental setup used n-decane for calibration,achieving an average calibration error of 0.91%.The data indicate that the density of RP-3 ranges from 764 kg/m^(3)to 247 kg/m^(3)under the tested conditions.The results show that the density of kerosene RP-3 decreases with an increase in temperature at a constant pressure,and at a given temperature,a higher pressure results in a higher density.Polynomial fitting was applied to the data,resulting in the average absolute deviation of 1.09%,0.80%,and 0.76%at different pressures of 6,7,and 8 MPa,respectively.
基金study is under the research project“development of aggregate characteristics-based preventive maintenance treatments using 3D laser imaging and aggregate imaging technology for optimized skid resistance of pavements”sponsored by the Oklahoma Department of Transportation(ODOT SPR 2275).
文摘Ensuring highway safety relies heavily on pavement friction resistance.To enable network-level pavement skid resistance monitoring and management,this study proposes a non-contact three-dimensional laser surface testing method to obtain detailed aggregate surface data.The existing contact-based skid resistance measurement methods suffer from poor reproducibility and repeatability,hindering their application for network-level management.In this research,traditional multiple linear regression and four machine learning methods,support vector machine(SVM),random forest(RF),gradient boosting decision tree(GBDT),and convolutional neural network(CNN),are utilized to evaluate and predict pavement frictional performance.To assess the proposed methods,data from 45 pavement sites in Oklahoma,including 6 major preventive maintenance(PM)treatments and 7 typical types of aggregates,are collected.Parallel data acquisition is conducted at highway speeds using a grip tester and a high-speed texture profiler to measure pavement skid resistance and surface macro-texture,respectively.Aggregate properties are captured in 3D using a portable ultra-high-resolution 3D laser imaging scanner,leading to the calculation of four types of 3D aggregate parameters characterizing the micro-texture of aggregate surfaces.The relationship between pavement surface friction and texture is explored using machine learning models.The results reveal that the random forest and gradient boosting decision tree models exhibit the highest accuracy,SVM and CNN perform moderately,while the traditional linear regression method fares the worst.By assessing the importance of the 38 parameter variables,the most critical 21 variables were selected for model development.Test results demonstrate that the GBDT model exhibits the best predictive performance,with an explanatory capability of 87.4%for road friction performance.The findings demonstrate the feasibility of replacing contact-based pavement friction evaluation with non-contact texture measurements,offering promising prospects for a network-level pavement skid resistance monitoring and management system.
基金supported by the Chinese Scholarship Council under Grant 202106910006.
文摘Branch angles are an important plant morphological trait affecting light interception within forest canopies.However,studies on branch angles have been limited due to the time-consuming nature of manual measurements using a protractor.Terrestrial laser scanning(TLS),however,provides new opportunities to measure branch angles more efficiently.Despite this potential,studies validating branch angle measurements from TLS have been limited.Here,our aim is to evaluate both manual and automatic branch angle measurements of European beech from TLS data using traditional field-measurements with a protractor as a reference.We evaluated the accuracy of branch angle measurements based on four automated algorithms(aRchiQSM,TreeQSM,Laplacian,SemanticLaplacian)from TLS data.Additionally,we assessed different ways of manual branch angle measurements in the field.Our study was based on a dataset comprising 124 branch angles measured from six European beech in a European deciduous forest.Our results show that manual branch angle measurements from TLS data are in high agreement with the reference(root-mean-squared error,RMSE:[3.57°-4.18°],concordance correlation coefficient,CCC:[0.950.97])across different branch length positions.Automated algorithms also are in high agreement with the reference although RMSE is approximately twice as large compared to manual branch angle measurements from TLS(RMSE:[9.29°-10.55°],CCC:[0.830.86])with manual leaf points removal.When applying the automatic wood-leaf separation algorithm,the performance of the four methods declined significantly,with only approximately 20 branch angles successfully identified.Moreover,it is important to note that there is no influence of the measurement position(branch surface versus center)for branch angle measurements.However,for curved branches,the selection of branch measurement length significantly impacts the branch angle measurement.This study provides a comprehensive understanding of branch angle measurements in forests.We show that automated measurement methods based on TLS data of branch angles are a valuable tool to quantify branch angles at larger scales.
文摘High-precision refractive index measurement has become a research hotspot in recent years.However,traditional refractive index measurement often adopts intensity detection,whose performance is restricted by the classical detection limit and is thus hard to improve further.In order to break through this limitation,we propose a quantum-enhanced refractive index sensing scheme utilizing even-coherent-state sources in combination with parity detection.In this paper,we analyze the detection performance of the proposed system.Due to the inevitable photon loss in practical applications,the effects of photon loss on resolution and sensitivity are also investigated.Numerical results show that the resolution of the proposed strategy breaks through the Rayleigh limit and achieves super-resolving refractive index measurement.Relative to existing coherent-state schemes,our strategy leads to a twofold resolution improvement.Furthermore,the physical origins of the super-resolution are analyzed.
基金supported by National Natural Science Foundation of China(22161142018,21991081,22177056,and 22174074)the Ministry of Science and Technology of China(2021YFA1600304).
文摘The distance distributions between two site-specifically anchored spin labels in a protein,measured by pulsed electron-electron double resonance(PELDOR or DEER),provide rich sources of structural and conformational restraints on the proteins or their complexes.The rigid connection of the nitroxide spin label to the protein improves the accuracy and precision of distance measurement.We report a new spin labelling approach by formation of thioester bond between nitroxide(NO)spin label,NOAI(NO spin labels activated by acetylimidazole),and a protein thiol,and this spin labeling method has demonstrated high performance in DEER distance measurement on proteins.The results showed that NOAI has shorter connection to the protein ligation site than 2,2,5,5-tetramethyl-pyrroline-1-oxyl methanethiosulfonate(MTSL)and 3-maleimido-proxyl(M-Prox)in the respective protein conjugate and produces narrower distance distributions for the tested proteins including ubiquitin(Ub),immunoglobulin-binding b1 domain of streptococcal protein G(GB1),and second mitochondria-derived activator of caspases(Smac).The NOAI protein conjugate connected by a thioester bond is resistant to reducing reagent and offers highfidelity DEER distance measurements in cell lysates.
基金funded by the Thailand Science Research and Innovation Fund,Chulalongkorn University(BCG_FF_68_165_2100_027)The first author(Tidarut Jirawattanasomkul)also gratefully acknowledges support from the Grants for Development of New Faculty Staff,Ratchadaphiseksomphot Fund,Chulalongkorn University.The corresponding author(Supasit Srivaranun)acknowledges the Research and Innovation Funding from National Research Council of Thailand(No.N84A680208)+2 种基金the Research Grant from Faculty of Engineering,Kasetsart University(No.67/05/CE)The fourth author(Suched Likitlersuang)acknowledges Thailand Science Research and Innovation Fund Chulalongkorn University(DISF68210001)the National Research Council of Thailand(NRCT):Grant No.N42A670572.
文摘This study developed a digital twin(DT)and structural health monitoring(SHM)system for a balanced cantilever bridge,utilizing advanced measurement techniques to enhance accuracy.Vibration and dynamic strain measurements were obtained using accelerometers and piezo-resistive strain gauges,capturing low-magnitude dynamic strains during operational vibrations.3D-LiDAR scanning and Ultrasonic Pulse Velocity(UPV)tests captured the bridge's as-is geometry and modulus of elasticity.The resulting detailed 3D point cloud model revealed the structure's true state and highlighted discrepancies between the as-designed and as-built conditions.Dynamic properties,including modal frequencies and shapes,were extracted from the strain and acceleration measurements,providing critical insights into the bridge's structural behavior.The neutral axis depth,indicating stress distribution and potential damage,was accurately determined.Good agreement between vibration measurement data and the as-is model results validated the reliability of the digital twin model.Dynamic strain patterns and neutral axis parameters showed strong correlation with model predictions,serving as sensitive indicators of local damage.The baseline digital twin model and measurement results establish a foundation for future bridge inspections and investigations.This study demonstrates the effectiveness of combining digital twin technology with field measurements for real-time monitoring and predictive maintenance,ensuring the sustainability and safety of the bridge infrastructure,thereby enhancing its overall resilience to operational and environmental stressors.
基金supported by the National Key R&D Program of China (No. 2023YFA1606401 and 2018YFA0404401)the Young Scholar of Regional Development,CAS ([2023] 15)+1 种基金Chinese Academy of Sciences Stable Support for Young Teams in Basic Research (No. YSBR-002)Special Fund for Strategic Pilot Technology of Chinese Academy of Sciences (No. XDB34000000)
文摘Schottky mass spectrometry utilizing heavy-ion storage rings is a powerful technique for the precise mass and decay half-life measurements of highly charged ions.Owing to the nondestructive ion detection features of Schottky noise detectors,the number of stored ions in the ring is determined by the peak area in the measured revolution frequency spectrum.Because of their intrinsic amplitude-frequency characteristic(AFC),Schottky detector systems exhibit varying sensitivities at different frequencies.Using low-energy electron-cooled stored ions,a new method is developed to calibrate the AFC curve of the Schottky detector system of the Experimental Cooler Storage Ring(CSRe)storage ring located in Lanzhou,China.Using the amplitude-calibrated frequency spectrum,a notable refinement was observed in the precision of both the peak position and peak area.As a result,the storage lifetimes of the electron-cooled fully ionized^(56)Fe^(26+)ions were determined with high precision at beam energies of 13.7 and 116.4 MeV/u,despite of frequency drifts during the experiment.When electron cooling was turned off,the effective vacuum condition experienced by the 116.4 MeV/u^(56)Fe^(26+)ions was determined using amplitude-calibrated spectra,revealing a value of 2×10^(−10)mbar,which is consistent with vacuum gauge readings along the CSRe ring.The method reported herein will be adapted for the next-generation storage ring of the HIAF facility under construction in Huizhou,China.It can also be adapted to other storage ring facilities worldwide to improve precision and enhance lifetime measurements using many ions in the ring.
基金supported by the National Natural Science Foundation of China(Grant Nos.41127002,11204094,11205064,and 11474115)the National High Technology Research and Development Program of China(Grant No.2011AA060503)
文摘Developments of the micro-Gal level gravimeter based on atom interferometry are reviewed, and the recent progress and results of our group are also presented. Atom interferometric gravimeters have shown high resolution and accuracy for gravity measurements. This kind of quantum sensor has excited world-wide interest for both practical applications and fundamental research.
文摘Metabolic dysfunction-associated steatotic liver disease(MASLD)is the most widespread chronic liver disease signified by serious life-threatening conditions.The prevalence of MASLD increases along the growing prevalence in obesity and metabolic syndrome.To minimize costs and complications,non-invasive diagnostic tools,including transient elastography(TE),were introduced for assessment of MASLD.TE measures liver stiffness(LS),a clinical marker for the diagnosis of liver fibrosis and cirrhosis.LS measurements are based on ultrasound wave imaging and quantification.Vibration-controlled TE,including FibroScan®,is commonly used TE methods which can accurately identify the degree of liver fibrosis and cirrhosis progression.TE was reported to predict the progression towards hepatocellular carcinoma,portal hypertension,and varices.However,the accuracy of LS diagnostics alone in patients with MASLD remains controversial.TE measurements have several limitations,including inadequate precision due to focal liver lesions,cholestasis,inflammation,and other pathological and anatomical factors which can lead to the stiffness variability.Overestimations of TE readings were reported in obese patients with body mass index(BMI)over 30 kg/m2,and older patients with ascites,diabetes,or hypertension.Not all MASLD patients have high BMI.The prevalence of obesity among MASLD patients varies worldwide,indicating the urgent need for comprehensive diagnostic tools.In patients with MASLD,improved diagnostic accuracy has been demonstrated by combining LS measurements with other blood test-based scores and simple clinical parameters(agile scores based on age,sex,platelet count,aminotransferases,and diabetes).This study reviews the limitations of TE-based diagnostics and discusses the combined scoring algorithm.In conclusion,the sequence of LS measurements along assessment of other important clinical markers is an effective,low-cost,reliable tool to identify and monitor fibrosis progression in MASLD.
