The correction for antenna phase center is considered in processing Global Positioning System （GPS） data collected from a network of GPS ultra-short baselines. Compared with the leveling measurements, the GPS result...The correction for antenna phase center is considered in processing Global Positioning System （GPS） data collected from a network of GPS ultra-short baselines. Compared with the leveling measurements, the GPS results show that the relative vertical offsets for the pairs of GPS receiver antenna phase centers still exist, although absolute calibration of the antenna phase center variations （PCVs） has been considered. With respect to the TPS CR.G3 antenna, the relative vertical offset for the LEI AT504 antenna is 8.4 mm, the offset for the ASH701945C_M antenna is 5.5 mm, and those for the ASHY00936E_C and ASH701945B_M antennas are approximately between 2 mm and -3 mm. The relative offsets for the same type of antennas are approximately 1 mm. By correcting the absolute PCVs, the existing relative offset becomes negligible for horizontal positioning.展开更多
On the basis of harmonic mapping theory,a mobile grid technology is applied to computational fluid dynamics(CFD).Starting from the observation that standard fixed-grid techniques often fail in addressing problems with...On the basis of harmonic mapping theory,a mobile grid technology is applied to computational fluid dynamics(CFD).Starting from the observation that standard fixed-grid techniques often fail in addressing problems with large deformations,we elaborate a new algorithm relying on the software COMSOL Multiphysics 5.3a to solve the coupling of the mobile grid equation and the governing differential equations for fluid flow.The motion of water in a water tank when the tank waggles is simulated.We demonstrate that this technology can be implemented without a significant increase in the computational cost with respect to standard numerical methods.展开更多
Rotational seismology is an emerging field for studying all aspects of rotational ground motions induced by earthquakes,explosions,and ambient vibrations. It is of interest to a wide range of geophysical disciplines,i...Rotational seismology is an emerging field for studying all aspects of rotational ground motions induced by earthquakes,explosions,and ambient vibrations. It is of interest to a wide range of geophysical disciplines,including strong-motion seismology,earthquake engineering,earthquake physics,seismic instrumentation,as well as to the complete description of particle motions( translational motion,rotational motion and deformation).This article mainly summarizes the application of rotational motions to seismology. Based on the collocated measurements of translational motion and rotational motion, the theoretical formulas of calculating the teleseismic Rayleigh wave and the Love wave phase velocity are derived. Taking the Siberian earthquake as an example,the phase velocity structure near the station is calculated. As a ring laser that's sensitive only to SH-type motion,one of the expectations of the ring laser measurements is to help seismologists separate P and S waves in the wave field. It also helps distinguish Love and Rayleigh wave energy in the ocean-generated noise field,as well as determine the back azimuth of oceanic noise sources. The long-period toroidal modes of free oscillation, one of the most challenging observations in seismology,are then observed with a ring laser. Finally,the importance and practicability of multi-parameter inversions including rotational observations are expounded. At the end of this paper,we present the existing problems in rotational seismology research and its broad application prospects.展开更多
Environment and disaster monitoring and forecasting small satellite constellation A and B satellites(HJ-1-A,B) are called "environment and disaster reduction satellites A and B" for short.The constellation a...Environment and disaster monitoring and forecasting small satellite constellation A and B satellites(HJ-1-A,B) are called "environment and disaster reduction satellites A and B" for short.The constellation adopts a 10:30LT sun-synchronous circular orbit,with orbit altitude of 649km.HJ1-A and HJ-1-B are distributed with a phase difference of 180° in the same orbital plane,so as to enhance the time resolution of earth observation.The satellites have orbit maintenance capability,the lifetime is 3 years.Both satellites adopt CAST968 platforms.Two wide-coverage multispectral CCD cameras with resolution 30m and width 700km,a super-spectral imager with resolution 100m and width 50km as well as a data transmission subsystem of 120Mbit/s are deployed on HJ-1-A,which also carries Ka communication testing equipment of Thailand.HJ-1-B has two wide-coverage multispectral CCD cameras(the same as satellite A),one infrared camera with resolution 150m and width 720km and a data transmission subsystem of 60Mbit/s.The coverage period of the wide-coverage multispectral CCD camera is 48 hours.The revisit period of super-spectral imager is 96 hours and the coverage period ofinfrared camera is 96 hours.展开更多
Single-atom catalysts were widely used to treat atmospheric pollution and alleviate energy crises through photocatalysis.However,how to prevent the aggregation of single atoms during the preparation and catalytic proc...Single-atom catalysts were widely used to treat atmospheric pollution and alleviate energy crises through photocatalysis.However,how to prevent the aggregation of single atoms during the preparation and catalytic processes remained a great challenge.Herein,a novel ultrathin two-dimensional porphyrin-based single-atom photocatalyst Ti-MOF(abbreviated as TMPd)obtained through a simple hydrothermal synthesis strategy was used for photocatalytic hydrogen evolution and NO removal,in which the singleatom Pd tightly anchored in the center of porphyrin to ensure single-atom Pd stable existence.Compared with most reported MOFs-based photocatalysts,the TMPd showed an excellent hydrogen evolution rate(1.32 mmol g^(-1)h^(-1))and the NO removal efficiency(62%)under visible light irradiation.Aberrationcorrected high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM)and synchrotron-radiation-based X-ray absorption fine-structure spectroscopy(XAFS)proved that pd in TMPd existed in an isolated state,and the atomic force microscope(AFM)proved the ultrathin morphology of TMPd.DFT calculations had demonstrated that single-atom Pd could serve as the active center and more effectively achieve electron transfer,indicating that single-atom Pd played a vital role in photocatalytic hydrogen evolution.In addition,a possible photocatalytic pathway of NO removal was proposed based on ESR and in-situ infrared spectra,in which the catalysts anchored with single-atom Pd could produce more active substances and more effectively oxidize NO to NO_(2)^(-)or NO_(3)^(-).The results suggested that coordinating single-atom metal species as the active site in the center of porphyrin could be a feasible strategy to obtain various ultrathin porphyrin-based single-atom photocatalysts to acquire excellent photocatalytic performance further.展开更多
An increasing number of low,medium,and high resolution SAR satellites creates a demand for a generalized sensor model to replace the rigorous sensor model(RSM).The rational polynomial coefficient(RPC)model is a generi...An increasing number of low,medium,and high resolution SAR satellites creates a demand for a generalized sensor model to replace the rigorous sensor model(RSM).The rational polynomial coefficient(RPC)model is a generic sensor model which accurately fits the object-image geometry for various sensor systems with different coefficient values.It has been widely used as an alternative to RSM for photogrammetric processing of optical images,but its applications to SAR images are rarely discussed in publications.In this paper,the feasibility and practicability of the RPC model for SAR images are studied.The RPC model can not only be used to replace the RSM(range–Doppler model for SAR),but also applied to the processing chain for SAR data,thus facilitating the processing of SAR and InSAR data for end users.展开更多
Herein, some fundamental open questions on engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials are considered, namely: 1) on thermodynamic stability and related characteristics of some h...Herein, some fundamental open questions on engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials are considered, namely: 1) on thermodynamic stability and related characteristics of some hydrogenated graphene layers nanostructures: relevance to the hydrogen storage problem;2) determination of thermodynamic characteristics of graphene hydrides;3) a treatment and interpretation of some recent STM, STS, HREELS/LEED, PES, ARPS and Raman spectroscopy data on hydrogensorbtion with epitaxial graphenes;4) on the physics of intercalation of hydrogen into surface graphene-like nanoblisters in pyrolytic graphite and epitaxial graphenes;5) on the physics of the elastic and plastic deformation of graphene walls in hydrogenated graphite nanofibers;6) on the physics of engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials, in the light of analysis of the Rodriguez-Baker extraordinary data and some others. These fundamental open questions may be solved within several years.展开更多
Great earthquakes often occur along or near active fault belts. Thus,monitoring and research on fault deformation are quite important. Methods such as short-leveling,shortbaseline and integrated monitoring profile acr...Great earthquakes often occur along or near active fault belts. Thus,monitoring and research on fault deformation are quite important. Methods such as short-leveling,shortbaseline and integrated monitoring profile across fault belts have been used to monitor fault activities for many years. GNSS observations are mainly used to obtain the horizontal velocity field in large areas and to study the activities and deformation of major blocks.GNSS technology has been used to monitor and study the deformation of faults from a different aspects. In this paper,some applications and new explorations of GNSS are discussed. They are:( 1) Research and monitoring of strike-slip activities of faults with GNSS.( 2) Research and monitoring of vertical activities of faults with GNSS.( 3)Investigating the laws of deformation of blocks on the sides of fault zone and setting up strain models to deduce the activities and deformation of faults with respective models and compare the deduced results with the actual measurements across fault. It is concluded that a larger discrepancy between the deduced and the observed deformation indicates a stronger interaction between the blocks,which can be important for predicting the location of a strong earthquake and assessing seismic hazard,as well as the seismicity trend.展开更多
In this paper the method of combining the Bursa model to integrate several regional time series to derive a unified global time series is introduced in detail. Then,an example taken from CMONOC( Crustal Movement Obser...In this paper the method of combining the Bursa model to integrate several regional time series to derive a unified global time series is introduced in detail. Then,an example taken from CMONOC( Crustal Movement Observation Network of China) is used to test if the combination method is feasible. The precision of the integrated time series with the combination method is below 2mm( North),3mm( East),that is same as the results from the direct integration of the time series and the precision of the baseline is below 6mm,which proves that the combination method can be used to integrate several regional time series to derive a unified global time series.展开更多
Basic surveying and mapping involves a lot of content, which is a systematic and complex work. In actual surveying and mapping, it is necessary not only to improve the accuracy of surveying and mapping, but also to fu...Basic surveying and mapping involves a lot of content, which is a systematic and complex work. In actual surveying and mapping, it is necessary not only to improve the accuracy of surveying and mapping, but also to further improve the efficiency of surveying and mapping. In recent years, UAV technology has developed rapidly, and UAV remote sensing mapping has also become a new surveying and mapping technology. It can use corresponding equipment to control UAVs and photographic equipment to obtain corresponding information. However, the UAV remote sensing mapping technology is still in the initial stage of development at this stage, and further research on practical problems needs to be enhanced when applied in basic surveying and mapping, so as to effectively promote the development of UAV remote sensing mapping technology.展开更多
The development and applications of low temperature plasma technology used in surface modification of materials are presented in this paper. Based on plasma sources and ion sources technology, multi-functions ion impl...The development and applications of low temperature plasma technology used in surface modification of materials are presented in this paper. Based on plasma sources and ion sources technology, multi-functions ion implantation and deposition technologies were developed and the related processes are also used to treat different products. The related technologies were translated into industrial productions supported by national research projects. Following the last development of international plasma researches, the standardization and internationalization processes of plasma technologies are executed in our center.展开更多
The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications.These materials are promising candidates for next-generation photodetectors(...The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications.These materials are promising candidates for next-generation photodetectors(PDs)due to their unique optoelectronic properties and flexible synthesis routes.This review explores the approaches used in the development and use of optoelectronic devices made of different nanoscale perovskite architectures,including quantum dots,nanosheets,nanorods,nanowires,and nanocrystals.Through a thorough analysis of recent literature,the review also addresses common issues like the mechanisms underlying the degradation of perovskite PDs and offers perspectives on potential solutions to improve stability and scalability that impede widespread implementation.In addition,it highlights that photodetection encompasses the detection of light fields in dimensions other than light intensity and suggests potential avenues for future research to overcome these obstacles and fully realize the potential of nanoscale perovskite materials in state-of-the-art photodetection systems.This review provides a comprehensive overview of nanoscale perovskite PDs and guides future research efforts towards improved performance and wider applicability,making it a valuable resource for researchers.展开更多
The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and...The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and diurnal temperature than between leaf onset and average temperature,current research on modeling spring phenology based on diurnal temperature indicators remains limited.In this study,we confirmed the start of the growing season(SOS)sensitivity to diurnal temperature and average temperature in boreal forest.The estimation of SOS was carried out by employing K-Nearest Neighbor Regression(KNR-TDN)model,Random Forest Regres-sion(RFR-TDN)model,eXtreme Gradient Boosting(XGB-TDN)model and Light Gradient Boosting Machine model(LightGBM-TDN)driven by diurnal temperature indicators during 1982-2015,and the SOS was projected from 2015 to 2100 based on the Coupled Model Intercomparison Project Phase 6(CMIP6)climate scenario datasets.The sensitivity of boreal forest SOS to daytime temperature is greater than that to average temperature and nighttime temperature.The LightGBM-TDN model perform best across all vegetation types,exhibiting the lowest RMSE and bias compared to the KNR-TDN model,RFR-TDN model and XGB-TDN model.By incorporating diurn-al temperature indicators instead of relying only on average temperature indicators to simulate spring phenology,an improvement in the accuracy of the model is achieved.Furthermore,the preseason accumulated daytime temperature,daytime temperature and snow cover end date emerged as significant drivers of the SOS simulation in the study area.The simulation results based on LightGBM-TDN model exhibit a trend of advancing SOS followed by stabilization under future climate scenarios.This study underscores the potential of diurn-al temperature indicators as a viable alternative to average temperature indicators in driving spring phenology models,offering a prom-ising new method for simulating spring phenology.展开更多
Quantitative studies on the interseismic and coseismic deformation characteristics and analysis of the interplay between the seismogenic fault and neighboring faults are crucial for understanding the kinematic feature...Quantitative studies on the interseismic and coseismic deformation characteristics and analysis of the interplay between the seismogenic fault and neighboring faults are crucial for understanding the kinematic features and assessing potential seismic hazards. In this study, the interseismic and coseismic deformation of the 2023 Jishishan M_(S)6.2 earthquake(JSSEQ), including the strain rate field, the slip rates,and locking depths of the seismogenic fault during the interseismic period, were obtained. Moreover, the coseismic slip distribution and geometric attributes of the seismogenic fault were further examined.Finally, the potential earthquake hazard in the vicinity was identified by analyzing the Coulomb failure stress changes(ΔCFS). Before the JSSEQ, the maximum shear and dilatational strain rates near the epicenter were significantly lower, and the seismogenic fault was strongly coupled with thrust and dextral strike-slip motion. The maximum displacement of GNSS stations is about 25 mm, about 11 km southwest of the epicenter. The ascending and descending observations reveal a significantly thrustdominated movement, with maximum line of sight displacements of 78 and 83 mm, respectively.Comparing two coseismic slip distribution results and previous studies, it is considered that the east dipping seismogenic fault is more reasonable. The coseismic fault slip took place at a depth of 7.1-13.2 km, with a maximum slip of 0.43 m and a moment magnitude of 6.1. The earthquake resulted in noticeable stress loading on the southeastern end of the Lajishan north margin fault zone and the Lajishan south margin fault zone, as well as the western end of the West Qinling fault zone, which should be given more attention in future.展开更多
On April 3,2024,an M 7.3 earthquake occurred in the offshore area of Hualien County,Taiwan,China.The seismogenic structure at the epicentral location was highly complex,and studying this earthquake is paramount for un...On April 3,2024,an M 7.3 earthquake occurred in the offshore area of Hualien County,Taiwan,China.The seismogenic structure at the epicentral location was highly complex,and studying this earthquake is paramount for understanding regional fault activity.In this study,we employed ascending and descending orbit Sentinel-1 Synthetic Aperture Radar(SAR)data and utilized differential interferometry(InSAR)technique to obtain the co-seismic deformation field of this event.The line-of-sight deformation field revealed that the main deformation caused by this earthquake was predominantly uplift,with maximum uplift values of approximately 38.8 cm and 46.1 cm for the ascending and descending orbits,respectively.By integrating the three-dimensional GNSS coseismic deformation field,we identified the seismogenic fault located in the offshore thrust zone east of Hualien,trending towards the northwest.The fault geometry parameters,obtained through the inversion of an elastic half-space homogeneous model,indicated an optimal fault strike of 196°,a dip angle of 30.9°,and an average strike-slip of 0.4 m and dip-slip of-2.6 m.This suggests that the predominant motion along the seismogenic fault is thrusting.The distribution of post-seismic Coulomb stress changes revealed that aftershocks mainly occurred in stress-loaded regions.However,stress loading was observed along the northern segment of the Longitudinal Valley Fault,with fewer aftershocks.This highlights the importance of closely monitoring the seismic hazard associated with this fault segment.展开更多
In this study,injectable bone graft putty samples were developed using fine and coarse melt-quenched 45S5 bioactive glass(BG)incorporated into a carrier system composed of glycerol and polyethylene glycol(PEG)with dif...In this study,injectable bone graft putty samples were developed using fine and coarse melt-quenched 45S5 bioactive glass(BG)incorporated into a carrier system composed of glycerol and polyethylene glycol(PEG)with different average molecular weights.Selected putty samples were further incorporated with varying amounts of Denosumab(5wt%-10wt%)to investigate its influence on rhe-ological behavior and flow properties using mathematical modeling.All PEG/glycerol/45S5-based putty samples exhibited viscoelastic behavior(storage modulus>loss modulus)and pseudoplastic behavior(n<1),with viscosity values required for optimal flow remaining below 1000 Pa∙s.Both viscosity and thixotropic area increased proportionally with higher BG content and smaller-sized BG particles.All putty samples showed more than 98%injectability through a 12G cannula,suggesting potential clinical suitability.However,injectability decreased with smaller cannulas,dropping to 34.7%-58.3%with a 19G cannula and further decreasing with a 23G cannula at higher BG contents.Incorporation of Denosumab preserved viscoelasticity and injectability but modified the flow behavior,shifting it from pseudo-plastic to more Newtonian with higher Denosumab content,while also reducing viscosity and thixotropic area values.Among all tested samples,putty containing a lower amount of Denosumab and smaller-sized BG exhibited the most suitable combination of injectability and rheological features.All putty samples were well described by both the Power law and Herschel-Bulkley rheological models(coeffi-cient of determination>0.95).This study highlights the influence of Denosumab on flowability and rheological relationships and sug-gests potential improvements in bioactivity through a dual synergistic effect of BG and Denosumab in minimally invasive bone graft sys-tems.展开更多
Adenomatous polyposis coli(APC)mutations are the most frequently identified genetic alteration in sporadic colorectal cancer(CRC)cases,and a myriad of genetically engineered Apc-mutant CRC mouse models have been devel...Adenomatous polyposis coli(APC)mutations are the most frequently identified genetic alteration in sporadic colorectal cancer(CRC)cases,and a myriad of genetically engineered Apc-mutant CRC mouse models have been developed using various genetic manipulation techniques.The advent of the CRISPR/Cas9 system has revolutionized the field of genetic engineering and facilitated the development of new genetically engineered mouse models.In this study,we aimed to develop a novel Apc knockout allele using the CRISPR/Cas9 system and evaluate the phenotypic effects of this new allele in two different mouse strains.For this purpose,exon 16 of mouse Apc gene was targeted with a single-guide RNA,and the mouse carrying an Apc frameshift mutation at codon 750(^(Δ750))was chosen as the founder.The mutant FVB-Apc^(Δ750)mice were backcrossed with wild-type C57BL/6 mice,and the phenotypic effects of the knockout allele were evaluated in F8-FVB-Apc^(Δ750),F4-B6;FVB-Apc^(Δ750),and F1-B6;FVB-Apc^(Δ750)by a macroscopic and microscopic examination of the gastrointestinal system.The result showed that the mean polyp number was significantly higher in F4-BL6;FVB-Apc^(Δ750)than in F8-FVB-Apc^(Δ750).Intestinal polyposis was more prominent in F4-BL6;FVB-Apc^(Δ750),whereas a higher number of colon polyps than intestinal polyps were observed in F8-FVB-Apc^(Δ750).Additionally,F1-BL6;FVB-Apc^(Δ750)mixed background mice developed gastric polyps that morphologically resembled the pyloric gland adenoma of humans.In conclusion,we developed a novel CRISPR-mediated Apc knockout allele using two mouse strains.We showed that this allele can exert a strainspecific effect on the phenotype of mice and can cause gastric polyp formation.展开更多
Due to the continuously increasing building and construction industry,sand has become one of the most questioned raw materials worldwide.However,the available amount of sand suitable for concrete production is orders ...Due to the continuously increasing building and construction industry,sand has become one of the most questioned raw materials worldwide.However,the available amount of sand suitable for concrete production is orders of magnitude lower that the demand and consumption.Even though desert sand is sufficiently available,it is not usable for realizing stable concrete due to its surface shape.Against this background,the suitability of energy-efficient‘cold'dielectric barrier discharge plasma operated at atmospheric pressure for improving the properties of concrete produced from desert sand was investigated in this contribution.It is shown that such plasma treatment allows for a certain roughening and re-shaping of sand grains.As a result,the mass flow of treated sand is decreased due to an improved wedging of sand grains.This leads to a certain increase in compressive strength of concrete samples.Even though this increase is marginal,the suitability of the applied type of plasma for modification of the geometry and surface chemistry of sand grains was proven,showing its basic potential for the treatment and preconditioning of sand used for concrete,mortar or plastering.展开更多
Many experiments have supported the contact models,such as the GW and MB models,but the majority of previous validations have been performed under light loads,resulting in a linear relationship between normal force an...Many experiments have supported the contact models,such as the GW and MB models,but the majority of previous validations have been performed under light loads,resulting in a linear relationship between normal force and contact area.However,the real contact area fraction should never equal one;there must be a limit smaller than the apparent area,implying that the real contact area cannot increase linearly indefinitely.In this paper,the real contact area between two polymethylmethacrylate(PMMA)blocks under heavy load is measured using the total reflection method,and the contact area is analyzed using the image processing method.The results show that the real contact area increases with normal load linearly in light loads but non-linearly in heavy loads;the number of contact spots increases with load linearly in light loads but also non-linearly in heavy loads,synchronous with the change in the real contact area.The GW,MB,and Zhao,Maietta,and Chang(ZMC)models were used to predict the experiment results,but none of them predicted the non-linear stage.A revised GW model based on the bulk deformation hypothesis performs better in predicting the non-linear stage.The study’s findings can be applied to PMMA or other similar materials,and they can serve as a useful reference for future research on the contact mechanisms of other materials.展开更多
Accurate traffic flow prediction(TFP)is vital for efficient and sustainable transportation management and the development of intelligent traffic systems.However,missing data in real-world traffic datasets poses a sign...Accurate traffic flow prediction(TFP)is vital for efficient and sustainable transportation management and the development of intelligent traffic systems.However,missing data in real-world traffic datasets poses a significant challenge to maintaining prediction precision.This study introduces REPTF-TMDI,a novel method that combines a Reduced Error Pruning Tree Forest(REPTree Forest)with a newly proposed Time-based Missing Data Imputation(TMDI)approach.The REP Tree Forest,an ensemble learning approach,is tailored for time-related traffic data to enhance predictive accuracy and support the evolution of sustainable urbanmobility solutions.Meanwhile,the TMDI approach exploits temporal patterns to estimate missing values reliably whenever empty fields are encountered.The proposed method was evaluated using hourly traffic flow data from a major U.S.roadway spanning 2012-2018,incorporating temporal features(e.g.,hour,day,month,year,weekday),holiday indicator,and weather conditions(temperature,rain,snow,and cloud coverage).Experimental results demonstrated that the REPTF-TMDI method outperformed conventional imputation techniques across various missing data ratios by achieving an average 11.76%improvement in terms of correlation coefficient(R).Furthermore,REPTree Forest achieved improvements of 68.62%in RMSE and 70.52%in MAE compared to existing state-of-the-art models.These findings highlight the method’s ability to significantly boost traffic flow prediction accuracy,even in the presence of missing data,thereby contributing to the broader objectives of sustainable urban transportation systems.展开更多
基金supported by the Science for Earthquake Resilience(XH14070Y,XH15064Y)the China NationalSpecial Fund for Earthquake Scientific Research in Public Interest(201208009)
文摘The correction for antenna phase center is considered in processing Global Positioning System （GPS） data collected from a network of GPS ultra-short baselines. Compared with the leveling measurements, the GPS results show that the relative vertical offsets for the pairs of GPS receiver antenna phase centers still exist, although absolute calibration of the antenna phase center variations （PCVs） has been considered. With respect to the TPS CR.G3 antenna, the relative vertical offset for the LEI AT504 antenna is 8.4 mm, the offset for the ASH701945C_M antenna is 5.5 mm, and those for the ASHY00936E_C and ASH701945B_M antennas are approximately between 2 mm and -3 mm. The relative offsets for the same type of antennas are approximately 1 mm. By correcting the absolute PCVs, the existing relative offset becomes negligible for horizontal positioning.
基金by the National Natural Science Foundation of China(51808201).
文摘On the basis of harmonic mapping theory,a mobile grid technology is applied to computational fluid dynamics(CFD).Starting from the observation that standard fixed-grid techniques often fail in addressing problems with large deformations,we elaborate a new algorithm relying on the software COMSOL Multiphysics 5.3a to solve the coupling of the mobile grid equation and the governing differential equations for fluid flow.The motion of water in a water tank when the tank waggles is simulated.We demonstrate that this technology can be implemented without a significant increase in the computational cost with respect to standard numerical methods.
基金sponsored by the China National Special Fund of Earthquake Scientific Research in Public Interest(201508009)
文摘Rotational seismology is an emerging field for studying all aspects of rotational ground motions induced by earthquakes,explosions,and ambient vibrations. It is of interest to a wide range of geophysical disciplines,including strong-motion seismology,earthquake engineering,earthquake physics,seismic instrumentation,as well as to the complete description of particle motions( translational motion,rotational motion and deformation).This article mainly summarizes the application of rotational motions to seismology. Based on the collocated measurements of translational motion and rotational motion, the theoretical formulas of calculating the teleseismic Rayleigh wave and the Love wave phase velocity are derived. Taking the Siberian earthquake as an example,the phase velocity structure near the station is calculated. As a ring laser that's sensitive only to SH-type motion,one of the expectations of the ring laser measurements is to help seismologists separate P and S waves in the wave field. It also helps distinguish Love and Rayleigh wave energy in the ocean-generated noise field,as well as determine the back azimuth of oceanic noise sources. The long-period toroidal modes of free oscillation, one of the most challenging observations in seismology,are then observed with a ring laser. Finally,the importance and practicability of multi-parameter inversions including rotational observations are expounded. At the end of this paper,we present the existing problems in rotational seismology research and its broad application prospects.
文摘Environment and disaster monitoring and forecasting small satellite constellation A and B satellites(HJ-1-A,B) are called "environment and disaster reduction satellites A and B" for short.The constellation adopts a 10:30LT sun-synchronous circular orbit,with orbit altitude of 649km.HJ1-A and HJ-1-B are distributed with a phase difference of 180° in the same orbital plane,so as to enhance the time resolution of earth observation.The satellites have orbit maintenance capability,the lifetime is 3 years.Both satellites adopt CAST968 platforms.Two wide-coverage multispectral CCD cameras with resolution 30m and width 700km,a super-spectral imager with resolution 100m and width 50km as well as a data transmission subsystem of 120Mbit/s are deployed on HJ-1-A,which also carries Ka communication testing equipment of Thailand.HJ-1-B has two wide-coverage multispectral CCD cameras(the same as satellite A),one infrared camera with resolution 150m and width 720km and a data transmission subsystem of 60Mbit/s.The coverage period of the wide-coverage multispectral CCD camera is 48 hours.The revisit period of super-spectral imager is 96 hours and the coverage period ofinfrared camera is 96 hours.
基金supported by the National Natural Science Foundation of China(Nos.22001026,21502012)the Chongqing Science and Technology Commission(Nos.CSTB2022NSCQ-MSX1308,CSTB2023NSCQ-MSX0670)+4 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJZDK202300806)Graduate Innovation Program of Chongqing Technology and Business University(No.yjscxx2023–211–41)Student Development Assistance Program of Chongqing Technology and Business University(No.2021412237)Fund of National-local Joint Engineering Research Center for Road Engineering and Disaster Prevention and Reduction Technology in Mountainous Areas(No.SQDL-2021–01)Cultural Relics Protection Research Project of Chongqing Bureau of Cultural Relics(2022No.318)。
文摘Single-atom catalysts were widely used to treat atmospheric pollution and alleviate energy crises through photocatalysis.However,how to prevent the aggregation of single atoms during the preparation and catalytic processes remained a great challenge.Herein,a novel ultrathin two-dimensional porphyrin-based single-atom photocatalyst Ti-MOF(abbreviated as TMPd)obtained through a simple hydrothermal synthesis strategy was used for photocatalytic hydrogen evolution and NO removal,in which the singleatom Pd tightly anchored in the center of porphyrin to ensure single-atom Pd stable existence.Compared with most reported MOFs-based photocatalysts,the TMPd showed an excellent hydrogen evolution rate(1.32 mmol g^(-1)h^(-1))and the NO removal efficiency(62%)under visible light irradiation.Aberrationcorrected high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM)and synchrotron-radiation-based X-ray absorption fine-structure spectroscopy(XAFS)proved that pd in TMPd existed in an isolated state,and the atomic force microscope(AFM)proved the ultrathin morphology of TMPd.DFT calculations had demonstrated that single-atom Pd could serve as the active center and more effectively achieve electron transfer,indicating that single-atom Pd played a vital role in photocatalytic hydrogen evolution.In addition,a possible photocatalytic pathway of NO removal was proposed based on ESR and in-situ infrared spectra,in which the catalysts anchored with single-atom Pd could produce more active substances and more effectively oxidize NO to NO_(2)^(-)or NO_(3)^(-).The results suggested that coordinating single-atom metal species as the active site in the center of porphyrin could be a feasible strategy to obtain various ultrathin porphyrin-based single-atom photocatalysts to acquire excellent photocatalytic performance further.
基金Supported by National Technology Support Project(Nos.2011BAB01B01,2012BAH28B04)the National Natural Science Foundation of China(No.40930532)the National High Technology Research&Development Programme of China(No.2011AA120404).
文摘An increasing number of low,medium,and high resolution SAR satellites creates a demand for a generalized sensor model to replace the rigorous sensor model(RSM).The rational polynomial coefficient(RPC)model is a generic sensor model which accurately fits the object-image geometry for various sensor systems with different coefficient values.It has been widely used as an alternative to RSM for photogrammetric processing of optical images,but its applications to SAR images are rarely discussed in publications.In this paper,the feasibility and practicability of the RPC model for SAR images are studied.The RPC model can not only be used to replace the RSM(range–Doppler model for SAR),but also applied to the processing chain for SAR data,thus facilitating the processing of SAR and InSAR data for end users.
文摘Herein, some fundamental open questions on engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials are considered, namely: 1) on thermodynamic stability and related characteristics of some hydrogenated graphene layers nanostructures: relevance to the hydrogen storage problem;2) determination of thermodynamic characteristics of graphene hydrides;3) a treatment and interpretation of some recent STM, STS, HREELS/LEED, PES, ARPS and Raman spectroscopy data on hydrogensorbtion with epitaxial graphenes;4) on the physics of intercalation of hydrogen into surface graphene-like nanoblisters in pyrolytic graphite and epitaxial graphenes;5) on the physics of the elastic and plastic deformation of graphene walls in hydrogenated graphite nanofibers;6) on the physics of engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials, in the light of analysis of the Rodriguez-Baker extraordinary data and some others. These fundamental open questions may be solved within several years.
基金sponsored by the Special Fund of CEA(201308009)the Spark Program of CEA(XH12071)
文摘Great earthquakes often occur along or near active fault belts. Thus,monitoring and research on fault deformation are quite important. Methods such as short-leveling,shortbaseline and integrated monitoring profile across fault belts have been used to monitor fault activities for many years. GNSS observations are mainly used to obtain the horizontal velocity field in large areas and to study the activities and deformation of major blocks.GNSS technology has been used to monitor and study the deformation of faults from a different aspects. In this paper,some applications and new explorations of GNSS are discussed. They are:( 1) Research and monitoring of strike-slip activities of faults with GNSS.( 2) Research and monitoring of vertical activities of faults with GNSS.( 3)Investigating the laws of deformation of blocks on the sides of fault zone and setting up strain models to deduce the activities and deformation of faults with respective models and compare the deduced results with the actual measurements across fault. It is concluded that a larger discrepancy between the deduced and the observed deformation indicates a stronger interaction between the blocks,which can be important for predicting the location of a strong earthquake and assessing seismic hazard,as well as the seismicity trend.
基金sponsored by the Earthquake Tracing Task Contract of the Year 2012,China Earthquake Administration(2012020205)
文摘In this paper the method of combining the Bursa model to integrate several regional time series to derive a unified global time series is introduced in detail. Then,an example taken from CMONOC( Crustal Movement Observation Network of China) is used to test if the combination method is feasible. The precision of the integrated time series with the combination method is below 2mm( North),3mm( East),that is same as the results from the direct integration of the time series and the precision of the baseline is below 6mm,which proves that the combination method can be used to integrate several regional time series to derive a unified global time series.
文摘Basic surveying and mapping involves a lot of content, which is a systematic and complex work. In actual surveying and mapping, it is necessary not only to improve the accuracy of surveying and mapping, but also to further improve the efficiency of surveying and mapping. In recent years, UAV technology has developed rapidly, and UAV remote sensing mapping has also become a new surveying and mapping technology. It can use corresponding equipment to control UAVs and photographic equipment to obtain corresponding information. However, the UAV remote sensing mapping technology is still in the initial stage of development at this stage, and further research on practical problems needs to be enhanced when applied in basic surveying and mapping, so as to effectively promote the development of UAV remote sensing mapping technology.
文摘The development and applications of low temperature plasma technology used in surface modification of materials are presented in this paper. Based on plasma sources and ion sources technology, multi-functions ion implantation and deposition technologies were developed and the related processes are also used to treat different products. The related technologies were translated into industrial productions supported by national research projects. Following the last development of international plasma researches, the standardization and internationalization processes of plasma technologies are executed in our center.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.RS-2022–00165798)Anhui Natural Science Foundation(No.2308085MF211)The authors extend their appreciation to the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under Grant Number(R.G.P.2/491/45).
文摘The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications.These materials are promising candidates for next-generation photodetectors(PDs)due to their unique optoelectronic properties and flexible synthesis routes.This review explores the approaches used in the development and use of optoelectronic devices made of different nanoscale perovskite architectures,including quantum dots,nanosheets,nanorods,nanowires,and nanocrystals.Through a thorough analysis of recent literature,the review also addresses common issues like the mechanisms underlying the degradation of perovskite PDs and offers perspectives on potential solutions to improve stability and scalability that impede widespread implementation.In addition,it highlights that photodetection encompasses the detection of light fields in dimensions other than light intensity and suggests potential avenues for future research to overcome these obstacles and fully realize the potential of nanoscale perovskite materials in state-of-the-art photodetection systems.This review provides a comprehensive overview of nanoscale perovskite PDs and guides future research efforts towards improved performance and wider applicability,making it a valuable resource for researchers.
基金Under the auspices of National Natural Science Foundation of China(No.42201374,42071359)。
文摘The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and diurnal temperature than between leaf onset and average temperature,current research on modeling spring phenology based on diurnal temperature indicators remains limited.In this study,we confirmed the start of the growing season(SOS)sensitivity to diurnal temperature and average temperature in boreal forest.The estimation of SOS was carried out by employing K-Nearest Neighbor Regression(KNR-TDN)model,Random Forest Regres-sion(RFR-TDN)model,eXtreme Gradient Boosting(XGB-TDN)model and Light Gradient Boosting Machine model(LightGBM-TDN)driven by diurnal temperature indicators during 1982-2015,and the SOS was projected from 2015 to 2100 based on the Coupled Model Intercomparison Project Phase 6(CMIP6)climate scenario datasets.The sensitivity of boreal forest SOS to daytime temperature is greater than that to average temperature and nighttime temperature.The LightGBM-TDN model perform best across all vegetation types,exhibiting the lowest RMSE and bias compared to the KNR-TDN model,RFR-TDN model and XGB-TDN model.By incorporating diurn-al temperature indicators instead of relying only on average temperature indicators to simulate spring phenology,an improvement in the accuracy of the model is achieved.Furthermore,the preseason accumulated daytime temperature,daytime temperature and snow cover end date emerged as significant drivers of the SOS simulation in the study area.The simulation results based on LightGBM-TDN model exhibit a trend of advancing SOS followed by stabilization under future climate scenarios.This study underscores the potential of diurn-al temperature indicators as a viable alternative to average temperature indicators in driving spring phenology models,offering a prom-ising new method for simulating spring phenology.
基金funded by the National Natural Science Foundation of China (Grant No. 42204008)the National Key Research and Development Program of China (No. 2022YFC3003703)the Scientific Research Project Coordinating Fund of the First Monitoring and Application Center, China Earthquake Administration (No. FMC2022014)
文摘Quantitative studies on the interseismic and coseismic deformation characteristics and analysis of the interplay between the seismogenic fault and neighboring faults are crucial for understanding the kinematic features and assessing potential seismic hazards. In this study, the interseismic and coseismic deformation of the 2023 Jishishan M_(S)6.2 earthquake(JSSEQ), including the strain rate field, the slip rates,and locking depths of the seismogenic fault during the interseismic period, were obtained. Moreover, the coseismic slip distribution and geometric attributes of the seismogenic fault were further examined.Finally, the potential earthquake hazard in the vicinity was identified by analyzing the Coulomb failure stress changes(ΔCFS). Before the JSSEQ, the maximum shear and dilatational strain rates near the epicenter were significantly lower, and the seismogenic fault was strongly coupled with thrust and dextral strike-slip motion. The maximum displacement of GNSS stations is about 25 mm, about 11 km southwest of the epicenter. The ascending and descending observations reveal a significantly thrustdominated movement, with maximum line of sight displacements of 78 and 83 mm, respectively.Comparing two coseismic slip distribution results and previous studies, it is considered that the east dipping seismogenic fault is more reasonable. The coseismic fault slip took place at a depth of 7.1-13.2 km, with a maximum slip of 0.43 m and a moment magnitude of 6.1. The earthquake resulted in noticeable stress loading on the southeastern end of the Lajishan north margin fault zone and the Lajishan south margin fault zone, as well as the western end of the West Qinling fault zone, which should be given more attention in future.
基金supported by Shaanxi Province Natural Science Foundation Research Program[Grant number 2023JC-QN-0296]。
文摘On April 3,2024,an M 7.3 earthquake occurred in the offshore area of Hualien County,Taiwan,China.The seismogenic structure at the epicentral location was highly complex,and studying this earthquake is paramount for understanding regional fault activity.In this study,we employed ascending and descending orbit Sentinel-1 Synthetic Aperture Radar(SAR)data and utilized differential interferometry(InSAR)technique to obtain the co-seismic deformation field of this event.The line-of-sight deformation field revealed that the main deformation caused by this earthquake was predominantly uplift,with maximum uplift values of approximately 38.8 cm and 46.1 cm for the ascending and descending orbits,respectively.By integrating the three-dimensional GNSS coseismic deformation field,we identified the seismogenic fault located in the offshore thrust zone east of Hualien,trending towards the northwest.The fault geometry parameters,obtained through the inversion of an elastic half-space homogeneous model,indicated an optimal fault strike of 196°,a dip angle of 30.9°,and an average strike-slip of 0.4 m and dip-slip of-2.6 m.This suggests that the predominant motion along the seismogenic fault is thrusting.The distribution of post-seismic Coulomb stress changes revealed that aftershocks mainly occurred in stress-loaded regions.However,stress loading was observed along the northern segment of the Longitudinal Valley Fault,with fewer aftershocks.This highlights the importance of closely monitoring the seismic hazard associated with this fault segment.
基金supported by Yildiz Technical University Scientific Research Projects Coordination Unit under project number FBA-2023-5377support from the Scientific and Technological Research Council of Turkey(TUBITAK)under the BIDEB/2211-A National PhD Scholarship Program and 2250-Performance-Based Scholarships Program for PhD.
文摘In this study,injectable bone graft putty samples were developed using fine and coarse melt-quenched 45S5 bioactive glass(BG)incorporated into a carrier system composed of glycerol and polyethylene glycol(PEG)with different average molecular weights.Selected putty samples were further incorporated with varying amounts of Denosumab(5wt%-10wt%)to investigate its influence on rhe-ological behavior and flow properties using mathematical modeling.All PEG/glycerol/45S5-based putty samples exhibited viscoelastic behavior(storage modulus>loss modulus)and pseudoplastic behavior(n<1),with viscosity values required for optimal flow remaining below 1000 Pa∙s.Both viscosity and thixotropic area increased proportionally with higher BG content and smaller-sized BG particles.All putty samples showed more than 98%injectability through a 12G cannula,suggesting potential clinical suitability.However,injectability decreased with smaller cannulas,dropping to 34.7%-58.3%with a 19G cannula and further decreasing with a 23G cannula at higher BG contents.Incorporation of Denosumab preserved viscoelasticity and injectability but modified the flow behavior,shifting it from pseudo-plastic to more Newtonian with higher Denosumab content,while also reducing viscosity and thixotropic area values.Among all tested samples,putty containing a lower amount of Denosumab and smaller-sized BG exhibited the most suitable combination of injectability and rheological features.All putty samples were well described by both the Power law and Herschel-Bulkley rheological models(coeffi-cient of determination>0.95).This study highlights the influence of Denosumab on flowability and rheological relationships and sug-gests potential improvements in bioactivity through a dual synergistic effect of BG and Denosumab in minimally invasive bone graft sys-tems.
基金The Scientific and Technological Research Council of Turkey 1001 program,Grant/Award Number:SBAG-215S926。
文摘Adenomatous polyposis coli(APC)mutations are the most frequently identified genetic alteration in sporadic colorectal cancer(CRC)cases,and a myriad of genetically engineered Apc-mutant CRC mouse models have been developed using various genetic manipulation techniques.The advent of the CRISPR/Cas9 system has revolutionized the field of genetic engineering and facilitated the development of new genetically engineered mouse models.In this study,we aimed to develop a novel Apc knockout allele using the CRISPR/Cas9 system and evaluate the phenotypic effects of this new allele in two different mouse strains.For this purpose,exon 16 of mouse Apc gene was targeted with a single-guide RNA,and the mouse carrying an Apc frameshift mutation at codon 750(^(Δ750))was chosen as the founder.The mutant FVB-Apc^(Δ750)mice were backcrossed with wild-type C57BL/6 mice,and the phenotypic effects of the knockout allele were evaluated in F8-FVB-Apc^(Δ750),F4-B6;FVB-Apc^(Δ750),and F1-B6;FVB-Apc^(Δ750)by a macroscopic and microscopic examination of the gastrointestinal system.The result showed that the mean polyp number was significantly higher in F4-BL6;FVB-Apc^(Δ750)than in F8-FVB-Apc^(Δ750).Intestinal polyposis was more prominent in F4-BL6;FVB-Apc^(Δ750),whereas a higher number of colon polyps than intestinal polyps were observed in F8-FVB-Apc^(Δ750).Additionally,F1-BL6;FVB-Apc^(Δ750)mixed background mice developed gastric polyps that morphologically resembled the pyloric gland adenoma of humans.In conclusion,we developed a novel CRISPR-mediated Apc knockout allele using two mouse strains.We showed that this allele can exert a strainspecific effect on the phenotype of mice and can cause gastric polyp formation.
基金funded by the Bundesministerium für Bildung und Forschung(Nos.13FH6I06IA and 13FH6I08IA)。
文摘Due to the continuously increasing building and construction industry,sand has become one of the most questioned raw materials worldwide.However,the available amount of sand suitable for concrete production is orders of magnitude lower that the demand and consumption.Even though desert sand is sufficiently available,it is not usable for realizing stable concrete due to its surface shape.Against this background,the suitability of energy-efficient‘cold'dielectric barrier discharge plasma operated at atmospheric pressure for improving the properties of concrete produced from desert sand was investigated in this contribution.It is shown that such plasma treatment allows for a certain roughening and re-shaping of sand grains.As a result,the mass flow of treated sand is decreased due to an improved wedging of sand grains.This leads to a certain increase in compressive strength of concrete samples.Even though this increase is marginal,the suitability of the applied type of plasma for modification of the geometry and surface chemistry of sand grains was proven,showing its basic potential for the treatment and preconditioning of sand used for concrete,mortar or plastering.
基金Supported by National Natural Science Foundation of China(Grant No.11872033)Beijing Municipal Natural Science Foundation(Grant No.3172017)。
文摘Many experiments have supported the contact models,such as the GW and MB models,but the majority of previous validations have been performed under light loads,resulting in a linear relationship between normal force and contact area.However,the real contact area fraction should never equal one;there must be a limit smaller than the apparent area,implying that the real contact area cannot increase linearly indefinitely.In this paper,the real contact area between two polymethylmethacrylate(PMMA)blocks under heavy load is measured using the total reflection method,and the contact area is analyzed using the image processing method.The results show that the real contact area increases with normal load linearly in light loads but non-linearly in heavy loads;the number of contact spots increases with load linearly in light loads but also non-linearly in heavy loads,synchronous with the change in the real contact area.The GW,MB,and Zhao,Maietta,and Chang(ZMC)models were used to predict the experiment results,but none of them predicted the non-linear stage.A revised GW model based on the bulk deformation hypothesis performs better in predicting the non-linear stage.The study’s findings can be applied to PMMA or other similar materials,and they can serve as a useful reference for future research on the contact mechanisms of other materials.
文摘Accurate traffic flow prediction(TFP)is vital for efficient and sustainable transportation management and the development of intelligent traffic systems.However,missing data in real-world traffic datasets poses a significant challenge to maintaining prediction precision.This study introduces REPTF-TMDI,a novel method that combines a Reduced Error Pruning Tree Forest(REPTree Forest)with a newly proposed Time-based Missing Data Imputation(TMDI)approach.The REP Tree Forest,an ensemble learning approach,is tailored for time-related traffic data to enhance predictive accuracy and support the evolution of sustainable urbanmobility solutions.Meanwhile,the TMDI approach exploits temporal patterns to estimate missing values reliably whenever empty fields are encountered.The proposed method was evaluated using hourly traffic flow data from a major U.S.roadway spanning 2012-2018,incorporating temporal features(e.g.,hour,day,month,year,weekday),holiday indicator,and weather conditions(temperature,rain,snow,and cloud coverage).Experimental results demonstrated that the REPTF-TMDI method outperformed conventional imputation techniques across various missing data ratios by achieving an average 11.76%improvement in terms of correlation coefficient(R).Furthermore,REPTree Forest achieved improvements of 68.62%in RMSE and 70.52%in MAE compared to existing state-of-the-art models.These findings highlight the method’s ability to significantly boost traffic flow prediction accuracy,even in the presence of missing data,thereby contributing to the broader objectives of sustainable urban transportation systems.
