Pedo-spectroscopy has the potential to provide valuable information about soil physical,chemical,and biological properties.Nowadays,wemay predict soil properties usingVNIRfield imaging spectra(IS)such as Prisma satell...Pedo-spectroscopy has the potential to provide valuable information about soil physical,chemical,and biological properties.Nowadays,wemay predict soil properties usingVNIRfield imaging spectra(IS)such as Prisma satellite data or laboratory spectra(LS).The primary goal of this study is to investigate machine learning models namely Partial Least Squares Regression(PLSR)and Support Vector Regression(SVR)for the prediction of several soil properties,including clay,sand,silt,organic matter,nitrate NO3-,and calcium carbonate CaCO_(3),using five VNIR spectra dataset combinations(%IS,%LS)as follows:C1(0%IS,100%LS),C2(20%IS,80%LS),C3(50%IS,50%LS),C4(80%IS,20%LS)and C5(100%IS,0%LS).Soil samples were collected at bare soils and at the upper(0–30 cm)layer.The data set has been split into a training dataset 80%of the collected data(n=248)and a validation dataset 20%of the collected data(n=61).The proposed PLSR and SVR models were trained then tested for each dataset combination.According to our results,SVR outperforms PLSR for both:C1(0%IS,100%LS)and C5(100%IS,0%LS).For Soil Organic Matter(SOM)prediction,it achieves(R^(2)=0.79%,RMSE=1.42%)and(R^(2)=0.76%,RMSE=1.3%),respectively.The data fusion has improved the soil property prediction.The highest improvement was obtained for the SOM property(R^(2)=0.80%,RMSE=1.39)when using the SVR model and applying the second Combination C2(20% of IS and 80%LS).展开更多
The surface particle size and distribution characteristics of celestial bodies (e.g.,the Moon,asteroids,etc.) will affect the interpretation of hyperspectral remote sensing data and the implementation of sampling miss...The surface particle size and distribution characteristics of celestial bodies (e.g.,the Moon,asteroids,etc.) will affect the interpretation of hyperspectral remote sensing data and the implementation of sampling missions.Currently,the estimation of the surface particle sizes is mainly focusing on interpreting the thermal inertia with the infrared spectral data from ground-based or space telescopes,but this method show distinct errors compared with the imaging results of the orbiter.By analyzing some thermal infrared spectral data,a relationship between the particle sizes of the main rockforming minerals (e.g.pyroxene,feldspar,olivine) and the slopes of their thermal infrared spectrum was found.Based on this relationship,a preliminary model for estimating the grain sizes (~30–300μm) of lunar or S-type asteroids’surfaces which are silicate minerals dominated was established,and the correlation coefficients (R^(2)) for most of the rock-forming minerals were better than 90%.Six observational datasets of natural lunar and terrestrial samples are used to validate the model,and the results show a systematical overestimation of the ground-truth particle sizes,the potential causes are analyzed and an additional correction is used to eliminate the overestimation of the particle size prediction.These results are expected to provide guidance for interpretation of lunar and S-type asteroid surface sampling and spectral data.展开更多
A series of heteronuclear yttrium-nickel monoxide carbonyl complexes YNiO(CO)_(n)^(-)(n=1-5)were generated in a pulsed-laser vaporization source and characterized by mass-selected photoelectron velocity-map spectrosco...A series of heteronuclear yttrium-nickel monoxide carbonyl complexes YNiO(CO)_(n)^(-)(n=1-5)were generated in a pulsed-laser vaporization source and characterized by mass-selected photoelectron velocity-map spectroscopy combined with theoretical calculations.CO ligand-mediated reactivity in CO oxidation of yttrium-nickel monoxide carbonyl complexes was experimentally and theoretically identified.During the consecutive CO adsorption,aμ^(2)-O linear structure was most favorable for YNiO(CO)_(n)^(-)(n=1,2),then a structure in which the terminal O was bonded to the Y atom became favored for YNiO(CO)_(3)^(-),and finally a structure bearing a CO_(2)moiety was most favorable for YNiO(CO)_(n)^(-)(n=4,5).Theoretical calculations indicated that the Ni atom acted as an electron acceptor and accumulated electron density at n≤3,and then served as an electron donor along with the Y atom to contribute electron density in the rearrangement that accompanied CO oxidation at n>3.展开更多
The static large field of the view polarization interference imaging spectrometer is based on the modified Savart polariseope. There appears a dispersion between the ordinary ray and extraordinary ray when light passe...The static large field of the view polarization interference imaging spectrometer is based on the modified Savart polariseope. There appears a dispersion between the ordinary ray and extraordinary ray when light passes through the modified Savart polariscope. The dispersion greatly influences the intensities and the results of the interferogram and target image in the static large field of the view polarization interference imaging spectrometer. At the same time, the incident angle determines the dispersion. When the light goes through the modified Savart polariscope, the dispersion occurs in the left plate, the half-wave plate and the right plate of the modified Savart polariscope. Using the extension of Shell＇s law, the dispersion in the crystal is theoretically calculated and numerically simulated separately. The relationship curve between incident angle and the dispersion is obtained by simulation.展开更多
Propagating disturbances（PDs） were studied along an active region loop using simultaneous imaging and spectroscopy. An image sequence recorded in the Fe Ⅸ/Fe X 171 channel, from TRACE and spectral data in the Si ...Propagating disturbances（PDs） were studied along an active region loop using simultaneous imaging and spectroscopy. An image sequence recorded in the Fe Ⅸ/Fe X 171 channel, from TRACE and spectral data in the Si Ⅻ 520.6 line obtained from CDS/SOHO, are analyzed. A space-time map constructed from the TRACE image sequence shows the presence of PDs close to the loop foot point propagating with an apparent speed of 39 km s-1. The periodicity was found to be 5.4 min.The corresponding spectroscopic data from CDS, at a location away from the foot point, show oscillations in all three line parameters roughly at the same period. At locations farther from the foot point, the line width oscillation seems to disappear while the Doppler velocity oscillation becomes prominent. We attribute this to the signature of propagating slow waves that get affected by flows/other events close to the foot point. Spectral line profiles do not show much asymmetry, however, it is difficult to infer anything due to the broadened Gaussian shape of the CDS line profiles.展开更多
The Mare Moscoviense is an astonishing rare flatland multi-ring basin and one of the recognizable mare regions on the Moon's farside.The mineralogical,chronological,topographical and morphological studies of the m...The Mare Moscoviense is an astonishing rare flatland multi-ring basin and one of the recognizable mare regions on the Moon's farside.The mineralogical,chronological,topographical and morphological studies of the maria surface of the Moon provide a primary understanding of the origin and evolution of the mare provinces.In this study,the Chandrayaan-1 M^(3)data have been employed to prepare optical maturity index,FeO and TiO^(2)concentration,and standard band ratio map to detect the mafic indexes like olivine and pyroxene minerals.The crater size frequency distribution method has been applied to LROC WAC data to obtain the absolute model ages of the Moscoviense basin.The four geological unit ages were observed as 3.57 Ga(U-2),3.65 Ga(U-1),3.8 Ga(U-3)and 3.92 Ga(U-4),which could have been formed between the Imbrian and Nectarian epochs.The M^(3)imaging and reflectance spectral parameters were used to reveal the minerals like pyroxene,olivine,ilmenite,plagioclase,orthopyroxene-olivine-spinel lithology,and olivine-pyroxene mixtures present in the gabbroic basalt,anorthositic and massive ilmenite rocks,and validated with the existing database.The results show that the Moscoviense basin is dominated by intermediate TiO^(2)basalts that derived from olivine-ilmenite-pyroxene cumulate depths ranging from 200 to 500 km between 3.5 Ga and 3.6 Ga.展开更多
In this paper we illustrate the technique used by the New Vacuum Solar Telescope（NVST）to increase the spatial resolution of two-dimensional（2D）solar spectroscopy observations involving two dimensions of space and ...In this paper we illustrate the technique used by the New Vacuum Solar Telescope（NVST）to increase the spatial resolution of two-dimensional（2D）solar spectroscopy observations involving two dimensions of space and one of wavelength.Without an image stabilizer at the NVST,large scale wobble motion is present during the spatial scanning,whose instantaneous amplitude can reach 1.3′′due to the Earth’s atmosphere and the precision of the telescope guiding system,and seriously decreases the spatial resolution of 2D spatial maps composed with scanned spectra.We make the following effort to resolve this problem：the imaging system（e.g.,the Ti O-band）is used to record and detect the displacement vectors of solar image motion during the raster scan,in both the slit and scanning directions.The spectral data（e.g.,the Hαline）which are originally obtained in time sequence are corrected and re-arranged in space according to those displacement vectors.Raster scans are carried out in several active regions with different seeing conditions（two rasters are illustrated in this paper）.Given a certain spatial sampling and temporal resolution,the spatial resolution of the composed 2D map could be close to that of the slit-jaw image.The resulting quality after correction is quantitatively evaluated with two methods.A physical quantity,such as the line-of-sight velocities in multiple layers of the solar atmosphere,is also inferred from the re-arranged spectrum,demonstrating the advantage of this technique.展开更多
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device（CCD） cameras for acquiring spectra. Stabilit...The Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device（CCD） cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2 nd Version（RTS2） is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-frameworkbased control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.展开更多
Cognitive dysfunction in patients with chronic hepatitis C virus(HCV) infection is a distinct form of minimal hepatic encephalopathy(MHE). In fact, the majority of HCV-positive patients, irrespective of the grading of...Cognitive dysfunction in patients with chronic hepatitis C virus(HCV) infection is a distinct form of minimal hepatic encephalopathy(MHE). In fact, the majority of HCV-positive patients, irrespective of the grading of liver fibrosis, display alterations of verbal learning, attention, executive function, and memory when they are evaluated by suitable neuropsychological tests. Similarities between the cognitive dysfunction of HCV patients and MHE of patients with different etiologies are unclear. It is also unknown how the metabolic alterations of advanced liver diseases interact with the HCV-induced cognitive dysfunction, and whether these alterations are reversed by antiviral therapies. HCV replication in the brain may play a role in the pathogenesis of neuroinflammation. HCV-related brain dysfunction may be associated with white matter neuronal loss, alterations of association tracts and perfusion. It is unclear to what extent, in patients with cirrhosis, HCV triggers an irreversible neurodegenerative brain damage. New insights on this issue will be provided by longitudinal studies using the protocols established by the diagnostic and statistical manual of mental disorders fifth edition for cognitive disorders. The domains to be evaluated are complex attention; executive functions; learning and memory; perceptual motor functions; social cognition. These evaluations should be associated with fluorodeoxyglucose positron emission tomography and magnetic resonance imaging(MRI) protocols for major cognitive disorders including magnetic resonance spectroscopy, diffusion tensor imaging, magnetic resonance perfusion, and functional MRI. Also, the characteristics of portal hypertension, including the extent of liver blood flow and the type of portal shunts, should be evaluated.展开更多
Potentially harmful cyanobacterial blooms are an emerging environmental concern in freshwater bodies worldwide. Cyanobacterial blooms are generally caused by high nutrient inputs and warm, still waters and have been a...Potentially harmful cyanobacterial blooms are an emerging environmental concern in freshwater bodies worldwide. Cyanobacterial blooms are generally caused by high nutrient inputs and warm, still waters and have been appearing with increasing frequency in water bodies used for drinking water supply and recreation, a problem which will likely worsen with a warming climate. Cyanobacterial blooms are composed of genera with known biological pigments and can be distinguished and analyzed via hyperspectral image collection technology such as remote sensing by satellites, airplanes, and drones. Here, we utilize hyperspectral microscopy and imaging spectroscopy to charac</span><u><span style="font-family:Verdana;">t</span></u><span style="font-family:Verdana;">erize and differentiate several important bloom-forming cyanobacteria genera obtained in the field during active research programs conducted by US Geological Survey and from commercial sources. Many of the cyanobacteria genera showed differences in their spectra that may be used to identify and predict their occurrence, including peaks and valleys in spectral reflectance. </span><span><span style="font-family:Verdana;">Because certain cyanobacteria, such as </span><i><span style="font-family:Verdana;">Cylindrospermum</span></i><span style="font-family:Verdana;"> or </span><i><span style="font-family:Verdana;">Dolichospe</span></i></span><i><span style="font-family:Verdana;">rmum</span></i><span style="font-family:Verdana;">, are more prone to produce cyanotoxins than others, the ability to different</span><span style="font-family:Verdana;">iate these species may help target high priority waterbodies for sampl</span><span style="font-family:Verdana;">ing. These spectra may also be used to prioritize restoration and research efforts </span><span style="font-family:Verdana;">to control cyanobacterial harmful algal blooms (CyanoHABs) and improv</span><span style="font-family:Verdana;">e water quality for aquatic life and humans alike.展开更多
Spectroscopic characterization of CO activation on multiple metal-containing catalysts remains an important and challenging goal for identifying the structure and nature of active site in many industrial processes suc...Spectroscopic characterization of CO activation on multiple metal-containing catalysts remains an important and challenging goal for identifying the structure and nature of active site in many industrial processes such as Fischer-Tropsch chemistry and alcohol synthesis.Here,we use mass-selected photoelectron velocity-map imaging spectroscopy and quantum chemical calculations to study the reactions of CO molecules with several heterobinuclear transition metal-iron clusters M-Fe(M=Ti,V,Cr).The mass spectra reveal the favorable formation of MFe(CO)_(4)^(-)with relatively high thermodynamic stability.The MFe(CO)_(4)^(-)(M=Ti,V,Cr) complexes are established to have a metal-Fe bonded M-Fe(CO)_(4) structure with C_(3 v) geometry.While the positive charge and unpaired electrons are mainly located on the M atom,the natural charge of Fe(CO)_(4) is about-2 e.The MFe(CO)_(4)^(-)(M=Ti,V,Cr) can be seen as being formed via the interactions between the M^(+)fragment and the [Fe(CO)_(4)]^(2-)core,which satisfies the 18-electron rule.The CO molecules are remarkably activated in these MFe(CO)_(4)^(-).These results shed insight into the structure-reactivity relationship of heterobinuclear transition metal carbonyls and would have important implications for understanding of CO activation on alloy surfaces.展开更多
From 2011 to 2021,LAMOST has released a total of 76,167 quasar data.We try to search for gravitationally lensed QSOs by limiting coordinate differences and redshift differences of these QSOs.The name,brightness,spectr...From 2011 to 2021,LAMOST has released a total of 76,167 quasar data.We try to search for gravitationally lensed QSOs by limiting coordinate differences and redshift differences of these QSOs.The name,brightness,spectrum,photometry and other information of each QSO will be visually checked carefully.Special attention should be paid to check whether there are groups of galaxies,gravitationally lensed arcs,Einstein crosses,or Einstein rings near the QSOs.Through careful selection,we select LAMOST J160603.01+290050.8(A)and LAMOST J160602.81+290048.7(B)as a candidate and perform an initial analysis.Components A and B are336 apart and they display blue during photometric observations.The redshift values of components A and B are0.2%different,their Gaia_g values are 1.3%different,and their ugriz values are 1.0%or less different.For the spectra covering from 3690 to 9100?,the emission lines of C II,Mg,Hγ,OⅢ,and Hβare present for both components A and B and the ratio of flux(B)to flux(A)from LAMOST is basically a constant,around 2.2.However,no galaxies have been found between components A and B.Inada et al.identified them as binary quasars.But we accidentally find a galaxy group near components A and B.If the center of dark matter in the galaxy group is at the center between components A and B,components A and B are probably gravitationally lensed QSOs.We estimate that the Einstein mass is 1.46×10^(11)M_⊙and the total mass of the lens is1.34×10^(13)M_⊙.The deflection angle is 197 at positions A and B and the velocity dispersion is 261 km s^(-1).Theoretically,this candidate could be a pair of fold images of a strong lensing system by a galaxy group,and we will investigate the possibility when the redshifts of nearby galaxies are available.展开更多
Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications.Here we review recent results on the Raman spectroscopy and imaging of graphene.We show ...Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications.Here we review recent results on the Raman spectroscopy and imaging of graphene.We show that Raman spectroscopy and imaging can be used as a quick and unambiguous method to determine the number of graphene layers.The strong Raman signal of single layer graphene compared to graphite is explained by an interference enhancement model.We have also studied the effect of substrates,the top layer deposition,the annealing process,as well as folding(stacking order)on the physical and electronic properties of graphene.Finally,Raman spectroscopy of epitaxial graphene grown on a SiC substrate is presented and strong compressive strain on epitaxial graphene is observed.The results presented here are highly relevant to the application of graphene in nano-electronic devices and help in developing a better understanding of the physical and electronic properties of graphene.展开更多
Terahertz(THz)technology offers novel opportunities in biology and medicine,thanks to the unique features of THzwave interactions with tissues and cells.Among them,we particularly notice strong sensitivity of THz wave...Terahertz(THz)technology offers novel opportunities in biology and medicine,thanks to the unique features of THzwave interactions with tissues and cells.Among them,we particularly notice strong sensitivity of THz waves to the tissue water,as a medium for biochemical reactions and a main endogenous marker for THz spectroscopy and imaging.Tissues of the brain have an exceptionally high content of water.This factor,along with the features of the structural organization and biochemistry of neuronal and glial tissues,makes the brain an exciting subject to study in the THz range.In this paper,progress and prospects of THz technology in neurodiagnostics are overviewed,including diagnosis of neurodegenerative disease,myelin deficit,tumors of the central nervous system(with an emphasis on brain gliomas),and traumatic brain injuries.Fundamental and applied challenges in study of the THz-wave–brain tissue interactions and development of the THz biomedical tools and systems for neurodiagnostics are discussed.展开更多
We introduce a novel method to accurately extract the optical parameters in terahertz reflection imaging. Our method builds on standard self-referencing methods using the reflected signal from the bottom of the imagin...We introduce a novel method to accurately extract the optical parameters in terahertz reflection imaging. Our method builds on standard self-referencing methods using the reflected signal from the bottom of the imaging window material to further compensate for time-dependent system fluctuations and position-dependent variation in the window thickness. Our proposed method not only improves the accuracy, but also simplifies the imaging procedure and reduces measurement times.展开更多
A millimeter wave solid state source—far infrared laser combined interferometer system(MFCI)consisting of a three-channel 890 GHz hydrogen cyanide(HCN)laser interferometer and a threechannel 340 GHz solid state sourc...A millimeter wave solid state source—far infrared laser combined interferometer system(MFCI)consisting of a three-channel 890 GHz hydrogen cyanide(HCN)laser interferometer and a threechannel 340 GHz solid state source interferometer(SSI)is developed for real-time line-integrated electron density feedback and electron density profile of the EXL-50 spherical tokamak device.The interferometer system is a Mach–Zehnder type,with all probe-channels measured vertically,covering the plasma magnetic axis to the outermost closed magnetic plane.The HCN laser interferometer uses an HCN laser with a frequency of 890 GHz as a light source and modulates a100 k Hz beat signal by a rotating grating,giving a temporal resolution of 10μs.The SSI uses two independent 340 GHz solid-state diode sources as the light source,the frequency of the two sources is adjustable,and the temporal resolution of SSI can reach 1μs by setting the frequency difference of the two lasers at 1 MHz.The main optical path of the two interferometers is compactly installed on a set of double-layer optical platform directly below EXL-50.Dual optical path design using corner cube reflectors avoids the large support structures.Collinear the probebeams of two wavelengths,then the phase error caused by vibration can be compensated.At present,the phase noise of the HCN Interferometer is 0.08 rad,corresponding to a line-integrated electron density of 0.88×10^(17)m^(-2),one channel of measuring result was obtained by the MFCI system,and the highest density measured is about 0.7×10^(19)m^(-2).展开更多
Searching for effective biomarkers is one of the most challenging tasks in the research ？eld of Autism Spectrum Disorder（ASD）. Magnetic resonance imaging（MRI） provides a non-invasive and powerful tool for investi...Searching for effective biomarkers is one of the most challenging tasks in the research ？eld of Autism Spectrum Disorder（ASD）. Magnetic resonance imaging（MRI） provides a non-invasive and powerful tool for investigating changes in the structure, function, maturation,connectivity, and metabolism of the brain of children with ASD. Here, we review the more recent MRI studies in young children with ASD, aiming to provide candidate biomarkers for the diagnosis of childhood ASD. The review covers structural imaging methods, diffusion tensor imaging, resting-state functional MRI, and magnetic resonance spectroscopy. Future advances in neuroimaging techniques, as well as cross-disciplinary studies and largescale collaborations will be needed for an integrated approach linking neuroimaging, genetics, and phenotypic data to allow the discovery of new, effective biomarkers.展开更多
Recent studies have demonstrated a new role for Klf10, a Krüppel-like transcription factor, in skeletal muscle, specifically relating to mitochondrial function. Thus, it was of interest to analyze additional tiss...Recent studies have demonstrated a new role for Klf10, a Krüppel-like transcription factor, in skeletal muscle, specifically relating to mitochondrial function. Thus, it was of interest to analyze additional tissues that are highly reliant on optimal mitochondrial function such as the cerebellum and to decipher the role of Klf10 in the functional and structural properties of this brain region. In vivo (magnetic resonance imaging and localized spectroscopy, behavior analysis) and in vitro (histology, spectroscopy analysis, enzymatic activity) techniques were applied to comprehensively assess the cerebellum of wild type (WT) and Klf10 knockout (KO) mice. Histology analysis and assessment of locomotion revealed no significant difference in Klf10 KO mice. Diffusion and texture results obtained using MRI revealed structural changes in KO mice characterized as defects in the organization of axons. These modifications may be explained by differences in the levels of specific metabolites (myo-inositol, lactate) within the KO cerebellum. Loss of Klf10 expression also led to changes in mitochondrial activity as reflected by a significant increase in the activity of citrate synthase, complexes I and IV. In summary, this study has provided evidence that Klf10 plays an important role in energy production and mitochondrial function in the cerebellum.展开更多
Correlation signal processing of optical threedimensional(x,y,t)data can produce super-resolution images.The second-order cross-correlation function XC2 has been documented to produce super-resolution imaging with sta...Correlation signal processing of optical threedimensional(x,y,t)data can produce super-resolution images.The second-order cross-correlation function XC2 has been documented to produce super-resolution imaging with static and blinking emitters but not for diffusing emitters.Here,we both analytically and numerically demonstrate cross-correlation analysis for diffusing particles.We then expand our fluorescence correlation spectroscopy super-resolution optical fluctuation imaging(fcsSOFI)analysis to use cross-correlation as a postprocessing computational technique to extract both dynamic and structural information on particle diffusion in nanoscale structures simultaneously.Cross-correlation maintains the same super-resolution as auto-correlation while also increasing the sampling rates to reduce aliasing for spatial information in both simulated and experimental data.Our work demonstrates how fcsSOFI with cross-correlation can be a powerful signal-processing tool to resolve the nanoscale dynamics and structure in samples relevant to biological and soft materials.展开更多
基金supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2023R196),Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.
文摘Pedo-spectroscopy has the potential to provide valuable information about soil physical,chemical,and biological properties.Nowadays,wemay predict soil properties usingVNIRfield imaging spectra(IS)such as Prisma satellite data or laboratory spectra(LS).The primary goal of this study is to investigate machine learning models namely Partial Least Squares Regression(PLSR)and Support Vector Regression(SVR)for the prediction of several soil properties,including clay,sand,silt,organic matter,nitrate NO3-,and calcium carbonate CaCO_(3),using five VNIR spectra dataset combinations(%IS,%LS)as follows:C1(0%IS,100%LS),C2(20%IS,80%LS),C3(50%IS,50%LS),C4(80%IS,20%LS)and C5(100%IS,0%LS).Soil samples were collected at bare soils and at the upper(0–30 cm)layer.The data set has been split into a training dataset 80%of the collected data(n=248)and a validation dataset 20%of the collected data(n=61).The proposed PLSR and SVR models were trained then tested for each dataset combination.According to our results,SVR outperforms PLSR for both:C1(0%IS,100%LS)and C5(100%IS,0%LS).For Soil Organic Matter(SOM)prediction,it achieves(R^(2)=0.79%,RMSE=1.42%)and(R^(2)=0.76%,RMSE=1.3%),respectively.The data fusion has improved the soil property prediction.The highest improvement was obtained for the SOM property(R^(2)=0.80%,RMSE=1.39)when using the SVR model and applying the second Combination C2(20% of IS and 80%LS).
基金supported by China’s first Asteroid exploration program and China National Space Administration(CNSA)was also funded by the National Natural Science Foundation of China (NSFC,Grant No.12373068)。
文摘The surface particle size and distribution characteristics of celestial bodies (e.g.,the Moon,asteroids,etc.) will affect the interpretation of hyperspectral remote sensing data and the implementation of sampling missions.Currently,the estimation of the surface particle sizes is mainly focusing on interpreting the thermal inertia with the infrared spectral data from ground-based or space telescopes,but this method show distinct errors compared with the imaging results of the orbiter.By analyzing some thermal infrared spectral data,a relationship between the particle sizes of the main rockforming minerals (e.g.pyroxene,feldspar,olivine) and the slopes of their thermal infrared spectrum was found.Based on this relationship,a preliminary model for estimating the grain sizes (~30–300μm) of lunar or S-type asteroids’surfaces which are silicate minerals dominated was established,and the correlation coefficients (R^(2)) for most of the rock-forming minerals were better than 90%.Six observational datasets of natural lunar and terrestrial samples are used to validate the model,and the results show a systematical overestimation of the ground-truth particle sizes,the potential causes are analyzed and an additional correction is used to eliminate the overestimation of the particle size prediction.These results are expected to provide guidance for interpretation of lunar and S-type asteroid surface sampling and spectral data.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2021QB215)the National Natural Science Foundation of China(Nos.22273101,22125303,92061203,21327901,and 22288201)+2 种基金Dalian Institute of Chemical Physics(No.DICP I202437)the Talent Induction Program for Youth Innovation Teams in Colleges and Universities of Shandong Province(No.2022-2024)the Talent Introduction Research Start-up Funds of Ludong University(No.20212026)。
文摘A series of heteronuclear yttrium-nickel monoxide carbonyl complexes YNiO(CO)_(n)^(-)(n=1-5)were generated in a pulsed-laser vaporization source and characterized by mass-selected photoelectron velocity-map spectroscopy combined with theoretical calculations.CO ligand-mediated reactivity in CO oxidation of yttrium-nickel monoxide carbonyl complexes was experimentally and theoretically identified.During the consecutive CO adsorption,aμ^(2)-O linear structure was most favorable for YNiO(CO)_(n)^(-)(n=1,2),then a structure in which the terminal O was bonded to the Y atom became favored for YNiO(CO)_(3)^(-),and finally a structure bearing a CO_(2)moiety was most favorable for YNiO(CO)_(n)^(-)(n=4,5).Theoretical calculations indicated that the Ni atom acted as an electron acceptor and accumulated electron density at n≤3,and then served as an electron donor along with the Y atom to contribute electron density in the rearrangement that accompanied CO oxidation at n>3.
基金Project supported by the State Key Program of National Natural Science of China (Grant No. 40537031)National High Technology Research and Development Program of China (Grant No. 2006AA12Z152)+1 种基金the National Natural Science Foundation of China (Grant Nos. 40875013,40375010 and 60278019)the Science and Technology Plan Foundation of Shaanxi Province,China(Grant No. 2005K04-G18)
文摘The static large field of the view polarization interference imaging spectrometer is based on the modified Savart polariseope. There appears a dispersion between the ordinary ray and extraordinary ray when light passes through the modified Savart polariscope. The dispersion greatly influences the intensities and the results of the interferogram and target image in the static large field of the view polarization interference imaging spectrometer. At the same time, the incident angle determines the dispersion. When the light goes through the modified Savart polariscope, the dispersion occurs in the left plate, the half-wave plate and the right plate of the modified Savart polariscope. Using the extension of Shell＇s law, the dispersion in the crystal is theoretically calculated and numerically simulated separately. The relationship curve between incident angle and the dispersion is obtained by simulation.
文摘Propagating disturbances（PDs） were studied along an active region loop using simultaneous imaging and spectroscopy. An image sequence recorded in the Fe Ⅸ/Fe X 171 channel, from TRACE and spectral data in the Si Ⅻ 520.6 line obtained from CDS/SOHO, are analyzed. A space-time map constructed from the TRACE image sequence shows the presence of PDs close to the loop foot point propagating with an apparent speed of 39 km s-1. The periodicity was found to be 5.4 min.The corresponding spectroscopic data from CDS, at a location away from the foot point, show oscillations in all three line parameters roughly at the same period. At locations farther from the foot point, the line width oscillation seems to disappear while the Doppler velocity oscillation becomes prominent. We attribute this to the signature of propagating slow waves that get affected by flows/other events close to the foot point. Spectral line profiles do not show much asymmetry, however, it is difficult to infer anything due to the broadened Gaussian shape of the CDS line profiles.
基金the Indian Space Research Organization,Bangalore,for funding under the Ch-1 AO Research Project(ISRO/SSPO/CH-1/2016–2019)to carry out this research work。
文摘The Mare Moscoviense is an astonishing rare flatland multi-ring basin and one of the recognizable mare regions on the Moon's farside.The mineralogical,chronological,topographical and morphological studies of the maria surface of the Moon provide a primary understanding of the origin and evolution of the mare provinces.In this study,the Chandrayaan-1 M^(3)data have been employed to prepare optical maturity index,FeO and TiO^(2)concentration,and standard band ratio map to detect the mafic indexes like olivine and pyroxene minerals.The crater size frequency distribution method has been applied to LROC WAC data to obtain the absolute model ages of the Moscoviense basin.The four geological unit ages were observed as 3.57 Ga(U-2),3.65 Ga(U-1),3.8 Ga(U-3)and 3.92 Ga(U-4),which could have been formed between the Imbrian and Nectarian epochs.The M^(3)imaging and reflectance spectral parameters were used to reveal the minerals like pyroxene,olivine,ilmenite,plagioclase,orthopyroxene-olivine-spinel lithology,and olivine-pyroxene mixtures present in the gabbroic basalt,anorthositic and massive ilmenite rocks,and validated with the existing database.The results show that the Moscoviense basin is dominated by intermediate TiO^(2)basalts that derived from olivine-ilmenite-pyroxene cumulate depths ranging from 200 to 500 km between 3.5 Ga and 3.6 Ga.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11773072, 11573012 and 11473064)
文摘In this paper we illustrate the technique used by the New Vacuum Solar Telescope（NVST）to increase the spatial resolution of two-dimensional（2D）solar spectroscopy observations involving two dimensions of space and one of wavelength.Without an image stabilizer at the NVST,large scale wobble motion is present during the spatial scanning,whose instantaneous amplitude can reach 1.3′′due to the Earth’s atmosphere and the precision of the telescope guiding system,and seriously decreases the spatial resolution of 2D spatial maps composed with scanned spectra.We make the following effort to resolve this problem：the imaging system（e.g.,the Ti O-band）is used to record and detect the displacement vectors of solar image motion during the raster scan,in both the slit and scanning directions.The spectral data（e.g.,the Hαline）which are originally obtained in time sequence are corrected and re-arranged in space according to those displacement vectors.Raster scans are carried out in several active regions with different seeing conditions（two rasters are illustrated in this paper）.Given a certain spatial sampling and temporal resolution,the spatial resolution of the composed 2D map could be close to that of the slit-jaw image.The resulting quality after correction is quantitatively evaluated with two methods.A physical quantity,such as the line-of-sight velocities in multiple layers of the solar atmosphere,is also inferred from the re-arranged spectrum,demonstrating the advantage of this technique.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFE0100300)the Joint Research Fund in Astronomy(Grant Nos.U1531132,U1631129 and U1231205)under cooperative agreement between the National Natural Science Foundation of China(NSFC)+1 种基金the Chinese Academy of Sciences(CAS)the National Natural Science Foundation of China(Grant Nos.11603044,11703044,11503042,11403009and 11463003)
文摘The Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device（CCD） cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2 nd Version（RTS2） is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-frameworkbased control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.
文摘Cognitive dysfunction in patients with chronic hepatitis C virus(HCV) infection is a distinct form of minimal hepatic encephalopathy(MHE). In fact, the majority of HCV-positive patients, irrespective of the grading of liver fibrosis, display alterations of verbal learning, attention, executive function, and memory when they are evaluated by suitable neuropsychological tests. Similarities between the cognitive dysfunction of HCV patients and MHE of patients with different etiologies are unclear. It is also unknown how the metabolic alterations of advanced liver diseases interact with the HCV-induced cognitive dysfunction, and whether these alterations are reversed by antiviral therapies. HCV replication in the brain may play a role in the pathogenesis of neuroinflammation. HCV-related brain dysfunction may be associated with white matter neuronal loss, alterations of association tracts and perfusion. It is unclear to what extent, in patients with cirrhosis, HCV triggers an irreversible neurodegenerative brain damage. New insights on this issue will be provided by longitudinal studies using the protocols established by the diagnostic and statistical manual of mental disorders fifth edition for cognitive disorders. The domains to be evaluated are complex attention; executive functions; learning and memory; perceptual motor functions; social cognition. These evaluations should be associated with fluorodeoxyglucose positron emission tomography and magnetic resonance imaging(MRI) protocols for major cognitive disorders including magnetic resonance spectroscopy, diffusion tensor imaging, magnetic resonance perfusion, and functional MRI. Also, the characteristics of portal hypertension, including the extent of liver blood flow and the type of portal shunts, should be evaluated.
文摘Potentially harmful cyanobacterial blooms are an emerging environmental concern in freshwater bodies worldwide. Cyanobacterial blooms are generally caused by high nutrient inputs and warm, still waters and have been appearing with increasing frequency in water bodies used for drinking water supply and recreation, a problem which will likely worsen with a warming climate. Cyanobacterial blooms are composed of genera with known biological pigments and can be distinguished and analyzed via hyperspectral image collection technology such as remote sensing by satellites, airplanes, and drones. Here, we utilize hyperspectral microscopy and imaging spectroscopy to charac</span><u><span style="font-family:Verdana;">t</span></u><span style="font-family:Verdana;">erize and differentiate several important bloom-forming cyanobacteria genera obtained in the field during active research programs conducted by US Geological Survey and from commercial sources. Many of the cyanobacteria genera showed differences in their spectra that may be used to identify and predict their occurrence, including peaks and valleys in spectral reflectance. </span><span><span style="font-family:Verdana;">Because certain cyanobacteria, such as </span><i><span style="font-family:Verdana;">Cylindrospermum</span></i><span style="font-family:Verdana;"> or </span><i><span style="font-family:Verdana;">Dolichospe</span></i></span><i><span style="font-family:Verdana;">rmum</span></i><span style="font-family:Verdana;">, are more prone to produce cyanotoxins than others, the ability to different</span><span style="font-family:Verdana;">iate these species may help target high priority waterbodies for sampl</span><span style="font-family:Verdana;">ing. These spectra may also be used to prioritize restoration and research efforts </span><span style="font-family:Verdana;">to control cyanobacterial harmful algal blooms (CyanoHABs) and improv</span><span style="font-family:Verdana;">e water quality for aquatic life and humans alike.
基金supported by the National Natural Science Foundation of China (21688102, 21873097, and 92061203)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (CAS)(2020187)+3 种基金the Strategic Priority Research Program of CAS (XDB17000000)CAS (GJJSTD20190002)the International Partnership Program of CAS (121421KYSB20170012)the K.C.Wong Education Foundation (GJTD-2018-06)。
文摘Spectroscopic characterization of CO activation on multiple metal-containing catalysts remains an important and challenging goal for identifying the structure and nature of active site in many industrial processes such as Fischer-Tropsch chemistry and alcohol synthesis.Here,we use mass-selected photoelectron velocity-map imaging spectroscopy and quantum chemical calculations to study the reactions of CO molecules with several heterobinuclear transition metal-iron clusters M-Fe(M=Ti,V,Cr).The mass spectra reveal the favorable formation of MFe(CO)_(4)^(-)with relatively high thermodynamic stability.The MFe(CO)_(4)^(-)(M=Ti,V,Cr) complexes are established to have a metal-Fe bonded M-Fe(CO)_(4) structure with C_(3 v) geometry.While the positive charge and unpaired electrons are mainly located on the M atom,the natural charge of Fe(CO)_(4) is about-2 e.The MFe(CO)_(4)^(-)(M=Ti,V,Cr) can be seen as being formed via the interactions between the M^(+)fragment and the [Fe(CO)_(4)]^(2-)core,which satisfies the 18-electron rule.The CO molecules are remarkably activated in these MFe(CO)_(4)^(-).These results shed insight into the structure-reactivity relationship of heterobinuclear transition metal carbonyls and would have important implications for understanding of CO activation on alloy surfaces.
基金provided by the National Development and Reform Commissionthe support of the National Natural Science Foundation of China(NSFC,11803004)+2 种基金Yunnan Province Youth Talent Project(2019182)the support by NSFC through grant No.12203011Yunnan provincial Department of Science and Technology through grant No.202101BA070001-261。
文摘From 2011 to 2021,LAMOST has released a total of 76,167 quasar data.We try to search for gravitationally lensed QSOs by limiting coordinate differences and redshift differences of these QSOs.The name,brightness,spectrum,photometry and other information of each QSO will be visually checked carefully.Special attention should be paid to check whether there are groups of galaxies,gravitationally lensed arcs,Einstein crosses,or Einstein rings near the QSOs.Through careful selection,we select LAMOST J160603.01+290050.8(A)and LAMOST J160602.81+290048.7(B)as a candidate and perform an initial analysis.Components A and B are336 apart and they display blue during photometric observations.The redshift values of components A and B are0.2%different,their Gaia_g values are 1.3%different,and their ugriz values are 1.0%or less different.For the spectra covering from 3690 to 9100?,the emission lines of C II,Mg,Hγ,OⅢ,and Hβare present for both components A and B and the ratio of flux(B)to flux(A)from LAMOST is basically a constant,around 2.2.However,no galaxies have been found between components A and B.Inada et al.identified them as binary quasars.But we accidentally find a galaxy group near components A and B.If the center of dark matter in the galaxy group is at the center between components A and B,components A and B are probably gravitationally lensed QSOs.We estimate that the Einstein mass is 1.46×10^(11)M_⊙and the total mass of the lens is1.34×10^(13)M_⊙.The deflection angle is 197 at positions A and B and the velocity dispersion is 261 km s^(-1).Theoretically,this candidate could be a pair of fold images of a strong lensing system by a galaxy group,and we will investigate the possibility when the redshifts of nearby galaxies are available.
文摘Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications.Here we review recent results on the Raman spectroscopy and imaging of graphene.We show that Raman spectroscopy and imaging can be used as a quick and unambiguous method to determine the number of graphene layers.The strong Raman signal of single layer graphene compared to graphite is explained by an interference enhancement model.We have also studied the effect of substrates,the top layer deposition,the annealing process,as well as folding(stacking order)on the physical and electronic properties of graphene.Finally,Raman spectroscopy of epitaxial graphene grown on a SiC substrate is presented and strong compressive strain on epitaxial graphene is observed.The results presented here are highly relevant to the application of graphene in nano-electronic devices and help in developing a better understanding of the physical and electronic properties of graphene.
基金The work was supported by the Russian Science Foundation,Project#22-22-00596.
文摘Terahertz(THz)technology offers novel opportunities in biology and medicine,thanks to the unique features of THzwave interactions with tissues and cells.Among them,we particularly notice strong sensitivity of THz waves to the tissue water,as a medium for biochemical reactions and a main endogenous marker for THz spectroscopy and imaging.Tissues of the brain have an exceptionally high content of water.This factor,along with the features of the structural organization and biochemistry of neuronal and glial tissues,makes the brain an exciting subject to study in the THz range.In this paper,progress and prospects of THz technology in neurodiagnostics are overviewed,including diagnosis of neurodegenerative disease,myelin deficit,tumors of the central nervous system(with an emphasis on brain gliomas),and traumatic brain injuries.Fundamental and applied challenges in study of the THz-wave–brain tissue interactions and development of the THz biomedical tools and systems for neurodiagnostics are discussed.
基金Research Grants Council of Hong Kong(415313,14205514)Direct Grant,Chinese University of Hong Kong
文摘We introduce a novel method to accurately extract the optical parameters in terahertz reflection imaging. Our method builds on standard self-referencing methods using the reflected signal from the bottom of the imaging window material to further compensate for time-dependent system fluctuations and position-dependent variation in the window thickness. Our proposed method not only improves the accuracy, but also simplifies the imaging procedure and reduces measurement times.
基金supported by the National MCF Energy R&D Program(Nos.2019YFE03040003 and 2017YFE0301205)supported in part by Key Program of Research and Development of Hefei Science Center,CAS(No.2019HSC-KPRD001)partly supported by the Collaborative Research Program of the Research Institute for Applied Mechanics,Kyushu University.
文摘A millimeter wave solid state source—far infrared laser combined interferometer system(MFCI)consisting of a three-channel 890 GHz hydrogen cyanide(HCN)laser interferometer and a threechannel 340 GHz solid state source interferometer(SSI)is developed for real-time line-integrated electron density feedback and electron density profile of the EXL-50 spherical tokamak device.The interferometer system is a Mach–Zehnder type,with all probe-channels measured vertically,covering the plasma magnetic axis to the outermost closed magnetic plane.The HCN laser interferometer uses an HCN laser with a frequency of 890 GHz as a light source and modulates a100 k Hz beat signal by a rotating grating,giving a temporal resolution of 10μs.The SSI uses two independent 340 GHz solid-state diode sources as the light source,the frequency of the two sources is adjustable,and the temporal resolution of SSI can reach 1μs by setting the frequency difference of the two lasers at 1 MHz.The main optical path of the two interferometers is compactly installed on a set of double-layer optical platform directly below EXL-50.Dual optical path design using corner cube reflectors avoids the large support structures.Collinear the probebeams of two wavelengths,then the phase error caused by vibration can be compensated.At present,the phase noise of the HCN Interferometer is 0.08 rad,corresponding to a line-integrated electron density of 0.88×10^(17)m^(-2),one channel of measuring result was obtained by the MFCI system,and the highest density measured is about 0.7×10^(19)m^(-2).
文摘Searching for effective biomarkers is one of the most challenging tasks in the research ？eld of Autism Spectrum Disorder（ASD）. Magnetic resonance imaging（MRI） provides a non-invasive and powerful tool for investigating changes in the structure, function, maturation,connectivity, and metabolism of the brain of children with ASD. Here, we review the more recent MRI studies in young children with ASD, aiming to provide candidate biomarkers for the diagnosis of childhood ASD. The review covers structural imaging methods, diffusion tensor imaging, resting-state functional MRI, and magnetic resonance spectroscopy. Future advances in neuroimaging techniques, as well as cross-disciplinary studies and largescale collaborations will be needed for an integrated approach linking neuroimaging, genetics, and phenotypic data to allow the discovery of new, effective biomarkers.
文摘Recent studies have demonstrated a new role for Klf10, a Krüppel-like transcription factor, in skeletal muscle, specifically relating to mitochondrial function. Thus, it was of interest to analyze additional tissues that are highly reliant on optimal mitochondrial function such as the cerebellum and to decipher the role of Klf10 in the functional and structural properties of this brain region. In vivo (magnetic resonance imaging and localized spectroscopy, behavior analysis) and in vitro (histology, spectroscopy analysis, enzymatic activity) techniques were applied to comprehensively assess the cerebellum of wild type (WT) and Klf10 knockout (KO) mice. Histology analysis and assessment of locomotion revealed no significant difference in Klf10 KO mice. Diffusion and texture results obtained using MRI revealed structural changes in KO mice characterized as defects in the organization of axons. These modifications may be explained by differences in the levels of specific metabolites (myo-inositol, lactate) within the KO cerebellum. Loss of Klf10 expression also led to changes in mitochondrial activity as reflected by a significant increase in the activity of citrate synthase, complexes I and IV. In summary, this study has provided evidence that Klf10 plays an important role in energy production and mitochondrial function in the cerebellum.
基金NIH NIGMS Grant R35GM142466 for financial support of this work.
文摘Correlation signal processing of optical threedimensional(x,y,t)data can produce super-resolution images.The second-order cross-correlation function XC2 has been documented to produce super-resolution imaging with static and blinking emitters but not for diffusing emitters.Here,we both analytically and numerically demonstrate cross-correlation analysis for diffusing particles.We then expand our fluorescence correlation spectroscopy super-resolution optical fluctuation imaging(fcsSOFI)analysis to use cross-correlation as a postprocessing computational technique to extract both dynamic and structural information on particle diffusion in nanoscale structures simultaneously.Cross-correlation maintains the same super-resolution as auto-correlation while also increasing the sampling rates to reduce aliasing for spatial information in both simulated and experimental data.Our work demonstrates how fcsSOFI with cross-correlation can be a powerful signal-processing tool to resolve the nanoscale dynamics and structure in samples relevant to biological and soft materials.
