This paper proposed a deep-learning-based method to process the scattered field data of transmitting antenna,which is unmeasurable in inverse scattering system because the transmitting and receiving antennas are multi...This paper proposed a deep-learning-based method to process the scattered field data of transmitting antenna,which is unmeasurable in inverse scattering system because the transmitting and receiving antennas are multiplexed.A U-net convolutional neural network(CNN)is used to recover the scattered field data of each transmitting antenna.The numerical results proved that the proposed method can complete the scattered field data at the transmitting antenna which is unable to measure in the actual experiment and can also eliminate the reconstructed error caused by the loss of scattered field data.展开更多
This paper presents a reasonable gridding-parameters extraction method for setting the optimal interpolation nodes in the gridding of scattered observed data. The method can extract optimized gridding parameters based...This paper presents a reasonable gridding-parameters extraction method for setting the optimal interpolation nodes in the gridding of scattered observed data. The method can extract optimized gridding parameters based on the distribution of features in raw data. Modeling analysis proves that distortion caused by gridding can be greatly reduced when using such parameters. We also present some improved technical measures that use human- machine interaction and multi-thread parallel technology to solve inadequacies in traditional gridding software. On the basis of these methods, we have developed software that can be used to grid scattered data using a graphic interface. Finally, a comparison of different gridding parameters on field magnetic data from Ji Lin Province, North China demonstrates the superiority of the proposed method in eliminating the distortions and enhancing gridding efficiency.展开更多
Conventional seismic exploration,mostly based on reflection theory,hardly has accurate imaging results for disaster geologic bodies which have small scale,steep dip,or complex structure.In this paper,we design two typ...Conventional seismic exploration,mostly based on reflection theory,hardly has accurate imaging results for disaster geologic bodies which have small scale,steep dip,or complex structure.In this paper,we design two typical geologic models for analyzing the characteristics of scattered waves in mines for forward modeling by finite difference and apply the equivalent offset migration(EOM)and EOM-based interference stack migration methods to mine prospecting.We focus on the analysis of scatted imaging’s technological superiority to reflection imaging.Research shows:1)scattered imaging can improve fold and make the best of weak scattered information,so it shows better results than post-stack migration imaging and 2)it can utilize the diffraction stack migration method-based ray path theory for mine seismic advanced prediction,so it provides an new efficient imaging method for improving resolution of mine seismic exploration.展开更多
The scattered fields of plane waves in a solid from a cylinder or sphere are critical in determining its acoustic characteristics as well as in engineering applications. This paper investigates the scattered field dis...The scattered fields of plane waves in a solid from a cylinder or sphere are critical in determining its acoustic characteristics as well as in engineering applications. This paper investigates the scattered field distributions of different incident waves created by elastic cylinders embedded in an elastic isotropic medium. Scattered waves, including longitudinal and transverse waves both inside and outside the cylinder, are described with specific modalities under an incident plane wave. A model with a scatterer embedded in a structural steel matrix and filled with aluminum is developed for comparison with the theoretical solution. The frequency of the plane wave ranged from 235 kHz to 2348 kHz, which corresponds to scaling factors from 0.5 to 5. Scattered field distributions in matrix materials blocked by an elastic cylindrical solid have been obtained by simulation or calculated using existing parameters. The simulation results are in good agreement with the theoretical solution, which supports the correctness of the simulation analysis. Furthermore, ultrasonic phased arrays are used to study scattered fields by changing the characteristics of the incident wave. On this foundation, a partial preliminary study of the scattered field distribution of double cylinders in a solid has been carried out, and the scattered field distribution at a given distance has been found to exhibit particular behaviors at different moments. Further studies on directivities and scattered fields are expected to improve the quantification of scattered images in isotropic solid materials by the phased array technique.展开更多
The mass mortality of pond-reared scattered mirror carp, Cyprinus carpio, caused by Thelohanellus kitauei, occurred at fish farms in Sichuan Province, southwest China. Morphological and molecular analyses were supplem...The mass mortality of pond-reared scattered mirror carp, Cyprinus carpio, caused by Thelohanellus kitauei, occurred at fish farms in Sichuan Province, southwest China. Morphological and molecular analyses were supplemented with histological evaluation of infected tissues to better understand the route of infection and the pathological effects of 1". kitauei on the fish host. The intestine of the diseased host was full of large cysts of the myxosporean. The cysts range from 2 cm to 3.6 cm in diameter. Histopathology indicated that T. kitauei first invaded the submucosa of the host intestine and then moved into the mucosa layers with the development of their spores, finally entering into the enteric cavity of the hosts after the disruption of mucosa layers. The pyriform spores of T. kitauei were surrounded by the transparent spore sheath, measuring 25.98/μm±0.95 μm in body length, 8.72 μm±0.51μm body width, and 7.86 μm±0.26 μm in body thickness. The single polar capsule was pyriform, measuring 14.73 μm±0.92μm in length and 6.82 μm±0.45μm in width, with eight to 10 turns of filament coils winding inside. Phylogenetic analysis based on the 18S small-subunit ribosomal DNA sequences indicated that minimal genetic differences were present between T. kitauei samples from South Korea and from China. Close affinity was found between the genus Thelohanellus and Myxobolus. Additionally, two polar capsule nuclei were found at the anterior end of the single polar capsule in spores of T. kitauei stained with hematoxylin and eosin, which suggested the separation of the genus Thelohanellus from Myxobolus.展开更多
A new detection system in scanning electron microscope,which filters in energy and detects the backscattered electrons close to the microscope axis,is described.This technique ameliorates the dependence of the back.sc...A new detection system in scanning electron microscope,which filters in energy and detects the backscattered electrons close to the microscope axis,is described.This technique ameliorates the dependence of the back.scat tering coefficient on atomic number,and suppresses effectively the relief contrast at the same time.Therefore this new method is very suitable to the composition analysis.展开更多
Making rural settlements of Mountainous Regions in Western Sichuan as the study objects and using symbolic statistical methods, then combining the case study of Daofu County, the paper analyzes the negative impact of ...Making rural settlements of Mountainous Regions in Western Sichuan as the study objects and using symbolic statistical methods, then combining the case study of Daofu County, the paper analyzes the negative impact of the scattered rural settlements on infrastructure construction, farmers' income increase and mountain ecological reconstruction in mountainous regions of western Sichuan. The results indicate that economic density is positively related to both rural settlements density (R^2=0.73) and rural population density (R^2=0.77), and it is the same for relationship between towns density and rural settlements density (R^2=0.88) and between towns density and economic density (R^2=0.71), and the scattered distribution pattern of the rural settlements and shortage of economic centers is a major factor to the lagged socioeconomic development. On the eco-economic zoning to Daofu County, the paper indicates the spatial distribution model and the industrial development model of the rural settlements need to be changed, and rural population should be concentrated in larger rural settlements with development of off-farm industries while infrastructure construction is to reinforced.展开更多
For Hermite-Birkhoff interpolation of scattered multidumensional data by radial basis function (?),existence and characterization theorems and a variational principle are proved. Examples include (?)(r)=r^b,Duchon'...For Hermite-Birkhoff interpolation of scattered multidumensional data by radial basis function (?),existence and characterization theorems and a variational principle are proved. Examples include (?)(r)=r^b,Duchon's thin-plate splines,Hardy's multiquadrics,and inverse multiquadrics.展开更多
This paper presents a new deep-reading logging-while-drilling electromagnetic(EM)logging method to detect bed boundaries ahead of bit.Unlike all existing EM logging approaches,the new method is based on the scattered ...This paper presents a new deep-reading logging-while-drilling electromagnetic(EM)logging method to detect bed boundaries ahead of bit.Unlike all existing EM logging approaches,the new method is based on the scattered electric field radiated by a magnetic dipole antenna.By analyzing the characteristics of electric tensor responses in layered formations,optimal look-ahead electric component is selected.The selected scattered field contributes to a large portion of the total field and is strongly sensitive to the boundary position.The measured voltage from the scattered electric component can be tens of times larger than that from the scattered magnetic fields and it attenuates slower.Thus,the detection capability improves significantly.A coaxial open-loop half-circle antenna is then proposed to measure the electric field in logging while drilling environment.A practical tool implementation equipped with two tilted close-loop antennas and two open-loop antennas is further developed for look-ahead application.Numerical results demonstrate that the detection depth of the new look-ahead tool can be up to 40 m under favorable conditions.Compared with current look-ahead logging tools,the new method not only significantly shortens the tool size,but also can recognize the boundary position and azimuth.展开更多
Scattered storage means an item can be stored in multiple inventory bins. The scattered storage assignment problem based on association rules in Kiva mobile fulfillment system is investigated, which aims to decide the...Scattered storage means an item can be stored in multiple inventory bins. The scattered storage assignment problem based on association rules in Kiva mobile fulfillment system is investigated, which aims to decide the pods for each item to put on so as to minimize the number of pods to be moved when picking a batch of orders. This problem is formulated into an integer programming model. A genetic algorithm is developed to solve the large-sized problems. Computational experiments and comparison between the scattered storage strategy and random storage strategy are conducted to evaluate the performance of the model and algorithm.展开更多
We use Radial Basis Functions (RBFs) to reconstruct smooth surfaces from 3D scattered data. An object's surface is defined implicitly as the zero set of an RBF fitted to the given surface data. We propose improveme...We use Radial Basis Functions (RBFs) to reconstruct smooth surfaces from 3D scattered data. An object's surface is defined implicitly as the zero set of an RBF fitted to the given surface data. We propose improvements on the methods of surface reconstruction with radial basis functions. A sparse approximation set of scattered data is constructed by reducing the number of interpolating points on the surface. We present an adaptive method for finding the off-surface normal points. The order of the equation decreases greatly as the number of the off-surface constraints reduces gradually. Experimental results are provided to illustrate that the proposed method is robust and may draw beautiful graphics.展开更多
From July 31 to August I in 2008, a strong thunderstorm process occurred in Neijiang of Sichuan Province, and a strange scattered light- ning strike phenomenon happened in office building of Dongxing Meteorological Bu...From July 31 to August I in 2008, a strong thunderstorm process occurred in Neijiang of Sichuan Province, and a strange scattered light- ning strike phenomenon happened in office building of Dongxing Meteorological Bureau in Neijiang. Through a series of investigations and analyses, we found occurrence reason of the scattered lightning strike and improved lightning protection measures.展开更多
An improved self-organizing feature map (SOFM) neural network is presented to generate rectangular and hexagonal lattic with normal vector attached to each vertex. After the neural network was trained, the whole scatt...An improved self-organizing feature map (SOFM) neural network is presented to generate rectangular and hexagonal lattic with normal vector attached to each vertex. After the neural network was trained, the whole scattered data were divided into sub-regions where classified core were represented by the weight vectors of neurons at the output layer of neural network. The weight vectors of the neurons were used to approximate the dense 3-D scattered points, so the dense scattered points could be reduced to a reasonable scale, while the topological feature of the whole scattered points were remained.展开更多
Solving large radial basis function (RBF) interpolation problem with non-customized methods is computationally expensive and the matrices that occur are typically badly conditioned. In order to avoid these difficult...Solving large radial basis function (RBF) interpolation problem with non-customized methods is computationally expensive and the matrices that occur are typically badly conditioned. In order to avoid these difficulties, we present a fitting based on radial basis functions satisfying side conditions by least squares, although compared with interpolation the method loses some accuracy, it reduces the computational cost largely. Since the fitting accuracy and the non-singularity of coefficient matrix in normal equation are relevant to the uniformity of chosen centers of the fitted RBE we present a choice method of uniform centers. Numerical results confirm the fitting efficiency.展开更多
The time-of-flight enhanced diagnostics(TOFED)neutron spectrometer has been installed in TOFED house,which is a newly-built neutron diagnostic lab outside the EAST experimental hall.The line of sight(LOS)of TOFED is d...The time-of-flight enhanced diagnostics(TOFED)neutron spectrometer has been installed in TOFED house,which is a newly-built neutron diagnostic lab outside the EAST experimental hall.The line of sight(LOS)of TOFED is defined by the collimator going through the 150 cm biological shielding wall,which can reduce background neutrons very effectively for the neutron spectral measurements.The Monte Carlo code MCNP5 is used in the simulations to characterize collimation effects and the radiation safety of the new house.The collimator makes neutron flux almost fully perpendicular to S 1 detectors.In addition,the proportion of scattered neutrons in the LOS of the TOFED is obtained for the measured spectral data interpretation.The simulation results show that the TOFED house satisfies the requirement for the TOFED operations at EAST and gives a safe environment for personnel access during the EAST operation.展开更多
Based on laser radar equations, a Doppler shift model of a laser pulse beam scattered by a rotating arbitrary convex target is reported in this paper. The boundary relations between an incident pulse beam and the dete...Based on laser radar equations, a Doppler shift model of a laser pulse beam scattered by a rotating arbitrary convex target is reported in this paper. The boundary relations between an incident pulse beam and the detected area elements are analyzed by geometric methods. The Doppler shift characteristics of the rotating cone and cylinder are discussed and the difference between the laser pulse beam and the plane wave scattered from the same rotating target is compared accordingly. Numerical simulations show that the Doppler shift is tightly relevant to their dimensions, speeds, and so on. In the same incidence conditions, the pulse beam and plane wave have difference peak values and the same Doppler shift bandwidth. If the waist radius of the pulse beam is larger, the peak value is higher, and the Doppler shifts are proportional to the speed of the rotating target. By virtue of our theoretical model, we probe into the scattered characteristics of the Doppler shifts of a laser pulse beam, which would benefit target identification in national defense.展开更多
Calculations on differential cross sections and spin polarization parameters of elastical electron scattering with Hg atoms are performed for electrons in the energy range from 0.5 to 150eV.Dirac equation is used to d...Calculations on differential cross sections and spin polarization parameters of elastical electron scattering with Hg atoms are performed for electrons in the energy range from 0.5 to 150eV.Dirac equation is used to describe the motion of scattered electrons in the target field,which includes static,exchange and correlation-polarization interactions.The agreement between theory and experiment is generally good.展开更多
In this paper an error in[4]is pointed out and a method for constructingsurface interpolating scattered data points is presented.The main feature of the methodin this paper is that the surface so constructed is polyno...In this paper an error in[4]is pointed out and a method for constructingsurface interpolating scattered data points is presented.The main feature of the methodin this paper is that the surface so constructed is polynomial,which makes the construction simple and the calculation easy.展开更多
A simpler and improved utility approximate point scattered function for thin-film converters currently used in neutron photographic devices is proposed as a correction method to produce clearer,more realistic images.T...A simpler and improved utility approximate point scattered function for thin-film converters currently used in neutron photographic devices is proposed as a correction method to produce clearer,more realistic images.The validity of the model was demonstrated through a simulation experiment.Based on the results,an error analysis was carried out,certain corrections were made to the original model,and the final model achieved a very low relative error in the simulation experiment.The model can also be optimized for quantitative neutron photographic analysis using iterative algorithms to obtain realistic neutron photographic images more quickly.At the end of the article,the model is extended to consider the case of energy spectrum hardening by introducing a temperature correction parameter.展开更多
基金National Natural Science Foundation of China(No.61971036)Fundamental Research Funds for the Central Universities(No.2023CX01011)Beijing Nova Program(No.20230484361)。
文摘This paper proposed a deep-learning-based method to process the scattered field data of transmitting antenna,which is unmeasurable in inverse scattering system because the transmitting and receiving antennas are multiplexed.A U-net convolutional neural network(CNN)is used to recover the scattered field data of each transmitting antenna.The numerical results proved that the proposed method can complete the scattered field data at the transmitting antenna which is unable to measure in the actual experiment and can also eliminate the reconstructed error caused by the loss of scattered field data.
基金partly supported by the Public Geological Survey Project(No.201011039)the National High Technology Research and Development Project of China(No.2007AA06Z134)the 111 Project under the Ministry of Education and the State Administration of Foreign Experts Affairs,China(No.B07011)
文摘This paper presents a reasonable gridding-parameters extraction method for setting the optimal interpolation nodes in the gridding of scattered observed data. The method can extract optimized gridding parameters based on the distribution of features in raw data. Modeling analysis proves that distortion caused by gridding can be greatly reduced when using such parameters. We also present some improved technical measures that use human- machine interaction and multi-thread parallel technology to solve inadequacies in traditional gridding software. On the basis of these methods, we have developed software that can be used to grid scattered data using a graphic interface. Finally, a comparison of different gridding parameters on field magnetic data from Ji Lin Province, North China demonstrates the superiority of the proposed method in eliminating the distortions and enhancing gridding efficiency.
基金supported financially by the National Key Project(Grant No.2008ZX05035)the 973 Program(Grant No. 2009CB219603 and 2007CB209406)the National Natural Science Foundation of China(Grant No.50974081)
文摘Conventional seismic exploration,mostly based on reflection theory,hardly has accurate imaging results for disaster geologic bodies which have small scale,steep dip,or complex structure.In this paper,we design two typical geologic models for analyzing the characteristics of scattered waves in mines for forward modeling by finite difference and apply the equivalent offset migration(EOM)and EOM-based interference stack migration methods to mine prospecting.We focus on the analysis of scatted imaging’s technological superiority to reflection imaging.Research shows:1)scattered imaging can improve fold and make the best of weak scattered information,so it shows better results than post-stack migration imaging and 2)it can utilize the diffraction stack migration method-based ray path theory for mine seismic advanced prediction,so it provides an new efficient imaging method for improving resolution of mine seismic exploration.
基金Supported by National Key R&D Program of China(Grant No.2016YFF0203000)State Key Program of National Natural Science Foundation of China(Grant No.11834008)+5 种基金National Natural Science Foundation of China(Grant Nos.11774167,61571222)Fundamental research funds for the Central Universities(Grant No.020414380001)State Key Laboratory of Acoustics,Chinese Academy of Science(Grant No.SKLA201809)Key Laboratory of Underwater Acoustic Environment,Chinese Academy of Sciences(Grant No.SSHJ-KFKT-1701)AQSIQ technology R&D program(Grant No.2017QK125)Innovative Talents Program of Far East NDT New Technology&Application Forum
文摘The scattered fields of plane waves in a solid from a cylinder or sphere are critical in determining its acoustic characteristics as well as in engineering applications. This paper investigates the scattered field distributions of different incident waves created by elastic cylinders embedded in an elastic isotropic medium. Scattered waves, including longitudinal and transverse waves both inside and outside the cylinder, are described with specific modalities under an incident plane wave. A model with a scatterer embedded in a structural steel matrix and filled with aluminum is developed for comparison with the theoretical solution. The frequency of the plane wave ranged from 235 kHz to 2348 kHz, which corresponds to scaling factors from 0.5 to 5. Scattered field distributions in matrix materials blocked by an elastic cylindrical solid have been obtained by simulation or calculated using existing parameters. The simulation results are in good agreement with the theoretical solution, which supports the correctness of the simulation analysis. Furthermore, ultrasonic phased arrays are used to study scattered fields by changing the characteristics of the incident wave. On this foundation, a partial preliminary study of the scattered field distribution of double cylinders in a solid has been carried out, and the scattered field distribution at a given distance has been found to exhibit particular behaviors at different moments. Further studies on directivities and scattered fields are expected to improve the quantification of scattered images in isotropic solid materials by the phased array technique.
基金Supported by the earmarked fund for China Agriculture Research System(No.CARS-46-08)the National Science Foundation for Young Scientists of China(No.31301863)the Major Scientific and Technological Innovation Project of Hubei Province(No.2015ABA045)
文摘The mass mortality of pond-reared scattered mirror carp, Cyprinus carpio, caused by Thelohanellus kitauei, occurred at fish farms in Sichuan Province, southwest China. Morphological and molecular analyses were supplemented with histological evaluation of infected tissues to better understand the route of infection and the pathological effects of 1". kitauei on the fish host. The intestine of the diseased host was full of large cysts of the myxosporean. The cysts range from 2 cm to 3.6 cm in diameter. Histopathology indicated that T. kitauei first invaded the submucosa of the host intestine and then moved into the mucosa layers with the development of their spores, finally entering into the enteric cavity of the hosts after the disruption of mucosa layers. The pyriform spores of T. kitauei were surrounded by the transparent spore sheath, measuring 25.98/μm±0.95 μm in body length, 8.72 μm±0.51μm body width, and 7.86 μm±0.26 μm in body thickness. The single polar capsule was pyriform, measuring 14.73 μm±0.92μm in length and 6.82 μm±0.45μm in width, with eight to 10 turns of filament coils winding inside. Phylogenetic analysis based on the 18S small-subunit ribosomal DNA sequences indicated that minimal genetic differences were present between T. kitauei samples from South Korea and from China. Close affinity was found between the genus Thelohanellus and Myxobolus. Additionally, two polar capsule nuclei were found at the anterior end of the single polar capsule in spores of T. kitauei stained with hematoxylin and eosin, which suggested the separation of the genus Thelohanellus from Myxobolus.
基金Supported by the National Natural Science Foundation of China under Grant No.10045001.
文摘A new detection system in scanning electron microscope,which filters in energy and detects the backscattered electrons close to the microscope axis,is described.This technique ameliorates the dependence of the back.scat tering coefficient on atomic number,and suppresses effectively the relief contrast at the same time.Therefore this new method is very suitable to the composition analysis.
基金the Western China Program for Personnel Training of Chinese Academy of Sciences (L10416004)National Social Science Foundation of China (06BJY076)Knowledge Innovation Project Chinese Academy of Sciences
文摘Making rural settlements of Mountainous Regions in Western Sichuan as the study objects and using symbolic statistical methods, then combining the case study of Daofu County, the paper analyzes the negative impact of the scattered rural settlements on infrastructure construction, farmers' income increase and mountain ecological reconstruction in mountainous regions of western Sichuan. The results indicate that economic density is positively related to both rural settlements density (R^2=0.73) and rural population density (R^2=0.77), and it is the same for relationship between towns density and rural settlements density (R^2=0.88) and between towns density and economic density (R^2=0.71), and the scattered distribution pattern of the rural settlements and shortage of economic centers is a major factor to the lagged socioeconomic development. On the eco-economic zoning to Daofu County, the paper indicates the spatial distribution model and the industrial development model of the rural settlements need to be changed, and rural population should be concentrated in larger rural settlements with development of off-farm industries while infrastructure construction is to reinforced.
文摘For Hermite-Birkhoff interpolation of scattered multidumensional data by radial basis function (?),existence and characterization theorems and a variational principle are proved. Examples include (?)(r)=r^b,Duchon's thin-plate splines,Hardy's multiquadrics,and inverse multiquadrics.
基金co-funded by the National Natural Science Foundation of China(41904109,41974146,42074134)State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development Projects(No.20-YYGZ-KF-GC-11)+2 种基金National Key Laboratory of Electromagnetic Environment Projects(No.6142403200307)Petro China Innovation Foundation(No.2020D5007-0304)the Fundamental Research Funds for the Central Universities(No.21CX06005A)。
文摘This paper presents a new deep-reading logging-while-drilling electromagnetic(EM)logging method to detect bed boundaries ahead of bit.Unlike all existing EM logging approaches,the new method is based on the scattered electric field radiated by a magnetic dipole antenna.By analyzing the characteristics of electric tensor responses in layered formations,optimal look-ahead electric component is selected.The selected scattered field contributes to a large portion of the total field and is strongly sensitive to the boundary position.The measured voltage from the scattered electric component can be tens of times larger than that from the scattered magnetic fields and it attenuates slower.Thus,the detection capability improves significantly.A coaxial open-loop half-circle antenna is then proposed to measure the electric field in logging while drilling environment.A practical tool implementation equipped with two tilted close-loop antennas and two open-loop antennas is further developed for look-ahead application.Numerical results demonstrate that the detection depth of the new look-ahead tool can be up to 40 m under favorable conditions.Compared with current look-ahead logging tools,the new method not only significantly shortens the tool size,but also can recognize the boundary position and azimuth.
文摘Scattered storage means an item can be stored in multiple inventory bins. The scattered storage assignment problem based on association rules in Kiva mobile fulfillment system is investigated, which aims to decide the pods for each item to put on so as to minimize the number of pods to be moved when picking a batch of orders. This problem is formulated into an integer programming model. A genetic algorithm is developed to solve the large-sized problems. Computational experiments and comparison between the scattered storage strategy and random storage strategy are conducted to evaluate the performance of the model and algorithm.
文摘We use Radial Basis Functions (RBFs) to reconstruct smooth surfaces from 3D scattered data. An object's surface is defined implicitly as the zero set of an RBF fitted to the given surface data. We propose improvements on the methods of surface reconstruction with radial basis functions. A sparse approximation set of scattered data is constructed by reducing the number of interpolating points on the surface. We present an adaptive method for finding the off-surface normal points. The order of the equation decreases greatly as the number of the off-surface constraints reduces gradually. Experimental results are provided to illustrate that the proposed method is robust and may draw beautiful graphics.
文摘From July 31 to August I in 2008, a strong thunderstorm process occurred in Neijiang of Sichuan Province, and a strange scattered light- ning strike phenomenon happened in office building of Dongxing Meteorological Bureau in Neijiang. Through a series of investigations and analyses, we found occurrence reason of the scattered lightning strike and improved lightning protection measures.
基金Supported by Science Foundation of Zhejiang (No. 599008) ZUCC Science Research Foundation
文摘An improved self-organizing feature map (SOFM) neural network is presented to generate rectangular and hexagonal lattic with normal vector attached to each vertex. After the neural network was trained, the whole scattered data were divided into sub-regions where classified core were represented by the weight vectors of neurons at the output layer of neural network. The weight vectors of the neurons were used to approximate the dense 3-D scattered points, so the dense scattered points could be reduced to a reasonable scale, while the topological feature of the whole scattered points were remained.
基金Supported by National Natural Science Youth Foundation (10401021).
文摘Solving large radial basis function (RBF) interpolation problem with non-customized methods is computationally expensive and the matrices that occur are typically badly conditioned. In order to avoid these difficulties, we present a fitting based on radial basis functions satisfying side conditions by least squares, although compared with interpolation the method loses some accuracy, it reduces the computational cost largely. Since the fitting accuracy and the non-singularity of coefficient matrix in normal equation are relevant to the uniformity of chosen centers of the fitted RBE we present a choice method of uniform centers. Numerical results confirm the fitting efficiency.
基金National Key Research and Development Program of China(Nos.2016YY0200805 and 2017YFF0206205)Major Program of National Natural Science Foundation of China(No.11790324)National Magnetic Confinement Fusion Science Program of China(Nos.2013GB106004 and 2012GB101003).
文摘The time-of-flight enhanced diagnostics(TOFED)neutron spectrometer has been installed in TOFED house,which is a newly-built neutron diagnostic lab outside the EAST experimental hall.The line of sight(LOS)of TOFED is defined by the collimator going through the 150 cm biological shielding wall,which can reduce background neutrons very effectively for the neutron spectral measurements.The Monte Carlo code MCNP5 is used in the simulations to characterize collimation effects and the radiation safety of the new house.The collimator makes neutron flux almost fully perpendicular to S 1 detectors.In addition,the proportion of scattered neutrons in the LOS of the TOFED is obtained for the measured spectral data interpretation.The simulation results show that the TOFED house satisfies the requirement for the TOFED operations at EAST and gives a safe environment for personnel access during the EAST operation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61271110,60801047,and 61073106)the New Scientific and TechnologicalStar Project of Shaanxi Province,China(Grant No.2011KJXX39)+1 种基金the Aviation Science Foundation(Grant No.2011ZC53042)the Natural ScienceFoundation of Shaanxi Province,China(Grant Nos.12Jk0955 and 2014JQ0816)
文摘Based on laser radar equations, a Doppler shift model of a laser pulse beam scattered by a rotating arbitrary convex target is reported in this paper. The boundary relations between an incident pulse beam and the detected area elements are analyzed by geometric methods. The Doppler shift characteristics of the rotating cone and cylinder are discussed and the difference between the laser pulse beam and the plane wave scattered from the same rotating target is compared accordingly. Numerical simulations show that the Doppler shift is tightly relevant to their dimensions, speeds, and so on. In the same incidence conditions, the pulse beam and plane wave have difference peak values and the same Doppler shift bandwidth. If the waist radius of the pulse beam is larger, the peak value is higher, and the Doppler shifts are proportional to the speed of the rotating target. By virtue of our theoretical model, we probe into the scattered characteristics of the Doppler shifts of a laser pulse beam, which would benefit target identification in national defense.
基金Supported by the National Natural Science Foundation of China,under Grant No.9189012-06.
文摘Calculations on differential cross sections and spin polarization parameters of elastical electron scattering with Hg atoms are performed for electrons in the energy range from 0.5 to 150eV.Dirac equation is used to describe the motion of scattered electrons in the target field,which includes static,exchange and correlation-polarization interactions.The agreement between theory and experiment is generally good.
文摘In this paper an error in[4]is pointed out and a method for constructingsurface interpolating scattered data points is presented.The main feature of the methodin this paper is that the surface so constructed is polynomial,which makes the construction simple and the calculation easy.
基金the College Foundation Project,the College of Engineering and Technology of Chengdu University of Technology(No.C122018029)。
文摘A simpler and improved utility approximate point scattered function for thin-film converters currently used in neutron photographic devices is proposed as a correction method to produce clearer,more realistic images.The validity of the model was demonstrated through a simulation experiment.Based on the results,an error analysis was carried out,certain corrections were made to the original model,and the final model achieved a very low relative error in the simulation experiment.The model can also be optimized for quantitative neutron photographic analysis using iterative algorithms to obtain realistic neutron photographic images more quickly.At the end of the article,the model is extended to consider the case of energy spectrum hardening by introducing a temperature correction parameter.