期刊文献+
共找到1,631篇文章
< 1 2 82 >
每页显示 20 50 100
Automatic modulation recognition of radiation source signals based on two-dimensional data matrix and improved residual neural network
1
作者 Guanghua Yi Xinhong Hao +3 位作者 Xiaopeng Yan Jian Dai Yangtian Liu Yanwen Han 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期364-373,共10页
Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive radio.However,the AMR of radiation source signals at low SNRs still faces a great challenge.Therefore,the ... Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive radio.However,the AMR of radiation source signals at low SNRs still faces a great challenge.Therefore,the AMR method of radiation source signals based on two-dimensional data matrix and improved residual neural network is proposed in this paper.First,the time series of the radiation source signals are reconstructed into two-dimensional data matrix,which greatly simplifies the signal preprocessing process.Second,the depthwise convolution and large-size convolutional kernels based residual neural network(DLRNet)is proposed to improve the feature extraction capability of the AMR model.Finally,the model performs feature extraction and classification on the two-dimensional data matrix to obtain the recognition vector that represents the signal modulation type.Theoretical analysis and simulation results show that the AMR method based on two-dimensional data matrix and improved residual network can significantly improve the accuracy of the AMR method.The recognition accuracy of the proposed method maintains a high level greater than 90% even at -14 dB SNR. 展开更多
关键词 Automatic modulation recognition radiation source signals Two-dimensional data matrix Residual neural network Depthwise convolution
下载PDF
New Individual Identification Method of Radiation Source Signal Based on Entropy Feature and SVM 被引量:5
2
作者 Yun Lin Xiao-Chun Xu Zi-Cheng Wang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第1期98-101,共4页
In this paper,according to the defect of methods which have low identification rate in low SNR,a new individual identification method of radiation source based on information entropy feature and SVM is presented. Firs... In this paper,according to the defect of methods which have low identification rate in low SNR,a new individual identification method of radiation source based on information entropy feature and SVM is presented. Firstly,based on the theory of multi-resolution wavelet analysis,the wavelet power spectrum of noncooperative signal can be gotten. Secondly,according to the information entropy theory,the wavelet power spectrum entropy is defined in this paper. Therefore,the database of signal's wavelet power spectrum entropy can be built in different SNR and signal parameters. Finally,the sorting and identification model based on SVM is built for the individual identification of radiation source signal. The simulation result indicates that this method has a high individual's identification rate in low SNR,when the SNR is greater than 4 dB,the identification rate can reach 100%. Under unstable SNR conditions,when the range of SNR is between 0 dB and 24 dB,the average identification rate is more than 92. 67%. Therefore,this method has a great application value in the complex electromagnetic environment. 展开更多
关键词 radiation source INDIVIDUAL identification WAVELET power spectrum information ENTROPY support VECTOR machine
下载PDF
Correlation between Low Tube Voltage in Dual Source CT Coronary Artery Imaging with Image Quality and Radiation Dose 被引量:6
3
作者 雷子乔 韩萍 +2 位作者 徐海波 余建明 刘红利 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2014年第4期616-620,共5页
The influence of low tube voltage in dual source CT(DSCT) coronary artery imaging on image quality and radiation dose and its application value in clinical practice were investigated. Totally, 300 cases of chest pai... The influence of low tube voltage in dual source CT(DSCT) coronary artery imaging on image quality and radiation dose and its application value in clinical practice were investigated. Totally, 300 cases of chest pain with low body mass index(BMI 〈18.5 kg/m2) subjected to DSCT coronary artery imaging were prospectively enrolled. The heart rate in all patients were greater than 65/min. The retrospective ECG gated scanning mode and simple random sampling method were used to assign the patients into groups A, B and C(n=100 each). The patients in groups A, B and C experienced 120-, 100-, and 80-kV tube voltage imaging respectively, and the image quality was evaluated. The CT volume dose index(CTDIvol) and dose length product(DLP) were recorded, and the effective dose(ED) was calculated in each group. The image quality scores and radiation doses in groups were compared, and the influence of tube voltage on image quality and radiation dose was analyzed. The results showed that the excellent rate of image quality in groups A, B and C was 95.69%, 94.72% and 96.33% respectively with the difference being not statistically significant among the three groups(P〉0.05). The CTDIvol values in groups A, B and C were 51.35±12.21, 21.28±7.13 and 6.34±3.34 mGy, respectively, with the difference being statistically significant(P〈0.05). The ED values in groups A, B and C were 9.27±1.63, 4.56±2.29 and 2.29±1.69 mSv, respectively, with the difference being statistically significant(P〈0.05). It was suggested that for the patients with low BMI, the application of DSCT coronary artery imaging with low tube voltage can obtain satisfactory image quality, and simultaneously, significantly reduce the radiation dose. 展开更多
关键词 dual source CT coronary angiography TOMOGRAPHY radiation dose low body mass index
下载PDF
A Method of Identifying Electromagnetic Radiation Sources by Using Support Vector Machines 被引量:2
4
作者 石丹 高攸纲 《China Communications》 SCIE CSCD 2013年第7期36-43,共8页
Electromagnetic Radiation Source Identification(ERSI) is a key technology that is widely used in military and radiation management and in electromagnetic interference diagnostics.The discriminative capability of machi... Electromagnetic Radiation Source Identification(ERSI) is a key technology that is widely used in military and radiation management and in electromagnetic interference diagnostics.The discriminative capability of machine learning methods has recently been used for facilitating ERSI.This paper presents a new approach to improve ERSI by adopting support vector machines,which are proven to be effective tools in pattern classification and regression,on the basis of the spatial distribution of electromagnetic radiation sources.Spatial information is converted from 3D cubes to 1D vectors with subscripts as inputs in order to simplify the model.The model is trained with 187 500 data sets in order to enable it to identify the types of radiation source types with an accuracy of up to 99.9%.The influence of parameters(e.g.,penalty parameter,reflection and noise from the ambient environment,and the scaling method for the input data) are discussed.The proposed method has good performance in noisy and reverberant environment.It has an identification accuracy of 82.15% when the signal-to-noise ratio is 20 dB.The proposed method has better accuracy in a noisy environment than artificial neural networks.Given that each Electromagnetic(EM) source has unique spatial characteristics,this method can be used for EM source identification and EM interference diagnostics. 展开更多
关键词 support vector machines electro- magnetic radiation sources spatial characteistics IDENTIFICATION
下载PDF
Experimental Study of the X-Ray Radiation Source at Approximately Constant Radiation Temperature 被引量:1
5
作者 宋天明 杨家敏 +2 位作者 杨冬 李志超 尚万里 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第11期1108-1111,共4页
An X-ray radiation source with approximately constant radiation temperature is realized by irradiating golden hohlraum with a shaped laser pulse. A simple theoretical model based on power balance is used to design the... An X-ray radiation source with approximately constant radiation temperature is realized by irradiating golden hohlraum with a shaped laser pulse. A simple theoretical model based on power balance is used to design the shape of the drive laser pulse. Experiments are carried out on the Shenguang III prototype laser facility, and the experimentM results are presented for radiation sources with the flat-top lasting about 2.5 ns at two different peak temperatures of about 150 eV and 170 eV, respectively, including the the drive laser pulses and the time integrated possible improvements are discussed. time histories of the temperatures, the shapes of radiation spectra. The validity of the model and 展开更多
关键词 X-ray radiation source laser pulse shaping power balance
下载PDF
Application of Transient Electromagnetic Method with Multi-Radiation Field Sources in Deep Edge Mineral Resources Exploration 被引量:2
6
作者 ZENG Youqiang ZENG Gaofu +3 位作者 HUANG Lishan LI Xiu GUO Jianlei WANG Jianchao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2021年第S01期99-101,共3页
In recent years,in order to meet the practical needs of deep edge mine detection with large depth and high precision,transient electromagnetic method(TEM)near emission source detection mode has become an international... In recent years,in order to meet the practical needs of deep edge mine detection with large depth and high precision,transient electromagnetic method(TEM)near emission source detection mode has become an international advanced method(Xue et al.,2020). 展开更多
关键词 multiple radiation field sources exploration of deep mineral resources transient electromagnetic method
下载PDF
Compact Z-pinch radiation source dedicated to broadband absorption measurements 被引量:1
7
作者 Dunpin Hong Herve Rabat +2 位作者 Erwan Le Menn Clement Zaepffel Jean-Marc Bauchire 《Matter and Radiation at Extremes》 SCIE EI CAS 2016年第3期179-186,共8页
In order to acquire a broadband absorption spectrum in a single shot,a compact radiation source was developed by using a Z-pinch type electric discharge.This paper presents the mechanical and electrical construction o... In order to acquire a broadband absorption spectrum in a single shot,a compact radiation source was developed by using a Z-pinch type electric discharge.This paper presents the mechanical and electrical construction of the source,as well as its electrical and optical characteristics,including the intense continuum of radiation emitted by the source in the UV and visible spectral range.It also shows that the compactness of the source allows direct coupling with the probed medium,enabling broadband absorption measurement in the spectral range of 200e300 nm without use of an optical fiber which strongly attenuates the light in the short wavelength range.Concretely,thanks to this source,broadband spectral absorption of NO molecules around 210 nm and that of OH molecules around 310 nm were recorded in this direct coupling arrangement.Copper atom spectral absorption around 325 nm of the peripheral cold zones of an intense transient arc was also recorded. 展开更多
关键词 Z-PINCH Broadband radiation source Broadband absorption spectrum
下载PDF
Thermal Radiation, Heat Source/Sink and Work Done by Deformation Impacts on MHD Viscoelastic Fluid over a Nonlinear Stretching Sheet 被引量:1
8
作者 F. M. Hady R. A. Mohamed Hillal M. ElShehabey 《World Journal of Mechanics》 2013年第4期203-214,共12页
This work is focused on the effects of heat source/sink, viscous dissipation, radiation and work done by deformation on flow and heat transfer of a viscoelastic fluid over a nonlinear stretching sheet. The similarity ... This work is focused on the effects of heat source/sink, viscous dissipation, radiation and work done by deformation on flow and heat transfer of a viscoelastic fluid over a nonlinear stretching sheet. The similarity transformations have been used to convert the governing partial differential equations into a set of nonlinear ordinary differential equations. These equations are then solved numerically using a very efficient implicit finite difference method. Favorable comparison with previously published work is performed and it is found to be in excellent agreement. The results of this parametric study are shown in several plots and tables and the physical aspects of the problem are highlighted and discussed. 展开更多
关键词 Flow and HEAT Transfer Second Grade Fluid NONLINEAR Stretching Sheet HEAT source radiation
下载PDF
Effects of Radiations and Heat Source/Sink on a Casson Fluid Flow over Nonlinear Stretching Sheet 被引量:1
9
作者 Chenna Sumalatha Shankar Bandari 《World Journal of Mechanics》 2015年第12期257-265,共9页
The present study deals with the flow over a nonlinearly stretching sheet of Casson fluid with the effects of radiation and heat source/sink. The Casson fluid model is used to characterize the non-Newtonian fluid beha... The present study deals with the flow over a nonlinearly stretching sheet of Casson fluid with the effects of radiation and heat source/sink. The Casson fluid model is used to characterize the non-Newtonian fluid behaviour. With the help of justified similarity transformations the governing equations were reduced to couple nonlinear ordinary differential equations. The effective numerical technique Keller Box method is used to solve these equations. The variations in velocity, temperature profiles were presented with the various values of nonlinear stretching parameter n and Casson parameter β. The nature of Skinfriction and Local nusselt number has presented. Effects of radiation and heat source/sink on temperature profiles have been discussed. 展开更多
关键词 NONLINEAR STRETCHING Sheet Casson Fluid Keller BOX Method radiation Heat source/Sink
下载PDF
Radiation-induced attenuation self-compensating effect in super-fluorescent fiber source 被引量:2
10
作者 杨远洪 索鑫鑫 杨巍 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第9期266-270,共5页
The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced at... The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation (RIA) self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation (RIBA) at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward (DPB) configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad (Si) gamma-ray irradiation. 展开更多
关键词 super-fluorescent fiber source Er-doped fiber radiation-induced attenuation mean wavelength stability
下载PDF
Research on Energy Radiation Characteristics of an Airgun Source Excited in Land Reservoir
11
作者 DONG Mingrong FU Liyun +3 位作者 XING Chao YANG Shaodong YANG Jun LI Xiaobin 《Earthquake Research in China》 CSCD 2019年第1期24-36,共13页
The energy radiation process of an airgun seismic source in land reservoir is studied based on the underwater wavelet data collected in the airgun excitation experiments in Binchuan, Yunnan, China. The empirical formu... The energy radiation process of an airgun seismic source in land reservoir is studied based on the underwater wavelet data collected in the airgun excitation experiments in Binchuan, Yunnan, China. The empirical formula for calculating the bubble pulsation period and the maximum radius of the underwater airgun seismic source is obtained. The results show that: ① The energy radiation efficiency is higher vertically than horizontally. ② The vertical bubble energy radiation efficiency increases with the increase of the air supply pressure. ③ The vertical energy radiation efficiency of the airgun seismic source is 9.4% when the air supply pressure is 15 MPa. ④ The higher the air supply pressure, the further the propagating distance of the superposition-enhanced pressure wave of an airgun source. 展开更多
关键词 LAND RESERVOIR Airgun seismic source Shock wave BUBBLE ENERGY radiation Process
下载PDF
Effects of homogeneous-heterogeneous reactions and thermal radiation on magneto-hydrodynamic Cu-water nanofluid flow over an expanding flat plate with non-uniform heat source
12
作者 DOGONCHI A S CHAMKHA Ali J +3 位作者 HASHEMI-TILEHNOEE M SEYYEDI S M RIZWAN-UL-HAQ GANJI D D 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第5期1161-1171,共11页
This study presents the effect of non-uniform heat source on the magneto-hydrodynamic flow of nanofluid across an expanding plate with consideration of the homogeneous-heterogeneous reactions and thermal radiation eff... This study presents the effect of non-uniform heat source on the magneto-hydrodynamic flow of nanofluid across an expanding plate with consideration of the homogeneous-heterogeneous reactions and thermal radiation effects.A nanofluid’s dynamic viscosity and effective thermal conductivity are specified with Corcione correlation.According to this correlation,the thermal conductivity is carried out by the Brownian motion.Similarity transformations reduce the governing equations concerned with energy,momentum,and concentration of nanofluid and then numerically solved.The influences of the effective parameters,e.g.,the internal heat source parameters,the volume fraction of nanofluid,the radiation parameter,the homogeneous reaction parameter,the magnetic parameter,the heterogeneous parameter and the Schmidt number are studied on the heat and flow transfer features.Further,regarding the effective parameters of the present work,the correlation for the Nusselt number has been developed.The outcomes illustrate that with the raising of the heterogeneous parameter and the homogeneous reaction parameter,the concentration profile diminishes.In addition,the outcomes point to a reverse relationship between the Nusselt number and the internal heat source parameters. 展开更多
关键词 NANOFLUID non-uniform heat source homogeneous-heterogeneous reactions thermal radiation Brownian motion
下载PDF
A novel approach for unlabeled samples in radiation source identification
13
作者 YANG Haifen ZHANG Hao +1 位作者 WANG Houjun GUO Zhengyang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第2期354-359,共6页
Radiation source identification plays an important role in non-cooperative communication scene and numerous methods have been proposed in this field. Deep learning has gained popularity in a variety of computer vision... Radiation source identification plays an important role in non-cooperative communication scene and numerous methods have been proposed in this field. Deep learning has gained popularity in a variety of computer vision tasks. Recently, it has also been successfully applied for radiation source identification.However, training deep neural networks for classification requires a large number of labeled samples, and in non-cooperative applications, it is unrealistic. This paper proposes a method for the unlabeled samples of unknown radiation source. It uses semi-supervised learning to detect unlabeled samples and label new samples automatically. It avoids retraining the neural network with parameter-transfer learning. The results show that compared with the traditional algorithms, the proposed algorithm can offer better accuracy. 展开更多
关键词 radiation source identification deep learning semisupervised learning
下载PDF
Thermal Radiation of Hydromagnetic Stagnation Gravity-Driven Flow through a Porous Confined Cylinder with Non-Uniform Heat Source
14
作者 O. K. Onanuga M. A. C. Chendo N. E. Erusiafe 《Open Journal of Fluid Dynamics》 2018年第4期361-377,共17页
The focus of the study is to examine thermal radiation and viscous dissipative heat transfers of magnetohydrodynamics (MHD) stagnation point flow past a permeable confined stretching cylinder with non-uniform heat sou... The focus of the study is to examine thermal radiation and viscous dissipative heat transfers of magnetohydrodynamics (MHD) stagnation point flow past a permeable confined stretching cylinder with non-uniform heat source or sink. The formulated equation governing the flow is non-dimensional. The dimensionless momentum and energy equation are solved using shooting technique coupled with fourth-order Runge-kutta integrated scheme which satisfied smoothness conditions at the edge of the boundary layer. The result for the velocity and temperature distributions are presented graphically and discussed to portray the effects of some important embodiment parameters on the flow. The Nusselt number and skin friction were obtained and compared with the previous scholars’ results in others to validate the present research work. 展开更多
关键词 Dissipation STAGNATION FLOW MAGNETOHYDRODYNAMIC FLOW Thermal radiation Heat source/Sink
下载PDF
Dose Assessment for Some Industrial Gamma Sources with an Application to a Radiation Accident
15
作者 Eman Massoud 《Open Journal of Modelling and Simulation》 2014年第1期4-11,共8页
Accidents involving industrial radiography are the most frequent cause of severe or fatal overexposure to workers and the public. On May 5, 2000, a radiation accident happened at a construction site in a gamma radiogr... Accidents involving industrial radiography are the most frequent cause of severe or fatal overexposure to workers and the public. On May 5, 2000, a radiation accident happened at a construction site in a gamma radiography practice at the village of Meet Halfa-Egypt. The accident was a severe overdose of non-radiation workers due to external exposure of Ir-192. This paper provides a methodology for calculating doses and dose rates from the most commonly used industrial γ-sources: 192Ir, 60Co, 134Cs, 137Cs and 131I. For this purpose, MCNP computer code based on Monte Carlo technique is used. The applied method helps firstly in studying and analyzing the doses from the above mentioned sources. Secondly, it provides a lead container design in a trial to reduce the dose rate within the permissible. Computer models were used to simulate the 192Ir Meet Halfa accident. To verify these models, the calculated doses were compared with a well-known empirical formula to convert source activity into dose rate and then the models were applied at different distances to analyze the factors that affect the deposited dose in the human body to find out the dose received by the victims. 展开更多
关键词 radiation Accidents sourceS Used in INDUSTRY DOSE Assessment
下载PDF
Continued Study on Hohlraum Radiation Source with Approximately Constant Radiation Temperature
16
作者 宋天明 杨家敏 +2 位作者 朱托 李志超 黄成武 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第4期342-345,共4页
An experiment was performed on the Shenguang III prototype laser facility to continue the study on hohlraum radiation source with approximately constant radiation temperature using a continuously shaped laser pulse.A ... An experiment was performed on the Shenguang III prototype laser facility to continue the study on hohlraum radiation source with approximately constant radiation temperature using a continuously shaped laser pulse.A radiation source with a flattop temperature of about130 e V that lasted about 5 ns was obtained.The previous analytical iteration method based on power balance and self-similar solution of ablation was modified taking into account the plasma movements and it was used to design the laser pulse shape for experiment.A comparison between experimental results and simulation is presented and better agreement was achieved using the modified method.Further improvements are discussed. 展开更多
关键词 X-ray radiation source laser pulse shaping power balance
下载PDF
Sources of IR Radiation in the Earth’s Atmosphere in Connection with the PeTa Effect
17
作者 Vitali A. Tatartchenko 《Optics and Photonics Journal》 2021年第6期152-196,共45页
The PeTa (Perelman-Tatartchenko) effect is the radiation of the energy of a first-order phase transition during the transition from a less condensed phase to a more condensed one. The effect was independently discover... The PeTa (Perelman-Tatartchenko) effect is the radiation of the energy of a first-order phase transition during the transition from a less condensed phase to a more condensed one. The effect was independently discovered by M. Perelman and the author of this paper. Six papers on the PeTa effect have been published in this journal over the past nine years. They are devoted to the development of PeTa models to explain the following phenomena: IR radiation from cold surfaces, cavitation luminescence/sonoluminescence (CL/SL), laser-induced bubble luminescence (LIBL), and vapor bubble luminescence (VBL) in underwater geysers. This paper describes the sources of PeTa radiation in the Earth’s atmosphere. These sources of infrared radiation have been investigated by numerous research groups, but their interpretation either does not exist at all, or it is erroneous. The following phenomena are specifically considered: PeTa radiation during the formation of clouds and fog;a pulse laser based on the PeTa radiation;condensation explosions as sources of PaTa radiation;measurement of the concentration of water vapor in the atmosphere using PeTa radiation;atmospheric scintillation of infrared radiation in the atmosphere due to the PeTa effect;PeTa radiation as a source of comfort for the igloo;the influence of PeTa radiation on living organisms;PeTa radiation due to characteristics of tropical storms;PeTa radiation as a possible precursor to earthquakes. The problem of global warming, which worries everyone, as it turns out, is also associated with the PeTa effect. 展开更多
关键词 PeTa (Perelman-Tatartchenko) Effect sources of PeTa radiation in the Earth’s Atmosphere Pulse IR Laser Condensation Explosions Atmospheric IR Scintillations Tropical Storms EARTHQUAKES Global Warming
下载PDF
Radiation dose analysis of computed tomography coronary angiography in Children with Kawasaki disease
18
作者 Mahesh Chandra Bhatt Manphool Singhal +4 位作者 Rakesh Kumar Pilania Subhash Chand Bansal Niranjan Khandelwal Pankaj Gupta Surjit Singh 《World Journal of Clinical Pediatrics》 2023年第4期230-236,共7页
BACKGROUND There is evolving role of computed tomography coronary angiography(CTCA)in non-invasive evaluation of coronary artery abnormalities in children with Kawasaki disease(KD).Despite this,there is lack of data o... BACKGROUND There is evolving role of computed tomography coronary angiography(CTCA)in non-invasive evaluation of coronary artery abnormalities in children with Kawasaki disease(KD).Despite this,there is lack of data on radiation dose in this group of children undergoing CTCA.AIM To audit the radiation dose of CTCA in children with KD.METHODS Study(December 2013-February 2018)was performed on dual source CT scanner using adaptive prospective electrocardiography-triggering.The dose length product(DLP in milligray-centimeters-mGy.cm)was recorded.Effective radiation dose(millisieverts-mSv)was calculated by applying appropriate age adjusted conversion factors as per recommendations of International Commission on Radiological Protection.Radiation dose was compared across the groups(0-1,1-5,5-10,and>10 years).RESULTS Eighty-five children(71 boys,14 girls)with KD underwent CTCA.The median age was 5 years(range,2 mo-11 years).Median DLP and effective dose was 21 mGy.cm,interquartile ranges(IQR)=15(13,28)and 0.83 mSv,IQR=0.33(0.68,1.01)respectively.Mean DLP increased significantly across the age groups.Mean effective dose in infants(0.63 mSv)was significantly lower than the other age groups(1-5 years 0.85 mSv,5-10 years 1.04 mSv,and>10 years 1.38 mSv)(P<0.05).There was no significant difference in the effective dose between the other groups of children.All the CTCA studies were of diagnostic quality.No child required a repeat examination.CONCLUSION CTCA is feasible with submillisievert radiation dose in most children with KD.Thus,CTCA has the potential to be an important adjunctive imaging modality in children with KD. 展开更多
关键词 Computed tomography coronary angiography Coronary artery abnormalities Dual source computed tomography Kawasaki disease radiation exposure
下载PDF
Distributional Relations on Impulse Radiating Surface and Point Type Sources
19
作者 Burak Polat 《Journal of Mathematics and System Science》 2012年第2期72-81,共10页
The electromagnetic field relations are demonstrated on impulse radiating surface and point type sources, which are characterized by first and second order singularities at rest in a Schwartz-Sobolev space setting. Th... The electromagnetic field relations are demonstrated on impulse radiating surface and point type sources, which are characterized by first and second order singularities at rest in a Schwartz-Sobolev space setting. The investigation starts with a general introduction to Schwartz-Sobolev distributions, the electromagnetic field equations and various modes of impulsive radiation. This is followed by an outline of temporal distributional relations in arbitrary media and distributional derivative operations on an arbitrary regular surface, all of which are employed in an investigation of impulse radiation mechanism on single and double layer sources. Similar steps are followed in a description of point distributions and investigation of impulse radiation mechanism on electric and magnetic point dipoles. 展开更多
关键词 Generalized functions electromagnetic phenomena single and double layers point sources impulse radiation.
下载PDF
Coupling model for unsteady MHD flow of generalized Maxwell fluid with radiation thermal transform* 被引量:1
20
作者 Yaqing LIU Boling GUO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2016年第2期137-150,共14页
This paper introduces a new model for the Fourier law of heat conduction with the time-fractional order to the generalized Maxwell fluid. The flow is influenced by magnetic field, radiation heat, and heat source. A fr... This paper introduces a new model for the Fourier law of heat conduction with the time-fractional order to the generalized Maxwell fluid. The flow is influenced by magnetic field, radiation heat, and heat source. A fractional calculus approach is used to establish the constitutive relationship coupling model of a viscoelastic fluid. We use the Laplace transform and solve ordinary differential equations with a matrix form to obtain the velocity and temperature in the Laplace domain. To obtain solutions from the Laplace space back to the original space, the numerical inversion of the Laplace transform is used. According to the results and graphs, a new theory can be constructed. Comparisons of the associated parameters and the corresponding flow and heat transfer characteristics are presented and analyzed in detail. 展开更多
关键词 Maxwell fluid fractional derivative radiation heat heat source Laplacetransform
下载PDF
上一页 1 2 82 下一页 到第
使用帮助 返回顶部