The 111-Years-Old Cosmic Ray Puzzle Has Been Solved?

We show that recently multi-messenger astronomy has provided compelling evidence that the bulk of high energy cosmic rays (CRs) are produced by highly relativistic narrow jets of plasmoids launched in core collapse of stripped-envelope massive stars to neutron stars and stellar mass black holes. Such events produce also a visible GRB if the jet happens to point in our direction. This has been long advocated by the cannon ball (CB) model of high energy CRs and GRBs, but the evidence has been provided only recently by what were widely believed to be unrelated discoveries. They include the very recent discovery of a knee around TeV in the energy spectrum of high energy CR electrons, the peak photon energy in the “brightest of all time” GRB221009A, and the failure of IceCube to detect high energy neutrinos from GRBs, including GRB221009A. They were all predicted by the cannonball (CB) model of high energy CRs and GRBs long before they were discovered in observations, despite a negligible probability to occur by chance.

Study on the Performance of the GRANDProto300 Particle Detector Array by Simulation

The Giant Radio Array for Neutrino Detection(GRAND)is a proposed large-scale observatory designed to detect cosmic rays,gamma-rays,and neutrinos with energies exceeding 100 Pe V.The GRANDProto300 experiment is proposed as the early stage of the GRAND project,consisting of a hybrid array of radio antennas and scintillator detectors.The latter,as a mature and traditional detector,is used to cross-check the nature of the candidate events selected from radio observations.In this study,we developed a simulation software called G4GRANDProto300,based on the Geant4 software package,to optimize the spacing of the scintillator detector array and to investigate its effective area.The analysis was conducted at various zenith angles under different detector spacings,including 300,500,600,700,and 900 m.Our results indicate that,for large zenith angles used to search for cosmic-ray in the GRAND project,the optimized effective area is with a detector spacing of 500 m.The G4GRANDProto300 software that we developed could be used to further optimize the layout of the particle detector array in future work.

Comparison of efficacy of lung ultrasound and chest X-ray in diagnosing pulmonary edema and pleural effusion in ICU patients: A single centre, prospective, observational study

Background and Aims While chest X-ray (CXR) has been a conventional tool in intensive care units (ICUs) to identify lung pathologies, computed tomography (CT) scan remains the gold standard. Use of lung ultrasound (LUS) in resource-rich ICUs is still under investigation. The present study compares the utility of LUS to that of CXR in identifying pulmonary edema and pleural effusion in ICU patients. In addition, consolidation and pneumothorax were analyzed as secondary outcome measures. Material and Methods This is a prospective, single centric, observational study. Patients admitted in ICU were examined for lung pathologies, using LUS by a trained intensivist;and CXR done within 4 hours of each other. The final diagnosis was ascertained by an independent senior radiologist, based on the complete medical chart including clinical findings and the results of thoracic CT, if available. The results were compared and analyzed. Results Sensitivity, specificity and diagnostic accuracy of LUS was 95%, 94.4%, 94.67% for pleural effusion;and 98.33%, 97.78%, 98.00% for pulmonary edema respectively. Corresponding values with CXR were 48.33%, 76.67%, 65.33% for pleural effusion;and 36.67%, 82.22% and 64.00% for pulmonary edema respectively. Sensitivity, specificity and diagnostic accuracy of LUS was 91.30%, 96.85%, 96.00% for consolidation;and 100.00%, 79.02%, 80.00% for pneumothorax respectively. Corresponding values with CXR were 60.87%, 81.10%, 78.00% for consolidation;and 71.3%, 97.20%, 96.00% for pneumothorax respectively. Conclusion LUS has better diagnostic accuracy in diagnosis of pleural effusion and pulmonary edema when compared with CXR and is thus recommended as an effective alternative for diagnosis of these conditions in acute care settings. Our study recommends that a thoracic CT scan can be avoided in most of such cases.

The Implementation of Ray Tracing Algorithm with OpenMP Parallelization

Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the Ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture.

Transport in Astrophysics: VI. Ultra-High Energy Cosmic Rays

Two new solutions of the homogeneous diffusion equation in 1D are derived in the presence of losses and a trigonometric profile for a profile of density. A simulation for the ankle in the energy distribution of cosmic rays (CRs) is provided in the framework of the fine tuning of the involved parameters. A theoretical image for the overall diffusion of CRs in galactic coordinates is provided.

EJUSTCO:Monte Carlo radiation transport code hybrid with ANN model for gamma-ray shielding simulation

Gamma ray shielding is essential to ensure the safety of personnel and equipment in facilities and environments where radiation exists.The Monte Carlo technique is vital for analyzing the gamma-ray shielding capabilities of materials.In this study,a simple Monte Carlo code,EJUSTCO,is developed to cd simulate gamma radiation transport in shielding materials for academic purposes.The code considers the photoelectric effect,Compton(incoherent)scattering,pair production,and photon annihilation as the dominant interaction mechanisms in the gamma radiation shielding problem.Variance reduction techniques,such as the Russian roulette,survival weighting,and exponential transformation,are incorporated into the code to improve computational efficiency.Predicting the exponential transformation parameter typically requires trial and error as well as expertise.Herein,a deep learning neural network is proposed as a viable method for predicting this parameter for the first time.The model achieves an MSE of 0.00076752 and an R-value of 0.99998.The exposure buildup factors and radiation dose rates due to the passage of gamma radiation with different source energies and varying thicknesses of lead,water,iron,concrete,and aluminum in single-,double-,and triple-layer material systems are validated by comparing the results with those of MCNP,ESG,ANS-6.4.3,MCBLD,MONTEREY MARK(M),PENELOPE,and experiments.Average errors of 5.6%,2.75%,and 10%are achieved for the exposure buildup factor in single-,double-,and triple-layer materials,respectively.A significant parameter that is not considered in similar studies is the gamma ray albedo.In the EJUSTCO code,the total number and energy albedos have been computed.The results are compared with those of MCNP,FOTELP,and PENELOPE.In general,the EJUSTCO-developed code can be employed to assess the performance of radiation shielding materials because the validation results are consistent with theoretical,experimental,and literary results.

Simulation of a soft-gamma-ray polarimeter on board a microsatellite

Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technology,the advantages of space exploration have become increasingly apparent.Therefore,we simulated a soft-gamma-ray polarimeter for a microsatellite based on the Compton scattering principle.We performed detailed Monte Carlo simulations using monoenergetic gamma-ray linear-polarization sources and Crab-like sources in the energy range of 0.1-10 MeV considering the orbital background.The polarimeter exhibited excellent polarization detection performance.The modulation factor was 0.80±0.01,and the polarization angles were accurate within an error of 0.2°at 200 keV for on-axis incidence.For the Crab-like sources for on-axis incidence,the polarization degrees were consistent with the set values within the error tolerance,the modulation factor was 0.76±0.01,and the minimum detectable polarization reached 2.4%at 3σfor an observation time of10^(6) s.Additionally,the polarimeter exhibited recoil electron tracking,imaging,and powerful background suppression in a large field of view(FoV;∼2πsr).The proposed polarimeter meets the requirements of a space soft-gamma-ray polarization detector and has promising research prospects.

Injection Spectra of Different Species of Cosmic Rays from AMS-02, ACE-CRIS and Voyager-1

Precise measurements of energy spectra of different cosmic ray(CR) species have been obtained in recent years, by particularly the AMS-02 experiment on the International Space Station. It has been shown that apparent differences exist in different groups of the primary CRs. However, it is not straightforward to conclude that the source spectra of different particle groups are different since they will experience different propagation processes(e.g., energy losses and fragmentations) either. In this work, we study the injection spectra of different nuclear species using the measurements from Voyager-1 outside the solar system, and ACR-CRIS and AMS-02 on the top of atmosphere, in a physical framework of CR transportation. Two types of injection spectra are assumed, the broken power-law(BPL) form and the non-parametric spline interpolation form. The non-parametric form fits the data better than the BPL form, implying that potential structures beyond the constrained spectral shape of BPL may exist. For different nuclei the injection spectra are overall similar in shape but do show some differences among each other. For the non-parametric spectral form, the helium injection spectrum is the softest at low energies and the hardest at high energies. For both spectral shapes, the low-energy injection spectrum of neon is the hardest among all these species, and the carbon and oxygen spectra have more prominent bumps in 1–10 GV in the R2 d N dRpresentation.Such differences suggest the existence of differences in the sources or acceleration processes of various nuclei of CRs.

Point cloud-based environment reconstruction and ray tracing simulations for railway tunnel channels

Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing system performance.Ray tracing is an effective method to investigate propagation characteristics in a complex environment,and how to quickly and accurately obtain environmental information needs to be solved.This paper presents dynamic environment reconstruction and ray tracing simulation in railway tunnel environment based on Simultaneous Localization and Mapping(SLAM)algorithm and Poisson reconstruction algorithm.Accurate channel parameters are obtained and analyzed based on ray tracing simulation.Both straight and curved tunnels are considered and investigated,and the results show the channel characteristics in complex railway tunnel environments.

方ray可解方程组与rayS^＊-阵的图论特征

给出了系数矩阵为方阵的复线性方程组为ray可解、非负ray可解及全非零ray可解等的图论特征刻画,得到了这些方程组的解的ray模式的图论表述.应用这些结论还给出了ray S*-阵和ray S-阵的图论特征刻画,及其他若干类特殊的复线性方程组的ray可解性条件.

The Role of Atmospheric Pressure, Temperature, and Humidity on Cosmic Ray Muons at a Low Latitude Station

This study aimed to investigate the relationship between atmospheric conditions and cosmic ray (CR) muons using daily and monthly CR data collected by the KAAU muon detector in Jeddah, Saudi Arabia between 2007 and 2012. Specifically, the study examined the effects of atmospheric pressure, air temperature, and relative humidity on CR muons at different time scales (annual, seasonal, and monthly). The results of the analysis revealed that atmospheric pressure and air temperature had a negative impact on CR muons, while relative humidity had a positive impact. Although air temperature and relative humidity had small mean values across all time scales, their coefficients varied significantly from month to month and season to season. In addition, the study conducted multivariable correlation analyses for each day, which showed that pressure coefficients had consistently negative mean values, while the temperature and humidity coefficients had varying effects, ranging from positive to negative values. The reasons for the variations in the coefficients are not yet fully understood, but the study proposed several possible terrestrial and extraterrestrial explanations. These findings provide important insights into the complex interactions between the Earth’s atmosphere and cosmic rays, which can contribute to a better understanding of the potential impacts of cosmic rays on the Earth’s climate and environment.

基于Ray框架的分布式计算研究

文章旨在通过分布式框架Ray来计算数据量比较大的任务,使得任务能够更加高效地完成。指明了Ray通过两种核心概念实现分布式计算:Actor和Task。通过调用Ray库中的Remote方法并结合init方法指明CPU数量实现分布式计算。实验分为在相同数据量下不同CPU数量处理数据的快慢以及在不同数据量下不同CPU数量处理数据的能力。实验结果表明,数据量越大、CPU数量越多的分布式计算能力越强。因此,分布式计算适用于大数据下的并行计算。

基于整数小波变换的Ray-Period压缩算法

为解决基于传统小波变换的数据压缩方法存在的问题,在深入分析整数提升过程的基础上,提出了一种基于整数小波变换的Ray-Period压缩算法。该算法针对电力数据的特点,根据整数小波变换多分辨率分析的特性,将原始数据变换到小波域,以使变换后的信号能量主要集中在低频系数上,而后采用无损的Ray-Period压缩算法处理低频数据,采用改进的阈值压缩算法处理高频系数,并采用新的位图压缩算法处理阈值压缩后元素值超过3.125%时的非零元素。采用实际数据进行压缩,该算法的能量恢复系数优于10?4,压缩比小于6.39%,速度比传统的小波变换压缩算法提高了近1倍。

Biaggini Ray Set间接粘接系统在舌侧正畸中的应用

目的 介绍一种粘接舌侧托槽的间接粘接系统。方法 将BiagginiRaySet应用到舌侧正畸 ,介绍整个粘接系统的原理和具体操作步骤。结果 该系统托槽定位精确 ,不需要进行排牙试验。结论 将RaySet间接粘接的方法和理念应用到舌侧正畸中 ,能达到满意的托槽定位效果。

Ray Casting的医学体数据场绘制算法

为了在普通微机上实现对医学体数据场的实时清晰绘制,给出了一种多种因素融合的光学属性赋值方法,进而提出一种新的医学体绘制算法。将医学体数据场进行分类,对于前景体素集采用LOD(Layer of Detail)技术进行重采样;然后用定义的光学属性赋值方法对采样点赋值,从而将物体距离视点的距离与物体距离光源的距离有效地结合起来。最后,采用基于空间跳跃的加速技术显示背景体素。实验结果表明:对于512×512×482×2 Byte大小的体数据在减少至原来大小2/3的情况下,在普通微机上能够达到2.5 frame/s的清晰绘制。本算法能够实现一般大小体数据场的实时绘制,而且组织器官显示清晰,符合人的视觉特征。

RAY-Period压缩算法的研究与实现

针对电力系统中电能量数据传输的特点,研究并分析了数据库压缩算法RAY与周期压缩算法相结合的压缩算法。结合位图压缩方法,详细阐述了RAY和周期算法的压缩思想。最后给出了RAY-Period算法的压缩流程,并用C语言最终实现了这一算法。经过测试,能够对电能量数据进行有效压缩,有效减少了网络传输数据量,具有很大的实用价值。

Dark Matter Particle Explorer: The First Chinese Cosmic Ray and Hard γ-ray Detector in Space

The Dark Matter Particle Explorer(DAMPE) mission is one of the five scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Science(CAS) approved in 2011. The main scientific objective of DAMPE is to detect electrons and photons in the range of 5 GeV–10 TeV with unprecedented energy resolution(1.5% at 100 GeV) in order to identify possible Dark Matter(DM) signatures. It will also measure the flux of nuclei up to above 500 TeV with excellent energy resolution(40% at 800 GeV), which will bring new insights to the origin and propagation high energy cosmic rays. With its excellent photon detection capability, the DAMPE mission is well placed for new discoveries in high energy-ray astronomy as well.

Refraction of extraordinary rays and ordinary rays in the Savart polariscope

The refraction of rays in the Savart polariscope is different from the isotropic medium. We have analysed and discussed the refraction of rays in the Savart polariscope on the basis of the Snell law. The refraction formulae of the extraordinary rays and ordinary rays were derived. Results obtained may provide theoretical and practical guide lines for studying, developing and engineering of polarization interference imaging spectrometer.

基于Marching Cubes与Ray Casting的医学图像三维重建

本文研究了医学图像三维面绘制和体绘制的典型算法MarchingCube和RayCasting的原理和三维可视化工具包VTK的实现机制,在VC++6.0平台下,利用VTK分别实现了基于上述算法的DICOM格式的CT序列图像三维重建,并给出了关键算法和3D可视化结果。

基于3dmax和V-Ray的视觉传达设计的实现

视觉传达设计中的平面广告设计制作一般都是由Coreldraw、Photoshop等平面设计软件制作而成,这里笔者提供了用三维设计制作软件3dmax、V-Ray结合二维平面设计软件Coreldraw、Photoshop来进行平面广告视觉传达设计的方法。