China Joins Hunt for Cosmic Rays

正On the beautiful Haizi Mountain 4,410 m above sea level in southwest China's Sichuan Province,construction work has begun on one of the world’s biggest and most sensitive cosmic ray detection facilities.Upon completion in 2020,the 1.2 billion yuan(180 million dollar)Large High Altitude Air Shower Observatory(LHAASO)will not only search for the sources of different types of high     

On the Supernova-remnant Origin of Galactic Cosmic Rays

<正>In the early 20~(th) century,thanks to improved precision of ionization measurement,atmospheric ionization was widely observed and attributed to high-energy radiations generated by the decay of radioactive elements on the Earth.From 1911 to 1913,by carrying out a series of high-altitude balloon experiments,Austrian physicist Victor Franz Hess discovered high-energy radiations     

宇宙线研究在中国——纪念宇宙线发现100周年

今年是宇宙线发现100周年。本文回顾了宇宙线研究在中国的传入和发展历程,重点考察了我国早期留学物理学者的前沿工作、云南高山站的建立、宇宙线研究所的拟议和停办、高山乳胶室的发展,并简要论述了20世纪80年代以来的超高能现象研究和天体物理研究。宇宙线研究在中国的曲折历程是我国基础科学发展的缩影,科学知识扩展的需要是科学仪器和科学机构发展变化的内在动力。     

Cosmic rays and particle physics at extremely high energies

Cosmic ray extensive air shower observations can give clues about the properties of high-energy particle interactions above 10¹⁵eV, in addition to giving information about the primary cosmic ray spectrum at these energies. A brief review of recent high energy accelerator data and its theoretical interpretation is given to explain the necessity for obtaining information from cosmic rays about hadronic interactions beyond machine energies. In particular, it is shown that recent measurements of the energy dependence of total cross-sections and of production cross-sections suggest some sort of threshold behavior in the 1000 GeV region. Studies at higher energies are required to understand the nature of this behavior. The use of air shower data for this purpose is illustrated by comparing shower size us depth measurements with the expectations of various models of strong interactions.     

2001年11月24日特大磁暴前银河宇宙线短时间尺度功率谱分析

采用北京宇宙线超中子堆 5min的数据,利用快速傅里叶变换计算宇宙线的功率谱方法,分析了 2 0 0 1年 1 1月 2 4日特大磁暴前银河宇宙线短时间尺度(t<1h)的功率谱。计算结果表明,在 2 0 0 1年 1 1月 1 8日到 2 0日之间,银河宇宙线的功率谱没有特别突出的特征。在 2 0 0 1年 1 1月 2 3日CME抛出之后到达磁层前的一段时间,银河宇宙线的 2 2.61 5 4min的周期非常显著,而其他短时间周期的特征变得很不明显,几乎变为噪声水平。     

Numerical Simulation of Cosmic Structures

At first, the research project revealed that the clustering of small-mass dark halos in the universe is far stronger than what has been predicted analytically by the well known Press-Schechter (PS) theory, giving rise to a lot of theoretical studies to revise the PS theory. In this way, a precise formula was developed to predict the clustering of halos and by applying the result, the grouping of dark matter and galaxies are predicted. For the first time in the world, the scientists in charge of this project succeeded in developing a formula for logarithmic normal distribution of the dark halo's concentrating factor.     

羊八井宇宙线观测站ARGO实验进展状况

本文主要介绍了羊八井ARGO实验计划即全覆盖式阵列计划的进展状况及其所开展的宇宙线天体粒子物理学研究。     

羊八井天然水中氟的富集对人体健康的影响

氟中毒严重危害人体的健康,是世界上主要地方病之一。人体的健康与饮水有着密切的关系,因此,探讨氟在该区富集的规律,对寻找天然低氟水源、改善饮水环境和防治地方性氟中毒具有重要意义。     

基层农业技术推广体系构建及运行机制研究——基于河北省640个农户的调查分析

通过对河北省640个农户的调查,分析了基层农业技术推广体系存在问题.农业科研、教育和推广缺乏良性协作机制、推广机构对推广工作创新不够、推广队伍供给与务农劳动者需求偏差大、推广体系缺乏政府长期稳定支持、推广工作法律法规有待完善是问题成因.研究提出了推行有效技术推广服务方式、创新推广体系运行机制、建立公益性推广管理体制、完善推广经费保障政策、修改完善农业技术推广法律法规和建立多元化农业技术推广体系等政策建议.     

Water Cherenkov Detector Array at Large High-Altitude Air Shower Observatory Now in Operation

正Construction on the Water Cherenkov Detector Array (WCDA) at the Large High-Altitude Air Shower Observatory (LHAASO) has been completed and the array is now in operation as of the beginning of 2021,according to the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences (CAS).LHAASO is one of the country’s ST infrastructure mega projects.     

从宇宙射线数据到强子化的动力学机制

著名的日本 美国乳胶合作实验组的宇宙射线数据被用来展示,如何直接从实验数据出发,获得关于强子化的有用信息.结果显示,在强子化的过程中,自组织临界现象也被观察到了.这个事实预示着,强子化过程中潜在的动力学机制就是复杂系统中的BTW 雪崩动力学     

On the Generalization of Block Pulse Operational Matrices for Fractional and Operational Calculus

A more rigorous derivation for the generalized block pulse operational matrices is proposed in this paper. The Riemann-Liouville fractional integral for repeated fractional (and operational) integration is integrated exactly, then expanded in block pulse functions to yield the generalized block pulse operational matrices. The generalized block pulse operational matrices perform as s^-α(α\s>;0,α∈R) in the Laplace domain and as fractional (and operational) integrators in the time domain. Also, the generalized block pulse operational matrices of differentiation which correspond to s^α(α\s>;0,α∈R) in the Laplace domain are derived. Based on these results, the inversions of rational and irrational transfer functions are proposed in a simple, accurate and efficient way.     

Operational analysis of library systems

Mathematical models are developed for describing and optimizing the way libraries organize information sources. By ordering the sources in a more relevant manner, the users' search and retrieval costs are reduced, which leads to an increase in the value and amount of information processed. The cost of organizing collections so as to minimize user effort is dependent on the scatter of relevant sources in the literature and the specification of core classes.     

加速度检测仪数据校正

本文讨论声屏障检测仪检测振动加速度的误差分析、仿真研究、校正,并计算声屏障振动的速度、位移,利用机理分析法建立数学模型求解。问题一:先用matlab绘出原始数据图像,然后通过梯形积分方法,求得声屏障的速度、位移和对应的图像;通过matlab的Jarque-Bera正态检验算法,将图像与题目中所给理想状态下曲线进行比较分析,求得随机误差、系统误差对测量结果的影响程度。问题二:首先采用滑动平均滤波法消除随机误差,对积分后的信号采用LMS算法对误差趋势项分别进行一次拟合与二次拟合,求出拟合表达式,然后进行波形修正得到正确的速度和位移图像,最后通过图像验证计算结果。问题三可尝试用在医学信号处理等方面。     

极限的四则运算法则

极限的四则运算法则,是学生在学习了极限的概念、无穷小量与无穷大量之后的又一个重要内容.它扩大了求极限的范围,是以后继续学习导数和微分等内容的重要基础知识.本节的内容公式不多,容易记忆,但具体运用时,情况千差万别,容易使学生产生课堂上听得清楚明白,课后自己不会解题的现象.所以在讲授过程中,要把具体内容分清类型、分析透彻、讲解明白,使学生在自己动手时有章可循,能够灵活运用极限的四则运算法则求较复杂函数的极限.