The wave equation of the electron, recently improved, allows physics to obtain all the quantum numbers and other results explaining the hydrogen spectrum. The Pauli exclusion principle then gives the description of el...The wave equation of the electron, recently improved, allows physics to obtain all the quantum numbers and other results explaining the hydrogen spectrum. The Pauli exclusion principle then gives the description of electron clouds used in chemistry. The relativistic wave equation is associated with a Lagrangian density, thus also with an energy-momentum tensorial density. The wave of an electron cloud adds these energy-momentum densities, while photons in light are precisely those differences between such energy-momentum densities.展开更多
Electron cloud interaction with high energy positive beams are believed responsible for various undesirable effects such as vacuum degradation, collective beam instability and even beam loss in high power proton circu...Electron cloud interaction with high energy positive beams are believed responsible for various undesirable effects such as vacuum degradation, collective beam instability and even beam loss in high power proton circular accelerators. An important uncertainty in predicting electron cloud instability lies in the detailed processes of the generation and accumulation of the electron cloud. The simulation on the build-up of electron cloud is necessary to further studies on beam instability caused by electron clouds. The China Spallation Neutron Source （CSNS） is an intense proton accelerator facility now being built, whose accelerator complex includes two main parts： an H-linac and a rapid cycling synchrotron （RCS）. The RCS accumulates the 80 MeV proton beam and accelerates it to 1.6 GeV with a repetition rate of 25 Hz. During beam injection with lower energy, the emerging electron cloud may cause serious instability and beam loss on the vacuum pipe. A simulation code has been developed to simulate the build-up, distribution and density of electron cloud in CSNS/RCS.展开更多
Electron Cloud Instability has been studied in the operation of BEPC. The BEPCⅡ began the commissioning in November 2006 and the positron beam current has reached 500 mA. Because of such a high beam current, some ins...Electron Cloud Instability has been studied in the operation of BEPC. The BEPCⅡ began the commissioning in November 2006 and the positron beam current has reached 500 mA. Because of such a high beam current, some instabilities such as ECI, bunch lengthening et al, have appeared during the operation. The experimental investigation on ECI during the commissioning of BEPCⅡ will be reported in this paper.展开更多
In this paper we treat first some nonlinear beam dynamics problems in storage rings, such as beam dynamic apertures due to magnetic multipoles, wiggles, beam-beam effects, nonlinear space charge effect, and then nonli...In this paper we treat first some nonlinear beam dynamics problems in storage rings, such as beam dynamic apertures due to magnetic multipoles, wiggles, beam-beam effects, nonlinear space charge effect, and then nonlinear electron cloud effect combined with beam-beam and space charge effects, analytically. This analytical treatment is applied to BEPC II. The corresponding analytical expressions developed in this paper are useful both in understanding the physics behind these problems and also in making practical quick hand estimations.展开更多
Since the position of the electron in a hydrogen atom cannot be determined, the region in which it resides is said to be determined stochastically and forms an electron cloud. The probability density function of the s...Since the position of the electron in a hydrogen atom cannot be determined, the region in which it resides is said to be determined stochastically and forms an electron cloud. The probability density function of the single electron in 1s orbit is expressed as φ2, a function of distance from the nucleus. However, the probability of existence of the electron is expressed as a radial distribution function at an arbitrary distance from the nucleus, so it is estimated as the probability of the entire spherical shape of that radius. In this study, it has been found that the electron existence probability approximates the radial distribution function by assuming that the probability of existence of the electron being in the vicinity of the nucleus follows a normal distribution for arbitrary x-, y-, and z-axis directions. This implies that the probability of existence of the electron, which has been known only from the distance information, would follow a normal distribution independently in the three directions. When the electrons’ motion is extremely restricted in a certain direction by the magnetic field of both tokamak and helical fusion reactors, the probability of existence of the electron increases with proximity to the nucleus, and as a result, it is less likely to be liberated from the nucleus. Therefore, more and more energy is required to free the nucleus from the electron in order to generate plasma.展开更多
环形加速器中,特别是强流正离子环形加速器中由于二次电子聚集而形成的电子云效应对高流强下的加速器运行会产生至关重要的影响。环形加速器中二次电子产生的主要原因在于初始电子在束流作用下获得能量,与束流真空管道内壁发生碰撞,如...环形加速器中,特别是强流正离子环形加速器中由于二次电子聚集而形成的电子云效应对高流强下的加速器运行会产生至关重要的影响。环形加速器中二次电子产生的主要原因在于初始电子在束流作用下获得能量,与束流真空管道内壁发生碰撞,如果此时真空室内壁材料的二次电子产额(Secondary Electron Yield,SEY)大于1,则会在束流管道内形成二次电子倍增而逐渐积累形成电子云。文章将结合国内近几年正离子环形加速器的设计建造参数(北京正负电子对撞机升级改造工程BEPCII、中国散裂中子源快循环同步加速器CSNS/RCS及下一代环形正负电子对撞机计划CEPC),通过二次电子产生的物理机制分析、理论计算及仿真模拟对其产生、运动、聚集及平衡过程进行研究,探索二次电子发射系数对电子云密度的影响,进而提出降低环形加速器中电子云密度的方法。展开更多
常规的医院档案电子信息自动管理平台主要使用HTMLPHP(Hyper Text Markup LanguageHypertext Preprocessor)超文本预处理语言生成多选项表单,易受服务器Post混乱作用的影响,导致综合运行性能低下,因此,提出一种基于NAS私有云的医院档案...常规的医院档案电子信息自动管理平台主要使用HTMLPHP(Hyper Text Markup LanguageHypertext Preprocessor)超文本预处理语言生成多选项表单,易受服务器Post混乱作用的影响,导致综合运行性能低下,因此,提出一种基于NAS私有云的医院档案电子信息自动管理平台。硬件部分设计HGYUI4033处理芯片和KLOPA1存储器,软件部分利用NAS搭建档案电子信息管理私有云,生成档案电子信息自动管理架构,从而实现电子档案信息的自动管理。平台测试结果表明,文章设计的医院档案电子信息自动管理平台在不同状态下均能有序运行,综合性能良好,具有可靠性,有一定的应用价值,为提高档案综合管理效率、实现档案数字化管理升级作出一定的贡献。展开更多
文摘The wave equation of the electron, recently improved, allows physics to obtain all the quantum numbers and other results explaining the hydrogen spectrum. The Pauli exclusion principle then gives the description of electron clouds used in chemistry. The relativistic wave equation is associated with a Lagrangian density, thus also with an energy-momentum tensorial density. The wave of an electron cloud adds these energy-momentum densities, while photons in light are precisely those differences between such energy-momentum densities.
基金Supported by National Natural Science Foundation of China(11275221,11175193)
文摘Electron cloud interaction with high energy positive beams are believed responsible for various undesirable effects such as vacuum degradation, collective beam instability and even beam loss in high power proton circular accelerators. An important uncertainty in predicting electron cloud instability lies in the detailed processes of the generation and accumulation of the electron cloud. The simulation on the build-up of electron cloud is necessary to further studies on beam instability caused by electron clouds. The China Spallation Neutron Source （CSNS） is an intense proton accelerator facility now being built, whose accelerator complex includes two main parts： an H-linac and a rapid cycling synchrotron （RCS）. The RCS accumulates the 80 MeV proton beam and accelerates it to 1.6 GeV with a repetition rate of 25 Hz. During beam injection with lower energy, the emerging electron cloud may cause serious instability and beam loss on the vacuum pipe. A simulation code has been developed to simulate the build-up, distribution and density of electron cloud in CSNS/RCS.
基金Supported by National Natural Science Foundation of China (10605032)
文摘Electron Cloud Instability has been studied in the operation of BEPC. The BEPCⅡ began the commissioning in November 2006 and the positron beam current has reached 500 mA. Because of such a high beam current, some instabilities such as ECI, bunch lengthening et al, have appeared during the operation. The experimental investigation on ECI during the commissioning of BEPCⅡ will be reported in this paper.
文摘In this paper we treat first some nonlinear beam dynamics problems in storage rings, such as beam dynamic apertures due to magnetic multipoles, wiggles, beam-beam effects, nonlinear space charge effect, and then nonlinear electron cloud effect combined with beam-beam and space charge effects, analytically. This analytical treatment is applied to BEPC II. The corresponding analytical expressions developed in this paper are useful both in understanding the physics behind these problems and also in making practical quick hand estimations.
文摘Since the position of the electron in a hydrogen atom cannot be determined, the region in which it resides is said to be determined stochastically and forms an electron cloud. The probability density function of the single electron in 1s orbit is expressed as φ2, a function of distance from the nucleus. However, the probability of existence of the electron is expressed as a radial distribution function at an arbitrary distance from the nucleus, so it is estimated as the probability of the entire spherical shape of that radius. In this study, it has been found that the electron existence probability approximates the radial distribution function by assuming that the probability of existence of the electron being in the vicinity of the nucleus follows a normal distribution for arbitrary x-, y-, and z-axis directions. This implies that the probability of existence of the electron, which has been known only from the distance information, would follow a normal distribution independently in the three directions. When the electrons’ motion is extremely restricted in a certain direction by the magnetic field of both tokamak and helical fusion reactors, the probability of existence of the electron increases with proximity to the nucleus, and as a result, it is less likely to be liberated from the nucleus. Therefore, more and more energy is required to free the nucleus from the electron in order to generate plasma.
文摘环形加速器中,特别是强流正离子环形加速器中由于二次电子聚集而形成的电子云效应对高流强下的加速器运行会产生至关重要的影响。环形加速器中二次电子产生的主要原因在于初始电子在束流作用下获得能量,与束流真空管道内壁发生碰撞,如果此时真空室内壁材料的二次电子产额(Secondary Electron Yield,SEY)大于1,则会在束流管道内形成二次电子倍增而逐渐积累形成电子云。文章将结合国内近几年正离子环形加速器的设计建造参数(北京正负电子对撞机升级改造工程BEPCII、中国散裂中子源快循环同步加速器CSNS/RCS及下一代环形正负电子对撞机计划CEPC),通过二次电子产生的物理机制分析、理论计算及仿真模拟对其产生、运动、聚集及平衡过程进行研究,探索二次电子发射系数对电子云密度的影响,进而提出降低环形加速器中电子云密度的方法。
文摘常规的医院档案电子信息自动管理平台主要使用HTMLPHP(Hyper Text Markup LanguageHypertext Preprocessor)超文本预处理语言生成多选项表单,易受服务器Post混乱作用的影响,导致综合运行性能低下,因此,提出一种基于NAS私有云的医院档案电子信息自动管理平台。硬件部分设计HGYUI4033处理芯片和KLOPA1存储器,软件部分利用NAS搭建档案电子信息管理私有云,生成档案电子信息自动管理架构,从而实现电子档案信息的自动管理。平台测试结果表明,文章设计的医院档案电子信息自动管理平台在不同状态下均能有序运行,综合性能良好,具有可靠性,有一定的应用价值,为提高档案综合管理效率、实现档案数字化管理升级作出一定的贡献。
