The spatiotemporal evolutions of a one-dimensional collisionless decaying plasma bounded by two electrodes with an externally applied electrostatic field are studied by theoretical analyses and particle-in-cell(PIC)si...The spatiotemporal evolutions of a one-dimensional collisionless decaying plasma bounded by two electrodes with an externally applied electrostatic field are studied by theoretical analyses and particle-in-cell(PIC)simulations with the ion extraction process in a laser-induced plasma as the major research background.Based on the theoretical analyses,the transport process of the charged particles including electrons and ions can be divided into three stages:electron oscillation and ion matrix sheath extraction stage,sheath expansion and ion rarefaction wave propagation stage and the plasma collapse stage,and the corresponding criterion for each stage is also presented.Consequently,a complete analytical model is established for describing the ion extraction flux at each stage during the decaying of the laser-induced plasmas under an electrostatic field,which is also validated by the PIC modeling results.Based on this analytical model,influences of the key physical parameters,including the initial electron temperature and number density,plasma width and the externally applied electric voltage,on the ratio of the extracted ions are predicted.The calculated results show that a higher applied electric potential,smaller initial plasma number density and plasma width lead to a higher ratio of the extracted ions during the first stage;while in this stage,the initial electron temperature shows little effect on it.Meanwhile,more ions will be extracted before the plasma collapse once a higher electric potential is applied.The theoretical model presented in this paper is helpful not only for a deep understanding to the charged particle transport mechanisms for a bounded decaying plasma under an applied electrostatic field,but also for an optimization of the ion extraction process in practical applications.展开更多
The kinetics of electron transmission at solid/solid interface system are investigation and studied using a simple model that derives depending on the quantum consideration. A two quantum state for donor state ｜αn ...The kinetics of electron transmission at solid/solid interface system are investigation and studied using a simple model that derives depending on the quantum consideration. A two quantum state for donor state ｜αn 〉 and acceptor state ｜αA 〉 are supposed. Marcus-Hush semi classical continuum levels theory adapted to evaluated the energies for orientation before transfer. The probability of transmission of electron is calculated to investigation the kinetics of transfer. Our result for calculation of rate constant of electron transfer shows a good agreement with experiment data.展开更多
With a long history, the South Silk Road has been and will continue to be an important corridor of economic, political, cultural and religious exchange between Southwest China and Southeast Asia, South Asia, the Middl...With a long history, the South Silk Road has been and will continue to be an important corridor of economic, political, cultural and religious exchange between Southwest China and Southeast Asia, South Asia, the Middle East, West Asia and Europe. The transportation corridor established by the South Silk Road has both important strategic significance and value for China's transportation safety, and the potential to bring huge political and economic benefits to our country. However, all kinds of challenges and threats need to be dealt with in order for it to achieve strategic value and play the role of a transportation corridor, thereby ensuring China's strategic security.展开更多
在全面推广高速公路差异化收费背景下,针对如何选取差异化收费路段的问题,建立一种基于多源数据的差异化收费路段识别方法.首先,基于高速公路门架数据、收费站出入口流量、普通国省道交通流量自动观测站数据等多源数据,从路段沿线社会...在全面推广高速公路差异化收费背景下,针对如何选取差异化收费路段的问题,建立一种基于多源数据的差异化收费路段识别方法.首先,基于高速公路门架数据、收费站出入口流量、普通国省道交通流量自动观测站数据等多源数据,从路段沿线社会经济发展水平、网络化水平、交通运行特征、交通可转移性、交通负荷均衡性5个维度,构建高速公路差异化收费路段识别指标体系.然后,基于k-means聚类和分类回归树算法(Classification and Regression Trees,CART)建立高速公路差异化收费路段识别模型.最后,以云南省130条高速公路路段为例,提取高速公路差异化收费路段细分规则及关键特征指标.研究结果表明:影响高速公路差异化收费路段细分的关键特征指标分别为路段成网率、收费站节点度、出行成本偏差率、路段全天小时拥挤度、可替代路径数量;根据决策树细分规则可将差异化收费路段划分为差异化上浮型、不适合差异化、差异化下浮型3种,符合高速公路实际收费运营情况.展开更多
为分析化学品船智能液货系统的安全性,采用系统理论事故模型与过程(System-Theoretic Accident Model and Processes, STAMP)方法,构建了化学品船智能液货系统控制反馈模型;基于系统理论过程分析(System-Theoretic Process Analysis, ST...为分析化学品船智能液货系统的安全性,采用系统理论事故模型与过程(System-Theoretic Accident Model and Processes, STAMP)方法,构建了化学品船智能液货系统控制反馈模型;基于系统理论过程分析(System-Theoretic Process Analysis, STPA),确定系统级事故,识别不安全控制行为并分析不安全控制行为关键致因;将不安全控制行为作为风险因素,利用三角模糊数对不安全控制行为风险进行量化。结果表明,26种不安全控制行为中,泵管阀动态调节、人员监测、数据采集、货品相容性判定等因素对风险影响程度较高。该分析结果可为化学品船智能液货系统的应用和安全管理提供参考。展开更多
基金the National Natural Science Foundation of China(Grant No.11775128)。
文摘The spatiotemporal evolutions of a one-dimensional collisionless decaying plasma bounded by two electrodes with an externally applied electrostatic field are studied by theoretical analyses and particle-in-cell(PIC)simulations with the ion extraction process in a laser-induced plasma as the major research background.Based on the theoretical analyses,the transport process of the charged particles including electrons and ions can be divided into three stages:electron oscillation and ion matrix sheath extraction stage,sheath expansion and ion rarefaction wave propagation stage and the plasma collapse stage,and the corresponding criterion for each stage is also presented.Consequently,a complete analytical model is established for describing the ion extraction flux at each stage during the decaying of the laser-induced plasmas under an electrostatic field,which is also validated by the PIC modeling results.Based on this analytical model,influences of the key physical parameters,including the initial electron temperature and number density,plasma width and the externally applied electric voltage,on the ratio of the extracted ions are predicted.The calculated results show that a higher applied electric potential,smaller initial plasma number density and plasma width lead to a higher ratio of the extracted ions during the first stage;while in this stage,the initial electron temperature shows little effect on it.Meanwhile,more ions will be extracted before the plasma collapse once a higher electric potential is applied.The theoretical model presented in this paper is helpful not only for a deep understanding to the charged particle transport mechanisms for a bounded decaying plasma under an applied electrostatic field,but also for an optimization of the ion extraction process in practical applications.
文摘The kinetics of electron transmission at solid/solid interface system are investigation and studied using a simple model that derives depending on the quantum consideration. A two quantum state for donor state ｜αn 〉 and acceptor state ｜αA 〉 are supposed. Marcus-Hush semi classical continuum levels theory adapted to evaluated the energies for orientation before transfer. The probability of transmission of electron is calculated to investigation the kinetics of transfer. Our result for calculation of rate constant of electron transfer shows a good agreement with experiment data.
基金The National Social Science Fund,West Project(12XGL013)Sichuan Science and Technology Department,Soft Science Project(20136RW0120)+1 种基金Sichuan Development Research Center of Oil and Gas Project(Sichuan Oil and Gas Science SKB15-02)Southwest Petroleum University,Youth Teacher Academic Project(201499010101)
文摘With a long history, the South Silk Road has been and will continue to be an important corridor of economic, political, cultural and religious exchange between Southwest China and Southeast Asia, South Asia, the Middle East, West Asia and Europe. The transportation corridor established by the South Silk Road has both important strategic significance and value for China's transportation safety, and the potential to bring huge political and economic benefits to our country. However, all kinds of challenges and threats need to be dealt with in order for it to achieve strategic value and play the role of a transportation corridor, thereby ensuring China's strategic security.
文摘在全面推广高速公路差异化收费背景下,针对如何选取差异化收费路段的问题,建立一种基于多源数据的差异化收费路段识别方法.首先,基于高速公路门架数据、收费站出入口流量、普通国省道交通流量自动观测站数据等多源数据,从路段沿线社会经济发展水平、网络化水平、交通运行特征、交通可转移性、交通负荷均衡性5个维度,构建高速公路差异化收费路段识别指标体系.然后,基于k-means聚类和分类回归树算法(Classification and Regression Trees,CART)建立高速公路差异化收费路段识别模型.最后,以云南省130条高速公路路段为例,提取高速公路差异化收费路段细分规则及关键特征指标.研究结果表明:影响高速公路差异化收费路段细分的关键特征指标分别为路段成网率、收费站节点度、出行成本偏差率、路段全天小时拥挤度、可替代路径数量;根据决策树细分规则可将差异化收费路段划分为差异化上浮型、不适合差异化、差异化下浮型3种,符合高速公路实际收费运营情况.
文摘为分析化学品船智能液货系统的安全性,采用系统理论事故模型与过程(System-Theoretic Accident Model and Processes, STAMP)方法,构建了化学品船智能液货系统控制反馈模型;基于系统理论过程分析(System-Theoretic Process Analysis, STPA),确定系统级事故,识别不安全控制行为并分析不安全控制行为关键致因;将不安全控制行为作为风险因素,利用三角模糊数对不安全控制行为风险进行量化。结果表明,26种不安全控制行为中,泵管阀动态调节、人员监测、数据采集、货品相容性判定等因素对风险影响程度较高。该分析结果可为化学品船智能液货系统的应用和安全管理提供参考。
