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慢性荨麻疹患者血清PAF、抗-CCD IgE水平变化及临床意义分析
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作者 李椅云 毕超 +2 位作者 梁艳华 廖子青 梁碧华 《中国卫生标准管理》 2024年第18期75-78,共4页
目的探讨慢性荨麻疹患者血清血小板活化因子(platelet activating factor,PAF)、抗交叉反应性糖类决定簇免疫球蛋白E(anti-cross reactive carbohydrate determinants immunoglobulin E,抗-CCD IgE)水平变化及临床意义,为临床诊断及病... 目的探讨慢性荨麻疹患者血清血小板活化因子(platelet activating factor,PAF)、抗交叉反应性糖类决定簇免疫球蛋白E(anti-cross reactive carbohydrate determinants immunoglobulin E,抗-CCD IgE)水平变化及临床意义,为临床诊断及病情程度、预后评估提供参考依据。方法选取2021年5月—2023年5月广州市皮肤病防治所收治的100例慢性荨麻疹患者,根据荨麻疹活动评分分为轻度组(n=41)、中度组(n=35)和重度组(n=24)。采集患者空腹静脉血,通过酶联免疫吸附法测定血清PAF水平,通过斑点免疫印迹法测定抗-CCD IgE、过敏原特异性免疫球蛋白E(specific immunoglobulin E,sIgE)。比较不同病情程度慢性荨麻疹患者血清PAF水平,分析慢性荨麻疹患者血清PAF水平与荨麻疹活动评分相关性,比较不同临床特征慢性荨麻疹患者抗-CCD IgE阳性率。结果中度组、重度组患者血清PAF水平高于轻度组,重度组患者血清PAF水平高于中度组,差异有统计学意义(P<0.05)。Pearson相关分析结果显示,慢性荨麻疹患者血清PAF水平与荨麻疹活动评分呈正相关性(r=0.491,P<0.001)。年龄≥45岁、重度病情、sIgE阳性患者抗-CCD IgE阳性率高于年龄<45岁、轻度病情、sIgE阴性患者,差异有统计学意义(P<0.05)。抗-CCD IgE阳性患者中过敏原阳性最高的为尘螨组合(66.67%),其次为蟑螂、螃蟹、普通豚草,分别为55.56%、44.44%和44.44%。结论慢性荨麻疹患者血清PAF水平与病情密切相关,且抗-CCD IgE水平与sIgE水平有一定关系,抗-CCD IgE阳性表达情况对sIgE试验存在一定干扰,分析试验结果时应考虑抗-CCD IgE的影响。 展开更多
关键词 慢性荨麻疹 抗交叉反应性糖类决定簇免疫球蛋白E 血小板活化因子 免疫球蛋白E 水平变化 临床意义
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Level crossing in a two-photon Jaynes-Cummings model 被引量:3
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作者 任学藻 丛红璐 +1 位作者 廖旭 黎雷 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期279-282,共4页
In this paper,the energy spectrum of the two-photon Jaynes-Cummings model(TPJCM) is calculated exactly in the non-rotating wave approximation(non-RWA),and we study the level-crossing problem by means of fidelity.A... In this paper,the energy spectrum of the two-photon Jaynes-Cummings model(TPJCM) is calculated exactly in the non-rotating wave approximation(non-RWA),and we study the level-crossing problem by means of fidelity.A narrow peak of the fidelity is observed at the level-crossing point,which does not appear at the avoided-crossing point.Therefore fidelity is perfectly suited for detecting the level-crossing point in the energy spectrum. 展开更多
关键词 level crossing FIDELITY two-photon Jaynes-Cummings model
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中国跨境服务贸易负面清单经济效应分析--以上海为例 被引量:2
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作者 张娟 李计广 王红梅 《科学决策》 2024年第2期39-61,共23页
文章基于2010-2021年省际面板数据,通过合成控制法,计量分析了跨境服务贸易负面清单对上海服务业发展水平的影响。研究发现,跨境服务贸易负面清单制度对上海服务业发展水平具有一定的促进作用,并且这一结论经过一系列稳健性检验之后依... 文章基于2010-2021年省际面板数据,通过合成控制法,计量分析了跨境服务贸易负面清单对上海服务业发展水平的影响。研究发现,跨境服务贸易负面清单制度对上海服务业发展水平具有一定的促进作用,并且这一结论经过一系列稳健性检验之后依然成立。机制分析发现,跨境服务贸易负面清单可以通过市场化水平、政府干预、地区数字化水平等方式作用于服务业发展水平。 展开更多
关键词 跨境服务贸易负面清单 高标准经贸规则 服务业发展水平 合成控制法
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Buckling Optimization of Curved Grid Stiffeners through the Level Set Based Density Method
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作者 Zhuo Huang Ye Tian +2 位作者 Yifan Zhang Tielin Shi Qi Xia 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期711-733,共23页
Stiffened structures have great potential for improvingmechanical performance,and the study of their stability is of great interest.In this paper,the optimization of the critical buckling load factor for curved grid s... Stiffened structures have great potential for improvingmechanical performance,and the study of their stability is of great interest.In this paper,the optimization of the critical buckling load factor for curved grid stiffeners is solved by using the level set based density method,where the shape and cross section(including thickness and width)of the stiffeners can be optimized simultaneously.The grid stiffeners are a combination ofmany single stiffenerswhich are projected by the corresponding level set functions.The thickness and width of each stiffener are designed to be independent variables in the projection applied to each level set function.Besides,the path of each single stiffener is described by the zero iso-contour of the level set function.All the single stiffeners are combined together by using the p-norm method to obtain the stiffener grid.The proposed method is validated by several numerical examples to optimize the critical buckling load factor. 展开更多
关键词 STIFFENER buckling optimization shape and cross section level set based density
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Deformation Evolution Characteristics Revealed by GPS and Cross-fault Leveling Data before the M_S8. 0 Wenchuan Earthquake
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作者 ZHAO Jing LIU Jie +2 位作者 REN Jinwei YUE Chong LI Jiaojiao 《Earthquake Research in China》 CSCD 2019年第3期461-477,共17页
Based on GPS velocity during 1999-2007,GPS baseline time series on large scale during1999-2008 and cross-fault leveling data during 1985-2008,the paper makes some analysis and discussion to study and summarize the mov... Based on GPS velocity during 1999-2007,GPS baseline time series on large scale during1999-2008 and cross-fault leveling data during 1985-2008,the paper makes some analysis and discussion to study and summarize the movement,tectonic deformation and strain accumulation evolution characteristics of the Longmenshan fault and the surrounding area before the MS8. 0 Wenchuan earthquake,as well as the possible physical mechanism late in the seismic cycle of the Wenchuan earthquake. Multiple results indicate that:GPS velocity profiles show that obvious continuous deformation across the eastern Qinghai-Tibetan Plateau before the earthquake was distributed across a zone at least 500 km wide,while there was little deformation in Sichuan Basin and Longmenshan fault zone,which means that the eastern Qinghai-Tibetan Plateau provides energy accumulation for locked Longmenshan fault zone continuously. GPS strain rates show that the east-west compression deformation was larger in the northwest of the mid-northern segment of the Longmenshan fault zone,and deformation amplitude decreased gradually from far field to near fault zone,and there was little deformation in fault zone. The east-west compression deformation was significant surrounding the southwestern segment of the Longmenshan fault zone,and strain accumulation rate was larger than that of mid-northern segment.Fault locking indicates nearly whole Longmenshan fault was locked before the earthquake except the source of the earthquake which was weakly locked,and a 20 km width patch in southwestern segment between 12 km to 22. 5 km depth was in creeping state. GPS baseline time series in northeast direction on large scale became compressive generally from 2005 in the North-South Seismic Belt,which reflects that relative compression deformation enhances. The cross-fault leveling data show that annual vertical change rate and deformation trend accumulation rate in the Longmenshan fault zone were little,which indicates that vertical activity near the fault was very weak and the fault was tightly locked. According to analyses of GPS and cross-fault leveling data before the Wenchuan earthquake,we consider that the Longmenshan fault is tightly locked from the surface to the deep,and the horizontal and vertical deformation are weak surrounding the fault in relatively small-scale crustal deformation. The process of weak deformation may be slow,and weak deformation area may be larger when large earthquake is coming. Continuous and slow compression deformation across eastern Qinghai-Tibetan Plateau before the earthquake provides dynamic support for strain accumulation in the Longmenshan fault zone in relative large-scale crustal deformation. 展开更多
关键词 MS8.0 WENCHUAN earthquake GPS DATA cross-FAULT leveling DATA Fault locking Block DEFORMATION
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The Influence of Thrust Fault Structure on Cross-fault Short-leveling Survey
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作者 YUE Chong QU Chunyan +2 位作者 YAN Wei ZHAO Jing SU Qin 《Earthquake Research in China》 CSCD 2019年第3期489-502,共14页
Aiming at different variation patterns of cross-fault short-leveling before earthquakes,the paper establishes the 2-D finite-element models with different crustal stratification and fault occurrence perpendicular to L... Aiming at different variation patterns of cross-fault short-leveling before earthquakes,the paper establishes the 2-D finite-element models with different crustal stratification and fault occurrence perpendicular to Longmenshan fault zone. By contact analysis and viscoelastic finite element method,the influence of fault structure on cross-fault short-leveling is obtained under the same constraint conditions,the results show that:with the increase of the horizontal projection distance of fault,the cumulative displacements of surface increase gradually in the models with fixed dip angles of the fault plane(model 1). However,when the horizontal projection distance exceeds 20 km,the influence of fault?s dip angle on the cumulative displacements of surface short-leveling will decrease significantly,and the cumulative displacements are maintained at about 1. 5 m. However,in the listric fault models(model 2),when the projection distance is less than 20 km,the listric fault structure impedes the sliding of fault. The short-leveling variation rate is only half of model 1;as a result,the ability to reflect the regional stress enhancement by cross-fault short-leveling is further weakened. But when the horizontal projection distance exceeds25 km,the cumulative displacements significantly increase,with the maximum displacement reaching 1. 75 m. The results of equivalent stress show that the listric fault structure causes a sudden increasement in equivalent stress when the horizontal projection distance is 10 km,higher equivalent stress values are accumulated between the projection distance of 5-20 km,and then high-low stress difference zones are formed at the bottom of the fault plane and near the transition zone of low-high dip angle. 展开更多
关键词 cross-FAULT short-leveling FINITE element Listric FAULT STRUCTURE EQUIVALENT stress
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数字化服务水平对中国-东盟双边贸易的影响分析
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作者 田敏 《中国商论》 2024年第16期66-69,共4页
在数字化浪潮席卷全球经济背景下,本文旨在深入探讨东盟国家数字化服务水平对其与中国双边贸易额的影响,以及此影响如何通过不同机制发挥作用。本文通过采集中国与10个东盟国家2012—2022年双边贸易面板数据,实证检验数字化服务水平对中... 在数字化浪潮席卷全球经济背景下,本文旨在深入探讨东盟国家数字化服务水平对其与中国双边贸易额的影响,以及此影响如何通过不同机制发挥作用。本文通过采集中国与10个东盟国家2012—2022年双边贸易面板数据,实证检验数字化服务水平对中国-东盟双边贸易的影响。结果显示,东盟国家数字化服务水平显著正向影响其与中国之间双边贸易额,东盟国家数字化服务水平每提升一单位,与中国双边贸易额平均可提升约21.17%。 展开更多
关键词 数字化服务水平 双边贸易 东盟国家 跨境贸易 国际贸易
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Safety Assessment of Closed-Loop Level Crossing Control Systems by Means of STAMP(Systems-Theoretic Accident Model and Processes)
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作者 Tetsuya TAKATA Akira ASANO Hideo NAKAMURA 《Journal of Traffic and Transportation Engineering》 2018年第5期241-254,共14页
There have been a large number of accidents at level crossings of railways and this has been considered to be a significant issue to be solved for the realization of safe and stable railway transport.A conventional le... There have been a large number of accidents at level crossings of railways and this has been considered to be a significant issue to be solved for the realization of safe and stable railway transport.A conventional level crossing control system is characterized by the use of two types of electronic train detectors;one detects a train approaching to a level crossing section and the other then detects the train having left the level crossing.By contrast,closed-loop level crossing control systems in which level crossing control equipment and train-borne equipment communicate with each other have been advocated and are expected to serve as an effective solution to the abovementioned issue.This paper describes the following three types of closed-loop level crossing control systems:decentralized level crossing control system,fully-centralized comprehensive level crossing control system and fully-centralized individual level crossing control system.This paper then assesses the safety of these systems in comparison to the conventional level crossing control system.For the purpose of the assessment of their safety,a new accident analysis model called STAMP(systems theoretic accident model and processes)that is suitable for software intensive systems is used to clarify the advantage of the proposed three types of level crossing control systems in terms of safety. 展开更多
关键词 level crossING CONTROL railway signaling closed loop CONTROL method safety assessment STAMP
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Mechanisms for Cross-Scaling, Flexibility and Social Learning in Building Resilience to Sea Level Rise: Case Study of Hampton Roads, Virginia 被引量:1
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作者 Carol Considine Michelle Covi Juita-Elena (Wie) Yusuf 《American Journal of Climate Change》 2017年第2期385-402,共18页
This case study examines how the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project, a whole-of-government and whole-of-community approach to planning for and adapting to... This case study examines how the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project, a whole-of-government and whole-of-community approach to planning for and adapting to sea level rise, addressed coastal resilience in a southeastern Virginia watershed that spans multiple jurisdictions. Meeting the challenge of sea level rise requires that actors across multiple sectors—citizens, community organizations, industry and government—understand the risks and work together to make critical decisions regarding adaptation strategies and actions. The case study area includes Little Creek Amphibious Base, which is bordered by the cities of Norfolk and Virginia Beach. Adaptation responses to sea level rise by the military base and the local governments will impact each other and the residents of the area, but no cooperative agreements are in place for a joint or collaborative response. This case study examines public and private infrastructure at risk, the infrastructure interdependencies, and mechanisms for providing collaborative solutions. Engagement of area residents and other stakeholders is also integral to the process of adaptation, which includes educating about sea level rise risk and provides a mechanism for social learning that enables stakeholders to participate in critical adaptation decisions. The case study demonstrates a method to improve resiliency in the case study area and inform a regional, multi-sectoral response to sea level rise adaptation strategies. 展开更多
关键词 Sea level RISE Multi-Sectoral Adaptation Hampton ROADS Critical Infrastructure Social Learning Socio-Ecological RESILIENCE cross-Scaling
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温玉铁路交叉并线区段GSM-R网络方案研究
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作者 李宝 《铁道通信信号》 2024年第2期47-53,共7页
温岭—玉环铁路在温岭站附近与甬台温线、杭绍台动走线存在交叉并线区段,在温岭线路所附近与甬台温线、杭绍台线、甬台温至杭绍台上/下行联络线存在交叉并线区段。首先,根据温玉铁路设计标准确定GSM-R网络采用单网交织覆盖方式,分别从... 温岭—玉环铁路在温岭站附近与甬台温线、杭绍台动走线存在交叉并线区段,在温岭线路所附近与甬台温线、杭绍台线、甬台温至杭绍台上/下行联络线存在交叉并线区段。首先,根据温玉铁路设计标准确定GSM-R网络采用单网交织覆盖方式,分别从设计原则、网络覆盖方式及电平要求、重叠覆盖区及时延计算等方面进行分析;其次,对交叉并线区段的GSM-R系统网络覆盖方案进行研究,深入比较不同GSM-R系统网络覆盖设计方案的优缺点,从不同铁路列控等级、交叉并线区段路网类型两方面进行对比,分别为温岭站、温岭线路所交叉并线区段制定出详细设计方案;最后,通过专用仿真软件对基站覆盖有效电平、基站覆盖重叠区域进行模拟仿真。仿真结果表明,交叉并线区段GSM-R网络覆盖电平满足在95%的地点和时间统计概率下,接收机输入端最小可用接收电平不小于-92 dBm的要求,为确定类似铁路区段GSM-R网络方案提供借鉴。 展开更多
关键词 温玉铁路 铁路数字移动通信系统 交叉并线区段 单网交织 网络覆盖 接收电平
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LEVEL SET输运方程的求解方法及其对气-液两相流运动界面数值模拟的影响 被引量:10
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作者 李会雄 邓晟 +2 位作者 赵建福 陈听宽 王飞 《核动力工程》 EI CAS CSCD 北大核心 2005年第3期242-248,267,共8页
用数值模拟方法来研究气-液两相流动与传热现象是当今多相流领域的一个热门课题。由于两相流固有的复杂性,气-液两相流界面迁移现象的数值模拟一直是两相流研究中的一大难点。本文介绍了捕捉气-液两相流相界面运动的水平集方法(LevelSet... 用数值模拟方法来研究气-液两相流动与传热现象是当今多相流领域的一个热门课题。由于两相流固有的复杂性,气-液两相流界面迁移现象的数值模拟一直是两相流研究中的一大难点。本文介绍了捕捉气-液两相流相界面运动的水平集方法(LevelSet)及其研究进展,介绍了求解LevelSet输运方程的3种方法,即一般差分格式、Superbee-TVD格式和Runge-Kutta法-5阶WENO组合格式。结合主流场的求解,分别用这3种方法对4种典型相界面在5种流场中的迁移特性进行了模拟计算,并对计算结果进行了比较和分析。结果表明,Runge-Kutta法-5阶WENO组合格式求解LevelSet输运方程的效果最好,在以后的计算中将主要采用这种组合格式来进行气-液相界面输运方程的求解。 展开更多
关键词 运动界面 level SET方法 -液两相流 5阶WENO格式 Superbee-TVD格式
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基于HLM-BP的高海拔隧道施工人员不安全行为预警研究 被引量:7
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作者 莫俊文 王锐锐 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2023年第3期1116-1126,共11页
为降低高海拔隧道工程人因失误导致的安全事故率,以西成铁路甘青隧道为例,对施工人员不安全行为进行预警研究。首先,对施工人员进行深度访谈,采用扎根理论对访谈数据进行编码处理,总结出高海拔隧道施工人员不安全行为诱发因素。其次,依... 为降低高海拔隧道工程人因失误导致的安全事故率,以西成铁路甘青隧道为例,对施工人员不安全行为进行预警研究。首先,对施工人员进行深度访谈,采用扎根理论对访谈数据进行编码处理,总结出高海拔隧道施工人员不安全行为诱发因素。其次,依据人境交互理论将不安全行为诱发因素划分为自变量、中介变量和因变量,运用HLM模型探讨跨层次下变量间复杂作用关系。最后,运用Matlab中BP神经网络工具箱函数进行编程,构建高海拔隧道施工人员不安全行为“11-10-5”三级预警模型,对其进行网络训练和数据拟合,识别不安全行为趋势,发出预警信号。结果表明,训练好的BP神经网络具有良好的预警能力,甘青隧道施工人员不安全行为等级总体处于较低水平,隧道施工安全管理状态良好;对不安全行为等级高的“重警”和“巨警”,逐层分析跨层次下的不安全行为诱发因素,提出加强安全教育培训、密切关注施工人员身心状态、加强高原习服训练以及实时监测隧道环境变化等靶向干预措施。研究引入跨层次因素分析机制,系统构建基于BP神经网络的高海拔隧道施工人员不安全行为预警模型,为不安全行为研究提供了新思路,同时也为降低高海拔隧道人因失误提供了参考建议。 展开更多
关键词 高海拔隧道 行为预警 BP神经网络 跨层次作用 扎根理论
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Variations of the Summer Somali and Australia Cross-Equatorial Flows and the Implications for the Asian Summer Monsoon 被引量:18
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作者 祝亚丽 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2012年第3期509-518,共10页
The temporal variations during 1948-2010 and vertical structures of the summer Somali and Australia cross-equatorial flows (CEFs) and the implications for the Asian summer monsoon were explored in this study. The st... The temporal variations during 1948-2010 and vertical structures of the summer Somali and Australia cross-equatorial flows (CEFs) and the implications for the Asian summer monsoon were explored in this study. The strongest southerly and northerly CEFs exist at 925 hPa and 150 hPa level, respectively. The low-level Somali (LLS) CEFs were significantly connected with the rainfall in most regions of India (especially the monsoon regions), except in a small area in southwest India. In comparison to the climatology, the low- level Australia (LLA) CEFs exhibited stronger variations at interannual time scale and are more closely connected to the East Asian summer monsoon circulation than to the LLS CEFs. The East Asian summer monsoon circulation anomalies related to stronger LLA CEFs were associ- ated with less water vapor content and less rainfall in the region between the middle Yellow River and Yangtze River and with more water vapor and more rainfall in southern China. The sea-surface tempera- ture anomalies east of Australia related to summer LLA CEFs emerge in spring and persist into summer, with implications for the seasonal prediction of summer rainfall in East Asia. The connection between the LLA CEFs and East Asian summer monsoon rainfall may be partly due to its linkage with E1 Nino-Southern Oscillation. In addition, both the LLA and LLS CEFs .exhibited interdecadal shifts in the late 1970s and the late 1990s, consistent with the phase shifts of Pacific Decadal Oscillation (PDO). 展开更多
关键词 cross-equatorial flow Asian summer monsoon low-level jet SOMALI
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Theoretical Analysis of Neutron Double-Differential Cross Section of n +^19F at 14.2 MeV 被引量:1
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作者 YAN Yu-Liang SUN Xiao-Jun +1 位作者 ZHANG Yue ZHANG Jing-Shang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第1期102-106,共5页
A new light nuclear reaction model has been developed and the double-differential measurements of lp shell nuclei have been analyzed successfully. Now, the application of this model is expanded to 19F of the 2s-ld she... A new light nuclear reaction model has been developed and the double-differential measurements of lp shell nuclei have been analyzed successfully. Now, the application of this model is expanded to 19F of the 2s-ld shell nucleus. The double-differential cross section of total outgoing neutron for n +^19F reactions at En=14.2 MeV has been calculated and analyzed, which agrees fairly well with the experimental measurements. In this paper, the contributions from different reaction channels to the double-differential cross sections have been analyzed in detail. The calculations indicate that this light nudear reaction model is also able to be used for the 2s-ld shell nucleus so long as the related level scheme couM be provided sufficiently. 展开更多
关键词 light nuclear reaction double-differential cross section pre-equillbrium emission discrete level
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Oxygen Isotope Records of Core 8KL of the South China Sea and Sea - level Change 被引量:1
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作者 Qian JianxingThe Second Institute of Oceanography, SO A, Hangzhuu, Zhejiang Liu Linqun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1995年第2期209-219,共11页
Based on a comparison between the oxygen isotope records of benthic and plank tonic foraminifers from core 8KL of the South China Sea and sea-level change records derived from the Huon Peninsula, New Guinea, it is fou... Based on a comparison between the oxygen isotope records of benthic and plank tonic foraminifers from core 8KL of the South China Sea and sea-level change records derived from the Huon Peninsula, New Guinea, it is found that both records are very similar from 72 K a B.P. to the present, especially for the benthic oxygen isotope record. The linear regression shows that δ18O changes (0.9995‰ for benthic foraminifers and 1.022‰ for planktonic foraminifers) are equal to 100 m in sea-level fluctuation. After making temperature correction in the δ18O record of benthic foraminifers from 72 to 120 Ka B.P., the curve of sea-level oscillation of the South China Sea since 186 Ka B.P. has been reconstructed. The lowermost sea - level that occurred in the last glacial maximum and oxygen isotope stage 6 is approximately - 130 m. 展开更多
关键词 oxygen isotopic records of foraminifera sea - level change linear regression
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Vertical deformation of the fault-crossing network around Baotou,observed by GPS
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作者 Qin Shanlan Du Weiji Ji Lingyun 《Geodesy and Geodynamics》 2013年第4期57-61,共5页
GPS data and precise leveling data of seismic network profiles across the fault in Baotou in 2006, 2009 and 2011 were processed and analyzed to test the feasibility of using GPS technology for fault-crossing vertical ... GPS data and precise leveling data of seismic network profiles across the fault in Baotou in 2006, 2009 and 2011 were processed and analyzed to test the feasibility of using GPS technology for fault-crossing vertical deformation monitoring. The results showed that high precision cross-fauh vertical deformation measurements can be obtained using appropriate GPS data processing strategies. 展开更多
关键词 fault-crossing precise leveling vertical deformation GPS vertical deviation mapping function
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Average Level Crossing Rate and Fading Duration of Multiuser Single Relay Cooperation Wireless Uplinks
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作者 贾向东 杨龙祥 朱洪波 《China Communications》 SCIE CSCD 2013年第4期135-143,共9页
We investigate the average Level Crossing Rate (LCR) and Average Fading Duration (AFD) of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed (i.ni.d) Ray- leig... We investigate the average Level Crossing Rate (LCR) and Average Fading Duration (AFD) of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed (i.ni.d) Ray- leigh fading channels. We first present the statistical analyses of the first-hop equivalent envelope. Then, we investigate the LCR and AFD of an equivalent end-to-end envelope, and present the closed-form solutions to LCR and AFD, which are given with integral forms. Finally, we derive the Laplace approximations of LCR and AFD as well as the upper and lower bounds. The numerical results of LCR show that the upper bound is tight. For multi user systems with different number of mobile users, the analyses indicate that the LCRs are approximately the same at the low level of the envelope. envelope However, there are at the high level of the reasonable differences among the curves of LCRs. Due to that fact that AFD is the inverse function of LCR, the results for AFD are the opposite. 展开更多
关键词 wireless communications multiuseruplinks level crossing rate average fadingduration
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Dirac R-matrix calculations of photoionization cross sections of Ni Ⅻ and atomic structure data of Ni
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作者 R T Nazirt M A Bari +3 位作者 M Bilal S Sardar M H Nasim M Salahuddin 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第2期127-140,共14页
We performed R-matrix calculations for photoionization cross sections of the two ground state configuration 3s^23p^5(~2P_(3/2,1/2)~o) levels and 12 excited states of Ni Ⅻ using relativistic Dirac Atomic R-matrix ... We performed R-matrix calculations for photoionization cross sections of the two ground state configuration 3s^23p^5(~2P_(3/2,1/2)~o) levels and 12 excited states of Ni Ⅻ using relativistic Dirac Atomic R-matrix Codes(DARC) across the photon energy range between the ionizations thresholds of the corresponding states and well above the thresholds of the last level of the Ni XIII target ion. Generally, a good agreement is obtained between our results and the earlier theoretical photoionization cross sections. Moreover, we have used two independent fully relativistic GRASP and FAC codes to calculate fine-structure energy levels, wavelengths, oscillator strengths, transitions rates among the lowest 48 levels belonging to the configuration(3s^23p^4, 3s3p^5, 3p^6, 3s^23p^33d) in Ni XIII. Additionally, radiative lifetimes of all the excited states of Ni XIII are presented. Our results of the atomic structure of Ni XIII show good agreement with other theoretical and experimental results available in the literature. A good agreement is found between our calculated lifetimes and the experimental ones.Our present results are useful for plasma diagnostic of fusion and astrophysical plasmas. 展开更多
关键词 photoionization cross sections energy levels wavelengths lifetimes
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Determination of Istanbul geoid using GNSS/levelling and valley cross levelling data
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作者 Müge Albayrak Mustafa TevfikÖzlüdemir +1 位作者 Mohammad Mohseni Aref Kerem Halicioglu 《Geodesy and Geodynamics》 2020年第3期163-173,共11页
The Istanbul GPS Triangulation Network(IGTN) and the Istanbul Levelling Network(ILN),established in2006,provide data for the determination of a local GNSS/levelling geoid model.These networks’ measurements were done ... The Istanbul GPS Triangulation Network(IGTN) and the Istanbul Levelling Network(ILN),established in2006,provide data for the determination of a local GNSS/levelling geoid model.These networks’ measurements were done separately on both the Asian and European sides of the Bosphorus Strait in the vicinity of Istanbul.To connect these regions for those networks,a Valley Cross Levelling(VCL) data set,acquired in 1986 and 2004,was used.The use of this VCL data set was challenging in calculating the Istanbul geoid model,primarily because of its errors.In this study,this challenge was overcome through newly collected VCL data in 2010,allowing for the readjustment of the ILN and the newly collected VCL data set.The Istanbul geoid model was computed using soft computing techniques including the adaptive-network-based fuzzy inference system(ANFIS) and the artificial neural networks(ANNs).The resulting Istanbul GNSS/levelling geoid model is shown to be more reliable when compared with the model computed using conventional interpolation techniques. 展开更多
关键词 GNSS/Icvclling GEOID Valley cross levelling Soft computing techniques Interpolation techniques
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Theoretical Analysis of Neutron Double-Differential Cross Sections of n +^9Be Reactions
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作者 段军锋 张竞上 +1 位作者 吴海城 孙小军 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第7期129-137,共9页
By using the nuclear reaction model for light nuclei, the calculations of the double-differential cross sections of outgoing neutrons from n +^9Be reactions are performed. The total outgoing neutrons are only come fr... By using the nuclear reaction model for light nuclei, the calculations of the double-differential cross sections of outgoing neutrons from n +^9Be reactions are performed. The total outgoing neutrons are only come from the (n, 2n)2a reaction channel. The (n, 2n)2a reaction channel is achieved through six different reaction approach, which are illustrated in this paper. The calculated results agree very well with the measured data at En = 7.1, 8.09, 8.17, 9.09, 9.97 and 10.26 MeV, because the updated level schemes related to the n + ^9Be reactions have been employed in this calculations. 展开更多
关键词 double-differential cross sections of total outgoing neutrons light nucleus reaction new levels
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