Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) has become an established part of neuroimaging and is used to diagnose and characterize several neurologic disorders. Intracerebral Haemorrhage (ICH) is a severe ...Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) has become an established part of neuroimaging and is used to diagnose and characterize several neurologic disorders. Intracerebral Haemorrhage (ICH) is a severe medical condition, which may develop quickly into a life-threatening situation, and thereby requires prompt medical attention. Early and reliable identification of the age of haemorrhage is essential when choosing the correct treatment, and estimating patient’s diagnosis and outcome. Diffusion Weighted (DW) images presents a variation in the image signal intensity characteristics relative to the different stages of ICH. In the present paper, an effort is made to document the variation in the image signal intensity characteristics of ICH at evolving stages, for 30 subjects, using High Frequency Power (HFP) parameter. Results showed that the difference in the HFP values on DW images for the subjects with ICH com- pared to their contralateral normal hemisphere, were highly significant (p 14 days). There was a negative correlation (r = ?0.81) observed between the RHFP values and the evolving stages of ICH. The results indicate that the quantitative changes in the RHFP values can be assessed to derive information about the stage of ICH, and their adoption in clinical diagnosis and treatment could be helpful and informative.展开更多
Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectra...Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power （0-6 kW） of ICPs （inductively coupled plasmas）. With the increase of net input power, the intensity of Hα im- proves rapidly （0-2 kW）, and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes： obvious increase （0-2 kW）, rapid increase （2-4 kW）, almost constant （4-6 kW）; while the intensities of Hγ increase very slowly. The energy levels of the excited hydro- gen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results.展开更多
电力系统中传统电压互感器存在体积大、对绝缘水平要求高等问题。针对上述问题,旨在研究一种新式的非接触式电压互感器,以降低电压互感器的绝缘设计难度、扩大电压互感器的使用场合等,其互感器设计采用基于电场耦合原理,设计单极式的结...电力系统中传统电压互感器存在体积大、对绝缘水平要求高等问题。针对上述问题,旨在研究一种新式的非接触式电压互感器,以降低电压互感器的绝缘设计难度、扩大电压互感器的使用场合等,其互感器设计采用基于电场耦合原理,设计单极式的结构解决了传统电压互感器由于接地极导致的绝缘设计难度大、成本高的问题;检测电路采用差动式的信号输入结构,有效抑制了共模干扰信号的影响;通过对互感器的建模仿真计算,优化了互感器电极的结构设计,实现了互感器的小型化,提高了互感器的分压比并有效减小了互感器测量的相位差。将电压互感器应用于单相10 k V电压等级下进行试验,试验结果表明,所设计的互感器可以满足对带电导体电压准确、实时的测量要求,能够为电力系统中防窃电及电网在线监测提供新的设计方法。展开更多
针对500kV变电站内500kV配电区域的工频电场强度普遍高于220kV配电区域和35kV配电区域、变电站工频电场强度超标点主要集中于500kV配电区域和220kV配电区域等状况,选取6座不同类型的500kV变电站进行500kV配电区域和220kV配电区域电磁场...针对500kV变电站内500kV配电区域的工频电场强度普遍高于220kV配电区域和35kV配电区域、变电站工频电场强度超标点主要集中于500kV配电区域和220kV配电区域等状况,选取6座不同类型的500kV变电站进行500kV配电区域和220kV配电区域电磁场强度检测,分析并总结出500kV变电站3种典型电气设备布置方式的工频电磁场强度分布特点。分析结果显示:敞开式布置和混合式气体绝缘金属封闭开关设备(hybrid gas insulated metal enclosed switchgear,HGIS)布置方式的工频电场强度明显高于气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)布置方式,说明户内GIS布置方式更能有效降低工频电场强度;3种布置方式的工频磁场强度差异并不显著,且均未出现超标现象。展开更多
文摘Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) has become an established part of neuroimaging and is used to diagnose and characterize several neurologic disorders. Intracerebral Haemorrhage (ICH) is a severe medical condition, which may develop quickly into a life-threatening situation, and thereby requires prompt medical attention. Early and reliable identification of the age of haemorrhage is essential when choosing the correct treatment, and estimating patient’s diagnosis and outcome. Diffusion Weighted (DW) images presents a variation in the image signal intensity characteristics relative to the different stages of ICH. In the present paper, an effort is made to document the variation in the image signal intensity characteristics of ICH at evolving stages, for 30 subjects, using High Frequency Power (HFP) parameter. Results showed that the difference in the HFP values on DW images for the subjects with ICH com- pared to their contralateral normal hemisphere, were highly significant (p 14 days). There was a negative correlation (r = ?0.81) observed between the RHFP values and the evolving stages of ICH. The results indicate that the quantitative changes in the RHFP values can be assessed to derive information about the stage of ICH, and their adoption in clinical diagnosis and treatment could be helpful and informative.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2011GB108011 and 2010GB103001)the Major International(Regional) Project Cooperation and Exchanges(No.11320101005)
文摘Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power （0-6 kW） of ICPs （inductively coupled plasmas）. With the increase of net input power, the intensity of Hα im- proves rapidly （0-2 kW）, and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes： obvious increase （0-2 kW）, rapid increase （2-4 kW）, almost constant （4-6 kW）; while the intensities of Hγ increase very slowly. The energy levels of the excited hydro- gen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results.
文摘电力系统中传统电压互感器存在体积大、对绝缘水平要求高等问题。针对上述问题,旨在研究一种新式的非接触式电压互感器,以降低电压互感器的绝缘设计难度、扩大电压互感器的使用场合等,其互感器设计采用基于电场耦合原理,设计单极式的结构解决了传统电压互感器由于接地极导致的绝缘设计难度大、成本高的问题;检测电路采用差动式的信号输入结构,有效抑制了共模干扰信号的影响;通过对互感器的建模仿真计算,优化了互感器电极的结构设计,实现了互感器的小型化,提高了互感器的分压比并有效减小了互感器测量的相位差。将电压互感器应用于单相10 k V电压等级下进行试验,试验结果表明,所设计的互感器可以满足对带电导体电压准确、实时的测量要求,能够为电力系统中防窃电及电网在线监测提供新的设计方法。
文摘针对500kV变电站内500kV配电区域的工频电场强度普遍高于220kV配电区域和35kV配电区域、变电站工频电场强度超标点主要集中于500kV配电区域和220kV配电区域等状况,选取6座不同类型的500kV变电站进行500kV配电区域和220kV配电区域电磁场强度检测,分析并总结出500kV变电站3种典型电气设备布置方式的工频电磁场强度分布特点。分析结果显示:敞开式布置和混合式气体绝缘金属封闭开关设备(hybrid gas insulated metal enclosed switchgear,HGIS)布置方式的工频电场强度明显高于气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)布置方式,说明户内GIS布置方式更能有效降低工频电场强度;3种布置方式的工频磁场强度差异并不显著,且均未出现超标现象。
