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Experimental studies on ultralow frequency pulsed gradient magnetic field inducing apoptosis of cancer cell and inhibiting growth of cancer cell 被引量:1
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作者 曾繁清 郑从义 +6 位作者 张新晨 李宗山 李朝阳 王川婴 张新松 黄晓玲 张沪生 《Science China(Life Sciences)》 SCIE CAS 2002年第1期33-39,共8页
The morphology characteristics of cell apoptosis of the malignant tumour cells in magnetic field-treated mouse was observed for the first time. The apoptotic cancer cell contracted, became rounder and divorced from ad... The morphology characteristics of cell apoptosis of the malignant tumour cells in magnetic field-treated mouse was observed for the first time. The apoptotic cancer cell contracted, became rounder and divorced from adjacent cells; the heterochromatin condensed and coagulated together along the inner side of the nuclear membrane; the endoplasmic reticulums(ER) expanded and fused with the cellular membrane; many apoptotic bodies which were packed by the cellular membrane appeared and were devoured by some lymphocytes and plasma. Apoptosis of cancer cells was detected by terminal deoxynucleotidyl transferase mediated in situ nick end labeling(TUNEL). It was found that the number of apoptosis cancer cells of the sample treated by the magnetic field is more than that of the control sample. The growth of malignant tumour in mice was inhibited and the ability of immune cell to dissolve cancer cells was improved by ultralow frequency(ULF) pulsed gradient magnetic field; the nuclei DNA contents decreased, indicating that magnetic field can block DNA replication and inhibit mitosis of cancer cells. It was suggested that magnetic field could inhibit the metabolism of cancer cell, lower its malignancy, and restrain its rapid and heteromorphic growth. Since ULF pulsed gradient magnetic field can induce apoptosis of cancer cells and inhibit the growth of malignant tumour, it could be used as a new method to treat cancer. 展开更多
关键词 ULTRALOW frequency(ulf) pulsed gradient magnetic field cancer cell apoptosis inducing in situ NICK end labeling division inhibiting.
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岩石破裂过程中的超低频电磁异常 被引量:72
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作者 郝锦绮 钱书清 +2 位作者 高金田 周建国 朱涛 《地震学报》 CSCD 北大核心 2003年第1期102-111,共10页
震前电磁场和大地自电位的异常是重要的地震前兆现象.在零磁空间对超低频段的磁场和自电位的变化进行了岩石破裂的实验研究,细致地揭示出电场、磁场出现异常变化的全过程,对深入认识超低频电磁信号的微观机理具有重要的意义.实验发现,... 震前电磁场和大地自电位的异常是重要的地震前兆现象.在零磁空间对超低频段的磁场和自电位的变化进行了岩石破裂的实验研究,细致地揭示出电场、磁场出现异常变化的全过程,对深入认识超低频电磁信号的微观机理具有重要的意义.实验发现,岩石受力后应变、电位和磁场的缓慢变化在空间分布上是首先在近破裂源处出现,继而随裂纹的发展而改变位置;在时间序列上先出现自电位异常,然后是超低频磁场的变化;在异常形态上,超低频电磁信号呈现出早期、中期、晚期3个阶段的明显差异.研究表明,岩石微破裂引起裂隙尖端处的电荷分离. 静电荷在局部区域的积累和运移,导致了自电位的脉冲状变化;而在主破裂阶段,积累电荷的急速运动形成瞬间电流,激发了脉冲式的磁场异常.本文详细介绍了这一综合实验的技术步骤和观测结果,并对地震电磁前兆的微观机理进行了探讨. 展开更多
关键词 岩石破裂过程 地震前兆 电磁场 大地自电位 零磁空间 超低频 ulf
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MC-01超低铁芯磁探头的研制 被引量:8
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作者 耿胜利 赵庆安 《传感器世界》 2002年第4期13-15,共3页
为适应“大地电磁测深法”勘探石油和地热资源需要,在对加拿大MTC-60磁探头剖析基础上,研制出MC-01超低频铁芯磁探头,经室内外测试基本达到国外同期水平。本文重点介绍磁探头结构设计、工艺和测试结果。
关键词 电磁测探法 超低频 磁探头 铁芯 地质勘探
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10kV交联聚乙烯电缆绝缘老化超低频介损试验的研究 被引量:8
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作者 李宗辉 陈林艳 陈艺伟 《电气技术》 2020年第10期83-87,共5页
本文主要介绍超低频介损局放测试技术在10kV交联聚乙烯电缆的应用。根据国际电工委员会IEEE 400.2—2013屏蔽电缆超低频(小于1Hz)现场测试指南,对测试数据进行了分析,并对泉州地区19条老旧电缆进行超低频介损局放试验。结果显示,19个中... 本文主要介绍超低频介损局放测试技术在10kV交联聚乙烯电缆的应用。根据国际电工委员会IEEE 400.2—2013屏蔽电缆超低频(小于1Hz)现场测试指南,对测试数据进行了分析,并对泉州地区19条老旧电缆进行超低频介损局放试验。结果显示,19个中的6个电缆处于关注或者检修状态,部分电缆中发现水树枝。这些电缆如果继续投运,将极有可能发生故障导致停电。超低频介损测试可以有效评估交联聚乙烯电缆的绝缘老化状态,进而为配电检修提供指导,有助于提升配电网的安全性和可靠性。 展开更多
关键词 超低频介损 ccc电缆 水树 配电网
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Critical analysis of the ULF power depression as a possible Tohoku earthquake precursor
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作者 Vyacheslav A Pilipenko Valery A Martines-Bedenko +1 位作者 Akimasa Yoshikawa Kirolosse M Girgis 《Earthquake Science》 2024年第5期407-414,共8页
Among electromagnetic methods of short-term earthquake prediction,an approach is being actively developed based on the phenomenon of magnetic ultra-low-frequency(ULF)power depression occurring a few days before an ear... Among electromagnetic methods of short-term earthquake prediction,an approach is being actively developed based on the phenomenon of magnetic ultra-low-frequency(ULF)power depression occurring a few days before an earthquake.In particular,a nighttime geomagnetic power depression in the band 0.03-0.05 Hz was observed approximately 5 days before the catastrophic Tohoku 2011 earthquake.To verify the reliability of this method,we performed an extended analysis using data from magnetometer arrays JMA,MAGDAS,PWING,and INTERMAGNET.The selected stations included sites close to the epicenter(<300 km)and remote points(~10000 km).The band-integrated spectral power of nighttime magnetic noise decreased significantly from March 6-9,several days before the earthquake.However,such variations occur simultaneously not only at nearby stations but also at distant stations.During this event,the ULF power depression was caused by low global geomagnetic activity,as evidenced by the planetary index SME.Thus,the depression of geomagnetic ULF noise cannot be considered a reliable short-term precursor. 展开更多
关键词 earthquake forecast seismo-electromagnetic phenomena ultra-low frequency(ulf)pulsations
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Joint observations of the large-scale ULF wave activity from space to ground associated with the solar wind dynamic pressure enhancement
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作者 SUN XiaoYing HU YunPeng +3 位作者 ZHIMA Zeren DUAN SuPing LV FangXian SHEN XuHui 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第7期2215-2229,共15页
This study reports the rare ultralow-frequency(ULF) wave activity associated with the solar wind dynamic pressure enhancement that was successively observed by the GOES-17(Geostationary Operational Environmental Satel... This study reports the rare ultralow-frequency(ULF) wave activity associated with the solar wind dynamic pressure enhancement that was successively observed by the GOES-17(Geostationary Operational Environmental Satellite) in the magnetosphere, the CSES(China Seismo-Electromagnetic Satellite) in the ionosphere, and the THEMIS ground-based observatories(GBO) GAKO and EAGL in the Earth's polar region during the main phase of an intense storm on 4 November 2021. Along with the enhanced-pressure solar wind moving tailward, the geomagnetic field structure experienced a large-scale change. From dawn/dusk sides to midnight, the GAKO, EAGL, and GOES-17 sequentially observed the ULF waves in a frequency range of0.04–0.36 Hz at L shells of ~5.07, 6.29, and 5.67, respectively. CSES also observed the ULF wave event with the same frequency ranges at wide L-shells of 2.52–6.22 in the nightside ionosphere. The analysis results show that the ULF waves at ionospheric altitude were mixed toroidal-poloidal mode waves. Comparing the ULF waves observed in different regions, we infer that the nightside ULF waves were directly or indirectly excited by the solar wind dynamic pressure increase: in the area of L-shells~2.52–6.29, the magnetic field line resonances(FLRs) driven by the solar wind dynamic pressure increase is an essential excitation source;on the other hand, around L~3.29, the ULF waves can also be excited by the outward expansion of the plasmapause owing to the decrease of the magnetospheric convection, and in the region of L-shells ~5.19–6.29, the ULF waves are also likely excited by the ion cyclotron instabilities driven by the solar wind dynamic pressure increase. 展开更多
关键词 ultralow-frequency(ulf)wave solar wind dynamic pressure(P_(sw)) magnetic field line resonance(FLR) ion cyclotron instability
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基于小波分析的地磁甚低频脉动指数及其在高磁纬度地区甚低频脉动共轭对比研究中的应用
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作者 徐中华 CRobert Clauer +2 位作者 Michael DHartinger Hyomin Kim Daniel R Weimer 《极地研究》 CAS CSCD 北大核心 2024年第1期37-51,共15页
地磁甚低频脉动是甚低频磁流体波在磁层中传播的地面表现,开发近实时空间天气产品来监测这些地磁脉动至关重要。本文基于小波分析提出一种地磁甚低频脉动指数,并将其应用于研究在南极洲及西格陵兰岛的磁共轭位置观测到的地磁甚低频脉动... 地磁甚低频脉动是甚低频磁流体波在磁层中传播的地面表现,开发近实时空间天气产品来监测这些地磁脉动至关重要。本文基于小波分析提出一种地磁甚低频脉动指数,并将其应用于研究在南极洲及西格陵兰岛的磁共轭位置观测到的地磁甚低频脉动。研究结果表明,(1)该指数可有效识别Pc4—Pc5频率范围内的脉动事件(包括瞬态事件),并获得甚低频脉动在时域和频域的重要特征。(2)基于共轭位置地磁脉动的小波分析比较揭示了冬至日、夏至日条件下南北半球甚低频脉动的相似性和差异。本研究也表明,南北半球磁共轭位置观测到地磁脉动存在的差异受到行星际磁场条件、磁场拓扑、观测磁纬度和日照等条件影响,需要进一步研究案例中实际磁层和电离层配置以及驱动条件。 展开更多
关键词 地磁扰动 地磁甚低频脉动 地磁共轭
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Propagation of interplanetary shock excited ultra low frequency (ULF) waves in magnetosphere-ionosphere-atmosphere——Multi-spacecraft “Cluster” and ground-based magnetometer observations 被引量:3
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作者 WANG ChengRui1,2,ZONG QiuGang1,3 & WANG YongFu1 1 Institute of Space Physics and Applied Technology,Peking University,Beijing 100871,China 2 Sate Key Laboratory of Space Weather,Chinese Academy of Sciences,Beijing 100190,China 3 Center for Atmospheric Research,600 Suffolk Street,University of Massachusetts Lowell,MA 01854,USA 《Science China(Technological Sciences)》 SCIE EI CAS 2010年第9期2528-2534,共7页
The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward transmission.This paper quantitatively analyzes the propagation process of the ULF wave triggered by the i... The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward transmission.This paper quantitatively analyzes the propagation process of the ULF wave triggered by the interplanetary shock propagating from inner magnetosphere equatorial plane along magnetic field lines to the top of the ionosphere and below ionosphere propagating process and establishes a relatively complete magnetosphere-ionosphere-atmosphere propagation model which can be used to study the relationship between the amplitude of the ULF waves triggered by the interplanetary shock wave in magnetospheric space and the magnetic effect caused by the ULF waves.After a comparison with recent observations,we found that: in the event during November 7,2004 that an interplanetary shock wave interacted with the magnetosphere,Cluster satellites observed that electric field fluctuations and the band-pass filtered result of ground stations meridional component had similar characteristics.Comparing with the geomagnetic measurement near the footprints,we found that the electric field disturbance in the magnetosphere spread along the ground magnetic field lines in the form of the ULF waves and changed into geomagnetic disturbance.The result reveals that the ULF wave is in contact with the ground geomagnetic observation.The ULF waves couple with ionized components in ionosphere and spread to the ground in the form of electromagnetic waves.In this research,we believe that the magnetosphere,ionosphere and ground magnetic effects caused by interplanetary shock wave are the same physical phenomena responding in different locations.Based on the overall consideration of entire electromagnetic response to the interplanetary shock wave,we found that the correlation between CLUSTER multi-satellite observation and geomagnetic station observation is due to the ULF wave propagated in magnetosphere-ionosphere-atmosphere system,and we quantitatively interpreted this response process. 展开更多
关键词 ULTRA low frequency (ulf) wave magnetic storm IONOSPHERE IRI model INTERPLANETARY shock
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ULF electric and magnetic anomalies accompanying the cracking of rock sample 被引量:2
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作者 郝锦绮 钱书清 +2 位作者 高金田 周建国 朱涛 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第1期113-123,共11页
The anomalies of electric-magnetic field and self-potential before earthquakes are important precursory phenom-ena. A simulating experiment study on the variations in ultra-low frequency (ULF) magnetic field and self-... The anomalies of electric-magnetic field and self-potential before earthquakes are important precursory phenom-ena. A simulating experiment study on the variations in ultra-low frequency (ULF) magnetic field and self-poten-tial during rock cracking was carried out in a magnetic field-free space. The results revealing in detail the whole process of the occurrences of electric and magnetic anomalies are significant for understanding the microscopic mechanism of ULF electric and magnetic signals. The experiment indicated that at the initial stage the slow changes in strain, self-potential and magnetic field with small amounts appeared firstly near the source of initial cracking, and then extended as the crack developed on. In the time domain, the self-potential anomaly emerged first and ULF magnetic field changes arose then. The shape of the ULF electric and magnetic anomaly varied ob-viously in early-, mid- and late-term of the test. The authors attributed the pulse-like changes of self-potential to the generation and movement of the accumulated electric charges during the cracking caused by charge separation on the crack tips within the sample. While the magnetic pulses of shorter-period at the last stage of the test, may be induced by instantaneous electric current of the accumulated charge during the cracking acceleration. The technical method and the observational results of this experiment are given in detail and the microscopic mechanism of elec-tric and magnetic precursors before earthquake are discussed in the present paper as well. 展开更多
关键词 ultra-low frequency (ulf) SELF-POTENTIAL magnetic field rock cracking magnetic field-free space
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超低频振动传感器的设计与分析 被引量:2
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作者 张永喜 范云霄 《传感器世界》 2004年第7期26-29,共4页
本文提出了利用磁电式速度计实现超低频振动传感器的实用方法—通过串联式校正电路,在保持最佳阻尼的同时,使可测最低频率降至 0.5Hz 以下。同时,对该超低频振动传感 器的校正电路、工作原理 、传递函数以及校正前和校正后输出特性的... 本文提出了利用磁电式速度计实现超低频振动传感器的实用方法—通过串联式校正电路,在保持最佳阻尼的同时,使可测最低频率降至 0.5Hz 以下。同时,对该超低频振动传感 器的校正电路、工作原理 、传递函数以及校正前和校正后输出特性的差异进行了系统的分 析与阐述。 展开更多
关键词 传感器 超低频 振动 校正电路 传递函数
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DEMETER卫星观测的ULF电场波形干扰分析 被引量:1
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作者 欧阳新艳 申旭辉 《地震地磁观测与研究》 2015年第4期19-25,共7页
分析由法国DEMETER卫星观测的ULF电场波形数据,发现两种典型干扰:由标定信号引起的脉冲式周期干扰及详查期间噪声水平增加。结果表明:1周期干扰特征表现为:在固定工作模式期间,干扰以约4 min周期出现;在详查和巡查模式开始时刻,干扰出... 分析由法国DEMETER卫星观测的ULF电场波形数据,发现两种典型干扰:由标定信号引起的脉冲式周期干扰及详查期间噪声水平增加。结果表明:1周期干扰特征表现为:在固定工作模式期间,干扰以约4 min周期出现;在详查和巡查模式开始时刻,干扰出现。结合VLF频段功率谱,可确认此干扰由625 Hz标定信号引起;2在详查模式期间噪声增加,获取ULF频段功率谱发现,此干扰并非来自单个频点或频段信号,对空间真实的ULF扰动分析影响不大。认识ULF电场波形数据的典型干扰特征,可为后续ULF电场扰动研究提供参考,为我国电磁监测试验卫星同类数据干扰分析提供借鉴。 展开更多
关键词 DEMETER卫星 ulf电场波形 典型干扰 标定信号 详查模式
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高准确度的超低频交流电压表设计 被引量:1
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作者 何梓滨 《宇航计测技术》 CSCD 2011年第3期34-39,共6页
分析了超低频交流电压信号的测量方法,设计了基于采样计算方式的超低频交流电压测量方案。设计了以高速高精度A/D转换器和高性能DSP处理器为核心的超低频交流电压表硬件电路,设计了基于线性插值的非同步采样同步化算法,设计了基于复合... 分析了超低频交流电压信号的测量方法,设计了基于采样计算方式的超低频交流电压测量方案。设计了以高速高精度A/D转换器和高性能DSP处理器为核心的超低频交流电压表硬件电路,设计了基于线性插值的非同步采样同步化算法,设计了基于复合梯形求积公式的有效值算法。对所研制的超低频交流电压表进行了量值溯源与校准测试,测试结果表明所研制的超低频交流电压表测量频率下限达到了0.001Hz,测量不确定度优于0.01%。 展开更多
关键词 超低频 交流电压表 非同步采样 同步化算法 DSP
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超低频电压的测量 被引量:2
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作者 王荣 《微计算机信息》 2003年第8期45-45,共1页
提出了超低频电压的测量持点和方法。并介绍了一种精确测量超低频电压的原理电路。
关键词 超低频电压 测量 单片机 模拟测量 数字信号序列
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