泉州地磁台新址观测环境的监测与评估     

周锦屏  林子健 《地震地磁观测与研究》1994,15(6):5-11

本文对福建泉州地磁台白水营老址与丰州镇董埔村候选新台址，使用高灵敏度，快速记录的磁通门磁力仪，对台址周围观测环境进行了全面对比监测，从地磁短周期脉冲干扰，地磁场变化形态，日变幅、时均值相关分析等方面进行评估，指出老址的周围环境干扰量已超出０．１ｎＴ的＜＜地磁台站观测规范＞＞要求，新址符合＜＜地磁台站观测规范＞＞要求，适宜建立永久性地磁基本台。  相似文献   

崇明地震台FGE磁通门磁力仪D分量基线值的确定     

龚耀  赵俊香  朱培育  朱佳苗  秦俊高  黄永生 《地震地磁观测与研究》2005,(Z1)

基线值是考察记录仪运行是否稳定可靠的一个重要指标。本文以记录仪的D分量为例,通过认真仔细地分析与探索,使用数据处理的方法,解决了崇明台FGE磁通门磁力仪基线值不稳定的问题。这对基线值的确定和日常的数据处理都具有一定的指导意义。  相似文献   

High-field cantilever magnetometry as a tool for the determination of the magnetocrystalline anisotropy of single crystals   总被引：1，自引：0，他引：1  

Ftima Martín-Hernndez  Iris M. Bominaar-Silkens  Mark J. Dekkers  Jan Kees Maan 《Tectonophysics》2006,418(1-2):21

Cantilever torque magnetometry is utilized widely in physics and material science for the determination of magnetic properties of thin films and semiconductors. Here, we report on its first application in rock magnetism, namely the determination of K₁ and K₂ of single crystal octahedra of natural magnetite. The design of cantilever magnetometers allows optimization for the specific research question at hand. For the present study, a cantilever magnetometer was used that enables measurement of samples with a volume up to 64 mm³. It can be inserted into an electromagnet with a maximum field of 2 T. The cantilever spring is suitable for torque values ranging from 7.5 × 10^− 7 N·m to 5 × 10^− 6 N·m. The torque is detected capacitively; the measured capacitance is converted into torque by using a calibrated feedback coil. The magnetometer allows in-situ rotation of the sample in both directions and is, therefore, also suitable to analyze rotational hysteresis effects.The evaluation of the magnetite anisotropy constants involved Fourier analysis of the torque signal on the magnetite crystals' (001) and (110) planes. The absolute anisotropy constant has been computed using the extrapolation-to-infinite-field method. The value of K₁ at room temperature is determined at − 1.28 × 10⁴ [J m^− 3] (± 0.13, i.e. 10%) and that of K₂ at − 2.8 × 10³ [J m^− 3] (± 0.1, i.e. 2%). These values concur with earlier determinations that could not provide an instrumental error, in contrast with this work.The cantilever magnetometer performs four times faster than other torque magnetometers used for rock magnetic studies. This makes the instrument also suitable for magnetic fabric analysis.  相似文献   

Magnetic anisotropy of calcite at room-temperature     

Volkmar Schmidt  Detlef Günther  Ann M. Hirt 《Tectonophysics》2006,418(1-2):63

The intrinsic room temperature magnetic properties of pure calcite were determined from a series of natural crystals, and they were found to be highly dependent on the chemical composition. In general, dia-, para-, and ferromagnetic components contribute to the magnetic susceptibility and the anisotropy of magnetic susceptibility (AMS). With a combination of magnetic measurements and chemical analysis these three contributions were determined and related to their mineralogical sources. The intrinsic diamagnetic susceptibility of pure calcite is − 4.46 ± 0.16 × 10^− 9 m³/kg (− 12.09 ± 0.5 × 10^− 6 SI) and the susceptibility difference is 4.06 ± 0.03 × 10^− 10 m³/kg (1.10 ± 0.01 × 10^− 6 SI). These diamagnetic properties are easily dominated by other components. The paramagnetic contribution is due to paramagnetic ions in the crystal lattice that substitute for calcium; these are mainly iron and manganese. The measured paramagnetic susceptibility agrees with the values calculated from the known concentration of paramagnetic ions in the crystals according to the Curie law of paramagnetic susceptibility. Substituted iron leads to an increase in the AMS. The paramagnetic susceptibility difference was found to correlate linearly with the iron content for concentrations between 500 and 10,000 ppm. An empirical relation was determined: (k₁ − k₃)^para (kg/m³) = Fe-content (ppm) × (1 ± 0.1) × 10^− 12 (kg/m³/ppm). The maximum susceptibility difference (Δk = k₁ − k₃) was found to be unaffected by iron contents below 100 ppm. Ferromagnetic contributions due to inclusions of ferromagnetic minerals can dominate the susceptibility. They were detected by acquisition of isothermal remanent magnetization (IRM) and their contribution to the AMS was separated by high-field measurements.  相似文献   

低频数字电磁测深仪器系统及其在攀-西地区的应用          下载免费PDF全文

刘士杰  卢军 《地球物理学报》1989,32(4):417-422

本文介绍了在CTM-302型三分量磁通门磁力仪的基础上,研制的低频数字化大地电磁测深仪器系统;并根据该系统的功能和在攀-西地区的应用情况,对其发展前景进行了探索。  相似文献   

Polynomial smoothing of quiet-time magnetic variations for an irregularly spaced array of sites     

Michael L. Rossen  John F. Hermance 《Pure and Applied Geophysics》1987,125(1):41-65

Both magnetospheric and solid Earth geophysicists often employ two-dimensional arrays of recording variometers to reconstruct the spatial distribution of transient magnetic field variations at the Earth's surface. These discrete data are typically interpolated over a dense grid and the results, for example, are contoured. Few studies, however, have explored the efficacy of employing various polynomial forms for interpolating the same data set, nor have they examined how regional polynomial forms relate to magnetic variation sources on a global scale. The present study addresses some of these concerns. We quantify the characteristics of various smoothed models (i.e., low-order polynomial trend surfaces) for the same data set from a subglobal network of magnetic variometers. Using a relatively quiet interval of undisturbed diurnal variation, we characterize the spatial distribution of the three individual magnetic vector components at a single instant of time—or for what we call a ‘time slice’. We then explore how our model functions are affected by the presence or absence of various site data, i.e., what is the ‘information content’ of a particular site in our array and how important is it to constraining the final smooth model function that we derive? Finally, we explore how such local model functions are affected by including data from outside the array by studying the relation between our local polynomial forms and the global source fields from which they derive.  相似文献   

磁通门仪器室建设要点     

刘旭东  侯永骏 《东北地震研究》2002,18(3):39-41

地磁观测条件的特殊性决定了仪器观测室建设具有难度，本文介绍了大连地震台按照《地震及前兆数字指导规范（试行）》要求建设磁通门仪器室的过程及结果。  相似文献   

大连地震台GM3磁通门磁力仪的维护与应用     

侯永骏  于政轩 《华北地震科学》2002,20(4):47-50

“九五”地磁数字化改造项目仪器配置分为两个部分，绝对观测仪－CTM－磁力仪和相对记录仪－GM3磁通门磁力仪，大连台自仪器装备以来，经过精心安装调试与观测摸索出一套仪器维护与高精度观测的经验，资料精度逐步达到规范要求，2001年11月9日通过验收，被专家组评价为“达到国内领先水平”。  相似文献   

高温超导磁强计的研制及在TEM上的野外试验   总被引：3，自引：0，他引：3  

陈晓东  赵毅  王赤军  吕国印  李汝传  张杰 《地球学报》2002,23(2):179-182

文中介绍了高温超导磁强计的工作原理、特点、所研制的高温超导磁强计的性能指标以及在研制高温超导磁强计的过程中所解决的关键问题，定性地分析了高温超导磁哟计在瞬变电磁法（TEM）上应用的优势。在河北固安以高温超导磁强计做探头和使用传感应线圈做探头在瞬变电磁法（TEM）上进行了野外对比试验。试验结果表明，把高温超导磁强计应用于瞬变电磁法（TEM）上能够加大勘探深度。  相似文献   

地震电磁卫星载荷及现状          下载免费PDF全文

汤吉  赵国泽  陈小斌  詹艳  王继军  肖骑彬 《地球物理学进展》2007,22(3):679-686

系统介绍了法国DEMETER电磁卫星搭载的电场测量仪、磁场测量仪、离子分析仪和高能粒子探测仪的科学目的、简单的工作原理、观测模式以及观测的物理量.同时介绍了国际现有运行的地震电磁卫星搭载的观测仪器，对空间－地面电磁观测系统进行了简要的讨论.这些资料将为我国地震电磁卫星计划的实施提供参考.  相似文献