Low-Frequency Plasma Waves in the Outer Polar CUSP: A Review of Observations from Prognoz 8, Interball 1, Magion 4, and Cluster

This paper presents a review of the most interesting observations of low-frequency plasma waves together with plasma particles which were made by the Interball 1, Magion 4 and Prognoz 8 satellites in the outer polar cusp. Accelerated plasma particles, hot electron populations and very strong wave activity, particularly at low frequencies, are observed. A detailed study of the wave spectra together with the distribution function for electrons indicate the correlation between the presence of lower-hybrid waves and the population of the particles with higher energy than in the surrounding space. These experimental facts suggest that strong coupling between waves and particles is responsible for plasma heating. During polar cusp crossings by Interball 1 and Prognoz 8, FFT analysis of the wave form indicates many bursts of ULF emissions in both electric and magnetic components. These waves have highly non-stationary characteristics. To study the dynamics of changes in the spectral characteristics of the waves wavelet analysis has been used. Nonlinear interactions are studied using bispectral methods of analysis. This presentation gives the results of such an analysis for selected cusp crossings at different altitudes. An example of wave activity registered by the STAFF instrument onboard the CLUSTER spacecraft in the polar cusp is also presented.     

电感耦合等离子体质谱法(ICP-MS)测定水系沉积物中的铌钽锆铪

建立电感耦合等离子体质谱法(ICP-MS)测定水系沉积物中铌、钽、锆、铪四种元素的分析方法。将样品与氢氧化钠、过氧化钠混合物放入高温炉中,熔融分解完全,用热水提取,过滤后弃去滤液,将滤纸及沉淀用酒石酸-盐酸溶液溶解,稀释至刻度测定。方法检出限(3s)为:LD(Nb)=0.08μg/g,LD(Ta)=0.04μg/g,LD(Zr)=0.5μg/g,LD(Hf)=0.04μg/g,精密度(RSD%,n=6)为:0.84%~4.21%。该测定方法具有灵敏度高、精密度好、分析速度快、线性范围宽、操作性强等优势。采用该方法对国家一级标准物质进行测定表明,其结果与标准值吻合。此方法已在实际地质调查样品分析中得到应用。     

An Investigation of Digestion Methods for Trace Elements in Bauxite and Their Determination in Ten Bauxite Reference Materials Using Inductively Coupled Plasma‐Mass Spectrometry

Trace elements from samples of bauxite deposits can provide useful information relevant to the exploration of the ore‐forming process. Sample digestion is a fundamental and critical stage in the process of geochemical analysis, which enables the acquisition of accurate trace element data by ICP‐MS. However, the conventional bomb digestion method with HF/HNO₃ results in a significant loss of rare earth elements (REEs) due to the formation of insoluble AlF₃ precipitates during the digestion of bauxite samples. In this study, the digestion capability of the following methods was investigated: (a) ‘Mg‐addition’ bomb digestion, (b) NH₄HF₂ open vessel digestion and (c) NH₄F open vessel digestion. ‘Mg‐addition’ bomb digestion can effectively suppress the formation of AlF₃ and simultaneously ensure the complete decomposition of resistant minerals in bauxite samples. The addition of MgO to the bauxite samples resulted in (Mg + Ca)/Al ratios ≥ 1. However, adding a large amount of MgO leads to significant blank contamination for some transition elements (V, Cr, Ni and Zn). The NH₄HF₂ or NH₄F open vessel digestion methods can also completely digest resistant minerals in bauxite samples in a short period of time (5 hr). Unlike conventional bomb digestion with HF/HNO₃, the white precipitates and the semi‐transparent gels present in the NH₄HF₂ and NH₄F digestion methods could be efficiently dissolved by evaporation with HClO₄. Based on these three optimised digestion methods, thirty‐seven trace elements including REEs in ten bauxite reference materials (RMs) were determined by ICP‐MS. The data obtained showed excellent inter‐method reproducibility (agreement within 5% for REEs). The relative standard deviation (% RSD) for most elements was < 6%. The concentrations of trace elements in the ten bauxite RMs showed agreement with the limited certified (Li, V, Cr, Cu, Zn, Ga, Sr, Zr and Pb) and information values (Co, Ba, Ce and Hf) available. New trace element data for the ten RMs are provided, some of which for the first time.     

Equations for transfer of radiation in plasma at decay interactions with ionacoustic waves

Equations for spectral energy densities of waves are obtained describing transfer of high frequency radiation through plasma without magnetic field at the decay of electromagnetic waves into electromagnetic and ionacoustic ones, as well as the decay of Langmuir waves into Langmuir and ionacoustic ones in case of isotropic distributions of all the above waves.     

浮游植物生物量研究 Ⅰ.浮游植物生物量细胞体积转化法

在海洋生态动力学研究过程中,采用浮游植物细胞数量来估算浮游植物丰度可以说是不够精确的,因为不同种的浮游植物细胞大小差别很大,只有浮游植物的生物量才能正确反映海洋生态系中的能量分布．本文以拟合浮游植物细胞相似体积方法,基于胶州湾生态动力学研究所获资料,计算了87种中国近海常见浮游植物的细胞体积、鲜重、碳含量、氮含量．     

地震期间电离层扰动现象研究

介绍了大量的关于地震电离层扰动现象研究的最新进展,研究表明地震发生前的几天或者几个小时电离层扰动被观测到,电离层前兆是确实存在.但要将震前的电离层扰动作为地震短临预报的工具,还有许多值得我们去深入研究和解决的问题.应用空间技术开展大区域范围内电离层参数的实时观测,如用地震电磁卫星、GPS台网、并和地面电离层垂测仪观测相结合,建立“电离层地震前兆监测系统”,无疑会加速这项研究的进程.     

丝阵Z箍缩早期消融等离子体动力学的二维数值模拟研究

采用理想磁流体力学模型,给出合理的二维(r, θ)质量注入边界条件,对丝阵Z箍缩早期消融等离子体的动力学过程进行了二维(r, θ)数值模拟研究,得到消融等离子体各参量以及磁场的二维时空分布.模拟结果表明,消融等离子体的运动包括四个主要阶段:首先向轴漂移,然后在轴线处滞止并形成先驱等离子体柱,随后先驱等离子体柱被压缩,最后缓慢膨胀.计算了不同丝阵半径和丝间距情况下消融等离子体到轴速度以及消融质量占丝阵总质量的份额,它们的变化规律与实验结果基本符合.通过     

行星际等离子区对火星探测器距离观测量的影响

根据Muhleman和Anderson在1981年给出的行星际空间等离子体密度模型,模拟计算了行星际等离子区对8GHz电波的距离延迟与太阳-地球-航天器夹角(SEP)和光路径长度(L)的关系。结果显示,在本文的模拟条件下,距离延迟随SEP和L从几毫米变化到几十米。最后,分别仿真了一条地火转移轨道和环火星轨道,计算了两种情况下行星际等离子区延迟对测站到航天器距离观测量的影响。     

微波等离子体炬原子发射光谱法测定铁和铝的研究

研究了低功率微波等离子体炬原子发射光谱法（ＭＰＴ－ＡＥＳ）对Ｆｅ，Ａｌ的测定。样品经气动雾化后，分别以流动注射与连续式两种方式引入ＭＰＴ。考察了用这两种进样方式时ＭＰＴ－ＡＥＳ的分析性能，证明低功率ＭＰＴ－ＡＥＳ具有良好的分析特性。     

Eolian deposition determined by the oxygen plasma furnace

The oxygen plasma furnace enables small samples of clastic sediment to be separated from filter papers at low temperatures without physical or chemical alteration of the sediment. This technique provides a suitable treatment for processing very small samples of alpine eolian sediment, enabling their grain size distribution, mineralogy, and origin to be determined.