激光蒸汽云及其光源的探讨

激光显微光谱分析法目前在地质、冶金、国防等科学和技术领域里得到了广泛应用,它已成为物质微区化学成份分析的一种重要手段。要使激光显微光谱分析法能迅速的发展,必须解决当前分析上存在的标样的制     

Research Status and Progress of Balloon-borne Cloud and Precipitation Particles Probe

The accurate observation of the microphysical structure of cloud and precipitation plays an important role in understanding the formation of clouds and precipitation. In-situ measurement using measuring instruments carried by meteorological balloons is an effective way to obtain the microphysical properties of cloud and precipitation particles, which is a supplementary means for aircraft to observe cloud and precipitation particles. This observation method plays a more and more important role in in-situ measurement. According to the difference of the working principle of the existing balloon-borne cloud and precipitation particles probes, the detectors can be divided into particle impact-sampling sensors, particle imaging sensors, light-scattering sensors, light intensity attenuation sensors and charge measurement sensors. The working principles, key technologies and main advantages and disadvantages of typical instruments were summarized, and their applications to detailed cloud structure acquisition, cloud remote sensing method establishment, cloud and precipitation physical process research and parameterization, and scientific observation of thunderstorm clouds were briefly introduced. Finally, the development trend of balloon-borne cloud precipitation particle detectors was prospected, which will provide reference for related technical research and equipment development.     

Steroid geochemistry in the oxygen minimum zone of the eastern tropical North Pacific Ocean

Particulate matter was collected in the eastern tropical North Pacific Ocean, an area characterized by a shallow and intense oxygen minimum zone, in order to investigate the geochemistry of particulate organic matter in the ocean. Sinking, large particles and suspended, small particles were analyzed for sterols, 3-ketosteroids, 3-methoxy-steroids and sterenes. Vertical fluxes of steroid classes in sinking particles and concentrations of steroids in suspended particles decreased rapidly below the euphotic zone consistent with upper ocean sources and deep water decomposition. Significant compositional changes were observed with increasing depth and as a function of particle size. Sinking particles were enriched in C₂₇-Sterols but deficient in C₂₈ and C₂₉-sterols compared to the suspended particles. Suspended particles, especially in the oxygen minimum zone, were enriched in steroidal ketones and sterenes compared to sinking particles. Steroid distributions suggest that the oxygen minimum zone is the site of active “diagenetic” transformations, most likely microbially-mediated, of stenols to steroidal ketones, stanols and sterenes. These transformations occur preferentially in suspended particles relative to sinking particles.     

2013年1月京津唐地区霾事件气溶胶单颗粒形貌及硫酸盐化特征

2013年1月华北地区经历了重霾过程,为研究其污染特征,使用透射电子显微镜(TEM)及能谱(EDX)对北京、唐山和天津晴天和霾天气下气溶胶单颗粒基本形貌和硫酸盐化特征进行了分析。结果表明,华北地区气溶胶单颗粒包括矿物颗粒、硫酸盐颗粒、金属氧化物、烟尘集合体、有机颗粒和飞灰,仅在天津市样品中发现少量的Na Cl颗粒。对单颗粒的元素组成进行统计表明,华北地区晴天以富Si颗粒为主(31.0%),其次为富Ca颗粒(18.3%)、富Fe颗粒(14.1%)、富Cl颗粒(12.2%)等,霾天以富S颗粒为主(47.4%),其次为富Si颗粒(21.1%)和富Fe颗粒(13.4%)等。霾天气富Ca颗粒明显减少,同时在含S较高的颗粒中也含有Ca、K等元素,说明大气中含Ca、K等碱性矿物对雾水酸性有一定的缓冲作用。不同天气含S颗粒差异较大,霾天气明显高于晴天,S/Ca平均值在霾天明显较高,且大于0.8,说明在一定的SO2浓度下,大气湿度越大,硫酸盐化现象越明显,生成大量的硫酸铵盐。     

Structure of colloid particles in groundwaters on the territory of the Mayak production association and its impact on the colloid transport of radionuclides in subsoil environments

Colloid particles were examined in groundwaters sampled at the large contamination area of the subsoil environment at the Mayak production association in the Southern Urals. Colloid particles were separated from groundwater samples by ultrafiltration, and their composition and structure were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger spectroscopy (AS). Our results indicate that the chemical composition of the particles significantly varies at their surface and along their radii, from the peripheries to the cores of the particles. The data are used to estimate the possibility of utilizing properties of colloid particles contained in groundwaters (the composition, structure, and zeta potential of such particles) to numerically simulate the spreading of radioactive contamination with groundwaters with regard to the colloid mode of radionuclide transport. It is demonstrated that, along with transmitting electron spectroscopy (TEM) coupled with X-ray microprobe analysis and electron diffraction, the XPS and AS techniques make it possible to obtain information on heterogeneity in the distribution and modes of occurrence of various elements in colloid particles.     

隐伏金属矿床上升气流微粒特征、形成及迁移

结合地球化学和纳米科学技术的理论和研究方法,研究隐伏金属矿床有关微粒的形成、迁移和特征。对十多个金属矿床的研究表明,隐伏金属矿体地表沉积物中上升气流微粒样品有单个微粒和微粒聚合体,单个微粒形态有球状、近球状、不规则状、规则多边形、长柱状,微粒有晶质、非晶质和部分晶质。聚合体形态一般是不规则状、球状和近球状。它们的矿物成分主要有自然Au、自然Cu、氯化物、氧化物、硫酸盐、氢氧化物等。成矿元素Au、Cu可以自然金属或自然合金形式存在,Cu、Pb、Zn等成矿元素可以氧化物或硫酸盐等形式存在,也可以存在于氧化物、氢氧化物、氯化物、硫酸盐等微粒中作为杂质元素,这些是隐伏金属矿体的指示微粒。成矿期后,与隐伏金属矿体有关微粒主要形成于断层作用、氧化作用和生物作用。在上升气流中,微粒呈“布朗运动”。     

云理论在资源环境领域中的应用前景展望

由中国科学家李德毅提出的隶属云概念是对模糊隶属度的发展,目前已经发展成为由云模型、云变换、云推理等组成的“云计算”理论与方法体系,其在地学界的应用尚未开展起来。模糊隶属云现象在资源环境领域普遍存在,例如环境污染等级的模糊评判、综合物化探异常含矿性的模糊识别、矿山安全评价、描述性地学数据的定量化处理、地学数据仓库的知识挖掘、地理信息系统中属性数据的不确定性处理、矿产资源评价预测等,迫切要求形成一系列数学假设和处理方法均符合多重模糊属性的处理方法。云计算理论与方法满足了这种客观需要,在地学信息处理方面具有十分广泛的应用前景。     

隐伏矿床上方纳米铜颗粒存在形式与成因

在铜镍矿床覆盖层土壤颗粒中和其下伏原生矿石中同时采集到金属纳米颗粒,颗粒在其粒径大小、形貌、连接和簇聚形式、微粒元素组合等性质上相似,表明两者为同成因物质,是内生成矿作用元素存在形式,土壤颗粒中金属纳米颗粒来自深部矿体。在金矿上方土壤颗粒中采集的纳米金属颗粒,与在铜镍矿床覆盖层土壤颗粒中采集观测到的微粒,在微粒性质可以对比,表明元素的纳米微粒是稳定形式,在其源区形成后可借助多种营力,穿越后期地质作用覆盖层,在近地表被土壤地球化学障捕获滞留,是深部矿化的有效传递物质。深穿透地球化学技术可从土壤中分离富集采集到此纳米微粒,并通过其微粒性质,追踪其源区性质。此研究结果在实用意义上,可为以土壤作为采样介质的深穿透地球化学勘查探测覆盖区隐伏矿方法提供理论依据。     

The influence of humic materials on the flotation of coal

The effect of humic material on the flotation response of coal has been examined. The results show that while hydrogen ions do not adversely affect the flotation of coal particles, they interact with humic material adsorbed on the surface of the clay particles and render their surfaces oleophilic. This behaviour enables the clay particles to adsorb collector in preference to the coal particles and thus inhibit coal flotation.     

Geochemical and morphological characteristics of gold particles from recent river deposits and the fossil placers of the Witwatersrand

A relationship has been established between morphological features and fineness of gold particles and the distance over which they have been transported in recent alluvial placer deposits, such as the rivers of the Barberton Mountain Land, South Africa and the river Rhine in Germany. It was possible to show that most gold particles from the Witwatersrand conglomerates retained their detrital morphology and by comparing them with particles from recent alluvial gold deposits it was possible to estimate the distance of transport for the Witwatersrand gold, which in most cases ranged from 10 km to 30 km. Gold particles in recent placers show a characteristic increase in fineness with increasing distance of transport because of the leaching of the silver from them. The Witwatersrand gold particles on the other hand, have retained their primary fineness, because leaching of silver in the oxygen-deficient Precambrian atmosphere was not feasible chemically.     

黄河内蒙古段上覆水、悬浮物和底泥重金属特征及生态风险研究

系统地采集黄河内蒙古段上覆水、悬浮物和底泥样品,分析其中重金属元素的含量。采用地质累积指数法和潜在生态危害系数法,研究了黄河干流内蒙古段的上覆水、悬浮物和底泥的重金属沿程分布特征、污染程度和生态风险。分析结果显示:除了As元素,悬浮物中重金属元素含量总体上高于底泥中的含量。地质累积指数法评价结果表明:悬浮物和底泥属于无污染—中度污染,悬浮物总体上比底泥污染严重;潜在生态危害系数法评价结果表明:底泥和悬浮物中重金属的生态危害总体上属轻微状态;因此,生态风险指数法和地质累积指数评价结果基本一致。     

悬浮颗粒形状对其在多孔介质中迁移和沉积特性的影响

悬浮颗粒在多孔介质中迁移的研究在地下水回灌、地下污染物扩散、核废料处置、石油开采等领域有重要的理论意义和应用价值。为了研究形状对颗粒迁移的影响,对1组球状颗粒（10 ?m中位粒径）和2组杆状颗粒（长径比为3:1和6:1）进行了三阶段室内土柱试验,得到了不同形状颗粒在多种溶液离子强度条件下的穿透曲线。结合DLVO理论分析了悬浮颗粒沉积和释放机制,阐释了形状对颗粒迁移行为的影响。试验结果表明,颗粒形状对迁移特性有重要影响,当离子强度较低时（6 mmol/L）,DLVO势能曲线展现较高能量壁垒,各种形状颗粒沉积主要为次级势阱沉积;当离子强度较高时（150 mmol/L）,球状颗粒因能量壁垒较高,其滞留机制仍以次级势阱沉积为主,但长径比为6:1的杆状颗粒在次级势阱和初级势阱都有沉积,这和杆状颗粒的静电性能和优先方向有关。对于杆状颗粒,边位沉积比端位沉积具有更深的次级势阱和更大的影响距离,边位沉积是更加稳定的沉积方式和沉积的优先方向。基于Derjaguin近似方法的DLVO理论计算显示,DLVO理论预测结果和土柱试验结果吻合较好。     

Erosion of bentonite particles at the interface of a compacted bentonite and a fractured granite

Compacted bentonite has been considered as a candidate buffer material in the underground repository for the disposal of high-level radioactive waste. An erosion of bentonite particles caused by a groundwater flow at the interface of a compacted bentonite and a fractured granite was studied experimentally under various geochemical conditions. The experimental results showed that bentonite particles could be eroded from a compacted bentonite buffer by a flowing groundwater depending upon the contact time, the flow rate of the groundwater, and the geochemical parameters of the groundwater such as the pH and ionic strength.

A gel formation of the bentonite was observed to be a dominant process in the erosion of bentonite particles although an intrusion of bentonite into a rock fracture also contributed to the erosion. The concentration of the eroded bentonite particles eroded by a flowing groundwater was increased with an increasing flow rate of the groundwater. It was observed from the experiments that the erosion of the bentonite particles was considerably affected by the ionic strength of a groundwater although the effect of the pH was not great within the studied pH range from 7 to 10. An erosion of the bentonite particles in a natural groundwater was also observed to be considerable and the eroded bentonite particles are expected to be stable at the given groundwater condition.

The erosion of the bentonite particles by a flowing groundwater did not significantly reduce the physical stability and thus the performance of a compacted bentonite buffer. However, it is expected that an erosion of the bentonite particles due to a groundwater flow will generate bentonite particles in a given groundwater condition, which can serve as a source of the colloids facilitating radionuclide migration through rock fractures.     

Effect of suspension and sedimentation on the amount of microbial colonization of salt marsh microdetritus

The relative density of bacterial colonization of small (5 to 40 μ diameter) suspended and sedimented detritus particles in salt marsh creeks was studied using an europium chelate-fluorescent brightener stain coupled with epifluorescent microscopy. Particles were obtained from four substations at each of three sites in salt marshes bordering the York River, Virginia. Coverage of detrital particles by bacteria was uniformly low, averaging 1.54%±1.83% of the particle surface area. Suspended particles larger than 10 μ diameter had lower bacterial densities than did sedimented particles in the same size ranges. It is speculated that microbial growth may be enhanced on sedimented particles both through lack of motion and access to greater nutrient concentrations.     

Comprehensive Stability Evaluation of Rock Slope Using the Cloud Model-Based Approach

This article presents the cloud model-based approach for comprehensive stability evaluation of complicated rock slopes of hydroelectric stations in mountainous area. This approach is based on membership cloud models which can account for randomness and fuzziness in slope stability evaluation. The slope stability is affected by various factors and each of which is ranked into five grades. The ranking factors are sorted into four categories. The ranking system of slope stability is introduced and then the membership cloud models are applied to analyze each ranking factor for generating cloud memberships. Afterwards, the obtained cloud memberships are synthesized with the factor weights given by experts for comprehensive stability evaluation of rock slopes. The proposed approach is used for the stability evaluation of the left abutment slope in Jinping 1 Hydropower Station. It is shown that the cloud model-based strategy can well consider the effects of each ranking factor and therefore is feasible and reliable for comprehensive stability evaluation of rock slopes.     

大气颗粒物矿物相组成与微观形貌研究进展

矿物颗粒是大气颗粒物的重要组成部分,其物相组成和微观形貌等特征既对人体危害的机理研究具有重要意义,同时蕴藏着颗粒物来源及变化等有用信息。自上个世纪80年代至今,大气颗粒物中矿物颗粒物相组成及微观形貌的研究大致经历了3个阶段,主要体现在研究方法和手段的不断探索与进步,研究对象由总悬浮颗粒向PM_2.5甚至更细颗粒物以及由全颗粒分析向单颗粒分析转移,不断重视原生矿物变化及次生矿物生成机理研究。本文提出发生硫化现象的原生矿物及二次成因硫酸盐颗粒是未来研究的重要方向之一。     

Changes in concentration and size distribution of aerosols during fog over the south Indian Ocean

Measurements of the concentration and size distribution of aerosol particles in the size-ranges of 0.5–20 μm and 16–700 nm diameters were made during six fog episodes over the south Indian Ocean. Observations show that concentrations of particles of all sizes start decreasing 1–2 hours before the occurrence of fog. This decrease is more prominent for coarse particles of >1 μm diameter and continues until 10–20 minutes before the onset of fog when particle concentrations in all size ranges rapidly increase by one/two orders of magnitude in ∼20 minutes. Thereafter, concentrations of particles of all sizes gradually decrease until the dissipation of fog. After the fog dissipation, concentrations of coarse mode particles rapidly increase and restore to their pre-fog levels but concentrations of the Aitken mode particles decrease slowly and reach their pre-fog levels only after 1–2 hours. The net effect of fog is to change the bimodal size distributions of aerosols with a coarse mode at 1.0 μm and an accumulation mode at 40–60 nm to a power law size distribution. It is proposed that the preferential growth and sedimentation of the coarse mode hygroscopic particles in the initial phase cause a large decrease in the aerosol surface area. As a result, the low vapour pressure gases which were initially being used for the growth of coarse mode particles, now accelerate the growth rates of the accumulation and Aitken mode particles.     

Characterization of sinking particles from the northwest Mediterranean Sea using advanced solid-state NMR

Sinking particles are the major transporter of organic carbon from surface to the deep ocean, and their chemical composition changes dramatically with depth. However, the exact mechanism controlling the chemical transformation as particles sink is not well understood, and little detail is known about the structural changes. This is mainly due to the paucity of techniques available to analyze the major macromolecular components of sinking particles. Here we applied advanced solid-state NMR techniques, including cross polarization/magic angle spinning (CPMAS), direct polarization/magic angle spinning (DPMAS), two-dimensional ¹H-¹³C heteronuclear correlation (2D HETCOR) and ¹H T₁ inversion recovery, on sinking particles collected in the northwest Mediterranean Sea. The CPMAS ¹³C NMR spectrum of the 200-m particles is significantly different from that of the DPMAS ¹³C NMR spectrum: CPMAS overestimates the NCH and CHO groups, but underestimates the aliphatic components, which is attributed to the high mobility of polymethylene units. Thus DPMAS is more suitable for quantifying organic composition of sinking particles. Using 2D HETCOR with ¹H spin diffusion, we estimated that the size of domains (similar structural entities either physically or chemically grouped together) in the 200-m sinking particles can be as large as tens of nanometers. The results of CPMAS ¹³C NMR and ¹H inversion recovery on sinking particles from 200, 520 and 920 m indicate that the macromolecular heterogeneity observed in surface particles virtually disappears as particles sink into the deep ocean. This suggests that the macromolecular components at depth are different in structural composition than those in surface waters, and may be compositionally homogenized as particles sink.     

Vortex motions and transportation of fine disperse dust particles in the ionosphere

Redistribution of dust particles in the ionosphere as a result of vortical motions is discussed. The following possibilities are studied: capture and evolution of dust particles in acoustic-gravitational (AG) vortices, formation of dust vortices as a result of involving a great number of dust particles into vortex motions, and formation of vertical dust flows (streamers). It is shown that excitation of AG-vortices at altitudes of 110–130 km as a result of development of AG-wave instability, associated with non-zero balance of heat fluxes, owing to solar radiation, water vapors condensation, infrared emission of the atmosphere, and thermal conductivity, leads to a substantial transportation of dust particles and their mixing at altitudes of 110–120 km. Layers of dust particles in the ionosphere with a thickness of about a kilometer, forming at altitudes less than 120 km, distribute within the region of existence of AG-vortical structures. As a result, at altitudes of 110–120 km, dust vortices can appear, and transportation of particles up to altitudes of 130 km becomes possible. One of the ways of transportation of dust particles in the ionosphere is vertical flows (streamers), which are generated by dust vortices as a result of development of parametric instability.     

Unmelted meteoritic debris in the Late Pliocene iridium anomaly: Evidence for the ocean impact of a nonchondritic asteroid

Ir-bearing particles have been recovered from 2 piston cores in the Antarctic Basin in the southeastern Pacific. In core E13-3 the particles closely correspond to the Late Pliocene Ir anomaly and have a fluence of ~100 mg cm^?2. In core E13-4, 120 km to the southwest, the particle fluence is ~4 mg/cm^?2. Particles with diameters from 0.5 to 4 mm contain at least 35% of the Ir in this horizon. Three types of particles have been identified: 1) vesicular, 2) basaltic, and 3) metal. The vesicular particles appear to be shock-melted debris derived from the oceanic impact of a howarditic asteroid containing a minor metal component. These particles have recrystallized from a melt and impact into the ocean has resulted in the incorporation of Na, K, Cl, and radiogenic Sr from the ocean water target. The basaltic clasts appear to be unmelted fragments of the original asteroid which may have separated from the main body prior to impact. Combined vesicular and basaltic particles are believed to have formed by collisions in the debris cloud. Estimates of the diameter of the projectile range from 100 to 500 m. By many orders of magnitude this is the most massive achondrite sampled by a single meteorite fall.