原子吸收分光光度法测定卤水中锶

研究了乙炔空气焰中,三强酸和25种阴、阳离子对测锶时的化学干扰和电离作用干扰。采用释放剂 La~(+3)3000微克/毫升,电离阻止剂 Na~+500微克/毫升,可消除或减小这些干扰。提出了三种测锶的方法,适于三种不同情况的卤水及其他天然水中分析锶。     

罗布泊红柳沙包落叶阳离子含量及环境指示意义

 红柳沙包沉积纹层是恢复古环境序列的一种新方法。通过对罗布泊地区红柳沙包沉积纹层中红柳落叶阳离子含量以及与环境变化关系研究表明：K+、Na+、Ca2+、Mg2+等4种阳离子平均含量分别为3.70 mg/g、40.33 mg/g、13.67 mg/g和8.08 mg/g,变化幅度排序为Ca2+ > K+ > Mg2+ > Na+。4种阳离子含量年际变化都较为明显,且变化规律较为一致,4种阳离子含量变化间的相关系数为0.653 0 ~ 0.813 8,表现为良好的正相关关系;各种阳离子与4种阳离子总量变化的相关系数为0.814 4 ~ 0.959 9,其中Na+含量与4种阳离子总量变化的相关系数最高,表明可以用Na+含量的变化或阳离子总量的变化分析变化趋势。阳离子含量与气温变化呈良好的正相关、与年降水量和湖水面积变化呈负相关;地下水水位降低、水质变差时,土壤水质也变差,阳离子含量增加;反之,地下水水位升高、水质变好时,土壤水质变好,阳离子含量降低。红柳落叶有机质阳离子含量的变化进一步验证了利用红柳沙包沉积纹层计年的可靠性和对罗布泊环境变化的可行性。     

海南岛尖峰岭地区山地土壤发生特性

对地处热带的海南岛尖峰岭地区的山地土壤的发生和发育特性进行了研究。因母岩因素以及较弱的成土作用和较强的侵蚀作用 ,土壤质地普遍较粗 ,石砾含量高。由于山地气候的垂直分异 ,不同海拔高度土壤间的发生特性存在较大差异。高海拔地区土壤易风化矿物含量高 ,低海拔地区土壤中抗风化能力强的锆石含量高 ;高海拔区土壤中粘土矿物以三水铝石和埃洛石为主 ,含有一定量的铝蛭石 ,低海拔土壤以高岭石为主 ,有一定量的水云母。伴随海拔高度的增加 ,阳离子交换量 (CEC7)、盐基总量、盐基饱和度、pH下降 ,而代换性酸H 、Al3 却逐渐增多。高海拔区湿润的水分状况和酸性成土环境导致粘粒的硅铝率、硅铁铝率较低海拔土壤小。尖峰岭地区土壤类型以雏形土为主 ,山麓分布有淋溶土。     

珠江磨刀门河口沉积物中主要离子含量及其分布

根据2003年夏季采集的37个磨刀门河口表层沉积物样品,对其中7种阴阳离子(K 、Na 、Ca2 、Mg2 、Cl-、HCO3-、SO42-)的含量及分布特征进行了分析,结果表明,阳离子和阴离子的最大值一般都出现在外海,呈现出由口内河床-拦门沙地区-外海逐渐增大的趋势;其次是拦门沙附近,阴阳离子的含量都普遍高于其他地区,阳离子互相之间具有良好的相关性,阳离子与Cl-以及SO42-这两种阴离子的相关性较好,此外,Cl-和SO42-这两种阴离子之间也具有较好的相关性,其影响因素主要是磨刀门河口的水体盐度、沉积物粒度、河口咸淡水混合作用、海洋动力作用和物质来源等。     

文摘及索引

(一)锂048.ISM—1离子筛阳离子交换剂的合成、结构和性质——Izv.Akad.Nauk.SSSR.,Neorg.Mater,1973.9(6),1041-6(俄文)曾以 MnO_2为基础进行对锂离子有高度选择性的 ISM—1离子筛阳离子交换剂的合成。这种阳离子交换剂是在 Li~ 存在下,利     

镁镍铝水滑石的合成及其在聚丙烯耐老化中的应用

采用沉淀法合成了镁镍铝水滑石 (MgNiAl-LDH),研究了不同尿素和水热温度对合成MgNiAl-LDH的影响。通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和扫描电镜（SEM）对MgNiAl-LDH进行了表征。将制得的MgNiAl-LDH添加至聚丙烯中（PP）中,制备MgNiAl-LDH/PP复合材料,通过加速老化及力学性能测试考察了MgNiAl-LDH的添加量对复合材料性能的影响。研究结果表明,当Mg2+:Ni2+:Al3+为2:1:1,反应温度为100℃、尿素用量为二价金属阳离子 (Mg2++Ni2+) 摩尔浓度的2.5倍时,合成结晶良好的MgNiAl-LDH。复合材料耐老化实验结果表明：当MgNiAl-LDH的填充量为6 wt%时,经加速老化后,MgNiAl-LDH/PP复合材料拉伸强度基本保持不变,抗老化性能明显。     

镁镍铝水滑石的合成及其在聚丙烯耐老化中的应用

采用沉淀法合成了镁镍铝水滑石(MgNiAl-LDH),研究了不同尿素和水热温度对合成MgNiAl-LDH的影响。通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和扫描电镜(SEM)对MgNiAl-LDH进行了表征。将制得的MgNiAl-LDH添加至聚丙烯中(PP)中,制备MgNiAl-LDH/PP复合材料,通过加速老化及力学性能测试考察了MgNiAl-LDH的添加量对复合材料性能的影响。研究结果表明,当Mg~(2+)∶Ni~(2+)∶Al~(3+)为2∶1∶1,反应温度为100℃、尿素用量为二价金属阳离子(Mg~(2+)+Ni~(2+))摩尔浓度的2.5倍时,合成结晶良好的MgNiAl-LDH。复合材料耐老化实验结果表明,当MgNiAl-LDH的填充量为6 wt%时,经加速老化后,MgNiAl-LDH/PP复合材料拉伸强度基本保持不变,抗老化性能明显。     

会仙喀斯特溶洞湿地、稻田和旱田土壤有机碳含量及其与养分的关系

以桂林会仙喀斯特溶洞湿地及其附近的稻田和旱田表层土壤为研究对象,采用常规方法,测定土壤有机碳和养分含量,并分析二者之间的关系。结果显示,喀斯特溶洞湿地的土壤有机碳含量为(21.77±1.42)g/kg,与稻田的土壤有机碳含量[(22.33±1.19)g/kg]没有显著差异,而旱田土壤有机碳含量为(12.78±0.22)g/kg,比湿地土壤低41.30%。稻田土壤的全氮含量、碱解氮含量、p H、阳离子交换量、交换性钙和交换性镁含量都与喀斯特溶洞湿地土壤无显著差异。但是,上述指标在旱田土壤中较低,降低幅度为15.63%~50.87%。统计结果表明,所有土壤全氮含量和p H与土壤有机碳含量都呈显著正相关(p0.01);土壤碱解氮、阳离子交换量、交换性钙和交换性镁与土壤有机碳含量都显著正相关(p0.05)。因此,土壤碱解氮、阳离子交换量、交换性钙和交换性镁对维持喀斯特溶洞湿地和稻田土壤较高的土壤有机碳水平具有重要的作用。     

贵州纳雍沙子岭煤矿M1煤层煤质特征分析

沙子岭煤矿位于贵州省纳雍县城以西,M1煤层属全区可采、较稳定煤层。经过对煤质资料的整理和分析,M1煤层以粉煤为主,沥青至玻璃光泽,粉煤呈粒状结构,参差状断口,煤层内生裂隙发育,宏观煤岩类型为暗—半亮型,属中灰分、中硫、低挥发分、中高发热量无烟煤,可用于动力用煤,民用煤。     

拉果错盐湖卤水蒸发机理的分子动力学模拟

采用分子动力学模拟,研究了西藏拉果错盐湖卤水中阴、阳离子以及水分子间的相互作用行为。以盐湖卤水等温蒸发过程中粒子浓度变化的四个阶段为研究对象,分别计算了不同体系的扩散系数、配位数、均方位移和径向分布函数。计算结果表明,液相浓度越低时,H2O分子对各离子之间的相互作用有抑制作用,液相中离子浓度越高时,SO42-易与CO32-竞争Li+形成离子对,从而影响盐湖卤水中Li+的富集。本文研究结果对盐湖卤水中Li+的迁移行为作出了机理解释,为盐湖卤水提锂的发展奠定了理论基础。     

A new theoretical treatment of compaction and the advective-diffusive processes in sediments: a reviewed basis for radiometric dating models

Classical treatment of mass conservation of solids in growing sediments states an advection-diffusion equation for the bulk sediment density. Thus, the diffusion coefficient has to account for elemental processes of exchange of solid particles by pore water or reciprocally. Nevertheless, in a gravity field, these exchanges are forced and cannot be treated as diffusion but as mass flow. A compaction potential energy is defined so that its spatial gradients force a mass flow involving a conductivity function. This leads to a more consistent definition of mass sedimentation rates and to a writing of the continuity equation for density involving only an advection term. Typical bulk density profiles show an asymptotic increase with depth. With the present formulation, this can be obtained as a steady-state solution under constant sedimentation rate and constant conductivity, while the classical formulation fails to do it. Alternatively, it can be found that under these conditions, the compaction potential is a linear function of the bulk density. The mass flow due to compaction and the compaction potential are found for several sediment cores from literature data. From this basis, the advection-diffusion equation for a particle-associated tracer is rewritten. In particular, when the mass flow term due to compaction is considered, the resulting sub-grid scale processes lead to a different formulation of the diffusive fluxes: they are proportional to the gradients of specific concentration in solids instead of the concentration per unit bulk volume. This new formulation is most suitable to find out analytical solutions for radiometric dating models involving mixing and compaction. Numerical solutions are found for the new and the classical treatment for some particular cases to illustrate differences.     

The Greening of Baltimore's Asphalt Schoolyards

Asphalt was becoming an integral part of the urban American landscape by the end of the nineteenth century. Not only was it emerging as the preferred alternative for street paving, its promoters were endorsing it for other purposes as well. Although Baltimore was not in the vanguard when it came to adopting asphalt for road surfaces, it soon followed the trend. Like other cities, it too found other applications for this versatile petroleum product, including the paving of playgrounds and schoolyards. Despite low maintenance costs, widespread use of asphalt as a recreational surface started to meet resistance in Baltimore during the 1960s. Fifty years later, stringent storm‐water runoff requirements are causing city officials to rethink how they deploy asphalt in an urban setting. In an effort to meet these new requirements, while at the same time improve recreational opportunities for school children, an alliance of government agencies, nonprofit organizations, and private developers has developed a strategy to remove asphalt from schoolyards—one that may serve as a model for other cities facing financial and sustainability challenges similar to those of Baltimore.     

Ray-mode duality for SH waves in earth models with crust and mantle discontinuities—II. The case of N discontinuities

Summary. In examining the effect of discontinuities in the Earth's interior on free oscillations, McNabb, Anderssen & Lapwood derived an equation for the asymptotic behaviour of torsional overtone eigenfrequencies of a discontinuous earth model, the constants in their equation being explicitly determined only for the case of one internal discontinuity. Since Brune's phase correlation method for the evaluation of eigenfrequencies from body-wave data implies a ray-mode duality only for continuous earth models, it is desirable to justify the McNabb et al. formulation from the point of view of ray theory.
By a novel method of ray analysis, Wang, Cleary & Anderssen showed that, for earth models with a single discontinuity between the Earth's surface and the core—mantle boundary, the McNabb et al. formulation can be derived from an adaptation of Brune's method to multiply reflected SH body waves recorded at small epicentral distances. In this paper, the technique of Wang et al. is extended to derive the McNabb et al. formulation (with constants explicitly determined) for the general case of earth models with N discontinuities. This establishes a basis for a ray-mode duality for discontinuous earth models.     

Temperature monitoring of the XPS board insulated subgrade along the newly constructed Gonghe-Yushu Highway in permafrost regions

On the basis of on-site measured data of the newly constructed Gonghe-Yushu Highway in a permafrost region, this paper analyzed thermal conditions of the subgrade with XPS insulated board according to different selected monitoring sections in various locations. We also summarized the geothermal distribution and change rules of subgrade with XPS insulation board under the asphalt pavement in summarized a high temperature frozen soil region. It is suggested that the shoulder of subgrade with XPS insulation board be widen to a reasonable width so as to keep the subgrade stable.     

Probabilistic analysis of embankment slope stability in frozen ground regions based on random finite element method

Prediction on the coupled thermal-hydraulic fields of embankment and cutting slopes is essential to the assessment on evolution of melting zone and natural permafrost table, which is usually a key factor for permafrost embankment designin frozen ground regions. The prediction may be further complicated due to the inherent uncertainties of materialproperties. Hence, stochastic analyses should be conducted. Firstly, Karhunen-Loeve expansion is applied to attain the random fields for hydraulic and thermal conductions. Next, the mixed-form modified Richards equation for mass transfer (i.e., mass equation) and the heat transport equation for heat transient flow in a variably saturated frozen soil are combined into one equation with temperature unknown. Furthermore, the finite element formulation for the coupled thermal-hydraulic fields is derived. Based on the random fields, the stochastic finite element analyses on stability of embankment are carried out. Numerical results show that stochastic analyses of embankment stability may provide a more rational picture for the distribution of factors of safety (FOS), which is definitely useful forembankment design in frozen ground regions.     

Extended formulation for Rayleigh-wave computations at high frequencies in a spherical layered earth

Summary. The earlier formulation of dispersion function, amplitude response and surface ellipticity for Rayleigh waves in a spherical layered earth has been extended by the reduced-delta matrix to avoid computational instability at high frequencies. We derive a modified formulation, where the layer thickness is kept separated during matrix multiplications. The present formulations are valid for an unlimited frequency range. A numerical experiment with single precision (six decimal digits accuracy) on an IBM 360/44 computer is performed at frequencies from 0.4 to 12.5 Hz on a Shield structure down to a depth of 1090 km below which a complete sphere is assumed. The experiment shows that both reduced-delta matrix and modified formulations generate roots of the dispersion equation without any reduction of layers. However, to avoid unnecessary computation, a layer-reduction procedure has been derived from a modified formulation when the contribution of deep layers becomes insignificant on surface waves.     

Three-dimensional numerical modelling of thermal transfer through the Vittel aquifer (Vosges, France), including approximated topographical effects

Summary. A geothermal and hydrochemical anomaly was observed in the Lower Triassic sandstone aquifer in the Vittel region (Vosges, France). This anomaly was attributed to a hydrothermal spring under sedimentary cover. In order to localize the hot spring and to quantify more precisely its flow rate and temperature, it is necessary to consider the 3-D thermal problem by taking into account the complex geometry of the domain and the flow rate in the aquifer. A 3-D numerical model of thermal conductive and forced convective transfer, developed for hydrological problems including approximate geometrical and topographical effects, is used which (i) can be directly applied to geologic strata (aquifers) with varying thickness and top and base slope; and (ii) allows calculation of heat flux anomalies associated with fluid flow in such geologically realistic aquifers.
The heat transfer equation is formulated in an orthogonal curvilinear coordinate system. As most geometries dealing with geothermal phenomena in sedimentary basins are nearly horizontal, this formulation can be simplified, leading readily to numerical solution with a finite difference method. The application of the 3-D model to the Vittel aquifer gives temperature results in agreement with measurements. These results provide evidence for the importance of associated forced convection and topographical effects for ground temperature distribution, and show clearly that heat flow in many basins is interpretable only if careful hydrological and thermal studies are made.     

劈窗算法中Planck方程展开式参数模型的拟合研究

地表温度是地球生态环境的重要指标,劈窗算法是目前利用遥感反演地表温度最为成熟的算法。为求解两个通道参数组成的热辐射方程组,需将Planck辐射方程线性展开以使各通道辐射值与亮温Ti直接相关,可通过引入中间参数Li与亮温Ti以不同的数学关系模型进行拟合。以MODIS数据源为例,对4种不同拟合关系进行分析比较,发现线性和幂函数模型具有较高的精度和稳定性,估计Li的误差范围为0.019~0.197。进一步分析这两个模型在地表温度反演中的误差及对参数的敏感性,结果显示幂函数模型在各种情况下都优于传统的线性模型劈窗算法。     

A stochastic modelling of earthquake frequencies

Summary. The frequency of earthquake occurrence in a given region can be formulated as

where n ( t ) is the number of earthquakes per unit time, and r, k and α are constants. Empirically determined values of α range from 0.67 to 1.0. This is a generalization of the modified Omori formula for aftershocks, the latter being an approximation of the former for n > k. This formula adequately describes the initial increasing and later decreasing activity of earthquakes during the Matsushiro and Wakayama swarms as well as aftershocks of large earthquakes.
When a random external force is added to this system as a driving mechanism, the equation above becomes

where v = l n ( n/k ) and R ( t ) is the random Gaussian noise. Repetitive seismic patterns with bursts, which are commonly observed in real earthquake sequences, are predicted from this formulation under stationary conditions. These formulations appear to be quite promising in helping to understand macroscopic features of the microearthquake activity.     

A new class of propagation models based on a factorization of the Helmholtz equation

Summary. A new class of propagation models, which is based on a factorization of the Helmholtz equation, that is, in principle, exact for range-independent environments, is presented. A numerical algorithm which makes use of the forward propagation feature of the propagation models and 'marches' the radiation field over a sequence of incremented range planes is derived and implemented. Numerical results of transmission loss as a function of range are obtained for a number of sample wave speed profiles for two members of the class of propagation models, one being an often-used parabolic wave theory and one being a high-frequency model that is new to our study. These results are compared to each other, to results obtained from an 'exact' numerical integration of the complete Helmholtz theory, and to results obtained using a WKB approximation to the Helmholtz equation formulation. The results demonstrate both the computational viability of the class of propagation models using the derived marching algorithm and very promising numerical agreement between the 'exact' results and those obtained using the high-frequency model.