Copper partitioning between granitic silicate melt and coexisting aqueous fluid at 850 °C and 100 MPa

Experiments on the partitioning of Cu between different granitic silicate melts and the respective coexisting aqueous fluids have been performed under conditions of 850 °C, 100 MPa and oxygen fugacity（f O₂） buffered at approaching Ni–Ni O（NNO）. Partition coefficients of Cu（DCu= cfluid/cmelt） were varied with different alumina/alkali mole ratios [Al₂O₃/（Na₂O·K₂O）, abbreviated as Al/Alk], Na/K mole ratios, and Si O₂ mole contents. The DCu increased from 1.28 ± 0.01 to 22.18 ± 0.22 with the increase of Al/Alk mole ratios（ranging from 0.64 to 1.20）and Na/K mole ratios（ranging from 0.58 to 2.56）. The experimental results also showed that DCuwas positively correlated with the HCl concentration of the starting fluid.The DCuwas independent of the Si O₂ mole content in the range of Si O₂ content considered. No DCuvalue was less than 1 in our experiments at 850 °C and 100 MPa, indicating that Cu preferred to enter the fluid phase rather than the coexisting melt phase under most conditions in the melt-fluid system, and thus a significant amount of Cu could be transported in the fluid phase in the magmatichydrothermal environment. The results indicated that Cu favored partitioning into the aqueous fluid rather than themelt phase if there was a high Na/K ratio, Na-rich, peraluminous granitic melt coexisting with the high Cl-fluid.     

Geo-engineered buffer capacity of two-layered absorbing system under the impact of rock avalanches based on Discrete Element Method

Many rock avalanches were triggered by the Wenchuan earthquake on May 12, 2008 in southwest China. Protection galleries covered with a single soil layer are usually used to protect against rockfall. Since one-layer protection galleries do not have sufficient buffer capacity, a two-layered absorbing system has been designed. This study aims to find whether an expanded poly-styrol (EPS) cushion, which is used in the soil-covered protection galleries for shock absorption, could be positioned under dynamic loadings. The dynamic impacts of the two-layered absorbing system under the conditions of rock avalanches are numerically simulated through a 2D discrete element method. By selecting reasonable parameters, a series of numerical experiments were conducted to find the best combination for the two-layered absorbing system. The values of the EPS layer area as a percentage of the total area were set as 0% (S₁), 22% (S₂), and 70% (S₃). 22% of the area of the EPS layer was found to be a reasonable value, and experiments were conducted to find the best position of the EPS layer in the two-layered absorbing system. The numerical results yield useful conclusions regarding the interaction between the impacting avalanches and the two-layered absorbing system. The soil layer can absorb the shock energy effectively and S₂ (0.4-m thick EPS cushion covered with soil layer) is the most efficient combination, which can reduce the impact force, compared with the other combinations.     

The measurement and model construction of complex permittivity of vegetation

The complex permittivity of targeted objects is an important factor that influences its microwave radiation and scattering characteristics. In the quantitative research of microwave remote sensing, the study of the dielectric properties of the vegetation to establish the relationship between its specific physical parameters and complex permittivity is fundamental. In this study, six categories of vegetation samples were collected at the city of Zhangye, a key research area of the Heihe watershed allied telemetry experimental research. The vector network analyzer E8362B was used to measure the complex permittivity of these samples from 0.2 to 20 GHz by the coaxial probe technique. The research focused mainly on the corn leaves, and an empirical model was established between the gravimetric moisture and the real/imaginary parts of complex permittivity at the main frequency points of microwave sensors. Furthermore, the empirical model and the classical Debye-Cole model were compared and verified by the measured data collected from the Huailai County of Hebei Province. The results show that the newly-established empirical model is more accurate and more practical as compared to the traditional Debye-Cole model.     

Influence of ground motion spatial variation,site condition and SSI on the required separation distances of bridge structures to avoid seismic pounding

It is commonly understood that earthquake ground excitations at multiple supports of large dimensional structures are not the same. These ground motion spatial variations may significantly influence the structural responses. Similarly, the interaction between the foundation and the surrounding soil during earthquake shaking also affects the dynamic response of the structure. Most previous studies on ground motion spatial variation effects on structural responses neglected soil–structure interaction (SSI) effect. This paper studies the combined effects of ground motion spatial variation, local site amplification and SSI on bridge responses, and estimates the required separation distances that modular expansion joints must provide to avoid seismic pounding. It is an extension of a previous study (Earthquake Engng Struct. Dyn. 2010; 39 (3):303–323), in which combined ground motion spatial variation and local site amplification effects on bridge responses were investigated. The present paper focuses on the simultaneous effect of SSI and ground motion spatial variation on structural responses. The soil surrounding the pile foundation is modelled by frequency‐dependent springs and dashpots in the horizontal and rotational directions. The peak structural responses are estimated by using the standard random vibration method. The minimum total gap between two adjacent bridge decks or between bridge deck and adjacent abutment to prevent seismic pounding is estimated. Numerical results show that SSI significantly affects the structural responses, and cannot be neglected. Copyright © 2010 John Wiley & Sons, Ltd.     

Metallogeny and environmental impact of Hg in Zn deposits in China

Zinc smelting is currently regarded as one of the most important atmospheric Hg emission sources in the world. In order to assess the potential environmental impacts of Hg from Zn smelting in China, the distribution of total Hg concentration (HgT) in Zn concentrates (ZCs) from 100 Zn deposits in China was investigated. It was found that HgT varies depending on the ore types and their geneses. Zinc concentrates from sedimentary-exhalative deposits (SEDEX, geometric mean = 48.2 μg/g) have the highest HgT. The possible explanation is that the sources of mineralizing solutions for SEDEX deposits are deep formational brines in contact with sedimentary rocks, and there are much higher background Hg contents in sedimentary rocks. Zinc concentrates from volcanic hosted massive sulfide deposits (VMS, geometric mean = 11.5 μg/g) and Mississippi Valley-Type (MVT, geometric mean = 10.1 μg/g) deposits have intermediate HgT. VMS may receive most of their Hg from fluid–rock interaction and/or by direct input of gaseous Hg from a mantle source. However, the source of metals within MVTs may be the low-temperature hydrothermal solution formed by diagenetic recrystallization of the carbonates. Intrusion related deposits (IRs) have the lowest HgT (Geomean = 2.4 μg/g), and the dispersion of Hg in the IRs seems to be influenced by the temperature of ore formation and/or the nature of wall–rock alteration. Finally, it was estimated that the annual Hg emission to the atmosphere from Zn smelting in China was about 107.7 tons in 2006.     

SCISSORS DIFFERENCE AND ITS IMPACTS ON ECONOMIC VALUE OF CULTIVATED LAND IN CHINA

1IN T R O D U C T IO NAs we allknow,China isa countrywith vastpopulationand scarcelandpercapita(Y ANG and LI,2000)."T rea-suringlandverymuch,utilizinlgandrationallaynd pro-tectingthe cultivatedland conscientiously"is funda-mental statepolicyofChina.At the…     

四川省水土资源开发利用现状特征、问题及可持续利用对策

系统分析评价研究了2004年四川水土资源开发利用现状特征及其存在的主要问题，针对四川人地矛盾日趋尖锐、水土流失严重、水资源利用率低、水资源污染仍较严重尤其饮用水源地水质堪忧等制约全省经济社会可持续发展的重要因素，提出了实现四川水土资源可持续利用的对策和措施。     

高光谱遥感仪器的光谱参数和信噪比需求

卫星短波红外CO₂遥感获得大气低层CO₂浓度信息,已成为目前国际热点研究领域。结合气候变化及碳源、汇观测需求,利用高精度大气辐射传输模式研究了高光谱分辨率、高精度CO₂探测目标的可实现性。针对高光谱CO₂探测器光栅分光、阵列探测器特点,分析了光谱分辨率、光谱采样率等关键技术指标对CO₂探测的可能影响;基于辐射敏感度因子分析了不同探测精度要求下的信噪比需求。结果表明:高光谱CO₂探测器首先应具有足够高的光谱分辨率,以便从太阳反射连续谱段中分辨出CO₂吸收线;为保证CO₂光谱的准确性,光谱仪所用探测器面元应该保证光谱采样率大于2;尽管探测边界层内CO₂浓度1%变化所要求的信噪比难以达到,但探测整层大气CO₂浓度1%的变化所需要的信噪比是可以实现的。     

MicrotopsⅡ型太阳光度计的使用、计算及定标

通过研究文献和在使用仪器过程中积累的一些经验,介绍MicrotopsⅡ型5通道手持式太阳光度计的特征、仪器使用前的参数设置、使用中应该注意的问题以及大气气溶胶光学厚度(AOD)的计算原理和仪器定标方法,以便为仪器的使用者提供借鉴。对广州热带海洋气象研究所2004年9月19日在国家南岭森林公园的一次对比试验观测数据进行分析,结果显示,两台仪器大气气溶胶光学厚度值非常接近,500 nm通道的AOD值相差小于0.01,说明两台仪器的厂家定标常数仍然适用。     

南水北调中线干渠浮游植物群落时空格局及其决定因子

为了解南水北调中线干渠浮游植物群落的时空格局,自2018年8月开始分4个季度对干渠沿程的11个样点进行采样调查,同步开展水环境调查;共检出浮游植物7门83属145种,物种丰富度上,硅藻种类数最多,绿藻和蓝藻分别占第2和第3位,且春季＞秋季＞冬季＞夏季;优势种包括极小曲丝藻(Achnanthidum minutissim...