氯化物解聚快速测定铁矿石中二氧化硅

采用NaOH熔融、蒸馏水浸取、盐酸中和并酸化、氟化物解聚和钼酸铵显色测定铁矿石中的二氧化硅。本方法的检出限为0．10％。本实验以测定了国家一级铁矿标样来验证方法的准确度和精密度,测定结果与标准值相符,且测定12次的相对标准偏差（RSD）均小于10％。     

Estimation of ecological flow requirement in Zoige Alpine Wetland of southwest China

In many vulnerable wetlands, water is the most crucial factor for sustaining human development, economic growth, as well as existence and evolution of various indigenous ecosystems. This has led to intensive competitions against limited water resources and caused a number of potentially adverse effects on local ecosystems and human society. As water demand by human activities is increasing, balancing water demands between human society and ecosystems is desired to improve economic development without causing too much disturbance on the environment and ecosystems within a wetland. In this study, a computationally efficient quantitative method was developed to calculate the ecological flow requirement (i.e., water demand by ecosystems) in an alpine wetland of western China. The proposed method was also carried out by means of remote sensing images interpretation. Through this method, variations in water demands by human beings and ecosystems could be reflected and analyzed, which would be useful in helping formulate water allocation strategies under multiple objectives such as environmental protection, economic development, and ecological conservation. The method was then applied to assess ecological flow requirements in Zoige Wetland of western China. The results indicated that to maintain the basic ecological structure and integrity of the wetlands, the minimum reserve of 6.218 billion m³/a and a suitable reserve of 6.639 billion m³/a of water would be required. Also, the application results indicated that the method is applicable and can be expanded to other similar wetlands for balancing water demands between ecosystems and human beings.     

世界各国太阳射电望远镜概况

详细汇总了国内太阳射电望远镜的技术性能及原理框图。收集了部分国外太阳射电望远镜技术指标。对射电望远镜系统参数灵敏度、信噪比、交叉计划隔离度的计算方法作了介绍。     

Evaluations on the relation of RC building damages with structural parameters after May 19, 2011 Simav (Turkey) earthquake

An earthquake has struck Simav, Kutahya, located in the western part of Turkey on May 19, 2011. This paper focuses on the evaluation of the regional damage data and detailed investigation on a set of selected reinforced concrete buildings in Simav county center. The soil properties in Simav are examined in detail using multi-channel analysis of surface wave measurements, boreholes and laboratory test data. The damages are observed to be independent of soil conditions being hilly or plain, both in regional and Simav county center level. However, a slight relation is observed: as the soil period increases, so does the damage. The most damaged buildings are the four story buildings, resembling the case after some other earthquakes in Turkey. Regarding the detailed numerical evaluations on the building set, the properties highly correlated with seismic damage are investigated. Based on the obtained findings, it is concluded that the global building properties may not be enough to establish a strong relation with damage due to the local damages at the structural member level, especially for smaller seismic events.     

Quantitatively analyze the impact of land use/land cover change on annual runoff decrease

Annual runoff in Luanhe river basin was detected a downward trend and caused water crisis in Tianjin, China. To quantify the decreased runoff volume, Mann–Kendall test and Pettitt test were employed to check whether there existed significant trend and change points for annual rainfall and runoff time series in Panjiakou reservoir basin and 8 sub-watersheds. It was found that the annual runoff time series had a significant downward trend at 5 % confidence level, and the change point was at 1979 in Panjiakou reservoir watershed. Then double mass curve of annual rainfall and annual runoff was plotted, and two lines were fitted before and after 1979, respectively. Based on this method, the comprehensive effects of land use/land cover change on annual runoff were estimated. To further quantify the contributions of each main factor to annual runoff decrease, water stored in check dams and social water use in different periods were surveyed first. And then multi-linear regression was used to develop the relations between annual runoff and the driven factors. Water area decrease was identified to be the main factor contributing to annual runoff reduction. The results in this study can provide valuable information for water resources planners and policy makers.     

Influence of an Inclined Rock Stratum on In-Situ Stress State in an Open-Pit Mine

In-situ stress plays a major role with respect to deformation and stability around underground or surficial excavations located at significant depth. Many sedimentary rock masses are more or less horizontally bedded. However, a possibility exists to have one or few inclined rock strata such as dikes in these horizontally bedded formations. It is important to know how the in situ stress changes from a purely horizontally bedded situation to a horizontally bedded rock mass that contains one or few inclined rock strata. This paper presents such an investigation using the largest open-pit metal mine in China—as a case study. This mine has a bedded rock mass with one steeply inclined rock stratum. For the bedded rock mass, the vertical stress was calculated based on the overburden above each lithology. The available in situ stress measurements conducted at the mine were used to estimate the ratios of horizontal to vertical stress. Numerical modeling was performed for the two scenarios: (a) the horizontally bedded system subjected to both the in situ and boundary stresses and (b) the mine lithological system that includes an inclined stiffer (denser) stratum intruding softer horizontally bedded system subjected to only boundary stresses to investigate the influence of an inclined rock stratum on the computed stress field. Thirty points were selected to compute the stresses on six planes of the inclined rock stratum. Due to the discontinuous nature of the geologic system at the interface between the stiffer inclined stratum and softer horizontally bedded system, one principal stress has become normal to the interface plane and the other two have become parallel to the interface plane with all three being perpendicular to each other. Presence of the stiffer inclined rock stratum has given rise to (a) increase in normal stresses up to about 120 % in the inclined rock stratum and (b) new shear stresses approximately in the range ?10.0 to 15.0 MPa. This means, because most of the rock masses are not purely horizontally bedded, estimation of in situ stress through measurements as well as application of in situ stress in numerical modeling associated with underground or surficial excavations located at significant depth is a difficult exercise. A better way to estimate the in situ stresses for complex geologic systems may be through application of appropriate boundary stresses to the geologic system in a numerical model.     

基于附加参数模型的自检校光束法区域网平差算法运行结果对比

像点偏移是影响光束法区域网平差结果精度的主要因素之一。克服平差过程中像点偏移的影响,以提高区域网平差精度,一直受到业界高度重视。当前,克服像点偏移的常规做法是借助特定的参数模型对其进行描述,构建基于附加参数模型的自检校光束法区域网平差模型,在区域网平差的同时求解引入的参数,进而实现对系统误差的补偿。Bauer模型、Ebner模型、Brown模型、光学畸变模型是现有算法中描述像点偏移的常用模型。为了对上述4种模型的系统误差进行验证,本文首先在经典的光束法区域网平差模型基础上分别设计了与4种模型相对应的自检校光束法区域网平差模型,并予以编程实现;然后通过实例对上述4种模型的算法运行结果进行了验证、比较及分析。试验结果表明,Ebner模型和Brown模型的引入可有效提高光束法区域网平差的精度;Bauer模型的引入对小型区域网平差精度的提升更加有效;光学畸变模型的引入对区域网平差结果的精度提升作用相对较小。     

洞庭湖地区耕地功能时空演变特征及影响因素研究

耕地功能时空演变规律及影响因素研究是凸显耕地价值与作用、推动地区协调发展的重要科学依据。综合运用熵值法、地理探测器模型等方法,以湖南省洞庭湖地区24个县市区为研究区域,对该地区耕地功能的时空演变、空间分异及其影响因素进行研究。结果表明：① 1998—2018年洞庭湖地区耕地经济生产功能整体呈增强趋势,主要集中于洞庭湖地区中部、西南部等农业基础较好的区域;社会保障功能整体增强明显,仅有临澧县、津市市和鼎城区3个地区功能强度有所减弱;生态维护功能空间格局变化较小,整体呈中间高两边低的态势。② 自然地理条件是早期影响地区耕地功能的主要因素,随时间推移其影响能力逐渐弱化;社会经济发展到一定阶段,社会经济因素对耕地功能空间分异的影响能力逐渐增强,并凸显出决定性作用;耕地利用水平的不断提升,对耕地功能空间分异影响能力逐渐增强;不同因子之间的交互作用能够明显增强对洞庭湖地区耕地功能空间分异的解释力,共同推动地区耕地功能多元化发展。     

河南洛宁县铁炉坪银铅矿床地质特征及找矿标志

通过对铁炉坪银铅矿床地层、构造、岩浆岩及围岩蚀变等地质特征研究,认为矿体受花岗绿岩带及构造断裂带的联合控制,并受后期热液叠加改造,属海底火山喷发-变质热液改造块状硫化物型矿床,归纳总结其找矿标志,对熊耳山地区寻找同类型矿床具重要指导意义。     

Research on Accuracy Validation and Calibration Methods of TRMM Remote Sensing Precipitation Data in Irrawaddy Basin

TRMM daily precipitation data were validated compared to thirteen precipitation observation station data in Irrawaddy basin, and a calibration method of TRMM 3B42 data based on water balance concept was developed. SWAT model was used to calculate water balance, and then the TRMM data calibration ratio was inferred based on it. Average slope of sub-basin was the independent variable, and calibration ration was the dependent variable for the regression analysis. The calibration ratio of sub-basins without hydrological observation stations were calculated according to the average slope, and then the TRMM precipitation were calibrated according to the ratio in the whole basin. Results showed that TRMM annual and monthly precipitation had a highly correlation with observed data, but had a bad bias. Annual precipitation of TRMM precipitation after calibration were nearly the same as observed; monthly precipitation curve were similar with observed. Daily precipitation forecast rank was improved from medium to well, and there were 2 station forecast bad, 7 forecast well and 4 forecast medium before calibration, but 6 forecast well, 2 forecast medium and 5 forecast excellent after calibration. The results proved that TRMM data precision were highly improved over different temporal scales in Irrawaddy basin through this method, data for hydrological and water resources analysis were also provided.