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排序方式: 共有2510条查询结果,搜索用时 15 毫秒
1.
为有效管理和利用矿井长期积累的大量水化学数据,介绍了基于Microsoft Excel的数据管理方法。该方法既方便水化学特点分析,也有利于质量标准化建设,设计的数据表可作为模板供生产单位防治水技术人员使用。通过应用实例说明了水化学数据在防治水工作中的重要性,同时,也证明传统简单分析方法仍是常用且有效的方法。 相似文献
2.
W. J. Collins D. S. Stevenson C. E. Johnson R. G. Derwent 《Journal of Atmospheric Chemistry》1997,26(3):223-274
A three-dimensional Lagrangian tropospheric chemistry modelis used toinvestigate the impact of human activities on the tropospheric distributionofozone and hydroxyl radicals. The model describes the behaviour of 50 speciesincluding methane, carbon monoxide, oxides of nitrogen, sulphur dioxide andnineorganic compounds emitted from human activities and a range of other sources.Thechemical mechanism involves about 100 chemical reactions of which 16 arephotochemical reactions whose diurnal dependence is treated in full. The modelutilises a five minute chemistry time step and a three hour advection timestepfor the 50,000 air parcels. Meteorological data for the winds, temperatures,clouds and so on are taken from the UK Meteorological Office global model for1994 onwards. The impacts of a 50% reduction in European NOXemissions onglobal ozone concentrations are assessed. Surface ozoneconcentrations decrease in summertime and rise in wintertime, but to differentextents. 相似文献
3.
CHEN Biying FANG Luji LANG Yunchao XU Sheng LIU Congqiang ZHANG Luyuan HOU Xiaolin 《《地质学报》英文版》2024,98(1):207-219
The knowledge of the residence time of formation water is fundamental to understanding the subsurface flow and hydrological setting. To better identify the origin and evolution of coal seam water and its impact on gas storage and production, this study collected coalbed methane co-produced water in the southeast Qinshui Basin and detected chemical and isotopic compositions, especially 36Cl and 129I concentrations. The calculated tracer ages of 129I (5.2–50.6 Ma) and 36Cl (0.13–0.76 Ma) are significantly younger than the age of coal-bearing formation (Pennsylvanian - Cisuralian), indicating freshwater recharge after coal deposition. The model that utilises 129I/I and 36Cl/Cl ratios to constrain the timing of recharge and the proportion of recharge water reveals that over 60% of pre-anthropogenic meteoric water entered coal seams since 10 Ma and mixed with residue initial deposition water, corresponding to the basin inversion in Cenozoic. The spatial distribution of major ion concentrations reveals the primary recharge pathway for meteoric water from coal outcrops at the eastern margin to the basin center. This study demonstrates the occurrence of higher gas production rates from wells that accept water recharge in recent times and suggests the possible potential of the non-stagnant zones for high gas production. 相似文献
4.
In the atmospheric Čerenkov technique γ-rays are detected against the abundant background produced by hadronic showers. In
order to improve the signal to noise ratio of theexperiment, it is necessary to reject a significant fraction of hadronic
showers. Traditional background rejection methods based on image shape parameters have been extensively used for the data
from imaging telescopes. However, non-imaging Čerenkov telescopes have to develop very different means of statistically identifying
and removing cosmic ray events. Some of the parameters, which could be potentially important for non-imaging arrays, are the
temporal and spectral differences, the lateral distributions and density fluctuations of Čerenkov photons generated by γ-ray
and hadron primaries. Here we study the differences in fluctuations of Čerenkov photon density in the light pool at the observation
level from showers initiated by photons and those initiated by protons or heavier nuclei. The database of simulated events
for the PACT array has been used to evaluate the efficiency of the new technique. Various types of density fluctuations like
the short range and medium range fluctuations as well as flatness parameter are studied. The estimated quality factors reflect
the efficiencies with which the hadrons can be rejected from the data. Since some of these parameters are independent, the
cuts may be applied in tandem and we demonstrate that the proton rejection efficiency of ∼90% can be achieved. Use of density
fluctuations is particularly suited for wavefront sampling observations and it seems to be a good technique to improve the
signal to noise ratio.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
6.
Study of Metal Distribution in Raw and Screened Swine Manure 总被引:1,自引:0,他引:1
Ricardo Luís Radis Steinmetz Airton Kunz Valderi Luiz Dressler Érico Marlon de Moraes Flores Ayrton Figueiredo Martins 《洁净——土壤、空气、水》2009,37(3):239-244
The growth of industrial swine production over the last few years has led to a growth in concern over effluents generated by the activity. Several elements, mainly toxic metals, can be present in swine wastewater and can have a serious environmental impact. It is important, therefore, to know the metal concentration before the discharge of wastewater. In this work the temporal metal distribution in swine manure and its potential reduction using coarse (2 mm) and fine (<0.45 μm) liquid‐solid separation techniques were investigated. In order to do this, different swine manure sample preparation methods for Al, Ba, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr and Zn determination by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) were tested. The acid mixtures used to digest the manure sample significantly affected the metal recovery. Good analyte recoveries were observed with nitric acid/hydrogen peroxide mixtures or nitric acid/perchloric acid mixtures. Sulfuric acid/hydrogen peroxide mixtures produced inconsistent results and poor recoveries, mainly for Ba and Pb. It was observed that metal concentrations in swine manure varied greatly with time, up to one order of magnitude, due to changes in swine production such as feed and animal numbers. Metals concentrations observed in the raw wastewater exceeded Brazilian limits for discharge into water bodies and recommendations for agricultural use. Results obtained from the liquid‐solid separation study showed that metals in the raw swine manure were not removed with coarse screening. However, the major fraction of metals were removed by filtration (0.45 μm), with the exception of Na, K and Sr. Thus, the use of liquid‐solid separation techniques that capture the fine solid fractions (and associated metals) from raw manure can have a favorable impact on the environment and contribute to swine production wastewater treatment. 相似文献
7.
巴丹吉林沙漠湖泊及地下水化学特征 总被引:7,自引:0,他引:7
通过对巴丹吉林沙漠丘间湖泊和古日乃、雅布赖、阿拉善右旗等地及其周围浅层地下水离子化学成分分析,探讨了沙漠地区湖水与地下水化学成分特点、水化学类型、空间变化和湖水补给来源。结果显示,巴丹吉林沙漠湖泊水的pH、盐度、TDS和电导率均远远大于地下水。湖水样品中Na+和Cl-含量占绝对优势,大多数盐度较高的湖泊属于Na(K)-Cl-(SO4) 型,个别盐度较低的微咸湖属于Na-(Mg)-(Ca)-Cl-(SO4)-(HCO3) 型。地下水的化学类型多数为Na-(Ca)-(Mg)-Cl-(SO4)-(HCO3)型,属微咸水,个别为Na-Cl-SO4型的咸水。沙漠东南部湖群水的pH值、盐度、TDS和电导率比较低,呈微碱性,属微咸湖;而北部湖群水的pH、盐度、TDS和电导率远远大于东南部湖群,呈中等碱性,为盐水湖。湖水离子化学特征显示沙漠东南部湖群自南向北的演化趋势为:微咸湖→咸水湖→盐水湖。湖水离子化学成分短时间序列变化指示,近9 年宝日陶勒盖、巴丹东湖、巴丹西湖、诺尔图、呼和吉林湖水中的大多数离子的含量有所降低,表明其近9 年来淡水补给量增多。湖水化学成分与湖水位高度显示,巴丹吉林沙漠湖群湖水流向是由东南流向西北。水化学成分和水位分布高度表明,该区沙漠湖水主要来自当地降水补给和来自沙漠东南缘雅布赖山和南缘的黑山头山地降水的补给,而来自祁连山区来水补给的可能性很小。 相似文献
8.
CCSD主孔榴辉岩中磷灰石的矿物化学特征及对榴辉岩中F、Cl、Sr等元素地球化学行为的影响 总被引:9,自引:1,他引:9
为探讨榴辉岩中磷灰石的矿物化学特征及榴辉岩中某些相关元素的地球化学行为,对中国大陆科学钻探(CCSD)主孔500~540m深度的榴辉岩样品进行了岩石化学及磷灰石的矿物化学分析。这些榴辉岩具有不同的矿物组成和化学成分,并可据此分为上下两段,上段500~530m为正常榴辉岩,下段530~540m为高Ti榴辉岩和高Ti-Fe榴辉岩,其原岩可能为类似于辉长质和苦橄质的基性—超基性岩石。其中的磷灰石成分没有明显差别,均为氟—磷灰石,其富F贫Cl的特征可能是造成榴辉岩中高盐度流体包裹体和全岩高F低Cl的主要原因。磷灰石普遍含有一定的Sr、S、Fe元素,多数还含有Cu、Pb、Zn等元素。榴辉岩中P2O5含量与其F、Cl、Sr、S元素的相关程度表明,磷灰石是榴辉岩中F元素的最主要储存库,也是Sr元素的重要储存库之一,而对于Cl元素则只是部分控制,与S元素则没有相关性。榴辉岩中F、Sr及Cl元素的地球化学行为主要受控于磷灰石,因此,在榴辉岩从进变质—退变质过程中,这些元素的活动性直接受控于磷灰石的稳定性。 相似文献
9.
S.?PetitEmail author A.?Decarreau F.?Martin R.?Buchet 《Physics and Chemistry of Minerals》2004,31(9):585-592
The aim of this paper is to determine a relationship between the wavenumbers of the first OH-stretching overtones (W2OH) and the wavenumbers of the OH-stretching fundamentals (WOH) to help to interpret the near-infrared (NIR) spectra. The first overtone (2OH) bands appear at wavenumbers less than twice those of the fundamental bands (OH), due to the anharmonic character of vibrations, X = W2OH/2 - WOH, with X being the anharmonicity constant. Talc samples with various crystal chemistries are used to solve the equation and the experimental data are well fitted with X = –85.6 cm–1. As far as the authors are aware, it is the first time that the anharmonicity constant for the OH-stretching vibrations is determined for phyllosilicates. The anharmonicity constant remains almost unchanged for several types of clay samples. Therefore the relation, established from talc samples because their absorption bands are narrow and their wavenumber range of OH vibrations is wide, can be used for any other clay minerals. 相似文献
10.
四川平武板状绿柱石矿物学特征及板状成因 总被引:7,自引:0,他引:7
在综合该区绿柱石产出背景的基础上,从围岩蚀变、矿物共生组合、矿物标型形态和绿柱石测温测压等方面确定平武绿柱石矿床是气成高温浅成石英脉型矿床。文中对绿柱石矿物进行了湿法化学分析、X射线粉晶衍射分析、微形貌分析,研究了该区绿柱石的形态、物性、化学成分及类质同象特征,确定该区绿柱石为板状晶形的含铯钠锂绿柱石,碱金属平均质量分数为2.412%(Li2O+Na2O+K2O+ Rb2O+Cs2O)。板状含碱绿柱石一般发育在伟晶岩中,气成高温热液矿床中产出板状含碱绿柱石极为罕见。在以上工作基础上,从绿柱石形成的内因和外因两方面探讨了绿柱石的板状成因。 相似文献