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171.
Abstract. This study examined the effect of CO2 on NaCl solubility in hydrothermal fluid, with the synthetic fluid inclusion technique. Fluid inclusions of 30–40 wt% NaCl and 5 mol % CO2 were synthesized, and their halite dissolution temperatures, Tm (halite), were measured. The solubilities of NaCl in CO2 -bearing aqueous fluid were obtained at 160–320C under vapor-saturated pressures. The Tm (halite) value in aqueous fluid with 5 mol % CO2 obtained in this study agrees with that of Schmidt et al. (1995), showing that 5 mol % CO2 reduces the solubility of NaCl by about 1 wt%.
Calculation of magnetite solubility suggests that 5–10 mol % CO2 decreases magnetite solubility by 4.5–8.9 % relative to the magnetite solubility in CO2-free solution. Therefore, an increase of CO2 content in ore-forming solutions may cause deposition of iron minerals and produce ore deposits. 相似文献
Calculation of magnetite solubility suggests that 5–10 mol % CO2 decreases magnetite solubility by 4.5–8.9 % relative to the magnetite solubility in CO2-free solution. Therefore, an increase of CO2 content in ore-forming solutions may cause deposition of iron minerals and produce ore deposits. 相似文献
172.
宁夏固原硝口-寺口子盐矿地层复杂,上部古近系清水营组存在厚约150 m的红色泥岩夹石膏层,水敏性强,孔壁稳定性差,易出现坍塌和缩径,造成卡钻和抱钻事故;下部白垩系乃家河组含芒硝矿层及岩盐矿层,揭露厚度达380多米,水溶性强,孔壁易溶蚀形成“大肚子”、护壁难、钻进效率低、取心质量差。针对以上施工难题,从钻孔结构、钻头选型、钻井液和钻进参数等方面着手研究,建立了一套适合盐矿施工的绳索取心钻进工艺技术,有效地维护了孔壁稳定,实现了高效、高质、安全钻进,为今后施工类似钻孔积累了经验。 相似文献
173.
石英在热水溶液中的溶解度对地球化学和岩石学的研究都极为重要.我们提出一个能够适用于H2O-CO2-NaCl 复杂流体成分,高温高压(0~ 1000℃,0~ 1.5GPa)条件下的石英溶解度计算模型,形式如下:logmSiO2=A(T)+B(T)·logMH2O/V*H2O+C(t)? logxH2O 其中A(T)、B(T)、C(t)均为温度T(K)和t(℃)的多项式.xH2O和V*H2O分别代表流体中水的摩尔分数和有效偏摩尔体积.V*H2O值由公式Vmix=xHOV*H2O+∑xsVs计算得到.其中,Vmix代表流体混合物的摩尔体积,由Mao et al.(2010)的最新模型计算得到,xs和Vs分别代表溶质的摩尔分数和本征体积.具体采用VCO2=29.9cm3/mol、VNaCl=30.8cm3/mol.本模型精度较前人模型有所提高,并且适用深达下地壳的温度-压力-成分环境,如:巴罗式变质带、板块俯冲带等.另外,本模型可被用于建立石英地质温度计,加深人们对于石英脉及有关矿床成因的认识,并且可用来指导实验及工程.本模型的在线计算程序可通过以下网站获得:www.geochem-mode1.org. 相似文献
174.
《Comptes Rendus Geoscience》2014,346(11-12):317-325
Major features of the Earth's structure and dynamics originate in the contrast between the rigidity of SiO bonds and the softness of SiOSi linkages. Because this contrast results from orbital hybridization, a real understanding of bonding relies on ab initio quantum-mechanical principles. As investigated with first-principles interatomic potentials, the α–β transitions of SiO2 polymorphs illustrate how soft SiOSi linkages give rise to dynamical structures at rather low temperatures and yield the low melting temperatures of SiO2-rich minerals that are at the roots of SiO2 enrichment in magmatic differentiation. The increasing concentration of alkalis throughout this process is another aspect that must also be studied in terms of molecular orbitals in relation with the presence of aluminum in tetrahedral coordination. Finally, calculations of noble gas solubility show that some important features can be treated with “hybrid” calculations when, in addition to quantum-mechanical effects, the energy needed to create a cavity in the silicate melt is dealt with in a classical manner. 相似文献
175.
J. L. Mosenfelder 《Physics and Chemistry of Minerals》2000,27(9):610-617
The solubility of hydroxyl in coesite was investigated in multianvil experiments performed at 1200 °C over the nominal pressure
range 5–10 GPa, at an f
O2 close to the Ni-NiO buffer. The starting material for each experiment was a cylinder of pure silica glass plus talc, which
dehydrates at high P and T to provide a source of water and hydrogen (plus enstatite and excess SiO2). Fourier-transform infrared (FTIR) spectra of the recovered coesite crystals show five sharp bands at 3606, 3573, 3523,
3459, and 3299 cm−1, indicative of structurally bonded hydrogen (hydroxyl). The concentration of hydrogen increases with pressure from 285 H/106 Si (at 5 GPa) to 1415 H/106 Si (at 10 GPa). Assuming a model of incorporation by (4H)Si defects, the data are fit well by the equation C
OH=Af
2
H2<\INF>Oexp(−PΔV/RT), with A=4.38 H/106 Si/GPa, and ΔV=20.6 × 10−6 m3 mol−1. An alternative model entailing association of hydrogen with cation substitution can also be used to fit the data. These
results show that the solubility of hydroxyl in coesite is approximately an order of magnitude lower than in olivines and
pyroxenes, but comparable to that in pyropic garnet. However, FTIR investigations on a variety of ultrahigh pressure metamorphic
rocks have failed in all cases to detect the presence of water or hydrogen in coesite, indicating either that it grew in dry
environments or lost its hydrogen during partial transformation to quartz. On the other hand, micro-FTIR investigations of
quartz crystals replacing coesite show that they contain varying amounts of H2O. These results support the hypothesis that preservation of coesite is not necessarily linked to fast exhumation rates but
is crucially dependent on limited fluid infiltration during exhumation.
Received: 23 August 1999 / Accepted: 10 April 2000 相似文献
176.
177.
在H.C.Helgeson等人根据热力学导出的简单矿化物(MS型)溶解度公式的基础上,引进了ψ函数,考虑了氧化还原电位Eh对溶解度的影响,导出了新的硫化物溶解度公式。 相似文献
178.
近年来地质证据和少量的实验研究证实, 相当量的铜可以在气相中迁移, 人们认识到铜在气相中迁移是一种重要的地球化学过程, 但目前关于铜在气相中溶解反应机理的研究还相当缺乏.本文通过溶解度法, 在310~350℃, 压力为4.2~10MPa的条件范围内, 实验研究了铜在不饱和水蒸气相中的溶解度.结果表明: 水蒸气的存在大大增强了铜在气相中的溶解度; 恒定温度下, 铜在气相中的溶解度随着水蒸气压的增加而增大; 气相中铜可能以水合物的形式存在, 铜在气相中的溶解可由以下反应表述: CuClmsolid+nH2O gas=CuClm·(H2O)ngas(m=1, 2), 其中水合数随着温度升高而下降, 温度为310℃水合数n为~6, 330℃为~5, 350℃为~4.研究结果明确显示, 气体溶剂H2O与铜之间的反应可大大增强铜在气相中的溶解和迁移能力. 相似文献
179.
结合MEIC大气污染物排放源清单,利用耦合了大气化学模式的中尺度气象数值模式WRF-Chem,对2016年5月6日广东地区一次深对流天气过程及其大气化学气体成分变化进行模拟,着重研究深对流系统对大气化学气体成分再分布的影响。结果表明:数值模拟较真实地再现了这次深对流天气过程中大气污染物的时空分布特征。通过计算,评估了这次对流降水对不同溶解度的大气污染气体的湿清除效率,发现湿清除过程对低溶解度大气污染气体CO、NO_2和O_3的湿清除效率几乎可以忽略不计,而对SO_2、H_2O_2和HNO_3的湿清除效率则分别达到50.8%、98.6%和38.2%。随着溶解度的增大,清除效率并不一定增大,这是因为大气物理和化学过程共同影响着气体污染物的清除效率。 相似文献