泥鳅对铀的富集、释放和生物富集规律的研究   总被引：2，自引：1，他引：1  

罗明标  郑荣光  曾义昆 《华东地质学院学报》2000,23(1):49-51

试验在半静态条件下 ,研究了泥鳅鱼对铀的富集、释放和生物规律。测出泥鳅对铀的生物富集系数 (BCF) ,铀在泥鳅体内的释放过程可用双区一级动力学模型很好地描述 ,并得出表达式。  相似文献   

油气成藏动力学及其研究进展   总被引：141，自引：3，他引：138  

郝芳  邹华耀  姜建群 《地学前缘》2000,7(3):11-21

成藏动力学是综合利用地质、地球物理、地球化学手段和计算机模拟技术 ,在盆地演化历史中和输导格架下 ,通过能量场演化及其控制的化学动力学、流体动力学和运动学过程分析 ,研究沉积盆地油气形成、演化和运移过程和聚集规律的综合性学科。成藏动力学研究的基础是盆地演化历史和流体输导格架 ,研究的核心是能量场 (包括温度场、压力场、应力场 )演化及其控制的化学动力学和流体动力学过程。 2 0世纪 90年代以来 ,成藏动力学研究的进展表现在 :( 1)流体输导系统预测能力的提高 ;( 2 )能量场演化机制及其控制的化学动力学过程和流体流动样式研究的深入 ;( 3)油气成藏机理研究的深化 ;( 4 )计算机模拟技术的改进。在进一步认识与油气成藏密切相关的化学动力学和流体动力学过程和机理的基础上 ,实现盆地温度场、压力场、应力场的耦合和流体流动、能量传递和物质搬运的三维模拟 ,是成藏动力学的重要发展方向。  相似文献   

MgO.1.5B2O3-18%MgCl2-H2O过饱和溶液0°C的结晶动力学研究          下载免费PDF全文

刘兴起  张辉 《盐湖研究》2000,8(2)

配制MgO·1.5B2 O3- 18%MgCl2 -H2 O过饱和溶液在 0°C恒温静止 ,对该过饱和溶液结晶析出多水硼镁石 (2MgO·3B2 O3·15H2 O)的动力学过程进行了研究。结晶诱导期较长 ,晶体生长缓慢 ,结晶达平衡需要较长时间。探讨了析出固相的结晶反应机理和硼在溶液中的存在形式 ,并拟合给出结晶动力学方程  相似文献   

白云岩成因相关问题及主要形成模式   总被引：23，自引：5，他引：18  

张学丰  胡文瑄  张军涛 《地质科技情报》2006,25(5):32-40

在综述白云岩成因研究历程和最新成果的基础上,总结阐述了与之相关的4个方面的问题:①尽管白云岩原生沉淀与次生交代成因分歧依旧,但越来越多的证据表明白云岩的形成以次生交代为主;②白云石难以直接沉淀的原因是受结晶动力学条件制约,而非热力学因素;③控制次生交代强度和规模的关键条件是富Mg流体的来源及其量的大小;④微生物活动很可能有助于白云岩的形成。关于白云岩化模式,其核心是构建富Mg流体与先成钙质碳酸盐岩相互作用的条件与场所,其中浓缩正常海水模式、萨布哈模式、混合水模式和埋藏白云岩化模式等具有一定的普遍性。理清白云岩成因问题,对于认识以白云岩及其相关的碳酸盐岩为储层的油气勘探工作尤为重要。  相似文献   

On the total kinetic energy of our galaxy     

S. Ninkovi&#x; 《Astronomische Nachrichten》1992,313(2):83-89

The total kinetic energy of the Galaxy is estimated from the potential energy by applying the virial theorem. The limits of the potential energy depend strongly on the value of the local escape velocity. They are estimated to be between −7. 10¹⁶ M_Ȯ km²s⁻² and −1. 10¹⁶ M_Ȯ km²s⁻² (escape velocity approximately between 450 km s⁻¹ and 600 km s⁻¹). The specific kinetic energy of the Galaxy as a whole is most likely about 21 000 km²s⁻², being equally distributed among the subsystems if the local escape velocity is near its lower limit; the higher the local escape velocity is, the higher is the specific kinetic energy of the Galaxy due to the influence of the dark corona. The specific kinetic energy of the dark corona tends to become equal to that of the Galaxy as a whole for very high values of the local escape velocity. For the purpose of estimating the totl potential energy of the Galaxy, inter alia, a new model of the Milky Way is developed, which yields both the potential and the density analytically so that it is suitale for calculating the galactocentric orbits.  相似文献   

免像控无人机在地形图测量中的应用     

刘书林  黄磊 《北京测绘》2020,(2):243-245

通过eBeePlus免像控无人机航空摄影测量系统应用于1∶500地形图测绘工程实例,探究其在实践中的制图精度及适用性。使用emotion3、Pix4dMapper等软件进行外业航飞、内业影像处理,对比分析RTK和PPK两种解算方式下的制图精度,两者均满足规范要求,PPK解算方式更适宜在实践中使用;结合Eps软件制作数字线划地图,对于影像中无法提取的房屋边线、植被覆盖区域地物,采取全野外调绘、实测进行补充,阐述了无人机航测与传统数字化测图相结合的作业方式。  相似文献   

A Kinetic model of crack fusion     

Zbigniew Czechowski 《Geophysical Journal International》1991,104(2):419-422

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Kinetics of the reactions of hydroxyl radicals with aliphatic ethers studied under simulated atmospheric conditions: Temperature dependences of the rate coefficients     

Paul J. Bennett  J. Alistair Kerr 《Journal of Atmospheric Chemistry》1990,10(1):27-38

Rate coefficients have been measured for the reactions of hydroxyl radicals with five aliphatic ethers over the temperature range 242–328 K. Competitive studies were carried out in an atmospheric flow reactor in which the hydroxyl radicals were generated by the photolysis of methyl nitrite in the presence of air containing nitric oxide. The reaction of OH with 2,3-dimethyl-butane was used as the reference reaction and the following Arrhenius parameters have been obtained for the reactions: OH+RORproducts:

ROR	E/kJ mol–1	1012 A/cm3 molecule–1 s–1
dethyl ether	–2.8±0.4	3.5±0.6
di-n-propyl ether	–1.2±0.6	11.5±2.7
methylt-butyl ether	0.85±0.59	4.0±1.3
ethyln-butyl ether	–1.3±0.5	8.7±1.7
ethylt-butyl ether	–1.2±0.6	3.0±0.8

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Kinetic Modeling the Formation of Low-mature Gases and Analysis of the Possibility to Be Accumulated     

SHUAI Yanhu  WANG Hui  ZHANG Shuichang  SU Aiguo 《《地质学报》英文版》2008,82(3):537-542

At present, shallow gases have received much attention due to low cost in exploration and production. Low-mature gases, as one significant origin to shallow gas, turns to be an important research topic. The present understanding of low-mature gases is confined within some geological cases, and few laboratory studies have been reported. Therefore, the potential and characters of low- mature gases are not clear up to now. Here, two premature samples （one coal and the other shale） were pyrolyzed in a gold confined system. The gaseous components including hydrocarbon gases and non-hydrocarbon gases were analyzed. Based on kinetic modeling, the formation of low-mature gases was modeled. The results showed that during low mature stage, about 178 mL/gTOC gas was generated from the shale and 100 mL/gTOC from the coal. Two third to three fourth of the generated gases are non-hydrocarbon gases such as H2S and CO2. The total yields of C1-5 for the two samples are almost the same, 30-40 mL/gTOC, but individual gaseous hydrocarbon is different. The shale has much lower C1 but higher C2-5, whereas the coal has higher C1 but lower C2-5. Hydrocarbon gases formed during low-mature stage are very wet. The stable carbon isotope ratios of methane range from -40‰ to -50‰ （PDB）, in good consistence with empiric criterion for low-mature gases summed up by the previous researchers. The generation characters suggest that the low-mature gases could be accumulated to form an economic gas reservoir, but most of them occur only as associated gases.  相似文献   

A Simple Kinetic Model for Autoxidation of S(IV) Oxides Catalyzed by Iron and/or Manganese Ions     

Irena Grgić  Gorazd Berčič 《Journal of Atmospheric Chemistry》2001,39(2):155-170

The reaction kinetics of S(IV) autoxidation catalyzed by single metal ions of Mn(II) and Fe(II) or Fe(III) and by a mixture of Mn(II) and Fe(II) under the conditions representative for acidified atmospheric liquid water was investigated. A simple power law kinetic model based on the stability constants for metal-sulfito complexes formed during the first step of a radical chain mechanism predicts well the kinetics for the reactions catalyzed by single metal ions. The calculated stability constants for iron (5.7×10³ dm³ mol^–1) and manganese (10×10⁴ dm³ mol^–1) sulfito complexes are close to those reported in the literature. The catalytic synergism between Mn(II) and Fe(II) was confirmed. For this system the following power law rate equation was suggested:r_tot = S_Fe · r_Fe + S_Mn · r_Mn ,where r_Fe and r_Mn are the reaction rates in the presence of Fe(II) and Mn(II), respectively. S_Fe and S_Mn are proportional factors, which account for the synergistic effect. The proposed power law rate equation predicts the reaction kinetics very well. The values of S_Fe (1.35) and S_Mn (15) indicate that the influence of Fe(II)/Fe(III) on Mn(II)/Mn(III) cycling is larger than, vice versa, agreeing with the reaction mechanism proposed for the S(IV) autoxidation catalyzed by mixed metal ions.  相似文献