自组织神经网络用于地质样品分类

地质样品的分类是地质学中一个重要问题。本文提出用一种神经网络———ART2模型来实现自动分类。该方法简单、实用,分类效果令人满意。网络的应用结果显示出它具有良好的获得最佳分类数和最佳分类的双重功能。     

南海中部柱状沉积样中的氨基酸

本文通过对南海中部柱状沉积样中氨基酸的研究，阐述了各类氨基酸组分随岩芯深度而变化的分布规律，以及它们与其它一些参数诸如Ｃ、Ｎ、碳酸盐、蛋白石、有机碳等的相应关系。同时也讨论了出现这些情况的原因、机制。由此提供了不同地质年代沉积环境的有关信息。     

Observation of corer penetration and sample entry during gravity coring

Gravity core samples provide the basic data source for a wide range of geological, geotechnical and geochemical studies. However, the length of the core recovered is often less than the penetration achieved by the corer, such cores being described as shortened. If the penetration of the corer has been measured, and it is assumed that no dropout of the core occurs as the barrel is withdrawn from the seabed, it is present practice to reconstruct in situ dimensions using an overall correction factor based on this penetration and the length of core recovered. However, measurements, reported here, have been made of corer penetration and sample entry and these show that the entry deficit (penetration minus sample entry) develops in some instances continuously, and in others intermittently. These results indicate that an overall correction factor is unlikely to be appropriate to any given section of the core.     

功率谱分析中几个重要问题的讨论

本文从理论上推导了谱分析中最大后延M的取值,并且从理论和实际计算中得出了样本长度和其隐含周期之间的关系。只要抽样是平稳的,样本长度并非一定要求太长,仅略为超过其隐含周期的长度即可。但谱分析绝非是万能的。如果样本中仅含有两个波动,且当这两个波动的周期相差一个整数倍或更大时,这两个波动才可以通过谱分析分辨出,反之就会歪曲了其隐含周期。由此可见,在具体应用时,应作一些滤波和去掉趋势是必要的。因而这将对广大气象、地理科学工作者以及其它相邻学科的科研工作者具有重要的参考价值。     

Storage diagenesis versus sulphide authigenesis: possible implications in environmental magnetism

Experiments involving the gradual drying out of controlled mixtures of soil and organic lake sediment during storage at room temperature show that this leads to a loss of magnetic susceptibility and isothermal remanence greatly in excess of the initial values for the sediment components of the mixtures. We conclude that during storage in the moist state, soil-derived, fine-grained, ferrimagnetic iron oxides (magnetite and/or maghemite) are transformed to paramagnetic and/or imperfect antiferrimagnetic minerals. The imperfect anti-ferromagnetic component of the initial mixtures, which probably includes goethite, appears to survive and may even increase during storage. The experimental results compare well with the previously documented effects of storing wet sediment from the site, Peckforton Mere, Cheshire, U.K., over a comparable time interval. We conclude that transformation of fine grained ferrimagnets during storage diagenesis may be responsible for many of the examples of loss of magnetic susceptibility and remanence attributed by other authors solely to the oxidation of an iron sulphide such as greigite. Only where greigite is positively identified is it valid to infer a contribution from it to the magnetic properties of lake sediments: loss of susceptibility or remanence during storage is not alone a sufficient basis for such an inference. Early drying of samples will normally avoid the effects of storage diagenesis; and recent sediment samples so treated will, where greigite formation, bacterial magnetite and magnetite dissolution are insignificant, provide a valid basis for source identification on the basis of magnetic properties.     

微波消解-氢化物发生原子荧光光谱法测定植物样品中硒

植物样品经微波消解，在硝酸介质中采用氢化物发生一原子荧光光谱法测定硒。方法精密度（RSD，n=12）为4．36％，硒的检出限为0．008mg／kg。方法经植物样品国家一级标准物质验证，结果与标准值吻合。对5种42个植物样品的硒含量进行了测定，所得结果与外检结果一致。     

地球化学样品中有机农药残留分析预处理方法新进展

在对地质样品进行有机农药残留分析的过程中,样品预处理是重要的步骤之一。概述了近年来样品预处理方法的新进展,简要介绍并对比了固相萃取(SPE)、固相微萃取技术(SPME)、微波提取技术(MAE)、超临界萃取(SFE)、加速溶剂提取(ASE)等方法。     

含金地质样品的均匀性及代表性研究

近年来对金矿石的制样研究认为，金测定精密度和准确度较低的主要原因是样品加工中存在的问题。因此，研究不同类型的金矿石制样，改进加工流程，是保证金分析质量的前提．通过对甘肃李子园、小沟里、三洋坝等秦岭山脉区的粗颗粒性金矿石的制样研究，制定出了比较合理的制样流程。     

近红外反射光谱学在岩石矿物研究中的应用——Ⅰ．快速测定地质样品中化合水

应用近红外反射光谱学方法无损快速测定了各种地质样品中化合水。使用偏最小二乘回归法，在近红外波长范围分离出与化合水含量有关的光谱信息。大多数地质样品的近红外反射光谱估算结果与重量法吻合。实验结果表明，近红外反射光谱学测定地质样品中化合水更简单、更容易。     

堆浸生产中高锑样品金的测定

在堆浸提金生产中，应用高锑样品的湿法测金方法，用氯化铵和溴化氢挥发法除去锑对金测定的干扰，用氢醌容量法测定，快速、简单、效果明显。