Thermal expansion of gehlenite, Ca2Al[AlSiO7], and the related aluminates LnCaAl[Al2O7] with Ln=Tb, Sm     

L. Peters  K. Knorr  M. Knapp  W. Depmeier 《Physics and Chemistry of Minerals》2005,32(7):460-465

The thermal expansion of gehlenite, Ca₂Al[AlSiO₇], (up to T=830 K), TbCaAl[Al₂O₇] (up to T=1,100 K) and SmCaAl[Al₂O₇] (up to T=1,024 K) has been determined. All compounds are of the melilite structure type with space group Thermal expansion data was obtained from in situ X-ray powder diffraction experiments in-house and at HASYLAB at the Deutsches Elektronen Synchrotron (DESY) in Hamburg (Germany). The thermal expansion coefficients for gehlenite were found to be: α₁=7.2(4)×10⁻⁶ K⁻¹+3.6(7)×10⁻⁹ΔT K⁻² and α₃=15.0(1)×10⁻⁶ K⁻¹. For TbCaAl[Al₂O₇] the respective values are: α₁=7.0(2)×10⁻⁶ K⁻¹+2.0(2)×10⁻⁹ΔT K⁻² and α₃=8.5(2)×10⁻⁶ K⁻¹+2.0(3)×10⁻⁹ΔT K⁻², and the thermal expansion coefficients for SmCaAl[Al₂O₇] are: α₁=6.9(2)× 10⁻⁶ K⁻¹+1.7(2)×10⁻⁹ΔT K⁻² and α₃=9.344(5)×10⁻⁶ K⁻¹. The expansion-mechanisms of the three compounds are explained in terms of structural trends obtained from Rietveld refinements of the crystal structures of the compounds against the powder diffraction patterns. No structural phase transitions have been observed. While gehlenite behaves like a ’proper’ layer structure, the aluminates show increased framework structure behaviour. This is most probably explained by stronger coulombic interactions between the tetrahedral conformation and the layer-bridging cations due to the coupled substitution (Ca²⁺+Si⁴⁺)-(Ln ³⁺+Al³⁺) in the melilite-type structure. Electronic Supplementary Material Supplementary material is available for this article at  相似文献   

含油气岩系中含铵矿物研究现状与前景     

薛莲花  陈国俊  朱玉双  张晓宝 《沉积学报》2000,18(2):319-323

研究表明,在含油气岩系中,当有机质发生热演变而成熟、并逐渐向烃类转变的整个过程中,氮主要以NH+₄的形式释放出来而进入孔隙流体与周围介质 (成岩矿物 )相互作用,最重要的机制是NH+₄可取代粘土矿物 (如伊利石,I/S混层矿物等 )层间的K+而参与成岩作用,形成含铵矿物,这一过程中氮的地球化学性质发生了重要变化,含铵矿物中固定 -NH4的富集状况与有机质成熟度及烃类运移有关。通过研究成岩和油气生成、运移、聚集过程中氮的岩石地球化学行为及其控制因素,可将固定 -NH₄作为有机质成熟度和油气运移路径的一种新的、有意义的示踪剂。  相似文献   

The Satisfaction of Human Needs in Physical and Virtual Spaces     

Aharon Kellerman 《The Professional geographer》2013,65(4):538-546

This article attempts to explore the spatial dimension of Maslow's theory on the hierarchy of human needs, in light of the growing role of virtual space via the Internet in the contemporary information age. Generally speaking, virtual space constitutes a space for the gratification of human needs, side by side with physical space. Its role, as compared to physical space, grows along the hierarchy of human needs: physiology, safety, love and belonging, esteem, and self-actualization. Thus, its role for the gratification of physiological needs is complementary, whereas its role for self-actualization is significant. The growing role of virtual space has evolved into an equivalent hierarchical relationship with physical space: complementarity, competition, substitution, escape, and, potentially also exclusivity. Escape from physical to virtual space, as both need and relationship, has been brought about by social networking, being similar to the physical escape offered by tourism. It does not seem real to foresee that virtual space will offer exclusive fulfillment of as of yet unforeseen new human needs.  相似文献   

基于岩石物理实验的时移地震研究     

周水生  刘洪  王冲 《地球物理学进展》2013,28(4)

时移地震技术是油田开发阶段动态检测的一个重要手段.岩石物理实验室能实现模拟油气田在开采过程中其储层参数变化对岩石弹性参数的影响.本文基于岩石物理实验及地震正演模拟,分析了X气田在开采过程中其孔隙压力下降及水不断侵入情况下,进行时移地震监测的可行性及其主要影响因素.  相似文献   

地震尺度下碳酸盐岩储层的岩石物理建模方法(英文)   总被引：3，自引：3，他引：0  

李景叶  陈小宏 《应用地球物理》2013,10(1):1-13

碳酸盐岩油藏的强非均质性以及孔隙结构的复杂性,使得作为连接油藏参数与地震参数重要桥梁的岩石物理模型,以及作为油藏预测和定量表征最有效工具的流体替换成为岩石物理建模的难点与重点。在碳酸盐岩储层复杂孔隙结构与地震尺度下碳酸盐岩储层非均质性分析基础上,研究采用岩石网格化方法,将地震尺度下非均质碳酸盐岩储层岩石划分为具有独立岩石参数的均质岩石子体,根据岩石孔隙成因与结构特征采用不同岩石物理模型分步计算岩石子块干岩石弹性模量,并根据不同孔隙连通性进行流体替换,计算饱和不同流体岩石弹性模量。基于计算的岩石子块弹性模量,采用Hashin-Shtrikman-Walpole弹性边界计算理论方法实现地震尺度下碳酸盐岩储层弹性参数计算。通过对含有不同类型孔隙组合碳酸盐岩储层模型的弹性模量进行计算与分析,明确不同孔隙对岩石弹性参数的影响特征,模拟分析结果与实际资料认识一致。  相似文献   

合成淀粉磷酸单酯影响因素的探讨     

邹丽霞  毛志深 《华东地质学院学报》1999,22(3):255-259

以木薯淀粉为原料,探讨了应用于造纸行业中具有一定取工的淀粉磷酸单酯合成的最佳工艺条件。  相似文献   

TROUBLING FIELDS: THE OPIUM POPPY IN EGYPT     

JOSEPH J. HOBBS 《Geographical review》1998,88(1):64-85

ABSTRACT. Probably domesticated in Asia Minor, the opium poppy (Papaver somniferum) may have reached Egypt by 1500 b.c.e. Egyptian opium was important historically for medicinal uses, but increasing recreational use led to eradication efforts by the early twentieth century. With the closure of Lebanon's Bekáa Valley as a source of raw opium, poppy cultivation began in the Sinai Peninsula after 1990. Unemployment attracts bedouin men to this dangerous occupation. A heroin epidemic in Egypt is attributed to them, but their very modest opium production suggests wrongly so. A package of development activities with emphasis on backcountry tourism is proposed as an alternative to poppy farming.  相似文献   

叠前反演在LHK地区烃类检测中的应用     

杨海长  李智  徐建永  周玉 《物探与化探》2011,35(5):666-670,688

针对LHK地区目的层砂泥岩纵波阻抗叠置和AVO异常不明显以及储层地质条件复杂的特点,应用叠前弹性阻抗反演技术体系对该地区油气层的分布做出预测。其关键步骤包括:流体替换模型分析与弹性参数交会分析相结合的敏感参数筛选,不同角道集地震数据体的子波估算和精细标定,弹性参数的反演计算。反演得到的拉梅系数乘以密度体与纵波阻抗体交汇的结果,反映了油气层分布特征,预测结果已被钻井证实。  相似文献   

锌在生物磷灰石中的晶体化学研究进展     

程潇  王长秋  王卉 《岩石矿物学杂志》2019,38(6):871-880

Zn在生物磷灰石中的晶体化学行为不同于在地质体中,传统的磷灰石类质同像替代理论对生物磷灰石中的Ca位替换并不完全适用。为了解释生物磷灰石中Zn的出现,本文对已知的生物磷灰石中Zn的存在情况、Zn对Ca的替代机制以及Zn替代对生物磷灰石的影响等内容进行了综述,并就Zn在生物磷灰石中的晶体化学研究对人体肿瘤诊疗的启示作用进行了简单的讨论。理论和实验均表明Zn可以进入生物磷灰石晶格,占据有Ca缺陷的磷灰石晶格中的Ca2位空缺,使局部结构整体收缩。Zn的掺入对生物磷灰石的晶粒尺寸、结晶度、晶胞参数等均会产生较大的影响。当Zn被固定在人体肿瘤伴有的病理性钙化晶格中时,其可能对周围组织及体液中的Zn含量产生影响,进而影响人体内Zn的新陈代谢。  相似文献   

基于Fisher判别分析法的岩溶塌陷预测     

姜春露  姜振泉 《西安地质学院学报》2012,(1):91-95

为了更准确地预测岩溶塌陷,基于Fisher判别分析法,首先选择内聚力、内摩擦角、覆盖层厚度、覆盖层厚度减高水位埋深、覆盖层厚度减低水位埋深5个最主要的影响因素作为判别因子;接着以桂林市20组岩溶塌陷案例为学习样本进行计算,建立相应的Fisher线性判别函数;然后利用回代估计法对上述20纽样本的预测结果进行逐一检验,其正确率为100％;随后将上述预测结果与前人运用逐步判别、神经网络判别等方法得到的结果进行比较分析,认为Fisher判别分析法具有不需进行模型和参数的选择以及不受人为因素的影响等优点;最后将建立的Fisher线性判别函数用于另外的10组实际案例进行预测分析,预测结果与实际情况完全吻合。结果表明：用Fisher判别分析法进行岩溶塌陷预测,简易方便,正确率高,实用性好;该方法是岩溶塌陷预测的一种新方法。  相似文献