原位磁化X射线粉末衍射法测还原铁粉的微观磁致伸缩系数

首次报导X射线粉末衍射法测量铁粉晶胞的磁致伸缩系数。还原铁粉样品原位磁化后 ,铁立方晶胞产生磁致伸缩效应 ,晶胞参数的变化引起衍射峰位置和晶面间距的变化。实验测得铁晶胞λ1 0 0 为 3 .3 3× 10 - 4,此结果表明铁晶胞的微观磁致伸缩系数比棒状、薄膜或粉末压片的系数大约 16倍。对此现象进行了合理的理论解释 ,指出大块材料中的粉末多晶之间具有较大的空隙 ,从而使得宏观磁致伸缩系数变小     

湖南大坳地区云英岩蚀变体型钨锡矿床地质特征及控矿因素

大坳云英岩蚀变体型钨锡矿产于九嶷山复式花岗杂岩体中。钨锡矿体赋存在呈半隐伏产出的蚀变体中，且自下而上重叠分布，具“楼层式”结构的特点；矿体形态、有用组分的分布具有明显的分带性，产状、形态的变化与蚀变体具有一致性。研究认为花岗岩浆的侵位、区域性断裂的多次脉动作用及蚀变作用是区内钨锡矿形成的重要控制因素。     

川西北倒三角形断块东部区域强震带形成机制与地震活动特征

川西北倒三角形断块东部区域地处青藏高原东部边缘地带,地跨川西北高原及其与四川盆地过渡带的高山峡谷区,属我国著名的南北向地震带的中段,因其特定的大地构造环境和强烈的现代地壳构造运动,导致其在强大的近东西向构造应力场的驱动和平卧“A”字型控震构造体系的控制下,沿两侧边界断裂向东强力楔入,于“构造急剧收口带”之西侧形成了一个近SN向地跨三大构造单元的强震带,强震沿该带有规律的往返迁移和重复发生,且地震活动强弱具有较明显的分形特征。     

多相地貌单元场地勘察中基岩与卵砾石、孤石的鉴别

在多相地貌单元场地勘察中，基岩与卵砾石的鉴别难度较大。应利用初步感性认识、钻进状态、岩样特征等多手段对基岩与卵砾石进行判别，以提高判别率。     

多能源矿产共存成藏（矿）机理和富集规律的研究——能源领域研究的新趋势

简要介绍了国内外有关同盆共存的多能源成藏机理、富集规律的研究现状和发展趋势。从国家能源安全和科学研究的现实需要两方面论述了我国开展多能源同盆共存的成藏饥理和富集规律研究的必要性与迫切性，并着重介绍了各种有机能源和铀之间可能存在的某种成生联系及其某种相互依存成藏关系。并指出，多种重要能源矿产共存富集、成藏（矿)及其成因联系和分布规律，已成为一个处于科学前沿、体现多学科交叉和综合的重大基础性科学问题，是今后能源学科的发展趋势和前沿研究的一个重要方向。     

立井变形监测与治理

针 对 我国 部 分 统 配煤 矿 立 井 变形 情 况 ,介 绍 了 立井 破 坏 和 变形 两 种 类 型的 原 因 、预 计 方 法 、监 测 方法 及 治 理方 案,对于 立 井的 变形 监 测与 治理 工 作具 有一 定 的借 鉴意 义 。     

榆林风沙滩区水资源可持续利用对策与建议

本文在对榆林风沙滩区内水资源条件、开发利用现状及存在问题等调查研究资料进行深入分析的基础上,结合国民经济各业未来发展对水资源的需求情况,确定了未来不同水平年的需水量和供水量,并通过供需平衡分析,提出了解决水资源短缺的途径和实现水资源合理开发利用的建议.     

Molecular modeling of the 10-Å phase at subduction zone conditions

Molecular dynamics (MD) modeling of the 10-Å phase, Mg₃Si₄O₁₀(OH)₂·xH₂O, with x=2/3, 1.0 and 2.0 shows complex structural changes with pressure, temperature and water content and provides new insight into the structures and stabilization of these phases under subduction zone conditions. The structure(s) of this phase and its role as a reservoir of water in the mantle have been controversial, and these calculations provide specific predictions that can be tested by in situ diffraction studies. At ambient conditions, the computed structures of talc (x=0) and the 10-Å phases with x=2/3 and 1.0 are stable over the 350-ps period of the MD simulations. Under these conditions, the 10-Å phases show phlogopite-like layer stacking in good agreement with previously published structures based on powder X-ray diffraction data for samples quenched from high-pressure and high-temperature experiments. The calculations show that the 10-Å phase with x=2.0 is unstable at ambient conditions. The computed structures at P=5.5 GPa and T=750 K, well within the known stability field of the 10-Å phase, change significantly with water content, reflecting changing H-bonding configurations. For x=2/3, the layer stacking is talc-like, and for x=1.0, it is phlogopite-like. The calculations show that transformation between these two stackings occurs readily, and that the talc-like stacking for the x=2/3 composition is unlikely to be quenchable to ambient conditions. For x=2.0, the layer stacking at P=5.5 GPa and T=750 K is different than any previously proposed structure for a 10-Å phase. In this structure, the neighboring basal oxygens of adjacent magnesium silicate layers are displaced by b/3 (about 3 Å) resulting in the Si atoms of one siloxane sheet being located above the center of the six-member ring across the interlayer. The water molecules are located 1.2 Å above the center of all six-member rings and accept H-bonds from the OH groups located below the rings. The b/3-displaced structure does not readily transform to either the talc-like or phlogopite-like structure, because neither of these stackings can accommodate two water molecules per formula unit. There is likely to be a compositional discontinuity and phase transition between the b/3-displaced phase and the phase with phlogopite-like stacking. The simulations reported here are the first to use the recently developed CLAYFF force field to calculate mineral structures at elevated pressures and temperatures.     

Method of high-density seismic imaging ex-ploration and application samples

Introduction Now, shallow seismic reflection wave technique has been used extensively in geological ex-plorations of bridge, dam, high building and so on. Since shallow seismic reflection wave tech-nique is often implemented in industrial zone or city with dense population, the background dis-turbance including industrial noise, life noise, etc is very serious. Furthermore, the disturbance of seismic source is also serious due to short array length and offset of the method. In general, shal-lo…     

Investigation of upper crust anisotropy in Ghaen-Birjand region, east-central Iran

IntroductionWhenpropagatingthroughananisotropicmedium,ashearwavesplitsintotwo(quasi)shearwaveswithdifferentpropagationspeedsandpolarizedorthogonally.Owingtotherecentdevel-opmentofseismicobservationsystem,detectionofshearwavessplittingwithverysmalldelaytimesbetweenfasterandslowershearwavesbecameavailableandprovidedpowerfulapproachfordetectionofcrustalanisotropy.Crampin(1978)emphasizedtheroleofalignedmicrocracksasacauseofcrustalanisotropyandpointedoutthatforverticallyalignedmicrocracksthedirecti…