湖南湘谭锰矿次生氧化带中天然锰钾矿晶胞参数的修正

应用Rietveld -DBW 941 1和Pirum程序对湘潭锰矿次生氧化带中天然锰钾矿的X射线粉晶衍射数据进行了晶胞参数的修正 ,首次给出其晶胞参数 :a0 =0 .9974nm ,b0 =0 .2 86 3nm ,c0 =0 .9693nm ,β =91 .467° ,V =2 76 .66× 1 0 - 3nm3,同时指出天然锰钾矿晶体结构精细化的难点在于其呈隐晶质集合体的特征导致衍射峰宽化、背底高和不对称     

Discovery of Stolzite in China and Refinement of Its Crystal Structure

Although stolzite was discovered in Yaogangxian, Hunan Province, China, in 1948, no formal report about this mineral has been published. Recently its crystal structure has been refined by means of the Rietveld method. The cell dimensions of the mineral are: a=b= 0.544503(3) nm, c= 1.20495(1)nm and α=β=γ=90° . The X, Y and Z coordinates of the atom O refined by the authors are 0.2637, 0.1137 and 0.0706, respectively. The length of the W-O bond is 0.17826 nm and the angle of the O-W-O bound are 123° and 103° ,respectively.     

Foundation pit dewatering optimization design based on GMW-2005 and LGR technique

The slope instability and uneven settlement caused by the foundation pit dewatering pose a great threat to the project and surrounding environment.Thus,it is necessary to carry out optimization design of the foundation pit dewatering project.To solve this problem,this paper introduces the simulation-optimization method and establishes the groundwater model based on MODFLOW-2005.The local grid refinement(LGR)technique is employed to achieve the refinement of dewatering area.Under the premise of construction safety,the minimum cost of the project is set as the objective function to solve the optimization problem of foundation pit engineering with GWM-2005.The results show that the optimization with GWM-2005 will be more accurate combined with the LGR model,but the improvement of the optimization is not obvious.It is necessary to choose a suitable local refinement model considering the engineering requirement.     

Pedogenically degenerated illite and chlorite lattices aid to palaeoclimatic reconstruction for chronologically constrained(8-130 ka) loess-palaeosols of Dilpur Formation,Kashmir,India

Chronologically well-constrained loess-palaeosols(recorded glacial and inter-glacial climate) revealed pedogenesis induced ionic substitutions,caused end-member compositional deviations in illite and chlorite,linked to widespread climatic changes occurred during Late Pleistocene.Further,micro-level climatic resolution is yet to be resolved.Thus,layer-wise X-ray diffraction analyses of clay separates,followed by Rietveld refinement revealed varied cell parameters and interatomic distances.Obtained values for detrital and pedogenic illite and chlorite when plotted against stratigraphic succession show notable changes in the crystallographic axes.The illite lattices associated with inadequately pedogenized palaeosols have been altered into illite/smectite mixed layers,but,the chlorite lattices represent expansion of a-,b-and contraction of c-axes with much greater amount of distortions,suggestive of warm-humid and acidic environment.The detrital 48,44 and 83,74 bonded illite and chlorite with2 sub-types each,when pedogenized retained 48,44 and 34;and 83 and 74 bonds(in their neo-formed 3 and 2 sub-types),respectively.The Al-O bond shows expansion,but,unchanged Si-O and decreased Si-K and K-O bonds show loss of Al and retention of Si and K ions in the illite lattices.The illite with 32 atoms and 48 bonds represent contraction of K-O,Si-K,Al-O and Si-O bonds caused bond reinforcement;however,loss of Al~(3+)reflects all-out illite alteration.Owing to Al-O and K-O bond expansion,major K~+ and Al~(3+) ionic loss occurred during the LGM,however,further ionic loss depends upon the magnitude of the loess-palaeosol weathering that they have suffered.The clilate sensitive Fe,Mg and Al ionic losses for Fe-O,Mg-O and Al_(11)-O_9 bond length expansions were recognized in the chlorite lattices.Such ionic losses are common,but,complete distortion is attributed to Al,Si,Fe and Mg ionic losses,followed by weakening of Al-O,Si-O,Fe-O and Mg-O bonds.Though,Si-O_4 and Fe_1-O_4 bonds,and Si and Fe_(1 st) ions remain intact.Thus,three major glacial episodes of ～5 ka each occurred under alkaline environment,but,intervened by two successive cycles of 55 ka each,encompassing three alternate warm and cold climatic sub-cycles of 12-15 ka.But,the coldness increases with each warm-cold sub-cycle that attained the glacial maxima.Further,these events correlate well with the deep-sea records of the North Atlantic(MIS-1 to MIS-5 e) and CLP loess-palaeosols(～127 ka).     

中国西南地区GPS大气水汽转换系数模型精化研究

利用中国西南地区19个探空站2011～2014年数据,通过积分法计算大气水汽转换系数K。采用2011～2013年的K值对Emardson模型进行精化,分别构建西南地区不顾及和顾及高程因子的K值模型Emardson-I和Emardson-H。利用2014年积分计算的K值检验这两种模型的预报精度,结果表明:1)相对于Emardson-I模型,Emardson-H模型表现出更高的K值预报精度和更好的适应性;2)在高海拔地区,Emardson-H模型预报精度明显优于Emardson-I模型,表明高程因子是影响高海拔地区K值计算的重要因素。将两种新模型用于拉萨站GPS大气水汽反演,Emardson-H模型表现出更优的反演精度,两种模型的反演精度均优于2 mm。     

Structure and Mössbauer spectroscopy of barbosalite Fe2+Fe3+ 2 (PO4)2(OH)2 between 80 K and 300 K

Natural barbosalite Fe²⁺Fe³⁺ ₂ (PO₄)₂(OH)₂ from Bull Moose Mine, South Dakota, U.S.A., having ideal composition, was investigated with single crystal X-ray diffraction techniques, Mössbauer spectroscopy and SQUID magnetometry to redetermine crystal structure, valence state of iron and evolution of ⁵⁷Fe Mössbauer parameter and to propose the magnetic structure at low temperatures. At 298?K the title compound is monoclinic, space group P2₁/n, a _o ?= 7.3294(16)?Å, b _o ?=?7.4921(17)?Å, c _o ?=?7.4148 (18)?Å, β?=?118.43(3)°, Z?=?2. No crystallographic phase transition was observed between 298?K and 110?K. Slight discontinuities in the temperature dependence of lattice parameters and bond angles in the range between 150?K and 180?K are ascribed to the magnetic phase transition of the title compound. At 298?K the Mössbauer spectrum of the barbosalite shows two paramagnetic components, typical for Fe²⁺ and Fe³⁺ in octahedral coordination; the area ratio Fe³⁺/Fe²⁺ is exactly two, corresponding to the ideal value. Both the Fe²⁺ and the Fe³⁺ sublattice order magnetically below 173?K and exhibit a fully developed magnetic pattern at 160?K. The electric field gradient at the Fe²⁺ site is distorted from axial symmetry with the direction of the magnetic field nearly perpendicular to V_zz, the main component of the electric field gradient. The temperature dependent magnetic susceptibility exhibits strong antiferromagnetic ordering within the corner-sharing Fe³⁺-chains parallel to [101], whereas ferromagnetic coupling is assumed within the face-sharing [1?1?0] and [?1?1?0] Fe³⁺-Fe²⁺-Fe³⁺ trimer, connecting the Fe³⁺-chains to each other.     

一种改进的自适应蝴蝶细分算法及其在三维地质建模中的应用

改进的蝴蝶细分算法因过原始控制点的特性,在三维地学建模中广泛应用,但细分后的巨大数据量使其必须采用自适应细分的思路。该文在分析常规自适应蝴蝶细分算法缺陷及其产生原因的基础上,提出根据各个细分块体的实际情况动态扩大细分区域的新自适应细分算法。在保持低数据量的条件下,大大改善了细分后整体光滑程度和对细节的表达效果。     

适用于不同尺度区域的Klobuchar-like电离层模型

导航定位中运用最广泛的电离层修正模型是Klobuchar模型,但经典的Klobuchar模型不能满足日益增长的导航定位精度的需求,因此不同的精化模型被提出。本文利用GIMs分析了夜间电离层随地方时的变化和电离层电子总含量随纬度的变化情况,在对各种适用范围较广的模型精化方案进行归纳总结的基础上,提出了一种适用于不同尺度区域的Klobuchar-like模型,并利用不同太阳活动时期不同季节的GIMs建立了适用于单站、大区域和全球的Klobuchar-like模型、14参数Klobuchar模型和8参数Klobuchar模型。Klobuchar-like模型单站、区域、全球的修正率分别达到了92.96%、91.55%、72.67%,均高于14参数、8参数Klobuchar模型和GPS Klobuchar模型,表明了该模型的有效性与实用性。     

天津市静海区暴雨灾害风险精细化评估

根据天津市静海区18个乡镇2009—2018年逐时降水量,以及社会经济、地理地形、水利设施等数据,结合历史受灾信息,分别对静海区的暴雨致灾因子危险性、孕灾环境敏感性、承灾体易损性及防灾减灾能力进行分析,采用GIS技术和统计方法多因子叠加,综合得出静海地区暴雨灾害风险精细化评估和区划。研究发现,静海区北部区域以及南部中旺镇及其周边风险较高,而静海地区中部的风险较低;暴雨灾害高风险区主要分布在致灾因子敏感性、承灾体易损性较高而防灾减灾能力较低的静海镇和梁头镇及其周边,应加强防灾减灾设施建设。     

新型测绘技术在轨道交通智慧建造中的应用

随着建筑业"十三五"规划收尾和"十四五"规划的启动,轨道交通智慧建造的水平大大提升。智慧建造能够辅助项目进行精细化智慧化管控,可以在一定程度上使得城市交通建设满足我国社会发展的现状和要求,但是在轨道交通智慧建造过程中出现的问题和需要考虑的因素较多。因此,本文在轨道交通智慧建造现有体系中引入新型测绘技术,分析其在应用中的主要特点和功能,重构了智慧建造架构体系,深入探讨了新型测绘技术带来的智慧变革,提升了轨道交通建设的整体水平和应用深度。