Grain size distribution of quartz isolated from Chinese loess/paleosol

Grain size distribution of bulk loess-paleosol and quartz chemically extracted from the loess/paleosol shows that mean size of the bulk samples is always finer than that of the quartz. The original aeolian depositions have been modified to various degrees by post-depositional weathering and pedogenic processes. The grain size distribution of the isolated quartz should be close to that of the primary aeolian sediment because the chemical pretreatment excludes secondary produced minerals. Therefore, the grain size of the quartz may be considered to more clearly reflect the variations of winter monsoon intensity.     

石羊河古终端湖泊沉积物粒度特征与沉积环境初探

利用石羊河古终端湖泊野麻湖剖面沉积物的粒度资料,分析了粒度组成、粒度参数、概率累积曲线等粒度特征,并探讨了古终端湖泊的沉积环境．结果表明石羊河古终端湖曾经是一个稳定的湖泊环境,大约在距今４０００多年前演变成为浅湖沼环境,现在已完全干涸．野麻湖剖面记录的数层快速风成沉积代表了周期性的沙尘暴事件．     

鄱阳湖松门山岛砂质沉积颗粒表面特征及环境指示意义

沉积物沉积环境的判别对于沉积物物源的分析、古地理重建、古环境和古气候的恢复均具有重要的意义。通过研究发现鄱阳湖松门山岛沉积颗粒表面具有丰富的特征,主要是:贝壳状断口、V形撞击坑、撞击沟、碟形撞击坑与新月形撞击坑等。利用扫描电镜对鄱阳湖松门山岛的样品进行了研究,发现鄱阳湖松门山岛的水下砂体样品普遍可见贝壳状断口、V形撞击坑与撞击沟等,说明该类样品为水成环境;沙丘样品普遍可见标准的碟形撞击坑与新月形撞击坑等,说明为风成环境;处于水下砂体和沙丘过渡带之间的样品上述现象几乎均存在,说明这些沉积物经过风成和水成两种环境的共同改造。分析水成和风成环境下的石英颗粒的不同特征,对这些特征利用线测法进行统计分析,发现不同环境下石英颗粒的特征不仅可以定性判别,还可以半定量区分:在水成环境下的样品撞击沟所占的比值高,通常大于30%,而在风成环境中的样品碟形坑所占的比值高,通常大于40%。这一发现对该地区的沉积环境分析有指导作用,并且对于该地区沉积微相划分具有一定意义。     

塔克拉玛干沙漠高大沙垄区垄间地沿主风向连续分布新月形沙丘表面沙粒粒度特征

以塔克拉玛干沙漠高大沙垄区垄间地防沙治沙工程下风向沿主风向连续分布的4个新月形沙丘为研究对象,研究了沙丘表面不同部位表层沙粒粒度特征,明确防沙治沙工程对沙丘表面沙粒粒度的影响,揭示沙丘表面沙粒粒度空间分布规律.主要结论：防沙治沙工程对于风沙环境的影响是显著的,表现为在防沙治沙工程影响区范围内沙丘表层沙粒明显细化.本文的相关研究结果将为阐明类似人为扰动条件下沙丘表面气流场和沙粒运移规律提供基础数据.     

消失模铸造水基涂料的研制

涂料是消失模铸造最关键的辅助材料之一。为降低消失模铸造涂料的成本，研制了水基消失模涂料。文中采用石英粉为耐火骨料，石英粉共有3种粒度分布。所有涂料用碾轮式混砂机制成膏状涂料，在搅拌机中加入适量水搅拌成液体涂料，然后测其性能。研制出的涂料，配方为：石英粉100％，膨润土4％，白乳胶2．5％，羧甲基纤维素钠（CMC）0．5％，以及其它附加物，其中石英粉要求粒度分布相对集中。该涂料成本低且具有优良的工艺性能，特别适用于球墨铸铁件的消失模铸造生产。     

国内外海岸风成砂粒度参数特征的比较与分析

利用278个国外海岸沙丘砂样数据和136个国内海岸沙丘砂样数据，采用平均粒径、标准偏差、偏度和峰态等指标，对国内外海岸风成砂的粒度参数特征进行了比较和分析。结果表明，我国温带海岸风成砂的粒度参数特征并不完全具备是由分选很好的细砂组成、偏度为对称至正偏、峰态很宽等国外海岸风成砂的粒度参数特征，此与我国海岸风成砂特有的发育条件和演化过程密切相关，其中主要与季风气候特征显、形成时间短风力作用时间有限以及风沙活动空间狭小等有关。     

粤琼海岸沙丘砂石英颗粒的表面结构特征

本文通过对广东和海南海岸沙丘砂石英颗粒的扫描电镜分析,认为其表面结构特征,既具有典型的风成环境特征.又有继承和改造了的海滩砂的特征.风成环境特征的机械撞击痕迹和化学作用痕迹都很明显.     

Discovery of Ordos Cretaceous dune rock and its significance

It has been found that there existed quite a large quantity of dune rocks in the red sandstone of the Zhidan Group of Ordos Cretaceous strata. Their sedimentary structure, grain size and micro-shape of sand grains show an obvious aeolian features. Both the temporal and spatial distribution and sedimentary characteristics of these dune rocks suggest that probably a large sand sea once existed in the Ordos region. It belonged to a subtropical inland trade-wind desert with persistent hot climate and was also an important part of the Cretaceous red desert in China.     

Palaeoenvironmental implication of the Plio-Pleistocene loess deposits in southern Tarim Basin

The sedimentary characteristics, grain-size distribution, geochemical composition and surface characteristics of quartz grains, together with palaeoenvironmental reconnaissance, all point to an aeolian origin for the intercalated siltstone beds in the Plio-Pleistocene Artux and Xiyu Formations along the southern margins of the Tarim Basin, indicating that loess deposition in the region started, at least, in the Early Pliocene. Loess deposition in the southern Tarim Basin was a response to the global deterioration, which might be attributed to the uplift of the Tibetan Plateau.     

La—Cu—O催化剂的结构和形貌

研究了La-Cu-O(La/Cu=1.0)催化剂以及用H_2还原,加痕量Pt 后的催化剂,它们的体相和表面结构,表面铜平均价态.测定了这三个催化剂的形貌、晶拉大小和分布.从而得到以低价态Cu~+,Cu~0为主,并且存在痕量Pt 的No(?)3样品对于CO-O_2,NO-CO 反应活性最高的结论.此外,比表面大、晶粒轮廓不规整、有毛刺、晶粒大小分布范围较宽的催化剂,由于提供了更多的活性中心,而有利于提高反应活性.     

Magnetic granulometry of recent sediments from the Huguang Maar and its implication for provenience

To understand the origin and its climatic implications of the Huguang Maar sediments, we conducted laser grain size analysis and rock mangtic measurement for the recent deposits from the Huguang Maar and for the volcanic rocks of the caldera for comparison. The grain size distributions are dominated by clayey silts for both the bulk sediments and magnetic separates. Acquisition of isothermal remanent magnetization (IRM) and thermal demagnetization of IRM suggest (titano) magnetite as the dominating magnetic mineral in the sediments; high coercivity minerals are not detected. Therefore, the ratio of the susceptibility of anhysteretic remanent magnetization (k _ARM) to the weak field magnetic susceptibility (k), k _ARM/k can be used to estimate the grain size of magnetite. The sediments and volcanic rocks yield values of 13.7 and 11.8 for the k _ARM/_k, respectively, corresponding to grain size values of ～0.03 µm and ～0.05 µm. The magnetic granulometry of lake sediments is distinctive from one of the Chinese loess, in which published data suggest a value of 6.0 for k _ARM/_k, and grain size of ～0.1 µm, but is akin to the nearby volcanic rocks. Although a Loess Plateau source of the lake sediments cannot be fully ruled out, the catchment is most probably the main source. We explain the slightly finer magnetite grain size in sediments than in the volcanic rocks as being disintegrated of particles during erosion and transportation. We conclude that there is no evidence for aeolian input of the Loess Plateau dusts into the Huguang Maar, and the relationship between magnetic parameters of the lake sediments and winter monsoon intensity is probably more complicated than previously thought.     

山东小清河流域黄土的发现及勘探意义

通过钻孔取样、野外考察、粒度分析等方法对山东小清河流域浅层的沉积物特征进行研究。结果表明:小清河流域南部浅层沉积物以泥质粉砂和粉砂质泥为主,富含钙质结核和蜗牛化石等黄土标志物,发育明显的黄土-古土壤沉积旋回;南部粒度特征与青州黄土、北京降尘、西峰黄土等典型的风成沉积物相似,具有中国黄土的典型双峰特征,粒度分布明显粗于北京降尘和西峰黄土,而与邻近的青州黄土相似或较其稍粗,体现近物源的特性;末次冰期时裸露的渤海陆架是研究区黄土的主要物源区,中国东部季风和流域以南的山脉为黄土的形成提供搬运动力和地形条件;流域最北端发育古河道沉积,黄土与古河道间存在一个过渡带,沉积特征的差异和流域内南高北低的地势致使南部潜水面深度远大于北部,最终导致油气地震勘探中北部的地震激发效果明显优于南部。     

应用图像分析法评价花岗岩结构特征

应用图像分析、形态数学及立体学原理,通过岩石薄片,对某地花岗岩某一方向上的结构特征进行定量分析,揭示了花岗岩中几种主要矿物（包括黑云母、白云母、长石及石英）的密度、粒径、形状及空间分布规律．     

东海浪岗山岛屿黄土的粒度组成及风尘特征

通过对东海浪岗山岛屿黄土的系统采样和粒度测试分析，并与其他地方黄土充分对比，讨论了浪岗山第四纪风尘沉积的粒度特征.浪岗山黄土剖面粒度垂向变化不大.小于5 μm颗粒平均含量为24.9%.10~50 μm粒组富集，分布均匀，符合黄土的风成特性.但粗颗粒（>50 μm）含量均超过10%，高于西部黄土的粗颗粒含量.显示该剖面除了接受来自西北内陆的远源风尘物质外，还接受来自沉积区附近的“近源”风尘物质.     

一种自相似二维晶粒长大过程的Monte Carlo仿真

采用Monte Carlo方法仿真了以Weibull尺寸分布为初始组织的正常晶粒长大过程。结果显示，二维正常晶粒长大发展到准稳态长大阶段时，其晶粒尺寸分布不是经典Hillert理论所预测的尺寸分布，而是仍然保持Weibull分布，并且参数基本不发生变化。与国际上同类研究成果的比较进一步表明，不同β值的Weibull分布很适用于表征二维晶粒长大的准稳态晶粒尺寸分布，且表征效果优于文献中的已有工作。     

唐宋时期洛阳城洪水事件的地层沉积记录

通过对隋唐洛阳城定鼎门遗址附近沉积剖面分段采样, 并进行粒度和常量元素分析, 探讨唐宋时期沉积剖面的成因以及洛阳城洪水事件。粒度组分、概率累积曲线以及频率分布曲线表明, 第4, 6, 7层有3次洪水灾害事件发生; SiO₂, Al₂O₃和Fe₂O₃等常量元素含量分析结果表明石英、高岭土以及磁性矿物发生迁移, 反映沉积环境的改变; 第6, 7层底部样品中石英增多, 高岭土以及磁性矿物减少, 印证了粒度分析结果所反映的水灾记录。综合分析表明, 在盛唐时期和中唐时期发生过两次较大规模的水灾事件, 北宋时期发生过一次较为严重的漫洪堆积过程。研究结果与历史文献的记录基本吻合。     

Susceptibility variations of multiple origins of loess from the Ily Basin (NW China)

The magnetic susceptibility of loess from the Ily Basin,northwestern China shows maximum values in S0 paleosols but minimum values in other paleosols,the mechanism of which has been well debated.In this work,systematic magnetic measurements were made on a representative section from Neleke county.The results show that the loess horizons(L1,L2 and L3) have multi-domain magnetite grains of aeolian origin,S0 is characterized by production of pedogenetic ultrafine-grained ferrimagnetic minerals,and the other paleosols(S1,S2,and S3) are characterized by the formation of nonferrimagnetic minerals associated with waterlogging.The correlation between the low concentration of ferrimagnets,high paramagnetic content,high magnetic coercivity remanence,fine ferrimagnetic grain size and intensified pedogenesis suggest two competing processes of pedogenetic enhancement and pedogenetic depletion in the lower paleosols.Pedogenetic depletion dominates and is responsible for the low susceptibility.Changes in magnetic grain size distribution occur during pedogenetic depletion.The susceptibility variations are of multiple origins in the loess of the Ily Basin.Pedogenetic enhancement,pedogenetic depletion,and allochthonous input of magnetic minerals should all be taken into account to explain the variations of magnetic parameters.     

辽宁本溪思山岭铁矿石工艺矿物学

通过化学分析、X射线衍射、光学显微镜、电子探针、MLA等分析手段,对辽宁本溪思山岭铁矿石的化学组成、矿物组成、矿物产出形式、嵌布特征及连生关系等进行了详细研究.结果表明:矿石中的铁主要赋存于磁铁矿和赤铁矿中,主要的脉石矿物为石英和含铁白云石,磁铁矿被赤铁矿交代残余、紧密连生,自形晶粒状铁矿物集合体不规则赋存于石英或白云石矿物中,磁铁矿嵌布粒度微细.此研究结果为该铁矿综合利用提供了重要依据.     

河北平原河流沉积物的结构特征

沉积物的结构特征是分析和对比环境的一种依据。本文根据现代河流的已知沉积微环境中的砂样分析,阐述了河北平原河流沉积物的粒度成分、形态和石英颗粒的表面结构特征。     

三峡水库干流沉积物的粒度分布与矿物组成特征

研究表明:三峡库区干流沉积物的粒度分布和矿物组成都呈现以奉节为界的区域性.库区干流沉积物的岩性为粘土质粉砂,粉砂的平均含量为61%,属于单众数,反映了库区各点的水体流速变化幅度不大.沉积物的主要矿物成分为绿泥石、伊利石和石英,平均占29%,24%、24%;其次为长石、方解石和白云石,占8%、9%、5%;其余为少量的闪石和黄铁矿.与过去相比,库区干流沉积物的矿物组成结构发生很大改变:石英的含量降低将近一半,绿泥石和伊利石的含量大幅度增加.这增加了三峡水库发生富营养化和其它环境问题的潜在风险.