克山病患者与健康人心肌元素含量均值向量比较和对应分析

对18例克山病患者及43例健康人心肌 Ba、Ca、Cd、Co、Cr、Cu、Fe、K、Mg、Mn、Na、P、Ti、Zn 和 Se 含量的两个均值向量进行了比较,结果表明其差异非常显著(P<0.01)。对应分析取最大的两个特征根(其和超过全部特征根之和的85%)绘成二维图,可见:克山病组与健康组分界明确;Se、Zn、Cu、P、Mg 和 K 与健康组关系密切;Ca、Co 和 Na 与克山病组关系密切;Ba、Fe、Mn、Ti、Cd 和 Cr 似乎与两组关系都不密切。

Eu~(2+)和Ce~(3+)在钙钛矿型氟化物中的光谱特征和能量传递

对具d-f和f-f两种跃迁形式的Eu~(2+)和具d-f跃迁特征的Ce~(3+),讨论了它们在ABF_3(A=K~(+),Ba~(2+);B=Li~(+),Mg~(2+),Ca~(2+))中的光谱特征。根据Eu~(2+)、Ce~(3+)在KCaF_3基质中的能级关系,实现了在复合氟化物中Ce~(3+)对Eu~(2+)能量传递,探讨了能量传递机理,并计算了传递量子效率。

地下咸水的化学特征及其在水产养殖中的应用

地下咸水的化学成分与现代海水基本相同，它本身不带病毒，与海水也没有连接的渠道，故海水中的病毒宿主难以侵入，因此，它可以做为海水养殖的一种替代水体，在水产养殖方面有非常广阔的应用前景。本论文首次对用于养殖的胶州地区的地下咸水的形成原因和化学组分特征作了系统阐述。主要的研究内容和研究结果包括：1．咸水入侵和稀释作用是形成该地区地下咸水的主要原因。现代海水和卤水入侵及临近河口区淡水对地下卤水的稀释作用是形成该地区地下咸水的两种主要原因。地质调查结果表明，胶州地区属于地下卤水远景分布区，该地区有不边疆分布的斑块状的地下卤水存在，对地下水的超采造成地下水水位的下降，从而引起咸水入侵。在大沽河河口地区，河流淡水对地下卤水的稀释也是是该区地下咸水形成的一个原因。2．地下咸水的主要化学组分特征 在地下咸水的常量元素分布中，由于地下水流沉积物表面时产生的溶滤作用、离子交换吸附及还原环境下脱硫酸菌的作用使Ca~(2+)/Cl~-、Mg~(2+)/Cl~－、Na~+/Cl~-值与海水中的相应组分的比值相比，有不同程度的升高，SO_4~(2-)/Cl~-明显降低，K~+/Cl~-的值在不同的地区差异较大。通过对几个地区地下水中铁、锰的含量对比，发现其值远高于海水中的含量，可高达每升几毫克，这主要是由于在地下水的还原环境和较低的pH条件下，铁、锰的氧化物较易还原溶出，并讨论了不同地区的Mn/Fe值由于受Fe~(2+)、Mn~(2+)这两种还原产物稳定性的没和铁锰氧化物易被还原的程度不同这两个因素的影响，分别呈现出大于1和小于1的情形。对地下水中微量元素铜、铅、锌、镉的分析表明，这些元素在地下水中的含量与海水中的含量在同一个数量级，差异不显著。以Cl~-为参比因子，从所求得的相关关系来看，锌和铜在地下水中呈较好的保宋性分布，即没有显著的添加或去除行为，铅和镉的保守性较差。地下水中的营养盐分布与海水也有着显著不同，在地下咸水的Eh和pH分布范围内，NH_4~+态氮是地下水中无机氮分布的主要形式，并且由于吸附在粘土中的硅酸盐矿物的转出，地下咸水中的SiO_3~(2-)含量显著偏高。3．Ca~(2+)、Mg~(2+)对对虾生长的影响 利用正交实验证实了Ca~(2+)/Mg~(2+)比值、Ca~(2+)+Mg~(2+)总量以及二者之间的交互作用对对是生长都有显著性影响。对虾生长适宜的Ca~(2+)/Mg~(2+)比值范围是1:1～1:3，对是能在Ca~(2+)/Mg~(2+)比值为1：10的水环境中正常生长，只要有一定的Ca~(2+)+Mg~(2+)总量。较低的Ca~(2+)浓度可能会成为导致对虾存活率降低的原因。

中国对虾(Penaeus chinensis) 与鹰爪虾(Trachypenaeus curvirostris)生殖生物学及早期发育的比较研究

本文主要对中国对虾及鹰的生殖生物学及早期胚胎的发育进行了较为系统的比较研究。在前人工作的基础上对中国对虾及鹰爪虾的精子及精荚形成，精子的超微结构，纳精囊的形态及结构，卵子的激活，受精卵的卵裂等进行了比较研究。使用激光扫描共聚焦显微镜对中国对虾精管的结构及精子的形成过程进行研究。中国对虾的输精管可分为近端、中段、远端输精管及壶腹四部分。输精管壁的本结构相似，分泌细胞的结构及分泌活动有较大的差别。精管自中段膨大部开始管腔逐渐被一隔膜分为大小不等的两部分，较大的腔内充满了很多精子，输精管较小的腔内充满胶体状物质。中国对精子细胞在精巢内产生，在两条输精管内渐发育成熟，经过细胞质的变化并与精子外部进行物质交换，形成顶体、亚顶体、棘突。核的变化则经历了染色质的解凝和核膜的消失，最后形成成熟的精子。对鹰爪虾精子的形成过程及精子的形态结构特征进行，结果表明鹰爪虾精子细胞产生于精巢的生精小管，在输精管内进一步发育，逐渐形成成熟的精子，许多精子在输精管内聚集成团外包胶质膜，形成许多大小不一的精子囊。精子由体 及棘突两部分组成，入海水中不运动。电镜下可见体部包括核区及细胞质区两部分。核区位于精子中部，核内由均质解凝的细胞核，外包一薄层细胞质带。细胞质区比核区略小，末端变尖，细胞质区内含有大量囊泡及膜层体。棘突从体部前端斜向伸出，由许多纤丝平行紧密排列组成，外包质膜。雄虾精子囊中的精子与已交配雌虾纳精囊内的精子在形态结构上没有明显差别。对中国对虾及鹰爪虾的纳精囊及精子的贮存特征进行研究。中国对虾及鹰爪虾的纳精囊都是封闭型纳精囊，中国对虾的纳精囊腔，表面为两个对称的半圆形甲壳版所覆盖，囊内由前向后伸出三个锥状突起。鹰爪纳精表面为前后两个甲壳版所覆盖。纳精囊中部为单一的腔，向后部两侧呈管状延伸，末端膨大形成两个袋状囊，内部贮存精子囊。纳精囊从功能上分为三个部分，即纳精囊中部的开口，交配时为胶体物质所充塞；内部的囊腔为贮存精子的部位；前端的开口为产卵时精释放口。中国对虾及鹰卵子具有相似的激活和卵裂过程。卵子可以不受精子的激活，只受海水刺激即可发生皮层反应；先排出皮质棒或皮质囊泡，形成胶质层，进而释放出皮层颗粒，形成孵化膜。中国对虾的孵化膜在卵子表面形成以后再举起；鹰爪虾的孵化膜远离卵子表面形成，然后进一步举起，鹰爪虾卵周隙较大。发生皮层反应的过程中，减数分裂重新启动，排出第一极体和第二极体。中国对虾与鹰爪虾卵子的皮层反应和减数分裂都可由海水刺激而进行，与受精与否无关，但未受精卵不能分裂或公分裂为大小不等的子细胞。中国对虾与鹰爪虾受精卵都具有原始的螺旋卵裂的特性。对海水中的Mg~(2+)、 Ca~(2+)、 K~+及胰蛋白酶和胰蛋白酶抑制剂对中国对虾卵子激活的影响进行研究。结果表明海水中的Mg~(2+)对中国虾卵子的激活是必须的，Ca~(2+)、 K~+是非必须的，而且它们对受精卵和非受精卵都具有相同的作用。胰蛋白酶（0．1％）在卵子产出后可以破坏胶质层及孵化膜的形成并影响受精卵的正常卵裂。胰蛋白酶抑制剂（0．01％）可以完全抑制卵子的激活及受精，也可以使发生皮层反应的卵子处于停滞状态。卵子产出后30min胰蛋白酶及胰蛋白酶抑制剂对卵子失去作用，表明胶膜及孵化膜完全形成后具有抵抗胰蛋白酶及胰蛋白酶抑制剂的作用。

青藏高原多年冻土区高寒草甸植物群落主要植物化学元素含量特征

分析了青藏高原北麓河地区29种高寒植物15个元素含量的特征。结果表明，这些植物中元素平均含量〉400μg／g的元素有Ca，Mg，Na，K，Fe，10～100μg／g的有Mn，Cr，Zn，Cu，〈10μg／g的有Ni，Co，As,Pb，Cd，Hg；种间同种元素的含量变化规律不统一。相关性分析表明，Cu与Cd，Fe与Cd和Hg，Cr与Ni，Co和Mg极显著正相关，Cr和Ca极显著负相关；聚类分析表明，Na，As元素对本区植物聚类的影响最大，莎草科、禾本科、菊科科内植物元素含量相似。

塞隆骨与虎骨中矿物质元素的比较

目的对比分析国家一类动物药塞隆骨和禁用传统中药材虎骨中的19种矿物质元素的含量.方法骨骼样品经灰化或消解处理后,采用原子吸收光谱法、氢化物原子荧光光谱法、催化极谱法等分析方法测定矿物质元素.结果两种动物骨骼中元素含量差异显著,塞隆骨11种元素高于虎骨,特别是Cu、Zn、Fe、Mn、Se等生命活动必需微量元素塞隆骨极为显著地高于虎骨,而组成骨骼的主要成分Ca、P则为虎骨高于塞隆骨.矿物质元素在头骨、脊梁骨和腿骨中分布非常不平衡,多数元素以头骨中分布最为丰富,而5种常量元素Ca,P,Na,Mg,K的含量为腿骨＞头骨＞脊梁骨.骨骼中主要成分Ca和P的存在形式主要为羟磷灰石Ca10(PO4)6(OH)2.结论塞隆骨骨骼中的矿物质元素与虎骨有可比性,必需微量元素塞隆骨明显优于虎骨.

西江流域环境河水地球化学研究

River is a major component of the global surface water and CO2 cycles. The chemistry of river waters reveals the nature of weathering on a basin-wide scale and helps us understand the exogenic cycles of elements in the continent-river-ocean system. In particular, geochemical investigation of large river gives important information on the biogeochemical cycles of the elements, chemical weathering rates, physical erosion rates and CO2 consumption during the weathering of the rocks within the drainage basin. Its importance has led to a number of detailed geochemical studies on some of the world's large and medium-size river systems. Flowing in the south of China, the Xijiang River is the second largest river in the China with respect to its discharge, after the Yangtze River. Its headwaters drain the YunGui Plateau, where altitude is approximately 2000 meters. Geologically, the carbonate rocks are widely spread in the river drainage basin, which covers an area of about 0.17xl06 km2, i.e., 39% of the whole drainage basin. This study focuses on the chemistry of the Xijiang river system and constitutes the first geochemical investigation into major and trace elements concentrations for both suspended and dissolved loads of this river and its main tributaries, and Sr isotopic composition of the dissolved load is also investigated, in order to determine both chemical weathering and mechanical erosion rates. As compared with the other large rivers of the world, the Xijiang River is characterized by higher major element concentration. The dissolved major cations average 1.17, 0.33, 0.15, and 0.04 mmol I"1 for Ca, Mg, Na, and K, respectively. The total cation concentrations (TZ+) in these rivers vary between 2.2 and 4.4 meq I'1. The high concentration of Ca and Mg, high (Ca+Mg)/(Na+K) ratio (7.9), enormous alkalinity and low dissolved SiO2/HCO3 ratio (0.05) in river waters reveal the importance of carbonate weathering and relatively weak silicate weathering over the river drainage basin. The major elements in river water, such as the alkalis and alkaline-earths, are of different origins: from rain water, silicate weathering, carbonate and evaporite weathering. A mixing model based on mass budget equation is used in this study, which allows the proportions of each element derived from the different source to be calculated. The carbonate weathering is the main source of these elements in the Xijiang drainage basin. The contribution of rainwater, especially for Na, reaches to approximately 50% in some tributaries. Dissolved elemental concentration of the river waters are corrected for rain inputs (mainly oceanic salts), the elemental concentrations derived from the different rock weathering are calculated. As a consequence, silicate, carbonate and total rock weathering rates, together with the consumption rates of atmospheric CO2 by weathering of each of these lithologies have been estimated. They provide specific chemical erosion rates varying between 5.1~17.8 t/km2/yr for silicate, 95.5~157.2 t/km2/yr for carbonate, and 100.6-169.1 t/km2/yr for total rock, respectively. CO2 consumptions by silicate and carbonate weathering approach 13><109and 270.5x10 mol/yr. Mechanical denudation rates deduced from the multi-year average of suspended load concentrations range from 92-874 t/km2/yr. The high denudation rates are mainly attributable to high relief and heavy rainfall, and acid rain is very frequent in the drainage basin, may exceed 50% and the pH value of rainwater may be <4.0, result from SO2 pollution in the atmosphere, results in the dissolution of carbonates and aluminosilicates and hence accelerates the chemical erosion rate. The compositions of minerals and elements of suspended particulate matter are also investigated. The most soluble elements (e.g. Ca, Na, Sr, Mg) are strongly depleted in the suspended phase with respect to upper continent crust, which reflects the high intensity of rock weathering in the drainage basin. Some elements (e.g. Pb, Cu, Co, Cr) show positive anomalies, Pb/Th ratios in suspended matter approach 7 times (Liu Jiang) to 10 times (Nanpan Jiang) the crustal value. The enrichment of these elements in suspended matter reflects the intensity both of anthropogenic pollution and adsorption processes onto particles. The contents of the soluble fraction of rare earth elements (REE) in the river are low, and REE mainly reside in particulate phase. In dissolved phase, the PAAS-normalized distribution patterns show significant HREE enrichment with (La/Yb) SN=0.26~0.94 and Ce depletion with (Ce/Ce*) SN=0.31-0.98, and the most pronounced negative Ce anomalies occur in rivers of high pH. In the suspended phase, the rivers have LREE-enriched patterns relative to PAAS, with (La/Yb) SN=1 -00-1 .40. The results suggest that pH is a major factor controlling both the absolute abundances of REE in solution and the fractionation of REE of dissolved phase. Ce depletion in river waters with high pH values results probably from both preferential removal of Ce onto Fe-Mn oxide coating of particles and CeC^ sedimentation. This process is known to occur in the marine environment and may also occur in high pH rivers. Positive correlations are also observed between La/Yb ratio and DOC, HCO3", PO4", suggesting that colloids and (or) adsorption processes play an important role in the control of these elements.

珠穆朗玛峰东绒布冰川表层雪中的气候和环境记录

Snow chemistry research helps to found the basis of studying ice cores. Samples of fresh snow and snow pits were collected from East Rongbuk Glacier on the north slope of Mt. Qomolangma during October, 2002. Major soluble ions (Na~+, NH_4~+, K~+, Mg~(2+), Ca~(2+), Cl~-, NO_3~- and SO_4~(2-)) andδ~(18)O were detected for analysis. Source analysis showed that major sources contributing to the snow chemistry in Mt. Qomolangma region are remote Asian dust and salt lake dust, sea-salt aerosols from Indian monsoon, local rock-mineral dust, human activities and natural atmospheric procedures. Principal factor analysis indicated that high-concentration group was dominated by continental dust with little oceanic source, indicating continental or local precipitation, while the low group dominated by oceanic aerosols indicated oceanic precipitation. Local mineral dust was a minor a source characterized mainly by Ca~(2+), Mg~(2+) contribution. Ammonia related mainly with continental dusts and nitrogen-circulation processes in the atmosphere, it also had a peculiar source should be seasonal agriculture activities in the south Asia. Nitrate showed bad correlations with other ions for its special chemical characteristics. δ~(18)O and major soluble ions displayed obvious seasonal variations. The summer precipitation had very low ion loadings and relatively lower heavy oxygen isotope from the Indian Ocean with occasionally ion peaks formed by local evaporation. While the winter and spring precipitation had high ion loadings and δ~(18)O value for the great amount of continental dust and evaporated vapors. Frequent fluctuations of δ~(18)O and ion concentration occur during the transitional period, indicating alternated precipitations by various air mass types. Ion concentration in snow from the Qomolangma region is comparable with from the Antactica, representing relatively pure background of atmospheric environment on earth. While the high concentration is close to the glaciers' located near the major sources of Asian dust. Compared with the snow chemistry of South Slope of Mt. Qomolangma, the North Slope has lower sea-salt ion concentration during summer monsoon and higher concentration of all major ions during pre- and post-monsoon period due to it's special geophysical location.

森林流域营养离子循环的锶同位素示踪

大气输入与岩石风化是森林系统K、Na、Ca、Mg等营养离子的主要来源,了解二者的输入比率及转化是研究森林流域内物质循环过程的关键.Sr同位素作为Ca等阳离子的有效"示踪剂",已广泛应用于流域内Ca等阳离子来源及其在系统内循环的研究.本文着重介绍了Sr同位素定量模型的建立及其在森林流域营养离子来源识别和循环通量计算研究中的应用.

贵阳地区雨水化学与Sr同位素地球化学

对贵阳地区22个雨水样品的化学组成和Sr同位素的研究表明，贵阳地区大部分雨水样品的pH值小于5．6(pH=4．53)．雨水中Ca^2+是最主要的阳离子，平均值为57μmol·l^-1(12-164μmol·l^-1)，占阳离子组成的64％-87％；Mg^2+是次要的阳离子，平均值为13μmol·l^-1(5—4μmol·l^-1)，Ca^2+和Mg^2+之和占了阳离子组成的78％-96％；K^+平均值为11μmol·l^-1(2—44μmol·l^-1)；Na^+最少，其平均值为4μmol·l^-1(1—8μmol·l^-1)．SO4^2-是最主要的阴离子，平均值为941μmol·l^-1(34—279μmol·l^-1)，占阴离子组成的28％-94％；NO3^-是次要的阴离子，平均值为48μmol·l^-1(1-252μmol·l^-1)，SO4^2-和NO3^-是决定雨水酸度最主要的离子，SO4^2=和NO3^-之和占阴离子组成的77％-99％；Cl^-最少，平均值为20μmol·l^1(1—128μmol·l^-1)．贵阳地区雨水中Sr的浓度为0．02-O．33μmol·l^-1，^87Sr／^86Sr比值较小(0．707934-0．709080)，非海盐来源的^87Sr／^86Sr比值为0．707820-0．709078．元素比值及Sr同位素组成辨识出贵阳地区雨水溶质主要来源于人为活动，岩石／土壤化学风化次之，海相输入很小或可以忽略不计．

地幔副矿物和硫化物的热（PVT）状态方程研究

矿物PVT状态方程是研究矿物在一定温压条件下的晶胞体积与温度、压力之间的关系，依据这个基本关系，可以了解矿物在高温高压下的密度、弹性、热膨胀等性质。矿物PVT状态方程的研究可以了解矿物在地球深部存在的结构状态，为进一步的理论计算提供基础的数据，其结果也可以与天然和人工地震的地震波反演的结果对比，对地球深部的地质作用过程、物质结构状态和组成进行限制。然而，目前矿物PVT状态方程的研究主要集中在氧化物矿物和上地幔主要矿物（橄榄石和辉石）及其高压相（瓦兹利石、林伍德石、方镁铁矿、Majorite、Mg-Perovskite、Ca-Perovskite）的研究上，对石榴石、尖晶石等地幔常见副矿物和硫化物矿物的PVT状态方程的研究很少。 作者在参与搭建并完善金刚石压腔外加温系统的基础上，利用北京同步辐射X射线衍射实验技术结合金刚石压腔外加温技术对天然铁铝榴石、锰铝榴石、铬尖晶石进行了PVT状态方程的研究，同时对闪锌矿、辰砂、方铅矿、辉钼矿、辉锑矿等硫化物矿物进行了相变及状态方程的研究。结合前人研究成果，讨论了类质同象置换对镁铝－铁铝系列石榴石、锰铝－铁铝系列石榴石、尖晶石和硫化物矿物相变及状态方程的影响。获得了以下研究结果： 1）镁铝－铁铝系列石榴石和锰铝－铁铝系列石榴石的体弹模量都随着铁铝榴石组分的增加而增大。其主要原因是在二价阳离子位置上Fe2+取代了Mg2+、Mn2+。在镁铝－铁铝榴石系列中Mg2+的共价键半径（1.36Å）要大于Fe2+的共价键半径（1.17Å），而Mg2+－O键长（2.270Å）与铁铝榴石中的Fe2+－O（2.299Å）键长基本相当。在锰铝－铁铝榴石系列中， 尽管Mn2+的共价键半径（1.17Å）与铁铝榴石中的Fe2+共价键半径（1.17Å）相等，但是Mn2+－O键长（2.326Å）大于Fe2+－O键长（2.299Å）。较小的键长和共价键半径将会增强离子间的结合力，从而具有较强的抗压缩能力，因此随铁铝榴石组分的增加，镁铝－铁铝榴石系列和锰铝－铁铝榴石系列具有较大的体弹模量。 2）首次获得了铬尖晶石（(Mg0.6766Fe0.2808Na0.0073Ti0.0014)0.9661(Cr1.4874Al0.5367)2.0241O4）的体弹模量的温度导数。结合前人关于其他组分尖晶石的实验结果发现，尖晶石中在四面体位置上发生Fe2+－Mg2+置换对体弹模量的影响要大于在八面体位置上发生Cr3+－Al3+置换对体弹模量的影响。而造成铬尖晶石的体弹模量值比其他组分尖晶石的体弹模量值大的主要原因也是四面体位置上的Fe2+－Mg2+的类质置换。 3）依据获得的尖晶石和石榴石的状态方程计算了不同地幔岩模型（橄榄岩和榴辉岩模型）的密度值在上地幔温压条件下的变化情况。结果表明，在尖晶石二辉橄榄岩模型中尖晶石含量的改变（2％－10％）会引起较大的密度变化（2.2％）；在石榴石二辉橄榄岩（石榴石含量14％－20％）和榴辉岩（石榴石含量37％－45％）模型中石榴石含量的变化几乎未引起其密度值的变化，但石榴石是这两种地幔岩模型中的重要组成矿物。 4）首次获得了辰砂的Cinnabar相、方铅矿的B33相、辉钼矿、辉锑矿体弹模量的温度导数和热膨胀系数。讨论了闪锌矿、辰砂、方铅矿的相变情况。 5）总结了锌的、汞的、铅的硫族化合物发生结构相变的规律。认为造成锌的、汞的、铅的硫族化合物的相变压力随阴离子原子序数的增加（S→Se→Te）而逐渐减小的原因是：元素周期表中相对较大原子序数的原子具有更多的核内电子，引起价电子及导带电子的有效位能相对变弱，引起电离能降低，因此在相对较低的压力下就容易发生结构相变。 6）分析了ZnS中Fe2+替代Zn2+、Sb2S3－Bi2S3、MoS2－WS2以及同族相同结构不同组分的简单硫化物矿物的阴、阳离子对体弹模量值的影响。认为简单硫化物矿物的体弹模量值取决于阴、阳离子的离子半径、电负性以及键长。

贵州喀斯特地区河流的地球化学研究

河水的地球化学研究可以获得有关流域盆地化学风化、气候、上地壳的平均化学和同位素组成以及化学元素在大陆－河流－海洋系统中外生循环过程的重要信息。作为岩溶环境分异强烈的贵州碳酸盐岩区，其地表岩石土壤的风化侵蚀过程，必然具有很大的特殊性，也必然对地表环境系统产生重要的影响。构成该地区生态环境脆弱性和地球化学敏感性的一个重要特性。本论文通过对喀期特地区河流中河水的主量元素、微量元素及其锶同位素组成和分布特征的研究，得出如下主要结论和几点新认识。（1）贵州喀斯特地区河流水化学及地球化学特征主要受控于亚热带湿润气候条件下碳酸盐岩的溶解过程，以高Ca、Mg和高碱度区别亚洲和其它地区河流，其主量元素含量的沿程变化是由流域的岩石和土壤的化学成分、矿物组成及流域的物理、化学风化作用决定的。（2）碳酸盐的溶解－沉淀平衡是制约贵州喀斯特地区河流水化学的重要因素，高Ca、Mg和高碱度导致贵州喀斯特地区河流河水具有沉积性特征，河水相对于CaCO_3处于过饱和状态。（3）贵州喀斯特地区河流大多数河水样品的Sr同位素组成均落在显生宙海水的变化范围内。贵州喀斯特地区河流的Sr同位素组成主要受自然风化过程的影响，河水中Sr的浓度及其同位素组成主要来源于两个端员即具有高的Sr浓度、低的~(86)Sr/~(87)Sr比值的碳酸盐岩端员的风化和具有低的Sr浓度、高的~(86)Sr/~(87)Sr比值的硅酸盐岩端员的风化的混合。Sr同位素组成与元素比值（如Na/Ca、Mg/Ca等）的变化同时辨别出以白云岩为主和以石灰岩为主的溶解端员，贵州喀斯特地区河流的化学组成主要受石灰岩风化作用的控制。（4）通过对贵州喀斯特地区河流河水的主量元素、特别是阴离子（SO~(2-)_4、NO~-_3）和微量元素的含量及其控制因素的研究，表明贵州喀斯特地区河流受污染的程度远低于许多发达国家的河流。贵州乌江水系河流受工业污染的程度高于沅江水系的河流，而沅江水系河流受农业污染的程度高于乌江水系的河流，这与乌江流域的工业比沅江流域的工业发达相一致。（5）对贵州喀斯特地区河流中的一些重金属元素分布的初步研究表明，碳酸盐岩地区河流的高碱度使得河水中重金属离子的停留时产不长，其自然净化能力可能比硅酸盐岩地区的河流高。

Potassium-doped Ni-MgO-ZrO catalysts for dry reforming of methane to synthesis gas

Ni/K-MgO-ZrO catalysts for dry reforming of methane, with a range of Mg/Zr ratios and each containing about 10 wt% Ni, were prepared via Ni nitrate impregnation on MgO-ZrO supports synthesized by co-precipitation using KCO. It was found that a proportion of the potassium of the precipitant remained in the samples and improved the stability of the catalysts in the reaction. It was also shown that reduction of the catalysts at 1,023 K without calcination in air is necessary for stable and high activity; calcination in air at 1,073 K gives a deterioration of the catalytic properties, leading to rapid deactivation during the reaction. The order of the CH conversions of the reduced catalysts after 14 h on stream was as follows: Ni/K-MgZr ~ Ni/K-Mg ≥ Ni/K-MgZr Ni/K-Zr. A catalyst with 0.95 wt% K on MgO-ZrO with a Mg:Zr mole ratio of 5:2 showed the best resistance to deactivation. Experiments in a microbalance system showed that there was only negligible coke deposition on the surface of this sample. This behaviour was attributed to the presence of Ni nanoparticles with a diameter of less than 10 nm located on a MgO/NiO solid solution shell doped by K ions; this in turn covers a core of tetragonal ZrO and/or a MgO/ZrO solid solution. This conclusion was supported by EDS/TEM, XPS, XRD and H chemisorption measurements. © 2013 Springer Science+Business Media New York.

Growth and characterisation of p-type delafossite transparent conducting thin films for heterojunction applications

In the present studies, various copper delafossite materials viz; CuAlO2, CuGaO2, CuFeO2 , CuGa1-xFexO2, CuYO2 and CuCaxY1-xO2 were synthesised by solid state reaction technique. These copper delafossite materials were grown in thin film form by rf magnetron sputtering technique. In general copper delafossites exhibit good optical transparency. The conductivity of the CuYO2 could be improved by Ca doping or by oxygen intercalation by annealing the film in oxygen atmosphere. It has so far been impossible to improve the p-type conductivity of CuGaO2 significantly by doping Mg or Ca on the Ga site. The ptype conductivity is presumed to be due to oxygen doping or Cu Vacancies [6]. Reports in literature show, oxygen intercalation or divalent ion doping on Ga site is not possible for CuGaO2 thin films to improve the p-type conductivity. Sintered powder and crystals of CuFeO2 have been reported as the materials having the highest p-type conductivity [14, 15] among the copper and silver delafossites. However the CuFeO2 films are found to be less transparent in the visible region compared to CuGaO2. Hence in the present work, the solid solution between the CuGaO2 and CuFeO2 was effected by solid state reaction, varying the Fe content. The CuGa1-xFexO2 with Fe content, x=0.5 shows an increase in conductivity by two orders, compared to CuGaO2 but the transparency is only about 50% in the visible region which is less than that of CuGaO2 The synthesis of α−AgGaO2 was carried out by two step process which involves the synthesis of β-AgGaO2 by ion exchange reaction followed by the hydrothermal conversion of the β-AgGaO2 into α-AgGaO2. The trace amount of Ag has been reduced substantially in the two step synthesis compared to the direct hydrothermal synthesis. Thin films of α-AgGaO2 were prepared on silicon and Al2O3 substrates by pulsed laser deposition. These studies indicate the possibility of using this material as p-type material in thin film form for transparent electronics. The room temperature conductivity of α-AgGaO2 was measured as 3.17 x 10-4 Scm-1and the optical band gap was estimated as 4.12 eV. A transparent p-n junction thin film diode on glass substrate was fabricated using p-type α-AgGaO2 and n-ZnO.AgCoO2 thin films with 50% transparency in the visible region were deposited on single crystalline Al2O3 and amorphous silica substrates by RF magnetron sputtering and p type conductivity of AgCoO2 was demonstrated by fabricating transparent p-n junction diode with AgCoO2 as p-side and ZnO: Al as n-side using sputtering. The junction thus obtained was found to be rectifying with a forward to reverse current of about 10 at an applied voltage of 3 V.The present study shows that silver delafossite thin films with p-type conductivity can be used for the fabrication of active devices for transparent electronics applications.

Laboratory simulation of terrestrial meteorite weathering using the Bensour (LL6) ordinary chondrite

Laboratory dissolution experiments using the LL6 ordinary chondrite Bensour demonstrate that meteoritic minerals readily react with distilled water at low temperatures, liberating ions into solution and forming reaction products. Three experiments were performed, all for 68 days and at atmospheric fO(2) but using a range of water/rock ratios and different ternperatures. Experiments I and 2 were batch experiments and undertaken at room temperature, whereas in experiment 3, condensed boiling water was dripped onto meteorite subsamples within a Soxhlet extractor. Solutions from experiment 1 were chemically analyzed at the end of the experiment, whereas aliquots were extracted from experiments 2 and 3 for analysis at regular intervals. In all three experiments, a very significant proportion of the Na, Cl, and K within the Bensour subsamples entered solution, demonstrating that chlorapatite and feldspar were especially susceptible to dissolution. Concentrations of Mg, Al, Si, Ca, and Fe in solution were strongly affected by the precipitation of reaction products and Mg and Ca may also have been removed by sorption. Calculations predict saturation of experimental solutions with respect to Al hydroxides, Fe oxides, and Fe (oxy)hydroxides, which would have frequently been accompanied by hydrous aluminosilicates. Some reaction products were identified and include silica, a Mg-rich silicate, Fe oxides, and Fe (oxy)hydroxides. The implications of these results are that even very short periods of subaerial exposure of ordinary chondrites will lead to dissolution of primary minerals and crystallization of weathering products that are likely to include aluminosilicates and silicates, Mg-Ca carbonates, and sulfates in addition to the ubiquitous Fe oxides and (oxy)hydroxides.