Bi-Sr-Ca-Cu-O体系中可能存在一个新的高T_c超导相

最近,Pb能加强BiSrCaCuO超导体中高T_c相(即2223相,其c(?)37,T_c(?)110K)的出现和掺入sb形成BiPbSbSrCaCuO的T_c可以达到132 K已见报道,我们希望通过其它元素的掺杂取代也出现类似的结果。我们做了大量掺Sb、Ba、In的实验,通过改变

Dy~(3+),Sm~(3+)和Ce~(3+)离子在M_3La_2(BO_3)_4(M=Ca,Sr,Ba)中光谱性质的研究

本文报导了Dy~(3+),Sm~(3+)和Ce~(3+)离子在M_3La_2(BO_3)_4(M=Ca,Sr,Ba)基质中的激发与发射光谱;研究了Dy~(3+)离子黄蓝发射的相强度随基质化合物的组成和结构的不同而呈现的变化规律;讨论了Sm~(3+)离子电荷迁移激发带的能量与基质中近邻阳离子的关系并分析了Sm~(3+)和Eu~(3+)离子4f电子构型对电荷迁移带能量的影响。本文还给出了Dy~(3+),Sm~(3+)和Ce~(3+)离子发光的浓度淬灭值。

Major element, trace element, and Sr, Nd and Pb isotope studies of Cenozoic basalts from the South China Sea

The whole rock K-Ar ages of basalts from the South China Sea basin vary from 3.8 to 7.9 Ma, which suggest that intra-plate volcanism after the cessation of spreading of the South China Sea (SCS) is comparable to that in adjacent regions around the SCS, i.e., Leiqiong Peninsula, northern margin of the SCS, Indochina block, and so on. Based on detailed petrographic studies, we selected many fresh basaltic rocks and measured their major element, trace element, and Sr-Nd-Pb isotope compositions. Geochemical characteristics of major element and trace element show that these basaltic rocks belong to alkali basalt magma series, and are similar to OIB-type basalt. The extent of partial melting of mantle rock in source region is very low, and magma may experience crystallization differentiation and cumulation during the ascent to or storing in the high-level magma chamber. Sr-Nd-Pb isotopic data of these basaltic rocks imply an inhomogeneous mantle below the South China Sea. The nature of magma origin has a two end-member mixing model, one is EM2 (Enriched Mantle 2) which may be originated from mantle plume, the other is DMM (Depleted MORB Mantle). Pb isotopic characteristics show the Dupal anomaly in the South China Sea, and combined with newly found Dupal anomaly at Gakkel ridge in Arctic Ocean, this implies that Dupal anomaly is not only limited to South Hemisphere. In variation diagrams among Sr, Nd and Pb, the origin nature of mantle below the SCS is similar to those below Leiqiong peninsula, northern margin of the SCS and Indochina peninsula, and is different from those below north and northeast China. This study provides geochemical constraints on Hainan mantle plume.

Spatial and temporal variations in pH and total alkalinity at the beginning of the rainy season in the Changjiang Estuary, China

The results of field observation carried out in May 2003 were used to examine pH and total alkalinity behaviors in the Changjiang Estuary. It was showed that PH and total alkalinity took on clear spatial variations in values with the minima in the low salinity region. Like salinity, transect distributions of PH and total alkalinity (TA) in a downriver direction had a sharp gradient each. These gradients appeared in such a sequence that the TA gradient was earlier than salinity and PH gradients, and the salinity gradient was earlier than the PH gradient. These distribution characteristics seemed to be strongly influenced by the mixing process of freshwater and seawater, for both PH and total alkalinity had significant linear relationships with salinity and temperature. For PH, phytoplankton activities also had a significant impact upon its spatial distribution. During a period of 48 h, PH and total alkalinity changed within wide ranges for every layer of the two anchor stations, namely, Stas 13 and 20, which were located at the mixed water mass and seawater mass, respectively. For both Stas 13 and 20, PH and TA fluctuation of every layer could be very wide during a 4 h period. As a whole, the data of the two anchor stations showed that neither variations in salinity and temperature nor phytoplankton activities were the main factors strongly influencing the total alkalinity temporal variability on a small time scale. The data of Sta. 20 implied that both salinity variation and phytoplankton activities had a significant influence on PH temporal variability, but the same conclusion could not be drawn from the data of Sta. 13.

Partial characterization of the hemolytic activity of the nematocyst venom from the jellyfish Cyanea nozakii Kishinouye

Using a recently developed technique to extract jellyfish venom from nematocysts, the present study investigated the hemolytic activity of Cyanea nozakii Kishinouye nematocyst venom on chicken erythrocytes. Venom extract caused a significant concentration-dependent hemolytic effect. The extract could retain its activity at -80 degrees C but was unstable when kept at 4 degrees C and -20 degrees C for 2 days. The hemolytic activity was inhibited by heating within the range of 37-100 degrees C. The extract was active over a pH range of 5.0-8.63 and the pH optima for the extract was 7.8. Incubation of the venom with sphingomyelin specially inhibited hemolytic activity by up to 70%. Cu2+ and Mn2+ greatly reduced the hemolytic activity while Mg2+, Sr2+ and Ba2+ produced a relatively low inhibiting effect on the hemolytic activity. Treatment with Ca2+ induced a concentration-dependent increase in the hemolytic activity. In the presence of 5 mM EDTA, all the hemolytic activity was lost, however, the venom containing 1.5 mM EDTA was stable in the long-term storage. PLA(2) activity was also found in the nematocyst venom of C. nozakii. These characteristics provide us a fundamental knowledge in the C. nozakii nematocyst venom which would benefit future research. (C) 2010 Published by Elsevier Ltd.

流体地球化学：成因、流动和流体-岩石相互作用及塔里木盆地实例研究

Geofluid in sedimentary basins is related to petroleum generation, migration, accumulation and preservation, and is a topic of geological frontier. By integrating the multi-discipline methods of petroleum geochemistry, sedimentology, hydrogeology, petroleum geology and experimental geochemistry, the thesis has carried out experiments of microcline dissolution in solutions with organic acids, crude oil, brines with high total dissolved solids (TDS), and has dealt with Al distribution between the crude oil and the brines after the experiments. Cases for study includes Central Tarim, Hetianhe Gas Field and Kucha forland basin with data containing fluid chemistry and isotopic compositions, thin sections of sandstones and carbonates, homogenization temperatures and salinities of fluid inclusions, isotopic compositions of bulk rock and autigenic minerals. The aims are to elucidate fluid origin and flow in the three areas, effect of hydrocarbon emplacement on diagenesis, and to show occurrence of microbe-mediated, and thermochemical sulfate reduction in the Tarim Basin. Microcline dissolution experiments show that after 100 hour, part of the dissolved Al distributes in the crude oil, and the Al concentrations in the crude oil rise when organic acids are added. The result can be used to explain that most oilfield waters in the Tarim Basin are characterized by less than 3mg/L Al. Crude oil added to the solutions can enhance microcline dissolution, which is also observed in the case - Silurian sandstones with early crude oil emplacement in the Central Tarim. Al and Si have higher concentrations in the experiments of oxalic acid than of acetic acid under the same pH conditions, suggesting that there exist Al-oxalate and Si-oxalate complexes. Presence of acetate can enhance the activity of Ca and Al, but Al concentrations have not been increased significantly due to formation of small Al-acetate complex during the experiments. Relationships between δD and δ~(18)O in conjunction with chemistry of oilfield waters show that the waters are evaporated connate waters, which subsequently mixed with meteoric water, and were influenced by water-rock interactions such as salt dissolution, dolomitization of calcite, albitization of feldspar. In the Hetianhe Gas Field where salt dissolution took place, δD and δ~(18)O values can be used to trace nicely meteoric water recharge area and flow direction, but TDS can not. Part of the waters have high TDS but very light δD and δ~(18)O. When combined with paleo-topography, or fluid potentials, meteoric water is suggested to flow eastward in the Hetianhe Gas Field, which is the same with the Central Tarim. Whist in the Kuche forland basin, meteoric water may have permeated Cambrian-Ordovician strata. Relationship between ~(87)Sr/~(86)Sr and 1/Sr can be used to indicate migration and mixing of brines from carbonate strata (low ~(87)Sr/~(86)Sr ratio but high Sr content), clastic strata (high ~(87)Sr/~(86)Sr ratio but low Sr content) and crystalline basement (high ~(87)Sr/~(86)Sr ratio and heavy δ~(18)O value). Using this approach, it can be found that ~(87)Sr-depleted brine from Ordovician carbonates have migrated up to and mixed with ~(87)Sr-enriched waters from Silurian and Carboniferous sandstones, and that Silurian brines have mixed with meteoric water. In the Kuche forland basin, brines from the Cambrian and Ordovician carbonates have higher ~(87)Sr/~(86)Sr ratios than those from the overlying sandstones, when combined with chemistry, δ~(15)N and ~3He/~4He ratios of the coexisting natural gases, suggesting that the brines were derived from the basement. There exists some debate on the effect of hydrocarbon emplacement on mineral diagenesis. Case-study from Silurian sandstones in the Central Tarim show that quartz has kept overgrowing secondarily when oil saturation was decreased by meteoric water flushing subsequently to hydrocarbon emplacement. Silicon precipitates on the water-wet quartz surface, leading to decreased Si concentration close to the surface. A Si grads can result in Si diffusion, which supplies Si for quartz overgrowth. Hydrocarbon oxidation-sulfate reduction is an important type of organic-inorganic interaction. Not only can it make secondary alteration of hydrocarbons, but generate H_2S and CO_2 gases which can improve reservoir property. Thermochemical sulfate reduction took place at the temperatures more than 125 ℃ to 140 ℃ in the Cambrian-Ordovician carbonates, the products - H_2S and CO_2 gases migrated up to the Silurian, and precipitated as pyrite and calcite, respectively. The pyrite has an average δ~(34)S value close to those of Ordovician seawater and anhydrite, and calcite has δ~(13)C value as low as -21.5‰. In the Hetianhe Gas Field, sulfate reduction bacteria carried by meteoric water flowing eastward may have preferentially depleted ~(12)C of light hydrocarbon gases, and results in heavier δ~(13)C values of the residual hydrocarbon gases and higher molar CO_2 in the natural gases in the west than in the east. Coexisting pyrite has δ~(34)S values as low as -24.9‰.

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.

7.0Ma以来中国黄土粉尘源区的化学风化历史研究-Sr同位素比值的证据

To investigate the changes in the chemical weathering intensity of dust source region in Asia continent, ~(87)Sr/~(86)Sr ratios of acid-washed residues from the loess deposits in China and Tajikistan were analyzed, respectively. The results and conclusions are listed as below. 1. The oscillation of ~(87)Sr/~(86)Sr ratios of acid-insoluble residues in the Chinese Loess Plateau was mainly attributed to the chemical weathering intensity of the source region and the grain size. Counteracted the effect of particle size, the calibrated 87Sr/S6Sr ratio can be used as a proxy for the chemical weathering intensity of the source region. 2. The Sr/ Sr ratios of red clay-loess sequence from the Loess Plateau indicate that the chemical weathering intensity of the dust source region between 7.0 and 2.6 Ma is stronger than that in the Quaternary period. This also suggests a general decline in chemical weathering intensity of the source region from 2.6 Ma to the present. Such pattern is more remarkable since 1.0 Ma BP. 3. The ~(87)Sr/~(86)Sr ratios of the Tajik loess during 0.8-1.8 Ma is much more higher than those from 0.8 Ma to the present. This implies that the chemical weathering intensity of the source region in Central Asia is much stronger during 0.8-1.8 Ma than the period since 0.8 Ma. 4. The record of Sr isotope ratios from both sections shows an accelerating course of aridity of the Asian dust source region over the Quaternary period.

生物壳体Sr／Ca、Mg／Ca、^87Sr／^86Sr比值在恢复古气候、古环境中的应用—以小渡口剖面为例

生物壳体的Sr/Ca、Mg/Ca比值能反映其沉积水体的Sr/Ca、Mg/Ca比值，在一定条件下反映水体的盐度、温度，并分别与宿生水体的盐度、温度呈正比关系。生物壳体的^87Sr/^86Sr比值是恢复盆地古水文条件的一种重要手段。本文以著名的泥河湾盆地小渡口剖面的第28层为实例，力图通过对有孔虫、介形虫、腹足类生物壳体Sr/Ca、Mg/Ca比值与^87Sr/^86Sr比值的对比研究，并结合前人所作的中更新世古地理特征研究，来恢复生物壳体沉积时泥河古湖水的温度、盐度，进而进行古气候、古环境的恢复。研究结果表明：在0.97-0.94Ma间，古泥河湾湖为一陆相湖泊，湖水的温度、盐度变化趋势相吻合，均呈低－高－低的演化特征，可能对应着盆地水体的扩展－退缩－扩展变化。其中，在0.96-0.95Ma间，古泥河湾湖具有较高的温度、盐度特征。生物壳体的Sr/Ca、Mg/Ca比值能反映其沉积水体的Sr/Ca、Mg/Ca比值，在一定条件下反映水体的盐度、温度，并分别与宿生水体的盐度、温度呈正比关系。生物壳体的^87Sr/^86Sr比值是恢复盆地古水文条件的一种重要手段。本文以著名的泥河湾盆地小渡口剖面的第28层为实例，力图通过对有孔虫、介形虫、腹足类生物壳体Sr/Ca、Mg/Ca比值与^87Sr/^86Sr比值的对比研究，并结合前人所作的中更新世古地理特征研究，来恢复生物壳体沉积时泥河古湖水的温度、盐度，进而进行古气候、古环境的恢复。研究结果表明：在0.97-0.94Ma间，古泥河湾湖为一陆相湖泊，湖水的温度、盐度变化趋势相吻合，均呈低－高－低的演化特征，可能对应着盆地水体的扩展－退缩－扩展变化。其中，在0.96-0.95Ma间，古泥河湾湖具有较高的温度、盐度特征。

贵州黄壤地区植物营养元素来源的Sr同位素示踪

为研究植物营养元素来源，对贵州龙里地区黄壤上生长的12种主要植物的部分营养元素含量及Sr同位素特征进行了分析。结果表明：喀斯特地区黄壤上的植物具有高钙含量，营养元素含量由高到低排序为Ca〉K〉Mg；研究区植物的Ca、K、Sr平均含量均高出报道的陆生植物的平均含量，但比贵州地区同样以灰岩为母质发育而来的石灰土上生长的植物低；植物样品的^87Sr／^86Sr同位素比值变化范围在0．70856～0．71145之间。基于锶同位素组成的端员模式计算结果表明，除了苔藓、石松的营养元素主要来源于大气输入外，其他植物的营养元素主要来源于土壤风化.

ICP-MS测定表生水体稀土过程中pH值对酸性膦萃取稀土效率的影响

针对目前最常用的液- 液萃取、ICP- M S 测定法检测表生水体中微量稀土元素方法, 研究了不同pH值条件下, 酸性膦(65%HDEHP 和35%H2M EHP) 自表生水体中萃取稀土元素(REEs) 的回收率。结果表明, 在pH1～ 4 的范围内, 不同性质的水体(湖泊、河流、地下水) 有不同的REEs 回收率。其中湖水在pH 118～ 317 有90% 以上的回收率, 最高回收率为93164%; 河水在pH 211～ 315 范围内有90% 以上的回收率, 最高回收率为95152%; 地下水仅在pH 113～ 115 时回收率超过90% , 最高回收率为97161%。说明在萃取不同表生水体中稀土元素时, 需要调到特定的pH 值才能得到最好的萃取效果。

氢氧化铁胶体/水界面作用与地表水中稀土元素的分异—— pH控制机理的实验研究

实验研究了pH对REE水/粒界面配分行为的影响: 氢氧化铁胶体对REE的作用在胶体形成开始以吸附为主, 然后是解吸, 最后是吸附/解吸趋向平衡; 轻稀土元素(LREE)和重稀土元素(HREE)的吸附率不同, 后者大于前者. 随pH增加, LREE和HREE在氢氧化铁胶体/水之间产生分异, 其配分系数比值(DLREE/DHREE)降低; DREE的分布模式呈现Y的异常(DY/DHo<1)并在低pH条件下呈现明显的四重效应. 实验结果证明自然界中存在REE四重效应. 除pH外, 地表水的化学类型以及离子强度也是控制REE四重效应以及微粒吸附态REE和溶解态REE之间产生分异的重要因素.