A Study on the Dissolution Kinetics of Basalt—Water Interaction under Different pH Conditions I：Release of Elements and pH Neutralization Effect

Experimental research on the chemical weathering of alkaline-olivine basalt from Huangyi Mountain,Kuandain County,Liaoning.Province and olivine basalt from Dayangke,Mingxi County,Fujian Province has shown that the acidity of the solution tends to become neutral regardless of what the acidity of the starting solution would be during basalt0-water interaction.We call this phenome-non“pH neutralized Effect”.The dissolved species in the solution were determined and unreacted and reacted sample-surface chemical components involved or uninvolved in reaction were analyzed using X-ray photoelectron spectroscopy(XPS).The results revealed two different mechanisms of dissolution of basalt in acidic and basic solutions.     

氮配位的磁性高分子复合微球P（GMA—MMA—AA）／Fe3O4负载钯催化水相Suzuki反应的研究

以可控自由基聚合技术制备的磁性高分子复合微球P（GMA—MMA．AA）／Fe3O4为载体,三乙烯四胺为配体制备了一种新型的负载型钯催化剂。采用透射电镜、振动样品磁强计、x射线光电子能谱仪和x射线衍射分析仪等手段对催化剂进行了表征,并评价了催化剂对水相Suzuki反应的催化活性。结果表明,催化剂的平均粒径为800nm左右,钯在载体表面呈高度分散状态,整个催化剂呈超顺磁性。该催化剂在空气氛围中就能较好的催化水相中芳基卤代物与苯硼酸的Suzuki反应,较高产率且立体选择性地生成取代的联苯产物,反应过程中催化剂可稳定分散于反应体系中,并可在外磁场作用下快速与从体系分离。催化剂重复使用5次后,仍具有较高的活性。     

Experimental Study Assessing the Role of Sedimentary Organic Materials to Control the Redox State of Ground Materials to Control the Redox State of Groundwater: Consumption of Dissolved Oxygen by Humic Acid

Abstract: A total of 189 runs were completed to determine the rate of dissolved oxygen consumption in water by the reaction humic acid at 25°, 45°, and 65°C. Glass vial bottles were used as reaction vessels, and humic aicd and pure water of different intitial O₂ concentration was loaded with humic acid/water weight of 0.008 and 0.009. Vials were opened periodically to measure O₂ concentrations. The pH of the solution fluctuated in the early stages of the experiments and gradually decreased to a constant value. Dissolved oxygen concentration decreased, for example, from initial value of 12 mg/l to 9 mg/l at 25°C, to 5 mg/l at 45°C, and to 2 mg/l at 65°C after the reaction of 500 hours. Analyses of rates suggest that the reaction is first order, and rate constants are 8.42 × 10^-9 at 25°C, 2.22 × 10^-8 at 45°C, and 1.28 × 10^-7 moles m^-2 s^-1 at 65°C.     

Petrology and geochemistry of peridotites from IODP Site U1309 at Atlantis Massif, MAR 30°N: micro- and macro-scale melt penetrations into peridotites

Peridotite samples recovered from IODP Site U1309 at the Atlantis Massif in the Mid-Atlantic Ridge were examined to understand magmatic processes for the oceanic core complex formation. Original peridotite was fragmented, and the limited short peridotite intervals are now surrounded by a huge gabbro body probably formed by late-stage melt injections. Each peridotite interval has various petrographical and geochemical features. A spinel harzburgite in contact with gabbro shows evidence of limited melt penetrations causing gradual compositional change, in terms of trace-element compositions of pyroxenes, as well as modal change near the boundary. Geochemistry of clinopyroxenes with least melt effects indicates that the harzburgite is originally mantle residue formed by partial melting under polybaric conditions, and that such a depleted peridotite is one of the components of the oceanic core complex. Some of plagioclase-bearing peridotites, on the other hand, have more complicated origin. Although their original features were partly overprinted by the injected melt, the original peridotites, both residual and non-residual materials, were possibly derived from the upper mantle. This suggests that the melt injected around an upper mantle region or into mantle material fragments. The injected melt was possibly generated at the ridge-segment center and, then, moved and evolved toward the segment end beneath the oceanic core complex.     

A Review of Magnesium Isotope System in Rivers

In recent years, a series of important progresses have been made in the aspect of magnesium isotopes behavior in weathering processes. These progresses are not only favorable to understand the change of the magnesium isotopic compositions in rivers, but also establish the foundation to further reveal the magnesium isotope geochemical cycle. The magnesium in rivers is both magnesium sink for weathering and magnesium source for the ocean. The Mg isotopic compositions in rivers are dominated by the magnesium sources and Mg isotope fractionations processes. The sources of magnesium in rivers originate mainly from draining rocks, as well as less contribution from the eolian deposition, groundwater, plant debris, and precipitation. The Mg isotope fractionations in rivers are mainly related to precipitation and dissolution of carbonate minerals, silicate mineral hydrolysis, adsorption on mineral or colloidal matter surface, and plant uptake. Generally, the contribution of carbonate minerals dissolution or precipitation is equal to add or reduce magnesium from carbonate endmember, which has a remarkably negative δ²⁶Mg value. Based on the fact that most clay minerals are rich in ²⁶Mg during nature silicate mineral hydrolysis, then it is possible to infer that residual weathering products enrich in ²⁶Mg. However, there is no significant Mg isotope fractionation causing by the adsorption on mineral or colloidal matter surface during river water migration. For the plant uptake, the root prefers to have ²⁶Mg, leading the plant itself rich in heavier Mg isotopic composition. In addition, formation of secondary minerals in rivers could also reflect the changes of chemical parameters in rivers (such as major elements, CO₂ solubility, pH, etc.). Hence, Mg isotopic composition in rivers and associated isotope fractionations are not only the basis for the application of magnesium isotope to trace surface material cycle, but also have important significance for the further understanding the geochemical cycle of magnesium isotopes.     

电阻率法评价膨胀土改良的物化过程

掺石灰、粉煤灰是工程中通常采用的改良膨胀土的方法。土电阻率是土的基本物理指标之一,其变化可反映土的其他物理性质指标的变化。通过掺灰改良膨胀土不同养护龄期下的电阻率测试以及膨胀量、膨胀力及无侧限抗压强度等试验研究,探讨了掺灰改良膨胀土养护过程中的物理化学反应过程。根据养护过程中的电阻率随龄期的变化规律,可将改良膨胀土的物理化学反应过程划分为瞬时反应阶段、主体反应阶段、残余反应阶段和稳定阶段4个不同阶段。针对改良膨胀土质量控制和评价体系中存在的不足,提出了基于电阻率指标的改性膨胀土的质量评价方法,通过试验证实了该方法的有效性和实用性。     

纵横向受荷基桩变形内力的矩阵传递解

针对地基的土体屈服性状,将桩侧土体分为弹性变形区域与塑性变形区域两种情况。假定地基反力系数为3参数的一般形式,同时考虑桩身 效应并计入桩身自重、桩侧摩阻力的影响,根据地基反力法分别建立桩身弹性段和塑性段挠曲线微分方程。在解微分方程的过程中,采用矩阵传递法结合Laplace正逆变换的方法解得桩顶作用轴向力、水平力、弯矩时桩身内力和变形的矩阵传递解,并用Fortran语言编制了相应计算程序。最后将试验数据对上述方法进行验证,结果表明计算值与模型试验的实测值吻合很好,采用文中3参数地基反力法反算所得的地基参数离散性很小,研究结果具有较高的应用价值。     

胶北地区早前寒武纪孔兹岩系的变质演化

在胶北地区出露大面积早前寒武纪孔兹岩,主体岩石为富铝片岩-片麻岩,夹有大理岩等变沉积岩。岩相学、成因矿物学和变质反应性质的研究以及温压条件估算结果表明,研究区孔兹岩系经历了四个阶段的变质演化。早期进变质阶段(M1)的矿物组合为石榴石及其内部的黑云母+斜长石+石英;峰期中-高压麻粒岩相变质阶段(M2)的矿物组合以含蓝晶石的麻粒岩相矿物组合为标志,该阶段最高的温压条件可达760℃、10.0kb;峰后近等温减压麻粒岩相退变质阶段(M3)发生一系列典型减压反应,以新生堇青石的出现为标志,形成了含堇青石的中-低压麻粒岩相矿物组合,稳定的温压条件为750～800℃、4.0～5.4kb;晚期降温退变质阶段(M4)以石榴石转变形成细小黑云母等退变矿物为特征,该阶段的温压条件为550～650℃、4.0kb。孔兹岩系变质演化P-T轨迹具有顺时针型式,先后经历了近等温减压(ITD)和近等压冷却(IBC)的P-T演化,标志着胶北地区早前寒武纪孔兹岩系曾经历了地壳加厚-构造隆升的动力学过程。     

地电化学测量法寻找隐伏金矿的机理及其应用效果

地电化学测量法是在前苏联的地电提取技术基础上进一步发展起来的,以电场形式激发、离子形式记录电化学反应结果的轻便、快速的找矿方法,在探测隐伏矿体方面具有明显优势。通过对该方法的机理和应用效果研究,证明了利用地电化学测量法来寻找隐伏金矿的可行性。