生物降解高分子--聚乳酸的合成

以天然矿石--改性片麻岩为聚合反应的催化剂,通过直接缩聚方法制备了不同分子量的聚乳酸.并应用FTIR,^1H-NMR,DSC等测试手段对两种不同催化剂制备的聚乳酸的结构进行对比研究.同时也研究了反应时间对聚合产物分子量的影响.     

夹皮沟片麻岩岩石化学特征及其地质意义

赋存了夹皮沟金矿区绝大部分金矿的夹皮沟片麻岩主要由ＴＴＧ质斜长片麻岩及其中拉斑玄武岩质暗色包体组成，岩石化学上呈双峰特征和奥长花岗岩系列演化趋势，ＲＥＥ组成上均显示了较大的Ｅｕ正异常，δＥｕ最高可达４．６，相似于西格陵兰等典型太古代高级变质地体中的双峰式片麻岩，与裂谷型太古代绿岩带中的双峰式钙碱性火山岩有着本质的不同．     

片麻岩各向异性力学特性试验研究

岩石的各向异性力学特性对工程安全稳定性具有重要的作用。以片麻岩为研究对象,对垂直层理和平行层理的岩样开展了波速试验、单轴压缩和点荷载试验,分析了其强度特性,讨论了岩样的破坏特征及破裂模式。结果表明:在垂直层理和平行层理两种情况下,片麻岩的波速和强度差别明显,表现出各向异性特征;在垂直层理条件下,片麻岩的点荷载强度指标Is(50)与单轴压缩强度之间的换算系数为21. 25,而平行层理条件下为14. 46;单轴压缩试验中,垂直层理的岩样以拉-剪复合模式破坏,平行层理的岩样以张拉模式破坏;在圆盘形试样的点荷载试验中,试样破裂主要有2块和3块的形式,垂直层理和平行层理加载的破坏形式也存在一定差别。     

Multi-stage evolution of gneiss from North Dabie： evidence from zircon U-Pb chronology

TTG gneiss is a common rock to outcrop in the northern part of the Dabie orogen, a few of which are closely associated with eclogites that experienced the Triassic ultrahigh pressure metamorphism. Although they were thermally metamorphosed by a large-scale magma activity in this region at the Early Cretaceous, it is unclear whether or not they are also affected by the Triassic metamorphism during continental subduction and exhumation. In order to resolve this issue, SHRIMP zircon U-Pb dating was carried out for the host gneiss of eclogites in North Dabie. The results show that cores from the gneiss have an age of 746~.31 Ma, consistent with the protolith ages of granitic gneisses in the Dabie orogen. Zircon overgrowing with different U and Th concentrations give concordant ages of 212~21 and 120~11 Ma, respectively. Th/U ratios of overgrown zircons are both lower than 0.1, suggesting a metamorphic genesis. The present resuits suggest that the gneiss in North Dabie has the similar protolith ages of Neoproterozoic to those granitic gneisses elsewhere in the Dabie orogen, and experienced not only the Triassic metamorphism but also the thermal metamorphism due to the Early Cretaceous magmatism. This provides an important insight into the geodynamic evolution of gneissic rocks in the Dabie orogen.     

Experimental study on dehydration melting of natural biotite-plagioclase gneiss from High Himalayas and implications for Himalayan crust anatexis

Here we present the results of dehydration melting, melt morphology and fluid migration based on the dehydration melting experiments on natural biotite-plagioclase gneiss performed at the pressure of 1.0—1.4 GPa, and at the temperature of 770—1028℃. Experimental results demonstrate that: (ⅰ) most of melt tends to be distributed along mineral boundaries forming “melt film” even the amount of melt is less than 5 vol%; melt connectivity is controlled not only by melt topology but also by melt fraction; (ⅱ) dehydration melting involves a series of subprocesses including subsolidus dehydration reaction, fluid migration, vapor-present melting and vapor-absent melting; (ⅲ) experiments produce peraluminous granitic melt whose composition is similar to that of High Himalayan leucogranites (HHLG) and the residual phase assemblage is Pl+Qz+ Gat+Bio+Opx± Cpx+Ilm/Rut± Kfs and can be comparable with granulites observed in Himalayas. The experiments provide the evidence that biotite-plagioclase gneiss is one of source rocks of HHLG and dehydration melting is an important way to form HHLG and the granulites. Additionally, experimental results provide constraints on determining the P-T conditions of Himalayan crustal anatexis.     

基于颗粒流热固耦合模型的片麻花岗岩损伤特性分析

利用颗粒流离散元程序并基于片麻花岗岩室内物理试验,建立数值热固耦合模型,针对不同温度条件下片麻花岗岩的热损伤演化规律展开分析。结果表明:温度导致片麻花岗岩内部产生初始损伤,且初始损伤随温度升高而累积增加;单轴压缩过程中,温度越高片麻花岗岩损伤越早且越剧烈;温度高于80℃,片麻花岗岩有由脆性向韧性转变的趋势。研究成果可为实际工程中片麻花岗岩的温度损伤评估提供一定的指导意义。     

冀北崇礼红旗营子黑云斜长片麻岩的地质地球化学特征

基于当代红旗营子群是否应该解体这一观点,研究了崇礼红旗营子群中黑云斜长片麻岩的地质地球化学特征。研究表明原岩为泥质沉积岩,其特点为SiO2〉56％,Al2O3〉MgO,Na2O〉K2O,Na2O／（Na2O＋K2O）〉0．5,且其他氧化物与SiO2含量呈现出有规律的变化,随着岩石中SiO：含量的增加,TiO2,AL2O3,FeO,Fe2O3,MgO,CaO,Na2O和K2O呈明显下降趋势。稀土元素总量较低;轻重稀土分离程度较高,LREE／HREE的值为5．16～7．98,La。／Yb。的值为4．28～8．62,轻稀土富集,重稀土平坦分布,稀土配分曲线表现出中等程度的负Eu异常,δEu的值为0．73～0．83。稀土元素Ce基本无异常或略显负异常,表明其形成环境可能为一浅海相或边缘海或被陆地封闭海。     

Structures, kinematics, thermochronology and tectonic evolution of the Ramba gneiss dome in the northern Himalaya

The Ramba gneiss dome, one of the north Himalayan gneiss domes, is composed of three tectono-lithologic units separated by an upper and a lower detachment fault. Low-grade metamorphic Tethyan Himalayan sedimentary sequence formed the upper unit above the brittle upper detachment fault. Mylonitic gneiss and a leucogranite pluton made up the lower unit beneath the ductile lower detachment fault. Mylonitic middle-grade garnet-, staurolite- and andalusite-schist constituted the middle unit between the two faults, which may be that the basal part of the upper unit experienced detachment shear. The Ramba dome underwent three episodes of deformation in its tectonic evolution. The first episode was a top-down-to-north-northwest sliding possibly related to the activity of the south Tibetan detachment system （STDS）. The second episode was the dominant deformation related to a east west extension, which resulted in a unique top-down-to-east kinematics and the major tectonic features of the dome. The third episode was a collapse sliding toward the outsides of the dome. The Ramba gneiss dome is possibly a result of the east-west extension and magmatic diapir. The lower detachment fault is probably the main detachment fault separating the sedimentary sequence from the crystalline basement during the eas-west extension in the dominant deformation episode. The diapir of the leucogranite pluton formed the doming shape of the Ramba gneiss dome. This pluton intruded in the core of the dome in a late stage of the dominant deformation, and its Ar-Ar cooling ages are about 6 Myr. This indicates that the dominant deformation of the dome happened at the same time of the east west extension represented by the nort-south trending rifts throughout the northern Himalaya and southern Tibet. Therefore, the formation of the Ramba gneiss dome should be related to this east west extension.     

Experimental study of the metamorphic reaction involving melt under high temperature and high pressure

HighP-T experiment with natural massive rock sample of garnet biotite plagioclase gneiss indicates that the metamorphic reaction involving melt (reaction between relic mineral phase and melt) is the most important reaction in granulite-facies metamorphism and accompanies anatexis process.