STUDY ON THE MORPHOLOGY OF POLYVINYL CHLORIDE/POLYSTYRENE BLENDS BY ELECTRON MICROPROBE ANALYSIS

The morphology of polyvinyl chloride/polystyrene (PVC/PS) blend samples with different mass ratios, prepared by means of solution casting and melt mixing, have been successfully examined by electron microprobe analysis (EMP). This experiment was performed in a scanning electron microscope attached to an energy dispersive X-ray analyzer. Differential scanning calorimetry was also used to investigate the phase separation of the blends. The results show that PVC and PS are incompatible and the blends have sea-islands phase structures. Blends prepared via melt mixing have finer phase-dispersion than those prepared via solution casting.

Electron microprobe analysis of Hf and Ti in ultrahigh temperature zircon:Optimized approaches and perspectives

Zircon as a multi-objective typomorphic mineral commonly contains diverse trace elements with specific petrogenetic significances.The Hf abundance in zircon is sensitively indicative of melt fractionation during zircon growth on one hand,and on another,the Ti content is a robust temperature sensor of zircon crystallization and has been effectively u tilized in thermometric estimation.A Hf-Ti negative correlation was previously reported in igneous zircons,and thus a potential Hf thermometry was then speculated.In this work,we performed reliable electron microprobe(EMP)measurements of Hf and Ti in ultrahigh temperature(UHT)zircons from the North China Craton,in optimizing point,line and grid analysis.The EMP contents of Hf and Ti both show a wide range of fluctuation owing to the smaller probe spot,and some of them are higher than the LAICPMS data.The Hf-Ti correlation in UHT zircons displays dual and thus complicated patterns in contrast with the previous consideration,which implicates some other factors controlling the geochemical behaviors of Hf and Ti in zircons.Generally,the estimated Ti temperatures based on the EMP analyses are obviously higher than the LA-ICPMS outcomes,but are well consistent with the actual peak condition of the parent rock.It explains the common underestimation of Ti temperatures in hightemperature metamorphic rocks,by using LA-ICPMS analyses.

Structures of Syn-deformational Granites in the Longquanguan Shear Zone and Their Monazite Electronic Microprobe Dating

The Longquanguan shear zone is an important structural belt in the North China Craton, separating the underlying Fuping complex from the overlying Wutai complex. This shear zone has experienced three episodes of deformation: the first and main episode is a ductile top-to-ESE shear along the gently northwest-west dipping foliations, while the other two episodes are later collapse sliding. Prolonged granites parallel to the shear foliations make one of the main compositions of the Longquanguan shear zone. These granites experienced deformation to form mylonitic rocks when they emplaced during the first episode of deformation. Structural characters of the granites and their contacts to the country rocks indicate that these granites possibly resulted from in-situ partial remelting by shearing, i.e., they are syn-deformational granites. Monazites in these mylonitic granites are magmatic minerals and their crystallization ages may represent ages of the magmatic events, and also the ages for the main deformation of the Longquanguan shear zone. Monazite electronic microprobe dating were carried on two samples of granite, which gives multiple peak ages, among which 1,846 Ma and 1,877 Ma are the main peak ages for the two samples. These ages represent the main deformation of the Longquanguan shear zone, which is consistent with the main regional geological event at about 1,850 Ma caused by the collision between the Eastern and Western Blocks in North China. The good match between the monazite ages and the corresponding regional tectono-thermal events shows the feasibility and reliability of monazite electronic microprobe dating.

Evaluation of Morphology-Stable Critical Size of KNbO3 Crystals

Skeletal form of KNbO3 crystals growing in Li2B4O7 solvent was in-situ observed at 900℃ and it was found that shallow depression started to develop on the surface of KNbO3 crystals when the crystal size exceeded several micron, typically 7 micron. Based on the quantitative criterion derived by Chernov, the estimated critical size of KNbO3 crystals was 1 micron, which was consistent with the experimental measurement. The kinetic coefficients, kcorner and kcr, in the criterion were experimentally obtained in the diffusive-convective and diffusive-advective flow states respectively.

Study on Sulfide-melt Inclusions in Mantle Xenoliths of Xinchang, Zhejiang

In minerals of mantle xenoliths captured within Tertiary alkali-basalt from Xinchang, Zhejiang province, China, many sulfidemelt inclusions were found by the observation of polished thin section. Electron microprobe analysis has been applied to detect the components of sulfide-melt inclusions. The result shows that the sulfide phases of inclusions are mainly pentlandite, and secondarily pyrrho- tite, The molar ratio of Ni to Fe, r_Ni,/r_Fe, of mineral phases in sulfide inclusions is related to olivine contents in host mantle xenoliths. The r_Ni/r_Ni, of sulfides from Xinchang samples has a possitive correlation to r_(Fe+Ni),/r_S. The r_(Fe+Ni),/r_S, becomes higher with the increasing of r_Ni/r_Fe In single sulfide-melt inclusions, r_Ni,/r_Fe, r_(Fe+Ni),/r, and Ni contents increase from the center to edge, reflecting a result of different cooling speed in an inclusion. A comparison between the data from Hannuoba, West Eifel of Germany and Nograd-Gomor of east Europe suggests that the composition of the inclusions is different for each area, which indicated that a regional differentiation of sulfide in mantle fluids.