Preparation and Thermal Stability of Phosphate System Protection Glasses Doped with Rare Earths

The formation ability and thermal stability of phosphate laser protection glass doped with high Sm2O3 content were discussed. The characteristic temperatures ( Tg, Tc, Tm) were measured by DSC and the crystallization parameter β was calculated. The results show that the forming regions would shrink and tend to closed ellipse with increasing of Sm2O3 content. Increasing of BaO/Al2O3 ratio changes the network structure of rare earth glass and improves the thermal stability finally. However, with the increasing of Sm2O3 content, the β increases firstly and then decreases, and finally the thermal stability also increases firstly and then decreases.

Improving the process forming limit considering forming defects in the transitional region in local loading forming of Ti-alloy rib-web components

The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element（FE） simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology（RSM）.The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components.

Micro thermoplastic forming of a Pd-based metallic glass:theory and applications

Metallic glasses（MGs）are considered as the ideal materials for miniature fabrication because of their excellent micro thermoplastic forming ability in the supercooled liquid region.The understanding and controlling of micro filling process are fundamental for miniature fabrication and their applications,yet presently remain unresolved issues.A universal kinetic equation was proposed to describe the filling kinetics of viscous metallic glass supercooled liquid in micro molds with general cross sectional shapes by using a Pdbased MG as the modeling material and a series of potential applications based on the micro thermoplastic forming of the MG were developed.

Study on the City Form of the Yangtze River Delta Region

The Yangtze River Delta is a rapiddeveloping region in China. With fast economicgrowth, it is facing many environmental problems.This paper discusses the major problems and proposessome strategies for its future development.

Properties and Structures of Bi_2O_3-B_2O_3-TeO_2 Glass

Glass formation range of Bi2O3-B2O3-TeO2 system has been investigated （B2O3 ≤ 40 mol%）. Four glasses with compositions xBi2O3-B2O3-（70-x）TeO2 （x = 40, 50, 60 and 70 tool%） have been prepared by using melt quenching technique. The effect of Bi2O3 content on thermal stability, optical properties and structures of these four Bi2O3-B2O3-TeO2 glasses is systematically investigated by inductive coupled plasma emission spectrometer （ICP）, differential scanning calorimetry （DSC）, Raman spectra and X-ray photoelectron spectroscopy （XPS）. It is found that the density, refractive index and optical basicity increase with increasing Bi2O3. The Raman spectra and XPS spectra show that the glass network is mainly constituted by the [BiO6] octahedron, [TeO4] trigonal bipyramidal, [TeO3] trigonal pyramid, [BO3] trigonal pyramid and [B04] tetrahedron structural units. With increasing Bi2O3, the coordination number around B atom changes from 3 to 4 and [TeO4] units are converted to [TeO3] units. Bi5＋ ions may exist in Bi2O3-B2O3-TeO2 （BBT） system and their amount grows with increasing Bi2O3 content.