The structure and processes of nickel induced lateral crystallization are studied.The structure of metal induced lateral crystallization(MILC) is improved by opening a seed window on the buried oxide,which is helpfu t...The structure and processes of nickel induced lateral crystallization are studied.The structure of metal induced lateral crystallization(MILC) is improved by opening a seed window on the buried oxide,which is helpfu to get superior quality of large grain poly Si at low temperature.By optimizing the temperature and time of annealing based on others' pervious work,the large grain poly Si with few defects are obtained,and the typical grain size is 70～80μm.The methods of etching NiSi 2 which is created after the long time annealing are also studied for the first time.Finally,a method is successfully chosen to reduce the possible contamination of Ni and to guarantee the MILC for the submicron VLSI application.展开更多
Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity...Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity of pile foundations provided by the impact of construction of urban tunnels on adjacent pile foundations, under the engineering background of the construction of the # 2 Line of the Guangzhou subway. It is carried out using a fast Lagrangian analysis of a continuum in a 3D numerical code, which is an elastoplastic three-dimensional finite difference model, to simulate the response of piles under the entire process of metro tunneling （deactivation of soil element and activation of the lining）. The adjacent stratum around the tunnel is classified into three regions： Zone Ⅰ （upper adjacent stratum of tunnel）, Zone Ⅱ （45°-upper-lateral adjacent stratum of tunnel） and Zone Ⅲ （lateral adjacent stratum of tunnel）. In each region one typical pile is chosen to be calculated and analyzed in detail. Numerical simulations are mainly conducted at three points of each pile shaft： the side-friction force of the pile, the tip resistance of the pile and the axial loading of the pile. A contrasting analysis has been conducted both in the response of typical piles in different regions and from computer calculated values with site monitoring values. The results of numerical simulations show that the impact on carrying capacity of the piles lies mainly in the impact of construction of urban tunnels on the side-friction forces and the tip resistance of piles. The impact differs considerably among the different strata zones where the pile tips are located. The complicated rules of side-friction force and tip resistance of piles has resulted in complicated rules of pile axial loading thus, in the end, it impacts the carrying capacity of pile-foundations. It is necessary to take positive measures, such as stratum grouting stabilization or foundation underpinning, etc, to deal with the carrying capacity and the settlement of pile-foundations. The results are of value to similar engineering projects.展开更多
文摘The structure and processes of nickel induced lateral crystallization are studied.The structure of metal induced lateral crystallization(MILC) is improved by opening a seed window on the buried oxide,which is helpfu to get superior quality of large grain poly Si at low temperature.By optimizing the temperature and time of annealing based on others' pervious work,the large grain poly Si with few defects are obtained,and the typical grain size is 70～80μm.The methods of etching NiSi 2 which is created after the long time annealing are also studied for the first time.Finally,a method is successfully chosen to reduce the possible contamination of Ni and to guarantee the MILC for the submicron VLSI application.
文摘Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity of pile foundations provided by the impact of construction of urban tunnels on adjacent pile foundations, under the engineering background of the construction of the # 2 Line of the Guangzhou subway. It is carried out using a fast Lagrangian analysis of a continuum in a 3D numerical code, which is an elastoplastic three-dimensional finite difference model, to simulate the response of piles under the entire process of metro tunneling （deactivation of soil element and activation of the lining）. The adjacent stratum around the tunnel is classified into three regions： Zone Ⅰ （upper adjacent stratum of tunnel）, Zone Ⅱ （45°-upper-lateral adjacent stratum of tunnel） and Zone Ⅲ （lateral adjacent stratum of tunnel）. In each region one typical pile is chosen to be calculated and analyzed in detail. Numerical simulations are mainly conducted at three points of each pile shaft： the side-friction force of the pile, the tip resistance of the pile and the axial loading of the pile. A contrasting analysis has been conducted both in the response of typical piles in different regions and from computer calculated values with site monitoring values. The results of numerical simulations show that the impact on carrying capacity of the piles lies mainly in the impact of construction of urban tunnels on the side-friction forces and the tip resistance of piles. The impact differs considerably among the different strata zones where the pile tips are located. The complicated rules of side-friction force and tip resistance of piles has resulted in complicated rules of pile axial loading thus, in the end, it impacts the carrying capacity of pile-foundations. It is necessary to take positive measures, such as stratum grouting stabilization or foundation underpinning, etc, to deal with the carrying capacity and the settlement of pile-foundations. The results are of value to similar engineering projects.
