A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radia...A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radiation, and convection. A formula for the calculation of the heat conductivity of a sintering system containing solid phase, liquid phase, and gas phase is given. Due to the continuous movement of the laser beam, a local coordinate system centered on the laser beam is used to simplify the analytical calculation. Assuming that it is approximately a Gaussian laser beam, the heat conduction equation is resolved based on the assumption of the thermal insulating boundary conditions and the fixed thermal physical parameters. The FORTRAN language is employed to compile the program to simulate the temperature field in the direct copper powder sintering process. It shows a good agreement with the preliminary experimental results.[KH3/4D]展开更多
详细分析传统的XML电子病历(Electronic Medical Record,EMR)存储方式.针对传统RMR存储方式修改表结构代价大,系统维护困难、负担加重,不能为XML文档建立索引并加快查询速度,不能充分利用XML数据资源、分解文档通常还会造成细节损失等缺...详细分析传统的XML电子病历(Electronic Medical Record,EMR)存储方式.针对传统RMR存储方式修改表结构代价大,系统维护困难、负担加重,不能为XML文档建立索引并加快查询速度,不能充分利用XML数据资源、分解文档通常还会造成细节损失等缺点,提出一种新的电子病历原生XML存储方式.该方式不仅可以降低系统复杂度,而且结合行业新兴的XML数据操作语言可以方便地将病历中的信息应用于医学信息统计、临床辅助诊断等其他领域,从而拓展电子病历的应用空间.展开更多
文摘A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radiation, and convection. A formula for the calculation of the heat conductivity of a sintering system containing solid phase, liquid phase, and gas phase is given. Due to the continuous movement of the laser beam, a local coordinate system centered on the laser beam is used to simplify the analytical calculation. Assuming that it is approximately a Gaussian laser beam, the heat conduction equation is resolved based on the assumption of the thermal insulating boundary conditions and the fixed thermal physical parameters. The FORTRAN language is employed to compile the program to simulate the temperature field in the direct copper powder sintering process. It shows a good agreement with the preliminary experimental results.[KH3/4D]
文摘详细分析传统的XML电子病历(Electronic Medical Record,EMR)存储方式.针对传统RMR存储方式修改表结构代价大,系统维护困难、负担加重,不能为XML文档建立索引并加快查询速度,不能充分利用XML数据资源、分解文档通常还会造成细节损失等缺点,提出一种新的电子病历原生XML存储方式.该方式不仅可以降低系统复杂度,而且结合行业新兴的XML数据操作语言可以方便地将病历中的信息应用于医学信息统计、临床辅助诊断等其他领域,从而拓展电子病历的应用空间.
