首先比对传统家居设计方式介绍了当前虚拟现实技术的发展情况,关注当前流行的几款虚拟建模软件,阐述了目前UE4软件国外与国内的研究现状。详细介绍了UE4家居建模的流程,包括前置工作与UE4部分两个模块。使用3ds Max 2018软件搭建卧室环...首先比对传统家居设计方式介绍了当前虚拟现实技术的发展情况,关注当前流行的几款虚拟建模软件,阐述了目前UE4软件国外与国内的研究现状。详细介绍了UE4家居建模的流程,包括前置工作与UE4部分两个模块。使用3ds Max 2018软件搭建卧室环境模型,接着对比两种方法将3ds Max 2018生成的模型导入到UE4软件中,着重介绍使用DataSmith插件导出udatasmith文件再导入到UE4软件中的过程,在UE4中对卧室家居环境详细修改、调整光源、物体材质等,最后对日后UE4大型场景的创建与研究进行了展望。展开更多
3,4-Dihydroxy-2-butanone 4-phosphate （DHBP） and GTP are the precursors for riboflavin biosynthesis. In this research, improving the precursor supply for riboflavin production was attempted by overexpressing ribB and...3,4-Dihydroxy-2-butanone 4-phosphate （DHBP） and GTP are the precursors for riboflavin biosynthesis. In this research, improving the precursor supply for riboflavin production was attempted by overexpressing ribB and engineering purine pathway in a riboflavin-producing Escherichia colt strain. Initially, ribB gene was overexpressed to increase the flux from ribulose 5-phosphate （Ru-5-P） to DHBP. Then ndk and grnk genes were overexpressed to enhance GTP supply. Subsequently, a R419L mutation was introduced into purA to reduce the flux from IMP to AMP. Finally, co-overexpression of mutant purF and prs genes further increased riboflavin production. The final strain RF18S produced 387.6 mg riboflavin · L-1 with a yield of 44.8 mg riboflavin per gram glucose in shake-flask fermentations. The final titer and yield were 72.2% and 55.6% higher than those of RF01S, respectively. It was concluded that simultaneously engineering the DHBP synthase and GTP biosynthetic pathway by rational metabolic engineering can efficiently boost riboflavin production in E. coll.展开更多
文摘针对电子试验场内存在试验频次较高、频率冲突严重和空间布局有限等问题,基于三维地理信息及设备模型,建立基于Unreal Engine 4(UE4)平台的综合电子试验场。采用计算电磁学方法和远场分析技术,通过时域有限差分(Finte Difference Time-Domain,FDTD)法、一致性绕射理论(Uniform Theory of Diffraction,UTD)、射线跟踪法等算法优化调整场内设备时、空、频参数。提出了一种改进的FDTD网格划分方法,完成场区设备电磁干扰分析。仿真结果表明,提出的仿真系统有一定的有效性和可靠性。
文摘首先比对传统家居设计方式介绍了当前虚拟现实技术的发展情况,关注当前流行的几款虚拟建模软件,阐述了目前UE4软件国外与国内的研究现状。详细介绍了UE4家居建模的流程,包括前置工作与UE4部分两个模块。使用3ds Max 2018软件搭建卧室环境模型,接着对比两种方法将3ds Max 2018生成的模型导入到UE4软件中,着重介绍使用DataSmith插件导出udatasmith文件再导入到UE4软件中的过程,在UE4中对卧室家居环境详细修改、调整光源、物体材质等,最后对日后UE4大型场景的创建与研究进行了展望。
基金supported by National High-tech R&D Program of China [2012AA02A702, 2012AA022103]
文摘3,4-Dihydroxy-2-butanone 4-phosphate （DHBP） and GTP are the precursors for riboflavin biosynthesis. In this research, improving the precursor supply for riboflavin production was attempted by overexpressing ribB and engineering purine pathway in a riboflavin-producing Escherichia colt strain. Initially, ribB gene was overexpressed to increase the flux from ribulose 5-phosphate （Ru-5-P） to DHBP. Then ndk and grnk genes were overexpressed to enhance GTP supply. Subsequently, a R419L mutation was introduced into purA to reduce the flux from IMP to AMP. Finally, co-overexpression of mutant purF and prs genes further increased riboflavin production. The final strain RF18S produced 387.6 mg riboflavin · L-1 with a yield of 44.8 mg riboflavin per gram glucose in shake-flask fermentations. The final titer and yield were 72.2% and 55.6% higher than those of RF01S, respectively. It was concluded that simultaneously engineering the DHBP synthase and GTP biosynthetic pathway by rational metabolic engineering can efficiently boost riboflavin production in E. coll.
