High-Q microresonators on 4H-silicon-carbide-oninsulator platform for nonlinear photonics

The realization of high-quality (Q) resonators regardless of the underpinning material platforms has been a ceaseless pursuit, because the high-Q resonators pro...     

熔渣中饱和相组元作用浓度的计算

在炉渣结构共存理论的基础上,讨论了当溶渣中出现某组元饱和时的作用浓度计算.研究发现,实测的活度值与计算的作用浓度值之间存在明显的分配关系.考虑此分配比后,可使得计算的作用浓度值和实测的活度值相一致.文中分别讨论了CaO-SiO₂、MnO-SiO₂和MgO-SiO₂渣系的分配比,进而推导了lgL-1/T和析出自由能△G°-T的关系式.     

带圆孔的薄壁管多轴向低周疲劳性能的判据

在40Cr钢制成的带圆孔的薄壁管上进行拉-扭双向的低周疲劳试验,并用弹塑性有限元方法分析试件圆孔区域应力和应变分布。通过对以前的多轴向疲劳准则的分析研究,根据薄壁管拉-扭双向疲劳的试验和理论分析的结果,提出了一个新的多轴向应力疲劳的判据。它可以比较好地预测疲劳起裂寿命和裂纹位置。     

Discussion of the Constitutive Relation on Cyclic Stress-Strain of Engineering Materials

Based on the experimental results and analysis of the cyclic deformation, there is an obvious yield stage on the cyclic stress-strain curve at the stage of small plastic deformation （in room or low temperatures）. This phenomenon is similar to that of monotonic tensile curve case. But for the former the deformation amount at which the yield begins is much smaller than that for the latter. The cyclic stress-strain constitutive relation needs to be further studied according to the actual cyclic stress-strain curve. The conventional constitutive equation σ=Aεⁿ is based on the results only corresponding to the cyclic strengthening stage. It is not appropriate for the stage of the small plastic deformation and the stage of yield.     

多元多相体系化学平衡组成的计算

本文从用计算机代替人工计算多元多相复杂体系化学平衡问题出发,对应用于计算机的Brinkley法,Vcs法及White法作了讨论和比较。指出White法在计算机上实现解决计算多元多相体系化学平衡问题的优点。并介绍了用White法编制的计算多元多相体系化学反应平衡的计算机应用程序的结构及基本工作原理。列出考题。其计算结果与位于联邦德国阿亨大学的冶金热力学数据库、中国科学院化工冶金研究所的无机热化学数据库的计算结果相一致。     

连铸结晶器内钢液弯月面区域速度场的测定

在自行设计的可以实现振动、水冷及拉坯的连铸模拟装置上,分别用低熔点Pb-Sn-Bi合金和硅油模拟钢液和保护渣,对连铸结晶器内弯月面区域液态金属的速度场进行了实验研究.研究结果表明：在结晶器的正滑脱期内,弯月面处的液态金属向靠近结晶器壁的方向运动;在负滑脱期内,其运动方向相反.拉速提高时,正滑脱期内弯月面区域液态金属的速度减小,而负滑脱期内弯月面区域液态金属的速度增大.电磁场对弯月面区域液态金属的运动速度有所抑制.     

Safety modeling and protection for lithium-ion batteries based on artificial neural networks method under mechanical abuse

The safety of lithium-ion batteries under mechanical abuse has become one of the major obstacles affecting the development of electric vehicles.In this paper,th...     

A density functional theory study on the interaction between UO_2~(2+) and the carbamoylphosphoramidic acid ligand for uranium extraction from seawater

Phosphorylurea molecules, which contain both phosphoryl and carbonyl groups, are considered efficient extractants for UO_2~(2+). This study aims to explain the complexation of UO_2~(2+)with carbamoylphosphoramidic acid(CPO), a simple model for phosphorylurea, for ligand design for uranium recovery from seawater using density functional theory calculations, natural bond order analysis,and the quantum theory of atoms in molecules. The results showed that, when CPO acts as a monodentate ligand, the affinity of phosphoryl for UO_2~(2+)is stronger than that of carbonyl, and CPO coordinates with UO_2~(2+)through the phosphoryl oxygen atom. When CPO serves as a bidentate ligand, both the phosphoryl and carbonyl oxygen atoms connect to UO_2~(2+), and the U–O(carbonyl) bond plays a more important role than the U–O(phosphoryl) bond in the interaction between UO_2~(2+)and CPO. This paradox may be caused by the significant charge transfer from the U–O(carbonyl) p bond orbital to the C–N σ antibond orbital of the bidentate CPO. The NH spacer between the phosphoryl and carbonyl groups could ensure the delocalization of the electron system of the molecule. The bidentate binding motif is favored by entropy and opposed by enthalpy, while the monodentate binding motif is favored by enthalpy and opposed by entropy. Ultimately, the bidentate binding motif is more favorable than the monodentate one. As expected, the interaction between UO_2~(2+)and the deprotonated CPO is stronger than that between UO_2~(2+)and the neutral CPO. Comparing the interaction between UO_2~(2+)and CPO with that between UO_2~(2+)and Nphenylcarbamoylphosphoramidic acid(Ph CPO), formed by replacing one hydrogen atom from the terminal nitrogen atom of CPO with a phenyl group, the phenyl substituent at the terminal nitrogen atom of Ph CPO shows a slightly negative effect on the interaction between UO_2~(2+)and Ph CPO.     

Mixing and chemical reaction in an initially non-uniform temperature field

The development of the velocity, temperature and the concentration profiles in the vicinity of the trailing edge is investigated under the boundary layer approximation for an arbitrary initial temperature profile and an arbitrary value of the parameter B for the chemical kinetics.

A series solution is constructed in terms of a system of “universal functions”, from which the initial development of an arbitrary initial temperature profile can be calculated with or without chemical reaction. The first three terms in the series for the temperature have been tabulated previously and are presented here in a diagram.

In the case of no chemical reaction, the analytical results for a given initial temperature distribution predict that the temperature gradient normal to the dividing stream line tends to increase for a limited distance in the downstream direction. This may not be anticipated from the consideration of thermal diffusion alone. Experimental results confirm this qualitative trend. With the three terms in the series solution for the temperature, the agreement between the analytical and the experimental results appears also quite satisfactory.

The analytical results will enable us to calculate the development of the temperature field with chemical reaction. There are as yet no experimental data for comparison.     

面向网络功能虚拟化的高性能负载均衡机制

网络负载均衡器是实现网络功能虚拟化(network function virtualization, NFV)的重要功能组件,通过其准确的业务负载分担,运营商可以灵活、高效地实现业务能力增强和容量扩展.基于DPDK技术框架设计实现了面向NFV的高性能4层网络负载均衡机制及系统HVLB,能够灵活部署运行于主流虚拟化平台.HVLB整体采用软件定义网络(software defined networking, SDN)思想设计,实现调度策略制订和数据转发的有效分离.在转发端基于用户空间实现多核多队列高效数据处理架构,同时保证各处理队列间的数据访问隔离和任务处理均衡;在控制端基于网络链路和计算相结合的综合能力作为NF选择和转发策略的制订依据,在实施业务数据准确分发的基础上保障了网络性能.基于KVM的原型系统实验结果表明：与现有LVS系统相比,HVLB极大地提升了数据包处理与转发性能,并实现了64字节UDP数据包的线速转发.