中红外激光场下阈上电离能谱中的低能结构

强激光诱导原子阈上电离中的低能结构(low-energy structure,LES)是当前强场领域的研究热点,其背后的动力学过程引起了广泛讨论.本文基于半经典模型、SCTS(semi-classical two-step)量子轨道模型和数值求解含时薛定谔方程(time-dependent Schrödinger equation,TDSE)方法,研究了中红外激光场下Xe原子阈上电离中的LES随激光脉冲宽度的依赖.发现LES随脉冲宽度的减小向更低能量方向移动.分析表明:长脉宽条件下,能谱中的多峰结构(LESn)与电子前向散射的阶次n及电子初始横向动量密切相关,而极低能结构(very-low-energy structure,VLES)主要由更高阶次前向散射的电子轨道贡献;少周期脉冲条件下,LES峰值位置随载波包络相位(carrier-envelope phase,CEP)的移动可归因于激光场矢势和离子实库仑势的共同作用随CEP的变化,其中库仑势导致的电子聚束效应是LES峰形成的主要原因.

Fe^（＋24），Fe^（＋25）低能态能级结构及谱线的自发辐射跃迁几率

本文通过采用居间耦合形式下的解析波函数，用相对论微扰法完整地计算了Ｆｅ＋２４低能态（ｎ＝１，２，３）能级结构和相应的谱线自发辐射跃迁几率（Ｆｅ＋２５的数据也同时列出作为对比），所得结果具有较高的精度，且其中涉及Ｆｅ＋２４ｎ＝３能级的数据是首次详细给出的。

Safety and effective developing nuclear power to realize green and low-carbon development

This paper analyzes the role of nuclear power of China's energy structure and industry system. Comparing with other renewable energy the nuclear power chain has very low greenhouse gas emission, so it will play more important role in China's low-carbon economy. The paper also discussed the necessity of nuclear power development to achieve emission reduction, energy structure adjustment, nuclear power safety,environmental protection, enhancement of nuclear power technology, nuclear waste treatment, and disposal, as well as nuclear power plant decommissioning. Based on the safety record and situation of the existing power plants in China, the current status of the development of world nuclear power technology, and the features of the independently designed advanced power plants in China, this paper aims to demonstrate the safety of nuclear power. A nuclear power plant will not cause harm either to the environment and nor to the public according to the real data of radioactivity release, which are obtained from an operational nuclear plant. The development of nuclear power technology can enhance the safety of nuclear power. Further, this paper discusses issues related to the nuclear fuel cycle, the treatment, and disposal strategies of nuclear waste, and the decommissioning of a nuclear power plant, all of which are issues of public concern.

Three-Dimensional Cu-Ni Composite Superamphiphobic Surface via Electrodeposition and Fluorosilane Modification

A superamphiphobic(SAP)surface was fabricated by electrodepositing Cu-Ni micro-nano particles on aluminum substrate and modifying via 1 H,1 H,2 H,2 Hperfluorodecyltrimethoxysilane.Scanning electron microscopy,X-ray diffraction,energydispersive X-ray spectroscopy,and Fourier-transform infrared spectroscopy were employed to investigate the morphology and chemical composition.The results showed that the SAP surface had three-dimensional micro-nano structures and exhibited a maximum water contact angle of 160.0°,oil contact angle of 151.6°,a minimum water slide angle of 0°and oil slide angle of 9°.The mechanical strength and chemical stability of the SAP surface were tested further.The experimental results showed that the SAP surface presented excellent resistance to wear,prominent acid-resistance and alkali-resistance,self-cleaning and anti-fouling properties.

Effect of low temperature aging on microstructure and mechanical properties of super-high strength aluminum alloy

The effects of heat treatment on the microstructure and mechanical properties of two alloys, namely Al-12.2%Zn-2.48%Cu-2.0%Mg-0.15%Zr-0.166%Ag（alloy 1）, and Al-9.99%Zn-1.72%Cu-2.5%Mg- 0.13%Zr （alloy 2） were investigated. The results show that low temperature aging after promotive solution treatment can increase elongation without the loss of strength for the studied alloys. The optimum aging treatment （T6） for alloy 1 and alloy 2 is 100℃/80h and 100℃/48h, respectively. Compared with other heat treatment alloys, alloy 1 and alloy 2 show super-high tensile strength up to 753MPa and 788MPa, remaining 9.3% and 9.7% elongation under T6 condition, respectively. During aging, trace addition of Ag enhances the formations of GP zone and metastable phase, and stabilizes GP zone and metastable phase to a higher temperature. Trace addition of Ag prolongs the aging time of reaching the peak strength and delays over-aging condition of the alloy. However, trace addition of Ag promotes the formation of coarse constituent in the alloy and consumes hardening alloying elements of Zn and Mg. Moreover, the addition of the transition element Zr in 7000 series super-high alloy forms incoherent Al3Zr dispersoid which can serve as nucleation sites for nonuniform precipitation of η phase during aging process. The higher the aging temperature, the greater the tendency for nonuniform precipitation of η phase.

Effect of low temperature thermo-mechanical treatment on microstructures and mechanical properties of TC4 alloy

The effects of low temperature thermo-mechanical treatment （LTTMT） on microstructures and mechanical properties of Ti-6Al-4V （TC4） alloy were studied by optical microscopy （OM）, tensile test, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The experimental results confirm that the strength of TC4 alloy can be improved obviously by LTTMT processing, which combines strain strengthening with aging strengthening. The effect of LTTMT on the alloy depends on the microstructure of the refined and dispersed a＋fl phase on the basis of high dislocation density by pre-deformation below recrystallization temperature. The tensile strength decreases with the increase of pre-deformation reduction. The optimal processing parameters of LTTMT for TC4 alloy are as follows： solution treatment at 900 ℃ for 15 min, pre-deformation in the range of 600-700 ℃ with a reduction of 35%, finally aging at 540 ℃ for 4 h followed by air-cooling.

An active pipe-embedded building envelope for utilizing low-grade energy sources

An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside directly. This kind of structure is named ＂active pipe-embedded building envelope＂ due to dealing with the thermal energy actively inside the structure mass by circulating water. This structure not only deals with thermal energy before the external disturbance becomes cooling/heating load by using the circulating water, but also may use low-grade energy sources such as evaporative cooling, solar energy, and geothermal energy. In the meantime, this structure can also improve the indoor thermal comfort by tempering the internal wall surface temperature variation due to the thermal removal in the mass. This work further presents the thermal performance of this structure under a typical hot summer weather condition by comparing it with that of the conventional external wall/roof with numerical simulation. The results show that this pipe-embedded structure may reduce the external heat transfer significantly and reduce the internal wall surface temperature for improving thermal comfort. This work also presents the effects of the water temperature and the pipe spacing on the heat transfer of this structure. The internal surface heat transfer may reduce by about 2.6 W/mE when the water temperature reduces by 1℃ as far as a brick wall with pipes embedded inside is concerned. When the pipe spacing reduces by 50 mm, the internal wall surface heat flux can also reduce by about 2.3 W/m2.

Two Axes Solar Tracker Based on Solar Maps, Controlled by a Low-Power Microcontroller

There are actually several solutions for two axis solar tracking systems using electromechanical devices, in which a controller detects the Sun apparent position, and controls the position of the structure supporting the panels toward the sun by enabling the engines movement. This work studies the solution of two axis solar tracking system based on solar maps, which can predict the exact apparent position of the Sun, by the latitude＇s location, thereby avoiding the need to use sensors or guidance systems. To accomplish this, it is used a low-power microcontroller, suitably programmed, to control two electric motors to ensure that the panels supporting structure is always oriented towards the sun.

Performance Prediction of Structured Packing Column for Cryogenic Air Separation with Hybrid Model

A detailed investigation of a thermodynamic process in a structured packing distillation column is of great impor- tance in prediction of process efficiency. In order to keep the simplicity of an equilibrium stage model and the accu- racy of a non-equilibrium stage model, a hybrid model is developed to predict the structured packing column in cryogenic air separation. A general solution process for the equilibrium stage model is developed to solve the set of equations of the hybrid model, in which a separation efficiency function is introduced to obtain the resulting tri-diagonal matrix and its solution by the Thomas algorithm. As an example, the algorithm is applied to analyze an upper column of a cryogenic air separation plant with the capacity of 17000 m3·h-1. Rigorous simulations are conducted using Aspen RATEFRAC module to validate the approach. The temperature and composition distributions are in a good agreement with the two methods. The effects of inlet/outlet position and flow rate on the temperature and composition distributions in the column are analyzed. The results demonstrate that the hybrid model and the solution algorithms are effective in analvzin~ the distillation process for a a cryogenic structured packing column.

High performance steels:Initiative and practice

In order to meet the progressive requirement for the performance improvement of steel,the author proposed a novel microstructure featured with multi-phase,meta-stable and multi-scale(so-called as M 3).And then,the new technologies could be developed to process three prototype steels with high performance:the third generation high strength low alloy(HSLA) steels with improved toughness and/or ductility(AKV(40℃)≥200 J and/or A≥20% when Rp0.2 in 800-1000 MPa),the third generation advanced high strength steels(AHSS)(Rm×A≥30 GPa% when Rm from 1000 MPa to 1500 MPa) for automobiles with improved ductility and low cost,and heat resistant martensitic steels with improved creep strength(10000650≥90 MPa).It can be expected that the new technology developed will remarkably improve the safety and reliability of steel products in service for infrastructures,automobiles and fossil power station in the future.