Generation of simultaneous H+ and He+ band EMIC waves in the nightside radiation belt

Science China Technological Sciences - Previous studies have shown that EMIC waves occur preferentially in the afternoon sector of the magnetosphere. Here we report obliquely propagating H+ and He+...     

羰基铁粉表面改性及其热稳定性研究

采用硅烷偶联剂对羰基铁颗粒进行表面改性,研究改性羰基铁粉的热稳定性,利用扫描电镜、红外光谱、差热分析等分析手段,对羰基铁粉表面改性效果和机理进行系统分析。结果表明:经过硅烷偶联剂改性之后的羰基铁粉红外图谱出现了Si—O—Si和Si—O—Fe的特征峰,说明硅烷偶联剂与羰基铁颗粒表面发生化学键合作用;改性后的羰基铁粉与未改性羰基铁粉相比,其分散性和抗氧化能力得到了明显提高。     

可解决深度冲突的3D字幕的添加方法

提出了一种3D字幕的混合插入方法,即插入的字幕既能产生立体效果,又能融入到真实的场景中。将字幕以一定的负视差分别添加到左右视图中,并根据场景的深度情况来确认景物与3D字幕的遮挡关系,解决3D图像中字幕与图像深度混乱的问题,让字幕与场景虚实结合,能达到更真实的立体观看效果。     

Corrosion and irradiation behavior of Fe-based amorphous coating in lead-bismuth eutectic liquids

Lead-bismuth eutectics (LBE) have considerable potential as a candidate material for accelerator-driven sub-critical systems (ADS). However, LBE corrosion and irradiation damage are two urgent challenges remaining to be solved for impellers of primary pumps. In this study, we have explored the possibility of using Fe-based amorphous coatings to overcome LBE corrosion and concurrently to sustain irradiation damage. Specifically, the Fe₅₄Cr₁₈Mo₂Zr₈B₁₈ amorphous coating was prepared by high-velocity oxygen-fuel (HVOF) spraying on 316L steel and exposed to saturated oxygen static LBE for 500 h at 400°C. The coating with high thermal stability (T_g=615°C and T_x=660°C) effectively prevented the substrate steel from being corroded by LBE owing to its unique long-range disordered atomic packing. The coating also exhibited strong irradiation resistance when being subjected to 45 dpa (displacement per atom) Au ion irradiation at room temperature, with no sign of crystallization even at the maximum implantation depth of 300 nm. Consequently, the hardness of the coatings before and after irradiation increased slightly. The current findings shed new insights into understanding corrosion mechanism and irradiation behavior of amorphous solids in LBE and expand the application range of amorphous materials.

     

Environment-friendly energy from all-carbon solar cells based on fullerene-C60

An efficient single layer organic solar cell based on plain buckminsterfulerence (C₆₀) has been fabricated. By inserting a very thin N,N′-bis(naphthalene-1-yl)-N,N′-bis(phenyl)benzidine layer between the indium tin oxide and single C₆₀ active layer, a short-circuit current of 1.98 mA/cm² and an open-circuit voltage of 0.52 V are obtained under 100 mW/cm² AM1.5G simulated illumination. The highest power conversion efficiency of 0.414% based on plain C₆₀ is thus demonstrated, which is the first step to realize an environment-friendly energy source.     

Dynamic anti-windup design for anticipatory activation：enlargement of the domain of attraction

Traditional anti-windup compensators are designed for activation immediately at the occurrence of actuator saturation.Recently,anti-windup compensators were designed for actuation either after the saturation has reached a certain level or in anticipation of its occurrence.In the case of static anti-windup compensators,it has been shown that an anti-windup compensator designed for activation in anticipation of actuator saturation would lead to better performance than those designed for immediate or delayed activation could,both in terms of transient performance and the size of the domain of attraction.More recently,it has been shown that a dynamic anti-windup compensator designed for anticipatory activation would also result in better transient performance than those designed for immediate or delayed activation could.In this paper,we design dynamic anti-windup compensators for the enlargement of the domain of attraction.These compensators are designed respectively for immediate,delayed and anticipatory activation.We will show by simulation that a dynamic anti-windup compensator designed for anticipatory activation would result in a larger domain of attraction than a dynamic anti-windup compensator designed for immediate or delayed activation could.     

Design of multiple anti-windup loops for multiple activations

This paper considers anti-windup design for linear systems subject to actuator saturation.Three anti-windup gains are designed for activations immediately at the occurrence actuator saturation,after the saturation has reached a certain level and in anticipation of the occurrence of saturation,respectively.The design is based on the minimization of L 2 gain from the disturbance to the controlled output of the resulting closed-loop system.Traditional anti-windup scheme involves a single anti-windup loop for immediate activation.A recent innovation is to design a single anti-windup loop for delayed or anticipatory activation,as well as to design two anti-windup gains,one for immediate activation and one for delayed activation.Our design of three anti-windup gains for three different activations is shown through simulation to lead to significant further performance improvement over the previous activation schemes.