Enhanced Thermal Conductivity and Bending Strength of Graphite Flakes/aluminum Composites Via Graphite Surface Modification

The effect of graphite surface modification on the thermal conductivity(TC) and bending strength of graphite flakes/Al composites(Gf/Al) prepared by gas pressure infiltration were investigated. Al3 Ni and Al4C3 phase may form at the interface in Ni-coated Gf/Al and uncoated Gf/Al composites, respectively, while the Al-Cu compound cannot be observed in Cu-coated Gf/Al composites. The Cu and Ni coatings enhance TC and the bending strength of the composites in the meantime. TC of Cu-coated Gf/Al composites reach 515 Wm^-1·K^-1 with 75 vol% Gf, which are higher than that of Ni-coated Gf/Al. Meanwhile, due to Al3 Ni at the interface, the bending strength of Ni-coated Gf/Al composites are far more than those of the uncoated and Cu-coated Gf/Al with the same content of Gf. The results indicate that metal-coated Gf can effectively improve the interfacial bonding between Gf and Al.

Reconfigurable implementation ARP based on depth threshold in 3D-HEVC

Aiming at the high computational complexity and low efficiency of the advanced residual prediction(ARP)algorithm in 3 dimension high-efficiency video coding(3D-HEVC),the relationship between the depth value and ARP is analyzed.A fast ARP algorithm based on the depth value is proposed,which is implemented on the reconfigurable array processor developed by the project team.It uses a reconfigurable method to realize flexible switching between interview-ARP and tem-poral ARP.Experimental results show that while keeping the coding rate and the peak signal-to-noise ratio(PSNR)basically unchanged,the coding time of the six test sequences is reduced by 16.21%on average compared with HTM16.1.In contrast with non-reconfiguration,the average coding time is reduced by 52%,so the computational efficiency is improved.

Column readout circuit with improved offset mismatch and charge sharing for CMOS image sensor

High linearity and low noise column readout chain are two key factors in CMOS image sensor.However,offset mismatch and charge sharing always exist in the conventional column wise readout implementation,even adopting the technology of correlated double sample.A simple column readout circuit with improved offset mismatch and charge sharing for CMOS image sensor is proposed in this paper.Based on the bottom plate sampling and fixed common level method,this novel design can avoid the offset nonuniformity between the two buffers.Also,the single buffer and switched capacitor technique can effectively suppress the charge sharing caused by the varied operating point.The proposed approach is experimentally verified in a 1024×1024 prototype chip designed and fabricated in 55 nm low power CMOS process.The measurement results show that the linear range is extended by 20%,the readout noise of bright and dark fields is reduced by 40%and 30%respectively,and the improved photo response nonuniformity is up to 1.16%.Finally,a raw sample image taken by the prototype sensor shows the excellent practical performance.

Aero-thermal heating constrained midcourse guidance using state-constrained model predictive static programming method

This paper proposes a multiple-constraints-guaranteed midcourse guidance law for the interception of the hypersonic targets. In traditional midcourse law design, the constraints of the aero-thermal heating are rarely taken into consideration. The performance of the infrared detection system may be degraded and the instability of the flight control system may be induced.To address this problem, a state-constrained model predictive static programming method is introduced such that both terminal constraints(position and angle) and optimal energy consumption can be ensured. As a result, a sub-optimal midcourse guidance,guaranteeing the aforementioned multiple-constraints to be never violated, is synthesized. Simulation results demonstrate the effectiveness of the proposed method.