Superplasticity of fine-grained 7475 Al alloy and a proposed new deformation mechanism

A study has been made to investigate the superplastic deformation mechanisms of 7475 Al alloy in relation to the variation of grain size ranging between 5.5 μm and 13 μm. The strain-rate sensitivity (m) was increased with decreasing grain size in the superplastic deformation regime. Microstructural investigation after tension tests revealed that the dispersoid free zones were produced mostly at the grain boundaries normal to the tensile direction. A new model for describing the deformation behavior of the 7475 Al alloy has been proposed based on the assumption that the grain boundary sliding was accommodated by both diffusional flow and slip. This new model well predicts many aspects of experimental results.     

Electrochemical analysis of the microbiologically influenced corrosion of steels by sulfate-reducing bacteria

The differences between the general corrosion and microbiologically influenced corrosion (MIC) of steels were investigated in terms of its electrochemical behavior and surface phenomena. The corrosion potential of steels in the absence of SRB (sulfate-reducing bacteria) shifted to a negative value with the immersion time. However, the potential of the presence of SRB shifted to a positive value after 30 days' incubation, indicating the growth of SRB biofilms on the test metal specimens and the formation of corrosion products. In addition, the color of a medium inoculated with SRB changed from gray to black. The change in color appeared to be caused by the formation of pyrites (FeS) as a corrosion product, while no significant change in color was observed in a medium without SRB inoculation. Moreover, corrosion rates of various steels tested for MIC were higher compared to those of steels in the absence of SRB. In particular, the corrosion current density of TMCP steels in the presence of SRB was larger than that of other steels. Pitting corrosion was also observed at the surface of all steels in the SRB-inoculated medium. The pitting corrosion likely occurred due to SRB that was associated with the increasing corrosion rates through increasing cathodic reactions, which caused a reduction of sulfate to sulfide as well as the formation of an oxygen concentration cell.     

Discharge characteristics of lead dioxide electrode prepared with cementation lead oxide

Lead acid batteries have had restricted applications because of relatively low energy density below 50Wh/kg. Many efforts have achieved lighter battery components such as separators, connections and containers etc. Thus, the most important problem of the lead acid battery is to improve the low capacity of the active material in the positive electrode. The purpose of this study is to improve the utilization of the active material in the lead dioxide electrode for the lead acid battery through the production of lead oxide with better physicochemical characteristics through cementation. A cementation reaction was performed in 1.0wt.%HCl solution using pure magnesium plate as the reductant. We investigated the utilization of the active material and discharge characteristics of the positive electrode with a current density ranging from 3.4 to 108.8mAcm⁻². As a result, the active material utilization was about 72% at 3.48 mAcm⁻² and increased with decreasing current density. The discharge characteristics according to current density are especially very good at high current density     

RTCr2低铬耐热铸铁的熔炼工艺

介绍了低铬耐热铸铁（RTcr2）的生产过程，用1.5t／h冲天炉和选择化学成分为：ω（cr）1.5％-1.8％，ω（C）3.0％～3.3％，ω（Si）2.0％～2.5％，ω（Mn）≤0.8％，ω（P）、ω（S）≤0.10％的铁液，生产现场严格控制底焦高度、铬铁块度，石灰石加入量等，生产的耐热铸铁完全满足了产品的各项性能要求。     

Laser-assisted machining of compacted graphite iron

Compacted graphite iron (CGI) is a material currently under study for the new generation of engines, including blocks, cylinder liners, and cylinder heads. Its unique graphite structure yields desirable high strength, but makes it difficult to machine, thus resulting in a machining cost. Laser-assisted machining (LAM) is adopted to improve its machinability and hence machining economics. The machinability of CGI is studied by varying depth of cut, feed, and material removal temperature and then evaluating resultant cutting forces, specific cutting energy, surface roughness, and tool wear. At a material removal temperature of 400 °C and a feed of 0.150 mm/rev at a cutting speed of 1.7 m/s, it is shown that tool life is 60% greater than conventional conditions at a feed of 0.100 mm/rev. Surface roughness is improved 5% as compared to conventional machining at a feed of 0.150 mm/rev. CGI microstructure evaluated post machining by sectioning and polishing shows no change. An economic analysis shows that LAM can offer an approximately 20% cost savings for the machining of an engine cylinder liner.     

A timing controller embedded driver IC with 3.24‐Gbps eDP interface for chip‐on‐glass TFT‐LCD applications

This paper presents a timing controller embedded driver (TED) IC with 3.24‐Gbps embedded display port (eDP), which is implemented using a 45‐nm high‐voltage CMOS process for the chip‐on‐glass (COG) TFT‐LCD applications. The proposed TED‐IC employs the input offset calibration scheme, the zero‐adjustable equalizer, and the phase locked loop‐based bang‐bang clock and data recovery to enhance the maximum data rate. Also, the proposed TED‐IC provides efficient power management by supporting advanced link power management feature of eDP standard v1.4. Additionally, the smart charge sharing is proposed to reduce the dynamic power consumption of output buffers. Measured result demonstrates the maximum data rate of 3.24 Gbps from a 1.1 V supply voltage with a 7.9‐inch QXGA 60‐Hz COG‐LCD prototype panel and 44% power saving from the display system.     

Rendering of HDR images to improve brightness discrimination

The impression of quality of images can be enhanced on a high dynamic range (HDR) displays. Generally, a conventional 8‐bit image can be processed to an HDR image by inverse tone mapping operators. Among the operators, brightness discrimination mapping by applying brightness adaptation model attempted to mimic the human visual system. In this paper, we use a brightness adaptation model to derive a brightness discrimination mapping algorithm for HDR displays. The proposed algorithm maximizes a function, which represents the local and global brightness discrimination range by exploiting characteristics of the human visual system. Enhancement of details is verified by visualizing HDR images from dark to bright regions. Improvement of dynamic range is quantified by measuring increased discrimination ratio.     

Mbius-invariant curve and surface energies and their applications

Curvature-based surface energies are frequently used in mathematics, physics, thin plate and shell engineering, and membrane chemistry and biology studies. Invariance under rotations and shifts makes curvature-based energies very attractive for modeling various phenomena. In computer-aided geometric design, the Willmore surfaces and the so-called minimum variation surfaces （MVS） are widely used for shape modeling purposes. The Willmore surfaces are invariant w.r.t conformal transformations （Mbius or conformal invariance）, and studied thoroughly in differential geometry and related disciplines. In contrast, the minimum variation surfaces are not conformal invariant. In this paper, we suggest a simple modification of the minimum variation energy and demonstrate that the resulting modified MVS enjoy Mbius invariance （so we call them conformal-invariant MVS or, shortly, CI-MVS）. We also study connections of CI-MVS with the cyclides of Dupin. In addition, we consider several other conformal-invariant curve and surface energies involving curvatures and curvature derivatives. In particular, we show how filtering with a conformal-invariant curve energy can be used for detecting salient subsets of the principal curvature extremum curves used by Hosaka and co-workers for shape quality inspection purposes.