The effect of eutectic structure and long period stacking ordered (LPSO) structure on the corrosion resistance of Mg 95.5 Gd 3.5 Zn 1 alloy has been investigated. The eutectic structure and LPSO phase were obtained by different heat treatments and their corrosion behavior and microstructures were examined by immersion test, electrochemical measurement, and SEM. It is suggested that the Mg 95.5 Gd 3.5 Zn 1 alloy containing LPSO phase has a better corrosion resistance than that without LPSO phase. This is due to the smaller accelerating corrosion effect, which is caused by the contact between a-Mg and LPSO phase. Figure 4. Cross-sectional SEM images of corroded surface after immersed in 0.17 M NaCl solution for 18 h: (a) aged Mg 95.5 Gd 3.5 Zn 1 alloy with LPSO phase and (b) as-cast Mg 95.5 Gd 3.5 Zn 1 alloy with eutectic structureFigure 5. Polarization curves of the as-cast and aged Mg 95.5 Gd 3.5 Zn 1 alloys in 0.17 M NaCl solution at room temperature www.matcorr.com

The Modbus TCP/IP has been a standard industry communication protocol and widely utilized for establishing sensor-cloud platforms on the Internet. However, numerous existing data acquisition systems built on traditional single-chip microcontrollers without sufficient resources cannot support it, because the complete Modbus TCP/IP protocol always works dependent on a full operating system which occupies abundant hardware resources. Hence, a compact Modbus TCP/IP protocol is proposed in this work to make it run efficiently and stably even on a resource-limited hardware platform. Firstly, the Modbus TCP/IP protocol stack is analyzed and the refined protocol suite is rebuilt by streamlining the typical TCP/IP suite. Then, specific implementation of every hierarchical layer is respectively presented in detail according to the protocol structure. Besides, the compact protocol is implemented in a traditional microprocessor to validate the feasibility of the scheme. Finally, the performance of the proposed scenario is assessed. The experimental results demonstrate that message packets match the frame format of Modbus TCP/IP protocol and the average bandwidth reaches to 1.15 Mbps. The compact protocol operates stably even based on a traditional microcontroller with only 4-kB RAM and 12-MHz system clock, and no communication congestion or frequent packet loss occurs.

When applying phase-only computer-generated hologram (CGH) as a standard model of optical measurement in computer-generated holography for aspheric surface testing, it has the advantage of simplifying optical path configuration and improving the diffraction efficiency of the incoming light. However, errors always exists during the encoding process of fabricating multiphase level CGHs and this kind of errors will be amplified level by level in the measurement. According to the analysis of the encoding error, the error of CGH increases linearly when its quantified period increases. For example, if the quantified period is 32, the maximum of encoding error is 16.46 which can lead wave-front aberration 0.085λ of a secondary parabolic surface with 512×512 sampling pixels. In this article, an optimization method based on deviation of minimum boundary value has been used to eliminate the encoding error of CGH. In the experiment, we use a liquid crystal spatial light modulator to generate CGHs and measure residuals of reconstructed wave-front of a secondary parabolic surface. The measurement results show that average decrease of the RMS values of the residuals is 0.07λ when their periods range from 3 to 6, which indicates the optimization method is effective.