Hydrothermal synthesis of Ca doped β-In2S3 for effective dyes degradation

Photocatalytic technology can provide a clean, low-cost and highly efficient path to approach the degradation of azo dyes. Tetragonal β-In₂S₃ possesses plenty of vacancies, furnishing dopants with abundant interspace, and can be used as a potential photocatalyst for dyes degradation. In this work, Ca was doped into β-In₂S₃ via a facile one-pot hydrothermal method, which was mainly doped into the crystalline lattices of β-In₂S₃. Ca doped β-In₂S₃ revealed better photo-degradation of Methyl Orange (MO) than undoped β-In₂S₃. The doped Ca ions narrowed band gap and acted as a charge transfer medium, leading to the wider light absorption range and smaller photogenerated charge transfer resistance, respectively. The optimum preparation condition of Ca doped β-In₂S₃ was determined as holding temperature at 120 °C for 8 h, by which 94.97% of MO was degraded in 20 mins under visible light. The outstanding performance could be owed to the full-grown flaky structure with maximal specific surface area. Based on the experimental results, a possible photocatalytic mechanism for MO degradation over Ca doped β-In₂S₃ was proposed.     

Ta对新β型γ-TiAl基合金板材组织与性能的影响

本文以Ti-42.5Al-2Cr-0.2W与Ti-42.5Al-2Cr-0.2W-3Ta合金板材为研究对象,系统分析了Ta对两种合金的不同状态显微组织及硬度的影响规律与内在的机制变化。结果表明：加工状态下,未含Ta的组织中片层粗大且原始α晶粒较多;含Ta的组织片层细小均匀,再结晶晶粒数量多,原始α晶粒少。热处理状态下,含Ta的组织中片层球化趋势增加,B2相易分解为α2+γ。热处理时间延长,未含Ta的合金组织内的晶团长大速度更快。TEM组织中含Ta的合金板材组织中存在更多的β相以及少量的ω相,不含Ta的组织中β相少且无ω相。此外,硬度分析发现含有Ta的γ-TiAl合金板材硬度值低于不含Ta的合金板材,这与片层细小及β、ω相的数量有关。     

Modified graphite electrode by polyaniline/tourmaline improves the performance of bio-cathode microbial fuel cell

Bio-cathode which uses microorganisms as catalyst can reduce MFC cost and sustain similar power output compared to noble metal catalyst. Thereby, looking for a cathode material which is high conductivity, good biocompatibility and even can stimulate and enhance activity of bio-catalyst is of great interest. In this paper, modified electrode by tourmaline and polyaniline (reactor 3) was used as cathode. The output power density was improved by 492.6% and 192.8% compared to reactor 1 (unmodified cathode) and reactor 2 (cathode modified only by polyaniline) (54 mW m⁻² for reactor 1, 138 mW m⁻² for reactor 2 and 266 mW m⁻² for reactor 3, respectively). When the external resistance was 800Ω, output voltages of reactor 1, 2 and 3 were kept at 0.20 ± 0.005 V, 0.26 ± 0.005 V and 0.37 ± 0.005 V, respectively. Cyclic voltammetry curves showed that reductive current of reactor 3 was higher than those of reactor 1 and 2, indicating that the cathode of reactor 3 had the strongest catalytic activity which was due to that tourmaline could help the interfacial electron transfer, and thereby facilitate the reduction of oxygen at the cathode. Results demonstrated that the tourmaline modified electrode could effectively improve the reduction reaction and enhance the performance of the whole MFC system.     

地震区简支梁桥防落梁装置的设计

文中指出了对地震活动区域的简支梁桥设置防落梁装置的重要性,并介绍了防落梁装置的主要应用型式及其特点、选择方法和注意事项,同时阐述了常用型式—拉索式防落梁装置的设计步骤、具体构造及其在我国的工程应用实例。防落梁装置的设置将为我国桥梁结构在强烈地震作用下的安全提供可靠的保障。     

阵列式震动信号采集同步系统设计

本文针对基于阵列式振动信号采集系统的同步数据获取的需求,在分析系统要求的基础上,提出了实现远距离同步触发的整体方案。并采用自顶向下的设计思想,将系统分为无线收发模块、无线信道模块、加法计数器模块、传感器模块、数字时标模块五个模块,提出了各模块的实现方案。之后对影响系统性能的因素的各模块进行了仿真分析。     

A high speed 1000 fps CMOS image sensor with low noise global shutter pixels

A low read noise 8T global shutter pixel for high speed CMOS image sensor is proposed in this paper.The pixel has a pixel level sample-and-hold circuit and an in-pixel amplifier whose gain is larger than one.Using pixel level sample-and-hold circuit,the KTC noise on FD node can be effectively cancelled by correlated double sampling operation.The in-pixel amplifier with a gain larger than one is employed for reducing the pixel level sample-and-hold capacitors thermal noise and their geometric size.A high speed 1000 fps 256×256 CMOS image sensor based on the pixel is implemented in 0.18μm CMOS process.The chip active area is 5 mm×7 mm with a pixel size of 14μm×14μm.The developed sensor achieves a read noise level as low as 14.8e-while attaining a high fill factor of 40%.The full well capacity can contain 30840e-and the resulting signal dynamic range is 66 dB.     

视觉测量中动态编码点的设计与检测

针对机器视觉动态测量中编码点的使用需求,提出了一种基于频率编码的动态编码点。在测量过程中,动态编码点按照固定的频率闪烁,将编码点的闪烁频率作为编码信息。动态编码点由静态定位区与动态编码区组成,其中,静态定位区用于对动态编码点特征圆的识别与定位,编码点的编码信息储存在动态编码区中。根据动态编码点的结构,设计了编码点的检测与解码算法,实现了动态编码点的快速检测。编码点提取实验结果表明,动态编码点编码方案简便稳定,便于布置,易于检测和识别,满足设计要求。     

Carbon-supported PtAu alloy nanoparticle catalysts for enhanced electrocatalytic oxidation of formic acid

The understanding of the electrocatalytic activity of bimetallic nanoparticle catalysts requires the ability to precisely control the composition and phase properties. In this report, we describe a new strategy in the preparation of a series of carbon supported platinum-gold bimetallic nanoparticles with various bimetallic compositions which were loaded onto a carbon black support and subjected subsequently by thermal treatment (Pt_100−mAu_m/C). The Pt_100−mAu_m/C catalysts are characterized by X-ray diffraction (XRD), transmission electron spectroscopy (TEM), and induced coupled plasma-atomic emission spectroscopy (ICP-AES). The XRD pattern for the bimetallic nanoparticles shows single-phase alloy character. This ability enabled us to establish the correlation between the bimetallic composition and the electrocatalytic activity for formic acid (FA) electrooxidation. The electrocatalytic activities of the catalysts toward FA oxidation reaction are shown to strongly depend on the bimetallic PtAu composition. Within a wide range of bimetallic composition, the Pt₅₀Au₅₀/C catalyst shows the highest electrocatalytic activity for the FA oxidation, with a mass activity eight times higher than that of Pt/C. The high performance of the PtAu/C catalyst can be ascribed to the increased selectivity toward the FA dehydrogenation at the decreased availability of adjacent Pt atoms.     

新β型Ta-TiAl合金的高温开裂行为

利用Gleeble-3800 型热模拟试验机对铸态TiAl-3Ta-x(Cr, W)合金进行了等温热压缩试验,研究了该合金在1150～1300 ℃及 0.1～1 s~(-1)应变速率下的高温变形后的开裂机理。结果表明:铸态合金表面开裂主要以 45°剪切开裂和纵向自由表面开裂为主,但起裂位置不同;合金的热变形损伤以及开裂行为对热加工参数极为敏感,且其开裂程度随着变形温度的降低、应变速率的增大以及变形量的增加而变化。合金在高温高应变速率下热变形,易在晶界附近形成高密度位错、变形位错与滑移带等微缺陷,并在进一步变形中形成微裂纹。微裂纹沿着β晶界、α_2/γ片层内、相邻晶粒之间、晶界与晶内等位置形核。