Preparation of a novel Cd2Ta2O7 photocatalyst and its photocatalytic activity in water splitting

Cd₂Ta₂O₇, which showed high photocatalytic activity for overall water splitting, was synthesized by sol–gel method. Its maximum activity increased from 46.2 μmol-H₂/h and 23.0 μmol-O₂/h into 173.0 μmol-H₂/h and 86.3 μmol-O₂/h when 0.2 wt.% NiO was loaded as co-catalyst. The band structure of Cd₂Ta₂O₇ was calculated by a plane-wave-based density functional theory (DFT). The valence band is mainly formed by O 2p AO's, and the conduction band predominantly consists of Ta 5d, O 2p and Cd 5s5p AO's. Cd atoms endue new features different from other tantalates, and its effect on the band structure of Cd₂Ta₂O₇ was discussed.     

Further remark on P systems with active membranes and two polarizations

P systems (or membrane systems) are a class of distributed parallel computing devices of a biochemical type. In this paper, some restrictions on the general form of the developing rules are considered, under which it is still possible to solve NP-complete problems. We present an algorithm for deterministically deciding SAT in linear time by P systems with active membranes using two polarizations and rules of restricted versions of types (a), (c), (e). The result obtained in this paper answered an open problem proposed by Alhazov and Freund in the aspect of computing efficiency.     

燃煤热水锅炉监控系统

本文介绍了基于IPC-PLC燃煤供暖热水锅炉监控系统的硬件配置及其功能的软件实现。分析了燃烧控制系统、压力控制系统及流量控制系统的特点,采用了相应的控制算法。实践证明,该系统达到了锅炉燃烧工况良好、节能降耗的工艺要求,且运行稳定可靠。     

三类甘薯活性物质及其生理效应

参考近10年来的研究成果，论述了甘薯糖蛋白、甘薯多糖、甘薯多酚的化学组成及其生物。学功效，并对有关研究热点进行了展望．     

基于背景自适应生成的监控图像运动目标分割

通过插值填充运动目标区域,生成首帧参考背景.背景更新时,结合当前帧和前一帧图像及其参考背景,根据亮度补偿动态生成当前帧参考背景.然后采用减背景方法对目标进行粗提取,再经目标阴影去除和形态学处理后分割出精确的运动目标.实验结果表明,该方法是有效可行的,能达到实时处理的要求,同时对场景光照变化具有较好的自适应性.     

冷却维修法在临濮线外管道大修中的开发与运用

高性能的管道防腐蚀层在确保管道有效运行体系中发挥着重要作用。本文介绍了冷却维修法的原理、方法及试验效果,阐述了冷却维修法在夏季管道大修中的技术优势。试验证明冷却维修法完全达到了埋地管道防腐蚀层的性能要求。同时,对失效管线防腐蚀层的更新是经济、安全的。     

Effects of temperature and strain rate on microstructure and mechanical properties of high chromium cast iron/low carbon steel bimetal prepared by hot diffusion-compression bonding

The objective of this study is to develop a hot diffusion-compression bonding process for cladding low carbon steel (LCS) to high chromium cast iron (HCCI) in solid-state. The influence of temperature (950–1150 °C) and strain rate (0.001–1 s⁻¹) on microstructure, hardness and bond strength of the HCCI/LCS bimetal were investigated. The interface microstructure reveals that the unbonded region can only be found for 950 °C due to lack of diffusion, while the intergrowth between the constituent metals occurred at and above 1100 °C. When bonding temperature increases to 1150 °C, a carbide-free zone was observed near the interface on the HCCI layer, and the thickness of the zone decreases with an increase of bonding strain rate. These evolutions indicate that the bond quality was improved by raising temperature and reducing strain rate due to the increase of element diffusion. The hot compression process of the bonding treatment not only changes the carbide orientation of the HCCI, but also increases the volume fraction of Cr–carbide. Based on the microstructural examinations and mechanical tests, the optimum bonding temperature and bonding strain rate are determined to be 1150 °C and 0.001 s⁻¹, respectively.     

Rapid chemical synthesis and optical properties of ZnO ellipsoidal nanostructures

ZnO ellipsoidal nanostructures were rapidly synthesized using a chemical synthesis method at 90 °C without the assistance of aging procedure, calcination, sonication, microwave, laser or any organic additives. The effects of pH values and Zn²⁺ concentration on the morphologies of ZnO nanostructures were investigated. The instantaneous underdeveloped ZnO nanostructures were successfully obtained by using the electrophoretic deposition (EPD). Based on the experimental results, growth mechanism of ellipsoidal ZnO nanostructures was proposed. The ellipsoidal nanostructures are self-assembled by the oriented-attachment growth of primary nanoparticles, involving the end-to-end oriented-attachment along the major axis and the side-by-side oriented-attachment along the minor axis. Two half-ellipsoids of the ZnO nanostructures germinate in sequence. The UV–vis absorption and photoluminescence of the ellipsoidal nanostructures was also studied. This work presents a simple and ultra-fast route for large-scale fabrication of ZnO ellipsoidal nanostructures.     

Gd2O3 doped 0.82Bi0.5Na0.5TiO3–0.18Bi0.5K0.5TiO3 lead-free piezoelectric ceramics

Gd₂O₃ (0–0.8 wt.%)-doped 0.82Bi_0.5Na_0.5TiO₃–0.18Bi_0.5K_0.5TiO₃ (BNKT18) lead-free piezoelectric ceramics were synthesized by a conventional solid-state process. The effects of Gd₂O₃ on the microstructure, the dielectric, ferroelectric and piezoelectric properties were investigated. X-ray diffraction (XRD) data shows that Gd₂O₃ in an amount of 0.2–0.8 wt.% can diffuse into the lattice of BNKT18 ceramics and form a pure perovskite phase. Scanning electron microscope (SEM) images indicate that the grain size of BNKT18 ceramics decreases with the increase of Gd₂O₃ content; in addition, all the modified ceramics have a clear grain boundary and a uniformly distributed grain size. At room temperature, the ferroelectric and piezoelectric properties of the BNKT18 ceramics have been improved with the addition of Gd₂O₃, and the BNKT18 ceramics doped with 0.4 wt.% Gd₂O₃ have the highest piezoelectric constant (d₃₃ = 137 pC/N), highest relative dielectric constant (ε_r = 1023) and lower dissipation factor (tan δ = 0.044) at a frequency of 10 kHz. The BNKT18 ceramics doped with 0.2 wt.% Gd₂O₃ have the highest planar coupling factor (k_p = 0.2463).