Anchoring single Pt atoms on hollow Ag3VO4 spheres for improved activity towards photocatalytic H2 evolution reaction

The high cost of noble metal catalysts has been a great bottleneck for the catalyst industry. Using the noble metal at a single-atom level for catalytic applications could dramatically decrease the cost. The impacts of single Pt atoms on the photocatalytic performance of Ag₃VO₄ have been investigated and reported. In this report, single Pt atoms were anchored on the surface of Ag₃VO₄ (AVO) as a cocatalyst, and the resultant composite photocatalyst has been studied for photocatalytic H₂ production from water driven by visible light. The as-prepared AVO particles are hollow nanospheres in the monoclinic phase with a bandgap of 2.20 eV. The light absorption edge of AVO/Pt is slightly red-shifted compared to that of the pristine AVO, indicating more visible light absorption of AVO/Pt. The XPS peaks of Ag, V, and Pt exhibit a significant shift after AVO and Pt get into contact, suggesting the strong interaction between the surface Ag and V atoms, and single Pt atoms. After 3-h illumination, the photocatalytic H₂ evolution amount from AVO/Pt is improved up to 1400 μmol, which is 2.8 times that on the bare AVO. Such efficient photocatalytic H₂ evolution on AVO/Pt is still maintained after five reaction cycles. The better photocatalytic performance of AVO/Pt has been attributed to the more efficient visible light utilization and the lower interfacial charge transfer resistance, as demonstrated in the DRS and EIS spectra. The presence of the surface Pt atoms also leads to a higher amount of reactive radicals, which could efficiently promote the surface redox reactions.     

Adaptive fuzzy control for nontriangular form systems with time-varying full-state constraints

This article investigates an adaptive fuzzy tracking control problem for a class of nontriangular form systems with asymmetric time-varying full state constraints. Unknown functions are approximated by the fuzzy logic systems. A domination approach is employed to tackle the nontriangular form structure. Time-varying asymmetric barrier Lyapunov functions (ABLFs) are adopted to ensure full-state constraints satisfaction. Based on the backstepping technique and time-varying ABLFs, an adaptive controller is proposed and guarantees that all the signals in the closed-loop system are ultimately bounded and the time-varying full state constraints are met. Simulation examples are presented to further demonstrate the effectiveness of the proposed approach.     

Rectilinear Electromechanical Pumping Developed Successfully in China

Recently, the special subject-development and application of rectilinear electromechanical pumping undertaken by Jianghan Petroleum Machinery Factory and China University of Petroleum （East China） Electromechanical Project Institute, which is the component of national key project for domestic petroleum equipment, new material development and application technology during the period of the 11 th Five-Year Plan,     

自喷井电动清蜡绞车的研制

针对目前石油钻采用清蜡绞车总体结构设计不合理以及实用性不强等技术难题,研制开发了自喷井电动清蜡绞车。该绞车的核心部件包括过载保护安全装置、牙嵌离合器轴套、自动/手动互换装置、计量装置以及密封装置。在清蜡绞车自动工作中,当清蜡刮刀遇到较大阻力时,清蜡绞车将接收到反馈信号,可实现智能停车,自动转换为手动状态,以便操作人员检查和排除故障,从而确保了操作的安全性,延长了设备的使用寿命。1000余台电动清蜡绞车的现场应用表明,该产品可以大大降低原油的开采成本,具有良好的经济效益和社会效益。     

新型交流脉冲MIG焊接法的研究

采用自行研制的具有方框形外特性的交流脉冲MIG焊接电源 ,又设计了双凹形焊接电流波形 ,即过零前后的电流波形均为脉冲大电流 ,有利于交流脉冲MIG焊接电弧的连续稳定。按照这个新型交流脉冲MIG焊接方法 ,不必加任何稳弧措施 ,可实现电弧的稳定燃烧 ,解决了电弧磁偏吹的问题 ,具有较好的焊接工艺性能 ,用于压力容器的全位置焊接和铝焊接均有很好的焊缝成型     

合成氨中置锅炉的修复

本文在分析中置锅炉失效原因的基础上，提出了详细的修复措施，为类似情况的设备修复提供了借鉴。     

Synthesis of Mg-α-sialon from the mixture of silicon, aluminum and magnesia powders in a flowing nitrogen atmosphere

Synthesis of Mg-α-Sialon has been investigated by the mixture of silicon, aluminum and magnesia powders in a flowing nitrogen atmosphere in the range of 1300–1600 °C, when Mg-α-Sialon is designed with a chemical formulation of Mg _x Si_12−3x Al_3x O _x N_16−x in present work. The results showed that Mg-α-sialon initially occurred at 1400 °C and basically increased with elevated temperatures. For the samples of x = 0.6, 0.8 and 1.0 the products mainly consisted of Mg-α-Sialon with small amounts of Si, AlN and 21R AlN-polytypoid phases at 1600° C. However, in final products of x = 1.2, 1.4 and 1.6 only a little of Mg-α-Sialon formed and a great amount of Si remained in these samples at all the fired temperatures. Fortunately, the content of Mg-α-Sialon in these samples were obviously increased by adding a small amount of α-Si₃N₄ as seeds before nitridation.     

ABSTRACT

某水库混凝土坝在初期运用中,坝体渗漏量远远超过设计允许值,经专家咨询分析,渗漏的主要原因是由于施工时质量控制不严在混凝土坝体内形成了渗漏通道,故决定在混凝土坝内进行补强灌浆处理,以形成一道阻水帷幕,封堵渗漏通道.实施中,主要利用排水孔进行灌浆和自溢流堰顶钻孔进行补强灌浆,施工单位克服了重重困难,保证施工质量,处理效果良好,渗漏量满足设计要求,3年来大坝运行正常.     

无线局域网技术及应用

无线局域网技术是目前发展迅速的技术，相对于有线局域网有许多优点。随着无线网络产品性能的提高和价格的不断下降，无线局域网技术有着广泛的应用前景。据此对无线局域网的基本概念、特点及其技术作了简单的介绍，提出了无线局域网面向应用的几种解决方案，并对发展前景作了预测。     

唐钢ER70S-6焊丝钢的生产工艺研究及质量分析

介绍了唐钢ER70S-6焊丝钢的特点，对盘条质量进行了分析。对该钢化学成分、冶炼和轧制工艺进行了优化研究，使其综合性能明显改善。