激光打孔技术在光伏背板玻璃上的应用

双玻光伏组件以其抗PID性强、防隐裂、防水汽透过、抗蜗牛纹、可靠性优异、轻量化等诸多优点,在晶硅太阳能组件市占比逐步提高。双玻光伏组件用背板玻璃一般需要预留出线孔,光伏背板玻璃的出线孔主要有两种打孔方式:金钢钻上下同步钻孔的模式和激光打孔。激光打孔以其易维护、可异形孔加工、效率高、生产成本低等优势得到各大玻璃厂的认可。通过分析在实际生产中激光打孔出现的打孔缺陷问题,提出了改善措施,有助于工厂的降本增效。     

基于双时间点检测的毫米波雷达人流量监测方法

针对现有基于视频监控的人流量统计方案成本高、算法复杂且不利于个人隐私保护的局限性，利用毫米波雷达体积小、成本低、分辨率高的特点，提出了一种基于双时间点检测的人流量监测方法。该方法先获取人体目标散射点位置和多普勒频移信息来构成点云数据，然后根据多普勒频移正负来判断人体的运动方向，并筛选具有高多普勒频移值的点云数据以降低干扰点对聚类结果的影响；在双时间点对特定区域内人员数量进行统计，并根据双时间点之间所获取的点云数据聚类结果对所统计人员数据进行修正。实验结果表明，该方法能够用匿名的方式以较高的正确率统计人员进出。     

Research and demonstration on hydrogen compatibility of pipelines: a review of current status and challenges

Hydrogen transportation by pipelines gradually becomes a critical engineering route in the worldwide adaptation of hydrogen as a form of clean energy. However, due to the hydrogen embrittlement effect, the compatibility of linepipe steels and associated welds with hydrogen is a major concern when designing hydrogen-carrying pipelines. When hydrogen enters the steels, their ductility, fracture resistance, and fatigue properties can be adversely altered. This paper reviews the status of several demonstration projects for natural gas-hydrogen blending and pure hydrogen transportation, the pipeline materials used and their operating parameters. This paper also compares the current standards of materials specifications for hydrogen pipeline systems from different parts of the world. The hydrogen compatibility and tolerance of varying grades of linepipe steels and the relevant testing methods for assessing the compatibility are then discussed, and the conservatism or the inadequacies of the test conditions of the current standards are pointed out for future improvement.     

Dual functions of three-dimensional hierarchical architecture on improving the rate capability and cycle performance of LiNi0.8Co0.1Mn0.1O2 cathode material for lithium-ion battery

The main obstacles in lithium-ion battery are limited by rate performance and the rapid capacity fading of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811). Herein, a novel three-dimensional (3D) hierarchical coating material has been fabricated by in situ growing carbon nanotubes (CNTs) on the surfaces of Ni–Al double oxide (Ni–Al-LDO) sheets (named as LDO&CNT) with Ni–Al double hydroxide (Ni–Al-LDH) as both the substrate and catalyst precursor. The resultant LDO&CNT nanocomposites are uniformly coated on the surfaces of NCM811 by the physical mixing method. The rate capability of the resultant cathode material retains to 78.80% at a current rate of 3C. Its capacity retention increases by 6.7–14.42% compared with pristine NCM811 after 100 cycles within a potential range of 2.75–4.3 V at 0.5C. The improved rate capability and cycle performance of NCM811 are assigned to the synergistic effects between Ni–Al-LDO and CNTs. The hierarchical LDO&CNT nanocomposites coating on the surface of NCM811 avoids the aggregation of conductive CNTs and the stacking of Ni–Al-LDO nanosheets. Furthermore, it accelerates Li⁺ and electrons shuttle and reduces the reaction of Li₂O with H₂O and CO₂ in air, which results in Li₂CO₃ and LiOH alkali formation on the NCM811 surface.     

异种铁素体耐热钢接头界面组织及其影响

综述了铁素体与铁素体异种金属焊缝（dissimilar metal welds，DMWs）接头界面组织及其影响。结果表明，在焊后热处理或运行温度下的铁素体钢DMWs接头的不均匀界面组织中，通常会形成脱碳层和增碳层。在铁素体钢DMWs焊接接头界面组织影响因素中，焊缝金属的化学成分有重要影响；焊后热处理规范（温度和时间）、工作温度下运行时间的影响较为突出；焊接工艺参数的影响亦不可忽略。异种钢接头界面处近缝区裂纹的产生，以及接头的蠕变强度随Larson Miller 参数增大而下降等不利影响，均为异种钢界面碳迁移行为所导致。焊缝成分控制法是接头界面组织控制或改善的必要条件，而脱碳层部位转移法能有效防止裂纹发生，亦是接头安全运行的重要工艺措施之一。     

铌对取向硅钢冷轧组织织构的影响

采用光学显微镜(OM)、电子背散射衍射(EBSD)等研究了铌对取向硅钢冷轧过程中的组织与织构的影响。结果表明:含铌正火板和不含铌正火板经冷轧后都是条带状组织,但含铌冷轧板在宽度方向更窄。铌元素的存在对织构也具有优化作用,经过中间退火后,含铌冷轧板二次冷轧织构得到明显改善,相较于不含铌二次冷轧板拥有强度较低的旋转立方织构以及强度较高的{111}<112>织构,其取向密度最高可达12.460。     

爆炸载荷下空孔缺陷与爆生裂纹扩展行为研究

空孔在岩石巷道直眼掏槽爆破中具有重要作用,为研究空孔及其缺陷在爆炸荷载作用下的扩展行为和作用机理,以PMMA代替岩石材料,利用预制裂纹代替空孔缺陷,借助动态焦散线系统和理论分析为手段,研究不同间距下空孔、空孔处预制裂纹、爆生裂纹动态扩展规律及机理,分析不同"径距比"与掏槽效果的关系。研究结果表明:在装药量一定的情况下,随着炮孔与空孔距离的变化,爆生裂纹扩展距离呈现递增而预制裂纹扩展距离呈现递减的趋势,但都存在极值;当炮孔与空孔距离较小时,爆生裂纹和预制裂纹扩展及相互作用最复杂,爆生裂纹扩展经历由压缩应力波为主,表现为直线的前期扩展;由空孔处发射应力波和压缩应力波共同作用下,爆生裂纹偏离炮孔与空孔连心线的中期扩展,以及由空孔应力集中区作用使爆生裂纹向空孔方向偏移的后期阶段;预制裂纹扩展经历由空孔处应力集中作用下,表现为直线的前期扩展,以及由爆生裂纹处反射拉伸波作用使其向爆生裂纹发展的后期阶段;当炮孔与空孔距离较大时,反射应力波及应力集中效应对爆生裂纹和预制裂纹扩展在减弱,爆生裂纹与预制裂纹扩展行为仅有前期直线扩展阶段。"径距比"的大小对爆破效果影响较大,直眼掏槽爆破应以最优"径距比"作为掏槽爆破参数设计的依据。     

贵州职业技术学院数据中心双活技术架构的研究

The importance of data processing and storage to colleges and universities is increasing day by day. However, many colleg- es and universities are still at a low level in the process of data recovery and application reduction, and its RPO and RTO indicators need to be improved by adopting the dual active technology architecture. Taking the Guizhou Vocational Technology Institute as an example, this paper focuses on the analysis of the architecture of the double active data center, aiming at the actual situation of the college, and gradually realizes multiple disaster recovery level of data level, application level and business level.     

Analytical study of surface wave multiple refraction in boundary of a scalar impedance surface with a tensor impedance surface

In this paper, the multiple refraction phenomenon is investigated on the boundary of a scalar impedance surface (SIS) and a tensor impedance surface (TIS). When a surface wave (SW) propagates on the SIS and radiates to the boundary of the TIS, the propagation direction of it is changed and the refraction phenomenon is accrued. The method that is proposed in this paper can predict the multiple refraction for the SW. Moreover, another analytical method is introduced for designing the proposed structure which the double refraction (DR) occurs at arbitrary angles on it. Using it, a sample of the structure is designed by printed circuits in 15.2GHz and the results are verified by the full‐wave simulation and measurement. The results are shown that in the structure, DR is occurred in 2° and 22° as predicted. The proposed method can provide many applications such as design of SW power dividers based on the TISs, impedance surface based waveguides, holographic antennas, and feeding of array antennas.     

An efficient method of generating vortex electromagnetic wave based on double‐layer transmissive metasurface

A broadband double‐layer transmissive metasurface (TMS) for effective generate vortex electromagnetic wave is presented in this paper. The proposed TMS consists of two types of elements. The first element is composed of a multi‐resonant dipole and four metal vias. The metal vias increase the coupling strength between the upper and lower layers to improve transmission efficiency. On the basis of the first element, the second element adds stubs to ensure sufficient phase shift. The far‐field cross polarisation is eliminated by special element arrangement. Then, a centre‐fed linear polarisation TMS is designed to generate orbital angular momentum beams with mode l = ? 1. The proposed TMS is designed, manufactured and measured to verify the proposed design. The measured results indicate that a maximum gain of 20.8 dBi and narrow divergence angle of ±5° are achieved at 18 GHz. Furthermore, mode purity is higher than 86.1% within the 17 to 19 GHz band. The proposed double‐layer TMS saved costs, reduced weight and without assembly error is a good candidate for OAM generator.