一种基于实时几何测距的船桥主动防撞方法

本文提出一种基于实时几何测距的船桥主动防撞方法。该方法对船的改动量甚微,仅需维持多项距离矩阵,通过告警逻辑矩阵进行展示与告警,能起到很好的船桥防撞提示效果。     

高湿黏性颗粒在聚四氟乙烯微孔膜滤料表面沉积特性的数值模拟

基于聚四氟乙烯(PTFE)微孔膜滤料扫描电镜(SEM)图像，建立PTFE微孔膜滤料微观结构模型，采用计算流体力学和离散单元法(CFD?DEM)耦合的方法对黏性颗粒在微孔膜滤料表面沉积特性进行模拟，引入液桥力模型，忽略范德华力的作用，统计计算域内颗粒的受力情况，分析了不同表面能条件下3~6 ?m粒径颗粒在微孔膜滤料表面的沉积特性，将模拟结果与黏附效率的经验公式进行对比。结果表明，黏附效率与经验值、颗粒受力与液桥力模型的相对误差均在6%以内，CFD?DEM耦合计算方法可用于模拟不同环境湿度条件下的颗粒沉积；过滤风速、粒径与黏性是影响沉积形态的重要因素，提高过滤风速及增大颗粒粒径与黏性，颗粒更易在滤料表面形成稳定的树突结构，黏附效率及含尘压降增加。环境相对湿度影响两物体间液桥体积，接触力影响颗粒沉积，当增加表面能与液桥体积时，接触力及液桥力均相应增加，根据受力平衡原理，环境相对湿度对颗粒沉积影响很大。     

Fabrication of novel ZnTe-based photocatalyst: Synergistic effect of dye sensitization and bridge engineering for boosting hydrogen evolution over ZnTe

Herein, a novel ZnTe-based photocatalyst is successfully synthesized via a facile combination of water-bath and hydrothermal processes. Morphology characterization and X-ray diffraction analysis reveal that ZnTe presents irregular granular shape and cubic crystal structure. Moreover, Mott-Schottky measurement shows that the conduction band potential of ZnTe is ?0.84 V (vs NHE). With Eosin Y (EY) sensitization, ZnTe exhibits superior photocatalytic hydrogen evolution activity (223.5 μmol g^?1 h^?1). Meanwhile, WC-ZnTe heterojunction is constructed by depositing ZnTe nanoparticles on bulk WC and obtains the optimal H₂ generation rate (559.1 μmol g^?1 h^?1) under EY sensitization. Electrochemical and photoluminescence results further prove that WC as electron bridge could reduce the interfacial resistance and suppress e^?-h⁺ pairs recombination. This study explores the potential application of ZnTe as a newly active photocatalyst in photocatalytic water splitting, and emphasizes the synergistic effect of dye sensitization and bridge engineering.     

Bidirectional energy storage photovoltaic grid-connected inverter application system

A novel topology of the bidirectional energy storage photovoltaic grid-connected inverter was proposed to reduce the negative impact of the photovoltaic grid-connected system on the grid caused by environmental instability. Using the proposed Inverter as a UPS power supply in case of a grid failure, storage electrical energy and regulating the energy delivered to the grid for reducing the pressure on the grid. A new artificial fish-swarm algorithm and variable step voltage perturbation method were presented to track the maximum power point of the solar panels. Analysis was done to reduce the output ripple of the inverter and sinusoidal pulse width modulation (SPWM) was selected to control the inverter. Model simulation was performed using PSpice software to obtain the volt-ampere characteristic curve of the solar panel output. The solar array simulator was used to verify the effect of maximum power point tracking at different light intensities. The study concludes that the maximum power point tracking (MPPT) efficiency of the bidirectional energy storage photovoltaic grid-connected inverter designed was as high as 99.9%. The distortion rate of the grid-connected current waveform was within 2% and the DC current component was less than 0.5%. The output voltage and power were in full compliance with the grid connection standard.     

桥梁新旧盖梁自密实补偿收缩混凝土拼接施工技术

结合兴宁至汕尾高速公路海丰至红海湾开发区段一期工程实际,对新旧盖梁拼接施工技术进行总结。通过施工技术的创新有效解决传统拓宽拼接桥梁中新旧结构的连接问题。该技术方案具有较好的经济和社会效益,可推广至类似工程中应用。     

A full moon in another land: The Moon Bridge in the Japanese garden of the Huntington Library

In 1913, a so-called Moon Bridge was built in the Japanese garden of the Huntington Library in San Marino, California, USA as a fruit of the Japonism in the Western world at that time. The master carpenter was Toichiro Kawai, a Japanese immigrant from Yokohama who was originally a ship carpenter.The bridge is made of wood and shaped in the exaggerated arch form, which classifies the bridge as a “drum bridge” (Taiko-bashi) in Japanese culture. However, the unique structural form of this bridge, the “woven arch,” is rare in building history.This paper aims to explore why and how such a bridge appeared in such a place and time. For this purpose, we go from the historical background to its construction history, from the concept of the designer to the detailed design methods. Data come partly from the author's first-hand investigation and the limited local archive. The most interesting discoveries were made during the detailed on-site investigation, including the fact that the bridge is designed to express the metaphor of “perfection” (full moon) through its geometrical features, and the design is based according to traditional Japanese methods.     

循环荷载作用下钢桥面铺装疲劳损伤失效行为研究

针对钢桥面铺装工程中普遍采用的改性沥青(Stone Matrix Asphalt,SMA)、浇筑式沥青(Guss asphalt,GA)、环氧沥青(Epoxy asphalt,EP)混合料双层铺装结构,进行了循环车载作用下钢桥面与沥青混凝土铺装疲劳损伤特性理论分析与试验研究。基于疲劳损伤度,研究了钢桥面铺装疲劳损伤失效行为和疲劳开裂过程中损伤场、应力和应变场动态演变机制,推导出疲劳失效时的损伤场、应力和应变场计算表达式,并给出钢桥面铺装疲劳寿命理论公式。以三座钢箱梁桥桥面铺装(润扬长江大桥2005,南京长江三桥2005,苏通大桥2008)为例,对不同铺装结构组合方案下的复合梁进行疲劳试验分析和使用寿命理论预测。实例研究结果表明,钢桥面铺装疲劳损伤失效行为预估模型合理可行;相较于改性沥青、浇筑式沥青,环氧沥青混合料具有较强高的强度低变形能力,更适合于大跨径钢桥面铺装抗疲劳的设计要求;由环氧沥青混合料组合而成的“双层环氧沥青混凝土”和“浇注式沥青混凝土(下层)+环氧沥青混凝土(上层)”的抗疲劳性能优于其它沥青混合料铺装结构组合方案,同等厚度组合情况下疲劳使用寿命可延长1倍~2倍以上;“双层环氧沥青混凝土”已应用于润扬长江大桥、南京长江三桥和苏通长江大桥钢桥面工程,并已成功运行10年以上,其跟踪观测结果良好。     

浅谈桥梁深基坑挡土墙防护施工方案

本文根据该项工程实际情况和相关技术标准、水文地质特征,对施工准备、测量放线、基坑开挖、挡土墙施工、基坑监测等关键部分进行深入研究。