基于平均飞行航迹的CCO减噪效用研究

近年来，通过优化飞行程序降低机场飞机噪声影响成为机场环境保护的重要研究方向。文章首先建立了基于飞机“噪声-功率-距离”数据的噪声计算模型，介绍了平均飞行航迹以及连续爬升运行(Continuous Climb Opera-tion, CCO)离场程序的相关理论，最后以大型国际机场为实例，使用飞机平均飞行航迹进行噪声预测，运用综合噪声模型计算出噪声影响面积并绘制噪声影响等值线图，比较了CCO离场相对常规的标准仪表离场(Standard Instru-ment Departure, SID)的降噪效果。结果表明，CCO离场程序可有效降低机场噪声影响，在高噪声级影响区域的降噪效果更佳。     

Numerical study of a concept for major repair and replacement of offshore wind turbine blades

Repair and replacement of offshore wind turbine blades are necessary for current and future offshore wind turbines. To date, repair activities are often conducted using huge jack‐up crane vessels and by applying a reverse installation procedure. Because of the high costs associated with installation and removal of offshore wind turbine components and the low profit margin of the offshore wind industry, alternative methods for installation and removal are needed. This paper introduces a novel concept for replacement or installation of offshore wind turbine blades. The concept involves a medium‐sized jack‐up crane vessel and a tower climbing mechanism. This mechanism provides a stable platform for clamping, lowering, and lifting of a blade. A case study of a 5‐MW offshore wind turbine is shown, where common engineering practices were applied and numerical simulations of the marine operations were carried out using finite element and multibody simulation tools. Operational limits for wave and wind actions were established to demonstrate the technical feasibility of the proposed concept.     

45 t门座起重机顶升方案设计

针对国内45 t门座起重机大车行走机构平衡梁裂缝问题。分析平衡梁裂缝产生原因并提出相应的维修方案,并对维修关键技术中的顶升方案设计,采用Ansys软件对其强度进行了有限元分析,同时对维修前后的平衡梁进行分析并对比。将维修方案应用于实际工程,取得了较好效果。该顶升机构修复方案设计符合工程实际,对工程实践具有一定的指导意义。     

An archaeometric study of the Phoenician ceramics found at the São Jorge Castle's hill in Lisbon

A detailed archaeometric study of Phoenician ceramics found in an excavation inside the medieval walls of São Jorge's Castle in Lisbon is described here.Thirty ceramic sherds were studied, grouped into six categories, namely amphorae, containers for domestic use, red slip wares, grey wares, cooking wares and also some indigenous tradition handmade wares.Micro-Raman, X-Ray Fluorescence Emission, X-Ray Diffraction and ground state diffuse reflectance absorption measurements were correlated and used as our main analytical techniques to perform this study. At least three totally different local clay sources were used to produce the here studied pottery, one of alluvial origin using clays collected along the river banks, and another one using clays probably extracted in the oriental part of the Castle's hill. Cooking-ware was made with the use of raw materials with sandy detrital origin. Evidence was also found showing that part of the amphorae, common containers, and grey wares were made with the same raw materials as used in the Phoenician kilns of Almaraz, located in the left margin of the Tagus River, roughly facing Lisbon's Castle hill. The temperatures of the kilns used to fire the amphorae and common containers was in most cases higher than the one used for firing red slip and grey tableware.A detailed laboratorial study of the alluvial clays fired at different temperatures and collected in the Tagus River banks, allowed us, in most cases, to establish the origin of the sources used to produce the Phoenician pottery found in Lisbon.     

提高EBZ-90型掘进机爬坡能力的改进技术

针对EBZ-90型掘进机爬坡能力低,工作效率不高,提出了改进方案,并取得了良好效果。     

低山丘陵区土地整理与可持续利用研究——以广安市广安区为例

本文介绍了土地开发整理的背景与条件,调查测算土地整理、开发潜力,利用MAPG IS软件综合处理研究大量与土地利用相关的基础数据,针对低山丘陵区土地资源利用的现状及特点,从多方面探讨了土地整理的迫切性。依据经济、社会、生态相统一的原则,划定土地开发整理区,确定土地开发整理的方向及重点。最后提出了低山丘陵区土地可持续利用的对策。     

金茂大厦主体结构施工（上）

介绍了金茂大厦主体结构施工的关键——塔楼的模板与脚手体系、泵送混凝土体系、控制垂直度与标高的测量体系。     

筒仓滑模施工技术

结合工程实践,对钢筋混凝土双连体筒仓滑模施工技术进行了概括总结,介绍了滑模的施工工艺和施工过程,解决了滑模施工中经常遇到的一些问题.     

城市传统文化景观空间结构保护

以山地为主的地理和气候条件孕育了我国深厚的山水文化,从原始的聚落到封建城邑都无不反映着对山水格局的精微关注,形成了独特的城市文化景观和生态体系。随着现代城市大规模的快速发展,这一体系正在面临严重的挑战,它们的保护成为中国传统城市、聚落特有的历史任务。     

国家储备粮库浅圆仓滑模设计施工要点

结合工程实例,对模板的安装与调试进行了阐述,对滑模混凝土的配合比进行了介绍,并对滑升的施工方法及施工注意事项进行了论述,以供参考借鉴。