牙哈凝析气田大气环境影响回顾评价

为更好地了解牙哈凝析气田开发建设对大气环境质量的影响,根据牙哈凝析气田6年的大气环境监测资料,采用spearman秩相关系数法对牙哈凝析气田开发10年来的环境空气质量进行回顾评价及变化趋势分析.结果表明:牙哈凝析气田大气中主要污染物SO2、NMHC(非甲烷总烃)均总体呈下降趋势,NO2呈上升趋势,而在2008年急剧下降,整体大气环境质量呈现好转趋势.牙哈凝析气田开发区块环境空气质量有了明显的改善,各项大气环境治理措施取得了显著的环境效益.     

我所知道的槇文彦

自二战结束后半个多世纪以来,日本由于战后重建的需要和经济快速发展而提供的可能,产生了大规模的建设过程,也涌现了大批有高度成就的建筑师。在文化方面,日本既保持了原来本土的遗产,又在隋唐以来受中国文化的滋养和明治维新以后受西方列强的影响。特别是二战以后,西方的影响更是在加速扩展。这在建筑方面就表现得尤为清楚。在这50多年来,战前盛极一时的复古风、帝冠式逐渐式微。但民族主义     

“积极保护”理念与济南老城保护规划

进入21世纪,济南市城市化进程不断加快,保护与发展的矛盾日益突出。如何处理老城保护与经济发展的关系,如何在保护特色风貌的同时实现老城的现代化,成为急需解决的问题。济南市通过对老城保护存在问题的分析,阐述了基于规划管理角度的"积极保护"理念内容,即注重保护的科学、统筹、整体、重点、有机、特色六个方面,并编制了《济南商埠风貌区规划》等规划,在实践层面进行了探索,提出了相应的实施建议。     

Prediction of the crack condition of highway pavements using machine learning models

Departments of Transportation regularly evaluate the condition of pavements through visual inspections, nondestructive evaluations, image recognition models and learning algorithms. The above methodologies, though efficient, have drawn attention due to their subjective errors, uncertainties, noise effects and overfitting. To improve on the outcomes of the shallow learning models already used in pavement crack prediction, this paper reports on an investigation of the use of recursive partitioning and artificial neural networks (ANN; deep learning frameworks) in predicting the crack rating of pavements. Explanatory variables such as the average daily traffic and truck factor, roadway functional class, asphalt thickness, and pavement condition time series data are employed in the model formulation. Overall, it is observed that the recursive partitioning (regression tree – R² > 0.8 and classification tree – R² > 0.6) and ANN (continuous response – R² > 0.8 and categorical response – R² > 0.6) are compelling machine learning models for the prediction of the crack ratings based on their goodness-of-fit statistics, mean absolute deviation (MAD < 0.4) and the root mean square errors (RMSE between 0.30 and 0.65).     

微机械差动电容压力传感器的研究

文中介绍以Ｎ型单昌硅为基底,利用微机械加工研制而成的一种中央上举开放式差动电容压力传感器的结构及其设计。     

进口工业设备液压润滑系统管道的安装

重点介绍了进口大型冶金、加工设备的液压润滑系统管路安装时,如何与国内技术标准,施工方法打结合以达到设备所要求的精度以及施工时应注意的问题。     

浅谈建筑给排水设计中的常见问题与解决措施

随着人民生活水平的不断提高,我国建筑业的迅速发展,为满足居民对高品质住宅的需求,要求建筑设计和施工具有更多的适应性、灵活性,要求赋予住宅更高的科技含量和文化内涵.建筑给排水设计技术也日趋完善,给排水设计是建筑设计的一个很重要的方面,,同时与人们的日常生活也是密切相关,因此其设计过程中应本着实用、安全、经济的原则.现对其的发展现状进行了介绍及常见问题时行了分析探讨,并提出一些解决办法.     

Distribution of respiratory droplets in enclosed environments under different air distribution methods

The dispersion characteristics of respiratory droplets are important in controlling transmission of airborne diseases indoors. This study investigates the spatial concentration distribution and temporal evolution of exhaled and sneezed/coughed droplets within the range of 1.0 − 10.0μm in an office room with three air distribution methods, specifically mixing ventilation (MV), displacement ventilation (DV), and under-floor air distribution (UFAD). The diffusion, gravitational settling and deposition mechanism of particulate matter were accounted by using an Eulerian modeling approach with one-way coupling. The simulation results indicate that exhaled droplets up to 10μm in diameter from normal human respiration are uniformly distributed in MV. However, they become trapped in the breathing zone by thermal stratifications in DV and UFAD, resulting in a higher droplet concentration and an increased exposure risk to other room occupants. Sneezed/coughed droplets are more slowly diluted in DV/UFAD than in MV. Low air speed in the breathing zone in DV/UFAD can lead to prolonged human exposure to droplets in the breathing zone.     

高边坡压力分散型预应力锚索施工工艺研究

压力分散型预应力锚索由于具有较多优点而在复杂高边坡加固工程中应用越来越广泛，施工中结合边坡岩体性质和设备条件科学合理的选择施工工艺是其取得理想效果的关键环节。本文结合金丽温高速公路17标段工程实例，从施工组织、现场试验、钻孔、注浆、张拉、监测等方面对压力分散型预应力锚索施工工艺作了详细论述，为类似工程提供一些借鉴经验。     

Numerical evaluation of wind effects on a tall steel building by CFD

A comprehensive numerical study of wind effects on the Commonwealth Advisory Aeronautical Council (CAARC) standard tall building is presented in this paper. The techniques of Computational Fluid Dynamics (CFD), such as Large Eddy Simulation (LES), Reynolds Averaged Navier-Stokes Equations (RANS) Model etc., were adopted in this study to predict wind loads on and wind flows around the building. The main objective of this study is to explore an effective and reliable approach for evaluation of wind effects on tall buildings by CFD techniques. The computed results were compared with extensive experimental data which were obtained at seven wind tunnels. The reasons to cause the discrepancies of the numerical predictions and experimental results were identified and discussed. It was found through the comparison that the LES with a dynamic subgrid-scale (SGS) model can give satisfactory predictions for mean and dynamic wind loads on the tall building, while the RANS model with modifications can yield encouraging results in most cases and has the advantage of providing rapid solutions. Furthermore, it was observed that typical features of the flow fields around such a surface-mounted bluff body standing in atmospheric boundary layers can be captured numerically. It was found that the velocity profile of the approaching wind flow mainly influences the mean pressure coefficients on the building and the incident turbulence intensity profile has a significant effect on the fluctuating wind forces. Therefore, it is necessary to correctly simulate both the incident wind velocity profile and turbulence intensity profile in CFD computations to accurately predict wind effects on tall buildings. The recommended CFD techniques and associated numerical treatments provide an effective way for designers to assess wind effects on a tall building and the need for a detailed wind tunnel test.