Seasonal and diurnal variations of carbonyl compounds in the urban atmosphere of Guangzhou, China

Seasonal and diurnal variations of carbonyl compounds were investigated at two sampling sites (Liwan and Wushan) in the ambient air of Guangzhou, China. Air samples were collected during 2005 from January to November, and carbonyl compounds were analyzed with HPLC. The results show that carbonyls exhibit distinct seasonal variation. The total concentrations of 21 carbonyls detected ranged from 2.64 to 103.6 μg m⁻³ at Liwan and from 5.46 to 89.9 μg m⁻³ at Wushan, respectively. The average total concentrations of carbonyls at both Liwan and Wushan decreased in order of summer>spring>autumn>winter. Formaldehyde, acetaldehyde, and acetone were the most abundant carbonyl compounds, which accounted for more than 60% of the total concentrations of carbonyls. The mean concentration ratios of summer/winter were all > 1.0 for the total concentrations and the individual carbonyl compound. The diurnal variation of carbonyls was not distinct in this study. The average concentration ratios of formaldehyde/acetaldehyde (C₁/C₂) varied from 0.71 to 1.32 and 0.65 to 1.14 at Liwan and Wushan, respectively, and the average concentration ratios of acetaldehyde/propionaldehyde (C₂/C₃) varied from 5.42 to 7.70 and 5.02 to 13.9 in Liwan and Wushan, respectively. Regarding photochemical reactivity of carbonyls and the ozone production, acetaldehyde, butyraldehyde, formaldehyde, and valeraldehyde account for 75-90% to the total propene-equivalent concentrations, while formaldehyde, acetaldehyde, valeraldehyde, butyraldehyde, and propionaldehyde contribute 89-96% to the total ozone formation potentials (ranging from 105 to 274 μg m^-3). The ozone formation potentials in summer were higher by 1-2 times than those in the other seasons.     

Pollution situation and possible markers of different sources in the Ordos Region, Inner Mongolia, China

In order to investigate the pollution situation for a fast-developing industrial area at its first stage, a systematic study on the gaseous and particulate pollution in the Ordos Region of Inner Mongolia was performed during 9-24 September 2005. The gases SO₂, NO_x, O₃, CO, and the particulates PM₁₀ and PM_2.5 were sampled at five sites in Ordos. Species measured in aerosol were 21 elements, 10 ions, organic carbon (OC), elemental carbon (EC), and the acid-buffering capacity of particulates. Possible markers of sources for different transport directions were firstly investigated, which was a new attempt for clarification of regional transport with different directions. None of the gases exceeded the national standards of China. PM_2.5 contributed most to PM₁₀ at the background site, indicating the greatest contribution of regional transport. Organic matter, crustal material, and sulfate ion were the three dominant species of aerosol, followed by EC, NO₃⁻, NH₄⁺, trace elements, and other ions. The acidity of PM_2.5 was higher than that of PM₁₀, and the buffering capacity in PM₁₀ was higher than that in PM_2.5. Four peaks of pollution aerosol were observed during the 3-week study sampling period, separated by periods of cleaner air. Back-trajectories revealed that the peaks came from the south and the cleaner air from the north. It is the first time to find different markers for aerosols from different transport directions in Ordos. S and Pb, as well as SO₄²⁻, NO₃⁻, and NH₄⁺ appeared to be good markers of southern aerosol in the Ordos, since all showed four clear peaks on days dominated by southern direction. Extremely high peaks of Al and Ti on the 16th and 17th, especially at the dust-monitoring site, indicated good markers for soil dust. Ca and Mg showed earlier peaks on the 16th at the western site, indicating possible markers for western aerosol.     

A Method of Helmholtz Sources in Thermoelasticity

ABSTRACT

The work includes a proposal of solving coupled quasi-static problems of linear thermoelasticity with coupled initial state by Helmholtz potentials. The proposal is based on an extension of the body region to the whole space where the space integral as a particular solution of the Helmholtz initial-boundary value problem is derived. Thermomechanical fictitious sources are separated from the space integral. Their capacities are determined on an approximate way from the boundary conditions in a bounded time interval. The approximated solution of the initial-boundary value problem of thermoelasticity was obtained by contraction of the space integral in space and time.     

Design and analysis of gorlov helical hydro turbine on index of revolution

Energy production in India during 2017–2018 has increased by 5.71%, while 7.39% in 2019, as per the Energy Statistics of India. Due to the ever-increasing demand, Renewable Energy Sources (RES) are used to meet the power demand with low cost and emission. In India, the power generation capacity of micro-hydropower is limited to 1.8% (19749 MW) of the total potential reserve. The conventional turbines may not effectively harness energy for the micro-hydropower system. Traditional turbines are ideally suited for applications requiring a low discharge with a high head or a high discharge with a low head. However, they are futile in ultra-low head implementations. In order to enhance the electricity production from perennial/tidal sources, the Gorlov Helical Turbine (GHT) is suggested. This paper presented a design and analysis of garlov helical hydro turbine on index of revolution. GHT with a diameter and height of 0.600 m is designed for a micro-hydropower system. Nine 3D-GHT's with a diameter and height of 0.600 m is modelled based on varying indices of revolution. The effect of the index of revolution on the performance of the GHT is examined through simulation, MATLAB and field-testing. By analysing the outcomes, it is observed that 0.25 remains the optimum value for the index of revolution of the helix. The output power obtained by MATLAB, SolidWorks simulation and field-testing is 1.175W, 0.951W and 0.657W, respectively.     

迈向21世纪的化学电源

回顾了上世纪化学电源的发展史、所取得的主要成就 ,以及存在的问题。指出化学电源的发展随着电器的发展 ,战争和航空航天事业的需求 ,汽车工业的尾气污染 ,以及环保对电池的限制等发展起来的。对电池本身来说 ,性能是随着电极过程动力学等理论深入以及新材料的出现而不断发展的。着重分析了新世纪化学电源发展前景以及要解决的主要问题 ,可能诞生的新体系取决什么条件 ,以及面临的资源的枯竭和环保的要求。     

积极推进分布式能源系统

阐述积极推进分布式能源系统的基本原因,我国分布式能源系统并网近况,发展天然气分布式CCHP冷热电三联供的意义与几个示范项目和继续完善分布式能源系统的相关政策.     

基于激光传感器的单摆周期测量仪的设计与实现

介绍了在89C51单片机控制下激光传感器的单摆周期测量仪的设计与实现。以市场现有单摆作为研究对象讨论了单摆周期测量的误差来源。通过使用激光传感器计数单摆摆球经过平衡位置的次数与89C51单片机定时器精确的计时，避免了人为计数与计时所引起的操作误差。本单摆测量仪精确度高、成本低廉、稳定性好、操作简单，具有一定的推广应用价值。     

燃煤灰渣活性差异及来源研究

粉煤灰、沸腾炉渣和固硫灰渣是三种具有代表性的燃煤灰渣,因生成方式与生成温度不同,火山灰活性存在较大差异。本文采用改进的28 d抗压强度比方法研究其活性差异,并在矿物组成及颗粒形貌等方面探讨活性差异来源。研究结果显示:沸腾炉渣和固硫灰渣活性相近,明显高于粉煤灰;不同种类燃煤灰渣的活性差异主要来源于其矿物组成及颗粒形貌差异。     

抗运动疲劳食源性活性成分的研究进展

运动疲劳是一种当训练和比赛负荷超过机体所承受的能力时,产生的短暂的生理机能减退的现象。一般包括肌肉疲劳、内脏疲劳和神经疲劳。对于运动员来说,消除疲劳的方法有整理活动、物理疗法、睡眠、温水浴、营养和药物等。近年来,食源性活性成分多种多样,包括活性肽类、氨基酸类、糖类、维生素、生物碱和皂苷类等天然活性产物,在不同的领域都具有重要的作用,尤其是在抗运动疲劳中逐渐呈现出经济实惠、治疗多样化且便捷高效的独特优势,日益受到大众的关注。本文分别以运动疲劳机制和食源性活性成分为基础,着重对具有抗运动疲劳作用的食源性活性成分进行研究概述,为在食品领域解决运动疲劳性开拓思路,为研究具有抗运动疲劳作用的新型的食品提供理论依据,进而促进多功能性食品的发展。     

一种基于物联网的高危辐射源综合监管平台的设计

系统利用传感器的特性对辐射源上电子标签的信息自动采集,并对各辐射源储存库与应用现场进行实时监控,及时发现辐射源使用等活动中的异常状态,自动分级发出报警信息,实现辐射源监管的目的;本平台面向环保行业,在Web Services技术支持下,以面向服务架构为指导,探索以物联网中间件为基础的物联网组网模式、结构与组织体系,是对新型物联网应用模式的探索和现有物联网应用模式的补充。