公共场所人群加速度异常检测系统

针对目前基于速度检测公共场所密集人群异常行为存在的检测准确率低、使用范围局限的问题,从人群的加速度角度对可能导致公共安全事故的人群异常行为进行研究,提出了一种基于加速度检测人群异常行为的算法,并基于该算法实现了针对人群逃散、人群聚集、人群拥挤和人群逆行4种异常行为检测的系统。首先,利用金字塔Lucas-Kanade光流法进行特征点跟踪;然后,在获取到特征点的速度矩阵基础上进一步计算其加速度矩阵,反映速度的整体变化;最后,从加速度大小和方向两方面检测人群异常行为。结果表明,所提算法检测用时较少,相比基于速度检测的对比算法,检测的正确率提高到80%,误报率降低为5%。     

不同填料对潜流湿地PO43——P去除效果的影响

为解决中国西部农村生活污水的面源污染问题,采用吸附动力学和热力学试验,测定了6种天然和非天然潜流湿地填料吸附水中PO₄3--P的特性。结果表明:填料的吸附平衡时间均为24 h;对PO₄3--P的动力学吸附过程符合Elovich模型;温度为15~35℃时,砾石、混凝土、红砖、瓷砖和生物炭对PO₄3--P的平衡浓度为40 mg/L;砾石和生物炭对PO₄3--P的吸附过程符合Langmuir模型;混凝土、瓷砖、红砖和无烟煤对PO₄3--P的吸附过程符合Freundlich模型;吸附过程主要以物理吸附为主且吸热,PO₄3--P在填料中的吸附为焓推动作用,均不属于自发过程;在24 h时,混凝土对PO₄3--P的去除率为73.45%;因此,混凝土对PO₄3--P吸附效果最佳,更适宜作湿地填料。     

北黄海北部表层沉积物中多环芳烃的分布特征及控制因素分析

为研究北黄海北部沉积物中多环芳烃（PAHs）的分布特征及控制因素,于2016年7月在北黄海北部采集31个表层沉积物,并对沉积物中16种PAHs、总有机碳（TOC）和粒度进行分析测定。研究结果表明:该海区沉积物中多环芳烃的总含量范围在3.54~93.07 ng/g之间,平均含量34.50 ng/g,在辽东半岛东岸多环芳烃的分布呈由近岸向外海逐渐递减的趋势,总体看该区域PAHs的污染处于较低水平。主成分分析表明该海区沉积物中多环芳烃的主要来源是化石燃料燃烧源和石油源。该区域有机碳的分布受鸭绿江物质输入的影响,自东向西含量逐渐递减。粒度则呈现长山列岛以东,颗粒较粗;长山列岛以西,颗粒较细,空间变化相对较小。进一步分析表明,PAHs的分布主要受鸭绿江、辽东沿岸中小河流以及黄河的物质来源的影响;此外,该区水动力条件也是影响多环芳烃分布的重要因素。     

烟气源热泵波纹板蒸发器冷凝换热特性数值研究

对波纹板蒸发器中的烟气冷凝换热进行数值模拟,运用Fluent软件得出烟气温度场、速度场、冷凝水浓度场;分析烟气特性和波纹板蒸发器的结构参数对冷凝换热的影响,发现当过量空气系数较小、烟气流速为2~3 m/s、烟道宽度为10~12 mm、波纹高度为18~20 mm、波纹节距为36~40 mm时,能带来较好的换热效果。通过与平板换热器进行对比,波纹板的冷凝换热效果优于平板,为工程设计提供理论基础和参考。     

广东省农村民居地震安全示范工程实施现状分析

结合广东各地农村经济发展状况和民居特点,简要阐述了全省地震安全农居示范工程实施基础,较系统地介绍了当前示范工程实施情况,对存在的不足和工作难点进行了比较深入的分析和科学总结,并提出行之有效的解决方案。     

Effects of Metsulfuron-Methyl on the Microbial Population and Enzyme Activities in Wheat Rhizosphere Soil

The effects of metsulfuron-methyl, a sulfonylurea herbicide, on the wheat soil microorganisms were evaluated by the methods of microbial inoculation culture, and the activities of three enzymes were measured using the colorimetric method. The tolerant microorganisms that can resist 500 μ g·g^?1 metsulfuron-methyl in the counting culture medium were studied specially. Metsulfuron-methyl distinctly inhibited the common aerobic heterotriphic bacteria, but the effects on common fungi and common actinomycete were not evident. In the meantime, the number of tolerant fungi increased greatly in the rhizosphere after the application of metsulfuron-methyl in contrast to the significant decrease of the amount of tolerant actinomycete. It indicates that fungi might turn into the dominant microbial type and actinomycete is the sensitive factor in the soil polluted by sulfonylurea residues. The population of aromatic compounds–decomposing bacteria, aerobic azotobacter, and nitrite bacteria all increased in the earlier period, but the aerobic azotobacter decreased rapidly in number 30 days later, and the amount of nitrite bacteria also showed a temporary decrease with time 15 days later. However, the denitrifying bacteria just began to increase significantly after the crops had grown for 50 days. The amount of sulfur-oxidizing bacteria gradually decreased with the growth of crops, and so were the sulfate-reducing bacteria after metsulfuron-methyl application. To all types of microorganisms, there were more microbes in rhizosphere samples than those in nonrhizosphere except aerobic azotobacter. It means the growth of wheat root system can stimulate the growth of most microorganisms. The activities of hydrogen peroxidase and polyphenol oxidase in soil samples after metsulfuron-methyl application were notably lower than those in the control, and the difference of the activities between the samples of rhizosphere and nonrhizosphere was evident. On the contrary, the activity of dehydrogenase was not inhibited by the application of metsulfuron-methyl, and the rhizosphere effect was not obvious either.     

Governmental policies drive the LUCC trajectories in the Jianghan Plain

The prosperity of farmers is closely tied to governmental policies. The Jianghan Plain is an important region for commodity grains, cotton and edible oil for China. The trajectories of land use and land cover change (LUCC) of the study area from 1995 to 2010 were studied based on the LUCC database of the Chinese Academy of Sciences. The LUCC was characterised by a continuous decrease of arable land and continuous increase of waters and construction land. The LUCC was obviously concurrent with the implementation of related national policies. The transition to construction land was ever well controlled by ‘Notice regarding the further strengthening of land management and arable land protection’ promulgated in 1997. However, it flourished again with the ‘Rise of Central China Strategy’ taking effect since 2006. The transition of construction land to others reflects an uncommon trend, which must be strengthened with the strict implementation of the overall plan, which imposes a limited acreage quota of construction land to each district. The policies were quite contradictory to the transition of waters. LUCC related to waters is most active, which was driven by both natural forces and national policies. Just after the devastating flood of 1998, the state council of China put forward the Green Policy to govern the major rivers. As to the study area, it is mainly to ‘push over dykes to let flood through and return farmland to lakes’. In 2004, the Grain Direct Subsidy Policy was implemented, which, along with the surge in the price of rice, resulted in a strengthening trend of conversion of ponds to paddy fields.     

烟气脱硫脱氮技术综述

本文主要介绍了烟气中二氧化硫和氮氧化物的脱除技术。目前二氧化硫的脱除技术有燃烧前脱硫、燃烧中脱硫和燃烧后脱硫三种。燃烧后脱硫技术又称为烟气脱硫技术。烟气脱硫技术有湿法、干法和半干法三种,其中湿法应用最为广泛。NOx的控制技术有选择性催化还原法、选择性非催化还原法、烟道气循环法、低NOx燃烧器法。其中,选择性催化还原法是应用最多、技术最成熟的一种烟气脱氮方式。此外,还有SO2和NOx的一体化脱除技术。     

石油安全指标体系与综合评价

为科学评价我国石油安全的程度,从国内资源禀赋、国内生产能力、国际市场可得性和国家应急保障能力等4个方面,设计了石油安全评价指标体系。采用德尔菲法、主成分分析法,选取储采比、储量替代率、石油消费对外依存度、石油进口集中度、国际原油价格和国内石油储备水平等6个个指标,构成一个新的综合指标:石油安全度,用其对我国石油安全形势进行定量评价。将石油安全度的安全警戒划分为五级:I级1～0.8,基本安全;II级0.8～0.6,弱安全;III级0.6～0.4,不安全;Ⅳ级0.4～0.2,很不安全;V级0.2以下,严重不安全。1993-2004年,我国石油安全度为0.54～0.75,处于弱安全到不安全之间。     

金属矿井主扇反风技术分析及数值模拟研究

立足于现有的计算流体力学方法,提出了对轴流式风机反风的数值仿真模拟。运用CFD软件Fluent对轴流式风机正反转都进行了三维数值模拟,选用K40-4-15型轴流风机作为研究对象,重点研究了轴流式风机的反风性能以及叶片安装角、叶型拱度和转速对其反风量的影响。模拟结果为提高轴流式风机的反风量提供了科学的依据。