乌鲁木齐市MODIS气溶胶光学厚度与PM10浓度关系模型研究

为了建立乌鲁木齐市近地面PM10浓度监测的关系模型,利用乌鲁木齐市2013年3—11月、2014年3—11月MODIS AOD产品与同期地面观测的PM10质量浓度进行相关分析,结果表明二者直接相关程度较低(r=0.433,p0.01);然后以WRF模式模拟的大气边界层高度及地面观测的相对湿度数据对AOD进行垂直、湿度订正后,二者相关性得到较大程度提高(r=0.630,p0.01);按照季节分类统计和订正春、夏、秋季的相关系数r分别为0.779、0.393、0.523,均大于统计学上99%的置信度要求,其中春季的订正最为有效,可用性更高;最后,建立全年和各季AOD-PM10最优拟合模型并反演乌鲁木齐市地面PM10质量浓度,全年和三季的反演结果与实测数据的相关系数分别为0.757、0.748、0.652、0.715(p0.01);同时基于卫星遥感AOD反演得到的PM10质量浓度的空间分布与AOD呈现出整体的一致性,并且3个季节AOD平均值表现为:春季秋季夏季.证实了卫星遥感AOD经过垂直和湿度订正后,可以作为辅助监测乌鲁木齐市PM10地面浓度分布的一个有效手段.     

Experimental investigation of solar still with opaque north triangular face

Developing a compact, simple, and productive solar still is a main challenge. This paper describes a simple modification of the solar still that significantly enhances its productivity. A laboratory scale of modified single effect double slope glass solar still with the opaque triangular north wall has been developed and tested for enhancement of productivity in sunny days of the summer season in the month of April. The experiments on still have been carried out under three levels of water depths from 1 to 3 cm and compared it with the performance of conventional still of double slope single effect solar still of the same size. It is clear from the observations that opaque type still gave maximum distillate of 1793 ml at 1 cm depth of water while conventional still could produce only 1519 ml for the same depth of water. Also, for 2 and 3 cm depth of water, the opaque type still found to be more productive than conventional double slope solar still. As the former produced 1532 and 1464 ml while the latter produced 1328 and 1235 ml, for 2 and 3 cm depth of water, respectively.     

Summary of efficacy evaluations using aerially applied Gypchek® against gypsy moth in the U.S.A.

Abstract

Gypchek^®, the gypsy moth (Lymantria dispar L.) nucleopolyhedrosis virus product, is manufactured by the United States Department of Agriculture (USDA) Forest Service, and Animal and Plant Health Inspection Service under controlled conditions in a laboratory strain of gypsy moth larvae. Gypchek was registered with the U.S. Environmental Protection Agency in 1978 as a general use pesticide to control gypsy moth. This product has been the subject of intense research and development targeted toward maximizing efficacy while minimizing the cost of production and application. The current Gypchek tank mix is applied at 1.25 × 10¹²occlusion bodies (OB's) per hectare for each of two applications (3‐days apart) at 18.7 litres/ha per application.     

杭州市河道底泥重金属污染评价与环保疏浚深度研究

重金属是河道底泥疏浚要控制的重要污染物,而疏浚深度是生态疏浚工程中需要确定的关键参数.本文以杭州经济技术开发区河道为研究对象,共采集18处底泥柱状样,采用土壤背景值、土壤环境质量二级标准值、变异系数和相关性分析方法对底泥中Cu、Zn、Pb、Cd、Ni、As的污染状况进行了评价,同时分析重金属总量和有效态含量在垂向上的变化特征,并引入地累积指数法对各深度底泥中的重金属进行累积性评估,利用本文提出的临界累积深度方法来确定合理的环保疏浚深度.结果表明,河道表层底泥中Cu、Zn、Pb、Cd、Ni、As的平均含量分别为165.16、342.40、55.34、3.61、34.06、36.70 mg·kg-1,Cd、Cu、As、Zn的有效态含量分别为0.007、3.37、0.095、20.76 mg·kg-1,重金属总量均超过了杭嘉湖平原土壤背景值,其中Cd污染最为严重.各重金属元素在底泥中的变异系数为0.29~2.39,空间分布并不均匀.重金属总量和有效态含量随底泥深度的增大整体呈下降趋势,但受不同时期人类活动污染及河道整治影响而呈不规则变化.各重金属元素的富集程度为CdAsZnPbNiCu,其中,Cd污染等级为2~6级,污染程度为中度污染至极强污染.利用临界累积深度方法推算得到研究区域河道底泥环保疏浚深度为0~0.9 m.     

基于拉曼散射的分布式光纤定温与差温探测方法

基于拉曼散射的分布式光纤测温系统应用于火灾监测有独特的优势,弥补了传统感温探测器的不足。介绍了基于拉曼散射的测温原理及基于光时域的空间定位原理,并进行了火灾预警实验,实验结果表明当建筑物高度在一定范围内,基于拉曼散射的分布式光纤测温系统可以很好地实现火灾预警功能。     

北京市北神树生活垃圾填埋场产甲烷菌的群落结构和演替规律

产甲烷菌是填埋场稳定化的关键微生物.以北京市北神树垃圾填埋场为采样地,钻井采集了填埋深度6~36.1 m,填埋时间2~15 a的垃圾样品.采用PCR检验其中产甲烷菌的种类,并基于QPCR技术获得的数据,研究了各类产甲烷菌随时间和深度的数量变化,及其与垃圾化学性质之间的关系.发现堆体内有机质含量基本稳定,p H呈弱碱性,符合产甲烷阶段的化学特性.检测出两类乙酸营养型产甲烷菌(Methanosaeta和Methanosarcina),一类氢营养型产甲烷菌(Methanobacterials).随着填埋时间的延长,产甲烷菌呈现出先升高后下降的趋势,填埋9 a以上的垃圾中产甲烷菌群落结构趋于稳定.乙酸营养型的Methanosarcina为优势类群.三类产甲烷菌的含量与挥发性脂肪酸含量显著相关,与各类大分子有机质含量相关性很弱或不相关,表明产甲烷菌的数量受底物含量的影响,而在填埋2 a以上的垃圾中,大分子水解、发酵等作用对产甲烷菌影响微弱.     

Secchi Disc Relationships1

ABSTRACT: The problem of estimating bulk light extinction coefficients in surface water impoundments is examined. It is shown that the bulk extinction coefficient can be accurately estimated from the Secchi disc depth. In addition, the equation derived is significantly different from that derived by Poole and Atkins in 1929. This empirical expression for the extinction coefficient is then used to develop a semiempirical expression for the euphotic depth as a function of the Secchi disc depth.     

Design of unsurfaced roads constructed with large-size shredded rubber tires: a case study

Stockpiles of scrap tires are serious fire hazard, public health hazard, and an environmental burden. The construction of road embankments, using tire shreds as a lightweight fill, can consume large quantities of scrap tires and has certain engineering benefits. All the previous research focused on small size tire shreds (3–6 in. size) in terms of its use in civil engineering applications and determination of the engineering/environmental properties. This research specifically focuses on large size tire shreds (12 in. size) and its direct comparison with the other sizes of the tire shreds to develop mechanistic-empirical practical design model and so that the use of tire shreds in road bases could be used on regular basis with enhanced reliability instead of on an empirical basis. The research also examines the potential environmental implications of the use of shredded rubber tires and the comparison of the short-term results with other long-term monitoring studies.     

OPTICAL CHARACTERISTICS OF NEW ZEALAND RIVERS IN RELATION TO FLOW1

ABSTRACT: Six years (1989–1994) of data from New Zealand's National Rivers Water Quality Network were used to characterize the optical water quality regime of river waters as regards: visual clarity (black disc visibility), turbidity, and light-absorbing aquatic humic material (referred to as ‘yellow substance,’ measured as light absorption at 440 nm). Quantitative relationships between optical water quality variables and flow in rivers are well-described by power law expressions. Visual clarity usually decreases strongly with increasing flow in individual rivers. There is a strong, inverse relationship between turbidity and visibility, but, because of differences between sites, turbidity is not a good general predictor of visual clarity (the attribute of real interest) in rivers. Yellow substance tends to increase with increasing flow, probably because during rainstorms, soil water high in yellow-colored humic material, rather than rain water or ground water, dominates discharge. Therefore, rivers are typically clear and low in humic matter at low flow, and turbid and yellow-colored at high flow.     

用于预应力筋长期实时应力监测的光纤传感测试技术研究

预应力筋是预应力混凝土结构中的关键受力构件,对其应力状态的监测具有重大意义。针对传统测试方法难以有效解决其应力分布测试问题的现状,提出基于光纤布拉格光栅传感测试技术的预应力筋长期实时应力监测方法。设计模拟张拉装置,并构建预应力钢筋的光纤光栅应变测试系统,进行模拟试验研究,其试验结果表明,该测试系统适合于预应力筋的工作环境,具有线性度高、重复性好,且不影响基体性能的特点。此外,针对预应力钢绞线的特殊结构和工作特点,提出具有温度补偿能力的锚端光纤布拉格光栅应力传感测试方案,并进行理论分析。研究结果验证了光纤光栅传感技术用于预应力筋应力测试的可行性,并为其实际工程应用奠定了基础。