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1.
以南京市某净水厂的沉淀池、滤池污泥为研究对象,采用Udden-Wentworth标准将净水厂污泥粒径分为4级,即3.9μm,3.9~63μm,63~250μm和250μm。3.9~63μm粒径的污泥分别占沉淀池和滤池污泥总体积的55%和73%;滤池污泥的有机质含量比沉淀池的高,在各粒径组分中的含量范围分别为12.64%~15.11%和8.09%~10.27%;沉淀池和滤池污泥中共检出14种多环芳烃,总质量分数平均值分别为556.59 ng/g和468.44 ng/g,其中2环和3环PAHs的质量分数之和为4环和5环的2~3倍,PAHs在各粒径组分中的质量分数分布与有机质的质量分数分布一致,PAHs在250μm和63μm的粒径组分中的质量分数较高,在63~250μm粒径组分中质量分数相对较低;污泥粒径和有机质质量分数影响污泥中金属浓度的分布,沉淀池和滤池污泥中8种金属(Al,Fe,Cd,Cu,Cr,Pb,Mn和Zn)在63μm的粒径组分中质量分数相对较高。  相似文献   

2.
采用高效液相色谱法测定贵阳市道路地表灰尘中PAHs的含量,并对其分布特征及来源进行解析.结果表明,贵阳市道路地表灰尘中PAHs主要为化石燃料的燃烧所致,高环PAHs含量较高.工业区和重要交通干道的ΣPAHs含量最高,公园最低,在不同粒径道路地表灰尘中∑PAHs在630.3~1 870.1μg/kg之间,∑PAHs均值为1 154.5μg/kg,∑PAHs浓度最大值及质量负荷率的最大值出现在粒径范围0.074~0.150mm灰尘样品中.  相似文献   

3.
水化法制备超细Mg(OH)2的研究   总被引:5,自引:0,他引:5  
以菱镁矿为原料,采用水化法制备Mg(OH)2超细粉体,研究了水化温度、添加剂对水化产物颗粒大小的影响。结果表明:NaOH为添加剂,水化温度70℃所得产物颗粒最细,产物d50为0.94μm;NaOH作添加剂时,随OH^-浓度增加,产物粒径减小,当OH浓度为1moL/L,所得产物粒径最小,其d50为0.94μm,但随OH浓度的进一步增加,颗粒有增大趋势;氨水作添加利时变化趋势与NaOH作添加剂类似,当OH^-浓度为1.55moL/L时.产物粒径最小,d50在1.6μm左右。  相似文献   

4.
通过溶剂超临界CO2雾化萃取法制得了乙基纤维素微粒.研究了溶液喷口流速、溶液浓度、温度、压力对颗粒粒径及其粒径分布的影响.结果表明,改变工艺参数,可在较大范围内调控微粒大小,所得微粒平均粒径为0.64~10.83μm.随着温度和溶液浓度的增加,颗粒粒径及其粒径分布增加;随着压力和溶液喷口流速的增加,颗粒粒径及其粒径分布减小.  相似文献   

5.
利用GC-MS对上海市多环芳烃(PAHs)潜在的污染源成分谱特征进行了定量分析。结果表明,工业区路面尘中PAHs含量最高值均分布在土壤63~125μm粒径中,主要以中高环Phe、Fl、Pyr、Chry、B[b+k]F和Ba P为主;建筑工地土壤与路面尘中PAHs分布特征相似,主要以Phe、Fl、Pyr和Chry为主;秸秆在不同燃烧条件下PAHs产生量不同,但PAHs组分特征相同;卡车、客车和小汽车中PAHs含量分别为56μg/g,47.2μg/g,529.1μg/g。小汽车尾气中以高环PAHs为主,卡车和客车以低环为主;油烟中Ba P的平均含量为38 ng/g,单体PAH以Phe、Fl、Nap和Pyr为主。烤肉中PAHs的含量为6.7μg/g。  相似文献   

6.
燃烧过程中铅颗粒粒径分布的实验研究   总被引:2,自引:0,他引:2  
使用高3.4m、内径0.15m的一维炉实验台,对燃烧中铅颗粒的粒径分布进行实验研究。铅元素以醋酸铅溶液的形式通过空气雾化引入到燃烧液化石油气的炉膛中。使用切割粒径从0.48~12.63μm的8级A ndersen撞击器和切割粒径从0.030~10.0μm的12级静电低压撞击器(ELP I)进行采样,同时对铅颗粒物的质量浓度粒径分布和数量浓度粒径分布进行了测量。使用场发射扫描电镜(FESEM)对铅颗粒微观形貌进行了观察。结果表明:在质量方面,铅颗粒主要集中在亚微米区间,质量浓度的峰值在0.2~0.6μm之间;在数量方面,铅颗粒主要集中在0.03~0.4μm区间,数量浓度的峰值在0.2~0.3μm之间。  相似文献   

7.
使用高3.4m、内径0.15m的一维炉实验台,对燃烧中铅颗粒的粒径分布进行了实验研究。铅元素以醋酸铅溶液的形式通过空气雾化引入到燃烧液化石油气的炉膛中。使用切割粒径从0.48~12.63μm的8级Andersen撞击器和切割粒径从0.030~10.0μm的12级静电低压撞击器(ELPI)进行采样,同时对铅颗粒物的质量浓度粒径分布和数量浓度粒径分布进行了测量。使用场发射扫描电镜(FESEM)对铅颗粒微观形貌进行了观察。结果表明,在质量方面,铅颗粒主要集中在亚微米区间,质量浓度的峰值在0.2~0.6μm之间;在数量方面,铅颗粒主要集中在0.03~0.4μm区间,数量浓度的峰值在0.2~0.3μm之间。  相似文献   

8.
兰州市冬季大气PM10的微观形貌和粒度分布   总被引:4,自引:0,他引:4  
利用高分辨率场发射扫描电镜(FESEM)和图像分析技术研究了兰州市区(东方红广场)2005年冬季大气可吸入颗粒物(PM10)的微观形貌、数量-粒度和体积-粒度分布特征。结果表明,兰州市冬季大气PM10主要包括燃煤飞灰、烟尘集合体、矿物和未知颗粒四种类型,其中燃煤飞灰在数量上占优势(61.7%),烟尘集合体和矿物颗粒在体积上占优势(43.6%和41.4%)。在数量-粒度分布上,粒径小于0.3μm的PM10占总颗粒物数量的78.6%,以燃煤飞灰为主(55.7%)。在体积-粒度分布上,粒径1~5μm之间的PM10占总体积的53%,主要是矿物颗粒和烟尘集合体(31.1%和19.6%)。综上可见,2005年冬季兰州市大气污染以燃煤污染为主,是今后大气环境防治中的主要控制对象。  相似文献   

9.
李爱贞 《山东科学》1991,4(2):56-61
对济南市东郊工业区大气悬浮颗粒物的粒径分布和形状特征的分析表明:该地区粒子谱分布为Junge分布;粒子的质量中值直径为3~4μm;1μm以上的粒子质量粒谱分布呈对数正态分布;粒径在2μm以下的细粒子的质量浓度只占总量的20%~30%。对不同粒子形状的研究表明:冬季,由于能源燃烧排放的颗粒物占总量的70%。  相似文献   

10.
在乙醇 水介质中通过分散聚合方法合成了单分散性好,交联度高,粒径在3~5μm的聚甲基丙烯酸甲酯微球,考察了单体、引发剂、稳定剂、交联剂浓度和介质配比对粒子粒径及其分布的影响.研究结果表明,交联剂、引发剂浓度增大,聚合速率增大,粒径呈增加趋势;稳定剂浓度增大,粒径减小.粒径在单体浓度为100g·L-1时出现一个最小值.初步探讨了聚合方法对粒径、粒径分布及粒子形态的影响.  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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