深水型湖泊底泥NH4＋-N吸附的环境因子影响实验研究

以福州市山仔水库为例，通过对底泥NH4＋N吸附的模拟实验，分析了环境因子对底泥NH4＋-N吸附特性的影响及其原因。得出了温度、上覆水本身NH＋-N浓度和底泥粒径对底泥NH4＋-N吸附的影响曲线。为深水型湖泊底泥疏浚和富营养化治理提供依据。     

红枫湖、百花湖水库底质总磷负荷及其对湖泊富营养化贡献

对红枫湖、百花湖水库沉积物及其磷储量的调查统计,结合近年来两湖频繁发生的水污染事件,研究了红枫湖、百花湖水库沉积物总磷含量分布及其总磷负荷对湖泊富营养化贡献,探讨了红枫湖、百花湖水库沉积物的释磷潜力。结果表明,红枫湖、百花湖沉积物中总磷含量分布由表层到底层进行递减堆积,沉积物已成为两湖近年来湖泊磷富营养化的内源。到2006年红枫湖、百花湖沉积物干重累积量分别为240.7万t、73.78万t,平均总磷含量为0.163%、0.174%,总磷储量已达3 924 t、1 284 t。当外界环境因素推动时,沉积物发生搅动造成磷大量释放,是两湖频繁发生湖泊大面积水华污染事件的主要原因。     

不同湖泊水华发生机制研究进展

目前,世界各地湖泊水华的暴发越来越严重,对人类健康和生态系统有重大危害.本文调研了国内外典型湖泊水华的相关研究成果,从湖泊所属地理位置、气候带、受人类活动干扰强度、主要水华发生藻种和主控环境因子等不同角度进行了总结和分析,揭示了不同类型的湖泊水华特征和发生机制.最后以我国太湖为例,总结已有的研究成果,结合近几年太湖水华和水环境实测数据的分析结果,归纳了太湖水华的主要影响因子,包括Chl-a、TN、TP、COD、温度、风速六个指标,其中Chl-a、COD能指示说明水华的程度,TN、TP是营养盐状况的代表,温度和风速是水华发生的主要气象因子,并定量分析了水华程度和影响因子之间的关系,为水华的预警、预测和评价提供基础和支持.     

福州二水源--山仔水库底泥磷的赋存形态

通过实验,对福州二水源--山仔水库低泥中磷的形态作了定性和定量分析,得出了底泥中各形态磷的垂向变化趋势和影响底泥磷释放的主要形态-铁磷,并分析了各形态磷对底泥磷释放的贡献,对研究山仔水库富营养化有重要意义.     

东洞庭湖底泥的释磷特性

为了研究东洞庭湖底泥的释磷规律,考察了pH值、温度、溶解氧、扰动等环境因子对湖泊底泥中磷释放的影响.研究结果表明,水体pH值在7左右时,上覆水体中磷浓度最小,降低或升高pH值都能使磷浓度增加;环境温度越高,上覆水体中磷浓度也越高,但变化趋势不明显;在相同条件下,厌氧环境时上覆水体中磷浓度是好氧时的5.56倍;而扰动对磷释放的影响仅是有限的短期效应.各影响因素中以溶解氧对底泥释磷影响最为显著.     

江西省不同营养类型湖泊底泥沉积物对磷的等温吸附特征

利用TLI方法将江西省18个湖泊分为中营养型和轻度富营养型两类。在低范围初始磷浓度和高范围初始磷浓度条件下,研究了两类湖泊底泥沉积物对磷的吸附等温热力学特征,并得出其相应的热力学参数特征值,研究结果表明:在低初始磷浓度条件下,两类湖泊对的磷等温吸附线符合Linear模型;在高初始磷浓度条件下,两类湖泊对磷的吸附等温线均能较好的符合Langmuir模型和Freundlich模型,显著水平(P0.05);中营养型湖泊底泥沉积物对磷的最大吸附量Q_(max)、吸附效率m、沉积物本底吸附态磷NAP和磷吸附/解吸平衡浓度EPC_0分别为669.828～833.224 mg/kg、112.006～216.07 L/kg、15.274～25.177 mg/kg和0.071～0.225 mg/L,而轻度富营养湖泊底泥沉积物对磷的Q_(max)、m、NAP和EPC_0分别为718.027～856.822 mg/kg、124.310～148.910 L/kg、22.248～30.838 mg/kg和0.156～0.259 mg/L,从热力学参数的大小方面分析,中营养型湖泊Q_(max)、NAP、EPC_0、K的值均小于轻度富营养型湖泊;中营养型湖泊底泥沉积物的Q_(max)、NAP、EPC_0与TP、IP、Fe/Al-P与OP含量相关性较好;而轻度富营养型底泥沉积物Q_(max)、NAP、EPC_0与IP、Fe/Al-P含量相关性较好,Q_(max)、NAP和EPC_0与沉积物污染程度有关。该研究结果为进一步揭示湖泊富营养化机制提供数据上的支撑。     

亚热带联和水库理化因子及浮游植物分布特征

在亚热带水库中,水体的理化因子影响着浮游植物的分布和数量。然而,浮游植物也会对周围环境进行反馈作用。广东联和水库自2012年以来,每年夏季都会爆发密集微囊藻的藻华。为了研究周围环境与水华之间的关系,以及探讨爆发水华藻种的来源,对联和水库的物理和化学因子,以及浮游植物的时空变化进行了调查。结果表明,在热分层时期,水体中的pH、溶解氧和叶绿素a浓度在垂直方向上具有显著变化。浮游植物群落组成也发生季节性变化。在冬季混合时期,浮游植物优势种为梅尼小环藻;而在夏季热分层时期,优势种则变为密集微囊藻。同时,对水库周围河流与村庄池塘进行了调查,没有发现爆发水华的密集微囊藻。但在坝前水库底部发现密集微囊藻的休眠种子。因此,密集微囊藻并不是来源于上游水体,而是来自于水库本身。密集微囊藻细胞被认为自建库以来就存在于库中,通过休眠来克服恶劣的生存条件。当温度和光照,以及营养盐浓度达到适宜条件,藻细胞开始大量分裂生长。此外,浮游植物的分布对水体中溶解氧含量和总磷含量的垂直分布也起一定影响。在一年的水库氮磷收支中,均有一定量的氮和磷滞留在库区,氮的输入主要来自于大气沉降和河流,磷的输入则主要来自于河流与沉积物。     

洋河水库“水华”发生的实验研究

本工作在洋河水库现场进行了“水华”发生的实验研究，采用以受控生态系统实验为主，结合对自然水体进行观测的方法，观察了从藻类增殖到“水华”形成及消失的全过程；定量研究了“水华”发生所需的条件。研究表明：水体的富营养状态是藻类异常增殖的主要原因，而藻类的异常增殖又是“水华”发生的前提条件。“水华”发生时水体表层所需的藻类生物量阈值为４８．０μｇＣｈｌａ／ｌ。气象因子引起的藻类聚集对于“水华”的发生具有诱     

蓝藻水华显著影响因子识别模型

根据蓝藻水华反演图判断蓝藻水华发生与否,进而构建了直接以蓝藻水华发生与否的指标为因变量,同时以水质、水文和气象3类共19个指标为自变量的蓝藻水华环境影响因子识别模型(Probit模型),并将该模型应用到太湖.经模型分析,识别出太湖蓝藻水华暴发的显著环境影响因子:气温和硝酸盐浓度与蓝藻水华暴发的概率正相关;风速、湿度和电导率则与水华暴发的概率负相关.将离散因变量模型(二元选择模型)引入蓝藻水华研究领域,对湖泊(水库)蓝藻水华暴发的预测和预防具有参考价值.     

竹银水库底泥氮磷含量调查与分析

竹银水库是珠海市库容最大的供水水库,在保障珠澳供水安全方面发挥着重要作用。通过对水库不同区域的底泥沉积物采样与分析,结果显示:5个监测点底泥沉积物中TN和TP含量较低,内源负荷较小。本次底泥沉积物调查分析是竹银水库水生态多因子监测及评价项目的重要一环,为全面评价竹银水库水生态健康状况奠定基础。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

A computer generator for randomly layered structures

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

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

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。     

Exciton Seebeck in Molecular Systems

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     

Achieving Unusual States of Matter Under High Pressure

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     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

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.     

An improved R-tree based on childnode''s probability

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).     

Integrating GIS Web services based on mediating architecture

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.