氢自养反硝化细菌SY6的反硝化特性研究

从水库底泥中分离出1株氢自养反硝化细菌SY6.以氢自养反硝化菌株SY6作为研究对象,分析了氢气作为电子供体时,氢自养反硝化细菌SY6生物脱氮途径及生长增殖规律,考察了不同环境因子对菌株SY6生物脱氮性能的影响.结果表明,30℃时菌株反硝化效率最高,此时NO-3的去除率达到100%;在p H值为6—7的中性偏酸环境,菌株反硝化效果最好,NO-3的去除率为100%.不同的C/N对反硝化效果的影响很小,以Na HCO3作为碳源反硝化效果优于以CO2作为碳源.     

异养菌株HNR脱氮性能

从膜生物反应器中分离出一株异养型高效脱氮细菌,该菌为革兰氏阴性杆菌,命名为HNR.经16S rRNA测序,该菌株属于Acinetobactersp.菌属.以氯化铵为惟一氮源,探讨了不同碳源、pH值、温度及碳与氮质量分数之比w(C/N)对HNR菌株脱氮性能的影响.实验结果表明:以葡萄糖为碳源、pH值为8、温度为30℃、w(C/N)为10时,HNR具有最佳脱氮效果.在好氧条件下,当氨氮初始质量浓度为120 mg/L时,经过72 h的连续培养,其氨氮和总氮的去除率分别达92.5%和89.1%.通过气相色谱能检测到N2,但检测不到N2O.HNR不具有明显的好氧反硝化性能,表明HNR的脱氮途径可能与已报道过的异养硝化好氧反硝化脱氮途径有所不同.     

甲醇与葡萄糖为碳源在反硝化过程中的比较

在颗粒滤床反应器内 ,以葡萄糖或甲醇为碳源 ,碳源充足时 ,均可以比较完全地去除硝酸盐 ,但以葡萄糖为碳源的最佳碳氮比较甲醇为碳源高得多 ,为 6∶1～ 7∶1 (C6H1 2 O6∶NO-3 N)。当碳源不足时 ,反硝化过程存在亚硝酸盐积累现象 ,且葡萄糖为碳源时积累更严重。以CH3OH为碳源进行的反硝化速率较以C6H1 2 O6 为碳源的快得多 ,在相同条件下快 3倍。在本实验条件下 ,反硝化过程表现出 0级反应特征 ,k (CH3OH) =1 60mg/L·h ,k(C6H1 2 O6) =42mg/L·h。     

低C/N比污水脱氮技术研究

生物脱氮技术是通过硝化和反硝化菌来实现氮的去除,而充足的碳源是反硝化菌高效脱氮的关键,研究表明,只有当C/N〉4时才可给反确化细菌提供适量的碳源,使得生物脱氮正常进行,达到TN达标排放。针对低C/N比污水传统生物脱氮碳源不足、脱氮效率不高等问题,文章阐述了几种有效处理低C /N比污水的组合工艺、连续流一体化间歇曝气膜生物反应器（IMBR）等新工艺及分段进水、外加碳源等强化措施,并对这些技术和工艺的应用情况进行了简要分析。     

水力负荷和C/N比对玉米芯固体碳源SND处理低碳城市污水的影响

采用玉米芯填料固体碳源生物膜反应器,应用同步硝化反硝化(SND)技术处理低碳氮比城市污水,考察不同水力负荷和C/N比对系统脱氮效果的影响,并对玉米芯挂膜前后表面形态进行分析.结果表明,在水力负荷为0.045 m3·m-2·h-1时,NH+4-N和TN平均去除率分别为92.16%和91.18%;当进水C/N比控制在0~12时,出水CODCr浓度均在50 mg·L-1以下,TN平均去除率在79.63%以上,脱氮效果随进水C/N比的增加而提升;通过电镜扫描表明玉米芯是一种较好的固体碳源生物膜反应器填料,适合低碳氮比城市污水的脱氮处理.     

一株好氧反硝化菌的鉴定及脱氮特性研究

以筛选分离得到的好氧反硝化菌HG-7为研究对象, 经过16S rRNA同源性分析, 初步鉴定该菌株为假单胞菌属(Pseudomonas sp.)。对菌株HG-7反硝化功能基因的扩增结果表明, 菌体HG-7内存在好氧反硝化功能基因napA和nirK, 证实该细菌为好氧反硝化细菌。对菌株的脱氮特性和影响因素的研究表明, 以硝酸盐氮为氮源时, 菌株的最适碳源为乙酸钠和丁二酸钠, 最佳C/N比为6~10, 最适宜的温度范围为26~30℃。在上述条件下, 菌株HG-7的好氧反硝化活性较高, 48小时内对100 mg/L硝酸盐氮的去除率可达98%, 且在反应过程中亚硝酸盐氮积累量较低。以亚硝酸氮为唯一氮源时, 低浓度条件下可实现100%的氮素去除率; 高浓度条件下, 脱氮速率则受到明显的抑制, 对91.4 mg/L的亚硝酸盐氮氮去除率约为40%。因此, 将该菌株应用于废水的脱氮处理, 可实现氮素的有效去除, 具有潜在的应用价值。     

污水处理中微生物反硝化脱氮过程及代谢规律

微生物同化、异化反硝化均依赖碳源,且同化C/N为23远高于异化C/N。污水系统中反硝化菌多为兼性厌氧菌,其反硝化效果受DO、碳源种类、温度等因素影响较大。DO与NO3--N为竞争关系,DO存在会抑制反硝化,但高DO有利于反硝化菌的生长。不同碳源反硝化所需C/N不同,污水为碳源时所需的C/N约为4.0-5.0,污泥内源呼吸时反硝化C/N最低为2.9-3.2,但其反硝化速率仅为利用VFA时的1/10。常见VFA如甲醇、乙酸等C/N为3.1-4.1。反硝化过程中还应注意温室气体N2O逸出等问题,偏酸性及较高DO会导致反硝化过程N2O积累与逸出。     

不同固态碳源去除地下水硝酸盐的试验研究

文章研究不同条件下锯末、玉米芯及黄秋葵秸秆作为微生物反硝化碳源时的脱氮性能,筛选出优质固体碳源和反应条件,为氮污染去除现场应用提供参考。试验结果表明:在不同碳源用量(0.25、0.50、1.00、2.00g)条件下,3种碳源的硝酸盐去除率均表现出随着用量增加呈先上升后下降的趋势,其中玉米芯比其他2种碳源的脱氮效果更好,当玉米芯的用量为1.00g时硝酸盐的去除率最高,达98.3%;不同温度条件下的优化试验结果表明,35℃时玉米芯组的微生物对硝酸盐的反硝化效果最好,其去除率达98.5%。在地下水动态模拟试验中选用玉米芯为填充介质,其去除率与进水NO_3-N的初始质量浓度之间有很好的相关性,初始质量浓度升高,去除率降低但去除量升高,且随着进水流速减小,NO_3-N的去除率升高。     

低温对固体碳源填充床反硝化的影响

为固体碳源反硝化工艺的实际应用提供理论和技术参数,采用一种淀粉基类的可生物降解聚合物作为反硝化微生物的固体碳源和生物膜载体反硝化脱氮,主要考察了低温对填充床反硝化性能的影响.试验结果表明: 8～10℃的低温下,进水硝酸氮浓度在60～80 mg·L-1之间时,反硝化速率为2.5～4.5 mg·(L·h)-1, 去除率低于20%, 均比常温下有明显的降低;在水力负荷9～12 cm·h-1之间时,反硝化速率与水力负荷成正比;在10～15 ℃范围内,温度对反硝化率的影响比常温时要大,温度常数K=0.046.     

以甘油为碳源去除地下水中硝酸盐的试验研究

文章研究了以甘油为碳源的生物反应器,在相同的硝酸盐氮浓度和甘油浓度梯度下,分别投加纯反硝化菌种和土著反硝化菌种时,去除地下水中硝酸盐的情况。结果表明,投加反硝化菌的反应器启动较快,去除效果较好,硝酸盐氮去除率可达到97.7%以上。在碳源充足的情况下,脱氮时效性差异不明显,反应器pH在7.0±0.2范围内波动。该研究旨在...     

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).     

An Index mechanism for multi-scale view in spatial databases

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.     

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.