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...     

新型复合碳源去除工业综合园区废水中硝酸盐试验研究

以传统醋酸钠碳源为对照,开展了一种新型复合碳源对工业综合园区废水中硝酸盐去除性能的研究。主要通过考察搅拌转速、反应时间、碳源浓度与硝酸盐氮浓度等因素的影响,以确定在获得同等硝酸盐去除效果下,两种碳源投加量关联关系,并在天津某工业园区污水处理厂进行工程应用验证。试验结果表明:在获得等量硝酸氮的去除量下,新型复合碳源投加量可比醋酸钠碳源节约30%,在同等碳源投加下,新型复合碳源可比醋酸钠增加50%硝酸盐去除量;工程应用结果表明新型复合碳源节省量预计可达40%,展示出该新型复合碳源具有替代醋酸钠碳源的潜能。     

碳源、C/N和温度对生物反硝化脱氮过程的影响

生物反硝化法是去除水体中硝酸盐的有效方法。鉴于生物反硝化过程中有机碳源不足的问题,选择甲醇、乙醇、葡萄糖作为反硝化碳源,研究它们对反硝化的促进作用;同时研究C/N比以及温度对反硝化过程的影响。结果显示:甲醇、乙醇和葡萄糖作为反硝化碳源时,均可获得较高的硝酸盐氮去除率。以乙醇为碳源时,反硝化速率进行的最快,硝酸盐氮去除率高,中间副产物亚硝酸盐氮和氨氮积累少,是最优的反硝化碳源;C/N比对反硝化过程影响显著,C/N比越高,脱氮速率越快;另外温度对反硝化也有着重要的影响,在25℃、35℃时的脱氮效果远好于10℃时的脱氮效果。     

不同外碳源对生物反硝化影响的研究

针对城镇污水处理中碳源不足影响系统脱氮能力的问题,分别以乙酸钠、葡萄糖、甲醇作为外源性碳源,考察各碳源对活性污泥脱氮能力的影响。研究结果表明,在乙酸钠投加量分别为50、100、200mg/L条件下,NO3--N去除率分别为68.8%、85.8%、100%;在葡萄糖投加量为50、100、200mg/L的条件下NO3--N去除率分别为47.3%、64.3%、76.2%;甲醇有一定的滞后性,在投加初期对反硝化能力并没有明显的促进作用。由试验结果可知,乙酸钠可以作为高效外源性碳源用作城镇污水脱氮除磷。     

碳源对地下渗滤系统脱氮及产生N2O的影响

生活污水经沉淀预处理后投配到地下污水渗滤系统(SWIS)中进行深度脱氮处理.考察了在SWIS基质中添加有机碳源对脱氮效果、脱氮微生物活性及N₂O产生量和转化率的影响.研究结果表明:碳源的添加有利于促进微生物的反硝化作用,但过量添加会促进其他菌群的生长而抑制脱氮菌群的优势活性,从而削弱系统的脱氮能力.当有机质质量分数由2.0%提高到9.5%时,SWIS对污水中COD、氨氮及总氮平均去除率分别降低了10.9%,19.5%和24%;N₂O产率和转化率均随着碳源添加量的增加而下降.相关分析表明,硝化细菌、反硝化细菌数量对数值分别与N₂O转化率呈显著正、负相关关系(R^○2分别为0.994及0.959),说明SWIS中微生物硝化-反硝化作用尤其上层硝化反应是N₂O产生的主要途径.     

补充植物碳源提高人工湿地脱氮效率

为解决有机碳不足抑制反硝化反应造成的脱氮效率低下的问题,向人工湿地系统中添加富含有机质的植物材料作为反硝化所需的有机碳源,根据玉米秸秆、稻壳、木屑及芦苇竿4种植物材料有机物释放规律及植物体分解对水质的潜在影响情况,确定芦苇竿为较适宜的植物碳源.采用垂直流人工湿地单元模型研究了补充芦苇竿对人工湿地脱氮效果的影响,初步确定了试验条件下芦苇竿的适宜添加量范围为0.47～1.09 kg/m2.硝态氮的沿程变化规律表明,芦苇竿释放出的有机物提供了反硝化所需的有机碳,提高了人工湿地的脱氮效果.     

利用人工湿地去除饮用水硝酸盐氮研究

文章采用砂砾与土壤层构建垂直流人工湿地栽培芦苇和水花生,通过在同种基质上栽种相同数目的芦苇和水花生,以高质量浓度硝酸盐氮的配水进行浇灌,研究了这2种净水植物对饮用水中硝酸盐氮的脱除效果,并考察了净水效果较好的水花生的种植密度对其人工湿地脱氮的影响。研究表明,在人工湿地系统中,脱氮主要靠植物吸收,同时也存在硝化-反硝化途径;水花生和芦苇均能将饮用水中的硝酸盐氮有效脱除,在15d内,当进水硝酸盐氮质量浓度为50mg/L时,硝酸盐氮的去除率分别为94.0%和83.9%,当进水硝酸盐氮质量浓度为100mg/L时,硝酸盐氮的去除率分别达到96.8%和88%;相同条件下水花生去除硝酸盐氮的效果比芦苇更好;增加湿地植物的种植密度可获得更好的脱氮效果。     

硝酸盐氮污染地下水原位修复的试验研究

在北京北天堂非正规垃圾填埋场进行硝酸盐氮污染地下水原位修复试验研究。通过抽水试验、示踪试验和碳源投加试验,分析了对污染地下水的原位修复能力及效果。试验结果表明,试验获得了指导后续地下水修复试验及数值模拟预测的水文地质参数,试验场区的潜水含水层渗透系数为195.3 m/d,导水系数为781.3 m2/d,给水度为0.167°。在碳源投加试验运行初期,地下水中的硝酸盐氮去除率就已达到45%以上,投加碳源后对地下水硝酸盐氮反硝化作用有很好的强化效果。试验分析方法和研究成果为类似试验研究积累了成功经验,可为地下水原位修复工程应用及推广提供借鉴与参考。     

复合固相碳源材料强化生物绳脱氮效果

总氮超标的微污染水体中有机碳源较少,投加外部碳源可促进反硝化脱氮,固体碳源因能克服传统碳源缺点而备受关注.以农业废弃物玉米芯和高分子材料作为碳源,以聚乙烯醇和海藻酸钠作为骨架载体,利用交联法制备2种复合固相碳源PSPC-Ⅰ和PSPC-Ⅱ,并研究释碳特性及强化生物绳脱氮效果.结果表明, 28 d内两种固相碳源持续释碳且未达到释碳平衡,最高释碳量分别达6.3和8.7 mg/g (以溶解性有机碳计);三维荧光结果显示释放碳源以微生物易降解的可溶性微生物代谢产物和芳香蛋白类物质为主;与不投加碳源的生物绳(生物量200 ng/g,以三磷酸腺苷计)相比, 2种固相碳源均显著增加了生物绳挂膜生物量(PSPC-Ⅰ和PSPC-Ⅱ的生物量分别为400～600和300～500 ng/g,以三磷酸腺苷计); 2种固相碳源均显著增强了反硝化作用,对照组未脱氮, 2种固相碳源脱氮率达80.4%和75.0%.     

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。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that