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1.
本文利用公式ΔH=-0.1196n λ计算了H2在N2O内燃烧反应的火焰温度,计算值为3197K,与实际温度2923K较为接近.根据火焰温度,提出了H2在N2O内燃烧反应的机理,该机理为:(1)2N2O→N2 2NO;(2)NO hv→N· O;(3)N· NO→N2 O·;(4)H2 O·→H2O hv. 相似文献
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ZHOU HuaiYang WU ZiJun PENG XiaoTong JIANG Lei TANG Song 《科学通报(英文版)》2007,52(15):2140-2146
During DY105-17 cruise onboard the PJV "Da Yang Yi Hao" in 2005, methane concentrations in the water column above Logachev hydrothermal vent field were measured by applying stripping/trapping-gas chromatographic (GC) and the distinct methane plumes were detected. Results show that the background methane concentration within the Logachev area is from 1.05 nmol/L to 1.68 nmol/L, significantly higher than the background level of the Atlantic abyssal plain of 0.4-0.5 nmol/L, suggesting that hydrothermal venting is a major source of dissolved methane to the ocean. The highest anomalies of methane concentrations in the water column range from 7.14 nmol/L to 113.9 nmol/L and occur just at 180-500 m above the seafloor. The distribution of methane concentration and the structural characteristics of hydrothermal plumes are strongly influenced by the supply of underlying hydrothermal fluids, the mixing process of ocean bottom currents and the microbial oxidation. Furthermore, the differences in distribution of methane plume between the station MAR-CTD3 and the other stations indicate a probable unknown hydrothermal vent site nearby. There occurs high concentration of methane along with temperature and nephelometry anomalies, which strongly confirms that the subtle measurement of methane concentration in water column is one of the effective ways to locate active sites of hydrothermal venting. 相似文献
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《科学通报(英文版)》2007,52(15)
During DY105-17 cruise onboard the R/V "Da Yang Yi Hao" in 2005,methane concentrations in the wa-ter column above Logachev hydrothermal vent field were measured by applying stripping/trapping-gas chromatographic (GC) and the distinct methane plumes were detected. Results show that the back-ground methane concentration within the Logachev area is from 1.05 nmol/L to 1.68 nmol/L,signifi-cantly higher than the background level of the Atlantic abyssal plain of 0.4―0.5 nmol/L,suggesting that hydrothermal venting is a major source of dissolved methane to the ocean. The highest anomalies of methane concentrations in the water column range from 7.14 nmol/L to 113.9 nmol/L and occur just at 180―500 m above the seafloor. The distribution of methane concentration and the structural charac-teristics of hydrothermal plumes are strongly influenced by the supply of underlying hydrothermal fluids,the mixing process of ocean bottom currents and the microbial oxidation. Furthermore,the dif-ferences in distribution of methane plume between the station MAR-CTD3 and the other stations indi-cate a probable unknown hydrothermal vent site nearby. There occurs high concentration of methane along with temperature and nephelometry anomalies,which strongly confirms that the subtle meas-urement of methane concentration in water column is one of the effective ways to locate active sites of hydrothermal venting. 相似文献
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为了研究纳滤去除某市河水中微污染物生产饮用水的可行性,并筛选生产饮用水的最佳纳滤膜,采用四种纳滤膜DESAL 51 HL、DESAL 5 DL、UTC-20和UTC-60处理河水,研究其去除COD、UV254吸收值以及硝酸盐等微污染物效率,考察纳滤过程中水通量变化.试验结果表明,四种膜对COD和具254nm吸收值的有机物去除率在50%~95%之间,UTC-20去除有机物效率最高.DESAL 51 HL、DESAL 5 DL和UTC 60对无机物截留率在22%~65%之间,而UTC-20达到93%.UTC-20对不同原水中硝酸盐的去除率均大于70%.在短时间纳滤实验中,存在着不可逆的水通量减少,有轻度膜污染发生.结论UTC-20适用于处理有机污染和硝酸盐复合污染的地表水源生产饮用水. 相似文献
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提出了一种高效合成N,N1,N2,N3-四(4-甲基苯基磺酰基)季戊四胺的方法:即将季戊四溴与过量15%的对甲苯磺酰胺钠充分研磨混匀后置于反应釜中,再将反应釜密封后放入烘箱中于210 ℃下反应6-8 h,产率超过95%. 相似文献
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以2,2-联苯酸、联苯胺、乙二胺、对苯二胺等典型的含氮化合物为配体与Cu(Ⅱ)盐进行了水热反应合成了几种配合物CuLxL(N)y,其中L为2,2-联苯酸,L(N)为含氮化合物为配体,是联苯胺、乙二胺或对苯二胺等.通过元素分析,热重分析、IR分析等手段对配合物进行了表征;且研究了几种含氮配体在水热反应中的还原性.在水热条件下,NH2基团的还原性增强;以乙二胺中NH2的还原性最强,对苯二胺和联苯二胺次之,咪唑还原性最弱. 相似文献
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丁健华 《佛山科学技术学院学报(自然科学版)》2002,20(2):48-51
以负载了表面活性剂十二烷基硫酸钠 (SDS)的氧化铝做为吸附剂 ,用吡咯烷二硫代氨基甲酸铵 (APDC)作螯合剂 ,柱富集天然水中微量元素 ,火焰原子吸收光谱法 (FAAS)测定。对氧化铝负载 SDS及柱富集的条件进行了试验 ,并对光谱测定条件进行了优化。试验表明 ,在 p H为 1~ 6的范围内 ,SDS能被完全吸附在氧化铝的表面 ,形成胶束聚集体 ;p H在 2~ 7时 ,APDC螯合物能定量吸附在氧化铝负载柱上 ;在洗脱速率为 2 m L· min-1 时 ,用 c(HNO3 )为 5 mol· L-1 的 2 m L可定量洗脱 相似文献
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Increased marine production of N2O due to intensifying anoxia on the Indian continental shelf 总被引:8,自引:0,他引:8
Naqvi SW Jayakumar DA Narvekar PV Naik H Sarma VV D'Souza W Joseph S George MD 《Nature》2000,408(6810):346-349
Eutrophication of surface waters and hypoxia in bottom waters has been increasing in many coastal areas, leading to very large depletions of marine life in the affected regions. These areas of high surface productivity and low bottom-water oxygen concentration are caused by increasing runoff of nutrients from land. Although the local ecological and socio-economic effects have received much attention, the potential contribution of increasing hypoxia to global-change phenomena is unknown. Here we report the intensification of one of the largest low-oxygen zones in the ocean, which develops naturally over the western Indian continental shelf during late summer and autumn. We also report the highest accumulations yet observed of hydrogen sulphide (H2S) and nitrous oxide (N2O) in open coastal waters. Increased N2O production is probably caused by the addition of anthropogenic nitrate and its subsequent denitrification, which is favoured by hypoxic conditions. We suggest that a global expansion of hypoxic zones may lead to an increase in marine production and emission of N2O, which, as a potent greenhouse gas, could contribute significantly to the accumulation of radiatively active trace gases in the atmosphere. 相似文献
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Gases in the marine boundary layer in Fildes Peninsula, maritime Antarctica were sampled and analyzed for the first time. Sampling sites included areas covered by moss and lichen growth, penguin colonies and an area where scientific research stations are located. A total of 211 samples were analyzed for N2O concentrations, with an average of (321.33±3.07) nL/L. This is above the global average value of 314 nL/L. It is found that the N2O concentrations evidently increase during the summer months. Concentrations around the research stations are higher than at remote areas, indicating a potential source from human activities on the island. N2O concentrations at a large penguin colony on Barton Peninsula are the highest among the sampled areas. This may explain why N2O concentrations in Fildes Peninsula are higher than the global average. Our preliminary conclusions are that human activities and emissions from penguin dropping-amended soil and vegetation soil constitute the major sources of N2O in the maritime Antarctic atmosphere. 相似文献
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以配体4-烯丙氧基-2,6-二(N,N-二乙胺基甲基)吡啶与三苯基膦氯化钌配位化合物生成新的钌催化剂,催化苯乙酮氢转移反应。考察温度、碱强度、底物浓度及产物等对反应的影响。研究结果表明:在N2气氛下,82℃,苯乙酮、钌配合物和KOH的初始摩尔比为250∶1∶12,反应6 h,苯乙酮的转化率达到99.8%,该催化剂具有很好的催化活性和稳定性。 相似文献
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染化废水污染物种类多,毒性大、化学需氧量,ρ(CODcr)高,且大部分是生物难降解的污染物质,严重污染环境;利用铁炭在水中发生的微电解过程可有效去除染料生产废水的色度和化学需氧量ρ(CODcr),同时提高污水的后续可生化性.试验结果表明,微电解处理效果受填料组成、pH值、停留时间和混凝曝气等因素的影响;废水经过微电解处理后,ρ(CODcr)和色度分别从2 000 mg/L和2 048下降为860 mg/L和256,去除率可高达56%和75%;采用微电解-混凝法出水与采用单纯的石灰乳中和混凝沉淀法出水相比,ρ(CODcr)降低22.5%,可生化性提高18%. 相似文献
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黄孢原毛平革菌菌丝球对Pb2+的动态吸附及其洗脱 总被引:4,自引:0,他引:4
考察了黄孢原毛平革菌菌丝球对铅离子的动态吸附及其洗脱性能.实验结果表明,流速、温度、溶液pH值和初始浓度等因素对动态吸附有很大影响,饱和吸附量为20.19mg.g-1,比同样条件下的静态饱和吸附量(23.96mg.g-1)稍低.洗脱液流速和洗脱温度对洗脱速率有较大影响,洗脱率在90%以上(最高可达97.16%). 相似文献
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High rates of N2 fixation by unicellular diazotrophs in the oligotrophic Pacific Ocean 总被引:1,自引:0,他引:1
The availability of nitrogen is important in regulating biological productivity in marine environments. Deepwater nitrate has long been considered the major source of new nitrogen supporting primary production in oligotrophic regions of the open ocean, but recent studies have showed that biological N2 fixation has a critical role in supporting oceanic new production. Large colonial cyanobacteria in the genus Trichodesmium and the heterocystous endosymbiont Richelia have traditionally been considered the dominant marine N2 fixers, but unicellular diazotrophic cyanobacteria and bacterioplankton have recently been found in the picoplankton and nanoplankton community of the North Pacific central gyre, and a variety of molecular and isotopic evidence suggests that these unicells could make a major contribution to the oceanic N budget. Here we report rates of N2 fixation by these small, previously overlooked diazotrophs that, although spatially variable, can equal or exceed the rate of N2 fixation reported for larger, more obvious organisms. Direct measurements of 15N2 fixation by small diazotrophs in various parts of the Pacific Ocean, including the waters off Hawaii where the unicellular diazotrophs were first characterized, show that N2 fixation by unicellular diazotrophs can support a significant fraction of total new production in oligotrophic waters. 相似文献
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在无溶剂条件下,2-硝基-1,4-苯二氧基二乙酰氯与各种芳胺在室温下研磨可快速反应得到N,N′-二芳基-2-硝基-1,4-苯二氧基二乙酰胺(Ⅱa~Ⅱ1).该法与传统的溶液法相比具有无有机溶剂污染、反应速度快、产率高和后处理简单等优点. 相似文献
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四川盆地上三叠统隔气式气驱产水模式 总被引:1,自引:0,他引:1
通过四川盆地中部上三叠统裂缝性储层地质和开发动态的综合研究,认为气井产水能量主要受控于被水体分隔的天然气膨胀驱动,不同于一般气藏中的水体侵入。由于地层水和天然气的黏度存在显著差异,在较大压差开发条件下,具有高流度的被分隔空间天然气或多或少能够突破底部水体窜入井底采出,分隔空间的气水界面并非均匀下降,气窜是产出分隔天然气的主要方式。开发过程中的气水产量变化的影响因素包括气井所在的储气空间和被水体分隔的其他储集空间的天然气储量、分隔水体的体积和分隔阻力以及生产井的产量,这些因素的相互配置关系由井孔储层在裂缝系统中的位置所决定。提高气井排水能力、加大生产压差为分隔空间天然气突破水体创造条件,是产出分隔空间天然气提高有水气藏采收率的主要途径。 相似文献
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采用分子动力学方法研究了N2分子在强激光场作用下的经典轨迹,并应用了现在较优越的数值方法——辛算法来求解方程,这使计算结果更加令人信服.通过对强激光场作用下N2分子的研究,我们得到了在极端条件下同核双原子分子的动力学特点. 相似文献
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