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介绍了固体氧化物燃料电池(SOFC)的工作原理,从四大守恒定律出发,建立了管式SOFC的数学模型,以H2 ,CO,CH4 ,C2 H2 ,C2 H4 ,C2 H6 这6种可燃气体为研究对象,给出了可燃气体的含量与SOFC输出电压峰面积的函数曲线图。结果表明函数曲线是单调的,在一定范围内呈现出近似于线性的特征。将SOFC结合现代色谱技术,成功研制出变压器油中溶解气体分析(DGA)在线监测仪。现场投运结果表明该技术可以满足电力变压器DGA在线监测与故障诊断的要求,具有线性度好、灵敏度高、方便、清洁和自动化程度高等优点。 相似文献
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简要介绍了小浪底水电厂开展变压器油色谱在线监测的意义,以及采用动态顶空平衡法进行油气分离、采用光声光谱技术进行气体检测的TransFix变压器油中溶解气体及微水在线监测系统的原理及应用情况,给出了相关的试验数据. 相似文献
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某富营养化池塘夏季温室气体通量的昼夜变化 总被引:1,自引:0,他引:1
为揭示富营养化浅水池塘昼夜性的温室气体通量特征,利用DLT-100温室气体分析仪高采样频率的优势,通过48 h的在线观测,获得了宜昌野猪林池塘夏季CH4和CO2扩散和冒泡释放的昼夜性通量数据。观测点F点水气界面总CH4和CO2通量分别约为595.2,1 450.8 mg/(m2·d),CH4和CO2气泡排放量分别占到总排放量的99.7%和3.0%。观测期内冒泡存在高度时间变异性,最大的一次CH4冒泡释放速率为424.28 mg/(m2·h),占2 d内总气泡释放量的35.75%,而大多数时段的CH4冒泡速率低于20.0 mg/(m2·h)。监测期内CH4和CO2扩散通量的最高值分别为各自最低值的6.0和6.5倍。监测表明,富营养化浅水池塘夏季CH4通量非常高,且主要以冒泡方式释放;而CO2通量明显响应于浮游植物光合作用和呼吸作用交替的新陈代谢作用,存在昼夜性的变化规律。 相似文献
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介绍了北京SERVERON公司产品TM8油气在线监测装置及其在三峡水力发电厂4号主变压器上的应用状况,展示了利用在线溶解气体数据对变压器设备维护的辅助决策作用,并对今以后组建全厂油气在线监测系统提出了总体规划方案和新的用户需求。 相似文献
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为探索小型水域温室气体的排放规律,采用温室气体快速分析仪-密闭式静态通量箱法对湖北宜昌市三峡大学求索溪冬季水-气界面温室气体通量(CH4和CO2)进行了24 h连续观测。观测结果显示,CH4和CO2的变化呈正相关,CH4和CO2全天均处于释放状态;CO2通量与气压、水温呈正相关,与气温、p H值、溶解氧、叶绿素a呈负相关;CH4仅与气压呈正相关而与其他环境因子均呈现负相关;CH4和CO2在10:00和21:00左右同时接近全天的平均值,该时段可作为单次采样时间参考。 相似文献
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变压器局部放电常用检测方法包括脉冲电流法、油中溶解气体分析(DGA)法、超声波法、无线电干扰电压(RIV)法、光测法、射频检测法及化学方法等。在上述方法分析的基础上,根据电晕放电的紫外光特性提出了用紫外脉冲检测变压器内部放电的新方法。分析了变压器电晕放电与紫外光特性的关系、紫外光在变压器内部的传播特性,论证了电晕放电的紫外脉冲法检测原理,提出了变压器内部电晕放电故障定位方法,设计了紫外脉冲监测方法并进行了实验验证。结果表明,紫外脉冲法可用于变压器电晕放电的在线监测。 相似文献
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介绍了几起变压器油中溶解气体含量异常案例的分析过程,阐述了如何正确利用油中溶解气体含量分析进行变压器的故障诊断,避免发生误判断。 相似文献
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油中溶解气体分析是目前发现变压器潜伏性故障的重要方法,鉴于用IEC推荐的三比值法中编码缺陷(编码超出码表)及变压器故障诊断的复杂性,文中详细阐述了如何将灰关联熵应用于变压器故障诊断。首先通过统计方法,选择典型油中气体作为参考列,并经反复调整,挖掘出油中气体所含故障信息,然后利用灰关联熵方法进行变压器故障类型诊断。该方法基于融合互补的思想,将灰关联分析方法与信息熵理论有机结合起来,克服了单一灰关联分析中易造成局部关联及信息损失等缺陷,尽可能多地包含变压器本体所含信息。实例分析结果表明,该方法具有较好的分类效果。 相似文献
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根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
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The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 相似文献
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In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed
in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash
and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers
of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional
components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect
dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system,
configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants
of dry ash utilization and the advantages of producing of size-separated particles are considered.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed. 相似文献