排序方式： 共有41条查询结果，搜索用时 15 毫秒
21.
奥地利安东帕有限公司 《岩矿测试》2009,28(5):文后I
生物燃料来源于可再生的有机材料。绝大多数的生物质材料是植物产品或废物,如粮食、油料作物、木头、木板、树皮或碎屑。这些生物质材料由于可以作为替代能源而变得越来越重要,所以人们迫切需要一个能准确测定生物燃料中的主次量元素的分析方法。生物燃料中Al、K、Na、Ca、Mg、Fe和P等主要灰分形成元素,与生物质热工艺转化过程中的灰融、沉积形成和腐蚀等问题有关。而As、Cd、Co、Cu、Cr、Hg、Mo、Mn、Ni、Pb、V、Zn等次量元素由于大气排放问题也十分重要。虽然现在也有一些方法来分析固体燃料中的主量和次量元素;但是测量的精度仍不理想。其中的一个关键问题是这些生物质燃料中的灰分形成元素具有非常复杂 相似文献
22.
Future aquatic nutrient limitations 总被引：8，自引：0，他引：8
Nutrient limitation of phytoplankton growth in aquatic systems is moving towards a higher incidence of P and Si limitation as a result of increased nitrogen loading, a N:P fertilizer use of 26:1 (molar basis), population growth, and relatively stable silicate loading. This result will likely alter phytoplankton community composition, and may compromise diatom-->zooplankton-->fish food webs. 相似文献
23.
本文描述了一种关系，它使我们能够确定某一张像片上一个三维目标影像是否与另一张像片上一个目标的影像相匹配。这种影像匹配算法要求在两张像片上有９个同名像点的量测值，它仅依赖于像点坐标，而无需知道物方空间坐标或两摄影机的内外方位元素。该关系可以用于变化检测或分类，而且，当两张像片的透视中心存在较大差异时，这种方法特别有用。该研究的副产品是“核线方程”，它在影像的自动搜索和相关算法中很有用处。 相似文献
24.
奥地利安东帕有限公司 《岩矿测试》2007,26(5):文后II-文后II
Ni、V、Al、Si是石油的天然组分。其中M和V来源于形成石油的原始物质，它们易形成大而复杂的分子，从而使沸点非常高。含Ni和V的化合物在提炼过程中无法蒸馏，不能很经济地从燃料中去除。 相似文献
25.
The development of oil and gas recovery offshore of the Mississippi River delta began in shallow water in the 1950s, expanded into deeper waters, and peaked in the 1990s. This area of the outer continental shelf (OCS) is the historical and present location of >90% of all US OCS oil and gas production and reserves. The juxtaposition of its 4000 producing platforms, recovering $10 billion yr(-1) of oil, gas and produced water in the same area where about 28% of the US fisheries catch (by weight) is made and near 40% of the US coastal wetlands, makes this an area worth monitoring for regional pollutant loading. This loading may come from several sources, including sources related to OCS development, but also from the Mississippi River watershed. In this context, any contaminant loading on this shelf may be neither detectable nor significant against a background of climatic or biological variability. We examined the sedimentary record for indicators of industrial byproducts from OCS oil and gas development and of industrial products entering via the Mississippi River, primarily using vanadium (V) and barium (Ba) concentrations normalized for aluminum (Al). Barium is primarily used in drilling muds in the form of barite, whereas V is an important strengthening component of metal alloys, including steel. The fluctuations in the accumulation of Ba, but not V, were coincidental with the presumed use of barite. The fluctuations in V concentration in the sediments were coincidental with the national consumption of V. Copper (Cu), cadmium (Cd) and zinc (Zn) concentrations in sediments fluctuate coincidentally with V, not Ba, thus indicating that the dominant source of these trace metals in offshore sediments were derived from riverine sources, and were not primarily from in situ industrial processes releasing them on the shelf. This is not to suggest that local site-specific contamination is not a significant management or health concern. The low oxygen (hypoxia; < or = 2 mg l(-1)) zone that consistently covers much of this continental shelf's bottom layer in summer is attributed to nitrate loading from the Mississippi River. Increased nitrogen loading from river to shelf stimulates diatom production whose loading to the bottom layer and subsequent metabolism results in oxygen being depleted faster than it is replaced. In the last two decades there has been an increased accumulation of organic matter in sediments near the mouth of the Mississippi River. This coupling between river water, surface water and bottom water has recently expanded westward of the Atchafalaya River delta towards the Texas coast. The accumulation of biogenic silica (BSi) and carbon in dated sediments is coincidental with variations in riverine nitrate flux, but not with either V or Ba accumulation rates. These analyses indicate that both OCS development and riverine sources exert strong influences on the sediment constituents offshore, and that these influences may be independent of one another. 相似文献
26.
奥地利安东帕有限公司 《岩矿测试》2008,27(3):文后I-文后I
分析油类样品中的痕量元素有多种方法,例如采用有机溶剂稀释后用光谱法直接测定,在稳定乳液系统中测定,以及氧弹燃烧等常规消解方法;但是这些方法都存在一些固有问题。为了避免基质干扰问题,湿法消解方法是准确分析油类样品中痕量元素的理想的样品制备方法。目前已经有一个ASTM标准方法(ASTM C 1234—98),即利用HPA-S消解仪的高压、高温、密闭容器和洁净材质的优点,消解各种油类样品。该标准方法规定了可以用等离子 相似文献
27.
The goal of the present study was to examine the specific bioaccumulation of 22 trace elements in muscle, exoskeleton and hepatopancreas of black tiger shrimp Penaeus monodon from the Mekong River Delta (MRD), and the South Key Economic Zone (SKEZ), South Vietnam. The general tendency in most trace element concentrations among different tissues were hepatopancreas>exoskeleton>muscle. Comparisons of trace element levels in tissues between the two regions showed that concentrations of Se in muscle and As in all three tissues were higher in SKEZ; whereas in MRD, the higher concentrations of most elements such as Mn, Cu, Cd, Ba, Hg, were observed in tissues. These geographical variations in trace element levels may reflect the differences in human activities between the two regions of South Vietnam. The target hazard quotient (THQ) values for trace elements (<1) indicate that local residents are not exposed to potential health risks via the consumption of shrimp. 相似文献
28.
奥地利安东帕有限公司上海代表处 《岩矿测试》2009,28(1):文后II
即使在低浓度(μg/g)的情况下,硼会对钢的多种物理性能如硬度、可模锻性、可焊接性和淬透性都有不利影响。含2%(质量分数)硼的钢被核电厂用来存储和运输燃料棒,富含10B的钢具有吸收热中子的性能从而提供充分的辐射屏蔽。因此,对硼含量进行高精度和高准确的分析对于保证特种材料经济而可靠的生产具有十分重要的意义。1仪器样品的消解采用奥地利安东帕公司(Anton Paar GmbH)的Multiwave 3000微波消解仪,配16MF100转子[100 mLPTFE-TFM反应罐,程序压力2.0 MPa(20 bar)],带p/T传感器。元素分析是在PerkinElmer公司的Optima 3300 D 相似文献
29.
奥地利安东帕有限公司 《岩矿测试》2009,28(6):602-602
多环芳烃(PAHs)普遍存在于人为因素及自然因素产生的环境污染物中。PAHs具有化学结构稳定、较好的疏水性及容易在生物体内积累等特点,一旦形成就很难降解;部分结构的PAHs(如苯并[a]芘)具有致癌特性,所以PAHs一直是分析化学界的研究重点。建立一种精确的、高回收率并且低不确定度的测定环境样品中PAHs的方法,显得尤为重要。1仪器样品萃取是在奥地利安东帕公司(Anton Paar GmbH)的Multiwave 3000 SOLV微波萃取仪上进行,16MF100中压萃取转子。萃取液用安捷伦6890GC-5973MS进行检测,选用SIM模式,并用同位素内标法进行标定。2样品和萃取程序参考沉淀物 相似文献
30.
Produced water is a high salinity by-product resulting from oil and gas production. Disposal methods include surface water discharge. The current field method used to determine its fate in estuarine systems involves extending a compass oriented transect (COT) from the point source discharge--a method designed for a uniformly dispersing effluent discharged into a uniform offshore environment that may be inappropriate for the hydrologic and geomorphologic complexities found in estuarine systems. Prior research established the viability of the salinity stratification transect (SST) method. Both COT and SST methods were used in a small open bay to determine which more accurately detected effluent dispersion. Determination was based on sediment contaminant indicators (SCIs), including interstitial salinity, hydrocarbons, metals, and radium concentrations. Additionally, SCIs were evaluated for their ability to serve as indicators of effluent dispersion. The data revealed that SST stations exhibited higher contaminant concentrations and that this approach was more accurate in tracking the produced water plume. The data also suggested that SCIs varied in their ability to serve as indicators. Good indicators included interstitial salinity, total targeted aromatic hydrocarbons substantiated with a modified fossil fuel pollution index value, certain metals, and radium-228. 相似文献