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31.
Investigation of anthropic effects connected with metal ions concentration, organic matter and grain size in Bormida river sediments 总被引:9,自引:0,他引:9
Emilio Marengo Maria Carla Gennaro Elisa Robotti Piero Rossanigo Caterina Rinaudo Manuela Roz-Gastaldi 《Analytica chimica acta》2006,560(1-2):172-183
An investigation on the sediment composition and grain size was carried out along the Bormida river (Piedmont, Northern Italy). The samples were taken both in the riverbed and on its banks. Multivariate statistical exploratory methods permitted to identify possible sources of primary pollution. In particular, principal component analysis (PCA) showed that there are probably at least three anthropogenic main causes of pollution, one connected with Cr, Ni and Sn, the second with cadmium and the last one with mercury. Some correlations were found between heavy metal ion concentrations and organic matter and/or the sediment grain size. Differences between the samples collected in the riverbed and on the banks were identified and the relationships between the principal components and the distance of the samples from the riverbed and from the hot spot represented by the ACNA industrial site were also analyzed. 相似文献
32.
Bjrn kermark 《中国化学快报》2005,16(1):89-92
Two novel high valent complexes [M2(III, III)L(p--OAc)2].PF6 (M=Mn, Fe; 9) were prepared, where L was the tri-anion of 2,6-bis{[(2-hydroxy-3-(morpholin-4-yl methyl)-5-tertbutyl benzyl)(pyridyl-2-methyl)amino]methyl}-4-methyl phenol which contained additional phenolic, tert-butyl and morpholin-4-yl methyl groups compared to its parent [Mn2(Ⅱ, Ⅱ)(bpmp)(μ-OAc)2]-ClO4 (10). These improvements decreased the difference between the new model and (Mn)4 cluster (OEC in nature). 相似文献
33.
基于支持向量机的羰基化合物红外光谱研究 总被引:1,自引:0,他引:1
设计了一个4层分等级分类系统,通过支持向量机技术对羰基化合物的红外光谱成功地进行了信息分类和提取,并与人工神经网络进行比较,结果表明:支持向量机对羰基类化合物红外光谱分类效果优于人工神经网络;另外详细探讨了表征酰胺类化合物的特征光谱峰片段对识圳伯仲叔酰胺的影响,证明了酰胺的N-H伸缩振动峰对识别伯仲叔酰胺贡献最大,为构建红外光谱智能解析系统提供了定量依据。 相似文献
34.
本文对几种人工光合作用反应中心系统,做一个简单的综述,其中包括叶绿素和细菌叶绿素二聚体,卟啉二聚体,卟啉-苯醌共价键络合物以及其他合成中心。 相似文献
35.
Artificial red cells with crosslinked hemoglobin membranes 总被引:1,自引:0,他引:1
Thomas A. Davis William J. Asher Herbert W. Wallace 《Applied biochemistry and biotechnology》1984,10(1-3):123-132
Artificial cells containing concentrated hemoglobin (Hb) solution were prepared by interfacial polymerization of Hb with glutaraldehyde
(GA) in liquid membrane capsules (LMC). A solution containing 30% of Hb was emulsified in mineral oil as red cell-size microdroplets,
and this emulsion was dispersed in an aqueous phase containing glutaraldehyde to form LMC. The LMC were semipermeable templates
that held the microdroplets of Hb in suspension while GA diffused through the oil to the microdroplet surfaces. The GA crosslinked
Hb at the surface of each microdroplet to form an artificial red-cell membrane encapsulating Hb solution. A water-soluble
surfactant was used to eject the cells from the LMC and suspend them in saline.
Several surfactants were evaluated. Cell size was controlled by agitation speed during preparation of the original emulsion.
Cells of 2.52 = ±1.69 μm were prepared. The encapsulated Hb retained capacity to bind and release O2. The cells had aP
50 of 8.9 torr (1200 Pa) and a capacity of 0.55 cc O2/g of total Hb, indicating that the crosslinked portion of the Hb did not contribute to O2 transport. 相似文献
36.
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38.
Miguel A. De La Rosa José A. Navarro Mercedes Roncel 《Applied biochemistry and biotechnology》1991,30(1):61-81
The production of chemicals and fuels, or energy-rich compounds, from water by sunlight is described as a particularly attractive
means for the conversion of solar energy to a valuable renewable resource. The redox properties of photoexcited molecules
and the operating mechanism of light-driven systems are first considered. The mechanism of water oxidation carried out by
higher plants and green algae-which is actually one of the most important biochemical reactions—as well as that of artificial
photosystems, up-to-now designed trying to simulate the natural process with higher efficiency and simplicity, are likewise
discussed. A number of biological and chemical light-driven systems are presented as practical ways to solar energy conversion. 相似文献
39.
Heat capacities of concentrated multicomponent aqueous electrolyte solutions at various temperatures
Boris S. Krumgalz Ilan A. Malester Irving J. Ostrich Frank J. Millero 《Journal of solution chemistry》1992,21(7):635-649
The specific heat capacities of the aqueous multicomponent system NaCl +KCl+MgCl2+CaCl2 with ionic strength between 8.3 and 9.6 (resembling Dead Sea waters) were measured between 15°C and 45°C. The obtained data were fitted to an empirical equation as a function of concentration and temperature. The thermodynamic functions of the studied multicomponent system were found to be strongly influenced by changes in MgCl2 concentrations. The application of Young's rule to such concentrated systems was checked at 25°C. The calculated (by Young's rule) specific heat capacitiesC
p and apparent molar heat capacities Cp, of these multicomponent electrolyte solutions were in reasonable agreement with the measured values (–0.008 J-g–1-K–1 and –2.6 J-mol–1-K–1, respectively). 相似文献
40.
Gonzalo Astray Juan F. Gálvez Juan C. Mejuto Oscar A. Moldes Iago Montoya 《Journal of computational chemistry》2013,34(5):355-359
In this article, an artificial neural network to predict the flash point of 95 esters was implemented. Four variables were used for its development. A neural network with 4‐5‐8‐5‐1 topology was encountered to gain the best agreement of the experimental results with those predicted (square correlation coefficient (R2) and root mean square error were 0.99 and 5.46 K for the training phase and 0.96 and 13.02 K for the testing set). © 2012 Wiley Periodicals, Inc. 相似文献