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Intrusion of quartz‐monzodioritic igneous bodies of Oligocene age into Eocene lithic crystal tuffs and trachy‐basalts resulted in the occurrence of a widespread argillic alteration zone in the Jizvan district (northern Iran). Mineralogically, the argillic alteration zone includes minerals such as kaolinite, quartz, smectite, pyrophyllite, muscovite‐illite, alunite, rutile, calcite, feldspar, chlorite, hematite and goethite. Therefore, the non‐CHARAC behaviour for trace elements in the argillic samples is reflected in the non‐chondritic Y/Ho and Zr/Hf ratios and the irregular REE patterns, which appear related to the tetrad effect phenomenon. The chondrite‐normalized REE distribution patterns indicate both concave (W‐shaped) and convex (M‐shaped) tetrad effects in the argillic samples. Based on the field evidence and the results from geochemical studies, it can be concluded that the samples from the argillic alteration zone having high fourth tetrad effect values (>0.30) were developed in the fault and breccia zones. The results indicate that factors such as preferential scavenging by Mn‐oxides, crystallization of clay minerals, fluid‐rock interaction, overprint of hypogene mineral assemblage by supergene ones, and the structural control, have all played an important role in the occurrence of tetrad effects in samples of the argillic zone in the Jizvan district. 相似文献
44.
In this work, the treatment of photographic processing wastewaters (PPW) by electro‐Fenton process has been investigated. The Influence of operating conditions on kinetics and efficiency of electro‐Fenton process has been evaluated using carbon felt cathode and platinium (Pt) or boron‐doped diamond (BDD) anode. The results of electro‐Fenton treatment of PPW have shown that nearly complete removal of total phenols was obtained for all combinations with pseudo‐first rate constants of 0.07, 0.012, and 0.018/min for carbon felt/Pt, carbon felt/BDD and Pt/BDD cathode/anode combinations, respectively. The combination of carbon felt cathode with BDD anode achieved the highest total organic carbon (TOC) removal of 90%, while it did not exeed 40% for carbon felt/Pt combination. Increasing current intensity and Fe2+ dose enhances the efficiency of electro‐Fenton process. However, increasing pH decreases TOC removal during the treatment of PPW by electro‐Fenton process. The highest efficiency of electro‐Fenton process using BDD anode can be explained by the contribution of direct and indirect oxidation routes in the degradation mechanism of organics including (i) oxidation via hydroxyl radicals generated from the catalytic decomposition of H2O2 and from water discharge on BDD anode, (ii) direct oxidation of certain organic compounds on BDD anode, and (iii) mediated oxidation with inorganic oxidants electrogenerated from anodic oxidation of supporting salts. 相似文献
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A. M. Ferrero G. Forlani R. Roncella H. I. Voyat 《Rock Mechanics and Rock Engineering》2009,42(4):631-665
The location and orientation of rock discontinuities, which are traditionally obtained from geological surveys with obvious
drawbacks (safety, rock face accessibility, etc.), may also be derived from a detailed and accurate photogrammetric or laser
scanning survey. Selecting from the point cloud determined on the rock face a set of points distributed on a particular discontinuity,
location, dip, and dip direction can be computed from the least-squares estimate of the plane interpolating the set of points.
Likewise, the normal vector to the surface may be computed from an interpolation or approximation of the surface by appropriate
functions. To become a real alternative (both in terms of productivity as well as accuracy) to a traditional survey, interactive
or automated software tools are necessary, to allow the efficient selection of the point sets on the discontinuities or the
interpretation of the normal vector pattern. After introducing the two best technologies available today for data acquisition
and their performance, the paper presents an approach, based on the random sample consensus (RANSAC) procedure, to the segmentation
of the point cloud into subsets, each made of points measured on a discontinuity plane of the rock face. For each subset,
the plane’s equations coefficients are first determined by robust estimation and then refined by least-squares estimation
after outlier removal. The segmentation algorithm has been implemented in RockScan, a software tool developed to facilitate
the interaction with the point cloud in the identification of the discontinuities; rather than using the three-dimensional
(3D) data, selection of regions of interest is performed on oriented images of the rock face. Finally, application of RockScan
to four different test sites is discussed and results presented. The sites differ in size (from tens to hundreds of meters),
rock surface characteristics, and the technology used to produce the point cloud (in three cases photogrammetry, in the fourth
laser scanning), giving the opportunity to test the methodology in different contexts. In the first and in the fourth site
an extensive traditional survey has been performed, providing reference data to validate the RockScan results. 相似文献
48.
Hiroshi Kawamura 《Journal of Oceanography》1998,54(5):383-399
The Ocean Color and Temperature Scanner (OCTS) on board the Advanced Earth Observing Satellite (ADEOS) observed the chlorophyll-a concentration in the surface layer and sea surface temperature in global oceans from October 1996 to June 1997. The OCTS
team was formed in the National Space Development Agency of Japan (NASDA) Earth Observation Research Center (EORC) to develop
algorithm, calibrate and validate OCTS products and promote OCTS data usage. Intensive efforts to improve the quality of the
OCTS products were made after the launch of ADEOS. Much sea-truth data was collected, and the algorithms to retrieve the ocean
parameters have been revised several times. The OCTS data were distributed to the user community through the Internet while
OCTS was functioning. An overview of the OCTS mission is presented in this paper.
The OCTS Team is formed by NASDA personnel and supporting scientists listed in Appendix 1. 相似文献
49.
Hydroxyl radicals, generated radiolytically in N2O/O2‐saturated solutions, yield in their reaction with atrazine equal amounts of deethylatrazine and acetaldehyde (40% of OH radical yield) and deisopropylatrazine and acetone (16%), respectively. The precursors of deethylatrazine and acetaldehyde is their Schiff base which hydrolyzes slowly (OH–‐catalyzed: k = 5.2 dm3 mol–1 s–1). The hydrolysis of the Schiff base of deisopropylatrazine and acetone is too fast to be detected. In a pulse radiolysis experiment, the intermediate formed upon OH‐radical attack (k = 3·109 dm3 mol–1 s–1) has a strong absorption at 440 nm. It decays in the presence of oxygen (k = 1.3·109 dm3 mol–1 s–1), and upon deprotonation [pKa(peroxyl radicals) ≈ 10.5] the peroxyl radicals thus‐formed eliminate superoxide radicals (k = 2.9·105 s–1). s‐Triazine itself reacts much more slowly with OH radicals (k = 9.7·107 dm3 mol–1 s–1). This can explain, why in the case of atrazine in comparison to other aromatic compounds, e.g. toluene, the addition of the OH radical to the ring (estimated at ca. 40%) is of relatively little importance as compared to an H‐abstraction from (activated) positions of the side groups. 相似文献
50.
Simulation of the asian monsoon by IAP AGCM coupled with an advanced land surface model (IAP94) 总被引：3，自引：0，他引：3
ＳｉｍｕｌａｔｉｏｎｏｆｔｈｅＡｓｉａｎＭｏｎｓｏｏｎｂｙＩＡＰＡＧＣＭＣｏｕｐｌｅｄｗｉｔｈａｎＡｄｖａｎｃｅｄＬａｎｄＳｕｒｆａｃｅＭｏｄｅｌ（ＩＡＰ９４）ＺｅｎｇＱｉｎｇｃｕｎ（曾庆存）,ＤａｉＹｏｎｇｊｉｕ（戴永久）ａｎｄＸｕｅＦｅｎｇ（薛峰... 相似文献