广州地区蔬菜生产基地有机污染物含量状况及分布     

游远航 《吉林大学学报(地球科学版)》2015,45(4):1205-1216

为了解广州地区蔬菜基地有机污染物的分布情况,选取了6个代表性基地进行调查采样,测试分析了表层土壤、蔬菜及灌溉水中15种邻苯二甲酸酯(PAEs)化合物、16种多环芳烃(PAHs)化合物和19种有机氯农药(OCPs)化合物的质量分数及质量浓度.结果表明:在15种PAEs化合物的总质量分数(w(ΣPAEs))中,土壤样品为158.0~4 321.0 ng/g,蔬菜样品为1 134.0~48 576.0 ng/g;水样中15种PAEs化合物的总质量浓度(ρ(ΣPAEs))为632.0~14 271.0 ng/L;就单个化合物而言,以DiBP、DBP、DEHP三种污染物为主,其三项之和占所有PAEs质量分数的97.5%~99.1%;在16种PAHs化合物的总质量分数(w(ΣPAHs))中,土壤样品为28.48~1 121.96 ng/g,蔬菜样品为238.09~1 000.61 ng/g;水样中16种PAHs化合物的总质量浓度(ρ(ΣPAHs))为338.21~1 239.78 ng/L;在19种OCPs化合物的总质量分数(w(ΣOCPs))中,土壤为0.04~71.28 ng/g,蔬菜为1.08~9.18 ng/g.总体上看,各基地土壤中DBP质量分数均超标,多环芳烃类在灵山、花东、黄埔菜地土壤中存在轻微污染,有机氯农药均未出现污染.  相似文献   

Chemical,isotopic and amino acid composition of Mukundpura CM2.0(CM1) chondrite: Evidence of parent body aqueous alteration     

N.G.Rudraswami  A.K.Naik  R.P.Tripathi  N.BhANDari  S.G.Karapurkar  M.Shyam Prasad  E.V.S.S.K.Babu  U.V.R.Vijaya Sarathi 《地学前缘(英文版)》2019,10(2):495-504

The carbonaceous chondrites are intriguing and unique in the sense that they are the only rocks that provide pristine records of the early solar nebular processes. We report here results of a detailed mineralogical, chemical, amino acid and isotopic studies of a recently observed fall at Mukundpura, near Jaipur in Rajasthan, India. Abundance of olivines in this meteorite is low and of serpentine minerals is high. FeO/SiO_2 = 1.05 in its Poorly Characterized Phases(PCP) is similar to that observed in other CM2.0 chondrites. The water content of ～9.8 wt.% is similar to that found in many other CM chondrites.Microscopic examination of matrix shows that its terrestrial weathering grade is WO but aqueous parent body alteration is high, as reflected in low abundance of identifiable chondrules and abundant remnants of chondrules(～7%). Thus, most of the chondrules formed initially have been significantly altered or dissolved by aqueous alterations on their parent bodies. The measured bulk carbon(2.3%) and nitrogen content and their isotopic(δ¹³C =-5.5‰, δ¹⁵N = 23.6%0) composition is consistent with CM2.0 classification probably bordering CM1. Several amino acids such as Alanine, Serine, Proline, Valine, Threonine,Leucine, Isoleucine, Asparagine and Histamine are present. Tyrosine and Tryptophan may occur in trace amounts which could not be precisely determined. All these data show that Mukundpura chondrite lies at the boundary of CM2.0 and CM1 type carbonaceous chondrites making it one of the most primitive chondrites.  相似文献   

免疫多糖对栉孔扇贝酸性磷酸酶、碱性磷酸酶和超氧化物歧化酶活性的影响   总被引：23，自引：1，他引：23  

牟海津  江晓路  刘树青  管华诗 《中国海洋大学学报(自然科学版)》1999,(3)

在栉孔扇贝的血清、血细胞和肝脏提取液中均发现有酸性磷酸酶（ＡＣＰ）、碱性磷酸酶（ＡＬＰ）和超氧化物歧化酶（ＳＯＤ）活性,其中,ＡＣＰ和ＡＬＰ在肝脏中的活性最高。采用１．０％的虫草多糖或海藻多糖作为免疫药物,对栉孔扇贝进行注射刺激后,发现血清中的ＡＣＰ、ＡＬＰ和ＳＯＤ活性有显著提高,血细胞中的ＡＣＰ和ＳＯＤ活性也有所增加,而肝脏提取液的这三种酶活性的变化不很明显。研究认为这两种多糖具有增强栉孔扇贝免疫活性的作用,在水产养殖业中有一定的开发价值。  相似文献   

The Monitor project: rotation of low-mass stars in the open cluster NGC 2547     

Jonathan Irwin  Simon Hodgkin  Suzanne Aigrain  Jerome Bouvier  Leslie Hebb  Estelle Moraux 《Monthly notices of the Royal Astronomical Society》2008,383(4):1588-1602

We report on the results of an I -band time-series photometric survey of NGC 2547 using the MPG/ESO 2.2-m telescope with Wide Field Imager, achieving better than 1 per cent photometric precision per data point over  14 ≲ I ≲ 18  . Candidate cluster members were selected from a V versus V − I colour–magnitude diagram over  12.5 < V < 24  (covering masses from  0.9 M_⊙  down to below the brown dwarf limit), finding 800 candidates, of which we expect ∼330 to be real cluster members, taking into account contamination from the field (which is most severe at the extremes of our mass range). Searching for periodic variations in these gave 176 detections over the mass range  0.1 ≲ M /M_⊙≲ 0.9  . The rotation period distributions were found to show a clear mass-dependent morphology, qualitatively intermediate between the distributions obtained from similar surveys in NGC 2362 and 2516, as would be expected from the age of this cluster. Models of the rotational evolution were investigated, finding that the evolution from NGC 2362 to 2547 was qualitatively reproduced (given the uncertainty in the age of NGC 2547) by solid body and core-envelope decoupled models from our earlier NGC 2516 study without need for significant modification.  相似文献   

A populous intermediate-age open cluster and evidence of an embedded cluster among the FSR globular cluster candidates     

E. Bica  C. Bonatto 《Monthly notices of the Royal Astronomical Society》2008,384(4):1733-1740

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Discovery of an open cluster with a possible physical association with a planetary nebula     

C. Bonatto  E. Bica  J. F. C. Santos Jr 《Monthly notices of the Royal Astronomical Society》2008,386(1):324-336

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The old metal-poor open cluster ESO 92-SC05: accreted from a dwarf galaxy?     

S. Ortolani †  E. Bica  B. Barbuy 《Monthly notices of the Royal Astronomical Society》2008,388(2):723-728

The study of old open clusters outside the solar circle can bring constraints on formation scenarios of the outer disc. In particular, accretion of dwarf galaxies has been proposed as a likely mechanism in the area. We use BVI photometry for determining fundamental parameters of the faint open cluster ESO 92-SC05. Colour–magnitude diagrams are compared with Padova isochrones, in order to derive age, reddening and distance. We derive a reddening   E ( B − V ) = 0.17  , and an old age of ∼6.0 Gyr. It is one of the rare open clusters known to be older than 5 Gyr. A metallicity of   Z ∼ 0.004  or  [M/H]∼−0.7  is found. The rather low metallicity suggests that this cluster might be the result of an accretion episode of a dwarf galaxy.  相似文献   

A Reinvestigation of the Physical Properties of Pismis 3 based on 2MASS Photometry     

Tadross A. L. 《中国天文和天体物理学报》2008,8(3):362-368

As a continuation of a series of work, we aim to refine and re-determine the physical parameters of previously rarely or un-studied open star clusters with good quality CMDs using Near-IR JHK photometry. Here we present a morphological analysis of the 2MASS database (the digital "Two Micron All Sky Survey") for the open cluster Pismis 3. Some of the physical parameters are estimated for the first time, and some others, re-determined.  相似文献   

煤矿酸性矿井水主动式生物修复中铁的行为与归宿     

盛益之  王广才  刘莹  李广贺 《地学前缘》2018,25(4):299-306

酸性条件下Fe(II)的生物氧化过程可以被有效应用于煤矿酸性矿井水修复中,但是Fe行为与归宿的不确定性增加了应用难度。本研究通过对某煤矿酸性矿井水场地发生的生物地球化学过程进行监测,富集培养场地沉积物嗜酸微生物群落,进行室内恒化生物反应器连续流实验,探究微生物作用下Fe及其他金属离子的行为与归宿。研究表明,Fe的形态转化是场地和反应器中最主要的生物地球化学过程。当pH<2.7时,反应更倾向于产生溶解性Fe(III);当2.7相似文献   

Comment on: Mass Fractions of Forty‐Six Major and Trace Elements,Including Rare Earth Elements,in Sediment and Soil Reference Materials Used in Environmental Studies. Fiket et al. (2017), Geostandards and Geoanalytical Research, 41, 123–135     

Vibor Roje 《Geostandards and Geoanalytical Research》2019,43(2):317-327

This paper is intended to be a constructive discussion of Fiket et al. (2017, Geostandards and Geoanalytical Research , 41 , 123–135), who dealt with the determination of major, trace and rare earth elements in several sediment and soil certified reference materials. In the present author's view, the paper by Fiket et al. (2017) suffers from a lack of reference to several publications in which somewhat similar results had already been reported. The present contribution therefore provides a comparison of previously published results with those of Fiket et al. for the CRMs soil NCS DC 77302 (GBW 07410), stream sediment NCS DC 73309 (GBW 07311), marine sediments MESS‐3 and NCS DC 75301 (GBW 07314) and estuarine sediment IAEA‐405. It is argued that this fuller consideration (a) allows critical evaluation of the quality of the results presented by Fiket et al. and (b) highlights the advantages of their work. Finally, attention is drawn to the (possible or real) problems that can arise during simultaneous determination of multiple trace elements.  相似文献