977 resultados para Termoluminescência (TL)
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Thirty-eight surficial deposit samples were collected from the equatorial North Pacific, and the natural thermoluminescence (TL) characteristics of both bulk and clay fraction samples ( < 2 mu m fractions) were studied by the FJ427 - Al automatic TL Dosimeter for the first time. With the measurements of clay mineral composition, element composition by XRD and ICP, the correlations between TL intensity and sedimentary environment proxies were analyzed, such as water depth, ratio of FeO to Fe2O3 contents, LOI, and major clay mineral concentration, and it was found the bulk sample's TL signal was stronger than the clay ones. Usually, increase in the clay components may result in the decrease of TL intensity. From the shape of TL curves, the pelagic sediments can be divided into two groups: the majority group has two glow peaks, in general, the first peak is broad and flat, but the second narrow and sharp; the minority group only has a single peak because the first is absent. The peak centers of TL curves are almost fixed, falling in the temperature sections 230 similar to 260 and 390 similar to 405 degrees C respectively. Lorentz model packed in the Origin 7.5 was chosen to deal with the TL curves. From the processing results, three parameters ( H, C and A), corresponding to the height, center, and kurtosis of TL curve, were obtained to describe the curve characteristics. The correlations between TL curve parameters and sedimentary environment proxies were also calculated. On the basis of the above work, the relationship between TL characteristics and sediment type, mineral composition, sedimentary environment of surface sediments was discussed in the study area, and a conclusion is: sediments from the environment of shallower water, higher organic contents and weaker reductivity have stronger TL signals.
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本研究以中国对虾为材料,以杂交育种和选择育种为目标,进行了系统的中国对虾杂交育种试验、生长性状遗传参数试验及其分子遗传连锁图谱的构建工作。结果表明以不同地理群体杂交作为基础群体,然后采用系统的选择育种方法可以获得较好的选择效果。构建的遗传连锁图谱为中国对虾分子辅助育种提供一定的基础。这些试验结果为中国对虾合理系统的育种工作提供了理论基础和数据支持。其具体结果如下: 1. 试验对中国对虾黄渤海水域乳山湾群体(WYP)和朝鲜半岛南海群体(WKN)的2个群体及其杂交后代不同月龄生长情况和存活率进行了研究,测量体长(TL)、头胸甲长(CL)、头胸甲宽(CW)、第2、3腹节高(HST)、第2、3腹节宽(WST)、体重(BW)和存活率共7个性状,计算各项指标的杂种优势率,并对各性状进行了方差分析和多重比较。其3月龄生长情况和存活率研究结果表明,存活率在乳山湾群体(WYP♀)× 朝鲜半岛南海群体(WKN♂)杂交后代出现杂种劣势外,其他指标都表现出不同程度的杂种优势(4.37%~23.96% )。除了存活率外,杂交后代生长性状均显著高于亲本,乳山湾群体(WYP♀)×朝鲜半岛南海群体(WKN♂)杂交后代高于朝鲜半岛南海群体(WKN♀)× 乳山湾群体(WYP♂)杂交后代,黄渤海水域乳山湾群体高于朝鲜半岛南海群体后代。为确定测量性状与中国对虾体重的相关程度,建立了用体长(X1),头胸甲宽(X2),第2、3腹节宽(X3),头胸甲长(X4),第2、3腹节高(X5)估计体重的多元回归方程:Y = -2.056 + 0.03X1 + 0.076X2 + 0.078X3 + 0.033X4 + 0.043X5。 2. 中国对虾黄渤海水域乳山湾群体(WYP)和朝鲜半岛南海群体(WKN)2个群体及其杂交后代在4月龄时期的6个生长指标和存活率的杂种优势范围在0.514%到14.95%之间,WYP♀×WKN♂杂交后代在这7个指标中都高于WKN♀×WYP♂杂交后代。5月龄杂交后代也表现出一定程度的杂种优势,其范围在-9.000%~19.090%之间,但头胸甲长、第2、3腹节处高和存活率3个指标出现杂种劣势。不同杂交组合各个阶段生长发育情况和存活率在杂种优势表现出一定的规律。随着月龄的增加,WKN♀×WYP♂杂交后代杂种优势率有所增加,而WYP♀×WKN♂杂交后代的却有所降低。ANOVA分析结果表明,杂交后代在存活率方面与双亲差异不显著。4月龄的分析结果发现杂交后代在WST和BW这2个指标上存在显著差异。LSD多重比较结果显示,WYP♀×WKN♂杂交后代在BW指标上与亲本存在显著差异,在WST指标方面与其他3个组合的后代差异显著。5月龄的数据分析结果发现,杂交后代除体重存在显著差异外,其他各项指标差异均不显著。LSD多重比较结果发现,WKN♀×WYP♂杂交后代体重与其亲本WKN存在显著差异。 3. 对2个野生群体——朝鲜半岛南海岸群体(WKN)和黄渤海群体(WYP)和3个养殖群体——朝鲜半岛群体的养殖一代(FKN),黄海1号(HH1)和即抗98(JK98)进行杂交试验的研究,结果表明JK98 (♀) WKN (♂)组合在存活率方面最高,其余的依次为WYP (♀) WKN (♂),WKN (♀) WYP (♂),FKN (♀)HH1 (♂) 和 WYP (♀) FKN (♂)。而在体重方面FKN(♀) HH1(♂)组合最高,其余的依次为WKN (♀) WYP (♂),WYP (♀) WKN (♂),WYP (♀)FKN (♂) 和 JK98 (♀)WKN (♂)。在所有生长性状方面,JK98 (♀) WKN (♂)在5个组合中是最低的。方差检测结果表明,TL、CL、HST、LL和BW这5个指标在不同组合间存在差异,而其他指标不存在差异。多重比较结果发现JK98 (♀)WKN (♂)组合的TL与其他组合间差异极显著,HST指标与WKN (♀) WYP (♂),FKN(♀) HH1(♂)和 WYP (♀) WKN (♂)这3个组合差异显著,BW指标与WKN (♀) WYP (♂) 和 FKN(♀) HH1(♂)差异显著。 4. 通过人工授精的方法建立了中国对虾21个半同胞家系,测量了中国对虾21个半同胞(46个全同胞)家系的TL、CL、CW、HST、WST、第1腹节长(FL)、第6腹节长(LL)。利用MTDFREML软件得到生长性状遗传力在0.15~0.35之间,属于中度遗传力范围。TL的遗传力为0.34±0.071,CL的为0.30±0.070,CW为0.35±0.077,WST为0.33±0.073,HST为0.33±0.073,FL的最低为0.15±0.044,LL的为0.24±0.059。各个性状间表现出高的正相关,其中CW和TL以及HST的遗传相关最大,FL和WST的遗传相关最小。 通过以上杂交育种和选择育种的研究,认为单纯的依靠杂交育种来改善中国对虾的育种工作可能具有一定的局限性。所以在实际的育种过程中,以中国对虾不同群体的杂交后代作为基础群体,并以此为基础进行系统的选择育种应该具有更大的潜力。 5. 本试验利用中国对虾F2群体和AFLP分子标记技术进行了遗传连锁图谱的构建。利用55对AFLP引物组合对F2家系的110个个体进行了研究,结果检测到532个符合作图策略的AFLP标记。利用卡方检验检测分离位点是否符合孟德尔分离定律。对于符合3:1比例的分离位点利用F2自交模型构建性别平均连锁图谱,对于符合1:1比例的分离位点利用拟测交理论分别构建中国对虾的雌性和雄性遗传连锁图谱。雌性、雄性和性别平均遗传图谱分别有28、35和44个连锁群,图谱实际长度分别为1090、1617和1772.1 cM。中国对虾遗传连锁图谱估计基因组长度为2420 cM,符合与人类基因组相比的对虾类基因组长度。中国对虾雄性遗传连锁图谱比雌性遗传连锁图谱长32.6%,这可能说明中国对虾不同性别存在不同的重组率。通过皮尔逊相关系数检测认为AFLP标记在中国对虾图谱上分布均匀。本文利用AFLP标记构建的中国对虾遗传连锁图谱为中国对虾基因组研究和遗传改良提供一定的基础,同时也应该开发微卫星等共显性标记,为遗传连锁图谱的整合提供条件。
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Organochlorine contaminants including 12 polychlorinated biphenyl (PCB) congeners and 18 insecticides were determined in water, pore water and sediments of the Jiulong River Estuary and Western Xiamen Sea, China. The results showed that the levels of the total PCBs ranged from non-detectable to 1500 ngl(-1) in water, from 209 to 3870 ngl(-1) in pore water, and from 2.78 to 14.8 ng g(-1) dry weight in sediments. Total organochlorine insecticide concentrations were from below the limit of detection to 2480 ngl(-1) in water, from 267 to 33400 ngl(-1) in pore water, and from 4.22 to 46.3 ng g(-1) dry weight in sediments. Concentrations of PCBs and insecticides in pore water were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. The PCB congeners with the highest concentrations were CB153, CB180 and CB194, which together accounted for 68-87% of total PCBs in water, pore water and sediment. Among the hexachlorocyclohexane (HCH) compounds, beta-HCH was found to be a major isomer. Analysis of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane (DDT) and its metabolites showed that 1, 1-dichloro-2[o-chlorophenyl]-2[p-chlorophenyl]-ethylene (DDE) was dominant in the group. In comparison to a 1998 study in the Western Xiamen Sea, levels of organochlorines were enhanced due probably to recent inputs and changes in sediments. (c) 2004 Elsevier Ltd. All rights reserved.
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The relationship between Alexandrium tamarense (Lebour) Balech, one of red-tide alga, and two strains of marine bacteria, Bacillius megaterium(S-7) and B. halmapulus(S-10) isolated from Xiamen Western Sea, was investigated by evaluating the growth state of A. tamarense and the variation of P-glucosidase activity in co-culture system. The results showed the growth and multiplication of the alga were related with the concentration, genus speciality of the bacteria, and growth stage of the alga itself. The growth of A. tamarense was obviously inhibited by S7 and S, at high concentration. Either inhibition or promotion contributed much more clearly in earlier than in later stage of the growth of the alga. Furthermore, there was a roughly similar variation trend of the activity of extra-cellular enzyme, beta-glucosidase, in the water of the separately co-cultured bacteria S-7 and S-10 with the alga. The beta-glucosidase activity (beta-GlcA) rapidly increased during the later algal growth accompanying the increase of the lysis of the alga cells. The obvious inhibition of A. tamarense by marine bacteria at high concentration and evident increase of beta-GlcA in co-colture system would help us in better understanding the relationship between red-tide alga and bacteria, and also enlightened us the possible use of bacteria in the bio-control of red-tide.
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The effect of S-10, a strain of marine bacteria isolated from sediment in the Western Xiamen Sea, on the growth and paralytic shellfish poison (PSP) production in the alga Alexandrium tamarense (A. tamarense) was studied under controlled experimental conditions. The results of these experiments have shown that the growth of A. tamarense is obviously inhibited by S-10 at high concentrations, however no evident effect on its growth was observed at low concentrations. Its PSP production was also inhibited by S 10 at different concentrations, especially at low concentrations. The toxicity of this strain of A. tamarense is about (0.9512.14) x 10(-6) MU/cell, a peak toxicity value of 12.14 x 10(-6) MU/cell appeared on the 14th day, after which levels decreased gradually. The alga grew well in conditions of pH 6-8 and salinities of 20-34 parts per thousand. The toxicity of the alga varied markedly at different pH and salinity levels. Toxicity decreased as pH increased, while it increased with salinity and reached a peak value at a salinity of 30 parts per thousand, after which it declined gradually. S-10 at a concentration of 1.02 x 10(9) cells/ml inhibited growth and the PSP production of A. tamarense at different pH and salinity levels. S-10 had the strongest inhibitory function on the growth of A. tamarense under conditions of pH 7 and a salinity of 34 parts per thousand. The best inhibitory effect on PSP production by A. tamarense was at pH 7, this inhibitory effect on PSP production did not relate to salinity. Interactions between marine bacteria and A. tamarense were also investigated using the flow cytometer technique (FCM) as well as direct microscope counting. S-10 was identitied as being a member of the genus Bacillus, the difference in 16S rDNA between S-10 and Bacillus halmapalus was only 2%. The mechanism involved in the inhibition of growth and PSP production of A. tamarense by this strain of marine bacteria, and the prospect of using it and other marine bacteria in the biocontrol of red-tides was discussed. (c) 2005 Elsevier Ltd. All rights reserved.
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The surface and bottom waters samples were collected from six locations in Xiamen western sea. The quantified estimation of bacterial production (H-3-thymidine method) and observation of bacterial heterotrophic activity (C-14-glucose method) have been made in order to have a better understanding of the role of marine bacteria and their activities. The results showed that the mean value of bacterial heterotrophic activity was 9 X 10(8) cells/(L. h) in the surface waters and 2.6 X 10(8) cells/(L. h) in the bottom waters. The mean value of bacterial production was 38 X 108 cells/( L. h) in the surface waters and 7.1 X 10(8) cells/(L. h) in the bottom waters. The relationship between bacterial production, heterotrophic activity, PCC and DOC measured during this survey were discussed. The good understanding of the relationship between bacteria activity and total coliform was addressed.
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A geochemical study of Bohai Bay surface sediments was carried out to analyze the potential harmful element (PHE: Ge, Mo, In, Sn, Sb,Te, Tl, Bi and V) concentrations, transportation and deposition, enrichment factors and sources. Germanium, Mo, In, Sn, Sb, Te, Tl, Bi and V concentrations in the surface sediments were: 1.43-1.71, 0.52-1.43, 0.04-0.12, 2.77-4.14, 1.14-2.29, 0.027-0.085, 0.506-0.770, 0.27-0.63 and 70.35-115.90 mu g/g, respectively. The distributions of total PHE concentrations, together with sequential extraction analyses, showed that the PHEs were mainly due to natural inputs from the continental weathering delivered to the bay by rivers and atmospheric transportation and deposition. However, high Mo, Sb, Te, Bi and V occurred in non-residual fractions, suggesting some anthropogenic inputs in addition to the natural inputs. Besides sources, the distributions of PHEs were influenced by the coupling of physical, chemical and biological processes. Enrichment factor (EF) was computed for each site for each element in order to assess the polluting elements and the degree of pollution at each site. Results revealed that the EFs were generally lower than 1.0, particularly for Ge, Mo, In, Sn, Tl and V; however, the EFs were higher (>1.5), particularly for Sb, Te and Bi, revealing moderate contamination. (C) 2010 Elsevier B.V. All rights reserved.
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本文以国家“863”计划支持项目“机器人模块化体系结构设计”(编号2007AA041703)为依托,针对模块化机器人研究的难点和热点问题,在广泛调研模块化机器人国内外研究现状的基础上,研究开发了一套关节型模块化机器人样机。本文主要包括以下四方面的工作:1 模块库的建立及拓扑构型研究;2 运动学的研究;3 模块结构设计;4 实验研究。具体工作如下: 分析了模块化与重构性两个概念的区别与联系,在分析一般机电产品的库设计的基础上阐述了面向功能的模块化机器人模块划分原则。在此基础上,建立了含有五种单元模块的模块库,并对其可实现构型进行了拓扑分析。最后,从拓扑构型分析结果中挑选出了20种代表性构型,为基于任务的构型选择奠定了基础。 对关节型模块化机器人的运动学进行了研究,提出了一种新的坐标系建立方法,建立了各模块的运动学变换矩阵,采用运动旋量的指数积公式实现了正运动学分析的模块化,并推导出正运动学公式。对于逆运动学问题,根据推导出的正运动方程和微分运动学公式建立了逆运动学数学模型,并用牛顿—拉夫逊迭代法得出逆运动学迭代公式。 分析了一个六自由度关节型机器人的危险工况,从而确定了机器人运动时各关节所需的最大功率。以此为基础,确定了三种不同功率的旋转模块Rl、Rm、Rs和一个移动模块Tl,并根据功率的计算结果为各模块进行了电机和减速器等器件的选型。最后,以旋转模块Rl为例详细介绍了模块的结构设计过程。 通过软件平台的搭建,对前面章节的拓扑构型的实现及运动学算法进行了仿真验证。通过该软件平台,可以任意选择第二章分析出的拓扑构型,并可以自动生成运动学正解。后以一个六自由度构型为例进行了轨迹规划,验证了软件平台的构型选择,运动学正逆解算法等功能。该仿真中使用的插补算法,既能保证末端执行器的期望路径,又可以实现关节角的平滑过渡。
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The loess-paleosol sequence in China is one of the best archives for studying paleoenvironmental and paleoclimatic processes. The loess deposits in the coast of the Bohai Sea are suitable for the study of aridification in the northern China during glacial periods (fig.2-1). In this paper, stratigraphy was correlated by using magnetic susceptibility, grain size, and thermoluminence (TL) and accelerater mass spectrometer (AMS) ~(14)C ages. Based on the loess records, an interpretation has been made for paleoenvironmental changes on the coast of the Bohai Sea during the last glacials. The results of magnetic susceptibility, grain size, biostratigraphy, TL and ~(14)C dating, suggest that the loess-paleosol sequence in the coast of the Bohai Sea is discontinuous. The loess deposits correlated with the marine δ~(18)O stage 2 are usually absent in some profiles. Also, the thickness of the loess deposits in the same period varied significantly in different sections. In the coast of the Bohai Sea, the higher magnetic susceptibility corresponds to the finer grain size, consistent with the results of the Loess Plateau. It is indicated that the changes in magnetic susceptibility and grain size may record the paleoclimatic fluctuations of the last glacial. Although the loess deposits during the last glacial have been slightly altered by slope runoff, they have still remained main characters as the representative loess deposits of the Loess Plateau. During the last glacial, the less accumulation rate in the coast of the Bohai Sea is similar to that of the desert-loess transition zone in the northwestern Loess Plateau, and the all section contain high concentrations of sand (>60μm), indicate that the aridification in the Bohai Sea occurred during the glacial. But the changes in sand content of loess deposits along a north-south transect of the Bohai Sea and the changes of magnetic susceptibility implicate that desertification might not occur in the shelf of the Bohai Sea during the last glacial. The frequent fluctuations of summer monsoon during the marine δ~(18)O stage 4 are demonstrated by magnetic susceptibility, frequency-dependent susceptibility and the abundance of foraminifera. 46 genera, 71 species of foraminifera were identified from 138 loess samples. Almost all of the foraminifera are present in the last glacial loess, but the distribution patterns of foraminifera show significant temporal changes. The results of magnetic susceptibility, grain size and XRD indicate that not only sea-level changes had influences on foraminifera abundance, but also variations in sediment flux by rivers when sea-level drops might control the abundance of foraminifera. In addition, the diversity and exquitability of the foraminifera suggest that the frequent fluctuations of foraminifera fossil abundance during the marine δ~(18)O stages could be partly attributed to leaching. In summary, the changes in foraminifera of abundance related to the paleoclimatic variations, and the aridification extends to the coast of the eastern China during the last glacial.
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The main research projects reported in this paper are the establishment of a luminescence (OSL/TL) dating laboratory in The Institute of Geology and Geophysics, CAS, and studies on OSL dating technique and protocol of sediments from North China. These projects have been suggested in order to fit in with the needs of research developments in environmental changes, in particular the aridity and desertification in North China. A new luminescence dating laboratory in which there are a Rise TL/OSL-DA-15B/C reader with Sr-90 beta source, a set of Little More Tape 9022 alpha and beta irradiators, three set of Daybreak 583 intelligent alpha counters and sample preparation system has been set up in the Institute in June 2001. The courses of the establishment of a new laboratory involved a series of technical works, besides making a suitable choice of the equipment, as follows: installing and testing TL/OSL reader, calibrating the dose rate of the beta and alpha sources in the irradiators with the standard sources, testing and calibrating the count rates of the thick source alpha counting in the alpha counters with a standard sample, and then dating of the know age samples to check and examine the OSL/TL dating system. All data obtained from above calibrations and tests show that the established OSL/TL system, including the used equipment in it, can be used to determine age of the geological and archaeological samples with an error of equivalent dose (De) of less than 5%. The OSL dates of several sediment samples obtained from the system are good agreement with those from the OSL dating laboratory in Hong Kong University and ~(14)C dates within 1 - 2 standard deviations. The studies on OSL dating technique and protocol of sediment samples being in progress involve the De determinations with single aliquot regeneration (SAR) (Murray and Wintle, 2000) of the coarse grain quartz from sand dune samples and comparison of the De determinations obtained from SAR with those measured by using multiple aliquot regeneration of loess fine grains. The preliminary results from these research works are shown as follows. The very low natural equivalent dose (De) of about 0.012 - 0.03 Gy, corresponding age of less than 10 years, for BLSL (blue light stimulated luminescence) of the coarse grain quartz from modern sand dune samples in Horqin sand fields has been determined with both the SAR and multiple aliquot regeneration (MAR) techniques. This imply that the BLSL signal zeroing of the quartz could be reached before burying of the sand in Horqin sand fields. The De values and ages of the coarse grain quartz measured with SAR protocol are in good agreement with those obtained from multiple aliquot technique for the modern sand dune samples, but the errors of De from the MAR is greater than those from the SAR. This may imply that the higher precision of age determination for younger sand dune samples could be achieved with the SAR of coarse grain quartz. The MAR combining with "Australian Slide method" may be a perfect choice for De measurements of loess fine grain samples on the basis of analysis of De values obtained from the SAR and from the MAR. The former can be employed to obtain a reliable age estimate of loess sample as older as approximately SO ka BR There is a great difference between De determinations from the (post-IR) OSL of the SAR (Roberts and Wintle, 2001) and those from independent or expected estimates for the older samples. However, the age estimates obtained from the (post-IR) OSL of the SAR are mostly closed to the independent age determinations for the younger (age less than 10 ka) fine grain samples. It may be suggested that the (post-IR) OSL of the SAR protocol of the fine grain fraction would be a suitable choice to dating of the younger samples, but may be unsuitable for the older samples.
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Using knowledge of geology, geochemistry, coal petrology, mineralogy, by means of a variety of advanced measuring methods such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled atomic emission spectrometry (ICP-AES), X-ray powder diffraction (XRD), scanning electron microscopy with energy-dispersive spectrometer(SEM-EDS), sequential chemical extract and density fractions, the characteristics of trace elements and minerals in Jurassic Beipiao coal mine under inland limnetic sedimentary environment and in late Permian Jianxin and Qiaotou coal mines under paralic swamp sedimentary environment were studied. Compared with the average concentration in the world bituminous coals, the Beipiao coal was characterized by relatively high contents of Sc, Ti, Cr, Co, Ni, Zn, Se, Sr, Zr, Y, Ba, REE and Th, and lower contents of V, Rb, Cd, Sn, Pb, Bi and U; while the Jianxin coal was relatively enriched in Li, Sc, Ga, Sr, Y, Nb, Sb, Th and U, with low concentration of Be, Co, Ni, Cu, Ge, Zr, Mo, Cd, Cs, Ba, Pb and Bi; and the Qiaotou coal was enriched in Li, Sc, Sr, Nb, Ta, Zr, REE, Hf, Th and U, with low concentration of Be, V, Co, Ni, Cu, Ge, Mo, Cd, Cs, Ba, Tl, Pb and Bi. The concentrations of Ca, Mg and K in Beipiao coal are higher than those in Jianxin coal and Qiaotou coal, while Fe, S and Ti in Beipiao coal are lower than those in Jianxin coal and Qiaotou coal. The proximate analysis of coal samples was carried out, which indicated that Beipiao coal was medium- to high- ash (5.92-60.68%) with low sulphur coal, and Jianxin coal and Qiaotou coal was medium to high ash (8.85-46.33%) with high sulphur. The reflectivity was measured, which explained that Beipiao coal belonged to high volatile bituminous coal, Jianxin coal was low volatile bituminous coal and Qiaotou coal was low volatile anthracite. Quantitative maceral analyses were studied. The characteristics of rare earth elements (REE) were investigated, which showed that the total contents of REE were higher than that of the world's average content. With the increase of coal's metamorphic grade, the total contents of REE decreased from 98.5 X 10"6 of Beipiao coal to 94.2 X 10"6 of Jianxin coal, and to 75.9 X 10"6 of Qiaotou coal, and 5Eu reduced which indicated that the element Eu depleted. The characteristics of REE was controlled by the metamorphic grade of coal. And REE were mainly absorbed in clay minerals in Beipiao coal samples, while in Jianxin and Qiaotou coal mines, REE were primarily related to clay mineral and pyrite. The variation of trace elements in vertical direction of coal seams was studied, and the results showed that different trace elements differed greatly. The correlation between trace elements and ash were determined. Four major trace elements (aluminium-silicates, sulphide, carbonate and phosphate) accounted for the occurrence and distribution of most elements studied were determined. Coal samples were separated by density fraction, which showed that Cr, Cu, Mo and Pb were closely related to inorganic matters mainly distributed in P >2.6 and dropped remarkably in the density fractions P <2.3 . The occurrences of Co, Cr, Ni, As, Se, Mo, U were studied directly and quantitatively using sequential chemical extract with six steps, which showed that Co. Ni, Mo and U were mainly in the form of mineral, and As, Se chiefly in the form of organic state, while Cr mostly in the form of organic state and mineral. Major mineral phases presented in the Beipiao coal were Kaolinite, illite, quartz, calcite, and small amount of siderite, barite. While major mineral phases in Jianxin and Qiaotou coal were pyrite, kaolinite, and small amount of marcasite, rutile, sphalerite. This is the first time that the chromite in the coal was discovered in China, which indicates that Cr occurrence appeared in the form of chromite. The ratio of Sr/Ba, Sr/Ca and V/Ni in Beipiao coal mine under inland limnetic is smaller than that of in Jianxin and Qiaotou coal mines under paralic swamp. The ratio of K/Na and Th/U of Beipiao coal mine is higher than that of Jianxin and Qiaotou coal mine, which proved that Beipiao coal was not affected by sea water and Jianxin and Qiaotou coal were affected by sea water. Trace elements such as Cr, Ni, Mo in minerals were analyzed by SEM-EDS. The factors controlling the enrichment of trace elements can be divided into syngenetic stage factors and epigenetic stage factors.
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黔西南滥木厂铊矿化区河流沉积物中重金属元素的含量很高,其环境污染和生态危害值得关注。本文采用地质累积指数( Igeo ) 和潜在生态危害指数(RI) 对重金属污染及其潜在生态危害进行了评价。结果表明,滥木厂河流沉积物中重金属存在较强程度的污染,并具有较强程度的潜在生态危害。主要的污染元素为Tl 、As 和Cd ,而Cr 、Zn、Pb、Cu 基本上处于无污染或轻微污染的水平。河流沉积物重金属的污染在上游河段较下游河段严重。重金属平均潜在生态危害的排序为:矿山影响区Tl > Cd > As > Pb > Cr > Cu > Zn ;矿山未影响区Cd > Tl > Pb > Cr > As > Cu > Zn。
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分散元素Te、Se、Cd、Tl在某些类型金矿中可以富集,是黄金找矿的重要指示元素,甚至是最重要的指示元素。Te、Se主要富集在与碱性岩浆活动有关的金矿中, Cd主要富集在火山热液型金矿和古老结晶基底内的糜棱岩型金矿中,而Tl则在卡林型金矿中富集。分散元素在金矿床中的地球化学信息丰富了黄金找矿方法理论,拓宽了找矿思路。
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铊(Tl) 是一个典型的毒害金属元素,其对哺乳动物的毒性高于Hg、Cd、Cu、Pb、Zn 等元素。Tl 在自然水体中存在两种氧化状态:Tl + 和Tl3 + ,通常主要以Tl + 形式存在。Tl + 易随地下水或地表水的流动而迁移到更远的距离,但在较强的氧化环境中,Tl + 能够氧化成Tl3 + 形成Tl (OH) 3 的沉淀,可以制约水环境中Tl 的总含量。Tl 可以通过饮用水进入人体,其中Tl + 在人体的酶化反应过程中可以置换K+ ,并与酶产生很强的亲和力,从而诱发Tl 的毒害效应。活性铝净化法、离子交换法和NaCl 溶液可以用来去除饮用水中的Tl 。基于Tl 的毒害性,Tl 所产生的水环境问题应该引起重视。
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重庆城口地区从震旦统到下寒武统发育有丰富的黑色岩系,20世纪末期在该地区黑色岩系中开展了大量的铂族元素(PGE)的找矿工作,但是由于种种原因,关于该地区是否存在PGE矿化异常,还没有得到最终的结论。本次研究在PGE分析方法论证的基础上,进行了大量样品的PGE分析和微量元素分析。主要结论如下:①区域上上震旦统槽区和断块区两套黑色岩系在原始的沉积环境和物源供给上有较大的差异,虽然槽区上震旦统的黑色岩系具有和下寒武统黑色岩系相似但强度较低的V-Cu-Y-Mo—U异常,但基本上不具有明显的PGE-Au-Ag异常。②断块区水井沱组黑色岩系:和平剖面西段新发现的U-V-Mo-PGE异常可能是今后工作的重点,Pt+Pd最高达248.9×10^-9,局部U-V都达到了工业品位。③槽区巴山组硅质岩:四个剖面都揭示了在硅质岩中广泛存在连续的PGE异常,87个碳质硅质岩平均含Pt+Pd 57.2×10^-9,有10个样品Pt+Pd〉100×10^-9,最高达196.5×10^-9;大部分碳质硅质岩都具有不同程度的V-Cu-Y-Mo-Tl-U组合异常,V都达到了独立矿床的品位要求,其中猪草河、燕子河等剖面还存在厚度较大的富矿地段,特别是燕子河剖面,局部还存在REE+Y的高异常,值得深入研究。④城巴地区下寒武统黑色岩系存在广泛的PGE异常,但没有达到PGE的矿化要求,建议加强该地区的钒矿和铀矿勘探研究,PGE可以综合评价。