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461.
乙醇介质制备载炭泡塑及其在地质样品金测定中的应用 总被引:2,自引:2,他引:0
载炭泡塑相较于无负载泡塑,可有效提高泡塑对金的吸附能力,但现有制备载炭泡塑的方法制备效率不高。为了缩短制备载炭泡塑的时间,提高制备效率,本文采用活性炭-乙醇溶液制备载炭泡塑,通过优化制备条件,包括负载介质的种类、试剂浓度、浸泡时间,使得制备100个载炭泡塑的时间可以控制在30 min之内,并结合ICP-OES建立了测定地质样品中金的方法。实验结果表明:该方法的振荡时间可以缩短至20 min。金的质量浓度在0~100. 00μg/mL范围内与光谱强度呈良好的线性关系,相关系数为0. 9997,方法检出限(3σ)为0. 0066μg/g,测定结果相对标准偏差为0. 81%~2. 11%(n=10)。该方法经4个国家标准物质验证,准确度与精密度良好,能够满足地质样品中金的分析测试要求。 相似文献
462.
Vertical and horizontal distribution of fluorescent dissolved organic matter in the Southern Ocean 总被引:3,自引:0,他引:3
Youhei Yamashita Ayumi Tsukasaki Tamihito Nishida Eiichiro Tanoue 《Marine Chemistry》2007,106(3-4):498-509
The vertical and horizontal distribution of fluorescent dissolved organic matter (FDOM), determined by fluorescence intensity at 320 nm excitation and 420 nm emission, were clarified in nine stations on two transects at the Southern Ocean, including a subtropical, subantarctic, polar frontal and Antarctic zone. All vertical profiles of fluorescence intensity showed that levels were lowest in the surface waters, increased with increasing the depth in mid-depth waters ( 2000 m), and then stayed within a relatively narrow range from there to the bottom. Such vertical profiles of FDOM were similar to those of nutrients, but were adverse to dissolved oxygen. In water columns below the temperature-minimum subsurface water (dichothermal waters) in the Antarctic zone and below the winter mixed layer in the other zones, we determined the relationships of fluorescence intensity to concentrations of nutrients and apparent oxygen utilization (AOU) over the entire area of the present study, and found significant linear correlations between the levels of fluorescence intensity and nutrient concentrations (r = 0.70 and 0.71 for phosphate and nitrate + nitrite, respectively) and AOU (r = 0.91). From the strong correlation coefficient between fluorescence intensity and AOU, we concluded that FDOM in the Southern Ocean is formed in situ via the biological oxidation of organic matter. The regeneration of the nutrients/consumption of the oxygen/formation of FDOM was active in mid-depth waters. However, the correlations between fluorescence intensities and nutrients and AOU were different in the mid-depth water masses, Subantarctic Mode Water (SAMW), and Antarctic Intermediate Water (AAIW), indicating that the sources of organic matter responsible for FDOM formation were different. A considerable amount of FDOM in the SAMW is thought to be produced by the remineralization of DOM in addition to sinking particulate organic matter, while DOM is less responsible for FDOM formation in the AAIW. 相似文献
463.
Frank Postberg Eberhard Grün Mihaly Horanyi Sascha Kempf Harald Krüger Jürgen Schmidt Frank Spahn Ralf Srama Zoltan Sternovsky Mario Trieloff 《Planetary and Space Science》2011,59(14):1815-1825
Classical methods to analyze the surface composition of atmosphereless planetary objects from an orbiter are IR and gamma ray spectroscopy and neutron backscatter measurements. The idea to analyze surface properties with an in-situ instrument has been proposed by Johnson et al. (1998). There, it was suggested to analyze Europa's thin atmosphere with an ion and neutral gas spectrometer. Since the atmospheric components are released by sputtering of the moon's surface, they provide a link to surface composition. Here we present an improved, complementary method to analyze rocky or icy dust particles as samples of planetary objects from which they were ejected. Such particles, generated by the ambient meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons and planets. The planetary bodies are enshrouded in clouds of ballistic dust particles, which are characteristic samples of their surfaces. In situ mass spectroscopic analysis of these dust particles impacting onto a detector of an orbiting spacecraft reveals their composition. Recent instrumental developments and tests allow the chemical characterization of ice and dust particles encountered at speeds as low as 1 km/s and an accurate reconstruction of their trajectories. Depending on the sampling altitude, a dust trajectory sensor can trace back the origin of each analyzed grain with about 10 km accuracy at the surface. Since the detection rates are of the order of thousand per orbit, a spatially resolved mapping of the surface composition can be achieved. Certain bodies (e.g., Europa) with particularly dense dust clouds, could provide impact statistics that allow for compositional mapping even on single flybys. Dust impact velocities are in general sufficiently high at orbiters about planetary objects with a radius >1000 km and with only a thin or no atmosphere. In this work we focus on the scientific benefit of a dust spectrometer on a spacecraft orbiting Earth's Moon as well as Jupiter's Galilean satellites. This ‘dust spectrometer' approach provides key chemical and isotopic constraints for varying provinces or geological formations on the surfaces, leading to better understanding of the body's geological evolution. 相似文献
464.
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466.
于1989年1月 - 1989年8月采用连续培养和半连续培养方法进行了伪矮海链藻细胞分裂、叶绿素a含量和活体荧光特性与光、营养盐关系的研究。结果表明,细胞分裂、活体荧光、叶绿素a均呈现光照期的增长速率明显高于黑暗期的增长速率的日变化规律,荧光增强比则在光照期开始后或黑暗期结束时出现最高值;光强和营养盐不仅影响各指标日变化的幅度,而且还可改变荧光增强比峰值出现时间。因此,在研究细胞分裂、叶绿素a和荧光特性的昼夜节律时,必须考虑光和营养盐这两个重要因素。 相似文献
467.
468.
W. Kalkreuth N. Sherwood G. Cioccari Z. Corrêa da Silva M. Silva N. Zhong L. Zufa 《International Journal of Coal Geology》2004,57(3-4):167-185
Combining vitrinite reflectance (VR) and fluorescence alteration of multiple macerals (FAMM) analyses provide insights into the chemical nature of vitrinites (i.e., perhydrous vs. orthohydrous vs. subhydrous compositions) in Permian Gondwana coals of the Paraná Basin, Brazil. The FAMM-derived equivalent VR (EqVR) values and relationships with VR can be determined according to calibration curves based largely on Permian Gondwana coals of eastern Australia.The analytical results indicate that vitrinites in the Paraná Basin coals studied generally range from orthohydrous to perhydrous, with interpreted VR suppression ranging up to 0.2% absolute for the most perhydrous case. The EqVR values of the Santa Catarina coals, which range from about 0.85% to 0.95% differ from VR values by about 0.10–0.15% absolute, potentially having significant implications on coal utilization.The causes of vitrinite reflectance suppression in the Paraná Basin coals are as yet poorly understood, but are likely to be related to a combination of factors. 相似文献
469.
ZHAO Guiping LIU Shuwen LIU Xiaohan Computational Geodynamics Laboratory Graduate School of Chinese Academyof Sciences Beijing School of Earth Space Sciences Peking University Beijing Institute of Geology Geophysics Chinese Academy of Sciences Beijing 《《地质学报》英文版》2004,78(1):186-190
Although porphyroblast microstructures play an important role in structural and metamorphic studies, there are still controversies in the interpretation. The focus is how porphyroblasts grow during deformation and metamorphism. In this paper, we introduce a new approach, the Synchrotron Radiation X-Ray Fluorescence, to a hemi-quantitative interpretation of the growth mode of porphyroblasts. The analysis was done at the Beijing Synchrotron Radiation Facility. The specimens were sampled from metapelite of the Baoyintu Group, northern Urad Middle Banner, Inner Mongolia. The new method is successful for determining the microscopic distribution of trace elements in porphybroblasts. The results support the theory of deformation partition, which has been brought forth by Bell and his colleagues, and demonstrate the existence of porphyroblast growth phases and the growth mode of porphyroblasts by hemi-quantitative mineral chemical analysis. The porphyroblast grows stage by stage in the manner of the distribution 相似文献
470.
近年来,中国的各种传媒上不断出现有关夜明珠的报道。引起了广泛的注意,当前市场上出现的夜明珠主要是荧石夜明珠,笔者对荧石夜明珠作了一些初步研究和探讨。发光的原因主要是含稀土元素(rare earth elements)所致,含量可以低至万分数。本文的资料希望能促进对夜明珠问题的深入认识。 相似文献