Probing variations in fundamental constants with radio and optical quasar absorption-line observations     

P. Tzanavaris †  M. T. Murphy  J. K. Webb  V. V. Flambaum  S. J. Curran 《Monthly notices of the Royal Astronomical Society》2007,374(2):634-646

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The redshift distribution of absorption-line systems in QSO spectra     

A. I. Ryabinkov  A. D. Kaminker †  D. A. Varshalovich 《Monthly notices of the Royal Astronomical Society》2007,376(4):1838-1848

A statistical analysis of the space–time distribution of absorption-line systems (ALSs) observed in QSO spectra within the cosmological redshift interval   z = 0.0–3.7  is carried out on the base of our catalogue of absorption systems ( Ryabinkov et al. 2003 ). We confirm our previous conclusion that the z -distribution of absorbing matter contains non-uniform component displaying a pattern of statistically significant alternating maxima (peaks) and minima (dips). Using the wavelet transformation, we determine the positions of the maxima and minima and estimate their statistical significance. The positions of the maxima and minima of the z -distributions obtained for different celestial hemispheres turn out to be weakly sensitive to orientations of the hemispheres. The data reveal a regularity (quasi-periodicity) of the sequence of the peaks and dips with respect to some rescaling functions of z . The same periodicity was found for the one-dimensional correlation function calculated for the sample of the ALSs under investigation. We assume the existence of a regular structure in the distribution of absorption matter, which is not only spatial but also temporal in nature with characteristic time varying within the interval 150–650 Myr for the cosmological model applied.  相似文献   

辽东湾水体吸收系数区域性半分析反演算法     

苏园园  丘仲锋  张艳萍 《海洋科学》2015,39(4):73-81

水体吸收系数是影响水体光场分布的重要参数,在水色遥感探测中受到广泛关注。本文利用2012年9月辽东湾区域航次调查数据分析该区域水体各组分吸收系数的分布情况,结果表明,辽东湾水体中浮游植物含量相对较高。并利用该航次数据,建立了区域性半分析算法,该算法基于相邻波段间固有光学量的线性关系,首先通过遥感反射率反演得到550 nm波段的水体总吸收系数,再通过后向散射波段相关关系外推得到其他波段的总吸收系数。经独立测试数据检验,3个波段(412、443、550 nm)总吸收系数反演的平均相对误差分别为19.71%,17.99%,9.35%,说明区域性半分析算法能较好地估算研究区域的水体总吸收系数。本文还通过引入随机误差对算法稳定性进行了检验,结果表明算法具有较好的稳定性。  相似文献   

章丘大葱特征元素农业地球化学研究          下载免费PDF全文

赵西强  王存龙  王红晋 《山东国土资源》2015,31(1):55-58

以章丘大葱产区生态地球化学调查为基础,采集了表层土壤、大葱、根系土及出露的代表性岩石样品,实测了大量和微量营养元素的含量,查明了研究区土壤地球化学背景。通过计算大葱对土壤营养元素的吸收率及大葱品质与营养元素的相关性分析,查明了大葱生长的特征营养元素为N,K2O,Zn,B,P,Cu,Mn。在岩石-土壤-大葱这一生态体系中,营养元素在土壤中保持一定的储备和积累,为大葱的生长提供了有利的农业地球化学环境。  相似文献   

水体富营养化状态对城市河道底泥吸附/释放P的影响——以江苏省苏州市河道试验研究为例     

冯海艳  李文霞  杨忠芳  阮晓红 《中国区域地质》2010,(5):739-744

以苏州古城区内的河道为研究对象,采用静态培养的方式,研究了上覆水体不同富营养化程度对底泥中P释放/吸附的影响。研究结果表明：截断外源污染后,苏州河道底泥对水体中营养盐P呈现吸收状态;随着上覆水体磷酸盐浓度的增大,单位面积底泥累积吸收的磷酸盐就越多;上覆水与底泥比值越大,底泥对P的吸附率有减小的趋势。  相似文献   

俄罗斯水热法合成祖母绿的宝石学特征研究     

孙主  李娅莉 《地质科学译丛》2010,(1):12-15,42,I0002

俄罗斯水热法合成祖母绿是珠宝界较关注的产品。选用5粒俄罗斯水热法合成祖母绿样品进行了常规宝石学特征测试、电子探针成分分析、红外吸收光谱和紫外-可见吸收光谱测定。结果表明,俄罗斯水热法合成祖母绿样品以低碱、富Fe与Cr为特征,折射率和相对密度明显偏高,红外吸收光谱特征峰出现在4052cm叫附近;俄罗斯水热法合成祖母绿样品的致色元素为Cr与Fe。同时,对比分析了俄罗斯、桂林水热法合成祖母绿样品和天然祖母绿样品的宝石学特征。  相似文献   

低氧低分压环境下泡塑吸附-石墨炉原子吸收光谱法测定化探样品中的痕量金   总被引：2，自引：1，他引：1  

王祝  邵蓓  邬国栋  李明礼 《岩矿测试》2010,29(3):282-286

针对西藏低氧低分压环境下痕量金的测定,探讨了溶矿介质、解脱时间、吸附温度、Fe3+加入量等对测定结果的影响。确定了最佳测定条件,并较详细讨论了Fe3+在溶矿和吸附过程中的重要作用。方法检出限为0.102 ng/g,测定范围为0.24~300 ng/g,准确度(ΔlgC,n=12)为0.01~0.03,精密度(RSD,n=12)为1.61%~7.33%,很好地解决了西藏地区低氧低分压低温环境下痕量金测定的技术难题。  相似文献   

土壤中单环芳烃定量分析的基质效应研究   总被引：1，自引：0，他引：1  

刘菲  王媛媛  陈家玮 《岩矿测试》2010,29(5):481-485

来源于燃料油泄露的单环芳烃对土壤的污染已经成为一个很普遍的现象,因此,准确、高效地检测土壤中的挥发性单环芳烃是一个很关键的问题。文章通过在标准系列中加入石英砂和土壤两种基质,比较水、水-石英砂、水-土壤3个定量库中得到的标准曲线的斜率,研究基质效应对土壤样品定量的影响。结果表明,芳香烃类物质在土壤基质中的斜率总体小于在石英砂基质中的斜率,在石英砂基质中的斜率比在水基质中的斜率小1%(苯)～9%(正丁苯),在水基质中得到的斜率最大;只有苯在土壤基质和水基质中的斜率相当,其余组分在土壤基质中的斜率比在水基质中的斜率小9%(丙苯)～24%(1,2,4-三氯苯)。单环芳烃在土壤基质中相对斜率的大小与化合物本身的沸点以及辛醇-水分配系数呈负相关。研究表明,在对土壤样品进行校准的过程中,选择合适的基质建立定量库是一个非常关键的因素。  相似文献   

Seasonal dynamics of light absorption by chromophoric dissolved organic matter (CDOM) in the NW Mediterranean Sea (BOUSSOLE site)     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

We analyze a two-year time-series of chromophoric dissolved organic matter (CDOM) light absorption measurements in the upper 400 m of the water column at the BOUSSOLE site in the NW Mediterranean Sea. The seasonal dynamics of the CDOM light absorption coefficients at 440 nm (a_cdom(440)) is essentially characterized by (i) subsurface maxima forming in spring and progressively reinforcing throughout summer, (ii) impoverishment in the surface layer throughout summer and (iii) vertical homogeneity in winter. Seasonal variations of the spectral dependence of CDOM absorption, as described by the exponential slope value (S_cdom), are characterized by highest values in summer and autumn at the surface and low values at the depths of a_cdom(440) subsurface maxima or just below them. Variations of a_cdom(440) are likely controlled by microbial digestion of phytoplankton cells, which leads to CDOM production, and by photochemical destruction (photobleaching), which leads to CDOM degradation. Photobleaching is also the main driver of S_cdom variations. Consistently with previous observations, a_cdom(440) for a given chlorophyll a concentration is higher than expected from Case I waters bio-optical models. The total non-water light absorption budget shows that surface waters at the BOUSSOLE site are largely dominated by CDOM during all seasons but the algal bloom in March and April. These results improve the knowledge of CDOM absorption dynamics in the Mediterranean Sea, which is scarcely documented. In addition, they open the way to improved algorithms for the retrieval of CDOM absorption from field or satellite radiometric measurements.  相似文献   

Correlation between the mean matter density and the width of the saturated Lyα absorption     

Hu Zhan 《Monthly notices of the Royal Astronomical Society》2003,344(3):935-941

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