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341.
DCS-偶氮胂光度法测定钛酸锶烧结物中游离的氧化锶胡浩,周宏实江苏海安磷肥厂226600DCS-偶氮肿[2-(2-胂酸基苯偶氮)-7-(2,6-二氯-4-磺酸基苯偶氮)-1,8-二羟基-3,6-二磺酸萘]属双偶氮变色酸类显色剂,主要用于稀土元素的高灵... 相似文献
342.
计算极谱法同时测定镉镍的研究 总被引:1,自引:0,他引:1
采用普通极谱仪与计算机联机技术,用卡尔曼滤波处理以KSCN为支持电解质的Cd~(2+)和Ni~(2+)混合溶液的示波极谱重叠波。实验表明,极谱可逆波具有较好的加和性,可采用计算极谱方法对多组分(尤其是难以分开的重叠波)进行同时测定。 相似文献
343.
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345.
Summary A new computation method is described which determines the focal coordinates, theP
n-andP
G-velocity, the focal time and the Moho-depth in the case of near earthquakes. The method is provided especially for areas where the crustal parameters are insufficiently known. It presumes that the standard error ofP
n-andP
G-arrival times is a minimum. The problem turns out to represent the solution of a set of at least seven equations with seven unknown parameters. Four of these unknowns can be separated in advance. This leads to a considerable simplification. The three remaining unknowns are the focal coordinates. Their best fitting values are found by the gradient method. An example is presented which shows how errors can arise if the initial trial coordinate is chosen at an unfavourable position. 相似文献
346.
Four integral-based methods for the inversion of gravity disturbances, derived from airborne gravity measurements, into the disturbing potential on the Bjerhammar sphere and the Earths surface are investigated and compared with least-squares (LS) collocation. The performance of the methods is numerically investigated using noise-free and noisy observations, which have been generated using a synthetic gravity field model. It is found that advanced interpolation of gravity disturbances at the nodes of higher-order numerical integration formulas significantly improves the performance of the integral-based methods. This is preferable to the commonly used one-point composed Newton–Cotes integration formulas, which intrinsically imply a piecewise constant interpolation over a patch centered at the observation point. It is shown that the investigated methods behave similarly for noise-free observations, but differently for noisy observations. The best results in terms of root-mean-square (RMS) height-anomaly errors are obtained when the gravity disturbances are first downward continued (inverse Poisson integral) and then transformed into potential values (Hotine integral). The latter has a strong smoothing effect, which damps high-frequency errors inherent in the downward-continued gravity disturbances. An integral method based on the single-layer representation of the disturbing potential shows a similar performance. This representation has the advantage that it can be used directly on surfaces with non-spherical geometry, whereas classical integral-based methods require an additional step if gravity field functionals have to be computed on non-spherical geometries. It is shown that defining the single-layer density on the Bjerhammar sphere gives results with the same quality as obtained when using the Earths topography as support for the single-layer density. A comparison of the four integral-based methods with LS collocation shows that the latter method performs slightly better in terms of RMS height-anomaly errors. 相似文献
347.
One or two gram aliquots of twelve reference materials with low platinum-group element (PGE) abundances (Ir concentrations ranging from 30 to 510 pg g-1 ) were analysed by isotope dilution ICP-MS using an on-line chromatographic matrix separation after acid digestion in a high pressure asher (HPA-S) to determine the concentrations of Ru, Pd, Re, Ir and Pt. Osmium concentrations were determined via ID-ICP-MS but as volatile OsO4 , whereas Rh concentrations were calculated by comparing the peak areas of the chromatographic peak with that of a standard solution. Validation of the method was performed and the concepts of traceability and measurement uncertainty were applied to assure comparability. The reference materials BCR-2, BHVO-1, BHVO-2, BIR-1, DNC-1, EN026 10D-3, MAG-1, RGM-1, SCo-1, SDO-1, TDB-1 and W-2 were investigated to test for their usefulness for certification. The use of TDB-1 is highly recommended because it is homogeneous at the two gram level and many values based on several different analytical procedures have been published. It is recommended that our efforts should focus on the certification of this reference material to reduce the uncertainties of its currently certified values (Pd and Pt only) and to assign certified values to the other PGE and Re. It is necessary to have at least one well-characterised RM for validation of methods applied to the analysis of PGE and Re in low abundance samples, although the matrix of TDB-1 might not completely match those of many samples. 相似文献
348.
Li Bing Ma Xinrong Han Lirong Yang Hongxia 《Geostandards and Geoanalytical Research》2004,28(2):317-323
A simple sample treatment method for the accurate and precise determination of iodine in soil, sediment and biological samples by inductively coupled plasma-mass spectrometry (ICP-MS) is described. Iodine in samples was extracted in screw top PTFE-lined stainless steel bombs using a 10% v/v ammonia solution at 185 C for 18 hours (overnight), after which the extract was introduced into the ICP-MS for direct measurement. 126 Te was employed as the internal standard to compensate for matrix effects and instrument drift. The limit of detection (LOD, three times the standard deviation of the procedural blank solution, expressed as the concentration in the sample solution) was 0.003 ng ml--1 . The limit of quantitation (LOQ, ten times the standard deviation of the procedural blank solution, expressed as the concentration in the solid samples, dilution factor DF = 100) was 0.01 μg g--1 (dry mass). The accuracy and precision of the method were demonstrated by analysing different Chinese geological certified reference materials (soils, stream sediments and a hair sample). The measured concentrations were in a good agreement with the certified values indicating that bias in the method was not significant. The precision (n = 10) for different concentrations ranged from 1.82% to 4.32% RSD. Comparison of the ammonia extraction procedure with a "sintering" method indicated that there was no significant difference in results obtained with the two methods for geological soil and stream sediment samples. However, for biological samples, such as hair, kelp, tea etc., the results obtained by the sintering method were far below those of the ammonia extraction method. The ammonia extraction has advantages, as it is simpler than the "sintering" method, and has a lower procedural blank, better detection limits and reproducibility. Due to the simplicity of the method, a high rate of sample throughput is possible. 相似文献
349.
给出了双星姿态测量的两种算法,并从几何和代数两个方面证实其存在双值问题;探讨了双值问题与精度衰减因子(DOP)之间的关系,并提出了双值问题的解决方案。 相似文献
350.
辽河断陷以碳酸盐岩和砂页岩为主的古潜山地层一直全部划归中、新元古界。由于在该套地层的部分岩石薄片中发现交代残余的动物化石碎片,因此提出辽河断陷有古生界存在的新观点。通过牙形石、微古植物、动物化石和岩性组合的研究,对这套地层进行了重新厘定,建立了古生代寒武纪、奥陶纪、石炭纪和二叠纪地层层序。研究成果表明,辽河断陷存在古生界储层,古生代潜山并非单斜.而是由被断裂改造的褶皱组成的断块。这一成果为重新认识潜山的内幕构造特征和油气储层分布规律奠定了基础。 相似文献