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Attitude determination is a significant aspect of the navigation technology. The determination of the attitudes based on accelerometer and magnetometer fusion is basically an applied mathematical problem. In this article, we obtained the proposed quaternionic symbolic solution for accelerometer and magnetometer fusion which is quite different from existing methods. The proposed symbolic solution has the advantages of high accuracy and consumes much less time. Besides, the normalization problem of input data was discussed. Biquaternions ware introduced to describe the existence of the complex quaternion. Several experiments were carried out to verify the proposed symbolic solution. [ABSTRACT FROM AUTHOR]

The aim of this study is to characterize plutonium sorption particularly Pu distribution coefficients and the influence of pH on sorption processes in saturated geological materials used as a radioactive waste repository in China. The examined geological media is from a southwestern Chinese repository and consists of soil and slates. The backfill material consists of Na-bentonite from Inner Mongolia Gaomiaozi, and will be used at the Beishan high-level waste (HLW) repository, Gansu Province. The results show that the sorption capacity of Pu by geological medium in an acidic environment is low, but significantly increases with increasing pH. [ABSTRACT FROM AUTHOR]

An improved threshold shift-invariant wavelet transform de-noising algorithm for high-resolution gamma-ray spectroscopy is proposed to optimize the threshold function of wavelet transforms and reduce signal resulting from pseudo-Gibbs artificial fluctuations. This algorithm was applied to a segmented gamma scanning system with large samples in which high continuum levels caused by Compton scattering are routinely encountered. De-noising data from the gamma ray spectrum measured by segmented gamma scanning system with improved, shift-invariant and traditional wavelet transform algorithms were all evaluated. The improved wavelet transform method generated significantly enhanced performance of the figure of merit, the root mean square error, the peak area, and the sample attenuation correction in the segmented gamma scanning system assays. We also found that the gamma energy spectrum can be viewed as a low frequency signal as well as high frequency noise superposition by the spectrum analysis. Moreover, a smoothed spectrum can be appropriate for straightforward automated quantitative analysis. [ABSTRACT FROM AUTHOR]

Abstract: The previous radon migration experimental research object is for the most of radon gas in underground migration or the migration of air interface. By using the method of active carbon accumulated measuring radon, this thesis adjusts air pressure to study the migration regularity of radon. The paper measures the concentration distributions of radon in airtight vertical glass tube under the same temperature, humidity, different cumulative times and different pressure in vacuum (respectively for -0.06MPa, -0.05MPa, -0.04MPa, atmospheric conditions).Basing on the migration equations of radon gas in the air and the concentration distribution of radon under different gas pressure, the paper estimates the average speed of radon gas under different pressures. Through series experiments, following conclusions can be obtained: the migration velocity of radon in the air is related with the air pressure: with greater air pressure, the conveyance speed is faster. Especially at low-pressure state the downward migration is more apparent. The average speed of radon in different pressures cases are estimated that compliance of the calculation results and the actual measurement was good results. [Copyright &y& Elsevier]

Abstract: The paper studies the adsorption features of 239Pu in phyllitic slate and clay media through static experiment method. The two different geo-media were collected from a site for disposing very low level waste (VLLW) as experimental samples. Experimental results have shown that an adsorption equilibrium time of 239Pu in phyllitic slate and clay is approximately 10 days, and the adsorption coefficient (Kd) B Bvalues of phyllitic slate and clay are about 6000ml/g and 2700ml/g, respectively. The experimental result of particle size effect indicates when adsorption of plutonium in particle samples increases, the KBdB values of these two geo-media increase while the particles decrease in size. And the experimental impact on aqueous phase pH value reveals that Kd of 239Pu in creases at higher aqueous phase pH value, illustrating stronger adsorption capacity. Experimental data are also measured through the curve fitting, KBdB values are thus obtained theoretically. [Copyright &y& Elsevier]

Clustering analysis is a promising data-driven method for analyzing functional magnetic resonance imaging (fMRI) time series data. The huge computational load, however, creates practical difficulties for this technique. We present a novel approach, integrating principal component analysis (PCA) and supervised affinity propagation clustering (SAPC). In this method, fMRI data are initially processed by PCA to obtain a preliminary image of brain activation. SAPC is then used to detect different brain functional activation patterns. We used a supervised Silhouette index to optimize clustering quality and automatically search for the optimal parameter p in SAPC, so that the basic affinity propagation clustering is improved by applying SAPC. Four simulation studies and tests with three in vivo fMRI datasets containing data from both block-design and event-related experiments revealed that functional brain activation was effectively detected and different response patterns were distinguished using our integrated method. In addition, the improved SAPC method was superior to the k-centers clustering and hierarchical clustering methods in both block-design and event-related fMRI data, as measured by the average squared error. These results suggest that our proposed novel integrated approach will be useful for detecting brain functional activation in both block-design and event-related experimental fMRI data. [ABSTRACT FROM PUBLISHER]