This paper mainly studies the SK1 and relative SK1 group of the integral group ring of Z[C2k×C2n]. A lower bound of 2-rank of K2(Z[C2k×C2n]) is given, therefore a lower bound for the order of K2(Z[C2k×C2n]) is established.
We characterize the sufficient and necessary conditions with respect to α and β which make the Hardy operator Hn and the Hardy operator's conjugate operator Hn* be bounded from L|x|α1(Rn) to L|x|βq( R n) with 1≤q<∞ in n-dimensional Euclidean spaces, respectively.
In this article, we study the change point problem with generalized Lambda distribution based on information criterion. It was previously pointed out that, to make the conclusion more statistically convincing, the significant level α and its associated critical value cα could be introduced. We prove that, under ordinary conditions, this kind of information criterion is equivalent to the maximum likelihood ratio test in asymptotic formation. The simulation study is carried out with five different information criterions and the method is applied to treat practical data. The results show the validity of this method.
Three-dimensional simulation on conjugate heat transfer in fluid-structure coupled field is carried out. The calculation model is built for the dual-cooled lithium-lead blanket, which is the key technology of international thermonuclear experimental reactor. The effects of thermal conductivity of FCI material SiC and the convection heat transfer coefficient on temperature field are analyzed. The results show that temperature gradients and thermal stresses decrease when the material has good thermal conductivity. High convection heat transfer coefficient results in lower temperature and decrease in thermal deformation.
We study the heat transfer performance of the railway switches and establish a calculation model for minimum heating power at different snow melting positions under different environment conditions. The calculation model provides the reliable theory for the engineering applications of electric heating snow-melting system.
An investigation of soil fauna was carried out in Ligusticum chuanxiong Hort plantation. The average density of soil fauna was 3.13×104 ind/m2, belonging to 3 phyla, 8 classes, and 16 orders. The density of soil fauna and group numbers in Ligusticum chuanxiong Hort field was lower than that in vegetable filed. The densities of omnivorous and saprozoic soil fauna in vegetable filed were significantly higher than those in Ligusticum chuanxiong Hort field(P<0.05), but the densities of the predators and phytophaga were lower(P<0.05). The values of DG and C indexes in vegetable filed were higher than those in Ligusticum chuanxiong Hort field, but the values of J and H' were lower.
Daily PM2.5 samples were collected in Chengdu for a period of one month in each of the seasons of 2011. Particle scattering coefficient and particle absorption coefficient were synchronously measured. The seasonal and daily variations in bsp and bap and the relation between bext (bsp+bap) and the PM2.5 mass concentration was discussed based on above-measured data to investigate the causes of hazy weather. The results show that the annual bsp and bap values were (456±237) Mm-1 and (96±73) Mm-1, respectively, and that daily variation in bsp was influenced by metoroligical factors and transpotation of polltants from Chengdu suburban while daily variation in bap was influenced by metoroligical factors and local motor emission in the urban aera. Good correlation between PM2.5 and bext was found (R2>0.92), which suggests that the higher PM2.5 concentration is the key impact factor for hazy weather.
The hexavalent chromium transport in groundwater in Jiaozuo part of the middle route of south to north water transfer project was investigated by using the numerical simulation technology. The simulation results show that hexavalent chromium contamination plume may migrate to the area beneath the main canal about 20 years later, which will place a threat to the security of water quality of the main canal. Furthermore, the primary factors controlling the hexavalent chromium transport in groundwater were identified for different simulation periods. The investigation results may have implication on protection of water quality of the main canal.
Based on HJ-CCD remote image data, object-oriented technology was applied into the land-cover extraction in Hunan Province. We mainly focus on land-cover survey method using HJA/B remote sensing images on large scale and explore a set of approaches to get land-cover information using object-oriented technology. The overall accuracy of the results is 84.99% and Kappa coefficient is 82.79%. The research results show that land-cover survey method using HJ-CCD remote sensing images and object-oriented classification technology is feasible and effective on large scale.
In order to improve China land assessment model, exposure assessment, toxicological assessment, and risk characterization methods of CLEA (contaminated land exposure assessment) model are introduced. Generic assessment criteria mode is used to assess risks of 13 pollutants in a demonstration area in China, and the assessment results are analyzed. It is suggested that the concept of background exposure for threshold effects in the CLEA model may be used to improve China land use risk assessment model.
It is theoretically feasible that transmission seismic layer computer tomography technique can be used to detect the small faults and collapse columns in the mining working face. Three indoor physical simulations verify that the transmission seismic layer computer tomography technique has a strong response to the interface where media has apparent difference (responding sensitively to the small faults and the high-speed anomalous bodies in the simulated coal seam). Therefore, this technology can be effectively used in the detection of small faults and high-speed karsts collapse columns in the mining working face. The present work provides support for its practical application in the mine.
In this paper, a fast ship detection method based on ScanSAR image is presented. Firstly, the influence of scalloping noise on ship detection is reduced by seasonal local brightness transform. Secondly, an improved two-parameter CFAR ship detection based on OpenMP before ScanSAR images mosaicking is adopted, and it not only avoids the influence of splicing apertures on ship detection but also reduces the time of ship detection greatly. At last, the final detection targets are derived from mosaicking ScanSAR images. Experimental results on 15 different ScanSAR images show that the proposed system has good detection performance and prominent timeliness.
We improved the forensic automatic speaker recognition(FASR) system based on GMM by applying the reference database to reduce the demands of suspect's recording quantity. We established an improved FASR system based on GMM-UBM, in which a small background population is used. The proposed system was tested in the database of fixed telephone channel and mobile channel, respectively.
In order to construct gene regulatory network, we propose a non-stationary dynamic Bayesian networks method that systematically integrates expression data with multiple sources of prior knowledge. Our method is based on Gaussian mixture Bayesian network model, change point process, and separate energy function of prior knowledge. Using an reversible jump Markov chain Monte Carlo sampling algorithm, we divide data into disjunct compartments, infer network structures, and measure the influence of the respective prior knowledge. Finally, we apply our approach to treat both synthetic data and biological data. The results show that the proposed method improves the network reconstruction accuracy.
Serial motion estimation does not satisfy real-time requirements of video coding in mobile terminal. A divided-spiral-path parallel motion estimation based on normalized partial distortion search is proposed to make full use of multi-core computing power, and it retains low computational complexity of the serial algorithm. Experimental results show that the proposed algorithm achieves speedup ratios of 3.88-3.96 on a 4-core CPU platform while the cost of trivial computational effort increases by less than 1.2%.
An active contour model, which combines LGDF model and CV model and uses the image entropy, is proposed to solve the problem of sensitivity to the initial contour of the original active contour. First the level set force is defined by a linear combination of the LGDF and CV models incorporating image entropy. Then the weights of the forces are regulated by the local image information. Experiments on blood X-images, noise images, and SAR image show that the proposed method is robust to initialization and less sensitive to noises.
A new signal presence detection method of MPSK signal, suitable for LEO burst communications, is proposed. The new method uses E[(I2+Q2)2] as the detection quantity, and it has simple digital structure and is convenient for onboard implementation. The theoretical derivation, simulation validation, and analysis for this method are presented. In the specific applications, the performances of detection probability and false-alarm probability are simulated.
Aiming at the problem that radar echoes from some airborne targets contain modulation sections and airframe sections, we derive the parameter models for the spectrum characteristics of the modulation section from the rotating parts and its echo amplitude on basis of analysis of the echo mathematical model of the rotating parts, indicate the application conditions of some previous models in the literature, and analyze the observation conditions of the modulation effect as well as the influence on the modulation characteristics induced by partial blades sheltering. Simulation is performed in different parameter conditions, and the results show that the above-mentioned theoretical analysis and the modulation characteristic parameter models are reliable and effective.
Though some algorithms were proposed to predict the traffic distribution in mobile communication networks automatically, they are not suitable for large-scale calculation and application in current mobile communication networks. Considering the characters of mobile communication networks, we present an optimization model for precise traffic distribution prediction based on the optimization theory. Moreover, a practical algorithm is derived in order to realize the optimization model by computer. It aims to identify the most possible position of the traffic by matching the NCS data with the field strength prediction results. The experimental results show that the algorithm is practical and efficient.
The phosphate rock was activated in a hydrothermal reaction kettle by using ammonium sulphate as activator, and the hydrothermal technological conditions were studied. The results showed that the effect of activation was strong when the water-solid ratio was 1:1; ammonium sulphate-phosphate rock ratio was 3:7; hydrothermal time was 12 h; and hydrothermal temperature was 220℃. The available P content in activated phosphate rock increased by 78.2%. The phase change of activation products was studied by X-Ray diffraction, and the phase was changed under the treatment of hydrothermal activation.