ISSN 0253-2778

CN 34-1054/N

2013 Vol. 43, No. 8

Display Method:
The wide-diameter of regular graphs
LI Jiaao, XU Junming
2013, 43(8): 603-606. doi: 10.3969/j.issn.0253-2778.2013.08.001
The diameter with width m of a graph G is defined as the minimum integer d for which between any two distinct vertices in G there exist at least m internally disjoint paths of length of at most d. It was shown that the tight upper bound on m-diameter of w-regular w-connected graph with order n is(n-2)(w-2)[](w-m+1)(3m-w-4)+1 for any integer m with 2w+5[]3≤m≤w. Some known results can be deduced or improved from the obtained result.
Joint semiparametric mean-covariance modeling by moving average Cholesky decomposition for longitudinal data
XING Xin, LIU Meimei, ZHANG Weiping
2013, 43(8): 607-621. doi: 10.3969/j.issn.0253-2778.2013.08.002
Modeling the mean and covariance simultaneously has recently received considerable attention when efficiently analyzing the longitudinal data. An unconstrained and statistically interpretable reparameterization of covariance matrix itself was presented by utilizing a novel Cholesky factor. The entries in such decomposition have moving average and log innovation interpretation and can thus be modeled as functions of covariates. With this decomposition and the consideration of model flexibility, new semiparametric models for jointly modeling the mean and covariance itself were proposed, rather than its inverse as commonly studied in literature. A spline based approach using generalized estimating equations was developed to estimate the parameters in the mean and the covariance. It was shown that the estimators for the parametric parts in both the mean and covariance are consistent and asymptotically normally distributed, and the nonparametric parts could be estimated at an optimal rate of convergence. Simulation studies and real data analysis illustrate that the proposed approach could yield highly reliable estimation of the mean and covariance matrix.
Quasi-cyclic codes over Zps
CHU Qiang, ZHU Shixin
2013, 43(8): 622-625. doi: 10.3969/j.issn.0253-2778.2013.08.003
The quasi-cyclic codes of length mn over R=Zps were studied, where p is a prime and s is an arbitrary positive integer. By exploring the structure, the quasi-cyclic codes of length mn over R were shown to be equivalent to A-submodules of An, where A=R[x]/(xm-1). Then the case was studied in which quasi-cyclic codes over R can be decomposed into a direct sum of a fixed number of irreducible cyclic submodules when gcd(m,p)=1.
Improvements for direct sampling stochastic simulation and GPU implementation
XIE Qing, PENG Wei, LIU Yaoge, HUANG Tao, LU Detang
2013, 43(8): 626-630. doi: 10.3969/j.issn.0253-2778.2013.08.004
The direct sampling stochastic simulation method for reservoir modeling was discussed, the selection of geological pattern component was improved, and a method was presented which combined the structural characteristic information of the spatial relationship with the pattern component. CUDA (compute unified device architecture)-based parallel strategies were also proposed for obtaining an optimal solution within the pattern subspaces. Experimental results show that the proposition of the pattern component selection greatly improves the large-scale continuity of the sand channels in the two-facies sedimentary system. Further, the parallel computing method for solving the pattern subspace has small time complexity. The parallel computational efficiency on GPU shows a 10X to 100X improvement compared with the serial implementation with different computing parameters.
Zinc accumulation in paddy rice (Oryza stavia L.) by agronomic biofortification through soil-applied zinc fertilizers
ZHAO Li, WANG Zhangmin, HUANG Yang, YUAN Linxi, YIN Xuebin
2013, 43(8): 631-638. doi: 10.3969/j.issn.0253-2778.2013.08.005
A field experiment was designed to explore zinc (Zn) accumulation characteristics in mature paddy rice plants (Japonica rice Yang Yu No.2) after agronomic Zn biofortification. Zn fertilizers were distributed to the paddy field during the tillering and filling stages. Rice plants were harvested and analyzed in the mature stage. The results show that Zn contents in all organs and Zn accumulation per plant increase with the increasing level of fertilization, while Zn distribution vary with different treatments. The highest Zn content in stems is up to (1349±209)mg·kg-1, which is 43 times that of the control group (tillering stage), while Zn contents in brown rice increase by not more than 209% and 297% for the tillering and filling stage treatments, respectively. Zn accumulation in the tillering stage treatment is significantly higher than that in the filling stage (the maximum accumulation is 4540 μg for the tillering stage and 2662 μg for the filling stage). In contrast, Zn harvest index is up to 0336 for the filling stage, much higher than that of the tillering stage with a maximum of 0194. Zn biofortification through soil-applied Zn fertilizers can not only significantly increase Zn accumulation of the rice plants but also increase Zn content and Zn mass in grains. Compared to the tillering stage, it is more conducive to improve Zn level in rice grains during the filling stage.
A fusion method for TH-1 images based on fast discrete curvelet transforms
ZHU Qian, LI Xia
2013, 43(8): 639-644. doi: 10.3969/j.issn.0253-2778.2013.08.006
As some TH-1 images have the problem of big noise, a fusion method for TH-1 images based on FDCT was proposed. During the fusion processing, the sub-band of low frequency was processed by the weighted average algorithm; the sub-band of middle frequency, which has lower noise, was processed by the biggest region edge detection algorithm; the sub-band of the highest frequency, which has more intensive noise, was processed by the maximum substitution algorithm. The proposed method clearly outperforms traditional fusion methods in common image evaluation indicators and noise reduction evaluation indicators.
Fabrication of nanoporous copper oxide film biosensor with a polymer sphere template and its application to glucose sensing
LIU Hao, QIAN Cheng, XU Haihong, WU Shouguo
2013, 43(8): 645-653. doi: 10.3969/j.issn.0253-2778.2013.08.007
A nanoporous CuO film biosensor was fabricated on a Cu substrate electrode by the colloidal-crystal polystyrene template technique with the help of potentiostatic plating and potential cyclic scanning. The direct electrocatalytic oxidation of glucose in alkaline medium on nanoparticle CuO film modified electrode has been investigated in detail. When applied to detect glucose, the sensor exhibited a linear response of up to 32 mmol/L of glucose, and a high sensitivity of 3 799 μA·mM-1·cm-2, higher than that of most nonenzymatic glucose sensors reported in the literature. The sensor response time was less than 3 s and the detection limit was 037 μmol/L (at signal/noise=3). This improvement is due to the nanoporous structure and the greatly enhanced effective surface area. In addition, the sensor also performed well for measuring glucose concentrations in human blood serum samples. The results indicate that the nanoporous CuO film modified electrode allows highly sensitive and selective, stable, and fast amperometric sensing of glucose and is thus promising for the further application in nonenzymatic glucose sensors development.
Photodegradation of sulfa antibiotics and the impact of fulvic acids on it in water
SUN Xingxia, XU Yu
2013, 43(8): 654-660. doi: 10.3969/j.issn.0253-2778.2013.08.008
Sulfa antibiotics are widespread antimicrobial agents in aquatic environments, and their primary degradation pathway is photodegradation. Through the research on the photochemical kinetics of sulfamethazine (SAD) and sulfamethoxazole (SMZ), the self-sensitized photodegradation of two sulfa antibiotics in pure water and the effects of aqueous dissolved organic matter fulvic acids (FA) on photodegradation were investigated. In pure water, the photodegradation of the two sulfa antibiotics follows pseudo-first-order kinetics, but with different mechanisms. In addition, the photodegradation of the sulfa antibiotics are significantly influenced by the concentration of aqueous fulvic acids. For sulfamethazine, high concentrations of FA (20, 50, 100 mg/L) are favorable for the photodegradation of SAD while low concentrations of FA (2 mg/L) would inhibit the photodegradation. For sulfamethoxazole, the presence of low concentration of FA (02, 2 mg/L) slightly accelerates the degradation, whereas high concentrations of FA (20, 50, 100 mg/L) decrease the degradation rate of the compound.
Stripping analysis of trace cadmium and lead in edible salts by using the over-oxidized poly-(N-acetylaniline) modified electrode with in-situ deposited bismuth film
WANG Xuemei, WU Shouguo, ZHOU Lei, LIU Hao, ZHANG Zhixin
2013, 43(8): 661-670. doi: 10.3969/j.issn.0253-2778.2013.08.009
The over-oxidized poly-(N-acetylaniline) modified glassy carbon electrode with in-situ deposited bismuth film (Bi/over-oxidized PNAANI/GCE) was employed for simultaneous determination of trace Cd(Ⅱ) and Pb(Ⅱ) in edible salts with square wave anodic stripping voltammetry. Such an over-oxidized PNAANI film possesses excellent cation permselectivity, and can remarkably increase the sensitivity and selectivity of the modified electrode. The in-situ deposited bismuth film was used as an alternative to mercury to improve the preconcentration ability for Cd(Ⅱ) and Pb(Ⅱ). The calibration curves for Cd(Ⅱ) and Pb(Ⅱ) both covered two linear ranges, 0.2~3.0 μg·L-1 and 3.0~33 μg·L-1. The detection limits of Cd(Ⅱ) and Pb(Ⅱ) were 0.015 μg·L-1 and 0.029 μg·L-1 respectively with a deposition time of 300 s. Moreover, this as-prepared electrode has high stability and anti-interference capability. The proposed method was successfully applied to the determination of cadmium and lead in edible salt samples.
Large eddy simulation of vortex breakdown bubble in the unconfined non-reactive swirling flow
ZHANG Jimin, HAN Chao, YE Taohong
2013, 43(8): 671-678. doi: 10.3969/j.issn.0253-2778.2013.08.010
Large eddy simulation (LES) was applied to the non-reactive cases with medium swirl numbers (N29S054 and N29S045) of the Sydney swirl burner, and the instability mode of the vortex breakdown bubble (the downstream second recirculation zone) was investigated. The statistical moment obtained from LES results shows good overall agreement with experimental data. The vortex breakdown bubble (VBB) did not exhibit the spiral-type, and was not surrounded by the spiral precessing vortex core (PVC), which indicates that the VBB shows no distinct precession motion. The instantaneous velocity contours suggest the existence of cyclic collapse/contraction and expansion of VBB. The distinct peak of power spectrum density gives further evidence for periodic motion.
Fractal structure characteristic of the diffusion flame of moving fire on linear motion
LOU Bo, XU Jianhong, LIN Zhenguan, XU Yi
2013, 43(8): 679-686. doi: 10.3969/j.issn.0253-2778.2013.08.011
Image series of a moving fire on linear motion were acquired by a high-speed video camera. Applying image processing technology and the fractal theory, the fractal structure characteristic of the diffusion flame of moving fires was studied. The results revealed that the diffusion flame of moving fires possesses fractal dimension characteristics and it increases with the velocity in the same acceleration. When the velocity of a moving fire reaches a certain value, the fractal dimension of the diffusion flame increases within a small range; under the condition of a large acceleration and velocity, its fractal dimension increase rapidly with the velocity, and can influence the wrinkle and distortion. There are certain differences between a moving fire and a static fire, which can be identified by comparing the fractal dimensions of them.