ISSN 0253-2778

CN 34-1054/N

2015 Vol. 45, No. 9

Display Method:
Original Paper
An approach to estimating nonlinear sufficient dimension reduction subspace for censored survival data
CUI Wenquan, WU Chenglong
2015, 45(9): 709-716. doi: 10.3969/j.issn.0253-2778.2015.09.001
An approach was proposed to estimating the nonlinear sufficient dimension reduction (SDR) subspace for survival data with censorship. Based on the theory of reproducing kernel Hilbert spaces (RKHS) and the double slicing procedure,the joint nonlinear sufficient dimension reduction central subspace was estimated by means of the generalized eigen-decomposition equation. And the weight function was estimated by the definition and property of SDR central subspace. The efficiency was improved by the iteration method while the algorithm was being implemented. Finally, the performance of the proposed method was illustrated on simulated data.
Gradient estimates for f-exponentially harmonic functions on complete Riemannian manifolds
2015, 45(9): 717-720. doi: 10.3969/j.issn.0253-2778.2015.09.002
For smooth metric measure spaces (M,g,e-fdvol), the gradient estimates of positive solutions to the f-exponentially harmonic functions was considered by using the maximum principle. Then a Liouville type theorem was obtained when the Bakry-Emery Ricci tensor was nonnegtive and the sectional curvature was bounded by a negative constant. This generalizes a result in Ref.[Wu J, Ruan Q, Yang Y H. Gradient estimates for exponentially harmonic functions on complete Riemannian manifolds. Manuscripta Mathematica, 2014, 143(3-4): 483-489], which is covered in the case where f is a constant.
Numerical simulation between long and short waves by multisymplectic method
WANG Lan, DUAN Yali, KONG Linghua
2015, 45(9): 721-726. doi: 10.3969/j.issn.0253-2778.2015.09.003
The multisymplectic structure-preserving scheme for the Schrdinger-KdV equation was investigated. First the canonical formulation of the equation was discussed. Then, it was discretized by the multisymplectic integrator, such as a midpoint integrator. Numerical results were presented to illustrate the validity of the new scheme.
Rapid time decay of weak solutions to the generalized Hall-magneto-hydrodynamics equations
TAO Qunqun, ZHANG Fei, DONG Boqing
2015, 45(9): 727-732. doi: 10.3969/j.issn.0253-2778.2015.09.004
The rapid time decay for solutions to the generalized Hall-magneto-hydrodynamics equations was studied. By developing the classic Fourier splitting methods, the more rapid L2 decay rate of the weak solutions as (1+t)-74 was derived. The trick is mainly based on the even lower frequency effect of the nonlinear term.
Some new criteria on p-supersolubility of finite groups
LIU Aming, LI Baojun
2015, 45(9): 733-736. doi: 10.3969/j.issn.0253-2778.2015.09.005
A subgroup H of a group G is called n-embedded in G if there exists a normal subgroup T of G,such that HT=HG and H∩T≤HsG, where HsG is the maximum s-quasinormal subgroup of G contained in H. Here, some new criteria on p-supersolubility of finite groups are obtained by n-embedded property of some subgroups.
Stability analysis of SEIR model with general contact rate
MA Yanli, XU Wenxiong, ZHANG Zhonghua
2015, 45(9): 737-744. doi: 10.3969/j.issn.0253-2778.2015.09.006
A type of SEIR epidemic model with different general contact rates β1(N), β2(N) and β3(N), having infective force in all the latent, infected and immune periods, was studied. And the threshold, basic reproductive number R0 which determines whether a disease is extinct or not, was obtained. By using the Liapunov function method, it was proved that the disease-free equilibrium E0 is globally asymptotically stable and the disease eventually goes away if R0<1. It was also proved that in the case where R0>1, E0 is unstable and the unique endemic equilibrium E* is locally asymptotically stable by Hurwitz criterion theory. It is shown that when disease-induced death rate and elimination rate are zero, the unique endemic equilibrium E* is globally asymptotically stable and the disease persists.
Research and application of beam auto-modeling method for three-dimensional conformal radiation therapy treatment planning system
LI Jia, ZHU Qinjun, LIU Songlin, CHEN Zhi
2015, 45(9): 745-750. doi: 10.3969/j.issn.0253-2778.2015.09.007
To insure the accuracy of irradiation, the three-dimensional conformal radiation therapy (3DCRT) treatment planning system (TPS) should, based on the types and orientations of the beam, automatically calculate the source position and the field size of the irradiation beam to cover the target (tumor) volume while avoiding excessive irradiation of the surrounding tissues. A beam modeling method was developed: first, based on the derived matrix of coordinate system transformation, the 3D patient model is tranfered from the patient coordinate system to the beam coordinate system; then, the iso-center coordinate of the target is caculated, from which the coordinate of the beam source is derived; finally, the target volume is projected onto the iso-center plane to identify the field size of the irradiation beam. By implementing of this method, the beam modeling module was developed with features of 3D visualization and a friendly user interface. The accuracy and efficiency of this module was verified based on the benchmark cases of the AAPM report 55 and the clinical patient image data by testing and comparing it with the beam modeling module of a commercial 3DCRT TPS.
Corrosion behavior of 316L and T91 steels in stagnant lead-bismuth eutectic at 550 ℃
TIAN Shujian, ZHANG Jianwu
2015, 45(9): 751-756. doi: 10.3969/j.issn.0253-2778.2015.09.008
Liquid lead-bismuth eutectic (LBE) is an important spallation target material and coolant candidate in accelerator driven sub-critical systems (ADS), and is also a key coolant material for advanced fast reactors. Since LBE has a strong corrosion for structural materials, its application is required to give priority to the problem of compatibility between LBE and structural materials at high temperatures. Experiments were conducted on the corrosion behavior of the two ADS candidate structural materials (316L and T91 stainless steels) in static LBE at 550 ℃ for 1000 h. The microstructure morphology of the etched cross-sections of the samples were characterized by scanning electron microscopy (SEM), and the distribution of the main chemical compositions in the interface of LBE and the matrix was analyzed by energy dispersive spectroscopy (EDS). The results showed that the two samples were subjected to a strong dissolution of the elements and the LBE penetration, and T91 showed a slightly better corrosion resistance to LBE than 316L.
Morphology of non-Euclidean disks
TIAN Zhongliang, LIANG Haiyi
2015, 45(9): 757-762. doi: 10.3969/j.issn.0253-2778.2015.09.009
The out-of-plane displacements of plates are influenced by factors such as nonuniform thermal expansion which corresponds the research of 3D deformation of elastomer controlled by the target metric in non-Euclidean plates. The well-known mass-spring model was used to simulate the deformation of disks driven by given swelling functions corresponding positive and negative target Gaussian curvature K. The evolution of waves under negative target Gaussian curvature was analyzed with different thickness t. The impact of swelling factor and strain gradient on the ratio of bending energy to strain energy was studied with the same thicknesses. The ratio transforms rapidly when the number of waves changes for K<0. Scaling of stretching and bending energy about thickness was obtained while dicks were driven by the same swelling function. Stretching and bending energy both vary like t2.5 with K>0, compared with t4 of bending energy in disks with K<0.
An analysis method for structural reliability sensitivity based on the bisection method of sampling
CHEN Pengfei, LIU Haifang, LIU Qiaoling
2015, 45(9): 763-769. doi: 10.3969/j.issn.0253-2778.2015.09.010
Targeting the problem of limit state equations being often implicit and demanding a great amount of computation, an analysis method was proposed for structural reliability sensitivity based on the bisection method of sampling. Combining with the most probable point method of structure reliability analysis and the bisection method of sampling, the proposed method first linearizes the state equations near the initial point based on Taylor expansion method and determines the optimal step-length based on gradient information; then, it locates the new sampling point by means of bisect sampling step-length of reliability index β; finally, by several iterations, it finds out the most probable point (MPP) that meet the accuracy requirement of the structures and system to calculate reliability and reliability sensitivity of influencing parameters according to the information of the sampled path. Examples of the computation and engineering were given. A comparison with existing methods for solving implicit structure reliability problems indicated that the proposed method possesses the advantages of reliable convergence and less sampling, making it especially suitable for performing reliability analyses of large-scale complicated implicit structures and systems.
Network information service management system for early auxiliary diagnosis and treatment of malignant tumors
2015, 45(9): 770-775. doi: 10.3969/j.issn.0253-2778.2015.09.011
Malignant tumors have become a major global cause of death, and their early diagnosis and detection can often prolong patients lives. An network information service management system for early auxiliary diagnosis and treatment of malignant tumors was presented. And it can offer the provision of early diagnosis as well as individualized and humanizing medical services to patients with malignant tumors via remote network management platforms. It is not only beneficial to clinicians in providing post-surgery treatments but also to the patients for a better understanding of their treatment after the discovery of their tumors. This can help them better cooperate with their doctors, strengthen their confidence in survival and thus help prolong their lives.
Knowledge reduction in intuitionistic fuzzy objective information systems
BAO Zhongkui, YANG Shanlin
2015, 45(9): 776-782. doi: 10.3969/j.issn.0253-2778.2015.09.012
The classical rough set theory can not be directly employed to reduce knowledge of intuitionistic fuzzy objective information systems. The dominance relation is introduced to intuitionistic fuzzy objective information systems, and intuitionistic fuzzy rough set model based on dominance relation was established. Then, based on the definition of distribution consistent set and assignment consistent set, the judgment theory and discernibility matrices for distribution reduction and assignment reduction were given, and knowledge reduction methods of intuitionistic fuzzy objective information systems were presented. Finally, an example was given to illustrate the effectiveness of the proposed method.
Effect of fireproof clogging on combustion resistent property of external thermal insulation systems with curtain walls
ZHANG Miao, SONG Wenhua, LIU Xingna, WEI Dong, HUANG Xin
2015, 45(9): 784-794. doi: 10.3969/j.issn.0253-2778.2015.09.013
The fire spreading on insulation systems with curtain walls under different fire prevention measures was simulated by FDS. Then the effectiveness of fire prevention measures was discussed and the design parameters of fire prevention structure were obtained. Finally, combustion performance on external insulation systems with curtain walls under different fire prevention measures were tested, their feasibility and effectiveness under real conditions were analyzed, and the optimal combination of fire prevention structure and its technical requirements were put forward.