Abell团角分布的二级矩,三级矩以及空间三点相关函数

本文用"胞内计数"方法对北天区的富度R≥1的Abell团角分布的二级矩和三级矩作了统计,并由此得到了Abell团的空间三点相关函数;同时,本文还对D≤4,R≥1的Abell团红移样品的三点相关函数进行了统计.这些统计分析得到的结果与通过估计红移值对四组子样品进行统计分析所得到的结果是一致的,从而进一步说明,星系和Abell团的三点相关函数可用同一个普遍的标度形式来描述.

Waveguide Optimization for a 9.0μm GaAs-Based Quantum Cascade Laser

Improved waveguide designs for 9.0μm GaAs-based quantum cascade laser （QCL） structures are presented. Modal losses and confinement factors are calculated for TM modes with the transfer matrix method （TMM） and effective index method （EIM）. The thicknesses of the cladding layer and waveguide layer, the ridge-width, and the cavity length are all taken into account. Appropriate thicknesses of epilayers are given with lower threshold gain and more economical material growth time.

The σ-duals of Sequence Spaces

In this paper, the σ_duals of two classes important sequence spaces l 1(X) and l ∞(X) are investigated, and shows that some topology properties of locally convex space (X,τ) can be characterized by the σ _duals. The criterions of bounded sets in l 1(X) and l ∞(X ) with respect to the weak topologies generated by the σ _duals are obtained. Furthermore, a Schur type result and an automatic continuity theorem of matrix transformation are established.

A Solvable Decorated Ising Lattice Model

A decorated lattice is suggested and the Ising model on it with three kinds of interactions K1, K2, and K3 is studied. Using an equivalent transformation, the square decorated Ising lattice is transformed into a regular square Ising lattice with nearest-neighbor, next-nearest-nelghbor, and four-spin interactions, and the critical fixed point is found at K1 = 0.5769, K2= -0.0671, and K3 = 0.3428, which determines the critical temperature of the system. It is also found that this system and the regular square Ising lattice, and the eight-vertex model belong to the same universality class.

Three-dimensional analysis of a thick FGM rectangular plate in thermal environment

The thermal behavior of a thick transversely isotropic FGM rectangular plate was investigated within the scope of three-dimensional elasticity. Noticing many FGMs may have temperature-dependent properties, the material constants were further considered as functions of temperature. A solution method based on state-space formulations with a laminate approximate model was proposed. For a thin plate, the method was clarified by comparison with the thin plate theory. The influences of material inhomogeneity and temperature-dependent characteristics were finally discussed through numerical examples.

A practical and dynamic key management scheme for a user hierarchy

In this paper, we propose a practical and dynamic key management scheme based on the Rabin public key system and a set of matrices with canonical matrix multiplication to solve the access control problem in an arbitrary partially ordered user hierarchy. The advantage is in ensuring that the security class in the higher level can derive any of its successor’s secret keys directly and efficiently and show it is dynamic while a new security class is added into or a class is removed from the hierarchy. Even the ex-member problem can be solved efficiently. Moreover, any user can freely change its own key for some security reasons.

The Influence of Edge Restraining Stiffness on the Transverse Vibrations of Rectangular Plate Structures

This paper presents an analytical study on the influence of edge restraining stiffness on the transverse vibrations of rectangular plate structure. An improved Fourier series method was employed to analyze the transverse vibration of plate structure with general elastically restrained boundary conditions. A linear combination of a double Fourier series and eight auxiliary terms was sought as the admissible function of the flexural displacement of the plate, each term being a combination of a polynomial function and a single cosine series expansion. The auxiliary terms were introduced to ensure and improve the smoothness of the original displacement function and its derivatives at the boundaries. Several numerical examples were given to demonstrate the validity and accuracy of the current solution. The influences of translational and rotational stiffness on the natural frequencies and mode shapes of plate were analyzed by numerical results. The results show that the translational stiffness has bigger influence on the natural frequencies than the rotational stiffness. It is generally well known that little change of the rotational stiffness has little influence on the mode shapes of plate. However, the current work shows that a very little change of rotational stiffness value may lead to a large change of the mode shapes of a square plate structure.

Stability analysis of linear multistep methods for neutral delay differential equations

The stability analysis of linear multistep (LM) methods is carried out under Kreiss resolvent condition when they are applied to neutral delay differential equations of the form y′(t)=ay(t)+by(t-τ)+ cy′(t- τ) y(t)=g(t) -τ≤t≤0 with τ>0 and a, b and c∈, and it is proved that the ‖B n‖ is suitably bounded, where B is the companion matrix.

New Poisson Sum Formula Derived by Squeezing Transformation in Quantum Optics

Using squeezing transform in the context of quantum optics and based on the Fourier series expansion we rigorously derive a new Poisson sum formula. Application of this new formula to the representation transformation of kq-wave function for describing electrons in periodic lattice is demonstrated. In so doing, the transition matrix element of harmonic oscillator in kq representation is derived.

Optimization of rotor shape for constant torque improvement and radial magnetic force minimization

The design of notch and barrier was optimized in order to improve the characteristics of constant torque while minimizing the cogging torque that occurs as a result of teeth and slot structure. The barrier was installed in order to minimize the cogging torque and torque ripple by finite element method (FEM) with a reduced barrier width toward the center of magnetic pole. The position and width of notch, which can offset cogging torque, can be calculated with energy distribution of air-gap using Fourier series. The optimized model demonstrates a 60% decrease in the cogging torque, a 75.3% decrease in the torque ripple and a 3% increase in the operating torque when compared with the basic model.

Investigation of the Mechanical Behavior of a Thin Composite Stiffened Skin with a Combined Joint

Many joint models available to predict secondary bending moments in the structure have a stiffness mismatch, while this type of structure widely used in aircraft. To determine how to represent a structure with a stiffness mismatch in a combined joint （bonded/riveted）, a non-linear finite element analysis was performed. The detailed validation of this analysis identified the composite stiffened skin as the most suitable model in three dimensions. The use of this model for validating the secondary bending moment to calculate the behavior of the stiffener edge is straightforward and reliable. Experiments were performed to determine the distribution of the load in a combined joint under a tensile load that creates a secondary bending moment in a structure with a stiffness mismatch. The influence of related joint design considerations on the load transferred by the joint were examined through a finite element parameter analysis. The results are compared to determine best approach to predict the mechanical behavior at the edge of the stiffener. A close agreement between the finite element analysis and experimental results was obtained. Test observations using a C-scan compared well with the predictions of the onset of crack growth.

A Hierarchical-Equation-of-Motion Based Semiclassical Approach to Quantum Dissipation

We present a semiclassical （SC） approach for quantum dissipative dynamics, constructed on basis of the hierarchical-equation-of-motion （HEOM） formalism. The dynamical components considered in the developed SC-HEOM are wavepackets＇ phase-space moments of not only the primary reduced system density operator but also the auxiliary density operators （ADOs） of HEOM. It is a highly numerically efficient method, meanwhile taking into account the high-order effcts of system-bath couplings. The SC-HEOM methodology is exemplified in this work on the hierarchical quantum master equation [J. Chem. Phys. 131, 214111 （2009）] and numerically demonstrated on linear spectra of anharmonic oscillators.

Spin Cut-off Parameter of Nuclear Level Density and Effective Moment of Inertia

The spin cut-off parameter of the nuclear level density and effective moment of inertia for a large number of nuclei have been determined from analysis of the experimental data on S-wave neutron resonances and spins of lowlying levels. Contrary to claims made before, it is shown the spin cut-off parameter differs considerably from their corresponding rigid body values, and the energy dependence of the effective moment of inertia confirms the interacting fermion model prediction.

DARPA Robotics Grand Challenge Participation and Ski-Type Gait for Rough-Terrain Walking

In this paper, we briefly introduce the history of the Defense Advanced Research Projects Agency(DARPA) Grand Challenge programs with particular focus on the 2012 Robotics Challenge. As members of team DRC-HUBO, we propose different approaches for the Rough-Terrain task, such as enlarged foot pedals and a transformation into quadruped walking. We also introduce a new gait for humanoid robot locomotion to improve stability performance, called the Ski-Type gait. We analyze the stability performance of this gait and use the stability margin to choose between two candidate step sequences, Crawl-1 and Crawl-2. Next, we perform a force/torque analysis for the redundant closedchain system in the Ski-Type gait, and determine the joint torques by minimizing the total energy consumption. Based on the stability and force/torque analysis, we design a cane length to support a feasible and stable Crawl-2 gait on the HUBO2 humanoid robot platform. Finally, we compare our experimental results with biped walking to validate the SkiType gait. We also present our team performance in the trials of the Robotics Challenge.

Performance Analysis of Parallel Eigensolvers of Two Libraries on BlueGene/P

Many applications in computational science and engineering require the computation of eigenvalues and vectors of dense symmetric or Hermitian matrices. For example, in DFT （density functional theory） calculations on modern supercomputers 10% to 30% of the eigenvalues and eigenvectors of huge dense matrices have to be calculated. Therefore, performance and parallel scaling of the used eigensolvers is of upmost interest. In this article different routines of the linear algebra packages ScaLAPACK and Elemental for parallel solution of the symmetric eigenvalue problem are compared concerning their performance on the BlueGene/P supercomputer. Parameters for performance optimization are adjusted for the different data distribution methods used in the two libraries. It is found that for all test cases the new library Elemental which uses a two-dimensional element by element distribution of the matrices to the processors shows better performance than the old ScaLAPACK library which uses a block-cyclic distribution.

A Survey of Various Refinements and Generalizations of Hilbert's Inequalities

Expounded in this survey article is a series of refinements and generalizations of Hilbert's inequalities mostly published during the years 1990 through 2002.Those inequalities concerned may be classified into several types (discrete and integral etc.), and various related results obtained respectively by L. C. Hsu, M. Z. Gao, B. C. Yang, J. C. Kuang, Hu Ke and H. Hong et.al are described a little more precisely. Moreover, earlier and recent extensions of Hilbert-type inequalities are also stated for reference. And the new trend and the research ways are also brought forward.

UNCONDITIONAL CAUCHY SERIES AND UNIFORM CONVERGENCE ON MATRICES

The authors obtain new characterizations of unconditional Cauchy series in terms of separation properties of subfamilies of p(N), and a generalization of the Orlicz-Pettis Theorem is also obtained. New results on the uniform convergence on matrices and a new version of the Hahn-Schur summation theorem are proved. For matrices whose rows define unconditional Cauchy series, a better sufficient condition for the basic Matrix Theorem of Antosik and Swartz, new necessary conditions and a new proof of that theorem are given.

Fast Algorithm for Maneuvering Target Detection in SAR Imagery Based on Gridding and Fusion of Texture Features

Designing detection algorithms with high efficiency for Synthetic Aperture Radar(SAR) imagery is essential for the operator SAR Automatic Target Recognition(ATR) system.This work abandons the detection strategy of visiting every pixel in SAR imagery as done in many traditional detection algorithms,and introduces the gridding and fusion idea of different texture fea-tures to realize fast target detection.It first grids the original SAR imagery,yielding a set of grids to be classified into clutter grids and target grids,and then calculates the texture features in each grid.By fusing the calculation results,the target grids containing potential maneuvering targets are determined.The dual threshold segmentation technique is imposed on target grids to obtain the regions of interest.The fused texture features,including local statistics features and Gray-Level Co-occurrence Matrix(GLCM),are investigated.The efficiency and superiority of our proposed algorithm were tested and verified by comparing with existing fast de-tection algorithms using real SAR data.The results obtained from the experiments indicate the promising practical application val-ue of our study.

Optical fiber sensor by cascading long period fiber grating with FBG for double parameters measurement

An optical fiber sensor for strain and temperature measurement based on long period fiber grating(LPFG) cascaded with fiber Bragg grating(FBG) structure has been proposed and realized both theoretically and experimentally. Theoretical analysis shows that two microstructures with similar sensitivities cannot be used for double parameters measurement. The LPFG is micromachined by the CO_2 laser, and the FBG is micromachined by the excimer laser. For the validation and comparison, two FBGs and one LPFG are cascaded with three transmission valleys, namely FBG1 valley at 1 536.3 nm, LPFG valley at 1 551.2 nm, and FBG2 valley at 1 577.3 nm. The temperature and strain characteristics of the proposed sensor are measured at 45—70 °C and 250—500 με, respectively. The sensitivity matrix is determined by analyzing wavelength shifts and parameter response characterization of three different dips. The proposed optical fiber sensor based on LPFG cascaded with FBG structure can be efficiently used for double parameters measurement with promising application prospect and great research reference value.