一边支承三边自由矩形板振形曲线及其正交性

本文提出主振方向排序法的思想 ,建立了一边支承三边自由矩形板统一的振形函数表达式。该振形曲线基本符合板边界条件所限定的变形曲线形态 ,可以满足全部边界条件 ,又具有振形的正交性。本文阐明了主振方向排序法的物理含义 ,推导了 2种矩形板自由振动频率方程 ,计算了各 2 5个自振频率及相应的振形。

四边支承矩形板振形曲线及其正交性

主振方向排序法认为 ,板的振形曲线中振动波形在主振方向上是唯一的 ,在另一方向上是不唯一的 ,由此建立了四边支承矩形板精确的振形曲线表达式 .这种振形曲线可以满足振动微分方程和全部边界条件 ,还具有振形的正交性 .通过推导证明了振形正交性的存在 ,阐明了主振方向排序法的物理含义 。

一种提高SMS4安全性的算法

SMS4是在国内正式使用并于2006年公布的第一个用于无线局域网的商用分组密码算法。关于其安全性研究的公开论文很少,文中研究SMS4算法的安全性并提出了一个提高其安全性的算法,详细讨论了该算法的正形性以及密码运算操作的正确性,同时通过与SMS4原算法的理论分析以及实验数据对比,得出结论:本SMS4改进算法在保证加解密操作的正确性以及基本不改变算法应用领域的前提下,提高了原SMS4算法的安全性。

三边支承一边自由矩形板自由振动分析

板自由振动振形必须具有正交性,采用主振方向排序法建立三边支承一边自由矩形板振形函数表达式可以满足振动微分方程和全部边界条件,又具有振形的正交性.该振形曲线中的振动波形数在主振方向上是唯一的,在另一方向上是不唯一的,振形曲线形状符合板边界条件所能限定的变形形态.通过证明振形正交性的存在,分析振形函数表达式的结构形式,推导不同边界条件矩形板的频率方程,计算板的自振频率及相应振形,并与前人的结果进行了比较,从理论上说明了该方法的正确性.

SMS4算法的一种改进

"无线局域网产品使用的SMS4密码算法"是国内官方公布的第一个商用密码算法。本文简要介绍了SMS4密码算法的加解密原理,提出了一个对SMS4算法的改进方案,并详细对该改进方案进行了正形性以及加解密正确性的验证,同时对该方案的安全性以及资源占用情况与SMS4算法进行了对比分析。

Bonding properties of interface in Fe/Al clad tube prepared by explosive welding

A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes possessing good bonding interface have higher shear strength than that of pure aluminum and can bear both axial and radial deformation.The original interface between aluminum layer and ferrite layer was observed by scanning electron microscopy（SEM）.The results show that the clad tubes with good bonding properties possess the interface in wave and straight shape.The Fe/Al clad tube was used to manufacture the T-shape by hydro-bulging.It is found that the good-bonding interface of the Fe/Al clad tube plays a dominant role in the formation of the T-shape.

Bounds of Interpolation Error for Arbitrary Narrow Quadrilateral Quasi-Wilson Element

Based on the construction of reference e le ment and bilinear transformation, a quasi-Wilson element for arbitrary narrow q uadrilateral is presented. Using the interpolation Theorem for narrow quadrilate ral isoparametric finite element and related methods, the bounds of interpolatio n error for arbitrary narrow quadrilateral quasi-Wilson element are obtained in case when the condition ρ K/h K≥σ 0】0 is not satisfied, where h K is the diameter of the element K and ρ K is the diameter of an ins cribed circle in K. The interpolation error is O(h2 K) in the L2( K)-norm and O(h K) in the H1(K) -norm provided that the in terpolated function belongs to H2(K).

Viscoelastic model for asphalt mixture under repeated haversine load

The series-wound dashpot of the Burgers model is modified by introducing the strain hardening parameter, and the new model is considered as a combination of the modified dashpot and the Van Der Poel model. The cyclical pulse load consisting of a haversine load time and a rest period is adopted to simulate the actual vehicle load, and the permanent strain model under the repeated load is derived from the rheological and viscoelastic theories. Subsequently, the model is validated by the results of uniaxial repeated load permanent deformation tests of three asphalt mixtures. It is indicated that the proportion of residual viscoelastic strain to permanent strain decreases gradually with the load cycles, and only accounts for 2% to 3% during most of the loading period. If the rest period is long, the residual viscoelastic strain is little. The rest period of the actual vehicle load may be long enough, so the residual viscoelasticity can be ignored and the simplified model can be obtained. The proposed model can well describe the permanent deformation of asphalt mixtures under repeated load.

Several Results on the Number of Zeroes of Nonlinear Mappings on Bounded Regions

With homotopy methods, this paper discusses the existence and the number of zeroes of nonlinear mappings on bounded regions and extends some classical theorems.

Optimizing crashworthiness design of square honeycomb structure

To provide theoretical basis for square honeycombs used as crashworthy structures, energy-absorption properties of metal square honeycombs and the size optimization were performed. Specific energy absorption(SEA) was defined as the energy absorbed by the honeycomb structure per unit volume. This parameter was often used for determining the crashworthiness of thin-walled structures. In order to find the most optimized metal square honeycomb structure with the maximum SEA and the lowest peak stress, the cell length and the foil thickness of the metal honeycombs were optimized, with a low peak stress and a high SEA set as the two primary objectives. The pre-processing software Patran was used to build FE models, and the explicit solver LS-DYNA was employed to perform the crashworthiness analyses. The results show that the square honeycomb exhibits good energy absorption performance in some cases. The geometry is effective using 16.8% less buffer structure volume than the hexagonal honeycombs with a peak stress limitation of 1.21 MPa.

Advances in diagnosis,treatment and palliation of cholangiocarcinoma:1990-2009

Several advances in diagnosis,treatment and palliation of cholangiocarcinoma(CC)have occurred in the last decades.A multidisciplinary approach to this disease is therefore recommended.CC is a relatively rare tumor and the main risk factors are:chronic inflammation, genetic predisposition and congenital abnormalities of the biliary tree.While the incidence of intra-hepatic CC is increasing,the incidence of extra-hepatic CC is trending down.The only curative treatment for CC is surgical resection with negative margins.Liver transplantation has been proposed only for selected patients with hilar CC that cannot be resected who have no metastatic disease after a period of neoadjuvant chemo-radiation therapy.Magnetic resonance imaging/magnetic resonance cholangiopancreatography,positron emission tomography scan,endoscopic ultrasound and computed tomography scans are the most frequently used modalities for diagnosis and tumor staging.Adjuvant therapy,palliative chemotherapy and radiotherapy have been relatively ineffective for inoperable CC.For most of these patients biliary stenting provides effective palliation.Photodynamic therapy is an emerging palliative treatment that seems to provide pain relief,improve biliary patency and increase survival. The clinical utility of other emerging therapies such as transarterial chemoembolization,hepatic arterial chemoinfusion and high intensity intraductal ultrasound needs further study.

Hybrid Strategy of Particle Swarm Optimization and Simulated Annealing for Optimizing Orthomorphisms

Orthomorphism on F2^n is a kind of elementary pemmtation with good cryptographic properties. This paper proposes a hybrid strategy of Particle Swarm Optimization （PSO） and Sirrmlated Annealing （SA） for finding orthomorphisrm with good cryptographic properties. By experiment based on this strategy, we get some orthorrorphisrm on F2^n = 5, 6, 7, 9, 10） with good cryptographic properties in the open document for the first time, and the optirml orthorrrphism on F found in this paper also does better than the one proposed by Feng Dengguo et al. in stream cipher Loiss in difference uniformity, algebraic degree, algebraic irrarnity and corresponding pernmtation polynomial degree. The PSOSA hybrid strategy for optimizing orthomerphism in this paper makes design of orthorrorphisrm with good cryptographic properties automated, efficient and convenient, which proposes a new approach to design orthornorphisrm.

A new apparatus for investigating stress,deformation and seepage coupling properties of rock fractures

A true triaxial apparatus which is composed of three units was presented.The apparatus allows for investigations on deformation and seepage behaviors of a single rock fracture subjected to lateral stress and normal stress.The first unit has three jacks which can apply loads independently in three orthogonal directions.The second unit is used to supply water inflow,control seepage pressure and measure flow velocity in real time.The third unit is for measuring the normal deformation of rock fractures.Some tests for investigating the normal deformation and seepage behaviors of rock fractures subjected to normal and lateral loads on hard granite specimens with an artificial persistent fracture,were introduced.The results show that both the normal deformation and the hydraulic conductivity are influenced not only by the normal stress but also by the lateral stress.It is also shown that the aperture and the hydraulic conductivity decrease with the increasing normal stress but increase with the increasing lateral stress and both the aperture and the hydraulic conductivity obey exponential relationships with the normal stress and the lateral stress.

Existence and Uniqueness of Nested Regular Quadrilateral Central Configurations

Two cases of the nested configurations in R3 consisting of two regular quadrilaterals are discussed. One case of them do not form central configuration, the other case can be central configuration. In the second case the existence and uniqueness of the central configuration are studied. If the configuration is a central configuration, then all masses of outside layer are equivalent, similar to the masses of inside layer. At the same time the following relation between r(the ratio of the sizes) and mass ratio b = m/m must be satisfied in which the masses at outside layer are not less than the masses at inside layer, and the solution of this kind of central configuration is unique for the given ratio (6) of masses.

On the Elliptic Equation △u+K(x)e^(2u)=0 with K(x) Positive Somewhere

This paper considers the existence problem of an elliptic equation, which is equivalent to the prescribing conformal Gaussian curvature problem on R^2. An existence result is proved. In particular, K（x） is allowed to be unbounded above.

Some Growth Rates of Certain Holomorphic Maps

In this paper we discuss some properties of h olomorphic maps between Kahler manifolds with certain curvature restrictions.

The Uniqueness and Nonexistent Results for Some Nonlinear Partial Equations on Riemannian Manifolds

The paper studies a class of nonlinear elliptic partial differential equations on a compact Riemannian manifold （M,g） with some curvature restriction. The authors try to prove some uniqueness and nonexistent results for the positive solutions of the equations concerned.

Some Aspects of the Behavior for Orthotropic Thin Plates with Clamped Edges

In most structural applications, composite structures can be idealized as beams, plates or shells. The analysis is reduced from three-dimensional elasticity problem to a one-dimensional, or two-dimensional problem, based on certain simplifying assumptions that can be made because the structure is thin. In this article is presented the mathematical model properly thin orthotropic plates, based on simplifying assumptions Love- Kirchhoff and small deformations. Proposed analytical solutions are considered both for solving equation orthotropic rectangular plates and for modal analysis, in the case of plates with clamped edges. The purposed solutions were analysed considering a FEM solution for comparison and the experimental test results.

Analytical Approaches of Composite Rectangular Thin Plates

The purpose of the present study was to explore and subsequently establish a technique for determination of analytical solutions for the differential equation for composite thin plates. The considered reasons for the solutions were to exactly satisfy the boundary conditions and to verify as close as possible the differential equation of the plate. There are studied two solutions for orthotropic plate with clamped edges, and made comparisons with the solutions presented by Reddy [1] and with the exact solution by Timoshenko and Woinowsky. The models are based on the CLPT （classical laminated plate theory）. The Ritz method, in conjunction with the weighted residue method for the coefficients calculation, is used to analytically determine the bending solutions of orthotropic laminated plates subjected to uniform pressure on the bottom laminate. The purposed solutions were critically analysed considering a FEM （finite element method） solution for comparison. Finally, it is presented the experimental device and the experimental test results, as well. Fabrics have been incorporated into two composite plates were required scalps on one direction, thus ensuring different elasticity modules on both directions. Thorough comparison between analytical solutions, numerical results and experimental data is performed and a good agreement is obtained.

Glass Formation of n-Butanol： Coarse-grained Molecular Dynamics Simulations Using Gay-Berne Potential Model

Using coarse-grained molecular dynamics simulations based on Gay-Berne potential model, we have simulated the cooling process of liquid n-butanol. A new set of GB parameters are obtained by fitting the results of density functional theory calculations. The simulations are carried out in the range of 290-50 K with temperature decrements of 10 K. The cooling characteristics are determined on the basis of the variations of the density, the potential energy and orientational order parameter with temperature, whose slopes all show discontinuity. Both the radial distribution function curves and the second-rank orientational correlation function curves exhibit splitting in the second peak. Using the discontinuous change of these thermodynamic and structure properties, we obtain the glass transition at an estimate of temperature Tg=1204.10 K, which is in good agreement with experimental results 1104-1 K.