静电陀螺转子用铍材的基本要求

通过对静电陀螺仪空心转子的功能特性分析，确认铍材是用作空心转子材料的唯一选择。通过对目前国内外铍材的现状的分析，提出空心转子用铍材的主要技术要求，该要求也适用于实心小球铍材。     

Fracture toughness of CIP-HIP Beryllium at elevated temperatures

The fracture toughness of CIP-HIP Beryllium was determined using the short bar fracture toughness (K_IcSB) method. The K_IcSB value measured was 10.96 MPa√m at room temperature. This falls well within the expected range of 9 to 12 MPa√m as observed from previous fracture toughness measurements of beryllium. Toughness increased rapidly between 400°F and 500°F reaching a value of 16.7 MPa√m at 500°F.     

Relatively Compact Orbits and Compact Attractors for a Class of Nonlinear Evolution Equations

In the present paper we consider the nonlinear evolution equation u+AuG(u), where A:D(A)XX is m-accretive with (I+A)^–1 compact for some >0, and is continuous, and we prove that the orbit is relatively compact if and only if u is uniformly continuous, and both u and G^u are bounded on . In the same spirit, we derive conditions for orbits of bounded sets to have compact attractors. Some consequences and an example from age-structured population dynamics illustrate the effectiveness of the abstract result.     

Dissipation and Compact Attractors

We present an approach to the study of the qualitative theory of infinite dimensional dynamical systems. In finite dimensions, most of the success has been with the discussion of dynamics on sets which are invariant and compact. In the infinite dimensional case, the appropriate setting is to consider the dynamics on the maximal compact invariant set. In dissipative systems, this corresponds to the compact global attractor. Most of the time is devoted to necessary and sufficient conditons for the existence of the compact global attractor. Several important applications are given as well as important results on the qualitative properties of the flow on the attractor.     

Cu/Ni-P多层膜的制备及其摩擦学性能研究

用电沉积方法制备了软硬层交替的Cu／Ni-P多层膜，用原子力显微镜观察分析了多层膜的表面形貌，用X射线衍射仪测定了其相结构；采用动一静摩擦系数精密测量装置考察了多层膜的摩擦学性能和摩擦磨损机制；采用扫描电子显微镜观察分析了其磨损表面形貌．结果表明：Cu／Ni-P多层膜与钢球对摩时具有较好的抗磨减摩性能；在低载荷和低滑动速度下，多层膜的磨痕表面存在擦伤痕迹和较浅的犁沟；在高载荷下多层膜发生严重粘着磨损和剥落。     

Compact waves on planar elastic rods

Planar Kirchhoff elastic rods with non-linear constitutive relations are shown to admit traveling wave solutions with compact support. The existence of planar compact waves is a general property of all non-linearly elastic intrinsically straight rods, while intrinsically curved rods do not exhibit this type of behavior.     

Weighted Compact Scheme for Shock Capturing

In this paper a new class of finite difference schemes - the Weighted Compact Schemes are proposed. According to the idea of the WENO schemes, the Weighted Compact Scheme is constructed by a combination of the approximations of derivatives on candidate stencils with properly assigned weights so that the non-oscillatory property is achieve when discontinuities appear. The primitive function reconstruction method of ENO schemes is applied to obtain the conservative form of the Weighted Compact Scheme. This new scheme not only preserves the characteristic of standard compact schemes and achieves high order accuracy and high resolution using a compact stencil, but also can accurately capture shock waves and discontinuities without oscillation. Numerical examples show the new scheme is very promising and successful.     

Fredholm and Compact Mappings Sharing a Value

1　ＰｒｅｌｉｍｉｎａｒｉｅｓＩｎｔｈｉｓｐａｐｅｒ,ｗｅａｓｓｕｍｅｔｈａｔＸ ,ＹａｎｄＺａｒｅＢａｎａｃｈｓｐａｃｅｓｏｖｅｒＫ =ＲｏｒＫ =Ｃ .ＯｎｅｍｅｔｈｏｄｔｏｓｏｌｖｅｔｈｅｅｑｕａｔｉｏｎＦ(ｘ) =0 ( 1 )ｉｓｔｈｅｃｏｎｔｉｎｕａｔｉｏｎｍｅｔｈｏｄ[1- 10 ].Ｔｈｉｓｍｅｔｈｏｄｃｏｎｓｉｓｔｓｏｆｅｍｂｅｄｄｉｎｇ ( 1 )ｉｎａｃｏｎｔｉｎｕｕｍｏｆｐｒｏｂｌｅｍｓＨ(ｔ,ｘ) =0 ,　　 0 ≤ｔ≤ 1 ,( 2 )ｗｈｅｒｅ ( 2 )ｉｓｅａｓｉｌｙｓｏｌｖｅｄｗｈｅｎｔ=0 .Ｉｆｉｔｉｓｐｏｓｓｉｂｌｅ…     

Dynamical Compact Elastic Bodies in General Relativity

We prove the local existence of solutions to the Einstein-Elastic equations that represent self-gravitating, relativistic elastic bodies with compact support.     

Compact bend for a supersonic two-dimensional flow

A channel realizing a compact bend in the class of channels proposed by Stepanov and Oswatitsch [1, 2] and based on the use of a “potential vortex” flow has been constructed and investigated numerically. The dependence of the size of the channel on the Mach number of the initial flow has been obtained numerically. A bend is proposed on the basis of multiple use of isentropic compression and rarefaction waves and regions of their interaction. Such flows have already been obtained and analyzed [3, 4]. Such channels are compared and it is shown, in particular, that at small Mach numbers of the initial flow the newly proposed channel is smaller than the channel based on the use of the potential vortex flow.     

Compact Energy Storage Device for Electromagnetic Launchers of Solids

Numerical study has been performed to investigate the operating characteristics and modes of an energy storage device based on a pulsed magnetohydrodynamic generator and a step-up transformer with a stored energy of 25 and 50 MJ and a secondary winding current of 250 kA at the final stage of operation. The operating parameters of such storage devices with rail launchers operating in the mode of rapid-fire launching of several projectiles were calculated.     

A Formulation of Anisotropic Elastic Damage Using Compact Tensor Formalism

An anisotropic elastic-damage model for initially-isotropic materials is presented. The model is based on a pseudo-logarithmic second-order damage tensor rate. To derive the complete expression of the tangent stiffness entering the rate constitutive law, various tensor operations and derivatives of tensor functions must be developed. Such derivations have been performed in compact form. Some useful tensor derivatives and a table of tensor algebra operations are given in Appendix. This note should interest engineering researchers involved in the development of constitutive models through tensor formalism. This revised version was published online in July 2006 with corrections to the Cover Date.     

Compact robust FAT control of rigid robots with state constraints

Nonlinear Dynamics - This paper develops a robust regressor-free controller for n-link robots with state constraints. We use the function approximation technique to represent the uncertain robot...     

Photoelastic Method for Analyzing Residual Stresses in Compact Disks

The issues of size and shape stability are especially important in modern high technologies, in particular, in the compact disk technology. Stability in this case is substantially affected by residual stresses that occur in disks because of the imperfection of their production process. The objective of the present study was to develop a simple optical method to estimate the stress state of compact disks.     

Fixed Points on Two Complete and Compact Metric Spaces

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｆｏｌｌｏｗｉｎｇｒｅｌａｔｅｄｆｉｘｅｄｐｏｉｎｔｔｈｅｏｒｅｍｗａｓｐｒｏｖｅｄｉｎ [1 ] .Ｔｈｅｏｒｅｍ 1　Ｌｅｔ(Ｘ ,ｄ)ａｎｄ (Ｙ ,ρ)ｂｅｃｏｍｐｌｅｔｅｍｅｔｒｉｃｓｐａｃｅｓ,ｌｅｔＴｂｅａｍａｐｐｉｎｇｏｆＸｉｎｔｏＹａｎｄｌｅｔＳｂｅａｍａｐｐｉｎｇｏｆＹｉｎｔｏＸｓａｔｉｓｆｙｉｎｇｔｈｅｉｎｅｑｕａｌｉｔｉｅｓρ(Ｔｘ,ＴＳｙ) ≤ｃｍａｘ ｄ(ｘ ,Ｓｙ) ,ρ(ｙ,Ｔｘ) ,ρ(ｙ,ＴＳｙ) ,ｄ(Ｓｙ ,ＳＴｘ) ≤ｃｍａｘ ρ(ｙ ,Ｔｘ) ,ｄ(ｘ,Ｓｙ) ,ｄ(ｘ ,ＳＴｘ)…     

超高分子量聚乙烯对聚酰胺摩擦磨损行为的影响

采用双螺杆挤出机制备聚酰胺/超高分子量聚乙烯(PA66/UHMWPE)和聚酰胺/超高分子量聚乙烯/马来酸酐接枝高密度聚乙烯(PA66/UHMWPE/MAH-g-HDPE)共混物,采用傅立叶转换红外光谱仪分析共混体系的结构,同时评价其机械性能及摩擦磨损性能.结果表明:加入MAH-g-HDPE相容剂可以使共混体系的相容性得到改善,提高共混物的机械性能;具有平整分子结构的UHMWPE有利于改善PA66的摩擦磨损性能,当摩擦偶件的转移层达到饱和状态后,共混物的耐磨性与其力学性能相关;共混物在摩擦过程中表现出严重的塑性变形和粘着磨损,但在共混体系的摩擦过程中,对摩擦磨损性能起主要作用的是受热软化的UHMWPE在磨损表面形成低剪切强度的界面层,从而使得PA66的摩擦磨损性能明显改善.     

陶瓷／硬质合金复合片残余应力分析

推导了由于热膨用录同，在热压烧结陶瓷／硬质合金复合片内引起的残余正应力和界面剪应力计算公式；分析了平行和垂直于复合片界面裂纹产生的原因及影响因素，所得结论对双材料的设计有一定的指导作用。