我国力车胎行业现状与展望

介绍了2002年我国力车胎的行业现状。近年的发展及展望。并着重描述了力车胎专用设备的新发展。     

OFDM技术及其应用

首先对OFDM的发展以及应用做了简要的介绍,然后讨论了当前OFDM研究过程中的两个关键技术问题,最后展望了OFDM的未来发展。     

铸型尼龙改性的研究进展

铸型尼龙产品广泛地用于各种机械零件，改性后的铸型尼龙，可克服其自身的缺点，满足工业应用的要求。文章就我国近年来在铸型尼龙改性研究方面的情况及不同的改性方法做了详细的介绍。     

Finite element analysis of partly wrinkled reinforced prestressed membranes

Wrinkling is a well known phenomenon experimented by tension membranes in Civil Engineering applications. This paper will present an efficient numerical technique for the computational simulation of such wrinkles in a prestressed membrane. In particular, the relaxed energy approach (Pipkin in IMA J Appl Math 36:85–99, 1986) is particularized for prestressed membranes (Gil in Textile composites and inflatable structures, CIMNE, 2003) undergoing moderate strains. Wrinkling conditions in terms of the Euler-Lagrange finite deformation tensor along principal directions will be obtained. This will provide a framework to describe properly the initial instant when wrinkles start to be encountered in a prestressed Saint Venant–Kirchhoff hyperelastic membrane. Subsequently, a modified Helmholtz’s free energy functional will be introduced with the purpose of describing the modified constitutive behaviour of the continuum after the onset of wrinkling. Consistent derivations of the stress tensor as well as the constitutive tensor will de depicted. The results will be particularized for membranes and cables in a Finite Element discretization basis. Some numerical examples will prove the accuracy and robustness of the described algorithm.     

砼坝裂缝稳定性分析

通过比较线弹性断裂力学中的两种计算应力强度因子的方法，外推法和奇异单元法，得到相应的结论；并以某砼坝下游部位出现裂缝为例，分析在不利荷载作用下裂缝的稳定性。     

基于双秘钥的高强度公钥密码体制的研究

该文研究双秘钥公开钥密码体制,它不同于一般的只有一个秘密密钥的公开钥密钥体制,而是使用两个秘密密钥。要攻破它必须同时解决两个数学难题(素因子分解和求离散对数),从而大大增加了破译难度。     

Mechanism for the Peritectic Reaction and Growth of Aligned Grains in YBa2Cu3O6+x

It is experimentally observed that the peritectic reaction, 211 + liquid → 123, can be driven essentially to completion in 1 h at an undercooling of only ∽30°C. The kinetic data, together with the observed microstructures, are inconsistent with the normal mechanism of the peritectic reaction. It is proposed that the mechanism of the reaction involves dissolution of 211 particles into the liquid and precipitation of solid 123. The aligned grain structure is explained through sympathetic nucleation of new 123 grains on existing grains.     

Study on Oxygen-Sensing Properties of LaNiO3 Thin Films

The synthesis of rare-earth perovskite-type composition thin films of LaNiO₃ by means of the inorganic-sol-gel (ISG) method was studied. The structural stability under high temperature in reducing atmospheres and the oxygen-sensitivity mechanism of the LaNiO₃ thin films were examined. It is shown that under the experimental conditions, LaNiO₃ decomposes and the valance states of nickel are +2 and +3.     

Compact equivalent circuit model of two‐layer spiral inductors

A compact lumped‐element equivalent circuit model of two‐layer integrated spiral inductors on silicon substrates is developed in this article. Based on this proposed model, excellent agreements are achieved between the measured and simulated S‐parameters for different inductors. Also, both self‐ and mutual inductances of two‐layer inductors are accurately extracted, and their overall performances are understood clearly. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 148–153, 2003.