圆管状声波换能器瞬态过程的分析

结合石油测井的实际情况,首次从理论上对常规声波测井仪中采用的圆管状压电陶瓷声波换能器在阶跃电压、冲激电压和正弦间断电压等激励信号的作用下的瞬态过程进行了分析,推导出了在上述几种情况下圆管状压电陶瓷换能器的声源函数和谱函数,并叙述了推导结果在声皮测井中的应用。     

Surface wave modes of printed circuits on ferrite substrates

Surface waves due to a current source on a grounded ferrite slab are investigated. Electromagnetic fields of the structure are in terms of a continuous plane wave spectrum. The spectrum of each field component is obtained numerically through the exponential-matrix method. The surface waves of the structure are extracted from the continuous spectrum by using the residue theorem and the method of steepest descent. Two types of surface waves are found and their properties are described. The surface wave modes found include dynamic surface wave modes which are closely related to the surface waves of a grounded dielectric slab, and magnetostatic surface wave modes which are related to the solution of Laplace's equation for the magnetic potential     

浅析体系转换法和粘贴碳纤维加固法在桥梁加固中的应用

通过对桥梁加固技术的研究，讨论了体系转换法和粘贴碳纤维布加固法的具体应用。     

红外图像序列小目标检测预处理技术

文中就如何复杂背景条件下低信噪比的小目标检测概率问题展开了讨论，提出了用空间高通滤的方法改善图像质量，达以抑制背景噪声，增强小目标的目的，并交坑通滤波和中值滤波做了一个简单的比较，随后采用分层投票表决法对目标进行检测，取得了良好效果。     

Reply to comments on “Error rate performance of theprojection code”

The authors reply to the comments by Koppelaar and Tolhuizen (see ibid. vol.46, no.9, p.573, 1998). They state that the optimum choice of the slopes used to perform the encoding process in a projection code always results in maximizing the minimum Hamming distance so that d=2 ^r     

Two-level optimal output feedback stabilizer design

The paper addresses the design of two-level power system stabilizers using an optimal reduced order model whose state variables are torque angles and speeds. The reduced order model retains their physical meaning and is used to design a two-level linear feedback controller that takes into account the realities and constraints of electrical power systems. The two-level control strategy is used, and a global control signal is generated from the output variables to minimize the effect of interactions. The effectiveness of this controller is evaluated and a multimachine system is given as an example to illustrate the advantages of the proposed method. Responses of the system with a two-level scheme and an optimal reduced order scheme are included for comparative analysis.     

三次方程求根及根的性质

给出实系数三次代数方程三个根的关系式定理。只要知道一个根，由该定理可方便地求出另外两根；对重根也适用，且更方便。     

钛对耐硫变换催化剂性能的影响

利用常压微反色谱、程序升温还原（ＴＰＲ）等技术研究了钛对耐硫变换催化剂性能的影响，结果表明：（１）钛能明显提高耐硫变换催化剂的活性，尤其是在低于６２３Ｋ时活性提高最为明显；（２）工业侧流试验后，含钛样品的保留活性及活性保留率均高于Ｋ８－１１；（３）催化剂中添加助剂ＴｉＯ２后，能显著提高对原料气中Ｈ２Ｓ含量变化的适应能力，因此可以拓宽对原料气的选择范围，对工业生产有着十分重要的现实意义。     

高装填密度装药技术中的选药计算

本文围绕叠片药这一装药技术,对某炮进行了有关选药计算,研究了制式火药与叠片药之间的弧厚配比和质量配比关系,并得出了一些有实用价值的结论.