Use of superposition principle to derive a general mathematical model to simulate one-to-one, one-to-multi and multi-to-multi saw filter designs

This paper explains and summarizes a new attempt to derive a general mathematical model [GMM] to simulate surface acoustic wave (SAW) filters, using the superposition principle and delta function model. GMM can be used to simulate One-to-One, One-to-Multi and Multi-to-Multi SAW filter devices. The simulation program was written using MATLAB (the language of technical computing). Four-design structures (One-to-One, One-to-Two, One-to-Three and Ten-to-Ten) ware selected to test the correctness of GMM. The frequency response of the simulation and test results are similar in center frequency and 3-dB bandwidth, but the insertion loss is different, because of some second order effects (Issa Haitham, 1999).     

An analytical model for predicting sheet springback after V-bending

INTRODUCTION As an important manufacturing method, bending has been widely used in modern industries to produce stamping parts such as frames, channels, braces, brackets and other structural parts. The understanding and development of bending mechanics are aimed at achieving two kinds of information which are very important for industrial production. One is to predict springback for dies design and compensation in order to obtain high dimension accuracy of bending parts. The other is to …     

Spectral Characterizations of Veronese Surface in S~4

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｌｅｔ (Ｍ ,ｇ)ｂｅａｃｏｍｐａｃｔｏｒｉｅｎｔｅｄａｎｄｃｏｎｎｅｃｔｅｄＲｉｅｍａｎｉａｎｍａｎｉｆｏｌｄｏｆｃｌａｓｓＣ∞ ｗｉｔｈｏｕｔｂｏｕｎｄａｒｙ ;ΔｂｅｔｈｅＬａｐｌａｃｉａｎａｃｔｉｎｇｏｎ ｐ ｆｏｒｍｓｆｏｒｐ =0 ,1,… ,ｎ .Ｗｅｋｎｏｗｔｈａｔｔｈｅｅｉｇｅｎｖａｌｕｅｓｆｏｒｍａｎｏｎ ｄｅｃｒｅａｓｉｎｇｓｅｑｕｅｎｃｅｄｅｎｏｔｅｄｂｙｓｐｅｃｐ(Ｍ ) ={ 0≤λ0 ,ｐ≤λ1,ｐ≤… }ｗｈｅｒｅｅａｃｈｅｉｇｅｎｖａｌｕｅｉｓｒｅｐｅａｔｅｄｍａｎｙ…     

积分运算中几种常见错误剖析

针对多元函数积分运算中的几种常见错误,即:对被积函数及积分区域的对称性、面积分及重积分的积分区域、曲面积分的投影区域等几个方面进行了剖析,并给出几点注意事项.     

圆柱周围湍流场的数值模拟

In practical problems, the variation of the free surface around a circular pier is severe. For the Fluent CFD, the multiphase flow models cannot be used together with the LES model to calculate the free surface. Present paper provides a two-step method which joints the 2D compressible ideal-gas equations and the LES model to calculate the 3D flow field with free surface around the pier. The effects of the free surface on the flow structures are studied in detail.     

响应曲面法优化无籽刺梨多酚提取工艺研究

文章采用三因素三水平的响应曲面分析方法优选了无籽刺梨多酚的提取工艺.结果表明,提取金刺梨多酚的最佳方案为:酒精浓度72%、固液比1:13、提取时间23 min,用此条件下提取实际测得的平均提取含量为1.8117%.     

冰表面上硝酸溴与水反应的理论研究

采用量子化学中的密度泛函理论计算方法B3LYP/6-311++G(3df,3pd)对反应B rONO2+H2O=HNO3+HOB r进行了研究.研究发现该反应随着水团簇中分子数目的增加反应的势垒逐渐减小,当水分子数为2时,该反应已经是一个快反应了.计算结果表明在冰表面上在平流层条件下标题反应是通过结构催化和水催化进行反应的.其反应条件即使在南极的夏季和北极极低的温度下也极易满足.研究结果与现阶段已有的实地观察和实验结果相一致.     

白及多糖响应曲面法优化提取工艺及抑菌活性研究

研究影响白及多糖提取的因素,优化其提取工艺及探究其抑菌活性。通过单因素和响应曲面法,选择提取次数、水提时间、水提温度、液料比4个因素筛选白及多糖的最佳水提工艺,蒽酮-硫酸法测定白及多糖的含量,滤纸片-抑菌圈法测定白及多糖对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌及黑曲霉菌的抑菌作用。经由以上实验设计可得白及多糖最佳提取工艺为:提取次数1次、水提时间2.2 h、水提温度77℃、液料比39.27 mL/g,白及多糖得率31.09%;白及多糖对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌及黑曲霉菌均有抑制作用。     

锌电极在充放电后表面形貌的分形研究

在含有和不含有添加剂的 KOH溶液中对 Zn电极进行充放电实验 ,用透射电镜观测经充放电 5次后的 Zn电极表面形貌 ,并计算其分形维数     

求两自由曲面交线的一种新方法

给出了一种求两自由曲面交线的新方法.该方法具有算法简单、数据结构合理、结果较为精确的特点.