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在分析软硬阈值去噪特点的基础上,提出一种改进的小波阈值函数。根据Langmuir 探针I-V 特性曲线的特点,提出一种改进的标准差估算方法来计算小波阈值。采用基于改进标准差和改进阈值函数的小波对探针特性曲线进行去噪,仿真结果表明,改进的方法取得了良好的去噪效果,提高了信号的信噪比,降低了均方误差,去噪效果优于传统阈值去噪方法。 相似文献
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The two title compounds obtained by solid state reaction at high temperature were char-acierized as isomorphism by single--crystal X--ray diffraction. The space group of both crys-tals is C_(2v)~4-Pma2, with lattice constants a = 7.955(1), b=6.258 (1), c=7 .203(2)A forI, and a =7.914 (1), b=6.237 (1), c=7.236 (1) ? for Ⅱ, Z=2. The structures were de-termined by normal method and refined to the final R = 0.074 and 0.083, respectively. Theresults show that the structure may be regarded as building by cluster unit with formulaNi_2M_2Te_4 (M =Nb or Ta) in which two Ni atoms and two M atoms form a rhombus, whilethe Te atoms are distorted tetrahedrally coordinated with both kinds of metal atoms. In thecluster unit there exist interactions between Ni atoms as well as between Ni and M atoms.In addition, all the cluster units are linked together not only by bridging Te atoms, but alsoby weaker metal-metal interactions, so as to form two--dimensional network. Therefore, thestructure may be represented by the for 相似文献
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十二烷基三甲氧基硅烷(DMS)和硬脂酸(STA)对α-Al2O3载体上二次生长合成的silicalite-1膜进行修饰来提高其表面疏水性。红外光谱和接触角测试结果表明,改性后改性剂以化学键的形式结合于分子筛膜表面,膜表面由亲水变为疏水。表面改性的最佳预处理温度为150℃,改性剂的最佳质量分数为10%。进一步研究了膜表面润湿特性和热稳定性之间的关系,其中DMS改性后的分子筛膜在空气中经250℃高温处理后仍保持疏水性不变。在乙醇/水分离应用中,高温脱除模板剂后缺陷的孔径分布在1~5nm时,表面改性后乙醇分离因子较改性前可提高5倍,最高可达21.6。 相似文献
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定义离子极化力参数 gi.在分子拓扑图的邻接矩阵基础上 ,由 gi 建构极化力连接性指数 mG ,其中 0 G、1G对无机分子有良好的结构选择性 .计算了 6 4种碱金属、碱土金属的氧化物、卤化物、硫化物、硒化物等的 0 G、1G ,发现它们的标准熵与分子的大小及分子中的原子数正相关 ,而与分子中离子的极化力负相关 .这与其标准熵的递变规律相一致 .所以 ,化合物的 0 G、1G必然与其标准熵表现出良好的相关性 .研究结果表明 ,其预测值和实验值基本吻合 ,优于Latimer法以及Randic Kier连接性指数 相似文献