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排序方式: 共有88条查询结果,搜索用时 15 毫秒
1.
Cu,Pd-ZSM-5上NO分解和CO氧化的催化作用 总被引:4,自引:0,他引:4
双交换Cu,pd-ZSM-5催化剂(Cu交换度为105%,Pd交换度分别为3.4%和33%)对CO氧化反应有活性增强作用,对NO分解反应不存在增强效应.双交换催化剂在于交换程序不同,而表面物种不同,活性组分的分布状态不同,因而有不同的活性.先交换Cu,400℃焙烧后再交换pd的Cu-Pd-ZSM-5催化剂,对上述两类反应的活性存双组分催化剂中均为最高.H_2-TPR谱表明,共交换的Cu-Pd-ZSM-5中尚有部分CuCl+占据了部分交换位置,而使CO氧化活性稍有下降.N_2-DTA和H_2-TPR谱结果表明,Pd交换到Cu-ZSM-5中后,抑制了吸附水和水合铜化合物的形成,由此提高了在200—300℃时氧的吸附量.后者的大小和CO氧化活性有顺变关系.N_2-DTA谱中340—445℃的放热峰可能分别表征了和NO分解活性有关的铜氧桥或把氧桥的形成,该放热峰的峰温愈低,峰面积愈大,则NO分解活性愈高. 相似文献
2.
探讨了有机金属催化剂的组成及其对二氧化碳同环氧丙烷交替共聚产物结构的影响,发现二乙基锌—助剂体系的催化活性按如次顺序递降:二乙基锌—连苯三酚>二乙基锌—间苯二酚>二乙基锌—对苯二胺>二乙基锌—亚乙基脲。若用三异丁基铝代替二乙基锌同连苯三酚构成催化剂,则失去对二氧化碳同环氧丙烷交替共聚反应的活性同时,著者发现二乙基锌—二元芳胺催化体系与二乙基锌—二元酚催化体系的催化活性规律完全不同。 相似文献
3.
Rong Chen Zhijun Qiao Shouming Zhou 《Mathematical Methods in the Applied Sciences》2019,42(18):6999-7010
Considered herein is a two‐component Novikov equations (called Geng‐Xue system for short) with cubic nonlinearities. The persistence properties and some unique continuation properties of the solutions to the system in weighted Lp spaces are established. Moreover, a wave‐breaking criterion for strong solutions is determined in the lowest Sobolev space by using the localization analysis in the transport equation theory, and we also give a lower bound for the maximal existence time. 相似文献
4.
In this paper,the distance-sability of nonlinear discrete system is investigated by meansof the Gauss-Seidel iteration method.Some algebric criteria of the distance-stability are ob-tained.Construction of Lyapunov function is avoided. 相似文献
5.
In this article, based on Lyapunov–Krasovskii functional method and stochastic analysis theory, we obtain some new criteria ensuring mean square stability of trivial solution of a class of impulsive stochastic differential equations with delays. As an application, a class of stochastic impulsive neural network with delays has been discussed. One illustrative example has been provided to show the effectiveness of our results. 相似文献
6.
7.
Stability of functional differential equations (FDE) is an increasingly important problem in both science and engineering. Delays, whether uniform or non-uniform, play an important role in the dynamics of a system. Since non-uniform delay is more general and less focused than uniform delay, this paper concentrates on the stability of high-order neutral functional differential equations (HNFDE) with non-uniform delay, and proposes a sufficient condition for it. This result may be widely helpful, thanks to the frequent emergence of a HNFDE with non-uniform delay in various fields. Its effectiveness is illustrated by some examples. 相似文献
8.
In this paper, we mainly study the well-posedness in the sense of Hadamard, non-uniform dependence, Hölder continuity and analyticity of the data-to-solution map for a cross-coupled Camassa–Holm equation with waltzing peakons and compacton pairs on both the periodic and the nonperiodic case. Using a Galerkin-type approximation scheme, it is shown that this equation is well-posed in Sobolev spaces \(H^{s} \times H^{s},s>5/2\) in the sense of Hadamard, that is, the data-to-solution mapis continuous. In conjunction with the well-posedness estimate, it is also proved that this dependence is sharp by showing that the solution map is not uniformly continuous. Furthermore, the Hölder continuous in the \(H^r \times H^r\) topology when \(0\le r< s\) with Hölder exponent \(\alpha \) depending on both s and r are shown. Finally, applying generalized Ovsyannikov type theorem and the basic properties of Sobolev-Gevrey spaces, we prove the Gevrey regularity and analyticity of the CCCH system. Moreover, we obtain a lower bound of the lifespan and the continuity of the data-to-solution map 相似文献
9.
In this paper, we investigate the behavior of the positive solution of the following Cauchy problem
ut−div(|∇um|p−2∇um)=uq 相似文献
10.
This paper deals with quenching phenomena for a heat equations with coupled singular logarithms boundary fluxes. Under appropriate hypotheses, the non-simultaneous quenching of the solution for the system is proved, and the estimates of quenching rates are given. Then we give a natural continuation of the solution (u,v) after the quenching time when the equations occurs non-simultaneous quenching. Moreover, we identify the heat equations verified by the continuation beyond quenching time, i.e., the equations occurs incomplete quenching. 相似文献