排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
TBAB修饰的负载型Wacker催化剂催化甲醇羰基化合成碳酸二甲酯 总被引:7,自引:0,他引:7
自 1 95 9年 Smidt等 [1]发现均相 Pd Cl2 - Cu Cl2 体系可高效率直接选择性氧化乙烯制乙醛以来 ,Wacker催化过程已成为乙醛工业生产的主要方法 .为解决 Wacker催化体系腐蚀性强及催化体系与产物难以分离等弊端 ,将均相 Wacker(Pd Cl2 - Cu Cl2 )催化剂固载化成为备受关注的研究课题[2 ] .多相Wacker催化剂不仅成功地应用于选择性氧化低碳烯烃制醛和酮 [3 ,4 ] ,还用于 CO深度氧化 [5~ 7] .碳酸二甲酯 (DMC)的合成与应用研究是目前绿色化学前沿课题 .在众多的 DMC合成方法中 ,常压气相法因其工艺简单、对设备无腐蚀以及产品易分离… 相似文献
2.
In this paper, a nonautonomous impulsive neutral-type neural network with delays is considered. By establishing a singular impulsive delay differential inequality and employing contraction mapping principle, several sufficient conditions ensuring the existence and global exponential stability of the periodic solution for the impulsive neutral-type neural network with delays are obtained. Our results can extend and improve earlier publications. An example is given to illustrate the theory. 相似文献
3.
太阳池非对流层最佳厚度及最大效率数值模拟 总被引:3,自引:0,他引:3
本文对现有的太阳池辐射透射模型及稳态热效率模型进行了改进,改进的模型既考虑了池水浊度的影响又考虑了池内多重反射的影响,更接近实际情况。在改进的稳态热效率模型基础上,通过数值模拟的方法,对太阳池非对流层最佳厚度及其最大效率的相关影响因素作了较为详细的分析和讨论。认为太阳池非对流层最佳厚度及其最大效率取决于太阳池尺寸和结构、太阳辐射强度、储热层和上对流层的温差、太阳辐射在水中的透射率、池底反射率、水浊度、池水的物理特性以及池深度等综合因素,其中,△T/I0(储热层和上对流层的温差与水面太阳辐射强度的比值)是影响太阳池非对流层最佳厚度的主要因素,这为太阳池高效运行提供了理论指导。 相似文献
4.
Huang Xiao-Li Shao-Cheng Hou Lin-Cheng Wang Xue-Xi Yi 《Central European Journal of Physics》2012,10(4):947-952
Taking a two-level system interacting with a two-band environment as an example, we discuss the non-Markovianity and initial system-environment correlations for the generalized Lindblad master equation by using a recently introduced measure given by Breuer et al. Our results show that the initial states of the environment and initial system-environment correlations have strong effects on the non-Markovianity of the reduced system. Moreover, we also show that information and energy can flow in different directions, i.e., energy flows to the system while information flows from the system, which is quite different from previous results. 相似文献
5.
Robust stability analysis for Markovian jumping stochastic neural networks with mode-dependent time-varying interval delay and multiplicative noise 下载免费PDF全文
This paper is concerned with the problem of robust stability for a
class of Markovian jumping stochastic neural networks (MJSNNs)
subject to mode-dependent time-varying interval delay and
state-multiplicative noise. Based on the Lyapunov--Krasovskii functional
and a stochastic analysis approach, some new delay-dependent
sufficient conditions are obtained in the linear matrix inequality
(LMI) format such that delayed MJSNNs are globally asymptotically
stable in the mean-square sense for all admissible uncertainties. An
important feature of the results is that the stability criteria are
dependent on not only the lower bound and upper bound of delay for all
modes but also the covariance matrix consisting of the correlation
coefficient. Numerical examples are given to illustrate the
effectiveness. 相似文献
6.
Robust lag synchronization between two different chaotic systems via dual-stage impulsive control 下载免费PDF全文
In this paper, an improved impulsive lag synchronization scheme for
different chaotic systems with parametric uncertainties is proposed.
Based on the new definition of synchronization with error bound and
a novel impulsive control scheme (the so-called dual-stage impulsive
control), some new and less conservative sufficient conditions are
established to guarantee that the error dynamics can converge to a
predetermined level, which is more reasonable and rigorous than the
existing results. In particular, some simpler and more convenient
conditions are derived by taking the same impulsive distances and
control gains. Finally, some numerical simulations for the Lorenz system
and the Chen system are given to demonstrate the effectiveness and
feasibility of the proposed method. 相似文献
7.
A scheme for the impulsive control of nonlinear systems with
time-varying delays is investigated in this paper. Based on the
Lyapunov-like stability theorem for impulsive functional
differential equations (FDEs), some sufficient conditions are
presented to guarantee the uniform asymptotic stability of
impulsively controlled nonlinear systems with time-varying delays.
These conditions are more effective and less conservative than those
obtained. Finally, two numerical examples are provided to
demonstrate the effectiveness of the proposed method. 相似文献
8.
In this paper, the decentralized stabilization control approach based on the dynamic surface control (DSC) is proposed for
a class of large-scale interconnected stochastic nonlinear systems. The proposed approach combined the existing dynamic surface
control (DSC) with back-stepping technique. This approach can overcome the problem of “explosion of complexity” inherent in
the back-stepping method. Thus, the proposed control approach is simpler than the traditional back-stepping control method
for the large-scale interconnected stochastic nonlinear systems. The stability analysis shows that all the signals in the
closed-loop system are uniformly ultimately bounded (UUB). Finally, an example is provided to illustrate the effectiveness
of the proposed control system. 相似文献
9.
10.
利用SOLPS5.0模拟研究东方超环托卡马克(EAST)高约束模式时的刮削层等离子体. 在高约束模式放电实验参数(第36291炮)的限制下,通过调整上游区径向反常输运系数来实现高约束模式模拟,在上游电子密度和温度与实验符合的条件下能够很好地进行下游区模拟. 在实现高约束模拟的基础上又分别研究了漂移项对偏滤器靶板能流不对称性的影响和上游能流衰减宽度对靶板能流密度峰值的影响. 通过模拟发现,漂移是导致EAST放电内外靶板不对称性的主要原因,增大上游能流衰减宽度可以明显降低入射到靶板的峰值热流,并且偏滤器区辐射以及与中性粒子的相互作用减小了能流的衰减宽度对达到靶板能流的影响.
关键词:
托卡马克
高约束模式
SOLPS5.0
漂移 相似文献