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991.
Gabriela Huminic Alexandru Vrdaru Angel Huminic Claudiu Fleac Florian Dumitrache Ion Morjan 《International journal of molecular sciences》2022,23(6)
In the current paper, a new hybrid nanofluid based on graphene oxide sheets and silicon nanoparticles is proposed for thermal applications. GO sheets and Si nanoparticles with different mixture ratios are dispersed in distilled water. Dynamic viscosity is measured at temperatures within the range 20–50 °C and the values are compared to the results available in the literature. The results indicated that the viscosity increases with increasing the mixture ratio of graphene oxide. A new correlation for the dynamic viscosity based on the experimental findings is proposed. Finally, the criteria for the performance of new hybrid nanofluid for thermal applications are analyzed. 相似文献
992.
以某款双行星排混合动力公交车为样车,针对控制变量柴油机转速的离散控制和连续控制分别提出基于双深度Q网络(double deep Q-learning, DDQN)和基于双延迟深度确定性策略梯度(twin delayed deep deterministic policy gradients, TD3)的能量管理策略,并使用优先级经验回放对策略进行优化。运用仿真试验,研究样车在C-WTVC工况下的能量管理特性。通过与动态规划策略(dynamic programming, DP)进行对比发现:DDQN和TD3策略收敛速度快,具有较强的自适应能力;与DP策略相似,DDQN和TD3策略在控制逻辑上均表现为低速和较低转矩时纯电驱动,高速和较高转矩时混合驱动;三种策略下柴油机均主要工作于中低转速区间,且TD3策略可以对柴油机转速进行连续控制;DDQN和TD3策略的百公里油耗分别为19.51L和19.48L,燃油经济性均达到DP策略的93%,研究证明了DDQN和TD3策略的有效性。 相似文献
993.
以正硅酸乙酯(TEOS)、二乙氧基二甲基硅烷(DDS)、有机硅烷偶联剂(MPTMS和VTMS)为原料,采用sol-gel法制备了可UV固化的有机硅/SiO2杂化涂料,并考察了原料配比对杂化涂料稳定性的影响。结果表明:DDS-MPTMS/SiO2比DDS-VTMS/SiO2稳定性更好;乙醇用量增加有利于提高储存稳定性;随着陈化时间延长,杂化涂料粒径变大,分布变宽,漆膜透光率下降。当各组分的摩尔比为nDDS/nTEOS=2/3,nMPTMS/nTEOS=1/3,nHCl/nSi-O=0.006,nEtOH/nSi-O=1,nH2O/nSi-O=0.6时,杂化涂料稳定性最佳。在此条件下制备的杂化涂料平均粒径3.6 nm,凝胶时间大于300 d,经UV固化后漆膜的性能最好。 相似文献
994.
995.
Jochen Aβfalg 《国际自动化与计算杂志》2007,4(2):141-148
This paper presents an internal model approach for modeling and diagnostic functionality design for nonlinear systems operating subject to single- and multiple-faults. We therefore provide the framework of structured augmented state models. Fault characteristics are considered to be generated by dynamical exosystems that are switched via equality constraints to overcome the augmented state observability limiting the number of diagnosable faults. Based on the proposed model, the fault diagnosis problem is specified as an optimal hybrid augmented state estimation problem. Sub-optimal solutions are motivated and exemplified for the fault diagnosis of the well-known three-tank benchmark. As the considered class of fault diagnosis problems is large, the suggested approach is not only of theoretical interest but also of high practical relevance. 相似文献
996.
针对现有的点云滤波算法存在的精度丢失和收缩的不足,提出邻域自适应选择的算法,有效地改善了点云滤波中丢失精度的问题.算法首先针对原始点和均值点滤波出现的收缩问题,提出混合增采样策略.其次采用邻域自适应选择保持特征部分的滤波精度.最后定义每个采样点以对应的似然函数,并按照其梯度方向进行迭代,通过最大似然估计得到最优滤波结果... 相似文献
997.
998.
Role of carbonate phase in ceria–carbonate composite for low temperature solid oxide fuel cells: A review 下载免费PDF全文
Ceria–salt composites represent one type of promising electrolyte candidates for low temperature solid oxide fuel cells (LT‐SOFCs), in which ceria–carbonate attracts particular attention because of its impressive ionic conductivity and unique hybrid ionic conduction behavior compared with the commonly used single‐phase electrolyte materials. It has been demonstrated that the introduction of carbonate in these new ceria‐based composite materials initiates multi new functionalities over single‐phase oxide, which therefore needs a comprehensive understanding and review focus. In this review, the roles of carbonate in the ceria–carbonate composites and composite electrolyte‐based LT‐SOFCs are analyzed from the aspects of sintering aid, electrolyte densification reagent, electrolyte/electrode interfacial ‘glue’ and sources of super oxygen ionic and proton conduction, as well as the oxygen reduction reaction promoter for the first time. This summary remarks the significance of carbonate in the ceria–carbonate composites for low temperature, 300–600 °C, SOFCs and related highly efficient energy conversion applications. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
999.
The problem of exponential mean-square stability of two-time scale, linear stochastic hybrid systems has been studied in this paper. To obtain the sufficient conditions of stability, two basic approaches of stability analysis: for one-time hybrid systems with a Markovian switching rule as well as switching rule and singularly perturbed nonhybrid systems, were combined. The Lyapunov techniques were used in both approaches. 相似文献
1000.
In this study, a diffractive-refractive hybrid objective lens (DHOL) compatible with multi-type optical discs (Blu-ray Disc (BD), China Blue High-Definition Disc (CBHD), DVD and CD) was designed and fabricated. The surface of the DHOL was an aspherical (refractive) substrate superimposed on a diffractive sub-structure, and by using ultra-precision single point diamond turning, the form error was reduced to be less than λ/4. However, because of the finite dimensions of the tool radius (R), the pitch of the diffractive structure must be larger than R. This limits the performance of the DHOL and has a bigger effect on the diffractive performance than on the refractive performance. To counteract the limitation, a novel refractive compensation method is proposed. Through superimposing a small refractive curvature, a significant improvement in the diffractive performance was achieved. By reconstructing the wavefront aberration using Zernike expansion and taking the horizontal rotation angle, tool radius and usable cutting edge into account, an optimal design was determined. The optimal design was fabricated and found to perform satisfactorily. 相似文献