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51.
In this paper, a dynamic modeling method and an active vibration control scheme for a smart flexible four-bar linkage mechanism featuring piezoelectric actuators and strain gauge sensors are presented. The dynamics of this smart mechanism is described by the Discrete Time Transfer Matrix Method of Multibody System (MS-DTTMM). Then a nonlinear fuzzy neural network control is employed to suppress the vibration of this smart mechanism. For improving the dynamic performance of the fuzzy neural network, a genetic algorithm based on the MS-DTTMM is designed offline to tune the initial parameters of the fuzzy neural network. The MS-DTTMM avoids the global dynamics equations of the system, which results in the matrices involved are always very small, so the computational efficiency of the dynamic analysis and control system optimization can be greatly improved. Formulations of the method as well as a numerical simulation are given to demonstrate the proposed dynamic method and control scheme. 相似文献
52.
Yuning Lou Yajuan Dong Xiaoyong Wang Feirong Gong Min Zhao Zongming Rong 《Journal of surfactants and detergents》2021,24(1):3-13
Two generations of novel linear-dendritic carboxylate surfactants C18-G1-(COONa)2 and C18-G2-(COONa)4 have been synthesized by the divergent method and their structures are characterized by 1H Nuclear Magnetic Resonance and Infrared analysis. The electrical conductivity measurement is used to measure the Krafft temperatures of C18-G1-(COONa)2 and C18-G2-(COONa)4, which are much smaller than those of the corresponding conventional surfactant sodium stearate. The markedly enhanced solubility of two linear-dendritic surfactants is ascribed to the high hydrophilicity of surfactant headgroups induced by the carboxylate and ester groups. The critical micelle concentration (CMC) values obtained from both the electrical conductivity and surface tension measurements indicate that the micellizations of linear-dendritic surfactants become favorable with the increase in the number of the surfactant headgroup. However, the surface activity parameters including the surface tension at the CMC, maximum surface excess, and minimum surface area reveal that C18-G1-(COONa)2 exhibits greater efficiency in absorbing at the air/water interface compared to C18-G2-(COONa)4, owing to their different steric repulsions of the surfactant headgroups. In addition, C18-G1-(COONa)2 and C18-G2-(COONa)4 have higher emulsifying ability than the conventional surfactants sodium stearate and sodium octadecyl sulfate. 相似文献
53.
本文通过研究目前汽车烤漆房的实际运行情况,提出了一种汽车烤漆房喷漆自动控制系统,阐述了系统喷漆装置的构成、配合与运行原理,并构成了实际试验系统。 相似文献
54.
55.
针对口罩阻挡新冠病毒的检测方法问题,在讨论病毒特征、口罩作用基础上,对目前国内普遍采用的细菌过滤效率(BFE)和非油性颗粒过滤效率(PFE)检测方法进行了对比研究.结果表明,颗粒过滤效率与细菌过滤效率没有相关性,用颗粒过滤效率替代细菌过滤效率的风险较大. 相似文献
56.
Chung-Kuan Wu Ji-Fan Lin Tzong-Shyuan Lee Yu Ru Kou Der-Cherng Tarng 《International journal of molecular sciences》2021,22(7)
TRPA1, a nonselective cation channel, is expressed in sensory afferent that innervates peripheral targets. Neuronal TRPA1 can promote tissue repair, remove harmful stimuli and induce protective responses via the release of neuropeptides after the activation of the channel by chemical, exogenous, or endogenous irritants in the injured tissue. However, chronic inflammation after repeated noxious stimuli may result in the development of several diseases. In addition to sensory neurons, TRPA1, activated by inflammatory agents from some non-neuronal cells in the injured area or disease, might promote or protect disease progression. Therefore, TRPA1 works as a molecular sentinel of tissue damage or as an inflammation gatekeeper. Most kidney damage cases are associated with inflammation. In this review, we summarised the role of TRPA1 in neurogenic or non-neurogenic inflammation and in kidney disease, especially the non-neuronal TRPA1. In in vivo animal studies, TRPA1 prevented sepsis-induced or Ang-II-induced and ischemia-reperfusion renal injury by maintaining mitochondrial haemostasis or via the downregulation of macrophage-mediated inflammation, respectively. Renal tubular epithelial TRPA1 acts as an oxidative stress sensor to mediate hypoxia–reoxygenation injury in vitro and ischaemia–reperfusion-induced kidney injury in vivo through MAPKs/NF-kB signalling. Acute kidney injury (AKI) patients with high renal tubular TRPA1 expression had low complete renal function recovery. In renal disease, TPRA1 plays different roles in different cell types accordingly. These findings depict the important role of TRPA1 and warrant further investigation. 相似文献
57.
1 INTRODUCTIONOrganic intercalatedlayeredsolidshavebeenstudiedbyscientistsindifferentfieldsformanyyearsbecauseoftheirnew physicalandchemicalpropertiessuchaselectricalproperties[1] ,mechanicalproper ties ,thermalbehavior[2 ] ,surfaceandinterfacialproperties[3] .Graphiteoxide (GO)hasbeenstudiedformany years ,itsstructuralmodel[4 6 ] ,formationprocessandkinetics[7,8] havebeenstudiedindetail.IthasbeenreportedthatGOpossessesC OHande poxidefunctionalgroups[9] whichmakegraphiteox ideeasilyabs… 相似文献
58.
59.
Margarida Taborda Duarte H. Y. Liu S. Q. Kou P. -A. Lindqvist K. Miskovsky 《Journal of Materials Engineering and Performance》2005,14(1):104-111
The importance of the microstructural parameters in rock mechanical behavior has been investigated by several authors. Moreover,
the Weibull statistical model has been used to characterize the heterogeneity of several materials on the basis of the concept
that the microscopic defects within the material determine their mechanical strength. The modeling of different rocks is a
topic that is fundamental for the prediction of rock fragmentation. In this article, the analysis of rock microstructure is
performed using the microstructural modeling approach, which consists of the simplification, quantification, and modeling
of the main properties of rock microstructure. The grain size, grain shape, and microcracks are modeled by means of statistical
density functions, namely, Cauchy, chi-squared, exponential, extreme value, gamma, Laplace, normal, uniform, and Weibull.
It is found that the Weibull distribution is the most appropriate statistical model of the grain size and grain shape, when
compared with the other eight statistical models. Regarding microcracks, the results show that the gamma distribution is the
most appropriate model. The Weibull and gamma distributions are then used to analyze the heterogeneity of the microstructure.
This is done by comparison of the statistical models of each microstructural property evaluated in several thin sections of
the same rock. It is found that with respect to grain size and grain shape, the rock is homogeneous, while the size distribution
of the microcracks shows a clear trend toward less homogeneity. The microstructural modeling approach is important for modeling,
characterizing, and analyzing the microstructure of rock material. Among other applications, it can be used to explain differences
in the mechanical behavior obtained in testing several specimens. 相似文献
60.
本文提出一种新的Kossel定向方法。它只要求测出透射Kossel花样上的三个Kossel线交点之间的距离就能定向,从而减少了误差的来源,提高了定向精度。通常的透射Kossel照片定向误差为σ=±0.3° 相似文献