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81.
Drift is a common phenomenon in active sensors and, if left untreated, is generally the limiting factor in their performance. It is shown that drift and spread in sensor characteristics are tightly interwoven due to finite sensitivity to biasing parameters. Modern treatments of drift are dynamical under operating conditions, notably so chopping, the sensitivity variation method and the recently introduced van Putten-method. These methods differ in regards to drift-dependence on biasing. In their application to silicon flow sensors, the first two reduce but do not eliminate drift. The geometric van Putten-method leaves biasing invariant, which eliminates drift and obtains uniform sensor-characteristics leaving drift-free operation. 相似文献
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Fundamentals of particle–particle interaction are of great interest in agglomeration processes. Particle adhesion depends on dispersive forces (van der Waals force), local chemical bindings, Coulomb force and capillary attractions. Additionally, surface properties like roughness, adsorption layers and surface chemistry strongly affect adhesion forces. van der Waals interactions are poorly understood because popular ab initio force calculations for molecules like density functional theory (DFT) often do not lead to proper results. van der Waals forces are difficult to measure directly. We present direct measurements of particle–particle and particle–surface interactions in the gas phase carried out with an atomic force microscope (AFM). Special emphasis is given to a proper statistical treatment of the data. For modelling of particle adhesion, we use computer-assisted empirical potential methods. Parameters like adsorbed water and surface roughness are considered. We extract parameters for weak interactions from the Lifshitz theory and gas adsorption data. Adsorbing molecules can be used as probes to measure dispersive forces. Studying surface and particle properties combined with computer-assisted modelling is a basic requisite to reach the aim of predicting particle–particle interactions in industrial processes. 相似文献
84.
S. C. Zhou * O. L. Shuai T. T. Wong * T. P. Leung * ** This Project is Supported Partly by National Natural Science Foundation of China 《国际设备工程与管理》1997,(4)
ANovelParsimoniousNeurofuzzyModelAppliedtoRailwayCariageSystemIdentificationandFaultDiagnosisS.C.Zhou,O.L.Shuai+,T.T.Wong?.. 相似文献
85.
A. Ghorbanpour Arani R. Rahmani A. Arefmanesh S. Golabi 《Journal of Mechanical Science and Technology》2008,22(3):429-439
The torsional and axially compressed buckling of an individual embedded multi-walled carbon nanotube (MWNTs) subjected to
an internal and/or external radial pressure was investigated in this study. The emphasis is placed on new physical phenomena
which are due to both the small length scale and the surrounding elastic medium. Multiwall carbon nanotubes which are considered
in this study are classified into three categories based on the radius to thickness ratio, namely, thin, thick, and almost
solid. Explicit formulas are derived for the van der Waals (vdW) interaction between any two layers of an MWNT based on the
continuum cylindrical shell model. In most of the previous studies, the vdW interaction between two adjacent layers was considered
only and the vdW interaction among other layers was neglected. Moreover, in these works, the vdW interaction coefficient was
treated as a constant that was independent of the radii of the tubes. However, in the present model the vdW interaction coefficients
are considered to be dependent on the change of interlayer spacing and the radii of the tubes. The effect of the small length
scale is also considered in the present formulation. The results show that there is a unique buckling mode (m,n) corresponding to the critical shear stress. This result is obviously different from what is expected for the pure axially
compressed buckling of an individual multi-walled carbon nanotube. 相似文献
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本文通过计算机的模拟方法,检测安装在汽车后扰流板模型的外流场的阻力,通过计算机模拟,对汽车后扰流板的安装位置、安装形状及安装角度进行了科学的分析。科学的安装汽车后扰流板,不仅能够降低气动升力,还可以有效地减少汽车所受气动阻力,降低汽车油耗,对提高汽车气动特性有很大的工程指导性。 相似文献
88.
Epitaxial Growth of Molecular Crystals on van der Waals Substrates for High‐Performance Organic Electronics 下载免费PDF全文
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