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91.
Independent design of robust partially decentralized controllers 总被引:1,自引:0,他引:1
An independent design method for robust partially decentralized controllers is developed. In the proposed design method, the partially decentralized control system is first expanded to the nonsquare decentralized structure. Using the Internal Model Control parametrization, the independent design procedure for robust nonsquare decentralized controllers can then be applied directly to the expanded system. Two examples, including a nonlinear stirred mixing tank, are used to illustrate the developed design method and a comparison to a decentralized controller is made. 相似文献
92.
Yali Zhang Teck Neng Wong Chun Yang Kim Tiow Ooi 《International Journal of Engineering Science》2005,43(19-20):1450-1463
The electrokinetic flow through star-point family microchannels is studied. Mathematical solutions using a semi-analytical approach are employed to model the steady, fully developed electroosmotic flow in the closed-end star point family microchannels. The model can be extended to other irregular shape channels. The effects of sharp corners, electrolyte concentration and packed capillary radius, R0 are analyzed. Comparisons of the flow characteristics and induced pressure gradient inside and outside of the packed capillaries are presented. 相似文献
93.
Natassia Goode Paul M. Salmon Michael G. Lenné Peter Hillard 《Accident; analysis and prevention》2014
Injuries resulting from manual handling tasks represent an on-going problem for the transport and storage industry. This article describes an application of a systems theory-based approach, Rasmussen's (1997. Safety Science 27, 183), risk management framework, to the analysis of the factors influencing safety during manual handling activities in a freight handling organisation. Observations of manual handling activities, cognitive decision method interviews with workers (n = 27) and interviews with managers (n = 35) were used to gather information about three manual handling activities. Hierarchical task analysis and thematic analysis were used to identify potential risk factors and performance shaping factors across the levels of Rasmussen's framework. These different data sources were then integrated using Rasmussen's Accimap technique to provide an overall analysis of the factors influencing safety during manual handling activities in this context. The findings demonstrate how a systems theory-based approach can be applied to this domain, and suggest that policy-orientated, rather than worker-orientated, changes are required to prevent future manual handling injuries. 相似文献
94.
Silicon/silicon carbide (Si/SiC) core–shell nanowires grown on quartz substrates by hot-wire chemical vapor deposition were studied. Nickel was used as a catalyst to induce the growth of these core–shell nanowires followed by the vapor–solid–solid growth mechanism. The nanowires were grown by varying substrate-to-filament distance; ds-f from 1.9 to 3.1 cm with an interval of 0.4 cm. Lower ds-f produced a high density of straight core–shell nanowires. A highly crystalline single crystal Si core of the nanowires was produced at lower ds-f as well. Presence of Si and SiC nano-crystallites embedded within an amorphous matrix in the shell of the nanowires exhibited a high intensity of photoluminescence emission spectra from 600 to 1000 nm. The effects of the ds-f on the structural and optical properties of the nanowires are discussed. 相似文献
95.
AFM Imaging of Molecular Spin‐State Changes through Quantitative Thermomechanical Measurements 下载免费PDF全文
96.
A New In Situ Microscopy Approach to Study the Degradation and Failure Mechanisms of Time‐Dependent Dielectric Breakdown: Set‐Up and Opportunities 下载免费PDF全文
Zhongquan Liao Martin Gall Kong Boon Yeap Christoph Sander Oliver Aubel Uwe Mühle Jürgen Gluch Sven Niese Yvonne Standke Rüdiger Rosenkranz Markus Löffler Norman Vogel Armand Beyer Hans‐Jürgen Engelmann Peter Guttmann Gerd Schneider Ehrenfried Zschech 《Advanced Engineering Materials》2014,16(5):486-493
97.
Cancer metastasis involves the dissemination of cancer cells from the primary tumour site and is responsible for the majority of solid tumour-related mortality. Screening of anti-metastasis drugs often includes functional assays that examine cancer cell invasion inside a three-dimensional hydrogel that mimics the extracellular matrix (ECM). Here, we built a mechanically tuneable collagen hydrogel model to recapitulate cancer spreading into heterogeneous tumour stroma and monitored the three-dimensional invasion of highly malignant breast cancer cells, MDA-MB-231. Migration assays were carried out in the presence and the absence of drugs affecting four typical molecular mechanisms involved in cell migration, as well as under five ECMs with different biophysical properties. Strikingly, the effects of the drugs were observed to vary strongly with matrix mechanics and microarchitecture, despite the little dependence of the inherent cancer cell migration on the ECM condition. Specifically, cytoskeletal contractility-targeting drugs reduced migration speed in sparse gels, whereas migration in dense gels was retarded effectively by inhibiting proteolysis. The results corroborate the ability of cancer cells to switch their multiple invasion mechanisms depending on ECM condition, thus suggesting the importance of factoring in the biophysical properties of the ECM in anti-metastasis drug screenings. 相似文献
98.
Rapid Quantification of Live Cell Receptors Using Bioluminescence in a Flow‐Based Microfluidic Device 下载免费PDF全文
Cheong Fook Cheong Hiroaki Hirata Abdur Rub Abdur Rahman Chwee Teck Lim 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(8):943-951
The number of receptors expressed by cells plays an important role in controlling cell signaling events, thus determining its behaviour, state and fate. Current methods of quantifying receptors on cells are either laborious or do not maintain the cells in their native form. Here, a method integrating highly sensitive bioluminescence, high precision microfluidics and small footprint of lensfree optics is developed to quantify cell surface receptors. This method is safe to use, less laborious, and faster than the conventional radiolabelling and near field scanning methods. It is also more sensitive than fluorescence based assays and is ideal for high throughput screening. In quantifying β1 adrenergic receptors expressed on the surface of H9c2 cardiomyocytes, this method yields receptor numbers from 3.12 × 105 to 9.36 × 105 receptors/cell which are comparable with current methods. This can serve as a very good platform for rapid quantification of receptor numbers in ligand/drug binding and receptor characterization studies, which is an important part of pharmaceutical and biological research. 相似文献
99.
Vopsaroiu M Weaver PM Cain MG Reece M Chong KB 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(9):1867-1873
Time- and temperature-dependent effects are critical for the operation of non-volatile memories based on ferroelectrics. In this paper, we assume a domain nucleation process of the polarization reversal and we discuss the polarization dynamics in the framework of a non-equilibrium statistical model. This approach yields analytical expressions which can be used to explain a wide range of time- and temperature-dependent effects in ferroelectrics. Domain wall velocity derived in this work is consistent with a domain wall creep behavior in ferroelectrics. In the limiting case of para-electric equilibrium, the model yields the well-known Curie law. We also present experimental P-E loops data obtained for soft ferroelectrics at various temperatures. The experimental coercive fields at various temperatures are well predicted by the coercive field formula derived in our theory. 相似文献
100.
Consistent data regarding the flammability limits of homogeneous mixtures of hydrogen gas in air at atmospheric pressure are presented for various temperatures extending down to ?130 °C. The retardation of the combustion of lean homogeneous mixtures of hydrogen and air due to the homogeneous mixing of inerts such as CO2, N2 and He is also considered. Moreover, the enhancement of the flammability limits of fuel mixtures involving CO, CH4, C3H8 and C2H4 in air due to the presence of some hydrogen is also presented. Guidelines are then suggested for predicting the role of the presence of hydrogen in the fuel-air mixtures over a wide range of concentrations and temperatures. 相似文献