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排序方式: 共有10000条查询结果,搜索用时 9 毫秒
961.
F. -U. Gast P. S. Dittrich P. Schwille M. Weigel M. Mertig J. Opitz U. Queitsch S. Diez B. Lincoln F. Wottawah S. Schinkinger J. Guck J. Käs J. Smolinski K. Salchert C. Werner C. Duschl M. S. Jäger K. Uhlig P. Geggier S. Howitz 《Microfluidics and nanofluidics》2006,2(1):21-36
We describe a novel microfluidic perfusion system for high-resolution microscopes. Its modular design allows pre-coating of
the coverslip surface with reagents, biomolecules, or cells. A poly(dimethylsiloxane) (PDMS) layer is cast in a special molding
station, using masters made by photolithography and dry etching of silicon or by photoresist patterning on glass or silicon.
This channel system can be reused while the coverslip is exchanged between experiments. As normal fluidic connectors are used,
the link to external, computer-programmable syringe pumps is standardized and various fluidic channel networks can be used
in the same setup. The system can house hydrogel microvalves and microelectrodes close to the imaging area to control the
influx of reaction partners. We present a range of applications, including single-molecule analysis by fluorescence correlation
spectroscopy (FCS), manipulation of single molecules for nanostructuring by hydrodynamic flow fields or the action of motor
proteins, generation of concentration gradients, trapping and stretching of live cells using optical fibers precisely mounted
in the PDMS layer, and the integration of microelectrodes for actuation and sensing. 相似文献
962.
A risk approach to the management of boiler tube thinning 总被引:1,自引:0,他引:1
A large set of industrial thickness inspection data covering four boiler units of a power station over a period of five years was made available to the authors. The measurements were made in regions of the boiler where corrosion/erosion was the major cause of failure of the boiler tubes. There were over 40,000 separately measured data points in the data and all were collected with some care and expense.In the development of maintenance strategies for equipment, this type of data is typical of the data that must be collected and assessed. This data thus represents an opportunity to evaluate the ability to generate a useful risk approach to the management of the tubing.An important example of a risk-based approach is the American Petroleum Institute (API) Risk Based Inspection (“RBI”), API 581. A variety of problems were encountered applying this to boiler tubes. The problems include irrelevant API 581 corrosion rate tables, lack of information on how to analyse inspection data, difficulty of dealing with multiple inspection categories and lack of suitable direction for programming inspection intervals. 相似文献
963.
A mathematical model to simulate the performance of anaerobic ponds was developed incorporating both settling of particulate components and the biological anaerobic digestion process. The biological activity includes solubilization of particulate organic matter; methanogenesis and the sulphate reduction process. The model considers that an anaerobic pond comprises a series of equal size columns. Each column has three compartments viz. liquid layer, active sediment layer and inert sediment layer. The existence of organic matter and sulphate removal mechanisms both in the bulk as well as sediment layer of the ponds and the exchange of the soluble components between the layers has been included in the model. The model was transferred to a computer program using VisSim Basic software. The model was verified by comparing simulated results with full-scale as well as with laboratory-scale anaerobic pond performance data. A good agreement between the simulated and the observed pond performance was achieved. 相似文献
964.
Infiltration systems are frequently used as an option to manage urban storm drainage. By reducing flows and volumes in downstream sewers or in surface waters, they decrease the overflows and make it possible to recharge groundwater. They come in various forms with different uses; therefore, their performance is diverse and integrates multiple aspects. Consequently, a multicriteria approach was developed in order to quantify the performance of these systems and to help in decision making problems. For that purpose, a list of performance indicators integrating technical, economical, environmental and social aspects was developed. The performances were defined with the help of a working group composed of engineers from different technical or strategic departments from Greater Lyon and researchers from different fields. The paper presents the last version of the performance indicators tested according to a set of quality requirements: availability of data, relevance, fidelity, precision, sensitivity/robustness. This critical review of the set of indicators has led us to redefine a certain number of indicators, identify numerous biases and allow putting forward general instructions for criterion or indicator construction. The last phase is to propose multicriteria decision aid methods; a procedure using ELECTRE methods should be used. 相似文献
965.
This article deals with directive 94/9/EC which applies to products that exist in an oil and gas company under the responsibility of the electrical, instrumentation engineers. Directive 1999/92/EC applies to users and defines the minimum requirements for improving the safety and health protection of workers, is under the responsibility of the safety division (HSE). These new ATEX directives are called the "new approach," which aims to ensure free movement of the products to which it applies by removing barriers to trade. It also aims to improve the safety of products and users. The main advantage of the new approach is that it is no longer necessary to make an adaptation to technical developments in order to keep up with technical developments 相似文献
966.
A. V. Pavlenko V. P. Grinchenkov A. A. Gummel I. A. Pavlenko E. Kallenbakh 《Russian Electrical Engineering》2007,78(4):190-197
The design principals of fast-operating electromagnetic drives with prescribed dynamic performances are examined. The represented procedure permits the command parameters to be to determined with the guaranteed prescribed parameters of the drive. 相似文献
967.
M. Djaeni P. Bartels J. Sanders G. van Straten A. J. B. van Boxtel 《Drying Technology》2007,25(6):1053-1067
This work discusses the potential of three multistage zeolite drying systems (counter-, co-, and cross-current) with a varying number of stages. The evaluation showed that for 2-4 stages with heat recovery the efficiency of the systems ranges between 80 and 90%. Additionally, by introducing a compressor, the latent heat in the exhaust air from the regenerator is recovered and used to heat the inlet air for an additional drying stage. As a result, for the counter-current drying system and compressor pressure 1.5-2 bar, a maximum energy efficiency of 120% is achieved, which results in halving the energy consumption compared to conventional drying systems. 相似文献
968.
V. N. Kostyukov A. P. Naumenko V. A. Starikov A. A. Sinitsyn A. M. Volkov A. S. Rubanenko A. V. Rykin O. V. Kuznetsov 《Metallurgist》2007,51(11-12):596-604
Introduction of the BER? KOMPAKS® automated system at the Vyksa Metallurgical Plant to safely and efficiently manage the operation of the plant’s equipment has allowed the facility to begin operating that equipment based on real-time evaluations of its actual physical condition. Introduction of the new system has also allowed better coordination of repair-scheduling with ongoing production operations, significantly improved the reliability and readiness of the equipment for operation at 100% capacity, completely eliminated the human factor from the process of monitoring the condition of equipment, and made it possible to check the quality and timeliness of equipment maintenance and repair work so as to ensure safe, efficient operation of the entire production complex. 相似文献
969.
N. P. Matveiko P. G. Kramtsov G. E. Slepnev 《Journal of Engineering Physics and Thermophysics》1987,52(5):586-590
Electrodes with different composition were prepared by the method of pressing followed by sintering of the graphite and vanadium disilicide powders, and their electrochemical and corrosion properties in water solutions of electrolytes were studied.Translated from Inzhenerno-Fizicheskii Zhuraal, Vol. 52, No. 5, pp. 802–707, May, 1987. 相似文献
970.
Alkali-metal carbonate salts meet the requirements for high-temperature solar central receiver systems, but because of their corrosiveness they present special problems in the design of storage tanks. In order to reduce corrosion and temperature sufficiently to retain strength in the storage containing wall, internal and thermal insulation is required. We present design options and operation criteria for sensible-heat, molten-salt storage with internal insulation. 相似文献