Miniaturized devices

Electrochemistry is the basis of many important and modem applications and scientific developments such as nanoscale machining (fabrication of miniature devices with three dimensional control in the nanometer scale), electrochemistry at the atomic scale, scanning tunneling microscopy, transformation of energy in biological cells, selective electrodes for the determination of ions, and new kinds of electrochemical cells, batteries and fuel cells. 

Lowe, H., Ehreeld, W, Schiewe, J., Micro-electroforming of miniaturized devices for chemical applications, in ScHULTZE, W, Osaka, T., Datta, M. (Eds.), Electrochemical Microsystem Technologies, pp. 245-268, Taylor Erands, London (2002). 

We can already deduce that, due to the characteristics of the active medium, compact and miniaturized devices are attainable for semiconductor lasers. This fact, together with the possibility of custom-designed systems, constitutes a real advantage from the viewpoint of integrated opto-electronic devices. In the field of spectroscopy, they are commonly used as pumping sources for other types of solid state lasers, as will be seen later. 

The silicon substrate constitutes a very interesting support for facilitating the integration in microelectronic devices. The electrochemical and electroanalytical fields can gain remarkable benefits from the silicon-based miniaturization devices, especially if arrays of metal electrodes can be fabricated. An understanding of the electrochemical properties of CNTs directly attached to silicon is thus essential for their potential application in developing silicon-based electrochemical or (bio)electrochemical... 

Further, the development of miniaturized devices for the generation of power and/ or heat is discussed here as it represents an emerging field of application of catalytic combustion. Due to the presence of the catalytic phase, the microcombustors have the potential to operate at significantly lower temperatures and higher surface-to-volume ratios than non-catalytic microcombustors. This makes them a viable solution for the development of miniaturized power devices as an alternative to batteries. 

Indeed, substantial progress in the application of DNA as a template for the bottom-up construction of metallic NPs or nanowire circuitry, and the assembly of nanoscale miniaturized devices, was demonstrated in the past decade.90... 

Figure 22-23 Electrospray quadrupole mass spectrum of acidified bovine cytochrome c showing peaks from species with different numbers of protons, MHfJ+. [From T. Wachs and J. Henion, Electrospray Device tor Coupling Microscale Separations and Other Miniaturized Devices with Electrospray Mass Spectrometry." Anal. Chem. 200T, 73, 632.]...

Three types of mixer are recognized, plus a miniature mixer which would provide just enough compound for a curemeter test and one sheet. Mixers types A] and A2 and the miniature device have non-interlocking (tangential) rotors whilst type B has interlocking rotors. Dimensions of the larger mixers are specified fairly precisely, including new and worn rotor clearances, and they are required to have temperature control, a system to record power or torque and a timer. The miniature mixer is only specified in terms of capacity, rotor speed and friction ratio but is required to control of temperature, indication of power and a timer. 

Miniature alkaline cells are small, bullon-shaped cells which use alkaline NaOH or KOH electrolyte and generally have zinc anodes, bin may have a variety of cathode materials. They are used in watches, calculators, cameras, hearing aids, and other miniature devices. 

The most significant reported absorbance-based miniaturized devices are detailed next. 

Micromixing technologies have only recently been applied to the design of miniaturized devices for chemical applications, so called microreactors. The main components of such microreactors are mixers and heat exchangers. 

Inherent Process Restrictions in Miniaturized Devices and Their Potential Solutions... 

Jones et al. [116] presented an integrated and miniaturized device for methanol steam reforming consisting of two evaporators/pre-heaters, a reformer and a combustor with a total volume of < 0.2 cm3 for a power range between 50 and... 

Integration of various components of a miniaturized device requires methods for bonding materials to substrates [64]. The most commonly used technologies for joining glass and silicon components include ... 

Several review articles describing miniaturized devices for fluid handling have been published that give excellent and detailed overviews of the state of the art [3,4]. Here, some examples of microfabricated valves and pumps will be given to illustrate the possibilities of silicon microtechnology. 

As mentioned in Chapter 1, the present state of CMP is the result of the semiconductor industry s needs to fabricate multilevel interconnections for increasingly complex, dense, and miniaturized devices and circuits. This need is related to improving the performance while adding more devices, functions, etc. to a circuit and chip. This chapter, therefore, discusses the impact of advanced metallization schemes on the performance and cost issues of the ICs. Our discussions start with the impact of reducing feature sizes on performance and the need of various schemes to counter the adverse effect of device shrinkage on the performance of interconnections. An impact of continued device shrinkage on circuit delay is discussed. Then the need of low resistivity metal, low dielectric constant ILD, and planarized surfaces is established leading to the discussion of CMP. Finally various planarization techniques are compared to show why CMP is the process that will satisfy the planarity requirements of the future. 

In addition to the design of the solid-gas contactor device, the yield of a desulfurization process directly depends on the physicochemical properties of the used adsorbent crystallite size of the active phase, specific surface area, and porous texture. In the case of a microporous membrane, if the gas flow is forced across the microporosity, it can be expected that the retention will be highly efficient. In return, the low amount of adsorbent restricts the potential applications to the elimination of traces in high-purity gas or to the design of integrated filters for miniaturized devices like micro fuel cells. 

Other types of multifunctional miniaturized devices using ceramic hollow fibers can and should be developed in the near future, as suggested by Figure 25.32, which illustrates the case of coupling separation and photocatalysis. 

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