Special Geometrical Design

Improved Carrier Extraction by Intercalating Membranes. With light trapping, the condition for good extraction of electrons and holes requiring Le,h l, is also relaxed, since a smaller thickness of the solar cell is possible. For low mobility organic materials, this condition is still a problem. It ensures that electrons and holes generated in the absorber reach the membrane within their recombination lifetime. They can then pass into the external circuit. The distance of the membranes, however, is not limited by the thickness l of the absorber, as can be seen in Fig. 4.11, and can be made arbitrarily short. 

Electrons and holes are not mobile at all in the dye. Electrons and holes can nevertheless tunnel into their membranes, since the dye layer is only a mono-molecular coverage of the TiC 2 particles immersed in the electrolyte. Sufficient absorption is achieved by forming a network of dye-covered TiC 2 particles, which is about 1000 particles thick. Close contact between the p-membrane and the dye is achieved by a liquid electrolyte, containing a redox couple for charge transport, which penetrates the network of particles. This structure has a disadvantage, originating from the bad transport properties of the dye an interface is formed between n- and p-membranes with an area 

As a result of light trapping and intercalation, thin film solar cells can be made of a thickness /, which apparently violate the condition Le,h l 1 /a. Even with light trapping, the thickness l must be of the order of the penetration depth /a of the light. The diffusion length, on the other hand, can be arbitrarily small, if caused by a small diffusion coefficient. The recombination lifetime should always be as large as possible and should approach the radiative lifetime. 

So far, due to the boundary conditions introduced by the technology for preparing these devices, only n = 2 (tandem cells) and tii = 3 (triple cells) seem to be of relevance [41,42], 

Seeger Semiconductor Physics (Springer Verlag, Berlin 1991) 

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In column RPC (Figure 14), there is no vapor space (75). The stationary phase is placed in a closed circular chamber (column), and the flow is accelerated linearly by centrifugal force. The volume of stationary phase remains constant along the separation distance, hence the name column RPC. Since it is a closed system, there is no vapor space and any stationary phase of fine particle size may be used with or without binder. The rotating planar column has a special geometric design, which may be described by the function ... 

Compared to conventional molds, the size of the inserts and injection molded parts are the real challenge for the designer in micro mold making. The durability of the insert in the injection molding compound after removal from the mold and the subsequent use must be taken into consideration. This can be achieved by constructive measures with special geometric shapes, but also by surface treatments of the inserts. 

Examined the relationship between highway accident potential and geometric design elements, based on existing research literature and on special research projects commissioned as part of the study. 

TRB Special Report 214 devoted a full chapter discussing the relationships of safety and geometric design. This was also the subject of an NCHRP study that was reported as NCHRP Report 374 Effects of... 

Overlaid lumber is a composite of lumber and phenolic resin-treated kraft paper. Similar paper overlays are applied to veneer, plywood, fiberboard, and particleboard. Paper honeycomb cores also are made from phenolic resin-treated kraft paper, which is formed into a honeycomb of different geometrical designs, such as figure eight or hexagonal, in special... 

In both cases special probes were designed and manufactured For the first ease a special probe which fits geometrically exactly to the contour of the turbine blade and in the other case a combined transducer system was developed which enables a continuous measurement of... 

Cell geometry, such as tab/terminal positioning and battery configuration, strongly influence primary current distribution. The monopolar constmction is most common. Several electrodes of the same polarity may be connected in parallel to increase capacity. The current production concentrates near the tab connections unless special care is exercised in designing the current collector. Bipolar constmction, wherein the terminal or collector of one cell serves as the anode and cathode of the next cell in pile formation, leads to gready improved uniformity of current distribution. Several representations are available to calculate the current distribution across the geometric electrode surface (46—50). 

Raman probes constructed from fused silica optical fibers have gained much attention recently. Typically, low-OH content fibers are utilized to reduce the fiber fluorescence. The probe design also includes filters at the distal end to suppress the fused silica Raman signal from the excitation fiber and suppress the elastically scattered fight entering the collection fibers.25 Commercial probes are now available and they offer ruggedness and easy access to samples with various special or geometrical constraints. 

A special typed software (MicroSim) was designed to allow the user to analyze, calculate, predict and optimize experimental runs in the toolkit. That means that the user is not to be required to do any modeling in the sense of formulating mathematical equations or representing geometric configurations. In contrast to CFD simulations, the time required for simulation of a micro reaction process with its peripherals is in the range of a few minutes. Furthermore, MicroSim mns on standard PCs. 

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