Cell spacer

Nonuniform cell thickness can affect a quantitative analysis. This is potentially a problem, especially in infrared spectrometry, where cell spacers are used. Air bubbles can affect the pathlength and stray tight, and it is important to eliminate these bubbles, again especially in the infrared cells. 

LCD spacer has two kinds of usage. Spacer particles used in a display portion is called cell spacer or sinply spacer . Another use pf spacer particle is for an epoxy-sealant which encloses liquid crystals in a LCD cell as shown in Figure 8-1. 

At present, most of the cell spacer used for LCD are the resin spacer or the silica spacer. Among them, the resin spacer is more popular than the silica spacer. The reason for this is... 

Since the individual cells of a spin-dependent liquid-electrolyte reserve battery are generally annular in shape and are filled by centrifugal force, the periphery of the cell must be sealed to keep electrolyte from leaking out. This sealing is typically accomplished by a plastic barrier formed around the outside of the electrode-spacer stack. For lead/fluoboric acid/lead dioxide batteries, this barrier is formed by fish paper (a dense, impervious paper) coated with polyethylene that melts at a relatively low temperature (similar to that used on milk cartons). Cell spacers are punched from the coated fish paper and placed between the electrodes. The stack is then clamped together and heated in an oven at a temperature sufficient to fuse the polyethylene, which then acts as an adhesive and sealer between the electrodes. 

An expandable anode involves compression of the anode stmcture using cHps during cell assembly so as not to damage the diaphragm already deposited on the cathode (Eig. 3a). When the cathode is in position on the anode base, 3-mm diameter spacers are placed over the cathode and the cHps removed from the anode. The spring-actuated anode surfaces then move outward to bear on the spacers, creating a controlled 3-mm gap between anode and cathode (Eig. 3b). This design has also been appHed to cells for the production of sodium chlorate (22). 

The membranes are supported and kept apart by feed spacers. A typical cell gap is 0.5-2 mm. The spacer also helps control solution distribution and enhances mass transfer to the membrane. Given that an industrial stack may have up to 500 cell pairs, assuring uniform flow distribution is a major design requirement. 

FIG. 22-60 Expl oded view of a sheet-feed ED stack. Manifolds are built into the membranes and spacers as the practical way to maintain a narrow cell gap. Coutiesy Elsevier.)... 

Electrochemical cells are assembled in the glove-box. The cell is a 2320-type coin cell (23 mm OD and 2.0 mm thickness) as schematically shown in Fig. 5. The cell includes the electrolyte, the cell cap and can which are stainless steel, a polypropylene gasket used to seal the cell, the two electrodes, the separator between the electrodes, as well as a stainless spacer and a mild steel disc spring which are used to increase the pressure on the electrodes. Once the cell is assembled in the right order, the cell is sealed by a pressure crimper inside the glove-box. 

Neoprene gasket Cell window Lead spacer Cell window Neoprene gasket... 

In the older battery literature the term separator is frequently used very loosely, to include all nonmetallic solid components between the electrodes, such as supporting structures for active materials (tubes, gauntlets, glass mats), spacers, and separators in a narrow sense. In this section, only the last of these, the indispensable separating components in secondary cells, will be termed separators , distinguished from the others by their microscopically small pores, i.e., with a mean diameter significantly below 0.1 mm. 

Fig. 12a,b. The sensorgrams for the binding of the antibody dendrimer (a) or IgG (b) to the anionic porphyrin immobilized onto the surface of the sensor chip. Phosphate borate buffer (0.1 M, pH 9.0) was used. TCPP was immobilized via hexamethylenediamine spacer onto the sensor chip and then a solution of IgG or the dendrimer was injected to the flow cell. After 60 s from the injection of the antibody solutions, flow ceU was filled with buffer... 

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