Separators scanning electron micrographs

The processes for manufacturing microporous membranes can be broadly divided into wet processes and dry processes. Both processes usually employ one or more orientation steps to impart porosity and/or increase tensile strength. Figure 2 shows scanning electron micrographs of surfaces of separators made by each process. 

More stringent requirements, especially with regard to separation efficiency and reproducibihty in preparative planar chromatography also, led to increased application of precoated plates in this field. Figure 3.3 shows a scanning electron micrograph of a cross section through a PLC plate silica gel. 

FIG. 3. Chromosome arms begin to separate in pro metaphase. Scanning electron micrographs of human chromosomes isolated from cells in prophase (A), prometaphase (B), metaphase (C) and early anaphase (insert in C). Size bar, 1 /tm. Reprinted with permission from Sumner (1991). 

Figure 13.6. Effects of stress concentration on breakability. Scanning electron micrographs (top frames) showing breaks of anchored silicon beams etched with (a) plasma, (b) KOH and isopropyl alcohol, and (c) KOH and optical micrographs (bottom frames) of printing results that demonstrate the relative ease of breakability, or the ability for a stamp to separate elements from the anchoring structures in each system. (Reprinted with permission from Ref. 54. Copyright 2007 American Institute of Physics.)...

A cross-sectional view of a C. digitata seed is shown in a scanning electron micrograph (SEMT in Figure 1. The section was treated with hexane before being sputter-coated (12) and is morphologically identical to a similar view of C. pepo (12). The seed coat comprises the somewhat thin outer boundary of TRe section and the remainder is composed of two cotyledons separated by the first "true" leaves of the embryo. 

For efficient separation, porous inorganic membranes need to be crack-free and uniform in pore size. An important reason for the increasing acceptance of ceramic membranes introduced in recent years is the consistent quality as exemplified in a scanning electron micrograph of the surface of a 0.2 micron pore diameter alumina membrane (Figure 3.3). 

Figure 4. Scanning electron micrographs of the surface of single layer Celgard separators used in lithium batteries (a) 2400 (PP), (b) 2500 (PP), and (c) 2730 (PE).

Figure 5. Scanning electron micrographs of Celgard 2325 (PP/PE/PP) separator used in lithium-ion batteries (a) surface SEM and (b) cross-section SEM.

Fig.18a-b. Scanning electron micrographs on cryo fractured surfaces of a macroporous epoxy prepared with 6 wt % hexane via the Cl PS technique showing a narrow size distribution b macroporous epoxy prepared with 7.5 wt % hexane via the CIPS technique showing a narrow size distribution. Reprinted from Polymer, 37(25). J. Kiefer, J.G. Hilborn and J.L. Hedrick, Chemically induced phase separation a new technique for the synthesis of macroporous epoxy networks p 5719, Copyright (1996), with permission from Elsevier Science... 

Figure 10.1 Scanning electron micrographs (SEM) of starches separated from different sources (a) rice, (b) wheat, (c) potato, (d) maize (bar= 10 mm) (source Singh et al., 2003).

FIGURE 18.3 Scanning electron micrographs of epidermal membrane treated with dry-etch and wet-etch silicon microneedles. The epidermal membrane, consisting of stratum corneum and viable epidermis, was obtained by heat separation of full-thickness human breast skin. The tissue was immersed in distilled water preheated to 60°C for 60 s and the upper layers carefully peeled off from the dermal layer using tweezers. Epidermal membranes were treated with microneedles for 30 s at an approximate pressure of 2 kg/cm2. (a) Dry-etch microneedle-treated epidermal membrane. Bar = 200 pm (b) wet-etch microneedle-treated epidermal membrane. Bar = 500 pm. 

Figure 2.29 Scanning electron micrographs at approximately the same magnification of four microporous membranes having approximately the same particle retention, (a) Nuclepore (polycarbonate) nucleation track membrane (b) Celgard (polyethylene) expanded film membrane (c) Millipore cellulose acetate/cellulose nitrate phase separation membrane made by water vapor imbibition (Courtesy of Millipore Corporation, Billerica, MA) (d) anisotropic polysulfone membrane made by the Loeb-Sourirajan phase separation process...

N-isopropylacrylamide 1 is added to the polymerization mixture to increase hydro-phobicity of the monolith required for the separations in reversed phase mode. Vinylsulfonic acid 12 provides the chargeable functionalities that afford electroosmo-tic flow. Since the gelation occurs rapidly already at the room temperature, the filling of the channel must proceed immediately after the complete polymerization mixture is prepared. The methacryloyl moieties attached to the wall copolymerize with the monomers in the liquid mixture. Therefore, the continuous bed fills the channel volume completely and does not shrink even after all solvents are removed. Fig. 6.8 also shows scanning electron micrograph of the dry monolithic structure that exhibits features typical of macroporous polymers [34],... 

V in steps of 0.4 V. The channel length is 150 nm. The inset shows a scanning electron micrograph of the separation between the source and drain electrodes on the stamp. 

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