Oriented steps

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. 

Gomez R, Climent V, Feliu JM, Weaver MJ. 2000. Dependence of the potential of zero charge of stepped platinum (111) electrodes on the oriented step-edge density Electrochemical implications and comparison with work function behavior. J Phys Chem B 104 597-605. 

Finally, the minimally required number of molecular orientations (steps in cos0 and in < >) is determined experimentally by inspection of trial simulations as illustrated in Figure 6.5 on the now familiar high-spin heme spectrum too few orientations cause so-called mosaic artifacts, which must be eliminated by increasing the step numbers. In this particular example of the high-spin heme from Figure 6.2, the gx and -values are relatively close, and 25 steps in (p suffice, but gz is well separated and the number of steps in cos0 must be increased beyond 1000 to fully eliminate mosaic artifacts. 

The interpretation of voltammetry curve for the Pt(100) surface poses some problems, e.g. the origin of the peak at E=—0.15 V (Fig. 1). Markovifi et al. (12) ascribed this peak to hydrogen adsorption on particular surface imperfections, the (111)-oriented step sites. The height of this peak varies from one set of data to another, indicating a lack of control of the surface structure. Further support of this view will be shown below with the data for stepped surfaces. 

On the basis of the models in Fig. 3 and comparison with the peak for the [lio] zone, the reaction in the potential range -0.25 < E < -0.15 V could be ascribed to the hydrogen adsorption on the (111)-oriented step sites. 

Both the data on hydrogen adsorption and formic acid oxidation show pronounced structural sensitivity, thus confirming a paramount role of surface structure in electrocatalytic reactions. It can be concluded that each crystallographic orientation represents a distinct electrochemical (chemical) entity. The investigation of stepped surfaces seems to be necessary to reach an understanding of these systems on a molecular level. Hydrogen adsorption shows dependences on the terrace orientation, step orientation, and step density. All the... 

As has been mentioned, the synthesis of an organic compound always implies a sequence -either linear or convergent- of oriented steps that go from some starting materials to the target. Each one of these steps involves joining some structural units or synthons, and the following aspects must be taken into account ... 

The results here suggest that amorphous polymers are more readily orientable than semicrystalline polymers. The difficulty in orientability of semi-crystalline resins can be attributed to the fact that crystallinity is fully developed in the films prior to the orientation step.. In commercial practice, therefore, these polymers are rapidly quenched to permit orientation while still in the amorphous state. 

Orientation step Wc had good reason to celebrate last night, but even a homecoming victory is no excuse to litter. With a little effort we can preserve the beauty of our campus and our nation. Let s look at how we can begin here at Indiana University. During the next few minutes we ll focus on the extent and effects of littering on our campus and then identify what we can do about the problem. 

Recent work involved stepped Pt surfaces with controlled adsorption of Bi on step edges [73]. For the stepped singlecrystal surfaces Pt(554), Pt(332), and Pt(221), with nine-, five-, and three-atom wide terraces, respectively, the enhancement factor for HCOOH oxidation increases as the terrace width decreases. Bi appears to block adsorption of poison on reactive (110) oriented step sites and decreases the reaction ensemble size, which increases the rate on narrow (111) terraces. 

A typical tensilized process consists of the casting step, the MD-orientation step, the TD-orientation step, and another MD-orientation or tensilizing step. This second MD orientation may be performed in-line as an additional step on the... 

This machine direction stretching process is also used as the first orientation step in sequential biaxial film manufacture. 

If LSCEs are prepared using one of the methods described in Sect. 4.1, a monodomain may be obtained with respect to the main director but not necessarily for the whole phase structure. In the case of Sc elastomers an orientation of the director by mechanical stretching or by external fields yields a polydomain with respect to the layer normal. The additional orientation steps that are necessary for a full orientation of this phase are outlined in Sect. 4.2.2. 

---