Series scan

Scanning electron microscopy (SEM) images were taken with an AMRAY, 1800 series scanning electron microscope having a resolution of 0.2 pm. All objects in this work, except the silicon wafer microreactor, were first sputtered with a nickel layer a few nanometers thick in order to obtain an SEM image. 

Methods of Characterization The polymers were characterized by four-probe electrical conductivity measurements between room temperature and liquid nitrogen, electron spin resonance (Varlan E-line series), scanning electron microscopy (Hitachi 520), cyclic voltammetry (Princeton Applied Research Instruments), and uv-vlsl-ble spectroscopy (Perkin Elmer 330). 

Figure Bl.19.7. A series of time-lapse STM topographic images at room temperature showing a 40 mn x 40 mn area of Au(l 11). The time per frame is 8 mm, and each took about 5 min to scan. The steps shown are one atomic unit in height. The second frame shows craters left after tip-sample contact, which are two and three atoms deep. During a 2 h period the small craters have filled completely with diflhismg atoms, while the large craters continue to fill. (Taken from [29], figure 1.)...

Gewirth A A and Siegentlialer H (eds) 1995 Nano. icale Probes of the SoUd/Liquid Interface (NATO ASI Series 288) (London Kluwer) A survey of applications of scanning probes to electrochemical problems. 

In a process similar to that described in the previous item, the stored data can be used to identify not just a series of compounds but specific ones. For example, any compound containing a chlorine atom is obvious from its mass spectrum, since natural chlorine occurs as two isotopes, Cl and Cl, in a ratio of. 3 1. Thus its mass spectrum will have two molecular ions separated by two mass units (35 -i- 2 = 37) in an abundance ratio of 3 1. It becomes a trivial exercise for the computer to print out only those scans in which two ions are found separated by two mass units in the abundance ratio of 3 1 (Figure 36.10). This selection of only certain ion masses is called selected ion recording (SIR) or, sometimes, selected ion monitoring (SIM, an unfortunate... 

C. J. Chen, Introduction to Scanning TunnelingMicroscopy, Oxford Series in Optical and Imaging Sciences, Vol. 4, Oxford University Press, New York, 1993. 

R. Wiesendanger and H. J. Guntherodt, Scanning TunnelingMicroscopy III Theory of STM and Eelated S canning Probe Methods, Springer Series in Suface... 

Fig. 2. A series of progressively closer (scanning electron microscope) SEM photographs of the same membrane cross section, clearly showing skin and...

In EDXS the so-called spectrum-image method [4.122] can also be employed. A series of spectra is taken from a scanned rectangular field resulting in a data cube with its upper plane as the scanned x-y area and the third axis as the X-ray spectrum. Comprehensive information about the chemical composition and element distribution is extractable from this data set by subsequent processing. 

Electronic techniques can generate a larger number of pulses in a specified time and are therefore more accurate than mechanical devices. At the receiving end, the pulses are used to determine the state of a series of bi-stable networks. These are scanned and reset sequentially and the total number of pulses recorded. 

Replication avoids the problem of sample deterioration in the instrument, but it is destructive in that reaction of the material cannot be continued after the replica has been prepared. Transitory features cannot be detected unless a series of preparations are examined corresponding to increasing progress of the reaction considered. The textures of replicas have been shown [220] to be in satisfactory agreement with those of the original surface as viewed in the scanning electron microscope. The uses and interpretations of observations made through sample replication procedures are illustrated in the studies of decomposition of metal carboxyl-ates by Brown and co-workers [97,221—223]. 

In order to get a quantitative idea of the magnitude of the effects of these temperature variations on molecular structure and morphology an experimental study was undertaken. Two types of polymerizations were conducted. One type was isothermal polymerization at fixed reaction time at a series of temperatures. The other type was a nonisothermal polymerization in the geometry of a RIM mold. Intrinsic viscosities, size exclusion chromotograms (gpc) and differential scanning calorimetry traces (dsc) were obtained for the various isothermal products and from spatially different sections of the nonisothermal products. Complete experimental details are given below. 

---