Sample roughness

H and B J Berne 1999. Multicanonical Jump Walking A Method for Efficiently Sampling Rough Energy Landscapes. Journal of Chemical Physics 110 10299-10306. 

Sample roughness also can produce problems in the interpretation of RBS spectra that are similar to problems encountered by sputtering techniques like AES,... 

Because of sample roughness and all other changeable settings, intensity ratios such as IA //g are employed, so that fractional monolayer coverage [Pg.177]

We also fit a Gaussian surface to the spots. The average spot width, expressed as the standard deviation of the Gaussian, was 1.6 transfers in the CSE dimension and 0.19s in the MECC dimension. Each peak migrating from the sieving capillary was sampled roughly three times as it was transferred to the second-dimension capillary. 

Stolovitzky, G. Berne, B.J., Catalytic tempering A method for sampling rough energy landscapes by Monte Carlo, Proc. Natl Acad. Set USA 2000, 97,11164—11169... 

Figure 3.14 Simulation of the effect of two types of sample roughness on the overlayer-to-substrate XPS intensity ratio (from Gunter et al. [34]).

Here is a sample rough outline using chronology as its organizing principle. 

Xu, H., Berne, B.J. Multicanonical jump walking a method for efficiently sampling rough energy landscapes. J. Chem. Phys. 1999, 110, 10299-306. 

The formal potential is determined from the mean of the anodic and cathodic peak potential of the CV in Fig. 51.3. The titanium nitride samples are very smooth. Atomic force microscopy yielded a value of the roughness mean square of 0.516 nm on an area of 5 x 5 pm2. This means that the sample roughness is negligible against the radius of the UME and the working distance in the SECM experiment and the approximation of the sample surface as a simple plane is valid. 

Since Coulomb forces decay much more slowly than van der Waals forces, an EFM experiment can be performed even without any feedback, if the sample roughness is low compared to the tip-sample distance. Terris et al. used this technique for the first time to investigate a contact electrification of a metal-insulator system [355-357]. Later, further improved experiments on contact electrification with single charge sensitivity were performed by... 

However, since AFM measures topographic and other information using a sharp tip with typical dimensions of several micrometers, opening angles of <20° to >35°, and radius of curvature of 5—50 nm (or larger), sample roughness is a crucial issue. This is also true because of the limited z-travel of most common piezo transducers, which limits the difference between the highest and lowest point on the scanned... 

A solid surface, even when apparently smooth, may have impurities and defects that vary from place to place on the surface and from sample to sample. Roughness reduces 0 when the value on a smooth surface is <90° and increases it when the value there is <90°. 

After crushing a sample roughly, all crushed particles are passed through a nonmetallic sieve with an opening of 2 mm. The passed sample is mixed sufficiently. 

Samples 3 and 4 (5 x lO and 1 x 10 ions/cm ) shows much improved performance over the unimplanted Si02. Of the two, sample 3 has the higher critical load (Lc 57.2 mN) for fracture failure. It is clear that ion-implantation does not affect the sample roughness until an ion dose of 1 x 10 ions/cm is reached. It is possible therefore that the slight decrease in critical load on sample 4 compared to sample 3 is due to the adverse influence of increasing roughness on the resistance to nanoscratch-ing wear. 

One can determine the sensitivity factor of a given spectrometer by running oneself adequate standards. It should be kept in mind that ratios of intensities may be influenced by sample roughness, as pointed out above. More crucial, they may also be influenced by the presence of adsorbed contaminants. 

Dithionite-citrate and HCl extractions of the W1 sample dissolved 70.4 mg Fe g" of sample, probably present as goethite and hematite. Assuming a composition of Fc203, this corresponds to 100.7 mg of Fe203 g of sample. Submicron sized Fe oxide particulates typically have surface areas from 20 to 50 m g a 50 m g-i value is equivalent to a crystalline Fe oxide surface area of 5.04 m g within the W1 soil sample, roughly 20% of the total surface area of the sample. The predicted U(VI) adsorption on the crystalline Fe oxide component of the schist material using this surface area is shown in Fig. 4, with the assumption that the U(VI) binding constants and the site densities are the same as observed for ferrihydrite (Table 4-4). As was found for ferrihydrite (Fig. 4-3), the calculated U(VI) adsorption is less than that observed experimentally for the W1 sample, but the prediction is much improved. 

A specific characteristic of soft stylus probes is operation at an almost constant probe-substrate distance, as the flexible probe can accommodate to the topography of the substrate. Moreover, if the probe is sufficiently flexible, it is not damaged by the sample roughness, and if the probe is softer... 

Method for Efficiently Sampling Rough Energy Landscapes. 

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