Scan Rate
Scan Rate - Related Videos
14:10
Video-rate Scanning Confocal Microscopy and Microendoscopy
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Cited by 14 •
2011
The complete construction of a custom, real-time confocal scanning imaging system is described. This system, which can be readily used for video-rate microscopy and microendoscopy, allows for an array of imaging geometries and applications not accessible using standard commercial confocal systems, at a fraction of the cost.
02:28
Leaky Scanning
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2020
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
02:53
Reaction Rate
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2020
The rate of reaction is the change in the amount of a reactant or product per unit time. Reaction rates are therefore determined by measuring the time dependence of some property that can be related to reactant or product amounts. Rates of reactions that consume or produce gaseous substances, for example, are conveniently determined by measuring changes in volume or pressure. The mathematical representation of the change in the concentration of reactants and products, over time, is the rate...
11:41
Scanning Electron Microscopy (SEM)
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2023
Source: Laboratory of Dr. Andrew J. Steckl — University of Cincinnati A scanning electron microscope, or SEM, is a powerful microscope that uses electrons to form an image. It allows for imaging of conductive samples at magnifications that cannot be achieved using traditional microscopes. Modern light microscopes can achieve a magnification of ~1,000X, while typical SEM can reach magnifications of more than 30,000X. Because the SEM doesn’t use light to create images, the resulting pictures it...
12:03
Differential Scanning Calorimetry
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2023
Source: Danielle N. Beatty and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Differential scanning calorimetry (DSC) is an important measurement to characterize thermal properties of materials. DSC is used primarily to calculate the amount of heat stored in a material as it heats up (heat capacity) as well as the heat absorbed or released during chemical reactions or phase changes. However, measurement of this heat can also lead to...
FAQs
Changing the scan rate alters how long the electrode reaction has to respond during a potential sweep and how the diffusion layer develops. For a diffusion-controlled process, peak current commonly follows the square root of scan rate, so a series of measurements can test whether diffusion is governing the observed electrochemical response.
Comparing voltammograms collected at different scan rates helps reveal whether electron transfer can keep pace with the imposed potential change. This comparison is useful for distinguishing reversible from irreversible reactions and for separating effects associated with electron-transfer kinetics from those associated with mass transport. The result is a more informative interpretation than a single scan.
Scan-rate dependence can also expose adsorption effects that may be obscured in one measurement. When responses across rates do not follow the behavior expected for diffusion control, the deviation provides evidence that material accumulated at or interacted strongly with the electrode surface. This distinction matters when interpreting redox-active compounds or evaluating whether measured current represents transport through solution alone.
Run the same electrochemical measurement at several scan rates while keeping the chemical system and measurement setup comparable, then record how current and potential features change. Comparing these responses allows investigators to examine diffusion behavior, electron-transfer kinetics, and possible adsorption effects. The resulting trend can support estimates of diffusion and kinetic parameters.
Interpret the scan-rate series together with the current response and the changing diffusion layer, rather than treating scan rate as an isolated instrument setting. Faster sweeps change the extent to which mass transport and electron-transfer kinetics influence the measurement. This context helps identify the process controlling the response and prevents overattributing a current change to a single mechanism.
Varying scan rate is useful when characterizing charge-storage materials, catalysts, and redox-active compounds. The resulting comparisons can indicate whether observed behavior is linked mainly to diffusion, electron-transfer kinetics, or adsorption, while also providing access to diffusion and kinetic parameters. In this way, scan-rate studies connect electrochemical signals with material performance and reaction behavior.