Double Focusing
Double Focusing - Related Videos
08:58
Double Emulsion Generation Using a Polydimethylsiloxane (PDMS) Co-axial Flow Focus Device
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Cited by 8 •
2015
Microfluidic double emulsions generation typically involves devices with patterned wettability or custom-fabricated glass components. Here we describe the fabrication and testing of an all polydimethylsiloxane (PDMS) double emulsion generator that does not require surface treatment or complicated fabrication processes, and is capable of producing double emulsions down to 14 µm.
09:30
Focused Ion Beams
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2023
Source: Sina Shahbazmohamadi and Peiman Shahbeigi-Roodposhti-Roodposhti, School of Engineering, University of Connecticut, Storrs, CT As electron microscopes become more complex and widely used in research labs, it becomes more of a necessity to introduce their capabilities. Focused ion beam (FIB) is an instrument that can be employed in order to fabricate, trim, analyze and characterize materials on mico- and nano-scales in a wide variety of fields from nano-electronics to medicine. FIB...
02:04
Fixing Double-strand Breaks
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The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
01:16
Focusing of Light in the Eye
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2024
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
01:27
Coping Strategies: Problem Focused
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2025
Coping strategies are methods people use to manage, tolerate, or reduce the effects of stressors. These strategies involve both behavioral and psychological actions to handle stressful situations. One common approach is problem-focused coping, which aims to change or eliminate the source of stress rather than merely addressing its consequences. This method involves taking direct action to resolve the issue causing stress. For example, consider a student who struggles to understand their...
FAQs
The electrostatic sector compensates for energy-related dispersion by focusing ions according to kinetic energy. Ions entering with different energies would otherwise follow different trajectories, reducing the sharpness of the measured signal. By correcting this energy dependence within the combined focusing process, the analyzer helps ions sharing a mass-to-charge ratio converge more effectively, supporting higher mass resolution.
The magnetic sector contributes a different selection principle: it separates ions according to momentum rather than kinetic energy alone. This distinction matters because ions with the same mass-to-charge ratio can arrive with trajectory or energy differences. When magnetic separation is paired with electrostatic focusing, momentum-dependent separation complements energy correction, allowing the instrument to discriminate ions that would otherwise overlap.
Double focusing improves resolution because it addresses two independent sources of ion dispersion: differences in direction and differences in energy. Correcting only one source would leave the other broadening the measured ion feature. The combined arrangement therefore produces a more defined focus for a given mass-to-charge ratio, which is especially valuable when neighboring ions have very similar values.
During analysis, the ion beam encounters the electrostatic and magnetic sectors, whose complementary fields focus and separate ions using kinetic energy and momentum. Ions with the same mass-to-charge ratio are brought toward a common focus, where their signals can be compared. This workflow connects controlled ion motion with measurements of masses, isotope abundances, and elemental composition.
For isotope abundance measurements, the improved separation helps distinguish signals associated with different isotopes when their mass-to-charge ratios are close. The instrument’s ability to bring ions of a given mass-to-charge ratio into a common focus supports more precise comparison of their measured abundances. This capability helps prevent closely spaced isotope signals from being treated as one unresolved feature.
Accurate atomic and molecular mass measurements require effective separation of ions that may have closely spaced mass-to-charge ratios. By correcting directional and energy-related dispersion together, the analyzer produces sharper focusing and more precise ion separation. The resulting measurements can support accurate mass assignments, helping distinguish closely related atomic or molecular signals in chemical analysis.
Double Focusing is particularly valuable when a complex sample produces ions with very similar mass-to-charge ratios. Its combined correction of trajectory and energy differences improves separation among these signals, enabling high-resolution analysis rather than a single blended response. In analytical chemistry, this supports interpretation of isotope patterns, accurate masses, and elemental compositions within chemically crowded measurements.