Molecular Diameter
Molecular Diameter - Related Videos
11:37
Propeller Characterization: Variations in Pitch, Diameter, and Blade Number on Performance
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2023
Source: Shreyas Narsipur, Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC A propeller is a twisted airfoil, where the angle of the chord changes with respect to the location, along the radial station, as shown in Figure 1. Propellers are widely used in aircraft and watercraft propulsion systems thereby necessitating detailed characterizations of propellers to design high performance vehicles. Figure 1. Chord, thickness, and pitch at a radial station. One of...
06:54
MR Molecular Imaging of Prostate Cancer with a Small Molecular CLT1 Peptide Targeted Contrast Agent
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Cited by 3 •
2013
To demonstrate MR cancer molecular imaging with a small peptide targeted MRI contrast agent specific to clotted plasma proteins in tumor stroma in a mouse prostate cancer model.
09:55
Molecular Cloning
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2023
Molecular cloning is a set of methods, which are used to insert recombinant DNA into a vector - a carrier of DNA molecules that will replicate recombinant DNA fragments in host organisms. The DNA fragment, which may be a gene, can be isolated from a prokaryotic or eukaryotic specimen. Following isolation of the fragment of interest, or insert, both the vector and insert must be cut with restriction enzymes and purified. The purified pieces are joined together though a technique called...
12:02
Molecular Evolution of the Tre Recombinase
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Cited by 4 •
2008
Here we report the generation of Tre recombinase through directed, molecular evolution. Tre recombinase recognizes a pre-defined target sequence within the LTR sequences of the HIV-1 provirus, resulting in the excision and eradication of the provirus from infected human cells. While still in its infancy, directed molecular evolution will allow the creation of custom enzymes that will serve as tools of molecular surgery and molecular medicine.
02:00
Molecular Models
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2020
Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models makes it easier to visualize the structures and shapes of atoms and molecules. Skeletal Model Simpler two-dimensional representations of chemical compounds are accomplished using skeletal models. The illustration shows only the molecular framework or bonds without explicitly showing the atoms. In this representation, many of the carbon atoms...
FAQs
An effective collision diameter sets the center-to-center separation at which two molecules are treated as interacting. In a finite-sphere model, this distance determines the spatial range available for encounters, so changing the diameter changes predicted collision frequency. The parameter therefore links an idealized molecular interaction rule to measurable behavior in gases and other particle systems.
A molecule’s geometric extent need not match its effective collision diameter. Geometry describes the structure itself, whereas scattering and transport measurements reflect how the molecule behaves during interactions or motion. Consequently, the reported size depends on the physical question and measurement approach, rather than representing one universal distance applicable to every molecular-scale phenomenon.
In kinetic theory, molecular diameter helps account for the fact that gas particles occupy finite effective sizes and interact during close approaches. Those assumptions influence how particle motion is connected to pressure. Using an appropriate diameter allows a model to relate microscopic encounter behavior to macroscopic gas properties without treating molecules as dimensionless points.
Diffusion and viscosity describe transport, or the movement and flow of matter. Molecular diameter enters their interpretation because it characterizes the scale of particle interactions and motion. A diameter inferred from transport behavior can therefore help connect microscopic molecular properties with macroscopic transport measurements, especially when modeling gases or fluids.
To estimate molecular diameter experimentally, researchers can begin with molecular geometry, analyze scattering behavior, or examine transport behavior. Each route provides a size relevant to a different physical description. The resulting value is then used as an effective parameter in a model, allowing observed molecular-scale behavior to be compared with predictions for collisions or fluid transport.
Molecular diameter is especially useful when a calculation must bridge individual particles and bulk behavior. In physics, it appears in kinetic theory and statistical mechanics, supports fluid modeling, and helps interpret molecular-scale experiments. These applications use the parameter to translate assumptions about molecular size and encounters into predictions or explanations for pressure, diffusion, viscosity, and collision frequency.