Wavelength Specificity
Wavelength Specificity - Related Videos
02:32
The de Broglie Wavelength
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2020
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
01:33
Synergistic Photobiomodulation with a Dual-Wavelength Laser in an In Vitro Disease Model
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2025
Divide the transwell system into five groups that undergo various treatments.The first group serves as the control and consists of a co-culture of neuroblastoma and microglia cells.In the second group, treat the co-culturer with fibrillar β-amyloid (fAβ) alone. fAβ induces damage in neuroblastoma cells.In the third group, treat neuroblastoma cells with an 808-nanometer laser, then co-culture them with untreated microglia.The laser reduces oxidative stress, improving neuronal survival.In the...
08:41
Single Wavelength Shadow Imaging of Caenorhabditis elegans Locomotion Including Force Estimates
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Cited by 2 •
2014
The technique presented here measures the path of freely swimming microscopic species using single wavelength exposure. C. elegans are used to demonstrate shadow imaging as an inexpensive alternative to costly microscopes. This technique can be adapted to accommodate various orientations, environments and species to measure direction, speed, acceleration and forces.
07:44
Synthesis of Wavelength-shifting DNA Hybridization Probes by Using Photostable Cyanine Dyes
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Cited by 5 •
2016
Photostable cyanine dyes are attached to oligonucleotides to monitor hybridization by energy transfer.
01:16
Specific Heat
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2019
The specific heat capacity of a substance refers to the energy required to increase the temperature of one gram of that substance by one degree Celcius. Specific heat capacity is often represented in calories (cal), grams (g), and degrees Celsius (oC), but can also be expressed in joules (J), kilograms (kg), and Kelvin (K), among other units. For example, increasing the temperature of one gram of water by 1°C requires one calorie of heat energy and can be written as 1 cal/g-°C, or 4186 J/kg/K.
FAQs
Their electrons, chemical bonds, and molecular motions can occupy only specific quantized energy levels. Radiation is absorbed or emitted when its energy matches the difference between two of those levels, producing characteristic wavelengths. Because these energy differences vary among substances, the resulting spectral pattern can help distinguish one chemical compound from another.
UV-visible measurements relate primarily to electronic transitions, whereas infrared measurements provide information from molecular bond vibrations. Fluorescence measurements examine radiation emitted after a substance absorbs energy. These techniques therefore emphasize different features of a sample, allowing chemists to select the spectral region most relevant to the chemical property or compound under investigation.
The radiation source and detector must be suited to the wavelengths associated with the transition being examined. Selecting an appropriate region increases the chance of observing the compound’s characteristic response rather than an unrelated signal. This matching supports both identification, based on spectral features, and measurement, based on the detected response at selected wavelengths.
A chemist selects a spectroscopy approach and its relevant wavelength range, exposes the sample to radiation, and records the absorbed or emitted signal. The measured spectral features can then be compared among substances for qualitative identification. Signal measurements also support quantitative analysis when the goal is to determine a compound’s concentration.
The locations of characteristic wavelengths provide qualitative information because they reflect particular energy transitions associated with a substance. The strength of the measured absorption or emission supplies quantitative information, such as concentration, when interpreted through an appropriate measurement procedure. Using both features allows one experiment to support identification and property measurement.
During a chemical reaction, changes in wavelength-dependent absorption or emission can indicate that the substances present are changing. Chemists can use these measurements to follow reaction progress rather than relying only on visual observations. The same principle extends to environmental testing, analytical chemistry, and materials research, where identifying or measuring chemical components is important.