Related Experiment Video
Updated: Feb 16, 2026
11:44
Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators
Published on: August 15, 2014
10.8K
A resistive Q-switch for low-field NMR systems
J Z Zhen1, K T O'Neill1, E O Fridjonsson1
1School of Mechanical and Chemical Engineering, University of Western Australia, Crawley, WA 6009, Australia.
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|December 27, 2017
Summary
A new NMR Q-switch reduces radiofrequency probe ring-down time in low-field NMR systems. This enables faster signal acquisition, improving measurements for applications like iron oxide particle suspensions and NMR flow meters.
Area of Science:
- Nuclear Magnetic Resonance Spectroscopy
- Applied Physics
Background:
- Low-field Nuclear Magnetic Resonance (NMR) systems often suffer from long radiofrequency (RF) probe ring-down times.
- This extended ring-down causes significant signal acquisition delays, limiting measurement speed and efficiency.
Purpose of the Study:
- To design and construct a novel NMR Q-switch for low-field NMR apparatus.
- To reduce the RF probe ring-down time and signal acquisition delay.
- To demonstrate the benefits of earlier signal acquisition in practical NMR applications.
Main Methods:
- A simple resistive damping design was implemented for the NMR Q-switch.
- The Q-switch was integrated into an Earth's magnetic field NMR system.
- The system's performance was evaluated using an aqueous suspension of iron oxide particles and an NMR flow meter.
Main Results:
- The designed NMR Q-switch effectively reduced the RF probe ring-down time.
- Signal acquisition delay was decreased from 25 ms to 9 ms.
- The improved acquisition speed demonstrated advantages in analyzing iron oxide particle suspensions and in NMR flowmetry.
Conclusions:
- The developed NMR Q-switch is a simple yet effective solution for low-field NMR.
- Faster signal acquisition significantly enhances the utility of low-field NMR systems.
- This technology shows promise for various applications requiring rapid NMR measurements.
Related Concept Videos
01:22Switching of BJT
897
Switching behavior in Bipolar Junction Transistors (BJTs) is a fundamental aspect utilized in various electronic circuits, particularly for digital logic applications like switches and amplifiers. In a typical switching circuit, a BJT alternates between cut-off and saturation modes, corresponding to the "off" and "on" states, respectively, thus behaving like an ideal switch.
Cut-off Mode ("Off" State): In this state, both the emitter-base and collector-base junctions are...
Cut-off Mode ("Off" State): In this state, both the emitter-base and collector-base junctions are...
897
01:04¹³C NMR: ¹H–¹³C Decoupling
1.9K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
1.9K
01:22Resistivity
4.6K
When a voltage is applied to a conductor, an electrical field is generated, and charges in the conductor feel the force due to the electrical field. The current density that results depends on the electrical field and the properties of the material. In some materials, including metals at a given temperature, the current density is approximately proportional to the electrical field. In these cases, the current density can be modeled as:
4.6K
01:19Resistance
6.1K
When a current moves through any conductor, the conductor causes some level of difficulty for the current to flow. The measure of that difficulty is known as the resistance of the material and is represented by R. Every material has its own resistance. In the case of conductors, heat is emitted whenever a current passes through them. Resistance depends on the resistivity of the material. Resistivity is a characteristic of the material used to fabricate electrical components, whereas the...
6.1K
01:15¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
1.7K
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
1.7K
01:18Second Order systems II
414
In an underdamped second-order system, where the damping ratio ζ is between 0 and 1, a unit-step input results in a transfer function that, when transformed using the inverse Laplace method, reveals the output response. The output exhibits a damped sinusoidal oscillation, and the difference between the input and output is termed the error signal. This error signal also demonstrates damped oscillatory behavior. Eventually, as the system reaches a steady state, the error diminishes to zero.
414