Effect of resonant charge exchange on heat conduction in plasmas.
Cross section estimates for symmetric resonant charge exchange between ions differing by one electronic charge, noting effect on heat conduction in plasmas
IONIZATION CROSS SECTION↗
SEARCH · Search NASA
Results for “RESONANCE EFFECT”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Polaritonic Bright and Dark States Collectively Affect the Reactivity of a Hydrolysis Reaction
Vibrational strong coupling (VSC) has emerged as a means for modifying chemical reactivity. Despite the intriguing discoveries and progresses in the field, the precise mechanisms that govern polaritonic chemistry still deserve further interrogation. Herein, we use the hydrolysis of ammonia borane in D 2 O as an exemplary reaction and systematically investigate the influence of VSC on its reactivity. Experimental evidence of the coexistence of a resonant effect and reaction acceleration is observed in this system. In particular, we find that when the O-D stretching mode of D 2 O is strongly coupled to a cavity mode, reaction acceleration is observed. The reaction rate acceleration factor, mu, is consistently observed to be dependent on the coupling conditions between the vibrational and cavity modes, and reaches a minimum at zero mode detuning, suggesting that a resonant effect is likely in play. In addition, we find that mu decreases with an increasing Rabi splitting. Based on these experimental findings, we propose that the overall influence of VSC on this reaction is likely determined collectively by the polaritonic bright and dark states. In conclusion, these findings could help shed new light on the intricate effects of VSC on ground-state reaction landscapes.
Rabi splitting↗
The effect of three-dimensional, non-linear resonances on the motion of a particle near the Earth-Moon equilateral libration points
Three dimensional, nonlinear resonance effects on motion of particles near earth-moon equilateral libration points
Schechter, H. B.↗
Far-infrared self-broadening in methylcyanide - Absorber-perturber resonance
Using tunable far-infrared spectrometers with high-frequency stability and accuracy, the self-pressure broadening and shift of CH3CN are measured. Evidence of absorber-perturber resonance effects on the collisional line shape are obtained. This tests the theoretical model and its possible improvements and also allows predictions of broadening and shift for a large class of molecules. Moreover, the resonance effect produces a theoretical temperature dependence of self-broadening that is different from what is commonly assumed.
Buffa, G.↗
Effects of Resonance in Quasi-Periodic Oscillators of Neutron Star Binaries
Using a large quantity of Rossi X-Ray Timing Explorer data presented in the literature, I offer a detailed investigation into the accuracy of the quasi-periodic oscillation (QPO) frequency determination. The QPO phenomenon seen in X-ray binaries is possibly a result of the resonance of the intrinsic (eigen) oscillations and harmonic driving forces of the system. I show that the resonances, in the presence of the damping of oscillations, occur at frequencies that are systematically and randomly shifted with respect to the eigenfrequencies of the system. The shift value strongly depends on the damping rate that is measured by the half-width of the QPO feature. Taking into account this effect, I analyze the QPO data for four Z sources, Scorpius X-I, GX 340+0, GX 5-1, and GX 17+2, and two atoll sources, 4U 1728-34 and 4U 0614+09. The transition-layer model (TLM) predicts the existence of the invariant quantity delta, an inclination angle of the magnetospheric axis with respect to the normal to the disk. I calculate delta and the error bars of delta using the resonance shift, and I find that the inferred delta-values are consistent with constants for these four Z sources, in which horizontal-branch oscillation and kilohertz frequencies have been detected and correctly identified. It is shown that the inferred delta are in the range between 5.5 deg and 6.5 deg. I conclude that the TLM seems to be compatible with the data.
Titarchuk, Lev↗
Damper reduces effects of resonance on force transducer
Viscous-film damper eliminates response lag of resonance generated noise when inserted into the thrust measuring system. This technique can be applied to automated devices when pulsed force or low order impact is involved, and where signal noise is produced by stopping or reversal of mechanical travel or by water hammer.
Postma, R. W.↗
Aerosol-induced laser breakdown thresholds - Effect of resonant particles
Laser intensity thresholds for the onset of stimulated Raman scattering and the breakdown in resonant micron-sized droplets are reduced to below those for nonresonant droplets by a factor of about 3. This reduction is most likely caused by the enhancement of electromagnetic energy (photon) densities within the droplets over and above that in nonresonant droplets. The magnitude of the threshold reduction for breakdown is consistent with the assertion that: (1) input (pump) wavelength resonances that initiate plasma have cavity Qs of about 10 exp 4; and (2) finite regions of high-electromagnetic-energy density within the droplet, with dimensions of the order of the Debye length, are required to initiate plasma.
Pinnick, R. G.↗
Radiation Effects on Resonant Tunneling Diodes: Preliminary Results
We have observed enhanced bistability (hysteresis) in the current-voltage characteristics of gamma irradiated resonant tunneling diodes. This bistability occurs in the negative differential conductance region for voltages larger than 1.1 V. We discuss possible mechanisms for the observed phenomena and also discuss the measurements sensitivity to the external circuit.
Wilkins, R.↗
Tungsten resonance integrals and Doppler coefficients Final report
Doppler coefficients and effective resonance integrals of natural and enriched tungsten samples at high temperatures
DOPPLER EFFECT↗
Saturation effects in cyclotron resonance oscillators
Large signal saturation effects in cyclotron resonance oscillators, using helical electron beam-cavity interaction model
Rowe, J. F., Jr.↗
The movement of small particulate matter in the early solar system and the formation of satellites
The motions of the abundant small particulate matter in the early solar system are discussed. The effects of gas drag and resonance effects of perturbing forces could have led to accretion and differentiation of the matter. The composition of the moon and the existence of the rings of Saturn can be explained on the basis of the assembly of small particulate matter in satellite orbits around the planets.
Gold, T.↗
Nonlinear Resonant Oscillations of Gas in Optimized Acoustical Resonators and the Effect of Central Blockage
Optimizing resonator shapes for maximizing the ratio of maximum to minimum gas pressure at an end of the resonator is investigated numerically. It is well known that the resonant frequencies and the nonlinear standing waveform in an acoustical resonator strongly depend on the resonator geometry. A quasi-Newton type scheme was used to find optimized axisymmetric resonator shapes achieving the maximum pressure compression ratio with an acceleration of constant amplitude. The acoustical field was solved using a one-dimensional model, and the resonance frequency shift and hysteresis effects were obtained through an automation scheme based on continuation method. Results are presented for optimizing three types of geometry: a cone, a horn-cone and a half cosine-shape. For each type, different optimized shapes were found when starting with different initial guesses. Further, the one-dimensional model was modified to study the effect of an axisymmetric central blockage on the nonlinear standing wave.
Li, Xiaofan↗
Nonlinear Resonant Oscillations of Gas in Optimized Acoustical Resonators and the Effect of Central Blockage
Optimizing resonator shapes for maximizing the ratio of maximum to minimum gas pressure at an end of the resonator is investigated numerically. It is well known that the resonant frequencies and the nonlinear standing waveform in an acoustical resonator strongly depend on the resonator geometry. A quasi-Newton type scheme was used to find optimized axisymmetric resonator shapes achieving the maximum pressure compression ratio with an acceleration of constant amplitude. The acoustical field was solved using a one-dimensional model, and the resonance frequency shift and hysteresis effects were obtained through an automation scheme based on continuation method. Results are presented for optimizing three types of geometry: a cone, a horn-cone and a half cosine- shape. For each type, different optimized shapes were found when starting with different initial guesses. Further, the one-dimensional model was modified to study the effect of an axisymmetric central blockage on the nonlinear standing wave.
Li, Xiao-Fan↗
A vibration study of the C. S. I. R. O. 210-ft radio telescope.
Vibration analysis of CSIRO 210-ft radio telescope, discussing natural frequencies, structure resonance effects, error detection, etc
VIBRATION EFFECT↗
Effect of Parasitic Dielectric Resonators on CPW/Aperture-Coupled Dielectric Resonator Antennas
The effects of parasitic dielectric resonators on the HE (sub 11 sigma) and HE (High Efficiency) (sub 13 sigma) modes of a cylindrical dielectric resonator antenna (DRA) have been studied. The DRA was excited electromagnetically with a grounded coplanar waveguide through an aperture in the common ground plane. Strong couplings were observed for the HE (sub 11 sigma) mode with the parasitic element superimposed on the driven DRA, and for the HE (sub 13 sigma) mode with parasitic elements placed on both sides of the driven DRA. Results indicate significant enhancement in bandwidth for both modes, and good radiation patterns for the HE (sub 11 sigma) mode.
Simons, R. N.↗
Ion effects on ionospheric electron resonance phenomena
Ion effects are often observed on topside-sounder-stimulated electron plasma wave phenomena and the present study is concerned with the spur effect relative to electron plasma resonance. A spur appears after a time delay corresponding to the proton gyroperiod and is observed mainly on the resonances at the electron plasma frequency and the harmonics of the electron cyclotron frequency. Proton spurs occur at the harmonic resonances only, when the electron plasma waves associated with these resonances are susceptible to the Harris instability and when the electromagnetic wave can be initiated by the sounder pulse. This instability results from a sounder-stimulated anisotropic electron velocity distribution. The observations suggest that energy is fed into the harmonics of the longitudinal plasma wave from the electromagnetic wave through wave-mode coupling. The observations were made during eight passes of the Alouette-2 satellite.
Benson, R. F.↗
Effects of specimen resonances on acoustic-ultrasonic testing
The effects of specimen resonances on acoustic ultrasonic (AU) nondestructive testing were investigated. Selected resonant frequencies and the corresponding normal mode nodal patterns of the aluminum block are measured up to 75.64 kHz. Prominent peaks in the pencil lead fracture and sphere impact spectra from the two transducer locations corresponded exactly to resonant frequencies of the block. It is established that the resonant frequencies of the block dominated the spectral content of the output signal. The spectral content of the output signals is further influenced by the transducer location relative to the resonant frequency nodal lines. Implications of the results are discussed in relation to AU parameters and measurements.
Williams, J. H., Jr.↗
Ion effects on ionospheric electron resonance phenomena
Ion effects are often observed on topside-sounder stimulated electron plasma wave phenomena. A commonly observed effect is a spur, appearing after a time delay corresponding to the proton gyro period, attached to the low frequency side of an electron plasma resonance. The spurs are often observed on the resonances at the electron plasma frequency f sub N, the harmonics nf sub H of the electron cyclotron frequency f sub H (n = 2, 3, 4, ...), and occasionally on the upper hybrid frequency. The spurs on the f sub N resonance are usually quite small unless the f sub N resonance overlaps with an nf sub H resonance; very large spurs are observed during such overlap conditions. Proton spurs are only observed on the nf sub H resonances when the electron plasma waves associated with these resonances are susceptible to the Harris instability and when the electromagnetic z wave can be initiated by the sounderpulse. This instability is the result of a sounder stimulated anisotropic electron velocity distribution. The observations suggest that energy is fed into the nf sub H longitudinal plasma wave from the z wave via wave-mode coupling. The magnitude of the nf sub H spurs for large n is much greater than for small n.
Benson, R. F.↗