Radial and axial betatron oscillation amplitude spectra in the Dubna synchrocyclotron

1969 ◽  
Vol 72 (3) ◽  
pp. 285-290
Author(s):  
V.I. Danilov ◽  
I.B. Enchevich ◽  
E.A. Polferov ◽  
E.I. Rozanov ◽  
A.N. Safonov
2019 ◽  
Author(s):  
On Kim ◽  
Jihoon Choi ◽  
Selcuk Haciomeroglu ◽  
Seungpyo Chang ◽  
Soohyung Lee ◽  
...  

2020 ◽  
Vol 14 (3) ◽  
pp. 7235-7243
Author(s):  
N.M. Ali ◽  
F. Dzaharudin ◽  
E.A. Alias

Microbubbles have the potential to be used for diagnostic imaging and therapeutic delivery. However, the transition from microbubbles currently being used as ultrasound contrast agents to achieve its’ potentials in the biomedical field requires more in depth understanding. Of particular importance is the influence of microbubble encapsulation of a microbubble near a vessel wall on the dynamical behaviour as it stabilizes the bubble. However, many bubble studies do not consider shell encapsulation in their studies. In this work, the dynamics of an encapsulated microbubble near a boundary was studied by numerically solving the governing equations for microbubble oscillation. In order to elucidate the effects of a boundary to the non-linear microbubble oscillation the separation distances between microbubble will be varied along with the acoustic driving. The complex nonlinear vibration response was studied in terms of bifurcation diagrams and the maximum radial expansion. It was found that the increase in distance between the boundary and the encapsulated bubble will increase the oscillation amplitude. When the value of pressure amplitude increased the single bubble is more likely to exhibit the chaotic behaviour and maximum radius also increase as the inter wall-bubble distance is gradually increased. While, with higher driving frequency the maximum radial expansion decreases and suppress the chaotic behaviour.


2019 ◽  
Author(s):  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anatoliy Kuznetsov ◽  
Qi Zhang ◽  
Phillip Christopher ◽  
...  

Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites, but dramatically greater rate acceleration on that same active site is achieved when the surface intermediates oscillate in binding energy. The applied oscillation amplitude and frequency can accelerate reactions orders of magnitude above the catalytic rates of static systems, provided the active site dynamics are tuned to the natural frequencies of the surface chemistry. In this work, differences in the characteristics of parallel reactions are exploited via selective application of active site dynamics (0 < ΔU < 1.0 eV amplitude, 10<sup>-6</sup> < f < 10<sup>4</sup> Hz frequency) to control the extent of competing reactions occurring on the shared catalytic surface. Simulation of multiple parallel reaction systems with broad range of variation in chemical parameters revealed that parallel chemistries are highly tunable in selectivity between either pure product, even when specific products are not selectively produced under static conditions. Two mechanisms leading to dynamic selectivity control were identified: (i) surface thermodynamic control of one product species under strong binding conditions, or (ii) catalytic resonance of the kinetics of one reaction over the other. These dynamic parallel pathway control strategies applied to a host of chemical conditions indicate significant potential for improving the catalytic performance of many important industrial chemical reactions beyond their existing static performance.


2021 ◽  
Vol 127 (2) ◽  
Author(s):  
Leonardo Kopprio ◽  
Christophe Longeaud ◽  
Federico Ventosinos ◽  
Javier Schmidt

Author(s):  
Shirui Feng ◽  
Xi Wu ◽  
Zhenquan Wang ◽  
Tao Niu ◽  
Qiong Chen

AbstractWith the continuous expansion of power systems and the application of power electronic equipment, forced oscillation has become one of the key problems in terms of system safety and stability. In this paper, an interline power flow controller (IPFC) is used as a power suppression carrier and its mechanism is analyzed using the linearized state-space method to improve the system damping ratio. It is shown that although the IPFC can suppress forced oscillation with well-designed parameters, its capability of improving the system damping ratio is limited. Thus, combined with the repetitive control method, an additional repetitive controller (ARC) is proposed to further dampen the forced power oscillation. The ARC control scheme is characterized by outstanding tracking performance to a system steady reference value, and the main IPFC controller with the ARC can provide higher damping, and further reduce the amplitude of oscillations to zero compared with a supplementary damping controller (SDC). Simulation results show that the IPFC with an ARC can not only greatly reduce the oscillation amplitude, but also actively output the compensation power according to the reference value of the ARC tracking system.


Nanophotonics ◽  
2020 ◽  
Vol 9 (13) ◽  
pp. 4117-4126 ◽  
Author(s):  
Igor Gershenzon ◽  
Geva Arwas ◽  
Sagie Gadasi ◽  
Chene Tradonsky ◽  
Asher Friesem ◽  
...  

AbstractRecently, there has been growing interest in the utilization of physical systems as heuristic optimizers for classical spin Hamiltonians. A prominent approach employs gain-dissipative optical oscillator networks for this purpose. Unfortunately, these systems inherently suffer from an inexact mapping between the oscillator network loss rate and the spin Hamiltonian due to additional degrees of freedom present in the system such as oscillation amplitude. In this work, we theoretically analyze and experimentally demonstrate a scheme for the alleviation of this difficulty. The scheme involves control over the laser oscillator amplitude through modification of individual laser oscillator loss. We demonstrate this approach in a laser network classical XY model simulator based on a digital degenerate cavity laser. We prove that for each XY model energy minimum there corresponds a unique set of laser loss values that leads to a network state with identical oscillation amplitudes and to phase values that coincide with the XY model minimum. We experimentally demonstrate an eight fold improvement in the deviation from the minimal XY energy by employing our proposed solution scheme.


1981 ◽  
Vol 8 (8) ◽  
pp. 931-934 ◽  
Author(s):  
C. D. Weidman ◽  
E. P. Krider ◽  
M. A. Uman
Keyword(s):  

Author(s):  
Akin Tatoglu ◽  
Claudio Campana

Unmanned Aerial Vehicles (UAV) are commonly used for robotics research and industrial purposes. Most of the autonomous applications use visual sensors and inertial measurement units for localization. Design constraints of such systems are defined considering smooth operation requirements such as indoor environments without external forces where input tracking signal is constant during an operation. In this research paper, we simultaneously investigate and compare stability, power consumption and landmark tracking quality of a visual sensor mounted gimbal specifically for rapid UAV motion requirements where input signal continuously varies such as at obstacle rich environments. We not only attempt to find efficient control parameters but also compare these settings with power consumption and landmark tracking quality metric which are vital for mobile robots and localization algorithms. Efficiency of the system response is analyzed with rise and settling time as well as oscillation amplitude and frequencies. These parameters are tested and benchmarked with various voltage and current limitations. In addition to that, different response behaviors were investigated considering landmark tracking quality metrics including feature detection and image blur. We have shown that gimbal stabilization controller under continuously varying input signal requires less responsive behavior to keep landmark tracking accuracy stable. Initial simulation results, system development and experimental setup procedure are explained and behavior plots for each topic are listed and analyzed.


Sign in / Sign up

Export Citation Format

Share Document