SU-DD-A1-02: Variations of Energy Spectra and Water-To-Material Stopping-Power Ratios in Three-Dimensional Conformal and IMRT Photon Fields

2006 ◽  
Vol 33 (6Part2) ◽  
pp. 1985-1985
Author(s):  
S Jang ◽  
H Liu ◽  
J Siebers ◽  
R Mohan
Keyword(s):  
Three Dimensional ◽  
Energy Spectra ◽  
Stopping Power

Variations in energy spectra and water-to-material stopping-power ratios in three-dimensional conformal and intensity-modulated photon fields

2007 ◽  
Vol 34 (4) ◽  
pp. 1388-1397 ◽  
Author(s):  
Si Young Jang ◽  
H. Helen Liu ◽  
Radhe Mohan ◽  
Jeffrey V. Siebers
Keyword(s):  
Three Dimensional ◽  
Energy Spectra ◽  
Stopping Power ◽  
Intensity Modulated

scholarly journals On inertial-range scaling laws

1996 ◽  
Vol 306 ◽  
pp. 167-181 ◽  
Author(s):  
John C. Bowman
Keyword(s):  
Steady State ◽  
High Resolution ◽  
Scaling Laws ◽  
State Energy ◽  
Three Dimensional ◽  
Inertial Range ◽  
Energy Spectra ◽  
Two Dimensional ◽  
Unified Framework ◽  
Asymptotic Nature

Inertial-range scaling laws for two- and three-dimensional turbulence are re-examined within a unified framework. A new correction to Kolmogorov's k−5/3 scaling is derived for the energy inertial range. A related modification is found to Kraichnan's logarithmically corrected two-dimensional enstrophy-range law that removes its unexpected divergence at the injection wavenumber. The significance of these corrections is illustrated with steady-state energy spectra from recent high-resolution closure computations. Implications for conventional numerical simulations are discussed. These results underscore the asymptotic nature of inertial-range scaling laws.

Three-Dimensional Lithography for Rutile TiO2 Single Crystals using Swift Heavy Ions

2003 ◽  
Vol 797 ◽  
Author(s):  
Koichi Awazu ◽  
Makoto Fujimaki ◽  
Yoshimichi Ohki ◽  
Tetsuro Komatsubara
Keyword(s):  
Single Crystal ◽  
Hydrofluoric Acid ◽  
Ion Irradiation ◽  
Three Dimensional ◽  
Heavy Ion ◽  
High Energy ◽  
Stopping Power ◽  
A Value ◽  
Microscopy Measurement ◽  
Electronic Stopping Power

ABSTRACTWe have developed a nano-micro structure fabrication method in rutile TiO2 single crystal by use of swift heavy-ion irradiation. The area where ions heavier than Cl ion accelerated with MeV-order high energy were irradiated was well etched by hydrofluoric acid, by comparison etching was not observed in the pristine TiO2 single crystal. Noticed that the irradiated area could be etched to a depth at which the electronic stopping power of the ion decayed to a value of 6.2keV/nm. We also found that the value of the electronic stopping power was increased, eventually decreased against depth in TiO2 single crystal with, e.g. 84.5MeV Ca ion. Using such a beam, inside of TiO2 single crystal was selectively etched with 20% hydrofluoric acid, while the top surface of TiO2 single crystal subjected to irradiation was not etched. Roughness of the new surface created in the single crystal was within 7nm with the atomic forth microscopy measurement.

Simulation of Artificial Turbulence by the Vortex Method

2002 ◽  
Author(s):  
Yoshifumi Ogami ◽  
Kazuie Nishiwaki ◽  
Yoshinobu Yoshihara
Keyword(s):  
Turbulent Flows ◽  
Three Dimensional ◽  
Vortex Method ◽  
Energy Spectra ◽  
System Of Nonlinear Equations ◽  
Vortex Methods ◽  
Velocity Fluctuations ◽  
Integral Scales ◽  
Relative Errors ◽  
Les Model

First, a simple and accurate numerical method is presented to produce velocity fluctuations that are determined by the prescribed physical quantities and qualities of turbulence such as longitudinal and lateral spectra, and integral scales. The fluctuations are obtained by solving a system of nonlinear equations that are derived from the equations of energy spectra and of root mean square of the fluctuations. This method requires as many computer memories and computations as one-dimensional case even for the three dimensional calculations. It is shown that there is a strong resemblance of the simulated velocity fluctuations and experimental data. The energy spectra of these velocity fluctuations are quite accurate with less than 0.01% relative errors to the prescribed spectra. Secondly, these solutions are used to examine the capability of the vortex methods to produce turbulent flows with the prescribed parameters. It is found that although the energy spectra by the vortex method scatter to some extent, they are distributed along the prescribed spectra. It can be said that the vortex methods are able to simulate the target turbulence fairly well. Also it is found that the solutions with the LES model increase and deviate from the target spectrum at the higher frequency regions. This may suggest the nonessentiality of the LES model for the vortex method.

scholarly journals Formation of Power-law Electron Energy Spectra in Three-dimensional Low-β Magnetic Reconnection

2019 ◽  
Vol 884 (2) ◽  
pp. 118 ◽  
Author(s):  
Xiaocan Li ◽  
Fan Guo ◽  
Hui Li ◽  
Adam Stanier ◽  
Patrick Kilian
Keyword(s):  
Magnetic Reconnection ◽  
Electron Energy ◽  
Power Law ◽  
Three Dimensional ◽  
Energy Spectra

scholarly journals General principles for describing electronic and proton multiple scattering processes in solids

2021 ◽  
Vol 2144 (1) ◽  
pp. 012016
Author(s):  
V P Afanas’ev ◽  
L G Lobanova ◽  
D N Selyakov ◽  
M A Semenov-Shefov
Keyword(s):  
Experimental Data ◽  
Distribution Function ◽  
Analytical Solution ◽  
Multiple Scattering ◽  
Satisfactory Agreement ◽  
Length Distribution ◽  
Energy Spectra ◽  
Stopping Power ◽  
Reflected Light ◽  
Light Ions

Abstract Analytical solution for the reflected light ions Pass Length Distribution Function (PLDF) equation is obtained. Reflected ions energy spectra calculated on the basis of the developed method shows satisfactory agreement with experimental data. The effectiveness of the developed methodology in the procedure for verifying the stopping power value is indicated.

scholarly journals On bubble clustering and energy spectra in pseudo-turbulence

2010 ◽  
Vol 650 ◽  
pp. 287-306 ◽  
Author(s):  
JULIÁN MARTÍNEZ MERCADO ◽  
DANIEL CHEHATA GÓMEZ ◽  
DENNIS VAN GILS ◽  
CHAO SUN ◽  
DETLEF LOHSE
Keyword(s):  
Isotropic Turbulence ◽  
Liquid Velocity ◽  
Pair Correlation ◽  
Bubble Diameter ◽  
Three Dimensional ◽  
Radial Distance ◽  
Energy Spectra ◽  
Bubble Velocity ◽  
Vertical Orientation ◽  
Gaussian Form

Three-dimensional particle tracking velocimetry (PTV) and phase-sensitive constant temperature anemometry in pseudo-turbulence – i.e. flow solely driven by rising bubbles – were performed to investigate bubble clustering and to obtain the mean bubble rise velocity, distributions of bubble velocities and energy spectra at dilute gas concentrations (α ≤ 2.2 %). To characterize the clustering the pair correlation function G(r, θ) was calculated. The deformable bubbles with equivalent bubble diameter db = 4–5 mm were found to cluster within a radial distance of a few bubble radii with a preferred vertical orientation. This vertical alignment was present at both small and large scales. For small distances also some horizontal clustering was found. The large number of data points and the non-intrusiveness of PTV allowed well-converged probability density functions (PDFs) of the bubble velocity to be obtained. The PDFs had a non-Gaussian form for all velocity components and intermittency effects could be observed. The energy spectrum of the liquid velocity fluctuations decayed with a power law of −3.2, different from the ≈ −5/3 found for homogeneous isotropic turbulence, but close to the prediction −3 by Lance & Bataille (J. Fluid Mech., vol. 222, 1991, p. 95) for pseudo-turbulence.

scholarly journals Transition to turbulence in an elliptic vortex

1996 ◽  
Vol 307 ◽  
pp. 43-62 ◽  
Author(s):  
T. S. Lundgren ◽  
N. N. Mansour
Keyword(s):  
Swirling Flow ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Periodic Wave ◽  
Transition To Turbulence ◽  
Energy Spectra ◽  
Small Scale ◽  
Two Dimensional ◽  
Secondary Instabilities ◽  
Vortex Tubes

Stability and transition to turbulence are studied in a simple incompressible two-dimensional bounded swirling flow with a rectangular planform – a vortex in a box. This flow is unstable to three-dimensional disturbances. The instability takes the form of counter-rotating swirls perpendicular to the axis which bend the vortex into a periodic wave. As these swirls grow in amplitude the primary vorticity is compressed into thin vortex layers. These develop secondary instabilities which roll up into vortex tubes. In this way the flow attains a turbulent state which is populated by intense elongated vortex tubes and weaker vortex layers which spiral around them. The flow was computed at two Reynolds numbers by spectral methods with up to 2563 resolution. At the higher Reynolds number broad three-dimensional shell-averaged energy spectra are found with nearly a decade of Kolmogorov k−5/3 law and small-scale isotropy.

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