Institute of Scientific and Technical Information of China (English)
Miha Brojan; Matjaz Cebron; Franc Kosel
2012-01-01
This work studies large deflections of slender,non-prismatic cantilever beams subjected to a combined loading which consists of a non-uniformly distributed continuous load and a concentrated load at the free end of the beam.The material of the cantilever is assumed to be nonlinearly elastic.Different nonlinear relations between stress and strain in tensile and compressive domain are considered.The accuracy of numerical solutions is evaluated by comparing them with results from previous studies and with a laboratory experiment.
Calculation of Uniform of Beam Scanning
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
For the electron beam application, it is always scanned by a dipole magnet. The uniform of the scanning has great influence for some application, such as the irradiation of the thyristor. There are two methods for improving the scanning uniform:
Beam uniformity of flat top lasers
Chang, Chao; Cramer, Larry; Danielson, Don; Norby, James
2015-03-01
Many beams that output from standard commercial lasers are multi-mode, with each mode having a different shape and width. They show an overall non-homogeneous energy distribution across the spot size. There may be satellite structures, halos and other deviations from beam uniformity. However, many scientific, industrial and medical applications require flat top spatial energy distribution, high uniformity in the plateau region, and complete absence of hot spots. Reliable standard methods for the evaluation of beam quality are of great importance. Standard methods are required for correct characterization of the laser for its intended application and for tight quality control in laser manufacturing. The International Organization for Standardization (ISO) has published standard procedures and definitions for this purpose. These procedures have not been widely adopted by commercial laser manufacturers. This is due to the fact that they are unreliable because an unrepresentative single-pixel value can seriously distort the result. We hereby propose a metric of beam uniformity, a way of beam profile visualization, procedures to automatically detect hot spots and beam structures, and application examples in our high energy laser production.
Continuous Reinforced Concrete Beams
DEFF Research Database (Denmark)
Hoang, Cao Linh; Nielsen, Mogens Peter
1996-01-01
This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...... at the limit state of serviceability is in some simple cases determined by setting up the statical and the compatibility conditions.With these moment distributions, the maximum deflection and the reinforcement stresses at the span middle and at a support are calculated.The results are compared with results...
Analytical examination of a spiral beam scanning method for uniform irradiation
Energy Technology Data Exchange (ETDEWEB)
Fukuda, Mitsuhiro; Okumura, Susumu; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment
1997-03-01
A new circular beam scanning method for uniform irradiation of high-energy, intense ion beams over a large area has been developed. A sweeping speed and a trajectory density in a radial direction are kept constant to obtain uniform fluence distribution. A radial position of a beam spot on a target and an angular frequency of the circular motion are expressed by an irrational function of time. The beam is swept continuously, and a beam trajectory becomes spiral. More than 90 % uniformity of the fluence distribution can been achieved over a large area. (author)
Uniform irradiation system using beam scanning method for cyclotron
International Nuclear Information System (INIS)
JAERI AVF-cyclotron is equipped with an ion beam scanner for large area irradiation. The two-dimensional fluence distribution of ion beam obtained using cellulose triacetate film dosimeter was not uniform. This is resulted from the distortion of excitation current for electromagnet of the scanner. So, the beam scanning condition, i.e., the relation between the ion species, the beam profile and the scanning width, was extremely limited to make a good uniformity. We have developed a beam scanning simulator to get fluence distributions by calculation and then compared the simulated distributions with the measured ones. It was revealed that the both of them are in good agreement and the beam scanning condition to get good uniformity was led by using this simulator. On the basis of these results, the power supply of scanner was improved. A good uniformity of beam distribution was available. (author)
Transverse vibrations of arbitrary non-uniform beams
Institute of Scientific and Technical Information of China (English)
郭树起; 杨绍普
2014-01-01
Free and steady state forced transverse vibrations of non-uniform beams are investigated with a proposed method, leading to a series solution. The obtained series is verified to be convergent and linearly independent in a convergence test and by the non-zero value of the corresponding Wronski determinant, respectively. The obtained solution is rigorous, which can be reduced to a classical solution for uniform beams. The proposed method can deal with arbitrary non-uniform Euler-Bernoulli beams in principle, but the methods in terms of special functions or elementary functions can only work in some special cases.
Spiral wobbling beam illumination uniformity in HIF fuel target implosion
Kawata S.; Kurosaki T.; Koseki S.; Hisatomi Y.; Barada D.; Ma Y.Y.; Ogoyski A.I.
2013-01-01
A few % wobbling-beam illumination nonuniformity is realized in heavy ion inertial confinement fusion (HIF) throughout the heavy ion beam (HIB) driver pulse by a newly introduced spiraling beam axis motion in the first two rotations. The wobbling HIB illumination was proposed to realize a uniform implosion in HIF. However, the initial imprint of the wobbling HIBs was a serious problem and introduces a large unacceptable energy deposition nonuniformity. In the wobbling HIBs illumination, the i...
Ring lens for producing uniform density ion beams
International Nuclear Information System (INIS)
Frequently one needs to irradiate a circular target uniformly with a positive ion beam from an accelerator. The typical beam is peaked on the axis and has a more or less Gaussian radial distribution, so that it would be advantageous to be able to fold the tails of the Gaussian inward to give a uniform flux on the target. A lens, which is quite unconventional, was designed and built for that purpose and has operated successfully for many months on the 5 MV electrostatic accelerator at this laboratory. The general concepts and lens structure are presented here
Ring lens for focusing ion beams to uniform densities
International Nuclear Information System (INIS)
An electrostatic lens was designed and built to focus a beam of positive ions into uniform density on a target. The lens has two concentric field regions with a grid separating the inner zero field from the outer radial field. For proper operation the incident ions must emanate with axial symmetry and Gaussian or similar divergence from a small source. An appendix is included on the symmetrization of elliptical beams by a quadrupole singlet lens. (U.S.)
Continuity of non-uniform recursive subdivision surfaces
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Since Doo-Sabin and Catmull-Clark surfaces were proposed in 1978, eigenstructure, convergence and continuity analyses of stationary subdivision have been performed very well, but it has been very difficult to prove the convergence and continuity of non-uniform recursive subdivision surfaces (NURSSes, for short) of arbitrary topology. In fact, so far a problem whether or not there exists the limit surface as well as G1 continuity of a non-uniform Catmull-Clark subdivision has not been solved yet. Here the concept of equivalent knot spacing is introduced. A new technique for eigenanalysis, convergence and continuity analyses of non-uniform Catmull-Clark surfaces is proposed such that the convergence and G1 continuity of NURSSes at extraordinary points are proved. In addition, slightly improved rules for NURSSes are developed. This offers us one more alternative for modeling free-form surfaces of arbitrary topologies with geometric features such as cusps, sharp edges, creases and darts, while elsewhere maintaining the same order of continuity as B-spline surfaces.
Continuity of non-uniform recursive subdivision surfaces
Institute of Scientific and Technical Information of China (English)
秦开怀; 王华维
2000-01-01
Since Doo-Sabin and Catmull-Clark surfaces were proposed in 1978, eigenstructure, convergence and continuity analyses of stationary subdivision have been performed very well, but it has been very difficult to prove the convergence and continuity of non-uniform recursive subdivision surfaces (NURSSes, for short) of arbitrary topology. In fact, so far a problem whether or not there exists the limit surface as well as G1 continuity of a non-uniform Catmull-Clark subdivision has not been solved yet. Here the concept of equivalent knot spacing is introduced. A new technique for eigenanaly-sis, convergence and continuity analyses of non-uniform Catmull-Clark surfaces is proposed such that the convergence and G1 continuity of NURSSes at extraordinary points are proved. In addition, slightly improved rules for NURSSes are developed. This offers us one more alternative for modeling free-form surfaces of arbitrary topologies with geometric features such as cusps, sharp edges, creases and darts, while elsewhere ma
Light beams focusing in periodically non-uniform crystalline medium
Directory of Open Access Journals (Sweden)
S.N.Kurilkina
2002-03-01
Full Text Available In the present paper the peculiarities of propagation and diffraction of optical waves in the crystalline periodically non-uniform media are considered. The dependence of light beam divergence in the crystal on curvatures of wave vector surface is obtained. It is shown, that presence of the periodic non-uniformity of the crystal and natural anisotropy lead to essential deformation of wave vector surface, namely, to the appearance of local regions with negative curvature and, hence, to the effect of light focusing in corresponding directions. The application of uniform electric field may intensify the light focusing. The crystalline diffraction lenses are proposed which are controlled by electric field and variation of incident light polarization.
Spiraling Beam Illumination Uniformity on Heavy Ion Fusion Target
Kurosaki, T; Noguchi, K; Koseki, S; Barada, D; Ma, Y Y; Ogoyski, A I; Barnard, J J; Logan, B G
2012-01-01
A few percent wobbling-beam illumination nonuniformity is realized in heavy ion inertial confinement fusion (HIF) by a spiraling beam axis motion in the paper. So far the wobbling heavy ion beam (HIB) illumination was proposed to realize a uniform implosion in HIF. However, the initial imprint of the wobbling HIBs was a serious problem and introduces a large unacceptable energy deposition nonuniformity. In the wobbling HIBs illumination, the illumination nonuniformity oscillates in time and space. The oscillating-HIB energy deposition may contribute to the reduction of the HIBs illumination nonuniformity. The wobbling HIBs can be generated in HIB accelerators and the oscillating frequency may be several 100MHz-1GHz. Three-dimensional HIBs illumination computations presented here show that the few percent wobbling HIBs illumination nonuniformity oscillates successfully with the same wobbling HIBs frequency.
Spiral wobbling beam illumination uniformity in HIF fuel target implosion
Directory of Open Access Journals (Sweden)
Kawata S.
2013-11-01
Full Text Available A few % wobbling-beam illumination nonuniformity is realized in heavy ion inertial confinement fusion (HIF throughout the heavy ion beam (HIB driver pulse by a newly introduced spiraling beam axis motion in the first two rotations. The wobbling HIB illumination was proposed to realize a uniform implosion in HIF. However, the initial imprint of the wobbling HIBs was a serious problem and introduces a large unacceptable energy deposition nonuniformity. In the wobbling HIBs illumination, the illumination nonuniformity oscillates in time and space. The oscillating-HIB energy deposition may produce a time-dependent implosion acceleration, which reduces the Rayleigh-Taylor (R-T growth [Laser Part. Beams 11, 757 (1993, Nuclear Inst. Methods in Phys. Res. A 606, 152 (2009, Phys. Plasmas 19, 024503 (2012] and the implosion nonuniformity. The wobbling HIBs can be generated in HIB accelerators and the oscillating frequency may be several 100 MHz ∼ 1 GHz [Phys. Rev. Lett. 104, 254801 (2010]. Three-dimensional HIBs illumination computations present that the few % wobbling HIBs illumination nonuniformity oscillates with the same wobbling HIBs frequency.
Spiral wobbling beam illumination uniformity in HIF fuel target implosion
Kawata, S.; Kurosaki, T.; Koseki, S.; Hisatomi, Y.; Barada, D.; Ma, Y. Y.; Ogoyski, A. I.
2013-11-01
A few % wobbling-beam illumination nonuniformity is realized in heavy ion inertial confinement fusion (HIF) throughout the heavy ion beam (HIB) driver pulse by a newly introduced spiraling beam axis motion in the first two rotations. The wobbling HIB illumination was proposed to realize a uniform implosion in HIF. However, the initial imprint of the wobbling HIBs was a serious problem and introduces a large unacceptable energy deposition nonuniformity. In the wobbling HIBs illumination, the illumination nonuniformity oscillates in time and space. The oscillating-HIB energy deposition may produce a time-dependent implosion acceleration, which reduces the Rayleigh-Taylor (R-T) growth [Laser Part. Beams 11, 757 (1993), Nuclear Inst. Methods in Phys. Res. A 606, 152 (2009), Phys. Plasmas 19, 024503 (2012)] and the implosion nonuniformity. The wobbling HIBs can be generated in HIB accelerators and the oscillating frequency may be several 100 MHz ˜ 1 GHz [Phys. Rev. Lett. 104, 254801 (2010)]. Three-dimensional HIBs illumination computations present that the few % wobbling HIBs illumination nonuniformity oscillates with the same wobbling HIBs frequency.
The Continuous Electron Beam Accelerator Facility
International Nuclear Information System (INIS)
On February 13, 1987, construction started on the Continuous Electron Beam Accelerator Facility - a 4-GeV, 200-μA, continuous beam, electron accelerator facility designed for nuclear physics research. The machine has a racetrack configuration with two antiparallel, 500-MeV, superconducting linac segments connected by beam lines to allow four passes of recirculation. The accelerating structure consists of 1500-MHz, five-cell niobium cavities developed at Cornell University. A liquid helium cryogenic system cools the cavities to an operating temperature of 2 K. Beam extraction after any three of the four passes allows simultaneous delivery of up to three beams of independently variable currents and different, but correlated, energies to the three experimental areas. Beam breakup thresholds exceed the design current by nearly two orders of magnitude. Project completion and the start of physics operations are scheduled for 1993. The total estimated cost is $255 million
Helicon waves in uniform plasmas. IV. Bessel beams, Gendrin beams, and helicons
Urrutia, J. M.; Stenzel, R. L.
2016-05-01
Electromagnetic waves in the low frequency whistler mode regime are investigated experimentally and by digital data superposition. The radiation from a novel circular antenna array is shown to produce highly collimated helicon beams in a uniform unbounded plasma. The differences to Bessel beams in free space are remarked upon. Low divergence beams arise from the parallel group velocity of whistlers with phase velocity either along the guide field or at the Gendrin angle. Waves with angular momentum are produced by phasing the array in the circular direction. The differences in the field topologies for positive and negative modes numbers are shown. It is also shown that in uniform plasmas, the radial amplitude profile of the waves depends on the antenna field topology. Thus, there are no helicon "eigenmodes" with radial Bessel function profiles in uniform plasmas. It is pointed out that phase measurements in helicon devices indicate radial wave propagation which is inconsistent with helicon eigenmode theory based on paraxial wave propagation. Trivelpiece-Gould modes also exist in uniform unbounded plasmas.
Characterization of uniform scanning proton beams with analytical models
Demez, Nebi
Tissue equivalent phantoms have an important place in radiation therapy planning and delivery. They have been manufactured for use in conventional radiotherapy. Their tissue equivalency for proton beams is currently in active investigation. The Bragg-Kleeman rule was used to calculate water equivalent thickness (WET) for available tissue equivalent phantoms from CIRS (Norfolk, VA, USA). WET's of those phantoms were also measured using proton beams at Hampton University Proton Therapy Institute (HUPTI). WET measurements and calculations are in good agreement within ˜1% accuracy except for high Z phantoms. Proton beams were also characterized with an analytical proton dose calculation model, Proton Loss Model (PLM) [26], to investigate protons interactions in water and those phantoms. Depth-dose and lateral dose profiles of protons in water and in those phantoms were calculated, measured, and compared. Water Equivalent Spreadness (WES) was also investigated for those phantoms using the formula for scattering power ratio. Because WES is independent of incident energy of protons, it is possible to estimate spreadness of protons in different media by just knowing WES. Measurements are usually taken for configuration of the treatment planning system (TPS). This study attempted to achieve commissioning data for uniform scanning proton planning with analytical methods, PLM, which have been verified with published measurements and Monte Carlo calculations. Depth doses and lateral profiles calculated by PLM were compared with measurements via the gamma analysis method. While gamma analysis shows that depth doses are in >90% agreement with measured depth doses, the agreement falls to PLM data were imported into the TPS (PLM-TPS). PLM-TPS was tested with different patient cases. The PLM-TPS treatment plans for 5 prostate cases show acceptable agreement. The Planning Treatment Volume (PTV) coverage was 100 % with PLM-TPS except for one case in which the coverage is 99%. The
Nonlinear free vibrations of centrifugally stiffened uniform beams at high angular velocity
Bekhoucha, F.; Rechak, S.; Duigou, L.; Cadou, J. M.
2016-09-01
In this paper, we study the bending nonlinear free vibrations of a centrifugally stiffened beam with uniform cross-section and constant angular velocity. The nonlinear intrinsic equations of motion used here are geometrically exact and specific to beams exhibiting large amplitude displacements and rotations associated with small strains. Based on the Timoshenko beam model, these equations are derived from Hamilton's principle, in which the warping is considered. All coupling terms are considered including Coriolis terms. The studied beams are isotropic with clamped-free boundary conditions. By combining the Galerkin method with the harmonic balance method, the equations of motion are converted into a quadratic function treated with a continuation method: the Asymptotic Numerical Method, where the generalized displacement vector is presented as a series expansion. While analysing the effect of the angular velocity, we determine the amplitude versus frequency variations which are plotted as backbone curves. Considering the first lagging and flapping modes, the changes in beam behaviour from hardening to softening are investigated and identified as a function of the angular velocity and the effect of shear. Particular attention is paid to high angular velocities for both Euler-Bernoulli and Timoshenko beams and the natural frequencies so obtained are compared with the results available in the literature.
On natural frequencies of non-uniform beams modulated by finite periodic cells
Xu, Yanlong; Zhou, Xiaoling; Wang, Wei; Wang, Longqi; Peng, Fujun; Li, Bin
2016-09-01
It is well known that an infinite periodic beam can support flexural wave band gaps. However, in real applications, the number of the periodic cells is always limited. If a uniform beam is replaced by a non-uniform beam with finite periodicity, the vibration changes are vital by mysterious. This paper employs the transfer matrix method (TMM) to study the natural frequencies of the non-uniform beams with modulation by finite periodic cells. The effects of the amounts, cross section ratios, and arrangement forms of the periodic cells on the natural frequencies are explored. The relationship between the natural frequencies of the non-uniform beams with finite periodicity and the band gap boundaries of the corresponding infinite periodic beam is also investigated. Numerical results and conclusions obtained here are favorable for designing beams with good vibration control ability.
International Nuclear Information System (INIS)
Avoiding undesirable thermal stress or damage of a target vessel is an essential subject in high-intensity beam irradiation for accelerator-driven neutron production. A promising method to tailor the transverse beam intensity distribution for uniform beam irradiation on the target is the use of multipole magnets. We, therefore, study the transformation and uniformization of the transverse intensity distribution by means of nonlinear focusing induced from multipole magnets. It is theoretically described how the intensity distribution is transformed and made uniform by the nonlinear focusing force. Large-area uniform proton and heavy-ion beams are experimentally formed using octupole magnets at the azimuthally-varying-field cyclotron in Japan Atomic Energy Agency. (author)
Nonlinear Stability of Intense Mismatched Beams in a Uniform Focusing Field
Pakter, Renato; Simeoni, Wilson
2005-01-01
We investigate the nonlinear coupling between axisymmetric and elliptic oscillations in the dynamics of intense beams propagating in a uniform magnetic focusing field. It is shown that finite amplitude mismatched oscillations of an initially round beam may destabilize elliptic oscillations, heavily affecting stability and the shape of the beam. This is a potential mechanics for beam particle loss in such systems. Self consistent simulations are performed to verify the findings.
Institute of Scientific and Technical Information of China (English)
LU Shan-shan; ZHENG Wen-zhong
2010-01-01
To study the plastic properties of reactive powder concrete continuous beams reinforced with GFRP bars,the calculation programs for moment redistribution coefficients are prepared by using nonlinear analysis methods such as moment-curvature,conjugate beam method and so on.By comparing the test results of existed FRP bars reinforced concrete continuous beams with simulation results,the accuracy of the calculation program is verified.Then 18 simulated GFRP bars reinforced reactive powder concrete continuous beams are selected whose change parameters are reinforcement ratio of mid-span and middle support.Through the nonlinear analysis of simulated beams,moment redistribution coefficients under mid-span concentrated loads,one-third point loads and uniformly distributed loads are obtained respectively.Thus the formula of moment redistribution coefficients is obtained by fitting moment redistribution coefficients and factors.The results show that the reactive powder concrete continuous beams reinforced with GFRP bars have good plastic properties.
On Uniform Decay of Solutions for Extensible Beam Equation with Strong Damping
Institute of Scientific and Technical Information of China (English)
FENG Bao-wei; ZHANG Ming; LIANG Tie-wang; LI Hai-yan
2014-01-01
This paper investigates the existence and uniform decay of global solutions to the initial and boundary value problem with clamped boundary conditions for a nonlinear beam equation with a strong damping.
Institute of Scientific and Technical Information of China (English)
Guangyan JIA; Na ZHANG
2013-01-01
In this paper, we prove that a kind of second order stochastic differential op-erator can be represented by the limit of solutions of BSDEs with uniformly continuous coeﬃcients. This result is a generalization of the representation for the uniformly continu-ous generator. With the help of this representation, we obtain the corresponding converse comparison theorem for the BSDEs with uniformly continuous coeﬃcients, and get some equivalent relationships between the properties of the generator g and the associated so-lutions of BSDEs. Moreover, we give a new proof about g-convexity.
An approximate solution for the free vibrations of rotating uniform cantilever beams
Peters, D. A.
1973-01-01
Approximate solutions are obtained for the uncoupled frequencies and modes of rotating uniform cantilever beams. The frequency approximations for flab bending, lead-lag bending, and torsion are simple expressions having errors of less than a few percent over the entire frequency range. These expressions provide a simple way of determining the relations between mass and stiffness parameters and the resultant frequencies and mode shapes of rotating uniform beams.
Yang, Yin-Kuang; Wu, Yu-Xiang; Lin, Te-Hsun; Yu, Chun-Wen; Fu, Chien-Chung
2016-03-01
Laser interference lithography (LIL) is a maskless lithography technique with many advantages such as simple optical design, inexpensive, infinite depth of focus, and large area patterning with single exposure. However, the intensity of normal laser beam is Gaussian distribution. In order to obtain large area uniform structure, we have to expand the laser beam much bigger than the wafer and use only the center part of the beam. Resulting in wasting lots of energy and the production capacity decrease. In this study, we designed a beam shaping device which consists of two parallel fused silicon optical window with different coating on both side. Two optical window form an air thin film. When the expanded laser beam pass through the device, the beam will experience many refraction and reflection between two optical window and interference with each other. The transmittance of laser beam will depend on the incident angle. The output intensity distribution will change from Gaussian distribution to a flat top distribution. In our experiment, we combined the beam shaping device with a Lloyd's mirror LIL system. Experiment results indicated that the LIL system with beam shaping device can obtain large area uniform pattern. And compare with the traditional Lloyd's mirror LIL system, the exposure time is shorten up to 4.5 times. In conclusion, this study design a beam flattening device for LIL system. The flat top beam can improve the large area uniformity and the production capacity of LIL. Making LIL more suitable for industry application.
Free Vibration Analysis for Cracked FGM Beams by Means of a Continuous Beam Model
E Chuan Yang; Xiang Zhao; Ying Hui Li
2015-01-01
Based on Euler-Bernoulli beam theory and a continuous stiffness beam model, the free vibration of rectangular-section beams made of functionally graded materials (FGMs) containing open edge cracks is studied. Assuming the material gradients follow exponential distribution along beam thickness direction, the conversion relation between the vibration governing equations of a FGM beam and that of an isotropic homogenous beam is deduced. A continuous function is used to characterize the bending s...
Bending and rotational behaviour of semi-continuous composite beams
Institute of Scientific and Technical Information of China (English)
2008-01-01
Stresses and deflections were measured in various semi-continuous composite beams.The bending and rotational capacities of the composite connections were measured in terms of beam curvatures and deflections by using two full-scale semi-rigid composite frames with monotonic loadings.The effect of semi-rigid connections on the performance of composite beams with various loadings was compared with predictions and codes.The tests show that the semi-continuous composite beams are more economic and effective than the simple or continuous composite beams.The semi-rigid connections affect the bending capacities and beam deflections,so the connection behavior should be considered in the design of composite beams.Yielding analysis of the steel beam bottom flange has some influence on the deflection calculation of composite beams.
Linear elastic analysis of thin laminated beams with uniform and symmetric cross-section
Directory of Open Access Journals (Sweden)
Zajíček M.
2008-12-01
Full Text Available This paper deals with analyses of linear elastic thin beams which are consisted of the homogeneous orthotropic layers. The cross-sections of these beams are assumed uniform and symmetric. Governing equations of one-dimensional model are derived on the base of the Timoshenko's beam theory. An evaluation of shear correction factor consists in conservation of the shear strain energy. This factor is calculated in this paper but only in the cases of the static problem. The general static solution for the flexural and axial displacement and for the slope of the cross-section is found. Further, the possibility of calculation of the free vibrations of beams are also presented. The obtained results for the static solution are compared with the results of numerical solution based on the finite element method. The numerical model is prepared in software package MARC. As a tested example is used the uniformly loaded simply supported beam with various cross-sections.
Li, Li; Gu, Chun; Xu, Lixin; Zhou, Shenlei
2016-04-01
The self-adapting algorithms are improved to optimize a beam configuration in the direct drive laser fusion system with the solid state lasers. A configuration of 32 laser beams is proposed for achieving a high uniformity illumination, with a root-mean-square deviation at 10-4 level. In our optimization, the parameters such as beam number, beam arrangement, and beam intensity profile are taken into account. The illumination uniformity robustness versus the parameters such as intensity profile deviations, power imbalance, intensity profile noise, the pointing error, and the target position error is also discussed. In this study, the model is assumed a solid-sphere illumination, and refraction effects of incident light on the corona are not considered. Our results may have a potential application in the design of the direct-drive laser fusion of the Shen Guang-II Upgrading facility (SG-II-U, China).
Uniformity of reshaped beam by diffractive optical elements with light-emitted diode illumination
Chen, Mengzhu; Gu, Huarong; Wang, Qixia; Tan, Qiaofeng
2015-10-01
Due to its low energy consumption, high efficiency and fast switching speed, light-emitted diode (LED) has been used as a new light source in optical wireless communication. To ensure uniform lighting and signal-to-noise ratio (SNR) during the data transmission, diffractive optical elements (DOEs) can be employed as optical antennas. Different from laser, LED has a low temporal and spatial coherence. And its impacts upon the far-field diffraction patterns of DOEs remain unclear. Thus the mathematical models of far-field diffraction intensity for LED with a spectral bandwidth and source size are first derived in this paper. Then the relation between source size and uniformity of top-hat beam profile for LEDs either considering the spectral bandwidth or not are simulated. The results indicate that when the size of LED is much smaller than that of reshaped beam, the uniformity of reshaped beam obtained by light source with a spectral bandwidth is significantly better than that by a monochromatic light. However, once the size is larger than a certain threshold value, the uniformity of reshaped beam of two LED models are almost the same, and the influence introduced by spectral bandwidth can be ignored. Finally the reshaped beam profiles are measured by CCD camera when the areas of LED are 0.5×0.5mm2 and 1×1mm2. And the experimental results agree with the simulations.
Extension of the non-uniform warping theory to an orthotropic composite beam
Ghazouani, Nejib; El Fatmi, Rached
2010-12-01
This Note proposes an extension to composite section of the non-uniform (out-of-plane) warping beam theory recently established for homogeneous and isotropic beam by R. El Fatmi (C. R. Mecanique 335 (2007) 467-474). For the present work, which constitutes a first step of this extension, the cross-section is assumed to be symmetric and made by orthotropic materials; however, Poisson's effects (called here in-plane warping) are also taken into account. Closed form results are given for the structural behavior of the composite beam and for the expressions of the 3D stresses; these ones, easy to compare with 3D Saint Venant stresses, make clear the additional contribution of the new internal forces induced by the non-uniformity of the (in and out) warpings. As first numerical applications, results on torsion and shear-bending of a cantilever sandwich beam are presented.
Laser-cooled continuous ion beams
Energy Technology Data Exchange (ETDEWEB)
Schiffer, J.P.; Hangst, J.S.; Nielsen, J.S. [and others
1995-08-01
A collaboration with a group in Arhus, Denmark, using their storage ring ASTRID, brought about better understanding of ion beams cooled to very low temperatures. The longitudinal Schottky fluctuation noise signals from a cooled beam were studied. The fluctuation signals are distorted by the effects of space charge as was observed in earlier measurements at other facilities. However, the signal also exhibits previously unobserved coherent components. The ions` velocity distribution, measured by a laser fluorescence technique suggests that the coherence is due to suppression of Landau damping. The observed behavior has important implications for the eventual attainment of a crystalline ion beam in a storage ring. A significant issue is the transverse temperature of the beam -- where no direct diagnostics are available and where molecular dynamics simulations raise interesting questions about equilibrium.
Stability of Thin-Walled Beams with Lateral Continuous Restraint
Directory of Open Access Journals (Sweden)
Balázs Ivan
2015-06-01
Full Text Available Metal beams of thin-walled cross-sections have been widely used in building industry as members of load-bearing structures. Their resistance is usually limited by lateral torsional buckling. It can be increased in case a beam is laterally supported by members of cladding or ceiling construction. The paper deals with possibilities of determination of critical load of thin-walled beams with lateral continuous restraint which is crucial for beam buckling resistance assessment
Van Blarigan, Louis; Moehlis, Jeff; McMeeking, Robert
2015-06-01
A model is developed for a non-uniform piezoelectric beam suitable for analyzing energy harvesting behavior. System dynamics are projected onto a numerically developed basis to produce energy functions which are used to derive equations of motion for the system. The resulting model reproduces the experimentally observed transition to chaos while providing a conservative estimate of power output and bandwidth.
Coral, W.; Rossi, C.; Curet, O. M.
2015-12-01
This paper presents a Differential Quadrature Element Method for free transverse vibration of a robotic fish based on a continuous and non-uniform flexible backbone with distributed masses (fish ribs). The proposed method is based on the theory of a Timoshenko cantilever beam. The effects of the masses (number, magnitude and position) on the value of natural frequencies are investigated. Governing equations, compatibility and boundary conditions are formulated according to the Differential Quadrature rules. The convergence, efficiency and accuracy are compared to other analytical solution proposed in the literature. Moreover, the proposed method has been validate against the physical prototype of a flexible fish backbone. The main advantages of this method, compared to the exact solutions available in the literature are twofold: first, smaller computational cost and second, it allows analysing the free vibration in beams whose section is an arbitrary function, which is normally difficult or even impossible with other analytical methods.
Topological features of vector vortex beams perturbed with uniformly polarized light
D'Errico, Alessio; Piccirillo, Bruno; de Lisio, Corrado; Cardano, Filippo; Marrucci, Lorenzo
2016-01-01
Optical singularities manifesting at the center of vector vortex beams are unstable, since their topological charge is higher than the lowest value permitted by Maxwell's equations. Inspired by conceptually similar phenomena occurring in the polarization pattern characterizing the skylight, we show how perturbations that break the symmetry of radially symmetric vector beams lead to the formation of a pair of fundamental and stable singularities, i.e. points of circular polarization. We prepare a superposition of a radial (or azimuthal) vector beam and a uniformly linearly polarized Gaussian beam; by varying the amplitudes of the two fields, we control the formation of pairs of these singular points and their spatial separation. We complete this study by applying the same analysis to vector vortex beams with higher topological charges, and by investigating the features that arise when increasing the intensity of the Gaussian term. Our results can find application in the context of singularimetry, where weak fi...
Stability and halo formation of a breathing axisymmetric uniform-density beam
Gluckstern, Robert L.; Cheng, Wen-Hao; Kurennoy, Sergey S.; Ye, Huanchan
1996-12-01
An analysis of the stability and halo formation is presented for a breathing axisymmetric beam of uniform density [Kapchinsky-Vladimirsky (KV) beam] in a uniform focusing channel. Theoretical results are obtained for the form of modes involving nonuniform charge density. In particular, the mismatch-tune depression space is explored, both analytically and by numerical particle-in-cell simulations, to determine the stability limits and growth rates of the most unstable modes. The implications for halo formation are then explored. Halo parameters obtained by simulations are compared with predictions of an analytical model for halo formation from the breathing KV beam developed earlier. The practical applications of the results for high-current linear accelerators are discussed.
Stability and halo formation of a breathing axisymmetric uniform-density beam
Energy Technology Data Exchange (ETDEWEB)
Gluckstern, R.L.; Cheng, W.; Kurennoy, S.S.; Ye, H. [Physics Department, University of Maryland, College Park, Maryland 20742 (United States)
1996-12-01
An analysis of the stability and halo formation is presented for a breathing axisymmetric beam of uniform density [Kapchinsky-Vladimirsky (KV) beam] in a uniform focusing channel. Theoretical results are obtained for the form of modes involving nonuniform charge density. In particular, the mismatch-tune depression space is explored, both analytically and by numerical particle-in-cell simulations, to determine the stability limits and growth rates of the most unstable modes. The implications for halo formation are then explored. Halo parameters obtained by simulations are compared with predictions of an analytical model for halo formation from the breathing KV beam developed earlier. The practical applications of the results for high-current linear accelerators are discussed. {copyright} {ital 1996 The American Physical Society.}
Numerical analysis of reinforced concrete continuous deep beams
Asin, M.; Walraven, J.
1995-01-01
The structural behaviour of deep beams is still not completely understood, since, for example, plane sections do not remain plane and no uniform shear flow can develop because of the small ratio between depth and shear span. If in addition, the supporting system is also statically indeterminate, the
Devianto, Dodi
2016-02-01
It is constructed convolution of generated random variable from independent and identically exponential distribution with stabilizer constant. The characteristic function of this distribution is obtained by using Laplace-Stieltjes transform. The uniform continuity property of characteristic function from this convolution is obtained by using analytical methods as basic properties.
Computer simulations for intense continuous beam transport in electrostatic lens systems
Institute of Scientific and Technical Information of China (English)
ZHAO Xiao-Song; L(U) Jian-Qin
2008-01-01
A code LEADS based on the Lie algebraic analysis for the continuous beam dynamics with space charge effect in beam transport has been developed.The program is used for the simulations of axial-symmetric and unsymmetricalintense continuous beam in the channels including drift spaces.electrostatic lenses and DC electrostatic accelerating tubes.In order to get the accuracy required,all elements are divided into many small segments,and the electric field in the segments is regarded as uniform field,and the dividing points are treated as thin lenses.Iteration procedures are adopted in the program to obtain self-consistent solutions.The code can be used in the designs of low energy beam transport systems,electrostatic accelerators and ion implantation machines.
Behavior of Uniform Anisotropic Beams of Rectangular Section under Transverse Impact of a Mass
Directory of Open Access Journals (Sweden)
Lu Chun
1997-01-01
Full Text Available A numerical method is presented to investigate the dynamic response of uniform orthotropic beams subjected to an impact of a mass. Higher order shear deformation and rotary inertia are included in the analysis of the beams. The impactor and laminated composite beam are treated as a system. The nonlinear differential governing equations of motion are then derived based on the Lagrange principle and modified nonlinear contact law, and solved numerically. The solution procedure is applicable to arbitrary boundary conditions. Numerical results are compared with those available in the literature to demonstrate the validity of the method, and very good agreement is achieved. The effects of boundary conditions on the contact force, contact duration, stress distributions, and beam deflection are discussed.
Beam Focusing by a Non-Uniformly-Spaced Nanoslit Array in a Metallic Film
Institute of Scientific and Technical Information of China (English)
JIAO Xiao-Jin; WANG Pei; ZHANG Dou-Guo; LU Yong-Hua; XIE Jian-Ping; MING Hai
2006-01-01
@@ A finite difference time domain simulation has been performed to analyse the optical transmission through a non-uniformly-spaced nanoslit array in silver film. The phase change of surface plasmons propagating on the silver film is used to modulate the initial phase of the output beam. The beam deflection and focusing function are designed, and the focal depth of the focusing metallic structure are mainly considered. It is found that the focal depth can be controlled by altering the effective width of this structure, i.e. the number of slits, when the relative spacing is fixed.
Directory of Open Access Journals (Sweden)
Xin Su
2015-01-01
Full Text Available There have been many studies regarding antenna polarization; however, there have been few publications on the analysis of the channel capacity for polarized antenna systems using the beamforming technique. According to Chung et al., the channel capacity is determined by the density of scatterers and the transmission power, which is obtained based on the assumption that scatterers are uniformly distributed on a 3D spherical scattering model. However, it contradicts the practical scenario, where scatterers may not be uniformly distributed under outdoor environment, and lacks the consideration of fading channel gain. In this study, we derive the channel capacity of polarized uniform linear array (PULA systems using the beamforming technique in a practical scattering environment. The results show that, for PULA systems, the channel capacity, which is boosted by beamforming diversity, can be determined using the channel gain, beam radiation pattern, and beamforming diversity order (BDO, where the BDO is dependent on the antenna characteristics and array configurations.
Production of uniform ion beam of large area in a magnetically-insulatd diode
International Nuclear Information System (INIS)
The results of experimental investigation of a magnetically insulated diode generating a powerful ribbon ion beam with 100x10 cm cross section are presented. Modification of the known diode designs allowed to provide the constancy of the electric and magnetic field by the anode length and uniform generation of the ion beam over the larger part of its length. At the same time these measures have decreased considerably electron losses in the anode up to 1-2 A/cm2 that reduces the efficiency of anode plasma formation during the first part of a high-voltage pulse. At 500 kV anode voltage the ion current amplitude is 18 kA, the beam-out energy - 460 J, the efficiency of ion generation - 85%
Sellin, P J; Galbiati, A; Maghrabi, M; Townsend, P D
2002-01-01
The uniformity of response of CVD diamond radiation detectors produced from high quality diamond film, with crystallite dimensions of >100 mu m, has been studied using ion beam induced charge imaging. A micron-resolution scanning alpha particle beam was used to produce maps of pulse height response across the device. The detectors were fabricated with a single-sided coplanar electrode geometry to maximise their sensitivity to the surface region of the diamond film where the diamond crystallites are highly ordered. High resolution ion beam induced charge images of single crystallites were acquired that demonstrate variations in intra-crystallite charge transport and the termination of charge transport at the crystallite boundaries. Cathodoluminescence imaging of the same crystallites shows an inverse correlation between the density of radiative centres and regions of good charge transport.
Eigenfrequencies and eigenmodes of a beam with periodically continuously varying spatial properties
DEFF Research Database (Denmark)
Sorokin, Vladislav S.; Thomsen, Jon Juel
2015-01-01
A beam with periodically continuously varying spatial properties is analyzed. This structure is a generic model for various systems widely used in industry, e.g. risers, rotor blades, and similar. The aim is to reveal effects of periodic spatial modulation both on the beam eigenfrequencies...... and eigenmodes. Special attention is given to "mid-frequency" eigenmodes having period of the same order as the period of modulation, which cannot be captured by the conventional analytical methods. In particular, the paper addresses prediction of bandgaps and their influence on the distribution...... of modulation on eigenfrequencies, and that modulations of the beam mass per unit length and of the beam stiffness affect them oppositely. It is shown that eigenmodes having a period close to the period of modulation comprise a long-wave component; this illustrates the capacity of non-uniform structures...
Apparatus and methods for continuous beam fourier transform mass spectrometry
McLuckey, Scott A.; Goeringer, Douglas E.
2002-01-01
A continuous beam Fourier transform mass spectrometer in which a sample of ions to be analyzed is trapped in a trapping field, and the ions in the range of the mass-to-charge ratios to be analyzed are excited at their characteristic frequencies of motion by a continuous excitation signal. The excited ions in resonant motions generate real or image currents continuously which can be detected and processed to provide a mass spectrum.
Continuous guided beams of slow and internally cold polar molecules
Sommer, Christian; Motsch, Michael; Pohle, Sebastian; Bayerl, Josef; Pinkse, Pepijn W H; Rempe, Gerhard
2008-01-01
We describe the combination of buffer-gas cooling with electrostatic velocity filtering to produce a high-flux continuous guided beam of internally cold and slow polar molecules. In a previous paper (L.D. van Buuren et al., arXiv:0806.2523v1) we presented results on density and state purity for guided beams of ammonia and formaldehyde using an optimized set-up. Here we describe in more detail the technical aspects of the cryogenic source, its operation, and the optimization experiments that we performed to obtain best performance. The versatility of the source is demonstrated by the production of guided beams of different molecular species.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The bending problem of a functionally graded anisotropic cantilever beam subjected to thermal and uniformly distributed load is investigated, with material parameters being arbitrary functions of the thickness coordinate. The heat conduction problem is treated as a 1D problem through the thickness. Based on the elementary formulations for plane stress problem, the stress function is assumed to be in the form of polynomial of the longitudinal coordinate variable, from which the stresses can be derived.The stress function is then determined completely with the compatibility equation and boundary conditions. A practical example is presented to show the application of the method.
ANALYTICAL SOLUTION FOR FIXED-FIXED ANISOTROPIC BEAM SUBJECTED TO UNIFORM LOAD
Institute of Scientific and Technical Information of China (English)
DING Hao-jiang; HUANG De-jin; WANG Hui-ming
2006-01-01
The analytical solutions of the stresses and displacements were obtained for fixed-fixed anisotropic beams subjected to uniform load. A stress function involving unknown coefficients was constructed, and the general expressions of stress and displacement were obtained by means of Airy stress function method. Two types of the description for the fixed end boundary condition were considered. The introduced unknown coefficients in stress function were determined by using the boundary conditions. The analytical solutions for stresses and displacements were finally obtained. Numerical tests show that the analytical solutions agree with the FEM results. The analytical solution supplies a classical example for the elasticity theory.
ON THE UNIFORM STRONG APPROXIMATION OF MARCINKIEWICZ TYPE FOR MULTIVARIABLE CONTINUOUS FUNCTIONS
Institute of Scientific and Technical Information of China (English)
Yujun Zhang; Xiaoyuan He
2005-01-01
The rate of uniform strong approximation of Marcinkiewicz type for multivariable continuous func-tions is obtained in this paper as follows:‖1/k+1 k∑j=0|Sj(f)- f|q‖≤C/k +1 k∑j=0 Eqj(f),where Sj (f) denotes the square partial Fourier sum of f and Ej (f) denotes the square best approximation of f by trigonometric polynomials of degree (j, j, … ,j),j = 0,1, 2,….
CEBAF [Continuous Electron Beam Accelerator Facility] design report
International Nuclear Information System (INIS)
This book describes the conceptual design of, and the planning for, the Continuous Electron Beam Accelerator Facility (CEBAF), which will be a high-intensity, continuous-wave electron linear accelerator (linac) for nuclear physics. Its principal scientific goal is to understand the quark structure, behavior, and clustering of individual nucleons in the nuclear medium, and simultaneously to understand the forces governing this behavior. The linac will consist of 1 GeV of accelerating structure, split into two antiparallel 0.5-GeV segments. The segments will be connected by a beam transport system to circulate the electron beams from one segment to the other for up to four complete passes of acceleration. The maximum beam energy will be 4 GeV at a design current of 200 microamperes. The accelerator complex will also include systems to extract three continuous beams from the linac and to deliver them to three experimental halls equipped with detectors and instrumentation for nuclear physics research. The accelerating structure will be kept superconducting within insulated cryostats filled with liquid helium produced at a central helium refrigerator and distributed to the cryostats via insulated transfer lines. An injector, instrumentation and controls for the accelerator, radio-frequency power systems, and several support facilities will also be provided. A cost estimate based on the Work Breakdown Structure has been completed. Assuming a five-year construction schedule starting early in FY 1987, the total estimated cost is $236 million (actual year dollars), including contingency
Directory of Open Access Journals (Sweden)
M Zahedifar
2011-06-01
Full Text Available A mixed order model is proposed for describing thermoluminescence (TL glow peaks with continuous and uniform distribution of trapping states. It is shown that the presented function reduces to the simple known models at the limiting cases. The function for TL intensity has been introduced in terms of intensity and temperature of the peak maximum. These parameters can easily be estimated from the shape of the glow peak as initial guesstimate for the curve fitting procedure. Considering the direct relation between the parameters entered in the proposed model and the physics of TL phenomenon, it is deduced that it is more appropriate for describing TL peaks with continuous distribution of trapping states.
THERMAL POST-BUCKLING OF AN ELASTIC BEAMS SUBJECTED TO A TRANSVERSELY NON-UNIFORM TEMPERATURE RISING
Institute of Scientific and Technical Information of China (English)
李世荣; 程昌钧; 周又和
2003-01-01
Based on the nonlinear geometric theory of axially extensible beams and by usingthe shooting method, the thermal post-buckling responses of an elastic beams, withimmovably simply supported ends and subjected to a transversely non-uniformly distributedtemperature rising, were investigated. Especially, the influences of the transversetemperature change on the thermal post-buckling deformations were examined and thecorresponding characteristic curves were plotted. The numerical results show that theequilibrium paths of the beam are similar to what of an initially deformed beam because ofthe thermal bending moment produced in the beam by the transverse temperature change.
SU-E-T-542: Measurement of Internal Neutrons for Uniform Scanning Proton Beams
Energy Technology Data Exchange (ETDEWEB)
Islam, M; Ahmad, S [University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Zheng, Y; Rana, S [Procure Proton Therapy Center, Oklahoma City, OK (United States); Collums, T [University of Iowa Hospitals and Clinics, Iowa City, IA (United States); Monsoon, J; Benton, E [Oklahoma State University, Stillwater, OK (United States)
2015-06-15
Purpose: In proton radiotherapy, the production of neutrons is a wellknown problem since neutron exposure can lead to increased risk of secondary cancers later in the patient’s lifetime. The assessment of neutron exposure is, therefore, important for the overall quality of proton radiotherapy. This study investigates the secondary neutrons created inside the patient from uniform scanning proton beams. Methods: Dose equivalent due to secondary neutrons was measured outside the primary field as a function of distance from beam isocenter at three different angles, 45, 90 and 135 degree, relative to beam axis. Plastic track nuclear detector (CR-39 PNTD) was used for the measurement of neutron dose. Two experimental configurations, in-air and cylindrical-phantom, were designed. In a cylindrical-phantom configuration, a cylindrical phantom of 5.5 cm diameter and 35 cm long was placed along the beam direction and in an in-air configuration, no phantom was used. All the detectors were placed at nearly identical locations in both configurations. Three proton beams of range 5 cm, 18 cm, and 32 cm with 4 cm modulation width and a 5 cm diameter aperture were used. The contribution from internal neutrons was estimated from the differences in measured dose equivalent between in-air and cylindrical-phantom configurations at respective locations. Results: The measured ratio of neutron dose equivalent to the primary proton dose (H/D) dropped off with distance and ranged from 27 to 0.3 mSv/Gy. The contribution of internal neutrons near the treatment field edge was found to be up to 64 % of the total neutron exposure. As the distance from the field edge became larger, the external neutrons from the nozzle appear to dominate and the internal neutrons became less prominent. Conclusion: This study suggests that the contribution of internal neutrons could be significant to the total neutron dose equivalent.
Wang, Lanfa
2014-01-01
This paper analyses the longitudinal space charge (LSC) impedances of a round uniform beam inside a rectangular and parallel plate chamber using image charge method. The analysis is valid for arbitrary wavelengths and the calculation converges fast. The research shows that only a few of image beams are needed to get a relative error less than 0.1%. The beam offset effect is also included.
Bang, W; Bradley, P A; Vold, E L; Boettger, J C; Fernández, J C
2015-01-01
In a recent experiment on the Trident laser facility, a laser-driven beam of quasi-monoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 eV and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable on Trident, with a finite energy spread of (delta E)/E ~ 20%, are expected to heat the targets more uniformly than a beam of 140 MeV aluminum ions with zero energy spread. The robustness of the expected heating uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.
Electron Beam Dose Distribution in the Presence of Non-Uniform Magnetic Field
Directory of Open Access Journals (Sweden)
Mohamad Javad Tahmasebi-Birgani
2014-04-01
Full Text Available Introduction Magnetic fields are capable of altering the trajectory of electron beams andcan be used in radiation therapy.Theaim of this study was to produce regions with dose enhancement and reduction in the medium. Materials and Methods The NdFeB permanent magnets were arranged on the electron applicator in several configurations. Then, after the passage of the electron beams (9 and 15 MeV Varian 2100C/D through the non-uniform magnetic field, the Percentage Depth Dose(PDDs on central axis and dose profiles in three depths for each energy were measured in a 3D water phantom. Results For all magnet arrangements and for two different energies, the surface dose increment and shift in depth of maximum dose (dmax were observed. In addition, the pattern of dose distribution in buildup region was changed. Measurement of dose profile showed dose localization and spreading in some other regions. Conclusion The results of this study confirms that using magnetic field can alter the dose deposition patterns and as a result can produce dose enhancement as well as dose reduction in the medium using high-energy electron beams. These effects provide dose distribution with arbitrary shapes for use in radiation therapy.
Continuous crafting of uniform colloidal nanocrystals using an inert-gas-driven microflow reactor
Tang, Hailong; He, Yanjie; Li, Bo; Jung, Jaehan; Zhang, Chuchu; Liu, Xiaobo; Lin, Zhiqun
2015-05-01
Recent research has witnessed rapid advances in synthesis of nanocrystals, which has led to the development of a large variety of approaches for producing nanocrystals with controlled dimensions. However, most of these techniques lack the high-throughput production. Herein, we report on a viable and robust strategy based on an inert-gas-driven microflow reactor for continuous crafting of high-quality colloidal nanocrystals. With the judicious introduction of the inert-gas driven capability, the microflow reactor provides an attractive platform for continuous production of colloidal nanocrystals in large quantities, including easily-oxidized nanocrystals. The as-synthesized nanocrystals possessed a uniform size and shape. Intriguingly, the size of nanocrystals can be effectively tailored by varying the flow rate and the precursor concentration. We envision that the microflow reactor strategy is general and offers easy access to a wide range of scalable nanocrystals for potential applications in sensors, optics, optoelectronics, solar energy conversion, batteries, photocatalysis, and electronic devices.Recent research has witnessed rapid advances in synthesis of nanocrystals, which has led to the development of a large variety of approaches for producing nanocrystals with controlled dimensions. However, most of these techniques lack the high-throughput production. Herein, we report on a viable and robust strategy based on an inert-gas-driven microflow reactor for continuous crafting of high-quality colloidal nanocrystals. With the judicious introduction of the inert-gas driven capability, the microflow reactor provides an attractive platform for continuous production of colloidal nanocrystals in large quantities, including easily-oxidized nanocrystals. The as-synthesized nanocrystals possessed a uniform size and shape. Intriguingly, the size of nanocrystals can be effectively tailored by varying the flow rate and the precursor concentration. We envision that the
Jin, Guoyong; Su, Zhu
2015-01-01
This book develops a uniform accurate method which is capable of dealing with vibrations of laminated beams, plates and shells with arbitrary boundary conditions including classical boundaries, elastic supports and their combinations. It also provides numerous solutions for various configurations including various boundary conditions, laminated schemes, geometry and material parameters, which fill certain gaps in this area of reach and may serve as benchmark solutions for the readers. For each case, corresponding fundamental equations in the framework of classical and shear deformation theory are developed. Following the fundamental equations, numerous free vibration results are presented for various configurations including different boundary conditions, laminated sequences and geometry and material properties. The proposed method and corresponding formulations can be readily extended to static analysis.
CEBAF [Continuous Electron Beam Accelerator Facility] scientific program
International Nuclear Information System (INIS)
The principal scientific mission of the Continuous Electron Beam Facility (CEBAF) is to study collective phenomena in cold (or normal) nucler matter in order to understand the structure and behavior of macroscopic systems constructed from nuclei. This document discusses in broad popular terms those issues which the CEBAF experimental and theoretical program are designed to address. Specific experimental programs currently planned for CEBAF are also reivewed. 35 refs., 19 figs
Environmental assessment: Continuous Electron Beam Accelerator Facility, Newport News, Virginia
International Nuclear Information System (INIS)
This Environmental Assessment has been prepared by the US Department of Energy (DOE) to fulfill its obligations pursuant to Sect. 102 of the National Environmental Policy Act (NEPA) of 1969 (Public Law 91-190). The proposed federal action addressed in this document is DOE's funding of a Continuous Electron Beam Accelerator Facility (CEBAF) at Newport News, Virginia. DOE intends to contract with the Southeastern Universities Research Association (SURA) for operation of CEBAF, a continuous wave (CW) linear accelerator system (linac) capable of providing high-duty-factor beams throughout the energy range from 0.5 to 4.0 GeV. CEBAF will be the first of its kind worldwide and will offer a multi-GeV energy, high-intensity, high-duty-factor electron beam for use by the US nuclear physics community in research on the states of nuclear matter and the short-distance behavior of nuclei. The CEBAF project is largely in the conceptual design stage, with some components in the preliminary design stage. Construction is anticipated to begin in 1987 and be completed by 1992
Institute of Scientific and Technical Information of China (English)
Jianqin Lü; Xiaosong Zhao
2008-01-01
Nonlinear transport of intense continuous beam in the axial-symmetric electrostatic fields is analyzed with the Lie algebraic method.The K-V particle distribution is adopted in the analysis. The results obtained can be used in the calculations of the intense continuous beam dynamics in the beam optical systems consisting of drift spaces, electrostatic lenses, and DC electrostatic accelerating tubes. A com-puter code has been designed for practical simulations. To meet the needs of accurate calculation, all the elements are divided into many small segments, the electric fields in each segment are regarded as uniform fields, and the dividing points are treated as thin lenses. Iter-ation procedures are adopted in the code to obtain self-consistent solutions. The code can be used to design low energy dc beam transport systems, electrostatic accelerators, and ion implantation machines.
Continuous variable quantum communication with bright entangled optical beams
Institute of Scientific and Technical Information of China (English)
XIE Chang-de; ZHANG Jing; PAN Qing; JIA Xiao-jun; PENG Kun-chi
2006-01-01
In this paper,we briefly introduce the basic concepts and protocols of continuous variable quantum communication,and then summarize the experimental researches accomplished by our group in this field.The main features of quantum communication systems used in our experiments are:(1) The bright entangled optical beams with the anticorrelated amplitude quadratures and the correlated phase quadratures that serve as the entanglement resources and (2) The Bell-state direct detection systems are utilized in the measurements of quantum entanglement and transmitted signals instead of the usually balanced homodyne detectors.
Acoustic Prism for Continuous Beam Steering Based on Piezoelectric Metamaterial
Xu, Jiawen
2016-01-01
This paper investigates an acoustic prism for continuous acoustic beam steering by a simple frequency sweep. This idea takes advantages of acoustic wave velocity shifting in metamaterials in the vicinity of local resonance. We apply this concept into the piezoelectric metamaterial consisting of host medium and piezoelectric LC shunt. Theoretical modeling and FEM simulations are carried out. It is shown that the phase velocity of acoustic wave changes dramatically in the vicinity of local resonance. The directions of acoustic wave can be adjusted continuously between 2 to 16 degrees by a simple sweep of the excitation frequency. Such an electro-mechanical coupling system has a feature of adjusting local resonance without altering the mechanical part of the system.
Vibration Analysis of a Simply Supported Beam Traversed by Uniform Distributed Moving Load
Institute of Scientific and Technical Information of China (English)
Yu YANG; Nian-guan TENG; Yian-feng TENG
2004-01-01
Considering the engineering background of some transportation system like maglev, vertical vibration of the simply supported beam is investigated. The length of the vehicle is assumed to be longer than the beam span. The model of moving distributed load with constant speed is established .The beam can be taken as Euler-Bernoulli beam model and the right side of the control equation is simplified by using a moving status function. Duhamel integral and mode superposition method is used to solve the dynamic behavior of the beam. In this aspect deflection and acceleration are included. The results of different parameters such as the span of beam, velocity of load and ratio vehicle-Beam masses are compared. All results show that the dynamic response of the beam is tied up with these factors: the frequency of the beam, the moving frequency of the load and the ratio of vehicle-beam mass.
On the Heat Transfer through a Solid Slab Heated Uniformly and Continuously on One of Its Surfaces
Marin, E.; Lara-Bernal, A.; Calderon, A.; Delgado-Vasallo, O.
2011-01-01
Some peculiarities of the heat transfer through a sample that is heated by the superficial absorption of light energy under continuous uniform illumination are discussed. We explain, using a different approach to that presented in a recent article published in this journal (Salazar "et al" 2010 "Eur. J. Phys." 31 1053-9), that the front surface of…
Indian Academy of Sciences (India)
V C Petwal; J N Rao; Jishnu Dwivedi; V K Senecha; K V Subbaiah
2010-03-01
A prototype pulsed electron beam irradiation facility for radiation processing of food and medical products is being commissioned at our centre in Indore, India. Analysis of surface dose and uniformity for a pulsed beam facility is of crucial importance because it is influenced by various operating parameters such as beam current, pulse repetition rate (PRR), scanning current profile and frequency, scanning width and product conveying speed. A large number of experiments are required to determine the harmonized setting of these operating parameters for achieving uniform dose. Since there is no readily available tool to set these parameters, use of Monte Carlo methods and computational tools can prove to be the most viable and time saving technique to support the assessment of the dose distribution. In the present study, Monte Carlo code, MCNP, is used to simulate the transport of 10 MeV electron beam through various mediums coming into the beam path and generate an equivalent dose profile in a polystyrene phantom for stationary state. These results have been verified with experimentally measured dose profile, showing that results are in good agreement within 4%. The Monte Carlo simulation further has been used to optimize the overlapping between the successive pulses of a scan to achieve ± 5% dose uniformity along the scanning direction. A mathematical model, which uses the stationary state data, is developed to include the effect of conveyor speed. The algorithm of the model is discussed and the results are compared with the experimentally measured values, which show that the agreement is better than 15%. Finally, harmonized setting for operating parameters of the accelerator are derived to deliver uniform surface dose in the range of 1–13 kGy/pass.
Institute of Scientific and Technical Information of China (English)
ZHANG Xiao-hua; LUO Shou-jing; DU Zhi-ming
2008-01-01
AZ91D magnesium alloy was processed by equal channel angular extrusion(ECAE). The influence of extrusion temperature, extrusion pass and extrusion route on the ultimate strength of the extruded billet was analyzed. The process of multi-pass extrusion was simulated with the method of finite element analysis, and the continuity and uniformity of effective strain in multi-pass extrusion were investigated. The results show that extrusion pass plays the most important role in improving the ultimate strength of AZ91D magnesium alloy, the extrusion route is the second, and the extrusion temperature is the last. From the numerical simulation, there exists the continuity of the accumulated deformation in multi-pass extrusion and the effective strain increases linearly. The tendency of the strain uniformity is different in multi-pass extrusion with extrusion routes. The results of experiment agree with those of numerical simulation.
Research on Shear Behavior of Reinforced Concrete Beam Under Uniform Load%均匀受力的混凝土深梁抗剪性能
Institute of Scientific and Technical Information of China (English)
刘君阳; 杨梅
2014-01-01
主要通过有限元软件模拟研究混凝土深梁在均布荷载作用下，纵筋配筋率、混凝土强度等两个因素对其抗剪性能的影响。结果表明：随着纵筋配筋率的增大，深梁的产生切应力不断减小，随着混凝土的强度的增大，深梁的产生切应变不断减小，说明纵筋配筋率和混凝土强度的增大对提高梁的抗剪性能有利。%This paper mainly through the finite element software simulation research on reinforced concrete deep beams under uniform load ,reinforcement ratio and concrete strength affect the performance of the shear .+The re-sults show that with the increase of the ratio of longitudinal reinforcement and depth ,the generation of deep beam shear stress decreases continuously ,with the increase of the strength of the concrete ,the generation of deep beam shear strain decreases constantly ,suggests that the increase of the longitudinal reinforcement reinforcement ratio and concrete strength is good for increase the shear properties of the beam .
Baier, Christel; Hermanns, Holger; Katoen, Joost-Pieter; Haverkort, Boudewijn R.
2005-01-01
A continuous-time Markov decision process (CTMDP) is a generalization of a continuous-time Markov chain in which both probabilistic and nondeterministic choices co-exist. This paper presents an efficient algorithm to compute the maximum (or minimum) probability to reach a set of goal states within a
Winter, Andreas
2016-10-01
We present a bouquet of continuity bounds for quantum entropies, falling broadly into two classes: first, a tight analysis of the Alicki-Fannes continuity bounds for the conditional von Neumann entropy, reaching almost the best possible form that depends only on the system dimension and the trace distance of the states. Almost the same proof can be used to derive similar continuity bounds for the relative entropy distance from a convex set of states or positive operators. As applications, we give new proofs, with tighter bounds, of the asymptotic continuity of the relative entropy of entanglement, E R , and its regularization {E_R^{∞}}, as well as of the entanglement of formation, E F . Using a novel "quantum coupling" of density operators, which may be of independent interest, we extend the latter to an asymptotic continuity bound for the regularized entanglement of formation, aka entanglement cost, {E_C=E_F^{∞}}. Second, we derive analogous continuity bounds for the von Neumann entropy and conditional entropy in infinite dimensional systems under an energy constraint, most importantly systems of multiple quantum harmonic oscillators. While without an energy bound the entropy is discontinuous, it is well-known to be continuous on states of bounded energy. However, a quantitative statement to that effect seems not to have been known. Here, under some regularity assumptions on the Hamiltonian, we find that, quite intuitively, the Gibbs entropy at the given energy roughly takes the role of the Hilbert space dimension in the finite-dimensional Fannes inequality.
Absence of internal tidal beams due to non-uniform stratification
Gerkema, T.; van Haren, H.
2012-01-01
A linear internal-tide generation model is applied to the Faeroe–Shetland Channel, using observed profiles of stratification. Several degrees of simplification are considered: 1) uniform, i.e. constant N; 2) vertically varying N (z); 3) the full N(x, z) and associated geostrophic background flows. I
High-frequency beam matching at the input of an ion linac with uniform spatial quadrupole focusing
International Nuclear Information System (INIS)
.There is offered a mathing device at the input of an accelerator with quadrupole spatial-uniform hiqh-frequency focusing, which removes phase dependence of the accelerator acceptance and essentially reduces the growth of the beam emittance in the acceleration process. The mathing theory is given and mathing conditions are formulated. Working ability of the smooth envelope method for the initial part of the accelerator and its applicability for investigating the coordination problems is shown. Comparison of the obtained data shows, that the effective acceptance increases approximately twice during the use of the coordinating device. For most of the input phases the acceptance becomes practically phase-independent
CEBAF [Continuous Electron Beam Accelerator Facility] design overview and project status
International Nuclear Information System (INIS)
This paper discusses the design and specifications of the Continuous Electron Beam Accelerator Facility. Beam performance objectives are discussed, as well as the recirculating linac concept, the injector, cavities, cryogenic system, beam transport and optics, rf system and construction progress. 19 refs., 10 figs
International Nuclear Information System (INIS)
Carbon and glass fiber reinforced polymer (CFRP and GFRP) are two materials suitable for strengthening the reinforced concrete (RC) beams. Although many in situ RC beams are of continuous constructions, there has been very limited research on the behavior of such beams with externally applied FRP laminate. In addition, most design guidelines were developed for simply supported beams with external FRP laminates. This paper presents an experimental program conducted to study the flexural behavior and redistribution in moment of reinforced high strength concrete (RHSC) continuous beams strengthened with CFRP and GFRP sheets. Test results showed that with increasing the number of CFRP sheet layers, the ultimate strength increases, while the ductility, moment redistribution, and ultimate strain of CFRP sheet decrease. Also, by using the GFRP sheet in strengthening the continuous beam reduced loss in ductility and moment redistribution but it did not significantly increase ultimate strength of beam. The moment enhancement ratio of the strengthened continuous beams was significantly higher than the ultimate load enhancement ratio in the same beam. An analytical model for moment-curvature and load capacity are developed and used for the tested continuous beams in current and other similar studies. The stress-strain curves of concrete, steel and FRP were considered as integrity model. Stress-strain model of concrete is extended from Oztekin et al.'s model by modifying the ultimate strain. Also, new parameters of equivalent stress block are obtained for flexural calculation of RHSC beams. Good agreement between experiment and prediction values is achieved.
Static and dynamic stability of uniform shear beam-columns under generalized boundary conditions
Dario Aristizabal-Ochoa, J.
2007-10-01
The stability and dynamic analyses (i.e., the buckling loads, natural frequencies and the corresponding modes of buckling and vibration) of a 2D shear beam-column with generalized boundary conditions (i.e., with rotational restraints and lateral bracings as well as lumped masses at both ends) and subjected to linearly distributed axial load along its span are presented in a classic manner. The two governing equations of dynamic equilibrium, that is, the classical shear-wave equation and the bending moment equation are sufficient to determine the modes of vibration and buckling, and the corresponding natural frequencies and buckling loads, respectively. The proposed model includes the simultaneous effects of shear deformations, translational and rotational inertias of all masses considered, the linearly applied axial load along the span, and the end restraints (rotational and lateral bracings at both ends). These effects are particularly important in members with limited end rotational restraints and lateral bracings. Analytical results indicate that except for members with perfectly clamped ends, the stability and dynamic behavior of shear beams and shear beam columns are governed by the bending moment equation, rather than the second-order differential equation of transverse equilibrium (or shear-wave equation). This equation is formulated in the technical literature by simple applying transverse equilibrium at both ends of the member "ignoring" the bending moment equilibrium equation. This causes erroneous results in the stability and dynamic analyses of such members with supports that are not perfectly clamped. The proposed equations reproduce as special cases: (1) the non-classical vibration modes of shear beam-columns including the inversion of modes of vibration (i.e. higher modes crossing lower modes) in members with soft end conditions, and the phenomena of double frequencies at certain values of beam slenderness ( L/ r) and (2) the phenomena of tension
MHD flow and heat transfer from continuous surface in uniform free stream of non-Newtonian fluid
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
An analysis is carried out to study the steady flow and heat transfer characteristics from a continuous flat surface moving in a parallel free stream of an electrically conducting non-Newtonian viscoelastic fluid. The flow is subjected to a transverse uniform magnetic field. The constitutive equation of the fluid is modeled by that for a second grade fluid. Numerical results are obtained for the distribution of velocity and temperature profiles. The effects of various physical parameters like viscoelastic parameter, magnetic parameter and Prandtl number on various momentum and heat transfer characteristics are discussed in detail and shown graphically.
Reduction of Non-uniform Beam Filling Effects by Vertical Decorrelation: Theory and Simulations
Short, David; Nakagawa, Katsuhiro; Iguchi, Toshio
2013-01-01
Algorithms for estimating precipitation rates from spaceborne radar observations of apparent radar reflectivity depend on attenuation correction procedures. The algorithm suite for the Ku-band precipitation radar aboard the Tropical Rainfall Measuring Mission satellite is one such example. The well-known problem of nonuniform beam filling is a source of error in the estimates, especially in regions where intense deep convection occurs. The error is caused by unresolved horizontal variability in precipitation characteristics such as specific attenuation, rain rate, and effective reflectivity factor. This paper proposes the use of vertical decorrelation for correcting the nonuniform beam filling error developed under the assumption of a perfect vertical correlation. Empirical tests conducted using ground-based radar observations in the current simulation study show that decorrelation effects are evident in tilted convective cells. However, the problem of obtaining reasonable estimates of a governing parameter from the satellite data remains unresolved.
Uniform longitudinal beam profiles in the Fermilab Recycler using adaptive rf correction
Energy Technology Data Exchange (ETDEWEB)
Hu, Martin; Broemmelsiek, Daniel Robert; Chase, Brian; Crisp, James L.; Eddy, Nathan; Joireman, Paul W.; Ng, King Yuen; /Fermilab
2007-06-01
The Fermilab Recycler Ring is a permanent magnet based 8 GeV anti-proton storage ring. A wideband RF system, driven with ARB's (ARBitrary waveform generators), allows the system to produce programmable barrier waveforms. Beam current profile distortion was observed, its origin verified both experimentally and theoretically, and an FPGA-based correction system was designed, tested and implemented to level the bunch profile.
Beam characterization of a new continuous wave radio frequency quadrupole accelerator
International Nuclear Information System (INIS)
A new Continuous Wave (CW) Radio Frequency Quadrupole (RFQ) for the ATLAS (Argonne Tandem Linac Accelerator System) Intensity Upgrade was developed, built and tested at Argonne National Laboratory. We present here a characterization of the RFQ output beam in the longitudinal phase space, as well as a measurement of the transverse beam halo. Measurement results are compared to simulations performed using the beam dynamics code TRACK. -- Highlights: • Beam commissioning of a new CW RFQ has been performed at Argonne National Laboratory. • Energy spread and bunch shape measurements were conducted. • The formation of a beam halo in the transverse phase space was studied
Continuous guided beams of slow and internally cold polar molecules
International Nuclear Information System (INIS)
In the last years we have developed a source which produces high-flux beams of electrically guided cold molecules. A molecular gas is cooled by collisions with a cryogenic buffer gas, after which an electric quadrupole guide selects slow molecules in low-field-seeking states and transports them out of the cryogenic environment. For formaldehyde we have demonstrated the high state-purity in the extracted beam by a laser-depletion experiment. As an alternative to the laser-depletion technique, we have qualitatively confirmed internal cooling for other species as well, from time-of-flight measurements obtained at different buffer-gas settings. Here, we review the source, including its technical aspects and optimization, and present its versatility from results obtained with different molecules.
Lohar, Hareram; Mitra, Anirban; Sahoo, Sarmila
2016-09-01
In the present study non-linear free vibration analysis is performed on a tapered Axially Functionally Graded (AFG) beam resting on an elastic foundation with different boundary conditions. Firstly the static problem is carried out through an iterative scheme using a relaxation parameter and later on the subsequent dynamic problem is solved as a standard eigen value problem. Minimum potential energy principle is used for the formulation of the static problem whereas for the dynamic problem Hamilton's principle is utilized. The free vibrational frequencies are tabulated for different taper profile, taper parameter and foundation stiffness. The dynamic behaviour of the system is presented in the form of backbone curves in dimensionless frequency-amplitude plane.
Grinstein, S; Boscardin, M; Christophersen, M; Da Via, C; Betta, G -F Dalla; Darbo, G; Fadeyev, V; Fleta, C; Gemme, C; Grenier, P; Jimenez, A; Lopez, I; Micelli, A; Nelist, C; Parker, S; Pellegrini, G; Phlips, B; Pohl, D L; Sadrozinski, H F -W; Sicho, P; Tsiskaridze, S
2013-01-01
Pixel detectors with cylindrical electrodes that penetrate the silicon substrate (so called 3D detectors) offer advantages over standard planar sensors in terms of radiation hardness, since the electrode distance is decoupled from the bulk thickness. In recent years significant progress has been made in the development of 3D sensors, which culminated in the sensor production for the ATLAS Insertable B-Layer (IBL) upgrade carried out at CNM (Barcelona, Spain) and FBK (Trento, Italy). Based on this success, the ATLAS Forward Physics (AFP) experiment has selected the 3D pixel sensor technology for the tracking detector. The AFP project presents a new challenge due to the need for a reduced dead area with respect to IBL, and the in-homogeneous nature of the radiation dose distribution in the sensor. Electrical characterization of the first AFP prototypes and beam test studies of 3D pixel devices irradiated non-uniformly are presented in this paper.
Energy Technology Data Exchange (ETDEWEB)
Grinstein, S., E-mail: sgrinstein@ifae.es [ICREA and Institut de Física d' Altes Energies (IFAE), Barcelona (Spain); Baselga, M. [Centro Nacional de Microelectronica, CNM-IMB (CSIC), Barcelona (Spain); Boscardin, M. [Fondazione Bruno Kessler, FBK-CMM, Trento (Italy); Christophersen, M. [U.S. Naval Research Laboratory, Washington (United States); Da Via, C. [School of Physics and Astronomy, University of Manchester, Manchester (United Kingdom); Dalla Betta, G.-F. [Universita degli Studi di Trento and INFN, Trento (Italy); Darbo, G. [INFN Sezione di Genova, Genova (Italy); Fadeyev, V. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz (United States); Fleta, C. [Centro Nacional de Microelectronica, CNM-IMB (CSIC), Barcelona (Spain); Gemme, C. [Universita degli Studi di Trento and INFN, Trento (Italy); Grenier, P. [SLAC National Accelerator Laboratory, Menlo Park (United States); Jimenez, A.; Lopez, I.; Micelli, A. [ICREA and Institut de Física d' Altes Energies (IFAE), Barcelona (Spain); Nelist, C. [INFN Sezione di Genova, Genova (Italy); Parker, S. [University of Hawaii, c/o Lawrence Berkeley Laboratory, Berkeley (United States); Pellegrini, G. [Centro Nacional de Microelectronica, CNM-IMB (CSIC), Barcelona (Spain); Phlips, B. [U.S. Naval Research Laboratory, Washington (United States); Pohl, D.-L. [University of Bonn, Bonn (Germany); Sadrozinski, H.F.-W. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz (United States); and others
2013-12-01
Pixel detectors with cylindrical electrodes that penetrate the silicon substrate (so called 3D detectors) offer advantages over standard planar sensors in terms of radiation hardness, since the electrode distance is decoupled from the bulk thickness. In recent years significant progress has been made in the development of 3D sensors, which culminated in the sensor production for the ATLAS Insertable B-Layer (IBL) upgrade carried out at CNM (Barcelona, Spain) and FBK (Trento, Italy). Based on this success, the ATLAS Forward Physics (AFP) experiment has selected the 3D pixel sensor technology for the tracking detector. The AFP project presents a new challenge due to the need for a reduced dead area with respect to IBL, and the in-homogeneous nature of the radiation dose distribution in the sensor. Electrical characterization of the first AFP prototypes and beam test studies of 3D pixel devices irradiated non-uniformly are presented in this paper.
DEFF Research Database (Denmark)
Jeong, Cheol-Ho
2010-01-01
that a test specimen was attached to a vertical surface and the floor. The frequency-dependent sound intensity distributions on absorbers were found to be affected by the reverberation chamber geometry and dimensions, the absorption capability of the specimen, and the placement of the specimen. High frequency...... sound intensity distributions on absorber under measurement conditions have been simulated using a phased beam tracing, and used as correction functions for reducing discrepancies between the measured and theoretical absorption coefficients. Two reverberation rooms were investigated by assuming...... intensity distributions above 1 kHz were similar for all studied cases, but some variations in low frequency intensity distributions were observed. If the non-uniform intensity distribution and a finite size effect are taken into account for correcting the theoretical absorption coefficients, a good...
DEFLECTION OF A HETEROGENEOUS WIDE-BEAM UNDER UNIFORM PRESSURE LOAD
Energy Technology Data Exchange (ETDEWEB)
T. V. Holschuh; T. K. Howard; W. R. Marcum
2014-07-01
Oregon State University (OSU) and the Idaho National Laboratory (INL) are currently collaborating on a test program which entails hydro-mechanical testing of a generic plate type fuel element, or generic test plate assembly (GTPA), for the purpose of qualitatively demonstrating mechanical integrity of uranium-molybdenum monolithic plates as compared to that of uranium aluminum dispersion, and aluminum fuel plates onset by hydraulic forces. This test program supports ongoing work conducted for/by the Global Threat Reduction Initiative (GTRI) Fuels Development Program. This study’s focus supports the ongoing collaborative effort by detailing the derivation of an analytic solution for deflection of a heterogeneous plate under a uniform, distributed load in order to predict the deflection of test plates in the GTPA. The resulting analytical solutions for three specific boundary condition sets are then presented against several test cases of a homogeneous plate. In all test cases considered, the results for both homogeneous and heterogeneous plates are numerically identical to one another, demonstrating correct derivation of the heterogeneous solution. Two additional problems are presents herein that provide a representative deflection profile for the plates under consideration within the GTPA. Furthermore, qualitative observations are made about the influence of a more-rigid internal fuel-meat region and its influence on the overall deflection profile of a plate. Present work is being directed to experimentally confirm the analytical solution’s results using select materials.
Beam Shaping of High-power Laser Diode Arrays by Continuous Surface-relief Elements
Ehbets, Peter; Herzig, Hans-Peter; Dändliker, René; Regnault, P.; Kjelberg, I.
2007-01-01
A breadboard for beam shaping of high-power laser diode arrays (LDAs) has been realized. The coherent beams are added with the aid of a continuous surface-relief fan-in element. It results in a nearly symmetric single lobed beam of collimated light with maximum conversion efficiency. The theoretical efficiency is determined to be 96•7%. Experimentally, one third of the total power is now in the central peak.
Study on shear strengthening of RC continuous T-beams using different layers of CFRP strips
Energy Technology Data Exchange (ETDEWEB)
Alferjani, M. B. S.; Samad, A. A. Abdul; Mohamad, Noridah [Faculty of Civil and Environmental Engineering, Universiti Tun Hussein Onn Malaysia, Batu Pahat (Malaysia); Elrawaff, Blkasem S.; Elzaroug, Omer [Faculty of Civil Engineering Omar Al Mukhtar University, Bayda, Libya, Africa (Libya)
2015-05-15
Carbon fiber reinforced polymer (CFRP) laminates are externally bonded to reinforced concrete (RC) members to provide additional strength such as flexural, shear, etc. However, this paper presents the results of an experimental investigation for enhancing the shear capacity of reinforced concrete (RC) continuous T- beams using different layers of CFRP wrapping schemes. A total of three concrete beams were tested and various sheet configurations and layouts were studied to determine their effects on ultimate shear strength and shear capacity of the beams. One beam was kept as control beams, while other beams were strengthened with externally bonded CFRP strips with three side bonding and one or two layers of CFRP strips. From the test results, it was found that all schemes were found to be effective in enhancing the shear strength of RC beams. It was observed that the strength increases with the number of sheet layers provided the most effective strengthening for RC continuous T- beam. Beam strengthened using this scheme showed 23.21% increase in shear capacity as compared to the control beam. Two prediction models available in literature were used for computing the contribution of CFRP strips and compared with the experimental results.
Study on shear strengthening of RC continuous T-beams using different layers of CFRP strips
Alferjani, M. B. S.; Samad, A. A. Abdul; Elrawaff, Blkasem S.; Elzaroug, Omer; Mohamad, Noridah
2015-05-01
Carbon fiber reinforced polymer (CFRP) laminates are externally bonded to reinforced concrete (RC) members to provide additional strength such as flexural, shear, etc. However, this paper presents the results of an experimental investigation for enhancing the shear capacity of reinforced concrete (RC) continuous T- beams using different layers of CFRP wrapping schemes. A total of three concrete beams were tested and various sheet configurations and layouts were studied to determine their effects on ultimate shear strength and shear capacity of the beams. One beam was kept as control beams, while other beams were strengthened with externally bonded CFRP strips with three side bonding and one or two layers of CFRP strips. From the test results, it was found that all schemes were found to be effective in enhancing the shear strength of RC beams. It was observed that the strength increases with the number of sheet layers provided the most effective strengthening for RC continuous T- beam. Beam strengthened using this scheme showed 23.21% increase in shear capacity as compared to the control beam. Two prediction models available in literature were used for computing the contribution of CFRP strips and compared with the experimental results.
Study on shear strengthening of RC continuous T-beams using different layers of CFRP strips
International Nuclear Information System (INIS)
Carbon fiber reinforced polymer (CFRP) laminates are externally bonded to reinforced concrete (RC) members to provide additional strength such as flexural, shear, etc. However, this paper presents the results of an experimental investigation for enhancing the shear capacity of reinforced concrete (RC) continuous T- beams using different layers of CFRP wrapping schemes. A total of three concrete beams were tested and various sheet configurations and layouts were studied to determine their effects on ultimate shear strength and shear capacity of the beams. One beam was kept as control beams, while other beams were strengthened with externally bonded CFRP strips with three side bonding and one or two layers of CFRP strips. From the test results, it was found that all schemes were found to be effective in enhancing the shear strength of RC beams. It was observed that the strength increases with the number of sheet layers provided the most effective strengthening for RC continuous T- beam. Beam strengthened using this scheme showed 23.21% increase in shear capacity as compared to the control beam. Two prediction models available in literature were used for computing the contribution of CFRP strips and compared with the experimental results
LOGICAL MATRIX FOR THE LONGITUDINAL AND TORSIONAL VIBRATIONS OF CONTINUOUS BEAMS
Directory of Open Access Journals (Sweden)
O. S. Raspopov
2008-01-01
Full Text Available The formal procedure for calculations of longitudinal and torsion vibrations of the multispan beams with continuous mass distribution on the basis of the method of start parameters, associated matrices and elements of mathematical logic is proposed.
Subsurface plasma in beam of continuous CO2-laser
Danytsikov, Y. V.; Dymshakov, V. A.; Lebedev, F. V.; Pismennyy, V. D.; Ryazanov, A. V.
1986-03-01
Experiments performed at the Institute of Atomic Energy established the conditions for formation of subsurface plasma in substances by laser radiation and its characteristics. A quasi-continuous CO2 laser emitting square pulses of 0.1 to 1.0 ms duration and 1 to 10 kW power as well as a continuous CO2 laser served as radiation sources. Radiation was focused on spots 0.1 to 0.5 mm in diameter and maintained at levels ensuring constant power density during the interaction time, while the temperature of the target surface was measured continuously. Metals, graphite and dielectric materials were tested with laser action taking place in air N2 + O2 mixtures, Ar or He atmosphere under pressures of 0.01 to 1.0 atm. Data on radiation intensity thresholds for evaporation and plasma formation were obtained. On the basis of these thresholds, combined with data on energy balance and the temperature profile in plasma layers, a universal state diagram was constructed for subsurface plasma with nonquantified surface temperature and radiation intensity coordinates.
Nonlinear FE Analysis of Reinforced H.S. Concrete Continuous Beam Strengthened with CFRP Sheet
Directory of Open Access Journals (Sweden)
Majid Mohammed Ali Kadhim
2011-01-01
Full Text Available This paper is focused on the nonlinear finite element analysis of the reinforced high strength concrete continuous beam strength with carbon fiber reinforced polymer sheet. Three full scale continuous beams are analyzed under two points load; the data of analysis are compared with the experimental data provided by Akbarzadeh and Maghsoudi [1]. ANSYS V.11 program is used in FE analysis, the results obtained from analysis give good agreement with experimental result when compared load-deflection responses, ultimate strength, and the crack patterns. The results showed that with increasing the number of layers, the ultimate strength of beams are increase by amount reached (14% for each layer. The failure mode different by increasing number of CFRP sheet layers when the beam strengthened by one layer of CFRP sheet failed by tensile rupture of CFRP sheet, and beam strengthened by more than one layer failed by intermediate crack (IC debonding of CFRP sheet.
Structural Behavior of Continuous Prestressed Steel Fiber Reinforced High Strength Concrete Beam
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The flexural behaviors of continuous fully and partially prestressed steel fiber reinforced high strength concrete beams are studied by experiment and nonlinear finite element analysis. Three levels of partial prestress ratio (PPR) are considered, and three pairs of two-span continuous beams with box sections varying in size are designed. The major parameters involved in the study include the PPR and the fiber location. It is concluded that the prestressed high strength concrete beam exhibits satisfactory ductility; the influences of steel fiber on the crack behaviors for partially prestressed beams are not as obvious as those for fully prestressed ones; steel fibers can improve the structural stiffness after cracking for fully prestressed high strength concrete beams; the moment redistribution from mid-span to intermediate support in the first stage should be mainly considered in practical design.
Finite Element Analysis of Non-uniform Beam Element Based on the MATLAB%基于MATLAB的变截面梁单元有限元分析
Institute of Scientific and Technical Information of China (English)
马志贵; 施文龙
2015-01-01
变截面梁在工程实践中被广泛应用.给出常用的梁高呈线性变化及抛物线性变化的矩形截面梁单元,根据有限元基本原理,借助于MATLAB强大的符号运算功能建立该类变截面梁单元的刚度矩阵,并给出一个变截面悬臂梁的算例,所得结果更加逼近于精确解.结果表明运用该方法可以使变截面梁的分析大大简化.%The non-uniform beam is widely used in engineering practice. This paper presents the commonly used non-uniform rectangular beam element with both linear and parabolic variation heights of the transverse section. Based on the basic principle of finite element method, by means of MATLAB powerful symbolic operation, it is convenient to establish its stiffness matrix. A non-uniform cantilever beam is presented as an example, which show that the results are more accurate solutions and the present elements can apparently simplify the analysis of non-uniform beams.
Indian Academy of Sciences (India)
GOKHAN T TAYYAR
2016-04-01
The reliability and limits of solutions for static structural analysis depend on the accuracy of the curvature and deflection calculations. Even if the material model is close to the actual material behavior, physically unrealistic deflections or divergence problems are unavoidable in the analysis if an appropriate fundamental kinematic theory is not chosen. Moreover, accurate deflection calculation plays an important role in ultimate strength analysis where in-plane stresses are considered. Therefore, a more powerful method is neededto achieve reliable deflection calculation and modeling. For this purpose, a new advanced step was developed by coupling the elasto-plastic material behavior with precise general planar kinematic analysis. The deflection is generated precisely without making geometric assumptions or using differential equations of the deflection curve. An analytical finite strain solution was derived for an elasto-plastic prismatic/non-prismatic rectangular cross-sectioned beam under a uniform moment distribution. A comparison of the analytical results with thosefrom the Abaqus FEM software package reveals a coherent correlation.
Propagation characteristics of Bessel beams generated by continuous, incoherent light sources.
Altıngöz, Ceren; Yalızay, Berna; Akturk, Selcuk
2015-08-01
We investigate the propagation behavior of Bessel beams generated by incoherent, continuous light sources. We perform experiments with narrowband and broadband light emitting diodes, and, for comparison, with a laser diode. We observe that the formation of Bessel beams is affected minimally by temporal coherence, while spatial coherence determines the longitudinal evolution of the beam profile. With spatially incoherent beams, the fringe contrast is comparable to the coherent case at the beginning of the Bessel zone, while it completely fades away by propagation, turning into a cylindrical light pipe. Our results show that beam shaping methods can be extended to cases of limited spatial coherence, paving the way for potential new uses and applications of such sources. PMID:26367302
Concept of Powerful Multistage Coaxial Cyclotron for Pulsed and Continuous Beam Production
Tumanyan, A R; Guiragossian, Z G T; Akopov, N Z
1999-01-01
The concept of large-radius multistage coaxial cyclotrons having separated orbits is described, to generate proton beams of 120-2000 MeV energy at tens of GW pulsed and hundreds of MW in continuous beam power operation. Accelerated beam losses must be less than 0.1 W/m for the intercepted average beam power linear density. The concept is inherently configured to actively compensate the longitudinal and transverse space charge expansion in beam bunches. These are based on (1) actively varying the bunch acceleration equilibrium phase while maintaining isochronism, independently for each cyclotron turns; (2) independently changing the acceleration voltage for each turn together with orbit corrections that preserve isochronism; (3) independently changing the transverse betatron oscillation tune shift, to assure non-resonant operation. Also, (4) sextupole lenses are included to compensate for chromaticity effects. Moreover, the concept is based on optimum uses of practical successful results so far achieved in bea...
Experimental study on ferritic stainless steel simply supported and continuous beams
Arrayago Luquin, Itsaso; Real Saladrigas, Esther
2015-01-01
Development of efficient design guidance for stainless steel structures is key for the increased use of this corrosion-resistant material by considering both nonlinear behaviour and strain hardening into resistance prediction expressions, together with the moment redistribution in indeterminate structures. With the aim of analysing the bending moment redistribution capacity of ferritic stainless steel beams, a comprehensive experimental programme on continuous beams is presented. These tests ...
Garcia, J B
2011-01-01
The proton beams used for the fixed target physics at the Super Proton Synchrotron (SPS) are extracted from the Proton Synchrotron ( PS) by a multiturn technique called continuous transfer (CT). During the CT extraction, large losses are observed in locations where the machine aperture should be large enough to accommodate the circulating beam. This limits the maximum intensity deliverable due to the induced stray radiation outside the PS tunnel. Scattered particles from the interaction with the electrostatic septum are identified as the possible source of these losses. This article presents a detailed study aiming to understand the origin of losses and propose possible cures. The simulations could reproduce accurately the beam loss pattern measured in real machine operation and determine the beam shaving, intrinsic to the extraction process, as the cause for the unexpected losses. Since these losses are unavoidable, the proposed solution implies a new optics scheme displacing the losses to a region with bett...
Annenkov, V. V.; Timofeev, I. V.; Volchok, E. P.
2016-05-01
In this paper, electromagnetic emissions produced in a thin beam-plasma system are studied using two-dimensional particle-in-cell simulations. For the first time, the problem of emission generation in such a system is considered in a realistic formulation allowing for the continuous injection of a relativistic electron beam through a plasma boundary. Specific attention is given to the thin plasma case in which the transverse plasma size is comparable to the typical wavelength of beam-driven oscillations. Such a case is often implemented in laboratory beam-plasma experiments and has a number of peculiarities. Emission from a thin plasma does not require intermediate generation of the electromagnetic plasma eigenmodes, as in an infinite case, and is more similar to the regular antenna radiation. In this work, we determine how efficiently the fundamental and the second harmonic emissions can be generated in previously modulated and initially homogeneous plasmas.
Holography of human pathologic specimens with continuous-beam lasers through plastination
Myers, M. Bert; Bickley, Harmon
1991-07-01
Since evaporation of cellular water leads to shrinkage and motion, holography of human tissue specimens is generally possible only with pulsed lasers. Plastination is a preservation technique in which cellular water is removed and replaced with a curable polymer. This preserves the tissue, including even the cellular anatomy, and renders the specimen rigid enough for holography with continuous beam lasers.
The Continuous Electron Beam Accelerator Facility: CEBAF at the Jefferson Laboratory
Energy Technology Data Exchange (ETDEWEB)
Leemann, Chrisoph; Douglas, David R; Krafft, Geoffrey A
2001-08-01
The Jefferson Laboratory's superconducting radiofrequency (srf) Continuous Electron Beam Accelerator Facility (CEBAF) provides multi-GeV continuous-wave (cw) beams for experiments at the nuclear and particle physics interface. CEBAF comprises two antiparallel linacs linked by nine recirculation beam lines for up to five passes. By the early 1990s, accelerator installation was proceeding in parallel with commissioning. By the mid-1990s, CEBAF was providing simultaneous beams at different but correlated energies up to 4 GeV to three experimental halls. By 2000, with srf development having raised the average cavity gradient up to 7.5 MV/m, energies up to nearly 6 GeV were routine, at 1-150 muA for two halls and 1-100 nA for the other. Also routine are beams of >75% polarization. Physics results have led to new questions about the quark structure of nuclei, and therefore to user demand for a planned 12 GeV upgrade. CEBAF's enabling srf technology is also being applied in other projects.
Energy Technology Data Exchange (ETDEWEB)
Dobranskis, R. R.; Zharkova, V. V., E-mail: valentina.zharkova@northumbria.ac.uk [Department of Mathematics and Information Sciences, University of Northumbria, Newcastle upon Tyne NE1 2XP (United Kingdom)
2014-06-10
The original continuity equation (CE) used for the interpretation of the power law energy spectra of beam electrons in flares was written and solved for an electron beam flux while ignoring an additional free term with an electron density. In order to remedy this omission, the original CE for electron flux, considering beam's energy losses in Coulomb collisions, was first differentiated by the two independent variables: depth and energy leading to partial differential equation for an electron beam density instead of flux with the additional free term. The analytical solution of this partial differential continuity equation (PDCE) is obtained by using the method of characteristics. This solution is further used to derive analytical expressions for mean electron spectra for Coulomb collisions and to carry out numeric calculations of hard X-ray (HXR) photon spectra for beams with different parameters. The solutions revealed a significant departure of electron densities at lower energies from the original results derived from the CE for the flux obtained for Coulomb collisions. This departure is caused by the additional exponential term that appeared in the updated solutions for electron differential density leading to its faster decrease at lower energies (below 100 keV) with every precipitation depth similar to the results obtained with numerical Fokker-Planck solutions. The effects of these updated solutions for electron densities on mean electron spectra and HXR photon spectra are also discussed.
GUNDOGDU, Ömer; ALNEFAIE, Khaled; DIKEN, Hamza
2014-01-01
The paper presents simulations of a continuous cantilever beam and an unbalanced disk system by extending classical Jeffcott rotor approach to a model that gives the first three (or more) modes of the flexible beam. Normal modes of a constrained structure method are used to develop the equations of motion including gyroscopic effects. Centrifugal force created by the unbalanced mass of the disk is considered as a constraint for the flexible beam. The first three modes of the flexible beam hav...
Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation
Energy Technology Data Exchange (ETDEWEB)
Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Zhang, A. L.; Chen, J. E. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)
2016-02-15
In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment.
Design, fabrication, and beam commissioning of a continuous-wave four-rod rf quadrupole
Yin, X. J.; Yuan, Y. J.; Xia, J. W.; He, Y.; Zhao, H. W.; Zhang, X. H.; Du, H.; Li, Z. S.; Li, X. N.; Jiang, P. Y.; Yang, Y. Q.; Ma, L. Z.; Wu, J. X.; Xu, Z.; Sun, L. T.; Zhang, W.; Zhang, X. Z.; Meng, J.; Zhou, Z. Z.; Yao, Q. G.; Cai, G. Z.; Lu, W.; Wang, H. N.; Chen, W. J.; Zhang, Y.; Xu, X. W.; Xie, W. J.; Lu, Y. R.; Zhu, K.; Liu, G.; Yan, X. Q.; Gao, S. L.; Wang, Z.; Chen, J. E.
2016-01-01
A new heavy-ion linac within a continuous-wave (CW) 4-rod radio-frequency quadrupole (RFQ) was designed and constructed as the injector for the separated-sector cyclotron (SSC) at the Heavy Ion Research Facility at Lanzhou (HIRFL). In this paper, we present the development of and the beam commissioning results for the 53.667 MHz CW RFQ. In the beam dynamics design, the transverse phase advance at zero current, σ0 ⊥ , is maintained at a relatively high level compared with the longitudinal phase advance (σ0 ∥ ) to avoid parametric resonance. A quasi-equipartitioning design strategy was applied to control the emittance growth and beam loss. The installation error of the electrodes was checked using a FARO 3D measurement arm during the manufacturing procedure. This method represents a new approach to measuring the position shifts of electrodes in a laboratory environment and provides information regarding the manufacturing quality. The experimental results of rf measurements exhibited general agreement with the simulation results obtained using CST code. During on-line beam testing of the RFQ, two kinds of ion beams (40Ar 8 + and 16O5+ ) were transported and accelerated to 142.8 keV /u , respectively. These results demonstrate that the SSC-Linac has made a significant progress. And the design scheme and technology experiences developed in this work can be applied to other future CW RFQs.
Experimental generation of frequency-tunable entangled optical beams with continuous variables
Institute of Scientific and Technical Information of China (English)
Zhihui Yan; Yana Shang; Xiaojun Jia; Changde Xie
2011-01-01
Frequency tunable continuous variable (CV) entangled optical beams are experimentally demonstrated from a non-degenerate optical parametric oscillator working above the threshold. The measured correlation variances of amplitude and phase quadratures are 3.2 and 1.5 dB, respectively, below the corresponding shot noise level (SNL) in the tuning range of 580 GHz (2.25 nm). The frequency tuning is realized by simply controlling the temperature of the nonlinear crystal.%@@ Frequency tunable continuous variable (CV) entangled optical beams are experimentally demonstrated from a non-degenerate optical parametric oscillator working above the threshold.The measured correlation variances of amplitude and phase quadratures are 3.2 and 1.5 dB, respectively, below the corresponding shot noise level (SNL) in the tuning range of 580 GHz (2.25 nm).The frequency tuning is realized by simply controlling the temperature of the nonlinear crystal.
Yanqin Wang; Mingbo Pu; Zuojun Zhang; Xiong Li; Xiaoliang Ma; Zeyu Zhao; Xiangang Luo
2015-01-01
Two-dimensional metasurface has attracted growing interest in recent years, owing to its ability in manipulating the phase, amplitude and polarization state of electromagnetic wave within a single interface. However, most existing metasurfaces rely on the collective responses of a set of discrete meta-atoms to perform various functionalities. In this paper, we presented a quasi-continuous metasurface for high-efficiency and broadband beam steering in the microwave regime. It is demonstrated b...
Mass flow prediction of the coriolis meter using C0 continuous beam elements
Binulal, B. R.; Rajan, Akash; Abhilash, Suryan R.; Kochupillai, Jayaraj; Kim, Heuy Dong
2015-06-01
A three node C0 continuous isoparametric beam element is formulated to model the curved pipe conveying fluid in three dimensional configuration. The equations of motion for the combined structure and fluid domain including added mass effect, Coriolis effect, centrifugal effect and the effect of pressure on the walls of pipe have been developed by Paidoussis. This equation is converted to finite element formulation using Galerkin technique and is validated with the results available from literature.
International Nuclear Information System (INIS)
The Ac Stark effect and the effect of laser beam non-uniformity on the two-photon resonant three-photon ionization spectrum of cesium is investigated. The non-uniformity due to the temporal and the spatial variations of the pumping laser makes the ionization spectrum non-symmetric and shifts the peak frequency of the excited-state population from the peak frequency of the ionization yield. The order of the non-linearity of the ionization process is also studied near resonances, and it is found that the minimum of the curve is close to the peak frequency of the excited-state spectrum. Ways of applying these results to studies of autoionizing states are suggested
Springett, J. C.
The technique outlined in this paper is intended to eliminate the problems of cochannel interference and uniform geographic distribution of user channels which arise in conventional designs for a multiple spot beam communication satellite to serve mobile telephony users across the CONUS. By time multiplexing FM/FDMA signal ensembles so that only those beams operating on distinct frequency subbands are allowed to transmit concurrently, cochannel interference arising from simultaneous frequency subband reuse is precluded. Thus, time disjoint frequency reuse is accomplished over a repetitive sequence of fixed time slots. By assigning different size subbands to each time slot, a market of nonuniform users can be accommodated. The technique results in a greatly simplified antenna feed system design for the satellite, at a cost of imposing the need for time slot synchronization on the mobile FM receivers whose ability for rejecting adjacent channel interference is somewhat diminished.
Wang, Yanqin; Pu, Mingbo; Zhang, Zuojun; Li, Xiong; Ma, Xiaoliang; Zhao, Zeyu; Luo, Xiangang
2015-12-01
Two-dimensional metasurface has attracted growing interest in recent years, owing to its ability in manipulating the phase, amplitude and polarization state of electromagnetic wave within a single interface. However, most existing metasurfaces rely on the collective responses of a set of discrete meta-atoms to perform various functionalities. In this paper, we presented a quasi-continuous metasurface for high-efficiency and broadband beam steering in the microwave regime. It is demonstrated both in simulation and experiment that the incident beam deviates from the normal direction after transmitting through the ultrathin metasurface. The efficiency of the proposed metasurface approximates to the theoretical limit of the single-layer metasurface in a broad frequency range, owing to the elimination of the circuit resonance in traditional discrete structures. The proposed scheme promises potential applications in broadband electromagnetic modulation and communication systems, etc.
Wang, Yanqin; Pu, Mingbo; Zhang, Zuojun; Li, Xiong; Ma, Xiaoliang; Zhao, Zeyu; Luo, Xiangang
2015-01-01
Two-dimensional metasurface has attracted growing interest in recent years, owing to its ability in manipulating the phase, amplitude and polarization state of electromagnetic wave within a single interface. However, most existing metasurfaces rely on the collective responses of a set of discrete meta-atoms to perform various functionalities. In this paper, we presented a quasi-continuous metasurface for high-efficiency and broadband beam steering in the microwave regime. It is demonstrated both in simulation and experiment that the incident beam deviates from the normal direction after transmitting through the ultrathin metasurface. The efficiency of the proposed metasurface approximates to the theoretical limit of the single-layer metasurface in a broad frequency range, owing to the elimination of the circuit resonance in traditional discrete structures. The proposed scheme promises potential applications in broadband electromagnetic modulation and communication systems, etc. PMID:26635228
Interference of Backscatter from Two Droplets in a Focused Continuous Wave CO2 Doppler Lidar Beam
Jarzembski, Maurice A.; Srivastava, Vandana
1999-01-01
Interference due to the superposition of backscatter, beta, from two micron-sized droplets using a NASA/MSFC cw (continuous wave) CO2 Doppler lidar at 9.1 micrometer wavelength was detected for the first time. The resultant single beta signal from both droplets contained an interference structure with a well-defined periodicity which was accurately measured and compared with cw lidar theory. The agreement between measurements and theory is excellent, indicating that the interference arises because the droplets are moving at different speeds and, therefore, the relative droplet separation is not constant. This gives the superimposed beta signal from both droplets in the lidar beam moving in and out of constructive and destructive interference with a well-defined periodic structure. A measurement of a time-resolved signal pulse with an oscilloscope of the combined from two approx. 14.12 micrometers in diameter silicone oil droplets responding to the Gaussian lidar beam intensity at the lidar beam focus is shown. Full details of this laboratory experimental setup, particle generation method, measurement technique, and the cw lidar can be found elsewhere. The stream of silicone oil droplets resided at a Doppler-shift center frequency of f (sub D) approx. (3.4 plus or minus 0.2) MHz, giving droplet speed v approx.(21.9 plus or minus 1.3) ms (exp. -1). Also shown on a separate channel is the corresponding signature using an amplitude demodulator circuit designed to detect the amplitude envelope of f(sub D) within the pulse profile. beta from simultaneous droplet events show a complete cyclic interference structure of maximum and minimum. The average period T of the complete cycle of interference is 13.02 plus or minus.39 microseconds. Toward the right edge of the profile, the interference disappears because one of the droplets is leaving the lidar beam while the other one remains in the beam, thus, giving beta for a single droplet.
Economic and education impact of building the Continuous Electron Beam Accelerator Facility
International Nuclear Information System (INIS)
The Continuous Electron Beam Accelerator Facility (CEBAF) was built in Newport News, Virginia, between 1987 and 1995 and is a new basic research laboratory christened the Thomas Jefferson National Accelerator Facility (Jefferson Lab). Jefferson Lab's science and technology mission has major economic and educational benefits: basic research discoveries, improvement and application of key technologies associated with the accelerator and the experiments, extensive subcontracting with industry, and diverse employment and educational opportunities. The $600 million invested by federal, state, local and international partners to build Jefferson Lab has had substantial economic and educational benefits locally, as well as significant benefits distributed among industries and universities throughout the United States
International Nuclear Information System (INIS)
This report contains papers from a summer workshop of the continuous electron beam accelerator facility. Some topics of these papers are: spectrometers; electron scattering from deuterons; relativistic correlations in nuclear matter; pion production on 3He and 3H; quantum electrodynamic processes in crystals; 12C(e,e'p) x reaction; deuteron polarization tensor and relativistic spin rotation; electromagnetic excitation of nuclei; electron distortion and structure functions in (e,e'p) reactions; and reaction mechanism of 4He(e,e'p)3H
Production of multi-, oligo- and single-pore membranes using a continuous ion beam
Apel, P. Yu.; Ivanov, O. M.; Lizunov, N. E.; Mamonova, T. I.; Nechaev, A. N.; Olejniczak, K.; Vacik, J.; Dmitriev, S. N.
2015-12-01
Ion track membranes (ITM) have attracted significant interest over the past two decades due to their numerous applications in physical, biological, chemical, biochemical and medical experimental works. A particular feature of ITM technology is the possibility to fabricate samples with a predetermined number of pores, including single-pore membranes. The present report describes a procedure that allowed for the production of multi-, oligo- and single-pore membranes using a continuous ion beam from an IC-100 cyclotron. The beam was scanned over a set of small diaphragms, from 17 to ∼1000 μm in diameter. Ions passed through the apertures and impinged two sandwiched polymer foils, with the total thickness close to the ion range in the polymer. The foils were pulled across the ion beam at a constant speed. The ratio between the transport speed and the scanning frequency determined the distance between irradiation spots. The beam intensity and the aperture diameters were adjusted such that either several, one or no ions passed through the diaphragms during one half-period of scanning. After irradiation, the lower foil was separated from the upper foil and was etched to obtain pores 6-8 μm in diameter. The pores were found using a color chemical reaction between two reagents placed on opposite sides of the foil. The located pores were further confirmed using SEM and optical microscopy. The numbers of tracks in the irradiation spots were consistent with the Poisson statistics. Samples with single or few tracks obtained in this way were employed to study fine phenomena in ion track nanopores.
The influence of physical wedges on penumbra and in-field dose uniformity in ocular proton beams.
Baker, Colin; Kacperek, Andrzej
2016-04-01
A physical wedge may be partially introduced into a proton beam when treating ocular tumours in order to improve dose conformity to the distal border of the tumour and spare the optic nerve. Two unwanted effects of this are observed: a predictable broadening of the beam penumbra on the wedged side of the field and, less predictably, an increase in dose within the field along a relatively narrow volume beneath the edge (toe) of the wedge, as a result of small-angle proton scatter. Monte Carlo simulations using MCNPX and direct measurements with radiochromic (GAFCHROMIC(®) EBT2) film were performed to quantify these effects for aluminium wedges in a 60 MeV proton beam as a function of wedge angle and position of the wedge relative to the patient. For extreme wedge angles (60° in eye tissue) and large wedge-to-patient distances (70 mm in this context), the 90-10% beam penumbra increased from 1.9 mm to 9.1 mm. In-field dose increases from small-angle proton scatter were found to contribute up to 21% additional dose, persisting along almost the full depth of the spread-out-Bragg peak. Profile broadening and in-field dose enhancement are both minimised by placing the wedge as close as possible to the patient. Use of lower atomic number wedge materials such as PMMA reduce the magnitude of both effects as a result of a reduced mean scattering angle per unit energy loss; however, their larger physical size and greater variation in density are undesirable. PMID:26988936
Helicopter downwash measured by continuous-wave Doppler lidars with agile beam steering
DEFF Research Database (Denmark)
Sjöholm, Mikael; Angelou, Nikolas; Hansen, Per;
2012-01-01
A ground-based remote sensing short-range WindScanner with agile beam steering based on a modified ZephIR continuous-wave wind lidar (LIght Detection And Ranging) and a double prism arrangement has recently been developed at the Department of Wind Energy at the DTU Risø campus. The WindScanner me......A ground-based remote sensing short-range WindScanner with agile beam steering based on a modified ZephIR continuous-wave wind lidar (LIght Detection And Ranging) and a double prism arrangement has recently been developed at the Department of Wind Energy at the DTU Risø campus. The Wind......Scanner measures the line-of-sight component of the wind and by rapid steering of the line-of-sight and the focus position, all locations within a cone with a full top angle of 120 can be reached from about 8 meters out to some hundred meters depending on the range resolution needed. By using three such Wind...
Energy Technology Data Exchange (ETDEWEB)
Cons Perez, N.; Gomez Gonzalez, N.; Garcia Repiso, S.; Hernandez Rodriguez, J.; Montes Fuentes, C.; Garcia Ledesma, J.; Diez Gallego, M. A.
2015-07-01
One of the latest advances in PET scanners is the introduction of acquisitions with continuous movement of stretcher (CBM) Among the benefits that this technology brings they are: lower axial variation of noise, greater flexibility in planning studies with different levels of statistics for different anatomical and greater patient comfort regions. Behavior unexpected because the concentration obtained in all CBMs studies with PET-CT scanner Biograph mCTFlow (Slemens Medica Solutions) we propose a quantitative analysis with a series of parameters chosen to assess the inhomogeneity between cuts in the concentration obtained by homogeneous mannequins. A comparison with studies of static bed (S and S) indicates a problem only mode dynamic bed. (Author)
Fonteyne, Margot; Vercruysse, Jurgen; De Leersnyder, Fien; Besseling, Rut; Gerich, Ad; Oostra, Wim; Remon, Jean Paul; Vervaet, Chris; De Beer, Thomas
2016-09-01
This study focuses on the twin screw granulator of a continuous from-powder-to-tablet production line. Whereas powder dosing into the granulation unit is possible from a container of preblended material, a truly continuous process uses several feeders (each one dosing an individual ingredient) and relies on a continuous blending step prior to granulation. The aim of the current study was to investigate the in-line blending capacity of this twin screw granulator, equipped with conveying elements only. The feasibility of in-line NIR (SentroPAT, Sentronic GmbH, Dresden, Germany) spectroscopy for evaluating the blend uniformity of powders after the granulator was tested. Anhydrous theophylline was used as a tracer molecule and was blended with lactose monohydrate. Theophylline and lactose were both fed from a different feeder into the twin screw granulator barrel. Both homogeneous mixtures and mixing experiments with induced errors were investigated. The in-line spectroscopic analyses showed that the twin screw granulator is a useful tool for in-line blending in different conditions. The blend homogeneity was evaluated by means of a novel statistical method being the moving F-test method in which the variance between two blocks of collected NIR spectra is evaluated. The α- and β-error of the moving F-test are controlled by using the appropriate block size of spectra. The moving F-test method showed to be an appropriate calibration and maintenance free method for blend homogeneity evaluation during continuous mixing. PMID:27543030
Continuous electropolishing of Hastelloy substrates for ion-beam assisted deposition of MgO
Energy Technology Data Exchange (ETDEWEB)
Kreiskott, Sascha; Arendt, Paul N; Bronisz, Lawrence E; Foltyn, Steve R; Matias, Vladimir [Superconductivity Technology Center, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2003-05-01
We demonstrate the applicability of continuous electropolishing for the preparation of metal tapes for ion-beam assisted deposition of MgO for the fabrication of in-plane textured template layers. These templates are used for the fabrication of second generation high temperature superconducting wires utilizing YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} coatings on metallic substrates. Surface roughness values below 1 nm and local slopes of less than 1 deg. could be achieved with the electropolishing process. Mean surface roughness values are lower with the use of electropolishing and slopes of surface roughness inclines are significantly reduced compared to the best results of mechanical polishing (3.5 nm and 5 deg., respectively). The cost-effective process of electropolishing shows great promise for the fabrication of second generation high temperature superconducting wire.
Continuous electropolishing of Hastelloy substrates for ion-beam assisted deposition of MgO
International Nuclear Information System (INIS)
We demonstrate the applicability of continuous electropolishing for the preparation of metal tapes for ion-beam assisted deposition of MgO for the fabrication of in-plane textured template layers. These templates are used for the fabrication of second generation high temperature superconducting wires utilizing YBa2Cu3O7-δ coatings on metallic substrates. Surface roughness values below 1 nm and local slopes of less than 1 deg. could be achieved with the electropolishing process. Mean surface roughness values are lower with the use of electropolishing and slopes of surface roughness inclines are significantly reduced compared to the best results of mechanical polishing (3.5 nm and 5 deg., respectively). The cost-effective process of electropolishing shows great promise for the fabrication of second generation high temperature superconducting wire
Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun
2016-01-01
Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations. PMID:27386838
Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun
2016-07-01
Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations.
Takada, Kazumasa; Yasuno, Takahiro
2016-05-20
We describe theoretically and experimentally how valuable information on the distributed Brillouin spectra of an optical waveguide is derived from the stationary Brillouin grating measurement under uniform pumping over the waveguide by using the coherent frequency-modulated continuous wave reflectometry. We upconvert the frequencies of the probe and pumping light waves by the Brillouin frequency with one modulator and detect the Stokes light in the same way that we detect the Fresnel and Rayleigh backreflections in the fiber. The intrinsic coherent spike is reduced by using the lock-in detection and the least squares method to reveal the distributed Brillouin spectra of a short optical fiber consisting of two different fibers spliced together. PMID:27411124
Deceleration of a continuous-wave(CW)molecular beam with a single quasi-CW semi-Gaussian laser beam
Institute of Scientific and Technical Information of China (English)
Yin Ya-Ling; Xia Yong; Yin Jian-Ping
2008-01-01
We propose a promising scheme to decelerate a CW molecular beam by using a red-detuned quasi-cw semi-Gaussian laser beam(SGB).We study the dynamical process of the deceleration for a CW deuterated ammonia(ND3)molecular beam by Monte-Carlo simulation method.Our study shows that we can obtain a ND3 molecular beam with a relative average kinetic energy loss of about 10% and a relative output molecular number of more than 90% by using a single quasi-cw SGB with a power of 1.5kW and a maximum optical well depth of 7.33mK.
Tarasenko, Victor F.; Rybka, Dmitrii V.; Baksht, Evgenii H.; Kostyrya, Igor'D.; Lomaev, Mikhail I.
2008-01-01
The gas diode current-voltage characteristics at the voltage pulses applied from the RADAN and SM-3NS pulsers, and generation of an supershort avalanche electron beam (SAEB) have been studied experimentally in an inhomogeneous electric field upon a nanosecond breakdown in an air gap at atmospheric pressure. Displacement currents with amplitude over 1 kA have been observed and monitored. It is shown that the displacement current amplitude gets increased due to movement of the dense plasma front and charging of a "capacitor" formed between plasma and anode. The SAEB generation time relatively to the discharge current pulses and the gap voltage were determined in the experiments. It is shown that the SAEB current maximum at the pulser voltages of hundreds kV is registered on the discharge current pulse front, before the discharge current peak of the gas diode capacitance, and the delay time of these peaks is determined by the value of an interelectrode spacing. The delay time in case of a gap of 16 mm and air breakdown at atmospheric pressure was ~100 ps, and in case of 10 mm it was less than 50 ps.
Energy Technology Data Exchange (ETDEWEB)
Spata, Michael F. [JLAB
2014-12-01
Jefferson Lab has recently completed the accelerator portion of the 12 GeV Upgrade for the Continuous Electron Beam Accelerator Facility. All 52 SRF cryomodules have been commissioned and operated with beam. The initial beam transport goals of demonstrating 2.2 GeV per pass, greater than 6 GeV in 3 passes to an existing experimental facility and greater than 10 GeV in 5-1/2 passes have all been accomplished. These results along with future plans to commission the remaining beamlines and to increase the performance of the accelerator to achieve reliable, robust and efficient operations at 12 GeV are presented.
Zharkova, V. V.; Dobranskis, R. R.
2016-06-01
In this paper we consider simultaneous analytical solutions of continuity equations for electron beam precipitation (a) in collisional losses and (b) in ohmic losses, or mixed energy losses (MEL) by applying the iterative method to calculate the resulting differential densities at given precipitation depth. The differential densities of precipitating electrons derived from the analytical solutions for MELs reveal increased flattening at energies below 10-30 keV compared to a pure collisional case. This flattening becomes stronger with an increasing precipitation depth turning into a positive slope at greater precipitation depths in the chromosphere resulting in a differential density distribution with maximum that shifts towards higher energies with increase in column depth, while the differential densities combining precipitating and returning electrons are higher at lower energies than those for a pure collisional case. The resulting hard X-ray (HXR) emission produced by the beams with different initial energy fluxes and spectral indices is calculated using the MEL approach for different ratios between the differential densities of precipitating and returning electrons. The number of returning electrons can be even further enhanced by a magnetic mirroring, not considered in the present model, while dominating at lower atmospheric depths where the magnetic convergence and magnitude are the highest. The proposed MEL approach provides an opportunity to account simultaneously for both collisional and ohmic losses in flaring events, which can be used for a quick spectral fitting of HXR spectra and evaluation of a fraction of returning electrons versus precipitating ones. The semi-analytical MEL approach is used for spectral fitting to Reuven High Energy Solar Spectroscopic Imager observations of nine C, M and X class flares revealing a close fit to the observations and good resemblance to numerical FP solutions.
Yoshioka, Yasuo; Suzuki, Osamu; Nishimura, Kazuo; Inoue, Hitoshi; Hara, Tsuneo; Yoshida, Ken; Imai, Atsushi; Tsujimura, Akira; Nonomura, Norio; Ogawa, Kazuhiko
2012-01-01
We aimed to analyse late toxicity associated with external beam radiation therapy (EBRT) for prostate cancer using uniform dose-fractionation and beam arrangement, with the focus on the effect of 3D (CT) simulation and portal field size. We collected data concerning patients with localized prostate adenocarcinoma who had been treated with EBRT at five institutions in Osaka, Japan, between 1998 and 2006. All had been treated with 70 Gy in 35 fractions, using the classical 4-field technique wit...
Energy Technology Data Exchange (ETDEWEB)
Kurosu, K [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Department of Medical Physics ' Engineering, Osaka University Graduate School of Medicine, Osaka (Japan); Takashina, M; Koizumi, M [Department of Medical Physics ' Engineering, Osaka University Graduate School of Medicine, Osaka (Japan); Das, I; Moskvin, V [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States)
2014-06-01
Purpose: Monte Carlo codes are becoming important tools for proton beam dosimetry. However, the relationships between the customizing parameters and percentage depth dose (PDD) of GATE and PHITS codes have not been reported which are studied for PDD and proton range compared to the FLUKA code and the experimental data. Methods: The beam delivery system of the Indiana University Health Proton Therapy Center was modeled for the uniform scanning beam in FLUKA and transferred identically into GATE and PHITS. This computational model was built from the blue print and validated with the commissioning data. Three parameters evaluated are the maximum step size, cut off energy and physical and transport model. The dependence of the PDDs on the customizing parameters was compared with the published results of previous studies. Results: The optimal parameters for the simulation of the whole beam delivery system were defined by referring to the calculation results obtained with each parameter. Although the PDDs from FLUKA and the experimental data show a good agreement, those of GATE and PHITS obtained with our optimal parameters show a minor discrepancy. The measured proton range R90 was 269.37 mm, compared to the calculated range of 269.63 mm, 268.96 mm, and 270.85 mm with FLUKA, GATE and PHITS, respectively. Conclusion: We evaluated the dependence of the results for PDDs obtained with GATE and PHITS Monte Carlo generalpurpose codes on the customizing parameters by using the whole computational model of the treatment nozzle. The optimal parameters for the simulation were then defined by referring to the calculation results. The physical model, particle transport mechanics and the different geometrybased descriptions need accurate customization in three simulation codes to agree with experimental data for artifact-free Monte Carlo simulation. This study was supported by Grants-in Aid for Cancer Research (H22-3rd Term Cancer Control-General-043) from the Ministry of Health
Environmental Management Assessment of the Continuous Electron Beam Accelerator Facility (CEBAF)
International Nuclear Information System (INIS)
This report documents the results of the Environmental Management Assessment performed at the Continuous Electron Beam Accelerator Facility (CEBAF) in Newport News, Virginia. During this assessment, activities and records were reviewed and interviews were conducted with personnel from the CEBAF Site Office; the CEBAF management and operating contractor (M ampersand O), Southeastern Universities Research Association, Inc. (SURA); the Oak Ridge Field Office (OR); and the responsible DOE Headquarters Program Office, the Office of Energy Research (ER). The onsite portion of the assessment was conducted from March 8 through March 19, 1993, by the US Department of Energy's (DOE's) Office of Environmental Audit (EH-24) located within the office of Environment, Safety and Health (EH). DOE 5482.1 B, ''Environment, Safety and Health Appraisal Program,'' and Secretary of Energy Notice (SEN)-6E-92, ''Departmental Organizational and Management Arrangements,'' establish the mission of EH-24 to provide comprehensive, independent oversight of Department-wide environmental programs on behalf of the Secretary of Energy. The ultimate goal of EH-24 is enhancement of environmental protection and minimization of risk to public health and the environment. EH-24 accomplishes its mission utilizing systematic and periodic evaluations of the Department's environmental programs within line organizations, and through use of supplemental activities which serve to strengthen self-assessment and oversight functions within program, field, and contractor organizations
Institute of Scientific and Technical Information of China (English)
Hong Yuan; Zifeng Lin
2009-01-01
Fiber reinforced polymer (FRP) composites are increasingly being used for the re-pair and strengthening of deteriorated concrete structural components through adhesive bonding of prefabricated strips/plates and the wet lay-up of fabric. Interracial bond failure modes have at-tracted the attention of researchers because of the importance. The objective of the present study is to analyse the interface failure mechanism of reinforced concrete continuous beam strength-ened by FRP. An analytical solution has been firstly presented to predict the entire debonding process of the model. The realistic bi-linear bond-slip interfacial law was adopted to study this problem. The crack propagation process of the loaded model was divided into four stages (elastic, elastic-softening, elastic-softening-debonded and softening-debonded stage). Among them, elastic-softening-debonded stage has four sub-stages. The equations are solved by adding suitable stress and displacement boundary conditions. Finally, critical value of bond length is determined to make the failure mechanism in the paper effective by solving the simultaneously linear algebraic equations. The interaction between the upper and lower FRP plates can be neglected if axial stiffness ratio of the concrete-to-plate prism is large enough.
Kobayashi, H
1999-01-01
Two practically useful quantities have been introduced to characterize a continuous-energy-spectrum neutron beam and to describe transmission phenomena of the beam in the field of quantitative neutron radiography. These quantities are the effective energy instead of a peak energy or a mean energy of the spectrum and an effective total macroscopic (ETM) cross section instead of a total macroscopic (TM) cross section as defined for a monochromatic energy. Four neutron beams have been used to measure ETM cross sections at effective energies of 29.8, 17.2, 9.8 meV, and at the In resonance energy of 1.46 eV. Results are studied as a function of estimated effective energy, where the effective energy was estimated by a beam quality indicator (BQI) which has been proposed recently. Validity of ETM cross sections as a function of the effective energy is discussed and correlated with recent nuclear data.
Continuous-Wave Laser Beam Fanning in Organic Solutions: A Novel Phenomenon
Abdeldayem, Hossin; Witherow, William K.; Shields, Angela; Penn, Benjamin; Frazier, Donald O.; Moghbel, Mehdi; Venkateswarlu, P.; Sekhar, P. Chandra; George, M. C.
1994-01-01
If a low-power cw Ar(+) laser beam (approx. 50 mW) is sent horizontally and focused on the entrance side of a cuvette containing an absorptive solution, the beam fans into the lower half of the cuvette instead of propagating through and forming self-phase-modulation fringes. We call this phenomenon self-beam fanning, which has been observed in several organic solutions. We present here several experimental results and a descriptive model of the phenomenon.
International Nuclear Information System (INIS)
In this work, measurements of epitaxial growth rate transients for multiple quantum wells (MQWs) in chemical beam epitaxy (CBE) have been made. Mass spectrometry measurements of typical growth conditions were made of gas source species of the InAsxP1-x/InP system, while reflection high-energy electron diffraction (RHEED) measurements were made for the GaAs/AlxGa1-xAs and InxGa1-xAs/GaAs systems. The results of these experiments went directly into predicting the transient growth rate of thin layers for multi-quantum well photovoltaic devices. The data obtained using these techniques resulted in an improved growth interruption sequence for MQW structures in the InAsxP1-x/InP system. Improvements in overall material quality have been observed by high resolution X-ray diffraction (HRXRD). HRXRD measurements of the InAsxP1-x/InP structures yield sharp satellite peaks revealing the possibility of achieving nearly perfect interfaces. From low temperature photoluminescence, narrow emission linewidths from quantum wells indicate an enhanced compositional uniformity, and room temperature photocurrent spectroscopy reveals an improvement in device performance
Interference of Backscatter from Two Droplets in a Focused Continuous-Wave CO2 Doppler Lidar Beam
Jarzembski, Maurice A.; Srivastava, Vandana
1999-01-01
With a focused continuous-wave CO2 Doppler lidar at 9.1-microns wavelength, the superposition of backscatter from two approximately 14.12-micron-diameter silicone oil droplets in the lidar beam produced interference that resulted in a single backscatter pulse from the two droplets with a distinct periodic structure. This interference is caused by the phase difference in backscatter from the two droplets while they are traversing the lidar beam at different speeds, and thus the droplet separation is not constant. The complete cycle of interference, with periodicity 2(pi), gives excellent agreement between measurements and lidar theory.
Wang, Aichen; Lu, Renfu; Xie, Lijuan
2016-01-01
Spatially resolved spectroscopy provides a means for measuring the optical properties of biological tissues, based on analytical solutions to diffusion approximation for semi-infinite media under the normal illumination of an infinitely small light beam. The method is, however, prone to error in measurement because the actual boundary condition and light beam often deviate from that used in deriving the analytical solutions. It is therefore important to quantify the effect of different boundary conditions and light beams on spatially resolved diffuse reflectance in order to improve the measurement accuracy of the technique. This research was aimed at using finite element method (FEM) to model light propagation in turbid media, subjected to normal illumination by a continuous-wave beam of infinitely small or finite size. Three types of boundary conditions [i.e., partial current (PCBC), extrapolated (EBC), and zero (ZBC)] were evaluated and compared against Monte Carlo (MC) simulations, since MC could provide accurate fluence rate and diffuse reflectance. The effect of beam size was also investigated. Overall results showed that FEM provided results as accurate as those of the analytical method when an appropriate boundary condition was applied. ZBC did not give satisfactory results in most cases. FEM-PCBC yielded a better fluence rate at the boundary than did FEM-EBC, while they were almost identical in predicting diffuse reflectance. Results further showed that FEM coupled with EBC effectively simulated spatially resolved diffuse reflectance under the illumination of a finite size beam. A large beam introduced more error, especially within the region of illumination. Research also confirmed an earlier finding that a light beam of less than 1 mm diameter should be used for estimation of optical parameters. FEM is effective for modeling light propagation in biological tissues and can be used for improving the optical property measurement by the spatially resolved
Institute of Scientific and Technical Information of China (English)
Shang Ya-Na; Yan Zhi-Hui; Jia Xiao-Jun; Su Xiao-Long; Xie Chang-De
2011-01-01
The influence of the extra classical noises in seed beams on the entanglement between the signal and the idler modes of the output fields generated by a non-degenerate optical parametric amplifier operating at deamplification is investigated theoretically and experimentally. With the increase of the extra classical noises in the seed beams, the correlation degree of the output entangled optical fields, which is scaled by the quantum noise limit, decreases rapidly. The experimental results are in good agreement with the theoretical calculations.
International Nuclear Information System (INIS)
This work study the resolution of Warren and X-trussed continuous beams using equivalent stiffness coefficients and moments of inertia. The equilibrium equations in the generic Joint r are obtained by finite differences method and the deflections and arbitrary static load equations are present in finite Fourier series form. The results of illustrative examples for both kinds of trussed be beams are compared with solutions obtained with the Lorane Linear Program. The influence of panels number and comparisions with classic result of equivalent inertia are established. Abacus for X-trussed beams for stiffness coefficients obtained by series versus equivalent inertia stiffness coefficients and corrections using the top and bottom chords area are presented. (Author)
Topologies of (strong) uniform convergence on bornologies
Holá, Lubica; Novotný, Branislav
2012-01-01
We continue the study of topologies of strong uniform convergence on bornologies initiated in [G. Beer and S. Levi, Strong uniform continuity, J. Math Anal. Appl., 350:568-589, 2009] and [G. Beer and S. Levi, Uniform continuity, uniform convergence and shields, Set-Valued and Variational Analysis, 18:251-275, 2010]. We study cardinal invariants of topologies of (strong) uniform convergence on bornologies on the space of continuous real-valued functions and we also generalize some known result...
Institute of Scientific and Technical Information of China (English)
ZHAO xiao-Song; L(U) Jian-Qin
2009-01-01
Both the PIC(Particle-In-Cell) model and the Lie algebraic method can be used to simulate the transport of intense continuous beams.The PIC model is to calculate the space charge field,which is blended into the external field,and then simulate the trajectories of particles in the total field;the Lie algebraic method is to simulate the intense continuous beam transport with transport matrixes.Two simulation codes based on the two methods are developed respectively,and the simulated results of transport in a set of electrostatic lenses are compared.It is found that the results from the two codes are in agreement with each other.and both approaches have their own merits.
Institute of Scientific and Technical Information of China (English)
杨骁; 蔡赟姝
2008-01-01
Nonlinear bending of cantilever incompressible poroelastic beams subjected to a uniform load is investigated with the constraint that fluid flow is only in the axial direction. The governing equations for large deflection of the poroelastic beam are derived from theory of incompressible saturated porous media. Then, nonlinear responses of a cantilever beam with impermeable fixed end and permeable free end are examined with the Galerkin truncation method. The deflections and bending moments of the poroelastie beam and the equivalent couples of the pore fluid pressures are shown in figures. The differences of the results between the large deflection and the small deflection theories are analyzed. It is shown that the results of the large deflection theory are smaller than those of the small deflection theory, and the time needed to approach their stationary states for the large deflection theory is shorter than that for the small deflection theory.
Institute of Scientific and Technical Information of China (English)
刘波; 王有志; 胡朋; 袁泉
2015-01-01
To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.
Thermionic gun control system for the CEBAF [Continuous Electron Beam Accelerator Facility] injector
International Nuclear Information System (INIS)
The injector for the CEBAF accelerator must produce a high-quality electron beam to meet the overall accelerator specifications. A Hermosa electron gun with a 2 mm-diameter cathode and a control aperture has been chosen as the electron source. This must be controlled over a wide range of operating conditions to meet the beam specifications and to provide flexibility for accelerator commissioning. The gun is controlled using Computer Automated Measurement and Control (CAMAC IEEE-583) technology. The system employs the CAMAC-based control architecture developed at CEBAF. The control system has been tested, and early operating data on the electron gun and the injector beam transport system has been obtained. This system also allows gun parameters to be stored at the operator location, without paralyzing operation. This paper describes the use of this computer system in the control of the CEBAF electron gun. 2 refs., 6 figs., 1 tab
The CEBAF [Continuous Electron Beam Accelerator Facility] superconducting accelerator: An overview
International Nuclear Information System (INIS)
The CEBAF accelerator is a CW linac based on rf superconductivity and making use of multiple recirculation. Its major components are a 50 MeV injector, two linac segments of 0.5 GeV energy gain each, and recirculator arcs connecting the two linac segments. Each linac segment consists of 25 cryomodules, separated by warm sections with quadrupoles, steering magnets, and beam diagnostics. Each cryomodule contains 8, 1500 MHz, 5-cell, Cornell type cavities with waveguide couplers for fundamental power and HOM damping, each cavity being powered by its own klystron. Recirculator arcs are vertically stacked, large radius, strong focusing beam lines that minimize synchrotron radiation effects. A high quality (ΔE/E ∼ 10-4, ε ∼ 10-9 m) beam of 200μA, 100% duty factor, with 0.5 GeV ≤ E ≤ 4.0 GeV will be generated
Melikhov, Sergey A
2011-01-01
Although topological and uniform approaches to foundations of what was then known as Analysis Situs originated in the same works by M. Frechet and F. Riesz, uniform spaces hopelessly lagged behind in development, and were never taken seriously in algebraic and geometric topology, due in part to the lack of a coherent theory of quotient spaces, and of a reasonable notion of a polyhedron in the uniform category. Yet there are painful side effects of the usual topological foundations: for instance, the non-metrizability of the cone over the real line, and the non-metrizability of RP^\\infty (as a CW-complex or as the geometric realization of a simplicial set). We show that (the topology of) quotient uniformity is, after all, far nicer than quotient topology in the context of metrizable spaces, and that (metrizable, possibly locally infinite-dimensional) uniform polyhedra do exist - and behave nicely - which appears to provide a satisfactory solution to an old open-ended problem by Isbell.
Finite element modeling of light propagation in fruit under illumination of continuous-wave beam
Spatially-resolved spectroscopy provides a means for measuring the optical properties of biological tissues, based on analytical solutions to diffusion approximation for semi-infinite media under the normal illumination of infinitely small size light beam. The method is, however, prone to error in m...
Azimi, Mohammadamin; Bin Adnan, Azlan; Sam, Abdul Rahman Bin Mohd; Tahir, Mahmood Md; Faridmehr, Iman; Hodjati, Reza
2014-01-01
The seismic performance of RC columns could be significantly improved by continuous spiral reinforcement as a result of its adequate ductility and energy dissipation capacity. Due to post-earthquake brittle failure observations in beam-column connections, the seismic behaviour of such connections could greatly be improved by simultaneous application of this method in both beams and columns. In this study, a new proposed detail for beam to column connection introduced as "twisted opposing rectangular spiral" was experimentally and numerically investigated and its seismic performance was compared against normal rectangular spiral and conventional shear reinforcement systems. In this study, three full scale beam to column connections were first designed in conformance with Eurocode (EC2-04) for low ductility class connections and then tested by quasistatic cyclic loading recommended by ACI Building Code (ACI 318-02). Next, the experimental results were validated by numerical methods. Finally, the results revealed that the new proposed connection could improve the ultimate lateral resistance, ductility, and energy dissipation capacity. PMID:25309957
Directory of Open Access Journals (Sweden)
Mohammadamin Azimi
2014-01-01
Full Text Available The seismic performance of RC columns could be significantly improved by continuous spiral reinforcement as a result of its adequate ductility and energy dissipation capacity. Due to post-earthquake brittle failure observations in beam-column connections, the seismic behaviour of such connections could greatly be improved by simultaneous application of this method in both beams and columns. In this study, a new proposed detail for beam to column connection introduced as “twisted opposing rectangular spiral” was experimentally and numerically investigated and its seismic performance was compared against normal rectangular spiral and conventional shear reinforcement systems. In this study, three full scale beam to column connections were first designed in conformance with Eurocode (EC2-04 for low ductility class connections and then tested by quasistatic cyclic loading recommended by ACI Building Code (ACI 318-02. Next, the experimental results were validated by numerical methods. Finally, the results revealed that the new proposed connection could improve the ultimate lateral resistance, ductility, and energy dissipation capacity.
Tests on ferritic stainless steel simply supported and continuous SHS and RHS beams
Arrayago Luquin, Itsaso; Real Saladrigas, Esther; Mirambell Arrizabalaga, Enrique
2015-01-01
Development of efficient design guidance for stainless steel structures is key for the spreading of this corrosion-resistant material by considering both nonlinear behavior and strain hardening into predicting expressions, together with allowing the consideration of moment redistribution in indeterminate structures. With the aim of analyzing the bending moment redistribution capacity in ferritic stainless steel beams (RHS and SHS), an experimental programme is presented. The tests contribute ...
Niobium thermal - mechanical treatment produced by continuously cast ingots and electron beam fusion
International Nuclear Information System (INIS)
Continuonsly cast Nb ingots produced in Brazil by electron beam fusion have been thermally-mechanically processed. These ingots were subjected to a pre-deformation between 0 to 50%, and subsequently treated thermally between 900 to 18000C for 2,3 and 4 hours. Grain refinement was attained by further reduction in area deformations between 42 to 96%, followed by thermal treatments for 3 hours between 810 to 13000C. The results material exhibited an equiaxial grain structure of 50 μm and was tensile tested. These tensile results are compared to the results for niobium produced by traditional commercial practices. (Author)
Fu, Chunyu
2015-03-01
During the service life of bridges, cracks can easily occur due to the dynamic loadings acting on them. These cracks may seriously affect the safety and serviceability of the bridges. Thus, this paper investigates the effect of these cracks on the vibration of a continuous beam bridge subjected to moving vehicles. The cracks are simulated by switching cracks, which can open and close fully instantaneously, and the beam behavior is considered as a sequence of linear states, each of which can be evaluated through a modal analysis. Special attention is paid to the analysis of the instant of crack switching, the linkage point of two adjacent linear states. The mode shapes and equation of motion corresponding to the new state after the switching are determined first. Next, the responses at the switching instant are recalculated. Finally, the beam displacement can be obtained by taking these responses as the initial condition. A numerical method is applied to investigate the validity of the proposed method, and the results show that the crack switching can result in higher accelerations, alter the slopes of the modal contributions to the displacement, and produce a new peak in the displacement history. During the resonance caused by a series of vehicles, the switching can reduce the first modal contribution to the resonance, but increase the second modal contribution. As a result, the resonant amplitude becomes smaller and the resonant mode changes.
连续梁墩柱合理设计的影响因素分析%Factor Analysis of Continuous Beam Pier Columns Rational Design
Institute of Scientific and Technical Information of China (English)
张帅; 肖锋文; 赵杰丽
2012-01-01
随着连续梁桥的广泛应用,连续梁桥墩柱的合理设计值得深入研究.从影响连续梁桥墩柱设计的主要因素出发,深入分析各影响因素的重要性,为连续梁桥墩柱合理设计提供参考.%With the wide application of the continuous beam bridge, the rational design of continuous beam pier column worthy of further study. In this article, starting from the main factors affecting the continuous beam bridge pier column design. In-depth analysis of the importance of each factor in order to give reference for the rational design of continuous beam bridge pier column.
International Nuclear Information System (INIS)
The design of the CEBAF accelerator system is based upon a multipass racetrack configuration, the straight sections of which will utilize 1497-MHz superconducting linac sections with independent magnetic transport at the end of each linac segment. Room temperature SW rf separators operating at a frequency of 998 MHz will be used in each independent transport channel at one end of the racetrack to extract a portion of the recirculating current. With the frequency chosen and appropriate phasing, three independent beams of correlated energy may be extracted for use in the three experimental areas. The design of the rf separators, abased on an alternating periodic structure (APS), will be described and some preliminary prototype cold test results will be given. 11 refs., 10 figs., 2 tabs
Ko, Kwang-Hoon; Kim, Yonghee; Park, Hyunmin; Cha, Yong-Ho; Kim, Taek-Soo; Lee, Lim; Lim, Gwon; Han, Jaemin; Ko, Kwang-Hee; Jeong, Do-Young
2015-08-01
Continuous-wave single-frequency tunable 544- and 272-nm beams have been demonstrated by the second- and fourth-harmonic conversions of a 1088-nm fundamental beam from a diode-oscillator fiber-amplifier. The single-pass second-harmonic generation with a MgO-doped periodically poled stoichiometric LiTaO3 crystal and the external-cavity frequency-doubling technique with a bulk BBO crystal were employed to achieve an approximately 6-W 544-nm beam and a 1.5-W 272-nm beam, respectively. We characterized the second- and fourth-harmonic generations and discussed their applications to calcium spectroscopy.
CEBAF [Continuous Electron Beam Accelerator Facility] superconducting cavity rf drive system
International Nuclear Information System (INIS)
The CEBAF rf system consists of 418 individual rf amplifier chains. Each superconducting cavity is phase locked to the master drive reference line to within 1 degree, and the cavity field gradient is regulated to within 1 part in 104 by a state-of-the-art rf control module. Precision, continuously adjustable, modulo 3600 phase shifters are used to generate the individual phase references, and a compensated rf detector is used for level feedback. The close coupled digital system enhances system accuracy, provides self-calibration, and continuously checks the system for malfunction. Calibration curves, the operating program, and system history are stored in an on board EEPROM. The rf power is generated by a 5kW, water cooled, permanent magnet focused klystron. The klystrons are clustered in groups of 8 and powered from a common supply. rf power is transmitted to the accelerator sections by semiflexible waveguide
International Nuclear Information System (INIS)
The planned experimental program at CEBAF includes high-resolution, large acceptance spectrometers and a large toroidal magnetic, detector. In order to take full advantage of the high quality beam characteristics, the performances required will make these devices quite unique instruments compared to existing facilities in the same energy range. Preliminary designs have shown that such performances can be reached, but key questions concerning design concepts and most appropriate and cost-effective technologies had to be answered before going further with the designs. It was the purpose of the Workshop on CEBAF Spectrometer Magnet Design and Technology, organized by the CEBAF Research and Engineering Divisions, to provide the most complete information about the state-of-the-art tools and techniques in magnet design and construction and to discuss the ones most appropriate to the CEBAF spectrometers. In addition, it is expected that this Workshop will be the staring point for further interactions and collaborations between international magnet experts and the CEBAF staff, during the whole process of designing and building the spectrometers
DEFF Research Database (Denmark)
Blasques, José Pedro Albergaria Amaral; Stolpe, Mathias
2011-01-01
and cross section geometry. The resulting finite element matrices are significantly smaller than those obtained using equivalent finite element models. This modeling approach is therefore an attractive alternative in computationally intensive applications at the conceptual design stage where the focus...... is on the global structural response. An optimization strategy is presented which aims at enabling the use of fiber angles as continuous design variables albeit the problems may have many local minima. A sequence of closely related problems with an increasing number of design variables is treated. The design found...
Zhang, Rui; Jia, Huaiting; Tian, Xiaocheng; Yuan, Haoyu; Zhu, Na; Su, Jingqin; Hu, Dongxia; Zhu, Qihua; Zheng, Wanguo
2016-10-01
In the research of inertial confinement fusion, laser plasma interaction (LPI) is becoming a key problem that affects ignition. Here, multi-frequency modulation (Multi-FM) smoothing by spectral dispersion (SSD), continuous phase plate (CPP) and polarization smoothing (PS) were experimentally studied and implemented on the SG-III laser facility. After using these techniques, the far field distribution of SG-Ⅲ laser facility can be adjusted, controlled and repeated accurately. The output spectrums of the cascade phase modulators used for Multi-FM SSD were stable and the FM-to-AM effect can be restrained. Experiments on SG-III laser facility indicate that when the number of color cycles adopts 1, imposing SSD with 3.3 times diffraction limit (TDL) did not lead to pinhole closure in the spatial filters of preamplifier and main amplifiers with 30-TDL pinhole size. The nonuniformity of the focal spots using Multi-FM SSD, CPP and PS drops to 0.18, comparing to 0.26 with CPP+SSD, 0.57 with CPP+PS and 0.84 with only CPP and wedged lens. Polarization smoothing using flat birefringent plate in the convergent beam of final optics assembly (FOA) was studied. The PS plates were manufactured and equipped on SG-III laser facility for LPI research. Combined beam smoothing and polarization manipulation were also studied to solve the LPI problem. Results indicate that through adjusting dispersion directions of SSD beams in a quad, two dimensional SSD can be obtained. Using polarization control plate (PCP), polarization on the near field and far field can be manipulated, providing new method to solve LPI problem in indirect drive laser fusion.
Kurkin, S. A.; Koronovski, A. A.; Hramov, A. E.
2009-08-01
Results are presented from a numerical study of the effect of an external magnetic field on the conditions and mechanisms for the formation of a virtual cathode in a relativistic electron beam. Characteristic features of the nonlinear dynamics of an electron beam with a virtual cathode are considered when the external magnetic field is varied. Various mechanisms are investigated by which the virtual cathode oscillations become chaotic and their spectrum becomes a multifrequency spectrum, thereby complicating the dynamics of the vircator system. A general mechanism for chaotization of the oscillations of a virtual cathode in a vircator system is revealed: the electron structures that form in an electron beam interact by means of a common space charge field to give rise to additional internal feedback. That the oscillations of a virtual cathode change from the chaotic to the periodic regime is due to the suppression of the mechanism for forming secondary electron structures.
Energy Technology Data Exchange (ETDEWEB)
Kurosu, Keita [Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Takashina, Masaaki; Koizumi, Masahiko [Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Das, Indra J. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Moskvin, Vadim P., E-mail: vadim.p.moskvin@gmail.com [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States)
2014-10-01
Although three general-purpose Monte Carlo (MC) simulation tools: Geant4, FLUKA and PHITS have been used extensively, differences in calculation results have been reported. The major causes are the implementation of the physical model, preset value of the ionization potential or definition of the maximum step size. In order to achieve artifact free MC simulation, an optimized parameters list for each simulation system is required. Several authors have already proposed the optimized lists, but those studies were performed with a simple system such as only a water phantom. Since particle beams have a transport, interaction and electromagnetic processes during beam delivery, establishment of an optimized parameters-list for whole beam delivery system is therefore of major importance. The purpose of this study was to determine the optimized parameters list for GATE and PHITS using proton treatment nozzle computational model. The simulation was performed with the broad scanning proton beam. The influences of the customizing parameters on the percentage depth dose (PDD) profile and the proton range were investigated by comparison with the result of FLUKA, and then the optimal parameters were determined. The PDD profile and the proton range obtained from our optimized parameters list showed different characteristics from the results obtained with simple system. This led to the conclusion that the physical model, particle transport mechanics and different geometry-based descriptions need accurate customization in planning computational experiments for artifact-free MC simulation.
Institute of Scientific and Technical Information of China (English)
范胜君; 江龙
2011-01-01
This paper establishes an existence and uniqueness result for the solution to a one-dimensional backward stochastic differential equation (BSDE for short) whose generator satisfies Constantin's condition in y and is uniformly continuous in z, which generalizes some known results.%建立了关于一维倒向随机微分方程(简写为BSDE)的一个存在唯一性结果,其中BSDE的生成元g关于y满足Constantin条件,关于z是一致连续的.这改进了一些已知结果.
Energy Technology Data Exchange (ETDEWEB)
Lee, Jung Eui; Yeo, Tae Jung; Oh, Kyu Hwan; Yoon, Jong Kyu [School of Materials Science and Engineering, Seoul Nat`l Univ., Seoul (Korea, Republic of); Han, Heung Nam [Oxford Center for Advanced Materials and Composites, Department of Materials, Univ. of Oxford (United Kingdom)
1997-12-31
A mathematical model for a coupled analysis of fluid flow, heat transfer and deformation behavior in the continuously cast beam blank has been developed. The fluid flow, heat transfer and solidification in the mold region were analyzed with 3-dimensional finite difference method (FDM) based on control volume method. A body fitted coordinate system was introduced for the complex geometry of the beam blank. The effects of turbulence and natural convection of molten steel were taken into account in determining the fluid flow in the strand. The thermo-elasto-plastic deformation behavior in the cast strand and the formation of air gap between the solidifying shell and the mold were analyzed by the finite element method (FEM) using the 2-dimensional slice temperature profile calculated by the FDM. The heat flow between the strand and the mold was evaluated by the coupled analysis between the fluid flow-heat transfer analysis and the thermo-elasto-plastic stress analysis. In order to determine the solid fraction in the mushy zone, the microsegregation of solute element was assessed. The effects of fluid flow on the heat transfer, the solidification of steel and the distribution of shell thickness during the casting of the beam blank were simulated. The deformation behavior of the solidifying shell and the possibility of cracking of the strand were also investigated. The recirculating flows were developed in the regions of the web and the flange tip. The impinging of the inlet flow from the nozzle retarded the growing of solidifying shell in the regions of the fillet and the flange. The air gap between the strand and the mold was formed near the region of the corner of the flange tip. At the initial stage of casting, the probability of the surface cracking was high in the regions of the fillet and the flange tip. After the middle stage of casting, the internal cracking was predicted in the regions of the flange tip, and between the fillet and the flange tip. (author) 38
Evaluation on imaging uniformity of Varian 23 EX cone-beam CT%Varian23EX加速器附加锥形束CT图像均匀性分析
Institute of Scientific and Technical Information of China (English)
张俊; 徐利明; 刘晖; 李炜澔; 全红
2011-01-01
目的 分析Varian 23 EX加速器附加KV X线锥形束CT(CBCT)在不同扫描条件下图像均匀性的变化.方法 采用安装在直线性加速器上的CBCT系统,在标准头/体部扫描条件下重复扫描体模,并将数据通过放疗网络传至计划系统及Matlab 7.0,利用Eclips计划系统评价获取图像在x、y及z轴方向上的均匀性变化,并与传统扇形束CT(FBCT)扫描重建图像的测量结果进行比较.结果 CBCT图像在标准头/体部扫描条件下,在三个轴向上均有良好的对称性和均匀性.在标准头部扫描方式下CT值的波动范围分别为:x轴士25 HU,y轴士30 HU,z轴士20 HU.在标准体部扫描模式下,CT值的波动范围略大.等中心横断面x,y轴方向上具有最佳的对称性和均匀性.相对于x,y轴方向,z轴具有更佳的对称性和均匀性.Bowtie滤过器能够明显减少模体散射线,可提高图像的均匀性.结论 Varian 23 EX加速器附加KV X线CBCT图像均匀度好,通过对CT值校正,CBCT可以用于治疗计划系统的剂量计算.%Objective To analyze the variation of image quality in the domain of the uniformity while the scanning conditions of KV X-ray cone-beam CT (CBCT) was fixed on the Varian 23 EX linear accelerator. Methods Under the standard head/body part term, the phantom was successively scanned using CBCT fixed on the linear accelerator. The data were delivered to the TPS and Matlab 7. 0 software via the radiotherapy network. The variation of imaging qualities in the domain of the uniformity on the x, y and z axis were obtained using the Eclips TPS evaluation. Then the results were compared with those obtained by the scanning reconstruction images of traditional fan-beam CT (FBCT). Results The images of CBCT under the standard head/body part term had favorable symmetry and uniformity on the x, y and z axis. Under the standard head part term, the spatial fluctuant CT value ranges were ±25 HU on the x axis, ±30 HU on the y axis and ± 20 HU on
Directory of Open Access Journals (Sweden)
Ping Lou
2008-01-01
Full Text Available In the finite element method, there are shortcomings using the conventional formulae to calculate the sectional forces, i.e., the bending moment and the shear force, at any cross-section of Bernoulli-Euler beam under dynamic loads. This paper presents some new finite-element formulae overcoming the shortcomings of the conventional ones to calculate the sectional forces at any cross-section of a Bernoulli-Euler beam on continuously viscoelastic foundation subjected to concentrated moving loads. The proposed formulae can easily degenerate into the formulae for calculating the sectional forces of a simply supported or a continuous Bernoulli-Euler beam subjected to concentrated moving loads, and into the formulae for calculating the sectional forces of a Bernoulli-Euler beam on Winkler foundation under static loads. Five numerical examples including static and dynamic analyses are chosen to illustrate the application of the proposed formulae. Numerical results show: (1 compared with the conventional formulae, the proposed formulae can improve the calculation accuracy of the sectional forces of beam; (2 one should use the proposed formulae, not the conventional formulae, to calculate the sectional forces at any cross-section in Bernoulli-Euler beam.
Energy Technology Data Exchange (ETDEWEB)
Brasiliano, Andrea E-mail: andrea@unb.br; Doz, Graciela N. E-mail: raciela@unb.br; Brito, Jose Luis V. de E-mail: jlbrito@unb.br
2004-01-01
In general, the structures are submitted during their useful life to deterioration processes that, depending on the intensity, may affect their performance and load capacity and consequently their safety. In this case, it s necessary to accomplish an inspection in order to evaluate the conditions f the structure and to locate and quantify the intensity of the damage. In his study, a method to identify and to quantify damage in structures, called Residual Error Method in the Movement Equation [Localizacao e quantificacao e danos em estruturas por meio de suas caracteristicas dinamicas. niversidade de Brasilia, Brasilia, DF, 2000] is evaluated, by a numerical analysis, to verify its efficiency when applied to continuous beams and frame structures. This method is based on the alteration, produced by damage, in he dynamic properties of the structures. The location of the damage is done observing the error in the movement equation of the intact structures. The structures are discretized in finite elements and the damage is introduced by stiffness and area reduction of the elements' cross-sections. Other two methods of damage detection used in this paper are: the Damage Detection from changes in Curvature Mode Shapes [J. Sound Vibration 145 (1991) 321] and the indexes MAC [Proc. 1st Int. Modal Anal. Conf. 1 (1982) 110] and COMAC [Proc. 6th Int. Modal Anal. Conf. 1 (1988) 690]. Observing the obtained results, the Residual Error Method in the Movement Equation is efficient in the damage location and quantification of the studied structures.
Becerra, Daniel L.; Kuritzky, Leah Y.; Nedy, Joseph; Saud Abbas, Arwa; Pourhashemi, Arash; Farrell, Robert M.; Cohen, Daniel A.; DenBaars, Steven P.; Speck, James S.; Nakamura, Shuji
2016-02-01
Continuous-wave blue semipolar ( 20 2 ¯ 1 ¯ ) III-nitride laser diodes were fabricated with highly vertical, smooth, and uniform mirror facets produced by chemically assisted ion beam etching. Uniform mirror facets are a requirement for accurate experimental determination of internal laser parameters, including internal loss and injection efficiency, which were determined to be 9 cm-1 and 73%, respectively, using the cavity length dependent method. The cavity length of the uncoated devices was varied from 900 μm to 1800 μm, with threshold current densities ranging from 3 kA/cm2 to 9 kA/cm2 and threshold voltages ranging from 5.5 V to 7 V. The experimentally determined internal loss was found to be in good agreement with a calculated value of 9.5 cm-1 using a 1D mode solver. The loss in each layer was calculated and in light of the analysis several modifications to the laser design are proposed.
Energy Technology Data Exchange (ETDEWEB)
Piermattei, A.; Azario, L.; Arcovito, G. [Universita Cattolica S Cuore. Rome (Italy). Ist. di Fisica; Toni, M.P. [Ente Nazionale per l`Energia Elettrica, Rome (Italy)
1996-06-01
The large range of reference air kerma rates of brachytherapy sources involves the use of large-volume ionization chambers. When such ionization chambers are used the ion-recombination correction factor k{sub sat} has to be determined. In this paper three spherical ion chambers with volume ranging from 30 to 10{sup 4} cm{sup 3} have been irradiated by photons of a {sup 192}Ir source to determine the k{sub sat} factors. The ionization currents of the ion chambers as a function of the applied voltage and the air kerma rate have been analysed to determine the contribution of the initial and general ion recombination. The k{sub sat} values for large-volume ionization chambers obtained by considering the general ion recombination as predominant (Almond`s approach) are in disagreement with the results obtained using methods that consider both initial and general ion-recombination contributions (Niatel`s approach). Such disagreement can reach 0.7% when high currents are measured for a high-activity source calibration in terms of reference air kerma rate. In this study a new `two-voltage` method, independent of the voltage ratio given by a dosimetry system, is proposed for practical dosimetry of continuous x-and gamma-radiation beams. In the case where the Almond approach is utilized, the voltage ratio V{sub 1}/V{sub 2} should be less than 2 instead of Almond`s limit of V{sub 1}/V{sub 2} <5. (Author).
Bracco, C; Presland, A; Redaelli, S; Sarchiapone, L; Weiler, T
2007-01-01
A single sided mobile graphite diluter block TCDQ, in combination with a two-sided secondary collimator TCS and an iron shield TCDQM, will be installed in front of the superconducting quadrupole Q4 magnets in IR6, in order to protect it and other downstream LHC machine elements from destruction in the event of a beam dump that is not synchronised with the abort gap. The TCDQ will be positioned close to the beam, and will intercept the particles from the secondary halo during low beam lifetime. Previous studies (1-4) have shown that the energy deposited in the Q4 magnet coils can be close to or above the quench limit. In this note the results of the latest FLUKA energy deposition simulations for Beam 2 are described, including an upgrade possibility for the TCDQ system with an additional shielding device. The results are discussed in the context of the expected performance levels for the different phases of LHC operation.
Enhanced temperature uniformity by tetrahedral laser heating
Schroers, Jan; Bossuyt, Sven; Rhim, Won-Kyu; Li, Jianzhong; Zhou, Zhenhua; Johnson, William L.
2004-01-01
emperature profile on a spherical sample that is heated by laser beams in various geometries while processed in vacuum is analyzed. Sample heating by one or four laser beams was considered. An analytical expression was derived for directional sample heating cases. It suggests an enhanced temperature uniformity over the samples when heated with four diffuse laser beams arranged in a tetrahedral geometry. This was experimentally verified by heating a spherical stainless steel sample by laser be...
Saranath, K. M.; Ramji, M.
2015-05-01
Joining of materials using welding results in the formation of material zones with varying microstructure across the weld. Extraction of the mechanical properties of those individual heterogeneous zones are important in designing components and structures comprised of welds. In this study, the zone wise local extraction of the elastic and plastic properties of an electron beam welded Ti-6Al-4V titanium alloy has been carried out using both the uniform stress method (USM) and the virtual fields method (VFM) involving digital image correlation (DIC) technique. The surface strain field obtained using DIC technique from a transverse weld specimen tensile testing is used for extracting the zone wise strain evolution. Initially, using uniform stress assumption, zone wise full range stress-strain curves are extracted. In USM methodology, the elastic and plastic material models are fitted to the zone wise stress-strain curves and required parameters are extracted from it. But inherent disadvantage is lot of images need to be processed for the parameter extraction. Recently, VFM is gaining lot of popularity in characterization domain as it is robust, accurate and faster. VFM is based on the principle of virtual work where, the weak form of local equilibrium equations and kinematically admissible virtual displacement fields are utilized for parameter extraction. Hollomon's power law is used here as the hardening rule. Young's modulus, Poisson's ratio, yield stress, strength coefficient and strain hardening exponent are the parameters extracted zone wise using both USM and VFM. A Vicker's microhardness measurement is also conducted across the weld zone towards mapping the strength behavior. Fusion zone has reported higher yield strength, strength coefficient and Poisson's ratio. Young's modulus value is found decreasing from base metal towards the fusion zone. The trend observed in parameter variation across the weld zone obtained by both USM and VFM compares very well. Due
预应力损失对连续梁桥内力的影响%Impacts of prestress loss on internal force of continuous beam bridge
Institute of Scientific and Technical Information of China (English)
曾辉; 杨凡坤
2012-01-01
Integrating with three-span continuous beam bridge on the extra large（48＋80＋48）m bridge,this paper discusses two conditions with and without considering prestress loss,introduces the composition and calculation method of prestress loss,and studies the impacts of prestress loss on internal force of continuous beam bridge,which has provided theoretical guidance for the design and calculation of three-span continuous beam bridge.%结合广东某特大桥（48＋80＋48）m三跨连续梁,从考虑和不考虑预应力损失两种情况进行了论述,介绍了预应力损失的组成和计算方法,进行了预应力损失对桥梁结构内力影响的研究,为三跨连续梁桥设计计算提供了理论指导。
Institute of Scientific and Technical Information of China (English)
杨建中
2012-01-01
The theory and solution for inventive problems--TRIZ is briefly introduced including the core theory, two kinds of methods for analyzing the technical problems and five kinds of tools for solving the technical problems. The non-uniform of crystal product size with continuous process is analyzed and studied with the physical contradiction method and technical contradiction method of TRIZ, the solutions for problems are put forward.%对技术发明理论和方法体系——TRIZ作了简要介绍，阐述了TRIZ的核心理论、TRIZ分析技术问题的2种方法和TRIZ解决技术问题的5种工具。针对连续法生产中普遍存在的结晶产品颗粒不均匀问题，运用TRIZ中的物理矛盾法和技术矛盾法进行了分析研究，提出了解决问题的方法。
Lajimi, Seyed Amir Mousavi
2014-01-01
The nonlinear dynamics of a microbeam-rigid body gyroscope are investigated by using a continuation method. To study the nonlinear dynamics of the system, the Lagrangian of the system is discretized and the reduced-order model is obtained. By using the continuation method, the frequency-response curves are computed and the stability of response is determined.
Institute of Scientific and Technical Information of China (English)
Y．P．Du; J．W．Yang; R．Shi; X．C．Cui
2004-01-01
According to turbulent theory and characteristics of beam blank continuous casting, 3-Dmodel to represent the flow of beam blank mould is established. The predicted results indicate that the exit obliquity of up 15°(+15°) should be adopted, which will benefit the floatation of non-metallic inclusion and purification of the molten steel. When the nozzle angle is 120°, the flow pattern is reasonable. Proper nozzle depth can be 200mm. Turbulent kinetic of meniscus can be reduced by adopting the square nozzle and suitable area of side outlet when casting speed increases. The results are consistent with those of water model experiment, so the model is exact and reasonable. The model can provide important information for design of SEN and defining of immersion depth.
Should Students Wear Uniforms?
Cohn, Carol A.; Siegel, Loren
1996-01-01
Two essays present opposing viewpoints on school uniforms. One suggests that uniforms make safer schools and better students. The other states that teenagers will rebel, and the uniform debate is a diversion from more pressing problems in education. The article includes brief opinion statements from teachers and other professionals. (SM)
White, Kerry A.
2000-01-01
In 1994, Long Beach (California) Unified School District began requiring uniforms in all elementary and middle schools. Now, half of all urban school systems and many suburban schools have uniform policies. Research on uniforms' effectiveness is mixed. Tightened dress codes may be just as effective and less litigious. (MLH)
Dowling-Sendor, Benjamin
2002-01-01
Reviews a recent decision in "Littlefield" by the 5th Circuit upholding a school uniform policy. Advises board member who wish to adopt a school uniform policy to solicit input from parents and students, research the experiences of other school districts with uniform policies, and articulate the interests they wish to promote through uniform…
Cohn, Carl A.
1996-01-01
Shortly after implementing a mandatory school uniform policy, the Long Beach (California) Public Schools can boast 99% compliance and a substantial reduction in school crime. The uniforms can't be confused with gang colors, save parents money, and help identify outsiders. A sidebar lists ingredients for a mandatory uniform policy. (MLH)
Transition wave in a supported heavy beam
Brun, Michele; Slepyan, Leonid I
2012-01-01
We consider a heavy, uniform, elastic beam rested on periodically distributed supports as a simplified model of a bridge. The supports are subjected to a partial destruction propagating as a failure wave along the beam. Three related models are examined and compared: (a) a uniform elastic beam on a distributed elastic foundation, (b) an elastic beam which mass is concentrated at a discrete set of points corresponding to the discrete set of the elastic supports and (c) a uniform elastic beam on a set of discrete elastic supports. Stiffness of the support is assumed to drop when the stress reaches a critical value. In the formulation, it is also assumed that, at the moment of the support damage, the value of the `added mass', which reflects the dynamic response of the support, is dropped too. Strong similarities in the behavior of the continuous and discrete-continuous models are detected. Three speed regimes, subsonic, intersonic and supersonic, where the failure wave is or is not accompanied by elastic waves ...
International Nuclear Information System (INIS)
A logic-based control software system, called Thaumaturgic Automated Control Logic (TACL), is under development at the Continuous Electron Beam Accelerator Facility in Newport News, VA. The first version of the software was placed in service in November, 1987 for control of cryogenics during the first superconducting RF cavity tests at CEBAF. In August, 1988 the control system was installed at the Cryogenic Test Facility (CTF) at CEBAF. CTF generated liquid helium in September, 1988 and is now in full operation for the current round of cavity tests. TACL is providing a powerful and flexible controls environment for the operation of CTF. 3 refs
School Uniform Policies in Public Schools
Brunsma, David L.
2006-01-01
The movement for school uniforms in public schools continues to grow despite the author's research indicating little if any impact on student behavior, achievement, and self-esteem. The author examines the distribution of uniform policies by region and demographics, the impact of these policies on perceptions of school climate and safety, and…
International Nuclear Information System (INIS)
The purpose of this study is to compare the quality of images obtained from the step-and-shoot and continuous scanning methods in terms of system resolution. In addition, this study aims to determine the fastest continuous scanning speed with image quality enough for the defect inspection. Computed tomography (CT) is an emerging technology for the non-destructive testing (NDT) of high precision manufacturing to enhance the production reliability. In order to use the CT for the NDT, high-speed inspection is essential for a higher production yield. However, conventional high resolution CT systems usually require terms of minutes to take exam because they employ the step-and-shoot protocol to avoid motion blur during the image acquisition. Unlike the step-and-shoot protocol, continuous scan protocol, which simultaneously acquires projection images during the rotation, can only require terms of seconds because it can ignore the time delay between 'stop and go' steps of rotation. Continuous scan is used for medical CT systems. However, the loss of system resolution originated from the motion blur cannot be avoidable. In order to investigate the relationship between acquisition time and image quality of continuous scanning, the experiment will be conducted with varying rotational speed of object
Directory of Open Access Journals (Sweden)
Leilei Zhang
2016-05-01
Full Text Available The flow transport of a 420 × 320 × 90 mm beam blank continuous casting mold that used open-stream pouring combined with submerged refractory funnels was studied. By considering the dynamic similarity, geometric similarity, and air entrapment quantity similarity, a full-size water model was established. Meanwhile, the 3D mathematical models that included three phases were applied. Through the combination of the water model and the mathematical model, the distribution and morphology of the phases in the mold were investigated. The results indicate that bubbles existed in the molten steel due to entrapment and the flow pattern was different from that of the full protection-poured mold. Furthermore, the effects of funnel immersion depth and funnel diameter on the bubbles’ impact depth, funnel’s inside wall shear stress, and overall area of the air/steel interface were discussed. The results provide useful information for the industrial continuous casting process.
Wiersma, R. D.; Riaz, N.; Dieterich, Sonja; Suh, Yelin; Xing, L.
2009-01-01
The integration of onboard kV imaging together with a MV electronic portal imaging device (EPID) on linear accelerators (LINAC) can provide an easy to implement real-time 3D organ position monitoring solution for treatment delivery. Currently, real-time MV-kV tracking has only been demonstrated by simultaneous imagining by both MV and kV imaging devices. However, modalities such as step-and-shoot IMRT (SS-IMRT), which inherently contain MV beam interruptions, can lead to loss of target information necessary for 3D localization. Additionally, continuous kV imaging throughout the treatment delivery can lead to high levels of imaging dose to the patient. This work demonstrates for the first time how full 3D target tracking can be maintained even in the presence of such beam interruption, or MV/kV beam interleave, by use of a relatively simple correlation model together with MV-kV tracking. A moving correlation model was constructed using both present and prior positions of the marker in the available MV or kV image to compute the position of the marker on the interrupted imager. A commercially available radiotherapy system, equipped with both MV and kV imaging devices, was used to deliver typical SS-IMRT lung treatment plans to a 4D phantom containing internally embedded metallic markers. To simulate actual lung tumor motion, previous recorded 4D lung patient motion data were used. Lung tumor motion data of five separate patients were inputted into the 4D phantom, and typical SS-IMRT lung plans were delivered to simulate actual clinical deliveries. Application of the correlation model to SS-IMRT lung treatment deliveries was found to be an effective solution for maintaining continuous 3D tracking during 'step' beam interruptions. For deliveries involving five or more gantry angles with 50 or more fields per plan, the positional errors were found to have <=1 mm root mean squared error (RMSE) in all three spatial directions. In addition to increasing the robustness of
A method to compensate the energy loss of a continuous stacked beam with a large momentum spread
International Nuclear Information System (INIS)
A system of rectangular drift tube loaded cavities resonating in the TE 101 mode combined with a cyclic scaling guide field can be used to accelerate an unbunched beam of charged particles. The system is superior to phase displacement because the cavities are driven at a fixed frequency with certain phase differences between each other. The range of particle momenta is limited by rf-knock out. Rf-induced betatron oscillations and phase dependent momentum changes can be compensated by means of sixteen cavities on the circumference of the accelerator. The amplitude of the betatron oscillations and the energy gain were calculated numerically for storage devices consisting of a spiral-sector FFAG guide field and one or sixteen cavities, respectively, using measured rf-feld data. The systems seem to be practical only for electrons with an energy up to 100 MeV. The rf-system works within an energy width of several MeV. (Auth.)
International Nuclear Information System (INIS)
In this environmental assessment (EA), the US Department of Energy (DOE) reports the results of an analysis of the potential environmental impacts from a proposed change in operating parameters of the Continuous Electron Beam Accelerator Facility (CEBAF), and operation of the Free Electron Laser (FEL) facility beyond the initial demonstration period. With this proposal, DOE intends to increase CEBAF operating range from its current operating maximum beam energy of 4.0 GeV [giga-(billion) electron volts] to 8.0 GeV at a beam power of no greater than 1,000 kW [1 megawatt (MW)], its maximum attainable level, based on current technology and knowledge, without significant, costly equipment modifications. DOE has prepared an EA for this action to determine the potential for adverse impacts from operation of CEBAF and the FEL at the proposed levels. Changing the operating parameters of CEBAF would require no new major construction and minor modifications to the accelerator, its support systems, the FEL, and onsite utility systems. Modifications and performance improvements would be made to (1) the accelerator housed in the underground tunnels, (2) its support systems located in the above ground service buildings, and (3) the water and equipment cooling systems both in the tunnel and at the ground surface. All work would be performed on previously disturbed land and in, on, or adjacent to existing buildings, structures, and equipment. With the proposed action, the recently constructed FEL facility at the Jefferson Lab would operate in concert with CEBAF beyond its demonstration period and up to its maximum effective electron beam power level of 210 kW. In this EA, DOE evaluates the impacts of the no-action alternative and the proposed action alternative. Alternatives considered, but dismissed from further evaluation, were the use of another accelerator facility and the use of another technology
How to Conduct Continuous Beam Construction by Hanging Basket Method%如何用挂篮法进行连续梁的施工
Institute of Scientific and Technical Information of China (English)
刘新华
2013-01-01
The prestressed reinforced concrete continuous beam bridge can give full play to the characteristics of high -strength materials and make the structure light, and it has great leap ability, and it can effectively avoid the cracking of concrete, especially bridge deck structure cracking in the negative moment area. This paper focuses on introducing the 0# segment cradle construction, pier beam provisional consolidation, hanging basket design, hanging basket installation, cantilever construction, system conversion, setting up temporary support, permanent support installation and other aspects of prestressed reinforced concrete continuous beam bridge construction by using hanging basket construction cantilever casting.% 预应力钢筋混凝土连续梁桥能充分发挥高强材料的特性，使结构轻型化，具有很大的跨越能力，而且它可以有效地避免混凝土的开裂，特别是处负弯矩区的桥面板的开裂。本文结合实践中的体会着重对预应力钢筋混凝土连续梁桥在采用挂篮施工悬臂浇筑时0#节段托架施工、墩梁临时固结、挂篮设计、挂篮安装、挂篮悬浇施工、体系转换、临时支座设置永久支座安装等方面进行了介绍。
School Uniforms. Research Brief
Walker, Karen
2007-01-01
Does clothing make the person or does the person make the clothing? How does what attire a student wears to school affect their academic achievement? In 1996, President Clinton cited examples of school violence and discipline issues that might have been avoided had the students been wearing uniforms ("School uniforms: Prevention or suppression?").…
Institute of Scientific and Technical Information of China (English)
Linda
2008-01-01
The uniforms for Beijing Olympics’ workers, technical staff and volunteers have been unveiled to mark the 200-day countdown to the Games. The uniforms feature the key element of the clouds of promise and will be in three colors:red for Beijing Olympic Games Committee staff, blue
Energy Technology Data Exchange (ETDEWEB)
Mori, Warren, B.
2012-12-01
We present results from the grant entitled, Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions. The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.
Yamano, Masayuki; Kuroki, Shin-Ichiro; Sato, Tadashi; Kotani, Koji
2014-01-01
Highly biaxially oriented poly-Si thin films were formed by double-line beam continuous-wave laser lateral crystallization (DLB-CLC). The crystallinities of the DLB-CLC poly-Si thin films were (110), (111), and (211) for the laser scan, transverse, and surface directions, respectively, and an energetically stable Σ3 grain boundary was observed to be dominant. All silicon grains were elongated in the laser scan direction and one-dimensionally very large silicon grains with lengths of more than 100 µm were fabricated. Using these biaxially oriented polycrystalline silicon (poly-Si) films, low-temperature poly-Si TFTs (LTPS-TFTs) were fabricated at low temperatures (≦550 °C) by a metal gate self-aligned process. As a result, a TFT with a high electron field effect mobility of μFE = 450 cm2 V-1 s-1 in a linear region was realized.
International Nuclear Information System (INIS)
After an introductory section on the relationship between emittance and beam Coulomb energy we discuss the properties of space charge dominated beams in progressive steps: from uniformly charged bunched beams to non-uniformly charged beams to correlation effects between particles (simulation beams or 'crystalline' beams). A practical application can be found in the beam dynamics of a high-current injector. The concept of correlation energy is of practical interest in computer simulation of high-brilliance beams, where one deals with an artificially enhanced two-particle Coulomb energy, if many real particles are combined into one simulation super-particle. This can be a source of non-physical emittance growth. (orig./HSI)
International Nuclear Information System (INIS)
Purpose: To evaluate the feasibility and efficacy of definitive continuous 7-days-a-week pelvic irradiation without breaks between external beam radiotherapy and brachytherapy in locally advanced cervical cancer. Methods and Materials: Between November 1998 and December 1999, 30 patients with International Federation of Obstetrics and Gynecology Stage IIB or IIIB cervical cancer were included in a prospective Phase I/II study of continuous 7-days-a-week pelvic irradiation, to the total Manchester point B dose of 40.0–57.6 Gy. The first 13 patients (Group A) were given a daily tumor dose of 1.6 Gy, and the remaining 17 patients (Group B) were given 1.8 Gy. One or two immediate brachytherapy applications (point A dose 10–20 Gy, each) were performed in 28 cases. Results: Two patients did not complete the irradiation because of apparent early progression of disease during the irradiation. Eleven of the 28 evaluable patients (39%; 45% and 35% in Groups A and B, respectively) completed their treatment within the prescribed overall treatment time. Acute toxicity (including severe European Organisation for Research and Treatment of Cancer/Radiation Therapy Oncology Group Grade 3 and 4 effects in 40%) was experienced by 83% of patients and resulted in unplanned treatment interruptions in 40% of all patients (31% and 47% of patients in Groups A and B, respectively). Severe intestinal side effects occurred in 31% and 41% of Patients in Groups A and B, respectively (p = 0.71). The 5-year overall survival probability was 33%. Cancer recurrence occurred in 63% of patients: 20% inside and 57% outside the pelvis. Cumulative incidence of late severe bowel and urinary bladder toxicity at 24 months was 15%. Conclusion: Continuous irradiation in locally advanced cervical cancer is associated with a high incidence of severe acute toxicity, resulting in unplanned treatment interruptions. Late severe effects and survival after continuous radiotherapy do not substantially differ from
Neutralization of low energy broad ion beam
International Nuclear Information System (INIS)
The paper is devoted to experimental and theoretical investigation of a low energy broad ion beam space charge and current compensation and ion-beam plasma (IBP), which would be created in transport space of the beam. The beam had cylindrical symmetry. The continuous uniform and hole tube like ion beams are used in the experiments. Different channels of electron appearing have been investigated for cases of neutralization due to secondary γ-electrons from the target and by electrons from glow cathode-neutralizer with metal or dielectric target. Results of neutralizing electrons energy distributions function measurements are presented as well as dependences of electron temperature and self-consisted plasma potential vs. beam parameters, ambient gas pressure, neutralizer parameters. Role of the thermoelectrons and dependence of IBP parameters on neutralizer area, location and potential are discussed. Significant role in neutralization of spatial collisional processes has been revealed even in neutralization by thermocathode. On the base of the experimental results self-consistent theoretical model have been developed, which describes the behavior of intense ion beam passing through the neutral gas at low pressure within conductive walls. The collisionless approach is used which means absence of collisional relaxation of the beam. This theory is used to derive the plasma potential and electron temperature within the beam
Uniform large-area thermionic cathode for SCALPEL
Katsap, Victor; Sewell, Peter B.; Waskiewicz, Warren K.; Zhu, Wei
1999-11-01
An electron beam lithography tool, which employs the SCALPEL technique, requires an extremely uniform beam to illuminate the scattering Mask, with the cathode operating in the temperature limited mode. It has been previously shown that LaB6 cathodes are not stable in this mode of operation. We have explored the possibility of implementing refined Tantalum-based emitters in the SCALPEL source cathode, and have developed large-area flat cathodes featuring suitably high emission uniformity under temperature limited operation.
International Nuclear Information System (INIS)
Purpose: The purpose of this study was to evaluate whether external-beam radiotherapy (EBRT) with concurrent continuous 5-fluorouracil (5-FU) infusion affects the length and quality of survival in patients with locally unresectable pancreatic cancer. Methods: Thirty-one patients with histologically proven locally advanced and unresectable pancreatic cancer without distant metastases were evaluated in this prospective randomized trial. Sixteen patients received EBRT (50.4 Gy/28 fractions) with concurrent continuous infusion of 5-FU (200 mg/m2/day), whereas 15 patients received no chemoradiation. The length and quality of survival was analyzed and compared for the two groups. Results: The median survival of 13.2 months and the 1-year survival rate of 53.3% in the chemoradiation group were significantly better than the respective 6.4 months and 0% in the group without chemoradiotherapy (p=0.0009). The average monthly Karnofsky score, a quality of life indicator, was 77.1 in the chemoradiation group, which was significantly higher than the 65.5 in the group without chemoradiotherapy (p<0.0001). The number of hospital days per month of survival was significantly less in the chemoradiation than in the no-therapy group (12.3 vs. 19.0 days, p<0.05). In the chemoradiation group, 5 patients (31%) had a partial response, and 9 (56%) had radiologically stable disease at a median duration of 6.1 months. The patients who had chemoradiation had a lower rate of liver and peritoneal metastases than patients without chemoradiotherapy (31% vs. 64%). Of 10 patients who experienced pain before chemoradiation, 8 (80%) received pain relief that lasted a median of 5.2 months. Conclusions: EBRT with concurrent continuous 5-FU infusion increased the length and quality of survival as compared to no chemoradiotherapy and provided a definite palliative benefit for patients with unresectable pancreatic cancer
International Nuclear Information System (INIS)
Highlights: • A graphene/silicon multilayer is fabricated by electron beam deposition. • It exhibits specific capacity retention over 1000 mA h g−1. • Capacity retention at 100 nm and 7-layer exceeds 90%. • It can be used for lighting of light-emitting diodes. - Abstract: A graphene/silicon (Si) multilayer sandwich structures are fabricated using electron beam (EB) deposition without air exposure. The graphene and Si thin films are formed on Cu current correctors through a continuous process in high-vacuum EB chamber. Synthesized graphene should be suggested to the stacked multiple layer from Raman analysis. The fabricated multilayer films are used as anodes. In the beginning, the half-cell, which used a seven-layer of each thickness 50-nm graphene and Si film, exhibits good specific capacity retention over 1000 mA h g−1 after 30 charge/discharge cycles. The capacity value changed with the number of graphene and Si layers. In this study, the number of layers that exhibited optimal properties is seven. Morphological investigation showed a fine layer-by-layer structure. The relationship between different thicknesses of graphene and Si is investigated at 7 L. A 100-nm thickness exhibited optimal properties. Finally, the optimal 7 L and 100-nm thick graphene/Si exhibited high discharge capacitance >1600 mA h g−1 at a current density of 100 mA g−1 after 30 cycles. Initial coulombic and reversible efficiencies exceed 84%. The capacity retention (30th/1st discharge value) at 100 nm and 7 L exceeds 90%. Finally, the soft package battery is assembled by combining the fabricated graphene and Si electrode as anode, LiCoO2 as cathode, separator and liquid electrolyte. It can be used for commercial light-emitting diode (LED) lighting even under bending status
Beam halo in high-intensity beams
International Nuclear Information System (INIS)
In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam
International Nuclear Information System (INIS)
Purpose: To determine the feasibility of combining external beam radiotherapy, continuous infusion 5-fluorouracil (5-FU), and external microwave hyperthermia in patients with locally advanced, unresectable, or recurrent adenocarcinoma of the rectum. Methods and Materials: From 7/95 through 2/99, 15 patients were enrolled in the study. The treatment regimen consisted of continuous infusion 5-FU 250 mg/m2/d 7 days/week beginning on day 1, external beam radiotherapy to the pelvis, 4500 cGy, 180 cGy/d 5 days/week using a 3 or 4-field technique, and external microwave hyperthermia on days 3, 8, 15, 22, and 29. Chemotherapy was stopped on the last day of radiotherapy. Surgical resection, if feasible, was scheduled 3-6 weeks after completing thermochemoradiotherapy. For this regimen to be considered feasible, no more than 2 of the 15 patients should fail to complete therapy due to life-threatening toxicity. Toxicity was scored using National Cancer Institute Criteria. Results: All patients completed the chemoradiotherapy portion of the protocol. Eleven of the 15 patients completed all 5 hyperthermia treatments. Of the 4 patients who did not receive the full course of hyperthermia, only 1 patient had treatment stopped due to life-threatening toxicity. The other 3 patients did not complete hyperthermia due to scheduling errors (n = 2) or patient request (n = 1). Five of 15 patients required a treatment interruption due to toxicity no. >=no. Grade 3. Seven patients experienced lesser degrees of toxicity which did not require treatment interruption. Three patients experienced no side effects. The most common toxicities were dermatitis and diarrhea. Of the 14 patients in whom surgery was planned, 11 (79%) were resectable. There was one pathologic complete response. Conclusions: It is feasible to deliver thermochemoradiotherapy, as prescribed in this study, to patients with locally advanced, unresectable, or recurrent rectal cancer. The therapy is moderately toxic, with one
Herr, W
2014-01-01
One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.
Institute of Scientific and Technical Information of China (English)
贾远林; 陈世鸣; 王新娣
2012-01-01
Unlike simply supported beams under positive moment, the ultimate load carrying capacity of continuous steel-concrete composite beams is usually limited by either the local buckling failure of steel section or the distortional lateral buckling near interior supports, which is because the sleel plate under the negative moment near interior is subjected to compression and inclined to instability. However, the simplified plastic theory taking no account of the instability of the beam will lead to a unconservative result. Four full-scale continuous composite beams were tested, among which two were two-span beams with class 2 cross-section and two were three-span beams with class 3 cross-section. One of the two-span beams was a conventional non-pres-tressed composite beam, and the other was a composite beam preslressed with external tendons in both the positive and negative moment regions. One of the three-span composite beams was non- prestressed, and the other was prestressed only in the negative moment regions with external high-strength tendons. The experimental results indicates that all beams collapsed with the characteristic of concrete crushing in sagging moment, and the web local buckling and distortional buckling of the steel beam. The capacity of beams in positive moment can be calculated by simplified plastic theory, while the capacity of beams in negative moment is affected by section classification divided hy width to thickness ratio of the plate,the simplified calculation method based on the web buckling is agreed well with the experimental results. A numerical analysis was conducted for all the beams considering interface slipping, prestressing force, and so on, which agrees well with the experimental results.Unlike simply supported beams under positive moment, the ultimate load carrying capacity of continuous steel-concrete composite beams is usually limited by either the local buckling failure of steel section or the distortional lateral buckling near
Institute of Scientific and Technical Information of China (English)
贾远林; 陈世鸣; 王新娣
2012-01-01
Unlike simply supported beams under positive moment, the ultimate load carrying capacity of continuous steel-concrete composite beams is usually limited by either the local buckling failure of steel section or the distortional lateral buckling near interior supports, which is because the sleel plate under the negative moment near interior is subjected to compression and inclined to instability. However, the simplified plastic theory taking no account of the instability of the beam will lead to a unconservative result. Four full-scale continuous composite beams were tested, among which two were two-span beams with class 2 cross-section and two were three-span beams with class 3 cross-section. One of the two-span beams was a conventional non-pres-tressed composite beam, and the other was a composite beam preslressed with external tendons in both the positive and negative moment regions. One of the three-span composite beams was non- prestressed, and the other was prestressed only in the negative moment regions with external high-strength tendons. The experimental results indicates that all beams collapsed with the characteristic of concrete crushing in sagging moment, and the web local buckling and distortional buckling of the steel beam. The capacity of beams in positive moment can be calculated by simplified plastic theory, while the capacity of beams in negative moment is affected by section classification divided hy width to thickness ratio of the plate,the simplified calculation method based on the web buckling is agreed well with the experimental results. A numerical analysis was conducted for all the beams considering interface slipping, prestressing force, and so on, which agrees well with the experimental results.Unlike simply supported beams under positive moment, the ultimate load carrying capacity of continuous steel-concrete composite beams is usually limited by either the local buckling failure of steel section or the distortional lateral buckling near
Effect of Scanning Beam Profile to Fabricate Fused Fiber Tapers by CO_2 Laser Irradiation Method
Institute of Scientific and Technical Information of China (English)
Bayle; Fabien; Luo; Aiping; Marin; Emmanuel; Meunier; Jean-Pierre
2003-01-01
Beam uniformity is a crucial building block of CO2 experiments aimed at fusing and stretching optical fibers in a lossless manner. When the irradiation beam is expanded through a galvanometer mirror, ways to achieve beam uniformity are investigated.
Effect of Scanning Beam Profile to Fabricate Fused Fiber Tapers by CO2 Laser Irradiation Method
Institute of Scientific and Technical Information of China (English)
Bayle Fabien; Luo Aiping; Marin Emmanuel; Meunier Jean-Pierre
2003-01-01
Beam uniformity is a crucial building block of CO2 experiments aimed at fusing and stretching optical fibers in a lossless manner. When the irradiation beam is expanded through a galvanometer mirror, ways to achieve beam uniformity are investigated.
H. Buhrman; B. Hescott; S. Homer; L. Torenvliet
2010-01-01
We study properties of non-uniform reductions and related completeness notions. We strengthen several results of Hitchcock and Pavan (ICALP (1), Lecture Notes in Computer Science, vol. 4051, pp. 465-476, Springer, 2006) and give a trade-off between the amount of advice needed for a reduction and its
半连轧工字钢工艺设计与改进%Design and Improvement on I-beam Steel Semi-continuous Rolling Process
Institute of Scientific and Technical Information of China (English)
孔利明
2015-01-01
文章介绍了新建半连轧工字钢万能轧机生产线的工艺布置、设备性能参数，重点介绍了在部分设备利旧条件下，轧制极限规格产品在孔型设计上存在的实际问题及改进后的效果。结合生产实践探讨了轧件在粗轧道次、万能孔型中的变形规律、控制要点。介绍了针对影响轧制稳定性所采取的一些改进措施。%This paper introduces the new semi- continuous I-beam universal section rolling production line in terms of process layout and equipment performance parameters. It focuses on the practical issues in the interest of the old part of the equipment condition about rolling pass design product specification limits on the presence and the effects after im-provement. Combined with practical applications, the rolling in the roughing passes, the deformation and controlling es-sentials of the universal pass are discussed. Some improved measures that affect the stability of rolling are adopted.
Energy Technology Data Exchange (ETDEWEB)
Guimaraes, Margarete Cristina
2014-07-01
Personal radiation monitoring is a basic procedure to verify the compliance to regulatory requirements for radiological protection. Electronic personal dosimeters (EPD) based on solid state detectors have largely been used for personnel monitoring; including for pulsed radiation beams where their responses are not well known and deficiencies have been reported. In this work, irradiation conditions for testing the response of EPDs in both continuous and pulsed X-ray beams were studied to be established in a constant potential Seifert-Pantak and in a medical Pulsar 800 Plus VMI X-ray machines. Characterization of X-ray beams was done in terms of tube voltage, half-value layer, mean energy and air kerma rate. A Xi R/F Unfors solid state dosimeter used as reference for air kerma measurements was verified against a RC-6 and 10X6-6 Radical ionization chambers as far its metrological coherence. Rad-60 RADOS, PDM- 11 Aloka and EPD MK2 Thermo electron EPDs were selected to be tested in terms of relative intrinsic error and energy response in similar to IEC RQR, IEC RQA and ISO N reference radiations. Results demonstrated the reliability of the solid state Xi R/F Unfors dosimeter to be as reference dosimeter although its response was affected by heavily filtered beams. Results also showed that relative intrinsic errors in the response of the EPDs in terms of personal dose equivalent, Hp(10), were higher than the requirement established for continuous beams. In pulsed beams, some EPDs showed inadequate response and high relative intrinsic errors. This work stressed the need of performing additional checks for EPDs, besides the limited {sup 137}Cs beam calibration, before using them in pulsed X-ray beams. (author)
Pemantle, Robin
2004-01-01
There are several good reasons you might want to read about uniform spanning trees, one being that spanning trees are useful combinatorial objects. Not only are they fundamental in algebraic graph theory and combinatorial geometry, but they predate both of these subjects, having been used by Kirchoff in the study of resistor networks. This article addresses the question about spanning trees most natural to anyone in probability theory, namely what does a typical spanning tree look like?
Hanna Karaszewska; Maciej Muskała
2012-01-01
The article discusses the problems of women who work in the uniformed services with the particular emphasis on the performing of the occupation of the prison service. It presents the legal issues relating to equal treatment of men and women in the workplace, formal factors influencing their employment, the status of women in prison, and the problems of their conducting in the professional role. The article also presents the results of research conducted in Poland and all over the world, on th...
Uniform Requirements for Manuscripts
Institute of Scientific and Technical Information of China (English)
2011-01-01
@@ Introduction The Uniform requirements are instructions to authors on how to prepare manuscripts.If authors prepare their manuscripts in the style specified in these requirements, editors of the participating journals will not return the manuscripts for changes in style before considering them for publication.In the publishing process, however, the journals may alter accepted manuscripts to conform with details of their publication styles.
磷石膏空腔模无梁楼盖的连续化分析%A Continuous Analysis on Phosphorus Gypsum Evacuated Mould Floor without Beam
Institute of Scientific and Technical Information of China (English)
谢钦; 黄勇; 王佳炜; 贾航
2012-01-01
通过运用ansys软件对磷石膏空腔模无梁楼盖进行截面应力分析，提出了该类方盒空心板连续化模型的基本假定。将空心板分别分为不考虑表层抗弯刚度与考虑表层抗弯刚度两种情况建立分析模型，采用连续化分析方法，推导了2种情况下空心板的基本方程，进而建立了周边简支条件下各自的内力和位移计算公式。用精细有限元方法，对实例进行了数值模拟，所得有限元计算值与连续化分析所得结果吻合较好，2种情况的最大相对误差分别为8．38％和7．78％，考虑表层抗弯刚度时的精确度较高，表明所提方法的正确、合理性。文中所提方法和公式均通过理论、数值验证，可作为磷石膏空腔模无梁楼差研究的理论基础。%The software of ANSYS was applied to study the cross section stress of phosphorus gypsum evacuated mould floor without beam. A basic assumption of square hollow slab continuous model was put forward in this pa- per. Two analysis models were established for the hollow slabs in two situations-the flexural stiffness of surface layer not considered and the flexural stiffness of surface layer considered. The basic equation was given for these two ca- ses by adopting the method of continuous analysis to set up calculation formula of the internal force and displace- ment with the surrounding and simply supported condition. Finite element method was taken to do numerical simu- lation on some examples. The results showed that the finite element calculation was in good agreement with the con- tinuous analysis method. The maximum relative errors of the two cases were 8.38 % and 7.78 % respectively. The flexural stiffness of surface layer considered had a higher accuracy, which suggested that the proposed method was correct and rational. The method and formula were proved by theory and numerical simulation and could be used as a theory basis for phosphate gypsum evacuated
Institute of Scientific and Technical Information of China (English)
姚文娟; 叶志明
2011-01-01
Materials with different modulus in tension and compression have a wide application in engineering practice, especially the composite materials developed in recent years, which have properties of different tension-compression modulus. The determinant theorem of neutral axis for continuous beam with different modulusunder complex stress was suggests,and the formulae of neutral axis as well as the analytical solution of stress for structures with different modulus by segmental integral method were deduced.Some examples were calculated by the different modulus and the single modulus in classic mechanics, respectively, and stress difference of two methods was elicited. In the end, the reasonable suggestion on calculation of this type of structure, and the method of structure optimization by using different modulus were proposed.%拉压不同模量的材料在工程中应用很广,特别是近几年发展起来的复合材料都具有明显的拉压不同模量性质.本文对复杂应力状态下不同模量连续梁提出了中性轴判断定理,并用分段积分方法推导出不同模量结构的中性层计算表达式及应力的解析解.通过对实例的计算及分析,得出不同模量与经典力相同模量两种方法在结构应力计算上的差异,最后提出对该类结构计算的合理建议以及利用不同模量优化结构的方法.
Uniform distribution of sequences
Kuipers, L
2006-01-01
The theory of uniform distribution began with Hermann Weyl's celebrated paper of 1916. In later decades, the theory moved beyond its roots in diophantine approximations to provide common ground for topics as diverse as number theory, probability theory, functional analysis, and topological algebra. This book summarizes the theory's development from its beginnings to the mid-1970s, with comprehensive coverage of both methods and their underlying principles.A practical introduction for students of number theory and analysis as well as a reference for researchers in the field, this book covers un
Energy Technology Data Exchange (ETDEWEB)
Giovannini, Massimo, E-mail: massimo.giovannini@cern.ch [Department of Physics, Theory Division, CERN, 1211 Geneva 23 (Switzerland); INFN, Section of Milan-Bicocca, 20126 Milan (Italy)
2015-06-30
Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.
Directory of Open Access Journals (Sweden)
Hanna Karaszewska
2012-12-01
Full Text Available The article discusses the problems of women who work in the uniformed services with the particular emphasis on the performing of the occupation of the prison service. It presents the legal issues relating to equal treatment of men and women in the workplace, formal factors influencing their employment, the status of women in prison, and the problems of their conducting in the professional role. The article also presents the results of research conducted in Poland and all over the world, on the functioning of women in prison and their relations with officers of the Prison Service, as well as with inmates.
Energy Technology Data Exchange (ETDEWEB)
Amore, Paolo; Saenz, Ricardo A; Salvo, Koen [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal DIaz del Castillo 340 Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (UNLP, CCT La Plata-Conicet), Diag. 113 y 64 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)], E-mail: paolo.amore@gmail.com, E-mail: fernande@quimica.unlp.edu.ar, E-mail: rasaenz@ucol.mx, E-mail: koen.salvo@gmail.com
2009-03-20
In this paper we derive four sets of sinc-like functions, defined on a finite interval and obeying different boundary conditions. The functions in each set are orthogonal and their nodes are uniformly distributed on the interval. We have applied each set to solve a large class of eigenvalue equations, with different boundary conditions, both on finite intervals and on the real line, showing that precise numerical results can be obtained efficiently and rapidly. A comparison with results available in the literature is also performed.
Uniformly rotating neutron stars
Boshkayev, Kuantay
2016-01-01
In this chapter we review the recent results on the equilibrium configurations of static and uniformly rotating neutron stars within the Hartle formalism. We start from the Einstein-Maxwell-Thomas-Fermi equations formulated and extended by Belvedere et al. (2012, 2014). We demonstrate how to conduct numerical integration of these equations for different central densities ${\\it \\rho}_c$ and angular velocities $\\Omega$ and compute the static $M^{stat}$ and rotating $M^{rot}$ masses, polar $R_p$ and equatorial $R_{\\rm eq}$ radii, eccentricity $\\epsilon$, moment of inertia $I$, angular momentum $J$, as well as the quadrupole moment $Q$ of the rotating configurations. In order to fulfill the stability criteria of rotating neutron stars we take into considerations the Keplerian mass-shedding limit and the axisymmetric secular instability. Furthermore, we construct the novel mass-radius relations, calculate the maximum mass and minimum rotation periods (maximum frequencies) of neutron stars. Eventually, we compare a...
Uniform quantized electron gas.
Høye, Johan S; Lomba, Enrique
2016-10-19
In this work we study the correlation energy of the quantized electron gas of uniform density at temperature T = 0. To do so we utilize methods from classical statistical mechanics. The basis for this is the Feynman path integral for the partition function of quantized systems. With this representation the quantum mechanical problem can be interpreted as, and is equivalent to, a classical polymer problem in four dimensions where the fourth dimension is imaginary time. Thus methods, results, and properties obtained in the statistical mechanics of classical fluids can be utilized. From this viewpoint we recover the well known RPA (random phase approximation). Then to improve it we modify the RPA by requiring the corresponding correlation function to be such that electrons with equal spins can not be on the same position. Numerical evaluations are compared with well known results of a standard parameterization of Monte Carlo correlation energies. PMID:27546166
Uniform quantized electron gas
Høye, Johan S.; Lomba, Enrique
2016-10-01
In this work we study the correlation energy of the quantized electron gas of uniform density at temperature T = 0. To do so we utilize methods from classical statistical mechanics. The basis for this is the Feynman path integral for the partition function of quantized systems. With this representation the quantum mechanical problem can be interpreted as, and is equivalent to, a classical polymer problem in four dimensions where the fourth dimension is imaginary time. Thus methods, results, and properties obtained in the statistical mechanics of classical fluids can be utilized. From this viewpoint we recover the well known RPA (random phase approximation). Then to improve it we modify the RPA by requiring the corresponding correlation function to be such that electrons with equal spins can not be on the same position. Numerical evaluations are compared with well known results of a standard parameterization of Monte Carlo correlation energies.
Should School Nurses Wear Uniforms?
Journal of School Health, 2001
2001-01-01
This 1958 paper questions whether school nurses should wear uniforms (specifically, white uniforms). It concludes that white uniforms are often associated with the treatment of ill people, and since many people have a fear reaction to them, they are not necessary and are even undesirable. Since school nurses are school staff members, they should…
Institute of Scientific and Technical Information of China (English)
张直明
2013-01-01
This paper discusses the mass construction of prestressed concrete continuous beam support engineering application advantages, specific discussed coal mass body building prestressed continuous beam support engineering design and construction steps, finally to a coal mass body building is simulated and construction security analysis.%文章首先论述了大体积建筑体预应力混凝土连续梁支架工程的应用优点，具体探讨了煤炭大体积建筑体的预应力连续梁支架工程设计与施工步骤，最后对某煤炭大体积建筑体进行了仿真与施工保障分析。
Skin carcinogenesis following uniform and non-uniform β irradiation
International Nuclear Information System (INIS)
Where workers or the general public may be exposed to ionising radiation, the irradiation is rarely uniform. The risk figures and dose limits recommended by the International Commission on Radiological Protection (ICRP) are based largely on clinical and epidemiological studies of reasonably uniform irradiated organs. The paucity of clinical or experimental data for highly non-uniform exposures has prevented the ICRP from providing adequate recommendations. This weakness has led on a number of occasions to the postulate that highly non-uniform exposures of organs could be 100,000 times more carcinogenic than ICRP risk figures would predict. This so-called ''hot-particle hypothesis'' found little support among reputable radiobiologists, but could not be clearly and definitively refuted on the basis of experiment. An experiment, based on skin tumour induction in mouse skin, is described which was developed to test the hypothesis. The skin of 1200 SAS/4 male mice has been exposed to a range of uniform and non-uniform sources of the β emitter 170Tm (Emax ∼ 1 MeV). Non-uniform exposures were produced using arrays of 32 or 8 2-mm diameter sources distributed over the same 8-cm2 area as a uniform control source. Average skin doses varied from 2-100 Gy. The results for the non-uniform sources show a 30% reduction in tumour incidence by the 32-point array at the lower mean doses compared with the response from uniform sources. The eight-point array showed an order-of-magnitude reduction in tumour incidence compared to uniform irradiation at low doses. These results, in direct contradiction to the ''hot particle hypothesis'', indicate that non-uniform exposures produce significantly fewer tumours than uniform exposures. (author)
Extensional Uniformity for Boolean Circuits
McKenzie, Pierre; Vollmer, Heribert
2008-01-01
Imposing an extensional uniformity condition on a non-uniform circuit complexity class C means simply intersecting C with a uniform class L. By contrast, the usual intensional uniformity conditions require that a resource-bounded machine be able to exhibit the circuits in the circuit family defining C. We say that (C,L) has the "Uniformity Duality Property" if the extensionally uniform class C \\cap L can be captured intensionally by means of adding so-called "L-numerical predicates" to the first-order descriptive complexity apparatus describing the connection language of the circuit family defining C. This paper exhibits positive instances and negative instances of the Uniformity Duality Property.
Study of beam transport lines for a biomedical research facility at CERN based on LEIR
Abler, D; Garonna, A; Peach, K
2014-01-01
The Low Energy Ion Ring (LEIR) at CERN has been proposed to provide ion beams with magnetic rigidities up to 6.7 T.m for biomedical research, in parallel to its continued operation for LHC and SPS fixed target physics experiments. In the context of this project, two beamlines are proposed for transporting the extracted beam to future experimental end-stations: a vertical beamline for specific low-energy radiobiological research, and a horizontal beamline for radiobiology and medical physics experimentation. This study presents a first linear-optics design for the delivery of 1–5mm FWHM pencil beams and 5 cm 5 cm homogeneous broad beams to both endstations. High field uniformity is achieved by selection of the central part of a strongly defocused Gaussian beam, resulting in low beam utilisation.
Institute of Scientific and Technical Information of China (English)
程东辉; 王天峰; 易亚敏
2011-01-01
为了开展碳纤维布加固钢筋混凝土连续梁受力性能的研究工作,对3根两跨采用碳纤维布加固的钢筋混凝土连续梁进行三分点加载的受力性能试验研究,获得加固状态下钢筋混凝土连续梁正截面承载力、裂缝分布及开展、中支座塑性铰区分布长度等试验实测值和荷载-挠度曲线及内力重分布关系曲线。试验研究表明：钢筋混凝土连续梁在加固状态下的破坏呈现中支座纵向受力钢筋先屈服,跨中纵向受力钢筋后屈服,碳纤维布被拉断的形式;试验梁加载过程中有明显的内力重分布,承载力极限状态下内力重分布幅度超过50%;由于跨中碳纤维布的存在约束了连续梁的变形,从而导致中支座控制截面附近塑性区域分布长度比普通钢筋混凝土连续梁有所减小。%In order to study the mechanical behavior of concrete continuous beams strengthened with CFRP sheets, 3 two-span continuous beams were fabricated, and strengthened with CFRP sheets at each span. The test of loading on two-point was completed, from which the bearing capacity, cracks distribution, the test value of the length of plastic hinge region, curves of load-deformation and curves of internal force redistribution were obtained. The test results showed that the failure of concrete continuous beams strengthened with CFRP sheets was characterized by longtitudinal reinforcement yielded in intermediate support sections, then the longtitudinal reinforcement yielded in the middle span sections, at last carbon fiber polymer sheets were pulled off. The internal force redistribution appeared apparently in beams during loading process and the redistribution rate was over 50% in the state of ultimate bearing capacity. As CFRP confined the deflection of beams,the length of the plastic hinge region near the sections of intermediate support was reduced as compared to ordinary continuous reinforced beams.
Reflective optics system for uniform spherical illumination.
Phipps, C R; Bodner, S E; Shearer, J W
1975-04-01
A reflective optical system is described that permits nearly uniform illumination of a small sphere with one or two laser beams. The primary application of this device is to studies of laser-driven implosion of small targets. Other applications include the production of plasma by optical breakdown of gases for spectroscopic studies and for optimum light collection in intensity-limited plasma diagnostics. Simple calculations show that the intensity mapping properties of this system are not excessively sensitive to variations in the radial intensity distribution nor to departures from diffraction-limited propagation in the input beams. Optical damage and the illuminated solid angle required at the focus determine the size of the device. PMID:20135009
A device used in pulsed slow positron beam's stretching
International Nuclear Information System (INIS)
A slow positron beam's stretching device has been designed and constructed on Beijing Slow Positron Beam, which based on a 1.3 GeV linac. Positron was storage and stretching use Penning-Trap technique. Measurements show that the positron storage time strongly depends on the vacuum level in Penning Trap tube. Two modes was used to release the positrons from storage part, lowering VC while VB kept constant and rising VB while VC kept constant. This technique makes the pulsed positron beam to a quasi-continuous beam. The energy spread of positrons depend on in release mode. In the latter mode, the authors observe that the energy spread was reduced to a value less than 1.0 eV. The time profile in user-defined waveform is more uniform. It is beneficial to reduce the probability of amplifier pileup especially in the case of measurement with high counting rate. (authors)
Directory of Open Access Journals (Sweden)
D.C. Robertson
2012-02-01
Full Text Available 1979 saw the celebration of the 150th anniversary of the founding of an educational establishment in the Cape which was to develop into the University of Cape Town. To mark this anniversary the authors have presented a short history of UCT in uniform, highlighting the multifarious contributions made by UCTstudents and staff. This documented history clearly indicates the valuable contribution that not only UCT but all South African universities and their members have made in the past and will be called to make in the future. Changes in national service policy particularly with regard to urban commandos have resulted in the replacement of the UCT Regiment by the Cape Garrison Artillery. However, the loss of the UCT Regiment itself, certainly does not point to the end of UCT's contribution to the defence of South Africa. For at this very moment, in diverse regiments throughout South Africa, members of the UCT community are making a valiant contribution in answering the call of their country.
Janicic, Predrag
2010-01-01
There is a huge number of problems, from various areas, being solved by reducing them to SAT. However, for most applications, translations into SAT are performed by specialized, problem-specific tools. In this paper we describe a novel approach for uniform solving of a wide class of problems by reducing them to SAT. The approach uses a new specification language that combines imperative and declarative programming paradigms. A problem is specified by a test (expressed in an imperative form) that a given set of values indeed makes a solution to the problem. In the solving phase, parameters of the problem are represented by (finite) vectors of propositional formulae and the specification is symbolically executed. An assertion that given values make a solution is transformed to an instance of the SAT problem and passed to a SAT solver. If the formula is satisfiable, its model is transformed back to variables describing the problem, i.e., to a solution of the problem. We also describe a system URSA that implement...
Assessment indices for uniform and non-uniform thermal environments
Institute of Scientific and Technical Information of China (English)
2008-01-01
Different assessment indices for thermal environments were compared and selected for proper assessment of indoor thermal environments.30 subjects reported their overall thermal sensation,thermal comfort,and thermal acceptability in uniform and non-uniform conditions.The results show that these three assessment indices provide equivalent evaluations in uniform environments.However,overall thermal sensation differs from the other two indices and cannot be used as a proper index for the evaluation of non-uniform environments.The relationship between the percentage and the mean vote for each index is established.
Energy Technology Data Exchange (ETDEWEB)
Zholents, A.
1994-12-01
The term beam-beam effects is usually used to designate different phenomena associated with interactions of counter-rotating beams in storage rings. Typically, the authors speak about beam-beam effects when such interactions lead to an increase of the beam core size or to a reduction of the beam lifetime or to a growth of particle`s population in the beam halo and a correspondent increase of the background. Although observations of beam-beam effects are very similar in most storage rings, it is very likely that every particular case is largely unique and machine-dependent. This constitutes one of the problems in studying the beam-beam effects, because the experimental results are often obtained without characterizing a machine at the time of the experiment. Such machine parameters as a dynamic aperture, tune dependencies on amplitude of particle oscillations and energy, betatron phase advance between the interaction points and some others are not well known, thus making later analysis uncertain. The authors begin their discussion with demonstrations that beam-beam effects are closely related to non linear resonances. Then, they will show that a non linearity of the space charge field is responsible for the excitation of these resonances. After that, they will consider how beam-beam effects could be intensified by machine imperfections. Then, they will discuss a leading mechanism for the formation of the beam halo and will describe a new technique for beam tails and lifetime simulations. They will finish with a brief discussion of the coherent beam-beam effects.
Non-uniform Euler-Bernoulli beams’ natural frequencies
Directory of Open Access Journals (Sweden)
Hugo Aya
2011-05-01
Full Text Available This paper has studied the problem of natural frequencies for Euler-Bernoulli beams having non-uniform cross-section. The numerically-obtained solutions were compared to asymptotic solutions obtained by the Wentzel-Kramers-Brillouin (WKB method. It was established that WKB formula precision was higher than 3% for high frequencies (≥ 4 mode.
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Relation of optical properties in a uniform fiber Bragg grating(FBG) with its grating parameters and the laser beam engraving conditions is analyzed. The principle and method for designing the uniform FBG used in dense wavelength division multiplexing(DWDM) system is given. By adopting the double exposure technique, with a uniform phase mask and Gaussian laser beam, the uniform FBG used in DWDM system is designed and engraved, whose bandwidth of the main reflection band is about 0.4nm and 0.7nm at -5dB and -25dB respectively.
Graphene Conductance Uniformity Mapping
DEFF Research Database (Denmark)
Buron, Jonas Christian Due; Petersen, Dirch Hjorth; Bøggild, Peter;
2012-01-01
We demonstrate a combination of micro four-point probe (M4PP) and non-contact terahertz time-domain spectroscopy (THz-TDS) measurements for centimeter scale quantitative mapping of the sheet conductance of large area chemical vapor deposited graphene films. Dual configuration M4PP measurements......, demonstrated on graphene for the first time, provide valuable statistical insight into the influence of microscale defects on the conductance, while THz-TDS has potential as a fast, non-contact metrology method for mapping of the spatially averaged nanoscopic conductance on wafer-scale graphene with scan times...... of less than a minute for a 4-in. wafer. The combination of M4PP and THz-TDS conductance measurements, supported by micro Raman spectroscopy and optical imaging, reveals that the film is electrically continuous on the nanoscopic scale with microscopic defects likely originating from the transfer process...
Uniformity of fuel target implosion in Heavy Ion Fusion
Kawata, S; Suzuki, T; Karino, T; Barada, D; Ogoyski, A I; Ma, Y Y
2015-01-01
In inertial confinement fusion the target implosion non-uniformity is introduced by a driver beams' illumination non-uniformity, a fuel target alignment error in a fusion reactor, the target fabrication defect, et al. For a steady operation of a fusion power plant the target implosion should be robust against the implosion non-uniformities. In this paper the requirement for the implosion uniformity is first discussed. The implosion uniformity should be less than a few percent. A study on the fuel hotspot dynamics is also presented and shows that the stagnating plasma fluid provides a significant enhancement of vorticity at the final stage of the fuel stagnation. Then non-uniformity mitigation mechanisms of the heavy ion beam (HIB) illumination are also briefly discussed in heavy ion inertial fusion (HIF). A density valley appears in the energy absorber, and the large-scale density valley also works as a radiation energy confinement layer, which contributes to a radiation energy smoothing. In HIF a wobbling he...
Continuous leaky-wave scanning using periodically modulated spoof plasmonic waveguide.
Kong, Gu Sheng; Ma, Hui Feng; Cai, Ben Geng; Cui, Tie Jun
2016-07-12
The plasmonic waveguide made of uniform corrugated metallic strip can support and guide spoof surface plasmon polaritons (SSPPs) with high confinements. Here, we propose periodically-modulated plasmonic waveguide composed of non-uniform corrugated metallic strip to convert SSPPs to radiating waves, in which the main beam of radiations can steer continuously as the frequency changes. To increase the radiation efficiency of the periodically-modulated plasmonic waveguide at the broadside, an asymmetrical plasmonic waveguide is further presented to reduce the reflections and realize continuous leaky-wave scanning. Both numerical simulations and experimental results show that the radiation efficiency can be improved greatly and the main beam of leaky-wave radiations can steer from the backward quadrant to the forward quadrant, passing through the broadside direction, which generally is difficult to be realized by the common leaky-wave antennas.
School Uniforms: Esprit de Corps.
Ryan, Rosemary P.; Ryan, Thomas E.
1998-01-01
The benefits of school uniforms far outweigh their short-term costs. School uniforms not only keep students safe, but they increase their self-esteem, promote a more positive attitude toward school, lead to improved student behavior, and help blur social-class distinctions. Students are allowed to wear their own political or religious messages,…
Institute of Scientific and Technical Information of China (English)
胡少伟; 龚洪波
2013-01-01
The static load of four prestressed steel concrete continuous composite beams was tested in order to research the effects of the degree of shear connection on the bending behaviors of prestressed steel concrete continuous composite beams, such as the load-deflection characteristic, the load-slip along the span of beams, the strain distribution along the height of composite section, the load-stress increment of prestressed tendons, the interal force redistribution, the failure mode and the ultimate strength of the structure. The research results show that the deformation and interface slip increase and the bending capacity decreases with the reduction of shear connection, but it is less than the direct proportion of the reduction of shear connection. The bending capacity of two composite beams with the shear connection coefficient of 0. 7 was less than 10 percent compared with the full shear connection. The bending moment modulation value of continuous composite beams also decreases with the reduction of shear connection.%为探究剪力连接程度对预应力钢-混凝土连续组合梁的荷载-跨中挠度特征、沿梁纵向的相对滑移分布规律、沿截面高度的应变分布、预应力增量变化以及连续梁的内力重分布过程、破坏机理与极限强度等的影响,进行了4根预应力钢一混凝土连续组合梁的静载全过程试验研究.研究结果表明,随着剪力连接程度的降低,变形及界面滑移明显增大,承载能力有所降低,但降低程度小于剪力连接的降低程度,2根剪力连接程度系数为0.7的组合梁承载力比完全剪力连接组合梁均降低不到10％,随着剪力连接程度的降低连续梁相应弯矩的调幅值也会降低.
大跨度连续梁拱组合桥梁轨互制特征%Track-bridge Interaction of Combination Bridge with Long-span Continuous Beam Arch
Institute of Scientific and Technical Information of China (English)
王伟民
2016-01-01
To study the characteristics of track-beam interaction of the combination bridge with long-span continuous beam arch, a rigid frame arch combination bridge with (34+160+34) m continuous steel-box girder tied-arch on Meizhou-Chaoshan railway line is referenced. A track-arch-beam-pier integration space model is established to simulate track longitudinal resistance with ideal elastic-plastic model. The distribution of track longitudinal force is analyzed. The girder stress, the rotation angle at bridge end, and the longitudinal reaction at pier bottom are compared with or without track effects. Results show that rail longitudinal force is great at the beam end farther away from the fixed support of the combination bridge with continuous beam arch; the maximum expansion stress reaches to 114. 0 MPa, but the rail strength meets the requirements without rail expansion devices;the track structure has great impact on the stress of girder under the action of temperature load or braking force and it also has great impact on rotation angle at bridge end and on the distribution of longitudinal reaction at pier bottom.%为研究大跨度连续梁拱组合桥梁轨相互作用特征,以梅汕线上某(34+160+34) m刚架系杆拱钢箱连续梁组合桥为背景,采用理想弹塑性模型模拟线路纵向阻力,建立“轨拱梁墩”一体化空间模型,对钢轨纵向力的分布规律进行分析,对是否考虑轨道作用下的主梁应力、梁端转角、墩底纵向反力进行比较。结果表明：连续梁拱组合桥远离固定支座的梁端处钢轨纵向力较大,其中最大伸缩应力达到114.0 MPa,在不设钢轨伸缩调节器时钢轨强度仍满足要求；轨道结构对温度荷载和制动力作用下的主梁应力影响较大；轨道结构对梁端转角及墩底纵向反力的分配亦有较大影响。
Downsampling Non-Uniformly Sampled Data
Directory of Open Access Journals (Sweden)
Fredrik Gustafsson
2007-10-01
Full Text Available Decimating a uniformly sampled signal a factor D involves low-pass antialias filtering with normalized cutoff frequency 1/D followed by picking out every Dth sample. Alternatively, decimation can be done in the frequency domain using the fast Fourier transform (FFT algorithm, after zero-padding the signal and truncating the FFT. We outline three approaches to decimate non-uniformly sampled signals, which are all based on interpolation. The interpolation is done in different domains, and the inter-sample behavior does not need to be known. The first one interpolates the signal to a uniformly sampling, after which standard decimation can be applied. The second one interpolates a continuous-time convolution integral, that implements the antialias filter, after which every Dth sample can be picked out. The third frequency domain approach computes an approximate Fourier transform, after which truncation and IFFT give the desired result. Simulations indicate that the second approach is particularly useful. A thorough analysis is therefore performed for this case, using the assumption that the non-uniformly distributed sampling instants are generated by a stochastic process.
Statistical Test for Bivariate Uniformity
Directory of Open Access Journals (Sweden)
Zhenmin Chen
2014-01-01
Full Text Available The purpose of the multidimension uniformity test is to check whether the underlying probability distribution of a multidimensional population differs from the multidimensional uniform distribution. The multidimensional uniformity test has applications in various fields such as biology, astronomy, and computer science. Such a test, however, has received less attention in the literature compared with the univariate case. A new test statistic for checking multidimensional uniformity is proposed in this paper. Some important properties of the proposed test statistic are discussed. As a special case, the bivariate statistic test is discussed in detail in this paper. The Monte Carlo simulation is used to compare the power of the newly proposed test with the distance-to-boundary test, which is a recently published statistical test for multidimensional uniformity. It has been shown that the test proposed in this paper is more powerful than the distance-to-boundary test in some cases.
Hofmann, Steve
2012-01-01
We present a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, we establish scale invariant absolute continuity of harmonic measure with respect to surface measure, along with higher integrability of the Poisson kernel, for a domain $\\Omega\\subset \\re^{n+1},\\, n\\geq 2$, with a uniformly rectifiable boundary, which satisfies the Harnack Chain condition plus an interior (but not exterior) corkscrew condition. In a companion paper to this one \\cite{HMU}, we also establish a converse, in which we deduce uniform rectifiability of the boundary, assuming scale invariant $L^q$ bounds, with $q>1$, on the Poisson kernel.
Beam tests of phosphorescent screens
International Nuclear Information System (INIS)
Twelve phosphorescent screens were beam tested for linearity, uniformity, low radiation damage and a suitable emitted wavelength for use with television cameras. One screen was chosen for the construction of several intercepting profile monitors which were used during the SLC Ten Sector Tests to measure the emittance and wakefield effects of a damped electron beam
Uniform fuel target implosion in heavy ion inertial fusion
Kawata, S.; Karino, T.; Kondo, S.; Iinuma, T.; Barada, D.; Ma, Y. Y.; Ogoyski, A. I.
2016-05-01
For a steady operation of a fusion power plant the target implosion should be robust against the implosion non-uniformities. In this paper the non-uniformity mitigation mechanisms in the heavy ion beam (HIB) illumination are discussed in heavy ion inertial fusion (HIF). A density valley appears in the energy absorber, and the large-scale density valley also works as a radiation energy confinement layer, which contributes to the radiation energy smoothing for the HIB illumination non-uniformity. The large density-gradient scale, which is typically ∼500μm in HIF targets, also contributes to a reduction of the Rayleigh- Taylor instability growth rate. In HIF a wobbling HIBs illumination would also reduce the Rayleigh-Taylor instability growth and to realize a uniform implosion.
Uniform Acceleration in General Relativity
Friedman, Yaakov
2016-01-01
We extend de la Fuente and Romero's defining equation for uniform acceleration in a general curved spacetime from linear acceleration to the full Lorentz covariant uniform acceleration. In a flat spacetime background, we have explicit solutions. We use generalized Fermi-Walker transport to parallel transport the Frenet basis along the trajectory. In flat spacetime, we obtain velocity and acceleration transformations from a uniformly accelerated system to an inertial system. We obtain the time dilation between accelerated clocks. We apply our acceleration transformations to the motion of a charged particle in a constant electromagnetic field and recover the Lorentz-Abraham-Dirac equation.
Institute of Scientific and Technical Information of China (English)
李锟
2011-01-01
This paper makes an explanation about construction technology for bridge segment No. O, the cantilever casting segment, the cast-in-situ segment and the closure segment under cantilever casting construction of the Luoqingjiang extralarge bridge which is of pre-stressed continuous box girder type. It sums up the key technology for construction of continuous beam of the Luoqingjiang extra-large double line bridge.%详细介绍洛清江双线特大桥预应力砼连续箱梁悬臂灌筑的0号号段、悬灌段、现浇段及合龙段施工技术，从而总结出洛清江双线特大桥连续梁关键施工技术。
Institute of Scientific and Technical Information of China (English)
陈丽华; 李爱群; 娄宇; 李培彬
2009-01-01
Static load tests and bearing capacity analyses are cardeA out for two outer-plated steel-concrete continuous composite beams.The load-deflection curve and the loat-strain culve of specimens are obtained and analyzed.The test results indicate that effective cooperation can be achieved by the shear-resistant connection between the reinforcement in the negative moment area and the outer-plated steel beam,and the overall working performance of the composite beams is favorable.At the load-bearing limiting state,the plastic strain on the maximum negative and positive moment section becomes fully developed so as to form relatively ideal plastic hinges.With the increase in the reinforcement ratio,the moment-carrying capacity of the composite beams improves significantly,but the ductility of the beams and the rotation ability of the plastic hinges decrease.The formulae for calculating the limit bending capacity in the negative moment area of outer-plated steel-concrete composite beams are proposed based on the test data.The calculated results agree well with the test results.%对2根外包钢-混凝土连续梁试件进行了静力加载实验研究与承栽力分析.测量并分析了试件的荷栽-挠度及荷载-应变关系曲线.结果表明:外包钢-混凝土组合梁负弯矩区钢筋和外包钢梁通过抗剪连接措施能有效地共同工作,整体工作性能良好.在承栽能力极限状态,负弯矩和正弯矩最大截面的塑性应变均充分发展,并形成比较理想的塑性铰.随着配筋率的提高,组合梁受弯承栽力明显提高,而延性和转动能力相应降低.在试验数据基础上,给出了外包钢-混凝土组合梁在负弯矩区极限受弯承载力的计算公式,计算结果与实验结果吻合良好.
Institute of Scientific and Technical Information of China (English)
侯晓萌; 郑文忠
2011-01-01
A numerical model to simulate loading process of prestressed concrete（PC） continuous beams and slabs at elevated temperature is presented.It is considered that plane sections before bending remain plane after bending.Based on the thermal-mechanical coupling constitutive models of concrete,reinforcing and prestressing steels,the transient strain,creep strain in concrete at time t＋1 could be calculated by the stress in concrete at the former step.The coupled constitutive model of concrete could be decoupled,and the reinforcing and prestressing steels were calculated by the same way.Therefore,the moment-curvature relationships of PC beams and slabs subjected to fire can be calculated.The moment of flexure,deflection and support displacement of the beams and slabs imposed by curvature and support reaction together was calculated respectively.The support reaction was calculated by the iteration method until the deflection compatibility equation at the support was satisfied,and the deflection of continuous beams and slabs could be obtained.The deflection of PC continuous beams and slabs subjected to fire calculated by the computer program is verified by correlative fire resistance experiments.Through these studies,it is shown that support and span restraint effect has significant influence on the fire resistance of PC continuous beams and slabs.The mid-span deflection in side spans is larger than that in inner spans.%为模拟预应力混凝土连续梁板在火灾下的受力全过程,认为火灾下预应力混凝土梁板截面总应变符合平截面假定,基于混凝土、普通钢筋和预应力筋的耦合本构关系,用t时刻的混凝土应力计算t＋1时刻混凝土的瞬态热应变、高温徐变,钢筋与预应力筋采用相同的解耦方法,可求得火灾下预应力混凝土梁板的弯矩-曲率曲线;对支座反力进行迭代求解,计算梁板在曲率与支座反力共同作用下的弯矩、挠度和支座位移,直至支座位移满
Sckool Dress Rule, Uniform Policies
Institute of Scientific and Technical Information of China (English)
潘志强
2005-01-01
Our schools believe that a uniform policy will provide a better environment, promote positive selfesteem, encourage an atmosphere for greater discipline, and increase learning opportunities for students by removing many of the distractions associated with various types of clothing.
Institute of Scientific and Technical Information of China (English)
何永泉
2015-01-01
随着我国社会水平的提升，经济步伐的推进，我国的交通事业也在这个过程中得到了较大程度的发展。其中，连续梁拱组合桥梁是我国现今桥梁建设中非常重要的一个类型，近年来，已经有很多城市利用该种类型建设桥梁。本文将深入地研究分析连续梁拱组合桥梁上部结构施工关键技术，同时提出相应的政策建议。%With the ascension of social level and the progress of economic, the transportation industry of China also gets a larger degree of development in the process. The combination bridge of continuous beam-arc is a very important type in the current bridge construction of China. In recent years, there are many cities using this type to construct bridges. This paper deeply researches and analyzes the key construction technology of the superstructure of continuous beam-arch combination bridge and puts forward the related policy suggestions.
Institute of Scientific and Technical Information of China (English)
钟春玲; 叶增; 张云龙
2012-01-01
In the prestressed concrete bridge reinforcement, the application of the external prestressed gradually widely. This paper mainly based on differential equation deduced the external prestressed continuous beam in the vertical concentrated load dint method, the analytical solution of the equation. Using this theory calculation in the vertical deflection under concentrated load along the beam long distribution curve and Ansys numerical analysis re- suits are compared, and both have good consistency, it is shown that the result is reasonable and credible. Contrast the result indicates that the analytical solution and can get in the normal service condition the deflection of the con- crete beams, for the future analysis of the external prestressed carbon fiber reinforced the continuous girder provides the foundation.%在预应力混凝土桥梁加固中,体外预应力的应用逐渐广泛.本文主要基于微分方程,推导了体外预应力连续梁在竖向集中荷载作用下力法方程的解析解.利用该理论,计算了在竖向集中荷载作用下的挠度沿梁长的分布曲线,并与Ansys数值分析结果进行了对比,二者具有较好的一致性,说明该计算结果是合理的,可信的.对比结果表明,采用该解析解并能够得到在正常使用状态下混凝土梁的变形情况,为今后分析碳纤维加固体外预应力连续梁提供了基础.
Control of fuel target implosion non-uniformity in heavy ion inertial fusion
Iinuma, T; Kondo, S; Kubo, T; Kato, H; Suzuki, T; Kawata, S; Ogoyski, A I
2016-01-01
In inertial fusion, one of scientific issues is to reduce an implosion non-uniformity of a spherical fuel target. The implosion non-uniformity is caused by several factors, including the driver beam illumination non-uniformity, the Rayleigh-Taylor instability (RTI) growth, etc. In this paper we propose a new control method to reduce the implosion non-uniformity; the oscillating implosion acceleration dg(t) is created by pulsating and dephasing heavy ion beams (HIBs) in heavy ion inertial fusion (HIF). The dg(t) would reduce the RTI growth effectively. The original concept of the non- uniformity control in inertial fusion was proposed in (Kawata, et al., 1993). In this paper it was found that the pulsating and dephasing HIBs illumination provide successfully the controlled dg(t) and that dg(t) induced by the pulsating HIBs reduces well the implosion non-uniformity. Consequently the pulsating HIBs improve a pellet gain remarkably in HIF.
Construction Technology of Continuous Steel-concrete Joint Beam%连续钢-混结合梁施工技术
Institute of Scientific and Technical Information of China (English)
邓成杰
2014-01-01
本文结合重庆轨道交通一号线(沙大段)采用44.5+60+44.5 m 三跨连续钢-混结合箱梁跨越渝遂高速公路，介绍钢混连续结合梁的钢梁制作、吊装架设及混凝土桥面板一次现浇的施工方法。%This paper unifies the Chongqing rail transit line (Shada section) using 44.5+60+44.5m three span continuous steel-concrete composite box girder span Yusui expressway, introduces the steel concrete continuous girder fabrication, lifting the erection, concrete deck slab one cast construction method.
Determination of lead equivalent thickness and uniformity for Radiation Protective Gloves
International Nuclear Information System (INIS)
A procedure based on international standard and suited with our facilities was developed in our lab was used to determine lead equivalent thickness and uniformity of radiation protective gloves (RPG). Samples were sent by a Malaysian rubber glove manufacturer company for testing by using three narrow x-ray beam qualities with different size of collimators. Three types of x-ray beam quality were set-up with various thicknesses of copper filters. The calibration graphs were plotted for every X-ray beam qualities with different thickness of lead filters. Five points were selected for every sample in the uniformity test. Results are presented and shown that for lower beam quality, the lead equivalent thickness of the same samples are higher compare to higher beam quality. The uniformities of samples are not quite different for the selected points of the samples. (author)
Non-uniform Hyperbolicity and Non-uniform Specification
Oliveira, Krerley
2011-01-01
Let $f$ be a $C^{1+\\alpha}\\,(\\alpha>0)$ diffeomorphism and $\\mu$ be an ergodic hyperbolic measure of $f$. We show that this system $(f,\\mu)$ naturally satisfies non-uniform specification property\\cite{STV}(see Definition \\ref{Def:NS}) and thus we can delete the assumption of non-uniform specification property in the main Theorem \\cite{STV} to establish an inequality between Lyapunov exponents and local recurrence properties. We also discuss generalized non-uniform specification property with respect to arbitrarily finite(infinite) orbit segments. Moreover, these results are also valid for any ergodic hyperbolic measure $\\mu$, in whose Oseledec splitting the stable bundle dominates the unstable bundle on the support of $\\mu$.
Hofmann, Steve; Martell, José María
2012-01-01
We present a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, we establish scale invariant absolute continuity of harmonic measure with respect to surface measure, along with higher integrability of the Poisson kernel, for a domain $\\Omega\\subset \\mathbb{R}^{n+1},\\, n\\geq 2$, with a uniformly rectifiable boundary, which satisfies the Harnack Chain condition plus an interior (but not exterior) corkscrew condition. In a companion paper to th...
Institute of Scientific and Technical Information of China (English)
丁斌
2014-01-01
对4根玄武岩纤维布加固的混凝土 T 形截面连续梁和1根对比梁进行抗弯试验，分析了试验梁的破坏模式和各控制截面的弯矩调幅系数.试验结果表明：加固梁跨中截面纵筋屈服前，加固梁和对比梁各控制截面荷载-挠度曲线基本重合；跨中截面纵筋屈服后，加固梁发生了明显的弯矩重分布，跨中截面弯矩调幅系数为0.09~0.22，中支座截面弯矩调幅系数为0.15~0.38；1~3层纤维布加固梁荷载-挠度曲线具有屈服平台，表现出明显的延性破坏特征.%To analyze characteristics of moment redistribution of beams strengthened with BFRP sheets,flexural tests were conducted on one comparative continuous beam and four strengthened RC T-section continuous beams. Failure modes and modulation coefficients were analyzed. The results show that load versus displacement curves of control sections nearly overlap with each other before yielding of longitudinal rebar at mid-span. After the yielding of the rebar,obvious moment redistribution occurs. Moment modulation coefficients of the middle sup-port section ranges from 0. 09 to 0. 22. Moment modulation coefficients of the middle support section ranges from 0. 15 to 0. 38. Beams strengthened with one to three plies of BFRP sheets have a yielding platform in load versus displacement curves,and are subjected to obvious ductility failure.
Institute of Scientific and Technical Information of China (English)
丁斌
2014-01-01
To analyze characteristics of moment redistribution of beams strengthened with BFRP sheets,flexural tests were conducted on one comparative continuous beam and four strengthened RC T-section continuous beams. Failure modes and modulation coefficients were analyzed. The results show that load versus displacement curves of control sections nearly overlap with each other before yielding of longitudinal rebar at mid-span. After the yielding of the rebar,obvious moment redistribution occurs. Moment modulation coefficients of the middle sup-port section ranges from 0. 09 to 0. 22. Moment modulation coefficients of the middle support section ranges from 0. 15 to 0. 38. Beams strengthened with one to three plies of BFRP sheets have a yielding platform in load versus displacement curves,and are subjected to obvious ductility failure.%对4根玄武岩纤维布加固的混凝土 T 形截面连续梁和1根对比梁进行抗弯试验，分析了试验梁的破坏模式和各控制截面的弯矩调幅系数.试验结果表明：加固梁跨中截面纵筋屈服前，加固梁和对比梁各控制截面荷载-挠度曲线基本重合；跨中截面纵筋屈服后，加固梁发生了明显的弯矩重分布，跨中截面弯矩调幅系数为0.09~0.22，中支座截面弯矩调幅系数为0.15~0.38；1~3层纤维布加固梁荷载-挠度曲线具有屈服平台，表现出明显的延性破坏特征.
Institute of Scientific and Technical Information of China (English)
陶慕轩; 聂建国
2011-01-01
Based on the experimental results of six two-span prestressed continuous steel-concrete composite beams, an elaborate finite element model is proposed for simulating the nonlinear behavior of prestressed continuous composite beams using the commercial FE package MSC. MARC (2005r2). The procedures for element selection, material modeling and monolithic assembly are presented in detail, using an elasto-plastic constitutive model. The numerical model considering both the material and the geometric nonlinearities can fully reflect the complex characteristics such as the change of tendon force, slip effect, redistribution of internal force, stress distribution, curvature distribution, formation of plastic hinges, etc.. As the finite-element results are in good agreement with the test results and the theoretical analysis, the proposed finite-element model provides a tool for nonlinear analysis of prestressed continuous composite beams.%以六根两跨预应力钢-混凝土连续组合梁的系列试验结果为基础,以通用有限元程序MSC.MARC( 2005r2)为平台,提出用于模拟预应力连续组合梁非线性全过程受力行为的精细有限元模型,并给出单元选取、材料建模以及整体组装的详细过程.有限元分析基于弹塑性本构模型,能充分考虑材料非线性和几何非线性,反映结构受力全过程中预应力筋内力变化、滑移效应、内力重分布、应力分布、曲率分布以及塑性铰形成等复杂特性,深入揭示预应力连续组合梁的受力机理和特点.模型计算结果和实测结果以及理论分析结果吻合良好,表现出良好的数值特性.模型对于预应力连续组合梁的精细化分析具有较高的精度和广泛的适用性,为研究预应力连续组合梁受力性能提供了强有力的工具.
Uribe, Roberto M.; Filppi, Ed; Zhang, Shubo
2007-01-01
It is common to have liquid crystal displays and electronic circuit boards with area sizes of the order of 20x20 sq cm on board of satellites and space vehicles. Usually irradiating them at different fluence values assesses the radiation damage in these types of devices. As a result, there is a need for a radiation source with large spatial fluence uniformity for the study of the damage by radiation from space in those devices. Kent State University s Program on Electron Beam Technology has access to an electron accelerator used for both research and industrial applications. The electron accelerator produces electrons with energies in the interval from 1 to 5 MeV and a maximum beam power of 150 kW. At such high power levels, the electron beam is continuously scanned back and forth in one dimension in order to provide uniform irradiation and to prevent damage to the sample. This allows for the uniform irradiation of samples with an area of up to 1.32 sq m. This accelerator has been used in the past for the study of radiation damage in solar cells (1). However in order to irradiate extended area solar cells there was a need to measure the uniformity of the irradiation zone in terms of fluence. In this paper the methodology to measure the fluence uniformity on a sample handling system (linear motion system), used for the irradiation of research samples, along the irradiation zone of the above-mentioned facility is described and the results presented. We also illustrate the use of the electron accelerator for the irradiation of large area solar cells (of the order of 156 sq cm) and include in this paper the electrical characterization of these types of solar cells irradiated with 5 MeV electrons to a total fluence of 2.6 x 10(exp 15) e/sq cm.
Manufacturing uniform field silicon drift detector using double boron layer
International Nuclear Information System (INIS)
Novel SDDs with continuous junctions on both sides are fabricated using pure boron (PureB) depositions to create a shallow junction in the entrance window side and a continuous rectifying junction with different potentials as function of the drift coordinate in the device side. The SDDs made in this material offer lower leakage current. In addition, continuous SDD designed with two boron layers with different sheet resistances displays uniform electric field
Uniform excitations in magnetic nanoparticles
Directory of Open Access Journals (Sweden)
Steen Mørup
2010-11-01
Full Text Available We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering.
Harmonious coloring of uniform hypergraphs
Bartłomiej Bosek; Sebastian Czerwiński; Jarosław Grytczuk; Paweł Rzążewski
2016-01-01
A \\emph{harmonious coloring} of a $k$-uniform hypergraph $H$ is a vertex coloring such that no two vertices in the same edge share the same color, and each $k$-element subset of colors appears on at most one edge. The \\emph{% harmonious number} $h(H)$ is the least number of colors needed for such a coloring. %These notions arose as a natural extension of a widely studied %topic of harmonious coloring of simple graphs. We prove that $k$-uniform hypergraphs of bounded maxim...
Uniform excitations in magnetic nanoparticles
DEFF Research Database (Denmark)
Mørup, Steen; Frandsen, Cathrine; Hansen, Mikkel Fougt
2010-01-01
We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization...... and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering....
International Nuclear Information System (INIS)
Ion implantation's unique contributions to FET processing are excellent uniformity and repeatability at low dose. These could be verified on product wafers but were difficult to measure on monitor wafers. This paper presents an MOS technique that integrates the C-V curve directly to obtain part of the implanted dose - the partial dose. This technique is fast and insensitive to measurement noise and dot-diameter variation. It uses standard MOS wafers and processing. Neither photo-defined dots nor special substrates are required. Presently the integral CdV technique for partial dose is used in several FET lines to measure both implant repeatability and uniformity. (orig.)
Research of beam smoothing technologies using CPP, SSD, and PS
Zhang, Rui; Su, Jingqin; Hu, Dongxia; Li, Ping; Yuan, Haoyu; Zhou, Wei; Yuan, Qiang; Wang, Yuancheng; Tian, Xiaocheng; Xu, Dangpeng; Dong, Jun; Zhu, Qihua
2015-02-01
Precise physical experiments place strict requirements on target illumination uniformity in Inertial Confinement Fusion. To obtain a smoother focal spot and suppress transverse SBS in large aperture optics, Multi-FM smoothing by spectral dispersion (SSD) was studied combined with continuous phase plate (CPP) and polarization smoothing (PS). New ways of PS are being developed to improve the laser irradiation uniformity and solve LPI problems in indirect-drive laser fusion. The near field and far field properties of beams using polarization smoothing were studied and compared, including birefringent wedge and polarization control array. As more parameters can be manipulated in a combined beam smoothing scheme, quad beam smoothing was also studies. Simulation results indicate through adjusting dispersion directions of one-dimensional (1-D) SSD beams in a quad, two-dimensional SSD can be obtained. Experiments have been done on SG-III laser facility using CPP and Multi-FM SSD. The research provides some theoretical and experimental basis for the application of CPP, SSD and PS on high-power laser facilities.
Measuring Strain Response Mode Shapes with a Continuous-Scan LDV
Directory of Open Access Journals (Sweden)
Anthony B. Stanbridge
2002-01-01
Full Text Available A continuous-scan LDV is a convenient means for measuring the response mode shape (ODS of a vibrating surface, particularly in view of the fact that the ODS is automatically derived as a spatial polynomial series. Second spatial derivatives of the deflection equations are therefore easily derived, and these should, in principle, give curvature equations from which, for a beam or plate of known cross-section, stresses and strains can be obtained directly. Unfortunately, the stress and strain distributions depend critically on higher terms in the original ODS series, which are not accurately measured. This problem can be avoided by a method described here, which enables accurate stress and strain distributions to be derived, from a straight-line LDV scan along a uniform beam, using only five terms in the mode-shape polynomial series. A similar technique could be applied to uniform plates but the analysis and the governing equations are rather more complicated.
A RICH with aerogel: a study of refractive index uniformity
Alemi, M; Calvi, M; Matteuzzi, C; Musy, M; Perego, D L; Easo, S
2004-01-01
The use of aerogel as a radiator in the RICH detectors of LHCb is a challenge due to the hot environment of the hadron collider LHC. Large size tiles of silica aerogel were recently produced with unprecedented optical quality for such dimensions. Results of laboratory measurements and beam tests are briefly reported. A description of a method to measure the uniformity of the index of refraction within the tile is given.
School Uniforms: Guidelines for Principals.
Essex, Nathan L.
2001-01-01
Principals desiring to develop a school-uniform policy should involve parents, teachers, community leaders, and student representatives; beware restrictions on religious and political expression; provide flexibility and assistance for low-income families; implement a pilot program; align the policy with school-safety issues; and consider legal…
Institute of Scientific and Technical Information of China (English)
贾远林; 陈世鸣; 王新娣
2011-01-01
基于4根预应力连续组合梁试验,以通用非线性程序ABAQUS为平台,提出了用于模拟预应力连续组合梁非线性全过程受力行为的精细有限元模型.模型综合考虑了几何非线性、材料非线性、支座负弯矩区板件整体失稳和局部失稳等,不仅反映预应力连续组合梁整体性能,还模拟局部效应,深入揭示预应力筋内力变化、滑移效应、内力重分布、板件整体失稳及局部屈曲等复杂特性.通过对模型计算和实测结果的充分对比与校核,表明该模型用于预应力钢-混凝土连续组合梁的精细化分析具有较高精度和广泛通用性,表现出良好的数值特性,为研究预应力连续组合梁受力性能提供了强有力的数值工具.%Based on test analysis of four prestressed steel-concrete beams.allowing for the nonlinearity of geometry and material,the lateral distortional buckling and the plate local buckling a fine and exact finite element stimulation model by ABAQUS is established to study the the nonlinear development of beams, which reflects the overall behavior of the beam and catches the local effect, such as the stress varying in prestressed tendons, the slip, the redistribution of internal forces, the overall instability and local buckling. Compared the results by the FE model with the tests carefully and strictly, the FE model is of excellent numerical function with enoughaccuracy and versatility, which provides a powerful numeral tool for the research of continuous steel-concrete beams prestressed with external tendons.
A molecular beam epitaxy facility for in situ neutron scattering
International Nuclear Information System (INIS)
A molecular beam epitaxy (MBE) facility has been built to enable in situ neutron scattering measurements during growth of epitaxial layers. While retaining the full capabilities of a research MBE chamber, this facility has been optimized for polarized neutron reflectometry measurements. Optimization includes a compact lightweight portable design, a neutron window, controllable magnetic field, deposition across a large 76 mm diameter sample with exceptional flux uniformity, and sample temperatures continuously controllable from 38 to 1375 K. A load lock chamber allows for sample insertion, storage of up to 4 samples, and docking with other facilities. The design and performance of this chamber are described here.
Uniformity Analysis for Index of Retail Price
Institute of Scientific and Technical Information of China (English)
潘竞红; 曾庆洪; 刘梅英
2002-01-01
Using the Hodges-Ajne testing method, the uniformity of China retail price index was tested. The result, that population is submitting to uniform dist ribution, was obtained. The uniformity of CRPI indicates that the general price level is stable in the Ninth Five-Year Plan. Finally, the reasons causing the uniformity was analyzed.
Uniform pricing and social welfare
Bertoletti, Paolo
2005-01-01
We re-examine the case for uniform pricing in a monopolistic third-degree price-discrimination setting by introducing differentiated costs. A profit-maximizing monopolist could then use price differentiation to reduce the production of the more costly goods, thereby decreasing average cost and increasing welfare. Indeed, monopolistic price differentiation can improve welfare and also aggregate consumer surplus even if, as in the benchmark linear case, total output does not increase. According...
Energy Technology Data Exchange (ETDEWEB)
Blue, C.A.; Sikka, V.K. [Oak Ridge National Lab., TN (United States); Chun, Jung-Hoon [Massachusetts Institute of Technology, Cambridge, MA (United States); Ando, T. [Tufts Univ., Medford, MA (United States)
1997-04-01
The uniform-droplet process is a new method of liquid-metal atomization that results in single droplets that can be used to produce mono-size powders or sprayed-on to substrates to produce near-net shapes with tailored microstructure. The mono-sized powder-production capability of the uniform-droplet process also has the potential of permitting engineered powder blends to produce components of controlled porosity. Metal and alloy powders are commercially produced by at least three different methods: gas atomization, water atomization, and rotating disk. All three methods produce powders of a broad range in size with a very small yield of fine powders with single-sized droplets that can be used to produce mono-size powders or sprayed-on substrates to produce near-net shapes with tailored microstructures. The economical analysis has shown the process to have the potential of reducing capital cost by 50% and operating cost by 37.5% when applied to powder making. For the spray-forming process, a 25% savings is expected in both the capital and operating costs. The project is jointly carried out at Massachusetts Institute of Technology (MIT), Tuffs University, and Oak Ridge National Laboratory (ORNL). Preliminary interactions with both finished parts and powder producers have shown a strong interest in the uniform-droplet process. Systematic studies are being conducted to optimize the process parameters, understand the solidification of droplets and spray deposits, and develop a uniform-droplet-system (UDS) apparatus appropriate for processing engineering alloys.
Uniform Practical Nonlinear Output Regulation
Marconi, Lorenzo; Praly, Laurent
2008-01-01
International audience In this paper, we present a solution to the problem of asymptotic and practical semiglobal regulation by output feedback for nonlinear systems. A key feature of the proposed approach is that practical regulation is achieved uniformly with respect to the dimension of the internal model and to the gain of the stabilizer near the zero error manifold. This property renders the approach interesting for a number of real cases by bridging the gap between output regulation t...
Calorimetry of electron beams and the calibration of dosimeters at high doses
Humphreys, J. C.; McLaughlin, W. L.
Graphite or metal calorimeters are used to make absolute dosimetric measurements of high-energy electron beams. These calibrated beams are then used to calibrate several types of dosimeters for high-dose applications such as medical-product sterilization, polymer modification, food processing, or electronic-device hardness testing. The electron beams are produced either as continuous high-power beams at approximately 4.5 MeV by d.c. type accelerators or in the energy range of approximately 8 to 50 MeV using pulsed microwave linear accelerators (linacs). The continuous beams are generally magnetically scanned to produce a broad, uniform radiation environment for the processing of materials of extended lateral dimensions. The higher-energy pulsed beams may also be scanned for processing applications or may be used in an unscanned, tightly-focused mode to produce maximum absorbed dose rates such as may be required for electronic-device radiation hardness testing. The calorimeters are used over an absorbed dose range of 10 2 to 10 4 Gy. Intercomparison studies are reported between National Institute of Standards and Technology (NIST) and UK National Physical Laboratory (NPL) graphite disk calorimeters at high doses, using the NPL 10-MeV linac, and agreement was found within 1.5%. It was also shown that the electron-beam responses of radiochromic film dosimeters and alanine pellet dosimeters can be accurately calibrated by comparison with calorimeter readings.
Beam-beam observations in the Relativistic Heavy Ion Collider
Energy Technology Data Exchange (ETDEWEB)
Luo, Y. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States); White, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)
2015-06-24
The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.
NAJI, Noor Ezzulddin
2011-01-01
Presented is a derivation of an analytical expression for the mode-coherence coefficients of uniform-distributed wave propagating within different homogeneous media-as in the case of hyperbolic Gaussian beams-and a simple method involving the superposition of two such beams is proposed. The results obtained from this work are very applicable to study and analysis of Hermite-Gaussian beam propagation, especially in the problems of radiation-matter interaction, and laser beam propagatio...
Institute of Scientific and Technical Information of China (English)
田春香
2015-01-01
Research purposes:If ballastless track was laid on long -span bridges,the gradient,span and temperature change of bridge will have impact on force of fasteners at beam end.A finite element model which could calculate the force of fasteners on sloping bridges was established.The influences of bridge gradient,temperature variation, temperature span and the layout of fixed bearing of the adjacent simply supported beam bridge on fastener force were analyzed with the model.The maximum gradients of continuous beam bridges with different height piers and temperature spans were determined based on the fastener force under the disadvantageous load effect combination which might occur during the operation.The value could provide theoretical guidance for the design of ballastless track on long -span bridges in mountainous area. Research conclusions:(1 )The influence of the gradient of bridge on the direction of fasteners force should be considered when calculating the fastener force affected by the deformation of sloping bridge.(2)With the increasing of gradient,the temperature variation and the temperature span,the maximum additional force of fasteners increases linearly.The configuration with the fixed bearing of simply supported bridge adjacent to the continuous beam bridge laying on the direction of fall is beneficial to the fastener.(3)In order to make sure that the fastener force does not exceed the limit value under disadvantageous load effect combination,the maximum gradients of continuous beam bridges with different height piers and temperature spans are acquired,and the laying transition slab between the ends of two beams can increase the maximum gradients.(4)The results can be used to guide the design of bridge and ballastless track.%研究目的：大跨桥梁上铺设无砟轨道时，桥梁坡度、桥梁跨度及梁体温度变化会对梁端扣件受力产生影响，本文通过建立坡度桥梁扣件受力分析计算的有限元模型，研
Hofmann, Steve; Uriarte-Tuero, Ignacio
2012-01-01
We present the converse to a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, for $n\\geq 2$, for an ADR domain $\\Omega\\subset \\re^{n+1}$ which satisfies the Harnack Chain condition plus an interior (but not exterior) Corkscrew condition, we show that absolute continuity of harmonic measure with respect to surface measure on $\\partial\\Omega$, with scale invariant higher integrability of the Poisson kernel, is sufficient to imply uniformly rectifiable of $\\partial\\Omega$.
Institute of Scientific and Technical Information of China (English)
陈麟
2012-01-01
以哈大客运专线连续梁桥为实例,对桥梁结构不同工况、阶段进行分析.在对影响桥梁长期变形的主要因素进行总结的基础上,针对那些实际施工中常被人为左右或容易被忽视的因素的影响,给出必要的提醒和建议(或施工要点).深入了解并把握连续梁桥在这些工况下的徐变特性及其变化规律,将有助于制定正确的施工组织方案,在工期、征地拆迁、地质、水文、气候、材料供应等因素变化,甚至不同专业在狭长的桥上空间交错作业影响时,采取科学合理的技术措施将这些因素所带来的影响降至最低.%This paper analyzes the different operating conditions and different stages of bridge structure in combination with the example of the continuous Beam bridge in Harbin-Dalian Passenger-Dedicated Railway. The necessary reminders and suggests ( or construction key points) which are frequently man-made or neglected are provided, through summarizing the main influencing factors on long-term bridge deformation during actual construction. It is significant to understand and master the creep properties and creep variations of continuous Beam bridge, under the changed conditions such as the construction period, land acquisition, geology, hydrology, climate, material supplies, even under the condition that different professional works are operated simultaneously on the long and narrow bridge, for the purpose of developing the reasonable construction organization plan and technical measures, so as to minimize their adverse impacts.
Thomas Precession by Uniform Acceleration
Pardy, Miroslav
2015-01-01
We determine the nonlinear transformations between coordinate systems which are mutually in a constant symmetrical accelerated motion. The maximal acceleration limit follows from the kinematical origin and it is an analogue of the maximal velocity in special relativity. We derive the dependence of mass, length, time, Doppler effect, Cherenkov effect and transition radiation angle on acceleration as an analogue phenomena in special theory of relativity. The last application of our method is the Thomas precession by uniform acceleration with the possible role in the modern physics and cosmology. The comparison of derived results with other relativistic methods is necessary.
Mask CD uniformity improvement by electron scanning exposure based Global Loading Effect Correction
Li, Rivan; Tian, Eric; Shi, Irene; Guo, Eric; Lu, Max
2015-07-01
Critical Dimension (CD) Uniformity is one of the necessary parameters to assure good performance and reliable functionality of any integrated circuit (IC), and towards the advanced technology node 28nm and beyond, corresponding CD Uniformity becomes more and more crucial. It is found that bad mask CD Uniformity is a significant error source at 28nm process. The CD Uniformity on mask, if not controlled well, will badly impact wafer CD performance, and it has been well-studied that CD Uniformity issue from gate line-width in transistors would affect the device performance directly. In this paper we present a novel solution for mask global CD uniformity error correction, which is called as global loading effect correction (GLEC) method and applied nesting in the mask exposure map during the electron beam exposure. There are factors such as global chip layout, writing sequence and chip pattern density distribution (Global Loading), that work on the whole mask CD Uniformity, especially Global Loading is the key factor related to mask global CD error. From our experimental results, different pattern density distribution on mask significantly influenced the final mask CD Uniformity: the mask with undulating pattern density distribution provides much worse CD Uniformity than that with uniform one. Therefore, a GLEC model based on pattern density has been created to compensate the global error during the electron beam exposure, which has been proved to be efficacious to improve mask global CD Uniformity performance. Furthermore, it 's also revealed that pattern type is another important impact factor, and GLEC coefficient need be modified due to the specific pattern type (e.g. dense line-space only, iso-space only or an average of them) to improve the corresponding mask CD uniformity.
McDonald, Kirk T
2000-01-01
Scalar Bessel beams are derived both via the wave equation and via diffraction theory. While such beams have a group velocity that exceeds the speed of light, this is a manifestation of the "scissors paradox" of special relativty. The signal velocity of a modulated Bessel beam is less than the speed of light. Forms of Bessel beams that satisfy Maxwell's equations are also given.
Harriott, Lloyd R.
1997-04-01
Electron beams have played a significant role in semiconductor technology for more than twenty years. Early electron beam machines used a raster scanned beam spot to write patterns in electron-sensitive polymer resist materials. The main application of electron beam lithography has been in mask making. Despite the inherently high spatial resolution and wide process margins of electron beam lithography, the writing rate for semiconductor wafers has been too slow to be economically viable on a large scale. In the late 1970's, variable shape electron beam writing was developed, projecting a rectangular beam whose size can be varied for each "shot" exposure of a particular pattern, allowing some integrated circuits to be made economically where a variety of "customized" patterns are desired. In the cell or block projection electron beam exposure technique, a unit cell of a repetitive pattern is projected repeatedly to increase the level of parallelism. This can work well for highly repetitive patterns such as memory chips but is not well suited to complex varying patterns such as microprocessors. The rapid progress in the performance of integrated circuits has been largely driven by progress in optical lithography, through improvements in lens design and fabrication as well as the use of shorter wavelengths for the exposure radiation. Due to limitations from the opacity of lens and mask materials, it is unlikely that conventional optical printing methods can be used at wavelengths below 193 nm or feature sizes much below 180 nm. One candidate technology for a post-optical era is the Scattering with Angular Limitation Projection Electron-beam Lithography (SCALPEL) approach, which combines the high resolution and wide process latitude inherent in electron beam lithography with the throughput of a parallel projection system. A mask consisting of a low atomic number membrane and a high atomic number pattern layer is uniformly illuminated with high energy (100 ke
Electron beam experiments at Maryland University
International Nuclear Information System (INIS)
An experimental study of the stability of intense electron beams is described. The purpose is to determine the emittance growth associated with aberrations arising from the non-uniform transverse density distribution in the beam, and to compare measurements with the results of computer simulations
Calculation of the Ability of Rotation of Plastic Hinge in RC Continuous Beam%钢筋混凝土连续梁塑性铰转动能力的计算
Institute of Scientific and Technical Information of China (English)
曾德光; 周东华; 韦俊峰
2012-01-01
在考虑塑性的结构分析中,结构破坏标志是结构中出现了足够多的塑性铰,结构变成可变体系,从而破坏.因此,结构中出现的第一个塑性铰必须有足够的转动能力,以保证在继续加载后,其他截面也出现塑性铰.利用有限元法对钢筋混凝土连续梁的塑性铰转动能力进行计算,以确定结构出现的第一个塑性铰有足够的转动能力.%In the Structural Plasticity Analysis, the symbol of structural fracture is that there are enough plastic hinges in the structure, the structure is geometrically unstable system and fracture. The first plastic hinge must have the ability of rotation to make sure that there are plastic hinges on the other sections under the load. The ability of rotation of plastic hinge in RC continuous beam with the finite element method to ensure that the ability of rotation of the first plastic hinge is enough.
Institute of Scientific and Technical Information of China (English)
郭莹; 姚勇
2011-01-01
为了解德阳市王官村互通式立交桥在荷载作用下的实际工作状态,对该桥梁进行了静动荷载试验.试验首先基于通用有限元程序软件进行理论计算,并根据理论计算结果作为控制因素进行现场检测试验,并对检测过程及该桥使用状况进行总结分析.试验结果表明,该桥使用性能较好,处于弹性工作状态,承载能力满足有关规范的要求.%To understand the real work condition of interoperability overpass continuous beam in Wangguan Village of Deyang on the loading, the static/dynamic load tests have been carried out. We firstly computed the theory consequence based on the procedure software in general, and then actually tested the bridge by comparing with the theory effect. There are some reasonable analysis about the loading procedure and the back use. The result shows that usage function of approach structure is better,the loading ability satisfy with the request of our country normative.
Square shaped flat-top beam in refractive beam shapers
Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei
2015-08-01
Lossless transformation of round Gaussian to square shaped flat-top collimated beam is important in building highpower solid state laser systems to improve optical pumping or amplification. There are industrial micromachining applications like scribing, display repair, which performance is improved when a square shaped spot with uniform intensity is created. Proved beam shaping solutions to these techniques are refractive field mapping beam shapers having some important features: flatness of output phase front, small output divergence, high transmittance, extended depth of field, operation with TEM00 and multimode lasers. Usual approach to design refractive beam shapers implies that input and output beams have round cross-section, therefore the only way to create a square shaped output beam is using a square mask, which leads to essential losses. When an input laser beam is linearly polarized it is suggested to generate square shaped flat-top output by applying beam shaper lenses from birefringent materials or by using additional birefringent components. Due to birefringence there is introduced phase retardation in beam parts and is realized a square shaped interference pattern at the beam shaper output. Realization of this approach requires small phase retardation, therefore weak birefringence effect is enough and birefringent optical components, operating in convergent or divergent beams, can be made from refractive materials, which crystal optical axis is parallel to optical axis of entire beam shaper optical system. There will be considered design features of beam shapers creating square shaped flat-top beams. Examples of real implementations and experimental results will be presented as well.
Polychromatic and rotating beams of light
International Nuclear Information System (INIS)
Beams of light with rotating polarization or mode patterns can be viewed as superpositions of components with a well-defined angular momentum ℎm per photon, each having a frequency shift m times the rotation frequency. Such beams can also be created after passing a monochromatic beam through rotating optical elements. We discuss the properties of the angular momentum of such beams, both for a rotating polarization and a rotating amplitude pattern. We also consider beams where the polarization is not uniform
Dense packing on uniform lattices
Eloranta, Kari
2009-01-01
We study the Hard Core Model on the graphs ${\\rm {\\bf \\scriptstyle G}}$ obtained from Archimedean tilings i.e. configurations in $\\scriptstyle \\{0,1\\}^{{\\rm {\\bf G}}}$ with the nearest neighbor 1's forbidden. Our particular aim in choosing these graphs is to obtain insight to the geometry of the densest packings in a uniform discrete set-up. We establish density bounds, optimal configurations reaching them in all cases, and introduce a probabilistic cellular automaton that generates the legal configurations. Its rule involves a parameter which can be naturally characterized as packing pressure. It can have a critical value but from packing point of view just as interesting are the noncritical cases. These phenomena are related to the exponential size of the set of densest packings and more specifically whether these packings are maximally symmetric, simple laminated or essentially random packings.
Uniform magnetic excitations in nanoparticles
DEFF Research Database (Denmark)
Mørup, Steen; Hansen, Britt Rosendahl
2005-01-01
We have used a spin-wave model to calculate the temperature dependence of the (sublattice) magnetization of magnetic nanoparticles. The uniform precession mode, corresponding to a spin wave with wave vector q=0, is predominant in nanoparticles and gives rise to an approximately linear temperature...... dependence of the (sublattice) magnetization well below the superparamagnetic blocking temperature for both ferro-, ferri-, and antiferromagnetic particles. This is in accordance with the results of a classical model for collective magnetic excitations in nanoparticles. In nanoparticles of antiferromagnetic...... materials, quantum effects give rise to a small deviation from the linear temperature dependence of the (sublattice) magnetization at very low temperatures. The complex nature of the excited precession states of nanoparticles of antiferromagnetic materials, with deviations from antiparallel orientation...
Attitudes of Parents about School Uniforms.
West, Charles K.; Tidwell, Diane K.; Bomba, Anne K.; Elmore, Patsy Alexander
1999-01-01
Responses from 144 parents of fourth graders showed that 56% favored uniforms in public schools; most agreed that uniforms contributed to a conducive learning environment, promoted school spirit, and discouraged violence; and most disagreed that uniforms cost more than other types of clothing. (SK)
Application of the Differential Quadrature Method to the Longitudinal Vibration of Non-Uniform Rods
Al Kaisy, A.M.A.; Esmaeel, Ramadan A; Nassar, Mohamed M.
2007-01-01
Differential Quadrature Method (DQM) has a very wide applications in the field of structural vibration of various elements such as beams, plates, cylindrical shells and tanks. One of the most advantages of the DQM is its simple forms for nonlinear formulations using the Hadamard product. In this paper the free vibration of a general non-uniform rod were studied. The non-dimensional natural frequency and the normalized mode shapes of the non-uniform rod of free and clamped boundary conditions ...
Campargue, Roger
2005-05-01
This Historical Account derived in part from D. R. Herschbach was presented as an opening lecture of the Molecular Beam Session organized at the 24th International Symposium on Rarefied Gas Dynamics held in Bari, Italy, in July 2004. The emphasis is on the impressive results due to the molecular beam techniques in the last century. The first section summarizes the historical beam experiments performed by 14 Nobel Prize laureates having used the thermally effusive sources to establish the basic principles of Modern Physics. The second section is on the branching of Molecular Beams to Rarefied Gas Dynamics having permitted to investigate the physics of supersonic free jets and transform the molecular beam techniques. Finally, the last section relates the spectacular molecular beam experiments in helium free jet ultracooling, molecular spectroscopy, chemical reaction dynamics, clustering and modification of low density matter, and biomolecule mass spectrometry, rewarded by nine Nobel Prizes in Chemistry from 1986 to 2002.
Coherence delay augmented laser beam homogenizer
Rasmussen, P.; Bernhardt, A.
1993-06-29
The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.
Response Uniformity of the ATLAS Liquid Argon Electromagnetic Calorimeter
Aharrouche, M; Di Ciaccio, L; El Kacimi, M; Gaumer, O; Gouanère, M; Goujdami, D; Lafaye, R; Laplace, S; Le Maner, C; Neukermans, L; Perrodo, P; Poggioli, L; Prieur, D; Przysiezniak, H; Sauvage, G; Wingerter-Seez, I; Zitoun, R; Lanni, F; Lü, L; Ma, H; Rajagopalan, S; Takai, H; Belymam, A; Benchekroun, D; Hakimi, M; Hoummada, A; Gao, Y; Stroynowsk, R; Aleksa, M; Carli, T; Fassnacht, P; Gianotti, F; Hervás, L; Lampl, W; Collot, J; Hostachy, J Y; Ledroit-Guillon, F; Malek, F; Martin, P; Viret, S; Leltchouk, M; Parsons, J A; Simion, S; Barreiro, F; Del Peso, J; Labarga, L; Oliver, C; Rodier, S; Barrillon, P; Benchouk, C; Djama, F; Hubaut, F; Monnier, E; Pralavorio, P; Sauvage, D; Serfon, C; Tisserant, S; Tóth, J; Banfi, D; Carminati, L; Cavalli, D; Costa, G; Delmastro, M; Fanti, M; Mandell, L; Mazzanti, M; Tartarelli, F; Kotov, K; Maslennikov, A; Pospelov, G; Tikhonov, Yu; Bourdarios, C; Fayard, L; Fournier, D; Iconomidou-Fayard, L; Kado, M; Parrour, G; Puzo, P; Rousseau, D; Sacco, R; Serin, L; Unal, G; Zerwas, D; Dekhissi, B; Derkaoui, J; EL Kharrim, A; Maaroufi, F; Cleland, W; Lacour, D; Laforge, B; Nikolic-Audit, I; Schwemling, Ph; Ghazlane, H; Cherkaoui El Moursli, R; Idrissi Fakhr-Eddine, A; Boonekamp, M; Kerschen, N; Mansoulié, B; Meyer, P; Schwindlingy, J; Lund-Jensen, B
2007-01-01
The construction of the ATLAS electromagnetic liquid argon calorimeter modules is completed and all the modules are assembled and inserted in the cryostats. During the production period four barrel and three endcap modules were exposed to test beams in order to assess their performance, ascertain the production quality and reproducibility, and to scrutinize the complete energy reconstruction chain from the readout and calibration electronics to the signal and energy reconstruction. It was also possible to check the full Monte Carlo simulation of the calorimeter. The analysis of the uniformity, resolution and extraction of constant term is presented. Typical non-uniformities of 0.5% and typical global constant terms of 0.6% are measured for the barrel and end-cap modules.
Some results on uniform arithmetic circuit complexity
DEFF Research Database (Denmark)
Frandsen, Gudmund Skovbjerg; Valence, Mark; Barrington, David A. Mix
1994-01-01
and polynomial-size unbounded fan-in arithmetic circuits satisfying a natural uniformity constraint (DLOGTIME-uniformity). A 1-input and 1-output arithmetic function over the fieldsF2n may be identified with ann-input andn-output Boolean function when field elements are represented as bit strings. We prove...... that if some such representation is X-uniform (where X is P or DLOGTIME), then the arithmetic complexity of a function (measured with X-uniform unbounded fan-in arithmetic circuits) is identical to the Boolean complexity of this function (measured with X-uniform threshold circuits). We show the existence...
Barnsley, Michael F.; Vince, Andrew
2012-01-01
A fractal function is a function whose graph is the attractor of an iterated function system. This paper generalizes analytic continuation of an analytic function to continuation of a fractal function.
Design and performance of high uniformity linear filament electron gun
Iqbal, Munawar; Fazal-e-Aleem
2006-10-01
We describe new features and results from the previously reported [M. Iqbal et al., Rev. Sci. Instrum. 74, 4616 (2003)] thermionic long (up to 140mm) cathode, electromagnetically focused electron beam gun. The gun which was tested up to 50kW (5000mA×10kV) achieves power density of 33kW/cm2 at the target. The cathode temperature and emission current was uniform over a length of 100mm of the cathode. The beam density profile along the line cathode strongly relates to the temperature distribution along the line cathode. The gun has a remarkable application in heat treatment of large surface area and to coat large substrate surfaces at much faster evaporation rates with lower cost.
Illumination uniformity requirements for direct drive inertial confinement fusion
International Nuclear Information System (INIS)
The requirements for laser uniformity are discussed in terms of the ell-mode spectrum. It is shown that the choice of smoothing methods can significantly alter this spectrum and that this choice should be made in the context of the target physics. Although two dimensional smoothing by spectral dispersion yields a high quality near field beam profile, it results in poor smoothing for low spatial frequency. The partially coherent light method (fiber smoothing) leads to superior smoothing at low spatial frequencies, but has very poor near field beam quality. As a result, it may be desirable to use partially coherent light during the driver pulse foot (at low intensity and when minimizing the laser imprint is critical) and smoothing by spectral dispersion during the main pulse
A note on the complementarity of uniform emission standards and monitoring strategies.
Rousseau, Sandra; Arguedas, Carmen
2009-01-01
Despite the well-known static cost-inefficiency of uniform emission standards to control pollution, governments continue to use them in a variety of settings. In this paper, we show that inspection agencies can sometimes use their informational advantage to design monitoring strategies that complement uniform emission standards in restoring efficiency.
Discovery of Uniformly Expanding Universe
Directory of Open Access Journals (Sweden)
Cahill R. T.
2012-01-01
Full Text Available Saul Perlmutter and the Brian Schmidt – Adam Riess teams reported that their Friedmann-model GR-based analysis of their supernovae magnitude-redshift data re- vealed a new phenomenon of “dark energy” which, it is claimed, forms 73% of the energy / matter density of the present-epoch universe, and which is linked to the further claim of an accelerating expansion of the universe. In 2011 Perlmutter, Schmidt and Riess received the Nobel Prize in Physics “for the discovery of the accelerating ex- pansion of the Universe through observations of distant supernovae”. Here it is shown that (i a generic model-independent analysis of this data reveals a uniformly expanding universe, (ii their analysis actually used Newtonian gravity, and finally (iii the data, as well as the CMB fluctuation data, does not require “dark energy” nor “dark matter”, but instead reveals the phenomenon of a dynamical space, which is absent from the Friedmann model.
Non-paraxial Elliptical Gaussian Beam
Institute of Scientific and Technical Information of China (English)
WANG Zhaoying; LIN Qiang; NI Jie
2001-01-01
By using the methods of Hertz vector and angular spectrum transormation, the exact solution of non-paraxial elliptical Gaussion beam with general astigmatism based on Maxwell′s equations is obtained. We discussed its propagation characteristics. The results show that the orientation of the elliptical beam spot changes continuously as the beam propagates through isotropic media. Splitting or coupling of beam spots may occur for different initial spot size. This is very different from that of paraxial elliptical Gaussian beam.
Multi beam laser target illumination
International Nuclear Information System (INIS)
In order to compress matter to high densities by the application of intense pulses of laser energy it is necessary for the implosion of the target to be both stable and spherical. This imposes certain constraints on the uniformity of illumination of the target, and, this in turn places requirements on the illuminating optics and the laser beam quality. This report discusses the uniformity of illumination of a spherical target as provided by a variety of optical systems and for different numbers of laser beams and beam profiles. The results are compared with similar conclusions obtained by other workers. An alternative presentation of the calculations is given which is believed to be a more realistic estimate of the uniformity. Comments are made on the approximations that have been assumed and the results likely to be obtained from the full treatment are discussed. The effects of this non-uniform illumination on the target implosion are considered using the linear theory of the Rayleigh-Taylor instability. Finally, comments are made on other factors of a more practical nature which also govern the final choice of illumination system and the scope of experiments made possible by such a system. (author)
Report for muon production target with the 300-kW proton beam operation at MUSE/MLF/J-PARC
International Nuclear Information System (INIS)
The most intense pulsed muon beam will be generated by a 3-GeV 333-microA proton beam on a muon target made of 20-mm thick isotropic graphite (IG-430) in J-PARC/MUSE (Muon Science Establishment). The energy deposited by a 1-MW proton beam is estimated to be 3.9 kW on the muon target. The first muon beam was successfully generated on September 26th, 2008. Gradually upgrading the beam intensity, continuous 300-kW proton beam operation was started in January of 2013. The temperatures of the principle components have been measured and recorded through thermocouples and a control system. The lifetime of the muon target is determined by a proton-irradiation damage of the graphite. Even in the 300-kW operation to July of 2013, the radiation damage was anticipated to surpass the lifetime. Therefore, the position of the proton beam has been moved to eight surrounding positions every three weeks to distribute the radiation damage uniformly to a wider area. The position-control is named EXILE operation. The variation of the temperatures at the muon target has been monitored. In this report, the status of proton beam operation and the lifetime extension of the muon target will be described. (author)
Tian, Chao; Chen, Jia; Zhang, Bo; Shan, Lianqiang; Zhou, Weimin; Liu, Dongxiao; Bi, Bi; Zhang, Feng; Wang, Weiwu; Zhang, Baohan; Gu, Yuqiu
2015-05-01
The uniformity of the compression driver is of fundamental importance for inertial confinement fusion (ICF). In this paper, the illumination uniformity on a spherical capsule during the initial imprinting phase directly driven by laser beams has been considered. We aim to explore methods to achieve high direct drive illumination uniformity on laser facilities designed for indirect drive ICF. There are many parameters that would affect the irradiation uniformity, such as Polar Direct Drive displacement quantity, capsule radius, laser spot size and intensity distribution within a laser beam. A novel approach to reduce the root mean square illumination non-uniformity based on multi-parameter optimizing approach (particle swarm optimization) is proposed, which enables us to obtain a set of optimal parameters over a large parameter space. Finally, this method is applied to improve the direct drive illumination uniformity provided by Shenguang III laser facility and the illumination non-uniformity is reduced from 5.62% to 0.23% for perfectly balanced beams. Moreover, beam errors (power imbalance and pointing error) are taken into account to provide a more practical solution and results show that this multi-parameter optimization approach is effective. PMID:25969321
International Nuclear Information System (INIS)
Non-neutral electron plasmas confined in a uniform magnetic field can be used to simulate a beam dynamics in a uniform focusing channel. Here, a halo formation due to a mismatch induced on an electric confinement potential (harmonic potential) is reported. A beam halo is measured with a conventional beam imaging system composed of a phosphor screen and a charge-coupled device (CCD) camera. Obtained results show that the growth rate of a halo is a few tens microseconds in the present experimental condition. (author)
Uniformly balanced words with linear complexity and prescribed letter frequencies
Directory of Open Access Journals (Sweden)
Valérie Berthé
2011-08-01
Full Text Available We consider the following problem. Let us fix a finite alphabet A; for any given d-uple of letter frequencies, how to construct an infinite word u over the alphabet A satisfying the following conditions: u has linear complexity function, u is uniformly balanced, the letter frequencies in u are given by the given d-uple. This paper investigates a construction method for such words based on the use of mixed multidimensional continued fraction algorithms.
School uniforms: tradition, benefit or predicament?
Van Aardt, Annette Marie; Wilken, Ilani
2012-01-01
This article focuses on the controversies surrounding school uniforms. Roleplayers in this debate in South Africa are parents, learners and educators, and arguments centre on aspects such as identity, economy and the equalising effect of school uniforms, which are considered in the literature to be benefits. Opposing viewpoints highlight the fact that compulsory uniforms infringe on learners’ constitutional rights to self-expression. The aim of this research was to determine the perspectives ...
Continuously variable focal length lens
Adams, Bernhard W; Chollet, Matthieu C
2013-12-17
A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.
On the Compactly Locally Uniformly Rotund Points of Orlicz Spaces
Indian Academy of Sciences (India)
Lili Chen; Yunan Cui
2007-11-01
In this paper, locally uniformly rotund points and compactly locally uniformly rotund points are introduced. Moreover, criteria for compactly locally uniformly rotund points in Orlicz spaces are given.
Beam - cavity interaction beam loading
International Nuclear Information System (INIS)
The interaction of a beam with a cavity and a generator in cyclic accelerators or storage rings is investigated. Application of Maxwell's equations together with the nonuniform boundary condition allows one to get an equivalent circuit for a beam-loaded cavity. The general equation for beam loading is obtained on the basis of the equivalent circuit, and the beam admittance is calculated. Formulas for power consumption by a beam-loaded cavity are derived, and the optimal tuning and coupling factor are analyzed. (author)
Keller, Kristin; Tabacchi, Jo
2011-01-01
As art department budgets across the country continue to shrink, art teachers are increasingly on the lookout for inexpensive materials that can be used to teach a range of concepts. In this article, the authors describe a newspaper beam tower project inspired by the book, "The Wonderful Towers of Watts" by Patricia Zelver. There are many more…
Extension-matrix representation theory of light beams and Beauregard effect
Li, Chunfang
2007-01-01
A light beam in free space is found to be representable by an integral over a vectorial angular spectrum that is expressed in terms of a two-form angular spectrum and an extension matrix. There exists one freedom to be chosen for the general extension matrix. Two types are considered. In the paraxial approximation, one describes uniformly polarized beams, and the other describes non-uniformly polarized beams, including the axially symmetric polarized beam as a special case. It is shown that the non-uniformly polarized beams bear the Beauregard effect that was speculated more than 40 years ago.
Methods for obtaining a uniform volume concentration of implanted ions
International Nuclear Information System (INIS)
Three simple practical methods of irradiations with high energy particles providing the conditions for obtaining a uniform volume concentration of the implanted ions in the massive samples are described in the present paper. Realization of the condition of two-sided irradiation of a plane sample during its rotation in the flux of the projectiles is the basis of the first method. The use of free air as a filter with varying absorbent ability due to movement of the irradiated sample along ion beam brought to the atmosphere is at the basis of the second method of uniform ion alloying. The third method for obtaining a uniform volume concentration of the implanted ions in a massive sample consists of irradiation of a sample through the absorbent filter in the shape of a foil curved according to the parabolic law moving along its surface. The first method is the most effective for obtaining a great number of the samples, for example, for mechanical tests, the second one - for irradiation in different gaseous media, and the third one - for obtaining high concentrations of the implanted ions under controlled (regulated) thermal and deformation conditions. 2 refs., 7 figs
Infrared imaging diagnostics for INTF ion beam
Sudhir, D.; Bandyopadhyay, M.; Pandey, R.; Joshi, J.; Yadav, A.; Rotti, C.; Bhuyan, M.; Bansal, G.; Soni, J.; Tyagi, H.; Pandya, K.; Chakraborty, A.
2015-04-01
In India, testing facility named INTF [1] (Indian test facility) is being built in Institute for Plasma Research to characterize ITER-Diagnostic Neutral Beam (DNB). INTF is expected to deliver 60A negative hydrogen ion beam current of energy 100keV. The beam will be operated with 5Hz modulation having 3s ON/20s OFF duty cycle. To characterize the beam parameters several diagnostics are at different stages of design and development. One of them will be a beam dump, made of carbon fiber composite (CFC) plates placed perpendicular to the beam direction at a distance lm approximately. The beam dump needs to handle ˜ 6MW of beam power with peak power density ˜ 38.5MW/m2. The diagnostic is based on thermal (infra-red - IR) imaging of the footprint of the 1280 beamlets falling on the beam dump using four IR cameras from the rear side of the dump. The beam dump will be able to measure beam uniformity, beamlet divergence. It may give information on relative variation of negative ion stripping losses for different beam pulses. The design of this CFC based beam dump needs to address several physics and engineering issues, including some specific inputs from manufacturers. The manuscript will describe an overview of the diagnostic system and its design methodology highlighting those issues and the present status of its development.
Underdense plasma lenses for focusing particle beams
International Nuclear Information System (INIS)
Plasma lenses are of interest for providing ultra-strong focusing of particle beams in order to enhance the luminosity of a high-energy linear collider. Previous work has explored the selfpinch of e+ or e- beams as they pass through an overdense slab of passive plasma (i.e., plasma density much greater than the beam density). Here the authors examine the focusing of beams in an underdense plasma through physical and particle simulation models. In this regime the plasma dynamics becomes highly non-linear and differs for e+ and e- beams. For e- beams the plasma electrons are almost completely expelled by the beam's space charge leaving a uniform column of ion charge that provides the focusing force. Compared to the overdense lens, the underdense lens has the advantages that spherical aberrations, longitudinal aberrations, and plasma contribution to background in the detectors are all greatly reduced. 10 refs., 4 figs., 1 tab
Institute of Scientific and Technical Information of China (English)
胡俊亮; 颜全胜; 郑恒斌; 崔楠楠; 余晓琳
2014-01-01
A new method for FEM updating based on Kriging model was developed.The Kriging model is a linear unbiased minimum variance estimation to the unknown data in a region according to some characteristic information of region’s samples which have similar features with the unknown data.This method can obtain higher accuracy predicted results based on a small number of samples.Through a planar truss FEMupdating example,the feasibility and accuracy of the Kriging model were verified.And then the Kriging model was applied to a concrete-filled-steel-tubular (CFST)arch/continuous beam bridge FEM updating and the results were compared with those by the method of genetic algorithm (GA) combined with BP neural network.The analysis results show that the Kriging model needs only a certain amount of measured frequency data for FEM updating.There is no iterative calculation like in the FEM,which will exhaust much calculation time in updating program.This method can accurately predict the modal information outside the active frequency range.The results testify the high computational efficiency,accuracy and feasibility of the method applied in actual engineering.%提出基于Kriging模型的有限元模型修正方法。Kriging模型为据区域内若干信息样品某种特征数据对该区域同类特征未知数作线性无偏、最小方差估计方法，其只用少量样本即可获得较高精度预测结果。用Kriging模型对平面桁架进行有限元模型修正，验证该方法的可行性与准确性；对一连续梁拱桥进行模型修正，并与GA算法、BP神经网络方法模型修正结果比较分析。Kriging模型仅需一定量测量频率信息即可完成模型修正，能避免修正过程中进行有限元模型迭代计算。结果表明，该方法能准确预测有效频率范围（active frequency range）外模态信息，计算效率、精度较高，可用于工程实践。
Study on improvement of the laser uniformity transformation of overlapping-image waveguide cavity
Institute of Scientific and Technical Information of China (English)
Zebin Fan; Junchang Li; Chongguang Li; Kun Ma
2005-01-01
@@ After propagating through the overlapping-image integral mirror, the interference fringe is a major factor that affects the uniformity of the image plane. In this paper, a He-Ne laser is used as light source, and the complex amplitude of the incident laser beam is modulated by an alternating electric field controlled vibrating mirror that is placed before the optical system. The experimental results show that after propagating through the overlapping-image integral mirror, not only the contrast of the interference fringes on the image plane is depressed, but also the uniformity of the intensity distribution of the transformed light beam is improved. Finally, based on the experimental results, two optical systems that can be applied to high power laser uniformity transformation are presented.
A School Uniform Program That Works.
Loesch, Paul C.
1995-01-01
According to advocates, school uniforms reduce gang influence, decrease families' clothing expenditures, and help mitigate potentially divisive cultural and economic differences. Aiming to improve school climate, a California elementary school adopted uniforms as a source of pride and affiliation. This article describes the development of the…
School Dress Codes and Uniform Policies.
Anderson, Wendell
2002-01-01
Opinions abound on what students should wear to class. Some see student dress as a safety issue; others see it as a student-rights issue. The issue of dress codes and uniform policies has been tackled in the classroom, the boardroom, and the courtroom. This Policy Report examines the whole fabric of the debate on dress codes and uniform policies…
School Uniform Policies: Students' Views of Effectiveness.
McCarthy, Teresa M.; Moreno, Josephine
2001-01-01
Focus-group interviews of New York City middle-school students about their perceptions of the effectiveness of the school-uniform policy. Finds that students' perceptions of the effects of school-uniform policy on school culture varied considerably with those intended by the principal. (Contains 40 references.) (PKP)
School Uniforms and Discourses on Childhood.
Bodine, Ann
2003-01-01
This ethnographic study examined the introduction of school uniforms in the public schools of one California city. Findings indicated that the uniform issue intersected with issues such as student safety and violence, family stress, egalitarianism, competitive dressing, and a power struggle over shaping the childhood environment. It was concluded…
Radionic Non-uniform Stable Black Strings
Tamaki, Takashi; Kanno, Sugumi; Soda, Jiro
2003-01-01
Non-uniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a non-trivial hair of black strings. The stability of solutions is demonstrated using the catastrophe theory. The black strings are shown to be non-uniform.
A Uniform Syntax and Discourse Structure
DEFF Research Database (Denmark)
Hardt, Daniel
2013-01-01
I present arguments in favor of the Uniformity Hypothesis: the hypothesis that discourse can extend syntax dependencies without conflicting with them. I consider arguments that Uniformity is violated in certain cases involving quotation, and I argue that the cases presented in the literature...
Deposition uniformity inspection in IC wafer surface
Li, W. C.; Lin, Y. T.; Jeng, J. J.; Chang, C. L.
2014-03-01
This paper focuses on the task of automatic visual inspection of color uniformity on the surface of integrated circuits (IC) wafers arising from the layering process. The oxide thickness uniformity within a given wafer with a desired target thickness is of great importance for modern semiconductor circuits with small oxide thickness. The non-uniform chemical vapor deposition (CVD) on a wafer surface will proceed to fail testing in Wafer Acceptance Test (WAT). Early detection of non-uniform deposition in a wafer surface can reduce material waste and improve production yields. The fastest and most low-priced inspection method is a machine vision-based inspection system. In this paper, the proposed visual inspection system is based on the color representations which were reflected from wafer surface. The regions of non-uniform deposition present different colors from the uniform background in a wafer surface. The proposed inspection technique first learns the color data via color space transformation from uniform deposition of normal wafer surfaces. The individual small region statistical comparison scheme then proceeds to the testing wafers. Experimental results show that the proposed method can effectively detect the non-uniform deposition regions on the wafer surface. The inspection time of the deposited wafers is quite compatible with the atmospheric pressure CVD time.
Uniformity in a Dual Assessment System
Chicoine, David L.; Giertz, J Fred
1988-01-01
Variation in property tax assessment uniformity is studied using data from a "dual" assessment structure where county assessment authority overlaps township assessing responsibility and elected local assessors work with appointed county assessment officers. Particular attention is given to the impact of the size and organization of assessment jurisdictions on assessment uniformity.
Radionic Non-Uniform Black Strings
Tamaki, T.; Kanno, S.; Soda, J.
Non-uniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a non-trivial hair of black strings. The stability of solutions is demonstrated using the catastrophe theory. The black strings are shown to be non-uniform.
Continuation of tailored composite structures of ordered staple thermoplastic material
Santare, Michael H.; Pipes, R. Byron
1992-01-01
The search for the cost effective composite structure has motivated the investigation of several approaches to develop composite structure from innovative material forms. Among the promising approaches is the conversion of a planar sheet to components of complex curvature through sheet forming or stretch forming. In both cases, the potential for material stretch in the fiber direction appears to offer a clear advantage in formability over continuous fiber systems. A framework was established which allows the simulation of the anisotropic mechanisms of deformation of long discontinuous fiber laminates wherein the matrix phase is a viscous fluid. Predictions for the effective viscosities of a hyper-anisotropic medium consisting of collimated, discontinuous fibers suspended in viscous matrix were extended to capture the characteristics of typical polymers including non-Newtonian behavior and temperature dependence. In addition, the influence of fiber misorientation was also modeled by compliance averaging to determine ensemble properties for a given orientation distribution. A design tool is presented for predicting the effect of material heterogeneity on the performance of curved composite beams such as those used in aircraft fuselage structures. Material heterogeneity can be induced during manufacturing processes such as sheet forming and stretch forming of thermoplastic composites. This heterogeneity can be introduced in the form of fiber realignment and spreading during the manufacturing process causing radial and tangential gradients in material properties. Two analysis procedures are used to solve the beam problems. The first method uses separate two-dimensional elasticity solutions for the stresses in the flange and web sections of the beam. The separate solutions are coupled by requiring that forces and displacements match section boundaries. The second method uses an approximate Rayleigh-Ritz technique to find the solutions for more complex beams. Analyses
Gamp, Alexander
2013-01-01
We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.
A uniform parametrization of moment tensors
Tape, Walter; Tape, Carl
2015-09-01
A moment tensor is a 3 × 3 symmetric matrix that expresses an earthquake source. We construct a parametrization of the 5-D space of all moment tensors of unit norm. The coordinates associated with the parametrization are closely related to moment tensor orientations and source types. The parametrization is uniform, in the sense that equal volumes in the coordinate domain of the parametrization correspond to equal volumes of moment tensors. Uniformly distributed points in the coordinate domain therefore give uniformly distributed moment tensors. A cartesian grid in the coordinate domain can be used to search efficiently over moment tensors. We find that uniformly distributed moment tensors have uniformly distributed orientations (eigenframes), but that their source types (eigenvalue triples) are distributed so as to favour double couples.
Diagnosing light ion beam diodes
International Nuclear Information System (INIS)
This lecture begins with a discussion of diagnostics in ion-beam diodes. This will include electromagnetic measurements, measurements of the electron cloud, and measurements of anode plasmas. A few minutes will be spent on diagnostics of distributed ion sources required for one class of ion diodes, the plasma-filled versions, which require high-density, highly ionized sources of very uniform plasma. The measurements of the beam characteristics will then be discussed. This will be broken into two regions; the region near the diode where diagnostics are generally extensions of those used in other fields; and the region near focus where new diagnostics have been developed
POLYNOMIAL SOLUTIONS TO PIEZOELECTRIC BEAMS(Ⅰ)--SEVERAL EXACT SOLUTIONS
Institute of Scientific and Technical Information of China (English)
DING Hao-jiang; JIANG Ai-min
2005-01-01
For the orthotropic piezoelectric plane problem, a series of piezoelectric beams is solved and the corresponding exact solutions are obtained with the trial-anderror method on the basis of the general solution in the case of three distinct eigenvalues, in which all displacements, electrical potential, stresses and electrical displacements are expressed by three displacement functions in terms of harmonic polynomials. These problems are rectangular beams having rigid body displacements and identical electrical potential, rectangular beams under uniform tension and electric displacement as well as pure shearing and pure bending, beams of two free ends subjected to uniform electrical potential on the upper and lower surfaces.
International Nuclear Information System (INIS)
This presentation deals with the following keypoints: Information Technology (IT) Business Continuity and Recovery essential for any business; lessons learned after Sept. 11 event; Detailed planning, redundancy and testing being the key elements for probability estimation of disasters
... Care Obesity at Midlife May Speed Alzheimer’s Onset Hello from my mom Easing the Behavior Problems of ... Managers Continuing Care FOR MORE ARTICLES CLICK HERE Hello from my mom Common Estate Planning Errors Alzheimer’s ...
Focusing of truncated Gaussian beams
Horváth, Zoltán L.; Bor, Zsolt
2003-07-01
It is shown that the focusing of truncated Gaussian beams can be treated by the same manner as uniform spherical waves, i.e., the diffraction integral can be expressed by the Lommel functions, which offers a very efficient way for the calculation of the three-dimensional light distribution near focus. All the expressions for the uniform spherical waves hold good for Gaussian beams if the first variable in the Lommel functions is extended to the complex domain. The intensity distribution depending on the Fresnel number and the truncation coefficient is calculated. The location of the first few minima and maxima of the intensity in focal plane is given for different values of the truncation coefficient. The phase behavior depending on the truncation coefficient is studied.
Wide-aperture laser beam measurement using transmission diffuser: errors modeling
Matsak, Ivan S.
2015-06-01
Instrumental errors of measurement wide-aperture laser beam diameter were modeled to build measurement setup and justify its metrological characteristics. Modeled setup is based on CCD camera and transmission diffuser. This method is appropriate for precision measurement of large laser beam width from 10 mm up to 1000 mm. It is impossible to measure such beams with other methods based on slit, pinhole, knife edge or direct CCD camera measurement. The method is suitable for continuous and pulsed laser irradiation. However, transmission diffuser method has poor metrological justification required in field of wide aperture beam forming system verification. Considering the fact of non-availability of a standard of wide-aperture flat top beam modelling is preferred way to provide basic reference points for development measurement system. Modelling was conducted in MathCAD. Super-Lorentz distribution with shape parameter 6-12 was used as a model of the beam. Using theoretical evaluations there was found that the key parameters influencing on error are: relative beam size, spatial non-uniformity of the diffuser, lens distortion, physical vignetting, CCD spatial resolution and, effective camera ADC resolution. Errors were modeled for 90% of power beam diameter criteria. 12-order Super-Lorentz distribution was primary model, because it precisely meets experimental distribution at the output of test beam forming system, although other orders were also used. The analytic expressions were obtained analyzing the modelling results for each influencing data. Attainability of <1% error based on choice of parameters of expression was shown. The choice was based on parameters of commercially available components of the setup. The method can provide up to 0.1% error in case of using calibration procedures and multiple measurements.
Asymmetric Laguerre-Gaussian beams
Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.
2016-06-01
We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.
Quantification of perceived macro-uniformity
Lee, Ki-Youn; Bang, Yousun; Choh, Heui-Keun
2011-01-01
Macro-uniformity refers to the subjective impression of overall uniformity in the print sample. By the efforts of INCITS W1.1 team, macro-uniformity is categorized into five types of attributes: banding, streaks, mottle, gradients, and moiré patterns, and the ruler samples are generated with perceptual scales. W1.1 macro-uniformity ruler is useful for judging the levels of print defect, but it is not an easy task to reproduce the samples having the same perceptual scales at different times in different places. An objective quantification method is more helpful and convenient for developers to analyze print quality and design printing system components. In this paper, we propose a method for measuring perceived macro-uniformity for a given print using a flat-bed scanner. First, banding, 2D noise, and gradients are separately measured, and they are converted to the perceptual scales based on subjective results of each attribute. The correlation coefficients between the measured values of the attributes and the perceptual scales are 0.92, 0.97, and 0.86, respectively. Another subjective test is performed to find the relationship between the overall macro-uniformity and the three attributes. The weighting factors are obtained by the experimental result, and the final macro-uniformity grade is determined by the weighted sums of each attribute.
Rumolo, G
2014-01-01
When a beam propagates in an accelerator, it interacts with both the external fields and the self-generated electromagnetic fields. If the latter are strong enough, the interplay between them and a perturbation in the beam distribution function can lead to an enhancement of the initial perturbation, resulting in what we call a beam instability. This unstable motion can be controlled with a feedback system, if available, or it grows, causing beam degradation and loss. Beam instabilities in particle accelerators have been studied and analysed in detail since the late 1950s. The subject owes its relevance to the fact that the onset of instabilities usually determines the performance of an accelerator. Understanding and suppressing the underlying sources and mechanisms is therefore the key to overcoming intensity limitations, thereby pushing forward the performance reach of a machine.
The refined theory of transversely isotropic piezoelectric rectangular beams
Institute of Scientific and Technical Information of China (English)
GAO; Yang; WANG; Minzhong
2006-01-01
The problem of deducing one-dimensional theory from two-dimensional theory for a transversely isotropic piezoelectric rectangular beam is investigated. Based on the piezoelasticity theory, the refined theory of piezoelectric beams is derived by using the general solution of transversely isotropic piezoelasticity and Lur'e method without ad hoc assumptions. Based on the refined theory of piezoelectric beams, the exact equations for the beams without transverse surface loadings are derived, which consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beams under transverse loadings are derived directly from the refined beam theory. As a special case, the governing differential equations for transversely isotropic elastic beams are obtained from the corresponding equations of piezoelectric beams. To illustrate the application of the beam theory developed, a uniformly loaded and simply supported piezoelectric beam is examined.
Whiteness formula in CIELAB uniform color space
Institute of Scientific and Technical Information of China (English)
Guoxin He; Mingxun Zhou
2007-01-01
@@ Many attempts have been made to standardize the calculation of whiteness. Whiteness formulas currently in use satisfactorily characterize the appearance of commercial whiteness. However, they have poor correlations with the observers' evaluations, and are often unsuccessful in assessing tinted white samples.A whiteness formula in the CIELAB uniform color space is developed in this paper. Several whiteness formulas are analyzed and compared. The experimental results show that the whiteness formula in the CIELAB uniform color space agrees well with the visual ranking, and it is superior to the CIE whiteness formula and the others in visual correlativity, uniformity and applicability.
Uniform supersaturated design and its construction
Institute of Scientific and Technical Information of China (English)
FANG; Kaitai(方开泰); GE; Gennian(葛根年); LIU; Minqian(刘民千)
2002-01-01
Supersaturated designs are factorial designs in which the number of main effects is greater than the number of experimental runs. In this paper, a discrete discrepancy is proposed as a measure of uniformity for supersaturated designs, and a lower bound of this discrepancy is obtained asa benchmark of design uniformity. A construction method for uniform supersaturated designs via resolvable balanced incomplete block designs is also presented along with the investigation of properties of the resulting designs. The construction method shows a strong link between these two different kinds of designs.
Forerunning mode transition in a continuous waveguide
Slepyan, Leonid; Mishuris, Gennady
2014-01-01
We have discovered a new, forerunning mode transition as the periodic transition wave propagating in a uniform continuous waveguide. The latter is represented by an elastic beam separating from the elastic foundation under the action of sinusoidal waves. The critical displacement is the separation criterion. We show that the steady-state separation mode, where the separation front speed is independent of the wave amplitude, exists only in a bounded speed-dependent range of the wave amplitude. As the latter exceeds the critical value the steady-state mode is replaced by a more complicated regime with porous-like local separations emerging at a distance ahead of the main transition front. The crucial feature of this simple model is that the wave group speed is greater than the phase speed. The analytical solution allows us to show in detail how the steady-state mode transforms into the forerunning one. The established forerunning mode studied numerically manifests itself as a periodic process. As the incident w...
Nel, Louis
2016-01-01
This book presents a detailed, self-contained theory of continuous mappings. It is mainly addressed to students who have already studied these mappings in the setting of metric spaces, as well as multidimensional differential calculus. The needed background facts about sets, metric spaces and linear algebra are developed in detail, so as to provide a seamless transition between students' previous studies and new material. In view of its many novel features, this book will be of interest also to mature readers who have studied continuous mappings from the subject's classical texts and wish to become acquainted with a new approach. The theory of continuous mappings serves as infrastructure for more specialized mathematical theories like differential equations, integral equations, operator theory, dynamical systems, global analysis, topological groups, topological rings and many more. In light of the centrality of the topic, a book of this kind fits a variety of applications, especially those that contribute to ...
Institute of Scientific and Technical Information of China (English)
阙孜
2013-01-01
In the steel/concrete composite beam calculation, according to the specifications, shear stresses are calculated for solid beam transverse bending, without torsional shear stress. For curved composite beams torques are large, it is necessary to study whether torsional shear stress effect should be taken into account. Considering an engineering example, the free torsional shear stresses are calculated; bending shear stresses are respectively calculated for a closed thin - walled member and a solid beam, and the calculation results were compared and analyzed for the formulation of a reasonable computation method.%论述在钢混组合梁计算中,规范中按实体梁横向弯曲剪应力计算,没有扭转剪应力计算的规定.曲线组合梁的扭矩较大,讨论是否需要考虑扭转剪应力的影响.结合工程实例,计算分析自由扭转剪应力,按闭口薄壁构件和实体梁分别计算弯曲剪应力,并对计算结果进行对比分析,提出合理的计算方法.
Indian Academy of Sciences (India)
S C L Srivastava; S V L S Rao; P Singh
2007-10-01
A code for 2D space-charge dominated beam dynamics study in beam transport lines is developed. The code is used for particle-in-cell (PIC) simulation of -uniform beam in a channel containing solenoids and drift space. It can also simulate a transport line where quadrupoles are used for focusing the beam. Numerical techniques as well as the results of beam dynamics studies are presented in the paper.
Electrode structure for uniform corona discharge
Gange, R. A.; Steinmetz, C. C.
1976-01-01
Single corona-discharge needle is used to apply uniform charge to thermoplastic medium in holograph-storage system. Needle is connected to flat transparent electrode that is parallel to thermoplastic.
Variational Principles in Fang Uniform Spaces
Turinici, Mihai
2010-01-01
The variational principle in Fang uniform spaces due to Hamel [Nonlin. Anal., 62 (2005), 913-924] is deductible from the generalized metric version of Ekeland's [Bull. A.M.S. (N. S.), 1 (1979), 443-474].
Intense electron beam propagation into vacuum
International Nuclear Information System (INIS)
The authors have performed experimental and theoretical studies of the propagation of an intense electron beam (1 MeV, 27 kA, 30 ns) into a long evacuated drift cube. In one case the beam propagates because an applied axial magnetic field immerses the entire system. In the second case a localized source of ions for charge neutralization enables the beam is propagate. In the case of a magnetically confined beam, experimental results for current propagation as a function of uniform applied magnetic field (0-1.2 Tesla) are presented for various drift tube diameters, cathode geometries, and anode aperture sizes. An analytic model of laminar beam flow is presented which predicts the space charge limited current of a solid intense relativistic electron beam (IREB) propagating in a grounded drift tube as a function of tube and diode sizes and applied magnetic field. Comparisons between the experimental and theoretical results are discussed
International Nuclear Information System (INIS)
The philosophy of these tests is to measure the motion of a low current, small diameter electron beam in the accelerator before running high current. By using low current, we can study particle motion in the applied fields without any extra complications associated with the self-forces of high currents. With the steering magnets off, we have measured the transverse drift of the probe beam. Also, we have used the probe beam to optimize the current in the steering magnets to compensate for the drift. There have been concurrent efforts to locate the source of the error field which is presumed to cause the drift. So far, the source has not been established but the search is continuing
Démoré, Christine E. M.; Dahl, Patrick M.; Yang, Zhengyi; Glynne-Jones, Peter; Melzer, Andreas; Cochran, Sandy; MacDonald, Michael P.; Spalding, Gabriel C.
2014-05-01
Negative radiation forces act opposite to the direction of propagation, or net momentum, of a beam but have previously been challenging to definitively demonstrate. We report an experimental acoustic tractor beam generated by an ultrasonic array operating on macroscopic targets (>1 cm) to demonstrate the negative radiation forces and to map out regimes over which they dominate, which we compare to simulations. The result and the geometrically simple configuration show that the effect is due to nonconservative forces, produced by redirection of a momentum flux from the angled sides of a target and not by conservative forces from a potential energy gradient. Use of a simple acoustic setup provides an easily understood illustration of the negative radiation pressure concept for tractor beams and demonstrates continuous attraction towards the source, against a net momentum flux in the system.
Energy Technology Data Exchange (ETDEWEB)
Woof, M.
2002-10-01
This paper looks into both safety and technological developments in continuous mining. Manufacturers covered include Hydraphase, Eimco, Deilmann-Haniel, DBT and Joy. A recent Health and Safety Executive report mentioned three in incidents of frictional ignition of flammable gas by cutting equipment in a five year period to April 1999. 4 photos.
Uniform and Robust Peptoid Microsphere Coatings
Servoss, Shannon L.; Phillip Blake; Melissa L. Hebert; Dhaval S. Shah
2013-01-01
Peptoids that are helical and partially water soluble have been shown to self-assemble into microspheres when the peptoid solution is dried on a silicon substrate. Such microsphere coatings have great potential for use in biosensor technologies, specifically to increase the surface area for binding. However, in order to be useful, the peptoids must consistently form uniform coatings. In this study we investigated the effects of various coating protocol parameters on the uniformity of the resu...
LIMITING BEHAVIOR OF UNIFORM RECURSIVE TREES
Institute of Scientific and Technical Information of China (English)
Su Chun; Feng Qunqiang; Liu Jie
2007-01-01
The authors consider the limiting behavior of various branches in a uniform recursive tree with size growing to infinity. The limiting distribution of ζn,m, the number of branches with size m in a uniform recursive tree of order n, converges weakly to a Poisson distribution with parameter 1/m with convergence of all moments. The size of any large branch tends to infinity almost surely.
Numerical analysis of the direct drive illumination uniformity for the Laser MegaJoule facility
Energy Technology Data Exchange (ETDEWEB)
Temporal, M., E-mail: mauro.temporal@hotmail.com [Centre de Mathématiques et de Leurs Applications, ENS Cachan and CNRS, 61 Av. du President Wilson, F-94235 Cachan Cedex (France); Canaud, B. [CEA, DIF, F-91297 Arpajon Cedex (France); Garbett, W. J. [AWE plc, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Ramis, R. [ETSI Aeronáuticos, Universidad Politécnica de Madrid, 28040 Madrid (Spain)
2014-01-15
The illumination uniformity provided during the initial imprinting phase of the laser foot pulse in a direct drive scenario at the Laser MegaJoule facility has been analyzed. This study analyzes the quality of the illumination of a spherical capsule and concerns the uniformity of the first shock generate in the absorber of an Inertial Confinement Fusion capsule. Four configurations making use of all or some of the 80 laser beams organized in the 20 quads of the cones at 49° and 131° with respect to the polar axis have been considered in order to assemble the foot pulse. Elliptical and circular super-gaussian laser intensity profiles taking into account beam-to-beam power imbalance (10%), pointing error (50 μm), and target positioning (20 μm) have been considered. It has been found that the use of the Polar Direct Drive technique can in some cases reduce the irradiation non-uniformity by a factor as high as 50%. In all cases, elliptical profile provides better results in comparison with the circular one and it is shown that the minimum of the non-uniformity is also a function of the capsule radius.
Institute of Scientific and Technical Information of China (English)
李才平; 曾祥蓉; 王仲刚; 陈进
2014-01-01
In order to study the mechanical properties of the reinforced concrete continuous beam side-bonded with pre-stressed CFRP sheets on the longitudinal direction under the initial load, four two-span continuous beams including one unreinforced beam and three reinforced beams are investigated. Pre-stressed CFRP sheets were side-bonded on the lower part of the reinforced beam on each cross, and CFRP sheets were side-bonded on the upper part of the middle bearing. The test data such as bearing capacity, deformation and cracks were obtained in every loading stage by the static test. At the same time, the nonlinear finite analysis on the test beams was carried out by ABAQUS software, and the results of finite element analysis were compared with the experiment. The test results show that the yield load and the limit load of the continuous beams side-bonded with pre-stressed CFRP sheet on the longitudinal direction can be improved obviously. In addition, the stiffness of the continuous beam side-bonded with pre-stressed CFRP sheets can be increased, but its deformation can be reduced. The higher the pre-stressed level is, the higher the value of yield load is and the smaller value of the deformation is. The results of nonlinear finite element analysis of the test beams based on the software ABAQUS have good agreement with the test results, so it can provide reference for the similar structure design and test.%为研究负载作用下纵向侧贴预应力碳纤维布加固钢筋混凝土连续梁的受力性能,制作了4根2跨连续梁,其中1根未加固,3根加固。在加固梁每跨下部纵向侧贴预应力碳纤维布,中间支座上部纵向侧贴非预应力碳纤维布。通过静载试验,得到了连续梁的受弯承载力、变形、裂缝等试验数据。同时,利用非线性有限元分析软件ABAQUS对试验梁进行数值模拟,并与试验结果比较。结果表明：负载作用下纵向侧贴预应力碳纤维布加固钢筋混凝土连续梁能显
Non-Linear Beam Transport System for the LENS 7 MeV Proton Beam
Jones, William P; Derenchuk, Vladimir Peter; Rinckel, Thomas; Solberg, Keith
2005-01-01
A beam transport system has been designed to carry a high-intensity low-emittance proton beam from the exit of the RFQ-DTL acceleration system of the Indiana University Low Energy Neutron System (LENS)* to the neutron production target. The goal of the design was to provide a beam of uniform density over a 3cm by 3cm area at the target. Two octupole magnets** are employed in the beam line to provide the necessary beam phase space manipulations to achieve this goal. First order calculations were done using TRANSPORT and second order calculations have been performed using TURTLE. Second order simulations have been done using both a Gaussian beam distribution and a particle set generated by calculations of beam transport through the RFQ-DTL using PARMILA. Comparison of the design characteristics with initial measurements from the LENS commissioning process will be made.
1977-01-01
A four-block collimator installed on a control table for positioning the alignment reference marks. Designed for use with SPS secondary beams, the collimator operates under vacuum conditions. See Annual Report 1976 p. 121 and photo 7701014.
Institute of Scientific and Technical Information of China (English)
戴公连; 唐立新; 汪禹
2015-01-01
为了解边中跨比对大跨度铁路连续梁拱组合桥受力特性的影响，对目前大跨度铁路梁拱组合桥的边中跨比进行统计，并以兰渝线某（82＋172＋82）m 连续梁拱组合桥为工程背景，分析边中跨比对该桥内力、变形、支反力、稳定性等方面影响。研究结果表明：大跨度铁路连续梁拱组合桥的合理边中跨比取值为0．46～0．51；边中跨比取值较小时，对结构受力和变形有利，但边支座负反力的出现限制其值应大于0．43；边中跨比的取值对该桥基频和结构稳定性影响较小，随边中跨比由0．447增加到0．506，该桥的稳定安全系数仅增大7．6％。%Span ratio is one of the important design parameters in continuous beam -arch bridge,which directly affects the structural stress reasonably.In order to learn the effects of span ratio on the structural force of railway continuous beam -arch bridge,statistics of span ratio in the current long -span railway beam -arch bridges was analyzed.Taking an (82 +172 +82)m long -span continuous beam -arch bridge on the Lanzhou -Chongqing railway as an example,the effects of span ratio on its internal force,displacement,support reaction,stability and so on were analyzed.The analysis results show that the span ratio of long -span railway continuous beam -arch bridge varies from 0.46 to 0.51.Small span ratio is in favor of structural stress and deformation,but the e-mergence of negative support reaction limits its value should be greater than 0.43.While the contribution of span ratio to natural frequency and structural stability is small.Moreover,it is found that the value of stability factors only increased 7.6% with the span ratio increasing from 0.447 to 0.506.
Low voltage, hermetically sealed electron beam accelerator for industrial applications
International Nuclear Information System (INIS)
Three types of hermetically sealed, low voltage electron beam accelerators and novel solid state power supply/control systems have been developed by Advanced Electron Beams. These accelerators produce uniform, unscanned electron beams through the unique management of the thermionic emitter profile and vacuum body shape. The power density of the accelerators range from 0.02 to 0.2 kW per square centimetre with accelerating voltages ranging from 60 to 150 kV and extracted electron currents of 1 to 30 mA. A wide variety of in-process-line industrial applications have been implemented and continue to be developed for these accelerators including: curing of high density and/or high opacity thin films; cross-linking or chain scission of thermoplastic films; pre-fill disinfestation of food and beverage packaging; sterilization of medical devices and pharmaceutical container surfaces; and the active treatment of air streams for pollution abatement and bioburden remediation. This paper will describe the design of the three emitters and the methods of application implementation. (author)
Directory of Open Access Journals (Sweden)
Bram Geron
2013-09-01
Full Text Available Programs with control are usually modeled using lambda calculus extended with control operators. Instead of modifying lambda calculus, we consider a different model of computation. We introduce continuation calculus, or CC, a deterministic model of computation that is evaluated using only head reduction, and argue that it is suitable for modeling programs with control. It is demonstrated how to define programs, specify them, and prove them correct. This is shown in detail by presenting in CC a list multiplication program that prematurely returns when it encounters a zero. The correctness proof includes termination of the program. In continuation calculus we can model both call-by-name and call-by-value. In addition, call-by-name functions can be applied to call-by-value results, and conversely.
Uniform Irradiation Systems Using a Rotatable Stage for Test Facilities of PEFP
Park, Bum-Sik; Kim, Kye-Ryung; Lee Seok Ki
2005-01-01
A new irradiation facility has been developed using not only electric magnets but also a rotatable stage. Generally, the scanning method using magnet has been widely used in most of facilities. However, in this study another new methods have been developed: Three scanning method using rotatable stage have been proved to make uniform irradiation-as large as 20 cm in diameter with more than 90% uniformity. The mechanical wobbler system makes the same effect as the wobbler system. And the beam is swept along the spiral path with a fixed and variable angular frequency during the scanning in two spiral scanning systems, respectively.
Array illumination with minimal non-uniformity based on generalized phase contrast
DEFF Research Database (Denmark)
Palima, Darwin; Glückstad, Jesper
2009-01-01
The generalized phase contrast method (GPC) has been previously shown to be an efficient technique for generating array illumination and is thus highly suitable for such applications as dynamic multiple beam trapping and optical micromanipulation. However, projected arrays usually exhibit intensity...... output spots to improve uniformity. This is combined with matching corrections to the phase shift introduced by the phase contrast filter. Results from numerical experiments show that the array illumination uniformity error improves from over 40% to less than 1% while maintaining the efficiency prior...
First and Second Sound Modes in a Uniform Fermi Gas
Institute of Scientific and Technical Information of China (English)
HUANG Bei-Bing; WAN Shao-Long
2009-01-01
First and second sound modes in a uniform fermionic atom gas with Feshbach resonance are investigated in the frame of a two-fluid model at finite temperature. All thermodynamic quantities are calculated for a given thermodynamic potential The analytical results for thermodynamic quantities and sound velocities in BCS and BEC limits are obtained. The numerical rcsults show that there exists a continuous interpolation for sound velocities of the first and second sound modes at fixed T/Tc between BCS and BEC limits. The existence of the second sound mode indicates the existence of superfluidity.
Stability Analysis of Nonuniform Rectangular Beams Using Homotopy Perturbation Method
Directory of Open Access Journals (Sweden)
Seval Pinarbasi
2012-01-01
Full Text Available The design of slender beams, that is, beams with large laterally unsupported lengths, is commonly controlled by stability limit states. Beam buckling, also called “lateral torsional buckling,” is different from column buckling in that a beam not only displaces laterally but also twists about its axis during buckling. The coupling between twist and lateral displacement makes stability analysis of beams more complex than that of columns. For this reason, most of the analytical studies in the literature on beam stability are concentrated on simple cases: uniform beams with ideal boundary conditions and simple loadings. This paper shows that complex beam stability problems, such as lateral torsional buckling of rectangular beams with variable cross-sections, can successfully be solved using homotopy perturbation method (HPM.
Controlled uniform coating from the interplay of Marangoni flows and surface-adsorbed macromolecules
Kim, Hyoungsoo; Um, Eujin; Jacobi, Ian; Button, Ernie; Stone, Howard A
2016-01-01
Surface coatings and patterning technologies are essential for various physicochemical applications. In this Letter, we describe key parameters to achieve uniform particle coatings in binary solutions: First, multiple sequential Marangoni flows, set by solute and surfactant simultaneously, prevent non-uniform particle distributions and continuously mix suspended materials during droplet evaporation. Second, we show the importance of particle-surface interactions that can be established by surface-adsorbed macromolecules. To achieve a uniform deposit in a binary mixture a small concentration of surfactant and surface-adsorbed polymer (0.05 wt% each) is sufficient, which offers a new physicochemical avenue for control of coatings.
Institute of Scientific and Technical Information of China (English)
韩博; 吴亚平
2011-01-01
In this paper, four-degree parabola of cubic term is adopted to simulate axial displacement of box beam flange, considering vertical shear deformation and shear lag effect, differential equations of symmetrically laminated composite box beam under symmetrical bending have been deduced firstly, and displacement differenee functions in two-equal-span continuous beam under concentrated load P applied at mid-span respectively have been also deduced. Finally, based on a concrete example of composite thin walled box continuous beam,comparing the theoretical results of this paper with the result of the ANSYS finite element simulation and experiment results, it is demonstrated clearly that this method agrees well with the ANSYS finite element and experiment, so the results are reliableand accurate.%以含三次项的四次抛物线作为箱梁翼缘板的纵向位移函数,推导出了考虑横向剪切变形及剪力滞后效应时的双轴对称铺设的复合材料层合箱梁在对称弯曲条件下的控制微分方程,并推导出了两等跨连续梁分别在跨中受一集中力P的位移差函数,最后结合具体的复合材料箱型连续梁实例,将本文理论推导的结果与ANSYS结果以及实验结果进行了对比,结果表明,理论推导的结果与ANSYS结果和实验结果吻合较好,其结果是正确可靠的.
Beam expander telescope design utilizing fast spherical primaries.
Southwell, W H
1979-04-15
An exact geometrical ray analysis has been used to derive the profiles for telescope secondaries that perfectly recollimate beams incident on fast concave spherical mirrors. Both Cassegrainian and Gregorian configurations are possible. The high magnification designs tend to redistribute the energy profile and may be used, for example, to make Gaussian beams more uniform. PMID:20208915
A uniform parameterization of moment tensors
Tape, C.; Tape, W.
2015-12-01
A moment tensor is a 3 x 3 symmetric matrix that expresses an earthquake source. We construct a parameterization of the five-dimensional space of all moment tensors of unit norm. The coordinates associated with the parameterization are closely related to moment tensor orientations and source types. The parameterization is uniform, in the sense that equal volumes in the coordinate domain of the parameterization correspond to equal volumes of moment tensors. Uniformly distributed points in the coordinate domain therefore give uniformly distributed moment tensors. A cartesian grid in the coordinate domain can be used to search efficiently over moment tensors. We find that uniformly distributed moment tensors have uniformly distributed orientations (eigenframes), but that their source types (eigenvalue triples) are distributed so as to favor double couples. An appropriate choice of a priori moment tensor probability is a prerequisite for parameter estimation. As a seemingly sensible choice, we consider the homogeneous probability, in which equal volumes of moment tensors are equally likely. We believe that it will lead to improved characterization of source processes.
Nurses' uniform: an investigation of mobility.
Stubbs, D A; Buckle, P W; Hudson, M P; Butler, P E; Rivers, P M
1985-01-01
An investigation of the mobility of nurses under three clothing conditions is reported. The need for such a study has arisen as a result of the concern over a possible mismatch between mobility and patient handling requirements. Thirty-seven nurses participated under two of the clothing conditions ('National' dress uniform, Trouser/tunic combination). In addition, ten of these nurses volunteered to provide control data by being measured in a leotard or a swimming costume. Eleven static and sixteen dynamic anthropometric measures were considered. Each nurse was asked to complete a short questionnaire, relating to her subjective attitudes to the uniform and to her own physical state at the time of measurement. Whilst both uniforms imposed restrictions on the shoulder girdle and trunk of up to 10%, the area of greatest concern was the mobility of the hip joint. Hip flexion was reduced by 26% in the dress uniform. The implications of these findings for patient handling procedures are discussed, as are those of the relationship between the environment and the material. Uniform and the nursing image is also considered.
Energy Technology Data Exchange (ETDEWEB)
Ishii, Yasuyuki; Isoya, Akira; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Tanaka, Ryuichi [Ion Beam Irradiation Service Limited Company, Takasaki, Gunma (Japan)
2001-02-01
This is a short summary on the test fabrication and performance testing. Here micro-beams are understood as beams in diameter smaller than 0.01 {mu} m. We had made a choice of the combination, of the focusing action with a single hole lens, and of the focusing and acceleration actions with a uniform electrostatic field between the electrodes. Measurements has been repeated of the beam radius with a moving knifedge. The spatial resolution now reaches 0.05 {mu} m. (M. Tanaka)
Uniform dimension results for Gaussian random fields
Institute of Scientific and Technical Information of China (English)
WU DongSheng; XIAO YiMin
2009-01-01
Let X = {X(t), t ∈ RN} be a Gaussian random field with values in Rd defined by x(t) = (x1(t),…,xd(t)), At∈RN.(1)The properties of space and time anisotropy of X and their connections to uniform Hausdorff dimension results are discussed. It is shown that in general the uniform Hausdorff dimension result does not hold for the image sets of a space-anisotropic Gaussian random field X. When X is an (N, d)-Gaussian random field as in (1), where X1,..., Xd are independent copies of a real valued, centered Gaussian random field Xo which is anisotropic in the time variable. We establish uniform Hausdorff dimension results for the image sets of X. These results extend the corresponding results on one-dimensional Brownian motion, fractional Brownian motion and the Brownian sheet.
Ultrasonic transducer design for uniform insonation
International Nuclear Information System (INIS)
Techniques used in transducer development for acoustical imaging have been evaluated for the purpose of producing broad, uniform ultrasonic fields from planar radiators. Such fields should be useful in hyperthermia, physical therapy, and ultrasonic bioeffects studies. Fourier inversion of the circ function yielded a source velocity distribution proportional to (P/r) exp ((-ik/2Z) (2Z/sup 2/+r/sup 2/)) J/sub 1/(krP/Z), where r is the radial source coordinate, k is the wave number, and P is the desired radius of uniform insonation at a depth Z in water. This source distribution can be truncated without significantly degrading the solution. A simpler solution consists of exponentially shading the edge of an otherwise uniformly excited disk transducer. This approach was successfully approximated experimentally
DEFF Research Database (Denmark)
Kohlenbach, Ulrich
2002-01-01
The so-called weak Konig's lemma WKL asserts the existence of an infinite path b in any infinite binary tree (given by a representing function f). Based on this principle one can formulate subsystems of higher-order arithmetic which allow to carry out very substantial parts of classical mathematics...... but are 20-conservative over primitive recursive arithmetic PRA (and even weaker fragments of arithmetic). In Kohlenbach [10] (J. Symbolic Logic 57 (1992) 1239-1273) we established such conservation results relative to finite type extensions PRA of PRA (together with a quantifier-free axiom of choice schema...... which-relative to PRA -implies the schema of 10-induction). In this setting one can consider also a uniform version UWKL of WKL which asserts the existence of a functional which selects uniformly in a given infinite binary tree f an infinite path f of that tree. This uniform version of WKL...
Uniform and Robust Peptoid Microsphere Coatings
Directory of Open Access Journals (Sweden)
Shannon L. Servoss
2013-06-01
Full Text Available Peptoids that are helical and partially water soluble have been shown to self-assemble into microspheres when the peptoid solution is dried on a silicon substrate. Such microsphere coatings have great potential for use in biosensor technologies, specifically to increase the surface area for binding. However, in order to be useful, the peptoids must consistently form uniform coatings. In this study we investigated the effects of various coating protocol parameters on the uniformity of the resulting peptoid microsphere coatings, including (i solvent, (ii administration technique, and (iii drying environment. In addition, we investigated the robustness of the coatings as well as the potential for using a glass substrate. These studies show that uniform, robust peptoid microsphere coatings can be formed using protic solvents, a full coverage administration technique, and drying in open air on silicon or glass substrates.
Uniform dimension results for Gaussian random fields
Institute of Scientific and Technical Information of China (English)
2009-01-01
Let X = {X(t),t ∈ RN} be a Gaussian random field with values in Rd defined by X(t) =(X1(t),...,Xd(t)), t ∈ RN.(1) The properties of space and time anisotropy of X and their connections to uniform Hausdorff dimension results are discussed.It is shown that in general the uniform Hausdorff dimension result does not hold for the image sets of a space-anisotropic Gaussian random field X.When X is an(N,d)-Gaussian random field as in(1),where X1,...,Xd are independent copies of a real valued,centered Gaussian random field X0 which is anisotropic in the time variable.We establish uniform Hausdorff dimension results for the image sets of X.These results extend the corresponding results on one-dimensional Brownian motion,fractional Brownian motion and the Brownian sheet.
Annular beam with segmented phase gradients
Directory of Open Access Journals (Sweden)
Shubo Cheng
2016-08-01
Full Text Available An annular beam with a single uniform-intensity ring and multiple segments of phase gradients is proposed in this paper. Different from the conventional superposed vortices, such as the modulated optical vortices and the collinear superposition of multiple orbital angular momentum modes, the designed annular beam has a doughnut intensity distribution whose radius is independent of the phase distribution of the beam in the imaging plane. The phase distribution along the circumference of the doughnut beam can be segmented with different phase gradients. Similar to a vortex beam, the annular beam can also exert torques and rotate a trapped particle owing to the orbital angular momentum of the beam. As the beam possesses different phase gradients, the rotation velocity of the trapped particle can be varied along the circumference. The simulation and experimental results show that an annular beam with three segments of different phase gradients can rotate particles with controlled velocities. The beam has potential applications in optical trapping and optical information processing.
Self-Excited Energy Harvesting in Uniform Fluid Flows Using Piezoelectric Generators
Akaydin, Dogus; Elvin, Niell; Andreopoulos, Yiannis
2010-11-01
A novel energy harvesting configuration consisting of a circular cylinder attached to a piezoelectric beam is investigated experimentally in this study. The cylinder is attached to the free end of a cantilever beam and undergoes bending deformation due to vortex shedding under uniform fluid flow. The periodic change of strain along the piezoelectric beam generates an alternating voltage that can be used to power an electrical circuit such as a wireless sensor. Two major governing parameters were studied: First, the ratio of the length of the cylinder to its diameter and second, the ratio of the length of the beam to the diameter of the cylinder. Both parameters alter the forcing frequency and magnitude of the flow, natural frequency of the structure and ultimately determine the magnitude of the resultant vibrations. The configuration is different from those previously studies since it is a combination of an oscillating cylinder with a flexible splitter plate and the vibrations are induced within a steady, uniform flow. Three dimensionality of the flow complicates its structure and nonlinear oscillations and lock-in phenomena were observed in experiments with beams of low stiffness. It was also observed that aerodynamic interference with several components of the harvester can significantly alter the harvested power.
Temporal, M.; Canaud, B.; Laffite, S.; Le Garrec, B. J.; Murakami, M.
2010-11-01
In the Inertial Confinement Fusion the uniformity of the irradiation still represents a crucial issue. In this context a spherical capsule directly driven by laser beams have been assessed numerically [1]. Two schemes characterized by 32 and 48 directions of irradiation [2] with associated a single laser beam or a bundle of laser beams [3] characterized by a super-Gaussian intensity profile are considered. Beam imperfections as power imbalance and pointing errors have been taken into account. It is found that the focal spot that minimizes the rms deviation depends on the beam imperfections [4]. The numerical calculations show that the uniformity of the irradiation evolves in time. The results calculated considering the illumination of a spherical target will be compared with those obtained when the irradiation is taken into account. [1] M. Temporal, B. Canaud. Eur. Phys. J. D 55 139 (2009). [2] M. Murakami, N. Sarukura, H. Azechi, M. Temporal, A.J. Schmitt, in press to Phys. Plasmas (July issue, 2010). [3] M. Temporal, B. Canaud, B. J. Le Garrec, Phys. Plasmas 17 022701 (2010). [4] M. Temporal, B. Canaud, S. Laffite, B.J. Le Garrec, M. Murakami. Phys. Plasmas 17 064504 (2010).
Formalizing Implementation Strategies for First-Class Continuations
DEFF Research Database (Denmark)
Danvy, Olivier
2000-01-01
-class continuations and that second-class continuations are stackable. A large body of work exists on implementing continuations, but it is predominantly empirical and implementation-oriented. In contrast, our formalization abstracts the essence of first-class continuations and provides a uniform setting...
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false System technical integration requiring uniform... COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1608 System technical integration requiring uniform election of must-carry or...
32 CFR 728.54 - U.S. Public Health Service (USPHS), other than members of the uniformed services.
2010-07-01
... members of the uniformed services. 728.54 Section 728.54 National Defense Department of Defense (Continued... members of the uniformed services. (a) Potential beneficiaries. The following may be beneficiaries of the... superior officer, or the patient if neither of the above is available. When emergency care is...
Hough Transform Based Corner Detection for Laser Beam Positioning
International Nuclear Information System (INIS)
In laser beam alignment in addition to detecting position, one must also determine the rotation of the beam. This is essential when a commissioning new laser beam for National Ignition Facility located at the Lawrence Livermore National Laboratory. When the beam is square, the positions of the corners with respect to one another provides an estimate of the rotation of the beam. This work demonstrates corner detection in the presence or absence of a second order non-uniform illumination caused by a spatial mask. The Hough transform coupled with illumination dependent pre-processing is used to determine the corner points. We show examples from simulated and real NIF images
Hough Transform Based Corner Detection for Laser Beam Positioning
Energy Technology Data Exchange (ETDEWEB)
Awwal, A S
2005-07-26
In laser beam alignment in addition to detecting position, one must also determine the rotation of the beam. This is essential when a commissioning new laser beam for National Ignition Facility located at the Lawrence Livermore National Laboratory. When the beam is square, the positions of the corners with respect to one another provides an estimate of the rotation of the beam. This work demonstrates corner detection in the presence or absence of a second order non-uniform illumination caused by a spatial mask. The Hough transform coupled with illumination dependent pre-processing is used to determine the corner points. We show examples from simulated and real NIF images.
Controlling beam halo-chaos via backstepping design
Institute of Scientific and Technical Information of China (English)
Gao Yuan; Kong Feng
2008-01-01
A backstepping control method is proposed for controlling beam halo-chaos in the periodic focusing channels PFCs) of high-current ion accelerator. The analysis and numerical results show that the method, via adjusting an exterior magnetic field, is effective to control beam halo chaos with five types of initial distribution ion beams, all statistical quantities of the beam halo-chaos are largely reduced, and the uniformity of ion beam is improved. This control method has an important value of application, for the exterior magnetic field can be easily adjusted in the periodical magnetic focusing channels in experiment.
Uniform wire segmentation algorithm of distributed interconnects
Institute of Scientific and Technical Information of China (English)
Yin Guoli; Lin Zhenghui
2007-01-01
A uniform wire segmentation algorithm for performance optimization of distributed RLC interconnects was proposed in this paper. The optimal wire length for identical segments and buffer size for buffer insertion are obtained through computation and derivation, based on a 2-pole approximation model of distributed RLC interconnect. For typical inductance value and long wires under 180nm technology, experiments show that the uniform wire segmentation technique proposed in the paper can reduce delay by about 27% ～ 56% , while requires 34%～69% less total buffer usage and thus 29% to 58% less power consumption. It is suitable for long RLC interconnect performance optimization.
Uniform color space is not homogeneous
Kuehni, Rolf G.
2002-06-01
Historical data of chroma scaling and hue scaling are compared and evidence is shown that we do not have a reliable basis in either case. Several data sets indicate explicitly or implicitly that the number of constant sized hue differences between unique hues as well as in the quadrants of the a*, b* diagram differs making what is commonly regarded as uniform color space inhomogeneous. This problem is also shown to affect the OSA-UCS space. A Euclidean uniform psychological or psychophysical color space appears to be impossible.
von Hellermann, M. G.; Delabie, E.; Jaspers, R. J. E.; Biel, W.; Marchuk, O.; Summers, H. P.; Whiteford, A.; Giroud, C.; Hawkes, N. C.; Zastrow, K. D.
2008-03-01
Charge eXchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package CHEAP", and finally "Forward Prediction of Spectral Features" are described. Beam Emission Spectroscopy (BES) is proposed as indispensable cross-calibration tool for absolute local impurity density measurements and also for the continuous monitoring of the neutral beam power deposition profile. Finally, a full exploitation of the `Motional Stark Effect' pattern is proposed to deduce local pitch angles, total magnetic fields and possibly radial electric fields. For the proposed active beam spectroscopy diagnostic on ITER comprehensive performance studies have been carried out. Estimates of expected spectral signal-to-noise ratios are based on atomic modelling of neutral beam stopping and emissivities for CXRS, BES and background continuum radiation as well as extrapolations from present CXRS diagnostic systems on JET, Tore Supra, TEXTOR and ASDEX-UG. Supplementary to thermal features a further promising application of CXRS has been proposed recently for ITER, that is a study of slowing-down alpha particles in the energy range up to 2 MeV making use of the 100 keV/amu DNB (Diagnostic Neutral Beam) and the 500 keV/amu HNB (Heating Neutral Beam). Synthetic Fast Ion Slowing-Down spectra are evaluated in terms of source rates and slowing-down parameters
An Introduction to the Methodology of Earthquake Resistant Structures of Uniform Response
Grigorian, Carl E.; Mark Grigorian
2012-01-01
Structures of Uniform Response are special earthquake resistant frames in which members of similar groups such as beams, columns and braces of similar nature share the same demand-capacity ratios regardless of their location within the group. The fundamental idea behind this presentation is that seismic structural response is largely a function of design and construction, rather than analysis. Both strength and stiffness are induced rather than investigated. Failure mechanisms and stability c...
Uniform Or Free Dress Code in Schools
Erkan, Doç. Dr. Serdar
2003-01-01
This article attempts to synthesize opinions, results of experiments and research about school dress code policies. Synthesis suggests that there are positive as well as negative effects and consequences of mandatory school uniform policy. Pilot projects should be implemented and social and cultural effects should be examined prior to any decision regarding changes in current dress codes and policies.
School Uniforms in Urban Public High Schools
Draa, Virginia Ann Bendel
2005-01-01
The purpose of this study was to determine whether or not the implementation of a mandatory uniform policy in urban public high schools improved school performance measures at the building level for rates of attendance, graduation, academic proficiency, and student conduct as measured by rates of suspensions and expulsions. Sixty-four secondary…
UNIFORM QUASINILPOTENCY: DEFINITIONS, CONDITIONS, EXAMPLES OF APPLICATIONS
Sumin, Vladimir
2010-01-01
Definition of uniform quasinilpotent family of the operators and definition of superuniform quasinilpotent family of the operators are introduced. Corresponding conditions for functional operators are formulated. Applications of these definititions and conditions in the theory of controllable Volterra functional-operator equations are discussed. Financial support of Russian Fundamental Researches Fund (project 07-01-00495), analytical aimed departmental program "Development of Scientific Pote...
School Uniform Revisited: Procedure, Pressure and Equality
Carney, Damian; Sinclair, Adele
2006-01-01
The House of Lords' decision in "R. (on the application of Begum) v. The Headteacher and Governors of Denbigh High School" considered whether a particular school uniform policy infringed a student's right to manifest her religion under Article 9. This paper analyses the content of this decision, and explores how schools should approach the issue…
Product of n independent uniform random variables
Dettmann, Carl P.; Georgiou, Orestis
2009-01-01
Abstract We give an alternative proof of a useful formula for calculating the probability density function of the product of n uniform, independently and identically distributed random variables. Ishihara (2002, in Japanese) proves the result by induction; here we use Fourier analysis and contour integral methods which provide a more intuitive explanation of how the convolution theorem acts in this case. correspondance: Corresponding author. ...
Mandatory School Uniforms and Freedom of Expression
Vopat, Mark C.
2010-01-01
On 10 December 2007 the Akron City School Board--following the precedent set by many school systems across the United States and the world--instituted a policy of mandatory school uniforms for all students in grades K-8. The measure was met with mixed reviews. While many parents supported the measure, a small group of parents from a selective,…
Uniform infinite and Gibbs causal triangulations
Zohren, Stefan
2012-01-01
We discuss uniform infinite causal triangulations (UICT) and Gibbs causal triangulations which are probabilistic models for the causal dynamical triangulations (CDT) approach to quantum gravity. Since there is a bijection between causal triangulations and planar rooted trees we first discuss some as
Dynamic Uniform Scaling for Multiobjective Genetic Algorithms
DEFF Research Database (Denmark)
Pedersen, Gerulf; Goldberg, David E.
2004-01-01
Before Multiobjective Evolutionary Algorithms (MOEAs) can be used as a widespread tool for solving arbitrary real world problems there are some salient issues which require further investigation. One of these issues is how a uniform distribution of solutions along the Pareto non-dominated front c...
Uniforms: Are They a Good Fit?
Boutelle, Marsha
2008-01-01
In an era where some parents seem unwilling or unable to draw the "clothes" line with their children, where pop culture influences kids' clothing choices as never before, and school safety--including gang violence--is at the top of everyone's minds, school uniforms and dress codes can play a significant role. What that role should be, however, is…
MODERATOR ELEMENTS FOR UNIFORM POWER NUCLEAR REACTOR
Balent, R.
1963-03-12
This patent describes a method of obtaining a flatter flux and more uniform power generation across the core of a nuclear reactor. The method comprises using moderator elements having differing moderating strength. The elements have an increasing amount of the better moderating material as a function of radial and/or axial distance from the reactor core center. (AEC)
UMAPRM: Uniformly sampling the medial axis
Yeh, Hsin-Yi Cindy
2014-05-01
© 2014 IEEE. Maintaining clearance, or distance from obstacles, is a vital component of successful motion planning algorithms. Maintaining high clearance often creates safer paths for robots. Contemporary sampling-based planning algorithms That utilize The medial axis, or The set of all points equidistant To Two or more obstacles, produce higher clearance paths. However, They are biased heavily Toward certain portions of The medial axis, sometimes ignoring parts critical To planning, e.g., specific Types of narrow passages. We introduce Uniform Medial Axis Probabilistic RoadMap (UMAPRM), a novel planning variant That generates samples uniformly on The medial axis of The free portion of C
Suppression of Space Charge Induced Beam Halo in Nonlinear Focusing Channel
Batygin, Yuri K; Kurennoy, Sergey; Li, Chao
2016-01-01
An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. A new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry is discussed. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.
Suppression of space charge induced beam halo in nonlinear focusing channel
Batygin, Yuri K.; Scheinker, Alexander; Kurennoy, Sergey; Li, Chao
2016-04-01
An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. A new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry is discussed. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.
Specialty flat-top beam delivery fibers with controlled beam parameter product
Jollivet, C.; Farley, K.; Conroy, M.; Abramczyk, J.; Belke, S.; Becker, F.; Tankala, K.
2016-03-01
Beam delivery fibers have been used widely for transporting the optical beams from the laser to the subject of irradiation in a variety of markets including industrial, medical and defense applications. Standard beam delivery fibers range from 50 to 1500 μm core diameter and are used to guide CW or pulsed laser light, generated by solid state, fiber or diode lasers. Here, we introduce a novel fiber technology capable of simultaneously controlling the beam profile and the angular divergence of single-mode (SM) and multi-mode (MM) beams using a single-optical fiber. Results of beam transformation from a SM to a MM beam with flat-top intensity profile are presented in the case of a controlled BPP at 3.8 mm*mrad. The scaling capabilities of this flat-top fiber design to achieve a range of BPP values while ensuring a flat-top beam profile are discussed. In addition, we demonstrate, for the first time to the best of our knowledge, the homogenizer capabilities of this novel technology, able to transform random MM beams into uniform flat-top beam profiles with very limited impact on the beam brightness. This study is concluded with a discussion on the scalability of this fiber technology to fit from 50 up to 1500 μm core fibers and its potential for a broader range of applications.
Perceptual uniformity of commonly used color spaces
Avanaki, Ali; Espig, Kathryn; Kimpe, Tom; Xthona, Albert; Marchessoux, Cedric; Rostang, Johan; Piepers, Bastian
2014-03-01
Use of color images in medical imaging has increased significantly the last few years. Color information is essential for applications such as ophthalmology, dermatology and clinical photography. Use of color at least brings benefits for other applications such as endoscopy, laparoscopy and digital pathology. Remarkably, as of today, there is no agreed standard on how color information needs to be visualized for medical applications. This lack of standardization results in large variability of how color images are visualized and it makes quality assurance a challenge. For this reason FDA and ICC recently organized a joint summit on color in medical imaging (CMI). At this summit, one of the suggestions was that modalities such as digital pathology could benefit from using a perceptually uniform color space (T. Kimpe, "Color Behavior of Medical Displays," CMI presentation, May 2013). Perceptually uniform spaces have already been used for many years in the radiology community where the DICOM GSDF standard provides linearity in luminance but not in color behavior. In this paper we quantify perceptual uniformity, using CIE's ΔE2000 as a color distance metric, of several color spaces that are typically used for medical applications. We applied our method to theoretical color spaces Gamma 1.8, 2.0, & 2.2, standard sRGB, and DICOM (correction LUT for gray applied to all primaries). In addition, we also measured color spaces (i.e., native behavior) of a high-end medical display (Barco Coronis Fusion 6MP DL, MDCC-6130), and a consumer display (Dell 1907FP). Our results indicate that sRGB & the native color space on the Barco Coronis Fusion exhibit the least non-uniformity within their group. However, the remaining degree of perceptual non-uniformity is still significant and there is room for improvement.
Scheme for Low Energy Beam Transport with a Non-Neutralized Section
Energy Technology Data Exchange (ETDEWEB)
Shemyakin, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Prost, L. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2015-04-23
A typical Low Energy Beam Transport (LEBT) design relies on dynamics with nearly complete beam space charge neutralization over the entire length of the LEBT. This paper argues that, for a beam with modest perveance and uniform current density distribution when generated at the source, a downstream portion of the LEBT can be un-neutralized without significant emittance growth.
New continuity estimates of geometric sums
Directory of Open Access Journals (Sweden)
Evgueni Gordienko
2002-01-01
Full Text Available The paper deals with sums of a random number of independent and identically distributed random variables. More specifically, we compare two such sums, which differ from each other in the distributions of their summands. New upper bounds (inequalities for the uniform distance between distributions of sums are established. The right-hand sides of these inequalities are expressed in terms of Zolotarev's and the uniform distances between the distributions of summands. Such a feature makes it possible to consider these inequalities as continuity estimates and to apply them to the study of the stability (continuity of various applied stochastic models involving geometric sums and their generalizations.
A progressive reduce tension method to fabricate Bradbury-Nielsen gates with uniform tension
Kai, Ni; Zhou, Yu
2015-01-01
Bradbury-Nielsen gates (BNG) which consist of two interleaved and electrically isolated sets of wires can be used to modulate the beams of charged particles, particularly ion beams in mass spectrometry and ion mobility spectrometry. The wires of BNG with uniform tension is critical to make sure the BNG work reliable and robust. In our previous work, we have analyzed the problem of wires tension non-uniform that exists in the traditional sequentially winding methods when the metal wire's elastic modulus is much larger than insulations substrate's and developed a template-based transfer method to solve this problem. In this study, we proposed a progressive reduce tension method which does not need template to fabricate BNG with uniform tension. First input the initial parameters to calculate the final progressive reduce tension sequence (FA(i)) through program; then sequentially adjust the weight set according to FA(i) to construct a BNG with uniform tension wires through a home-built device. Wires tension non-...
Lancaster, D. G.; Richter, D.; Curl, R. F.; Tittel, F. K.; Goldberg, L.; Koplow, J.
1999-01-01
We report the generation of up to 0.7 mW of narrow-linewidth (fiber amplifier and a 1.5-micrometers diode-laser-seeded 0.6-W Er/Yb fiber amplifier in periodically poled LiNbO3. A conversion efficiency of 0.09%/W (0.47 mWW-2 cm-1) was achieved. A room-air CH4 spectrum acquired with a compact 80-m multipass cell and a dual-beam spectroscopic configuration indicates an absorption sensitivity of +/-2.8 x 10(-5) (+/-1 sigma), corresponding to a sub-parts-in-10(9) (ppb) CH4 sensitivity (0.8 ppb).
Chakraborty S; Borkakati A.K.
2002-01-01
The flow of a viscous incompressible electrically conducting fluid on a continuous moving flat plate in presence of uniform transverse magnetic field, is studied. The flat plate which is continuously moving in its own plane with a constant speed is considered to be isothermally heated. Assuming the fluid viscosity as an inverse linear function of temperature, the nature of fluid velocity and temperature in presence of uniform magnetic field are shown for changing viscosity parameter at differ...
Impact of heterogeneities on lateral penumbra in uniform scanning proton therapy
Directory of Open Access Journals (Sweden)
Suresh Rana
2013-12-01
Full Text Available Purpose: In the treatment planning of uniform scanning proton therapy, an aperture block is designed for each beam with a margin, which typically includes the lateral penumbra measured in water (homogenous medium. However, during real proton therapy treatment, protons may pass through tissues of different densities within the patient's body before they are stopped. The main aim of this study was to investigate the dependency of lateral penumbra on low- and high-density heterogeneities placed in the plateau and spread-out Bragg peak (SOBP regions.Method: The measurements were performed by placing radiographic films at the isocenter (center of SOBP, and each proton beam was delivered with 150 monitor units using standard beam conditions of the institution. Results and Conclusion: The preliminary results from this study showed that the lateral penumbra of uniform scanning proton beams was less sensitive to the inhomogeneities introduced in the protons beam path. The low-density heterogeneity in the plateau region had more impact on the lateral penumbra when compared to the low-density in the SOBP region. In contrast, the placement of high-density heterogeneity (whether in the plateau or SOBP region produced a very minimal difference. The overall difference in lateral penumbra among different phantoms was within ±1 mm.----------------------Cite this article as:Rana S, Singh H. Impact of heterogeneities on lateral penumbra in uniform scanning proton therapy. Int J Cancer Ther Oncol 2013; 1(2:01026.DOI: http://dx.doi.org/10.14319/ijcto.0102.6
Institute of Scientific and Technical Information of China (English)
陶竑宇
2013-01-01
本文基于 Midas Civil，运用 m 法模拟了桩土相互作用对高速铁路连续梁桥地震响应的影响。实验发现，考虑桩土相互作用时，地震响应明显增大，且地震响应规律差异明显。这是准确计算地震对高速铁路连续梁桥影响的不可忽略因素。%This article bases on Midas Civil, use the method of m to simulate the pile-soil interaction impact on the seismic response of continuous beam bridge in high-speed railway. And the author discovers that when considering the pile-soil interaction, the seismic response is significantly increased, and the differences of the seismic response law are obvious, which is the factor that cannot be ignored to accurately calculate the earthquake on the continuous beam bridge in high-speed rail-way.
Simulating Transient Effects of Pulsed Beams on Beam Intercepting Devices
Richter, Herta; Noah Messomo, Etam
2011-01-01
The development in the physics community towards higher beam power through the possibilities of particle accelerators lead to challenges for the developers of elements which are exposed to effect of particle beams (beam intercepting devices = BIDs). For the design of BIDs, the increasing heat load onto these devices due to energetic and focused beams and - in most cases - their highly pulsed nature has to be taken into account. The physics requirements are sometimes opposed to the current state of the art. As one possibility of many in combining the different aspects for these ambitious demands, two highly developed computer programs, namely FLUKA and ANSYS AUTODYN, were joined for this dissertation. The former is a widely enhanced Monte-Carlo-code which specializes on the interaction of particles with static matter, while the latter is a versatile explicit code for the simulation of highly dynamic processes. Both computer programs were developed intensively over years and are still continuously enhanced in o...
On the weak uniform rotundity of Banach spaces
Directory of Open Access Journals (Sweden)
Wen D. Chang
2003-01-01
Full Text Available We prove that if Xi,i=1,2,…, are Banach spaces that are weak* uniformly rotund, then their lp product space (p>1 is weak* uniformly rotund, and for any weak or weak* uniformly rotund Banach space, its quotient space is also weak or weak* uniformly rotund, respectively.
... Physician Resources Professions Site Index A-Z External Beam Therapy (EBT) External beam therapy (EBT) is a ... follow-up should I expect? What is external beam therapy and how is it used? External beam ...
Uniform Algebras Over Complete Valued Fields
Mason, Jonathan W
2012-01-01
UNIFORM algebras have been extensively investigated because of their importance in the theory of uniform approximation and as examples of complex Banach algebras. An interesting question is whether analogous algebras exist when a complete valued field other than the complex numbers is used as the underlying field of the algebra. In the Archimedean setting, this generalisation is given by the theory of real function algebras introduced by S. H. Kulkarni and B. V. Limaye in the 1980s. This thesis establishes a broader theory accommodating any complete valued field as the underlying field by involving Galois automorphisms and using non-Archimedean analysis. The approach taken keeps close to the original definitions from the Archimedean setting. Basic function algebras are defined and generalise real function algebras to all complete valued fields. Several examples are provided. Each basic function algebra is shown to have a lattice of basic extensions related to the field structure. In the non-Archimedean settin...
Influence on discharge uniformity of electrodes configuration
Zheng Jian; Sui Zhan; Lu Jing Ping; Zheng Kui Xing; Zhang Xiong Jun; Dong Yun; Feng Bin
2002-01-01
Large area glow discharge plasma that is transparent and highly conductive can be used as electrodes in Pockels cell to extend the switch aperture. To investigate this technology, a glow discharging chamber with a clear aperture of 5 cm x 5 cm was constructed, and hollow cathode, button cathode, pin cathode, bar cathode and bar anode were designed and produced. Using CCD imaging system, the discharging uniformity of different cathodes was tested with bar anode and under the different pressure pre-ionization voltage and main discharging voltage. A uniform plasma can be obtained with a hollow cathode when the pre-ionization voltage is about 700 V, the pressure is about 30 Pa, and the main discharging voltage is about 4 kV, which can be used for the plasma electrode of Pockels cell
Non-uniform tube representation of proteins
DEFF Research Database (Denmark)
Hansen, Mikael Sonne
Treating the full protein structure is often neither computationally nor physically possible. Instead one is forced to consider various reduced models capturing the properties of interest. Previous work have used tubular neighborhoods of the C-alpha backbone. However, assigning a unique radius...... might not correctly capture volume exclusion - of crucial importance when trying to understand a proteins $3$d-structure. We propose a new reduced model treating the protein as a non-uniform tube with a radius reflecting the positions of atoms. The tube representation is well suited considering X......-ray crystallographic resolution ~ 3Å while a varying radius accounts for the different sizes of side chains. Such a non-uniform tube better capture the protein geometry and has numerous applications in structural/computational biology from the classification of protein structures to sequence-structure prediction....
Non-Uniform Tube Representation of Proteins
DEFF Research Database (Denmark)
Hansen, Mikael Sonne
Treating the full protein structure is often neither computationally nor physically possible. Instead one is forced to consider various reduced models capturing the properties of interest. Previous work have used tubular neighborhoods of the C-alpha backbone. However, assigning a unique radius...... might not correctly capture volume exclusion - of crucial importance when trying to understand a protein's 3d-structure. We propose a new reduced model treating the protein as a non-uniform tube with a radius reflecting the positions of atoms. The tube representation is well suited considering X......-ray crystallographic resolution ~ 3Å while a varying radius accounts for the different sizes of side chains. Such a non-uniform tube better captures the protein geometry and has numerous applications in structural/computational biology from the classification of protein structures to sequence-structure prediction....
Institute of Scientific and Technical Information of China (English)
史康; 全健; 王福敏; 耿波
2014-01-01
以厦漳跨海大桥北汊南引桥为依托，采用有限元非线性时程分析方法，比较分析了铅芯橡胶支座和盆式橡胶支座对高烈度地区大跨径连续箱梁桥的抗震影响。研究结果表明：铅芯橡胶支座增加了结构在地震作用下的振动周期和主梁梁端位移，减小了固定墩的受力。相比盆式橡胶支座，铅芯橡胶支座可以使主梁梁端位移增加20％～200％，固定墩内力减小36％～80％。说明铅芯橡胶支座能够通过增加主梁位移达到减小桥墩受力的效果，隔震效果明显。该研究成果可为同类型桥梁的抗震设计提供参考。%Based on north south approach spans of Xiamen -zhangzhou cross-sea bridge by using the finite element nonlinear a-nalysis method, the seismic impact is compared between lead -rubber bearing and pot rubber bearing on the long span box girder bridges in high-intensity areas .The results show that the lead -rubber bearing can increase the vibration period and displacement of main beam in earthquake , reduce the force of fixed piers .Compared with pot rubber bearing , adopting lead-rubber bearing can in-crease the end displacement of main grider by 20%to 200%, meanwhile decrease internal force for fixed piers by 36%to 80%.The isolation effect is obvious that lead -rubber bearings can reduce the pier force by increasing the displacement of main beam .The re-search results provide a reference for the same type of bridge seismic design .
Dynamic Uniform Scaling for Multiobjective Genetic Algorithms
DEFF Research Database (Denmark)
Pedersen, Gerulf; Goldberg, D.E.
2004-01-01
Before Multiobjective Evolutionary Algorithms (MOEAs) can be used as a widespread tool for solving arbitrary real world problems there are some salient issues which require further investigation. One of these issues is how a uniform distribution of solutions along the Pareto non-dominated front can......, the issue of obtaining a diverse set of solutions for badly scaled objective functions will be investigated and proposed solutions will be implemented using the NSGA-II algorithm....
Uniform convergence to equilibrium for granular media
Bolley, François; Guillin, Arnaud
2012-01-01
We study the long time asymptotics of a nonlinear, nonlocal equation used in the modelling of granular media. We prove a uniform exponential convergence to equilibrium for degenerately convex and non convex interaction or confinement potentials, improving in particular results by J. A. Carrillo, R. J. McCann and C. Villani. The method is based on studying the dissipation of the Wasserstein distance between a solution and the steady state.
Sequential Testing with Uniformly Distributed Size
Stanislav Anatolyev; Grigory Kosenok
2011-01-01
Sequential procedures of testing for structural stability do not provide enough guidance on the shape of boundaries that are used to decide on acceptance or rejection, requiring only that the overall size of the test is asymptotically controlled. We introduce and motivate a reasonable criterion for a shape of boundaries which requires that the test size be uniformly distributed over the testing period. Under this criterion, we numerically construct boundaries for most popular sequential tests...
Weighted averages, uniform distribution, and strict ergodicity
International Nuclear Information System (INIS)
A circle of problems related to the application of the Riesz and Voronoi summation methods in ergodic theory, number theory, and probability theory is considered. The first digit paradox is discussed, strengthenings of the classical result of Weyl on the uniform distribution of the fractional parts of the values of a polynomial are indicated, and the possibility of sharpening the Birkhoff-Khinchin ergodic theorem is considered. In conclusion, some unsolved problems are listed
Magnetic Propeller for Uniform Magnetic Field Levitation
Krinker, Mark; Bolonkin, Alexander
2008-01-01
Three new approaches to generating thrust in uniform magnetic fields are proposed. The first direction is based on employing Lorentz force acting on partial magnetically shielded 8-shaped loop with current in external magnetic field, whereby a net force rather than a torque origins. Another approach, called a Virtual Wire System, is based on creating a magnetic field having an energetic symmetry (a virtual wire), with further superposition of external field. The external field breaks the symm...
Adjustable, Broadband, Selective Excitation with Uniform Phase
Cano, Kristin E.; Smith, Mari A.; Shaka, A. J.
2002-03-01
An advance in the problem of achieving broadband, selective, and uniform-phase excitation in NMR spectroscopy of liquids is outlined. Broadband means that, neglecting relaxation, any frequency bandwidth may be excited even when the available radiofrequency (RF) field strength is strictly limited. Selective means that sharp transition edges can be created between pure-phase excitation and no excitation at all. Uniform phase means that, neglecting spin-spin coupling, all resonance lines have nearly the same phase. Conventional uniform-phase excitation pulses (e.g., E-BURP), mostly based on amplitude modulation of the RF field, are not broadband: they have an achievable bandwidth that is strictly limited by the peak power available. Other compensated pulses based on adiabatic half-passage, like BIR-4, are not selective. By contrast, inversion pulses based on adiabatic fast passage can be broadband (and selective) in the sense above. The advance outlined is a way to reformulate these frequency modulated (FM) pulses for excitation, rather than just inversion.
Directory of Open Access Journals (Sweden)
Ajab Akbarally
2007-06-01
Full Text Available A new subclass of analytic functions $ k-SP_\\lambda(\\alpha $ is introduced by applying certain operators of fractional calculus to $k$-uniformly starlike and $ k $-uniformly convex functions of order $ \\alpha $. Some theorems on coefficient bounds and growth and distortion theorems for this subclass are found. The radii of close to convexity, starlikeness and convexity for this subclass is also derived.
Siegel, R.; Sparrow, E. M.
1960-01-01
The purpose of this note is to examine in a more precise way how the Nusselt numbers for turbulent heat transfer in both the fully developed and thermal entrance regions of a circular tube are affected by two different wall boundary conditions. The comparisons are made for: (a) Uniform wall temperature (UWT); and (b) uniform wall heat flux (UHF). Several papers which have been concerned with the turbulent thermal entrance region problem are given. 1 Although these analyses have all utilized an eigenvalue formulation for the thermal entrance region there were differences in the choices of eddy diffusivity expressions, velocity distributions, and methods for carrying out the numerical solutions. These differences were also found in the fully developed analyses. Hence when making a comparison of the analytical results for uniform wall temperature and uniform wall heat flux, it was not known if differences in the Nusselt numbers could be wholly attributed to the difference in wall boundary conditions, since all the analytical results were not obtained in a consistent way. To have results which could be directly compared, computations were carried out for the uniform wall temperature case, using the same eddy diffusivity, velocity distribution, and digital computer program employed for uniform wall heat flux. In addition, the previous work was extended to a lower Reynolds number range so that comparisons could be made over a wide range of both Reynolds and Prandtl numbers.
Splitting of high power, cw proton beams
Facco, Alberto; Berkovits, Dan; Yamane, Isao
2007-01-01
A simple method for splitting a high power, continuous wave (cw) proton beam in two or more branches with low losses has been developed in the framework of the EURISOL (European Isotope Separation On-Line adioactive Ion Beam Facility) design study. The aim of the system is to deliver up to 4 MW of H beam to the main radioactive ion beam production target, and up to 100 kWof proton beams to three more targets, simultaneously. A three-step method is used, which includes magnetic neutralization of a fractionof the main H- beam, magnetic splitting of H- and H0, and stripping of H0 to H+. The method allowsslow raising and individual fine adjustment of the beam intensity in each branch.
Diffraction analysis of beams for barcode scanning
Eastman, Jay M.; Quinn, Anna M.
1991-02-01
Laser based bar code scanners utilize large f/# beams to attain a large depth of focus. The intensity cross-section of the laser beam is generally not uniform but is frequently approximated by a Gaussian intensity profile. In the case of laser diodes the beam cross-section is a two dimensional distribution. It is well known that the focusing properties of large f/# Gaussian beams differ from the predictions of ray tracing techniques. Consequently analytic modeling of laser based bar code scanning systems requires techniques based on diffraction rather than on ray tracing in order to obtain agreement between theory and practice. The line spread function of the focused laser beam is generally the parameter of interest due to the one-dimensional nature of the bar code symbol. Some bar code scanners utilize an anamorphic optical system to produce a beam that that maintains an elliptical cross-section over an extended depth of focus. This elliptical beam shape is used to average over voids and other printing defects that occur in real world symbols. Since the scanner must operate over the maximum possible depth of field the beam emergent from the scanner must be analyzed in both its near field and far field regions in order to properly model the performance of the scanner.
Beam Combination for Sparse Aperture Telescopes Project
National Aeronautics and Space Administration — This proposal is for funding to continue development of an alternative beam combiner for Stellar Imager (SI), a 30-aperture, interferometric telescope chosen as one...
On uniform approximation by n-analytic functions on closed sets in C
Energy Technology Data Exchange (ETDEWEB)
Boivin, A [Department of Mathematics, University of Western Ontario, London, Ontario (Canada); Gauthier, P M [Universite de Montreal, Quebec (Canada); Paramonov, P V [M.V. Lomonosov Moscow State University, Moscow (Russian Federation)
2004-06-30
Necessary and (or) sufficient conditions on a closed set F subset of C are given for any function f, continuous on F and n-analytic on F{sup 0}, to be the uniform limit on F of a sequence of n-analytic entire or n-analytic meromorphic functions.
Directory of Open Access Journals (Sweden)
M. G. Crandall
1999-07-01
Full Text Available We study existence of continuous weak (viscosity solutions of Dirichlet and Cauchy-Dirichlet problems for fully nonlinear uniformly elliptic and parabolic equations. Two types of results are obtained in contexts where uniqueness of solutions fails or is unknown. For equations with merely measurable coefficients we prove solvability of the problem, while in the continuous case we construct maximal and minimal solutions. Necessary barriers on external cones are also constructed.
Beam quality measure for vector beams.
Ndagano, Bienvenu; Sroor, Hend; McLaren, Melanie; Rosales-Guzmán, Carmelo; Forbes, Andrew
2016-08-01
Vector beams have found a myriad of applications, from laser materials processing to microscopy, and are now easily produced in the laboratory. They are usually differentiated from scalar beams by qualitative measures, for example, visual inspection of beam profiles after a rotating polarizer. Here we introduce a quantitative beam quality measure for vector beams and demonstrate it on cylindrical vector vortex beams. We show how a single measure can be defined for the vector quality, from 0 (purely scalar) to 1 (purely vector). Our measure is derived from a quantum toolkit, which we show applies to classical vector beams. PMID:27472580
A Uniform Framework of Global Nuclear Materials Management
International Nuclear Information System (INIS)
Global Nuclear Materials Management (GNMM) anticipates and supports a growing international recognition of the importance of uniform, effective management of civilian, excess defense, and nuclear weapons materials. We expect thereto be a continuing increase in both the number of international agreements and conventions on safety, security, and transparency of nuclear materials, and the number of U.S.-Russian agreements for the safety, protection, and transparency of weapons and excess defense materials. This inventory of agreements and conventions may soon expand into broad, mandatory, international programs that will include provisions for inspection, verification, and transparency, To meet such demand the community must build on the resources we have, including State agencies, the IAEA and regional organizations. By these measures we will meet the future expectations for monitoring and inspection of materials, maintenance of safety and security, and implementation of transparency measures
A Uniform Framework of Global Nuclear Materials Management
Energy Technology Data Exchange (ETDEWEB)
Dupree, S.A.; Mangan, D.L.; Sanders, T.L; Sellers, T.A.
1999-04-20
Global Nuclear Materials Management (GNMM) anticipates and supports a growing international recognition of the importance of uniform, effective management of civilian, excess defense, and nuclear weapons materials. We expect thereto be a continuing increase in both the number of international agreements and conventions on safety, security, and transparency of nuclear materials, and the number of U.S.-Russian agreements for the safety, protection, and transparency of weapons and excess defense materials. This inventory of agreements and conventions may soon expand into broad, mandatory, international programs that will include provisions for inspection, verification, and transparency, To meet such demand the community must build on the resources we have, including State agencies, the IAEA and regional organizations. By these measures we will meet the future expectations for monitoring and inspection of materials, maintenance of safety and security, and implementation of transparency measures.
On acoustic wave generation in uniform shear flow
Gogoberidze, G.
2016-07-01
The linear dynamics of acoustic waves and vortices in uniform shear flow is studied. For flows with very low shear rates, the dynamics of perturbations is adiabatic and can be described by the WKB approximation. However, for flows with moderate and high shear rates the WKB approximation is not appropriate, and alternative analysis shows that two important phenomena occur: acoustic wave over-reflection and wave generation by vortices. The later phenomenon is a known linear mechanisms for sound generation in shear flows, a mechanism that is related to the continuous spectrum that arises in linear shear flow dynamics. A detailed analytical study of these phenomena is performed and the main quantitative and qualitative characteristics of the radiated acoustic field are obtained and analyzed.
Energy Technology Data Exchange (ETDEWEB)
Temporal, M., E-mail: mauro.temporal@hotmail.com [Centre de Mathématiques et de Leurs Applications, ENS Cachan and CNRS, 61 Av. du President Wilson, F-94235 Cachan Cedex (France); Canaud, B. [CEA, DIF, F-91297 Arpajon Cedex (France); Garbett, W. J. [AWE plc, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Ramis, R. [ETSI Aeronáutica y del Espacio, Universidad Politécnica de Madrid, 28040 Madrid (Spain)
2015-10-15
The implosion uniformity of a directly driven spherical inertial confinement fusion capsule is considered within the context of the Laser Mégajoule configuration. Two-dimensional (2D) hydrodynamic simulations have been performed assuming irradiation with two laser beam cones located at 49° and 131° with respect to the axis of symmetry. The laser energy deposition causes an inward shock wave whose surface is tracked in time, providing the time evolution of its non-uniformity. The illumination model has been used to optimize the laser intensity profiles used as input in the 2D hydro-calculations. It is found that a single stationary laser profile does not maintain a uniform shock front over time. To overcome this drawback, it is proposed to use two laser profiles acting successively in time, in order to dynamically stabilize the non-uniformity of the shock front.
Beam Induced Pressure Rise at RHIC
Zhang, S Y; Bai, Mei; Blaskiewicz, Michael; Cameron, Peter; Drees, Angelika; Fischer, Wolfram; Gullotta, Justin; He, Ping; Hseuh Hsiao Chaun; Huang, Haixin; Iriso, Ubaldo; Lee, Roger C; Litvinenko, Vladimir N; MacKay, William W; Nicoletti, Tony; Oerter, Brian; Peggs, Steve; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smart, Loralie; Snydstrup, Louis; Thieberger, Peter; Trbojevic, Dejan; Wang, Lanfa; Wei, Jie; Zeno, Keith
2005-01-01
Beam induced pressure rise in RHIC warm sections is currently one of the machine intensity and luminosity limits. This pressure rise is mainly due to electron cloud effects. The RHIC warm section electron cloud is associated with longer bunch spacings compared with other machines, and is distributed non-uniformly around the ring. In addition to the countermeasures for normal electron cloud, such as the NEG coated pipe, solenoids, beam scrubbing, bunch gaps, and larger bunch spacing, other studies and beam tests toward the understanding and counteracting RHIC warm electron cloud are of interest. These include the ion desorption studies and the test of anti-grazing ridges. For high bunch intensities and the shortest bunch spacings, pressure rises at certain locations in the cryogenic region have been observed during the past two runs. Beam studies are planned for the current 2005 run and the results will be reported.
Nonlocal analysis of finite-beam-driven instabilities
Serizawa, Y.; Dum, C. T.
1992-01-01
The fully kinetic integral eigenmode equation in wave-number space is used to describe the nonlocal behavior of electrostatic waves in an electron-beam plasma, which are studied in the low-temperature-beam regime and the warm-beam regime. The case of strongly magnetized electrons and unmagnetized ions, which corresponds to the waves in a frequency range from the lower-hybrid to the electron plasma frequency, is examined. Three wave modes are found. The first group consists of modes that have dispersive properties similar to the uniform, infinite beam-plasma system. Depending on the beam width, the growth rates are strongly reduced. The second group, surface modes, are localized at the periphery of the beam region and are less unstable than the unstable modes of the first group. The third group represents natural oscillations of the background plasma. These modes are virtually unaffected by the beam.
Fabrication of a uniformly sized fenofibrate microemulsion by membrane emulsification.
Pradhan, Roshan; Lee, Dong Won; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh
2013-01-01
Fenofibrate-loaded microemulsions composed of Labrafil M 1944 CS, Capryol PGMC and fenofibrate as the dispersed phase and Labrasol in demineralised water as the continuous phase were prepared by utilising a Shirasu-porous-glass (SPG) membrane emulsification technique. The process parameters were optimised by adjusting the feed pressure (15-45 kPa), agitator speed (250-800 rpm) and temperature of the continuous phase (25-45°C). As a result, narrowly distributed microemulsions were obtained via SPG membrane emulsification at an agitator speed of 250 rpm, a feed pressure of 30 kPa and a continuous phase temperature of 25°C. Furthermore, TEM images clearly showed that the microemulsion prepared by SPG membrane emulsification had a uniform, spherical morphology with a narrow size distribution. Our results indicated that the SPG membrane emulsification technique is highly efficient for the preparation of narrowly distributed microemulsions with relatively smaller particle sizes compared with the common stirring method. PMID:22657749
Polar POLICRYPS Diffractive Structures Generate Cylindrical Vector Beams
Alj, Domenico; Volpe, Giovanni; Caputo, Roberto; Umeton, Cesare
2015-01-01
Local shaping of the polarization state of a light beam is appealing for a number of applications. This can be achieved by employing devices containing birefringent materials. In this article, we present one such device that permits one to convert a uniformly circularly polarized beam into a cylindrical vector beam (CVB). This device has been fabricated by exploiting the POLICRYPS photocuring technique. It is a liquid-crystal-based optical diffraction grating featuring polar symmetry of the director alignment. We have characterized the resulting CVB profile and polarization for the cases of left and right circularly polarized incoming beams.
Propagation of electron and positron beams in long, dense plasmas
Muggli, Patric; Blue, Brent; Clayton, Chris; Decker, Franz-Joseph; Hogan, Mark; Hunag, Chengkun; Joshi, Chan; Katsouleas, Tom; Lu, Wei; Mori, Warren; O'Connell, Caollionn; Siemann, Robert; Walz, Dieter; Zhou, Miaomiao
2008-04-01
Electron beams with density larger than the plasma density can propagate through plasmas without significant emittance growth. The electron beam expels the plasma electrons from the bunch volume and propagate in a pure, uniform ion column. In contrast, positron beams attract plasma electrons that flow through the positron bunch. As a result the plasma focusing force is nonlinear, a charge halo forms around the bunch, and the bunch emittance grows. After some distance into the plasma, the bunch emittance reaches an approximately constant value, and the beam and the plasma focusing force reach a steady state. Experimental results obtained with electron and positron bunches, as well as numerical simulation results will be presented.
Polar POLICRYPS diffractive structures generate cylindrical vector beams
Energy Technology Data Exchange (ETDEWEB)
Alj, Domenico; Caputo, Roberto, E-mail: roberto.caputo@fis.unical.it; Umeton, Cesare [Department of Physics and CNR-NANOTEC University of Calabria, I-87036 Rende (CS) (Italy); Paladugu, Sathyanarayana [Soft Matter Lab, Department of Physics, Bilkent University, Ankara 06800 (Turkey); Volpe, Giovanni [Soft Matter Lab, Department of Physics, Bilkent University, Ankara 06800 (Turkey); UNAM-National Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey)
2015-11-16
Local shaping of the polarization state of a light beam is appealing for a number of applications. This can be achieved by employing devices containing birefringent materials. In this article, we present one such enables converting a uniformly circularly polarized beam into a cylindrical vector beam (CVB). This device has been fabricated by exploiting the POLICRYPS (POlymer-LIquid CRYstals-Polymer-Slices) photocuring technique. It is a liquid-crystal-based optical diffraction grating featuring polar symmetry of the director alignment. We have characterized the resulting CVB profile and polarization for the cases of left and right circularly polarized incoming beams.
Fabrication and evaluation of uniform and gradient density epoxies
Energy Technology Data Exchange (ETDEWEB)
Domeier, L.A.; Skala, D.M.; Goods, S.H. [and others
1997-11-01
Filled epoxy materials which vary in density in a designed manner have been fabricated and their mechanical properties evaluated. Density variations were produced by incorporating different volume fractions of either glass microballoons (GMB) or alumina. Several different sample types were evaluated including uniform density (0.8 g/cm{sup 3} < {rho} < 2.0 g/cm{sup 3}) samples and gradient density samples (GMB only, 0.8 g/cm{sup 3} < {rho} < 1.2 g/cm{sup 3}). The uniform density specimens were evaluated for the effects of filler type and concentration on modulus and toughness. Results indicated that addition of alumina filler significantly increased the resulting modulus while addition of GMB had little measurable effect. These differences could be understood in terms of the differing moduli of the additives relative to that of the epoxy matrix. In the former case the alumina particulates had a modulus much greater than that of the epoxy while in the latter case, the modulus of the GMB additive was only slightly greater than that of the matrix. Addition of either filler significantly degraded the toughness of the composite specimens and precluded the use of gradients to enhance toughness performance. Discontinuous {open_quotes}block{close_quotes} gradients used for testing were fabricated by simple sequential pours of formulations with different GMB loadings and were evaluated for modulus, strength and ductility. Continuous gradients were fabricated in process studies by programmed shifts in the peristaltic pumping/mixing ratio of epoxies filled with either alumina or GMB. None of the continuous gradient materials were mechanically tested. These results suggest that applications utilizing gradient materials containing alumina and similar high modulus fillers to provide designed stiffness rather than improved toughness are the most appropriate targets for future investigation.
Radiative processes of uniformly accelerated entangled atoms
Menezes, G
2015-01-01
We study radiative processes of uniformly accelerated entangled atoms, interacting with an electromagnetic field prepared in the Minkowski vacuum state. We discuss the structure of the rate of variation of the atomic energy for two atoms travelling in different hyperbolic world lines. We identify the contributions of vacuum fluctuations and radiation reaction to the generation of entanglement as well as to the decay of entangled states. Our results resemble the situation in which two inertial atoms are coupled individually to two spatially separated cavities at different temperatures. In addition, for equal accelerations we obtain that the maximally entangled antisymmetric Bell state is a decoherence-free state.
Uniform Approximation of Vapnik-Chervonenkis Classes
Adams, Terrence M
2010-01-01
For any family of measurable sets in a probability space, we show that either (i) the family has infinite Vapnik-Chervonenkis (VC) dimension or (ii) for every epsilon > 0 there is a finite partition pi such the pi-boundary of each set has measure at most epsilon. Immediate corollaries include the fact that a family with finite VC dimension has finite bracketing numbers, and satisfies uniform laws of large numbers for every ergodic process. From these corollaries, we derive analogous results for VC major and VC graph families of functions.
A uniform system for evaluation of substances
Energy Technology Data Exchange (ETDEWEB)
Zandt, P.T.J. van der [Directorate-General for Environmental Protection, The Hague (Netherlands); Vermeire, T.J. [National Inst. for Public Health and Environmental Protection, Bilthoven (Netherlands); Roelfzeme, H. [Directorate-General for Public Health, Rijswijk (Netherlands)
1994-12-31
One of the action points that have been formulated in the Netherlands` first Environmental Policy Plan was the development, in co-operation with industry, of a system for the rapid screening of potential risks of chemicals. In the ``Uniform System for Evaluation of Substances`` (USES 1.0) project different methods for assessment of risks to man and environment that had been developed for new and existing substances and pesticides have been integrated and harmonized. USES 1.0 provides a decision-supporting tool that may be applied by governments and industries in both nation and international (OECD, EU) risk management processes.
Quantum Radiation of Uniformly Accelerated Spherical Mirrors
Frolov, V
2001-01-01
We study quantum radiation generated by a uniformly accelerated motion of small spherical mirrors. To obtain Green's function for a scalar massless field we use Wick's rotation. In the Euclidean domain the problem is reduced to finding an electric potential in 4D flat space in the presence of a metallic toroidal boundary. The latter problem is solved by a separation of variables. After performing an inverse Wick's rotation we obtain the Hadamard function in the wave-zone regime and use it to calculate the vacuum fluctuations and the vacuum expectation for the energy density flux in the wave zone.
Radionic Non-uniform Black Strings
Tamaki, Takashi; Kanno, Sugumi; Soda, Jiro
2003-01-01
Non-uniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a non-trivial hair of the black strings. From the brane point of view, the black string appears as the deformed dilatonic black hole which becomes dilatonic black hole in the single brane limit and reduces to the Reissner-Nordstr\\"om black hole in the close limit of two-branes. The stability of solutions is demonstrated using the catastrophe theory. From ...
Simulations of beam emittance growth from the collectiverelaxation of space-charge nonuniformities
Energy Technology Data Exchange (ETDEWEB)
Lund, Steven M.; Grote, David P.; Davidson, Ronald C.
2004-05-01
Beams injected into a linear focusing channel typically have some degree of space-charge nonuniformity. For unbunched beams with high space-charge intensity propagating in linear focusing channels, Debye screening of self-field interactions tends to make the transverse density profile flat. An injected particle distribution with a large systematic charge nonuniformity will generally be far from an equilibrium of the focusing channel and the initial condition will launch a broad spectrum of collective modes. These modes can phase-mix and experience nonlinear interactions which result in an effective relaxation to a more thermal-equilibrium-like distribution characterized by a uniform density profile. This relaxation transfers self-field energy from the initial space-charge nonuniformity to the local particle temperature, thereby increasing beam phase space area (emittance growth). Here they employ two-dimensional electrostatic particle in cell (PIC) simulations to investigate the effects of initial transverse space-charge nonuniformities on the equality of beams with high space-charge intensity propagating in a continuous focusing channel. Results are compared to theoretical bounds of emittance growth developed in previous studies. Consistent with earlier theory, it is found that a high degree of initial distribution nonuniformity can be tolerated with only modest emittance growth and that beam control can be maintained. The simulations also provide information on the rate of relaxation and characteristic levels of fluctuations in the relaxed states. This research suggests that a surprising degree of initial space-charge nonuniformity can be tolerated in practical intense beam experiments.
2015-01-01
Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure. I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...
International Nuclear Information System (INIS)
The main part of this thesis consists of 15 published papers, in which the numerical Beam Propagating Method (BPM) is investigated, verified and used in a number of applications. In the introduction a derivation of the nonlinear Schroedinger equation is presented to connect the beginning of the soliton papers with Maxwell's equations including a nonlinear polarization. This thesis focuses on the wide use of the BPM for numerical simulations of propagating light and particle beams through different types of structures such as waveguides, fibers, tapers, Y-junctions, laser arrays and crystalline solids. We verify the BPM in the above listed problems against other numerical methods for example the Finite-element Method, perturbation methods and Runge-Kutta integration. Further, the BPM is shown to be a simple and effective way to numerically set up the Green's function in matrix form for periodic structures. The Green's function matrix can then be diagonalized with matrix methods yielding the eigensolutions of the structure. The BPM inherent transverse periodicity can be untied, if desired, by for example including an absorptive refractive index at the computational window edges. The interaction of two first-order soliton pulses is strongly dependent on the phase relationship between the individual solitons. When optical phase shift keying is used in coherent one-carrier wavelength communication, the fiber attenuation will suppress or delay the nonlinear instability. (orig.)
The Non-uniform Fast Fourier Transform in Computed Tomography
Tang, Junqi
2016-01-01
This project is aimed at designing the fast forward projection algorithm and also the backprojection algorithm for cone beam CT imaging systems with circular X-ray source trajectory. The principle of the designs is based on utilizing the potential computational efficiency which the Fourier Slice Theorem and the Non-uniform Fast Fourier Transform (NUFFT) will bring forth. In this Masters report, the detailed design of the NUFFT based forward projector including a novel 3D (derivative of) Radon space resampling method will be given. Meanwhile the complexity of the NUFFT based forward projector is analysed and compared with the non-Fourier based CT projector, and the advantage of the NUFFT based forward projection in terms of the computational efficiency is demonstrated in this report. Base on the design of the forward algorithm, the NUFFT based 3D direct reconstruction algorithm will be derived. The experiments will be taken to test the performance of the forward algorithm and the backprojection algorithm to sh...
Beam Loss Monitors at the ESRF
Joly, B; Naylor, G A
2000-01-01
The European Synchrotron radiation facility is a third generation x-ray source providing x-rays on a continuous basis. As a facility available to external users, the monitoring of radiation caused by the loss of high-energy stored beam is of great concern. A network of beam loss monitors has been installed inside the storage ring tunnel so as to detect and localize the slow loss of electrons during a beam decay. This diagnostic tool allows optimization of beam parameters and physical aperture limits as well as giving useful information on the machine to allow the lifetime to be optimized and defects localized.
Uniformly accelerated observer in a thermal bath
Kolekar, Sanved
2013-01-01
We investigate the quantum field aspects in flat spacetime for an uniformly accelerated observer moving in a thermal bath. In particular, we obtain an exact closed expression of the reduced density matrix for an uniformly accelerated observer with acceleration $a = 2\\pi T$ when the state of the quantum field is a thermal bath at temperature $T^\\prime$. We find that the density matrix has a simple form with an effective partition function $Z$ being a product, $Z = Z_T Z_{T^\\prime}$, of two thermal partition functions corresponding to temperatures $T$ and $T^\\prime$ and hence is not thermal, even when $T = T^\\prime$. We show that, even though the partition function has a product structure, the two thermal baths are, in fact, interacting systems; although in the high frequency limit $\\omega_k \\gg T$ and $\\omega_k \\gg T^\\prime$, the interactions are found to become sub-dominant. We further demonstrate that the resulting spectrum of the Rindler particles can be interpreted in terms of spontaneous and stimulated em...
Lang's conjectures, conjecture H, and uniformity
Abramovich, D
1995-01-01
The purpose of this note is to wish a happy birthday to Professor Lucia Caporaso.* We prove that Conjecture H of Caporaso et. al. ([CHarM], sec. 6) together with Lang's conjecture implies the uniformity of rational points on varieties of general type, as predicted in [CHarM]; a few applications in arithmetic and geometry are stated. Let X be a variety of general type defined over a number field K. It was conjectured by S. Lang that the set of rational points X(K) is not Zariski dense in X. In the paper [CHarM] of L. Caporaso, J. Harris and B. Mazur it is shown that the above conjecture of Lang implies the existence of a uniform bound on the number of K-rational points of all curves of fixed genus g over K. The paper [CHarM] has immediately created a chasm among arithmetic geometers. This chasm, which often runs right in the middle of the personalities involved, divides between loyal believers of Lang's conjecture, who marvel in this powerful implication, and the disbelievers, who try (so far in vain) to use t...
THERMAL BLOOMING OF HIGH POWER LASER BEAMS
Philbert, M.; Billard, M.; Fertin, G.; Lefèvre, J.
1980-01-01
With a view to better predicting the effects of thermal defocusing within the atmosphere, an experimental simulation set-up has been designed at ONERA. This consists essentially of a vertical airtight cell containing a gas or gas mixture sufficiently absorbing to induce "blooming" of a CO2 laser beam over a distance of about 3 m. A return wind tunnel, integrated within the cell, creates a uniform wind on the beam propagation path ; the wind velocity may be precisely adjusted between 0.1 and 2...
Generalized Continued Logarithms and Related Continued Fractions
Borwein, Jonathan M.; Hare, Kevin G.; Lynch, Jason G.
2016-01-01
We study continued logarithms as introduced by Bill Gosper and studied by J. Borwein et. al.. After providing an overview of the type I and type II generalizations of binary continued logarithms introduced by Borwein et. al., we focus on a new generalization to an arbitrary integer base $b$. We show that all of our so-called type III continued logarithms converge and all rational numbers have finite type III continued logarithms. As with simple continued fractions, we show that the continued ...
Dynamic Modeling of a Non-Uniform Flexible Tail for a Robotic Fish
Institute of Scientific and Technical Information of China (English)
Phi Luan Nguyen; Van Phu Do; Byung Ryong Lee
2013-01-01
In this paper,a non-uniform flexible tail of a fish robot was presented and the dynamic model was developed.In this model,the non-uniform flexible tail was modeled by a rotary slender beam.The hydrodynamics forces,including the reactive force and resistive force,were analyzed in order to derive the governing equation.This equation is a fourth-order in space and second-order in time Partial Differential Equation (PDE) of the lateral movement function.The coefficients of this PDE were not constants because of the non-uniform beams,so they were approximated by exponential functions in order to obtain an analytical solution.This solution describes the lateral movement of the flexible tail as a function of material,geometrical and actuator properties.Experiments were then carried out and compared to simulations.It was proved that the proposed model is suitable for predicting the real behavior of fish robots.
Rubber-induced uniform laser shock wave pressure for thin metal sheets microforming
Energy Technology Data Exchange (ETDEWEB)
Shen, Zongbao, E-mail: szb@ujs.edu.cn; Wang, Xiao; Liu, Huixia; Wang, Yayuan; Wang, Cuntang
2015-02-01
Highlights: • The rubber is introduced to smooth laser shock wave pressure. • The mechanism of rubber-induced smoothing effect is proposed. • Smoothing effect is mainly due to the radial expansion of plasma cloud on rubber. • The good surface quality can be obtained under rubber dynamic loading. - Abstract: Laser shock microforming of thin metal sheets is a new high velocity forming technique, which employs laser shock wave to deform the thin metal sheets. The spatial distribution of forming pressure is mainly dependent on the laser beam. A new type of laser shock loading method is introduced which gives a uniform pressure distribution. A low density rubber is inserted between the laser beam and the thin metal sheets. The mechanism of rubber-induced smoothing effect on confined laser shock wave is proposed. Plasticine is used to perform the smoothing effect experiments due to its excellent material flow ability. The influence of rubber on the uniformity of laser shock wave pressure is studied by measuring the surface micro topography of the deformed plasticine. And the four holes forming experiment is used to verify the rubber-induced uniform pressure on thin metal sheets surface. The research results show the possibility of smoothing laser shock wave pressure using rubber. And the good surface quality can be obtained under rubber dynamic loading.
Rubber-induced uniform laser shock wave pressure for thin metal sheets microforming
Shen, Zongbao; Wang, Xiao; Liu, Huixia; Wang, Yayuan; Wang, Cuntang
2015-02-01
Laser shock microforming of thin metal sheets is a new high velocity forming technique, which employs laser shock wave to deform the thin metal sheets. The spatial distribution of forming pressure is mainly dependent on the laser beam. A new type of laser shock loading method is introduced which gives a uniform pressure distribution. A low density rubber is inserted between the laser beam and the thin metal sheets. The mechanism of rubber-induced smoothing effect on confined laser shock wave is proposed. Plasticine is used to perform the smoothing effect experiments due to its excellent material flow ability. The influence of rubber on the uniformity of laser shock wave pressure is studied by measuring the surface micro topography of the deformed plasticine. And the four holes forming experiment is used to verify the rubber-induced uniform pressure on thin metal sheets surface. The research results show the possibility of smoothing laser shock wave pressure using rubber. And the good surface quality can be obtained under rubber dynamic loading.
From Electron Beams to Photon Beams
International Nuclear Information System (INIS)
n this article I try to report at the best the events and the emotions I experienced, together with my colleagues, when I was a young researcher working at the Frascati Center of CNEN. In the middle of 70’s the high energy physics activities carried out in Frascati were transferred from CNEN to INFN (Istituto Nazionale Fisica Nucleare) and the personnel had the chance to chose to continue to work at the CNEN (obviously in a different research field) or to continue to work in high energy physics, but at the INFN. I decided to remain at the CNEN and, consequently, I had to change my research activity. I moved from the high energy accelerators research field to the lasers research field in which, at that time at the CNEN, a new interesting project on “uranium laser isotope separation” was just starting. This article is focused on the theoretical and experimental development activity, carried out in the years 70’s-80’s at the CNEN Frascati Center, on a quite particular kind of laser to be utilized in that project. In this laser the active medium is not made of atoms or molecules but is a beam of free electrons running along a spatially periodic magnetic structure: this laser is the “Free Electron Laser”
Airy beam optical parametric oscillator.
Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K
2016-01-01
Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond). PMID:27143582
Airy beam optical parametric oscillator.
Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K
2016-05-04
Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).
Airy beam optical parametric oscillator
Aadhi, A.; Chaitanya, N. Apurv; Jabir, M. V.; Vaity, Pravin; Singh, R. P.; Samanta, G. K.
2016-05-01
Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51–1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).
On the Adaptive Beam Forming Performance of a Multi-Beam Antenna
Institute of Scientific and Technical Information of China (English)
JIANGZe; DUHuiping; RUANYingzheng
2004-01-01
The adaptive beam forming performance of a new multi-beam adaptive antenna, which is configured by Fresnel zone phase-correcting plate (FZP) and uniformly spaced feeds array at FZP focusing plane, is investigated by considering the mobile to base station or reverse link in spread spectrum mobile communication scenes. With the specialized configuration of the antenna, the incoming wave signal maps from angular distribution to field distribution in the focal plane where the array is set. The“Beamformer-RAKE” receiver structure, which is suggested by existing CDMA standard, is used to evaluate the performance improvement of the suggested multi-beam antenna. The corresponding estimators for the beam-forming weight vector in the presence of angular spreads are derived out with the use of code filtering approach both in the case of M-ary orthogonal modulation with coherent and non-coherent RAKE combining receiver. Numerical simulation is used to compare the different bit error rate effects with the changes of angular spread, number of antennas and multipath structure both with the models of the one suggested here and the normal Uniformly spaced linear array (ULA) under the influence of co-channel interferences and white Gaussian noise. All the results suggest that the FZP-based multi-beam antenna have a better performance on adaptive beam forming in the specialized scenes.
Beam-beam effects in the Tevatron
Energy Technology Data Exchange (ETDEWEB)
Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R.S.; Sen, T.; Tollestrup, A.; Valishev, A.; Zhang, X.L.; /Fermilab
2005-01-01
The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.
Complex locally uniform rotundity of Musielak-Orlicz spaces
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The concepts of complex locally uniform rotundity and complex locally uniformly rotund point are introduced. The sufficient and necessary conditions of them are given in complex Musielak-Orlicz spaces.
78 FR 34020 - Federal Acquisition Regulation; Uniform Procurement Identification
2013-06-06
... procurement transactions. A number of public comments received during the rulemaking process expressed... 9000-AM60 Federal Acquisition Regulation; Uniform Procurement Identification AGENCY: Department of... Acquisition Regulation (FAR) to implement a uniform Procurement Instrument Identification (PIID)...
Kwon, Soon Gu; Hyeon, Taeghwan
2008-12-01
Nanocrystals exhibit interesting electrical, optical, magnetic, and chemical properties not achieved by their bulk counterparts. Consequently, to fully exploit the potential of nanocrystals, the synthesis of nanocrystals must focus on producing materials with uniform size and shape. Top-down physical processes can produce large quantities of nanocrystals, but controlling the size is difficult with these methods. On the other hand, colloidal chemical synthetic methods can produce uniform nanocrystals with a controlled particle size. In this Account, we present our synthesis of uniform nanocrystals of various shapes and materials, and we discuss the kinetics of nanocrystal formation. We employed four different synthetic approaches including thermal decomposition, nonhydrolytic sol-gel reactions, thermal reduction, and use of reactive chalcogen reagents. We synthesized uniform oxide nanocrystals via heat-up methods. This method involved slowly heat-up reaction mixtures composed of metal precursors, surfactants, and solvents from room temperature to high temperature. We then held reaction mixtures at an aging temperature for a few minutes to a few hours. Kinetics studies revealed a three-step mechanism for the synthesis of nanocrystals through the heat-up method with size distribution control. First, as metal precursors thermally decompose, monomers accumulate. At the aging temperature, burst nucleation occurs rapidly; at the end of this second phase, nucleation stops, but continued diffusion-controlled growth leads to size focusing to produce uniform nanocrystals. We used nonhydrolytic sol-gel reactions to synthesize various transition metal oxide nanocrystals. We employed ester elimination reactions for the synthesis of ZnO and TiO(2) nanocrystals. Uniform Pd nanoparticles were synthesized via a thermal reduction reaction induced by heating up a mixture of Pd(acac)(2), tri-n-octylphosphine, and oleylamine to the aging temperature. Similarly, we synthesized
Stability and Halo Formation in Axisymmetric Intense Beams
Gluckstern, R L; Gluckstern, Robert L.; Kurennoy, Sergey S.
1998-01-01
Beam stability and halo formation in high-intensity axisymmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune depression - mismatch space is explored for the uniform (KV) distribution of the particle transverse-phase-space density, as well as for more realistic ones (in particular, the water-bag distribution), to determine the stability limits and halo parameters. The numerical results show an agreement with predictions of the analytical model for halo formation (R.L. Gluckstern, Phys. Rev. Letters, 73 (1994) 1247).
Stability and Halo Formation in Axisymmetric Intense Beams.
Gluckstern, Robert L.; Kurennoy, Sergey S.
1997-05-01
Beam stability and halo formation in high-intensity axisymmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune depression - mismatch space is explored for the uniform distribution of the particle transverse phase space density (Kapchinsky-Vladimirsky), as well as for more realistic ones (in particular, the water-bag distribution), to determine the stability limits and halo parameters. The numerical results obtained are compared and show an agreement with the predictions of the analytical model for halo formation developed earlier (R.L. Gluckstern, Phys. Rev. Lett., 73), 1247 (1994)..
Stability and halo formation in axisymmetric intense beams
Energy Technology Data Exchange (ETDEWEB)
Gluckstern, R.L. [Univ. of Maryland, College Park, MD (United States); Kurennoy, S.S. [Los Alamos National Lab., NM (United States)
1997-10-01
Beam stability and halo formation in high-intensity axisymmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune depression-mismatch space is explored for the uniform (KV) distribution of the particle transverse-phase-space density, as well as for more realistic ones (in particular, the water-bag distribution), to determine the stability limits and halo parameters. The numerical results show an agreement with predictions of the analytical model for halo formation.
Skupsky, Stanley; Kessler, Terrance J.; Short, Robert W.; Craxton, Stephen; Letzring, Samuel A.; Soures, John
1991-01-01
In an SSD (smoothing by spectral dispersion) system which reduces the time-averaged spatial variations in intensity of the laser light to provide uniform illumination of a laser fusion target, an electro-optic phase modulator through which a laser beam passes produces a broadband output beam by imposing a frequency modulated bandwidth on the laser beam. A grating provides spatial and angular spectral dispersion of the beam. Due to the phase modulation, the frequencies ("colors") cycle across the beam. The dispersed beam may be amplified and frequency converted (e.g., tripled) in a plurality of beam lines. A distributed phase plate (DPP) in each line is irradiated by the spectrally dispersed beam and the beam is focused on the target where a smooth (uniform intensity) pattern is produced. The color cycling enhances smoothing and the use of a frequency modulated laser pulse prevents the formation of high intensity spikes which could damage the laser medium in the power amplifiers.
Liouville theory and uniformization of four-punctured sphere
Hadasz, L; Hadasz, Leszek; Jaskolski, Zbigniew
2006-01-01
Few years ago Zamolodchikov and Zamolodchikov proposed an expression for the 4-point classical Liouville action in terms of the 3-point actions and the classical conformal block. In this paper we develop a method of calculating the uniformizing map and the uniformizing group from the classical Liouville action on n-punctured sphere and discuss the consequences of Zamolodchikovs conjecture for an explicit construction of the uniformizing map and the uniformizing group for the sphere with four punctures.
Uniform Approximation and Bracketing Properties of VC classes
Adams, Terrence M
2010-01-01
We show that the sets in a family with finite VC dimension can be uniformly approximated within a given error by a finite partition. Immediate corollaries include the fact that VC classes have finite bracketing numbers, satisfy uniform laws of averages under strong dependence, and exhibit uniform mixing. Our results are based on recent work concerning uniform laws of averages for VC classes under ergodic sampling.
Institute of Scientific and Technical Information of China (English)
Wang Xiao-Jia; Feng Yan-Ying; Xue Hong-Bo; Zhou Zhao-Ying; Zhang Wen-Dong
2011-01-01
We demonstrate an experimental setup for the production of a beam source of cold 87Rb atoms.The atoms are extracted from a trapped cold atomic cloud in an unbalanced three-dimensional magneto-optical trap.Via a radiation pressure difference generated by a specially designed leak tunnel along one trapping laser beam,the atoms are pushed out continuously with low velocities and a high flux.The most-probable velocity in the beam is varied from 9 m/s to 19 m/s by varying the detuning of the trapping laser beams in the magneto-optical trap and the flux can be tuned up to 4× 109 s-1 by increasing the intensity of the trapping beams.We also present a simple model for describing the dependence of the beam performance on the magneto-optical trap trapping laser intensity and the detuning.
Tractor beams in the Rayleigh limit
Yevick, Aaron; Ruffner, David B.; Grier, David G.
2016-04-01
A tractor beam is a traveling wave that transports illuminated objects back to its source, opposite to the wave's direction of propagation, along its entire length. The requisite retrograde force arises when an object scatters the wave's momentum density downstream into the direction of propagation and then recoils upstream by conservation of momentum. Achieving this condition imposes constraints on the structure of the wave, which we elucidate in the Rayleigh limit, when the wavelength exceeds the size of the object. Continuously propagation-invariant modes such as Bessel beams do not satisfy these conditions at dipole order in the multipole expansion and so cannot serve as general-purpose long-ranged tractor beams. Modes with discrete propagation invariance, however, can act as first-order tractor beams. We demonstrate this by introducing a class of minimal solenoidal waves together with a set of design criteria that distinguish tractor beams that pull objects from repulsor beams that push them.
Electron beam treatment of industrial wastewater
International Nuclear Information System (INIS)
For industrial wastewater with low impurity levels such as contaminated ground water, cleaning water and etc., purification only with electron beam is possible, but it should be managed carefully with reducing required irradiation doses as low as possible. Also for industrial wastewater with high impurity levels such as dyeing wastewater, leachate and etc., purification only with electron beam requires high amount of doses and far beyond economies. Electron beam treatment combined with conventional purification methods such as coagulation, biological treatment, etc. is suitable for reduction of non-biodegradable impurities in wastewater and will extend the application area of electron beam. A pilot plant with electron beam for treating 1,000 m3/day of wastewater from dyeing industries has constructed and operated continuously since Oct 1998. Electron beam irradiation instead of chemical treatment shows much improvement in removing impurities and increases the efficiency of biological treatment. Actual plant is under consideration based upon the experimental results. (author)
Uniform trigonometric polynomial B-spline curves
Institute of Scientific and Technical Information of China (English)
吕勇刚; 汪国昭; 杨勋年
2002-01-01
This paper presents a new kind of uniform spline curve, named trigonometric polynomialB-splines, over space Ω = span{sint, cost, tk-3,tk-4,…,t,1} of which k is an arbitrary integerlarger than or equal to 3. We show that trigonometric polynomial B-spline curves have many similarV properties to traditional B-splines. Based on the explicit representation of the curve we have also presented the subdivision formulae for this new kind of curve. Since the new spline can include both polynomial curves and trigonometric curves as special cases without rational form, it can be used as an efficient new model for geometric design in the fields of CAD/CAM.
Magnetic Propeller for Uniform Magnetic Field Levitation
Krinker, Mark
2008-01-01
Three new approaches to generating thrust in uniform magnetic fields are proposed. The first direction is based on employing Lorentz force acting on partial magnetically shielded 8-shaped loop with current in external magnetic field, whereby a net force rather than a torque origins. Another approach, called a Virtual Wire System, is based on creating a magnetic field having an energetic symmetry (a virtual wire), with further superposition of external field. The external field breaks the symmetry causing origination of a net force. Unlike a wire with current, having radial energetic symmetry, the symmetry of the Virtual Wire System is closer to an axial wire. The third approach refers to the first two. It is based on creation of developed surface system, comprising the elements of the first two types. The developed surface approach is a way to drastically increase a thrust-to-weight ratio. The conducted experiments have confirmed feasibility of the proposed approaches.
Frames of most uniform Hubble flow
Kraljic, David
2016-01-01
It has been observed that the locally measured Hubble parameter converges quickest to the background value and the dipole structure of the velocity field is smallest in the reference frame of the Local Group of galaxies. We study the statistical properties of Lorentz boosts with respect to the Cosmic Microwave Background frame which make the Hubble flow look most uniform around a particular observer. We use a very large N-Body simulation to extract the dependence of the boost velocities on the local environment such as underdensities, overdensities, and bulk flows. We find that the observation is not unexpected if we are located in an underdensity, which is indeed the case for our position in the universe. The amplitude of the measured boost velocity for our location is consistent with the expectation in the standard cosmology.
Designing divertor targets for uniform power load
Dekeyser, W.; Reiter, D.; Baelmans, M.
2015-08-01
Divertor design for next step fusion reactors heavily relies on 2D edge plasma modeling with codes as e.g. B2-EIRENE. While these codes are typically used in a design-by-analysis approach, in previous work we have shown that divertor design can alternatively be posed as a mathematical optimization problem, and solved very efficiently using adjoint methods adapted from computational aerodynamics. This approach has been applied successfully to divertor target shape design for more uniform power load. In this paper, the concept is further extended to include all contributions to the target power load, with particular focus on radiation. In a simplified test problem, we show the potential benefits of fully including the radiation load in the design cycle as compared to only assessing this load in a post-processing step.
Enhanced coherent Raman emission from uniform plasmas
International Nuclear Information System (INIS)
A mechanism for the coherent emission of radio and microwaves from a warm uniform plasma is proposed. The output power from this mechanism appears to have the characteristics of a classical parametric amplification process. An earlier kinetic theory model for radiation by the scattering of plasma waves in a homogeneous plasma is revamped and modified to incorporate the dominant role of longitudinal Rayleigh scattered waves which stimulate the emission of transverse combination radiation (sum and difference of impressed and natural frequencies) by the resonant Raman scattering process in the plasma. This results in intense radio or microwave radiation at approximately twice the plasma frequency, the intensity depending upon plasma parameters. This intensity, its angular pattern, and the threshold condition for its enhanced emission are calculated. Comparisons of the computed results with the laboratory observation of the radiation output from dc discharges in argon gas, and from a helium theta-pinch plasma are made. Both qualitative and quantitative agreement are found
Non-Uniformity and Generalised Sacks Splitting
Institute of Scientific and Technical Information of China (English)
COOPER S.Barry; LI Ang Sheng
2002-01-01
We show that there do not exist computable functions f1(e, i), f2 (e, i), g1(e, i), g2(e, i) such that for all e, i ∈ω,(1) (Wf1(e,i) - Wf2(e,i)) ≤T (We - Wi);(2) (Wg1(e,i) - Wg2(e,i))≤T (We - Wi);(3) (We - Wi) ≤T (Wf1(e,i) - Wf2(e,i)) (Wg1(e,i) - Wg2(e,i));(4) (We - Wi) T (Wf1(e,i) - Wf2(e,i)) unless (We - Wi) ≤T ; and (5) (We - Wi) T (Wg1(e,i) - Wg2(e,i)) unless (We - Wi) ≤T .It follows that the splitting theorems of Sacks and Cooper cannot be combined uniformly.
Institute of Scientific and Technical Information of China (English)
王兴国; 朱坤佳; 郑宇宙; 郑丹丹; 小室雅人
2015-01-01
The flexural properties of four continuous reinforced concrete(RC)beams strengthened with near-surface mounted(NSM)mixing fiber reinforced polymer(FRP)tendons were studied by static test.The influence factors of bearing capacities of test beams were analyzed by finite element analysis(FEA)software,such as strength of concrete,initial load,elastic modulus and content of FRP tendons.Analysis result indicates that the reinforcement effect without debond between FRP tendons and concrete is significant.Compared with unstrengthened RC beam,the yield load and ultimate load of strengthened RC beam can increase by 31% and 56% respectively. When concrete strength,elastic modulus and content of FRP tendons increase,the yield load and ultimate load can increase by 38% and 17% respectively.When initial load increases,the yield load and ultimate load can decrease by 6% and 24% respectively.For test RC beams,the mean ratio of simulation and test values for the yield load is 0.969,0.962 for the ultimate load,1.104 for the midspan yield deflection,1.024 for the midspan destructive deflection,and the trends of simulation load-deflection curves are basically consistent with test curves,so FEA result is in good agreement with test result,and FEA can accurately simulate the mechanical properties of test beam.4 tabs,18 figs,22 refs.%通过4根表层内嵌入不同 FRP 筋加固连续梁试件的静载试验，研究了试验梁的弯曲性能，借助通用有限元分析软件分析了影响试验梁承载力的混凝土强度、初始荷载、FRP 筋弹性模量与配纤率等因素。分析结果表明：FRP 筋与混凝土之间未发生剥离破坏，加固效果显著；与未加固梁相比，加固梁屈服荷载与极限荷载提高幅度分别可达31％、56％；随着混凝土强度、FRP 筋弹性模量与含纤率的提高，加固梁屈服荷载与极限荷载提高幅度分别可达38％、17％；随着初始荷载的增大，加固梁屈服荷载与极限
Reflector Design Method for Rotational Uniform Illuminance System with LED
Institute of Scientific and Technical Information of China (English)
ZHANG Qi-hui; WANG Hong; JI Ling-ling
2009-01-01
Based on nonimaging design method,uniform illuminance systems with LED source were developed to create a uniform illuminated circular region with a desired size in a screen at a prescribed place.By using ray-tracing software based on Monte-Carlo method,the simulation results show that in the illuminated region the luminous uniformity is higher than 90%.
Beyond Fashion Patrol: School Uniforms in the Middle Grades.
Kommer, David
1999-01-01
Discusses the benefits of school uniforms in fulfilling the educational objectives of middle school reform. Considers the role of uniforms in establishing student affiliation with the school and in adolescent development. Describes the development of a uniform program and notes issues of cost and legality. (JPB)
A progressively reduced pretension method to fabricate Bradbury-Nielsen gates with uniform tension
Ni, Kai; Guo, Jingran; Yu, Zhou; Cao, Like; Yu, Quan; Qian, Xiang; Wang, Xiaohao
2015-11-01
A Bradbury-Nielsen gate (BNG) is often used to modulate ion beams. It consists of two interleaved and electrically isolated sets of wires with uniform tension, which ideally keep parallel, equidistant, and coplanar over a wide temperature range, making the BNG reliable and robust. We have previously analyzed the non-uniformity problem of wire tensions with sequentially winding method and developed a template-based transfer method to solve this problem. In this paper, we introduced a progressively reduced pretension method, which allows directly and sequentially fixing wires onto the substrate without using a template. Theoretical analysis shows that by applying proper pretension to each wire when fixing it, the final wire tensions of all wires can be uniform. The algorithm and flowchart to calculate the pretension sequence are given, and the fabrication process is introduced in detail. Pretensions are generated by weight combination with a weaving device. A BNG with stainless steel wire and a printed circuit board substrate is constructed with this method. The non-uniformity of the final wire tensions is less than 2.5% in theory. The BNG is successfully employed in our ion mobility spectrometer, and the measured resolution is 33.5 at a gate opening time of 350 μs. Compared to the template-based method, this method is simpler, faster, and more flexible with comparable production quality when manufacturing BNGs with different configurations.