Coupling effect of solenoid in CSRm

The principle of particle coupling between horizontal and vertical directions in solenoid is presented. Further more, the method of decoupling can be obtained by using the coupling dynamic equations. 5000 particles are tracked under three conditions: CSRm doesn't contain solenoids, contains main solenoid and toroids, contains compensating solenoids. The results of the particle trace calculations show that the particles coupling between horizontal and vertical is very serious because of the existence of solenoids, and lot's of particals are lost. Another two solenoids which locate in the fit place can be used to decrease the coupling intensation. The method is proved to be useful by the trace calculations.

CSRm 束流横向耦合研究

在环形加速器中，横向耦合表现为粒子在径向和轴向两方向振荡间的能量交换。耦合效应会对束流品质产生一系列的弊端影响，所以束流耦合的研究成为加速器研究中的一个必要的课题。 本论文首先对兰州重离子加速器冷却储存环（HIRFL-CSR）的结构作了简单说明，交代了电子冷却装置的位置及组成，说明了螺线管场在装置中的作用及其耦合效应，继而提出研究横向耦合对HIRFL-CSR主环的重要性和必要性。 接着本论文对横向耦合运动的基础理论作了推导和描述，提出以传输矩阵研究束流相空间运动的方法，分析了横向耦合对束流发射度的影响及横向耦合的匹配条件，并详细分析了束流的径向和轴向耦合振荡在和、差共振时的稳定性情况。 最后，根据储存环主环（CSRm）的实际情况，模拟计算了CSRm中多种耦合源在不同工作点时的束流稳定情况，比较了磁铁的纵向角安装误差与螺线管场对束流耦合效应的大小；并且模拟了冷却段螺线管场对束流发射度和动力学孔径的横向耦合效应，通过模拟提出了合适的耦合补偿方案，这样以减少由于耦合造成的束流损失

Isolating CP-violating gamma ZZ coupling in e(+)e(-) -> gamma Z with transverse beam polarizations

We revisit the process e(+)e(-) -> gamma Z at the ILC with transverse beam polarization in the presence of anomalous CP- violating gamma ZZ coupling lambda(1) and gamma gamma Z coupling lambda(2). We point out that if the final- state spins are resolved, then it becomes possible to fingerprint the anomalous coupling Re lambda(1). 90% confidence level limit on Re lambda(1) achievable at ILC with center- of- mass energy of 500 GeVor 800 GeV with realistic initial beam polarization and integrated luminosity is of the order of few times of 10(-2) when the helicity of Z is used and 10(-3) when the helicity of gamma is used. The resulting corrections at quadratic order to the cross section and its influence on these limits are also evaluated and are shown to be small. The benefits of such polarization programmes at the ILC are compared and contrasted for the process at hand. We also discuss possible methods by which one can isolate events with a definite helicity for one of the final- state particles.

Rashba spin-orbit coupling in InSb nanowires under transverse electric field

We investigate the Rashba spin-orbit coupling brought by transverse electric field in InSb nanowires. In small k(z) (k(z) is the wave vector along the wire direction) range, the Rashba spin-orbit splitting energy has a linear relationship with k(z), so we can define a Rashba coefficient similarly to the quantum well case. We deduce some empirical formulas of the spin-orbit splitting energy and Rashba coefficient, and compare them with the effective-mass calculating results. It is interesting to find that the Rashba spin-orbit splitting energy decreases as k(z) increases when k(z) is large due to the k(z)-quadratic term in the band energy. The Rashba coefficient increases with increasing electric field, and shows a saturating trend when the electric field is large. As the radius increases, the Rashba coefficient increases at first, then decreases. The effects of magnetic fields along different directions are discussed. The case where the magnetic field is along the wire direction or the electric field direction are similar. The spin state in an energy band changes smoothly as k(z) changes. The case where the magnetic field is perpendicular to the wire direction and the electric field direction is quite different from the above two cases, the k(z)-positive and negative parts of the energy bands are not symmetrical, and the energy bands with different spins cross at a k(z)-nonzero point, where the spin splitting energy and the effective g factor are zero.

Influence of transverse interdot coupling on transport properties of an Aharonov-Bohm structure composed by two dots and two reservoirs

We derive the modified rate equations for an Aharonov-Bohm (AB) ring with two transversely coupled quantum dots (QD's) embedded in two arms in the presence of a magnetic field. We find that the interdot coupling between the two QD's can cause a temporal oscillation in electron occupation at the initial stage of the quantum dynamics, while the source-drain current decays monotonically to a stationary value. On the other hand, the interdot coupling equivalently divides the AB ring into two coupled subrings. That also destroys the normal AB oscillations with a period of 2pi, and generates new and complex periodic oscillations with their periods varying in a linear manner as the ratio between two magnetic fluxes (each penetrates one AB subring) increases. Furthermore, the interference between two subrings is also evident from the observation of the perturbed fundamental AB oscillation.

Complete nonlinear theory of longitudinal-to-transverse dust lattice mode coupling in a single-layer dusty plasma crystal

A comprehensive nonlinear model is put forward for coupled longitudinal to transverse displacements in a horizontal dust mono-layer, levitated under the combined influence of gravity and an electric and/or magnetic sheath field. A set of coupled nonlinear evolution equations are obtained in a discrete description, and a pair of coupled (Boussinesq-like) PDEs are obtained in the continuum approximation. Finally, the amplitude modulation of the coupled modes is discussed, pointing out the importance of the coupling. All these results are generic, i.e. valid for any assumed form of the inter-grain interaction potential U and the sheath potential Phi.

Polarisation mode coupling of excessively tilted fibre Bragg gratings with directional transverse loading

We report a distinctive polarisation mode coupling behaviour of tilted fibre Bragg gratings (TFBGs) with tilted angle exceeding 45°. The ex-45° TFBGs exhibit pronounced polarisation mode splitting resulted from grating structure asymmetry induced birefringence. We have studied and analysed the property of ex-45° TFBGs under transverse load applied to their equivalent fast- and slow-axis. The results show that the coupling between the orthogonally polarised modes takes place only when the load is applied to its fast-axis, giving a prominent directional loading response. This transverse load related polarisation property may be exploitable for implementation of optical fibre vector sensors capable of measuring the magnitude and orientation of the applied transverse load.

Polarisation mode coupling of excessively tilted fibre Bragg gratings with directional transverse loading

We report a distinctive polarisation mode coupling behaviour of tilted fibre Bragg gratings (TFBGs) with tilted angle exceeding 45°. The ex-45° TFBGs exhibit pronounced polarisation mode splitting resulted from grating structure asymmetry induced birefringence. We have studied and analysed the property of ex-45° TFBGs under transverse load applied to their equivalent fast- and slow-axis. The results show that the coupling between the orthogonally polarised modes takes place only when the load is applied to its fast-axis, giving a prominent directional loading response. This transverse load related polarisation property may be exploitable for implementation of optical fibre vector sensors capable of measuring the magnitude and orientation of the applied transverse load.

NMR relaxation behavior and quadrupole coupling constants of 39K and 23Na ions in glycerol. Comparisons with 39K tissue data

The quadrupole coupling constants (qcc) for39K and23Na ions in glycerol have been calculated from linewidths measured as a function of temperature (which in turn results in changes in solution viscosity). The qcc of39K in glycerol is found to be 1.7 MHz, and that of23Na is 1.6 MHz. The relaxation behavior of39K and23Na ions in glycerol shows magnetic field and temperature dependence consistent with the equations for transverse relaxation more commonly used to describe the reorientation of nuclei in a molecular framework with intramolecular field gradients. It is shown, however, that τc is not simply proportional to the ratio of viscosity/temperature (ηT). The 39K qcc in glycerol and the value of 1.3 MHz estimated for this nucleus in aqueous solution are much greater than values of 0.075 to 0.12 MHz calculated from T2 measurements of39K in freshly excised rat tissues. This indicates that, in biological samples, processes such as exchange of potassium between intracellular compartments or diffusion of ions through locally ordered regions play a significant role in determining the effective quadrupole coupling constant and correlation time governing39K relaxation. T1 and T2 measurements of rat muscle at two magnetic fields also indicate that a more complex correlation function may be required to describe the relaxation of39K in tissue. Similar results and conclusions are found for23Na.

Non-linear refined finite element elastic analysis of steel frames with generalized transverse member loads

In the finite element modelling of steel frames, external loads usually act along the members rather than at the nodes only. Conventionally, when a member is subjected to these transverse loads, they are converted to nodal forces which act at the ends of the elements into which the member is discretised by either lumping or consistent nodal load approaches. For a contemporary geometrically non-linear analysis in which the axial force in the member is large, accurate solutions are achieved by discretising the member into many elements, which can produce unfavourable consequences on the efficacy of the method for analysing large steel frames. Herein, a numerical technique to include the transverse loading in the non-linear stiffness formulation for a single element is proposed, and which is able to predict the structural responses of steel frames involving the effects of first-order member loads as well as the second-order coupling effect between the transverse load and the axial force in the member. This allows for a minimal discretisation of a frame for second-order analysis. For those conventional analyses which do include transverse member loading, prescribed stiffness matrices must be used for the plethora of specific loading patterns encountered. This paper shows, however, that the principle of superposition can be applied to the equilibrium condition, so that the form of the stiffness matrix remains unchanged with only the magnitude of the loading being needed to be changed in the stiffness formulation. This novelty allows for a very useful generalised stiffness formulation for a single higher-order element with arbitrary transverse loading patterns to be formulated. The results are verified using analytical stability function studies, as well as with numerical results reported by independent researchers on several simple structural frames.

Novel non-linear elastic structural analysis with generalised transverse element loads using a refined finite element

In the finite element modelling of structural frames, external loads such as wind loads, dead loads and imposed loads usually act along the elements rather than at the nodes only. Conventionally, when an element is subjected to these general transverse element loads, they are usually converted to nodal forces acting at the ends of the elements by either lumping or consistent load approaches. In addition, it is especially important for an element subjected to the first- and second-order elastic behaviour, to which the steel structure is critically prone to; in particular the thin-walled steel structures, when the stocky element section may be generally critical to the inelastic behaviour. In this sense, the accurate first- and second-order elastic displacement solutions of element load effect along an element is vitally crucial, but cannot be simulated using neither numerical nodal nor consistent load methods alone, as long as no equilibrium condition is enforced in the finite element formulation, which can inevitably impair the structural safety of the steel structure particularly. It can be therefore regarded as a unique element load method to account for the element load nonlinearly. If accurate displacement solution is targeted for simulating the first- and second-order elastic behaviour on an element on the basis of sophisticated non-linear element stiffness formulation, the numerous prescribed stiffness matrices must indispensably be used for the plethora of specific transverse element loading patterns encountered. In order to circumvent this shortcoming, the present paper proposes a numerical technique to include the transverse element loading in the non-linear stiffness formulation without numerous prescribed stiffness matrices, and which is able to predict structural responses involving the effect of first-order element loads as well as the second-order coupling effect between the transverse load and axial force in the element. This paper shows that the principle of superposition can be applied to derive the generalized stiffness formulation for element load effect, so that the form of the stiffness matrix remains unchanged with respect to the specific loading patterns, but with only the magnitude of the loading (element load coefficients) being needed to be adjusted in the stiffness formulation, and subsequently the non-linear effect on element loadings can be commensurate by updating the magnitude of element load coefficients through the non-linear solution procedures. In principle, the element loading distribution is converted into a single loading magnitude at mid-span in order to provide the initial perturbation for triggering the member bowing effect due to its transverse element loads. This approach in turn sacrifices the effect of element loading distribution except at mid-span. Therefore, it can be foreseen that the load-deflection behaviour may not be as accurate as those at mid-span, but its discrepancy is still trivial as proved. This novelty allows for a very useful generalised stiffness formulation for a single higher-order element with arbitrary transverse loading patterns to be formulated. Moreover, another significance of this paper is placed on shifting the nodal response (system analysis) to both nodal and element response (sophisticated element formulation). For the conventional finite element method, such as the cubic element, all accurate solutions can be only found at node. It means no accurate and reliable structural safety can be ensured within an element, and as a result, it hinders the engineering applications. The results of the paper are verified using analytical stability function studies, as well as with numerical results reported by independent researchers on several simple frames.

Use of transverse beam polarization to probe anomalous V V H interactions at a Linear Collider

We investigate use of transverse beam polarization in probing anomalous coupling of a Higgs boson to a pair of vector bosons, at the International Linear Collider (ILC). We consider the most general form of V V H (V = W/Z) vertex consistent with Lorentz invariance and investigate its effects on the process e(+)e(-) -> f (f) over barH, f being a light fermion. Constructing observables with definite C P and naive time reversal ((T) over tilde) transformation properties, we find that transverse beam polarization helps us to improve on the sensitivity of one part of the anomalous Z Z H Coupling that is odd under C P. Even more importantly it provides the possibility of discriminating from each other, two terms in the general Z Z H vertex, both of which are even under C P and (T) over bar. Use of transversebeam polarization when combined with information from unpolarized and linearly polarized beams therefore, allows one to have completely independent probes of all the different parts of a general ZZH vertex.

Temperature-dependent infrared reflectivity studies of multiferroic TbMnO3: Evidence for spin-phonon coupling

We have measured near normal incidence far-infrared (FIR) reflectivity spectra of a single crystal of TbMnO3 from 10 K to 300 K in the spectral range of 50 cm(-1)-700 cm(-1). Fifteen transverse optic (TO) and longitudinal optic (LO) modes are identified in the imaginary part of the dielectric function epsilon(2)(omega) and energy loss function Im(-1/epsilon(omega)), respectively. Some of the observed phonon modes show anomalous softening below the magnetic transition temperature T-N (similar to 46 K). We attribute this anomalous softening to the spin-phonon coupling caused by phonon modulation of the superexchange integral between the Mn3+ spins. The effective charge of oxygen (Z(O)) calculated using the measured LO-TO splitting increases below TN.

Instability of Coupled Longitudinal and Transverse Electromagnetic Modes of Wave‐Propagation in Bounded Streaming Plasmas

The instability of coupled longitudinal and transverse electromagnetic modes associated with long wavelengths is studied in bounded streaming plasmas. The main conclusions are as follows: (i) For long waves for which O (k 2)=0, in the absence of relative streaming motion of electrons and ions and aωp/c<0.66, the whole spectrum of harmonic waves is excited due to finite temperature and boundary effects consisting of two subseries. One of these subseries can be identified with Tonks-Dattner resonance oscillations for the electrons, and arises primarily due to the electrons with frequencies greater than the electrostatic plasma frequency corresponding to the electron density in the midplane in the undisturbed state. The other series arises primarily due to ion motion. When aωp/c>0.66, in addition to the above spectrum of harmonic waves, the system admits an infinite number of growing and decaying waves. The instability associated with these modes is found to arise due to the interaction of the waves inside the plasma with the external electromagnetic field. (ii) For modes with comparatively shorter wavelengths for which O (k3)=0, the coupling due to finite temperature sets in, and it is found that the two series of harmonic waves obtained in (i) deriving energy from the transverse modes also become unstable. Thus, for these wavelengths the system admits three sets of growing and decaying modes, first two for all values of aωp/c and the third for (aωp/c) > 0.66. (iii) The presence of streaming velocities introduces various other coupling mechanisms, and we find that even for the wavelengths for which O (k2)=0, we get three sets of growing and decaying waves. The numerical values for the growth rates show that the streaming velocities enhance the growth rates of instability significantly.