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121.
The asymptotic behavior of state-constrained semilinear optimal control problems for distributed-parameter systems with variable
compact control zones is investigated. We derive conditions under which the limiting problems can be made explicit.
We gratefully acknowledge the support of the DAAD. The paper was prepared during the visit of the first author at the Institute
of Applied Mathematics II, University Erlangen-Nuremberg in 2003. 相似文献
122.
The performance of three-colour HgCdTe photovoltaic heterostructure detector is examined theoretically. In comparison with
two-colour detectors with two back-to-back junctions, three-colour structure contains an absorber of intermediate wavelength
placed between two junctions and electronic barriers are used to isolate this intermediate region. This structure was first
proposed by British workers.
Three-detector structures with different localizations of separating barriers are analyzed. The calculation results are presented
in the form of spatial distributions of bandgap energy and quantum efficiency.
Enhanced original computer programs are applied to solve the system of non-linear continuity equations for carriers and Poisson
equations. In addition, the numerical analysis includes the dependence of absorption coefficient on Burstein effect as well
as interference effects in heterostructure with metallic electrical contacts.
It is shown that the performance of the detector is critically dependent on the barrier’s doping level and position in relation
to the junction. This behaviour is serious disadvantage of the considered three-colour detector. A small shift of the barrier
location and doping level causes serious changes in spectral responsivity. 相似文献
123.
本文用本征通道量子亏损理论方法(EQDT方法)计算了氖等电子序列2p^5nl(l=s,d)系列的高激发态结构。得到基本结构参量(EQDT参量)随净电荷数Zc增大的变化规律,并从静电相互作用下自旋-轨道相互作用之间的竞争角度给出确切的物理解释。以NeI为实例,给出其高激发态结构的具体数值结果。 相似文献
124.
Some functions defined on the set of integer triangular matrices and their modifications are considered. These functions are analogs of the classical determinant and permanent functions and provide a powerful apparatus for studying sequences generated by linear recursive equations. Modifications of these functions are used to solve the problem about trajectories on Ferre diagrams and to establish new combinatorial identities. 相似文献
125.
G.I. Japaridze S. Sarkar 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(2):139-144
A one-dimensional model of interacting electrons with on-site U, nearest-neighbor V, and pair-hopping interaction W is studied at half-filling using the continuum limit field theory approach. The ground state phase diagram is obtained for
a wide range of coupling constants. In addition to the insulating spin-density wave (SDW) and charge-density wave (CDW) phases
for large U and V, respectively, we identify a bond-charge-density-wave (BCDW) phase W < 0, | U - 2V| < | 2W| and a bond-spin-density-wave (BSDW) for W > 0, | U - 2V| < W. The possibility of bond-located ordering results from the site-off-diagonal nature of the pair-hopping term and is a special
feature of the half-filled band case. The BCDW phase corresponding to an enhanced Peierls instability in the system. The BdSDW
is an unconventional insulating magnetic phase, characterized by a gapless spin excitation spectrum and a staggered magnetization
located on bonds between sites. The general ground state phase diagram including insulating, metallic, and superconducting
phases is discussed. A transition to the η-superconducting phase at | U - 2V| ≪ 2t?W is briefly discussed.
Received 20 February 2002 / Received in final form 11 April 2002 Published online 19 July 2002 相似文献
126.
S. Ramasubramanian 《Applied Mathematics and Optimization》2007,56(3):312-342
We consider a network of d companies (insurance companies, for example) operating under a treaty to diversify risk. Internal and external borrowing
are allowed to avert ruin of any member of the network. The amount borrowed to prevent ruin is viewed upon as control. Repayment
of these loans entails a control cost in addition to the usual costs. Each company tries to minimize its repayment liability.
This leads to a d -person differential game with state space constraints. If the companies are also in possible competition a Nash equilibrium
is sought. Otherwise a utopian equilibrium is more appropriate. The corresponding systems of HJB equations and boundary conditions
are derived. In the case of Nash equilibrium, the Hamiltonian can be discontinuous; there are d interlinked control problems with state constraints; each value function is a constrained viscosity solution to the appropriate
discontinuous HJB equation. Uniqueness does not hold in general in this case. In the case of utopian equilibrium, each value
function turns out to be the unique constrained viscosity solution to the appropriate HJB equation. Connection with Skorokhod
problem is briefly discussed. 相似文献
127.
D. Braun D. Yu P. R. Kohl X. Gao L. N. Andradi E. Manger G. P. Hellmann 《Journal of Polymer Science.Polymer Physics》1992,30(6):577-586
The miscibility of copolymers AxB1?x and AyB1?y, derived from the same monomer pair (A, B) but differing in composition, was studied. The systems (A, B) were (S, MMA), (BMA, MMA), (S, BMA), and (CIS, BMA) (S: styrene, CIS: p-chlorostyrene, MMA: methylmethacrylate, BMA: n-butylmethacrylate). Miscibility diagrams were recorded, at low and high temperatures, using cast films and dry films. All blend systems feature hightemperature miscibility gaps. Unusual effects of the compositions x and y on miscibility in blends AxB1?x/AyB1?y were observed. The classical prediction that miscibility should depend only on the composition difference |x – y| usually is too simple. It appears necessary to consider dyad interactions. 相似文献
128.
Ngc-Minh Lê 《Computational Geometry》1997,8(6):279-298
We introduce the simple abstract Voronoi diagram in 3-space as an abstraction of the usual Voronoi diagram. We show that the 3-dimensional simple abstract Voronoi diagram of n sites can be computed in O(n2) expected time using O(n2) expected space by a randomized algorithm. The algorithm is based on the randomized incremental construction technique of Clarkson and Shor (1989). We apply the algorithm to some concrete types of such diagrams: power diagrams, diagrams under ellipsoid convex distance functions, and diagrams under the Hausdorff distance for sites that are parallel segments all having the same length. 相似文献
129.
The electronic band structure of YbRhSn has been calculated using
the self-consistent full potential nonorthogonal local orbital minimum
basis scheme based on the density functional theory. We investigated
the electronic structure with the spin-orbit interaction and on-site
Coulomb potential for the Yb-derived 4f orbitals to obtain the correct
ground state of YbRhSn.
The exchange interaction between local f electrons and conduction
electrons play an important role in the heavy fermion characters of them.
The fully relativistic band structure scheme
shows that spin-orbit coupling splits the 4f states
into two manifolds, the 4f7/2 and the 4f5/2 multiplet. 相似文献
130.
A. R. Usha Devi R. Prabhu M. S. Uma 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):133-138
Production and analysis of non-Gaussian radiation fields has evinced a lot of attention recently.
Simplest way of generating such non-Gaussians is through adding (subtracting) photons to
Gaussian fields.
Interestingly, when photons are added to classical Gaussian fields, the resulting states exhibit
non-classicality.
Two important classical Gaussian radiation fields are coherent and thermal states. Here, we
study the non-classical features of
such states when photons are added to them. Non-classicality of these states shows up in the
negativity of the
Wigner function. We also work out the entanglement potential, a recently proposed measure
of non-classicality for these states. Our analysis reveals that photon added coherent states are
non-classical for all seed beam intensities; their non-classicality increases with the addition
of more number of photons. Thermal state exhibits non-classicality at all temperatures, when a
photon is added; lower the temperature, higher is their non-classicality. 相似文献