大孔径高频阵超高指向性测量的子阵分解方法

猎雷声呐这类小目标声呐的高频阵,波束极窄,通常在0.1°～0.2°范围,远场距离很远,约在三四百米以上.在常规球面波声场条件下测量指向性难以实施,近距离测量又不符合远场条件.本文将阵分成若干子阵,子阵的波束宽,远场距离近,可以先在近距离测量各子阵的复数指向性,然后推算总阵的指向性.测量是在邻近区以内的准球面波声场进行的,实验结果很好地验证了所提出的原理和方法.

Significant contributions of the petroleum industry to volatile organic compounds and ozone pollution:Insights from year-long observations in the Yellow River Delta

The petroleum industry is a significant source of anthropogenic volatile organic compounds(VOCs),but up to now,its exact impact on urban VOCs and ozone(O_(3))remains unclear.This study conducted year-long VOC ob-servations in Dongying,China,a petroleum industrial region.The VOCs from the petroleum industry(oil and gas volatilization and petrochemical production)were identified by employing the positive matrix factorization model,and their contribution to O_(3) formation was quantitatively evaluated using an observation-based chemical box model.The observed annual average concentration of VOCs was 68.6±63.5 ppbv,with a maximum daily av-erage of 335.3 ppbv.The petroleum industry accounted for 66.5%of total VOCs,contributing 54.9%from oil and gas evaporation and 11.6%from petrochemical production.Model results indicated that VOCs from the petroleum industry contributed to 31%of net O_(3) production,with 21.3%and 34.2%contributions to HO_(2)+NO and RO_(2)+NO pathways,respectively.The larger impact on the RO_(2) pathway is primarily due to the fact that OH+VOCs ac-count for 86.9%of the primary source of RO_(2).This study highlights the critical role of controlling VOCs from the petroleum industry in urban O_(3) pollution,especially those from previously overlooked low-reactivity alkanes.

波束域Root-MUSIC算法的进一步降阶处理

研究了波束域降阶Root-MUSIC算法,在子阵分解降阶的基础上,进一步将多项式的求根阶次降到与源数目相同,提出了求解降阶多项式的方法。该方法最大程度地减少了求根多项式的阶次和求解多项式的次数,并保持了Root-MUSIC算法的优良性能。显著降低运算量是其最大优点,仿真结果验证了降阶算法的有效性,并比较了不同阶次波束域Root-MUSIC算法的估计性能。

Realization of Two-Qutrit Quantum Gates with Control Pulses

We investigate the realization of 2-qutrit logic gate in a bipartite 3-level system with qusi-Ising interaction. On the basis of Caftan decomposition of matrices, the unitary matrices of 2-qutrit are factorized into products of a series of realizable matrices. It is equivalent to exerting a certain control field on the system, and the control goal is usually gained by a sequence of control pulses. The general discussion on the realization of 2-qutrit logic gate is made first, and then the realization of the ternary SWAP gate and the ternary √SWAP gate are discussed specifically, and the sequences of control pulses and drift processes implementing these gates are given.

A SUBARRAY-SYNTHESIS BASED 2D DOA ESTIMATION METHOD

In some satellite communications, we need to perform Direction Of Arrival (DOA) angle estima- tion under the restriction that the number of receivers is less than that of the array elements in an array antenna. To solve the conundrum, a method named subarray-synthesis-based Two-Dimensional DOA (2D DOA) angle estimation is proposed. In the method, firstly, the array antenna is divided into a series of subarray antennas based on the total number of receivers; secondly, the subarray antennas’ output covariance matrices are esti- mated; thirdly, an equivalent covariance matrix is synthesized based on the subarray output covariance matri- ces; then 2D DOA estimation is performed. Monte Carlo simulations showed that the estimation method is ef- fective.

Quantum Mechanical Image of Matrices' LDU Decomposition

For classical transformation （q1,q2） → （Aq1 ＋ Bq2, Cq1 ＋ Dq2）, where AD - CB ≠ 1, we find its quantum mechanical image by using LDU decomposition of the matrix （A B C D ）. The explicit operators L, D, and U axe derived and their physical meaning is revealed, this also provides a new way for disentangling some exponential operators.

Note on Implementation of Three-Qubit SWAP Gate

In this paper, the synthesis and implementation of three-qubit SWAP gate is discussed. The three-qubit SWAP gate can be decomposed into product of 2 two-qubit SWAP gates, and it can be realized by 6 CNOT gates. Research illustrated that although the result is very simple, the current methods of matrix decomposition for multi-qubit gate can not get that. Then the implementation of three-qubit SWAP gate in the three spin system with Ising interaction is investigated and the sequence of control pulse and drift process to implement the gate is given. It needs 23 control pulses and 12 drift processes. Since the interaction can not be switched on and off at will, the realization of three-qubit SWAP gate in specific quantum system also can not simply come down to 2 two-qubit SWAP gates.

Direct visualization of the charge transfer in conjugated polymers

Ion-induced charge-transfer states in conjugated polyelectrolytes were experimentally investigated by Justin M.Hodgkiss and his co-workers [J Am Chem Soc,2009,131(25):8913].In this work,charged and neutral conjugated polyelectrolytes were further studied with quantum chemistry methods.The calculation result shows that the absorption spectra are roughly in visible and ultraviolet light regions,and the two absorption peaks are located in the wavelength span 300-400 nm for charged polyelectrolytes.However,in neutral conjugated polyelectrolytes,the peaks of the absorption spectra showed a blue shift compared with those of the charged polyelectrolytes.Charge transfer (CT) properties of the studied compounds were also investigated with both the three-dimensional real-space analysis method of transition and charge difference densities,and the two-dimensional real-space analysis method of transition density matrices based on the simulated absorption spectra.The calculation results revealed the charge transfer in conjugated polyelectrolytes on the excitation states.

Anisotropic Hardy-Lorentz spaces and their applications

Let p ∈(0, 1], q ∈(0, ∞] and A be a general expansive matrix on Rn. We introduce the anisotropic Hardy-Lorentz space H^(p,q)_A(R^n) associated with A via the non-tangential grand maximal function and then establish its various real-variable characterizations in terms of the atomic and the molecular decompositions, the radial and the non-tangential maximal functions, and the finite atomic decompositions. All these characterizations except the ∞-atomic characterization are new even for the classical isotropic Hardy-Lorentz spaces on Rn.As applications, we first prove that Hp,q A(Rn) is an intermediate space between H^(p1,q1)_A(Rn) and H^(p2,q2)_A(R^n) with 0 < p1 < p < p2 < ∞ and q1, q, q2 ∈(0, ∞], and also between H^(p,q1)_A(Rn) and H^(p,q2)_A(R^n) with p ∈(0, ∞)and 0 < q1 < q < q2 ∞ in the real method of interpolation. We then establish a criterion on the boundedness of sublinear operators from H^(p,q)_A(R^n) into a quasi-Banach space; moreover, we obtain the boundedness of δ-type Calder′on-Zygmund operators from H^(p,∞)_A(R^n) to the weak Lebesgue space L^(p,∞)(R^n)(or to H^p_A(R^n)) in the ln λcritical case, from H^(p,q)_A(R^n) to L^(p,q)(R^n)(or to H^(p,q)_A(R^n)) with δ∈(0,(lnλ)/(ln b)], p ∈(1/(1+,δ),1] and q ∈(0, ∞], as well as the boundedness of some Calderon-Zygmund operators from H^(p,q)_A(R^n) to L^(p,∞)(R^n), where b := | det A|,λ_:= min{|λ| : λ∈σ(A)} and σ(A) denotes the set of all eigenvalues of A.

A New Solution to the Hirota–Satsuma Coupled KdV Equations by the Dressing Method

The Hirota-Satsuma coupled KdV equations associated 2 x 2 matrix spectral problem is discussed by the dressing method, which is based on the factorization of integral operator on a line into a product of two Volterra integral operators. A new solution is obtained by choosing special kernel of integral operator.

Weighted Polar Decomposition

In this paper,a new matrix decomposition called the weighted polar decomposition is considered.Two uniqueness theorems of weighted polar decomposition are presented,and the best approximation property of weighted unitary polar factor and perturbation bounds for weighted polar decomposition are also studied.

DECOMPOSITION OF MATRICES INTO COMMUTATORS OF REFLECTIONS

Let F be a field and let resA = rank(A - I) for any A in GLnF. We prove that every matrix in SLnF is a product of at most [resA/2] + 2 commutators of reflections for n 】 2 except for n - 2 and F = F2.

ADJOINT SYMMETRY CONSTRAINTS OF MULTICOMPONENT AKNS EQUATIONS

A soliton hierarchy of multicomponent AKNS equations is generated from an arbitraryorder matrix spectral problem, along with its bi-Hamiltonian formulation. Adjoint symmetry constraints are presented to manipulate binary nonlinearization for the associated arbitrary order matrix spectral problem. The resulting spatial and temporal constrained flows are shown to provide integrable decompositions of the multicomponent AKNS equations.

Quasi Three-Body Decay of D Meson

The aim of this work is to provide a phenomenological analysis of the contribution of D^0 meson to K*(892)~0π^+π^-(K*(892)~0-→π^+K^-), K^-π^+ω(ω-→π^+π^-π~0) and K^-π^+?(?(1020)-→ K^+K^-) quasi-three-body decays. The analysis of mentioned multi-body decays is such as to factorize into the three-body decay and several channels observed. Hadronic three-body decays receive both resonant and non-resonant contribution. Based on the factorization method, there are tree and emission annihilation diagrams for these decay modes. In the case of D^0 to vector pseudoscalar states appeared in factored terms, the matrix elements of the vector and axial vector currents between the D^0 and PV mesons can be computed by using D^(*+)pole. Considering the non-resonant and resonant amplitude in our computation,the theoretical values of the branching ratio are(9.78 ± 0.46) × 10^(-3),(2.74 ± 0.17) × 10^(-2), and(3.53 ± 0.23) × 10^(-5), while the experimental results of them are(9.9 ±2.3) × 10^(-3),(2.7 ± 0.5) × 10^(-2), and(4 ± 1.7) × 10^(-5) respectively. Comparing computational analysis values with experimental values show that our results are in approximately agreement with them.

Freeness and matrix decompositions

If a semicircular element and the diagonal subalgebra of a matrix algebra are free in a finite von Neumann algebra （with respect to a normal trace）, then, up to the conjugation by a diagonal unitary element, all entries of the semicircular element are uniquely determined in the sense of （joint） distribution. Suppose a selfadjoint element is free with the diagonal subalgebra. Then, in the matrix decomposition of the selfa^tjoint element, any two entries cannot be free with each other unless the selfadjoint element is semicircular. We also define a ＂matricial distance＂ between two elements and show that such distance for two free semicircular elements in a finite von Neumann algebra is nonzero and independent of the properties of the von Neumann algebra.