不同晶体取向下纳米压痕的多尺度模拟

采用准连续介质多尺度方法模拟面心立方金属铝单晶薄膜的纳米压痕变形过程.对薄膜分别采用三种不同的晶体取向(分别为x［1 1 1］,y［1 1 0］,z［1 1 2］; x［1 1 2］,y［1 1 1］,z［1 1 0］;x［1 1 0］,y［0 0 1］,x［1 1 0］),得到载荷-位移响应曲线.加载过程中,对晶体内部变形比较剧烈的部分画出原子图,并从微观角度分析产生剧烈变形的原 关键词： 纳米压痕 准连续介质方法 晶体取向 位错成核     

On q-Deformed $${{\mathfrak{gl}}_{\ell+1}}$$-Whittaker Function III

In this paper, we identify q-deformed \mathfrakgl_l+1{\mathfrak{gl}_{\ell+1}}-Whittaker functions with a specialization of the Macdonald polynomials. This provides a representation of q-deformed \mathfrakgl_l+1{\mathfrak{gl}_{\ell+1}}-Whittaker functions in terms of the Demazure characters of affine Lie algebra [^(\mathfrakgl)]_l+1{\widehat{\mathfrak{gl}}_{\ell+1}}. We also define a system of dual Hamiltonians for q-deformed \mathfrakgl_l+1{\mathfrak{gl}_{\ell+1}}-Toda chains and give a new integral representation for the q-deformed \mathfrakgl_l+1{\mathfrak{gl}_{\ell+1}}-Whittaker functions. Finally, we represent the q-deformed \mathfrakgl_l+1{\mathfrak{gl}_{\ell+1}}-Whittaker function as a matrix element of a quantum torus algebra.     

轴矢介子的质量和混合角

根据质量劈裂公式计算了轴矢介子多重态(1¹P₁)中底偶素的质量,然后利用粒子表上最新的实验数据,在雷吉唯象的框架下计算轴矢介子多重态中双重介子B_c1、奇异偶素(ss-bar和奇异介子K_1B的质量. 最后在介子-介子混合的框架下,计算了K_1A - K_1B混合角和轴矢介子九重态中两个同位旋标量态的混合角. 我们建议实验上在1478 MeV能量附近进一步研究轴矢介子h₁(1380)的性质,在6774 MeV能量附近寻找和研究轴矢介子B_c1(1P).本文的计算结果对于实验上寻找还没有观测到的双重介子态B_c1以及理解K_1A - K_1B混合和轴矢介子九重态的混合有一定的意义. 关键词： 介子谱 雷吉轨迹 介子-介子混合     

Coincidence theorem for the direct correlation function of hard-particle fluids

The Mayerf-function for purely hard particles of arbitrary shape satisfiesf ²(1, 2)=–f(1, 2). This relation can be introduced into the graphical expansion of the direct correlation functionc(1, 2) to obtain a graphical expression for the case of exact coincidence, in position and orientation, of two identical hard cores. The resulting expression forc(1, 1)+1 contains only graphsG fromc(1), the sum of irreducible graphs with one labeled point. Relative to its coefficient inc(1),G occurs inc(1, 1) with an additional factorR _c which is 1 for the leading graph in the expansion and of the form 2–2L(G) for all other graphs. HereL(G)=0, 1, 2,..., is a nonnegative integer. Topological analysis is used to derive an expression forL(G) in terms of the connectivity properties ofG.     

Letter: O(d + 1, d + n + 1)-Invariant Formulation of Stationary Heterotic String Theory

We present a pair of symmetric formulations of the matter sector of the stationary effective action of heterotic string theory that arises after the toroidal compactification of d dimensions. The first formulation is written in terms of a pair of matrix potentials Z ₁ and Z ₂ which exhibits a clear symmetry between them and can be used to generate new families of solutions on the basis of either Z ₁ or Z ₂; the second one is an O(d + 1, d + n + 1)-invariant formulation which is written in terms of a matrix vector W endowed with an O(d + 1, d + n + 1)-invariant scalar product which linearizes the action of the O(d + 1, d + n + 1)symmetry group on the coset space O(d + 1, d + n + 1)/[O(d + 1) × O(d + n + 1)]; this fact opens as well a simple solution-generating technique which can be applied on the basis of known solutions.     

Regarding the axial-vector mesons

The implications of the f₁(1285)-f₁(1420) mixing for the K₁(³P₁)- K₁(¹P₁) mixing angle are investigated. Based on the f₁(1285)-f₁(1420) mixing angle ∼ 50^° suggested from the analysis for a substantial body of data concerning the f₁(1420) and f₁(1285), the masses of the K₁(³P₁) and K₁(¹P₁) are determined to be ∼ 1307.35±0.63 MeV and 1370.03±9.69 MeV, respectively, which therefore suggests that the K₁(³P₁)- K₁(¹P₁) mixing angle is about ±(59.55±2.81)^°. Also, it is found that the mass of the h^′₁(¹P₁) (mostly of sˉ) state is about 1495.18±8.82 MeV. Comparison of the predicted results and the available experimental information of the h₁(1380) shows that without further confirmation on the h₁(1380), the assignment of the h₁(1380) as the sˉ member of the ¹P₁ meson nonet may be premature.     

Solvent solute interactions probed by picosecond transient Raman spectroscopy:S 1 1,4-diphenyl-1,3-butadiene in the linear alkanes

We present theS ₁ Raman spectra of 1,4-DiPhenyl-1,3-Butadiene (DPB) in a series of linear alkanes (pentane, hexane, heptane, octane, decane, and dodecane). Bands assignable to both the 1¹ B _u and 2¹ A _g states are present, suggesting that the state we are observing in solution is a mixed state with both 1¹ B _u and 2¹ A _g character. The relative intensities of several bands associated with C_oC_o stretching motions in the 2¹ A _g and 1¹ B _u states change systematically through the solvent series. The relative intensity changes reflect a changing distribution ofs-trans conformers inS ₁ DPB as the solvent is varied. We suggest that the distribution ofs-trans conformers inS ₁ DPB controls the nature of the mixing between the 2¹ A _g and 1¹ B _u states and that the distribution of conformers is controlled by the solvent viscosity. Changes in the peak position and bandwidth of the phenyl C=C stretch with delay reflect vibrational relaxation processes inS ¹ DPB. We observe anomolous behavior in pentane that we attribute to the effect of the solvent structure on the ability of DPB to exchange energy with pentane.     

Excited Even-Symmetry States of Metallocomplexes of Porphin and Its Derivatives

Based on calculations by the CNDO/S method, data on the excited molecular states of even parity of the magnesium complexes of porphin (P), tetraazaporphin (TAP), tetrabenzoporphin (TBP), and phthalocyanine (Phc) are obtained. It is only in MgP that the first excited g-state 1¹ B _2g (29,000 cm^–1) is located 300 cm^–1 higher than the B level (28,700 cm^–1). In MgTBP, the two states 1¹ B _1g (24,700 cm^–1) and 1¹ B _2g (25,500 cm^–1) are found to be near the B level (27,500 cm^–1), while the states 1¹ B _2g (25,500 cm^–1) in MgTAP and 1¹ B _2g (21,000 cm^–1) and 1¹ B _1g (23,100 cm^–1) in MgPhc are located much lower than the B level; the energy of the latter is 31,900 and 32,400 cm^–1 in MgTAP and MgPhc respectively. The results obtained are in good agreement with experimental data on two-photon absorption: in the zinc complex of tetraphenylporphin (TPhP), the g-state is detected in the region of the B level, while in ZnPhc, two bands at 20,400 and 21,700 cm^–1 show up.     

Ⅲ-Ⅴ族化合物半导体合金组分的电解液电场调制反射(EER)光谱测量

观察了一系列Ⅲ-Ⅴ族化合物半导体合金GaAs1-xPx和AlxGa1-xAs样品的电解液电场调制反射光谱(EER)与合金组分参数X的关系.在临界点能量及其相关的自旋“轨道分裂Eg0,△0,Eg1,△1的计算中,采用了”三点调整法”.按照文献给出的公式,从Eg0的值求得所有GaAs1-xPx样品的组分.由此,通过最佳拟合法碍到[Eg0+△0](x)、Eg1(x)、(Eg1+△1)(x)的经验公式均为抛物线型的.在GaP(X=1)的情形中,明确地测得△1的值约为0.19eV,这与△1:△0比值的“2/3规则”有显著的偏离.本文还说明了,对半导体合金组分的光电压法测定中常用的线性型Eg0(x)假设,有必要进行二次项修正.     

Relativistic many-body calculations of E1, E2, M1, and M2 transitions rates for the 1 s 2 l′ 2 l′ ′ – 1 s 2 2 l lines in Li-like ions

Reduced matrix elements, oscillator strengths, and transition rates are calculated for all allowed and forbidden 1s2l′ 2l′ ′ – 1s ²2l electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions in lithiumlike ions with nuclear charges ranging from Z?=?6 to 100. Relativistic many-body perturbation theory (RMBPT), including the Breit interaction, is used to evaluate retarded E1, M1, E2, and M2 matrix elements. The calculations start with a Dirac potential and include all possible 1s2l′ 2l′ ′ configurations, leading to seven odd-parity and nine even-parity states. First-order perturbation theory is used to obtain intermediate coupling coefficients. Second-order RMBPT is used to determine the matrix elements, which are evaluated for the 22, 20, 16, and 18 possible E1, M1, E2, and M2 transitions, respectively. A detailed discussion of the various contributions to the energy levels and E1, M1, E2, and M2 matrix elements is given for lithiumlike iron, Z?=?26. The transition energies used in the calculation of oscillator strengths and transition rates are evaluated using second-order RMBPT. Trends of E1, M1, E2, and M2 transition rates as functions of nuclear charge Z are shown graphically for 1s2l′ 2l′ ′ – 1s ²2l transitions.     

On Static Shells and the Buchdahl Inequality for the Spherically Symmetric Einstein-Vlasov System

In a previous work [1] matter models such that the energy density ρ ≥ 0, and the radial- and tangential pressures p ≥ 0 and q, satisfy p + q ≤ Ωρ, Ω ≥ 1, were considered in the context of Buchdahl’s inequality. It was proved that static shell solutions of the spherically symmetric Einstein equations obey a Buchdahl type inequality whenever the support of the shell, [R ₀, R ₁], R ₀ > 0, satisfies R ₁/R ₀ < 1/4. Moreover, given a sequence of solutions such that R ₁/R ₀ → 1, then the limit supremum of 2M/R ₁ was shown to be bounded by ((2Ω + 1)² − 1)/(2Ω + 1)². In this paper we show that the hypothesis that R ₁/R ₀ → 1, can be realized for Vlasov matter, by constructing a sequence of static shells of the spherically symmetric Einstein-Vlasov system with this property. We also prove that for this sequence not only the limit supremum of 2M/R ₁ is bounded, but that the limit is ((2Ω + 1)² − 1)/(2Ω + 1)² = 8/9, since Ω = 1 for Vlasov matter. Thus, static shells of Vlasov matter can have 2M/R ₁ arbitrary close to 8/9, which is interesting in view of [3], where numerical evidence is presented that 8/9 is an upper bound of 2M/R ₁ of any static solution of the spherically symmetric Einstein-Vlasov system.     

Study of anomalous lasing behavior on the twoJ=0−1 transitions in Ne-like V

We present an experimental report on the recent observation of lasing at 26.1 and 30.4 nm on the 3p ¹ S ₀–3s ³ P ₁ [termedG((0–1)] and 3p ¹ S ₀–3s ¹ P ₁ [termedE(0–1)] transitions in Ne-like V, in which the normally weakG(0–1) transition was observed to lase more strongly than theE(0–1) transition. The experiment was performed on the Asterix IV iodine laser with a prepulse 5.23 ns before the main pulse. At a target length of about 2.5 cm, it was found that, while theG(0–1) andE(0–1) lines have comparable intensities in V, theE(0–1) line dominates spectra from Mn, Cr, Ti and Sc, which have adjacent nuclear charges. It was also found that the two lasers in V also have different temporal histories and spatial distributions. This is in contrast to the LASNEX + XRASER simulation, which predicts virtually similar temporal and spatial behavior for the two transitions. On leave from: Shanghai Institute of Optics and Fine Mechanics, P.O. Box 800211, Shanghai, People's Republic of China     

Strange axial-vector mesons mixing angle

The masses of K ₁(³ P ₁) and K ₁(¹ P ₁) are considered in a nonrelativistic constituent quark model, and the absolute value of the K ₁(³ P ₁)- K ₁(¹ P ₁) mixing angle is determined to be about 59.29^°. The comparison of the theoretical predictions on the strong decay widths of K ₁(1270) and K ₁(1400) in the ³ P ₀ decay model as well as the production ratio of these two states in the τ decay between the available experimental data strongly favors that the K ₁(³ P ₁)- K ₁(¹ P ₁) mixing angle is about +59.29^°.     

带栅极纳米线冷阴极的场增强因子研究

场增强因子是体现场发射冷阴极器件性能优劣的重要参数.利用静电场理论给出了一种带栅极(normal-gated)纳米线冷阴极的场增强因子表示式β=k₁{N²·(L-d₁)²+［1/k₁+(L-d₁)］²}^1/2，且进一步分析了几何参数对场增强因子的影响.结果表明，纳米线突出栅孔的部分(L-d₁)与栅孔半径越大，则场增强因子越大；而纳米线半径越小，则场增强因子越大；当L远大于d₁时满足β∝L/r₀.其中N=N₁(k₁r₀)/N₀(k₁r₀)，N₀(k₁r₀)和N₁(k₁r₀)分别代表零阶和一阶Neumann函数，k₁=0.8936/R，R为栅孔半径，L为纳米线长度，r₀为纳米线半径，d₁表示阴极与栅极间距.     

Canonical Representations of Sp(1,n) Associated with Representations of Sp(1)

Canonical representations of Sp(1,n) associated with finite dimensional irreducible representations of Sp(1) are defined using vector-valued Berezin kernels. Their decomposition into irreducible representations is determined by decomposing the corresponding reproducing distributions in terms of positive definite trace spherical functions on Sp(1,n). The canonical representatons are also identified with the restriction to Sp(1,n) of certain maximal degenerate representations of SL(n+1,H). Received: 1 May 1998 / Accepted: 18 November 1998     

Spectroscopic study of injected electrons in solid helium

IR absorption spectra of excess electrons, selflocalized in bubbles in solid hcp⁴He and bcc³He, are measured. The pressure dependence of the 1s–1p transition energyE _1s1p can be fitted by the values, calculated using spherical rectangular well model and taking surface tension to be pressure independent. The bubble radius obtained varies smoothly from 10.7 Å at 45 atm to 9.4 Å at 100 atm, no dependence on crystalline structure as well as on isotope composition has been observed. The 1s–1p linewidth is 5–6 times smaller thanE _1s1p .The absorption cross section is estimated to be 12 Ų.     

Buffer-gas pressure broadening for the 2ν3 band of methane measured with continuous-wave cavity ring-down spectroscopy

Buffer-gas pressure broadening for the P(1), Q(1), R(0) and R(1) transitions in the 2ν ₃ band of CH₄ was investigated in the 1660 nm region. The pressure broadening coefficients, γ(gas), were determined for a variety of buffer gases: N₂, O₂, He, Ne, Ar, Kr and Xe. The γ values generally increased with increasing polarizability of the buffer gases. γ(air) are 0.056(2) for P(1), 0.056(1) for R(0), 0.061(1) for R(1) and 0.059(1) for Q(1) in units of cm⁻¹ atm⁻¹ where numbers in parentheses are one standard deviation in units of the last digits quoted. The temperature dependent parameter (broadening exponent) for air is 0.84(7) for P(1) within the temperature range 233–298 K.     

Rovibrational laser jet-cooled spectroscopy of the NH3–Ar complex in the ν2 umbrella region of NH3: comparison between new infrared data and an ab initio calculated spectrum*

ABSTRACT

Five ortho and para bands of the ν₂ umbrella mode of the NH₃–Ar van der Waals complex have been recorded at high resolution using jet-cooled infrared laser spectroscopy. A rovibrational analysis provides accurate band centres and upper state rotational constants for the Π_s(j?=?1,k?=?0)?←?Σ_a(j,k?=?0) and Σ_s(j?=?1,k?=?0)?←?Σ_a(j,k?=?0) ortho bands. The puzzling para bands observed in the region of the lower and upper components of the inversion splitting doublet have been assigned by comparison with rovibrational and tunnelling levels and transitions calculated ab initio. The latter calculations are based on the four-dimensional potential energy surface reported by Loreau et al. [J. Chem. Phys. 141, 224303 (2014)], which takes explicitly into account the umbrella motion of the ammonia molecule. The very good agreement found between Π_s/a,lower(j?=?1,k?=?1)?←?Σ_a(j?=?1,k?=?1) and Π_s/a,upper(j?=?1,k?=?1)?←?Σ_s(j?=?1,k?=?1) experimental and calculated transitions has been exploited to determine precisely two different inversion splittings in the ν₂ state (32.003(1) and 36.008(1)?cm^?1) from extrapolated Q(0) line frequencies and to obtain a qualitative picture of Coriolis couplings present in both the ν₂?=?0 and ν₂?=?1 states.     

The newly observed open-charm states in quark model

Comparing the measured properties of the newly observed open-charm states D(2550), D(2600), D(2750), D(2760), D _s1(2710), D _sJ (2860), and D _sJ (3040) with our predicted spectroscopy and strong decays in a constituent quark model, we find that (1) the D(2 ¹ S ₀) assignment to D(2550) remains open for its too broad width determined by experiment; (2) the D(2600) and D _s1(2710) can be identified as the 2 ³ S ₁–1 ³ D ₁ mixtures; (3) if the D(2760) and D(2750) are indeed the same resonance, they would be the D(1 ³ D ₃); otherwise, they could be assigned as the D(1 ³ D ₃) and D^￠₂(1D)D^{\prime}_{2}(1D), respectively; (4) the D _sJ (2860) could be either the D _s1(2710)’s partner or the D _s (1 ³ D ₃); and (5) both the D _s1(2P) and D^￠_s1(2P)D^{\prime}_{s1}(2P) interpretations for the D _sJ (3040) seem likely. The E1 and M1 radiative decays of these sates are also studied. Further experimental efforts are needed to test the present quarkonium assignments for these new open-charm states.     

SO q (n+1,n−1) as a real form of SO q (2n,ℂ)

Quantum pseudo-orthogonal groups SO _q (n+1,n–1) are defined as real forms of quantum orthogonal groups SO _q (n+1,n–1) by means of a suitable antilinear involution. In particular, the casen=2 gives a quantized Lorentz group.