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1.
尹铭  林振权  柯见洪 《中国物理 B》2011,20(8):88201-088201
This paper proposes a pest propagation model to investigate the evolution behaviours of pest aggregates. A pest aggregate grows by self-monomer birth, and it may fragment into two smaller ones. The kinetic evolution behaviours of pest aggregates are investigated by the rate equation approach based on the mean-field theory. For a system with a self-birth rate kernel I(k)=Ik and a fragmentation rate kernel L(i,j)=L, we find that the total number M0A(t) and the total mass of the pest aggregates M1A(t) both increase exponentially with time if L ≠ 0. Furthermore, we introduce two catalysis-driven monomer death mechanisms for the former pest propagation model to study the evolution behaviours of pest aggregates under pesticide and natural enemy controlled pest propagation. In the pesticide controlled model with a catalyzed monomer death rate kernel J1(k)=J1k, it is found that only when I<J1B0 (B0 is the concentration of catalyst aggregates) can the pests be killed off. Otherwise, the pest aggregates can survive. In the model of pest control with a natural enemy, a pest aggregate loses one of its individuals and the number of natural enemies increases by one. For this system, we find that no matter how many natural enemies there are at the beginning, pests will be eliminated by them eventually.  相似文献   

2.
The mixed spin 3–spin 3/2 ferrimagnetic Ising model was simulated using cooling algorithm on cellular automaton (CA). The simulations were carried out in the intervals ?4 ≤ DA/J ≤ 8 and ?4 ≤ DB/J ≤ 8 for the square lattices with periodic boundary conditions. The ground-state phase diagram of the model has different types of ferrimagnetic phases. Although only the antiferromagnetic nearest-neighbor interaction was contained in the Hamiltonian, the compensation points emerged through DA/J = 2 at kT/J = 0. The values of the critical exponents (ν, α , β and γ) were estimated within the framework of the finite-size scaling theory and power-law relations for the selected DA/J values (?2, 0, 1, 2, and 4). The estimated critical exponent values were in good agreement with the universal values of the two-dimensional Ising model (ν = 1, α = α′ = 0, β = 0.125, β′ = 0.875 and γ = γ′ = 1.75).  相似文献   

3.
We examine the long-time behavior of A+B0 reaction-diffusion systems with initially segregated species A and B. All of our analysis is carried out for arbitrary (positive) values of the diffusion constantsD A andD B and initial concentrationsa 0 andb 0 of A's and B's. We divide the domain of the partial differential equations describing the problem into several regions in which they can be reduced to simpler, solvable equations, and we merge the solutions. Thus we derive general formulas for the concentration profiles outside the reaction zone, the location of the reaction zone center, and the total reaction rate. An asymptotic condition for the reaction front to be stationary is also derived. The properties of the reaction layer are studied in the mean-field approximation, and we show that not only the scaling exponents, but also the scaling functions are independent ofD A,D B,a 0 andb 0.  相似文献   

4.
5.
The parallel band ν6(A2) of C3D6 near 2336 cm?1 has been studied with high resolution (Δν = 0.020 – 0.024 cm?1) in the infrared. The band has been analyzed using standard techniques and the following parameters have been determined: B″ = 0.461388(20) cm?1, DJ = 3.83(17) × 10?7 cm?1, ν0 = 2336.764(2) cm?1, αB = (B″ ? B′) = 8.823(12) × 10?4 cm?1, βJ = (DJ ? DJ) = 0, and αC = (C″ ? C′) = 4.5(5) × 10?4 cm?1.  相似文献   

6.
We analyze B 0(+)JD 0(+) decays by considering the contributions of annihilation diagrams. For each diagram, we calculate the branching ratios for various parameters X A , which have played a significant role in our results. These parameters have been concluded from the divergence integrals in hard-scattering kernels. Here, we have considered three effective variables, including: Λ(225, 500 MeV), ρ A (0, 1, 1/2), and φ A . It is found that the most of the obtained data are placed in the experimental range at Λ = 225 MeV and Λ = 500 MeV for B +JD + and B 0JD 0, respectively.  相似文献   

7.
A variational procedure for rovibrational energy levels and wavefunctions of centrally connected tetra-atomic molecules is extended to include high rotational states, and in particular, J ? 10 levels for the vibrational ground state of formaldehyde. It is very important to do this because it has made possible the calculation of the usual rotational spectroscopic constants which correspond to the forcefield and geometry. A direct comparison with the ‘observed’ spectroscopic constants is therefore possible. The geometry and forcefield are refined against 65 J = 0 levels of H2CO, 6 J = 0 levels of D2CO, 42 J = 1, 70 J = 2 and 98 J = 3 levels of the ground and fundamentals of H2CO and D2CO, using an iterative scheme. The mean absolute error of the J = 0 levels is 1·10 cm?1 and that for J ≠ 0 is 0·005 cm?1, and the predicted geometry is CH = 1·10064 Å, CO = 1·20296 Å and HCO = 121·648°. Finally, the rotational constants A, B, and C for the ground state are 281956, 38846 and 34003 MHz, compared with the observed values 281971, 38836, and 34002 MHz. The centrifugal distortion constants ΔJ , ΔJK , ΔK and δJ , are 77, 1275, 18113 and 11 kHz compared with 75, 1291, 19422 and 10 kHz. These results underline the accuracy of the new quartic forcefield.  相似文献   

8.
The 2ν3(A1) band of 12CD3F near 5.06 μm has been recorded with a resolution of 20–24 × 10−3 cm−1. The value of the parameter (αB − αA) for this band was found to be very small and, therefore, the K structure of the R(J) and P(J) manifolds was unresolved for J < 15 and only partially resolved for larger J values. The band was analyzed using standard techniques and values for the following constants determined: ν0 = 1977.178(3) cm−1, B″ = 0.68216(9) cm−1, DJ = 1.10(30) × 10−6 cm−1, αB = (B″ − B′) = 3.086(7) × 10−3 cm−1, and βJ = (DJDJ) = −3.24(11) × 10−7 cm−1. A value of αA = (A″ − A′) = 2.90(5) × 10−3 cm−1 has been obtained through band contour simulations of the R(J) and P(J) multiplets.  相似文献   

9.
A pair (A, B) of events in a classical probability measure space (Ω, p) is called exchangeable iff p(A ) = p( B). Conditionally identical common cause system of size n for the correlation is an n-partition of Ω such that (i) any member of the partition screens the correlation off and (ii) for any member {C i } iI of the partition p(A|C i ) = p(B|C i ). The common cause system is called proper if p(A|C i )≠(A|C j ) for some ij. In the paper it is shown that exchangeable correlations be explained by proper conditionally identical common cause systems in the following sense. (i) Given a proper conditionally identical common cause system of size n for the two events A and B in Ω, then the pair (A, B) will be an exchangeable (positively) correlating pair. (ii) Given any exchangeable (positively) correlating pair of events in Ω and given any finite number n > 2, then the probability space can be embedded into a larger probability space in such a way that the larger space contains a proper conditionally identical common cause system of size n for the correlation.  相似文献   

10.
The formation and optical properties of J aggregates of pseudoisocyanine iodide in solid films in the presence of cluster anionic derivatives of boron hydrides and carboranes (B10H 10 2- , B12H 12 2- , B20H 18 2- , [NiIV(1,2-B9C2H11)2]0, 1,2-B9C2H 12 - , [Co(1,2-B9C2H11)2]-, [Ni(1,2-B9C2H11)2]-, B10H8I 2 2- , [Sn(1,2-B9C2H11)]0) are studied. It is shown that the addition of anions B10H 10 2- or B10H8I 2 2- leads to an efficient formation of stable J aggregates. The addition of carborane complex of nickel [NiIV (1,2-B9C2H11)2]0 also leads to the formation of J aggregates, although less stable ones. Carborane complex of tin [SnII(1,2-B9C2H11)]0 facilitates the formation of a monomeric form of the dye. The remaining compounds yield no distinct pattern of formation of a certain monomeric or J-aggregated film structure. With the aid of the semiempirical AM1 method, the charge distributions in the cation of the dye and anionic derivatives of the boron hydrides are calculated. It is supposed that the bipolar distribution of a negative charge in the B10H 10 2- anion facilitates the formation of a J aggregate. By addition of salts of organic cations to a film of pseudoisocyanine-closo-hydrodecaborate (PCG), J aggregates with a narrow width of the J peak are obtained. The thermal decay of J aggregates in these films is studied. On the basis of the data obtained (the presence of an isosbestic point upon thermal decomposition of J aggregates and their reaggregation; the narrowing and increasing of the J absorption peak, as well as increasing of luminescence, upon dilution of a J-aggregated PCG film with organic cations; and the bipolar character of the electrostatic interaction of the B10H 10 2- anion with the dye), it is assumed that the J peak of pseudoisocyanine in the films studied corresponds to the absorption of a dimeric form of the dye.  相似文献   

11.
Under the assumptions thatq is not a root of unity and that the differentialsdu j i of the matrix entries span the left module of first order forms, we classify bicovariant differential calculi on quantum groupsA n–1 ,B n ,C n andD n . We prove that apart one dimensional differential calculi and from finitely many values ofq, there are precisely2n such calculi on the quantum groupA n–1 =SL q (n) forn3. All these calculi have the dimensionn 2. For the quantum groupsB n ,C n andD n we show that except for finitely manyq there exist precisely twoN 2-dimensional bicovariant calculi forN3, whereN=2n+1 forB n andN=2n forC n ,D n . The structure of these calculi is explicitly described and the corresponding ad-invariant right ideals of ker are determined. In the limitq1 two of the 2n calculi forA n–1 and one of the two calculi forB n ,C n andD n contain the ordinary classical differential calculus on the corresponding Lie group as a quotient.  相似文献   

12.
刘慧  邢伟  施德恒  朱遵略  孙金锋 《物理学报》2011,60(4):43102-043102
利用内收缩多参考组态相互作用方法和价态范围内的最大相关一致基aug-cc-pV6Z, 在0.05—0.60 nm的核间距范围内计算了CS+离子X2Σ+和A2Π态的势能曲线. 利用CS+离子的势能曲线并在同位素质量修正的基础上, 拟合出了X2Σ+和A2Π态的同位素离子1 关键词: 同位素识别 势能曲线 光谱常数 分子常数  相似文献   

13.
Bound states and critical behavior of the Yukawa potential   总被引:1,自引:0,他引:1  
We investigate the bound states of the Yukawa potential V (r)=−λexp(−αr)/r, using different algorithms: solving the Schr?dinger equation numerically and our Monte Carlo Hamiltonian approach. There is a critical α = αC, above which no bound state exists. We study the relation between αC and λ for various angular momentum quantum number l, and find in atomic units, αC(l) = λ[A 1 exp(−l/B 1) + A 2 exp(−l/B 2)], with A 1 = 1.020(18), B 1 = 0.443(14), A 2 = 0.170(17), and B 2 = 2.490(180).  相似文献   

14.
Umegaki's relative entropyS(,)=TrD (logD –logD ) (of states and with density operatorsD andD , respectively) is shown to be an asymptotic exponent considered from the quantum hypothesis testing viewpoint. It is also proved that some other versions of the relative entropy give rise to the same asymptotics as Umegaki's one. As a byproduct, the inequality TrA logAB TrA(logA+logB) is obtained for positive definite matricesA andB.  相似文献   

15.
H. Vogler 《Molecular physics》2013,111(5):1179-1193
The lower excited singlet and triplet states and the zero-field splitting parameters D of [2.2]paracyclophane are studied within a semiempirical π theory which takes into account overlap effects between the two benzene rings, transanular and through-bond interaction via the methylene bridges. Whereas the singlet energies depend strongly on the through-bond interaction and the mutual polarization of σ core and π system this is not the case for the energies and zero-field splitting parameters D of the two lowest triplet states. The deformations of the benzene rings in [2.2]paracyclophane lead only to a small decrease of the excitation energies of about 0·2 eV. The D parameter can be written as a sum D = DA + DB + DAB with the intrasubunit contributions DA and DB of the conjugated subunits A and B of the phane and an intersubunit term DAB . We demonstrate that the deformations reduce the intrasubunit terms DA and DB and that they are crucial for the decrease of the D values of [2.2]paracyclophane with respect to p-xylene. The difference between the D values of the first and second triplet states is governed by the intersubunit term DAB which has a different sign in the two states. However, this difference does not depend markedly on the transanular interaction. A further reduction of DA and DB in the first triplet state only is caused by transanular interaction by means of symmetrical charge-transfer terms in the wavefunction.  相似文献   

16.
Rotational analysis of bands arising from A (v = 0 through 9) and B (v = 0 through 7) states in and systems of As2 molecule has been carried out. Important perturbations are observed, and the Bv-values are not constant with J, except for the three levels A (v = 0), A (v = 1) and B (v = 1), for which they are, respectively, 0.07202 ± 0.00001, 0.073199 ± 0.000007, and 0.077770 ± 0.000003 cm−1. Bv-curves of the other levels are plotted against J.  相似文献   

17.
The oscillator representation is applied to calculate the energy spectrum of three-body Coulomb systems with total angular momentum J. For three-body Coulomb systems with J = 1 and arbitrary masses the region of stability is determined. For the systems (A + A e ), (pe C +), (pB e ), and (D + e e +), the values of the critical masses of the particles A, B, C, and D are obtained as m A = 2.22m e , m B = 1.49m e , m C = 2.11m e and m D = 4.15m e . Received November 6, 1995; received December 4, 1995; accepted for publication January 22, 1996  相似文献   

18.
The two conceptual systems of organic homologous compounds and homo‐rank compounds give insight into the influence of structures on the properties of mono‐substituted alkanes Xi–(CH2)j–H from the transverse (change of repeating unit number j of CH2) and longitudinal (change of functional group Xi) perspectives, respectively. This paper aims to combine the organic homo‐rank compounds approach together with the homologous compounds approach to explore the property change rules of mono‐substituted alkanes involving various substituents. Firstly, based on the concept of organic homologous compounds, the properties of mono‐substituted straight‐chain alkane homologues were linearly correlated to the two‐thirds power of the number of carbon atoms (N2/3) in alkyl, and regression equations such as Q = A + BN2/3 were obtained. The regression coefficients A and B vary with different substituents Xi, so coefficients A and B were employed to characterize the structural information of substituent Xi. The structural features of alkyls (–(CH2)j–H, that is, –CjH2j+1) were described by the polarizability effect index (PEI(R)) and vertex degree–distance index (VDI). Then based on four parameters A, B, PEI(R), and VDI, quantitative structure–property relationship models were built for the boiling points (Bp) and refractive indexes (nD) of each mono‐substituted alkane homo‐rank series, where j = 3–10 and the substituents Xi involve F, Cl, Br, I, NO2, CN, NH2, COOH, CHO, OH, SH, and NC. Good results indicate that the combination of an organic homo‐rank compounds method and a homologous compounds method has exhibited obvious advantages over traditional methods in the quantitative structure–property relationship study of mono‐substituted alkanes concerning various substituents. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

19.
The effect of the Dzyaloshinskii-Moriya (DM) interaction on the heat conduction in the quantum Ising chain has been studied by solving the Lindblad master equation. The chain is subject to a uniform transverse field h, while the exchange couplings {J m } between the nearest-neighbor spins are either uniform, random or quasi-periodic. The average energy-density profile and the average energy current in the non-equilibrium steady state have been numerically calculated. The ballistic transport is observed in the uniform Ising chain with DM interaction. For the random Ising chain with DM interaction, the energy gradient is observed in the bulk of the spin chain whose energy current appears to scale as the system size ⟨Q⟩ ∼ exp(βN) with β < 0. For the quasi-periodic Ising chain with DM interaction, the J m takes the two values J A and J B arranged in the Fibonacci sequence. The energy gradient also exists in the spin chain and the energy current behaves as ⟨Q⟩ ∼ N α with α < 0. By increasing the strength of the DM interaction D, a non-trivial transition from the thermal insulator heat transport to anomalous heat conduction is found in the Fibonacci Ising chain with large ratio of couplings λ = J A /J B . A rough phase diagram of λ vs. D is given in this paper as well.  相似文献   

20.
The 2ν3(A1) band of 12CD3F near 5.06 μm has been recorded with a resolution of 20–24 × 10?3 cm?1. The value of the parameter (αB ? αA) for this band was found to be very small and, therefore, the K structure of the R(J) and P(J) manifolds was unresolved for J < 15 and only partially resolved for larger J values. The band was analyzed using standard techniques and values for the following constants determined: ν0 = 1977.178(3) cm?1, B″ = 0.68216(9) cm?1, DJ = 1.10(30) × 10?6 cm?1, αB = (B″ ? B′) = 3.086(7) × 10?3 cm?1, and βJ = (DJ ? DJ) = ?3.24(11) × 10?7 cm?1. A value of αA = (A″ ? A′) = 2.90(5) × 10?3 cm?1 has been obtained through band contour simulations of the R(J) and P(J) multiplets.  相似文献   

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