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1.
We present a 9×9 S-matrix and E-matrix. A representation of specialized Birman-Wenzl-Murakami algebra is obtained. Starting from the given braid group representation S-matrix, we obtain the trigonometric solution of Yang-Baxter equation. A unitary matrix \breve{R}(x,φ12) is generated via theYang-Baxterization approach. Then we construct a Yang-BaxterHamiltonian through the unitary matrix \breve{R}(x,φ12). Berry phase of this Yang-Baxter system is investigated in detail.  相似文献   

2.
B. Allen 《Nuclear Physics B》1983,226(1):228-252
This paper uses zeta-function regularisation to calculate the one-loop functional determinants for fields of any spin in De Sitter space. As an example, we investigate the Coleman-Weinberg spontaneous symmetry breaking mechanism in massless scalar electrodynamics. The effective potential is calculated in Landau gauge. It depends upon the curvature, and upon the renormalised value of ζ (inζRφ2). The phase transition will be first or second order, and the critical curvature and mass are found. The methods can be applied to any gauge theory.  相似文献   

3.
采用数学模拟方法分析了不同背接触势垒高度(φb) 对于CdS/CdTe薄膜电池的J-V(电流密度-电压)方程的影响, 得出了势垒高度与roll-over的变化对应关系. 采用相应Cu/Mo背电极的CdS/CdTe薄膜电池在220-300 K的变温J-V曲线的数值分析与理论分析相对照, 分析了背势垒对于J-V曲线拟合参数的影响. 修正了φb 与反向饱和电流(Jb0)关系式, 理论与实验符合得非常好. 关键词: CdS/CdTe薄膜 伏安特性 肖特基势垒 roll-over  相似文献   

4.
Taking the cosmological expansion rate directly as a function of field φ, H=H(φ), we present a new exact solution to Einstein's equations that describe the evolution of cosmological chaotic inflation model. The inflation is driven by the evolution of scalar field with inflation potential V(φ)=(λ/8)(φ22)2. The spectral indices of the scalar density ns and gravitational wave fluctuations ng are computed. The value of ns lies well inside the limits set by the cosmic background explorer satellite.  相似文献   

5.
In this paper, a new completely integrable system related to the complex spectral problem -φxx+(i/4)uφx+(i/4)(uφ)x+(1/4)vφ=iλφx and the constrained flows of the Boussinesq equations are generated. According to theviewpoint of Hamiltonian mechanics, the Euler-Lagrange equations andthe Legendre transformations, a reasonable Jacobi-Ostrogradskycoordinate system is obtained. Moreover, by means of the constrainedconditions between the potential u, v and the eigenfunction φ, the involutive representations of the solutions for the Boussinesq equation hierarchy are given.  相似文献   

6.
The color number Nc-dependence of the interplay between quark-antiquark condensates (q^-q) and diquark condensates (qq) in vacuum in two-flavor four-fermion interaction models is researched. The results show that the Gs-Hs (the coupling constant of scalar (q^-q)2-scalar (qq)2 channel) phase diagrams will be qualitatively consistent with the case of Nc = 3 as Nc varies in 4D Nambu-Jona-Lasinio model and 219 Gross Neveu (GN) model, However, in 3D GN model, the behavior of the Gs-Hp (the coupling constant of pseudoscalar (qq)^2 channel) phase diagram will obviously depend on No. The known characteristic that a 3D GN model does not have the coexistence phase of the condensates (q^-q) and (qq) is proven to appear only in the case of Nc ≤ 4. In all the models, the regions occupied by the phases containing the diquark condensates (qq) in corresponding phase diagrams will gradually decrease as Nc grows up and finally go to zero if Nc → ∞, i.e. in this limit only the pure (q^-q) phase could exist.  相似文献   

7.
In this paper, we investigate the new agegraphic dark energy model in the framework of Brans-Dicke theory, which is a natural extension of the Einstein's general relativity. In this framework the form of the new agegraphic dark energy density takes as ρq =3n2 φ(t) η-2, where η is the conformalage of the universe and φ(t) is the Brans-Dicke scalar field representing the inverse of the time-variable Newton's constant. We derive the equation of state of the new agegraphic dark energy and the deceleration parameter of the universe in the Brans-Dicke theory. It is very interesting to find that in the Brans-Dicke theory the agegraphic dark energy realizes quintom-like behavior,i.e., its equation of state crosses the phantom divide w=-1 duringthe evolution. We also compare the situation of the agegraphic darkenergy model in the Brans-Dicke theory with that in the Einstein'stheory. In addition, we discuss the new agegraphic dark energy modelwith interaction in the framework of the Brans-Dicke theory.  相似文献   

8.
借助变量筛选方法可以从复杂的光谱背景下选择部分变量构建定量预测模型,在一定程度上提高建模变量的解释性。然而模型解释性的提高并不意味着建模变量有确切的理化意义。本研究以甘草中红外定量预测模型为载体,解析移动窗口偏最小二乘(mwPLS)、组合间隔偏最小二乘(siPLS)和竞争自适应抽样方法(CARS)三种变量筛选方法所得变量与目标成分化学特征的相关性,比较不同变量筛选方法下所筛变量解释性的差异。结果表明,mwPLS优先筛出黄酮和皂苷两类成分红外光谱上区别明显的苯环骨架振动和皂苷母核上甲基取代基弯曲振动所对应的波段,siPLS筛出了黄酮类成分的(φ)C—O,(φ)CC, (φ)C—H伸缩振动的特征区间组合和皂苷类成分的C—O,C—H,O—H伸缩振动的特征区间组合。相对于以上两种变量筛选方法,CARS筛选得到的变量能够更好地归属于甘草苷和甘草酸在中红外1 000~4 000 cm-1特征区的特征峰,而且基于CARS筛选的变量建模,模型的预测性能得到了提高。因此,CARS筛选的变量能实现目标成分红外特征区大部分化学特征的解析,有利于增强模型的解释性。  相似文献   

9.
为了进一步揭示等离子体强化甲烷点火过程的化学动力学机理,设计和搭建了介质阻挡放电等离子体激励空气的实验系统,实验测量了在空气中介质阻挡放电等离子体激励器产生的发射光谱,利用光谱技术分析了等离子体激励空气产生的若干活性粒子,给出了零维均质点火模型以及敏感性分析和化学路径分析的计算方法,模拟了不同初始温度下NO和O3对甲烷点火延迟时间的影响,并分析了活性粒子NO和O3强化甲烷点火的化学动力学过程。研究表明:介质阻挡放电等离子体激励空气主要产生N2和O2的若干激发态粒子,并最终转化成存活时间较长的活性粒子NOx和O3,等离子体对甲烷点火过程的影响可以简化成活性粒子NOx和O3对甲烷点火过程的影响;CH3的氧化速率决定了甲烷点火过程的快慢,在自点火过程中CH3的氧化路径是反应式R155和R156,初始温度较低时R155和R156的反应速率慢,所以甲烷的点火延迟时间长;NO缩短点火延迟时间是由于CH3的氧化路径由自点火过程中的反应式R155和R156改为反应式R327 CH3O2+NO=CH3O+NO2和R328 CH3+NO2=CH3O+NO;O3强化甲烷点火过程同样是由于O3改变CH3的氧化路径,从化学动力学上缩短点火延迟时间。  相似文献   

10.
In the Coleman-Weinberg model (massless scalar quantum electrodynamics), a gauge invariant approximation scheme is obtained by summing vector tadpole graphs to all loop orders. We investigate the influence of this summation on the masses of the scalar and vector particles in the model.  相似文献   

11.
稀土材料红外多光子量子剪裁现象   总被引:1,自引:0,他引:1  
稀土红外量子剪裁为目前国内外的研究热点,它对于提高太阳能电池的效率从而减低太阳能发电的造价很有意义。论文综述了稀土红外量子剪裁的研究意义,在总结了太阳能电池发电和损耗的原理的基础上,分析了稀土红外量子剪裁提高太阳能电池效率的具体途径。同时综述了单掺Er3+材料的稀土红外量子剪裁发光现象:光激发2H11/2能级有很强的4I13/2→4I15/2红外量子剪裁发光,速率很大的{2H11/2→4I9/2,4I15/2→4I13/2}交叉能量传递为导致光激发2H11/2能级有高量子剪裁效率的主要原因。  相似文献   

12.
3,4-噻吩二羧酸(3,4-H2tdc),1,10-邻菲罗啉(phen)和稀土硝酸盐经水热法合成三种配合物Ln2(Htdc)2(tdc)2(phen)2(H2O)4(Ln=Eu 1, Gd 2, Tb 3),并用X-射线单晶衍射分析方法测定了配合物1-3晶体结构,配合物1-3为双核分子。每个金属离子周围有2个3,4-tdc,1个3,4-Htdc,1个phen和2个配位水分子,配位数为9。配合物1和3在紫外灯下显强红光和绿光,其荧光发射光谱,在619和545 nm出现最大发射峰,分别对应于Eu(Ⅲ)离子的5D0→7F2和Tb(Ⅲ)离子的5D4→7F5跃迁。配合物2在425 nm观察到来自基于配体的π*→π最大发射峰。不同溶剂分子对配合物1荧光有不同程度的影响,基于荧光猝灭机理,配合物1具有选择性检测硝基苯污染物的能力。  相似文献   

13.
The phase structure of the SU(5) Coleman-Weinberg theory in the one-loop approximation is obtained with account of temperature and space-time curvature. We show that the most essential contribution is that from the interaction between 5 and 24 scalar fields which reflects the existence of two strongly different mass scales in the model. A stability boundary of the SU(3) × SU(2) × U(1) phase is found. It is shown that the SU(4) × U(1) phase in the Coleman-Weinberg theory is unstable.  相似文献   

14.
土壤含盐量与电导率的高光谱反演精度对比研究   总被引:15,自引:0,他引:15  
探明土壤盐渍化的高光谱遥感监测机理,对改善高光谱遥感监测精度具有重要意义。以南疆地区温宿县、和田县、拜城县的水稻土为研究对象,通过分析土样的高光谱数据和室内测定的盐分与电导率数据,研究了耕作土壤含盐量与电导率的关系,并比较了含盐量和电导率与不同光谱指标的相关性以及二者高光谱反演的精度。结果表明,南疆水稻土的含盐量与电导率的相关性较低,二者之间的关系因地区差异而有较大的变化;含盐量与反射率、一阶微分、连续统去除之间的相关性要优于电导率,特别在一些土壤盐渍化的敏感波段尤为突出;以含盐量建立的多元线性回归、主成分回归、偏最小二乘回归模型的决定系数和相对分析误差均高于电导率。研究表明高光谱信息对土壤含盐量的响应比电导率更敏感,以含盐量为监测指标的高光谱反演精度明显要优于电导率。该结果可为提高土壤盐渍化高光谱遥感监测精度提供理论依据。  相似文献   

15.
采用密度泛函理论对以偶氮二异丁腈为引发剂形成的丙烯腈单体自由基(CH3)2(CN)C—CH2—(CN)CH的终止方式反应机理进行研究。先用B3LYP/6-31G(d)基组对反应物、偶合中间体、过渡态、歧化产物的几何构型进行优化,并计算了各物种经过零点能校正后的总能量,红外频率和电子结构,同时对过渡态结构进行了验证。研究结果表明,反应物先通过自由基的偶合终止方式形成偶合中间体a,再由此经过氢迁移、裂解等机理得到歧化终止产物P[p1(CH3)2(CN)CCHCHCN+p2(CH3)2(CN)C—CH2—CH2CN]。双自由基发生偶合和歧化终止反应分别形成偶合中间体a和歧化终止产物P均为放热反应,且偶合产物有着更低的能量。反应过程的速控步骤a→TS→P在常温下的速率常数表示为k(298.15 K)=2.71×10-59。歧化终止反应随着反应温度的升高易于进行,歧化产物所占的比例也增加。通过对反应过程各物种红外谱图的分析,说明自由基在整个终止反应的化学变化,同时分析了HOMO-LUMO电子密度分布的信息,验证丙烯腈双自由基偶合终止方式和各物种结构的准确性。  相似文献   

16.
The constraint on the total energy in a given spatial region is given from holography by the mass of a black hole that just fits in that region, which leads to an UV/IR relation: the maximal energy density in that region is proportional to Mp^2/L^2, where Mp is the Planck mass and L is the spatial scale of that region under consideration. Assuming the maximal black hole in the universe is formed through gravitational collapse of perturbations in the universe, then the "Jeans" scale of the perturbations gives a causal connection scale RCC. For gravitational perturbations, RCC^-2= Max (H+ 2H^2, -H) for a fiat universe. We study the cosmological dynamics of the corresponding vacuum energy density by choosing the causal connection scale as the IR cutoff in the UV/IR relation, in the cases of the vacuum energy density as an independently conserved energy component and an effective dynamical cosmological constant, respectively. It turns out that only the case with the choice RCC^-2 = H+ 2H^2, could be consistent with the current cosmological observations when the vacuum density appears as an independently conserved energy component. In this case, the model is called holographic Ricci scalar dark energy model in the literature.  相似文献   

17.
Using the extended Blonder-Tinkham-Klapwijk formalism, we investigate the conductance spectra of normal metal/dx2-y2+idxy mixed wave superconductor graphene junctions. It is found that the conductance spectra vary strongly with the orientation of the gap and the amplitude ratio (Δ10) of two components for dx2-y2+idxy mixed wave. The zero bias conductance isnearly 2 and the conductance peak vanishes in doped graphene forα=0 and Δ10=1. The conductance increases with increasing the amplitude ratio of two components for α=π/4 and Δ10=1. The ZBCP becomesobservable wide with 1F/Δ0<100 for α=π/4 and Δ10=1. This property is different from that in normal metal/dx2-y2 wave superconductor graphenejunctions.  相似文献   

18.
云开地块西南缘的庞西垌复式岩体由外而内、由上而下依次为花岗片麻岩、片麻状花岗岩和花岗岩,即由高级变质岩渐变过渡至岩浆岩。X射线荧光光谱、等离子体质谱对三类岩石的分析结果表明,三类岩石皆属于过铝质岩石系列,造岩组分和微量元素具有渐变过渡的特征。在花岗片麻岩演化为花岗岩的熔融、分异过程中,Al2O3,CaO,MgO与TiO2等造岩组分含量逐渐增高,SiO2含量逐渐降低;稀土元素总量整体升高,稀土元素中轻稀土含量逐渐增高,而重稀土含量逐渐降低,显示出轻重稀土分异增强的特征,在多期演化过程中,形成了具有亲缘演化基因的庞西垌花岗质岩石系列。这表明云开地块表变质壳岩石的重熔可能是花岗质岩石的重要成因。其演化机制可能是,表壳岩石在发生熔融之后SiO2最先脱离母岩不断熔出,重稀土可能随着SiO2熔体逐渐向上富集;而Al2O3,CaO,MgO,TiO2以及轻稀土相对SiO2则向下富集。  相似文献   

19.
磷石膏中微量含氟物相的光谱分析   总被引:1,自引:0,他引:1  
磷石膏中二水硫酸钙(CaSO4·2H2O)的含量高达90%以上,是一种重要的再生石膏资源。然而与天然石膏不同,磷石膏中磷、氟、有机物等有害杂质限制了它的实际利用。探明微量杂质氟物相的存在形态、含量及分布规律,对高效脱除磷石膏中杂质氟具有重要的理论价值。采用X射线光电子能谱(X-ray photoelectron spectroscopy, XPS)与电子显微探针(electron microprobe analysis, EMPA)相结合的分析方法,研究了磷石膏中微量含氟物相的主要存在形式和分布规律。结果表明,磷石膏中微量含氟物相主要包括NaF,KF,CaF2,K2SiF6,Na2SiF6,Na3AlF6,K3AlF6,AlF3·3H2O,AlF2.3(OH)0.7·H2O,Ca5(PO4)3F,Ca10(PO4)6F2。其中,4.83%的氟以NaF,KF,CaF2等氟化物形式存在,8.42%的氟以氟磷酸盐Ca5(PO4)3F和Ca10(PO4)6F2形式存在,12.21%的氟以氟铝酸盐Na3AlF6和K3AlF6形式存在,41.52%的氟以氟硅酸盐K2SiF6和Na2SiF6形式存在,33.02%的氟以带结晶水的氟化铝AlF3·3H2O和AlF2.3(OH)0.7·H2O形式存在。研究表明分析固体样品中微量元素物相时,采用XPS与EMPA相结合的分析方法更具有优势。本研究为磷石膏中微量杂质氟的脱除以及有效回收氟资源提供理论依据。  相似文献   

20.
Quintessence field is a widely-studied candidate of dark energy. There is ``tracker solution' in quintessence models, in which evolution of the field ø at present times is not sensitive to its initial conditions. When the energy density of dark energy is neglectable (Ωø<< 1), evolution of the tracker solutioncan be well analysed from ``tracker equation'. In this paper, we try tostudy evolution of the quintessence field from ``full tracker equation',which is valid for all spans of Ωø. We get stable fixed points of wø and Ωø (noted as \hat{w}ø and \hat{Ω}ø) from the ``full tracker equation', i.e., wø and Ωø will always approach \hat{w}ø and \hat{Ω}ø respectively. Since \hat{w}ø and \hat{Ω}ø are analytic functions of ø, analytic relation of \hat{w}ø ~ \hat{Ω}ø can be obtained, which is a good approximation for the wø ~ Ωø relation and can be obtained for the most type of quintessence potentials. By using this approximation, we find that inequalities \hat{w}ø < wø and \hat{Ω}ø < Ωø are statisfied if the wø (or \hat{w}ø) decreases with time. In this way, the potential U(ø) can be constrained directly from observations, by no need of solving the equations of motion numerically.  相似文献   

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