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1.
陈志坚  姚德成 《光学学报》1995,15(4):32-436
报道在镁金属蒸气中利用两束激光三光子共振激发原子3snp1P中高里德堡态时,观察到随泵浦激光功率的增强,出现3s4s1S0-3sns1S0、3snd1D2(n≈18~32)偶宇称态偶极禁戒跃迁增强,以及3sns1S0能级移动现象,并解释为光泵过程引起的原子激发态碰撞效应。利用禁戒跃迁首次测定了Mg3sns1S0(n=22~30)能级。  相似文献   

2.
饱和克尔介质中双光子J—C模型的原子动力行为   总被引:1,自引:0,他引:1  
唐慧琴  朱开成 《光学学报》1996,16(11):549-1553
讨论了高Q饱和克尔介质腔中单个两能级原子与单模光场发双光子相互作用时原子动力学行为的演化。  相似文献   

3.
单个囚禁离子的Jaynes—Cummings模型   总被引:6,自引:0,他引:6  
杨晓雪  吴颖 《光学学报》1998,18(8):050-1055
Cirac等人证明处于驻波光场波节处的单个囚禁两能级离子的动力学由Jaynes-Cum-mings(J-C)模型描述。本文旨在推广这一结论。通过引入穿衣态描述,证明处于驻波光场中任意位置时,单个囚禁的两能级离子的动力学仍由相同模型描述。  相似文献   

4.
本文给出用R-N技术求解非线性方程的算法描述,讨论用缟级语言实现该算法的一些问题,最后给出一具体运算实例。  相似文献   

5.
研究电源的输出功率和负载的关系是一个重要的电学实验,也是对学生进行图象教学的典型实验.我校学生用的实验器材为WYJ-20/2A高精度直流稳压电源、C31-A型电流表(0.5级)、J236-1型电阻箱(0.5级)、开关、导线等.实验电路图如图1所示,R为负载,R0为定值电阻,充当电源的假内阻,当E、R0调到一定值(如E=6.0 V,R0=10.0Ω)后,调节R的阻值,测量电路中的电流I,计算输出功率P=I2R,在坐标纸上作出P-R图象,可直观地反映输出功率与负载电阻的关系,其图象如图2所示.  相似文献   

6.
报道了一种新型有机材料znTBP—CA—PhR的光学非线性吸收特性,此材料在激光作用下,在可见光区域具有反饱和吸收,再反饱和吸收和饱和吸收效应.同时发现该材料优良的光学限幅性能,不仅光限幅的阈值低,而且限幅前光透射呈线性状态没有光学非线性效应.用5能级结构模型及速率方程模拟了饱和及反饱和的实验曲线,分析了非线性吸收等的物理机理.  相似文献   

7.
在对圆极化光调谐及一些近似处理的基础上,圆极化光场中阻尼V-型三能级原子分为6个能级,并针对强场的弱场两种情形,导出了原子能级与能级衰减系数的具体表达式。  相似文献   

8.
本文采用Hypersil-ODS2(4.6mm×250mm,5μm)色谱柱,乙腈-水(70∶30)流动相,242nm测定波长,建立了测定2-苯基4-对甲苯基-1,5-苯并硫氮杂(艹)/(卓)-α-(丁二酰亚胺基)-β-内酰胺高效液相色谱法.该法线性范围为0-0.1mg/mL,回归方程A=2.11×108C-3.10×105,相关系数r=0.9995,相对标准偏差为0.24%(C=0.06mg/mL,n=5),检出限为0.05μg/mL.平均回收率在97.1%-102.4%之间.该法重现性好、灵敏度高、简单、快速、准确.  相似文献   

9.
10.
郝振芳 《光谱实验室》2003,20(2):260-262
应用高效液相色谱外标定量法对2-对甲氧基苯基-4-苯基-1,5-苯并硫氮杂(艹卓)-α-(丁二酰亚胺基)-β-内酰胺进行了测定.采用Hypersil-ODS2(4.6mm×250mm,5μm)柱,乙腈与水按70∶30(V/V)组成流动相,测定波长为242nm,该方法线性范围为0-0.1mg/mL,回归方程A=1.91×108C-3.82×105,相关系数r=0.9994,相对标准偏差为0.72%,检出限为0.05μg/mL,平均回收率在98.4%-101.8%之间.该法重现性好、灵敏度高、简单、快速.  相似文献   

11.
论证了在赝带隙光子晶体中存在一个全频率域态总数守恒规则,在完全带隙光子晶体中还存在一个局域态总数守恒规则.态总数守恒规则指出,如果一个光子晶体的态密度在某些频率范围存在相对于等效介质态密度的谷,则一定由其他频率范围内相对于等效介质态密度的峰来补偿.使用符合态总数守恒规则的态密度模型,解释了态密度调制导致的自发辐射谱增强、抑制、变窄、红移、蓝移以及谱分裂等光子晶体中的量子光学现象.该理论比较适合研究在具有赝带隙的光子晶体中大量随机分布的发光原子或分子的自发辐射行为. 关键词: 光子晶体 自发辐射 态密度 光子赝带隙  相似文献   

12.
In attempt to clarify the significance of interspecific interactions in evolutionary ecology, the growth characteristics of bacterial populations sampled from ecological microcosms which act as fairly realistic models of natural ecosystems were investigated, with a particular emphasis on the ability of a system to remain reasonably stable in the genetic composition in spite of the occurrences of various mutants from native strains. Newly-emerged mutants in a community are inhibited in their multiplication, or excluded by a network of many elementary interactions between the different species of the populations, thus preserving the traits of the parental strains in a community. The interactions in the form of a network may be viewed as evidence for a maintenance of stability in a community.  相似文献   

13.
We study the Dirac and the Klein-Gordon oscillators in a noncommutative space. It is shown that the Klein-Gordon oscillator in a noncommutative space has a similar behaviour to the dynamics ofa particle in a commutative space and in a constant magnetic field. The Dirac oscillator in a noncommutative space has a similar equation to the equation of motion for a relativistic fermion in a commutative space and in a magnetic field, however a new exotic term appears, which implies that a charged fermion in a noncommutative space has an electric dipole moment.  相似文献   

14.
A theory of an electron affinity for an ionic cluster is proposed both in a quasiclassical approach and with quantization of a polarization electric field in a nanopartiele. A critical size of the cluster regarding in formation of an electron's autolocalized state, dependencies of energy and radius of a polaron on a cluster's size are obtained by a variational method. It has been found that binding energy of the electron in the cluster depends on a eluster's radius but a radius of electron's auto-localization does not depend on the cluster's radius and it equals to the polaron radius in a corresponding infinity crystal. A bound state of the electron in a cluster is possible only if the duster's radius is more than the polaron radius.  相似文献   

15.
Analytical formulas for the average intensity and decentered parameter of a decentered elliptical Gaussian beam (DEGB) propagating in a turbulent atmosphere are derived in a tensor form. The propagation properties of a DEGB in a turbulent atmosphere are investigated in detail, and found to be different from that in free space. Furthermore, as an application example, we investigate the propagation of a decentered elliptical flat-topped beam (DEFB) by expressing its electric field as a finite sum of DEGBs in a turbulent atmosphere. The properties of a DEGB or a DEFB in a turbulent atmosphere are closely related with the beam’s parameters and the structure constant of the turbulent atmosphere.  相似文献   

16.
Collective motion is abundant in nature, producing a vast amount of phenomena which have been studied in recent years, including the landing of flocks of birds. We investigate the collective decision making scenario where a flock of birds decides the optimal time of landing in the absence of a global leader. We introduce a simple phenomenological model in the spirit of the statistical mechanics-based self-propelled particles (SPPs) approach to interpret this process. We expect that our model is applicable to a larger class of spatiotemporal decision making situations than just the landing of flocks (which process is used as a paradigmatic case). In the model birds are only influenced by observable variables, like position and velocity. Heterogeneity is introduced in the flock in terms of a depletion time after which a bird feels increasing bias to move towards the ground. Our model demonstrates a possible mechanism by which animals in a large group can arrive at an egalitarian decision about the time of switching from one activity to another in the absence of a leader. In particular, we show the existence of a paradoxical effect where noise enhances the coherence of the landing process.  相似文献   

17.
Jie-Hui Huang 《中国物理 B》2022,31(11):110307-110307
Since the evolution of a mixed state in a unitary system is equivalent to the joint evolution of the eigenvectors contained in it, we could use the tool of instantaneous angular velocity for pure states to study the quantum speed limit (QSL) of a mixed state. We derive a lower bound for the evolution time of a mixed state to a target state in a unitary system, which automatically reduces to the quantum speed limit induced by the Fubini-Study metric for pure states. The computation of the QSL of a degenerate mixed state is more complicated than that of a non-degenerate mixed state, where we have to make a singular value decomposition (SVD) on the inner product between the two eigenvector matrices of the initial and target states. By combing these results, a lower bound for the evolution time of a general mixed state is presented. In order to compare the tightness among the lower bound proposed here and lower bounds reported in the references, two examples in a single-qubit system and in a single-qutrit system are studied analytically and numerically, respectively. All conclusions derived in this work are independent of the eigenvalues of the mixed state, which is in accord with the evolution properties of a quantum unitary system.  相似文献   

18.
19.
We describe dynamical processes in continuous media with a long-term memory. Our consideration is based on a stochastic subordination idea and concerns two physical examples in detail. First we study a temporal evolution of the species concentration in a trapping reaction in which a diffusing reactant is surrounded by a sea of randomly moving traps. The analysis uses the random-variable formalism of anomalous diffusive processes. We find that the empirical trapping-reaction law, according to which the reactant concentration decreases in time as a product of an exponential and a stretched exponential function, can be explained by a two-time scale subordination of random processes. Another example is connected with a state equation for continuous media with memory. If the pressure and the density of a medium are subordinated in two different random processes, then the ordinary state equation becomes fractional with two-time scales. This allows one to arrive at the Bagley-Torvik type of state equation.  相似文献   

20.
非完整映射理论与刚体定点转动的几何描述   总被引:3,自引:0,他引:3       下载免费PDF全文
王勇  郭永新  吕群松  刘畅 《物理学报》2009,58(8):5142-5149
利用非完整映射方法,从一个已知Riemann空间构造一个嵌入其中的Riemann-Cartan空间.作为特例,研究从Euclidean空间构造Weitzenbock空间的方法.基于dAlembert-Lagrange原理和非完整映射,将一个Riemann空间的测地线对应于另一个Riemann-Cartan空间的自平行线.把这种非完整映射理论应用到刚体定点转动问题上,得到了刚体运动的欧拉方程是欧拉角描述的Riemann位形空间的测地线方程,而在刚体角速度对应的准坐标空间上是常挠率Riemann-Cartan空间的自平行线方程的结论. 关键词: 欧拉角 非完整映射 Riemann-Cartan空间 自平行线  相似文献   

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