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1.
(2s+1)维希尔伯特空间q—畸变谐振子奇相干态的光学性质 总被引:1,自引:0,他引:1
构造了(2s 1)维希尔伯特(Hilbert)q-畸变谐振子奇相干态,讨论了其量子统计特性。发现(2s 1)维希尔伯特空间q-畸变谐振子相干态与通常无限维空间的奇q-相干态和奇相干态有明显不同的压缩及反聚束效应。 相似文献
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Double Electron Processes in Collisions of Partially Stripped Ions C^q+ (q = 1-4) with Helium 下载免费PDF全文
The multi-electron processes are investigated for 17.9-120 keV/u C^1+, 30-323 keV/u C^2+, 120-438 keV/u ^C3+, 287-480 keV/u C^4+ incident on a helium target. The cross-section ratios of double electron (DE) process to the total of the single electron (SE) and the double electron process (i.e. SE+DE), the direct double electron (DDI) to the direct single ionization (DSI) as well as the contributions of DDI to DE and of TI to DE are measured using coincidence techniques. The energy and charge state dependences of the measured cross-section ratios are studied and discussed. 相似文献
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《中国物理快报》2003,20(5):622-625
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Peakon and Foldon Excitations in a (2+1)—Dimensional Breaking Soliton System 总被引:7,自引:0,他引:7 下载免费PDF全文
《中国物理快报》2003,20(6):783-786
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Cross-section ratios σTI/σSC of transfer ionization (TI) to single capture (SC) of C^q+- and O^q+-He (q = 1 - 3) collisions in the energy range of 15-440 keV/u (0.8-4.2 vBohr) are experimentally determined. It is shown that σTI/σSC strongly depends on the projectile velocity, and there is a maximum for E(keV/u)/q1/2 ≈, 150. Combining the Bohr-Lindhard model and the statistical model, a theoretical estimate is presented, in reasonable agreement with the experimental data when E(keV//u)/q^1/2 〉 35. 相似文献
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Dromion and Multi—soliton Structures of the (2+1)—Dimensional Higher—Order Broer—Kaup System 总被引:1,自引:0,他引:1 下载免费PDF全文
Using the standard truncated Painleve analysis and the Backlund transformation,we can obtain many significant exact soliton solutions of the (2 1)-dimensional higher-order Broer-Kaup(HBK) system.A special type of soliton solution is described by the variable coefficient heat-conduction-liker equation.The inclusion of three arbitrary functions in the general expressions of the solitons makes the solitons of the (2 1)-dimensional HBK system possess abundant structures such as solitoff solutions,multi-dromion solutions,ring solitons and so on. 相似文献
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In this paper,the variable separation approach is used to obtain localized coherent structures of the (2 1)-dimensional generalized Davey-Stewarson equations:iqt 1/2(qxx=qyy) (R S)q=0,Rx=-σ/2|q|y^2,Sy=-σ/2|q|2/x.Applying a special Baecklund transformation and introducing arbitrary functions of the seed solutions.and abundance of the localized structures of this model is derived,By selceting the arbitrary functions appropriately,some special types of localized excitations such as dromions,dromion lattice,breathers,and instantons are constructed. 相似文献
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Moessbauer Studies on Spin Transition in Zinc Dilution Complexes [Fe1—xZnx(dpp)2(NCS)2]py(x=0.05—0.40) 下载免费PDF全文
A series of spin transition complexes [Fe1-xZnx(dpp)2(NCS)2]ph(x=0.05,0.10,0.15,0.20,0.25,and 0.40;py=pyridine) has been synthesized and studied by Moessbauer spectroscopy.The high-spin structure is frozen at room temperature,and the induced meta-stable high-spin phase by the so-called rapid cooling method is monitored by temperature and time-dependent Moessbauer spectra.The investigation on dynamic relaxation of the high-spin state to the low-spin state at 80-K reveals sigmoid behaviour and existence of cooperative effect for low diluted complexes.This cooperative effect is wrecked by the dilution of Zn(Ⅱ)ions in Fe(Ⅱ)ion sites,and relaxation curves gradually become to obey the first-order kinetics as the ratio of the dilution increases. 相似文献
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Explicit and exact travelling plane wave solutions of the (2+1)—dimensional Boussinesq equation 总被引:1,自引:0,他引:1 下载免费PDF全文
The deformation mapping method is applied to solve a system of (2+1)-dimensional Boussinesq equations. Many types of explicit and exact travelling plane wave solutions, which contain solitary wave solutions,periodic wave solutions,Jacobian elliptic function solutions and others exact solutions, are obtained by a simple algebraic transformation relation between the (2+1)-dimensional Boussinesq equation and the cubic nonlinear Klein-Gordon equation. 相似文献
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Structures and luminescence properties of Yb3+ in the double perovskites Ba2YB'O6 (B'=Ta5+, Nb5+) phosphors 下载免费PDF全文
The Yb3+ doped Ba2YB'O6 (B'=Ta5+, Nb5+) were prepared by high temperature solid-state reaction method, their structures were determined by x-ray diffraction and refined by Rietveld method. The diffuse reflection absorption, excitation and emission spectra of Yb3+:Ba2YB'O6 (B'=,Ta5+, Nb5+) were measured at room temperature. Under the excitation of ultraviolet light, these phosphors exhibit broad charge transfer band emissions of TaO6 or NbO6 centre with large Stokes shift. The Yb3+ doped into these hosts are situated at Y3+ sites of cubic symmetry (Oh). The experimental energy levels of Yb3+ in Ba2YTaO6 and Ba2YNbO6 were determined by photoluminescence and diffuse reflection absorption spectra. Their wavefunctions and theoretical energy levels were obtained by diagonalising the Hamiltonian matrix. The experimental energy levels were fitted by Levenberg--Marquardt iteration algorithm to determine crystal field parameters. Then, the magnetic-pole transition line strengths of Yb3+:Ba2YB'O6(B'=Ta5+, Nb5+) from (2F5/2)Γ8- to the low-energy states were calculated. 相似文献
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本文利用最近研制的低温离子阱-离子速度成像谱仪在冷离子束中研究了同位素质量分辨的79Br2+分子离子的[1+1]双光子激光解离动力学. 借助其14Σ-u,3/2态为中间态使79Br2+共振吸收两个光子至4∽5 eV区域的高激发态并发生解离. 利用离子速度成像技术获得了光解产物79Br+的二维速度分布和平动能释放谱. 通过平动能释放谱确定了不同解离能量处量子态分辨的解离产物通道分支比. 光碎片产物的角分布表明79Br2+分子离子的双光子解离是14Σ-u,3/2态的ΔΩ=0平行跃迁至一个Ω=3/2高解离态发生的. 由于分子激发态中的强自旋-轨道耦合作用,高激发的四重态很可能参与到实验观测的光解过程. 相似文献
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Nanocrystalline Y3Al5O12: Ce3+/Tb3+ (average crystalline size 30 nm) phosphor layers were coated on non-aggregated, monodisperse and spherical SiO2 particles by the sol-gel method, resulting in the formation of core-shell structured SiO2@Y3Al5O12:Ce3+/Tb3+ particles. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, photoluminescence,
cathodoluminescence spectra, as well as lifetimes were utilized to characterize the core-shell structured SiO2@Y3Al5O12:Ce3+/Tb3+ phosphor particles. The obtained core-shell structured phosphors consist of well-dispersed submicron spherical particles
with a narrow size distribution. The thickness of the Y3Al5O12:Ce3+/Tb3+ shells on the SiO2 cores (average size about 500 nm, crystalline size about 30 nm) could be easily tailored by varying the number of deposition
cycles (100 nm for four deposition cycles). Under the excitation of ultraviolet and low-voltage electron beams (1–3 kV), the
core-shell SiO2@Y3Al5O12:Ce3+/Tb3+ particles show strong yellow-green and green emission corresponding to the 5d–4f emission of Ce3+ and 5D4–7F
J
(J = 6, 5, 4, 3) emission of Tb3+, respectively. These phosphors may have potential application in field emission displays. 相似文献
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三基色荧光粉中, 红色荧光粉性能较差, 为获得性能优良的红色荧光粉, 本文采用高温固相法合成了Eu2+, Cr3+单掺杂及共掺杂的碱土金属多铝酸盐MAl12O19 (M =Ca, Sr, Ba) 发光体. 实验表明, 在以上三种基质中均存在Eu2+→Cr3+的能量传递, 利用能量传递可以有效将Eu2+的蓝光或绿光转换为红光. 三种碱土金属多铝酸盐基质的晶体结构相似,但Eu2+, Cr3+发光受晶体场影响,导致在不同的基质中Eu2+, Cr3+间能量传递效率不同.通过光谱分析及能量传递效率计算发现, 相同掺杂浓度下,CaAl12O19中Eu2+→Cr3+的能量传递效率最高,SrAl12O19次之, BaAl12O19最低.红光转换率在CaAl12O19中最高. 相似文献
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本文使用交叉分子束方法研究了氟原子和振动激发态氘分子D2(v=1, j=0)的反应. 使用受激拉曼抽运的方法制备了振动激发的D2分子. 实验中未观测到来自于旋轨耦合激发态氟原子F*(2P1/2)与振动激发态D2分子的贡献. 观测到来自于旋轨耦合基态氟原子F(2P3/2)和振动激发态D2的反应信号,相应的产物DF分子布居于v''=2,3,4,5振动态上. 与振动基态反应F+D2(v=1,j=0)相比,振动激发态反应F+D2(v=1,j=0)生成的DF产物转动分布更“热”. 获得了振动激发反应的四个碰撞能在0.32至2.62 kcal/mol范围内的微分反应截面. 在最低的碰撞能0.32 kcal/mol下,所有振动态的DF产物都以后向散射为主. 随着碰撞能的增加,DF产物的角分布逐渐从后向转移到侧向. 测量了DF(v''=5)产物的前向微分散射截面随碰撞能变化的曲线. 前向散射的DF(v''=5)信号出现于1.0 kcal/mol. 在2.62 kcal/mol碰撞能下DF(v''=5)主要为前向散射. 相似文献
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Synthesis and characterization of Sr3Al2O6:Eu2+, Dy3+ phosphors prepared by sol-gel-combustion processing 下载免费PDF全文
A type of red luminescent Sr3Al2O6:Eu2+, Dy3+ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol-gel, it is found that it is necessary to reduce the amount of NO3- by dropping ethanol into the solution for forming a stable and homogeneous sol-gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3Al2O6:Eu2+, Dy3+. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250 C. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of (Sr0.94Eu0.03Dy0.03)3Al2O6 phosphors sintered at 1250 ℃ lasts for over 1000 s when the excited source is cut off. 相似文献
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利用单模连续的钛宝石激光器, 构建了一台光腔衰荡光谱仪, 其可探测的最小吸收可达1.8×10-10/cm. 该光谱仪被用来记录C2H2分子在12240~12350 cm-1的泛频光谱. 与在同一波段测量的已报到的CRDS和激光腔内吸收光谱仪结果比较,本测量同时具有更好的灵敏度和精度. 由此,获得了乙炔分子在12290.12、12311.82和12350.61 cm-1附近高泛频谱带更准确的振转参数 相似文献