激光离子源双脉冲打靶方案的实现（英文）

设计并实现了近代物理研究所激光离子源双脉冲打靶方案以产生高电荷态离子束。从Nd:YAG激光器输出的激光束经过一对分光棱镜的分束-合束,通过改变两束光的光程差,得到有一定时间延迟的双激光脉冲。利用四分之一玻片,双脉冲的能量比值可以在3:8～8:3之间连续调节。为了验证该方案的可行性,对C靶进行了初步实验。实验结果发现,与以往单脉冲打靶方案对比,双脉冲方案在离子束的脉冲时间结构和电荷态分布有所不同。但是,导致这些差异的机理和实验的优化还尚需要进一步研究。     

Jaffe与Wilczek双夸克模型中的负宇称五夸克态

如果Jaffe与Wilczek关于Q5+五夸克态的双夸克图像是正确的话,那就应该存在负宇称的五夸克SU(3)八重态与单态,其中两个双夸克间没有轨道激发.这些态比Q5+质量低,与传统夸克模型中的由三夸克构成的重子的轨道激发质量接近.我们计算了这些负宇称态的质量与磁矩,用手征有效拉氏量讨论了他们可能的强衰变模式和选择定择，发现有两个态可能比较窄.我们建议实验上寻找这九个额外的负宇称态.如果将来的实验确实发现了这些态,那是对Jaffe与Wilczek双夸克模型的直接验证.否则,应该重新评估Jaffe与Wilczek的双夸克图像甚至抛弃这个模型.     

远程制备双原子纠缠态

提出一种远程制备双原子纠缠态的方案,该方案基于两个原子与单模腔场的同时非共振相互作用.由于双粒子纠缠态比三粒子纠缠态容易制备,方案用两对双原子纠缠态作为量子通道.Alice 拥有的两个相同原子同时与一单模腔场非共振相互作用.Alice已知她要制备的纠缠态,她选择适当的相互作用时间、测量她所拥有的两个原子并通过经典通道通知Bob.Bob引入一个相同的辅助原子和一个单模腔场来实现方案.方案对腔场状态和腔损耗不敏感,基于当前的腔QED 技术,方案能在实验上实现.该方案有望在量子信息过程中有重要的应用价值.     

导出双粒子纠缠态表象的新途径

对于量子光学的双粒子纠缠态表象,我们给出一个新途径以分析其在福克空间中的表达式.此分析自然导致双变数厄密多项式的引入,它截然不同于单变数厄密多项式.     

杨氏双缝干涉实验中双缝缝宽的讨论

首先基于惠更斯菲涅尔原理,推导了双缝具有一定宽度时的双缝干涉光强表达式。根据该解析表达式,利用数学软件进行数值模拟,结果发现:当双缝具有一定宽度时,双缝干涉条纹不再是理想的等亮度等间距的干涉条纹,而是从中间往外光强将逐渐衰减,并且在一定的双缝间距和缝宽比值时,还会出现条纹消失的现象。对于这些理论模拟结果,给予了相应的解释。此外,还进行了相应的实验观测,实验结果和理论结果基本一致。本论文所讨论的内容,对于进一步完善和深入讨论杨氏双缝干涉实验的教学和实验内容具有一定的指导意义。     

双电桥灵敏度的探讨

一般的大学物理实验教科书中,都安排了“用双电桥测低电阻”这个实验。但对双电桥灵敏度未作进一步的讨论,本文试图对此作些探讨。一、双电桥电路图1给出了它的原理性电路。其中R_x是被测电阻,     

半导体中的双激子压缩态及其复合辐射

本文引进双激子压缩态,在单激子“非玻色近似”和玻色近似两种情形下,讨论了量子关联和空间关联的双激子的压缩特性、二阶相关特性及其复合辐射光的压缩特性,说明两种情形下双激子玻色近似分别相当于SU(2)群和SU(1,1)群到谐振子群的收缩,并给出这种收缩所带来的结果。 关键词：     

双光束干涉法测量双棱镜的楔角

在双光束干涉实验中测量出干涉条纹间距,在波长已知的条件下计算出虚光源的间距。利用光的折射定律可推导出虚光源间距和双棱镜的楔角的关系,从而计算出双棱镜的楔角。     

高离化金离子态-态双电子复合速率系数

研究了类铍Au⁷⁵⁺离子三类态-态双电子复合过程，基于多组态准相对论自洽场 方法和 扭曲波方法，计算了该离子在电子温度0.6—10.0keV范围内的态-态双电子复合速率系数， 并讨论了它们随电子温度、复合类型和上下能态的变化. 关键词： 75+离子')" href="#">Au⁷⁵⁺离子 态-态双电子复合     

同核双原子分子的热力学性质

本文对热运动能量ｋＴ远小于分子离解能εｄ时的同核双原子分子的热力学性质作了一般性讨论．     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer

With a novel light-weight and absolutely calibrated ultraviolet （UV） spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands （320 - 335 nm） using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model （Tracy）. The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.     

Design optimization of highly sensitive LSPR enhanced surface plasmon resonance biosensors with nanoholes

For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently.But in practice, these structures have obvious disadvantages.In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA).Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters.The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes.Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves' width are obtained simultaneously under optimized structural parameters.     

Polymer gratings based on photopolymerization for low-order distributed feedback polymer lasers

Novel polymer distributed feedback(DFB)gratings are fabricated based on photopolymerization to reduce lasing threshold of polymer lasers.A photopolymer formulation sensitive to 355-nm ultraviolet(UV)light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process.A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012.The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.