相位不连续点对自适应光学的影响

 分析了激光在湍流大气中传输时，若光束波前中出现相位不连续点，自适应光学校正能力降低的原因，通过数值模拟计算了当光束波前中出现相位不连续点时对自适应光学校正的影响，表明在传输过程中出现不连续点的情况下，为了提高自适应光学的校正能力，必须要考虑不连续相位的影响。     

LD端面抽运Nd:YAG 1319nm/1338nm双波长激光器研究

从LD端面抽运固体激光器的激光阈值公式出发，建立了双波长激光同时振荡的阈值条件，理论计算了腔镜对于两个波长的透过率关系，实现了LD端面抽运Nd:YAG 1319nm/1338nm双波长激光连续和准连续输出.双波长激光连续输出功率可达6W，斜效率为30%；准连续输出功率在重复频率50kHz时可达4.75W，斜效率为24.73%，脉冲宽度为55.05ns；腔内插入布儒斯特片，在重复频率为50kHz时，双波长激光准连续线偏振输出功率可达2.22W，不稳定性小于0.52%，M²     

连续扫描全画素CCD摄像系统

本文阐述了连续扫描和隔行扫描ＣＣＤ（ｃｈａｒｇｅ－ｃｏｕｐｌｅｄｄｅｖｉｃｅ）摄像机的工作方式和特征，较详细地介绍了连续扫描ＣＣＤ的工作原理，用图示给出了两种扫描方式的比较。连续扫描方式可从每一个独立像素中获得在一个信号曝光周期之间产生的信号。对于在高分辨率成像情况下，在必需捕捉迅速运动目标的应用领域中，连续扫描ＣＣＤ是最佳的选择。     

激光二极管泵浦单频连续工作的Nd：YAG激光器

在国内首次报道了激光二极管泵浦单频连续工作的Ｎｄ：ＹＡＧ激光器，采用扭摆模腔技术方法，在８０８ｎｍ激光二极管连续泵浦下，取得１０６４ｎｍ连续单频工作，输出功率５５ｍＷ的结果，泵浦阈值２７６ｍＷ，斜率效率２３％，线宽小于２５ＭＨｚ（受仪器测量精度限制）。     

强湍流效应下不同信标波长的自适应光学校正

激光在大气中长距离传输时所产生的相位不连续点的数目与位置不仅与大气湍流和传输距离有关，而且与传输的激光波长有关。由于对主激光进行补偿的相位是从畸变的信标光场中获得的，当畸变光场中出现相位不连续点后，畸变光场的相位由连续相位部分和不连续相位部分组成，不连续相位部分直接与畸变光场中出现的相位不连续点的数密度和其所在的位置有关，一般情况下，主激光的波长与信标光的波长是不同的，因此当主激光的波长一定后，为了对不连续相位进行补偿，以便提高强湍流效应条件下的自适应光学校正能力，必须要考虑合作信标的波长。计算结果表明，考虑了不连续相位的影响后，虽然对主激光的校正效果有所改善，但对不同波长的信标改善的效果并不相同，只有信标光波长稍长于主激光的波长时，校正效果才有明显的改善。     

连续频率散斑光栅膜测量技术的研究

提出了一种新的连续频率散斑光栅膜测量技术，给出了该技术的理论和方法，它可用于研究很大范围内的变形，其灵敏度可从０￣６００１／ｍｍ范围内连续选取，或更高。     

制作连续沟形微光学元件的新方法

提出一种制作连续沟形微光学元件的新方法，用移动物面上二元图案的方法来获得连续灰度的记录，再用卤化银明胶处理技术，把灰度银像转化成明胶硬度潜像，最后采用酶蚀显影工艺把潜像显现为连续沟形的浮雕结构，文中给出了原理分析和实验验证，初步结果令人满意。     

LD列阵泵浦Nd:YAG连续激光器

介绍了一种二极管侧面泵浦的Nd:YAG连续激光器，采用了简单，实用的侧面泵浦结构，获得了37．9W的连续1064nm的激光多模输出，斜效率为31．5％，光准效率为23．7％，文中还对该泵浦头的热透镜效应作了测试。     

细菌视紫红质膜快速光开关的实验研究

建立了“脉冲激光－连续探测光－连续擦除光”的实验系统。在532nm的调Q脉冲激发光和不同波长的连续探测光作用下，研究了细菌视紫红质（BR）膜的光循环过程中的快速响应特性及各中间态的快速光吸收特性。观察到了微秒量级的快速光开关现象，并分析了激发光脉冲作用结束时，各中间态上细菌视紫红质分子的分布。     

半导体激光器的线宽压窄及频率连续调谐

我们利用共焦F—P腔光学弱反馈技术，实现了单模GaAlAs半导体激光器线宽压窄、频率锁定及连续调谐。其线宽从自由运转时的10MHz被压窄到45kHz，并可将频率锁定于共焦F—P腔。实验证明，在弱反馈情况下，激光器的频率连续调谐范围与共焦FP腔的光强反馈量近似成正比，实现了在铷原子D2线附近1．2GHz的频率连续调谐，     

On the most accurate measurements of the wavelengths of X-ray spectral lines

The paper discusses the influence of statistical errors in measuring the intensity of a spectral line on the exact determination of its wavelength. Using simplifying assumptions, it is shown that the relative error in measuring the wavelengths of spectral lines of the same type, caused by the statistical character of X-ray intensity measurements and by the influence of the true width of the spectral line, is practically constant under the same conditions, i.e. it is independent of the lattice parameters of the crystals used and of the wavelength of the spectral line. It seems that the latest exact measurements of Bearden confirm this result.The greatest care should therefore be devoted to the neighbourhood of inflection points of the curve representing the spectral line profile when making exact measurements of the spectral position of the lines.The author heartily thanks Professor M. A. Blochin for valuable remarks on this work.     

耳蜗中tip-link张力与静纤毛运动动力学研究

诠释耳蜗的主动感音放大机制一直是未解的医学难题.这种机制与耳蜗中外毛细胞顶端的静纤毛运动密切相关,静纤毛运动又受到tip-link张力与淋巴液流体力的调节.因此,研究静纤毛运动过程中tip-link张力是诠释耳蜗的主动感音放大机制的重要环节.本文把静纤毛视为变形体,基于泊肃叶流动理论并结合分布参数模型,推导了静纤毛运动的解析解.研究了盖膜剪切荷载作用下静纤毛和淋巴液相互作用的动力响应以及tip-link张力的变化规律.研究发现:当静纤毛的杨氏模量减小时,在小于峰值频率的区域,tip-link张力显著增大,f₂的峰值频率减小.以往的研究将静纤毛作为刚体,势必导致低频声音信号作用减弱.当系数c=0 (无黏性阻力)时,f₂频率选择特性存在;当μ=0(无压力)时,f₂频率选择特性消失,因此淋巴液可能是通过在静纤毛间产生压强的方式来调节毛束的频率特性的.另外,盖膜剪切荷载频率越高,静纤毛轴弯曲越明显,发束内外域的压强差也越大.     

线型分子的电子能级之Λ分裂的新解释

认为电子态能级发生Λ分裂虽然是角动量引起的,但不是耦合而是运动牵连作用的结果.从这一认识出发,利用欧拉方程和拉格朗日方程分别得到了包含Λ分裂的分子转动哈密顿函数和哈密顿算符,所得结果与Van.Vleck的著名结论完全一致 关键词： Λ分裂 线型分子 欧拉方程 哈密顿算符     

Nonlinear optical response of an atom in the field of femtosecond laser pulses with near-atomic intensity

A theory of the nonresonant response of a single atom in a state with arbitrary magnitude and direction of the angular momentum of an atomic electron with respect to the polarization vector of the acting electromagnetic field has been developed. It has been shown that the atomic response current has a tensor structure and depends both on the direction of the angular momentum of the atom and on the polarization vector of the external field. The tensor character of the response is due to the effects of the anisotropy of probability density distribution of the atomic electron as compared to the case of the free atom. The selection rules for the axisymmetric problem of the atom in the field have been analyzed. The manifestation of the selection rules in the angular spectra of photoelectrons has been demonstrated. The probability of the ionization of the atom has been analyzed as a function of the amplitude and duration of the pulse. It has been shown that the width of the generation spectrum is a nonlinear function of the field strength and is saturated in the region of nearly atomic fields. Methods for controlling the parameters of the atomic response spectrum have been proposed on the basis of the use of a sequence of laser pulses with various time profiles, carrier frequencies, and polarization states. It has been shown that the generation of terahertz radiation is possible in the preionization regime, where the generation mechanism is attributed to atomic nonlinearity.     

Statistical theory of a solvated electron in an electrolyte

The behavior of a solvated electron in an electrolyte is investigated. The formalism of the theory is based on variational estimation of path integrals. It reduces the problem to the investigation of the self-consistent mean field produced by the ions and the electron. Mayer cluster expansions make it possible to take account of the short-range interactions and to find expressions for the effective potential of the electron and the electron-ion and electron-neutral atom correlation functions as a function of the macro-and microscopic parameters of electrolytes. In the limit of high ion densities the behavior of the electron is determined solely by the Coulomb interaction, which results in the formation of a polaron state. This state of the electron is virtually independent of the thermodynamic parameters of the electrolyte. In the opposite limit of low ion densities the electron forms a cavity state. The presence of ions results in additional localization of the electron and is manifested experimentally as a shift of the absorption band in the direction of high energies. The estimated shift for a hydrated electron agrees with the experimental data. Zh. éksp. Teor. Fiz. 115, 1463–1477 (April 1999)     

固体火箭发动机羽流辐射光谱测温方法研究

固体火箭发动机羽流具有高温、高速与强辐射特征,羽流温度是发动机工作状态与性能的重要表征参数。准确测量固体火箭发动机羽流温度对了解发动机内部燃烧情况以及发动机综合性能具有重要的参考价值。随着激光与光谱学的发展,激光光谱技术逐步应用于固体推进剂燃烧及发动机羽流温度测量。辐射光谱测温法通过测量火焰辐射光谱来实现温度的非接触在线测量,具有测温范围宽、响应快及可靠性高等优点,可应用于固体火箭发动机羽流温度测量。在此提出了基于火焰辐射光谱的固体火箭发动机羽流温度测量方法,采用350～1 000 nm波段光纤光谱仪搭建了发动机羽流火焰辐射光谱测量系统,利用标准辐射黑体炉开展光谱仪响应系数标定,获得响应系数随波长的变化曲线,并以此用作羽流辐射光谱数据修正。之后将该测量系统应用于标准Φ118固体火箭发动机地面试验,开展典型12%铝质量含量推进剂发动机羽流辐射光谱实验测量,选取不同时刻羽流辐射光谱分析了发动机羽流辐射光谱特征,并利用双色法灰性判断原理对羽流火焰灰体特性进行讨论,验证在675～745 nm波段发动机羽流火焰辐射可近似认为灰体,该波段辐射率随波长变化最大相对偏差为4.01%,相对均方差为1.53%。因此,基于普朗克辐射定律开展辐射光谱拟合参数获得不同时刻羽流温度与辐射率参数,并讨论测量结果与发动机工作状态的关系。最后,开展12%,15%与19%铝质量含量的不同推进剂配方固体火箭发动机羽流辐射光谱测量,将辐射光谱法温度测量值与理论热力计算值进行比较,两者最大偏差值为5.40%,讨论了不同铝含量推进剂发动机羽流辐射光谱特征,并结合温度与辐射率测量结果,分析了固体推进剂铝含量对辐射光谱、羽流温度及辐射率的影响。通过固体火箭发动机羽流辐射光谱测温方法研究,为固体火箭发动机性能评估及推进剂配方优化等研究提供了有效的羽流参数测量手段。分析获得的推进剂铝含量对发动机羽流辐射光谱、温度及辐射率参数的影响,为降低固体发动机羽流特征信号提供了重要的实验数据支撑。     

强耦合表面激子内部激发态的性质

采用线性组合算符和幺正变换方法,研究极性晶体中强耦合表面激子内部激发态的性质.计算了表面激子的激发态能量、激发能量和平均声子数.     

高速模型尾迹流场及其电磁散射特性相似性实验研究

高速目标再入大气层或在临近空间飞行时,空气电离形成的等离子体鞘套和尾迹对目标的雷达散射特性会产生影响.为了研究不同模型尾迹流场及其电磁散射特性规律和相似性,以氧化铝球模型为研究对象,在弹道靶设备上开展了双尺度参数相同的条件下高速球模型尾迹流场及其电磁散射相似性实验研究.由二级轻气炮发射模型,模型直径分别为8.0、10.0、12.0、15.0 mm,速度约6 km/s,靶室压力分别为6.3,5.0,4.2,3.3 k Pa,采用阴影照相系统测量模型激波脱体距离、电子密度测量系统测量模型尾迹的电子密度分布、X波段单站雷达系统测量在视角为40?的模型及流场的雷达散射截面(RCS)分布.实验结果表明:在速度不变、双尺度参数相同的条件下,随着模型尺寸的增加,激波脱体距离逐渐增加,激波脱体距离与模型直径之比近似相同;不同模型尾迹电子密度测量曲线的趋势和数量级一致,表明不同模型的尾迹流场适用于双缩尺律;不同尺寸模型尾迹的总体RCS与分布RCS均不相同,表明不同模型尾迹的电磁散射不适用于二元缩尺律;高速球模型全目标电磁散射能量分布在模型及其绕流区域、等离子体尾迹区域;高速球模型全目标电磁散射能量在模型及绕流场区域出现1个强散射中心,在模型湍流尾迹区域出现多个散射中心;高速球模型尾迹的RCS测量信号呈现随机性分布特性,幅度脉动和频率脉动均没有周期性;随着模型尺寸的增加,模型尾迹的总体RCS增加,尾迹脉动频率的变化范围减小.     

Photomagnetism of metals. first observation of dependence on polarization of light

We report the first observation of the polarization dependence of the d.c. photocurrent induced by illumination in Cu. The dependence of a d.c. photocurrent on the direction of the plane of light polarization is measured. In agreement with the theoretical considerations, the current parallel to the plane of light incidence is a symmetric function of the angle between this plane and the plane of light polarization. The angular-dependent part of the current perpendicular to the plane of light incidence is an antisymmetric function of the angle.     

Dynamics of Spin Temperatures in EPR on Rapid Switching of the Frequency Detuning of a Saturating Field

In the framework of the spin temperature in EPR in the absence of interaction with the lattice, the time-dependent change in the spin temperatures of the Zeeman subsystem and dipole-dipole reservoir has been investigated theoretically in the high-temperature approximation. It is shown that amplification in the system can be obtained by switching the detuning of the saturating field frequency. The approach to the solution of the problem is based on the fact that during the process of switching and establishment of both temperatures the total energy of the Zeeman subsystem and of the dipole-dipole reservoir is preserved. It has been established that the values of absorption or amplification in the system depend on the frequency detunings of the saturating field. In the presence of a probe field, the possibility of determining the value of the local magnetic field related to the time of transverse relaxation of the system is demonstrated.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 171–175, March–April, 2005.