菲佐测风激光雷达及风速反演算法

 研制了基于菲佐干涉仪的测风激光雷达系统,并使用高斯拟合法和最大似然法反演风速,对两种风速反演方法进行了分析,结果表明：风速较小时,两种方法具有相似的风速反演精度,但高斯拟合法收敛快、受条纹信噪比影响较小;风速较大时,高斯拟合法会由于条纹移出而产生较大误差,而最大似然法在处理风速较大情况时具有优势。实际风速测量时,应根据风速估计值的大小,采用两种方法分别处理大风速和小风速时的情况。最后,使用研制的测风激光雷达系统和风速反演算法,得到了1.5 km以内的大气风速廓线。     

不确定非线性光电伺服系统滑模自适应控制

针对同时存在参数不确定性和结构不确定性的非线性光电伺服系统,运用自适应原理对系统的参数进行在线估计,同时提出一种改进的指数趋近律,并结合滑模控制（变结构控制）策略设计系统的滑模自适应位置控制器（APR）。以等效正弦1.2sin(0.93t)作为仿真输入,在0.45s后跟踪误差小于60μrad,表明该控制方法对此类不确定非线性系统的控制效果良好。     

光散射法测量颗粒尺寸、浓度的实验研究

为了能够准确快速地求解出微米量级颗粒系的尺寸和浓度,设计了一套基于Fraunhofer衍射,以线阵CCD为接收器件的实验颗粒测量装置.采用Shifrin积分变换方法,分析了给定样品颗粒的粒径分布、峰值、平均值和体积浓度.实验结果表明,与传统的Swithenbank方法采用环形光电管阵列为探测器接收衍射光强来反演颗粒分布方法相比,该方法不需要知道颗粒粒径上下限,各粒径区间间隔等预知信息,而且对粒径、浓度的实验测量值与理论值相差较小,样品峰值粒径为9.849 8 μm,与给定峰值的相对误差为3.432%,具有较高的测试准确度和较好的测试效果.     

双通道数字红外辐射计的研究

 针对目前所使用的红外辐射强度测试系统的不足,提出双通道数字红外辐射计的方案,即在同一红外辐射计中设计两套相互独立的红外辐射强度测试通道,在红外辐射产品点火试验测试中,双通道测试同时工作,同时进行数据采集。用研制的双通道数字红外辐射计分别在室温（25℃）和低温（-15℃）条件下进行6次对比试验,结果表明：两系统测试的误差小于5%,双通道数字红外线辐射计两通道之间误差小于5％,原1905A测试系统出现2次漏测,双通道数字红外辐射计无漏测。     

脉冲激光偏振特性用于目标的探测识别

针对光电探测时仅用强度来处理信息的局限性,通过理论分析,提出一种利用脉冲激光反射、散射偏振态时间、空间相关检测的方法,可以克服由于强度差过小带来的目标检测上的困难.利用分析结论,通过计算偏振分布密度函数(Stokes矢量的概率密度函数),进一步讨论了偏振传递函数的特性,用于识别目标,并给出了计算实例.     

Impact parameter and beam energy dependence for azimuthal asymmetry of direct photons and free protons in intermediate energy heavy-ion collisions

Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter phase. In this work, we have calculated the impact parameter and beam energy dependence for azimuthal asymmetry, characterized by directed transverse flow parameter F and elliptic asymmetry coefficient v₂, of direct photons and the corresponding free protons in intermediate energy heavy-ion collisions. It is further shown the anti-correlated azimuthal asymmetry between direct photons and free protons.     

Measuring physical parameters with surface plasmon resonance heterodyne interferometry

If the incident angle of a light beam on the boundary surface between the thin metal film of a surface plasmon resonance (SPR) apparatus and a test medium is equal to or very near the resonant angle, then the phase difference between the p- and s-polarizations of the reflected light is related to the associated physical parameter. The phase difference can be measured accurately with heterodyne interferometry. If the relationship between the phase difference and the associated physical parameter is specified, then the associated physical parameter can be estimated from the phase difference data. This method has the benefits of both common-path interferometry and heterodyne interferometry, such as simple structure, high stability, high resolution, easy operation, and rapid real-time measurement.     

Bianchi Type V Cosmological Models with Constant Deceleration Parameter in General Relativity

We investigate Bianchi type V cosmological models with bulk viscous fluid source. Exact solutions of the Einstein field equations are presented via a suitable power law assumption for the Hubble parameter. We show that the corresponding solutions retain the well established features of the standard cosmology and in addition, are in accordance with recent type Ia supernovae observations. Some observational parameters for the models have also been discussed.     

Analysis and algorithms for a regularized cauchy problem arising from a non-linear elliptic PDE for seismic velocity estimation

In the present work we derive and study a non-linear elliptic PDE coming from the problem of estimation of sound speed inside the Earth. The physical setting of the PDE allows us to pose only a Cauchy problem, and hence is ill-posed. However, we are still able to solve it numerically on a long enough time interval to be of practical use. We used two approaches. The first approach is a finite difference time-marching numerical scheme inspired by the Lax–Friedrichs method. The key features of this scheme is the Lax–Friedrichs averaging and the wide stencil in space. The second approach is a spectral Chebyshev method with truncated series. We show that our schemes work because of (i) the special input corresponding to a positive finite seismic velocity, (ii) special initial conditions corresponding to the image rays, (iii) the fact that our finite-difference scheme contains small error terms which damp the high harmonics; truncation of the Chebyshev series, and (iv) the need to compute the solution only for a short interval of time. We test our numerical schemes on a collection of analytic examples and demonstrate a dramatic improvement in accuracy in the estimation of the sound speed inside the Earth in comparison with the conventional Dix inversion. Our test on the Marmousi example confirms the effectiveness of the proposed approach.     

Quantum-chemical calculations of the structure,vibrational spectra,and torsional and inversion potentials of methylcarbamate

We present results of ab initio and DFT calculations of the structure, potential functions of the methyl group internal rotation and the amino group inversion, and vibrational frequencies and intensities in IR and Raman spectra of methylcarbamate. The calculations were carried out using different basis sets in the HF, MP2, and DFT/B3LYP approximations. The influence of both the basis set size and the allowance for electronic correlation on peculiarities of the structure of the amino group in methylcarbamate has been analyzed. It is shown that the B3LYP/6-311++G(2d, p) and B3LYP/cc-pVDZ calculations reproduce highly accurately experimental geometric parameters of methylcarbamate. Parameters of torsional and inversion potentials and characteristics of vibrational spectra calculated in different approximations show satisfactory agreement with experimental values. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 349–357, May–June, 2009.