An analysis of error propagation in Abel inversions of spectral emission-absorption data

This paper investigates the effects of several influences upon the accuracy of Abel inversions which are performed upon spectral emission-absorption data that are obtained from axisymmetric sources of radiation.The influences that are investigated are the numerical step size that is used in the inversion, uncertainty in source diameter, and Gaussian noise superimposed upon the data. The effects of graphical and numerical data smoothing upon inversion results that are obtained with noisy data are also investigated. Graphical smoothing is found to be superior to quadratic curve fitting.     

非理想背光照相对靶壳阿贝尔密度反演的影响

建立了背光照相的模拟手段,研究了记录屏像素尺寸、背光强度分布、背光光谱非单色、针孔弥散及针孔形状对惯性约束聚变中常用塑料球壳的阿贝尔密度反演的影响。结果表明：较大的记录屏像素尺寸会掩盖密度分布的细节;高斯型的背光空间分布会使密度分布低于真实值,可能导致非物理的负密度分布;采用Mo的L带谱线作为背光源也会导致反演密度偏离真实值;当壳层厚度小于针孔尺寸时,针孔弥散效应会显著降低峰值密度,利用维纳滤波法处理背光图像后密度反演的结果得到明显改善;相同针孔面积条件下,椭圆形针孔给出的峰值密度要低于圆形针孔的结果。     

非理想背光照相对靶壳阿贝尔密度反演的影响

建立了背光照相的模拟手段,研究了记录屏像素尺寸、背光强度分布、背光光谱非单色、针孔弥散及针孔形状对惯性约束聚变中常用塑料球壳的阿贝尔密度反演的影响。结果表明:较大的记录屏像素尺寸会掩盖密度分布的细节;高斯型的背光空间分布会使密度分布低于真实值,可能导致非物理的负密度分布;采用Mo的L带谱线作为背光源也会导致反演密度偏离真实值;当壳层厚度小于针孔尺寸时,针孔弥散效应会显著降低峰值密度,利用维纳滤波法处理背光图像后密度反演的结果得到明显改善;相同针孔面积条件下,椭圆形针孔给出的峰值密度要低于圆形针孔的结果。     

Effect of plane-mirror installation errors on pointing errors in periscope-type satellite optical communication terminals

In a satellite optical communication system, the pointing error is an important factor that strongly influences the system performance. For periscope-type satellite optical communication terminals, installation errors of 45° plane mirrors in the coarse point apparatus (CPA) can lead to pointing errors. In this respect, we classify the installation errors of two 45° plane mirrors in the system and derive the corresponding ??transfer?? matrices to describe them. Furthermore, we establish mathematical models of the pointing error caused by installation errors of 45° plane mirrors. These models allow one to calculate and compensate the pointing errors in periscope-type satellite optical communication terminals. The results of our simulations show that the pointing errors vary with the elevation axis angle but do not depend on the azimuth axis angle. Compared to the side-angle error, the slope-angle error brings a larger pointing error. However, the mathematical model we developed allows one to compensate more than 99.9?% of the overall pointing error. The present work provides a theoretical basis for the design of periscope-type satellite optical communication terminals.     

Effect of geometry structure on critical properties

The effective-field renormalization group (EFRG) scheme is utilized to compute critical properties of the transverse Ising model (TIM) in a quantum-spin system. We distinguish differences between lattices of the same coordination number but of different structures and take effects of the first fluctuation correction into account. The improved results for the critical transverse field are obtained for several lattice structures even by considering the smallest possible cluster, which is in good agreement with series results.     

Effect of geometry on magnetization distortion in closed-circuit magnetic measurements

The effect of specimen geometry on magnetization distortion in closed-circuit measurements is reported in this letter. The degree of the distortion increases as the ratio of length to diameter (L/D) of specimen decreases, and the distortion can reduce the magnetization values as much as 42% when the applied magnetic field is 24 kOe and the L/D is 0.28. The type of magnetic material also affects the distortion. Although the phenomenon seems to be similar to the “image effect” that occurs in open-circuit measurements, reports of this effect in closed-circuit measurements have not been found in the literature. Further research effort, including 3D computer modeling, for understanding this magnetic phenomenon is underway and will be reported later.     

Wavefront reconstruction using iterative discrete Fourier transforms with Fried geometry

A new kind of wavefront reconstruction algorithm is proposed in this paper, which can estimate the wavefront from its orthogonal gradients at different sample points. We model the gradients measured by wavefront sensor with the Fried geometry. Iterative discrete Fourier transforms and the correspondent Fried inverse filter in spatial frequency domain are introduced. No special boundary control is required to process the boundary condition in this algorithm. The stimulation and the experimental results show that the new algorithm has strong capability to fit the wavefront and it is more available if the sample points are few.     

Effect of superthermal electrons on dust-acoustic Gardner solitons in nonplanar geometry

The properties of nonplanar (cylindrical and spherical) dust-acoustic solitary waves (DASWs) in an unmagnetized, collisionless three-component dusty plasma, whose constituents are negatively charged cold dust fluid, superthermal/non-Maxwellian electrons (represented by kappa distribution) and Boltzmann distributed ions, are investigated by deriving the modified Gardner (MG) equation. The well-known reductive perturbation method is employed to derive the MG equation. The basic features of nonplanar DA Gardner solitons (GSs) are discussed. It is seen that the properties of nonplanar DAGSs (positive and negative) significantly differ as the value of spectral index κ changes.     

Effect of local toroidal flow on double-tearing modes in cylindrical geometry

The effect of local toroidal flow (LTF) on double-tearing modes (DTMs) is investigated in cylindrical geometry using the reduced magnetohydrodynamics (RMHD) model. The results indicate that the LTF between the two rational surfaces is the dominant suppression effect on DTMs. The suppression effect is enhanced with the flow width increasing, and the DTMs become more stable with the increase of the shear of the LTF between the two rational surfaces. So, in the reversed shear magnetic field configuration, the local flow is driven between the two rational surfaces, which can effectively suppress the development of DTMs and maintain the high-performance state.     

Holographic particle image velocimetry: analysis using a conjugate reconstruction geometry

Holographic recording techniques have recently been studied as a means to extend two-component, planar particle image velocimetry (PIV) techniques for three-component, whole-field velocity measurements. In a similar manner to two-component PIV, three-component, holographic PIV (HPIV) uses correlation-based techniques to extract particle displacement fields from double-exposure holograms. Since a holographic image contains information concerning both the phase and the amplitude of the scattered field it is possible to correlate either the intensity or the complex amplitude. In previous work we have shown that optical methods to compute the autocorrelation of the complex amplitude are inherently more tolerant to aberrations introduced in the reconstruction process, Coupland, Halliwell, Proc. Roy. Soc. 453 (1960) (1997) 1066. In this paper we introduce a new method of holographic recording and reconstruction that allows a constant image shift to be introduced to the particle image displacement. The technique, which we call conjugate reconstruction, resolves directional ambiguity and extends the dynamic range of HPIV. The theory of this method is examined in detail and a relationship between the image and object displacement is derived. Experimental verification of the theory is presented.     

Effect of cavity geometry on the performance of a gyrotron

The effect of interaction cavity geometry on the gyrotron performance in terms of cold cavity parameters (Q value and axial electric field profile), Ohmic wall loss, start oscillation current and interaction efficiency are analyzed in detail in this article. The measurement of Q value and axial electric field profile is also performed for the cavities with different geometries by using non-destructive and perturbation techniques, respectively. Scattering matrix code is used for the computation of Q value and axial electric field profile and results are compared with the experimental data. A Particle-in-Cell code and a specific beam–wave interaction computation code based on generalized non-linear theory are used in the efficiency calculations. For all numerical and experimental analyses, the case of 42 GHz, 200 kW gyrotron is considered here.     

Effect of focusing geometry on the continuous optical discharge properties

We studied the effect of the laser beam focusing geometry on the continuous optical discharge (COD) properties. We used a full two-dimensional radiative gas-dynamic model for the COD, maintained by a vertical CO₂ laser beam in free air atmosphere, in the Earth's gravitational field. The model takes into account all of the factors that are of importance in laser-sustained plasma processes, and uses realistic quasi optics to describe the laser radiation propagation. Results are presented for the optical discharge parameters as functions of applied laser power and degree (f-number) to which the laser beam is focused.     

Abel Inversion of Rotating Plasmas

A new mathematical method is presented which allows a systematic construction of the radial profiles of emissivity, angular frequency, and temperature from a measured two-dimensional intensity distribution function I(λ, x) whose spectral part is determined by line shift and line broadening due the Doppler-effect. The suitability of the method is demonstrated by test calculations and application to experimental data.     

Effect of geometry of hydrodynamically cavitating device on degradation of orange-G

In this research work, we have carried out geometric optimization of different cavitating devices using degradation of orange-G dye [OG] as a model pollutant. Three different cavitating devices viz. orifice plate, circular venturi and slit venturi were optimized and the degradation of orange-G dye was studied. The optimization of all three cavitating devices was done in terms of fluid inlet pressure to the cavitating devices and cavitation number. The effect of pH and initial concentration of the dye on the degradation rate was also studied. The geometry of cavitating device (flow cross sectional area, perimeter, shape, etc.) was found to be an important parameter in getting the maximum cavitational effect using hydrodynamic cavitation. The cavitational yield of all three cavitating devices were compared on the basis of mg of total organic carbon (TOC) reduction per unit energy supplied. The slit venturi gives almost 50% higher degradation rate and cavitational yield among all three cavitating devices studied for the same amount of energy supplied.     

Effect of the geometry of workpiece on polishing velocity in free annular polishing

Base on Coulomb friction model, the workpieces with different geometry rotating in free annular polishing are simulated. From simulation, the following conclusions are drawn. The angular velocity of workpiece is higher than that of polishing pad if the ring rotates uncontrolled in free annular polishing. The circular workpiece can synchronize with polishing pad through controlling the rotation of ring, which depends on the radii of ring and workpiece, the friction coefficients of polishing pad-workpiece and ring-workpiece,and the angular velocity of polishing pad. The workpiece with sharp corner cannot contact with the ring contiguously, which causes the contact state changing and the angular velocity of workpiece fluctuating ceaselessly, and this type of workpiece should be controlled with clamp to rotate synchronistically with the polishing pad.     

Effect of errors on the efficiency of local active sound absorbers

Effect of errors of different origin on the efficiency of sound absorption by a local active absorber is investigated. Degradation of the efficiency of absorption because of the errors is shown to be minimal in the case when the controller does not detect the field of the secondary radiator. Estimates of admissible errors are presented. Several active absorber configurations in which the radiator does not affect the receiver are considered.     

Effect of source geometry on the line contour of reabsorbed radiation

A general relation is derived for the line contour of reabsorbed radiation as a function of the geometric parameters of a cylindrical source and of the optical density of the plasma. The relative intensity of the reabsorbed radiation which leaves the source along its longitudinal axis is also found. A numerical calculation is carried out for a line with a Doppler contour, and it is shown that the Ladenburg-Levi function is a particular case of the function H found in the present analysis. Recommendations are given for improving the accuracy of measurements of the line contour and the integral intensity of the spectrum.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 3, pp.69–71, March, 1972.