Parameters to Define the Electron Beam Trajectory of a Double-Tapered Disc-Loaded Wideband Gyro-TWT in Profiled Magnetic Field

In the method of tapering the cross section of the interaction structure for broadbanding a gyro-TWT, the different portions of the interaction length of the tapered-cross-section waveguide become effective for different frequency ranges if the magnetic field and beam parameters are profiled to maintain the condition of electron cyclotron resonance throughout the interaction length. In the present paper, the study of profiling the magnetic field and beam parameters in steps of the stepped analytical model of a double-tapered disc-loaded circular waveguide was made throughout the steps of the model. In the observed profile, the magnetic flux density in a typical step relative to its value in first-step decreases from first-step (gun-end) to end-step (collector-end) of the model considering the up-tapering schemes, in which structure parameters increase from gun-end to collector-end. Also, the transverse beam velocity in a typical step relative to its value in first-step decreases from gun-end to collector-end. However, the Larmor radius in a typical step relative to its value in first-step as well as the hollow-beam radius in a typical step relative to its value in first-step, both increase from gun-end to collector-end in the model considering the up-tapering schemes.     

浅析影响康普顿谱线位置的因素

康普顿散射中影响康普顿谱线位置的因素是十分复杂的,文章主要针对影响康普顿谱线位置的几个因素作了理论探讨,得出影响因素主要在于:电子具有初速度会增大散射波长的改变量;束缚能的存在要减小峰值波长的改变量;双光子散射和二次散射与谱线峰值位置的关系不大,二者对峰值波长的改变是不确定的、复杂的、在连续的范围内变化的.最后对康普顿谱线位置和康普顿轮廓的理论研究和应用前景作了展望.     

基于多孔径闪烁的湍流强度廓线反演方法研究

以多孔径闪烁方法的理论为基础,分别讨论了孔径滤波函数和光谱响应函数对权重函数的影响.根据包括边界层项的Hufnagel-Valley 5/7模型得到的闪烁指数,采用奇异值分解法反演了垂直方向的湍流强度廓线,结果的量级介于10~(-15)~10~(-17)之间,并随高度的增加不断减小,在量级和趋势上与理论模型基本一致;同时结合Shack-Hartman的实际测量结果,反演了水平方向1 km传输路径上的湍流强度分布状况.水平方向反演结果的量级在10~(-14)~10~(-15)之间,随传播距离的变化趋势与实验场地的实际情况较为符合,随时间的变化趋势与合肥地区同期的统计结果基本一致.     

Numerical investigation of the effects of sluice spillway roof profiles on the hydraulic characteristics

There is a need for evolving hydraulically efficient roof profile of bellmouth for high head sluice spillways, as sluice roof is susceptible to cavitation damage. In this paper, formulation and development of a numerical model for simulating the spillway flow and its application to a sluice spillway are presented. The main focus of the simulation study is to apply the developed model to investigate the effects of sluice roof profile geometry on the pressure distribution, the discharge coefficient and the nature of flow regime within the sluice bellmouth. From the analysis of results for eight different roof profiles by varying the entry and exit angles of elliptic bellmouth transition, some important observations have been suggested, which are of practical relevance to hydraulic design engineers. The numerical model results are compared for one profile with physical model study. The simulated results are in close agreement with the measured values. Copyright © 2007 John Wiley & Sons, Ltd.     

Lowest Order Constrained Variational Calculation of Structure Properties of Protoneutron Star

We calculate the structure properties of protoneutron star such as equation of state, maximum mass, radius and temperature profile using the lowest order constrained variational method. We show that the mass and radius of protoneutron star decrease by decreasing both entropy and temperature. For the protoneutron star, it is shown that the temperature is nearly constant in the core and drops rapidly near the crust.     

The Effect of Blood Contained in the Samples on the Metabolomic Profile of Mouse Brain Tissue: A Study by NMR Spectroscopy

(1) Recently, metabolic profiling of the tissue in the native state or extracts of its metabolites has become increasingly important in the field of metabolomics. An important factor, in this case, is the presence of blood in a tissue sample, which can potentially lead to a change in the concentration of tissue metabolites and, as a result, distortion of experimental data and their interpretation. (2) In this paper, the metabolomic profiling based on NMR spectroscopy was performed to determine the effect of blood contained in the studied samples of brain tissue on their metabolomic profile. We used 13 male laboratory CD-1^® IGS mice for this study. The animals were divided into two groups. The first group of animals (n = 7) was subjected to the perfusion procedure, and the second group of animals (n = 6) was not perfused. The brain tissues of the animals were homogenized, and the metabolite fraction was extracted with a water/methanol/chloroform solution. Samples were studied by high-frequency ¹H-NMR spectroscopy with subsequent statistical data analysis. The group comparison was performed with the use of the Student’s test. We identified 36 metabolites in the brain tissue with the use of NMR spectroscopy. (3) For the major set of studied metabolites, no significant differences were found in the brain tissue metabolite concentrations in the native state and after the blood removal procedure. (4) Thus, it was shown that the presence of blood does not have a significant effect on the metabolomic profile of the brain in animals without pathologies.     

Instantaneous phase shifting arrangement for microsurface profiling of flat surfaces

Phase shifting interferometry is a well-established technique for non-contact surface profile measurement. Though phase shifting technique has many advantages, it is marred by a few inaccuracies due to the vibration and mechanical movement of the phase shifter itself. Significant amount of work is reported to theoretically compensate these error sources. But for a few works, prominent achievements have not been reported in eliminating these error sources in phase shifting interferometry. In this paper, a novel optical layout, in combination with instantaneous phase shifting interferometry is described. Experiments were carried out with this setup on a super mirror with a λ/20 surface roughness, to demonstrate the validity of the principle.     

非圆截面环流器等离子体对于高n理想磁流体气球模的最佳压强分布

本文假定等离子体局部压强梯度由理想磁流体高n气球模所限定,讨论了非圆截面环流器的最佳压强剖面。分析了椭圆及三角变形的效应,发现三角变形对提高稳定性很有利;q剖面对平均比压值及中心比压值都有强烈影响,而沿半径下降的q剖面对提高比压值很有利。     

Minimum-Time Travel for a Vehicle with Acceleration Limits: Theoretical Analysis and Receding-Horizon Implementation

A methodology is proposed to generate minimum-time optimal velocity profiles for a vehicle with prescribed acceleration limits along a specified path. The necessary optimality conditions are explicitly derived, allowing the construction of the optimal solution semianalytically. A receding horizon implementation is also proposed for the on-line implementation of the velocity optimizer. Robustness of the receding horizon algorithm is guaranteed by the use of an adaptive scheme that determines the planning and execution horizons. Application to a real-life scenario with a comparison between the infinite and finite receding horizon schemes provides a validation of the proposed methodology. This work has been supported in part by the US Army Research Office, Awards DAAD19-00-1-0473 and W911NF-05-1-0331. The authors thank an anonymous reviewer for his insightful comments regarding the results in Sect. 5.