A Polarized Radiative Transfer Model Based on Successive Order of Scattering

Based on Successive Order of Scattering approach, a full Vector Radiative Transfer model （SOSVRT） for vertically inhomogeneous plane-parallel media has been developed. To overcome the computational burdens of convergence, a simple approximation technique by truncating scattering orders with a geometric series is used to reduce computational time. Analytical Fourier decomposition of phase matrix with three symmetry relationships and two mutual inverse operators have been implemented to further improve the computational efficiency. To improve the accuracy, a post-processing procedure is implemented to accurately interpolate the Stokes vector at arbitrary angles. Comparisons with the benchmarks for an atmosphere of randomly orientated oblate spheroids show excellent agreement for each Stokes parameter （within 0.1%）. SOSVRT has been tested for different atmospheric condition against RT3, which is based on doubling-adding method, and the results prove that SOSVRT is accurate and much more efficient in vector radiative transfer modeling, especially for optical thin atmosphere, which is the most common case in polarized radiative transfer simulations. SOSVRT is written in Fortran 90 and the code is freely accessible by contacting the author.

Differential Quadrature Method for Steady Flow of an Incompressible Second-Order Viscoelastic Fluid and Heat Transfer Model

The two-dimensional steady flow of an incompressible second-order viscoelastic fluid between two parallel plates was studied in terms of vorticity, the stream function and temperature equations. The governing equations were expanded with respect to a snmll parameter to get the zeroth- and first-order approximate equations. By using the differenl2al quadrature method with only a few grid points, the high-accurate numerical results were obtained.

Hall Effect on Peristaltic Flow of Third Order Fluid in a Porous Medium with Heat and Mass Transfer

We investigated the influence of hall, heat and mass transfer on the peristaltic flow of MHD third order fluid under long-wavelength and low Reynolds number approximation. The governing equations are solved analytically with the appropriate boundary conditions by using perturbation technique. The formula of velocity with temperature and concentration is obtained analytically as a function of the physical parameters of the problem.

Second-order two-scale computations for conductive radiative heat transfer problem in periodic porous materials

In this paper, a kind of second-order two-scale （SOTS） computation is developed for conductive-radiative heat trans- fer problem in periodic porous materials. First of all, by the asymptotic expansion of the temperature field, the cell problem, homogenization problem, and second-order correctors are obtained successively. Then, the corresponding finite element al- gorithms are proposed. Finally, some numerical results are presented and compared with theoretical results. The numerical results of the proposed algorithm conform with those of the FE algorithm well, demonstrating the accuracy of the present method and its potential applications in thermal engineering of porous materials.

Fourth-Order Compact Formulation for the Resolution of Heat Transfer in Natural Convection of Water-Cu Nanofluid in a Square Cavity with a Sinusoidal Boundary Thermal Condition

In the present work, we numerically study the laminar natural convection of a nanofluid confined in a square cavity. The vertical walls are assumed to be insulated, non-conducting, and impermeable to mass transfer. The horizontal walls are differentially heated, and the low is maintained at hot condition (sinusoidal) when the high one is cold. The objective of this work is to develop a new height accurate method for solving heat transfer equations. The new method is a Fourth Order Compact (F.O.C). This work aims to show the interest of the method and understand the effect of the presence of nanofluids in closed square systems on the natural convection mechanism. The numerical simulations are performed for Prandtl number ( ), the Rayleigh numbers varying between and for different volume fractions varies between 0% and 10% for the nanofluid (water + Cu).

A-site ordered quadruple perovskite oxides AA＇_3B_4O_(12)

The A-site ordered perovskite oxides with chemical formula AA＇3B4O（12）display many intriguing physical properties due to the introduction of transition metals at both A and B sites. Here, research on the recently discovered intermetallic charge transfer occurring between A-site Cu and B-site Fe ions in La Cu3Fe4O（12） and its analogues is reviewed, along with work on the magnetoelectric multiferroicity observed in La Mn3Cr4O（12） with cubic perovskite structure. The Cu–Fe intermetallic charge transfer（LaCu3（3＋）Fe4（3＋）O（12）→ LaCu3（2＋）Fe4（3.75＋）O（12）） leads to a first-order isostructural phase transition accompanied by drastic variations in magnetism and electrical transport properties. The La Mn3Cr4O（12） is a novel spindriven multiferroic system with strong magnetoelectric coupling effects. The compound is the first example of cubic perovskite multiferroics to be found. It opens up a new arena for studying unexpected multiferroic mechanisms.

Effects of Second-Order Sum-and Difference-Frequency Wave Forces on the Motion Response of a Tension-Leg Platform Considering the Set-down Motion

This paper presents a study on the motion response of a tension-leg platform(TLP) under first-and second-order wave forces, including the mean-drift force, difference and sum-frequency forces. The second-order wave force is calculated using the full-field quadratic transfer function(QTF). The coupled effect of the horizontal motions, such as surge, sway and yaw motions, and the set-down motion are taken into consideration by the nonlinear restoring matrix. The time-domain analysis with 50-yr random sea state is performed. A comparison of the results of different case studies is made to assess the influence of second-order wave force on the motions of the platform. The analysis shows that the second-order wave force has a major impact on motions of the TLP. The second-order difference-frequency wave force has an obvious influence on the low-frequency motions of surge and sway, and also will induce a large set-down motion which is an important part of heave motion. Besides, the second-order sum-frequency force will induce a set of high-frequency motions of roll and pitch. However, little influence of second-order wave force is found on the yaw motion.

Heat transfer analysis of Williamson fluid over exponentially stretching surface

This study explores the effects of heat transfer on the Williamson fluid over a porous exponentially stretching surface. The boundary layer equations of the Williamson fluid model for two dimensional flow with heat transfer are presented. Two cases of heat transfer are considered, i.e., the prescribed exponential order surface temperature （PEST） case and the prescribed exponential order heat flux （PEHF） case. The highly nonlinear partial differential equations are simplified with suitable similar and non-similar variables, and finally are solved analytically with the help of the optimal homotopy analysis method （OHAM）. The optimal convergence control parameters are obtained, and the physical fea- tures of the flow parameters are analyzed through graphs and tables. The skin friction and wall temperature gradient are calculated.

不同分数导数下Maxwell杂化纳米流体流动和传热变化的灵敏度分析

研究多孔介质中垂直拉伸板引起的分数阶Maxwell杂化纳米流体流动与传热现象,并考虑二阶滑移边界条件.利用分数阶剪应力和分数阶Fourier定律构建边界层控制方程.然后采用有限差分结合L1算法进行数值求解,并详细讨论分数导数参数增大时,各物理参数对该流体流动与传热影响的灵敏度变化.结果表明,Darcy数和滑移参数对平均表面摩擦系数的影响,以及滑移参数对平均Nusselt数的影响,对速度分数导数比对温度分数导数更敏感.Darcy数对平均Nusselt数的影响只对温度分数导数敏感,与速度分数导数几乎无关.此外,一阶滑移参数比二阶滑移参数对流动和传热的影响更大.

高接触比螺旋锥齿面修形方法及动态特性研究

为抑制高接触比螺旋锥齿轮传动的振动,提出一种新的高阶齿面修形方法。根据高接触比螺旋锥齿轮的啮合特点,提出一种新的修形曲线,采用辅助齿面修形方法生成高阶修形螺旋锥齿轮。在考虑齿变形的情况下,计算了高阶修正弧齿锥齿轮传动的载荷传递误差和啮合冲击,在此基础上建立了降低高接触比螺旋锥齿轮传动的载荷传递误差和啮合冲击的优化模型。仿真结果表明:与二阶修形弧齿锥齿轮相比,高阶齿面修形方法不仅可以有效降低高接触比螺旋锥齿的载荷传递误差、啮合冲击和动态负载系数,而且可以提高其在全速范围内的动态性能。

Viscoelastic Effects on Unsteady Two-Dimensional and Mass Transfer of a Viscoelastic Fluid in a Porous Channel with Radiative Heat Transfer

An analysis of oscillatory flow of a viscoelastic fluid and mass transfer along a porous oscillating channel with radiative heat transfer in presence of first-order chemical reaction is considered. The problem is concerned with the flow through a channel in which the viscoelastic fluid is injected on one boundary of the channel with a constant velocity, while it is sucked off at the other boundary with the same velocity. The two boundaries are considered to be in close contact with the two plates placed parallel to each other. The effect of temperature oscillations at the plate (upper wall) where the suction takes place is taken into consideration. The plates are supposed to be oscillating with a given velocity in their own planes. Analytical expressions for velocity profile, the temperature, concentration profile, wall shear stress on the upper wall are obtained. The profiles of the velocity and skin friction have been presented graphically for different values of the viscoelastic parameters with the combination of the other flow parameters encountered in the problem under investigation. It is observed that velocity decrease with the increasing values of the viscoelastic parameter in comparison with Newtonian fluid. Also, the wall shear stress increase with the increasing values of the viscoelastic parameter.

基于等效阻抗的分数阶RLC_(α)串联谐振BD-WPT系统传输特性分析

针对谐振式无线电能传输系统中分数阶电感、电容元件的仿真实现困难的问题,采用等效阻抗实现分数阶电容的等效.基于分数阶电容的阻抗特性,给出了一种分数阶RLC_(α)串联谐振双向无线电能传输(bidirectional wireless power transfer,BD-WPT)系统结构,通过建立含分数阶电容的串联谐振式双向无线电能传输系统的电路模型,推导了其传输功率和效率关系.仿真实验结果表明,与整数阶串联谐振系统相比,系统的输出功率提升了7.82%,传输效率提升了0.58个百分点.

Calculations of state-selective differential cross sections for charge transfer in collisions between O^(3+) and H_2

The non-dissociative charge-transfer processes in collisions between O^3＋ and H2 are investigated by using the quantum-mechanical molecular-orbital coupled-channel （QMOCC） method. The adiabatic potentials and radial coupling matrix elements utilized in the QMOCC calculations are obtained with the spin-coupled valence-bond approach. Electronic and vibrational state-selective differential cross sections are presented for projectile energies of 0.1, 1.0 and 10.0eV/u in the H2 orientation angles of 45° and 89°. The electronic and the vibrational state-selective differential cross sections show similar behaviours： they decrease as the scattering angle increases, and beyond a specific angle the oscillating structures appear. Moreover, it is also found that the vibrational state-selective differential cross sections are strongly orientation-dependent, which provides a possibility to determine the orientations of molecule H2 by identifying the vibrational state-selective differential scattering processes.

Synthesis of End Functional Polymers via Atom Transfer Radical Polymerization in Immobilized Catalytic System

Cross-linked polystyrene with azo-crown ether functional side chain (PSt-1, 10-dicarbonyl-3,6,9-trizaoeylcode-cane) was prepared under microwave irradiation and the structure was characterized through FT-IR and element analysis. The functionalized cross-linked polystyrene (cross-link degree, 3.5%) combining with immobilized catalyst system (CuBr and ethylα-bromo-isobutyrate) can catalyze atom transfer radical polymerization of Styrene. Neat polymer products can be obtained then. Complex of La and the polymer end group (EBiB) was synthesized. The third order nonlinear optical property of the polymer-La complex was investigated and the structure was also characterized by FT-IR and XPS.

Deep Transfers of p-Class Tower Groups

Let p be a prime. For any finite p-group G, the deep transfers T H,G ' : H / H ' → G ' / G " from the maximal subgroups H of index (G:H) = p in G to the derived subgroup G ' are introduced as an innovative tool for identifying G uniquely by means of the family of kernels ùd(G) =(ker(T H,G ')) (G: H) = p. For all finite 3-groups G of coclass cc(G) = 1, the family ùd(G) is determined explicitly. The results are applied to the Galois groups G =Gal(F3 (∞)/ F) of the Hilbert 3-class towers of all real quadratic fields F = Q(√d) with fundamental discriminants d > 1, 3-class group Cl3(F) □ C3 × C3, and total 3-principalization in each of their four unramified cyclic cubic extensions E/F. A systematic statistical evaluation is given for the complete range 1 d 7, and a few exceptional cases are pointed out for 1 d 8.

参数化流动传热问题的模型降阶方法研究

高精度的数值模型是构建反应堆堆芯数字孪生的基础,但传统的高分辨率数值模型的计算效率无法满足数字孪生的需求。为显著提高计算效率,综合利用伽辽金投影法和径向基函数插值法构造了参数化流动传热问题的降阶模型。该模型以典型的数值解作为学习样本,通过本征正交分解获得各物理场分布的主模态作为缩减基,然后将控制方程在缩减基张成的空间上进行投影以获得自由度个数显著降低的降阶模型。螺旋十字型燃料冷却剂的测试算例表明,相较于全阶模型,该降阶模型可实现高达3~4个数量级的加速效果,降阶模型的速度场与压力场的相对误差均小于10%。

高温升燃烧室热声耦合特性研究

为建立燃烧室热声不稳定性预测和分析方法,以某高温升单管燃烧室试验件为研究对象,构建了试验系统低阶热声网络(LOTAN)模型。基于试验数据,利用优化的方法获得了各工况下的火焰传递函数(FTF),并利用Kriging模型拟合出了增益与迟滞时间对工况参数的响应模型。利用拟合出的FTF响应模型分析了油气比和进气速度对燃烧室热声稳定性的影响。研究结果表明:通过优化得到的FTF能够较准确反映各工况下的非稳态热释放特性,导入LOTAN中计算得到的结果与试验结果吻合较好,最大误差约3.32%;油气比的改变会引起不稳定模态的转变,油气比或进气速度升高时,系统特征频率也随之升高。

分数阶粘弹性地基上裂纹梁的自由振动

本文研究了分数阶粘弹性Pasternak地基上含多裂纹Euler梁的自由振动问题.首先,引入分数阶导数概念,建立粘弹性Pasternak地基模型,推导出地基应力-应变本构的复模量以及地基反力.其次,将裂纹等效成无质量扭转弹簧,借助于裂纹能量释放率和应力强度因子的关系,推导出梁的局部柔度.然后,基于传递矩阵方法,建立含多裂纹梁的分段传递矩阵进而得到总体传递矩阵.最后,基于梁的边界条件,建立求解裂纹梁的复固有频率及振型的线性代数方程组,数值求解得到含多裂纹梁的固有频率及振型.以含双裂纹的两端简支Euler梁为例,数值计算了复固有频率和振型.并基于曲率模态分析裂纹位置对复固有频率和振型的影响.数值结果揭示了粘弹性地基的分数阶系数、粘性系数以及裂纹位置和裂纹深度对复固频率和振型的影响规律.

地铁车辆段上盖的全框支剪力墙结构设计探讨

根据地铁车辆段上盖全框支剪力墙结构设计实践,提出该结构按现行规范设计存在的问题,包括重力二阶效应验算,周期折减系数影响,框支柱剪力调整和厚板设计验算等问题。针对上述问题,建议重力二阶效应验算采用屈曲因子不小于20作为不考虑条件;少砌体墙的(框支)框架层考虑周期折减系数的影响,对(框支)框架层楼层剪力作折减;对于特一级或一级的框支柱的弯矩或剪力调整系数下调,避免调整后剪力远大于中震剪力的不合理情况;盖上剪力墙对厚板的冲切验算用作图法验算。

分数阶传递函数的SIMULINK实现

由于分数阶微积分具有"无限记忆"的特点,采用分数阶微分方程能够更全面准确的描述系统的动态特性。目前对于由分数阶传递函数所描述的分数阶系统的分析仿真主要是在MATLAB的工作空间中完成的,而不能如对整数阶系统的仿真分析可在SIMULINK环境下进行。基于分数阶微积分基本理论和SIMULINK模块封装技术,设计了一个可在SIMULINK环境下对分数阶传递函数进行显示、对分数阶系统进行分析的模块。该模块的调用与SIMULINK中整数阶传递函数模块的调用类似,具有便捷、直观的特点。通过工程实例验证,所设计的模块对分数阶系统的分析、设计可获得较好的效果。