Diagnosis of indirectly driven double shell targets with point-projection hard x-ray radiography

We present an application of short-pulse laser-generated hard x rays for the diagnosis of indirectly driven double shell targets. Coneinserted double shell targets were imploded through an indirect drive approach on the upgraded SG-II laser facility. Then, based on thepoint-projection hard x-ray radiography technique, time-resolved radiography of the double shell targets, including that of their near-peakcompression, were obtained. The backlighter source was created by the interactions of a high-intensity short pulsed laser with a metalmicrowire target. Images of the target near peak compression were obtained with an Au microwire. In addition, radiation hydrodynamicsimulations were performed, and the target evolution obtained agrees well with the experimental results. Using the radiographic images, arealdensities of the targets were evaluated.

A NEW APPROACH FOR THE COMPUTATION OF DOUBLE SYMMETRY-BREAKING TURNING POINTS

We will consider an extension of a direct method due to Griewank and Reddien for the computation of double symmetry-breaking turning points which arise in the two-parameter dependent nonlinear problem of the form f(x,λ,μ)= 0. The method proposed could produce an extended system which does not introduce the null vectors as variables, and could therefore reduce the computational effort and storage. One numerical example is presented to demonstrate that the method is efficient.

BIFURCATION OF SINGULAR POINTS NEAR A DOUBLE FOLD POINT INZ_2 -SYMMETRIC NONLINEAR EQUATIONS

We consider the bifurcation of singular points near a double fold point in Z2 -symmetric nonlinear equations with two parameters,where the linearization has a two dimensional null space spanned by a symmetric null vector and an ami-symmetric null vector. In particular, we show the existence of a turning point path and a pitchfork point path passing ihrough the double fold point and they are the only singular points nearby. Their nondegeneracy is confirmed. A supporting numerical example is also provided. The main tools for our analysis as well as the compulation are some extended systems.

Contact Force Distribution and Static Load-carrying Capacity of Large Size Double Row Four-point Contact Ball Bearing

Clearance not only affects the startup torque,rotation precision and stiffness of bearing,but also affects the load distribution,load-carrying capacity and life of bearing.A computational model in which the clearance of bearing is first included is presented for determining the contact force distribution and static load-carrying capacity of a double row four-point contact ball bearing which is subjected to the combined radial,axial and overturning moment loadings.The relation between the negative axial clearance and the contact force distribution is analyzed.The static load-carrying capacity curves are established,and the effects of the changes in negative axial clearance,curvature radius coefficient of raceway groove and initial contact angle on the static load-carrying capacity are analyzed.The results show that,with the increase in the absolute value of negative clearance,the maximum contact load decreases first and then increases.The clearance values in the range of 0.2 mme0 mm have little effect on the static load-carrying capacity of bearing.With the increase in the curvature radius coefficient of raceway groove and the decrease in the initial contact angle,the static load capacity of bearing decreases.

Effects of g-jitter and radiation on three-dimensional double diffusion stagnation point nanofluid flow

The unsteady double diffusion of the boundary layer with the nanofluid flow near a three-dimensional(3D)stagnation point body is studied under a microgravity environment.The effects of g-jitter and thermal radiation exist under the microgravity environment,where there is a gravitational field with fluctuations.The flow problem is mathematically formulated into a system of equations derived from the physical laws and principles under the no-slip boundary condition.With the semi-similar transformation technique,the dimensional system of equations is reduced into a dimensionless system of equations,where the dependent variables of the problem are lessened.A numerical solution for the flow problem derived from the system of dimensionless partial differential equations is obtained with the Keller box method,which is an implicit finite difference approach.The effects studied are analyzed in terms of the physical quantities of principle interest with the fluid behavior characteristics,the heat transfer properties,and the concentration distributions.The results show that the value of the curvature ratio parameter represents the geometrical shape of the boundary body,where the stagnation point is located.The increased modulation amplitude parameter produces a fluctuating behavior on all physical quantities studied,where the fluctuating range becomes smaller when the oscillation frequency increases.Moreover,the addition of Cu nanoparticles enhances the thermal conductivity of the heat flux,and the thermal radiation could increase the heat transfer properties.

Dynamic Multi-Attribute Decision-Making Method with Double Reference Points and Its Application

To better reflect the psychological behavior characteristics of loss aversion,this paper builds a double reference point decision making method for dynamic multi-attribute decision-making(DMADM)problem,taking bottom-line and target as reference pints.First,the gain/loss function is given,and the state is divided according to the relationship between the gain/loss value and the reference point.Second,the attitude function is constructed based on the results of state division to establish the utility function.Third,the comprehensive utility value is calculated as the basis for alternatives classification and ranking.Finally,the new method is used to evaluate the development level of smart cities.The results show that the new method can judge the degree to which the alternatives meet the requirements of the decision-maker.While the new method can effectively screen out the unsatisfactory alternatives,the ranking results of other alternatives are consistent with those of traditional methods.

Double coupled fixed point for multi-valued mixed increasing operators in ordered Banach spaces

In this paper, a new concept of double coupled fixed point for multi-valued mixed increasing operators is given and some new double coupled fixed point theorems for multi-valued mixed increasing operators in ordered Banach spaces are also given. These results extend and generalize some results of Huang and Fang.

DOUBLE HIGH ORDER S－BREAKING BIFURCATION POINTS AND THEIR NUMERICAL DETERMINATION

We consider double high order S-breaking bifurcation points of two-Parameter dependent nonlinear problems with Z_2×Z_2-symmetry. Because of the underlying symmetry we could propose some regular extended systems to determine double high order S-breaking bifurcation points. and we could also show that there exist two quadratic pitchfork bifurcation point paths passing through the point being considered.

“Double low-points” anomaly in daily variation of vertical component of geomagnetic field before the M_S8.0 Wenchuan earthquake

The ＂double low-points＂ anomaly in daily variation of vertical geomagnetic component was observed on May 9, 2008 at 13 geomagnetic observatories belonging to the geomagnetic observatory network center of China Earthquake Administration. These observatories distribute roughly on three belts with the intersection in western Sichuan. On May 12, three days after the anomaly appearance, the great Ms8.0 Wenchuan earthquake occurred. The ＂double low-points＂ anomaly in daily variation of vertical geomagnetic component is an anomalous phenomenon of regional geomagnetism, which does exist objectively. The possible cause is the change of extrinsic eddy current system resulting in geomagnetic daily quiet variation （Sq）, or the delay of several hours between the intrinsic and the extrinsic eddy current systems. The relationship between the ＂double low-points＂ anomaly of daily geomagnetic variation and the earthquake reveals that the former possibly reflects the accelerative alteration of earthquake gestation in the deep Earth.

Can PC-9 Zhong chong replace K-1 Yong quan for the acupunctural resuscitation of a bilateral double-amputee? Stating the “random criterion problem” in its statistical analysis

AIM: To present an inclusion criterion for patients who have suffered bilateral amputation in order to be treated with the supplementary resuscitation treatment which is hereby proposed by the author.METHODS: This work is based on a Retrospective Cohort model so that a certainly lethal risk to the control group is avoided.RESULTS: This paper presents a hypothesis on acupunctural PC-9 Zhong chong point, further supported by previous statistical work recorded for the K-1 Yong quan resuscitation point.CONCLUSION: Thanks to the application of the resuscitation maneuver herein proposed on the previously mentioned point, patients with bilateral amputation would have another alternative treatment available in case basic and advanced CPR should fail.

Evaluation of the Double Snap-Through Mechanism on the Wave Energy Converter’s Performance

Lower efficiencies induce higher energy costs and pose a barrier to wave energy devices'commercial applications.Therefore,the efficiency enhancement of wave energy converters has received much attention in recent decades.The reported research presents the double snap-through mechanism applied to a hemispheric point absorber type wave energy converter(WEC)to improve the energy absorption perfomance.The double snap-through mechanism comprises four oblique springs mounted in an X-configuration.This provides the WEC with different dynamic stability behaviors depending on the particular geometric and physical parameters employed.The efficiency of these different WEC behaviors(linear,bistable,and tristable)was initially evaluated under the action of regular waves.The results for bistable or tristable responses indicated significant improvements in the WEC's energy capture efficiency.Furthermore,the WEC frequency bandwidth was shown to be significantly enlarged when the tristable mode was in operation.However,the corresponding tristable trajectory showed intra-well behavior in the middle potential well,which induced a more severe low-energy absorption when a small wave amplitude acted on the WEC compared to when the bistable WEC was employed.Nevertheless,positive effects were observed when appropriate initial conditions were imposed.The results also showed that for bistable or tristable responses,a suitable spring stiffness may cause the buoy to oscillate in high energy modes.

EXTENDED SYSTEMS FOR MULTIPLE S-BREAKING TURNING POINTS IN Z_2×Z_2-SYMMETRIC NONLINEAR PROBLEMS

Making use of the Z2×Z2 symmetry,we could study the structure near multiple S-treaking turning points.In particular,we show that there exist two kinds of singular point path through double S breaking turning points and triple S bieaking turning points,one ts quadratic turning pornt path and one is quadratic pitch fork bifurcation point path.Some simple regular extended systems to corn pute double and triple S-breaking turning points are proposed.Numerical examples are also

On Fatou Type Convergence of Convolution Type Double Singular Integral Operators

In this paper, some approximation formulae for a class of convolution type double singular integral operators depending on three parameters of the type(T_λf)(x, y) = ∫_a^b ∫_a^b f(t, s)K_λ(t-x,s-y)dsdt, x,y ∈(a,b), λ ∈ Λ [0,∞),(0.1)are given. Here f belongs to the function space L_1( <a,b >~2), where <a,b> is an arbitrary interval in R. In this paper three theorems are proved, one for existence of the operator(T_λf)(x, y) and the others for its Fatou-type pointwise convergence to f(x_0, y_0), as(x,y,λ) tends to(x_0, y_0, λ_0). In contrast to previous works, the kernel functions K_λ(u,v)don't have to be 2π-periodic, positive, even and radial. Our results improve and extend some of the previous results of [1, 6, 8, 10, 11, 13] in three dimensional frame and especially the very recent paper [15].

An Analysis of Double Laplace Equations on a Concave Domain

In the investigation, the complex geometric domain is a concave geometrical pattern. Due to the symmetric character, the left side of the geometric pattern,?i.e.?the L-shaped region is calculated in the study. The governing equation is expressed with?Laplace?equations. And the analysis is solved by eigenfunction expansion and point-match method. Besides, visual?C++?helps obtain the results of numerical calculation. The local values and the mean values of the function are also discussed in this study.

Experimental study on the effect of wind on pointing accuracy of antenna structures

Wind loads have instantaneity and turbulence characteristics that will lead to pointing errors in antenna structures,and these errors cannot be ignored in high-frequency observations.Using the Tianma 65 m radio telescope(TMRT)as an example object,the pointing errors caused by wind loads are investigated using an accelerometer system.First,the resonant frequency range of the antenna structure is used for reference to acquire useful signals through the bandpass filtering method.Then,the direct current(DC)component of these signals is filtered out using the fast discrete Fourier transform method,and the baseline of the acceleration is corrected using the least-squares method.Finally,the acceleration integral is solved approximately using the discrete trapezoidal area method,and the structural vibration displacement of the antenna is determined using a double integral of acceleration.The pointing errors are then obtained based on the displacement relationship between the primary and subreflector surfaces.When the wind speed is 3.2 m/s,the antenna pitch angle is 61.7°and the wind direction angle is 80°,the generated pitch pointing error is 3.05'',and the azimuth pointing error is 1.14''.These results are consistent with those obtained via inclinometer measurements,thus validating the signal processing method and the pointing error calculation method proposed in this paper.The research methods and data analysis results reported here provide a basis for further wind-induced pointing error correction studies.

基于点云维度转换的双优化层手眼标定方法

为提高点云相机与机器人坐标转换精度,提出一种双层Levenberg-Marquardt优化(D-LM)算法标定点云视觉系统和机器人的手眼关系。根据点云成像特点提出采用同心圆标记物代替棋盘格标定板,推导出2D-3D维度转换的标记物中心提取算法。利用欧拉角变换正交化手眼矩阵旋转矩阵。此外,构建双层LM优化模型对手眼矩阵进行优化。通过自主搭建的机器人平台验证提出的手眼标定算法,并与传统Tsai-LM标定方法对比。实验结果是采用提出的D-LM方法标定出的手眼矩阵平均误差为0.89 mm,优于Tsai-LM(平均误差3.55 mm),表明D-LM方法能减少系统随机误差对标定结果影响,提升工业领域视觉机器人工作精度。

考虑能量转换装置可变效率的综合能源系统多目标优化调度

为了全面考虑综合能源系统的运行性能,提出一种计及能量转换装置可变效率的综合能源系统多目标优化运行方法。首先,对具有可变效率的能量转换设备运行特性曲线进行分段线性化处理。其次,建立以经济成本、碳排放量和综合能源利用效率为优化对象的多目标优化调度模型,并通过Charnes-Cooper变换解决综合能源利用效率目标的非凸非线性问题。最后,在求解该多目标模型时,运用规格化法平面约束法生成均匀分布的帕累托前沿,再采用改进熵权双基点法决策出折衷最优解。对修改的IEEE 33节点电网和8节点热网耦合的综合能源系统进行仿真分析。结果表明:优化后的模型和算法可以得到兼顾综合能源系统经济性、低碳性及高效性的优化运行方案,为决策者提供科学的决策参考。

基于地形差异的电子商务进农村政策效应实证剖析

推动县域经济发展是实现城乡融合发展和乡村振兴的有效途径。利用2013—2020年中国2419个县(市、区)的面板数据,采用多时点双重差分法,通过实证研究,分析了电子商务进农村综合示范县政策对县域经济的影响。结果表明:电子商务进农村综合示范县政策显著促进了县域经济增长,该政策效应存在显著的区域异质性,电子商务进农村示范县政策不仅在地形平坦地区表现出促进作用,同时在地形起伏度较大的山地,也显著促进经济增长。由此表明,政策通过数字普惠金融指数的促进效应和市场的拉动效应可以实现县域经济的增长。

“双碳”目标下双积分政策与碳排放管理衔接的研究与思考

汽车产业是我国工业发展和居民消费的支柱性产业,也是加快“双碳”战略目标达成的重点行业。目前,我国汽车产业碳排放管理工作处于起步阶段,在政策层面,以《乘用车企业平均燃料消耗量与新能源汽车积分并行管理办法》(下称“双积分政策”)为抓手,引导供给侧优化产品结构,助推汽车产业节能与新能源汽车发展。目前,双积分政策的燃料消耗量等考核指标未能直接反映碳排放量高低,以现有政策框架为基础,研究构建与碳排放挂钩的碳积分政策体系,对于下一步引导我国汽车行业实现低碳转型具有重要的现实意义。从政策、行业等层面分析了双积分向碳积分转型的必要性,对转型中可能面临的问题进行分析,同时提出相关解决思路,为政策制修订提供参考。

“双碳”背景下新型墙材检测关键技术与优化路径分析

随着“双碳”目标的提出,墙体材料行业发展面临前所未有的压力。新型墙体节能保温材料作为实现建筑节能降耗的关键,其质量和性能检测显得尤为重要。因此,在“双碳”战略背景下分析了建筑新型墙材检测的重要性,探讨了检测关键技术要点,并基于目前检测中存在的问题提出了优化路径。