Research Progress and Prospect of Road Dust Suppressants

Road dust has great adverse effects on traffic quality,traffic safety,atmospheric environment quality,and human health.Therefore,with the continuous development of modern science and technology,the research of road dust suppressants is also progressing.To promote the rational application and development of road dust suppressants,the research progress and prospects of them are analyzed in this paper.It includes a basic overview of road dust suppressants,the main types,the usage and precautions,and the main development direction.It is hoped that this analysis can provide some reference for further research and development of road dust suppressants.

Dynamic analysis of spatial convergence of green total factor productivity in China's primary provinces along its Belt and Road Initiative

This paper focuses on China's primary provinces along its Belt and Road Initiative,measures and analyses the provincial green total factor productivity (GTFP) development by GML index based on SBM directional distance function,discusses the temporal evolution characteristics of spatial convergence of the provincial GTFP under multiple spatial weight matrices,and estimates the net effect of China's Belt and Road Initiative on the development gap of provincial GTFP by regression discontinuity.The research shows that the provincial GTFP is generally good while the internal gap is relatively large.There is spatial absolute βconvergence and condition βconvergence in provincial GTFP,and the convergence speed has been signifcantly accelerated since the construction of China's Belt and Road Initiative.The current low economy level and infrastructure allocation efficiency of primary provinces restrict the GTFP development,while government expenditure has promoted the GTFP development,trade between provinces and countries along China's Belt and Road Initiative is negative to GTFP.China's Belt and Road Initiative has significantly narrowed the gap of provincial GTFP development with the net effect of-0.016.

Order Exponential Evaluation Model for Road Traffic Safety in City Clusters

This study presents an order exponential model for estimating road traffic safety in city clusters.The proposed model introduces the traffic flow intrinsic properties and uses the characteristics and regular patterns of traffic development to identify road traffic safety levels in city clusters.Additionally,an evaluation index system of city cluster road traffic safety was constructed based on the spatial and temporal distribution.Then Order Exponential Evaluation Model(OEEM),a comprehensive model using order exponent function for road traffic safety evaluation,was put forward,which considers the main characteristics and the generation process of traffic accidents.The model effectively controlled the unsafe behavior of the traffic system.It could define the levels of city cluster road traffic safety and dynamically detect road safety risk.The proposed model was verified with statistical data from three Chinese city clusters by comparing the common model for road traffic safety with an ideal model.The results indicate that the order exponent approach undertaken in this study can be extended and applied to other research topics and fields.

压制空间非平稳地震勘探随机噪声的ROAD径向时频峰值滤波算法

径向时频峰值滤波算法是一种有效保持低信噪比地震勘探记录中反射同相轴的随机噪声压制方法,但该算法对空间非平稳地震勘探随机噪声压制效果不理想.本文研究空间非平稳地震勘探随机噪声,即各道噪声功率不同的地震勘探随机噪声,其在径向滤波轨线上表征近似脉冲噪声,在径向时频峰值滤波过程中干扰相邻道滤波结果.为了减小空间非平稳随机噪声的影响,本文提出一种基于绝对级差统计量(ROAD)的径向时频峰值滤波随机噪声压制方法.该方法首先根据径向轨线上信号的绝对级差统计量检测空间非平稳地震勘探随机噪声,然后结合局部时频峰值滤波和径向时频峰值滤波压制地震勘探记录中的随机噪声.将ROAD径向时频峰值滤波方法应用于合成记录和实际共炮点地震记录,结果表明ROAD径向时频峰值滤波方法可以压制空间非平稳地震勘探随机噪声且不损害有效信号,有效抑制随机噪声空间非平稳对滤波结果的影响.与径向时频峰值滤波相比,ROAD径向时频峰值滤波方法更适用于空间非平稳地震勘探随机噪声压制.

基于ROAD和小波收缩的MLEM低剂量CT重建算法

针对低剂量CT(Computed Tomography)重建图像质量退化的问题,提出一种基于小波收缩和绝对差值排序各项异性扩散的MLEM(Maximum Likelihood Expectation Maximization)低剂量CT重建算法。算法在每次迭代中首先采用MLEM算法对低剂量CT投影数据进行重建。由于各项异性扩散对噪声敏感,所以算法先对重建后的图像进行小波变换,再在更稳定的低频小波域进行基于绝对差值排序的各项异性扩散处理,对小波高频系数进行软阈值降噪处理。然后将降噪处理后的系数进行小波反变换,得到降噪后的图像。最后使用中值滤波对图像进行处理,从而消除脉冲噪声点。实验结果表明,与其他几种常用重建算法相比,该算法重建的图像信噪比更高,归一化均方误差更小,处理后的图像更清晰,即可以在抑制噪声的同时,较好地保持图像的边缘和细节信息。

The Belt and Road Initiative and International Industrial Transfer: Economic and International Implications

Theorists have discussed the Belt and Road Initiative relative to its political or policy implications, and world response to it has focused on analysis and commentary that assesses it geopolitically, with some even calling it a power play by China. Although the Belt and Road Initiative was proposed and has been promoted by China, it fundamentally is being developed within and adapted to laws of international industrial transfer and worldwide economic development trends, founding the initiative on universality and objectivity. The Belt and Road Initiative is an upgraded version or a new phase of the Go Out strategy adopted by the Chinese government to encourage Chinese enterprises to look abroad, which has been an important part of international industrial transfer. China is becoming a major output source in this new round of international industrial transfer, and the countries along the Belt and Road have become the major recipients. The new growth center of the global economy is likely to emerge along the Belt and Road, but the question of which countries in particular will take the lead in industrializing and accelerating economic growth through this industrial transfer will be decided in part through conditions such as development stage, technical maturity, cost level, and geographical location and in part through internal and external policy adjustment and choices made by the participating countries.

路特固(ROADGOOD)——中国路基材料的发展方向

路特固(ROADGOOD)材料作为一种高科技的路基材料,在我国道路建设应用工程中已取得良好的效果。用这种高科技材料取代传统材料,建设坚固耐用四通八达的国家公路网,将会给我国公路建设事业带来巨大的效益。

All roads lead to Rome——Direct cervical carotid artery access in carotid artery intervention

Carotid artery stenting (CAS) is an alternative treatment for patients with severe carotid artery stenosis, especially those with prohibitively high surgical risks.……

The Precise Order and Singular Directions of Meromorphic Functions

The rnemmorphic functions of positive order(both finite positive order and infinite order) are discussed.First,the precise order and type function are given by using the characteristic function.Then some singular directions are defined and their existence is proved.

ENTIRE SOLUTIONS OF HIGHER ORDER DIFFERENTIAL EQUATIONS WITH ENTIRE COEFFICIENTS HAVING THE SAME ORDER

In this paper,we consider entire solutions of higher order homogeneous differential equations with the entire coefficients having the same order,and prove that the entire solutions are of infinite lower order.The properties on the radial distribution,the limit direction of the Julia set and the existence of a Baker wandering domain of the entire solutions are also discussed.

The Belt and Road Initiative in China＇s Emerging Grand Strategy of Connective Leadership

As Chinese leaders endeavor to maintain the international environment aligned withtheir strategic aim of realizing the ＂＇dream of national rejuvenation, ＂＇ the remarkableincrease in China ＂s capabilities, coupled with uncertainty in the global economy and theambivalent attitude of the USA toward the international order, poses fresh challenges toBeijing＇s foreign policy. The present paper argues that a lexicographic preference for themitigation of the risk of pushback against China＇s core interests underpins the Belt andRoad Initiative. Pursuing a strategy of credible reassurance commensurate to the shift inthe distribution of power in China＇s neighborhood and globally, President Xi Jinping＇sadministration has been cultivating a form of connective leadership that commits Chinato the encapsulation of the Belt and Road Initiative for transregional connectivity intoits own national development strategy, generating an octroye, non-hegemonic, type ofinternational social capital and integrating the existing order without corroborating theposition of its founder.

Does China's Belt and Road Initiative Challenge the Liberal,Rules-Based Order?

Rising powers like China are frequently depicted as posing a significant challenge to prevailing,Western-designed norms of global governance.Unsurprisingly,Chinas Belt and Road Initiative(BRI)has been described as an assertive grand strategy bent on reconstituting regional or even global order with new governance ideas,norms and rules.Conversely,this paper argues that BRFs challenge to existing global norms will mostly be unintentional.Through an analysis of key policy documents,it demonstrates that the BRFs normative content is pro-market and pluralist,failing to attack or present anything like a systematic alternative to the existing liberal order.Nonetheless,aspects of BRFs implementation will challenge prevailing global governance norms,particularly those relating to investment,aid,and social and environmental protection-but mostly by accident,not design.This is due to the fragmented governance of BRI inside China.Accordingly,BRI will likely erode established norms without offering any coherent alternative.

Biologically Inspired Node Generation Algorithm for Path Planning of Hyper-redundant Manipulators Using Probabilistic Roadmap

This article describes a biologically inspired node generator for the path planning of serially connected hyper-redundant manipulators using probabilistic roadmap planners. The generator searches the configuration space surrounding existing nodes in the roadmap and uses a combination of random and deterministic search methods that emulate the behaviour of octopus limbs. The strategy consists of randomly mutating the states of the links near the end-effector, and mutating the states of the links near the base of the robot toward the states of the goal configuration. When combined with the small tree probabilistic roadmap planner, the method was successfully used to solve the narrow passage motion planning problem of a 17 degree-of-freedom manipulator.

投资便利化对中国对“一带一路”沿线国家OFDI区位选择影响研究

为了研究投资便利化对中国对“一带一路”沿线国家直接投资区位选择的影响,本文首先选取了宏观经济环境、营商环境、基础设施建设、金融服务效率、科学教育供给水平以及制度环境6个一级指标和38个二级指标,建立了测评投资便利化水平的指标体系,应用熵值法算得52个沿线国家在2007—2019年期间的投资便利化水平。接着,运用拓展投资引力模型和面板门槛模型,对投资便利化对中国对“一带一路”沿线国家直接投资区位选择的影响进行实证分析。然后,分别从“一带一路”倡议提出前后及不同投资动机视角进行异质性检验。最后,提出中国应积极推动有关投资便利化规则的多边和区域谈判,不断加深同沿线各国的投资便利化建设与合作,促使其投资便利化水平提高,助推共建“一带一路”高质量发展。

Fuzzy-second order sliding mode control optimized by genetic algorithm applied in direct torque control of dual star induction motor

The direct torque control of the dual star induction motor(DTC-DSIM) using conventional PI controllers is characterized by unsatisfactory performance, such as high ripples of torque and flux, and sensitivity to parametric variations. Among the most evoked control strategies adopted in this field to overcome these drawbacks presented in classical drive, it is worth mentioning the use of the second order sliding mode control(SOSMC) based on the super twisting algorithm(STA) combined with the fuzzy logic control(FSOSMC). In order to realize the optimal control performance, the FSOSMC parameters are adjusted using an optimization algorithm based on the genetic algorithm(GA). The performances of the envisaged control scheme, called G-FSOSMC, are investigated against G-SOSMC, G-PI and BBO-FSOSMC algorithms. The proposed controller scheme is efficient in reducing the torque and flux ripples, and successfully suppresses chattering. The effects of parametric uncertainties do not affect system performance.

DOA Estimation Based on Sparse Representation of the Fractional Lower Order Statistics in Impulsive Noise

This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive noise as α-stable distribution, new methods which combine the sparse signal representation technique and fractional lower order statistics theory are proposed. In the new algorithms, the fractional lower order statistics vectors of the array output signal are sparsely represented on an overcomplete basis and the DOAs can be effectively estimated by searching the sparsest coefficients. To enhance the robustness performance of the proposed algorithms,the improved algorithms are advanced by eliminating the fractional lower order statistics of the noise from the fractional lower order statistics vector of the array output through a linear transformation. Simulation results have shown the effectiveness of the proposed methods for a wide range of highly impulsive environments.

Distributed Containment Control of Networked Nonlinear Second-order Systems With Unknown Parameters

In this paper, we study the containment control problem for nonlinear second-order systems with unknown parameters and multiple stationary/dynamic leaders. The topologies that characterize the interaction among the leaders and the followers are directed graphs. Necessary and sufficient criteria which guarantee the control objectives are established for both stationary leaders(regulation case) and dynamic leaders(dynamic tracking case) based protocols. The final states of all the followers are exclusively determined by the initial values of the leaders and the topology structures. In the regulation case, all the followers converge into the convex hull spanned by the leaders,while in the dynamic tracking case, not only the positions of the followers converge into the convex hull but also the velocities of the followers converge into the velocity convex hull of the leaders.Finally, all the theoretical results are illustrated by numerical simulations.

Extremum of second-order directional derivatives

In this paper, the extremum of second-order directional derivatives, i.e. the gradient of first-order derivatives is discussed. Given second-order directional derivatives in three nonparallel directions, or given second-order directional derivatives and mixed directional derivatives in two nonparallel directions, the formulae for the extremum of second-order directional derivatives are derived, and the directions corresponding to maximum and minimum are perpendicular to each other.

Reference model based consensus control of second-order multi-agent systems

This paper deals with the consensus problem of multi-agent systems with second-order dynamics. The objective is to design algorithms such that all agents will have same positions and velocities. First, a reference model based consensus algorithm is proposed. It is proved that the consensus can be achieved if the communication graph has a spanning tree. Different from most of the consensus algorithms proposed in the literature, the parameters of the control laws are different among agents. Therefore, each agent can design its control law independently. Secondly, it gives a consensus algorithm for the case that the velocities of the agents are not available. Thirdly, the effectiveness of the input delay and the communication delay is considered. It shows that consensus can be achieved if the input delay of every agent is smaller than a bound related to parameters in its control law. Finally, some numerical examples are given to illustrate the proposed results.

3-D simulations of freak waves based on high-order spectral method

Three-dimensional ( 3-D) directional wave focusing is one of the mechanisms that contribute to the generation of freak waves. To simulate and analyze this phenomenon,a 3-D wave focusing model is proposed based on the enhanced high-order spectral method,which solves the fully nonlinear potential flow equations with a free surface within periodic unbounded 3-D domains. The numerical model is validated against a fifth-order Stokes solution for regular waves. Laboratory-scale freak waves are observed with wave components having equal amplitudes. Investigations of the appearance and propagation of freak-wave events in a 3-D open wavefield defined by a directional wave spectrum are then realized.