一种基于生理双向调节机制的协同进化算法

为了提高多参数寻优效果,基于人体生理双向协同网络调节机制,提出一种网络协同优化算法(NCEA).对应相应生理系统设计其体系结构,具体包括监控管理级、协同调节级和群体搜索级:监控管理级根据适应度和群体分布密度等信息,发送协同指令给协同调节级;协同调节级根据协同调节指令,基于生理调节规律实时调整各个搜索群体的交叉和变异概率因子和搜索群体之间的个体交换概率,以及辅助群体的个体均匀化;群体搜索级包括主搜索群体和辅助群体,其中辅助群体为主群体提供优良个体,并避免搜索陷入局部最优.最后采用两个典型的多维非线性函数,检验NCEA的搜索精度和收敛速度,并应用于一种非线性智能优化控制器.试验结果表明,与标准的遗传算法和一种改进的遗传算法相比,NCEA具有较快的收敛速度和搜索精度.     

径流调节对冰坝形成影响的初步探讨

在水资源开发利用中，年径流多年变化大、径流年内分配不均，是解决供需矛盾中一个十分突出的问题。特别是北方河流多、年变化很大。最大、最小年径流比值一般为3－7，最大的竟达14；至于径流年内分配的不均匀性则更为突出，以黑龙江流域为例，冬季径流量占全年径流量的比重仅为3—5％，有的还不到2％。为满足生产、生活供水需要，特别是水电站与工业用水，不得不靠修建一定的蓄水工程进行径流调节，解决冬、枯季径流偏小的问题。但是在一些受冰凌影响较大的河流上，特别是纬度较高地区的河流，不当的调大冬、枯季径流会促使冰坝的发生，以…     

A Voronoi-based spatial algebra for spatial relations

Spatial relation between spatial objects is a very important topic for spatial reasoning, query and analysis in geographical information systems (GIS). The most popular models in current use have fundamental deficiencies in theory. In this paper, a generic algebra for spatial relations is presented, in which (i) appropriate operators from set operators (i.e. union, intersection, difference, difference by, symmetric difference, etc.) are utilized to distinguish the spatial relations between neighboring spatial objects; (ii) three types of values are used for the computational results of set operations-content, dimension and number of connected components; and (iii) a spatial object is treated as a whole but the Voronoi region of an object is employed to enhance its interaction with its neighbours. This algebra overcomes the shortcomings of the existing models and it can effectively describe the relations of spatial objects.     

Effects of pre-strain and baking parameters on the microstructure and bake-hardening behavior of dual-phase steel

In a typical process, C-Mn steel was annealed at 800°C for 180 s, and then cooled rapidly to obtain the ferrite-martensite microstructure. After pre-straining, the specimens were baked and the corresponding bake-hardening (BH) values were determined as a function of pre-strain, baking temperature, and baking time. The influences of pre-strain, baking temperature and baking time on the microstructure evolution and bake-hardening behavior of the dual-phase steel were investigated systematically. It was found that the BH value apparently increased with an increase in pre-strain in the range from 0 to 1%; however, increasing pre-strain from 1% to 8% led to a decrease in the BH value. Furthermore, an increase in baking temperature favored a gradual improvement in the BH value because of the formation of Cottrell atmosphere and the precipitation of carbides in both the ferrite and martensite phases. The BH value reached a maximum of 110 MPa at a baking temperature of 300°C. Moreover, the BH value enhanced significantly with increasing baking time from 10 to 100 min.     

高速公路深路堑边坡应力及位移的有限元分析

为了研究山区高速公路深路堑边坡的稳定性问题,基于三维非线性应力及位移有限元计算,对边坡稳定性进行了数值分析,并与sarma法的计算结果进行了对比.结果表明,有限元法解决边坡问题可以起到其他方法不可替代的重要作用.     

Synthesis of amorphous SeP2/C composite by plasma assisted ball milling for high-performance anode materials of lithium and sodium-ion batteries

To promote substantially the performances of red phosphorous(P) anode for lithium and sodium-ion batteries, a simple plasma assisted milling(P-milling) method was used to in-situ synthesize SeP₂/C composite. The results showed that the amorphous SeP₂/C composite exhibits the excellent lithium and sodium storage performances duo to the small nano-granules size and complete combination of selenium(Se) and phosphorous(P) to generate Se–P alloy phase. It was observed that insid...     

MEEMD-DBA-based short term traffic flow prediction

Aiming at the problem that ensemble empirical mode decomposition(EEMD) method can not completely neutralize the added noise in the decomposition process, which leads to poor reconstruction of decomposition results and low accuracy of traffic flow prediction, a traffic flow prediction model based on modified ensemble empirical mode decomposition(MEEMD), double-layer bidirectional long-short term memory(DBiLSTM) and attention mechanism is proposed. Firstly, the intrinsic mode functions(IMFs) and r...     

基于约束跟随理论的消防无人机水枪喷嘴跟踪控制

利用无人机（Unmanned Aerial Vehicle，UAV）参与灭火是解决城市高层建筑消防问题的一种有效手段.针对无人机云台运动的控制问题，提出一种基于约束跟随理论的云台水枪喷嘴跟踪控制策略.根据高层建筑实际灭火需求，设计了云台水枪喷嘴两自由度驱动结构，采用Denavit-Hartenberg（D-H）方法对云台系统进行建模并由此完成云台运动学方程的建立.根据拉格朗日方程构建云台无约束动力学模型，把云台水枪喷嘴的期望轨迹作为约束，在不引入诸如拉格朗日乘数等任何变量或伪变量的情况下，基于Udwadia-Kalaba方程得到可以满足约束跟随需要的驱动转矩解析式，实现状态连续反馈控制，以达到水枪喷嘴轨迹跟踪的目的.为了减小跟踪误差，采用 Baumgarte 约束违约法进行稳定性处理，并在MATLAB/Simulink环境下对其轨迹跟踪控制进行仿真. 搭建以数字信号处理器（Digital Signal Processor， DSP）为控制核心的实验平台进行轨迹跟踪控制实验.仿真和实验结果表明，基于约束跟随理论的轨迹跟踪控制算法能够有效地完成跟踪任务并实现对期望轨迹的高精度跟踪.     

A hint from phosphine complex: The π back-bonding in cobalt-phosphorene composite enables enhanced electrocatalytic performance

Regulating the electronic structure of the metal electrocatalyst is fundamental for its performance optimizing. The electronic states of the active metal centers are highly dependent on their coordination environment, especially when bonding is formed. The π back-bonding can induce great electron density redistribution around metals, yet it is barely applied in electrocatalyst design. Herein we electrodeposited metallic cobalt on black phosphorus(BP)nanosheets, forming BP-Co with a unique π back...     

The effect of surface-free energy and microstructure on the condensation mechanism of water vapor

Obtaining high-water-yield drinking water in arid areas without consuming energy is still a global challenge.Since water vapor is ubiquitous, atmospheric water harvesting technologies are undoubtedly one of the most promising candidates. A typical water condensation process is analyzed in this paper(nucleation, self-growth,coalescence and sliding). The mechanisms of interactions between adsorbate and water vapor are discussed.The effect of surface-free energy and microstructure on water vapor co...