Adaptive Asymptotic Tracking Control for Stochastic Nonlinear Systems with Unknown Backlash-Like Hysteresis

In this study, an adaptive asymptotic tracking control problem is considered for stochastic nonlinear systems with unknown backlash-like hysteresis. By utilizing backstepping technology and bound estimation approach, an adaptive asymptotic tracking control scheme is designed, where fuzzy systems are applied to approximate unknown function terms, the effect of hysteresis and stochastic disturbances is compensated appropriately. The proposed scheme ensures that the tracking error can asymptoticall...     

Triazolotriazine-based thermally activated delayed fluorescence materials for highly efficient fluorescent organic light-emitting diodes (TSF-OLEDs)

Thermally activated delayed fluorescence (TADF) sensitized fluorescent organic light-emitting diodes (TSF-OLEDs) have shown great potential for the realization ...     

Parallel Optimization of the Crystal-KMC on Tianhe-2

The Kinetic Monte Carlo(KMC) is one of the commonly used methods for simulating radiation damage of materials. Our team develops a parallel KMC software named Crystal-KMC, which supports the Embedded Atom Method(EAM) potential energy and utilizes the Message Passing Interface(MPI) technology to simulate the vacancy transition of the Copper(Cu) element under neutron radiation. To make better use of the computing power of modern supercomputers, we develop the parallel efficiency optimization model for the Crystal-KMC on Tianhe-2, to achieve a larger simulation of the damage process of materials under irradiation environment. Firstly, we analyze the performance bottleneck of the Crystal-KMC software and use the MIC offload statement to implement the operation of key modules of the software on the MIC coprocessor. We use Open MP to develop parallel optimization for the Crystal-KMC, combined with existing MPI inter-process communication optimization, finally achieving hybrid parallel optimization. The experimental results show that in the single-node CPU and MIC collaborative parallel mode, the speedup of the calculation hotspot reaches 30.1, and the speedup of the overall software reaches 7.43.     

An MPI+OpenACC-Based PRM Scalar Advection Scheme in the GRAPES Model over a Cluster with Multiple CPUs and GPUs

A moisture advection scheme is an essential module of a numerical weather/climate model representing the horizontal transport of water vapor. The Piecewise Rational Method(PRM) scalar advection scheme in the Global/Regional Assimilation and Prediction System(GRAPES) solves the moisture flux advection equation based on PRM. Computation of the scalar advection involves boundary exchange, and computation of higher bandwidth requirements is complicated and time-consuming in GRAPES. Recently, Graphic...     

Cluster segmentation algorithm based on the Vicsek with static summoning points

Because of the low convergence efficiency of the ty-pical Vicsek model,a Vicsek with static summoning points(VSSP)algorithm based on the Vicsek model considerin...     

纤维素在ZnCl_2水溶液中的溶解性能及再生结构

比较了不同质量分数的ZnCl2水溶液溶解不同聚合度纤维素的能力,发现:质量分数为65.0%以下的ZnCl2水溶液不能溶解纤维素;当ZnCl2水溶液的质量分数达到或超过65.0%时,未被水分子饱和的Zn2+可与纤维素分子链作用,使纤维素溶解,且65.0%的ZnCl2水溶液的溶解效果最佳;随着纤维素聚合度的增大,其溶解性能下降;经ZnCl2水溶液溶解后的再生纤维素的聚合度下降.广角X-射线衍射(WAXD)分析表明再生纤维素为纤维素Ⅱ结晶变体;傅里叶变换红外光谱(FT-IR)显示ZnCl2水溶液是纤维素的非衍生化溶剂,且再生纤维素分子内的氢键减弱.     

热浸Zn-Ni-V合金镀层的氧化行为

研究了热浸纯Zn和Zn-0.05%Ni-0.05%V镀层在350℃下的恒温氧化行为。采用SEM、OM、EDS、XRD等方法分析了镀层氧化前后的表面、截面形貌及相组成。结果表明:Zn-0.05%Ni-0.05%V镀层可以有效地抑制Fe-Zn反应和ζ相层的超厚生长;350℃下氧化150h后,纯Zn和Zn-0.05%Ni-0.05%V镀层由ZnO和FeZn8.87两相组成;各镀层氧化动力学曲线主要为抛物线类型;在氧化过程中,纯Zn镀层形成大量的孔洞,氧化增重速率快,而Zn-0.05%Ni-0.05%V镀层组织较致密,具有更优的抗氧化性能     

基于G/G/1排队模型的802.11 DCF延迟分析

针对现有802.11 DCF分析模型在进行退避机制分析时不考虑周围节点状态的不足,提出了一种非饱和情况下IEEE 802.11 DCF协议的性能分析方法,推导出了以802.11 DCF为媒体访问控制(MAC)层协议的单跳无线网络中,MAC层的分组延迟及其抖动表达式,并分析了不同分组到达速率、节点数和退避窗口大小对MAC层分组冲突概率、延迟及其抖动的影响.仿真结果表明:MAC层的分组冲突概率、延迟及其抖动随着分组到达速率、节点数的增加而增加;以冲突概率的增加为代价,减小最小退避窗口可以减小MAC层的分组延迟及其抖动.     

船闸一次过闸平均吨位计算模型

为研究内河船闸通过能力,对其关键参量一次过闸平均吨位的计算方法进行改进,建立了基于船舶吨位与面积关系的一次过闸平均吨位计算模型.结合实测资料,对模型的船舶吨位与面积关系以及闸室利用率进行了分析.船舶吨位与面积关系可采用线性、二次多项式等函数进行回归分析得到,闸室利用率可采用其年平均值,一般在0.5~0.7之间.验证表明:该模型结构简单,能够得到令人满意的结果;较之规范(JTJ305—2001)推荐的方法,回避了过闸设计船型的选取及其组合等不确定性因素,能够动态地反映船舶大型化和标准化趋势的影响,根据实际或预测的船舶平均吨位即可连续计算一次过闸平均吨位,为船闸通过能力计算提供了新思路.     

化乐勘探区煤矿水文地质特征及充水因素分析

以化乐勘探区煤矿为例,对化乐勘探区煤矿的水文地质特征、含隔水层特征、地下水动态及含水层间的水力联系等因素进行分析,并分析了化乐勘探区煤矿的充水因素。