Fixed-Order l_1-Control for Systems with Time-Delay

1. INTRODUCTIONPhysical plaaes are inevitably affected by exogenous disturbance, hence rejecting disturbanceis important. Ffor example, HOO-control systems can reject the LZ disturbance. But in factthere are maily species of disturbances: some are LZ-attenuation; some are stochastic; andsome are Loo(loo) [6]. If the exogenous disturbance is modeled as the energy-bounded signal, and the performance is the output energyt that is Hoo problem. If the performance isoutput energy, that is p…     

中小企业融资问题浅析

文章从分析中小企业内部和外部所存在的问题入手,提出了解决中小企业融资问题的途径,即必须从企业自身、银行体系和国家政策等多方面进行统筹考虑.     

作文教学两部曲

笔者经过积累与摸索,针对学生学语文,最怕写作文,而作文的优劣又决定着考试结果的好坏,对作文教学归结为"两部曲".     

Borg定理的改进

Borg定理是判定周期系数二阶线性微分方程稳定的一个重要工具,本文在弱的限制下改进Borg定理.     

一种基于旁信息增强的协同过滤自动编码器模型

针对用户评分预测不准确的问题,提出了一种基于旁信息(side-information)对用户兴趣进行预测的协同过滤自动编码器推荐模型,给出了模型的设计原理、损失函数以及具体结构.模型使用单隐藏层自动编码器实现,用户评分与旁信息同为模型的输入/输出数据,旁信息也直接参加模型的训练,这种设计不仅降低了模型的规模和复杂度,而且旁信息可以直接对用户兴趣进行修正.同时,通过对训练数据集合的合理划分与扩充,使得训练的网络模型增加了表达能力.在真实数据集上的对比实验表明,本文提出的方法提高了评分预测的准确度,具有一定的实用价值.     

Application-Oriented Performance Comparison of 802.11p and LTE-V in a V2V Communication System

In recent years, the Vehicle-to-Vehicle(V2V) communication system has been considered one of the most promising technologies to build a much safer and more efficient transportation system. Both simulation and field test have been extensively performed to evaluate the performance of the V2V communication system. However,most of the evaluation methods are communication-based, and although in a transportation environment, lack a V2V application-oriented analysis. In this study, we conducted real-world tests and built an application-oriented evaluation model. The experiments were classified into four scenarios: static, following, face 2 face, and crossing vertically, which almost covered all the V2V communication patterns on the road. Under these scenarios, we conducted experiments and built a probability model to evaluate the performance of 802.11p and LTE-V in safetyrelated applications. Consequently, we found out that improvements are still needed in Non-Line-of-Sight scenarios.     

MIL-101(Fe)对草甘膦的吸附行为研究

采用溶剂热法制备MIL-101(Fe)用作吸附材料,借助XRD、SEM、XPS及氮气吸脱附测试对所制材料的形貌及结构进行表征,研究了溶液pH值、反应时间、溶液浓度以及温度对其吸附草甘膦行为的影响。结果表明,当pH为3时,MIL-101(Fe)对草甘膦的吸附效果最佳,且随着温度的升高,MIL-101(Fe)对草甘膦的吸附速率明显增加,吸附过程符合拟二级动力学,等温吸附实验数据符合Langmuir和Temkin模型。MIL-101(Fe)吸附草甘膦属自发吸热的化学吸附反应,MIL-101(Fe)的中心金属Fe与草甘膦中O的配位在吸附过程中起主要作用。     

一类修正Hager-Zhang共轭梯度法的收敛性及其数值实验

为有效提高求解无约束优化问题的计算效率, 提出一类新的修正Hager-Zhang共轭梯度法, 该算法不依赖线搜索, 具有充分下降性和信赖域性质. 理论研究结果表明, 在常规假设条件下, 新算法不仅在弱Wolfe-Powell线搜索下对一般函数全局收敛, 且对一致凸函数具有R-线性收敛速度. 数值实验结果表明, 新算法比经典Hager-Zhang算法及其两个修正算法性能更优.     

原位纳米增强高强韧钢氢脆性能研究

We investigated the critical influence of in-situ nanoparticles on the mechanical properties and hydrogen embrittlement (HE) of high-strength steel. The results reveal that the mechanical strength and elongation of quenched and tempered steel (919 MPa yield strength, 17.11% elongation) are greater than those of hot-rolled steel (690 MPa yield strength, 16.81% elongation) due to the strengthening effect of in-situ Ti₃O₅–Nb(C,N) nanoparticles. In addition, the HE susceptibility is substantially mitigated to 55.52%, approximately 30% lower than that of steels without in-situ nanoparticles (84.04%), which we attribute to the heterogeneous nucleation of the Ti₃O₅ nanoparticles increasing the density of the carbides. Compared with hard TiN inclusions, the spherical and soft Al₂O₃–MnS core–shell inclusions that nucleate on in-situ Al₂O₃ particles could also suppress HE. In-situ nanoparticles generated by the regional trace-element supply have strong potential for the development of high-strength and hydrogen-resistant steels.     

强透水地层水平帷幕作用下基坑渗流特性

为研究强透水地层水平帷幕作用下基坑渗流特性,基于Darcy渗流理论,建立了水平封底帷幕作用下基坑渗流计算模型,推导出基坑内涌水量及帷幕底部水压的理论解,并通过室内渗流试验,验证了理论计算方法的可靠性.分析了渗透系数比、帷幕厚度以及帷幕与基坑底部的距离对基坑渗流的影响.研究结果表明:渗透系数比对渗流的影响起主导作用,当渗流系数比为0.01时,涌水量仅为不设帷幕的10％;帷幕厚度对渗流具有一定影响,而帷幕位置对渗流几乎没有影响.建议强透水地层基坑水平帷幕渗透系数比不宜高于0.01,厚度不宜小于4 m.