Event-triggered design for discrete-time nonlinear systems with control constraints

Nonlinear Dynamics - In order to solve the constrained-input problem and reduce the computing resources, a novel event-triggered optimal control method is proposed for a class of discrete-time...     

战略变革对企业绩效的影响分析 ——基于内部控制和外部竞争的调节

动态环境下的战略变革在企业发展过程中有着重要的地位,但实践中对于战略变革对企业绩效的影响还没有确定的结论.以制造业企业为研究对象,从理论上探讨战略变革对企业绩效的影响,并运用非线性回归模型深入挖掘内部控制和外部竞争在战略变革影响企业绩效过程中的调节作用.实证结果显示:战略变革对企业绩效的影响呈现显著的U型关系,内部控制和外部竞争对于战略变革和企业绩效的关系都有着显著的调节效应.研究结论可以为企业在多变的环境下更好地实行战略管理提供一定的经验证据和实施建议.     

Experimental and Theoretical Studies on the Rearrangement of 2‐Oxoazepane α,α‐Amino Acids into 2′‐Oxopiperidine β2,3,3‐Amino Acids: An Example of Intramolecular Catalysis

Enantiopure β‐amino acids represent interesting scaffolds for peptidomimetics, foldamers and bioactive compounds. However, the synthesis of highly substituted analogues is still a major challenge. Herein, we describe the spontaneous rearrangement of 4‐carboxy‐2‐oxoazepane α,α‐amino acids to lead to 2′‐oxopiperidine‐containing β^2,3,3‐amino acids, upon basic or acid hydrolysis of the 2‐oxoazepane α,α‐amino acid ester. Under acidic conditions, a totally stereoselective synthetic route has been developed. The reordering process involved the spontaneous breakdown of an amide bond, which typically requires strong conditions, and the formation of a new bond leading to the six‐membered heterocycle. A quantum mechanical study was carried out to obtain insight into the remarkable ease of this rearrangement, which occurs at room temperature, either in solution or upon storage of the 4‐carboxylic acid substituted 2‐oxoazepane derivatives. This theoretical study suggests that the rearrangement process occurs through a concerted mechanism, in which the energy of the transition states can be lowered by the participation of a catalytic water molecule. Interestingly, it also suggested a role for the carboxylic acid at position 4 of the 2‐oxoazepane ring, which facilitates this rearrangement, participating directly in the intramolecular catalysis.     

The single-polarization filter composed of gold-coated photonic crystal fiber

A single-polarization filter comprising a gold-coated photonic crystal fiber based on surface plasmon resonance is designed and investigated. The pattern matching and coupled polarization characteristics analyzed by the full-vector finite element method (FEM) and losses at 1,540 nm are achieved to 1,016.01739 dB/cm (x-pol core mode) and 33.81917 dB/cm (y-pol core mode). The crosstalk (CT) value of the 1,540 nm band is ?853.12653 dB for fiber length $L=1,000\mathrm{\mu }\text{m}$ and the bandwidth is 850 nm. The working wavelength of the filter ranges from 1,280 nm to 1,540 nm by varying the diameter of outer air holes ($d_1$), the diameter of inner air holes ($d_4$), the metal film thickness (t), as well as the liquid refractive index (n).     

“零被引专利”就没有价值吗?——“零被引专利”在科学论文中的应用分析

 分析前人对零被引的研究成果发现，"零被引"的定义可能存在一定的局限，即只考察同类数据库中的引用情况。分析CSTPCD 2009-2012年的科技论文与引文发现，期刊论文引用了大量的技术专利。存在专利数据库中的"零被引专利"在科技论文中却有较高的引用次数。以其中1件"零被引专利"CN 01134280.3为例，从技术内容解读、10篇施引文献及其内容分析，展示了该项技术发明影响的研究主题，并通过文献调研解析了该项研究成果的工业化应用。基于钱学森的"基础科学-技术科学-工程科学"理论，探讨了使用较高科技论文引用次数的"零被引专利"及较高专利引用次数的"零被引论文"定量分析技术科学的可能性。     

小波分析在证券分析中的应用

传统股市投资分析中的证券分析方法之一———MACD法 ,利用DIF的移动平均值以确定证券的买卖时机 ,存在着时滞性 ,对非平稳的股市信息分析不能及时、较好地刻画股市的基本变化趋势 .作者根据证券投资理论 ,建立了相应的证券投资分析数学模型 ,根据小波分析多尺度分析能力强的特点 ,利用小波分解提取反映股市基本变化趋势的低频信息 ,改进了传统分析方法 ,建立了改进后的数学模型Ⅲ .该模型求解方便 ,同时与实际模型较好地逼近 ,具有时效性 .此外 ,以路桥建设股票 14 0个交易日的DIF和MACD值作为原始数据 ,用Matlab作为工具进行计算 ,求解模型Ⅲ .结果表明 :与传统分析方法相比 ,从模型Ⅲ中能得到更多的买卖点信息 ,而且价差更大 ,效果显著 ,充分显示了小波分析在股市技术分析中的强大生命力     

激光等离子体2660紫外探针及干涉系统

成功地在六路高功率Nd玻璃激光装置上建立了2660紫外激光探针和适合紫外波段的Normaski干涉仪,首次将可见波长的连续激光应用于紫外干涉仪中靶成像调整和光路准直。利用该紫外光干涉仪,在铜柱状靶(φ500μm)上测量了厚等离子体中高达0.6n。的电子密度。