基于P-OTDR分布式光纤传感中信息提取的研究

在介绍了P＿OTDR分布式传感基本原理的基础上,深入研究了从测得的背向散射信号中提取出偏振态演化信息的方法.通过数字平均和解卷积提高了信号的信噪比和系统分辨率,为P＿OTDR分布式光纤传感系统的实用化提供了一定的基础.     

两多模相干态的叠加态光场的等幂N次Y压缩

根据量子力学态叠加原理,构造了由多模复共轭相干态|{zj(a)}>q和多模复共轭相干态的相反态等幂次|{-zj(b)}>q的线性叠加所组成的振幅不等的非对称两态叠加多模叠加态光场|Ψn(2)>q(j=1,2,3,…,q),利用多模压缩态理论研究了态|Ψn(2)>q的等幂次N次方Y压缩特性。结果表明:在各模的平均光子数不相等而对应模的初始相位相等亦即Rj(a)≠Rj(b)且ψj(a)=ψj(b)=ψj的条件下,如果各模的初始相位ψj和态间的初始相位差θpq(R)-θnq(R)=△θ满足一定取值关系,则无论压缩次数N为奇数还是偶数,态|Ψn(2)>q的两个正交相位分量均可分别呈现周期性变化的等幂次N次方Y压缩效应,但N是奇数时的压缩深度大于N是偶数时的压缩深度。     

非线性动态网络建立状态方程的系统方法

给出了非线性动态网络含非线性全电容回路、非线怀全电感割集建立状态方程的一种系统方法，该方法以网络拓扑为基础，导出的非线性动态网络状态方程具有一般形式，在非线性网络分析中具有较大的实用意义。     

灵魂在高处——郁达夫《故都的秋》解析

郁达夫的作品受争议较多,历年来一直有郁达夫作品难免颓丧消沉的评论。本文以《故都的秋》为例,解析了郁达夫精神世界当中的另一层面。看到他苦闷当中坚守的高尚情操,困境中仍不流于世俗的卓立精神以及对纯朴清淡的生活境界的真诚追求。     

列车轮轨黏着力在线估测计算方法

针对列车的制动防滑控制,提出黏着力的在线估测计算方法.因为黏着力不易测量,如何实时监测黏着力大小以便充分利用轮轨黏着是防滑控制的关键.建立了轮对动力学模型,并采用卡尔曼滤波器、扩张状态观测器等,以轴速和车轮等效夹紧力作为可输入量,设计了5种黏着力在线估测计算方法.采用Simulink软件平台,设置了信号噪声污染和传输延迟,并仿真了黏着力不变和黏着力变化两种工况,结果显示5种算法都能对黏着力进行估测,但综合黏着力估测的响应时间和最大误差两个指标来看,非线性扩张状态观测算法对黏着力的估测效果是最好的.最后,采用实测数据,进一步验证了算法对黏着力估测的准确性.     

REACTIONS IN SOLID STATE WITHIN POLYURETHANES. KINETICS AND POSTCURE REACTION MECHANISM IN CASTING POLYURETHANE ELASTOMERS

The solid state postcure reaction mechanism of polyurethane elastomers (PU) synthesized using a relatively small excess (up to 10%) of isocyanate was studied. The postcure process succeeds especially with the assistance of atmospheric humidity and, its process velocity depends on PU sample thickness. The polymer network is consolidated mainly by the formation of a new urea group. The formation of allophanate, uretidinedione, and isocyanurate groups and possible reticulations by the intermediary amine groups formed, play only a secondary role in the studied conditions. Kinetic equations regarding the postcure evolution were followed by means of the changes in mechanical properties. The evolution of the process was correlated to different kinetic measurements regarding the elementary processes involved like the consumption of NCO groups, absorption of water from the atmospheric humidity, and desorption of CO₂ resulted during the formation of urea group. The CO₂ desorption appears to be the slowest dynamic process.     

Dew Points of Binary Methane + Water: Measurement and Correlation

Experimental measurements of dew points for four methane + water mixtures between 2.6 2 10 5 Pa and 100.4 2 10 5 Pa and the temperature range from 225.5 K to 272.7 K were carried out. The experimental results were analysed in terms of both an equation of state model and an excess function-equation of state method, which reproduced the experimental data within AAD from 1.8 to 3.1 K and from 0.9 to 1.8 K, respectively.     

国家重点实验室建设的回顾与思考:1984-2008

改革开放三十年,国家重点实验室从无到有,从量的扩张到质的提升,为创新型国家建设做出了重大贡献。在分析国家重点实验室建设历程、现状及其成就与经验的基础上,提出了国家重点实验室未来发展的建议:创新管理体制;加大科研经费投入与提高经费使用效益并重;吸引、聚集、培养一流人才,致力于学术卓越;促进学科交叉与综合集成;建设优秀的实验室文化。