涂层/基体体系的界面应力分析

针对热防护涂层的承载特征,建立了涂层、基体体系的平面应变模型.以均匀应变差比拟热膨胀失配,基于最小功原理,推导了完整涂层/基体界面应力的级数解.分析结果表明,在自由端面附近,界面应力集中明显,其峰值达到了与涂层内拉应力相当的量级.涂层膨胀或收缩,界面正应力分别呈现压应力或拉应力状态,界面剪应力也发生方向交变.     

TEMPORAL CHARACTERISTICS OF DECAY OF LIGHT-INDUCED ABSORPTION IN PHOTOREFRACTIVE BaTiO3 CRYSTALS

We report the observations of the decay processes of light-induced absorption in one undoped and two Ce-doped BaTiO₃ crystals. Two decay times were found, they had not a strong dependence on intensity in our experiment. We present a model with two different shallow trap centers to explain the experimental results. The theoretical and experimental resales agree well with each other. The light-induced absorption coefficients and decay times corresponding to the two shallow levels are also given.     

5-[(3,5-二溴-2-吡啶)偶氮]-2,4-二氨基甲苯的晶体结构

5-[(3,5-二溴-2-吡啶)偶氮]-2,4-二氨基甲苯对铜和钴是高灵敏度和高选择性试剂,其单晶系P2₁/n空间群,晶胞参数α=11.477(5)Å、b=15.642(6)Å、c=8.311(4)Å、β=110.54(4)°,每个晶胞中有4个分子。     

一种正交对角化的磷虾群算法

针对磷虾群算法在处理高维复杂问题时,容易陷入局部最优、收敛速度慢、求解精度低等不足,提出了一种正交对角化的磷虾群算法.该算法根据适应度值排序分组磷虾群,通过正交对角化策略,吸收优质磷虾的经验,引导磷虾群寻优,同时兼顾"平凡"磷虾按常规方法寻优,从而提升了全体磷虾寻优能力,并保持了种群多样性.对标准测试函数的实验表明了该...     

自适应变速率MOAM技术的研究及其在数据通信中的应用

传统的M QAM抗干扰能力较差,若使用减小M的方法提高抗干扰力,又会降低频带利用率,本文提出一种自适应变速率M QAM系统,根据信道情况自动调整M值,并研究了该系统在无线移动瑞利衰落信道中的性能,其频带利用率大于等于3.2b/s/H z,远远高于一般系统的相应指标。     

武平县负氧离子浓度预报模型的建立及检验分析

选取2017年12月-2018年11月武平县城区站及梁野山站的实况资料,对负氧离子浓度与相对湿度、气温、雨量等气象要素的相关性进行分析;采用SPSS软件选取与负氧离子浓度相关性好的气象要素作为逐步回归方程的预报因子,建立最优预报模型;最后用2018年12月实况资料作检验分析,得出武平县负氧离子浓度模型预报效果好.武平县...     

Characterization of low-resistance ohmic contacts to heavily carbon-doped n-type InGaAsBi films treated by rapid thermal annealing

Carbon-doped In Ga As Bi films on In P:Fe(100)substrates have been grown by gas source molecular beam epitaxy(GSMBE).The electrical properties and non-alloyed Ti/Pt/Au contact resistance of n-type carbon-doped In Ga As Bi films were characterized by Van der Pauw-Hall measurement and transmission line method(TLM)with and without rapid thermal annealing(RTA).It was found that the specific contact resistance decreases gradually with the increase of carrier concentration.The electron concentration exhibits a sharp increase,and the specific contact resistance shows a noticeable reduction after RTA.With RTA,the In Ga As Bi film grown under CBr4 supply pressure of 0.18 Torr exhibited a high electron concentration of 1.6×10²¹ cm^-3 and achieved an ultra-low specific contact resistance of 1×10^-8Ω·cm²,revealing that contact resistance depends greatly on the tunneling effect.     

平面盘形凸轮机构系统的设计与基本尺寸的分析

凸轮机构是机械中一种常用机构,在自动化和半自化机械中应用非常广泛。随着计算机的普遍使用及其应用技术的发展,为凸轮机构系统的设计奠定了良好的基础。同时计算机辅助设计既提高了凸轮设计的精度,也使得凸轮机构中的基圆、滚子半径、平底倾斜角、中心距等基本尺寸的确定提供了合理的依据,而这也是凸轮机构运动学分析和设计计算中最基本的内容。