偏置式空间RSSR急回仿生扑翼机构优化设计与分析

本文基于偏置式空间RSSR四杆机构,设计了一种具有急回特性的扑翼机构,通过运动分析建立了空间RSSR四杆机构的运动学模型。以关节轴承处构件运动角和机构的压力角作为优化模型的非线性约束条件,摇杆摆角和行程比系数为目标函数建立了扑翼机构的优化设计模型。利用遗传算法对机构进行了优化计算,得到了利与飞行的相对杆长参数。基于优化得到的相对杆长参数以及鸟类飞行参数,选取曲柄长度为10 mm设计了一款仿生扑翼机构。结果表明:所设计的扑翼机构最小传动角y_(min)=40.01°,节轴承处构件运动角最大为60°,扑动上极限夹角ψ_(max)=21.92°,下极限夹角ψ_(min)=-18.11°,行程速比系数K=1.5与选取仿生鸟类飞行运动参数一致。

稀土功能材料的应用与展望

对稀土功能材料的应用进展进行了简要概述,介绍了稀土材料在发光材料、永磁材料、催化材料、储氢材料等重要领域的高值化应用情况,并展望了稀土材料在辐射防护、稀土合金等方面的研究新动向.

扑翼飞行器的凸轮摇杆型扑动机构设计与气动力学分析

为了提高扑翼飞行器的飞行性能,借鉴大型鸟类的飞行运动特征,设计了一种以凸轮摇杆为扑动机构的新型扑翼飞行器,建立了扑动机构的运动学和气动力学模型。结果表明:通过大型鸟类翅翼扑动规律对凸轮机构进行优化设计,得到了扑翼下扑占据整个扑动行程的60%左右;而提出的凸轮摇杆扑动机构的运动学模型,能够求解扑翼飞行器的相关运动参数。基于条带理论和扑翼飞行器的气动力模型,分别对凸轮摇杆扑翼飞行器、传统的双曲柄双摇杆机构扑翼飞行器的气动力进行计算比较,前者的平均升力为后者的1.382倍,前者平均推力为后者1.224倍,凸轮摇杆扑翼飞行结构具有更好的气动特性。

肝癌患者慢性应激的评价及其与患者预后相关性的初步研究

目的检测肝癌患者心率变异(heart rate variability,HRV)和应激指数水平,探索评估肝癌患者慢性应激水平的方法,初步探讨肝癌患者慢性应激状态与预后的相关性。方法收集41例肝癌患者,利用HRV检测仪分别在术后5 d,3、6个月检测患者应激指数和HRV指标R-R间期标准差(standard deviations of normal-to-normal R-R intervals,SDNN)、相邻R-R间期差值的均方根(root mean square standard deviations of R-R intervals,RMSSD)、低频功率(low frequency,LF)、高频功率(high frequency,HF)的水平;分析HRV各指标与应激指数的相关性;并研究各应激指标与患者生存时间的关系。结果 HRV 4个指标分别与应激指数呈显著负相关(SDNN、RMSSD、LF、HF的r分别为-0.703、-0.674、-0.508、-0.707,P<0.01)。应激指数和HRV指标分别与肝癌患者预后相关:应激指数高水平(≥52)的患者无疾病生存期和总生存期均较低水平组(<52)明显缩短(P<0.01)。HRV 4个指标SDNN、RMSSD、LF、HF低水平的患者无疾病生存期分别较高水平组短(SDNN、RMSSD,P<0.01;LF、HF,P<0.05)。4个HRV指标低水平组患者总生存期也较高水平组显著缩短(SDNN,P<0.05;RMSSD、LF、HF,P<0.01)。进一步分析发现应激指数和SDNN与肝癌患者术后复发情况明显相关(P=0.024,P=0.021)。结论 HRV水平较低的肝癌患者应激指数为高水平,这些应激指标能够评估患者慢性应激水平,证实慢性应激水平较高的肝癌患者术后复发率较高,总生存时间亦较短。

DEFORMATION MEASUREMENT OF CON-DUCTING POLYTHIOPHENE THIN FILMS BY AN ELECTRONIC SPECKLE PATTERN INTERFEROMETRIC METHOD

The deformation measurement of electrosynthesized polythiophene(Pth) thin films is difficult because of the small thickness and highflexibility of the specimen. An electronic speckle patterninterferom- etry (ESPI) method is used to measure the deformation ofPth films of thicknesses in the range of 4-65 μm . Theirstress-strain curves are obtained. It is found that the mechanicalproperties of Pth films are sensitive to the specimen thickness. Thetensile strength increases with decreasing thickness of thin filmfrom 10 μm. The influence of the electrochemical synthesisconditions on the mechanical properties of Pth films is also dis-Cussed.

EFFECT OF MONTMORILLONITE ADDITION ON MECHANICAL CHARACTERIZATIONS OF POLYIMIDE NANOCOMPOSITE FILMS

Tensile deformation and fracture characteristics of polyimide/montmorillonite nanocomposite films are investigated to enhance the particular mechanical properties and understand the effective factors in dominating the mechanical properties of nanocomposites, such as the nanolayer, matrix and nanolayer/matrix interface. How to contribute to the mechanical properties of nanocomposite film is a very complex problem. In this paper, these factors are analyzed based on the addition amount and fracture mechanics. The results indicate that the specimen at 20 wt% MMT breaks prematurely with a fracture strength （σb = 78 MPa） much lower than that （σb = 128 MPa） at the 1 wt% MMT. However, the Young＇s modulus （3.2 GPa） of the former is higher than that （1.9 GPa） of the latter. Fractography also indicates that the brittle cracking formed in high content addition is the main cause of failure but microscopically ductile fracture morphology still exists locally. And for the trace element addition, the smaller threading slipping veins are evenly distributed on the entire fracture section of these films. Therefore, these characteristics would presumably be associated with both the concentration effects of size of nanocomposite sheets and the increasing deformation harmony in nanolayers.

临床医学专业学位硕士研究生开展叙事医学课程的初步研究

目的建立一套科学合理的临床医学专业学位研究生叙事医学课程标准,提高临床医学专业学位研究生的医学人文素养。方法在查阅文献、小组讨论的基础上初步构建临床医学专业学位研究生叙事医学课程标准,采用Delphi法对指标进行评价筛选,然后拟定专家咨询问卷,对选取的40名专家进行专家咨询,最终确定叙事医学的课程标准。对重庆市西南医院肝胆外科在读研究生进行小范围教学实践,并收集了教学实施过程出现的各种问题。结果经过2轮咨询后,专家的意见趋于一致。最终确定由叙事医学导论理论课、叙事医学相关书籍的阅读、医学叙事影视作品的观摩、叙事医学病历的书写4个部分组成的理论和实践相结合的课程。通过小范围的教学实践,收集了教学实施过程中出现的各种问题,对问题进行整理与分析,并提出了改进方案。结论临床医学专业学位研究生叙事医学课程设置的构建合理,可为提升临床医学专业学位研究生的人文素养和医患沟通能力奠定基础,加快叙事医学理念在我国的普及进程。

An estimation method on failure stress of micro thickness Cu film-substrate structure

The failure of thin film-substrate structure occurs mainly at the thin film or the interface. However, the characterizing and estimating methods of failure stress in thin film are neither uniform nor effective because there are some complex effects of such as size, interface and stress state on the failure behavior of thin film-substrate structure. Based on the scanning electron microscope (SEM) in-situ in- vestigation on the failure models of the Cu thin film-substrate structure and the nano scratched testing results, the failure stresses in different thicknesses of the Cu film-substrate were characterized, which were compared and confirmed by other methods, such as Stoney formula and other empiric equations. These results indicate that the novel estimating method of failure stress in thin film based on the critical wavelength of surface unstable analysis is better than other methods. The main reason is that the novel estimating method of failure stress in meso thickness film fully considered the effect factors of free surface unstable behavior and elastic anisotropy of thin film. Therefore, the novel estimating method of failure stress assists people to understand the critical interfacial strength and to set up the failure criterion of thin film-substrate structure.

采用丝网印刷技术制备发光陶瓷并实现仿自然光照明

近年来白光LED照明技术广泛应用,但仍然存在散热差和蓝光过高的问题。以透明Al2O3陶瓷为基片,与多种LED发光材料、介质及基础釉料复合制作发光陶瓷。改变荧光粉的组成及发光层的厚度,可以调节发射光谱和发光效率。在此发光陶瓷的基础上,组装LED芯片,得到散热性好和仿自然光LED照明器件。此LED照明器件色温5127 K,色坐标为(0.3427,0.3654),显色指数Ra达到98,发光效率85 Lm·W^-1。