Plastic Buckling of Cylindrical Shells Under Transverse Loading

Thick cylindrical shells under transverse loading exhibit an elephant foot buckling mode, whereas moderately thick cylindrical shells show a diamond buckling mode. There exists some intermediate geometry at which the transition between buckling modes can take place, This behavior is significantly influenced by the radius-to-thickness ratio and the material yield strength, rather than the length-to-radius ratio and the axial force. This paper presents a critical value at which the transition of buckling modes occurs as a function of the radius-to-thickness ratio and the material yield strength. The result shows that the circumferential wave number of the diamond buckling mode increases with decreasing wall thickness. The strain concentration is also intensified for the diamond buckling modes compared with the elephant foot buckling modes.     

刚体—柔性梁及末端质量系统的动力学分析

研究刚体一柔性粱带末端质量系统作大范围旋转运动时的动力学问题.采用于系统法建立考虑"动力刚化"效应的系统刚柔耦合动力学方程,并采用假设模态描述变形,将偏微分方程转化为常微分方程进行求解.文中给出了算例,比较刚体-柔性梁带末端质量系统与不带末端质量系统的动力学响应的差异.     

从修辞的角度分析新闻语篇的劝说性

新闻语篇作为大众语篇，在现代社会中扮演着重要的角色，是人们了解外在世界的重要媒介。借助古修辞的三种劝说模式分析新闻语篇的劝说性，有利于人们对新闻报道有更深入的了解和认识，从而更好的把握和运用信息、丰富生活。     

Molecular phylogenetic analysis of three groups of Asian epilachnine ladybird beetles recognized by the female internal reproductive organs and modes of sperm transfer

We determined partial sequences of the nuclear 28S ribosomal RNA gene (717 base pairs) and mitochondrial DNA NADH-dehydrogenase subunit 2 gene (535 base pairs) of 25 species of phytophagous ladybird beetles from Asia that comprise 16 species of the genus Henosepilachna and nine species of the genus Epilachna, and reconstructed the phylogenetic trees for each gene by the maximum parsimony and maximum likelihood methods. The estimated phylogenetic relationships were consistent with those obtained by the mode of sperm transfer and female internal reproductive system, and supported an earlier assumption that very similar elytral spot patterns of some sympatric members of epilachnine beetles evolved independently.     

相位调制型振荡场生化传感器的理论分析

基于对称金属包覆波导振荡场生化传感器,提出了相位调制方法及其理论分析.同时设计了一种应用Mach-Zehnder干涉实现相位调制的实验装置.理论分析表明：相位调制方法比光强调制具有更高的灵敏度和更大的折射率变化测量范围.     

Anurans of Turvo State Park: testing the validity of Seasonal Forest as a new biome in Brazil

The composition of the anuran community of Turvo State Park was compared with that of other localities of Mesophytic semideciduous Forest, aiming to test the hypothesis that localities situated nearest the Misiones nucleus support the new phytogeographic unit, known as Tropical Seasonal Forests Region. In total 32 amphibian species were recorded in the park area and surroundings: Anura, 30 native species and one exotic; Gymnophiona, one species. The ordination among the 20 localities of Seasonal Forest showed the formation of three groups with 45% similarity: group 1, composed of localities of south-eastern and central western regions; group 2, composed of the localities of the transitional portion with the Atlantic Forest sensu stricto and group 3, composed of the southern localities. The consolidation of the second group, which includes the occurrence of endemic species, supports the proposal of a new phytogeographic unit.     

土力学与基础工程教学演示仪器的研制和应用

针对土力学和基础工程中许多较为抽象的原理和现象,阐述了研制土力学与基础工程教学演示仪器的目的和意义.然后以土体主动和被动破坏演示仪为例,介绍了教学演示仪器的研制与实践过程,包括该仪器构造、功能、主动破坏及被动破坏模式的模拟方法,简要介绍了浙江大学已研制成功的其他6套土力学与基础工程教学演示仪器.     

农村社会工作助力乡村振兴的实践模式

以湖南武陵山片区2市（州）为范例,分析了农村社会工作助力乡村振兴的发展契机,探讨了专业社会工作参与农村社会服务的实践样本,摸索出农村社会工作助力乡村振兴的3个实践模式.一是在嵌入方式上,从单纯的服务嵌入到服务与体制的分层互嵌;二是在工作范式上,由补缺性社会工作转向发展性社会工作;三是在工作方法上,从依赖专业工作方法到专业方法与本土经验相结合.     

非线性非局域光格子中的高阶光学模式及其稳定性

讨论了非线性非局域光格子中奇、偶及其各类高阶光孤子的能流随传输常数的变化,特别讨论存在于非线性非局域光格子中的第三、第四扭转孤子的高阶光学模式,并从中分析了孤子振幅随格子调制深度p和线性非局域响应参数d的变化趋势.同时利用线性稳定性方法讨论它们的稳定性,结果表明,它们的不稳定范围有所扩大.由于光格子对全光控制技术有着潜在的应用价值,所以这些结果可以为未来全光控制技术提供最新的理论依据.     

利用单传声器分解和测量管道内的高次模式声波

利用数字声源信号可完全重复的特点,提出了通过单传声器对管道高次模式声波进行分解和测量的方法.阐述了此模式分解方法的基本原理,建立了相应的测试系统.通过试验测量,与传统的驻波管法相比较,验证了此方法的有效性.给出了一个典型的试验应用,对于口径为600mm的方形管道,在频率为500,1 000,2 000Hz时,对管中存在的高次模式声波进行测量和分解.此方法的特点是仅需要使用单个传声器进行测量,并提高了可分解的高次模式数量.