P-△效应下的核心筒侧移与箱基倾角的耦合关系

基于箱基设计的一些假设及其结构力学的原理,推导了核心单筒悬挂式建筑考虑核心筒P-△效应及在各种水平荷载下的侧移公式.算例表明,考虑P-△效应的核心筒侧移与箱基倾角的耦合关系是十分重要的.     

带填充墙钢框架结构抗侧力性能试验及理论研究

介绍了7榀钢框架及带填充墙钢框架结构的水平静力及低周反复加载试验。通过测试有墙和无墙钢框架试验模型在侧向力作用下的变形全过程,得到了墙体对钢框架结构强度和刚度的影响,了解了节点的破坏特征及墙体本身的工作性能,得到了有墙及无墙钢框架结构的滞回性能。试验中发现,填充墙体和钢框架之间的连接性能很好,墙体和框架可以共同工作。通过参数分析,给出了结构抗震弹性层间角位移的建议取值为1/350。在理论分析的基础上,提出了填充墙框架体系抗侧刚度简化公式,得到了试验结果的验证。     

工字形铝合金偏心压杆平面外稳定承载力研究

运用ANSYS软件对工字形铝合金偏心压杆平面外稳定承载力进行了研究,分别讨论初弯曲、残余应力和截面厚度偏差等缺陷对杆件平面外稳定承载力的影响,提出稳定系数曲面的概念,指出平面外稳定系数是相对偏心率e′和相对长细比λ的二元函数,在空间上为一连续的曲面。并对不同截面尺寸杆件的平面外稳定系数进行大量计算分析,以此为基础拟合出了平面外稳定系数曲面=f(λ,e′)的函数表达式,可供设计参考。     

地下室刚度对地下室抗震影响的研究

文章讨论了地震作用下地下室的质量与刚度的变化对地下室侧向位移的影响。结果表明:当地下室的质量大于第1层的质量,地下室的抗侧刚度是第1层的2~4倍时,能够有效地减小其侧移。当地下室的抗侧刚度大于第1层的4倍时,再增加刚度,对减小地下室的侧移的效果不很明显。     

The stability of a thin three-layered composite truncated conical shell containing an FGM layer subjected to non-uniform lateral pressure

This paper examines the stability of thin three-layered truncated conical shells containing a functionally graded (FG) layer subjected to non-uniform lateral pressure varying with the longitudinal coordinate. The material properties of the functionally graded layer are assumed to vary continuously through the thickness of the shell, and the variation of properties follows an arbitrary distribution in terms of the volume fractions of the constituents. Further, the fundamental relations for stability and compatibility equations of three-layered truncated conical shells containing an FGM layer have been obtained. These equations, ascertained via Galerkin’s method, have been transformed into a pair of time-dependent differential equations. Then, critical non-uniform lateral pressure has been conclusively obtained. This paper is the result of a detailed parametric study conducted to determine the influences of thickness variations in the FG layer, radius-to-thickness ratio, lengths-to-radius ratio, and the material composition and material profile index on the critical parameters of three-layered, truncated, conical shells. Finally, the results will be validated through the comparison of obtained values with those in the existing literature.     

自平衡深层平板载荷试验检测基桩侧阻力的误差分析

文章主要论述了自平衡法深层平板载荷试验原理,分析了应用自平衡深层平板载荷试验成果推算基桩侧阻力的误差来源,并通过工程实践验证了这种误差,对采用自平衡深层平板载荷试验验证基桩承载力的理论和实践有一定的指导意义。     

横向冲击载荷下的车身薄壁梁结构截面内力特性仿真分析方法

薄壁梁结构内力变化是车身结构碰撞分析中的重要特性。以几种常见的圆柱碰撞工况为例,应用一种基于壳单元有限元模型的薄壁梁结构截面内力特性计算方法,分析了横向冲击载荷下的结构内力响应特性。分析内容包括薄壁梁结构的截面内力和内力矩的变化、内力功率和能量传递特性等。研究表明,圆柱冲击结构和结构冲击圆柱两种基本碰撞类型的能量传递方式分别是扩散型和汇聚型,结构形式与载荷工况共同决定了主要承载方式和能量传递的主要途径。结构内力特性仿真分析揭示了薄壁梁结构碰撞响应的力学本质特征———载荷与能量变化特性,为车身结构设计分析提供了重要方法。     

Computational model of edge effects in graphene nanoribbon transistors

We present a semi-analytical model incorporating the effects of edge bond relaxation, the third nearest neighbor interactions, and edge scattering in graphene nanoribbon field-effect transistors (GNRFETs) with armchair-edge GNR (AGNR) channels. Unlike carbon nanotubes (CNTs) which do not have edges, the existence of edges in the AGNRs has a significant effect on the quantum capacitance and ballistic I-V characteristics of GNRFETs. For an AGNR with an index of m=3p, the band gap decreases and the ON current increases whereas for an AGNR with an index of m=3p+1, the quantum capacitance increases and the ON current decreases. The effect of edge scattering, which reduces the ON current, is also included in the model. This article is published with open access at Springerlink.com     

金刚石有序排列对锯片性能的影响

排布方式合理的有序排列金刚石锯片能明显提高锋利性,增加寿命。试验采用2片无序排列锯片和4片有序排列锯片切割混凝土,不同排布方式的锯片切割性能有很大的差异。介绍了有序排列锯片制作的工艺流程,并且从理论上分析了排布参数对切割性能的影响,提出横向间距和纵向间距是有序排列方式设计中最重要的两个参数。     

Nonvolatile Charge Injection Memory Based on Black Phosphorous 2D Nanosheets for Charge Trapping and Active Channel Layers

2D van der Waals atomic crystal materials have great potential for use in future nanoscale electronic and optoelectronic applications owing to their unique properties such as a tunable energy band gap according to their thickness or number of layers. Recently, black phosphorous (BP) has attracted significant interest because it is a single‐component material like graphene and has high mobility, a direct band gap, and exhibits ambipolar transition behavior. This study reports on a charge injection memory field‐effect transistor on a glass substrate, where few‐layer BPs act as the active channel and charge trapping layers, and Al₂O₃ films grown by atomic layer deposition act as the tunneling and blocking layers. Because of the ambipolar properties of BP nanosheets, both electrons and holes are involved in the charge trapping process, resulting in bilateral threshold voltage shifts with a large memory window of 22 V. Finally, a memory circuit of a resistive‐load inverter is implemented that converts analog signals (current) to digital signals (voltage). Such a memory inverter also shows a clear memory window and distinct memory on/off switching characteristics.