一种新型混凝土管梁柱节点受力性能分析

提出了一种新型混凝土管梁柱节点——梁筋穿心式节点,借助ABAQUS软件,建立了混凝土管梁柱节点模型以及普通混凝土梁柱节点对比模型,进行竖向加载、单向水平加载和水平低周反复加载。研究得出管柱节点比普通节点竖向承载力高17.5%,水平承载力相差不多,低周反复加载下的位移-柱端荷载滞回曲线饱满度略差。     

电梯控制系统抗干扰设计及应用

在介绍电梯控制系统基本构成的基础上,讨论电磁干扰对电梯的影响及危害,分析电磁干扰产生的原因和机理,研究解决措施及抗干扰设计方案。给出了在电梯控制系统设计中相应的解决方案及注意事项。详述了相应的抗电磁干扰措施在电梯实际运行中的应用方法。     

高压输配电设备对数据中心的电磁干扰分析

介绍高电压输配电设备对数据机房的电磁干扰危害;列举相关国内外规范对机房电磁环境的要求;以某数据中心为例,结合测试数据介绍高压输配电设备对数据中心的影响。     

上游干扰作用下高层建筑迎风面风压双峰分布特征数值模拟研究

在上游建筑干扰作用下,受扰高层建筑迎风面部分测点表现出正负压交替出现的现象,对应风压系数概率密度函数呈双峰分布特征。采用大涡模拟技术对上述现象进行数值模拟研究,并将模拟结果与风洞试验结果进行对比分析,以验证其有效性。研究结果表明,上游施扰建筑两侧的尾流脱落旋涡可演变成交替作用于受扰建筑迎风面的涡团,这些涡团与背景来流共同作用,在建筑表面形成正负压交替出现的风荷载。针对风压双峰分布特征,建立风压信号混合分布模型,该混合模型由与正压成分对应的高斯分布模型和与负压成分对应的广义极值分布模型组成,模型中的位置参数、尺度参数和权重都对整体风压分布特征有显著影响。相关研究可用于非高斯风压信号的极值评估及建筑围护结构风致破坏机理的分析。     

不锈钢纤维填充聚丙烯导电塑料的屏蔽效能研究

导电塑料是防止电磁波污染的一种重要防护性功能高分子材料.研究不锈钢纤维填充聚丙烯导电塑料(SS/PP)的制备和影响屏蔽效能(SE)的因素.在30～1500MHz范围内测试,不锈钢纤维(SS)添加量对导电塑料的力学性能和屏蔽效果影响较大.当添加量为3～10v%时,屏蔽效能(SE)为20～30dB;当纤维含量分别为15v%和45v%时,屏蔽效能(SE)可显著提高到40～50dB和55～65dB,但同时加工性能下降,冲击强度降低.     

Differential interference contrast‐photothermal microscopy in nanospace: impacts of systematic parameters

Differential interference contrast‐photothermal microscopy (DIC‐PTM), as a promising tool for trace analysis of nonfluorescent compounds, suffered low sensitivity in nanospace especially for aqueous samples, due to the poor thermophysical property of water and the unoptimised configuration. To improve its performance, a five‐layer DIC‐PTM model is built and influences of different parameters on the photothermal signal are investigated. The initial phase shift φ₀ between two branches of the probe beam is found to be a key factor determining the detection sensitivity and response linearity: at a large φ₀ (≤π/2) both a high sensitivity and a good linearity can be achieved, while a high signal‐to‐noise ratio occurs at a small φ₀. The steady‐state photothermal phase shift φ_dc has little impact on the linearity, which, however, is greatly influenced by the range of periodic photothermal phase shift φ_ac. By introducing two coatings into a nanospace to confine the photothermal effect within and around the sample, the sensitivity can be enhanced from a few times to over 100 times. On an optimised DIC‐PTM configuration and chip structure, detection limit down to 10^?3 cm^?1 (or 40 molecules in a detection volume of 0.2 fL) was achieved in a 300‐nm‐thick nanospace. This work paves a way for optimising the DIC‐PTM and chip structure for sensitive detection of analytes in nanospaces.     

An orientation‐independent DIC microscope allows high resolution imaging of epithelial cell migration and wound healing in a cnidarian model

Epithelial cell dynamics can be difficult to study in intact animals or tissues. Here we use the medusa form of the hydrozoan Clytia hemisphaerica, which is covered with a monolayer of epithelial cells, to test the efficacy of an orientation‐independent differential interference contrast microscope for in vivo imaging of wound healing. Orientation‐independent differential interference contrast provides an unprecedented resolution phase image of epithelial cells closing a wound in a live, nontransgenic animal model. In particular, the orientation‐independent differential interference contrast microscope equipped with a 40x/0.75NA objective lens and using the illumination light with wavelength 546 nm demonstrated a resolution of 460 nm. The repair of individual cells, the adhesion of cells to close a gap, and the concomitant contraction of these cells during closure is clearly visualized.     

Phase‐shifting differential interference contrast microscope with Savart shear prism and rotatable analyser

A novel differential interference contrast microscope (DICM) is proposed in this research. It is constituted by inserting a Savart shear prism between the objective and sample of a polarising microscope having a rotatable analyser as the phase‐shifter, and it is with the ability to enhance image contrast using the principle of shearing interferometry. This letter is to introduce the configuration, interpret the interference patterns and present the experimental setup of the DICM. In addition, this letter is to display the experimental results from the uses of the setup; the results demonstrate the validity and ability of the DICM.     

轴向柱塞泵回程盘与滑靴间接触情况及碰撞干涉分析

轴向柱塞泵运行过程中回程盘与滑靴会产生碰撞干涉甚至出现回程盘崩裂和滑靴拉脱的现象。首先,通过对回程盘与滑靴的运动学特性和接触动能损失进行分析,得出影响碰撞干涉程度的因素;然后,通过ADAMS仿真分析,得出回程盘钻孔与滑靴颈部的接触规律和不同影响因素下碰撞干涉程度的变化规律;最后对奇偶柱塞数的柱塞泵进行仿真分析,得出回程盘钻孔与滑靴颈部接触时较为严重的碰撞干涉程度出现的原因,为回程盘结构优化提供参考依据。     

空心阴极真空电弧焊接的引弧机理及参数优化

针对现有真空电弧焊接技术引弧过程的各关键因素没有明确标准,大部分依据经验来调节各因素的数值等问题,对真空电弧焊接设备的引弧过程影响因素进行了研究。以快速建立电弧、得到稳定引弧电流为目的,从电弧建立的基本机理入手,对氩气流量、击穿电压、击穿距离以及钽管直径等引弧过程中各影响因素进行了逐一分析。使用自适应神经模糊推理系统(adaptive neural network based fuzzy interference system,简称ANFIS)模型建立引弧最优参数预测模型,使用氩气流量、真空度、击穿距离及钽管直径作为模型输入,预测击穿电压最优值。通过现场实验,验证和完善了理论研究以及本研究参数预测模型的预测性能。结果表明,使用本研究的预测模型得到的系统参数进行引弧实验,引弧电流稳定,符合工艺要求。