古代殿堂式木结构建筑模型振动台试验研究

对按照《营造法式》制作的古代殿堂式木结构建筑心间缩尺模型进行了模拟振动台试验研究。选用E l Centro波、Taft波、兰州波作为输入地震动。测量了台面、柱脚、柱头、木梁的位移和加速度响应。对模型的破坏形态、自振周期、阻尼比、动力响应、滞回耗能进行了分析。试验结果表明:自振周期T的变化范围为0.48~0.67s,阻尼比ξ的变化范围为0.029~0.046,模型的自振周期和阻尼比随着地震加速度的增强而增大;模型的动力放大系数β<1,且随着地震加速度的增强而减小;铺作层、柱础层都是通过摩擦滑移来耗能,柱架榫卯节点的耗能能力最强,在模型的耗能、减震中起着主要作用。     

Air Quality Prediction Based on Kohonen Clustering and ReliefF Feature Selection

Air quality prediction is an important part of environmental governance. The accuracy of the air quality prediction also affects the planning of people’s outdoor activities. How to mine effective information from historical data of air pollution and reduce unimportant factors to predict the law of pollution change is of great significance for pollution prevention, pollution control and pollution early warning. In this paper, we take into account that there are different trends in air pollutants and that different climatic factors have different effects on air pollutants. Firstly, the data of air pollutants in different cities are collected by a sliding window technology, and the data of different cities in the sliding window are clustered by Kohonen method to find the same tends in air pollutants. On this basis, combined with the weather data, we use the ReliefF method to extract the characteristics of climate factors that helpful for prediction. Finally, different types of air pollutants and corresponding extracted the characteristics of climate factors are used to train different sub models. The experimental results of different algorithms with different air pollutants show that this method not only improves the accuracy of air quality prediction, but also improves the operation efficiency.     

某大型火电厂主厂房钢框排架结构的弹塑性时程分析

为了研究大型火电厂主厂房钢结构框排架结构的抗震性能,对相似比为1/10的模型结构进行了拟动力试验.利用SAP2000软件对钢框排架进行了弹塑性时程分析,并与试验结果进行比较分析,两者吻合较好.研究结果表明:火电厂主厂房钢框排架结构在8度、9度罕遇地震作用下能满足变形要求,但结构存在较多的薄弱环节,在设计中应引起高度重视.     

Analysis on Extension Length of Shape Steel in Transfer Columns of SRC–RC Hybrid Structures

Seismic performance of SRC–RC transfer column was analyzed based on the experiment of 16 transfer columns specimens under low cyclic reversed loading, which mainly focus on the extension length of shape steel. Analysis of ductility, bearing capacity, energy dissipation capacity and degeneration ratio of strength were completed. Displacement ductility promotes at first and then reduces with increasing of extension length of shape steel, reaching the peak value when extension length gets close to three fifths of column height. Extension length of shape steel has little effect on bearing capacity, while energy dissipation capacity of transfer columns is influenced by many factors. Three fifths of column height is the rational extension length of shape steel, of which specimens have advanced in energy dissipation, good stability of stiffness and strength. The bond performance between concrete and shape steel decreases with the increasing of extension length of shape steel, and hence the stability of strength decreases. Minimum extension length of shape steel was confirmed and the calculation method was proposed, which is mainly used to ensure the bend yielding of shape steel at bottom section. Moment at the truncation section leads to pull-out effect of steel bars, which enhances with increasing of the moment and section ratio of shape steel. Contraflexure point is at three fifths of column height. If the shape steel extends to contraflexure point, moment of steel truncation section will reach minimum. So the reduce the concrete damage with better deformation ability and mechanical behavior of transfer column.     

A Permutation-Based Approach for Solving the Job-Shop Problem

In this paper, we deal with the famous job-shop scheduling problem, which has been being a constant subject of study for many years due to its high computational complexity (NP-hard in the strong sense). We present a permutation-based scheme for solving the problem, which in the abstraction level differs from the classical one of Jacques Carlier and Eric Pinson. In particular, we specify the differences both in the fashion of stating the constraints (the use of the generalized sorting constraint) and in the search strategy (splitting intervals of task orders). We will first give a constraint program for solving the problem, which involves only primitive constraints and which is clean and simple to understand. We then study some special techniques based on testing variable bounds that allow us to solve two hard instances la21 and la38. These two instances have been open problems recommended in a paper of David Applegate and William Cook in 1991.     

Design of a double-layer high transmittance broadband graphene absorbing metamaterial

In this paper, an optically transparent broadband absorbing metamaterial is designed for electromagnetic protection and stealth for visible parts of ships. Based on the coupling resonance loss of double-lay metamaterial structure, the new absorbing material realizes broadband characteristics. Based on the photoelectric compatibility characteristics of graphene thin films, the new absorbing material realizes high transmittance characteristics. The measured results show that when the absorbing rate is higher than 90%, the bandwidth of the absorbing metamaterial is 7.95—18.65 GHz, covering X-band (7.95—12 GHz) and Ku-band (12—18.65 GHz), and the visible light transmittance is 85%. The design and preparation of new absorbing material can solve electromagnetic compatibility (EMC) design problems of high transmittance and broadband. It can be widely used in observation windows of ships, aircraft and reconnaissance control vehicle, display terminal of the information system.     

人工智能背景下的中医舌诊客观化研究概述

为了促进中医舌诊的标准化和客观化,推动中医舌诊客观化研究,探究以深度学习为代表的人工智能技术在舌诊客观化领域的应用现状和研究水平,文章以舌像的采集-预处理-图像识别-客观诊断为主线,对舌像辩证自动化的新方法进行了归纳和总结。通过方法综述,为智能化舌诊和中医现代化研究提供方法参考和研究思路,促进人工智能技术在中医舌诊领域的深度发展。     

一种适用于星地网络的流量负载均衡算法

在星地网络的背景下,为了降低由于地面网络链路负载过高导致的传播时延,提出了一种适用于星地网络的负载均衡算法。算法基于网络的链路容量设置一个链路资源利用率作为阈值,当发现路径出现过载的时候分成两步进行路径的预规划：第一步,运用蚁群算法为链路过载的数据流选择其他的路径,以满足地面网内部的负载均衡;第二步,如果仍出现链路超阈值的情况,通过卸载延迟容忍数据流来执行地面与卫星网络之间的负载均衡。仿真结果表明,设定自适应的过载阈值可以有效降低链路的拥塞,与现有算法相比该算法不仅可以更加均匀地分配地面网络中的流量,而且借助卫星网络使地面网络的平均时延降低了18.3%,提高了网络的服务质量。     

Design of a novel spatial micro-gripper for manipulating irregular shape micro objects

Microsystem Technologies - A novel spatial micro gripper for manipulating different size and irregular shape objects was presented. Two clamping links are mutually vertically placed in order to...     

基于变权重因子差分进化算法的梯级水火电力系统调度

梯级水火电力系统的复杂性导致其调度优化问题难以使用经典的优化方法进行解决。本文通过变权重因子改进差分进化算法,提出新的方法解决其调度优化问题。采用启发式策略解决优化问题中的平衡约束。为了充分发挥能耗较低的火力发电机作用,设计基于优先列表的启发式策略,解决动态电力平衡约束。在满足平衡约束条件的过程中,部分个体的取值被改变,增加了群体的 多样性,拓展了算法的搜索空间,进而得到更优的调度解决方案。仿真结果表明,本文提出的方案有效地解决了梯级水火电力系统的调度优化。