基于ARM的智能车间环境监测系统

针对传统工业环境监测设备存在灵活性差、效率低、模组孤立运行、未接入互联网等问题,通过研究基于ARM的智慧车间监测环境优化方案,实现车间设备与环境监测系统。在ZigBee网络构建的传感器网络的基础上,采用ARM处理器对车间中的各个执行传感器给出最优的决策判断,从而实现加工厂环境的各个传感器自主调优。结合Android应用开发,实现操作界面可视化以及远程操控,为不同车间的工作环境提供个性化监测系统。

基于ARM的物联网智能网关的设计与实现

为了将多种形式的物联网传感器网络数据接入到云服务器,提出一种基于ARM的物联网智能网关的设计方法,网关能够自动完成不同形式的传感器网络数据的采集,汇聚到智能网关之后,由智能网关实时做出简单的执行判断,并将数据转发到云服务器,云服务器根据人工智能策略做出决策和执行操作,再经由智能网关下达到各个执行器。物联网智能网关以ARM开发板作为主控制器,需要完成异构网的数据转换,传感网络的设备管理,传感器数据实时更新到LCD屏。提供了一种低成本、高功效的智能网关系统设计方案,系统设计整体性能稳定。

茶树精油的挥发性控制与应用研究

在常温条件下,茶树精油是一种具有芳香气味的无色液体,具有易挥发的特性。从延缓茶树精油挥发速度、茶树精油自然挥发速度、加快茶树精油挥发速度等三方面对茶树精油挥发性控制与应用进行阐述,为茶树精油的深入研究提供理论依据。

Effect of specimen size on energy dissipation characteristics of red sandstone under high strain rate

In this experiment, red sandstone specimens, having slenderness ratios of 0.5, 0.7, 0.9 and 1.1 respectively, were subjected to blow tests using a Split Hopkinson Pressure Bar(SHPB) system at a pressure of 0.4 atmospheres. In this paper, we have analyzed the effect of slenderness ratio on the mechanical properties and energy dissipation characteristics of red sandstone under high strain rates. The processes of compaction, elastic deformation and stress softening deformation of specimens contract with an increase in slenderness ratio, whilst the nonlinear deformation process extends correspondingly. In addition, degrees of damage of specimens reduced gradually and the type of destruction showed a transformation trend from stretching failure towards shear failure when the slenderness ratio increased. A model of dynamic damage evolution in red sandstone was established and the parameters of the constitutive model at different ratios of length to diameter were determined. By comparison with the experimental curve, the accuracy of the model, which could reflect the stress–strain dynamic characteristics of red sandstone, was verified. From the view of energy dissipation, an increase in slenderness ratio of a specimen decreased the proportion of energy dissipation and caused a gradual fall in the capability of energy dissipation during the specimen failure process. To some extent, the study indicated the effects of slenderness ratios on the mechanical properties and energy dissipation characteristics of red sandstone under the high strain rate, which provides valuable references to related engineering designs and academic researches.

孔隙率对混凝土力学性能及能量耗散的影响研究

为了探究海绵城市建设中孔隙率变化对混凝土材料力学性能和能量耗散的影响,设计了孔隙率分别为12%、15%、18%、21%的混凝土,并利用万能试验机对4种孔隙率混凝土进行单轴压缩试验,得到应力-应变曲线。试验结果表明:随着孔隙率的增大,混凝土的弹性模量、峰值应力、泊松比逐渐降低,峰值应变逐渐增大,混凝土的总吸收能和弹性能逐渐减小,耗散能呈现先减小后增大的趋势。

变量核分数次积分交换子在Morrey空间上的加权估计

利用分数次积分在L^p空间的性质,证明了当核函数Ω(x,z)满足一定条件时,带变量核的分数次积分算子与Lipschitz函数b生成的交换子T^b Ω,a是从L^p,k(ω^p,ω^q)到L^q,kq/p(ω^q)的有界算子,从而推广了以往非变量核的相关结果。

基于VOSviewer软件的关键词共现分析茶树精油研究热点

为了探究茶树精油的研究热点,本文对近年来茶树精油研究成果进行了系统分析。文章基于Web of Science核心数据库、中国知网(CNKI)、万方数据库和维普数据库所收录期刊文献,利用VOSviewer软件对2016-2022年茶树精油研究的关键词进行共现和可视化图谱绘制,共纳入759篇文献。研究结果显示,茶树精油的近年研究热点可归纳为3个主要方面,即茶树精油制备与质量评价、猪产业和蠕形螨睑缘炎治疗中的应用、药理与毒理研究。

Effect of a preload force on anchor system frequency

The interrelationship between preload forces and natural frequencies of anchors was obtained from the structure of an anchor and its mechanical characteristics. We established a numerical model for the dynamic analysis of a bolt support system taking into consideration the working surroundings of the anchor. The natural frequency distribution of the system under various preload forces of the anchor was analyzed with ANSYS. Our results show that each order of the system frequency varied with an increase in preload forces. A single order frequency decreased with an increase in the preload force. A preload force affected low-order frequencies more than high-order frequencies. We obtained a functional relationship by fitting preload forces and fundamental frequencies, which was in agreement with our theretical considerations. This study provides theoretical support for the detection of preload forces.

Experimental study on the mechanical properties of rocks at high temperature

The mechanical properties of marble, limestone, and sandstone as well as the stress-strain curve, the varying characteristics of the peak strength, the peak strain and elastic modulus were studied by using the MTS810 Rock Mechanics Servo-controlled Testing System under the action of temperatures rang- ing from room temperature to 800℃ . Results show that (1) the peak strength and elastic modulus of marble fluctuate at the temperature from normal to 400 ℃ ; and they decrease gradually over 400℃ . (2) With the rise of the temperature, the peak strength and elastic modulus of limestone show downward trend from normal temperature to 200 ℃ ; have little change from 200 ℃ to 600 ℃; and decrease sharply over 600 ℃ . (3) The peak strength of sandstone shows a downward trend while a little change for elastic modulus at normal temperature to 200 ℃ ; and from 200 ℃ to 600 ℃ , the peak strength of sandstone in- creases while a little change for elastic modulus; the peak strength and elastic modulus decrease rap- idly at the temperature over 600 ℃ . (4) The peak strain of limestone shows little change at normal tem- perature to 600 ℃ , however, the peak strain increases rapidly over 600 ℃; and for marble and sandstone, the peak strain decreases with the rise of the temperature from normal temperature to 200℃ , the peak strain increases rapidly over 200℃. The result can provide valuable references for the rock engineering design at high temperature.

分层充填沿空留巷瓦斯治理技术研究

为有效解决高瓦斯矿井瓦斯治理难的问题,以漳村矿26采区2605工作面为研究背景,通过分析已回采工作面安全开采影响因素,提出“分层充填沿空留巷+高抽巷”瓦斯治理方式,即在2605工作面运输巷实施分层填充沿空留巷,封堵采空区涌出瓦斯,避免向留巷内泄漏,通过高抽巷对涌出瓦斯进行抽采。根据载荷适应性原理和变形适应性原理,建立分层充填沿空留巷围岩力学模型,给出充填墙失稳的判别临界值,研究分层充填墙力学性能和留巷期间围岩及充填墙稳定性和高抽巷的瓦斯抽采效果。研究表明:分层充填墙的稳定性受分层厚度比和充填墙宽度影响,存在最优参数组合。而高抽巷瓦斯抽采效果随着远离沿空留巷呈现先增后减的变化规律。现场观测数据表明:采用上述瓦斯治理方式后,2605工作面上隅角瓦斯体积分数小于0.55%,分层充填沿空留巷内瓦斯体积分数低于0.5%,该方式能有效地进行瓦斯治理,实现高瓦斯矿井的安全开采。