基于VB的球面网壳施工控制系统设计

根据球面网壳的施工特点,采用VB6.0编制了球面网壳施工控制系统。根据系统的数据特点,采用MicrosoftExcel作为数据库。使用OLE控件调用AutoCAD软件,绘制三维结构模型图。使用Image控件和Line控件设计工具栏。系统根据施工误差对施工时可能出现的问题进行预警,有利于提高球面网壳的施工质量。     

Influence of depth-thickness ratio of mining on the stability of a bedding slope with its sliding surface in concave deformation

In order to study the influence of depth-thickness ratio on bedding slope stability, whose sliding surface is flexural concave in shape under mining conditions, this paper aims to study the characteristics of deformation and damage of bedding sliding with depth-thickness ratios of 200:1, 150:1, 120:1, 100:1 and 50:1by adopting numerical simulation analysis software combined with laboratory-made ‘‘under the influence of mining variable sliding surface slope similar simulation test bed", and to propose identification methods for slope stability under the influence of mining. The results show that mining activities under the slope reduce slope stability. With a decrease in the mining depth ratio, the influence of mining on the slope increases gradually, and the damage to the slope gradually expands, the stability of the slope gradually reduces, fracture occurs on the slope toe and the central fissure gradually develops to the surface,and reaches slide threshold when the depth-thickness ratio is 50:1.     

基于SVG的矿用3.3kV静止无功动态补偿装置的研究

针对工作面供电系统电压波动大、功率因数低、线路损耗大、设备启动困难等问题,提出以SVG技术为核心的无功补偿技术路线,并介绍了一种基于SVG的矿用3.3 kV静止动态无功动态补偿装置的设计方案。工业性测试结果表明,该补偿装置响应速度快,补偿平滑准确,显著提高了工作面设备启动和运行时的功率因数,缩短了启动时间,提高了启动和运行电压的稳定性,有效抑制了谐波,并具有显著的节能效果。     

二次型单神经元自适应算法在电动机控制中的应用

针对直流电动机调速系统现有控制方法存在PID控制器参数固定而导致控制效果差的问题,提出了二次型单神经元自适应PID控制算法,即在加权系数的调整中引入二次型性能指标,通过计算控制律可以得到所期望的优化效果。Matlab仿真结果表明,该算法可改善控制系统的动态过程品质,降低超调量,缩短稳定时间,并且有一定的抗干扰能力。     

锚杆锚固质量无损检测数据的处理方法研究

以声波法为基础的无损检测技术已经逐渐取代传统的拉拔实验成为锚杆锚固质量检测的主要手段。随着锚杆锚固技术在各类土木工程中的应用日益增加,锚杆锚固质量无损检测数据处理方法的研究工作也越来越受到重视。本文在分析锚杆锚固质量无损检测原理的基础上提出了以Hilbert变换为基础的数据处理方法,并将该方法应用于实际工程中,验证了其可行性。     

A preliminary study on optimizing the heat treatment of high strength Al–Cu–Mg–Zn alloys

The design of critical aerospace alloys is primarily built on optimizing strength and ductility, both of which can be enhanced by controlling the alloying element additions as well as heat treatment conditions. The 7075 alloy is one such aerospace alloy. The main objective of this study was to optimize the 7075 strength. Several experimental alloys were prepared and tensile test bars were cast using an ASTM B-108 type permanent metallic mold. The as-cast samples were then solution heat-treated at 470 °C for times up to 48 h. The solution heat-treated bars were also aged in order to improve the alloy strength through precipitation hardening. Line scans for Mg, Cu and Zn were obtained from the various heat-treated alloy samples using an electron probe microanalyzer equipped with Energy Dispersive X-ray (EDX) and Wavelength Dispersive Spectroscopic (WDS) facilities. Peaks corresponding to the Mg, Cu and Zn concentrations in the as-cast samples disappeared after solution treatment, reflecting optimized homogeneity structures. The newly developed versions of the 7075 alloy displayed an ultimate tensile strength (UTS) of ∼1 GPa.     

Ethylthio-substituted sandwich phthalocyaninato europium (III) semiconductors for sensing NO2 and NH3: Effect of the extended π-conjugate systems on tuning the conductivity and sensing behavior

By using the π-conjugated phthalocyanine macrocycle as the versatile building block, a series of five sandwich-type ethylthio substituted phthalocyaninato europium complexes, namely double-decker Eu[Pc(SC₂H₅)₈]₂ (Pc-1), triple-decker Eu₂[Pc(SC₂H₅)₈]₃ (Pc-2), and their corresponding dimers, [Pc(SC₂H₅)₈]₂Eu₂[BiPc(SC₂H₅)₁₂] (Pc-1@Pc-1), [Pc(SC₂H₅)₈]₃Eu₃[BiPc(SC₂H₅)₁₂] (Pc-1@Pc-2) and [Pc(SC₂H₅)₈]₄Eu₄[BiPc(SC₂H₅)₁₂] (Pc-2@Pc-2), are synthesized and prepared into the solution-processed films by a simple quasi-Langmuir-Shäfer (QLS) method. Combination between the extending π-conjugated system in the longitudinal and transverse directions of Pc macrocycles and/or radical nature of Pc-1 unit among different semiconducting molecules result in unusually small energy gaps (0.345–0.91 eV). Consequently, all of the semiconductors exhibit excellent conductivities. Among these materials, the conductivity for the radical species Pc-1@Pc-1, Pc-1@Pc-2 and Pc-1 is about 3–4 times larger than that for the non-radical compounds Pc-2@Pc-2 and Pc-2. Moreover, the QLS films of five semiconductors take excellent linear responses for both oxidizing NO₂ (100–300 ppb) and reducing NH₃ (4–8.6 ppm). Respectively, the sensitivity (in % ppm⁻¹) gets increased in the order of Pc-1 < Pc-2 < Pc-1@Pc-1 < Pc-1@Pc-2 < Pc-2@Pc-2 for NO₂, and Pc-1@Pc-2 < Pc-1 < Pc-1@Pc-1 < Pc-2@Pc-2 < Pc-2 for NH₃. Depending on the highly extended π-conjugated systems, Pc-2@Pc-2 and Pc-2 films achieve the highest sensitivity of 208.2% ppm⁻¹ and 0.97% ppm⁻¹ to NO₂ and NH₃, respectively. In addition, with a less than 2 min response time within a limit of detection at 10 ppb for NO₂ and 0.48 ppm for NH₃, good reproducibility and selectivity have been revealed for the Pc-2@Pc-2 and Pc-2 films among the best gas sensors obtained so far for all the solution-processed films based on organic semiconductors in dry air at room temperature. More importantly, it is firstly demonstrated that the high NO₂ sensing is resulted from low Oxd₁, and high NH₃ sensing is resulted from high Red₁ among the sandwich Pc-based semiconductors.     

Development of slope mass rating system using K-means and fuzzy c-means clustering algorithms

Classification systems such as Slope Mass Rating(SMR) are currently being used to undertake slope stability analysis. In SMR classification system, data is allocated to certain classes based on linguistic and experience-based criteria. In order to eliminate linguistic criteria resulted from experience-based judgments and account for uncertainties in determining class boundaries developed by SMR system,the system classification results were corrected using two clustering algorithms, namely K-means and fuzzy c-means(FCM), for the ratings obtained via continuous and discrete functions. By applying clustering algorithms in SMR classification system, no in-advance experience-based judgment was made on the number of extracted classes in this system, and it was only after all steps of the clustering algorithms were accomplished that new classification scheme was proposed for SMR system under different failure modes based on the ratings obtained via continuous and discrete functions. The results of this study showed that, engineers can achieve more reliable and objective evaluations over slope stability by using SMR system based on the ratings calculated via continuous and discrete functions.     

平面转弯带式输送机技术方案浅析

主要介绍平面转弯带式输送机技术方案的设计计算及实现平面转弯的技术要点,保证托辊具有一定的安装支撑角,构成内曲线抬高角,增大成槽角,对线路进行合理设计,使普通带式输送机实现了平面转弯运行,并确定转弯半径和驱动功率,又用类比法对驱动装置进行了选型。具有良好的推广应用前景。     

Design and application of fiber Bragg grating (FBG) geophone for higher sensitivity and wider frequency range

The fiber Bragg grating geophone sensor with higher sensitivity and wider frequency range was reported. The methods to increase the sensitivity of the FBG cantilever sensor were presented. The acceleration sensitivity of the optimized FBG geophone is 220 pm/g, and the resonant frequency can reach to 295 Hz. The experiments show that the FBG geophone system has the minimum detectable acceleration of 1 mm/s². Some factual application examples of using this fiber Bragg grating geophone monitoring system for micro seismic monitoring in coal mine were presented.