基于性能的沥青路面全寿命设计方法--重交通沥青路设计方法之二

鉴于传统的路面结构设计不能很好地控制路面损坏状况 ,故对先前建立的路面结构行为方程进行了验证 ,分析了不同沥青材料对路面长期使用性能的影响 ,建立了旧路面的结构状况对罩面路面结构的影响关系 ,在此基础上对路面结构的全寿命使用性能进行了分析 .根据所建立的全寿命路面结构行为方程 ,提出了一套基于路面使用性能的新的路面设计方法 ,并试图根据路面在整个分析期内的使用性能来设计路面的结构组合 ,给出最优的、唯一的路面结构厚度组合 .为了保证按上述方法设计的路面结构具有期望的寿命 ,最后给出了路面材料选择的原则性建议     

沥青路面早期损坏的现象与试验分析

首先对纷杂的早期损坏现象进行了归纳分类，又通过对若干条高等级路面的实地调查发现了4种新的损坏现象．试验分析表明，大空隙率增大了沥青混凝土的透水性、降低了耐久性和抗拉强度，对沥青与集料的粘附性提出了更高的要求，而常用的沥青混合料空隙率设计处于这一不利的空隙率区间．大空隙率与荷载和水的综合作用是诱发早期损坏的主要原因．     

Photoluminescence properties of Ca_4La_6(SiO_4)_4(PO_4)_2O_2-based phosphors for wLEDs

The apatite compound Ca_4La_6(SiO_4)_4(PO_4)_2O_2(CLSPO) was explored as the host material for phosphors used in white light-emitting diodes(w LEDs). The crystal structure of the CLSPO host prepared by the solid-state reaction method was investigated with Rietveld refinement. The rare earth ions(Eu~(3+)/Tb~(3+)/Ce~(3+), Tb~(3+)/Tb~(3+), Mn~(2+))activated CLSPO phosphors were synthesized, and their photoluminescence properties, quantum yields, as well as thermal stabilities, were studied. Under near-ultraviolet excitations, the Eu~(3+) and Tb~(3+) -doped CLSPO compounds exhibited red and green emissions with high luminescence efficiencies. Besides, tunable emissions from green to orange were obtained by introducing Mn~(2+) ions into the Tb~(3+) -doped CLSPO samples. The results showed that the phosphors studied may have potential applications for w LEDs.     

Effect of 1070 nm laser intensity on parameters of In_(0.3)Ga_(0.7)As solar cell

The photoelectric properties of In_(0.3)Ga_(0.7) As solar cells applied in laser wireless power transmission(LWPT) were studied when they were irradiated by 1070 nm continuous wave(CW) laser of various intensities. The influences of laser intensity on solar cell parameters extracted by the pollination algorithm were analyzed quantitatively.Results show that the conversion efficiency of the cell rose to the maximum and then decreased rapidly in the laser intensity range of 50–900 mW/cm2. With higher energy laser irradiation, the rise of ideality factor and reverse saturation current would lead to the degradation of voltage at the maximum power point, which was the main reason for the decrease of conversion efficiency. The results provide the basis for choosing the appropriate input energy in the case of different transmission systems.     

激光导致水击穿和等离子体形成过程的物理分析

对短脉冲激光作用水介质中引起光学击穿的机制进行了分析,通过自由电子密度速率方程的数值解确定激光的击穿阈值.将数值计算结果与波长在可见光和近红外波段,脉宽为ns、ps和fs的激光脉冲在纯净水和含有杂质的水中的实验测量的击穿阈值作了比较.还计算了等离子体中自由电子密度的演化、等离子体吸收系数和能量密度.通过解自由电子密度速率方程得到结果与实验测量的值符合得很好.     

浅谈矿山生产中机电设备的安全管理

随着现代社会经济建设的不断进步,我国的矿山事业发展也相当迅速.矿山生产中机电设备的安全管理问题也越来越突出,“安全第一、预防为主、综合治理”的方针成为矿山安全工作的主旋律.分析了矿山安全生产的具体的现场情况,浅谈矿山生产中机电设备的安全管理及措施,利于维持山矿企业的持续稳定发展.     

基于RFID技术的混凝土搅拌厂车辆识别系统设计

以工控机(IPC)为平台,RFID技术为核心,综合应用数据库、PLC、有线视频传输等技术设计了一套集语音、视频、现场控制于一体的混凝土搅拌厂车辆识别系统。应用表明,该系统提高了混凝土搅拌厂的生产和管理效率。     

激光等离子体干涉条纹的图像处理方法研究

为了研究激光等离子体内部电子密度的分布,采用计算机图像处理方法对激光等离子体干涉条纹进行处理。利用Mach-Zehnder干涉仪采集激光等离子体干涉图。对得到的激光等离子体干涉条纹进行滤波和锐化预处理,然后利用二值化和细化等方法对降噪后的激光等离子体干涉图进行处理,得到等离子体干涉条纹的细化图。最后对细化后的干涉条纹偏移量进行Abel逆变换,得到激光等离子体电子密度径向分布。     

非均布轮载作用下沥青路面应力分析

轮胎对路面作用的荷载模式长期以来被简化为圆形均布的形式,与实际情况有很大区别,为此,采用三维20结点线弹性有限元方法得到了三种非均匀轮载作用下沥青路面内部的应力场,并分析了不同轮载模式下,在轮胎与路面接触区域附近,路面结构力学反应的不同规律,同时,根据超载轮胎接地压力的实际分布形式,分析了车辆超载绎路在的影响,并初步探讨了道路表面发生损坏的原因。     

Application of ultrasonic surface waves in the detection of microcracks using the scanning heating laser source technique

This letter reports the application of the scanning heating laser source technique to detect microcracks that may be undetected by conventional methods.In the proposed approach,we monitor changes in the transmitted surface acoustic waves(SAWs) as a heating source is scanned over the crack.The experimental system for microcrack detection by a scanning heating laser source is obtained by exploiting the strong dependence of the transmission efficiency of acoustic pulses on the state of the contacts,whether open or closed,between the crack faces.Microcracks can be detected successfully by confirming the heating position at the point of maximal improvement of the transmission efficiency of the SAWs.