单光纤光栅对温度与应变的同步测量

提出了一种采用单光纤布拉格光栅(FBG)进行温度与应变同步测量的新颖设计。一根FBG被分成等长的两部分,用环氧胶水涂敷在其中一部分的表面,再套上金属套管,此时可以看成具有不同的布拉格波长的2个FBG,利用它们之间不同的杨氏模量和热膨胀系数,应变和温度能够同步测量。实验结果表明,在2700με和75℃的测量范围内,可以达到约6.1με和1.0℃的应变和温度精确度,误差主要来源于光谱仪分辨率的限制和FBG其中一部分的胶水涂抹不够均匀,通过使用高分辨率的解调仪和提高胶水涂抹工艺可得到更高的测量精确度。     

基于硼酸溶液处理的GaAs/InP低温晶片键合技术

提出了一种基于硼酸溶液的GaAs/InP低温晶片键合技术,实现了GaAs/InP基材料间简单、无毒性的高质量、低温(290℃)晶片键合。GaAs/InP键合晶片解理截面的扫描电子显微镜(SEM)图显示,键合界面整齐,没有裂缝和气泡。通过键合过程,InP上的In0.53Ga0.47As/InP多量子阱结构转移到了GaAs基底上。X射线衍射及荧光谱显示,键合后的多量子阱晶体质量未变。二次离子质谱(SIMS)和Raman光谱图显示,GaAs/InP键合晶片的中间层厚度约为17 nm,界面处B元素有较高的浓度,键合晶片的中间层很薄,因此可以得到较好的电学、光学特性。     

改善钢桥面铺装层高温作用的有效措施

为了降低钢桥面铺装层内较高的温度,提高铺装材料使用性能,推迟桥面的早期破坏.采用有限元手段,以傅里叶传热定律为理论基础,根据气象部门提供的气象资料,对开放式钢箱梁及封闭式钢箱梁铺装层的温度场进行研究.结果表明:开放式箱梁可以降低桥面铺装层温度,降低高温持续作用时间,改变桥面铺装层高温的作用位置.     

Effect of barium oxide on the formation and coexistence of tricalcium silicate and calcium sulphoaluminate

Formation and coexistence of tricalcium silicate (C₃S) and calcium sulphoaluminate (C₄A₃ ) minerals in Portland cement clinker containing calcium sulphoaluminate were investigated. The f-CaO content, mineral composite and formation of mineral in the clinker were analyzed respectively by chemical analysis, differential scanning calorimetry(DSC) and X-ray diffraction. The results show that, adding a suitable amount of BaO can improve the burnability of raw meal and promote the f-CaO absorption. Tricalcium silicate and calcium sulphoaluminate minerals can form and coexist in clinkers at 1 234–1 317 °C by the addition of BaO to the raw meal. A suitable amount of BaO expanded the coexistence temperature of two minerals by 58 °. Funded by the National Basic Research Program of China (No. 2009CB623100), National Eleven Five-Year Scientific and Technical Support Plans (No. 2006BAF02A24), the Natural Science Fund for Colleges and Universities in Jiangsu Province(No. 08KJB430006), the Open Fund for the Key Laboratory of Inorganical and Composite Materials in Jiangsu Province(No. wjjqfhxc1200801) and the Innovation Fund of Doctoral Dissertation of Nanjing University of Technology (No. BSCX200705)     

H型截面单层单跨钢框架火灾行为试验

对2榀H型截面单层单跨钢框架进行了火灾行为的足尺试验研究.全部试验采用自行研制的火灾试验炉,试验结果表明炉子性能稳定,使用方便.试验中考虑了不同受火工况对钢框架火灾行为的影响.通过试验得出了钢框架温度场分布和变形的变化规律.试验结果表明:火灾下,梁柱全部受火的单层单跨钢框架(节点受到保护)破坏方式为钢柱压屈破坏,破坏位置在受到保护的钢节点下部的钢柱上.试验研究为今后钢结构火灾行为的研究提供依据.     

大口径光学透镜瞬态温度场模拟

为考察热辐射效应对光学元件稳、瞬态温度场的影响,给出了考虑辐射和导热耦合换热情况下复杂几何结构光学透镜稳、瞬态热特性的适体坐标下离散坐标法.对喷管形和圆柱形介质进行计算并与其他方法比较表明,建立的适体坐标系下辐射与导热耦合换热计算方法精度较好.对两端为球缺中间为圆柱的大口径透镜内的辐射与导热耦合换热过程进行了数值模拟.计算结果表明,为了精确地预测半透明介质如透镜内的温度分布,应该考虑辐射与导热耦合作用,且应当考虑介质的光谱特性.     

小型加热炉炉温微机控制系统

针对小型试验反应器的特点,介绍了PID自整定、串级控制、采样调节、程序适应控制、程序升降温等多种控制策略在该种反应器温度控制上的应用。结果表明,反应器内温稳态温度控制精度高,升降温曲线能很好地跟踪开停工工艺条件,开停工简单方便,参数整定方便,适应性强,控制方式灵活,减轻了操作人员的劳动强度,提高了试验装置的自动化水平。     

Oxidation behavior of in-situ Al2O3/TiAl composites at 900℃ in static air

In-situ Al2O3/TiAl composites were successfully synthesized from the starting powders of Ti, Al, TiO2 and Nb2O5. The oxidation behavior of the composites at 900℃ in static air was investigated. The results indicate that the composite samples present a much lower oxidation mass gain. Under long-time intensive oxidation exposure, the formed oxide scale is multi-layer. The formation of the outer TiO2 layer is fine and dense, the internal Al2O3 scale has good adhesiveness with the outer TiO2 scale, and the TiO2+Al2O3 mixed layer forming the protective oxide scale is favorable for the improvement of oxidation resistance. It is believed that the incorporation of Al2O3 particulates into the metal matrix decreases the coefficient of thermal expansion of the substrate, and forms a local three-dimensional network structure that can hold the oxide scale. The formation of the oxide scale with fmer particle size, stronger adherence, less micro-defects and slower growth rate can contribute to the improvement of oxidation resistance. Nb element plays an important role in reducing the internal oxidation action of the materials, restraining the growth of TiO2 crystals andpromoting thc stable formation of the Al 2O3-riched layer,which is benfeicial to improve the oxidation properties.     

Effects of annealing temperature on the microstructure and properties of the 25Mn-3Si-3Al TWIP steel

Microstructures and mechanical properties of the 25Mn twinning induced plasticity (TWIP) steel at different annealing temperatures were investigated. The results indicated that when the annealing temperature was 1000°C,the 25Mn steel showed ex-cellent comprehensive mechanical properties,the tensile strength was about 640 MPa,the yield strength was higher than 255 MPa,and the elongation was above 82%. The microstructure was analyzed by optical microscopy (OM),X-ray diffraction (XRD),and transmission electron...     

F68大单体/HEMA共聚水凝胶的制备及性能研究(Ⅰ):温度敏感性

本文以温度敏感性Pluronic F68与甲基丙烯酸缩水甘油酯(GMA)反应制备可光聚合的F68/GMA大分子单体,再在水溶液中与丙烯酸(AA)单体和甲基丙烯酸β-羟乙酯(HEMA)经紫外光原位聚合制备温度敏感水凝胶。详细地研究了水凝胶在不同温度下的溶胀性能。溶胀动力学测量的结果表明,该水凝胶具有温度响应性且具有可逆性。