摇摆桁架-钢框架结构的刚度比需求及地震响应分析

摇摆墙体系作为一种具有良好工程应用前景的新型结构形式被越来越多的工程人员所接受,但其自重大、易开裂、增大结构质量等问题一直困扰着广大科研人员。考虑到传统的摇摆墙体系的诸多不足,该文提出了摇摆桁架-钢框架体系,并对摇摆桁架的设计方法进行了探索与研究,给出了基于需求刚度比的设计建议。基于小、中、大震作用下的时程分析,对耗能构件的能量耗散以及累积位移延性进行了分析,研究了摇摆桁架-钢框架体系塑性铰形成过程以及结构的地震失效模式。结果表明,采用摇摆桁架-钢框架体系能显著改善、优化和控制钢框架结构的地震失效模式,提高结构的抗震性能。摇摆桁架体系作为-种新型摇摆结构,其功能可恢复性明显高于传统的抗震设计结构。     

设置BRB桥梁排架墩基于位移抗震设计方法

为发展具有损伤可控和自复位性能桥梁双柱墩,选取铅挤压阻尼器(lead-extrusion dampers, LEDs)为可更换耗能装置,并通过预应力筋提供自恢复力,组成摇摆-自复位(rocking self-centering, RSC)双柱墩体系(RSC-LEDs);通过对其抗震性能的研究,对应发展了一种基于等能量设计流程(equivalent energy-based design procedure, EEDP)的设计方法。首先建立了RSC-LEDs双柱墩的数值分析模型,结合一RSC双柱墩试件的拟静力结果验证了建模方法的正确性。在此基础上,定性分析了阻尼器出力、初始预张拉力、无粘结预应力筋配筋率、上部结构重量及盖梁-墩柱刚度比对RSC-LEDs双柱墩滞回性能的影响。设计了32组不同参数的RSC双柱墩试件开展回归分析,并结合RSC-LEDs双柱墩的力学特性,得到了RSC-LEDs双柱墩等效屈服强度、刚度的半经验计算公式。结合中国公路抗震设计规范和EEDP,提出一种适用于RSC-LEDs双柱墩体系的两阶段抗震设计方法,设计案例分析表明：半经验计算公式可较为准确地估算RSC-LEDs双柱墩的等效刚度及屈服强度;所提出的设计方法可使RSC-LEDs双柱墩达到预期的能力曲线,并实现在E1地震作用下保持弹性,在E2地震作用下LEDs屈服耗能且地震位移需求得到控制的设计目标。     

Chemical beam epitaxy and laser-modified chemical beam epitaxy of InGaAs using tris-dimethylaminoarsenic

The growth of In_xGaj_1−xAs (x = 0.13–0.25) on GaAs by chemical beam epitaxy (CBE) and laser-modified CBE using trimethylindium (TMIn), triethylgallium (TEGa), and tris-dimethylaminoarsenic (TDMAAs) has been studied. Reflection high-energy electron diffraction measurements were used to investigate the growth behavior of InGaAs at different conditions. X-ray rocking curve and lowtemperature photoluminescence (PL) measurements were used to characterize the InGaAs/GaAs pseudomorphic strained quantum well structures. Good InGaAs/GaAs interface and optical property were obtained by optimizing the growth condition. As determined by the x-ray simulation, laser irradiation during the InGaAs quantum well growth was found to enhance the InGaAs growth rate and reduce the indium composition in the substrate temperature range studied, 440–500°C, where good interfaces can be achieved. These changes, which are believed to be caused by laser-enhanced decomposition of TEGa and laser-enhanced desorption of TDMAAs, were found to depend on the laser power density as well. With laser irradiation, lateral variation of PL exciton peaks was observed, and the PL peaks became narrower.     

利用云南锰矿资源生产中碳锰铁的工业化实践

叙述了利用摇炉法应用云南锰矿生产中碳锰铁的工业化实践，它的成功有利于有效利用我省的高硅锰矿资源。     

A study of etch pit density and x-ray rocking curves for GaAs substrate evaluation

The relationship of structural defects to the electrical properties of semiconductor materials is discussed. Etch pit density (EPD) measurements are normally used to evaluate dislocation density. A nondestructive, quantitative method for evaluation of substrate defect populations is needed for quality assurance. In this study, double crystal x-ray diffraction rocking curves are investigated for this purpose. Rocking curve widths are determined experimentally for a set of GaAs substrated with a range of EPD. The experimentally determined values are also compared with those calculated from simulated rocking curves based on x-ray diffraction theory. Limited correlation between rocking curve widths and EPD is observed. Formerly of Spectrum Technology Inc., Holliston, MA     

摇头型超声电机在国内外的发展

文章从原理上对摇头型超声电机进行了阐述和分类，并介绍了摇头型超声电机在国内外的最新发展动态。     

Material quality characterization of CdZnTe substrates for HgCdTe epitaxy

Cd_1−xZn_xTe (CZT) substrates were studied to investigate their bulk and surface properties. Imperfections in CZT substrates affect the quality of Hg_1−xCd_xTe (MCT) epilayers deposited on them and play a role in limiting the performance of infrared (IR) focal plane arrays. CZT wafers were studied to investigate their bulk and surface properties. Transmission and surface x-ray diffraction techniques, utilizing both a conventional closed-tube x-ray source as well as a synchrotron radiation source, and IR transmission micro-spectroscopy, were used for bulk and surface investigation. Synchrotron radiation offers the capability to combine good spatial resolution and shorter exposure times than conventional x-ray sources, which allows for high-resolution mapping of relatively large areas in an acceptable amount of time. Information on the location of grain boundaries and precipitates was also obtained. The ultimate goal of this work is to understand the defects in CZT substrates and their effects on the performance and uniformity of MCT epilayers and then to apply this understanding to produce better infrared detectors.     

往复式轧钢机清洗机的研制

 愈来愈多的轧机使用厂家提出了对轧机专用清洗设备的需求，受一大型钢铁公司的委托，设计研制了轧机清洗机设备－－往复式轧机清洗机。介绍了往复式轧钢机清洗机的研制了开发意义和应用场合，轧钢机清洗机的总体布局和结构特点，及其工作原理和工作过程     

江西某钨钼铜矿石选矿试验研究

介绍了江西某钨钼铜矿矿石的选矿试验。试验通过对选别流程和粗选设备进行不同方案对比,选择了合适的方案,在小型试验基础上进行了扩大试验,为建厂投产提供了可靠依据。     

Numerical study on the cyclic response of AFRP reinforced columns with externally unbonded energy dissipaters

Fiber-reinforced polymer bars are gaining increased use in the construction market as a replacement to steel reinforcement for concrete structures. However their use as compression members is limited due to their mechanical properties, typically low flexural rigidity, so that local buckling may occur relatively at low stress levels. Their premature rupture in reinforced concrete (RC) columns could be eliminated by enhancing the columns’ response elastically and concentrating damage to the externally installed, replaceable post-tensioned structural fuses. This paper is part of a larger numerical and experimental investigation to develop and validate design methods for a rocking aramid fiber reinforced polymer (AFRP) reinforced concrete column. The numerical study, implemented using the Extreme Loading for Structures software, consists of a total of thirteen columns. The columns were subjected to axial load followed by cyclic lateral load up to failure to examine the effectiveness of the rocking connection and overall response. The effect of key variables such as longitudinal bar ratio, structural fuse sizes and tie spacing was investigated. Ductility and energy dissipation gains of the rocking AFRP RC columns were compared to that of the conventionally reinforced steel column, and expected performance of the rocking connection was achieved.