基于桥梁结构的动态称重系统算法研究

基于桥梁结构影响线加载的动态称重系统（B—WIM）便携且可循环使用,近几年在国外引起了学者深刻关注,并开发了相应的商业设备,而我国对此进行相关研究见于文献的很少。该系统可为中小跨径桥梁开展汽车荷载调查提供新的思路,并为中小跨径桥梁汽车活载评估提供直接参数。详细介绍了该系统算法原理,以三轴汽车荷载作为示例介绍了影响线坐标值标定过程,并给出了汽车荷载计算的通用矩阵表达式,为下一步进行设备开发的软件程序提供了理论支持。     

Timed quenching process for large-scale AISI 4140 steel shaft

The mechanical properties of AISI 4140 steel shaft with a diameter larger than 200 mm are difficult to meet the requirements and cracking occurs easily in water quenching, due to insufficient cooling ability of oil quenching. A new technology, named alternately timed quenching (ATQ), using water and air in turn as quenching media instead of oil or polymer aqueous solution, is applied to quench the large-scale AISI 4140 steel shaft. Two ATQ processes are determined with the aid of computer simulation first and the corresponding experiments are carried out consequently. The results show that the proposed technology can significantly reduce the surface cracking tendency and improve the mechanical properties in practical production of such large-scale shaft forgings.     

Aero-optical characteristics of supersonic flow over blunt wedge with cavity window

The optical rays that form the image of an object and propagate a supersonic flow over a vehicle are refracted by the density variations. A numerical analysis of the aero-optical characteristics of supersonic flow over blunt wedge with a cavity window is carried out. A hybrid method of Reynold averaged Navier-Stokes and direct simulation Monte Carlo (RANS/DSMC) is employed to simulate the flowfield. Refraction factor is introduced to evaluate the flowfield’s aero-optical characteristic. The results show that mean flow’s aero-optical effects are mainly caused by the shock wave, the expansion wave and the turbulent boundary layer. Fluctuation flow’s aero-optical effects are mainly caused by the turbulent boundary layer and the shock wave induced by the cavity window. The aero-optical effects at the leading side of window are caused by the mean density variations, while the effects at the trailing side are caused by the density fluctuations. Different draft angles of the cavity window are investigated. The airborne optical devices of supersonic vehicle should be mounted in the middle of the cavity window with a large draft angle.     

基于物联网的道路交通管理系统分析

将道路交通中基础设施和相关要素通过EPC技术进行多样标签的编组,并运用物联网的核心技术之一的RFID进行识别,形成感应层。通过运用多种通信技术进行信息传输,构建基于物联网的道路交通体系构架和管理系统,并对道路交通的数据和信息进行分析、判断、处理,使道路交通体系构架内各层面相互协调、沟通,进行数据信息的传输与反馈。     

隧道地震动力模型试验相似准则和参数设计

隧道地震动力模型试验是在实验室中研究隧道结构地震响应和破坏机理的重要方法。其中,模型相似准则和相似参数的确定是正确进行模型试验的关键环节。以相似理论为依据,推导出隧道地震动力模型试验的相似准则,首先确定模型的几何相似比和弹模相似比,即可根据相似准则确定其余各相似参数。     

低温下沥青中柔性短纤维桥联应力计算模型

分析了柔性纤维增强脆性材料特点,建立了单根纤维从沥青中拔出时的受力模型。采用球面坐标系建立空间均匀分布短纤维桥联应力的计算模型,计算了沥青断裂时短纤维产生的桥联应力。采用大尺寸的纤维沥青试件进行低温拉伸断裂试验,实测短纤维的桥联应力。通过对桥联应力的计算值和实测值进行试算拟合,修正了计算模型中的参数。分析结果表明：桥联...     

超高性能钢纤维混凝土力学性能

用端部弯折型、端部扁平型和波浪型3种钢纤维分别配制抗压强度大于100 MPa的超高性能纤维混凝土,纤维体积掺率分别为1.0%、2.0%、2.5%和3.0%.通过立方体抗压试验和梁抗弯试验,研究钢纤维形状和体积掺率对超高性能纤维混凝土流动性、抗压强度、抗弯强度、断裂能和弯曲韧度的影响.试验结果表明:纤维体积掺率为1.0%...     

三叶因子3在胃溃疡大鼠脾脏不同部位的表达

目的研究三叶因子3(TFF3)在胃溃疡大鼠脾脏不同部位的表达。方法胃前壁黏膜下注射冰乙酸制备大鼠胃溃疡模型,免疫组织化学法分别检测正常组(6只)和溃疡组(42只)雄性大鼠脾脏TFF3的表达。结果①溃疡组大鼠脾脏明显肿大、充血;与正常组相比白髓面积明显增大(P<0.05或P<0.01),至6 d组最大,边缘区增厚(P<0.05或P<0.01),至10 d组最厚;红髓面积减少。②TFF3阳性反应物呈棕黄色颗粒状分布于胞质中。③TFF3在正常组大鼠脾脏中呈弱阳性表达,在溃疡组表达明显增高(P<0.05或P<0.01)。溃疡组白髓中阳性细胞TFF3平均吸光度值各组与正常组相比明显增高(P<0.05),以10 d组增高最为明显;边缘区阳性细胞TFF3吸光度值1、2 d和6 d组与正常组相比明显增高(P<0.05或P<0.01),以6 d组增高最为明显;红髓阳性细胞TFF3吸光度值1、2、6 d和14 d组与正常组相比明显增高(P<0.05或P<0.01),以6 d组增高最为明显。④溃疡组边缘区TFF3表达与损伤时间呈负相关(P<0.05)。结论 TFF3在胃溃疡大鼠脾脏各部位呈高水平表达,可能通过提高脾脏免疫反应性促进胃溃疡的愈合。     

猪源性CTLA4Ig基因重组腺病毒载体的构建及鉴定

目的 为进行基因转移阻断T细胞共刺激通路诱导异种胰岛细胞移植免疫耐受的研究,构建携带猪源性CTLA4Ig融合基因的重组腺病毒载体.方法 分离猪外周血单个核细胞,经RT-PCR扩增pCTLA4胞外段基因.将PCR产物克隆入pGH IgG,阳性克隆以双酶切及测序鉴定.将目的融合基因pCTLA4Ig克隆人腺病毒穿梭载体pSh...