黄土隧道结构的振动台模型试验研究

为了研究黄土隧道结构在不同地震波及降雨条件下的地震响应和橡胶减震层的减震效果，按相似理论分别设计制作了缩尺比为1∶40的减震黄土隧道及非减震黄土隧道，在总降雨量50 mm，降雨强度10 mm·h^-1的条件下，分别加载近、远场地震波El-Centro波和Taft波，对比了地震波不同加速度条件下黄土隧道各测点的地震响应情况及土压力变化情况，通过减震模型和非减震模型各测点的应变变化情况分析了黄土隧道的减震效率。结果表明：在调幅和持时一致的情况下，黄土隧道结构对于不同的地震动具有明显的选择性，El-Centro地震动条件下的动力响应大于Taft地震动条件下的动力响应，说明黄土隧道结构的动力响应不仅取决于地震动的强度及持时，也与地震波的频谱特性有关，黄土隧道结构对近场地震波的响应大于远场地震波；对模型横向加载，模型各点的横向加速度和竖向加速度均有变化，横向的加速度响应大于竖向的加速度响应；拱顶位置的土压力较大，拱脚位置虽然土压力较小，但应变变化较大，应力集中现象明显；通过设置减震层可使衬砌不同部位的应变值均有所减小，且应变越大的部位减震率越高，不同工况下拱顶及拱脚的应变减震率接近50%，设置减震层不但可以减小衬砌结构的变形，而且能吸收地震能量，发挥围岩结构和衬砌结构的协同作用，减小土体的裂缝宽度及深度。     

地铁再生制动能量吸收装置

以往采用车辆吸收电阻吸收地铁列车运行过程中的再生能量,这就带来隧道和站内的温升问题,同时导致车体重量增加,造成大量的能源浪费并使地铁的建设费用和运行费用增加.为解决这一系列问题,有必要对再生能量吸收的相关技术进行系统研究.首先分析了电阻耗能型吸收装置的工作原理及功能,在此基础上设计了主电路,然后详细讨论了装置的控制策略,最后利用PSIM对系统进行了仿真,验证了系统方案的可行性.     

嵌入拉格朗日元法估算某些水下装置吸收波浪能研究(英文)

A simple approach is described to estimate the wave power absorption potential of submerged devices known to cause wave focusing and flow enhancement.In particular,the presence of a flow-through power take-off(PTO)system,such as low-head turbines,can be accounted for.The wave radiation characteristics of an appropriately selected Lagrangian element(LE)in the fluid domain are first determined.In the limit of a vanishing mass,the LE reduces to a patch of distributed normal dipoles.The hydrodynamic coefficients of this virtual object are then input in a standard equation of motion where the effect of the PTO can be represented,for example,as a dashpot damping term.The process is illustrated for a class of devices recently proposed by Carter and Ertekin(2011),although in a simplified form.Favorable wave power absorption is shown for large ratios of the LE wave radiation coefficient over the LE added mass coefficient.Under optimal conditions,the relative flow reduction from the PTO theoretically lies between 0.50 and 1 2≈0.71,with lower values corresponding to better configurations.Wave power capture widths,the sensitivity of results to PTO damping and sample spectral calculations at a typical site in Hawaiian waters are proposed to further illustrate the versatility of the method.     

船舶燃油计算机管理系统的研究

介绍了一种船舶燃油计算机管理系统的有关情况。该系统可以利用现在船上使用的检测报警系统计算机实现船舶燃油管理系统的计算机连续在线自动测量，实现船舶燃油管理中的统计、记录、运算和预测功能。     

SAMPAVE应力吸收层沥青结合料存储性能研究

通过对国产基质沥青进行类型和标号的试验选择,采用多种改性剂对基质沥青进行复合改性,并对改性剂的投料顺序、改性沥青的存储性能进行试验分析,研制出SAMPAVE应力吸收层沥青结合料,提出其生产工艺参数。综合性能指标结果表明：SAMPAVE应力吸收层沥青结合料性能分级达到PG76-28标准,完全满足应力吸收层混合料对结合料的要求。     

On the dependence of acoustic performance on pavement characteristics

Acoustic-based mix design is still far from achieving a clear and accepted rationale. The three main dominions (generation, absorption, propagation) which affect pavement acoustic performance involve a number of acoustic parameters. Their relationship with pavement properties is scarcely or insufficiently known. In more detail, the parameters that define the acoustic coupling between the two phases that comprise a porous material are: porosity, resistivity, tortuosity, and viscous and thermal factors. Consequently, the spectrum of a pavement absorption coefficient depends, in particular, on tortuosity, whose relationship with HMA (hot mix asphalt) bulk properties is still an issue.Given that, the study described in this paper aimed at: (i) assessing the effect of the tortuosity on the absorption coefficient of a pavement layer; (ii) assessing the dependence of tortuosity on mix design parameters and/or mix properties; (iii) deriving a straightforward algorithm to estimate the effect of tortuosity-related properties on the absorption coefficient.Based on the above issues, an experimental plan was designed and carried out in order to study these relationships and set out a tentative theoretical and practical framework. The relationships between acoustic and traditional bulk properties of pavement mixtures were analysed. Acoustic models and hydraulic analogies were considered and, based on them, relationships were formalised and submitted to experimental validations. A simple relationship to derive tortuosity from nominal maximum aggregate size and thickness was derived. This relationship was used to derive the frequency of the first peak of the absorption spectrum, based on HMA properties. Nominal maximum aggregate size and lift thickness emerged as key factors in patterning peak frequency.Future research will address a number of issues among which the following can be listed: synergetic assessment of the influence of HMA properties on the absorption coefficient over the entire spectrum, synergetic consideration of generation and absorption factors. Practical benefits and outcomes are expected for both practitioners and researchers.     

陶质焊接衬垫吸湿性研究

分析陶质焊接衬垫块的烧结和吸湿过程,介绍衬垫块吸水率和吸潮率试验方法.通过对不同致密度的衬垫块进行吸水率和吸潮率对比试验,发现衬垫块的吸湿主要是靠衬垫块内的多连通开口气孔,吸水率4％以下的衬垫块具有很少的多连通开口气孔,抗湿性好;随着衬垫块吸水率的增加,多连通开口气孔增多,衬垫块抗湿性变差.     

电流型Z源逆变器的SHE-PWM控制

传统的电流源应用中,需要保证电路不能出现阻断状况。使用z源的电流源不仅允许电路出现阻断状况,而且通过对电路的控制实现电流的升降。本文对电流源的z源拓扑结构进行了分析,并推导了其输入输出的关系式。同时将这种拓扑结构运用在了基于SHE-PWM控制的单相电流源逆变器上。以及运用MATLAB／SIMULINK工具对分析进行了仿真验证,以此说明这个电路的特性。     

不同给药途径的特异性免疫治疗的疗效及安全性

目的比较两种不同给药方式进行尘螨变应原特异性免疫治疗对缓解期哮喘患者的临床疗效和安全性。方法筛选40例缓解期尘螨过敏的哮喘患者,随机分为两组,分别给予尘螨变应原舌下含服(SLIT)和皮下注射(SCIT)脱敏治疗,总疗程为1年,观察两组的临床疗效和安全性。结果两组患者治疗前后吸入糖皮质激素日剂量、哮喘控制问卷(ACQ)、哮喘生命质量调查问卷(AQLQ)评分、尘螨皮肤试验反应度均得到改善(P<0.05),但改善程度组间比较无显著性差异(P>0.05)。两组患者哮喘得以控制的比例在治疗前后均有所增加(P<0.05),但组间无统计学差异(P>0.05)。肺功能指标、血清sIgE、嗜酸粒细胞百分比在治疗前后无明显变化(P>0.05)。SLIT组常见不良反应为局部刺激、胃肠道不适,SCIT组常见不良反应为皮疹、乏力和哮喘发作。结论尘螨变应原SLIT与SCIT特异性免疫治疗疗效相当,前者在依从性及安全性上具有更大优势。     

SAMPAVE应力吸收层沥青结合料存储性能研究

通过对国产基质沥青进行类型和标号的试验选择,采用多种改性剂对基质沥青进行复合改性,并对改性剂的投料顺序、改性沥青的存储性能进行试验分析,研制出SAMPAVE应力吸收层沥青结合料,提出其生产工艺参数。综合性能指标结果表明:SAMPAVE应力吸收层沥青结合料性能分级达到PG76-28标准,完全满足应力吸收层混合料对结合料的要求。