Using the built environment to oversample walk,transit, and bicycle travel

Characteristics of the built environment (BE) have been associated with walk, transit, and bicycle travel. These BE characteristics can be used by transportation researchers to oversample households from areas where walk, transit, or bicycle travel is more likely, resulting in more observations of these uncommon travel behaviors. Little guidance, however, is available on the effectiveness of such built environment oversampling strategies. This article presents measures that can be used to assess the effectiveness of BE oversampling strategies and inform future efforts to oversample households with uncommon travel behaviors. The measures are sensitivity and specificity, positive likelihood ratio (LR+), and positive predictive value (PPV). To illustrate these measures, they were calculated for 10 BE-defined oversampling strata applied post-hoc to a Seattle area household travel survey. Strata with an average block size of <10 acres within a ¼ mile of household residences held the single greatest potential for oversampling households that walk, use transit, and/or bicycle.     

Field tests of a dynamic green driving strategy based on inter-vehicle communication

This paper presents the design and results for field tests regarding the environmental benefits in stop-and-go traffic of an algorithmic green driving strategy based on inter-vehicle communication (IVC), which was proposed in Yang and Jin (2014). The green driving strategy dynamically calculates advisory speed limits for vehicles equipped with IVC devices so as to smooth their speed profiles and reduce their emissions and fuel consumption. For the field tests, we develop a smartphone-based IVC system, in which vehicles’ speeds and locations are collected by GPS and accelerometer sensors embedded in smartphones, and communications among vehicles are enabled by specially designed smartphone applications, a central server, and 4G cellular networks. Six field tests are carried out on an uninterrupted ring road under slow or fast stop-and-go traffic conditions. We compare the performances of three alternatives: no green driving, heuristic green driving, and the IVC-based algorithmic green driving. Results show that heuristic green driving has better smoothing and environmental effects than no green driving, but the IVC-based algorithmic green driving outperforms both. In the future, we are interested in field tests under more realistic traffic conditions.     

相似理论在分节驳结构模型试验中的应用

本文讨论了相似理论在分节驳模型试验中的应用。依据相似理论的基本原理,详细讨论了由模型试验结果去预报实船结构应力的可行性,提出了模型产生畸变的情况下,模型畸变的修正方法——有限元预测系数法。通过计算给出了进行模型畸变修正的δ_p-C_t曲线。     

人心窦房结的光镜观察

本文对11例人心窦房结的形态和位置作了连续切片观察。窦房结位于界嵴上部的心外膜深面约1mm 左右,结的长轴与界嵴长轴一致,其形状多种多样。成人结的大小为14×3.6×1.09mm~3;儿童结的大小为6.9×2.3×0.8mm~3.窦房结组织染色淡(HE 染色),组织致密,结中心有较大动脉穿过。结细胞明显较一般心房肌细胞小,其中P 细胞类似原始心肌细胞,核大、胞质肌原纤维少,染色淡.T 细胞为短柱状,核较小染色深浅介于P 细胞和心房肌细胞之间状态.上述两种细胞位于胶原纤维相互交织的网眼内。     

张力式平台运动响应的理论计算与模型试验

本文对一座51700t作业水深为256m的张力式平台模型在规则波及不规则波中进行了试验,并利用二维及三维计算程序计算了该平台的波频运动响应,计算与实验结果颇为一致。文中还讨论了运动响应的非线性问题,最后对在生存海况下估算张力式平台纵荡及横荡的方法提出了看法。     

智能水箱风扇电动机控制系统

介绍商用车水箱风扇电动机控制系统的一种优化方式,精确控制水箱风扇电动机工作的温度范围,从而提升整车性能。     

婴幼儿肺炎肺动脉高压期和心衰期的判断

本文采用肺阻抗微分图时相分析法测量RPEP/RVET和RPEP/T两个比值以区别婴幼儿肺炎肺动脉高压期和心衰期。然后再以此两个比值作为客观指标观察心衰期及肺动脉高压期的临床表现,提出临床上的判断标准及何时需用血管扩张药。     

武汉长江斜拉桥主梁分段施工混凝土接缝性能试验

根据武汉长江公路斜拉桥主梁设计的需要，进行了５片具有分段灌筑接缝的ＰＰＣ形模型梁的试验。结果表明，接缝处混凝土抗拉强度明显降低，其强度降低系数初步建议取０．５；试验表明，接缝对梁的极限抗弯强度的没有影响。     

风湿性心脏病心肌细胞线粒体膜磷脂损伤与换瓣术后低心排血量的关系

目的　探讨风湿性心脏病心肌细胞线粒体膜磷脂损伤与换瓣术后低心排血量的关系。方法　将 2 0例风湿性二尖瓣替换患者按术后有无严重低心排血量分为正常心排血量组 (n =1 4)和低心排血量组 (n =6) ,另 8例健康意外脑死亡者心肌为正常对照组。应用电镜细胞化学法测定术前右房心肌细胞线粒体膜磷脂超微结构定位改变 ,同时测定术中再灌注 3～ 5min时全心肌氧摄取率 ,并定量分析上述指标变化与术后低心排血量的关系。结果　风湿性心脏病心肌细胞线粒体膜磷脂结构定位呈现不同程度的脱失改变。其中低心排血量组与正常心排血量组比较 ,心肌细胞线粒体膜磷脂结构小部分脱失 (7 5%± 2 6%vs 4 9%± 1 6% )和大部分脱失(4 5%± 2 0 %vs 2 6%± 1 7% )比率均明显增高 ,且再灌注 3～ 5min时全心肌氧摄取率 [(2 .30± 0 50 )Vol%vs(3.42± 0 .60 )Vol% ]明显降低 (P均 <0 0 5)。结论　风湿性心脏病心肌细胞线粒体膜磷脂结构定位脱失程度与换瓣术后低心排血量的发生密切相关 ,可能是参与术后低心排血量形成、发展的细胞基础之一。     

上合示范区交大大道隧道总体方案设计

交大大道位于上合示范区南北纵向发展轴线,南接西海岸新区昆仑山路,北接营旧公路,可联系黄岛、上合示范区、少海、临空经济区等组团,既是区域内部重要生活服务性城市主干道,又承担着南北向过境交通,交通功能十分重要。从项目背景、功能定位、建设规模、主要技术标准和总体设计等方面对交大大道方案进行介绍,内容可供相关工程参考。