石家庄地铁1号线北宋站钢支撑轴力变化规律分析

基坑的整体稳定性及基坑周边地下管线、周边建筑物的稳定非常重要。介绍石家庄地铁1号线北宋站钢支撑施工中出现轴力频率读数仪数值变化的情况,从外部环境、基坑开挖支护以及主体工程的施工等方面分析数值波动原因。主要结论如下： 1）温度越高,钢支撑所受的轴力越大;温度越低,钢支撑所受的轴力越小。2）临近钢支撑施加轴力会减小已施加轴力的钢支撑所受轴力。3）未施工完成结构主体,只要强度达到设计混凝土强度要求,可以替代钢支撑,作为基坑支护的一部分。     

多年冻土路基融沉数值模拟

为考察多年冻土路基在温度变化下的融沉问题,建立了相应的有限元模型。通过选取典型断面,在青藏公路实测数据的基础上进行了路基温度场计算模拟,其结果为后续的路基融沉提供了温度场-力学耦合计算的前提。路基融沉计算模型在导入温度场后,分别进行了自重作用和温度作用下的融深对地基沉降变形影响的计算。结果表明,不同的冻土融深对沉降变形影响不同。多年冻土地区修建公路,应采取措施保护冻土上限,减小路基融化深度。最后,在融沉计算的基础上提取了相应的融沉曲线回归式。     

宁波地区下垫面日极值温度预测

根据宁波地区气象要素和草皮、砖块、沥青混凝土层、水泥混凝土层4种不同下垫面的表面温度资料,运用逐步回归统计分析方法,分析了4种下垫面表面极值温度与气象要素之间的关系,建立了各下垫面表面日最高和日最低温度的预测模型,并通过实测数据对预测模型进行了检验。结果表明:4种下垫面表面的日最高温度可表示为日最高气温、日太阳总辐射和风速的线性回归式;4种下垫面表面的日最低温度与日最低气温线性相关。模型预测值能较好地吻合实测温度。该模型可用于预测宁波地区草皮、砖块、沥青混凝土层、水泥混凝土层4种不同下垫面的极值温度,对水泥或沥青混凝土路表极值温度预测具有参考价值。     

涡轮增压器轴承体传热计算方法研究

通过对涡轮增压器传热机理的研究,利用专业传热分析软件ESC建立了轴承体传热仿真分析的有限元计算模型,对轴承体分别进行了稳态、瞬态的温度场计算,找到了仿真计算中需要优化的输入参数。为验证该轴承体传热仿真计算方法的合理性及计算结果的准确性,对同型号的涡轮增压器进行了试验验证,结果表明,该仿真计算方法合理,计算结果可信。     

桥梁基础温度裂缝产生的原因及预防措施

大体积混凝土桥梁基础的裂缝主要是有温度变化引起的。由于混凝土是热的不良导体,散热很慢,混凝土浇筑后,由于大量水泥发生水化反应,产生大量水化热,混凝土内部温度远较外部高,形成较高的温差,造成内部膨胀而外部收缩,使表面产生较大的拉应力,最终导致混凝土开裂。     

Comparative study on ghrelin level change and its related factors in hypertensive elders with psychological distress

Objective To investigate the change of plasma ghrelin level and explore the related factors of ghrelin alteration in elderly hypertensive patients with psychological distress. Methods A total of 300 elders, who were screened with Hamilton Anxiety Scale (HAMA), Hamilton Rating Scale for Depression (HAMD), and the Symptom Checklist-90 (SCL-90) for psychological stress and somato-psychological manifestations respectively, were divided into hypertension group (n=148) and non-hypertension group (n=152). Their blood samples were collected to measure the plasma level of ghrelin and total cortisol on the same day. Results The incidences of anxiety and depression were 27.7% and 11.7%, respectively, in all the enrolled elders. However, the rates of psychological distress, particularly anxiety, were significantly higher in the hypertensive elders than in the non-hypertensive ones (43.2% vs. 12.5%). Anxiety was positively related to the cortisol level but negatively related to the plasma ghrelin level, and the latter two were negatively correlated with each other. Conclusion Chronic increase of plasma cortisol induced by long-term anxiety can lead to the reduction of ghrelin level, which then adversely affects blood pressure in elders with psychological distress. Therefore, ghrelin might be a selective antihypertensive medicine for hypertensive elders with anxiety.     

Inhibitory action of docetaxel on the proliferation of HeLa and SiHa cells

Objective To study the inhibitory action of docetaxel (DOC) on the proliferation of HeLa and SiHa cells. Methods Cell morphological changes were observed with inverted phase contrast microscope. MTT was adopted to test and calculate the cell inhibition ratio. Flow cytometry was used to detect cell cycle. Results DOC had an obvious concentration-dependent inhibitory effect on the proliferation of both HeLa and SiHa cells. The inhibition ratio of DOC on SiHa was significantly higher than that on HeLa (P<0.05). DOC blocked HeLa at G2/M phase. Under the effect of DOC, the cell cycle of SiHa was not changed much. Conclusion DOC has an obvious inhibitory action on both HeLa and SiHa cells, which shows a promising prospect of DOC in clinical treatment of cervical cancer.     

交通与全球环境变化

在美国,交通部门、交通出行所带来的二氧化碳排放,占全部经济部门、经济活动所排放空气污染的1／4。交通与二氧化碳排放、二氧化碳排放与全球环境变化,全球环境变化对交通的影响、交通对全球环境的影响等等是一系列密不可分的问题。最新一期的美国交通研究会TRNews杂志,对上述问题中的交通与全球环境变化进行了高屋建瓴的讨论,有兴趣的读者,可以在以下网址免费阅读：     

季冻土地区沥青混凝土路面温度场分析

路面结构温度变化状况反映了外界环境因素对路面结构的作用,产生的温度应力是路面破坏的主要因素之一。从季冻土地区气候特点及其对路面结构的影响出发,对半刚性基层沥青路面温度场开展研究。     

重交通沥青路面车辙调查与试验分析

高速公路沥青路面车辙是路面的主要病害之一。通过对实例重交通沥青路面车辙的调查与室内外试验分析,研究了车辙发生后路面厚度、空隙率、油石比以及集料级配的变化规律,并通过路面温度场的变化进一步研究分析车辙发生的规律及其深层影响因素,为今后路面的施工质量控制以及对车辙的防控提供实测数据参考。