泥岩边坡防护设计探讨

泥岩属于典型沉积岩类的原生软岩,种类繁多,分布较为广泛,是工程性质较差的一类岩石,给工程实践带来了很大困扰。文中探讨了泥岩边坡岩土力学指标的确定方法,采用FLAC数值模拟对该方法进行了验证。同时综合考虑多方面因素将泥岩边坡稳定性分为:稳定、基本稳定、稳定性差、不稳定4类。根据边坡的防护设计原则,结合各类边坡的特征,提出了一些防护措施。     

液压转辙机挤脱力测试仪的设计

为检测液压转辙机挤脱力的大小及变化情况,设计了一款液压转辙机挤脱力测试仪.利用ARM7微控制器LPC2214芯片和μC/OS-Ⅱ实时操作系统,构建了测试仪的硬件平台和软件平台.该测试仪通过LCD以数字和曲线的形式实时显示挤脱力的变化情况,可存储测试数据,并且通过RS232或USB接口上传到PC进行数据分析和曲线及分析结果的打印.实际应用表明,此测试仪完全满足设计要求,且具有稳定性好、精度高、抗干扰性强的优点.     

不同厚度下船舶板材高频感应自由弯曲成形

应用ANSYS软件建立高频感应自由弯曲有限元模型,研究了船板高频感应成形板厚对可加热温度、变形角度、应力、变形及冷却后的残余应力的影响。结果表明:不同厚度的船舶板材可加热温度皆在860℃以上进入奥氏体温度区。在无约束、忽略船板自重的情况下,不同厚度的船舶板材单面弯曲角度在10-2数量级;加热结束后,不同厚度的船舶板材的应力都达到屈服应力,发生了塑性变形。冷却结束后残余应力主要集中在线圈正下方。随着板厚的增加,可加热温度下降,并在中厚板区有波动;弯曲角度先增加,后减小;最大残余应力先减小,后增加。在给定加热频率和功率条件下,船板的高频感应加热变形的最有效厚度为14 mm。     

Web-based biomedical literature mining

With an upsurge in biomedical literature, using data-mining method to search new knowledge from literature has drawing more attention of scholars. In this study, taking the mining of non-coding gene literature from the network database of PubMed as an example, we first preprocessed the abstract data, next applied the term occurrence frequency (TF) and inverse document frequency (IDF) (TF-IDF) method to select features, and then established a biomedical literature data-mining model based on Bayesian algorithm. Finally, we assessed the model through area under the receiver operating characteristic curve (AUC), accuracy, specificity, sensitivity, precision rate and recall rate. When 1 000 features are selected, AUC, specificity, sensitivity, accuracy rate, precision rate and recall rate are 0.868 3, 84.63%, 89.02%, 86.83%, 89.02% and 98.14%, respectively. These results indicate that our method can identify the targeted literature related to a particular topic effectively.     

用于车辆自主导航的多传感器数据融合方法

提出了一种用于车辆自主导航的多传感器数据磁合方法.首先分析了车辆自主导航过程的态势与威胁,建立了车辆行驶某时刻场景模型.然后综合现有各数据融合模型的优势,运用混合、分层的融合结构改进自主行驶的有效性和准确性.最后将该方法集成到湖南大学自主研制的无人驾驶汽车测试平台上.在城市道路的实际场景中,初步实现了基于路线和交通锥形标的自主导航和行驶任务,车辆自主行驶的融合决策准确率可达到97.5%,表明该方法具有可接受的性能.     

基于GPS技术的汽车跑偏量测试方法研究

简要介绍了汽车跑偏量的现有测试方法及其不足,提出运用GPS技术进行跑偏量的测试.在引用GPS测试中有关公式的基础上,推导出基于GPS的汽车跑偏量的计算方法.对某一车辆实际测试和计算的结果表明,采用GPS技术测茸跑偏的方法简单、便捷,能达到相当高的测试精度.     

Effect of minor elements on the creep resistance of Mg-Zn-Mn-(Ca) alloy

Along with alumium, titanium and composite alloys, magnesium alloys have been given much attention by industry for applications such as lightweight automobiles and electronics because of their high strength, low specific density and good damping characteristics. In this paper, creep tests were done with magnesium alloys (Mg-3% Zn-1% Mn, Mg-1.2% Zn-1% Mn, and Mg-3% Zn-1% Mn-0.3% Ca) containing different amounts of Zn to investigate the effect of Zn and Ca on the deformation behavior and the rupture time for Mg alloy creep under elevated temperatures. The alloys were obtained as follows: (1) pure magnesium (9.7 kg) was melted at 720°C in an SF6 atmosphere; (2) the temperature was increased up to 800–820°C after adding 0.3 kg of pure Mn to make the Mg-1% Mn master alloy; (3) the minor element (Zn, Ca) was added to the master alloy; and (4) the magnesium alloy melts were cast into a metallic mold preheated to 150°C. The creep tests were executed under a constant load and temperature to measure the steady-state rate and rupture time of creep. Based on the experimental results, the creep behavior of the alloys seemed to be controlled by dislocation climb at around 0.5∼0.55T_m (T_m; melting temperature). In addition, the results showed that the addition of Ca was effective for increasing the creep resistance of a Mg alloy: the more Zn present in the alloy, the stronger the creep strength of the alloy.     

边坡抗滑桩优化设计

针对现在边坡抗滑桩设计方面的不足之处,提出了一种边坡抗滑桩优化设计方法:对边坡进行有限元分析,找出边坡位移最大位置;在位移最大位置处设置抗滑桩,进行边坡抗滑桩整体有限元分析;根据抗滑桩有限元计算结果进行配筋设计.对该设计理论进行了工程实例验证,结果显示,使用该方法能考虑土体的本构关系、力学概念明确,因而比传统配筋设计方法具有明显的优越性.     

C50T型梁机制砂混凝土的配合比设计

针对机制砂混凝土在桥梁工程上部结构中应用存在疑虑的问题,结合湖南吉茶高速公路建设情况,针对机制砂特性以及粉煤灰对机制砂混凝土性能的影响规律,对C50T型梁机制砂混凝土进行了配合比设计,分析了机制砂混凝土的性能影响因素,优选了施工配合比,并对成型T梁进行了静载试验。结果表明,机制砂完全可以配制出强度和工作性能满足T梁要求的高强混凝土,且具有较好的社会、经济效益。     

基于西班牙规范ROM与中国规范JTS的集装箱码头设计荷载对比

针对集装箱码头设计荷载问题,分析中国规范JTS与西班牙规范ROM关于集装箱码头堆场及码头装卸设备设计荷载的差异,结合其他国际规范,分析其合理性,对应用西班牙规范的集装箱建设项目有所借鉴.