汽车空调系统改进试验研究

针对某汽车在适应性试验中出现的空调系统制冷效果不佳问题,对其进行了整车降温试验和蒸发器表面热成像试验,确定了导致制冷效果不佳的主要原因,并对该汽车空调系统采取了优化蒸发器内部管道流向、调整蒸发器表面温度传感器横向位置及更改放大器断通值范围等改进措施。实施改进措施后,蒸发器表面温度均衡,空调高、低压管路压力正常,制冷效果良好。     

车辆传动装置密封环摩擦状态辨识的试验研究

为探讨车辆传动装置的密封环早期失效的原因,掌握密封摩擦状态转变规律及其对密封性能的影响,利用传动装置密封性能试验台,测得摩擦因数-工况参数曲线(即f-G曲线),研究了不同油温条件下密封摩擦状态的变化规律,分析了密封环摩擦状态转变对密封性能的影响.结果表明,在设定的试验条件下,通过f-G曲线可揭示密封环在高速重载工况下摩擦状态转变规律及其辨识特征;密封环摩擦状态的转变对泄漏量的影响有限,而对密封环温升的影响较为显著.     

高速三体船片体构型数学表达和兴波阻力计算

高速三体船以其优良的减阻性能、耐波性和稳性而具有广阔的军事和商业应用价值。尽管已有大型实船付诸应用,但高速三体船型的兴波阻力预报和减阻设计问题并未解决,而这又是高速三体船实际应用的重要环节。采用帐篷函数法进行高速三体船的片体构型设计,并据此计算各船型参数。将改进的线性兴波阻力数值算法应用于高速三体船的兴波阻力计算,根据模型试验结果,验证了计算方法的有效性。     

门座起重机刚柔耦合动力学仿真研究

基于虚拟样机技术,针对门座起重机刚柔耦合系统及钢丝绳柔性,利用UG,ADAMS与AN-SYS联合建模,进行起升、变幅和回转工况过程的动态仿真,为门座起重机的设计和分析提供了一种新方法.结果表明,该仿真模型能准确模拟门座起重机各作业工况运动和动态响应.     

Preparation and characterization of a new kind of nano-rod shaped polycarboxylate slump-retaining admixture using for concrete

A new kind of nano-rod shaped polycarboxylic acid slump-retaining agent was synthesized. Transmission electron microscope (TEM) experiment showed that the nano-rod was bound together as macromolecular aggregates in solution. Application performance studying suggested that this kind nano-sized polymer material had excellently plasticity-retaining performance in cement-based materials and could improve endurance performance of hardened cement-based materials distinctly. The concrete with an initial slump of 2?C9 cm could achieve 3 h plasticity-retaining performance with the help of this kind nano-rod. The product had extremely wide application value in the market.     

Experimental study on mechanical behavior of box-brace to box-column foot joints

This paper presents results of three tests carried out to study the mechanical behavior of foot joints used in the tower boiler steel frame. Each foot joint consists of a box column and a box brace. These three specimens have different connection types or different details of stiffeners. The tests are carried out by using the large multi-function structural experiment system WAW-1000J. The load-displacement curves and the strain distribution are measured during the tests. The mechanical behavior of foot joints under adverse load cases is analyzed. The safety of these three specimens under design load is assessed. The strength and deformation of different joints are compared. The results indicate that connection types or details of inner stiffeners have effects on strength and failure mode and that the specimen with end-plate connection can optimize the strain distribution along the height of brace web and can change the force transfer mechanism between column and brace. In addition, a finite element model of the specimen is conducted and numerical results generally agree well with the test results. The work in this paper provides a base for further analysis on the performance of joint used in the tower boiler steel frames.     

基于物联网技术的高边坡监测系统研究

高边坡滑坡是高速公路工程中常见的一种地质灾害, 对高速公路的安全运营造成严重威胁。 为了有效地监测和预警高边坡的稳定性和变形情况, 以申嘉湖高速公路某高边坡为例, 采用有限差分软件 FLAC3D 对高边坡进行了数值模拟, 计算了边坡稳定性和变形特征, 并构建了基于物联网监测技术的高边坡监测系统。 该系统长期运行并保持稳定, 相比人工监测, 高边坡监测系统具有实时性、 智能性、 可靠性等优点, 为高边坡工程的智能化管理提供了一种新的思路和方法。     

基于非集计模型的居民出行方式选择行为研究

基于ML模型的基本理论与建模方法,利用2009年济南市居民出行调查数据,对影响城市居民出行方式选择的因素进行了分析,确定了影响居民出行方式选择的特性变量,建立了居民出行方式选择ML模型.研究结果表明:居民出行方式选择与个人属性、家庭属性和出行属性之间有较稳定的关系,通过对影响居民出行方式选择的可控影响因素进行引导和调整,可以达到优化和调整交通方式结构的目的.     

地铁区间隧道穿越京山铁路施工控制技术

北京地铁五号线区间隧道蒲黄榆至天坛东门段在玉蜓桥两侧下穿京山铁路,隧道埋深17 m。为保证既有线运营安全,采用全断面帷幕注浆预加固技术,监控量测结果表明路基沉降可以满足要求。     

舰船水压场信号实时检测方法研究

为了有效地从风浪背景中检测舰船水压场信号,在对大量实测海浪水压场数据和舰船水压场数据分析的基础上,对海浪水压场信号的特性进行了研究,发现海浪水压场信号可用AR模型对其进行描述．从而对海浪水压场信号建立AR模型,计算AR模型的反射系数并提取其欧氏距离作为特征,采用滑动检测法对信号进行实时检测．通过大量实测数据检验其有效性,结果表明,该算法简单,能较好的检测目标信号．