田庄台辽河公路大桥T梁预制施工要点

将阐述田庄台辽河大桥30mT梁的预制施工,总结其施工过程中的关键程序,如:混凝土浇筑、养护、张拉等。     

公路项目建设期利息计算方法进一步研究

对建设期利息计算过程中容易混淆的几个概念进行辨析，用数学方法证明了在项目建设计划、贷款流入的特点、贷款利率确定的条件下，项目建设期贷款利息为项目各年贷款投入比例的线性函数。     

基于改进FUKF的燃气轮机性能退化诊断

针对燃气轮机使用过程中由于工作状态突变导致轮机性能估计困难的问题,提出基于残差相似性的渐消无迹卡尔曼滤波（fading unscented Kalman filter with residual similarity,FUKF-RS）算法,实现燃气轮机健康参数的估计.首先,在普通渐消无迹卡尔曼滤波（fading unscented Kalman filter,FUKF）框架下,构造燃气轮机健康参数估值算法,在测量值估计更新过程中,乘以渐消因子来调节前后时刻的权重,通过强制残差正交来估计渐消因子;然后,利用前后估值时刻残差向量的余弦值表征残差阵的相似度,根据其相似度的大小关系确定残差阵的比例;最后,用该比例值代替算法中的遗忘因子,计算残差阵,实现求解的量化取值.研究结果表明:在燃气轮机状态突变条件下,FUKF-RS算法具有突变状态跟踪能力,参数估值精度比FUKF算法提高了3%左右,普通UKF（unscented Kalman filter,UKF）则不具突变状态跟踪能力;在部件性能缓慢变化时,参数的估计曲线比普通FUKF更平滑,估计精度提高了2%左右.      

小微型客车租赁车辆管理和服务平台数据交换接口研究

本文基于小微型客车租赁行业发展的现状与问题,提出了由行业协会或其他第三方机构建立面向全行业的小微型客车管理和服务平台的设想,定义了企业系统、行业平台、省市平台之间的数据交换接口,包括系统间的通信方式、协议消息结构,给出了车辆基础信息和订单信息二类基础数据的消息结构体实例。     

基于IC卡数据的武汉市轨道交通客流时空特征

为了精准评估武汉市轨道交通运行现状、科学辅助编制轨道交通线网规划与建设规划、探寻运营组织中的潜在问题,通过对全市公共交通IC卡记录以及地理信息数据的融合与挖掘,从全网、走廊、断面等方面量化分析轨道交通发展历程和客流时空分布特征。在此基础上建立职住辨识模型,用于获取典型居住和就业区域的空间分布信息。基于此分析通勤群体的出行时间、距离、范围、方向不均衡性以及换乘等特征,并通过群体出行规律分析城市空间布局。最后对城市轨道交通发展提出建议:建立多样化运营模式,大力发展公共交通一体化换乘,注重轨道交通沿线土地开发利用和配套设施建设,加强各行政区协同发展和鼓励就近就业等。     

Product Quality Evaluation Method Based on Product Gene Theory

Traditional quality inspection based product quality evaluation method with complex process has high operating cost and requires more professional knowledge. To remove the above limitation, this paper leads product gene theory into product quality evaluation. Methods of quality influencing factors based modeling and encoding are established. Combined with similarity theory and product gene theory, a product gene similarity analysis based quality evaluation method is proposed. The proposed method is low cost, operates easily and requires less specialized knowledge. A case study is conducted to prove the correctness and feasibility of this method.     

Structural Optimization of Hatch Cover Based on Bi-directional Evolutionary Structure Optimization and Surrogate Model Method

Weight reduction has attracted much attention among ship designers and ship owners. In the present work, based on an improved bi-directional evolutionary structural optimization (BESO) method and surrogate model method, we propose a hybrid optimization method for the structural design optimization of beam-plate structures, which covers three optimization levels: dimension optimization, topology optimization and section optimization. The objective of the proposed optimization method is to minimize the weight of design object under a group of constraints. The kernel optimization procedure (KOP) uses BESO to obtain the optimal topology from a ground structure. To deal with beam-plate structures, the traditional BESO method is improved by using cubic box as the unit cell instead of solid unit to construct periodic lattice structure. In the first optimization level, a series of ground structures are generated based on different dimensional parameter combinations, the KOP is performed to all the ground structures, the response surface model of optimal objective values and dimension parameters is created, and then the optimal dimension parameters can be obtained. In the second optimization level, the optimal topology is obtained by using the KOP according to the optimal dimension parameters. In the third optimization level, response surface method (RSM) is used to determine the section parameters. The proposed method is applied to a hatch cover structure design. The locations and shapes of all the structural members are determined from an oversized ground structure. The results show that the proposed method leads to a greater weight saving, compared with the original design and genetic algorithm (GA) based optimization results.     

Multi-Band Hybrid Mobile Phone Antenna Based on Electromagnetic Coupling

This research presents a multi-band hybrid mobile phone antenna based on electromagnetic coupling,which can be applied to mobile handheld devices, occupying a small board space of 39.7 mm × 15.6 mm on the system circuit board. By adding resonant and coupled branch instead of multi-feed on the traditional bent antenna,this design provides four wide operating bands of 0.772—0.998 GHz, 1.540—1.600 GHz, 1.680—2.270 GHz and2.300—2.690 GHz with the hybrid feature of planar inverted-F antenna(PIFA), L-shape, U-shape and S-shape structures, which cover nine-band, i.e., GSM850, GSM900, GPS1575, DCS1800, PCS1900, IMT200, LTE2300,LTE2600 and Blue Tooth/Wi-Fi. Ansoft software HFSS is used in this research to make the antenna performance better and the operating principle of the proposed antenna is described in detail. Result of simulation reveals that the maximum gains of these four wide bands are 2.20,-0.99, 4.01 and 4.05 dBi, respectively. Moreover, this research also tests the return loss(S11) of the fabricated antenna with the vector network analyzer and the result is in accordance with the simulation result on the whole. There are four wide resonant frequencies which cover nine-band of wireless wide area network(WWAN), wireless local area network(WLAN) and long term evolution(LTE), when the available bandwidth is better than 6 d Bi return loss.     

Catalytic Combustion of Lean Methane Assisted by Electric Field over Pd/Co<Subscript>3</Subscript>O<Subscript>4</Subscript> Catalysts at Low Temperature

A series of Pd/Co₃O₄ catalysts were prepared by Self-Propagating High-Temperature Synthesis (SHS) method in this study, and electric field was applied for catalytic combustion of lean methane over Pd/Co₃O₄ catalysts at low temperature. When electric field was applied, the catalytic combustion performance of Pd/Co₃O₄ catalysts was greatly improved, and the application of electric field could reduce the load of active element Pd to some extent while maintaining the same efficiency. Based on experimental tests and the analysis results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H₂-temperature-programmed reduction (H₂-TPR) and in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS), the mechanism of catalytic oxidation of CH₄ over Pd/Co₃O₄ catalysts in electric field was proposed. The catalytic combustion of CH₄ occurs only when the temperature is higher than 250 °C normally, but when electric field was applied, the whole process of CH₄ oxidation was promoted significantly and the reaction temperature was reduced. Electric field could promote the reduction of the support Co₃O₄ to release the lattice oxygen, resulting in the increase of PdO_x and the surface chemisorbed oxygen, which could provide more active sites for the low-temperature oxidation of CH₄. Furthermore, electric field could accelerate the dehydroxylation of CoOOH to further enhance the activity of the catalysts.