水稳碎石沥青路面基层最小厚度研究

通过对水泥稳定级配碎石材料进行弯拉疲劳试验,得到了水泥稳定级配碎石的疲劳方程;建立不同结构层厚度下的路面结构模型,分析了水稳碎石基层沥青路面在不同标准轴载作用次数下的结构响应,确定了弯沉和结构疲劳寿命分别控制下的水稳碎石基层最小厚度,面层厚度为5、10、15cm时,基层最小厚度分别为32.3、34.2、36.5cm。基层最小厚度结果表明,面层厚度5cm时,基层最小厚度的有效控制指标为结构层疲劳寿命;面层厚度10、15cm时为弯沉。     

新疆多年冻土地区桥涵病害调查及防治措施

结合新疆多年冻土地区现有公路涵洞、过水路面和桥梁技术状况的调查结果,分析了该地区桥梁和涵洞病害的成因,提出了桥涵结构物病害的防治原则,设计上的处理措施,具有一定指导性。     

基于QUAKE/W的边坡地震动力响应分析

以QUAKE/W为手段,结合边坡工程实例,从动力角度对地震作用下边坡体稳定性和动力响应进行研究,用有限元的方法给出地震作用下的边坡位移量和应力分布。结果表明,在地震作用下,边坡的最大水平位移量发生在边坡的中上部;最大剪应力集中在坡脚附近,边坡体处于不稳定状态,建议开挖过程中采取相应的支护措施。最后再将QUAKE/W模型导入SLOPE/W中把有限元法与极限平衡法相结合计算安全系数,同时给出最小平均安全系数的计算方法,并以其作为边坡稳定性的评价指标。     

基于三阶段最小二乘法探究诱增交通量

在诱增交通量的预测中,中国现有统计数据在精度和广度上的局限性,容易造成计算结果存在遗漏变量偏误和测量误差偏误;同时变量之间的相关性容易导致计算结果存在联立性问题。为克服这些问题,采用工具变量法中的三阶段最小二乘法探讨道路供给与交通需求之间的关系。基于国家统计数据库数据,选择车辆出行距离、民用汽车拥有量和交通拥堵水平三个内生变量构建联立方程模型,采用三阶段最小二乘法对联立方程进行估计,并给出短期、长期弹性系数的求解方法。结果表明,道路建设会导致车辆出行距离增加,不能解决中国城市交通拥堵问题,而大力发展公共交通可以降低交通拥堵水平。     

膨胀土表面裂隙参数数据处理方法研究

利用最小二乘和偏最小二乘回归方法,对比分析了干湿循环作用下膨胀土表面各裂隙参数之间的关系,并导出了相应的公式.结果表明;偏最小二乘回归方法比最小二乘法的拟合参数关系更接近实测值,在自变量具有强相关性的情况下建立的计算模型,更为有效地解决变量间多重共线性问题,对岩土参数问题的分析具有指导意义.     

对船舶雷达盲区测定的探讨

一、船舶雷达盲区测定的必要性1.根据IMO海安会MSC.192（79）决议—经修订的雷达设备性能标准建议案,对雷达最小距离要求如下：当自身船舶航速为零,雷达天线高度为海面以上15米且海面平静时,应在距天线位置40米的最短水平距离1海里范围内,在不改变距标度转换开关以外的控制功能的设定情况下探到导航浮标;如安装了多根天线应自动进行距离误差补偿。2.根据《1972国际海上避碰规则》第6条2款的规定：对备有可使用的雷达的船舶,还应考虑：（1）雷达设备的特性、效率和局限性;（4）在适当距离内,雷达对小船、     

Fabrication and Interfacial Structure of Ni-YSZ-LSM Porous Scaffold for Solid Oxide Fuel Cells

A novel process route using tape casting and stacking for fabricating porous scaffold of solid oxide fuel cells (SOFC) was demonstrated. The linear shrinkages of anode (Ni-YSZ, YSZ stands for 3% Y_2O_3(mole fraction) stabilized ZrO_2) and cathode (LSM-YSZ, LSM stands for La_(0.8)Sr_(0.2)Mn0_3) were optimized to be uniform with that of electrolyte during sintering, by controlling the content of pore former. The micromorphology and interface microstructure of the cross-section of the porous scaffold were observed by optical microscope and scanning electron microscope, respectively. The element distribution and phase composition were analyzed by energy dispersive spectrometer and X-ray diffraction, respectively. The results showed that the porous scaffold with regular pore shape and high specific surface area was obtained after sintering at 1 350℃. The fabricated porous scaffold had defect free interfacial structures due to the uniform shrinkage of anode, cathode and electrolyte layers. In addition, it was shown that diffusions of Zr, Ni and La caused a progressive boundary between YSZ, Ni-YSZ and LSM-YSZ layers. The interface between anode and electrolyte (Ni-YSZ/YSZ) was mainly composed of Ni, YSZ and a small amount of NiO, and the interface between cathode and electrolyte (LSM-YSZ/YSZ) was mainly composed of YSZ, LSM and a small amount of La_2Zr_2O_7.     

基于遗传算法的近红外光谱建模样品集优化研究

探讨遗传算法优化方法在南丰蜜橘内部品质可溶性固形物的建模集样品选择中的应用,根据优化结果建立了南丰蜜橘可溶性固形物的快速无损检测数学模型。研究选择的波长范围为350—1800nm,应用遗传算法优化建模集样品,优化后建模集样品数量由89个减少到36个,累积变异系数达到99．99％,交互验证均方根误差达到最小。研究结果表明：优化后的建模样品数量大大减少,且保证了南丰蜜橘可溶性固形物的快速无损检测数学模型的稳定性。     

Least Squares Support Vector Machine Based Real-Time Fault Diagnosis Model for Gas Path Parameters of Aero Engines

Least squares support vector machine (LS-SVM) is applied in gas path fault diagnosis for aero engines.Firstly,the deviation data of engine cruise are analyzed.Then,model selection is conducted using pattern search method.Finally,by decoding aircraft communication addressing and reporting system (ACARS) report,a real-time cruise data set is acquired,and the diagnosis model is adopted to process data.In contrast to the radial basis function (RBF) neutral network,LS-SVM is more suitable for real-time diagnosis of gas turbine engine.     

A study on the degree of barrier coverage in wireless sensor networks

Recently, the barrier coverage was proposed and received much attention in wireless sensor network (WSN), and the degree of the barrier coverage, one of the critical parameters of WSN, must be re-studied due to the difference between the barrier coverage and blanket coverage. In this paper, we propose two algorithms, namely,local tree based no-way and back (LTNWB) algorithm and sensor minimum cut sets (SMCS) algorithm, for the opened and closed belt regions to determine the degree of the barrier coverage of WSN. Our main objective is to minimize the complexity of these algorithms. For the opened belt region, both algorithms work well, and for the closed belt region, they will still come into existence while some restricted conditions are taken into consideration.Finally, the simulation results demonstrate the feasibility of the proposed algorithms.