软土地基堆载极限高度的计算分析

对软土地基堆载极限高度进行了塑性极限分析，得出了计算公式。分析了公式中各项的物理意义并结合工程实例对新公式与原有公式进行了对比。     

抗疏力固化土的室内击实试验研究

文章通过分析抗疏力固化土室内击实试验和无侧限抗压强度试验,探讨抗疏力固化材料的不同掺量对抗疏力固化土最大干密度和最佳含水量的影响,及其对抗疏力固化土无侧限抗压强度的影响.     

装配式混凝土梁钢套筒锚接接头抗弯性能研究

装配式结构凭借其施工质量有保障、生产效率高的优点发展迅速,但由于接头处受力的不连续性和不确定性,使得接头成为结构的薄弱环节。为了确保装配式结构安全推广和应用,采用模型试验和数值模拟相结合的方法,对混凝土梁钢套筒锚接接头的抗弯性能和破坏模式进行研究。结果表明： 1）接头的受力过程分为线弹性、梁身混凝土开裂、钢筋与锚固胶滑移破坏等几个阶段; 2）接头最终的破坏形式是锚接钢筋与锚固胶之间的滑移破坏,结构破坏时钢筋应力接近其屈服强度,表明接头可以提供足够的锚固力; 3）可以采用黏聚力模型模拟钢套筒锚固接头抗弯受力过程,通过调整接头钢筋根数和直径可以满足不同截面大小的结构受力要求,可为该接头在装配式地下连续墙中的应用提供可能。     

Generalization of Results of Computations and Natural Experiments at Steel Parts Quenching

IntroductionThepaPerpresentsthegenera1izationofresultsofnumericalcomputationsandnaturalexperimentsbasedonthesimilaritytheoryandtheoryofregularthermalconditions.Thenumericalcomputationshasbeenmadeonthebasisofsolvingequationsofnon-stationarythermalconductivityandthermoplaSticity.Thegeneralizationofresultsliesinthefactthatwefoundadimensionlessformulaforthedeterminationofthetimeofreachingthemaximumcompressionstressesonthesurfaceofp8rtstobequenched.ThepatstobequenchedaredividedintothreegrouPs:pla…     

成层软土路基极限填筑高度研究

文章依托某线路工程,分析软土路基的失稳机理,探讨线路工程穿越软土区时,成层软土路基可行的极限填高计算方法。通过填高与稳定性的横向和纵向分析得出路基的极限填筑高度,再用数值法计算由填高产生的路堤和路基内位移分布。研究表明,用整体稳定性确定成层软土的极限填筑高度是可行的。     

基于体验式教育的航运船员群体凝聚力研究

本文探讨了通过体验式教育来提升航运船员的凝聚力,并开展对比实验。实验结果表明,体验式教育提升了船员的凝聚力,这直接关系着船员稳定和航运安全。因此,采取体验式教育模式有利于培养和激发航运船员群体的团队精神,加强航运效益,对于远距离运输有着积极影响。     

Development of a maximum likelihood regression tree-based model for predicting subway incident delay

This study aims to develop a maximum likelihood regression tree-based model to predict subway incident delays, which are major negative impacts caused by subway incidents from the commuter’s perspective. Using the Hong Kong subway incident data from 2005 and 2009, a tree comprising 10 terminal nodes is selected to predict subway incident delays in a case study. An accelerated failure time (AFT) analysis is conducted separately for each terminal node. The goodness-of-fit results show that our developed model outperforms the traditional AFT models with fixed and random effects because it can overcome the heterogeneity problem and over-fitting effects. The developed model is beneficial for subway engineers looking to propose effective strategies for reducing subway incident delays, especially in super-large-sized cities with huge public travel demand.     

Minimum sample size for extreme value statistics of flow-induced response

Extreme value statistics are one way to determine the maximum design loads for systems in extreme conditions, such as operational loads experienced by ships. Accurate predictions typically require large sample sizes, which are not always possible to obtain. Conversely, small sample sizes lead to more variation in the predictions. Increasing the sample size improves the variance to a desired range. The proposed method aimed to estimate a minimum sample size for an extreme value process by specifying and obtaining an acceptable variance. Minimum sample sizes for extreme value statistics depend on the distribution's behavior, so the method proposed here was designed for use before and during measurements. To test the proposed method, the response of a cantilever fin with a varying angle of attack was measured. The proposed method was able to estimate minimum sample sizes for several distributions. Accuracy was demonstrated by randomly drawing measured and simulated samples.     

信号词与英语听力学习的研究

英语听力学习是一个复杂的过程,影响英语听力学习的因素众多,其中对于语言微技能的训练非常重要。信号词是语篇衔接和连贯理论中的一个小方面,掌握好信号词、增强语言微技能的训练对于学生听力理解能力的提高有着非常重要的作用。     

A maximum entropy-least squares estimator for elastic origin-destination trip matrix estimation

In transportation subnetwork-supernetwork analysis, it is well known that the origin-destination (O-D) flow table of a subnetwork is not only determined by trip generation and distribution, but also a result from traffic routing and diversion, due to the existence of internal-external, external-internal and external-external flows. This result indicates the variable nature of subnetwork O-D flows. This paper discusses an elastic O-D flow table estimation problem for subnetwork analysis. The underlying assumption is that each cell of the subnetwork O-D flow table contains an elastic demand function rather than a fixed demand rate and the demand function can capture all traffic diversion effect under various network changes. We propose a combined maximum entropy-least squares estimator, by which O-D flows are distributed over the subnetwork in terms of the maximum entropy principle, while demand function parameters are estimated for achieving the least sum of squared estimation errors. While the estimator is powered by the classic convex combination algorithm, computational difficulties emerge within the algorithm implementation until we incorporate partial optimality conditions and a column generation procedure into the algorithmic framework. Numerical results from applying the combined estimator to a couple of subnetwork examples show that an elastic O-D flow table, when used as input for subnetwork flow evaluations, reflects network flow changes significantly better than its fixed counterpart.