基于损伤累积效应的半潜式平台结构疲劳分析方法

采用简化法对半潜式钻井平台的疲劳损伤和应力范围进行分析,并通过平台结构疲劳谱闭合分析得到波浪谱的短期分布密度函数,根据Miner线性累积疲劳损伤准则求解平台整体疲劳损伤。研究半潜式钻井平台在极端海况下的疲劳损伤对其疲劳寿命的影响,以及历史疲劳损伤对在用半潜式钻井平台的剩余寿命产生的影响,并提出基于历史损伤累积效应和极端海洋环境载荷作用的半潜式钻井平台剩余寿命分析方法。     

丙烯酰胺的生产工艺研究

在丙烯酰胺的实际生产过程中,研究催化剂再生条件及使用时间、预热器温度、反应压力、原料配比、物料反应时间等因素对丙烯酰胺收率的影响。结果表明,最佳的催化剂再生条件为氢氧化钠溶液浓度为15%、再生36 h、催化剂使用时间为5~13 d、预热器温度为90℃、反应压力为0.35 MPa、反应水腈比为7∶1、物料反应时间为0.7 h。在此工艺条件下,丙烯酰胺收率可达98.00%以上,为后期聚丙烯酰胺的生产奠定基础。     

Kinetic theory for aquatic animal distribution simulation

Identifying the underlying mechanisms that influence the spatial patterns in populations improves the forecasts of the alternative management strategies on the spatial dynamics of the populations, which are critical for assessing and managing the fisheries and improving the water resource management. This paper described a new approach of the numerical model for the prediction of the aquatic animal distribution in the flows. The model was developed based on the kinetic theory of gases, the mechanism of the aquatic animal movement and the flow hydrodynamic patterns. The model was validated using the available experimental data and an acceptable agreement was obtained. A comprehensive parameter study was then conducted to help understand the impact and the sensitivity of each parameter to the aquatic animal distribution. The promising results of the model reveal the prospect of applying this model to the reliable prediction of the aquatic animal distribution within a relatively large water area.     

Investigation of Barree-Conway non-Darcy flow effects on coalbed methane production

Coalbed gas non-Darcy flow has been observed in high permeable fracture systems,and some mathematical and numerical models have been proposed to study the effects of non-Darcy flow using Forchheimer non-Darcy model.However,experimental results show that the assumption of a constant Forchheimer factor may cause some limitations in using Forchheimer model to describe non-Darcy flow in porous media.In order to investigate the effects of non-Darcy flow on coalbed methane production,this work presents a more general coalbed gas non-Darcy flow model according to Barree-Conway equation,which could describe the entire range of relationships between flow velocity and pressure gradient from low to high flow velocity.An expanded mixed finite element method is introduced to solve the coalbed gas non-Darcy flow model,in which the gas pressure and velocity can be approximated simultaneously.Error estimate results indicate that pressure and velocity could achieve first-order convergence rate.Non-Darcy simulation results indicate that the non-Darcy effect is significant in the zone near the wellbore,and with the distance from the wellbore increasing,the non-Darcy effect becomes weak gradually.From simulation results,we have also found that the non-Darcy effect is more significant at a lower bottom-hole pressure,and the gas production from non-Darcy flow is lower than the production from Darcy flow under the same permeable condition.     

高速公路路基、桥梁与隧道的衔接方案研究

对于高速公路建设项目而言,路基、桥梁与隧道的衔接处理是至关重要的一步,它不仅影响着高速公路的美观与行车舒适度,同时也影响着日后的安全运营,因此优化高速公路的路基、桥梁与隧道衔接方案是必要的。本文先简单地介绍桥隧连接施工技术,再针对工程建设中因断面宽度不同而导致的衔接问题,分析其结构组成及产生的原因,阐明对路基、桥梁与隧道衔接的优化处理,达到安全、适用和美观的效果,把因衔接问题带来的不良后果降到最低。     

基于科教融合的应用型本科实践教学改革研究

本文首先分析了实践教学环节在应用型人才培养中的重要作用,并分析了目前应用型本科院校在实践教学上存在的主要问题,在此基础上,结合"科教融合"的基本概念,对应用型本科院校"科教融合"的理念进行了解析,并分析得出"科教融合"是提高应用型本科院校实践教学质量的有效方法,最后提出了应用型本科院校"科教融合"实践教学的改革方案,并以宁波工程学院交通运输专业为例进行了案例分析。     

姚培谦家世生平考论

姚培谦,清初著名学者,松江人,主要活动于雍正、乾隆两朝。其一生侘傺不偶,境遇轗轲,却能泰然处之,恬淡忘机,气节人品为时所重。姚培谦出身金山望族,其家族德业为乡邦式,崇文尚学、风雅仁爱之宗风延播子孙,对姚培谦之人生观、学术观、文学观之形成皆有影响。     

土木工程施工中加强项目成本管理措施的探讨

随着我国经济的发展,每年各地都有大量的在建工程,无论是从国家利益还是从企业利益考虑,加强项目成本管理,用最小的成本投入,就能获取最大的效益.     

建筑用抗震钢HRB400EⅢ级钢筋焊接接头的低周疲劳性能

采用轴向应变控制方法,在MTS809拉扭复合疲劳试验机上开展了HRB400EⅢ级钢筋母材及焊接接头的低周疲劳试验,获得了母材及焊接接头的低周疲劳性能,如循环应力响应特征、循环应力-应变关系以及寿命预测公式等.通过断口电镜扫描发现,HRB400EⅢ级钢筋焊接接头的裂纹萌生于试件表面,且存在多处裂纹源.研究结果表明,焊接接头与母材的低周疲劳寿命及微观断裂机理方面均存在明显差异,并从力学性能变化的角度对引起差异的原因进行了解释.     

基于多源信息和粒子群优化算法的下肢运动模式识别

为了提高人体下肢多运动模式识别的准确性,提出一种基于多源信息和粒子群优化算法-误差反向传播(PSO-BP)神经网络的识别方法.建立下肢多源信息采集系统,该系统由下肢表面肌电信号、髋关节角度、髋关节加速度组成.选择肌电信号偏度、峭度和功率谱比值为肌电信号特征,髋关节角度细分模式均值比为腿部角度信号特征,加速度标准差、能量峰值、两轴相关性系数为髋关节加速度特征.按照主成分分析(PCA)方法融合上述特征值,利用PSO-BP进行识别.实验结果表明:该方法识别率为95.75%,平均识别时间为1.234 8s.