自抗扰控制在船舶自动舵上的应用

本文回顾了船舶自动舵的发展历程,分析了传统自动舵在应用上的不足之处。同时介绍了自抗扰控制器的原理,尝试利用自抗扰技术设计出更理想的船舶自动舵系统。     

旋挖钻机作业装置的动力学分析

由于旋挖钻机质量大、输出扭矩大,所以对旋挖钻机的主要部件进行力学分析十分重要。针对旋挖钻斗钻进过程、回转机构运动过程和变幅机构变幅过程进行了分析,能为旋挖钻机的设计提供一定的理论参考。     

高压共轨柴油机工作过程仿真及性能参数优化

结合4缸柴油机缸内燃烧压力实测数据,利用AVL Boost软件Burn功能分析了燃烧放热规律,获得了模拟柴油机燃烧所需的Vibe燃烧模型参数,建立了模拟柴油机工作过程仿真模型.分析并优化了影响柴油机性能的进排气歧管直径和长度、配气相位、EGR率等性能参数,同时对涡轮增压器进行了匹配计算分析.研究结果表明,利用热力学仿真...     

道路改性沥青及改性剂的选择

通过对不同聚合物改性剂及改性沥青性能的分析,探讨了改性剂的选择要考虑不同气候条件、不同荷载条件、现有加工能力以及工程造价等诸多因素。     

船用钢气割原则工艺及操作要领

氧-乙炔气割工艺广泛应用于船舶制造、船舶修理的钢板、管子切割生产中,文章针对船用碳素结构钢和低合金钢气割原则工艺,介绍了气割操作要领,对从事气割管理和操作的工作人员提供了指导和参考。     

Dynamic user equilibrium with side constraints for a traffic network: Theoretical development and numerical solution algorithm

This paper investigates a traffic volume control scheme for a dynamic traffic network model which aims to ensure that traffic volumes on specified links do not exceed preferred levels. The problem is formulated as a dynamic user equilibrium problem with side constraints (DUE-SC) in which the side constraints represent the restrictions on the traffic volumes. Travelers choose their departure times and routes to minimize their generalized travel costs, which include early/late arrival penalties. An infinite-dimensional variational inequality (VI) is formulated to model the DUE-SC. Based on this VI formulation, we establish an existence result for the DUE-SC by showing that the VI admits at least one solution. To analyze the necessary condition for the DUE-SC, we restate the VI as an equivalent optimal control problem. The Lagrange multipliers associated with the side constraints as derived from the optimality condition of the DUE-SC provide the traffic volume control scheme. The control scheme can be interpreted as additional travel delays (either tolls or access delays) imposed upon drivers for using the controlled links. This additional delay term derived from the Lagrange multiplier is compared with its counterpart in a static user equilibrium assignment model. If the side constraint is chosen as the storage capacity of a link, the additional delay can be viewed as the effort needed to prevent the link from spillback. Under this circumstance, it is found that the flow is incompressible when the link traffic volume is equal to its storage capacity. An algorithm based on Euler’s discretization scheme and nonlinear programming is proposed to solve the DUE-SC. Numerical examples are presented to illustrate the mechanism of the proposed traffic volume control scheme.     

大牛地气田29#站-塔榆二阀室管网工况调节

大牛地气田产量供应上涨的需求给运行压力较高的29#站-塔榆二阀室管网带来了压力,为确保该管网在保证产量供应的条件下能够安全运行,在分析影响管网流量因素的基础上,分别利用TGNET软件模拟了集气站压力、温度及管线直径与输气量之间的关系,为管网的优化和改造提供依据.     

人工气泡船水动力性能试验研究

文章通过试验途径研究了人工大气泡船的水动力性能,试验包括气泡船流量测试试验、气泡船通气对比试验、气泡船与其原型船静水及波浪中对比试验。结果表明,气泡船充气后阻力能大大下降;对于气泡船有一最经济的充气流量;气泡船在静水及波浪中的综合性能均优于常规船型,特别是阻力下降很多。根据试验结果还分析了气泡降阻的原理:具有一定压力的气泡腔,除了减小船底的摩擦阻力之外,还支撑了艇的一部分重量,减小了艇体的吃水,从而阻力也相应地减少。     

9000DWT化学品船的DNV一人桥楼设计

作为技术进步与自动化的成果,船舶一人桥楼日益受到船东和船级社重视。它既可以减少船员,提高工作效率,又能够改善船舶的安全性。结合9000DWT化学品船的一人桥楼设计,着重介绍了挪威船级社（DNV）NAUT-OC入级符号的设计要求．并从驾驶室的视野、工作环境以及规范强制要求的工作站等各个方面分析了一人桥楼的设计要点和注意事项。     

高等职业院校发展规划编制工作若干问题的思考

发展规划编制工作是高等职业院校实施战略管理的基础性工作,需要科学设计与统筹管理。本文梳理了高等学校战略规划的演进,分析了高职院校战略规划编制的过程模式,就发展规划编制工作的若干问题的有效解析提出了管理建议。