拉弯扭共同作用下RC构件极限扭矩试验研究

根据８根钢筋混凝土拉弯构件扭强度的试验结果,对拉弯扭构件的破坏形态,纵筋及箍筋的应力应变规律等问题进行了分析研究。论文以变角桁架理论为基础,推导出拉弯扭构件相关方程,提出了在较大轴拉力情况下的计算拉弯扭构件极限扭矩的实用公式。     

NGI研发策略与单层用户数据交换平台体系结构

以四川省网络通信技术重点实验室有关NGI(下一代因特网)体系结构及相关技术研究为背景,较全面地探讨了NGI研发策略及与NGI体系结构相关的问题.重点是实验室有关NGI的研究:“骨干通信子网优先,外延次之(BSF-OES)”的NGI研发策略;骨干通信子网的单层用户数据交换平台体系结构(SUPA);面向以太网的物理帧时槽交换( EPFTS)技术;未来的开放式网络与应用服务模型(ONASM).还讨论了基于SUPANET(单层用户数据交换平台体系结构网络)框架如何迎接Intemet面临的高速交换、服务质量保障、网络安全和移动性问题的挑战和实现NGI目标的相关问题.     

140 kW高性能集成式电驱动产品开发

自主研发的140 kW高性能汽车电驱动系统,实现多项技术突破,包括突破高集成度低成本电驱动产品设计、高性能电机和逆变器产品设计、高逆变效率和整车抖动抑制电机控制、高安全、高可靠、高鲁棒性电驱动产品设计、自动化标定和测试系列集群技术创新.实现电机比功率为4.1 kW/kg,逆变器功率密度为35 kW/L,三合一电驱动系统...     

双电机混合动力车辆串并联驱动模式切换控制方法

为实现双电机混联构型混合动力车辆(HEV)的串并联切换控制,通过对双电机混联构型进行串并联驱动模式分析,提出一种通过三动力源协调控制的无动力中断切换方法.将串联到并联切换过程分为发动机工作点转移、离合器结合、动力源切换3个阶段,将并联到串联行驶切换过程划分为动力源切换、离合器打开、发动机工作点转移3个阶段,并通过仿真分...     

基于电动汽车电池加热器的控制方法优化

电动汽车电池在低温加热过程中,针对加热器的档位频繁切换和由此引发的冲击电流会缩短电池寿命的问题,提出了基于目标加热水温寻找加热平衡档位的控制方法。以目标加热水温为控制目标,由最高档位开始寻求当前条件下的平衡档位,在平衡档位下加热器水温可以长时间控制在目标值附近。对比优化前的实车测试结果,整个加热过程加热器的档位切换次数由33次减少到5次,加热时间也由57min缩短到40min,优化效果显著。     

船用低速柴油机实时仿真模型开发及应用

以某型小缸径船用低速柴油机为对象,基于该柴油机一维性能模型,开展实时仿真模型的快速开发和标定。比较了简化后实时仿真模型与原性能模型的计算时间和仿真精度。应用该模型在硬件在环测试平台上测试新研制的柴油机控制器。试验结果表明,该模型可正常接收和反馈正确的控制器指令和柴油机运行参数,满足电控系统硬件在环测试的试验要求。     

Valuing cargo flexibility in oil transportation

The seaborne oil transportation market is served by two main types of vessels—crude oil tankers and product tankers. Product tankers are designed to move refined oil products, yet they can also opportunistically carry ‘dirty’ products such as crude and heavy fuel oil, subject to the cost of tank cleaning when re-entering the clean products trade. We apply an entry-exit real option model with a stochastic freight rate differential to derive optimal triggers for switching between the two cargo types and estimate the value of the switching option. We show that the value of active switching has grown over time, and generally exceeds the additional construction cost of a product tanker. Our findings are important both from a practical point of view and for our understanding of market integration in the tanker freight market. Specifically, shipowners can use our model as a basis for optimizing chartering policy for clean product tankers. We also show that there are periods where the dirty market is persistently stronger, and discuss the possible reasons for such apparent inefficiencies.     

Decision tree method for modeling travel mode switching in a dynamic behavioral process

As road congestion is exacerbated in most metropolitan areas, many transportation policies and planning strategies try to nudge travelers to switch to other more sustainable modes of transportation. In order to better analyze these strategies, there is a need to accurately model travelers’ mode-switching behavior. In this paper, a popular artificial intelligence approach, the decision tree (DT), is used to explore the underlying rules of travelers’ switching decisions between two modes under a proposed framework of dynamic mode searching and switching. An effective and practical method for a mode-switching DT induction is proposed. A loss matrix is introduced to handle class imbalance issues. Important factors and their relative importance are analyzed through information gains and feature selections. Household Travel Survey data are used to implement and validate the proposed DT induction method. Through comparison with logit models, the improved prediction ability of the DT models is demonstrated.     

海底电缆在敷设中的受力分析

探讨了海底电缆（海缆）在敷设过程中的受力情况,分析了作用在海缆上张力的性能、数值计算及其可控性,从而提出了以控制海缆的张力达到控制海缆敷设作业的思路。对海缆敷设作业有一定参考价值。     

舰艇开关电源的低频传导干扰建模与仿真

开关电源的电磁干扰是舰艇电磁兼容工程中的典型问题.针对舰艇电网上出现的低频传导干扰现象,着重探讨开关电源低频传导发射及其对电网的影响.详细分析了开关电源低频传导干扰的形成机理,并为开关电源建立了低频传导发射模型以计算电网上的低频谐波干扰.在此基础上,借助软件工具对开关电源的低频传导干扰进行模拟仿真,分析了流回到电源线上的传导发射电流以及谐波畸变情况,从而实现对开关电源低频传导干扰的数值预测.