几种光伏发电MPPT技术性能的仿真比较

文章基于同一基准的光伏发电变换器电路,在Matlab／Simulink平台下对扰动观察法、电导增量法等多种MPPT算法进行了仿真分析,在误判、稳态振荡、动态性能、累计发电量等方面进行了比较。为使仿真更接近实际情况,在仿真中采用了随时间线性变化的光照作为外部环境条件。此外,在理论上分别对扰动观察法与电导增量法做了较深入的数学解释和几何解释两方面的比较。仿真结果和理论分析均表明,二者并无显著的差别。     

Willingness to pay for public transportation options for improving the quality of life of the rural elderly

Transportation for the rural elderly is an increasing concern as baby boomers age and young people continue to exit rural communities. When the elderly are no longer able to drive, they rely on alternative forms of transportation, including public transportation systems. Currently, such systems are usually not good substitutes for driving a private car, especially in rural areas. Because expanded rural transportation systems would likely be funded by taxpayers, an understanding of their preferences and willingness to pay (WTP) for non-medical transportation options is essential. To help understand WTP and preferences, a choice experiment survey was administered to taxpayers in three counties (Atascosa, Polk, and Parker) in Texas. Results indicate taxpayers’ value transportation services for the elderly and are willing to support them. They value more flexible options over base levels of the attributes presented, but they may not always prefer the most flexible options. Respondents’ WTP for the same transportation attribute was similar across counties, but differences in socio-demographic coefficients suggest that transportation systems may need to be customized to meet local needs. Furthermore, county residents’ WTP may not cover the cost of desired improvements to the transportation systems.     

某水库库区公路改建设计方案探讨

文章以某水库库区公路改建工程为实例,探讨了水库库区公路勘察设计的原则和重点,并从保证公路运营安全和控制工程造价角度对该库区公路改建设计方案进行了综合比选。     

论勘测设计企业的办公自动化应用

通过对我国办公自动化的发展过程及部属应用的总体原则,阐述了针对勘测设计企业的运作方案.     

船舶操纵模拟器在船舶通航安全评估中的应用

船舶日趋大型化，导致原有航道和港口不能满足大型船舶的安全通航或靠泊要求。针对转向频繁、转角大、掉头区域不足、水深较浅的高难度航道，在船舶操纵模拟器上实施大型船舶通航安全的模拟试验，并对结果进行评估，进而对狭航道的设计或改造工程进行验证，并提出通航安全方面的合理化建议。     

多方合力 加快江苏水运强省步伐

在工程建设过程中,常常涉及到高程测量。本文结合工程实际,简要阐述新三角高程测量法。     

中小型船舶固定灭火系统的选配与检验

本文通过对船舶各类固定灭火系统的特性比较,根据规范的要求及经验总结,对不同类型的船舶及其不同的处所的固定灭火系统的选配,提出合理的建议,并对船舶同定灭火系统的检验,总结出检验要点。     

海洋工程综合检测船的研究与设计

简要介绍了海洋工程综合检测船（海洋石油709）在自主研发设计工作中的主要关键技术性能、作业技术性能、作业安全保障技术性能、船型主要技术特点、电力推进应用技术研究、动力定位系统技术研究、船舶基本概况等。     

浅谈公路工程测量监理工作要点

做好公路工程测量监理工作尤为重要,结合工作实际,本文从控制测量监理和施工测量监理两个方面加以阐述,总结出公路工程测量监理工作要点,为广大测量监理工程师提供参考。