电网电压不平衡下光伏并网逆变器的同步技术

为了保证光伏并网逆变器在电网电压不平衡下可靠地向电网输送功率,需要提高逆变器的同步跟踪能力及动态响应性能。提出一种基于比例积分简化型谐振调节器的锁频环(PISR-FLL)技术。PISR-FLL具有高增益带宽及频率自适应特点,能够从不平衡电网电压中准确快速地估算出基波频率正、负序分量。改进的锁频环(FLL)通过增益系数线性化后不但可以保证频率自适应调节,控制结构也变得简单,易于数字实现。仿真和实验结果表明该PISR-FLL技术精度高,动态性能优越,可以满足不平衡电网条件下电网信号同步跟踪要求。     

A new method for quantitative identification of potential landslide

A growing number of slope hazard and engineering case studies have shown that only one safety factor (SF) can predict landslide occurrence, but cannot identify potentially dangerous landslides, which is the major source of the most destructive landslides. To solve the problem, a safety factor of cohesion (SF_c) is proposed, and an improved slope stability analysis based on two safety factors is presented. Taking a sloping rock mass as a case study, the results showed that when SF_c was less than 1 and the ratio of the cohesive force to the sliding resistance force drops to less than 100%, the slope became a potential landslide. The study suggests a new method for quantitative identification of potential landslides and provides a more reliable safety evaluation index, thus can solve the difficulty of adjustment of potential landslides and provide a more reliable safety evaluation index for engineering.     

Multi-criteria decision support: A case study of Southeast Europe power systems

The power sector has been going through quite turbulent times during the past couple of years. During this time, several long-held tenets of the sector have been rewritten. As new technologies appear and as the surge of renewables dramatically transforms the system, we witness an emergence of new market players and possibilities. With key issues revolving around different problem areas, the importance of taking a multidisciplinary view on forming development strategies proves crucial in achieving desired outcomes. Having a detailed understanding of the dynamics underpinning energy markets is crucial for both decision-makers and investors. Forming a successful development strategy or a policy framework requires reconciling a string of technical, environmental, economic and social factors. Choosing the right combination of policies and technologies could fuel economic growth while still providing secure and affordable energy in line with low-carbon goals. In this light, we take Southeast Europe (SEE) as a practical example and study various questions regarding legal frameworks and development policies of countries in the region. The methodology structure allows considering environmental, economic, technology and policy issues. Each country's electricity sector is evaluated using a comprehensive database, with particular consideration to its affordability, self-reliance and sustainability. This study presents an overview to help clarify some of the aspects behind forming a successful framework capable of making the right decisions for the future.     

低噪音玄武岩纤维微表处在养护维修工程中的应用

为改善传统微表处的噪声污染问题,结合甘肃G30线连霍高速永山段低噪音玄武岩纤维微表处工程,通过对原有路面病害调查、室内试验及现场施工检测等,分析低噪音玄武岩纤维微表处技术的配合比设计及降噪效果。结bs果tr表act明:I,n低or噪de音r玄to武co岩nt纤rol维th微e表pr处ob有le良好of的no降is噪e p效ol果lut及io抗n c水au损se性d能by, t在ra河dit西io地区有一定的适用性。ladYA关oonesna键il-ggyns词nsohiiasas:nneo低dfsbe噪oancrsoti音iaigolstie;n nf微iraoblefe表dpLruia处acvtneii;hoc配urne oo e合nseftf xu比edrpcifrt设sa eecosi计afs slwge;o as性hw,yma-io能snn fodg测iGoos3ooe试0rdbitannesosaGitls a tae n fnisrdbeu,e d frtiuheclimtsdiio cpcrnao op nesefsfrute rrscfutua ccamtiinnomdgnatrdieazecntetheesn rc aotlmilnooodsgn sa. y rnteahhsliryeso z trueaesgn shtcu heli,ten savmnesishdxmt o ihpgaransott iphcooeanrtrwtt atianohidne applicability inexi area.H Kwwmnm     

380g/L噁草酮悬浮剂及其不同桶混助剂配伍室内防除稻田杂草活性试验

温室盆栽法测定除草活性试验结果表明,380g/L噁草酮悬浮剂及其不同桶混助剂配伍对水稻稗草有较好的除草活性,特别是加入桶混助剂GY—Hba S2#的380g/L噁草酮悬浮剂在试验中产生较显著的增效作用。     

硅石牺牲混凝土配合比研究

硅石牺牲混凝土可减少堆芯残骸与混凝土反应的危害性,保证我国核电站的安全运行。结合台山核电站实际情况,通过确定原材料、设计配合比,可配制出符合技术规格及相关标准要求的硅石牺牲混凝土。经性能测试试验验证,该混凝土性能满足施工技术要求。     

金川镍矿高效机械化湿喷混凝土技术的应用

为解决金川镍矿巷道支护过程中喷射混凝土层强度达不到设计要求、施工效率低、回弹率高等问题,开展了推广机械化湿喷混凝土技术的研究和实践,并取得了丰富的研究成果。针对已成功应用在金川镍矿的机械化湿喷混凝土技术,从原材料的选用、配合比设计、设备配套、工艺流程、湿喷关键技术等方面做了详细介绍,可供类似工程参考。     

基于集料裹浆厚度的水泥基透水砖配合比设计

基于透水砖的结构特征与设计要求,确定了以集料裹浆厚度为主要设计参数,通过改变集料裹浆厚度来满足强度要求的配合比设计思路,提出了一种水泥基透水砖配合比设计方法.该方法首先根据集料紧密堆积密度确定单位体积透水砖中集料的用量,然后根据集料的表观密度和粒径计算集料的比表面积,设定集料裹浆厚度与水灰比(质量比),再计算出水泥浆体体积与水泥用量,最后用减水剂来调整透水砖拌和物的工作状态.试验表明,该透水砖配合比设计方法切实可行.     

建筑尺度合理控制的相关问题浅析

尺度是建筑所特有的艺术法则,也是建筑设计中最基本的问题。本文首先明确建筑尺度的概念及合理控制尺度的重要性,然后探讨在建筑设计中把握尺度的基本原则,最后以高层建筑的外部尺度设计为例,进一步阐述有关建筑尺度的问题。     

一种具有小尺度公平的无线分组调度算法

本文在调度判决时考虑到用户的访问时延限制,比例公平调度算法基础上提出了M-PF算法。本文建立了无线分组调度系统模型,通过仿真对新算法在小尺度服务时间保证、大尺度服务时间公平和系统吞吐量等方面的性能进行分析,研究了系统参数对算法性能的影响。结果证明,新算法在保证系统吞吐量和大尺度公平性的同时可以提供更好的小尺度服务时间保证。