Results 61 to 70 of about 478,795 (192)

特高压直流线路保护研究现状分析

open access: yesGaoya dianqi, 2018
文中以特高压直流输电线路保护为对象,分析了国内外实际工程应用中继电保护技术和原理存在的问题。行波保护作为现有特高压直流线路的主保护优势明显,但存在耐过渡电阻能力有限、对采样频率要求高等问题。微分欠压保护作为行波保护的冗余保护,缺点类似行波保护,同时缺乏整定依据等。低电压保护在耐过渡电阻能力方面较强,但其选择性较差,动作速度不够快。电流纵差保护选择性好,但由于受到线路分布电容的影响且动作时间长。文中通过梳理当前特高压直流输电线路继电保护技术进展以及存在的问题,并提出利用边界元件、特征频率 ...
李振兴   +4 more
doaj  

Navigating the Algorithmic State: Public Values and Citizens' Preferences of AI‐Driven Public Service Delivery

open access: yesPublic Administration, EarlyView.
ABSTRACT As the public sector increasingly adopts AI‐powered automated decision systems (ADS), understanding how citizens experience and value ADS use in public decision‐making is both normatively and practically important. Therefore, we examine and compare the effects of seven attributes of public values on citizens' support for ADS adoption in two ...
Guimin Zheng   +4 more
wiley   +1 more source

广东大峡谷自然保护区社区公众野生动物保护意识调查

open access: yes野生动物学报, 2010
2008年6月,对广东大峡谷自然保护区社区公众野生动物保护意识进行了问卷调查。结果表明:(1)公众对野生动物保护知识匮乏,缺乏野生动物保护法制意识;(2)公众普遍对野生动物面临的威胁有较明确的认识,具有保护意愿,但缺乏保护野生动物的积极性和主动性;(3)公众接受野生动物保护教育的主要途径是电视。本文针对广东大峡谷自然保护区公众野生动物保护意识现状及其存在的问题,提出了一些建议。
潘岽生   +5 more
doaj  

Algorithmic Literacy and Quotidian Curation Practices: Rethinking User Agency in the Social Media Regulation Era

open access: yesPolicy &Internet, Volume 18, Issue 4, December 2026.
ABSTRACT This paper examines the practices ordinary social media users employ to influence the content served to them by platform algorithms, and the relationship between these practices and levels of algorithmic literacy. Practices were documented across TikTok, Facebook, Instagram, Twitter (now X), YouTube and Reddit during 65 sessions, conducted as ...
Agata Stepnik, Joanne Gray
wiley   +1 more source

Comparison of different teaching models on career adaptability of clinical nursing students (“2+2”教学模式与普通教学模式对实习护生生涯适应力影响的比较研究)

open access: yes中西医结合护理
Objective To investigate the career adaptability of clinical nursing students who received the 2+2 teaching model compared with those received general teaching model, and to discuss the correlation between different teaching models and the level of ...
TIAN Ying (田颖)   +4 more
doaj   +1 more source

Environmental Justice in the Brazilian Coastal Food Systems: Policies, Institutions, and Knowledges on Small‐Scale Fishers and Energy Development

open access: yesWorld Food Policy, Volume 12, Issue 2, November 2026.
ABSTRACT This study explores environmental justice issues in coastal food systems, focusing on conflicts between small‐scale fisheries and the energy sector due to differing goals in managing food and energy sources. It does so by examining the interdependence between institutions, policies, and different types of knowledge; key elements in building ...
Mateus Henrique Amaral   +6 more
wiley   +1 more source

桂平博物馆馆藏东汉双耳铜甑铸造工艺及其保护修复研究

open access: yes, 2018
广西桂平博物馆藏东汉铜甑对于研究广西地区青铜器冶铸技术的发展具有重要的研究价值。但器物长期保存于潮湿环境中,矿化严重、保存状况较差,亟须保护修复。本研究应用X射线影像观察、金相显微镜、扫描电镜及能谱分析、模拟实验验证等方法研究了器物的铸造工艺、合金成分以及锈蚀产物成分。结果表明该器物为整体铸造成形,器物铸造时使用了轮制技术、刮板造型工艺以及铸后刻纹的工艺,箅部范块制作过程是用器身模翻制器身范后脱模,将器身模的圈足部分切下,然后在圈足泥模上刻出箅部型腔。在此基础上,遵循最低限度干预原则 ...
黄献源   +5 more
core   +1 more source

第二批国家级自然保护区公布

open access: yes野生动物学报, 1988
国务院最近向各省、自治省、直辖市人民政府和国务院各部委、各直属机构发出通知,公布了第二批国家级森林和野生动物类型自然保护区名单如下:雾灵山自然保护区(河北省);历山自然保护区(山西省);大青沟自然保护区(内蒙古自治区);白石砬子自然保护区(辽宁省);双台河口自然保护区(辽宁省);丰林自然保护区(黑龙江省);呼中自然保护区(黑龙江省);古牛绛自然保护区(安徽省);梅花山自然保护区(福建省 ...
doaj  

弹性分组环中一种新型保护倒换机制

open access: yesGuangtongxin yanjiu, 2007
针对弹性分组环(Resilient Packet Ring,RPR)技术中的源路由和环回两种保护倒换机制的不足,文章提出了一种新型保护倒换机制———源节点保护倒换,并对这种保护倒换机制的性能进行了分析。源节点保护倒换克服了源路由保护倒换存在的严重的丢包现象,避免了包失序问题,同时减小了环回保护倒换产生的较大时延和不必要的带宽浪费,充分提高了RPR中保护倒换的性能。
赵永利, 曹淼, 张杰, 顾畹仪
doaj  

Addressing the Right to Food Through Food Expenditure Burdens: Distributional Evidence Among Low‐Income Farming Families in Brazil (2012–2023)

open access: yesWorld Food Policy, Volume 12, Issue 2, November 2026.
ABSTRACT Household food expenditure continues to be a key factor in ensuring the realization of the Human Right to Adequate Food. Particularly in Brazil, access to food can be limited by economic constraints in vulnerable families, especially among farming families, who have been more vulnerable to food insecurity in recent years in the country.
Lucas de Almeida Moura   +3 more
wiley   +1 more source

Home - About - Disclaimer - Privacy