Results 41 to 50 of about 37,682 (204)

太湖五里湖水体悬浮物中水溶性有机质(WSOM)的荧光光谱组分鉴别及其与氮形态的关系

open access: yes, 2018
采用三维荧光光谱-平行因子法(EEMs-PARAFAC)分析太湖五里湖水体悬浮物中水溶性有机质(WSOM)的荧光光谱特征,研究其组分类型、分布规律以及来源,进一步探讨悬浮物中水溶性有机氮和无机氮含量与WSOM荧光组分之间的关系.结果表明,悬浮物中WSOM荧光组分主要由2个类腐殖质(C1、C2)和1个类色氨酸类蛋白质(C3)组成.总荧光强度在57.56~200.01 R.U./g之间,平均为115.42 R.U./g,其中C1、C2、C3的相对比例分别为35.55%、34.05%和30.40 ...
张博   +9 more
semanticscholar   +1 more source

台田措施下坡面流土壤侵蚀水动力学特征

open access: yesShuitu Baochi Xuebao, 2019
通过野外径流小区放水试验,研究2种台田类型(土坎,石坎)、3种台田级数(1,2,3级)、1种坡度(10°)、3种放水流量(0.5,1,1.5 m3/h)下坡面流土壤侵蚀过程,分析台田措施下坡面流土壤侵蚀水动力学特征。结果表明,台田级数对坡面流流态影响较大,增加台田级数可使坡面流波动性降低,台田类型对雷诺数影响相对较小。土壤分离速率总体随流量增大而增大,相同流量条件下,呈波动性增加后减少且逐渐趋于平稳的特征,两者相关关系用指数函数回归方程拟合(R2>0.840)。同类台田且田面宽度和相同条件下 ...
肖丛宇   +6 more
doaj  

Providing regular and frequent maps of losses and gains of farmland birds based on European monitoring data

open access: yesConservation Biology, EarlyView.
Abstract Knowledge of species distributions is essential for informing policies on nature conservation and restoration. However, updating them on a regular basis and doing so in a harmonized manner at the international level is difficult. The European Bird Census Council integrated national monitoring data covering 5 years to update farmland bird ...
Sergi Herrando   +54 more
wiley   +1 more source

The application of Benford's law to groud lightning data(Benford定理在地闪数据中的应用)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2014
自然界数据库中的首位非零1~9数字并不等概率出现,其出现概率符合对数分布,即Benford定理.概述了 Benford定理及其适用范围,在研究浙江省闪电定位系统的2007~2012年监测数据时,发现正闪和负闪的每日地闪频次的首位数字占比情况非常符合Benford定理(相关系数分别为0. 995 6和0. 997 9).正闪雷电流幅值的首位数字占比情况与Benford定理相当吻合(相关系数为0.997 9),但负闪雷电流幅值的首位数字占比却与定理的相关性较差(相关系数为0.
FENGZhiwei(冯志伟)   +4 more
doaj   +1 more source

The study of the Influence of Shanghai-Hong Kong Stock Connect Program on the Shanghai Stock Market [PDF]

open access: yes, 2016
为了改善股票市场环境、完善市场制度,近年来国家不断深化资本市场的开放,陆续推出了QFII、QDII、RQFII等制度,推进资本的双向流动。在这个开放的过程中,2014年11月17日开通的沪港通,第一次实现了境内外股票市场的互通互联,实现了在境内外资本在个股层面的双向流动,加快了境内市场对外开放的步伐,是我国资本市场开放进程中的一个里程碑事件。 本文采用自下而上的思路,从三个层面来对沪港通展开研究。首先从标的股票交易层面,分析沪港通开通对标的股票价格和波动性的影响;其次,从股票市场指数层面 ...
黄文
core  

Emerging applications of large language models in ecology and conservation science

open access: yesConservation Biology, EarlyView.
Abstract Large language models (LLMs) mark a major development in artificial intelligence, with potentially transformative implications for ecology and conservation science. Built on advanced deep‐learning architectures, these models can support a wide range of tasks. We reviewed emerging applications of LLMs, drawing on the wider scientific literature
Christos Mammides   +5 more
wiley   +1 more source

换流变压器铁心饱和型谐波不稳定分析

open access: yesGaoya dianqi, 2021
介绍了高压直流输电系统中2次谐波的传递过程,以及由此可能引发的谐波不稳定性。针对变压器绕组中存在的直流电流而导致的2次谐波电流进行了仿真分析研究,得出了励磁电流中2次谐波幅值与直流电流的关系。2次谐波幅值与直流电流的关系由线性系数X体现,从换流变压器阀侧看入交流系统侧的阻抗与变压器变比N以及线性系数X相关,相关系数为(1/N-3/2X),线性系数X与变压器的额定励磁电流Im呈负相关。结果表明 ...
刘洪涛   +7 more
doaj  

Insights for conservation from the Ecological Knowledge Games project

open access: yesConservation Biology, EarlyView.
Abstract Environmental conservation research requires robust methods for collecting large‐scale behavioral data and engaging diverse stakeholders in decision‐making processes. We (Y.P., A.B.D., and N.B.) created EcoKnowGames (Ecological Knowledge Games), a transdisciplinary project that develops knowledge games for conservation science and data ...
Yuan Pan   +4 more
wiley   +1 more source

胶东半岛丘陵区冲沟分形特征及其影响因素研究

open access: yesShuitu Baochi Xuebao, 2016
以胶东半岛丘陵区7个集水区为研究对象,采用SA模型提取研究区冲沟系统,测算冲沟沟长盒维数,分析沟长分形特征及其与地形参数和土地利用类型间的关系,厘定研究区内冲沟发育演化的特征及规律。结果表明:(1) 东部构造活动性强的隆起区分维值明显高于西部构造活动性弱的沉积凹陷区沉降区,沟长分形特征主要受区域地质构造控制。(2) 沟长分维数与平均坡度、地表粗糙度、剖面曲率、沟壑密度和沟头密度等地形参数之间相关性显著,而与集水区面积和沟长没有相关性。(3) 沟头密度、沟壑密度与沟长分维数间具有极显著正相关性 ...
  +4 more
doaj  

Artificial Intelligence for Language Learning: A Systematic Review of its Design, Theoretical Foundations, Implementation, and Impact

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT Although the use of AI technologies (e.g., chatbots and automated writing evaluations (AWE)) has gained considerable attention in language learning fields in recent years, how AI technologies have been designed and implemented in language learning education, as well as their effectiveness, is understudied.
Shen Qiao   +2 more
wiley   +1 more source

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