Results 31 to 40 of about 26,958 (133)
Shuitu 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 ...
王 +4 more
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Effects of restoration practices on biodiversity in temperate and boreal forests
Conservation Biology, EarlyView.Abstract Several restoration practices are used to mitigate and compensate for the negative effects of large‐scale forestry on biodiversity in temperate and boreal forests. A comprehensive synthesis of the benefits of these practices across taxa is missing. We conducted a systematic review and meta‐analysis on this topic.
Malin Tälle +2 more
wiley +1 more source
TEG血栓弹力图同常规凝血试验的关系及TEG血小板图试验的临床应用
Zhongguo shiyan zhenduanxue, 2012 目的探讨TEG血栓弹力图试验同常规凝血试验的关系,并回顾分析TEG血小板图试验监测抗PLTs药物的临床效果。方法①100例患者,每位分别同时抽取静脉血,做TEG血栓弹力图、常规凝血（aPTT、PT、TT、Fbg）和血常规检测。采用线性相关与回归、多元线性回归与偏回归,评估各参数间关系。②对TEG血小板图试验监测抗PLTs药物的疗效进行回顾性分析。③着重分析MA与PLTs数量的关系。结果 ①MA和CI值均分别与Fbg、PLTs和aPTT,R与aPTT、PT和TT,A与PLTs、aPTT ...
谭延国, 张岩, 王芳, 孙莉
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Gaoya dianqi, 2022 合理控制高压断路器的关合和开断时刻可以在一定程度上降低系统中的暂态过程，选相关合和开断一直是高压断路器在工程应用中的关注点。文中通过等效电路建立了高压交流断路器不同期短路关合过程计算的数值分析模型，可以计算得到任意时刻的全电流、断口电压、交流分量电流和直流分量电流。通过验算国家标准GB/T 30846—2014第4.102规定的短路关合峰值系数验证了计算模型的正确性，并计算了中性点有效接地系统不同期短路关合的峰值系数。最后，应用两个算例分析与讨论了中性点有效接地系统和非有效接地系统中断路器的选相关合技术，
李志新, 吴限, 苑婷, 毛武平
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Assessing and strengthening community‐based coastal governance
Conservation Biology, EarlyView.Abstract Community‐based coastal governance is essential for biodiversity conservation and sustainable livelihoods, yet many communities continue to face significant challenges in establishing and sustaining effective governance systems. We sought to improve understanding of the current status of community‐based coastal governance across five countries
Mark Andrachuk +21 more
wiley +1 more source
Modeling seed germination data to meet biodiversity conservation needs in the Mediterranean
Conservation Biology, EarlyView.Workflow to assess the availability and quality of germination data and assign species' thermal risk in the Mediterranean. (a) Assessment of data availability, including the phylogenetic distribution of the number of records (i.e. available germination data); (b) data quality assessment; and (c) assignment of climate risk categories for species that ...
Diana María Cruz‐Tejada +2 more
wiley +1 more source
Gaoya dianqi, 2009 为了更准确地对超高压线路进行防雷评价和计算,笔者依据长间隙放电与雷击放电的相似性,在实验室中建立击距系数模型,研究击距系数与相关因素的关系。实验结果显示击距系数与雷电流幅值大小并无相关性,但随着线路高度的增加而减小,运用数学分析方法得到击距系数K与杆塔高度h之间满足关系式:K=1.032 3-0.004 1×h。试验结果成功地解释了500 kV天广线某些地段现场屏蔽失效的问题,可以用于超高压输电线路防雷评价和计算。
许飞 +4 more
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Gaoya 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
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3D-QSAR study for inhibitors of cyclin-dependent kinase 4(细胞周期蛋白依赖性激酶CDK4抑制剂的3D-QSAR研究)
Zhejiang Daxue xuebao. Lixue ban, 2008 采用比较分子场分析法(comparative molecular field analysis，CoMFA)和比较分子相似性指数分析法(comparative similarity indices analysis,CoMSIA),系统研究了57个CDK4酶抑制剂的三维定量结构-活性关系.所建立CoMFA和CoMSIA模型的交叉验证系数q2值分别为0.656和0.811，非交又验证相关系数r2分别为0.954和0.969,都具有较好的预测能力 ...
YANGShu-mei(杨书梅) +2 more
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International 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