Results 11 to 20 of about 1,282,396 (139)
Abstract Invasive species can dramatically alter ecosystems, but eradication is difficult, and suppression is expensive once they are established. Uncertainties in the potential for expansion and impacts by an invader can lead to delayed and inadequate suppression, allowing for establishment.
Brian D. Healy +5 more
wiley +1 more source
Abstract As agricultural land use and climate change continue to pose increasing threats to biodiversity in sub‐Saharan Africa, efforts are being made to identify areas where trade‐offs between future agricultural development and terrestrial biodiversity conservation are expected to be greatest. However, little research so far has focused on freshwater
Cody Danaher +3 more
wiley +1 more source
针对废水生物处理中导流筒直径、表观气速、液位高度、黏度和表面张力对气升式反应器内流场和氧传质系数的影响进行研究,并利用气水冷模实验对气升式反应器进行简化分析。随着导流筒直径的增加,气含率、液速和氧传质系数都增大,最佳导流筒直径为120 mm。表观气速存在一个临界值,低于临界值,气含率、下降段液速和体积氧传质系数等特征参数随气速增加迅速增大;高于临界值特征参数增加变缓,最佳表观气速为3.0×10-3 m/s。随着液位高度的增加,气含率和体积氧传质系数减小,下降段液速增大,最佳液位高度为900 mm ...
吴松, 任慧敏
doaj +2 more sources
A systematic review of 20 years of crisis and disaster research: Trends and progress
Abstract The field of crisis and disaster studies has proliferated over the past two decades. Attention is bound to grow further as the world negotiates the prolonged challenges of the Covid‐19 pandemic. In this review, we provide an overview of the main foci, methods, and research designs employed in the crisis and disaster research fields in the ...
Jeroen Wolbers +2 more
wiley +1 more source
电晕是造成车顶绝缘子老化的主要因素之一。基于高速气流试验平台,试验研究了高速气流电晕环境下硅橡胶表面的憎水性分布,通过分析高速气流对电晕放电路径和放电电流的影响,讨论了憎水性分布发生偏移的原因。研究发现:高速气流环境下电晕强度较大时,憎水性丧失最严重的部位沿气流方向发生偏移。其原因是:当电晕放电沿针尖发展至针板间隙空间时,高速气流使得电晕放电路径沿气流方向偏转。气流速度一定时,离子所受电场力随电压的增大而增大,高速气流不易将其吹离针板间隙空间 ...
张晓青 +4 more
doaj
高超声速飞行器在飞行过程中,由于黏性耗散和激波压缩,流动一般具有高速、高温和热化学非平衡的特点:同时由于气动热约束,高超声速巡航要求在密度较低的大气环境中进行,稀薄气体效应显现,流动物理更为复杂。本文结合CFD与DSMC方法,分别模拟了平板、圆柱和球头等简单外形在氩气和近真实大气环境中飞行时的流场,分析了稀薄气体效应对高超声速流动的一些影响规律。研究发现,平板前缘存在局部稀薄气体效应 ...
陈松, 孙泉华, 胡远
core +1 more source
对采用聚丙烯中空纤维膜组件运用膜气提法去除水体中甲基叔丁基醚(MTBE)进行了初步研究,着重考察了温度、气体流速、液体流速及气体压力等因素对去除效果的影响。结果表明,膜气提法是一种比较有效地去除水中MTBE的技术,去除率98%左右;温度、气体流速和液体流速对去除率有显著影响:去除率随水温的升高而增大,随气体流速和液体流速的增加而升高;而气体压力对去除率的影响则不明显。
姜斌, 许丽娟, 纪志永
doaj +2 more sources
ABSTRACT Pore engineering reduces the thermal conductivity of thermoelectric materials, yet typically degrades electrical conductivity by enhancing carrier scattering—a long‐standing trade‐off. Here, we overcome this trade‐off in SrTiO3‐based entropy‐engineered ceramics via a one‐step synergistic strategy: using poly(methyl methacrylate) (PMMA) as a ...
Ziyao Wei +7 more
wiley +1 more source
ABSTRACT Photocatalytic hydrogen peroxide (H2O2) production from water and oxygen driven by solar energy represents a highly promising green and sustainable strategy. Herein, lignin‐derived carbon quantum dots (LCDs) were strategically introduced at the heterojunction between a Bi‐based metal organic framework (Bi‐MOF) and ZnIn2S4 (ZIS).
Wanpeng Sun +8 more
wiley +1 more source
ABSTRACT NiCoCrAlYTa coatings are widely used as bond coats in thermal barrier coating (TBC) systems for gas turbines and aeroengines to provide oxidation resistance and support the formation of a protective thermally grown oxide (TGO). Herein, high‐current pulsed electron beam (HCPEB) modification was utilized to strengthen a NiCoCrAlYTa coating by ...
Xiangcheng Li +6 more
wiley +1 more source

