Results 31 to 40 of about 14,388 (188)
从中华鲟( Acipenser sinensis )生活史剖析其物种保护:困境与突围
, 2020 国家一级保护动物中华鲟(Acipenser sinensis)自然繁殖已连续中断3年(2017—2019年)，自然种群濒临灭绝.本文归纳了中华鲟生活史各阶段的生态需求，指出：葛洲坝阻隔是导致中华鲟自然种群衰退的根本原因，三峡等长江上游特大型梯级水电工程的相继蓄水运行是导致中华鲟自然繁殖中断的关键因素，河道冲刷、航道疏浚与挖沙、防洪及城市景观工程等人类活动使中华鲟仔稚鱼栖息地丧失，进而导致补充群体减少，造成繁殖群体持续萎缩.近40年来 ...
危起伟, Wei Qiwei
semanticscholar +1 more source
Rare Metals, EarlyView.ABSTRACT Fluxgate sensors with Co‐rich amorphous microwires, widely used for their low noise in magnetic field measurements, encounter significant challenges in high‐temperature environments such as well drilling and geological exploration. Prolonged thermal aging degrades the performance of Co‐rich amorphous microwires, resulting in increased noise ...
Lining Pan +10 more
wiley +1 more source
Shuitu Baochi Xuebao, 2003 对北碚观音峡背斜岩溶低山不同土地利用方式下土壤的持水、供水、吸水和蒸发特征进行了研究。结果表明,土地利用方式的不同使低吸力段水分状况存在明显差异,样地1,7的供水性能较好,样地3和6持、供水能力都较好,样地9的持、供水性能差,样地4,10的持水性能较好但供水能力较差。样地2,3,5,9土壤比水容量达10-7数量级(ml/Pa·g)时在土水势-10～-30kPa范围开始出现,表明其土壤的保水供水性能相对弱;各样地土壤在土水势-30～-60kPa时比水容量达10-7数量级,表明岩溶山地土壤在脱水过程中 ...
李阳兵 高明 魏朝富 谢德体 刘国一
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Rare Metals, EarlyView.ABSTRACT The limited osteogenic capacity of magnesium phosphate cement (MPC) has constrained its biomedical applications, underscoring the necessity to develop MPC with enhanced physical properties and bone‐forming capabilities. In this study, a multifunctional MPC system was developed by incorporating zoledronic acid‐loaded near‐infrared (NIR ...
Bin Wang +8 more
wiley +1 more source
Dynamics model in the system of Tessaratoma papillosa-parasitoid wasp and its application [PDF]
, 2001 研究荔枝蝽 -寄生蜂系统的数量变动规律 ,得到一个差分 -积分方程组及求解的递推公式 ,指出了公式中参数的确定方法。推导出荔枝蝽 -寄生蜂系统长期演变的特性 ,用模型证明了人工放蜂防治荔枝蝽的优越性及滥用农药的不良后果 ,给出了人工放蜂的最佳次数 ,最佳时刻及合适的放蜂量的计算公式 ,导出的结论与实验结果相符It is well known that Anastatus sp. and Ooencyrtus sp.
李时银, 罗大民
core
Correlation between soil-water characteristic curve and collapsibility in undisturbed loess [PDF]
This study investigates the correlation between the soil-water characteristic curve (SWCC) of undisturbed loess and its collapsibility. Undisturbed loess soil samples, obtained from depths up to 30 meters below the surface in Chang’an District, Xi’an ...
Haiman WANG +3 more
core +1 more source
Rare Metals, EarlyView.ABSTRACT Harnessing solar energy for self‐heating presents an effective strategy to suppress surface ice formation. In this paper, we fabricated nano‐silver‐modified multilayer graphene sheets (Ag@MGs) that integrate photothermal and superhydrophobic properties for anti‐icing applications.
Yihan Zhang +7 more
wiley +1 more source
Shuitu Baochi Xuebao, 2005 通过对金沙江干热河谷新银合欢人工林内枯落物层持水特性的试验研究,总结出林内枯落物层的持水特性。结果表明,新银合欢林内枯落物全年凋落总量为7.03 t/hm2,月平均为0.59 t/hm2,枯落物层的厚度为2.14.5cm,其中12月凋落最盛。枯落物的自然含水量月平均为25.27%,最大月出现在8月,与该区域的降水有较好的拟合关系,但存在滞后效应。持水速率在0.5 h内迅速增大,在浸泡48 h后基本达到最大值,在0.5 h内林内枯落物可以吸收1.2 mm的降水,当降水<11.72 ...
方海东 纪中华 杨艳鲜 拜得珍 廖承飞
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Experiment and modeling of soil-water characteristic curve of unsaturated residual soil [PDF]
, 2014 土-水特征曲线是指基质吸力与含水率或饱和度的关系曲线。土-水特征及其相关数学模型可用于非饱和土性质如渗透系数和抗剪强度模型的建立。通常,土-水特征曲线仅有脱湿曲线。笔者详细讨论了初始含水率、干密度、竖向应力及干湿循环对脱湿曲线的影响。采用滤纸法测试了厦门地区残积土的土-水特征曲线(SWCC)及滞回环。结果表明,初始含水率对SWCC影响较小,最优含水率干侧试样SWCC的进气值小,滞回环小;湿侧试样的进气值大,滞回环大;最优含水率试样的滞回环居中。初始干密度对SWCC有显著影响,低干密度试样SWCC进气值小,
陈东霞, 龚晓南
core
Distribution, scale, and drivers of mass mortality events in Europe's freshwater bivalves
Conservation Biology, EarlyView.Abstract Mass mortality events (MMEs) are decimating populations and compromising key ecosystem functions around the globe. One taxon particularly vulnerable to MMEs is freshwater bivalve mollusks. This group has important ecosystem engineering capacities and includes highly threatened and highly invasive taxa.
Daniel A. Cossey +39 more
wiley +1 more source