Results 31 to 40 of about 13,078 (148)

4种灌木林地根系分布特征及其固持土壤效应的研究

open access: yesShuitu Baochi Xuebao, 2007
研究了石灰岩山区的黄栌、连翘、绣线菊和黄荆4种灌木林地根系分布特征及其固持土壤效应。结果表明:4种灌木林地根系的分布特征存在极显著差异,黄栌林地根系的生物量和长度均最大,各径级根系中直径〈1 mm的根系生物量最大;连翘林地根系的生物量和长度均较小,各径级根系中直径≥5 mm的根系生物量最大;黄荆林地根系的生物量和长度较高,主要分布在0~20 cm土壤层;绣线菊林地根系生物量最小,主要分布在0~20 cm土壤层。4种灌木林地土壤的抗侵蚀性能明显高于荒坡地,且与0~20 cm层根系生物量和根系长度显著相关 ...
杨吉华   +4 more
doaj  

滇南地区普洱茶树根系对土壤优先路径形成的影响

open access: yesShuitu Baochi Xuebao, 2021
为明确滇南地区普洱茶种植下土壤优先路径特征以及根系对其形成的影响,以典型普洱茶产地为研究对象,灌草地为对照,基于染色示踪法与图像处理技术,定量分析普洱茶树根系特征与土壤优先路径的关系,解释根系对优先路径形成的影响。结果表明:(1)茶地和灌草地染色路径宽度随土层深度增加呈不同幅度的下降趋势,茶地优先路径的连通性比灌草地差,优先路径的发育程度小于灌草地;(2)根系主要集中分布在土壤表层,随土层深度增加,根重密度、不同径级根长密度均呈减小趋势,径级≤1 mm的根长密度贡献度最大,达到84.08%;(3 ...
卢华兴   +5 more
doaj  

Theoretical and experimental study on the conoscopic interference of a uniaxial crystal(单轴晶体锥光干涉的理论与实验研究)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2005
根据电磁场的边值关系,导出了不同于菲涅耳公式的晶体界面光振幅的关系,提出了晶体锥光干涉中两相干光的位相差和振幅的计算方法.计算结果用数字图像表示,能够直观地显示出晶体锥光干涉图的特征.对不同取向的铌酸锂晶片进行实验,实验干涉图与理论干涉图的特征完全一致.
ZHANGYi(张艺), SHENWei-min(沈为民)
doaj   +1 more source

A new beef: An analysis of discourse coalitions in the nascent cellular agriculture policy subsystem

open access: yesReview of Policy Research, Volume 42, Issue 6, Page 1404-1427, November 2025.
Abstract A robust approach to examining the nature and influence of coalitions in the policy process is the Advocacy Coalition Framework (ACF), which is especially useful to study policy issues fraught with scientific and technical controversy. Yet, important gaps exist in ACF literature regarding nascent policy subsystems. Consequently, there is scant
Nikki Nadeau, Ramiro Berardo
wiley   +1 more source

金沙江干热河谷活跃和稳定冲沟集水区土壤优先流特征

open access: yesShuitu Baochi Xuebao, 2022
为揭示金沙江干热河谷冲沟集水区土壤优先流特征,以金沙江元谋干热河谷地区不同发育程度冲沟(活跃期、稳定期)集水区为研究对象,采用野外染色示踪和统计分析相结合的方法,通过图像处理技术,从野外染色图像中整合出相关5个优先流特征指标,并结合根系特征,对比分析土壤优先流差异规律。结果表明:(1)稳定期冲沟集水区在0—15 cm土层深度范围出现大面积的团块状染色,随后呈小枝状分布,染色区分布相对更加集中,活跃期染色呈整体状—团块状—枝状分布,表明活跃期冲沟集水区染色形态特征更加分化。(2 ...
李志成   +4 more
doaj  

Reproductive outcome after frozen embryo transfer with hormone replacement therapy according to luteal‐phase support protocol: systematic review and network meta‐analysis of randomized controlled trials

open access: yesUltrasound in Obstetrics &Gynecology, Volume 66, Issue 4, Page 422-432, October 2025.
ABSTRACT Objective To compare reproductive outcome between luteal‐phase support (LPS) protocols for frozen embryo transfer (FET) cycles with hormone replacement therapy (HRT). Methods A search was conducted in MEDLINE, Scopus, LILACS, EMBASE, Scielo.br, PROSPERO, CINAHL, PsycINFO, AMED, ClinicalTrials.gov, ICTRP, the Cochrane Library and conference ...
A. Etrusco   +11 more
wiley   +1 more source

基于EOF方法的江西电网雷电时空分布特征分析

open access: yesDianci bileiqi, 2015
根据江西省雷电定位系统2012年至2014年的LLS监测数据,采用经验正交分解方法,分析研究了江西省雷电时空分布特点,得出主要的空间特征向量及其对应的时间系数。结果表明,近3a夏半年雷电活动的空间分布特征以经向型为主,南部及山区雷电活动频繁。对空间特征向量所对应的时间系数的分析发现,江西近3a夏半年雷电活动总体呈增长趋势,时间系数间存在较强的相似特征,表明区域雷电活动具有一定的时空延续性。
童军心   +5 more
doaj  

Strategies in Ericaceae to acquire phosphorus in phosphorus‐impoverished habitats in the southwest Australian biodiversity hotspot

open access: yesFunctional Ecology, Volume 39, Issue 10, Page 2889-2904, October 2025.
Read the free Plain Language Summary for this article on the Journal blog. Abstract In the Southwest Australian Biodiversity Hotspot, the greatest plant species diversity tends to occur on the most phosphorus (P)‐impoverished soils. Many plant species in this P‐impoverished environment release root carboxylates that mobilise soil P which is a more ...
Xue Meng Zhou   +5 more
wiley   +1 more source

Nerd Harder: A Typology of Techno‐Legal Solutionist Logics in Child Online Safety Laws

open access: yesPolicy &Internet, Volume 17, Issue 3, September 2025.
ABSTRACT As jurisdictions worldwide grapple with regulating social media's effects on youth, US state legislatures have emerged as important laboratories for “techno‐legal solutionism”—the belief that complex social problems can be solved through legally mandated technical fixes.
Amanda Reid, Lorcan Neill, Evan Ringel
wiley   +1 more source

Uncovering the Nanozostera japonica species complex suggests cryptic speciation and underestimated seagrass diversity

open access: yesNew Phytologist, Volume 247, Issue 5, Page 2086-2097, September 2025.
Summary The importance of marine angiosperms, or seagrasses, as foundation species for marine coastal ecosystems is in marked contrast to their low species number of only 70 described taxa. Seagrass species tend to have very similar overall morphologies dictated by hydrodynamic forces of the ocean environment.
Xiaomei Zhang   +14 more
wiley   +1 more source

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