Results 31 to 40 of about 1,445 (211)

中国区域地磁场垂直分量日变化特征分析与研究

open access: yesDizhen xuebao
基于我国地磁台站的观测数据,首先根据地磁台垂直分量日变化曲线的形态特征,统计了15个地磁台站垂直分量的极小时间(地方时),并重点探讨了这些极小时间在我国区域内的分布特性及其与台站经度的关系。其次选取27个地磁台垂直分量太阳活动高年与太阳活动低年年均值日变幅,分析垂直分量日变幅与太阳黑子活动之间的关系,并按照劳埃德季节划分的分点月份,夏至点月份、冬至点月份等不同季节及太阳活动高低年分别探讨垂直分量日变幅在不同季节和太阳活动高低年的变化规律及特性。研究结果表明:① ...
Xiuling Zhang, Xudong Zhao, Xiaoyong Fan
doaj   +1 more source

Facilitating Large‐Scale Bird Biodiversity Data Collection in Citizen Science: ‘Relaxed’ Point Counts for Anytime, Anywhere Monitoring

open access: yesEcology and Evolution, Volume 15, Issue 10, October 2025.
This paper proposes a ‘relaxed’ point‐count survey method to enhance accessibility and expand geographic coverage by easing these constraints. Surveys can be conducted in diverse locations, including urban areas and travel routes, within flexible timeframes (e.g., 6 h after sunrise or during the evening) and with adaptable spacing between survey points,
Masumi Hisano
wiley   +1 more source

西沙珊瑚鍶溫度計: 便捷高精度海洋古水溫代用指標 [PDF]

open access: yes, 2001
Strontium concentrations in modem Porites coral from XishaIslands were determined by precise thermal ionization mass spectrometry. The coral skeleton grew in the period from 1976 to 1994.
Lee, T, Nie, BF, Sun, M, Sun, Y
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Spatial Phylogenetic Analysis of Chinese Lizards: Insights Into Ecological Drivers and Conservation Gaps 中国蜥蜴系统发育的空间分析:生态驱动因素与保护空缺

open access: yesIntegrative Conservation, Volume 4, Issue 3, Page 430-441, September 2025.
Our study identifies southern China, including mountainous regions and islands, as key areas rich in phylogenetic diversity, and phylogenetic endemism of lizards that are currently under‐protected. Current protected areas however do not adequately cover regions that are critical for preserving the evolutionary history of lizards.
Tao Liang (梁涛)   +8 more
wiley   +1 more source

变应性鼻炎血清总IgE水平测定及临床意义

open access: yesZhongguo shiyan zhenduanxue, 2012
目的研究血清总IgE在季节性与常年性变应性鼻炎中的变化,并探讨其临床意义。方法采用酶联免疫法检测62例变应性鼻炎患者和20例健康者血清总IgE水平,并进行相关性分析。结果季节性和常年性变应性鼻炎血清总IgE明显高于健康对照组 ...
张茂华   +4 more
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不同季节垃圾填埋场周围重金属污染特征及评价 [PDF]

open access: yes, 2018
采集漳州市某生活垃圾填埋场周围冬夏两季的地表水(包括渗滤液)、土壤以及植物样品,分析9种重金属总量的季节性变化.结果表明,冬季地表水中Zn和As,土壤和植物中的Cd和As的含量均大于夏季,而夏季波动性强于冬季;夏季渗滤液中总Hg的含量明显高于冬季,其余变化不明显.地表水重金属含量均低于地表水环境质量Ⅴ类标准限值,渗滤液中所有重金属含量均低于污水排放二级标准限值.土壤中重金属Cd、As和Pb的污染最重,已达到重度污染,冬季的污染明显高于夏季.冬季植物富集能力强于夏季,细叶芒对Cd的富集能力较强 ...
于珍凤   +5 more
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Seasonality of temperature dependence of methane fluxes from natural wetlands

open access: yesFunctional Ecology, Volume 39, Issue 9, Page 2383-2397, September 2025.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Temperature dependence is a crucial parameter in estimating methane (CH4) fluxes from natural wetlands, yet our understanding of this parameter remains inadequate. Seasonal fluctuations in water levels and ecosystem productivity lead to seasonal differences in CH4 ...
Jinshuai Li   +6 more
wiley   +1 more source

小叶锦鸡儿固沙群落土壤微生物生物活性的季节动态

open access: yesShuitu Baochi Xuebao, 2011
为探讨科尔沁沙地小叶锦鸡儿固沙群落土壤微生物生物量和酶活性的季节动态规律,选取6,11,24年生人工群落和天然群落为对象,研究了不同土层深度微生物生物量(C、N、P)和脲酶、蛋白酶、蔗糖酶、磷酸单酯酶、脱氢酶和多酚氧化酶的活性随季节的变化特征。土壤按5层取样:0-10cm,10-20cm,20-30cm,30-40cm,40-50cm。结果表明,6~24年生小叶锦鸡人工固沙群落及天然群落土壤微生物生物量表现出明显的季节性变化,微生物生物量C和N为夏季>秋季>春季;微生物生物量P为夏季>秋季 ...
曹成有   +3 more
doaj  

西双版纳热带植物园蝙蝠物种多样性与季节变化研究

open access: yes野生动物学报, 2021
为探究中国科学院西双版纳热带植物园中蝙蝠物种多样性及季节变化对蝙蝠物种保护的重要意义,本研究自2019年1—12月在热带雨林地区进行定期声学监测实验并结合2017—2019年竖琴网、雾网捕获情况,共记录到5科14属32种蝙蝠。其中狐蝠科4种、蝙蝠科12种、蹄蝠科5种、菊头蝠科11种。研究表明该地区蝙蝠科、菊头蝠科蝙蝠具有最高的物种多样性,菊头蝠科蝙蝠具有最高的活动强度。32种蝙蝠均具有东洋界的分布特点,但仍有部分蝙蝠科和菊头蝠科蝙蝠在古北界青藏区分布,表明该地区生物分布具有从亚热带向热带过渡的趋势 ...
曹慧 1   +4 more
doaj  

Riverine Nitrate Export Response to Hydro-climatic Variability in a Southeast China Coastal Watershed Based on Long-term Historical Data [PDF]

open access: yes, 2015
气候变化对不同的自然地理区域的淡水系统,尤其是人口集中、对水资源高度依赖的近海流域的潜在影响的研究对于制定合理的水资源管理策略至关重要。本篇论文选取中尺度近海流域—九龙江流域,基于1961-2013年近53年的水文-气候与硝酸盐水质数据,评估气候变化对流域水量和水质及通量的影响。研究结果表明,在过去的50年里,九龙江北溪和西溪年径流量没有明显变化趋势,但随年降雨变化,呈自然波动。本研究开发的L-R图解法显示土地变化加强了气候变化对径流动态的影响。上世纪60年代至90年代之间,硝酸盐的浓度增加了30倍 ...
AYU ERVINIA
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