Results 31 to 40 of about 11,930 (163)

The Concentration and Carbon Isotope Characteristics of Dissolved Inorganic Carbon in Jiulong River Tributaries and Estuary [PDF]

open access: yes, 2015
碳是重要的生源要素,以各种形态贯穿生命全过程;碳循环是生态系统最重要的物质循环之一。本研究应用稳定同位素技术,以九龙江干流西溪、北溪和河口区域为研究对象,对西溪、北溪及九龙江河口区进行了一个水文年的季节性采样调查,分析了表层水体中溶解无机碳含量及其碳稳定同位素组成(δ13CDIC)、悬浮颗粒物有机碳氮含量及稳定同位素组成(δ13CPOC、δ15NPON),并结合其它相关的水体理化参数对九龙江干流至河口区水体溶解无机碳和颗粒有机碳及其碳稳定同位素的时空变化规律及环境控制因素进行了初步探讨,得出以下结论 ...
梁翠翠
core  

Spatially Downscaling of Future Food Demand for Policy Planning

open access: yesWorld Food Policy, Volume 12, Issue 1, May 2026.
ABSTRACT Understanding the subnational dynamics of food demand, while accounting for the evolution of the agrifood system at the global level, remains a challenge for designing food policy to ensure food security. To link global agrifood systems with subnational food policy planning, we downscale per capita food demand for 62 food commodities at the ...
Chun Song   +3 more
wiley   +1 more source

Submarine groundwater discharge in a subtropical bay and island traced by radium isotopes - Sansha bay and Dongshan island, Fujian [PDF]

open access: yes, 2016
镭同位素来自母体钍的衰变,钍是强颗粒活性的元素,而其子体镭同位素却有一定的水溶性。223Ra、224Ra、226Ra、228Ra的半衰期分别为11.4天、3.6天、1600年和5.75年,这四种同位素的半衰期差异为近岸海域的水团混合和物质交换提供了重要的方法(Moore,1998)。其中,短半衰期的两种同位素能有效地示踪几天至几十天时间尺度的海洋学过程,而在这时间尺度内,长半衰期镭同位素的自身衰变可以忽略(Moore,1998;Moore,2000)。海底地下水排泄(SGD ...
陈利文
core  

Internal physiological drivers of leaf development in trees: Understanding the relationship between non‐structural carbohydrates and leaf phenology

open access: yesFunctional Ecology, Volume 40, Issue 5, Page 1151-1164, May 2026.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Plant phenology is crucial for understanding plant growth and climate feedback. It affects canopy structure, surface albedo, and carbon and water fluxes. While the influence of environmental factors on phenology is well‐documented, the role of plant intrinsic factors ...
Yunpeng Luo   +8 more
wiley   +1 more source

不同植被类型沙地表层土壤水分变化特征

open access: yesShuitu Baochi Xuebao, 2007
通过对沙坡头地区不同植被类型沙地土壤表层水分时空变化特征的研究表明,该区不同植被类型沙地土壤表层水分的分布均符合正态分布,降雨使表层土壤水分的空间变异性减小,空间自相关性减弱,分维数减小,空间自相关范围由干旱时的5m左右内变化扩大到几十米,土壤表层水分的空间依赖性增强;在土壤表层水分含量极低的情况下,土壤表层水分的空间变异性规律与土壤水分含量的变化规律一致;在土壤水分含量不是很低的情况下,其空间变异性与土壤表层水分含量变化趋势相反,流沙地、柠条地A、柠条地B、油蒿地 ...
潘颜霞   +3 more
doaj  

Microeukaryotic community structure and diversity in Xiamen offshore waters and Shenhu Bay, Fujian [PDF]

open access: yes, 2015
微型真核浮游生物是海洋生态系统的重要组成成分,同时在海洋经典食物链和微食物网中发挥重要作用。该类群个体较小,对环境变化较为敏感,作为生产者、消费者和分解者的微型真核浮游生物在海洋生态系统的生物地球化学过程和生态健康评价等方面有着重要意义。本研究选择厦门岛近海海域和福建省泉州市深沪湾为例,对目标海区进行微型真核浮游生物样品的釆集,运用变性梯度凝胶电泳(DGGE)、克隆测序和高通量测序技术方法对微型真核浮游生物群落组成和多样性进行研究,分析其时空分布和群落结构特征 ...
于凌宇
core  

Narrative formatting, chronotopic orderings, and moralization in ex‐gay stories

open access: yesJournal of Linguistic Anthropology, Volume 36, Issue 1, May 2026.
Abstract Formatted stories rely on spatiotemporal cues to evoke recognizability through linearity, which prescribes a particular template for meaning‐making. This article examines stories narrated by ex‐gay members of a Christian organization in Singapore and considers how chronotopes within the stories are ordered to regiment ways of feeling for ...
Vincent Pak
wiley   +1 more source

浑善达克沙地地区土地沙漠化初步研究

open access: yesShuitu Baochi Xuebao, 2004
通过野外调查和对2000年TM影像的解译,分析了研究区土地沙漠化的分布格局与发展态势,以及土地沙漠化造成的负面影响。从气候因子的时空分布与变化和人地关系两大方面,探讨了研究区土地沙漠化发生、发展的原因。结果表明,沙漠化土地在空间分布上,与春季风蚀气候因子分布范围不一致;沙漠化在发展的速率上,与三大气候因子的动态变化不一致。结论指出:近50年来,气候因子的时空变化不是研究区土地沙漠化的主要原因;人畜压力与环境容量严重失衡,研究区人地关系的管理上屡有失误,落后的生产、生活方式转变缓慢 ...
刘树林 王涛
doaj   +2 more sources

FVCOM-based Numerical Simulation of Storm Surge in the Xiamen Bay [PDF]

open access: yes, 2015
中国沿海的风暴潮灾害位于所有海洋灾害之首,每年风暴潮灾害都会造成重大的经济损失和人员伤亡。因此,开展风暴潮的模拟研究是非常必要的。本文选取风暴潮灾害多发的台湾海峡作为研究区域,重点研究台湾海峡西岸的厦门湾的风暴潮变化过程。 本研究基于FVCOM和SWAN建立了台湾海峡-厦门湾海域的潮汐-风暴潮-波浪耦合模型。首先基于厦门湾潮汐潮流模型对厦门湾三维潮汐潮流进行研究,与厦门湾实测资料对比并分析了厦门湾的潮汐潮流性质。研究结果表明:厦门湾潮波主要由台湾海峡经金门岛两侧水道进入湾内 ...
陶小琴
core  

Application‐Grade TiAl Single Crystal With Excellent Room‐Temperature Plasticity and Strength Prepared by Seeded Electromagnetic Confinement Directional Solidification

open access: yesRare Metals, Volume 45, Issue 4, April 2026.
ABSTRACT In this study, a newly developed seeded electromagnetic confinement directional solidification (EMCDS) technique was employed to fabricate large‐scale TiAl single crystal ingots with a diameter of 32 mm, overcoming the long‐standing size limitations that have hindered their industrial application.
Wei Wang   +9 more
wiley   +1 more source

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