Results 31 to 40 of about 1,058,102 (105)

A study of elasticity deformation of polymethylene chain(聚亚甲基链的弹性形变研究)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2001
本文采用旋转异构态模型,对聚亚甲基链受到无相变的弹性形变后的热力学性质进行研究,计算出在不同形变时聚亚甲基链体系的自由能、内能等热力学函数,同时还分析了应力与弹性形变的关系以及内能对弹性形变的贡献.
JIANGZhou-ting(姜舟婷)   +2 more
doaj   +1 more source

The New World Order and National Security Dynamics of African States: Case Studies of Cameroon and Mali

open access: yesWorld Affairs, Volume 189, Issue 4, Winter 2026.
ABSTRACT The move from unipolarity to a fluid and contested multipolar world order has significantly changed the way African nations form national security policy due to changes in the nature of the strategic environment of those states. Much of the literature has focused on how the actions of major world powers ‐ the United States, China and Russia ...
Chick Edmond   +2 more
wiley   +1 more source

基于数据分析的变压器套管新型在线监测预警策略研究

open access: yesGaoya dianqi, 2018
套管是电力变压器的重要附件,其安全稳定运行至关重要。为此,常采用在线监测技术对其运行状态进行实时监测。在电网内部,变压器套管在线监测系统已有一定应用。然而,监测数据不仅取决于套管自身绝缘性能,而且受温度、湿度和系统运行电压等环境因素影响,且当前各套管监测厂家推荐的预警策略各异,难以满足应用要求。因此研究适宜的在线监测预警策略至关重要;文中对广东电网在运变压器套管的介损值历史监测数据进行了统计分析。研究发现变压器套管在线监测应用过程中会出现短时性、间歇性的数据异常,异常率接近1%,导致监测系统告警 ...
夏健   +7 more
doaj  

Poverty, Inequality, and Social Security During the COVID‐19 Pandemic: Evidence From Linked Swiss Tax Data

open access: yesPoverty &Public Policy, Volume 18, Issue 3, September 2026.
ABSTRACT This paper examines the impact of the COVID‐19 pandemic on income and wealth inequality in Switzerland, with a particular focus on poverty dynamics and the role of the social security system. Using newly linked administrative tax data for four large cantons covering over a third of the Swiss population, we track changes in household income and
Oliver Hümbelin   +2 more
wiley   +1 more source

Engineering Stress‐Decoupled SnP2O7@Carbon Core Shell via Spatial Confinement for Cycling‐Stable Sodium Storage

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT Tin‐based composite oxides typically undergo severe volume variations and exhibit poor intrinsic conductivities despite their high theoretical capacity as promising anode candidates for sodium‐ion batteries. This results in rapid structural degradation and capacity fading upon cycling.
Yongmei Sun   +5 more
wiley   +1 more source

模拟降雨条件下坡度与地表糙度对径流产沙的影响

open access: yesShuitu Baochi Xuebao, 2016
通过室内模拟降雨试验,研究坡度与地表糙度对土壤侵蚀的影响。根据研究区坡耕地特点,试验共设计5个坡度,分别为9°,12°,15°,20°,25°,设计雨强为1.0 mm/min,降雨历时为60 min。结果表明:5个坡度下坡面径流总量表现为先增大后减少,在20°与25°坡面表现出显著性差异,地表糙度变异率降幅为12°>9°>25°>15°>20°;(2)次降雨产流量与坡度、糙度变异变率呈显著指数函数关系;(3)5个坡度其坡面产沙量表现为先增大后减少,产沙量在坡面梯度为3°的坡面之间以及20°与25 ...
王 添   +7 more
doaj  

A Green Strategy for the Ultrafast Synthesis of Functional Hydrogels Toward Intelligent Human–Machine Interfaces

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT With the rapid development of flexible electronics, there is an increasing demand for hydrogel‐based sensors with rapid fabrication, robust mechanical performance, and stable sensing behavior. Herein, a green and ultrafast self‐catalytic strategy is developed to fabricate a multifunctional hydrogel based on tannic acid‐coated cellulose ...
Jin Qian   +6 more
wiley   +1 more source

塔中沙漠植物园土壤水盐空间变异性及合理取样数研究

open access: yes, 2010
本研究运用经典统计学和地质统计学方法,分析了塔中沙漠植物园内下层根系土壤水盐的空间变异特性,结果表明:塔中沙漠植物园下层根系的土壤水盐分布具有中等空间变异性,80cm、100cm、120cm、140cm土层土壤水分变异系数分别为44.16%、41.30%、45.53%、55.44%,盐分变异系数为41.51%、34.00%、42.28%、30.52%。各层土壤质量含水量分别满足指数、高斯、指数和线性模型,土壤电导率变异函数的最佳理论模型分别为球状、球状、线性和线性模型 ...
徐新文   +4 more
core  

盐渍化灌区土壤水盐时空变异特征分析及地下水埋深对盐分的影响

open access: yesShuitu Baochi Xuebao, 2019
针对盐渍化灌区土壤盐渍化问题,以河套灌区下游乌拉特灌域为研究区,通过野外实测与室内试验分析结合,采用统计学方法地质统计学原理分析表层土壤(0—20,20—40 cm)及深层土壤(40—100 cm)含水率与盐分(EC值)时空分布和变异规律,以及探求地下水埋深对土壤盐分的影响。结果表明:(1)除6月0—20 cm(9.779%)外,表层土壤含水率变异系数均在12.384%~19.667%,属于中等变异性,深层土壤含水率变异系数较小,在3.513%~9.757%,属于弱变异性)表层土壤盐分(EC值 ...
窦旭   +6 more
doaj  

Toward a New Generation of AI‐Enabled Wearable Sensors

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT Wearable sensors have emerged as important platforms for noninvasive, real‐time, and continuous monitoring of physiological information, with growing applications in personalized healthcare, human‐machine interfaces (HMIs), and robotic empowerment.
Tianqi Yang   +7 more
wiley   +1 more source

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