Results 51 to 60 of about 1,355,674 (190)
, 1989 本文先用Ljapunov泛函方法求解在具有任意状态方程的流体介质中传播的一维平面定常激波在一维小扰动下的运动学稳定性问题。 得出激波的运动学稳定条件为—l≤i~2(dv/dp)_H≤1,其中—不i~2是激波Rayleigh线的斜率,(dv/dp)_H是Hugoniot线斜率。此条件与过去从唯象方法得到的条件一致,然后通过对这一条件能量意义的分析,提出一般的激波一维稳定性的能量原理,并由此得出激波能量稳定条件是—1≤i~2(dv/dp)_H≤l—p_o/p_l, 其中P_O、p_l分别是波前、波后压力 ...
黄迎雷, 崔季平
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四川大学学报. 自然科学版, 1994 研究一类具无限时滞的泛函微分方程的可解性和稳定性。其基本结果是：在某些条件下，非线性泛函微分方程解的指数稳定性可由解的有界性及线性部分的指数稳定性推出。
梁进, 肖体俊, 黄发伦
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Unveiling Entropy‐Driven Hard‐Tough Synergy Mechanisms in High‐Entropy Carbonitride Ceramics
Rare Metals, Volume 45, Issue 9, September 2026.ABSTRACT High‐entropy ceramics manifested promise for extreme environments, yet their phase stability and mechanical synergy mechanisms remain elusive. Herein, entropy‐difference carbonitrides, including (TaTiV)CN, (TaTiVNb)CN, and (TaTiVNbHf)CN, were designed and consolidated via spark plasma sintering.
Long Zhao +6 more
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Jianzhu Gangjiegou Jinzhan, 2010 本文采用基于B-R运动准则改进的动力稳定判别方法,结合结构的时程响应曲线,采用有限元软件ANSYS分别研究了El-Centro波、Taft波和天津波作用下不同矢跨比弦支穹顶结构的动力稳定性能和稳定形态,并作了比较。研究表明3种地震作用下,结构失稳形态均是非对称的;无论何种地震波下,结构的矢跨比越大,结构的稳定性越强;对于同一种矢跨比结构,El-Centro波作用下的结构动力稳定临界值最大,结构动力稳定性最好;天津波作用下的结构动力稳定临界值最小,结构动力稳定性最差。由此可见 ...
刘慧娟 +3 more
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World Medical &Health Policy, Volume 18, Issue 3, September 2026.ABSTRACT Confrontational violence still puts catastrophic burdens on children, with 2024 being the highest recorded levels of displacement, malnutrition, injury, and deprivation in contemporary humanitarian history. Children's surgical care is still grossly underrepresented in health responses worldwide in the prevention of avoidable deaths and long ...
Gaurav Chanderprakash Mittal +4 more
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, 1979 星系密度波理论成功地解释了螺旋结构的缠卷困难。为了克服有限群速度引起的维持困难,人们研究了各种线性波的不稳定增长模式解。线性波的不稳定性分析只能适用于短的时间发展,所以应该进一步讨论非线性密度波的稳定性。徐遐生等用星系激波方程计算恒星的非线性密度波时发现,解极敏感地依赖于初值的选择,可能在物理上不稳定 ...
王联, 胡文瑞, 王慕秋, 秦元勋
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Multi‐gradient warming reshapes functional traits and adaptive responses of alpine meadow plants
Functional Ecology, Volume 40, Issue 9, Page 2889-2905, September 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Plant functional traits in alpine meadows are critical indicators of ecosystem responses to climate warming, yet dynamic changes in trait networks across warming gradients and their consequences for community functions remain poorly understood.
Zhiwei Yan +6 more
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, 1985 本文用导数展开法对液体薄层与亚音速气流接壤时的界面稳定性作非线性分析.文中考虑了液体的表面张力与体积力,故非线性的Rayleigh-Taylor不稳定性可作为特例而导出;液体与气体均不计粘性.虽然Nayfeh曾算过这一情况,但其三阶方程有遗漏(如213页的式(2.29)).同时解也不自洽(如其一阶解(2.31)并不满足他的初始条件(2.20)),此外,在截止波数附近,对行波他并未考虑.本文弥补了这些 ...
陈乐山
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Shuitu Baochi Xuebao, 2021 以汉江与嘉陵江源区黄土母质上发育的土壤为研究对象，通过对土壤团聚体和理化性质的试验分析和数据解析，研究了两地土壤团聚体的分布规律及发生机制。结果表明：（1）汉江源区（LJH）团聚体的R0.25、MWD、GMD值由A层的83.73%，2.17和1.11分别降为C层的59.18%，0.40和0.26，嘉陵江源区（YJS）由A层的69.72%，1.03和0.46降为C层的56.55%，0.52和0.27，分形维数（D）则随土层深度的加深而增大，即前者的D值由A层的2.46增为C层的2.53，后者由A层的2 ...
刘艳玲 +5 more
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Phenology drives asymmetric responses of ecosystem productivity stability to warming and cooling
Functional Ecology, Volume 40, Issue 9, Page 2959-2971, September 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Ecosystem productivity stability is a key indicator of ecosystem functioning under climate change, but the role of cooling periods in increasingly variable climates remains poorly resolved.
Yao Wei +11 more
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