检索结果-南通市图书馆

Spalling characteristics of high-temperature treated granitic rock at different strain rates

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1280-1288页

作者： l.F.Fan q.H.Yang X.l.Du The Key laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing100124China

The dynamic spalling characteristics of rock are important for stability analysis in rock *** paper presented an experimental investigation on the dynamic spalling characteristics of granite with different temperatures and strain rates.A series of dynamic spalling tests with different impact velocities were conducted on thermally treated granite at different *** dynamic spalling strengths of granite with different temperatures and strain rates were determined.A model was proposed to correlate the dynamic spalling strength of granite,high temperature and strain *** results show that the spalling strength of granite decreases with increasing ***,the spalling strength of granite with a higher strain rate is larger than that with a lower strain *** proposed model can describe the relationship among dynamic spalling strength of granite,high temperature and strain rate.

关键词： Dynamic spalling characteristics High temperature Strain rate Dynamic loading Granite

Electron kinetic effects in back-stimulated Raman scattering bursts driven by broadband laser pulses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第4期9卷 54-67页

作者： q.K.liu l.Deng q.Wang X.Zhang F.q.Meng Y.P.Wang Y.q.Gao H.B.Cai S.P.Zhu Graduate School China Academy of Engineering PhysicsBeijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100094China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026China Shanghai Institute of laser Plasma Shanghai 201800China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China School of Physics Zhejiang UniversityHangzhou 310027China

We examine electron kinetic effects in broadband-laser-driven back-stimulated Raman scattering(BSRS)bursts using particle-in-cell *** bursts occur during the nonlinear stage,causing reflectivity spikes and generating large numbers of hot ***-duration simulations are performed to observe burst events,and a simplified model is developed to eliminate the interference of the broadband laser’s random intensity *** the simplified model,we isolate and characterize the spectrum of electron plasma *** spectrum changes from a sideband structure to a turbulence-like structure during the burst.A significant asymmetry in the spectrum is *** asymmetry is amplified and transferred to electron phase space by high-intensity broadband laser pulses,leading to violent vortex-merging and generation of hot *** proportion of hot electrons increases from 6.76%to 14.7%during a single violent burst *** demonstrate that kinetic effects profoundly influence the BSRS evolution driven by broadband lasers.

关键词： scattering kinetic simplified

Precipitation of multi-type nano-quasicrystals in a Mg-Zn-Y alloy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第3期12卷 997-1008页

作者： W.Z.Wang X.Z.Zhou l.F.Zhang H.q.Ye Z.q.Yang Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China Ji Hua laboratory Foshan 528251China Foshan University Foshan 528231China

Mg-6Zn-1Y(at.%)ribbons with strengthening precipitates of multi-type nanoquasicrystals were prepared by melt-spinning followed by aging *** evolution of the rapidly solidified ribbons during isothermal aging was comprehensively studied using various electron microscopy *** new kinds of decagonal quasicrystals were formed in aged ribbons,in addition to precipitation of nanometer icosahedral ***-resolution observations reveal that both decagonal quasicrystals can be modeled by quasiperiodic tiling with decagonal clusters of 2.5 nm in diameter,but overlap of neighboring clusters in both decagonal quasicrystals is different from the Gummelt model observed in other quasicrystals.A shell composed of complex laves Mg-Zn domains was formed surrounding each decagonal quasicrystal precipitate upon prolonged *** addition,all kinds of nanoprecipitates exhibit excellent structure and size stability at 573 *** findings may have implications for not only fundamental studies about quasicrystals,but also microstructural manipulation of high-performance Mg alloys.

关键词： quasicrystal Mg alloys Rapid solidification Scanning-transmission electron microscopy.

In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第5期12卷 1841-1853页

作者： M.lv H.l.Ge q.q.Jin X.H.Shao Y.T.Zhou B.Zhang X.l.Ma Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the *** results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being *** is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous *** latter plays a key role in precipitation *** result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

关键词： Mg alloy Electron beam irradiation Hardening Precipitates In-situ TEM

Weighted Probability Density Estimator with Updated Bandwidths

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第2期37卷 886-906页

作者： WU yi YU Wei WANG Xuejun PRAKASA RAO B l S School of Big Data and Artificial Intelligence Chizhou UniversityChizhou 247000China School of Big Data and Statistics Anhui UniversityHefei 230601China CR Rao Advanced Institute of Mathematics Statistics and Computer ScienceHyderabad 500046India

In this paper,the authors study a class of weighted version of probability density *** is shown that the weighted estimator contains some existing estimators of probability density,no matter they are recursive or *** statistical results including weak consistency,strong consistency,rate of strong consistency,and asymptotic normality are established under some mild ***,the random weighted estimator is also *** numerical simulations and a real data analysis are presented to study the numerical performances of the estimators.

关键词： Asymptotic normality consistency numerical simulation probability density real data analysis updated bandwidths weighted estimator

Improved Reall-Santos method for AdS black holes in general 4-derivative gravities

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 74-86页

作者： Peng-Ju Hu liang Ma Hong lü yi Pang Center for Joint quantum Studies and Department of Physics School of ScienceTianjin UniversityTianjin 300350China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China Peng Huanwu Center for Fundamental Theory Hefei 230026China

For asymptotically flat black holes,Reall-Santos method is a convenient tool to compute leading higher derivative corrections to the thermodynamic quantities without actually solving the modified field ***,there are subtleties in its generalization to asymptotically AdS black holes with general higher derivative *** of all,it is necessary to know all the higher derivative holographic counterterms and the surface terms implementing the variational principle and subtracting the *** then needs to solve for the modified AdS radius and rescale the time coordinate in an appropriate way such that the induced metric on the conformal boundary of AdS black hole is not *** observe that Reall-Santos method can be directly applied to a particular 4-derivative gravity model,known as the Einstein-Weyl gravity,which does not modify the AdS radius and requires only the Gibbons-Hawking-York term and holographic counterterms for the 2-derivative *** thus suggest that to compute the thermodynamic quantities of AdS black holes in general 4-derivative theories of gravity,one simply needs to transform it to a Einstein-Weyl gravity with identical thermodynamic variables by appropriate field *** explicitly verify this proposal with spherically-symmetric and static charged black holes in Einstein-Maxwell theory extended with generic 4-derivative interactions.

关键词： black holes thermodynamics higher-derivative corrections effective theories higher dimensional black holes quantum gravity

A landscape persistence-based methodological framework for assessing ecological stability

在线全文

学校读者我要写书评

暂无评论

Environmental Science and Ecotechnology 2024年第1期17卷 31-39页

作者： Da lü yihe lü Guangyao Gao Siqi Sun yi Wang Bojie Fu State Key laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesPO Box 2871Beijing100085China University of Chinese Academy of Sciences Beijing100049China

Ecological stability is a critical factor in global sustainable development,yet its significance has been *** we introduce a landscape-oriented framework to evaluate ecological stability in the qingzang Plateau(qP).Our findings reveal a medium-high stability level in the qP,with minimal changes over recent *** driving factors vary across landscape types,with climate and anthropogenic factors emerging as crucial *** anthropogenic factors are strong but unstable due to policy changes and economic development,climatic factors exert a consistent *** on our results,we propose site-specific ecological conservation and restoration *** ecological stability assessment framework provides a practical tool to understand the link between environmental conditions and ecosystems.

关键词： Ecological stability assessment framework landscape changes Nature conservation and ecological restoration Nature-based solutions qingzang Plateau

When Fleeing Matters:Differences in Escape Behaviours of Three Northeast Asian Anurans

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Herpetological Research 2024年第1期15卷 41-48页

作者： Yoonjung yi Zoljargal PUREVDORJ Irina MASlOVA yikweon JANG Amaël BORZÉE laboratory of Animal Behaviour and Conservation College of Life SciencesNanjing Forestry UniversityNanjing 210037JiangsuChina Division of EcoScience and Department of life Sciences Ewha Womans UniversitySeoul 03760Republic of Korea Department of Biology School of MathematicsMongolian State University of EducationUlaanbaatar 210648Mongolia Department of Forest and Environmental Resources Chungnam National UniversityDaejeon 34134Republic of Korea Federal Scientific Center of the East Asia Terrestrial Biodiversity Far Eastern Branch of Russian Academy of SciencesVladivostok 690022Russia

Prey species may have their own optimal escape strategy to balance predation risks and the energetic cost of *** species have an advantage when maintaining a short fleeing distance,while others may favour an earlier escape based on microhabitat,size,or body ***,we examined the escape behaviour of the three syntopic Northeast Asian anuran species:Mongolian toads(Strauchbufo raddei),Amur brown frogs(Rana amurensis),and Japanese treefrogs(Dryophytes japonicus)in Mongolia,Russia,China and DPR *** examined flight initiation distance(FID;the distance from a potential predator to the point when the individual starts to flee)and distance fled(DF;distance between flight initiation and flight termination points)of each species and the effects of microhabitat,sex,and body *** raddei and *** had a longer FID than ***,and *** also had a longer DF than *** trends remained similar when dividing FID and DF by a size proxy(snout-vent length)for all *** suggests that the treefrog *** used a strategy to stay immobile even when they were detected,and the toad *** reacted quicker and more sensitively to predators despite the presence of *** *** had a significantly longer FID than males suggesting that females are more sensitive to predation risk in this species,but body size was not significant for any of the three *** results indicate that the three sympatric species have different escaping strategies,likely related to differences in physiology and crypticity.

关键词： amphibian distance fled escape behaviour flight initiation distance predation

Rational design of AgGaS/ZnS/ZnS quantum dots with a near-unity photoluminescence quantum yield via double shelling scheme

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第2期169卷 235-242页

作者： H.X.lu H.liu Z.Z.Fu Y.Y.Chen H.q.Dai Z.Hu W.l.Zhang R.q.Guo Institute for Electric light Sources School of Information Science and TechnologyFudan UniversityShanghai 200433China Institute of Future lighting Academy for Engineering and TechnologyFudan UniversityShanghai 200433China yiwu Research Institute of Fudan University YiwuZhejiang 322000China Zhongshan-Fudan Joint Innovation Center Zhongshan 528437China

In this study,a two-step method was used to synthesize highly luminescent AgGaS/ZnS/ZnS quantum dots(qDs).In the first step,an inner ZnS shell was formed via a one-pot method,which resulted in a smaller lattice mismatch between the AgGaS core and the outer ZnS shell,thereby facilitating the formation of a thick outer *** the two-step shelling process,the synthesized AgGaS/ZnS/ZnS qDs showed an excellent photoluminescence quantum yield(PlqY)of 96.4%with a peak wavelength of 508 nm,repre-senting the highest PlqY reported thus far for AgGaS ***,the effect of halogen ions in Zn precursors on the shelling process was *** was proposed that the capacity of halogen ions to coordinate with the qDs influenced the balance between Zn cation diffusion and ZnS shelling ***,the ZnS shelling reaction was dominant when ZnCl_(2)was employed,while Zn cation diffusion was the dominant process under the I^(−)-rich *** work provides insights into the interfacial restructuring during the ZnS shelling and offers a clear map for the tailored synthesis of core/shell qDs.

关键词： AgGaS quantum dots Photoluminescence Core/shell Alloyed core/shell interface