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Phase field modeling of ferroelastic variant switching in yttria-stabilized t'zirconia with strain gradient elasticity and interface tension

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Science China(Technological Sciences) 2024年第5期67卷 1443-1457页

作者： zhou QianQian wei YueGuang zhou YiChun YANG Li College of Engineering BIC-ESATPeking UniversityBeijing100871China School of Advanced Materials and Nanotechnology Xidian UniversityXi’an710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an710126China

The 6–8 wt%yttria-stabilized zirconia with a tetragonal structure(t’-YSZ)is extensively employed in thermal barrier *** exceptional fracture toughness of t’-YSZ can be attributed to its distinctive ferroelastic toughening *** and interface tension play a critical role in ferroelastic variant switching at the micro-and *** paper presents an original thermodynamically consistent phase field(PF)theory for analyzing ferroelastic variant switching at the micro-and nano-scale of t’-*** theory incorporates strain gradient elasticity using higher-order elastic energy and interface tension tensor via geometric nonlinearity to represent biaxial tension resulting from interface ***,a mixed-type formulation is employed to implement the higher-order theory through the finite element *** an interface in equilibrium,the effects of strain gradient elasticity result in a more uniform distribution of stresses,whereas the presence of interface tension tensor significantly amplifies the stress magnitude at the *** introduction of an interface tension tensor increases the maximum value of stress at the interface by a factor of 4 to *** nucleation and evolution of variants at a pre-existing crack tip in a mono-phase t’-YSZ have also been *** strain gradient elasticity is capable of capturing the size effect of ferroelastic variant switching associated with microstructures in ***,when the grain size approaches that of the specimen,the critical load required for variant switching at the crack tip increases,resulting in greater dissipation of elastic energy during ferroelastic variant ***,the interface tension accelerates the evolution of *** presented framework exhibits significant potential in modeling ferroelastic variant switching at the micro-and nano-scale.

关键词： thermodynamics strain gradient elasticity interface tension phase field method ferroelastic variant switching

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2D all-organic perovskites refine flexible electronics

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Science China Materials 2024年第7期67卷 2365-2366页

作者： wei zhou Bing Chen College of Electronic and Optical Engineering and College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Recent years have witnessed a paradigm shift with the advent of perovskites,a class of materials with a distinct CaTiO_(3)-type crystalline structure that show remarkable promise across a wide array of applications,including photovoltaics,photodetectors,lighting,lasers,and so *** them,the development of two-dimensional(2D)perovskites has garnered significant attention due to their tunable structures(mainly Dion-Jacobson and Ruddlesden-Popper structures)and enhanced stability in comparison with their 3D counterparts[1].Amidst the burgeoning research on perovskites,on the other side,all-organic perovskites stand out as a particularly intriguing subset[2].Unlike traditional perovskites that typically comprise all-inorganic(e.g.,CsPbBr_(3))or organic-inorganic hybrid components(e.g.,(PEA)_(2)PbI_(4)),all-organic perovskites are composed entirely of carbon-or nitrogen-based molecules.

关键词： perovskite inorganic entirely

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A reweighted damped singular spectrum analysis method for robust seismic noise suppression

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Petroleum Science 2024年第3期21卷 1671-1682页

作者： wei-Lin Huang Yan-Xin zhou Yang zhou wei-Jie Liu Ji-Dong Li State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China SINOPEC Petroleum Exploration and Production Research Institute Beijing102206China SINOPEC Geophysical Research Institute Nanjing211103jiangsuChina

(Multichannel)Singular spectrum analysis is considered as one of the most effective methods for seismic incoherent noise *** utilizes the low-rank feature of seismic signal and regards the noise suppression as a low-rank reconstruction ***,in some cases the seismic geophones receive some erratic disturbances and the amplitudes are dramatically larger than other *** presence of this kind of noise,called erratic noise,makes singular spectrum analysis(SSA)reconstruction unstable and has undesirable effects on the final *** robustify the low-rank reconstruction of seismic data by a reweighted damped SSA(RD-SSA)*** incorporates the damped SSA,an improved version of SSA,into a reweighted *** damping operator is used to weaken the artificial disturbance introduced by the low-rank projection of both erratic and random *** central idea of the RD-SSA method is to iteratively approximate the observed data with the quadratic norm for the first iteration and the Tukeys bisquare norm for the rest *** RD-SSA method can suppress seismic incoherent noise and keep the reconstruction process robust to the erratic *** feasibility of RD-SSA is validated via both synthetic and field data examples.

关键词： Singular spectrum analysis Damping operator Seismic erratic noise Seismic signal processing Robust low-rank reconstruction

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Seasonal increase in nest defense,but not egg rejection,in a cuckoo host

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Avian Research 2024年第1期15卷 50-54页

作者： Bo zhou wei Liang Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikou 571158China Institute of Biological Resources Jiangxi Academy of ScienceNanchang 330096China

The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying *** brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood *** test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic *** showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change *** results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.

关键词： Aggression Anti-parasite strategy Egg rejection Mismatch cuckoo parasitism Nest defense

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Shear strength degradation of gas hydrate-bearing sediment due to partial hydrate dissociation

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2749-2763页

作者： Yuan zhou Jiazuo zhou Pan Chen Changfu wei State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China China University of Geosciences Wuhan430074China

Extraction of methane hydrate from subseafloor reservoir may potentially trigger seabed slides and induce *** address the problems,it is crucial to properly characterize the phase equilibrium condition of pore hydrate and the shear strength of the *** one of the key constitutive components,the phase equilibrium condition enforces a constraint over pore gas pressure,temperature and unhydrated water *** a constraint,however,has been traditionally ignored in analyzing the mechanical behavior of hydrate-bearing *** this paper,a series of stepwise hydrate dissociation tests was performed,and the phase equilibrium condition of pore hydrate was determined,providing an effective way to evaluate the unhydrated water content during hydrate ***,a series of direct shear tests was also conducted to explore the shear strength characteristics of the *** is shown that the shear strength of the hydrate-bearing soil can be significantly influenced by pore gas pressure,unhydrated water content,hydrate saturation and several other *** particular,the measured shear strength depends upon the initial water content of the sample,pointing to a potential problem that the shear strength could be wrongly determined if not properly interpreted.A shear strength criterion,which enforces the equilibrium condition of pore hydrate,is developed for hydrate-bearing soil,establishing a link between the equilibrium condition and the shear *** proposed equation describes well the shear strength characteristics of hydrate-bearing soils,remarkably unifying the effects of pore pressure,temperature,water content and hydrate saturation.

关键词： Hydrate-bearing soil Phase equilibrium condition Shear strength Unhydrated water content Mechanical behavior

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A Joint Activity and Data Detection Scheme for Asynchronous Grant-Free Rateless Multiple Access

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China Communications 2024年第1期21卷 34-52页

作者： wei Zhang Xiaofeng Zhong Shidong zhou Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

This paper considers the frameasynchronous grant-free rateless multiple access(FAGF-RMA)scenario,where users can initiate access at any symbol time,using shared channel resources to transmit data to the base *** coding is introduced to enhance the reliability of the *** literature has shown that FA-GFRMA can achieve lower access delay than framesynchronous grant-free rateless multiple access(FSGF-RMA),with extreme reliability enabled by rateless *** support FA-GF-RMA in more practical scenarios,a joint activity and data detection(JADD)scheme is *** the feature of sporadic traffic,approximate message passing(AMP)is exploited for transmission signal matrix ***,to determine the packet start points,a maximum posterior probability(MAP)estimation problem is solved based on the recovered transmitted signals,leveraging the intrinsic power pattern in the *** iterative power-pattern-aided AMP algorithm is devised to enhance the estimation performance of *** results verify that the proposed solution achieves a delay performance that is comparable to the performance limit of FA-GF-RMA.

关键词： asynchronous grant-free JADD rateless codes

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Reconfigurable mechanism-based metamaterials for ternary-coded elastic wave polarizers and programmable refraction control

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1225-1242页

作者： zhou HU Zhibo wei Yan CHEN Rui ZHU School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China School of Mechanical Engineering Tianjin UniversityTianjin300350China Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin300350China

Elastic metamaterials with unusual elastic properties offer unprecedented ways to modulate the polarization and propagation of elastic ***,most of them rely on the resonant structural components,and thus are frequency-dependent and ***,we present a reconfigurable 2D mechanism-based metamaterial which possesses transformable and frequency-independent elastic *** on the proposed mechanism-based metamaterial,interesting functionalities,such as ternarycoded elastic wave polarizer and programmable refraction,are ***,unique ternary-coded polarizers,with 1-trit polarization filtering and 2-trit polarization separating of longitudinal and transverse waves,are first ***,the strong anisotropy of the proposed metamaterial is harnessed to realize positive-negative bi-refraction,only-positive refraction,and only-negative ***,the wave functions with detailed microstructures are numerically verified.

关键词： elastic metamaterial elastic wave reconfigurable design zero mode ternary code programmable refraction

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Effects of Number of Bleed Holes on Shock-Wave/Boundary-Layer Interactions in a Transonic Compressor Stator

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Journal of Thermal Science 2024年第2期33卷 611-624页

作者： LI Bai zhou Xun LUO Lei DU wei School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous *** bleed holes are arranged on the suction surface in a single row,two staggered rows and three staggered *** each bleed scheme,five bleed pressure ratios are examined at an inlet Mach number of *** results indicate that the aerodynamic performance of the cascade is significantly improved by the porous *** the single-row scheme,the maximum reduction in total pressure losses is 57%.For the two-staggered-row and three-staggered-row schemes,there is an optimal bleed pressure ratio of 1.0,and the maximum reductions in total pressure loss are 68% and 75%,*** low loss in the cascade is due to the well-controlled boundary *** new local supersonic region created by the bleed hole is the key reason for the improved boundary *** vortex induced by side bleeding provides another mechanism for delaying flow *** the bleed holes could create multiple local supersonic regions,which reduce the range of the adverse pressure gradient that the boundary layer needs to *** is the reason why cascades with more bleed holes perform better.

关键词： transonic compressor stator shock wave/boundary layer interaction porous bleed number of bleed holes

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A Comprehensive Review of Thermal Performance Improvement of High-Temperature Heat Pipes

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Journal of Thermal Science 2024年第2期33卷 625-647页

作者： CHEN Qihan zhou Jingzhi zhou Guohui CHENG Keyong HuaI Xiulan wei Gaosheng School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing100096China Nanjing Institute of Future Energy System Nanjing211135China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China

Energy efficiency issues are being focused on the growing concern of global warming and environmental *** high-temperature heat pipe(HTHP) is an effective and environmental-friendly heat transfer device employed in many industries,including solar power generation,high-temperature flue gas waste heat recovery,industrial furnaces,nuclear industries,and *** a critical factor in HTHPs,thermal performance is mainly introduced in the entire *** date,most reviews have been published concerning one or several application ***,to the best of authors' knowledge,it is hard to find a review discussing how to improve the thermal performance of HTHPs ***,the impact on the performance of three main components of HTHPs over the past 30 years is introduced:the working fluid,the HTHP structure,and the wick ***,it is a considerable review of the optimal operating conditions for each direction,and we expect this paper contribute to improving the thermal performance of ***,current numerical simulations and theoretical research on the heat transfer limit of HTHPs are *** significant hypotheses used in numerical simulations and the present theoretical studies are compiled ***,some potential future directions and tentative suggestions for HTHP research are put forward.

关键词： high-temperature heat pipe review alkali metal heat pipe thermal performance

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Regulatory Mechanisms for Transcriptional Bursting Revealed by an Event-Based Model

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Research 2024年第3期2023卷 217-231页

作者： Renje Wu Bangyan zhou wei Wang Feng Liu National Laboratory of Solid State Microstructures Department of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093P.R.China Institute for Brain Sciences Nanjing UniversityNanjing 210093P.R.China.

Gene transcription often occurs in discrete bursts, and it can be difficult to deduce the underlying regulatory mechanisms for transcriptional bursting with limited experimental data. Here, we categorize numerous states of single eukaryotic genes and identify 6 essential transcriptional events, each comprising a series of state transitions;transcriptional bursting is characterized as a sequence of 4 events, capable of being organized in various configurations, in addition to the beginning and ending events. By associating transcriptional kinetics with mean durations and recurrence probabilities of the events, we unravel how transcriptional bursting is modulated by various regulators including transcription factors. Through analytical derivation and numerical simulation, this study reveals key state transitions contributing to transcriptional sensitivity and specificity, typical characteristics of burst profiles, global constraints on intrinsic transcriptional noise, major regulatory modes in individual genes and across the genome, and requirements for fast gene induction upon stimulation. It is illustrated how biochemical reactions on different time scales are modulated to separately shape the durations and ordering of the events. Our results suggest that transcriptional patterns are essentially controlled by a shared set of transcriptional events occurring under specific promoter architectures and regulatory modes, the number of which is actually limited.

关键词： kinetics essentially constraints

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