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Failure behavior of soil-rock mixture slopes based on centrifuge model test

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Journal of Mountain Science 2019年第8期16卷 1928-1942页

作者： WANG Teng ZHANG ga State Key Laboratory of Hydroscience and Engineering Tsinghua University

The stability of soil-rock mixtures(SRMs) that widely distributed in slopes is of significant concern for slope safety evaluation and disaster prevention. The failure behavior of SRM slopes under surface loading conditions was investigated through a series of centrifuge model tests considering various volumetric gravel contents. The displacement field of the slope was determined with image-based displacement system to observe the deformation of the soil and the movement of the block during loading in the tests. The test results showed that the ultimate bearing capacity and the stiffness of SRM slopes increased evidently when the volumetric block content exceeded a threshold value. Moreover, there were more evident slips around the blocks in the SRM slope. The microscopic analysis of the block motion showed that the rotation of the blocks could aggravate the deformation localization to facilitate the development of the slip surface. The high correlation between the rotation of the key blocks and the slope failure indicated that the blocks became the dominant load-bearing medium that influenced the slope failure. The blocks in the sliding body formed a chain to bear the load and change the displacement distribution of the adjacent matrix sand through the block rotation.

关键词： Soil rock mixture Slope stability Slope failure Centrifuge model test

Centrifuge model tests on pile-reinforced slopes subjected to drawdown

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第6期12卷 1290-1300页

作者： Sujia Liu Fangyue Luo ga Zhang State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China

Piles are generally an effective way to reduce the risk of slope ***,previous approaches for slope stability analysis did not consider the effect of the piles coupled with the decrease of the water level(drawdown).In this study,a series of centrifuge model tests was performed to understand the deformation and failure characteristics of slopes reinforced with various pile *** the centrifuge model tests,the pile-reinforced slopes exhibited two typical failure modes under drawdown conditions:across-pile failure and through-pile *** the through-pile slope failure,a discontinuous slip surface was observed,implying that the assumption of the slip surface in previous stability analysis methods was *** test results showed that drawdown led to instability of the piles in cohesive soil,as the saturated cohesive soil failed to provide sufficient constraint for *** slope exhibited progressive failure,from top to bottom,during *** deformation of the piles was reduced by increasing the embedment depth and row number of *** addition,the deformation of soils outside the piles was influenced by the piles and showed a similar distribution shape as the piles,and the similarity degree weakened as the distance from the piles *** study also found that the failure mechanism of unreinforced and pile-reinforced slopes induced by drawdown could be described by coupling between the deformation localization and local failure,and it revealed that pile-reinforced slopes could reduce slope deformation localization during drawdown.

关键词： Slope Pile Drawdown Failure Reinforcement Centrifuge model test

Simplified method for analyzing soil slope deformation under cyclic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第6期14卷 1967-1976页

作者： ga Zhang Yaliang Wang Fangyue Luo State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China

Reasonable assessment of slope deformation under cyclic loading is of great significance for securing the safety of slopes. The observations of centrifuge model tests are analyzed on the slope deformation behavior under cyclic loading conditions. The potential slip surface is the key for slope failure and follows two rules:(i) the relative horizontal displacement along the potential slip surface is invariable at an elevation, and(ii) the soil along the slip surface exhibits the same degradation pattern. These rules are effective regardless of the location of the potential slip surface throughout the entire deformation process of a homogeneous slope, ranging from the initial deformation stage to the failure process and to the post-failure stage. A new, simplified method is proposed by deriving the displacement compatibility equation and unified degradation equation according to the fundamental rules. The method has few parameters that can be determined through traditional element tests. The predictions from the proposed method agree with the centrifuge test results with vertical loading and shaking table loading. This result confirms that the proposed method is effective in predicting the full deformation process of slopes under different cyclic loading conditions.

关键词： Soil slope Cyclic load Deformation Centrifuge model test Slice method

On n-Widths of a Sobolev Function Class in Orlicz Spaces

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Acta Mathematica Sinica,English Series 2015年第9期31卷 1475-1486页

作者： Xiao Li WANG ga Ridi WU College of Statistics and Mathematics Inner Mongolia University of Finance and Economics College of Mathematics Science Inner Mongolia Normal University

This paper considers the problem of n-widths of a Sobolev function class Ωr∞ determined by Pr（D） = DσПlj=1 （D2 - tj2I） in Orlicz spaces. The relationship between the extreme value problem and width theory is revealed by using the methods of functional analysis. Particularly, as σ = 0 or σ = 1, the exact values of Kolmogorov＇s widths, Gelfand＇s widths, and linear widths are obtained respectively, and the related extremal subspaces and optimal linear operators are given.

关键词： n-width extremal subspace optimal linear operator Orlicz space

Development of novel 5-FU modified siRNA against BCL-2 with enhanced efficacy and vehicle-free cellular uptake

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Genes & Diseases 2024年第1期11卷 23-25页

作者： Andrew Fesler ga-Ram Hwang Jingfang Ju Department of Pathology Renaissance School of MedicineStony Brook UniversityStony BrookNY 11794USA The Northport Veteran's Administration Medical Center NorthportNY 11768USA Curamir Therapeutics Inc. WoburnMA 01801USA

One of the major obstacles for nucleic acid-based medicine is cellular uptake due to the concern of efficiencyand potential toxicity of the *** this work,we developed a novel approach to eliminate the need for a vehicle to allow for the cellular uptake of siRNA-based therapy with a unique modification strategy that also further enhances therapeutic *** discovery may be of great importance for the development of siRNA-based therapeutics as cellular uptake remains a critical *** this study,we have tested the potential of this modification strategy for siRNA using a siRNA that targets B-cell lymphoma-2(BCL-2).

关键词： eliminate uptake modified

Tribological properties of polyimide composites reinforced with fibers rubbing against Al_(2)O_(3)

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Friction 2021年第2期9卷 301-314页

作者： Huimin QI ga ZHANG Zhiqin ZHENG Jiaxin YU Chao HU Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education State Key Laboratory of Environment-friendly Energy MaterialsSouthwest University of Science and TechnologyMianyang 621010China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Qingdao Center of Resource Chemistry&New Materials Qingdao 266071China Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory Southwest University of Science and TechnologyMianyang 621010China

Reinforcing fillers are of great importance in tribological performance and tribofilm formation of polymeric *** this study,the tribological properties of aramid particle(AP)and short carbon fiber(SCF)reinforced polyimide(PI)composites were added to hexagonal boron nitride(h-BN),and silica(SiO_(2))nanoparticles sliding against alumina were comprehensively *** sliding occurred with AP-reinforced PI composites,the tribological properties were not closely depended on the pressure×velocity(p×v)factors and the *** interactions between AP and its counterpart could not induce tribo-sintering of the transferred wear *** such,the tribofilm seemed to be in a viscous state,leading to higher friction and ***,the inclusion of hard SCF into the PI matrix changed the interfacial interactions with alumina.A robust tribofilm consisting of a high fraction of silica was generated when the SCF-reinforced PI was added to the SiO_(2) *** exhibited a high load-carrying capability and was easily *** caused a significant decrease in the friction and wear of the PI composite at 8 MPa·1m/***,due to their high melting point,few h-BN nanoparticles were observed in the tribofilm of the SCF-reinforced PI when hexagonal boron nitride was added.

关键词： reinforcing filler polyimide composite tribofilm Al_(2)O_(3)

Anti-vascular endothelial growth factor and macular atrophy:an unanswered question

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Annals of Eye Science 2018年第1期3卷 403-406页

作者： Adam Wylęga.a.Edward Wylęgała Department of Ophthalmology Railway HospitalKatowicePoland 2nd School of Medicine with the Division of Dentistry in Zabrze Medical University of Silesia KatowicePoland

Does anti-vascular endothelial growth factor(VEGF)therapy lead to geographic atrophy?If so,does the number of injections or the duration of anti-VEGF therapy correlate with the risk of developing geographic atrophy?With intravitreal injections becoming the most common ophthalmic invasive procedure and an increasingly aging population,these questions really matter.

关键词： atrophy injections therapy

Analysis of combustion instability via constant volume combustion in a LOX/RP-1 bipropellant liquid rocket engine

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Science China(Technological Sciences) 2012年第4期55卷 1066-1077页

作者： ZHANG HuiQiang ga YongJing WANG Bing WANG XiLin Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China

Turbulent two-phase reacting flow in the chamber of LOX/RP-1 bipropellant liquid rocket engine is numerically investigated in this paper. The predicted pressure and mean axial velocity are qualitatively consistent with the experimental measurements. The self-excited pressure oscillations are obtained without any disturbance introduced through the initial and boundary conditions. It is found that amount of abrupt pressure peaks appear frequently and stochastically in the head regions of the chamber, which are the important sources to drive and strengthen combustion instability. Such abrupt pressures are induced by local constant volume combustion, because local combustible gas mixtures with high temperature are formed and burnt out suddenly due to some fuel droplets reaching their critical state in a rich oxygen surrounding. A third Damkhler number is defined as the ratio of the characteristic time of a chemical reaction to the characteristic time of a pressure wave expansion to measure the relative intensity of acoustic propagation and combustion process in thrusters. The analysis of the third Damkhler number distributions in the whole thrust chamber shows that local constant volume combustion happens in the head regions, while constant pressure combustion presents in the downstream regions. It is found that the combustion instability occurs in the head regions within about 30 mm from the thruster head.

关键词： combustion instability constant volume combustion spray combustion LOX/RP-1 bipropellant liquid rocket engine third Damkohler number

Post-keratoplasty astigmatism management by relaxing incisions:a systematic review

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Eye and Vision 2017年第1期4卷 174-180页

作者： gaëlle Ho Wang Yin Louis Hoffart Ophthalmology Department Aix-Marseille University-APHMHôpital de la Timone264 rue Saint Pierre13385 Marseille Cedex 5France Institut Fresnel UMR 7249 Aix Marseille UniversitéCNRSCentrale MarseilleDomaine universitaire de Saint-Jérôme Avenue Escadrille Normandie Niemen13397 Marseille cedex 20France CERIMED Aix-Marseille University27 Boulevard Jean-Moulin13385 Marseille cedex 05France Ramsay Générale de Santé Clinique Monticelli-VelodromeMarseilleFrance

Postoperative visual acuity can be limited by post-keratoplasty astigmatism,even with a clear corneal *** management can be performed by selective suture removal,adjustment of sutures,optical correction,photorefractive procedures,wedge resection,intra-ocular lens implantation,intracorneal ring segments,relaxing incisions with or without compression sutures and repeated *** incisions can be made in the graft,graft-host interface or host *** the unpredictability of the method because the flat and steep meridians are usually not orthogonal after penetrating keratoplasty,with asymmetric power distribution,all the studies showed an overall reduction of refractive,keratometric or topographic astigmatism,ranging from 30%to 72%with manual or femtosecond-assisted *** patients with astigmatism higher than 6 diopters had residual cylinder less than or equal to 3 diopters,which can be treated by laser excimer ablation or secondary intraocular lens implantation.

关键词： Penetrating keratoplasty Astigmatic keratotomy Relaxing incisions Femtosecond laser