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Rock damage and fracturing induced by high static stress and slightly dynamic disturbance with acoustic emission and digital image correlation techniques

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第5期13卷 1002-1019页

作者： Shuting Miao Peng-Zhi Pan petr Konicek Peiyang Yu Kunlun Liu State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China Department of Geomechanics and Mining Research Institute of Geonics of the Czech Academy of SciencesOstrava70800Czech Republic Shenhua Xinjiang Energy Company Limited Urumqi830027China

A series of coupled static-dynamic loading tests is carried out in this study to understand the effect of slightly dynamic disturbance on the rocks under high static *** acoustic emission(AE)and digital image correlation(DIC)techniques are combined to quantitatively characterize the damage and fracturing behaviors of *** effects of three influencing factors,*** static stress,disturbance amplitude,and disturbance frequency,on the damage and fracturing evolution are *** experimental results reveal the great differences in AE characteristics and fracturing behaviors of rocks under static loads and coupled static-dynamic *** the Kaiser effect and Felicity effect are observed during the disturbance loading *** crack initiation,stable and unstable propagation in the highly-stressed rocks can be triggered by cyclic disturbance loads,and more local tensile splitting cracks are found in the rocks subjected to coupled static-dynamic *** damage and fracturing evolution of rocks during cyclic disturbances can be divided into two stages,*** and accelerated stages,and the increase rate and proportion of each stage are greatly affected by these influencing *** initial static stress,low disturbance frequency,and high disturbance amplitude are considered to be adverse factors to the stability of the rocks,which would induce a high increase rate of the steady stage and a high proportion of the accelerated stage within the whole disturbance *** on the two-stage damage evolution trend,a linear-exponential damage model is employed to predict the instability of the rocks under coupled static-dynamic loads.

关键词： Damage evolution Fracture behaviors High static stress Dynamic disturbance Damage model

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Investigation of the Compressible Flow through the Tip-Section Turbine Blade Cascade with Supersonic Inlet

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Journal of Thermal Science 2016年第2期25卷 138-144页

作者： Martin Luxa Jaromír Príhoda David Simurda petr Straka Jaroslav Synác Institute of Thermomechanics AS CR v.v.i. Dolejskova 1402/5 18200 Prague Czech Republic Aerospace Research and Test Establishment Plc Beranovych 130 19905 Prague Czech Republic Doosan Skoda Power Co. Ltd. Tylova 1/57 30128 Pilsen Czech Republic

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.

关键词：可压缩流动涡轮叶栅超声速进气道光学实验湍流模型数值研究叶栅流场配置文件

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Roles of species-preferential seed dispersal by ants and endozoochory in Melampyrum(Orobanchaceae)

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Journal of Plant Ecology 2013年第3期6卷 232-239页

作者： Jan Chlumský petr Koutecký Veronika Jílková Milan Štech University of South Bohemia Faculty of ScienceBranišovská3137005ČeskéBudějoviceCzech Republic

Aims Melampyrum pratense and *** are two myrmeco-chorous species,which possess similar habitat requirements and frequently occur *** this,their population sizes differ *** pratense populations are usually very large,whereas *** has rather small and isolated *** suggest that such an imbalance might be partially influenced by the difference in ant-mediated seed-removal *** Melampyrum is considered to be exclusively myrme-cochorous,though to achieve the recent distribution of some Melampyrum species during the Holocene myrmecochory would be highly *** suggest that endozoochory takes place in the long-distance migration,whereas myrmecochory is important for the removal of seeds on a local *** For seed-preference analysis,*** and *** mixed seed samples were placed around Formica polyctena *** a period of time,the remaining seeds of both species were counted for each *** results were analysed by analysis of variance and generalized linear mixed-effect *** test myrmecochorous removal distances,*** seeds were covered with fluorescent dactyloscopic powder and placed in the vicinity of a large ant *** area around the starting plot was searched in the dark using uV lED torchlight 7 h after the *** distance from the starting plot was measured for each seed ***,rodents,leporine and a ruminant were fed with *** seeds and fresh plants to test the possibility of endozoochorous dispersal of the *** droppings were searched for intact *** Findingsour field studies show that from mixed seed samples,containing both species,ants significantly preferred the seeds of *** may be one of factors that has positive influence on ***-ense success in seed dispersal on mixed stands and consequently in the colonization of favourable *** focusing on ant-mediated dispersal distance reveal

关键词： endozoochory Melampyrum myrmecochory Orobanchaceae seed dispersal

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Germination of Chenopodium Album in Response to Microwave Plasma Treatment

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Plasma Science and Technology 2008年第4期10卷 506-511页

作者： Bo■ena ER Vitězslav STRA■K Michal ER■ Milan TICH■ petr PATENKA Institute of Systems Biology and Ecology Academy of Sciences of the Czech RepublicNa Sádkách 7CZ-370 05eské BudějoviceCzech Republic University of South Bohemia in eské Budějovice Department of PhysicsJeronymova 10CZ-371 15 eské BudějoviceCzech Republic Charles University in Prague Faculty of Mathematics and PhysicsV Holeovikách 2CZ-180 00 Praha 8Czech Republic University of South Bohemia in eské Budějovice Department of PhysicsJeronymova 10 CZ-371 15 eské BudějoviceCzech Republic Technical University of LiberecDepartment of Material SciencesHáIkova 6CZ-461 17 Liberec iCzech Republic

The seeds of Lamb＇s Quarters （Chenopodium album agg.） were stimulated by low- pressure discharge. The tested seeds were exposed to plasma discharge for different time durations （from 6 minutes to 48 minutes）. Germination tests were performed under specified laboratory conditions during seven days in five identical and completely independent experiments. Significant differences between the control and plasma-treated seeds were observed. The treated seeds showed structural changes on the surface of the seat coat. They germinated faster and their sprout accretion on the first day of seed germination was longer. Germination rate for the untreated seeds was 15% while it increased approximately three times （max 55%） for seeds treated by plasma from 12 minutes to 48 minutes.

关键词： early growth germination Lamb's Quarters seed enhancement stimulation surfatron discharge

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Confining MoS_(2) nanocrystals in MOF-derived carbon for high performance lithium and potassium storage

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Green Energy & Environment 2021年第1期6卷 75-82页

作者： Chen Hu Kun Ma Yanjie Hu Aiping Chen petr Saha Hao Jiang Chunzhong Li Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science&TechnologyShanghai200237China Centre of Polymer Systems University InstituteTomas Bata University in ZlinTrida T.Bati 567876001ZlinCzech Republic

Developing an efficient synthesis protocol to simultaneously control 2D nanomaterials’size and dispersion is the pivot to optimize their electrochemical ***,we report the synthesis of uniform MoS_(2) nanocrystals well-anchored into the void space of porous carbon(donated as MoS_(2)3C hybrids)by a simple confined reaction in metal–organic framework(MOF)during carbonization *** strong confinement effect refrain MoS2 growth and aggregation,generating abundant active centers and edges,which contribute fast lithium/potassium reaction *** addition to the hybridization with the derived carbon,the MoS_(2)3C hybrids exhibit rapid Liþtransfer rate(~109 cm^(2) s 1)and greatly improved electronic ***,the MoS23C hybrids show ultrafast rate performances and satisfactory cycling stabilities as anode materials for both lithium and potassium ion *** work demonstrates a universal tactic to achieve high dispersive 2D nanomaterials with tailorable particle size.

关键词： Confined reaction MoS_(2) Nanocrystals Metal–organic framework Energy storage

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Experimental investigation on local shear stress and turbulence intensities over a rough non-uniform bed with and without sediment using 2D particle image velocimetry

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International Journal of Sediment Research 2020年第2期35卷 193-202页

作者： petr Lichtneger Christine Sindelar Johannes Schobesberger Christoph Hauer Helmut Habersack CD-Laboratory of Sediment Research and Management Institute of Water ManagementHydrology and Hydraulic EngineeringDepartment Water-Atmosphere-EnvironmentUniversity of Natural Resources and Life Sciences

The current work focuses on locally resolving velocities,turbulence,and shear stresses over a rough bed with locally non-uniform character.A nonporous subsurface layer and fixed interfacial sublayer of gravel and sand were water-worked to a nature-like bed form and additionally sealed in a hydraulic ***-dimensional Particle Image Velocimetry(2 D-PIV) was applied in the vertical plane of the experimental flume *** with clear water and weak sediment transport were done under slightly supercritical flow to ensure sediment transport conditions without formation of considerable sediment deposits or *** study design included analyzing the double-averaged flow parameters of the entire measurement domain and investigating the flow development at 14 consecutive vertical *** geometrical variabilities as well the presence of sediment were mainly reflected in the vertical velocity *** the vertical velocity decreased over the entire depth in presence of sediment transport,the streamwise velocity profile was reduced only within the interfacial *** the region with decelerating flow conditions,however,the streamwise velocity profile systematically increased along the entire depth *** increase in the main velocity(reduction of flow resistance)correlated with a decrease of the turbulent shear and main normal ***,effects of rough bed smoothening and drag force reduction were experimentally documented within the interfacial sublayer due to mobile ***,the current study leads to the conclusion that in nonuniform flows the maximum Reynolds stress values are a better predictor for the bed shear stress than the linearly extrapolated Reynolds stress *** is an important finding because,in natural flows,uniform conditions are rare.

关键词： Turbulence measurement Local bed shear stress Sediment transport and flow interaction Hydraulic flume experiment Particle image velocimetry

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Warming and altered precipitation rarely alter N addition effects on soil greenhouse gas fluxes: a meta-analysis

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Ecological Processes 2023年 778-790页

作者： Xinyu Wei Fuzhong Wu Koenraad Van Meerbeek Ellen Desie Xiangyin Ni Kai Yue petr Heděnec Jing Yang Nannan An Key Laboratory of Humid Subtropical Eco-Geographical Processes of Ministry of Education School of Geographical Sciences Fujian Normal University Department of Earth and Environmental Sciences Department of Earth and Environmental Sciences KU Leuven Campus Geel Institute of Tropical Biodiversity and Sustainable Development University Malaysia Terengganu

Background Changes in soil greenhouse gas（GHG） fluxes caused by nitrogen（N） addition are considered as the key factors contributing to global climate change（global warming and altered precipitation regimes）, which in turn alters the feedback between N addition and soil GHG fluxes. However, the effects of N addition on soil GHG emissions under climate change are highly variable and context-dependent, so that further syntheses are required. Here,a meta-analysis of the interactive effects of N addition and climate change（warming and altered precipitation）on the fluxes of three main soil GHGs [carbon dioxide（CO2）, methane（CH4）, and nitrous oxide（N2O）] was conducted by synthesizing 2103 observations retrieved from 57 peer-reviewed articles on multiple terrestrial ecosystems *** The interactive effects of N addition and climate change on GHG fluxes were generally additive. The combination of N addition and warming or altered precipitation increased N2O emissions significantly while it had minimal effects on CO2emissions and CH4uptake, and the effects on CH4emissions could not be evaluated. Moreover,the magnitude of the combined effects did not differ significantly from the effects of N addition alone. Apparently,the combined effects on CO2and CH4varied among ecosystem types due to differences in soil moisture, which was in contrast to the soil N2O emission responses. The soil GHG flux responses to combined N addition and climate change also varied among different climatic conditions and experimental *** Overall, our findings indicate that the effects of N addition and climate change on soil GHG fluxes were relatively independent, i.e. combined effects of N addition and climate change were equal to or not significantly different from the sum of their respective individual effects. The effects of N addition on soil GHG fluxes influence the feedbacks between climate change and soil GHG fluxes.

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Helicobacter pylori infection and other bacteria in pancreatic cancer and autoimmune pancreatitis

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World Journal of Gastrointestinal Oncology 2021年第8期13卷 835-844页

作者： Lumir Kunovsky petr Dite petr Jabandziev Jiri Dolina Jitka Vaculova Martin Blaho Martina Bojkova Jana Dvorackova Magdalena Uvirova Zdenek Kala Jan Trna Department of Surgery University Hospital Brno and Faculty of MedicineMasaryk UniversityBrno 62500Czech Republic Department of Gastroenterology and Internal Medicine University Hospital Brno and Faculty of MedicineMasaryk UniversityBrno 62500Czech Republic Department of Gastroenterology and Internal Medicine University Hospital OstravaOstrava 70800Czech Republic Faculty of Medicine University of OstravaOstrava 70300Czech Republic Department of Pediatrics University Hospital Brno and Faculty of MedicineMasaryk UniversityBrno 61300Czech Republic Central European Institute of Technology Masaryk UniversityBrno 62500Czech Republic Department of Intensive Medicine Emergency Medicine and Forensic StudiesUniversity Hospital OstravaOstrava 70800Czech Republic CGB Laboratory a.s.Ostrava Ostrava 70300Czech Republic Department of Gastroenterology and Digestive Endoscopy Masaryk Memorial Cancer InstituteBrno 65653Czech Republic Department of Internal Medicine Hospital BoskoviceBoskovice 68001Czech Republic

Helicobacter pylori(***)is an infectious agent influencing as much as 50%of the world’s *** is the causative agent for several diseases,most especially gastric and duodenal peptic ulcer,gastric adenocarcinoma and mucosaassociated lymphoid tissue lymphoma of the stomach.A number of other,extragastric manifestations also are associated with *** *** include neurological disorders,such as Alzheimer’s disease,demyelinating multiple sclerosis and Parkinson’s *** is also evidence for a relationship between *** infection and such dermatological diseases as psoriasis and rosacea as well as a connection with infection and open-angle *** little is known about the relationship between *** infection and diseases of the *** evidence about *** and its potential role in the development of pancreatic diseases concerns pancreatic adenocarcinoma and autoimmune forms of chronic *** is data(albeit not fully consistent)indicating modestly increased pancreatic cancer risk in ***-positive *** pathogenetic mechanism of this increase is not yet fully elucidated,but several theories have been *** of antral Dcells in ***-positive patients causes a suppression of somatostatin secretion that,in turn,stimulates increased secretin *** stimulates pancreatic growth and thus increases the risk of ***,***,as a part of microbiome dysbiosis and the so-called oncobiome,is proven to be associated with pancreatic adenocarcinoma development via the promotion of cellular *** role of *** in the inflammation characteristic of autoimmune pancreatitis seems to be explained by a mechanism of molecular mimicry among several proteins(mostly enzymes)of *** and pancreatic *** with autoimmune pancreatitis often show positivity for antibodies against *** ***,as a part of microbiome dysbiosis,also

关键词： Helicobacter pylori Pancreatic cancer Autoimmune pancreatitis Carcinogenesis Microbiome Molecular mimicry

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Q-P Process Optimization With the Use of Quenching Dilatometer

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Journal of Iron and Steel Research(International) 2011年第S1期18卷 417-421页

作者： Hauserová Daniela Novy Zbysek Motyka petr Dzugan Jan COMTES FHT a.s. Prumyslová 995334 41 DobranyCzech Republic

The current efforts in production of low-alloyed steels are aimed at achieving high ultimate and yield strengths,while maintaining sufficient elongation and good weldability in these *** advanced heat treatment processes capable of reaching this goal,there is also the Q-P process (Quenching and Partitioning).The process consists in rapid quenching of the material between the M s and M f temperatures in order to prevent full martensitic *** immediately following heating leads to tempering of the martensite and to diffusion of excess carbon from martensite to retained *** increases the stability of the *** aim of the Q-P process is to produce very fine martensite microstructure with retained austenite between martensite *** experimental programme was carried out on a high-strength low-alloyed steel containing 0.2% carbon and a higher amount of silicon about 1.5%.Higher silicon content in the microstructure contributes to stabilization of retained austenite by suppressing formation of *** grade of steel is an advantageous material thanks to its low amount of alloying *** group of low-alloyed steels,if heat treated or thermomechanically treated in a suitable manner,offers a favourable combination of strength,elongation and *** paper is aimed at possibility of the Q-P process optimization with the use of quenching *** experimental material is CMnSiMo *** process optimization consists of standard samples treatment in laboratory furnaces and *** procedure can be time consuming with higher requirements on the experimental ***,it was proposed that the Q-P process optimization can be done with the use of quenching dilatometer and in this way the development of new procedures can be accelerated.Q-P processes were conducted in the standard way and with the aid of a *** of the obtained results provided by the standard procedure and

关键词： Q-P process dilatometer low-alloyed steel

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Applying the Kalman filter particle method to strange and open charm hadron reconstruction in the STAR experiment

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Nuclear Science and Techniques 2023年第10期34卷 148-157页

作者： Xin-Yue Ju Yue-Hang Leung Sooraj Radhakrishnann petr Chaloupka Xin Dong Yury Fisyak Pavol Federic Ivan Kisel Hong-Wei Ke Michal Kocan Spyridon Margetis Ai-Hong Tang Iouri Vassiliev Yi-Fei Zhang Xiang-Lei Zhu Maksym Zyzak University of Science and Technology of China Hefei 230026China Lawrence Berkeley National Laboratory BerkeleyCA 94720USA University of Heidelberg 69120 HeidelbergGermany Kent State University KentOH 44242USA Czech Technical University in Prague PragueCzech Republic Brookhaven National Laboratory UptonNY 11973USA Nuclear Physics Institute of the Czech Academy of Sciences PragueCzech Republic Goethe-Universitat Frankfurt Frankfurt am MainGermany Frankfurt Institute for Advanced Studies Frankfurt am MainGermany GSI Helmholtzzentrum für Schwerionenforschung GmbH DarmstadtGermany Tsinghua University Beijing 100084China

We applied KF Particle, a Kalman Filter package for secondary vertex finding and fitting, to strange and open charm hadron reconstruction in heavy-ion collisions in the STAR experiment. Compared to the conventional helix swimming method used in STAR, the KF Particle method considerably improved the reconstructed Λ, Ω, and D~0 significance. In addition, the Monte Carlo simulation with STAR detector responses could adequately reproduce the topological variable distributions reconstructed in real data using the KF Particle method, thereby retaining substantial control of the reconstruction efficiency uncertainties for strange and open charm hadron measurements in heavy-ion collisions.

关键词： Heavy-ion collisions Secondary vertex finding Kalman filter

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