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In-depth analysis of the influence of bio-silica filler(Didymosphenia geminata frustules)on the properties of Mg matrix composites

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journal of Magnesium and Alloys 2023年第8期11卷 2853-2871页

作者： Izabela B.Zgłobicka Anna Dobkowska Aleksandra Zielińska Ewa Borucinska Mirosław j.Kruszewski RafałZybała Tomasz Płociński joanna Idaszek jakub jaroszewicz Krystian Paradowski Bogusława Adamczyk-Cieślak Kostiantyn Nikiforow Bartosz Bucholc WojciechŚwięszkowski krzysztof j.kurzydłowski Faculty of Mechanical Engineering Bialystok University of TechnologyWiejska 45C15-351 BialystokPoland Faculty of Materials Science and Engineering Warsaw University of TechnologyWoloska 14102-507 WarsawPoland Lukasiewicz Research Network–Institute of Microelectronics and Photonics Al.Lotnikow 32/4602-668 WarsawPoland Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/5201-224 WarsawPoland Institute of Fundamental Technological Research Polish Academy of Sciences Pawinskiego 5B02-106WarsawPoland

A novel metal matrix composites(MMC)with Mg matrix reinforced with natural filler in the form of Didymosphenia geminata frustules(algae with distinctive siliceous shells)are presented in this *** plasma sintering(PPS)was used to manufacture Mg-based composites with 1,5 and 10 vol.%ceramic *** a reference,pure Mg was *** results show that the addition of 1 vol.%Didymosphenia geminata frustules to the Mg matrix increases its corrosion resistance by supporting passivation reactions,and do not affect the morphology of L929 *** of 5 vol.%the filler does not cause cytotoxic effects,but it supports microgalvanic reactions leading to the greater corrosion *** content than 5 vol.%the filler causes significant microgalvanic corrosion,as well as increases cytotoxicity due to the greater micro-galvanic effect of the composites containing 10 and 15 vol.%*** results of contact angle measurements show the hydrophilic character of the investigated materials,with slightly increase in numerical values with addition of amount of ceramic *** addition of Didymosphenia geminata frustules causes changes in a thermo-elastic properties such as mean apparent value of coefficient of thermal expansion(CTE)and thermal conductivity(λ).The addition of siliceous reinforcement resulted in a linear decrease of CTE and reduction in thermal conductivity over the entire temperature *** the increasing addition of Didymosphenia geminata frustules,an increase in strength with a decrease in compressive strain is *** all composites an increase in microhardness was *** results clearly indicate that filler in the form of Didymosphenia geminata frustules may significantly change the most important properties of pure Mg,indicating its wide potential in the application of Mg-based composites with a special focus on biomedical use.

关键词： Metal-matrix composites(MMCs) Pulse plasma sintering(PPS) Ceramic filler Microstructure Properties

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Performance analysis of IEEE 802.11 DCF networks

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journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1309-1317页

作者： krzysztof SZCZYPIORSKI józef LUBACZ Institute of Telecommunications Warsaw University of Technology Nowowiejska 15/19 Warsaw 00-665 Poland

This paper presents an analytical saturation throughput model of IEEE 802.11 DCF (distributed coordination function) with basic access in ad hoc mode. The model takes into account freezing of the backoff timer when a station senses busy channel. It is shown that taking into account this feature of DCF is important in modeling saturation throughput by yielding more accurate and realistic results than models known from literature. The proposed analytical model also takes into account the effect of transmission errors. All essential features of the proposed analytical approach are illustrated with numerical results. The presen-tation of the model is proceeded by an overview of approaches to IEEE 802.11 network performance evaluation presented in the literature.

关键词： IEEE 802.11 Distributed coordination function (DCF) CSMA/CA Modeling

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Numerical assessment of the influence of former mining activities and plasticity of rock mass on deformations of terrain surface

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International journal of Mining Science and Technology 2021年第2期31卷 209-214页

作者： PawełSikora Marek Wesołowski Department of Mining Faculty of MiningSafety Engineering and Industrial AutomationSilesian University of Technology44-100 GliwicePoland

This paper presents the results of numerical simulations carried out to confirm the influence of former mining activities on deformation of the mining *** assessment of deformation changes was carried out with the use of FLAC3 D program based on the finite difference *** calculations were carried out for the example of actual mining operations in seams 703/1-2 and 707/2 of‘‘Marcel"Coal *** into account the influence of the model’s plastic features and the so-called activation of a higher occurring seam in conducted simulations enabled obtaining a very good description of the measured *** on the results one may state that numerical model can be used to assess the influence of former mining activities and the direction of conducted exploitation on deformations of the mining *** factors are not recognized by geometric-integral theories commonly used for predicting the influence of mining operations on the *** results presented in this paper confirm that the applied method of simulating the phenomenon of reactivation of post-mining goafs is correct.

关键词： Rock mass Numerical modeling Post-mining Goafs Land surface deformations

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The Generalized Stackelberg Equilibrium of the Two-Person Stopping Game

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journal of the Operations Research Society of China 2024年第1期12卷 155-168页

作者： Marek Skarupski krzysztof j.Szajowski Faculty of Pure and Applied Mathematics Wroclaw University of Science and Technology50-370WrocƚawDolonoslaskiePoland

In modeling the bilateral selection of states of the process,Dynkin(Dokl Akad Nauk USSR 185:241–288,1969)proposed a two-person game in which players use stopping moments as *** purpose of this work is to present a model of the game in which the players have different information about the process itself,as well as various laws to stop the process and accept its *** game model uses the stochastic process apparatus,in particular,the ability to create different filters for the same *** sets of stopping moments based on different filters are not identical,which allows us to model different sets of strategies for *** show that the follower,by observing the behavior of a rational leader,can recover information that is lost due to the lack of complete observation of the state of the *** the competition of two opponents for the maximum of the ***,one of whom has access to full information and the other only knows their relative ranks,we found the generalized Stackelberg *** the priority of a player observing the relative ranks is less than 50%,then that player modifies his strategy based on the behavior of the second *** a player with full information,information about the behavior of the player observing the relative ranks is useless.

关键词： No-zero-sum game Optional stopping Equilibrium Filtration

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Do mowing regimes affect plant and soil biological activity in the mountain meadows of Southern Poland?

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journal of Mountain Science 2018年第11期15卷 2409-2421页

作者： jóZEFOWSKA Agnieszka ZALESKI Tomasz ZARZYCKI jan FRACZEK krzysztof Institute of Soil Science and Agrophysics Department of Soil Science and Soil Protection University of Agriculture in Krakow Department of Ecology Climatology and Air Protection University of Agriculture in Krakow Department of Microbiology University of Agriculture in Krakow

The soil biological activity of mountain meadows is a significant factor that determines the health and utility of these regions. The climax stage of this area is forest, but to maintain semi-natural grassland, which is characterised by high biodiversity,low-intensity land use(mowing or grazing) is necessarily required. To understand the effect of various mowing regimes on the soil biological activity and plants, the soil microbial activity(microbial biomass carbon, dehydrogenase activity and number of the cultivable fraction of soil microbial community),annelids community(density and species composition earthworms and enchytraeids) and plant species composition were investigated. The study area was located in the Pieniny National Park in the Carpathian Mountains, in a meadow belonging to the association Dactylis glomerata-Poa trivialis. The investigated variants were divided according to mowing regime:traditional scything – hand mowing(HM), mechanical mowing(MM), or the abandonment of mowing – nonmowing(NM). The microbial activities(expressed by,e.g. microbial biomass carbon and the number of phosphorus bacteria) were affected by the mowing regime. The density of earthworms was higher in the HM and MM than in the NM variants. The largest changes in plant species composition were caused by the abandonment of mowing(NM). The mean number of plant species was positively correlated with soil moisture, earthworm density, and microbial activity(expressed indirectly by dehydrogenases activity). The soil microbial community, such as vegetative bacteria forms and ammonifying bacteria,were positively associated with pH value, and the microbial and total organic carbon content. The results presented here indicate that there is no single form of optimal management for all living *** about mowing regimes, or abandonment of use, should be preceded by multi-aspect studies,including plants and soil biota.

关键词： Mowing techniques Grassland management Earthworms Enchytraeids Microorganisms Biodiversity

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Apples to oranges:environmentally derived,dynamic regulation of serotonin neuron subpopulations in adulthood?

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Neural Regeneration Research 2025年第9期20卷 2596-2597页

作者： Christopher j.O’Connell Matthew j.Robson Department of Genetics College of MedicineHarvard UniversityBostonMAUSA james L.Winkle College of Pharmacy Division of Pharmaceutical SciencesUniversity of CincinnatiCincinnatiOHUSA Neuroscience Graduate Program College of MedicineUniversity of CincinnatiCincinnatiOHUSA

Traumatic brain injury(TBI)is a public health problem with an undue economic burden that impacts nearly every age,ethnic,and gender group across the globe(Capizzi et al.,2020).TBIs are often sustained during a dynamic range of exposures to energetic environmental forces and as such outcomes are typically heterogeneous regarding severity and pathology(Capizzi et al.,2020).

关键词： sustained orange dynamic

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INVESTIGATION OF THE ATRP OF n-BUTYL METHACRYLATE USING THE Cu(I)/N,N,N',N",N"-PENTAMETHYLDIETHYLENETRIAMINE CATALYST SYSTEM

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Chinese journal of Polymer Science 2004年第2期22卷 195-204页

作者： Kelly A. Davis krzysztof Matyjaszewski Center for Macromolecular Engineering Department of Chemistry Carnegie Mellon University 4400 Fifth Ave.Pittsburgh Pennsylvania 15213 USACenter for Macromolecular Engineering Department of Chemistry Carnegie Mellon University 4400 Fifth Ave.Pittsburgh Pennsylvania 15213 USA

The polymerization of n-butyl methacrylate was investigated using the Atom Transfer Radical Polymerization technique with CuBr and CuCl/N,N,N',N',N'-pentamethyldiethylenetriamine catalytic systems. Various combinations of catalyst systems and initiators were utilized in order to optimize the polymerization conditions and to obtain well-defined polymers (i.e. controlled molecular weights and low polydispersities). It has been found that the optimal initiator for this system is a chlorine-based initiator, when the catalyst used is a salt in conjunction with the N,N,N',N',N'- pentamethyldiethylenetriamine ligand. Bromine-based initiators tend to result in large amounts of initial termination, leading to polymers with less than ideal chain end functionality, even if CuCl is used as the species to invoke the halogen exchange. Additionally, the effects of the polymerization temperature, species and the initiator structure were determined.

关键词： ATRP Atom transfer radical polymerization Controlled/living radical polymerization Butyl methacrylate Pentamethyldiethylenetriamine

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Effect of Strain Path Reversal on Austenite Grain Subdivision and Deformation Induced Ferrite Transformation Studied by Hot Torsion

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journal of Iron and Steel Research International 2011年第S1期18卷 233-237页

作者： Muszka krzysztof Wynne Bradley P Palmiere Eric j Institute for Microstructural and Mechanical Process Engineering The University of SheffieldMappin StreetSheffield S1 3JDUK

The effects of large strain and strain path reversal on the deformation microstructure evolution in austenite below the recrystallisation temperature were studied by hot torsion using a non-transforming Fe-30wt%Ni model austenitic *** show that the high angle boundaries (HABs) can be generated by both microstructure mechanism through dislocation accumulation and texture mechanism via subgrain ***,multiple strain path reversals lead to less well-developed HABs in the original grains compared to single reversal deformed to the same amount of total accumulative *** effect is attributed to the subgrain rotation mechanism being less effective at small *** comparison,the same hot torsion tests were conducted using a microalloyed steel at a temperature between Ae 3 and Ar *** single strain path reversal,substantial deformation-induced austenite-to-ferrite phase transformation was ***,a test with multiple strain path reversals but with the same total strain produces much lower levels of strain-induced ferrite *** difference is correlated to the observations made in the Fe-30wt%Ni model *** is believed that the different amount of strain-induced ferrite originated from the different levels of strain-induced HABs within the austenite which act as ferrite nucleation sites.

关键词： strain induced transformation ultra fine ferrite dislocation boundaries EBSD

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Challenges in using an analog uncooled microbolometer thermal camera to measure crop temperature

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International journal of Agricultural and Biological Engineering 2014年第4期7卷 60-74页

作者： krzysztof Kusnierek Audun Korsaeth Bioforsk-Norwegian Institute for Agricultural and Environmental Research KappN-2849Norway

It has been long known that thermal imaging may be used to detect stress(*** and nutrient deficiency)in growing *** in microbolometer thermal cameras,such as the introduction of imaging arrays that may operate without costly active temperature stabilization,have vitalized the interest in thermal imaging for crop *** study focused on the challenges occurring when temperature stabilization was omitted,including the effects of focal-plane-array(FPA)temperature,camera settings and the environment in which the measurements were ***,the models for providing thermal response from an analog LWIR video signal(typical output from low-cost microbolometer thermal cameras)were designed and ***,the challenges which typically occur under practical use of thermal imaging of crops were illustrated and discussed,by means of three cereal showcases,including proximal and remotely based(UAV)data *** results showed that changing FPA temperature greatly affected the measurements,and that wind and irradiance also appeared to affect the temperature dynamics ***,it is found that adequate settings of camera gain and offset were crucial for obtaining a reliable *** model which was considered best in terms of transforming video signals into thermal response data included information on camera FPA temperature,and was based on a priori calibrations using a black-body radiation source under controlled *** good calibration(r^(2)>0.99,RMSE=0.32℃,n=96)was obtained for a target temperature range of 15-35℃,covering typical daytime crop temperatures in the growing ***,the three showcases illustrated,that under practical conditions,more factors than FPA temperature may need to be corrected *** conclusion,this study shows that thermal data acquisition by means of an analog,uncooled thermal camera may represent a possible,cost-efficient method for the detection of crop stress,but approp

关键词： analog thermal camera uncooled microbolometer canopy temperature cereals UAV

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Hybrid aqueous capacitors with improved energy/power performance

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Progress in Natural Science:Materials International 2015年第6期25卷 642-649页

作者： jakub Menzel krzysztof Fic Elzbieta Frackowiak Poznan University of Technology Institute of Chemistry and Technical Electrochemistry

This work reports on a high-voltage,hybrid capacitor involving two separate redox *** solutions of Mg(NO3)2and KI have been used for negative and positive electrode,*** p H ? 2 for electrode( t) with KI solution and modifying Mg(NO3)2solution to p H ? 9 for negative side play a crucial role for a stable long-term operation of capacitor at enhanced voltage.A benefit from such a construction is a pseudocapacitive contribution from hydrogen sorption reaction on the negative electrode and high iodine/iodide activity on the positive electrode,enhancing the energy with no remarkable impact on the power *** solution allows a high voltage(1.8 V) to be reached and thereby high power and energy performance( 20 W h/kg at 1 k W/kg) to be *** long-term stability has been confirmed by floating and galvanostatic tests.

关键词： Electrochemical capacitors High-voltage systems Hybrid systems Carbon electrodes Aqueous systems Neutral electrolytes

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