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Shock Wave-Boundary Layer Interaction in Forced Shock Oscillations

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Journal of Thermal Science 2003年第1期12卷 10-15页

作者： piotr Doerffer Oskar Szulc Franco Magagnato Institute of Fluid-Flow Machinery Polish Academy of Sciences Fiszera 14Institute of Fluid-Flow Machinery Polish Academy of Sciences Fiszera 14Institute fur Stromungslehre Universitat Karlsruhe Kaiserstr. 12 80-952 Gdansk Poland 80-952 Gdansk Poland D-76128 Karlsruhe Germany

The flow in transonic diffusers as well as in supersonic air intakes becomes often unsteady due to shock wave boundary layer interaction. The oscillations may be induced by natural separation unsteadiness or may be forced by boundary conditions. Significant improvement of CFD tools, increase of computer resources as well as development of experimental methods have *** the attention of researchers to this topic. To investigate the problem forced oscillations of transonic turbulent flow in asymmetric two-dimensional Laval nozzle were considered. A viscous, perfect gas flow, was numerically simulated using the Reynolds-averaged compressible Navier-Stokes solver SPARC, employing a two-equation, eddy viscosity, turbulence closure in the URANS *** time-dependent and stationary flow simulations, Mach numbers upstream of the shock between 1.2 and 1.4 were considered. Comparison of computed and experimental data for steady states generally gave acceptable agreement. In the case of forced oscillations, a harmonic pressure variation was prescribed at the exit plane resulting in shock wave motion. Excitation frequencies between 0 Hz and 1024 Hz were investigated at the same pressure *** main result of the work carried out is the relation between the amplitude of the shock wave motion and the excitation frequency in the investigated range. Increasing excitation frequency resulted in decreasing amplitude of the shock movement. At high frequencies a natural mode of shock oscillation (of small amplitude) was observed which is not sensitive to forced excitement.

关键词： unsteady transonic flow shock wave nozzle flow.

Study of Interaction between Supersonic Flow and Rods Surrounded by Porous Cavity

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Journal of Thermal Science 2006年第4期15卷 324-330页

作者： Minoru YAGA Kenji YAMAMOTO piotr DOERFFER Kenyu OYAKAWA Dept.of Mech.Systems Eng. Univ.of the RyukyusSenbaru 1NishiharaOkinawa903-0213 Graduate student Faculty of Eng.Univ.of the RyukyusSenbaru 1NishiharaOkinawa903-0213 Institute of Fluid Flow Machinery Polish Academy of ScienceFiszera 14PL-80 952 GdanskPoland

In this paper, some preliminary calculations and the experiments were performed to figure out the flow field, in which some rods were normally inserted into the main flow surrounded by a porous cavity. As a result, it is found that the starting shock wave severely interacts with the rods, the bow shock wave, its reflections, and the porous wall, which are numerically well predicted at some conditions. Moreover, inserting the rods makes the pressure on the upper wall in the porous region increase when the main flow in the porous region is completely supersonic. The calculations also suggest that three rods cause the widest suction area.

关键词： shock wave compressible flow porous cavity bow shock wave rod

Analysis of solid sorbents for control and removal processes for elemental mercury from gas streams:a review

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International Journal of Coal Science & Technology 2021年第1期8卷 23-46页

作者： piotr Kunecki Dorota Czarna-Juszkiewicz Magdalena Wdowin Mineral and Energy Economy Research Institute Polish Academy of SciencesWybickiego 7a31-261KrakówPoland

Due to the restriction such as the Minamata Convention as well as the IED of the European Commission,mercury removal from flue gases of coal-fired power plants(CPP)is an increasingly important environmental *** makes this topic very crucial for both the energy industry and *** paper shows how mercury arises from natural resources,i.e.,coals,through their combustion processes in CPP and considers the issue of mercury content in flue gases and solid-state coal combustion *** main part of this paper presents a review of the solid sorbents available for elemental mercury control and removal processes,tested on a laboratory *** described solutions have a potential for wider usage in exhaust gas treatment processes in the energy production *** solutions represent the latest developments in the field of elemental mercury removal from *** authors present an overview of the wide range of solid sorbents and their modifications intended to increase affinity for Hg^(0).Among the presented sorbents are the wellknown activated carbon solutions but also novel modifications to these and other innovative sorbent proposals based on,e.g.,zeolites,biochars,other carbon-based materials,metal-organic *** paper presents a wide range of characteristics of the described sorbents,as well as the conditions for the Hg^(0) removal experiments summarizing the compendium of novel solid sorbent solutions dedicated to the removal of elemental mercury from gases.

关键词： Solid sorbents Textural properties Elemental mercury removal Flue gas Gas stream

Influence of preoperative astigmatism on corneal biomechanics and accurate intraocular pressure measurement after micro-incision phacoemulsification

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International Journal of Ophthalmology(English edition) 2019年第4期12卷 587-591页

作者： Zofia Pniakowska piotr Jurowski Department of Ophthalmology and Visual Rehabilitation the Veterans Central Hospital

AIM: To define the corneal hysteresis(CH), corneal resistance factor(CRF), Goldmann-correlated intraocular pressure(IOPg) and corneal compensated intraocular pressure(IOPcc) prior to and following coaxial micro-incision phacoemulsification in patients with corneal astigmatism. METHODS: Of 97 patients with cataracts were enrolled in the study. Group 1 included patients with corneal astigmatism(K1-K2) values of K1-K2<+1.0 D, and group 2 with values of K1-K2 ≥+1.0 D and ≤+2.25 D. Coaxial micro-incision phacoemulsification of a corneal incision of 2.0 mm with intraocular lens(IOL) implantation was performed. CH, CRF, IOPg, IOPcc, waveform score(WS) were measured preoperatively and one week, one month postoperatively using an Ocular Response Analyzer. Axial length(AXL) was calculated by Tomey Optical Biometer OA ***: Group 1 consisted of 51 patients with mean corneal astigmatism value of +0.49±0.25 D. Group 2 included 46 patients with astigmatism of +1.43±0.43 D. In group 1, CRF(t=2.68, P<0.05), CH(t=2.64, P<0.05) and WS(t=3.51, P<0.05) were significantly lower one week postoperatively, when compared to the preoperative values. CRF significantly decreased(t=3.61, P<0.05) when measured one month following the surgery. In group 2 CH(t=5.92, P<0.05), and WS(t=3.96, P<0.05) were significantly lowered one week after cataract surgery. Moreover, we observed a significant decrease in IOPg(t=2.24, P<0.05), CRF(t=5.05, P<0.05) and CH(t=2.31, P<0.05) one month after phacoemulsification. There was no statistically significant(t=-0.83, P=0.41) difference in AXL between study ***: CRF, CH and IOPg are reduced in patients with preoperative corneal astigmatism equal or higher than +1.0 D and lower than +2.25 D. Hence, bias of IOPg measurement in these patients may cause underestimation of the real IOP both before and after cataract surgery. The measurement of IOPcc allows the precise assessment of IOP pre-and postoperatively, independently on corneal astigmatism,

关键词： corneal astigmatism cataract surgery corneal hysteresis corneal resistance factor intraocular pressure

Iron overload and HFE gene mutations in Polish patients with liver cirrhosis

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Hepatobiliary & Pancreatic Diseases International 2011年第3期10卷 270-275页

作者： Katarzyna Sikorska piotr Stalke Tomasz Romanowski Ewa Izycka-Swieszewska Krzysztof piotr Bielawski Department of Infectious Diseases Medical University of Gdanskul.Smoluchowskiego 1880-218 GdanskPoland Department of Biotechnology Intercollegiate Faculty of BiotechnologyUniversity of Gdansk and Medical University of Gdanskul.Kladki 2480-822 GdańskPoland Department of Pathology Medical University of Gdanskul.Debinki 780-952 GdanskPoland

BACKGROUND:Increased liver iron stores may contribute to the progression of liver injury and fibrosis,and are associated with a higher risk of hepatocellular carcinoma ***-transplant symptoms of iron overload in patients with liver cirrhosis are associated with higher risk of infectious and malignant complications in liver transplant *** gene mutations may be involved in the pathogenesis of liver iron overload and influence the progression of chronic liver diseases of different *** study was designed to determine the prevalence of iron overload in relation to HFE gene mutations among Polish patients with liver ***:Sixty-one patients with liver cirrhosis included in the study were compared with a control group of 42 consecutive patients subjected to liver biopsy because of chronic liver *** function tests and serum iron markers were assessed in both *** patients were screened for HFE mutations (C282Y,H63D,S65C).Thirty-six of 61 patients from the study group and all controls had liver biopsy performed with semiquantitative assessment of iron deposits in ***:The biochemical markers of iron overload and iron deposits in the liver were detected with a higher frequency (70% and 47% respectively) in patients with liver *** were no differences in the prevalence of all HFE mutations in both *** patients with a diagnosis of hepatocellular carcinoma,no significant associations with iron disorders and HFE gene mutations were ***:Iron disorders were detected in patients with liver cirrhosis frequently but without significant association with HFE gene *** the homozygous C282Y mutation seems to occur more frequently in the selected population of patients with liver *** elevated biochemical iron indices accompanied liver iron deposits more frequently in liver cirrhosis compared to controls with chronic liver disease,there is a need for more extensive s

关键词： liver cirrhosis iron overload gene mutations iron deposits hepatocytes

A New Subfamily of Aphids (Hemiptera,Aphidomorpha) from the Early Cretaceous Lebanese Amber with a Description of the Oldest Apterous Morphs

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Acta Geologica Sinica(English Edition) 2010年第4期84卷 665-672页

作者： piotr WEGIEREK David A.GRIMALDI Department of Zoology Silesian University40-0007 KatowicePoland Division of Invertebrate of Zoology American Museum of Natural HistoryNew YorkNY 10024USA

Aphids are marked by their high polymorphism, but species reported from the Early Cretaceous are known only from alate morphs. The discovery of an apterous adult morph in Lebanese amber and a larva of the same species are very important for the understanding of both the morphological and biological evolution of this insect group at the very early stage of development. Gondvanoaphis estephani new subfamily, new genus and species of the recent aphids family Thelaxidae is described. The characters of the new genus in respect to other genera placed in Thelaxidae are reviewed. The palaeoeeological and palaeogeographical data concerning Gondvanoaphis new genus are also discussed.

关键词： Hemiptera Aphidomorpha Thelaxidae Gondvanoaphidinae new subfamily Gondvanoaphis new genus Lebanese amber taxonomy phylogeny fossil insect

Parallel coordinate plots of maize traits under different magnesium applications

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Journal of Integrative Agriculture 2015年第3期14卷 593-597页

作者： Jan Bocianowski piotr Szulc Kamila Nowosad Department of Mathematical and Statistical Methods Poznań University of Life Sciences Department of Agronomy Poznań University of Life Sciences Department of Genetics Plant Breeding and Seed Production Wroclaw University of Environmental and Life Sciences

The parallel coordinate plot is proposed as an efficient tool for visualization of 13 traits of ＂stay-green＂ maize（Zea mays L.） cultivar exposed to different methods of magnesium application. The field experiment was conducted in the Department of Agronomy, Poznań University of Life Sciences, on the fields of the Department of Teaching and Experimental Station in Swadzim in 2006–2008. Experiment was conducted as a single-factor experiment with seven applications of magnesium in a randomized complete block design with four replicates. The highest mean values of grain yield and 1 000-grain weight were obtained after application of variant T3 of magnesium（10 kg MgO ha^–1 soil） in the all three years of study.

关键词： magnesium maize parallel coordinate plots visualization

A new metric for ranking high-performance computing systems

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National Science Review 2016年第1期3卷 30-35页

作者： Jack Dongarra Michael A.Heroux piotr Luszczek Innovative Computing Laboratory EECS DepartmentUniversity of Tennessee

INTRODUCTION Performance benchmarks play an important role in various stages of hardware development and *** development,hardware designers use benchmarks as proxies for full-fledged applications because prototype sys... 详细信息

关键词： code A new metric for ranking high-performance computing systems PDEs NPB high

Permanence of Economic Potential of Cities Based on Sector Development

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Chinese Geographical Science 2017年第1期27卷 123-136页

作者： piotr RAZNIAK Slawomir DOROCKI Anna WINIARCZYK-RAZNIAK Pedagogical University of Cracow ul. Podchorqzych 2 Cracow 30-084 Poland

The paper attempts to answer the following key question: how will a city′s world rank change in the face of crisis in its main economic sector? Crisis is defined here as a decline in financial performance in the given sector, which leads to the decline of its constituent firms and corporations on the world economic scene. The World Economic Center Index(WECI) has been created in order to rank cities based on the value of their resident corporations by sector and show their level of stability upon the removal of the most important sector. This provides information on the potential of each analyzed city as well as on its advanced features or area of specialization. Research has shown that nearly half the World Economic Centers are dominated by the financial and materials sectors of the economy. Different sectors dominate different regions of the world. For example, consumer staples and materials were dominant in North America, while information technology and financials were dominant in Europe. In Asia, several sectors tend to dominate the economy. Research has shown that the ability of a principal economic sector to resist economic crisis largely depends on the strength of the command and control function of a city. Finally, a high globalization level of a city is a key determinant of its susceptibility to economic crisis.

关键词： globalization economic crisis world city world economic center headquarters