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Structural and photocatalytic characteristics of TiO_(2) coatings produced by various thermal spray techniques

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Journal of Advanced Ceramics 2013年第3期2卷 218-226页

作者： pavel CTIBOR Vaclav STENGL Zdenek PALA Institute of Plasma Physics ASCRv.v.i.Za Slovankou 3PragueCzech Republic Institute of Inorganic Chemistry ASCRv.v.i.Husinec-RezCzech Republic

Titanium dioxide(TiO_(2))was elaborated by four different thermal spray techniques-(i)plasma spraying using a water-stabilized torch,(ii)plasma spraying using a gas-stabilized torch,(iii)high velocity oxy-fuel gun,and(iv)oxy-acetylene *** porosity of the coatings was studied by optical microscopy,nano-structural features by scanning electron microscopy(SEM),phase composition by X-ray diffraction(XRD);the microhardness,surface roughness and wear resistance were *** diffuse reflectance was measured by ultra-violet/visible/near-infrared(UV/Vis/NIR)scanning *** kinetics of photocatalytic degradation of gaseous acetone was measured under a UV lamp with 365 nm *** all the applied spray processes,the transformation of anatase phase from the initial powders to rutile phase in the coatings *** spite of this transformation,all the coatings exhibited certain photocatalytic activity,which correlated well with their band gap energy calculated from *** the coatings offer relatively good mechanical properties and can serve as robust photocatalysts.

关键词： plasma spraying high velocity oxy-fuel(HVOF)spraying flame spraying titanium dioxide(TiO_(2)) photocatalysis band gap

Modelling of microbial enhanced oil recovery application using anaerobic gas-producing bacteria

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Petroleum Science 2014年第2期11卷 272-278页

作者： pavel Spirov Yanina Ivanova Svetlana Rudyk Department of Petroleum and Chemical Engineering Sultan Qaboos University Chemistry & Environment Mrsk Olie og Gas A/S Kanalen 2 DK-6700 Esbjerg

Microbial enhanced oil recovery （MEOR） methods apply injection of bacteria to depleted oil reservoirs to produce oil, which had remained unrecovered after the conventional methods of production. The ability ofthermophilic anaerobic bacteria to produce gas as the main mechanism in potential MEOR in high salinities of 70-100 g/L was investigated in this study. Maximum gas production of up to 350 mL per 700 mL of salty solution was produced at a salinity of 90 g/L stably during 2-4 days of experiment. The experimental results were upscaled to the Snorre Oilfield, Norway, and simulated using ECLIPSE software for 27 months. The best scenarios showed that the increase in oil recovery on average was at 21% and 17.8% respectively. This study demonstrated that anaerobic bacteria used in biogas plants could be an attractive candidate for MEOR implementation due to their ability to withstand high temperature and salinity, and produce gas in large volumes.

关键词： Microbiological enhanced oil recovery CO2 injection ECLIPSE simulation

Treatment of coronary in-stent restenosis： a systematic review

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Journal of Geriatric Cardiology 2018年第2期15卷 173-184页

作者： Leos Pleva pavel Kukla Ota Hlinomaz Department of Cardiovascular Diseases University Hospital Ostrava Czech Republic Department of Cardioangiology St. Anne's University Hospital and Faculty of Medicine Masaryk University Brno CZ Czech Republic International Clinical Research Center St. Anne's University Hospital Brno CZ Czech Republic

Coronary stem implantation has significantly improved percutaneous coronary intervention and enabled the management of early complications of plain balloon angioplasty. However, a new complication has accompanied these improvements： in-stent restenosis （ISR） arising from neointimal hyperplasia. ISR after coronary angioplasty is currently one of the main limitations of this method, leading to the recurrence of exertional angina pectoris or acute coronary syndromes. The clinical incidence of ISR after bare-metal stent （BMS） implantation is approximately 20%35%. The use of drug-eluting stents （DES） has led to a further decrease in the occurrence of ISR to 5%-10%. Evidence resulting from controlled clinical studies suggests that DES and drug-eluting balloon catheters （DEB） provide the best clinical and angiographic results in the treatment of ISR. We undertook a systematic review of the pathophysiology, diagnostics and treatment options for BMS- and DES-ISR. We discuss recent randomised studies, comparing different DES or DEB used for BMS or DES-ISR treatment, as well as the use of new biovascular scafolds and the topic of scafold restenosis.

关键词： Drug-eluting balloon Drug-eluting stent In-stent restenosis

Adipokinetic hormones control amylase activity in the cockroach （Periplaneta americana） gut

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Insect Science 2017年第2期24卷 259-269页

作者： Karolina Bodlakova pavel Jedlicka Dalibor Kodrik Gymnasium Ceska 64 370 21 Ceske Budejovice Institute of Organic Chemistry and Biochemistry CAS Flemingovo sq. 2 166 10 Prague Institute of Entomology Biology Centre CAS and Faculty of Science University of South Bohemia Branisovska 31 370 05 Ceske Budejovice Czech Republic

This study examined the biochemical characteristics of a-amylase and hor- monal （adipokinetic hormone： AKH） stimulation of a-amylase activity in the cockroach （Periplaneta americana） midgut. We applied two AKHs in vivo and in vitro, then measured resultant amylase activity and gene expression, as well as the expression of AKH receptor （AKHR）. The results revealed that optimal amylase activity is characterized by the follow- ing： pH： 5.7, temperature： 38.4 ℃, Km （Michaelis-Menten constant）： 2.54 mg starch/mL, and Vmax （maximum reaction velocity）： 0.185 μmol maltose/mL/min. In vivo application of AKHs resulted in significant increase of amylase activity： by two-fold in the gastric caeca and 4-7 fold in the rest of the midgut. In vitro experiments supported results seen in vivo： a 24-h incubation with the hormones resulted in the increase of amylase activity by 1.4 times in the caeca and 4-9 times in the midgut. Further, gene expression analyses reveal that AKt-IR is expressed in both the caeca and the rest of the midgut, although expression levels in the former were 23 times higher than levels in the latter. A similar pattern was found for the amylase （AMY） gene. Hormonal treatment did not affect the expression of either gene. This study is the first to provide evidence indicating direct AKH stimulation of digestive enzyme activity in the insect midgut, supported by specific AKHR gene expression in this organ.

关键词： AKH AKH receptor amylase enzyme gene expression midgut

Asymptotics for the Korteweg-de Vries-Burgers Equation

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Acta Mathematica Sinica,English Series 2006年第5期22卷 1441-1456页

作者： Nakao HAYASHI pavel I.NAUMKIN Department of Mathematics Graduate School of ScienceOsaka UniversityOsakaToyonaka560-0043Japan Instituto de Matemáticas UNAM Campus MoreliaAP 61-3(Xangari)Morelia CP 58089MichoacánMexico

We study large time asymptotics of solutions to the Korteweg-de Vries-Burgers equation ut＋uux-uxx＋uxxx=0,x∈R,t〉0. We are interested in the large time asymptotics for the case when the initial data have an arbitrary size. We prove that if the initial data u0 ∈H^s （R）∩L^1 （R）, where s 〉 -1/2, then there exists a unique solution u （t, x） ∈C^∞ （（0,∞）;H^∞ （R）） to the Cauchy problem for the Korteweg-de Vries-Burgers equation, which has asymptotics u（t）=t^-1/2fM（（·）t^-1/2）＋0（t^-1/2） as t →∞, where fM is the self-similar solution for the Burgers equation. Moreover if xu0 （x） ∈ L^1 （R）, then the asymptotics are true u（t）=t^-1/2fM（（·）t^-1/2）＋O（t^-1/2-γ） where γ ∈ （0, 1/2）.

关键词： Korteweg-de Vries-Burgers equation asymptotics for large time large initial data

Influence of Chemical Precleaning on the Plasma Treatment Efficiency of Aluminum by RF Plasma Pencil

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Plasma Science and Technology 2016年第4期18卷 430-437页

作者： Vadym PRYSIAZHNYI pavel SLAVICEK Eliska MIKMEKOVA Milos KLIMA Masaryk University Faculty of Science Institute of Scientific Instruments of the ASCR v.v.i.

This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum *** results of our study showed that the state of the topmost surface layer（*** surface morphology and chemical groups）of plasma modified aluminum significantly depends on the chemical *** used chemicals（isopropanol,trichlorethane,solution of Na OH in deionized water）were used as precleaning *** plasma treatments were done using a radio frequency driven atmospheric pressure plasma pencil developed at Masaryk University,which operates in Ar,Ar/O_2 gas *** effectiveness of the plasma treatment was estimated by the wettability measurements,showing high wettability improvement already after 0.3 s *** effects of surface cleaning（hydrocarbon removal）,surface oxidation and activation（generation of OH groups）were estimated using infrared *** changes in the surface morphology were measured using scanning electron *** emission spectroscopy measurements in the near-to-surface region with temperature calculations showed that plasma itself depends on the sample precleaning procedure.

关键词： atmospheric pressure plasma plasma jet aluminum surface treatment surface processing chemical precleaning

Bi-normalized response spectra and seismic intensity in Bucharest for 1986 and 1990 Vrancea seismic events

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Earthquake Engineering and Engineering Vibration 2014年第1期13卷 125-135页

作者： Florin pavel Radu Vacareanu Cristian Neagu Andrei Pricopie Department of Reinforced Concrete Structures Technical University of Civil Engineering BucharestRomania Department of Strength of Materials Bridges and TunnelsTechnical University of Civil Engineering BucharestRomania

The Vrancea subcrustal earthquakes of August 30,1986 and May 30,1990 are the two most recent seismic events that have occurred in Romania with moment magnitudes M W ≥ *** spectral analysis of the strong ground motions recorded in Bucharest reveals that despite small differences in magnitude between the 1986 and 1990 earthquakes,their frequency contents are very different,sometimes even *** main focus of this study is to conduct a comparative analysis of the response spectra in terms of the bi-normalized response spectra(BNRS) proposed by Xu and Xie(2004 and 2007) for strong ground motions recorded in Bucharest during these two seismic *** mean absolute acceleration and relative velocity response spectra for the two earthquakes are discussed and ***,the mean bi-normalized absolute acceleration and normalized relative velocity response spectra with respect to the control period T C are computed for the ground motions recorded in Bucharest in 1986 and *** predominant period T P is also used in this study for the normalization of the spectral period ***,the methodology proposed by Martinez-Perreira and Bommer(1998) is applied in order to estimate the seismic intensity of the two *** results are discussed and several conclusions regarding the possibility of using the bi-normalized response spectra(BNRS) are given.

关键词： response spectra bi-normalized response spectra dynamic amplifi cation factor control period damage potential parameters

Power-law multi-wave model for COVID-19 propagation in countries with nonuniform population density

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Quantitative Biology 2022年第2期10卷 150-156页

作者： pavel Grinchuk Sergey Fisenko A.V.Luikov Heat and Mass Transfer Institute National Academy of Sciences of BelarusMinsk 220072Belarus

Background: The purpose of our study is to develop a quite precise mathematical model which describes epidemics spread in a country with non-uniform population density. This model gives explanation of quite long duration of the peak of a respiratory infection such as the coronavirus disease 2019 (COVID-19).Methods: The theory of kinetic equations and fractal analysis are used in our mathematical model. According to our model, COVID-19 spreading takes the form of several spatio-temporal waves developing almost independently and simultaneously in areas with different population density. The intensity of each wave is described by a power-law dependence. The parameters of the dependence are determined by real statistical data at the initial stage of the disease ***: The results of the model simulation were verified using statistical data for the Republic of Belarus. Based on the developed model, a forecast calculation was made at the end of May, 2020. It was shown that the epidemiological situation in the Republic of Belarus is well described by three waves, which spread respectively in large cities with the highest population density (the first wave), in medium-sized cities with a population of 50−200 thousands people (the second wave), in small towns and rural areas (the third wave). It was shown that a new wave inside a subpopulation with a lower density was born 20−25 days after the appearance of the previous wave. Comparison with actual data several months later showed that the accuracy of forecasting the total number of cases for a period of 3 months for total population in the proposed approach was approximately 3%.Conclusions: The high accuracy mathematical model is proposed. It describes the development of a respiratory epidemic in a country non-uniform population density without quarantine. The model is useful for predicting the development of possible epidemics in the future. An accurate forecast allows to correctly allocating available resources t

关键词： COVID-19 forecast model simultaneous waves population density

Investigation on directional effects of Vrancea subcrustal earthquakes

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Earthquake Engineering and Engineering Vibration 2015年第3期14卷 399-410页

作者： Florin pavel Radu Vacareanu Mircea Radulian Carmen Cioflan Seismic Risk Assessment Center Technical University of Civil Engineering Bucharest National Institute for Earth Physics (INFP)

This paper evaluates possible directional effects from strong ground motions recorded during the last four significant subcrustal earthquakes produced in the Vrancea seismic zone（Romania） in August 1986（Mw=7.1）,May 1990（Mw=6.9 and 6.4） and October 2004（Mw=6.0）.Several measures of the horizontal component of the ground motion given in the literature（Boore et al.,2006;Boore,2010） are computed and are related to the geometric mean of the as-recorded horizontal *** method is applied in order to quantify the influence of the earthquake magnitude and of the soil class on some strong ground motion parameters（*** intensity,PGV/PGA,or mean period TM）.The study of the directional effects is performed using the distribution of IJMAand of the rotation angle corresponding to a measure of the horizontal component of the ground motion（RotD 100） and the results reveal a visible directional pattern for IJMA,while in the case of RotD100 the directional patterns are less visible.

关键词： response spectra horizontal ground motion directio