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Wyszukujesz frazę "dispersive" wg kryterium: Temat


Tytuł:
Manipulation of the supercontinuum energy distribution based on the positive chirp in photonic crystal fiber
Autorzy:
Yang, H.
Tong, X.
Zhao, S.
Huang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174604.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chirp
dispersive waves
solitons
Opis:
The effect of initial frequency chirp is numerically investigated to obtain high-efficient supercontinuum radiation in photonic crystal fibers with two closely spaced zero-dispersion wavelengths. Our results show that the positive chirp can significantly improve the probability of energy transferred from the soliton to the dispersive wave. And with the increase of the chirp, the energy increases obviously. At the same time, the intensity of the dispersive wave is proportional to the chirp value. Especially, solitons will not appear when the chirp value exceeds 3.9. Therefore, choosing an appropriate positive chirp, we can regulate the energy of the dispersive wave and solitons in photonic crystal fibers.
Źródło:
Optica Applicata; 2018, 48, 1; 75-85
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FDTD analysis of magnetized plasma using an equivalent lumped circuit
Autorzy:
Moryc, A.
Gwarek, W.
Powiązania:
https://bibliotekanauki.pl/articles/309383.pdf
Data publikacji:
2005
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
FDTD
tensor permittivity
dispersive
anisotropic
Opis:
The paper describes a new approach to electromagnetic analysis of magnetized plasma using finite difference time domain (FDTD) method. An equivalent lumped circuit describing an FDTD cell filled with plasma is developed and applied in the analysis. Such a method is proved more effective than previously reported methods. The new approach is verified on a canonical example of known analytical solution.
Źródło:
Journal of Telecommunications and Information Technology; 2005, 2; 75-78
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersion estimates for spherical Schrödinger equations: the effect of boundary conditions
Autorzy:
Holzleitner, M.
Kostenko, A.
Teschl, G.
Powiązania:
https://bibliotekanauki.pl/articles/255331.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Schrödinger equation
dispersive estimates
scattering
Opis:
We investigate the dependence of the [formula] dispersive estimates for one-dimensional radial Schrödinger operators on boundary conditions at 0. In contrast to the case of additive perturbations, we show that the change of a boundary condition at zero results in the change of the dispersive decay estimates if the angular momentum is positive, l ∈ (0,1/2). However, for nonpositive angular momenta, l ∈ (—1/2,0], the standard [formula] decay remains true for all self-adjoint realizations.
Źródło:
Opuscula Mathematica; 2016, 36, 6; 769-786
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radiation-induced cancer risk and decision-making in a simulated Cs-137 urban event
Autorzy:
Andrade, Edson R.
Gomes, Renato G.
Stenders, Ricardo
Brum, Tercio
Lima, Sergio X.
Castro, Mariana S. C.
Silva, Ademir X.
Powiązania:
https://bibliotekanauki.pl/articles/146858.pdf
Data publikacji:
2020
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
environmental contamination
dispersive device
decision-making
Opis:
The triggering of a “dirty bomb” generates a complex scenario, with enormous challenges for the responders due to initial misinformation and the urgency to act quickly yet effectively. Normally, the first 100 h are decisive for perceiving the risk in a more realistic dimension, but the support of methodologies that rely on computational simulations can be valuable when making key decisions. This work seeks to provide support for the early decision-making process by using a Gaussian model for the distribution of a quantity of Cs-137 spread by a radiological dispersive device (RDD). By sequentially joining two independent programs, HotSpot Health Physics codes and RESidual RADiation (RESRAD)-RDD family of codes, we came up with results that suggest a segmented approach to the potentially affected population. These results advocate that (a) the atmospheric stability conditions represented by the Pasquill–Gifford classes and (b) the population subgroups defi ned by radiation exposure conditions strongly influence the postdetonation radiological effects. These variables should be taken into account in the elaboration of flexible strategies that include many climatic conditions and to prioritize attention to different groups of public at risk. During the initial phases of such an event, it is believed that simulations using Gaussian models may be of value in anticipating the possible changes in key variables during the decision-making process. These variables may severely affect the effectiveness of the actions of responders and the general public’s safety.
Źródło:
Nukleonika; 2020, 65, 1; 37-43
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local existence for a viscoelastic Kirchhoff type equation with the dispersive term, internal damping, and logarithmic nonlinearity
Autorzy:
Cordeiro, Sebastião
Raposo, Carlos
Ferreira, Jorge
Rocha, Daniel
Shahrouzi, Mohammad
Powiązania:
https://bibliotekanauki.pl/articles/29519633.pdf
Data publikacji:
2024
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
viscoelastic equation
dispersive term
logarithmic nonlinearity
local existence
Opis:
This paper concerns a viscoelastic Kirchhoff-type equation with the dispersive term, internal damping, and logarithmic nonlinearity. We prove the local existence of a weak solution via a modified lemma of contraction of the Banach fixed-point theorem. Although the uniqueness of a weak solution is still an open problem, we proved uniqueness locally for specifically suitable exponents. Furthermore, we established a result for local existence without guaranteeing uniqueness, stating a contraction lemma.
Źródło:
Opuscula Mathematica; 2024, 44, 1; 19-47
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differences in the development of the Szczecin Lagoon area in the Late Glacial and Holocene based on the geochemical analysis of carbonate sediments from Lake Nowowarpieńskie (NW Poland)
Autorzy:
Strzelecka, Agnieszka
Wróbel, Rafał
Powiązania:
https://bibliotekanauki.pl/articles/2037033.pdf
Data publikacji:
2021-12-23
Wydawca:
Łódzkie Towarzystwo Naukowe
Tematy:
lacustrine chalk
geochemistry
energy dispersive spectroscopy
Littorina transgression
Opis:
This paper presents the results of geochemical analysis performed for the more-than-10-m-long core of sediments derived from Lake Nowowarpieńskie. Contrary to what its geographical name would suggest, it is in fact a peripheral bay  of the Szczecin Lagoon (NW Poland). A characteristic feature of the sedimentary cover of this water body is the several-metre-thick layer of lacustrine chalk, which is unique in the lithology of the sediments of today's Szczecin Lagoon. This sediment has been analysed using atomic absorption spectrometry (AAS), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) imaging. The chalk sediment from Lake Nowowarpieńskie is of chemical origin, bearing no fragments of vascular plants, but only traces of C-org in the form of small plant remains. The analysis of individual crystals using the EDS method also show Ca contents of over 99%. SEM images reveal that the sediment is characterised by a loose, disordered pack-ing of individual crystals, often combined to form aggregates with a tabular structure. The individual calcite grains are usually a few micrometres in size, while developed ones are mostly hypidiomorphic and show signs of corrosion. The sedimentation of the lacustrine chalk indicates that the post-glacial natural development of this part of what today constitutes Szczecin Lagoon differed from that of the rest of the lagoon. This sediment was deposited in a shallow but fertile isolated lake. The full profile of sediments from Lake Nowowarpieńskie reveals its distinct bipartite character, indicating two main stages of its evolution: carbonate and post-carbonate. In the first, the water body showed similarities to the neighbouring lakes of the Wkrzańska Plain. Its evolution was driven by climatic factors. The second stage was initiated by a palaeohydrological factor – Littorina transgression, which resulted in the lake being included into the hydrological system of the Szczecin Lagoon.
Źródło:
Acta Geographica Lodziensia; 2021, 111; 47-57
0065-1249
Pojawia się w:
Acta Geographica Lodziensia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Memory truncation and crosstalk cancellation for efficient Viterbi detection in FDMA systems
Autorzy:
Mertins, A.
Powiązania:
https://bibliotekanauki.pl/articles/309544.pdf
Data publikacji:
2001
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
transmultiplexer
memory truncation
Viterbi detector
dispersive channel
filter banks
Opis:
In this paper, the design of optimal receive filter banks for frequency division multiple access (FDMA) over frequency selective channels is investigated. A new design strategy based on the principle of memory truncation, rather than equalization, is presented. Through the receive filters, each subchannel is truncated to a pre-defined length, and the final data recovery is carried out via low complexity Viterbi detectors. Both closed form designs and adaptive techniques are discussed. Design examples are presented for high speed transmission over copper wires. The examples show that memory truncation allows significant performance improvements over the often used minimum mean squared error (MMSE) equalization.
Źródło:
Journal of Telecommunications and Information Technology; 2001, 3; 29-35
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elevated strontium concentration in the blood of automobile workers in Kolkata
Autorzy:
Basu, R.
Mukhopadhyay, A.
Ray, S.S.
Chakrabarti, P.
Ram, S.S.
Sudarshan, M.
Chakrabarti, S.
Powiązania:
https://bibliotekanauki.pl/articles/1916666.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Medyczny w Białymstoku
Tematy:
Strontium
garage workers
blood
Energy Dispersive X-ray Fluorescence Technique
Opis:
Introduction: Though the trace element strontium’s (Sr) exact role in health remains unknown, at certain levels, it is toxic and, given the body’s low threshold for Sr, has been cited to cause nervous disorders. At different stages of the life cycle, organisms vary in their ability to discriminate Sr and calcium, which can cause age-related differences in gastrointestinal absorption. Though data regarding the effects of such absorption remain limited, it can reportedly impact health, the immune system, and chromosomal aberration. Purpose: To investigate and correlate levels of Sr concentration and any health problems at certain levels among automobile workers. Materials and methods: The blood of 41 automobile workers and 26 healthy controls of the Kolkata region was collected and whole blood Sr concentration estimated by the energy dispersive X-ray fluorescence (EDXRF) technique. Results: Automobile workers showed significantly (p <0.001) higher blood SR levels than controls from the same area, despite similar dietary habits and drinking-water quality. Conclusions: Automobile workers are exposed to different pollutants that can harm their health, and a trace element imbalance of Sr and its elevated concentrations in the blood may cause different health complications.
Źródło:
Progress in Health Sciences; 2014, 4, 2; 186-189
2083-1617
Pojawia się w:
Progress in Health Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and characterisation of unmodified and poly(ethylene glycol) grafted magnesium hydroxide
Autorzy:
Pilarska, A.
Nowacka, M.
Pilarski, K.
Paukszta, D.
Klapiszewski, L.
Jesionowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/109726.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
magnesium hydroxide
poly(ethylene glycols)
modification
dispersive and electrokinetic properties
Opis:
The method for the synthesis of either unmodified magnesium hydroxide or functionalised with poly(ethylene glycols) of different molecular weights and physicochemical properties of the products are presented. Magnesium hydroxide was obtained by the precipitation method under well defined conditions from ammonia solution and different magnesium salts. Dispersive properties of the products were characterised by polydispersity index, particle size, as well as SEM images. Crystalline structure of magnesium hydroxide samples were determined by the WAXS method. To confirm the presence of functional groups introduced by appropriate modifiers the samples were subjected to spectroscopic analysis. Electrokinetic stability of the studied samples was determined on the basis of zeta potential dependence vs. pH measurements. The modification has resulted in reduction of particle diameters in some Mg(OH)2 samples.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 2; 701-712
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersive charge transport in hopping systems under open-circuit conditions: computer simulation
Dyspersyjny transport ładunku w układach przeskokowych w warunkach obwodu otwartego: symulacja komputerowa
Autorzy:
Bąk, G. W.
Powiązania:
https://bibliotekanauki.pl/articles/296536.pdf
Data publikacji:
2012
Wydawca:
Politechnika Łódzka. Wydawnictwo Politechniki Łódzkiej
Tematy:
ruchliwość dryftowa elektronów
transport dyspersyjny
low-mobility materials
dispersive transport
Opis:
Applicability of the theories describing the discharge in thin-film insulators under open-circuit conditions for dispersive hopping systems is the subject of this paper. It is shown by means of computer simulation that the drift mobility obtained from application of the theories for such systems is underestimated. The computer simulation was carried out for a thin film system in which the charge transport is dominated by hopping of charge carriers among localized states in a narrow band at the Fermi level. The way of interpretation of the discharge under opencircuit conditions in such systems is suggested. The simulation results have also been applied for interpretation of the open-circuit discharge in thin diamond-like carbon films.
Badano stosowalność teorii opisujących rozładowanie cienkich warstw izolatorów z przeskokowym transportem ładunku w warunkach obwodu otwartego. Pokazano, że wartości ruchliwości otrzymane w wyniku zastosowania tych teorii do układów dyspersyjnych są niedoszacowane. Symulację wykonano dla układów, w których transport przeskokowy odbywa się w wąskim paśmie w pobliżu poziomu Fermiego. Otrzymane wyniki zastosowano do reinterpretacji wyników badań ruchliwości w warstwach DLC.
Źródło:
Scientific Bulletin. Physics / Technical University of Łódź; 2012, 33; 5-17
1505-1013
2449-982X
Pojawia się w:
Scientific Bulletin. Physics / Technical University of Łódź
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantitative analysis of α-CL-20 polymorphic impurity in ε-CL-20 using Dispersive Raman Spectroscopy
Autorzy:
Ghosh, M.
Venkatesan, V.
Sikder, N.
Sikder, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/951498.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
CL-20
polymorphs
α-CL-20 impurity
Dispersive Raman Spectroscopy
Opis:
α-CL-20 polymorphic impurity in ε-CL-20 studies have been carried out using Dispersive Raman Spectroscopy. ε-, β-, α- and γ-CL-20 polymorphs were produced using crystallization methods with sample recovery from the solution being >90%, and chemical purity of about 99%. The polymorphs prepared were characterized using Dispersive Raman Spectroscopy over the Raman shift region of 100-3500 cm-1 using a 514 nm argon ion laser. The experimental studies were supported by ab initio computations performed at B3LYP level using a 6-31+G** basis set. The computed vibrational frequencies of the CL-20 conformers correspond to the ε, β and α or γ-CL-20 polymorphs when compared with the observed frequencies. α-CL-20 shows a distinct feature at 280 cm-1 as compared with those of the ε-CL-20 polymorph. Using Dispersive Raman Spectroscopy, a linear relationship was demonstrated for the absolute peak height and absolute peak area ratio of α-CL-20 versus the weight percent of α-CL-20. This method enables a detection limit of this polymorphic impurity down to 2 wt%.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 3; 419-438
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of filterbank transceivers for dispersive channels with arbitrary-length impulse response
Autorzy:
Mertins, A.
Powiązania:
https://bibliotekanauki.pl/articles/307670.pdf
Data publikacji:
2003
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
joint transmitter/receiver design
filter banks
information rate maximization
dispersive channels
Opis:
This paper addresses the joint design of transmitter and receiver for multichannel data transmission over dispersive channels. The transmitter is assumed to consist of FIR filters and the channel impulse response is allowed to have an arbitrary length. The design criterion is the maximization of the information rate between transmitter input and receiver output under the constraint of a fixed transmit power. A link to minimum mean squared error designs for a similar setting is established. The proposed algorithm allows a straightforward transmitter design and generally yields a near-optimum solution for the transmit filters. Under certain conditions. the exact solution for the globally optimal transmitter is obtained.
Źródło:
Journal of Telecommunications and Information Technology; 2003, 2; 11-16
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
$L^p$-decay of solutions to dissipative-dispersive perturbations of conservation laws
Autorzy:
Karch, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1294727.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
asymptotic behavior of solutions
dispersive equations
parabolic conservation laws
oscillatory integrals
Opis:
We study the decay in time of the spatial $L^p$-norm (1 ≤ p ≤ ∞) of solutions to parabolic conservation laws with dispersive and dissipative terms added uₜ - uₓₓₜ - νuₓₓ + buₓ = f(u)ₓ or uₜ + uₓₓₓ - νuₓₓ + buₓ = f(u)ₓ, and we show that under general assumptions about the nonlinearity, solutions of the nonlinear equations have the same long time behavior as their linearizations at the zero solution.
Źródło:
Annales Polonici Mathematici; 1997, 67, 1; 65-86
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of MgO to Promote the Oxyethylation Reaction of Lauryl Alcohol
Autorzy:
Pilarska, A.
Lukosek, M.
Siwińska-Stefańska, K.
Pilarski, K.
Jesionowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/779641.pdf
Data publikacji:
2014
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
magnesium hydroxide and oxide
precipitation
dispersive and structural properties
oxyethylation
catalytic activity
Opis:
Synthesis of magnesium hydroxide was performed by the precipitation method with the use of magnesium sulfate and sodium hydroxide. The infiuence of temperature and ratio of reagents was studied. Magnesium hydroxides, and the magnesium oxides obtained from them by thermal decomposition, were analyzed to determine their bulk density, polydispersity and particle size. The magnesium oxide with the largest surface area was tested as a catalyst in the oxyethylation of lauryl alcohol, and shown to be selective but poorly reactive in comparison with commercially available catalysts. Further studies are needed to improve its reactivity.
Źródło:
Polish Journal of Chemical Technology; 2014, 16, 2; 36-42
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of X-ray fluorescence method for elemental analysis of PM2.5 fraction
Autorzy:
Samek, L.
Furman, L.
Kawik, T.
Welnogorska, K.
Powiązania:
https://bibliotekanauki.pl/articles/971541.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
air pollution
energy dispersive X-ray fluorescence (EDXRF)
elemental analysis
particulate matter
Opis:
The scientific interest in air pollution comes from its influence on human health, the condition of cultural heritage and climate. The PM2.5 fraction (particles of a diameter of 2.5 mm or below), indirectly, has a significant impact on health which is associated with respiratory tract and blood vessel related diseases. However, not only the size, but also the content of the particles has a significant meaning. To determine the particulate matter contents, elemental analysis can be performed using numerous techniques, the most important of which is X-ray fluorescence. In this study, samples of PM2.5 fraction collected in Krakow, Poland were analyzed. The X-ray fluorescence method was used to perform elemental analysis. The gravimetric method was applied to determine the concentration of the PM2.5 fraction. Low detection limits of individual elements and precision of the X-ray fluorescence method were determined. The concentrations of the following elements: Cl, K, Ca, Cr, Mn, Fe, Cu, Zn, Br, Rb, Sr and Pb in the PM2.5 fraction samples collected in Krakow were evaluated. The homogeneity of the samples was also estimated. The concentrations of PM2.5 fraction collected in the summer of 2013 were in the range of 6–23 ng/m3. The concentrations of PM2.5 fraction collected in the winter of 2013 were in the range of 26–171 ng/m3. The precision of the method was found to be below 1% for elements with high concentration in the sample and 6–8 % for trace elements.
Źródło:
Nukleonika; 2015, 60, No. 3, part 2; 621-626
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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