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Wyszukujesz frazę "lattice" wg kryterium: Temat


Tytuł:
On the new characteristics of Miller indices for centered lattices
Autorzy:
Michalski, E.
Powiązania:
https://bibliotekanauki.pl/articles/200839.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Miller indices
families of lattice planes
reciprocal lattice
centered lattice
transformations in crystallography
Laue indices of Bragg reflections
integral systematic absences
transformacje
krystalografia
siatka Bragga
Opis:
This work proposes and justifies a clarification of the description of the crystal structure with the use of centered lattices, and concerns also the following: (1) the graphical and analytical criterion for the existence of lattice planes, described by selected Miller indices, (2) the correct way to use the parametric equation of families of planes, (3) “geometric derivation of the integral reflection conditions” and “Laue indices of Bragg peaks versus Miller indices of families of lattice planes”, (4) the characteristics of Miller indices describing nodes of reciprocal lattices for centered direct lattices, (5) the characteristics of Miller indices describing the faces of single crystals and also (6) the characteristics of the information included in Miller indices. Reciprocal lattice nodes associated with families of lattice planes in direct lattices do not form the centered lattices in the reciprocal space themselves. The centered lattices in reciprocal space are created by points with coordinates equal to the Laue indices of Bragg reflections, which are allowed by the integral systematic absences. Parts of them are not associated with any of the direct lattice planes.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 4; 529-538
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Energy Efficient QAM Modulation with Multidimensional Signal Constellation
Autorzy:
Markiewicz, T. G.
Powiązania:
https://bibliotekanauki.pl/articles/227049.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
communication system
QAM modulation
lattice
multidimensional constellations
Opis:
Packing constellations points in higher dimensions, the concept of multidimensional modulation exploits the idea drawn from geometry for searching dense sphere packings in a given dimension, utilising it to minimise the average energy of the underlying constellations. The following work analyses the impact of spherical shaping of the constellations bound instead of the traditional, hyper-cubical bound. Balanced constellation schemes are obtained with the N-dimensional simplex merging algorithm. The performance of constellations of dimensions 2, 4 and 6 is compared to the performance of QAM modulations of equivalent throughputs in the sense of bits transmitted per complex (twodimensional) symbols. The considered constellations give an approximately 0.7 dB to 1 dB gain in terms of BER over a standard QAM modulation.
Źródło:
International Journal of Electronics and Telecommunications; 2016, 62, 2; 159-165
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lattice rotation definition and predicted textures of tensile and compression deformation
Autorzy:
Wroński, M.
Wierzbanowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/352559.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
axisymmetric deformation
texture
lattice rotation
deformation models
Opis:
The problem of ambiguity in the definition of lattice rotation, used in plastic deformation models, is examined in this work. The geometry of tensile and compression deformation is considered. Two approaches to lattice rotation are considered: the classical definition (called also 'mathematical analysis) and the definition based on orientation preservation of specified directions/planes in the sample coordinates system. Similar study was already done by the present authors for the geometry of rolling deformation. It was shown that application of two rotation definitions enables to explain the appearance of two types of f. c. c. rolling textures: brass type and copper type textures. In the case of axisymmetric deformation the application of both definitions of lattice rotation leads to similar textures, but with different spread of their principal components.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 3; 1529-1536
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model of the two well potential for Hg-atoms in the Hg1-xCdxTe alloy lattice
Autorzy:
Polit, J.
Powiązania:
https://bibliotekanauki.pl/articles/200135.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
well potential
Hg-atoms
Hg1-xCdxTe alloy lattice
Opis:
The problem of the additional phonon modes (APM) of the far infrared spectra in the range of 100–115 cm-1 for the Hg1-xCdxTe alloys has been discussed for the last forty years. The model of two well potential of the mercury atoms in the Hg1-xCdxTe lattice is proposed for interpretation of these APM. Analysis was performed for samples of different compositions (0.06 < x < 0.7) and different types (nand p-type) of conductivity.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 3; 331-341
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving energy compaction of a wavelet transform using genetic algorithm and fast neural network
Autorzy:
Stolarek, J.
Powiązania:
https://bibliotekanauki.pl/articles/964025.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wavelet transform
neural networks
genetic algorithms
signal processing
lattice structure
Opis:
In this paper a new method for adaptive synthesis of a smooth orthogonal wavelet, using fast neural network and genetic algorithm, is introduced. Orthogonal lattice structure is presented. A new method of supervised training of fast neural network is introduced to synthesize a wavelet with desired energy distribution between output signals from low–pass and high–pass filters on subsequent levels of a Discrete Wavelet Transform. Genetic algorithm is proposed as a global optimization method for defined objective function, while neural network is used as a local optimization method to further improve the result. Proposed approach is tested by synthesizing wavelets with expected energy distribution between low– and high–pass filters. Energy compaction of proposed method and Daubechies wavelets is compared. Tests are performed using image signals.
Źródło:
Archives of Control Sciences; 2010, 20, 4; 417-433
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Milling Time on Formation of NiTi Alloy Produced by High-Energy Ball Milling
Autorzy:
Salwa, P.
Goryczka, T.
Powiązania:
https://bibliotekanauki.pl/articles/352287.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
NiTi alloys
high-energy ball milling
crystallite size
microstrain
lattice parameters
Opis:
Mixture of nickel and titanium powders were milled in planetary mill under argon atmosphere for 100 hours at room temperature. Every 10 hours the structure, morphology and chemical composition was studied by X-ray diffraction method (XRD), scanning electron microscope (SEM) as well as electron transmission microscope (TEM). Analysis revealed that elongation of milling time caused alloying of the elements. After 100 hours of milling the powders was in nanocrystalline and an amorphous state. Also extending of milling time affected the crystal size and microstrains of the alloying elements as well as the newly formed alloy. Crystallization of amorphous alloys proceeds above 600°C. In consequence, the alloy (at room temperature) consisted of mixture of the B2 parent phase and a small amount of the B19' martensite. Dependently on the milling time and followed crystallization the NiTi alloy can be received in a form of the powder with average crystallite size from 1,5 up to 4 nm.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 1017-1022
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Milling Time on Formation of NiTi Alloy Produced by High-Energy Ball Milling
Autorzy:
Salwa, P.
Goryczka, T.
Powiązania:
https://bibliotekanauki.pl/articles/354533.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
NiTi alloys
high-energy ball milling
crystallite size
microstrain
lattice parameters
Opis:
Mixture of nickel and titanium powders were milled in planetary mill under argon atmosphere for 100 hours at room temperature. Every 10 hours the structure, morphology and chemical composition was studied by X-ray diffraction method (XRD), scanning electron microscope (SEM) as well as electron transmission microscope (TEM). Analysis revealed that elongation of milling time caused alloying of the elements. After 100 hours of milling the powders was in nanocrystalline and an amorphous state. Also extending of milling time affected the crystal size and microstrains of the alloying elements as well as the newly formed alloy. Crystallization of amorphous alloys proceeds above 600°C. In consequence, the alloy (at room temperature) consisted of mixture of the B2 parent phase and a small amount of the B19’ martensite. Dependently on the milling time and followed crystallization the NiTi alloy can be received in a form of the powder with average crystallite size from 1,5 up to 4 nm.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 4; 1301-1307
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Efficiency Cooling System Using Additive Manufacturing
Autorzy:
Woo, Yeong-Jin
Nam, Dong-Ho
Lee, Seok-Rok
Kim, Eun-Ah
Lee, Woo-Jin
Yang, Dong-Yeol
Yu, Ji-Hun
Park, Yong-Ho
Lee, Hak-Sung
Powiązania:
https://bibliotekanauki.pl/articles/2049198.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
additive manufacturing
DfAM
Design for Additive Manufacturing
cooling system
lattice structure
simulation
Opis:
In this study, we propose a cooling structure manufactured using a specialized three-dimensional (3D) printing design method. A cooling performance test system with complex geometry that used a thermoelectric module was manufactured using metal 3D printing. A test model was constructed by applying additive manufacturing simulation and computational fluid analysis techniques, and the correlation between each element and cooling efficiency was examined. in this study, the evaluation was conducted using a thermoelectric module base cooling efficiency measurement system. The contents were compared and analyzed by predicting the manufacturing possibility and cooling efficiency, through additive manufacturing simulation and computational fluid analysis techniques, respectively.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 689-693
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Investigation on Acoustic Wave Focalization by a Square Lattice Flat Lens
Autorzy:
Alagoz, S.
Powiązania:
https://bibliotekanauki.pl/articles/177219.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
square lattice sonic crystal
wave focusing
plane-wave expansion method
FDTD simulation
Opis:
A sonic crystal consists of a finite-size periodic array of scatters embedded in a background material. One of the fascinating properties of sonic crystals is the focusing phenomenon. In this study, the near field focusing effect of a solid-air 2D sonic crystal lens with a square lattice configuration is investigated in the second frequency band. The band structure and equifrequency contour of the crystal are analyzed to reveal the dispersion of an acoustic wave on the crystal structure. The frequency dependence of the acoustic wave focalization by the sonic crystal flat lens is demonstrated via Finite Difference Time Domain simulation results and experimental measurements.
Źródło:
Archives of Acoustics; 2012, 37, 1; 81-87
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved Framework for Blockchain Application Using Lattice Based Key Agreement Protocol
Autorzy:
Oleiwi, Zahraa Ch.
Dihin, Rasha Ai
Alwan, Ali H.
Powiązania:
https://bibliotekanauki.pl/articles/2200725.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
key agreement protocol
lattice based protocol
mutual authentication
Diffie-Hellman protocol
forward secrecy
Opis:
One of the most recent challenges in communication system and network system is the privacy and security of information and communication session. Blockchain is one of technologies that use in sensing application in different important environments such as healthcare. In healthcare the patient privacy should be protected use high security system. Key agreement protocol based on lattice ensure the authentication and high protection against different types of attack especially impersonation and man in the middle attack where the latticebased protocol is quantum-withstand protocol. Proposed improved framework using lattice based key agreement protocol for application of block chain, with security analysis of many literatures that proposed different protocols has been presented with comparative study. The resultant new framework based on lattice overcome the latency limitation of block chain in the old framework and lowered the computation cost that depend on Elliptic curve Diffie-Hellman. Also, it ensures high privacy and protection of patient’s information.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 1; 5--10
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling, manufacturability and compression properties of the CpTi grade 2 cellular lattice with radial gradient TPMS architecture
Autorzy:
Maszybrocka, J.
Gapiński, B.
Dworak, M.
Skrabalak, G.
Stwora, A.
Powiązania:
https://bibliotekanauki.pl/articles/201748.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
selective laser sintering
additive manufacturing
cellular lattice
triply periodic minimal surfaces
mechanical properties
Opis:
In the present study, a titanium cellular lattice structure with a mathematical designed porosity gradient was successfully fabricated using the selective laser melting method. The samples with smooth gradient transition of porosity of between 60% and 80% were received for different elementary cell geometries. Elementary cells belong to the triply periodic minimal surfaces family (G, D, I2Y, IWP). Each sample was subjected to a comprehensive analysis including: dimensional metrology and assessment of material defects (X-ray micro-tomography), surface morphology tests (scanning electron microscopy) and mechanical properties (universal testing machine). It has been shown that a cellular lattice with high dimensional accuracy (+ 0.16/– 0.08 mm) and full dense struts can be obtained. According to the assumption, the gradient increases the strength of the cellular lattice samples. The highest increase in plateau stress between the samples with and without gradient was found for the I2Y series (about 185%). Furthermore, it was found that the stress-strain response of the samples depends not only on total porosity, but also on the 3D geometry of the cellular lattice. The stress-strain curves for G, IWP and I2Y samples are smooth and exhibit three characteristic regions: linear elasticity, plateau region and densification region. The size of regions depends on the geometric features of the cellular lattice. For series D, in the plateau region, the fluctuations in stress value are clearly visible. The smoothest stress-strain curve can be noted for the G series, which combined with good mechanical properties (the plateau stress and energy absorbed, at respectively 25.5 and 43.2 MPa, and 46.3J and 59.5J for Gyr_80 and Gyr_6080, which corresponds to a strain of almost 65% and 50%) positively affects the applicability of cellular structures with such geometry.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 4; 719-727
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of erythrocyte behaviour in blood capillaries by structural model combined with Lattice-Boltzmann approach
Autorzy:
Przekop, R.
Majewski, I.
Moskal, A.
Powiązania:
https://bibliotekanauki.pl/articles/185673.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Red Blood Cells
Kelvin-Voigt model
lattice Boltzmann
Czerwone krwinki
Model Kelvina-Voigta
krata Boltzmanna
Opis:
A microstructural model of Red Blood Cell (RBC) behaviour was proposed. The erythrocyte is treated as a viscoelastic object, which is denoted by a network of virtual particles connected by elastic springs and dampers (Kelvin-Voigt model). The RBC is submerged in plasma modelled by lattice Boltzmann fluid. Fluid – structure interactions are taken into account. The simulations of RBC behaviour during flow in a microchannel and wall impact were performed. The results of RBC deformation during the flow are in good agreement with experimental data. The calculations of erythrocyte disaggregation from the capillary surface show the impact of RBC structure stiffness on the process.
Źródło:
Chemical and Process Engineering; 2018, 39, 4; 411--426
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape complicated casting defects prediction based on computer simulation
Ocena wad odlewniczych skomplikowanych kształtowo odlewów na podstawie symulacji komputerowych
Autorzy:
Cholewa, M.
Szuter, T.
Powiązania:
https://bibliotekanauki.pl/articles/351270.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
skeleton casting
spatial composite
lattice block structures
periodic metal
odlewy szkieletowe
kompozyt przestrzenny
kratowe struktury blokowe
Opis:
The impact of mould filling parameters on casting defects in shape complicated skeleton casting was investigated. Skeleton castings are low weight cellular material mainly used for energy absorption in for example automotive industry. For prediction of defects such as porosities, the computer simulations of mould filling and solidification were used. In such shape complicated structures like skeleton castings it is very difficult to predict localization of the defects. This knowledge is very important to gain information about deformation mechanisms and for impact behaviour modelling. Series of the skeleton castings were investigated by computer tomography to validate simulations results.
W pracy określono wpływ parametrów wypełniania wnęki formy na miejsca występowania wad odlewniczych w odlewach szkieletowych o rozwiniętej topologii wewnętrznej. Odlewy szkieletowe są produktami komórkowymi o niskiej masie, stosowanymi głównie do absorbowania energii kinetycznej, na przykład w przemyśle motoryzacyjnym. W celu wyznaczenia miejsc prawdopodobnego występowania wad odlewniczych, użyto symulacji komputerowych wypełniania wnęki formy oraz krzepnięcia. W odlewanych elementach szkieletowych, znacznie utrudnione jest precyzyjne określenie potencjalnych miejsc występowania wad. Wiedza ta jest niezbędna, w celu zdobycia informacji o mechanizmach deformacji odlewów szkieletowych. Istotna jest również z punktu widzenia modelowania numerycznego ich zachowania w przypadku odkształceń o dużej dynamice. W celu potwierdzenia wyników symulacji przeprowadzono serie badań z wykorzystaniem tomografii komputerowej.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 3; 859-862
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Filtration Efficiency – from Simple Correlations to Digital Fluid Dynamics
Autorzy:
Przekop, R.
Powiązania:
https://bibliotekanauki.pl/articles/185743.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
filtration
lattice Boltzmann
Brownian dynamics
multiphase flows
porous media
filtrowanie
krata Boltzmanna
Dynamika Browna
przepływy wielofazowe
Opis:
Aerosol filtration in fibrous filters is one of the principal methods of accurate removal of particulate matter from a stream of gas. The classical theory of depth filtration of aerosol particles in fibrous structures is based on the assumption of existing single fibre efficiency, which may be used to recalculate the overall efficiency of entire filter. Using “classical theory” of filtration one may introduce some errors, leading finally to a discrepancy between theory and experiment. There are several reasons for inappropriate estimation of the single fibre efficiency: i) neglecting of shortrange interactions, ii) separation of inertial and Brownian effects, ii) perfect adhesion of particles to the fibre, iv) assumption of perfect mixing of aerosol particles in the gas stream, v) assumption of negligible effect of the presence of neighbouring fibres and vi) assumption of perpendicular orientation of homogenous fibres in the filtration structure. Generally speaking, “classical theory” of filtration was used for characterization of the steady - state filtration process (filtration in a clean filter, at the beginning of the process) without deeper investigation of the influence of the nternal structure of the filter on its performance. The aim of this review is to outline and discuss the progress of deep-bed filtration modelling from the use of simple empirical correlations to advanced techniques of Computational Fluid Dynamics and Digital Fluid Dynamics.
Źródło:
Chemical and Process Engineering; 2017, 38, 1; 31-50
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spider monkey optimization (SMO) - lattice Levenberg-Marquardt recursive least squares based grid synchronization control scheme for a three-phase PV system
Autorzy:
Dash, Dipak Kumar
Sadhu, Pradip Kumar
Subudhi, Bidyadhar
Powiązania:
https://bibliotekanauki.pl/articles/1845508.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solar PV array
VSC
SMO
DC-DC converter
lattice Levenberg–Marquardt recursive least squares
hysteresis current controller
Opis:
This paper presents a new grid integration control scheme that employs spider monkey optimization technique for maximum power point tracking and Lattice Levenberg Marquardt Recursive estimation with a hysteresis current controller for controlling voltage source inverter. This control scheme is applied to a PV system integrated to a three phase grid to achieve effective grid synchronization. To verify the efficacy of the proposed control scheme, simulations were performed. From the simulation results it is observed that the proposed controller provides excellent control performance such as reducing THD of the grid current to 1.75%.
Źródło:
Archives of Control Sciences; 2021, 31, 3; 707-730
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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