Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "electronic properties" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 19
Tytuł:
Under Pressure DFT Investigations on Optical and Electronic Properties of PbZrO₃
Autorzy:
Nazir, G.
Tariq, Saad
Afaq, A.
Mahmood, Q.
Saad, S.
Mahmood, A.
Tariq, Samar
Powiązania:
https://bibliotekanauki.pl/articles/1030608.pdf
Data publikacji:
2018-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
density functional theory
optical properties
electronic structure
high pressure
Opis:
In this article, density functional theory has been used to investigate the structural and optoelectronic properties of PbZrO₃ (PZO) under pressure from 0 to 350 GPa. In order to achieve ground state structural stability, generalized gradient approximations has been utilized. By studying electronic properties, indirect band-gap nature of PZO appears to change at 15 GPa to direct band-gap. Optical analysis include under pressure responses of real and imaginary parts of dielectric function, optical conductivity, optical absorption coefficient, energy loss function, refractive index, reflectivity and extinction coefficient. Most of the results have been found to be consistent with literature. Study reveals that static dielectric constant and band-gap are in accordance with the Penn model which validates our computed results. Moreover, static dielectric constant and static refractive index directly increases with pressure. Material preserves its positive value of refractive index at all pressures and therefore, it is not a negative index metamaterial. Plasma frequency increases directly with pressure that destabilize the under study material. Our results could be very useful for developing novel optoelectronic devices based on PZO suitable to work under extreme conditions.
Źródło:
Acta Physica Polonica A; 2018, 133, 1; 105-113
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic Phase Diagram and Phonon stability, Electronic and Optical Properties of FeVSb: A DFT study
Autorzy:
Bagheri, A.
Boochani, A.
Masharian, S. R.
Jafarpour, F. H.
Powiązania:
https://bibliotekanauki.pl/articles/2203753.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DFT
thermodynamic phase diagram
phonon
electronic properties
optical properties
Opis:
Mechanical, electronic, thermodynamic phase diagram and optical properties of the FeVSb half-Heusler have been studied based on the density functional theory (DFT) framework. Studies have shown that this structure in the MgAgAs-type phase has static and dynamic mechanical stability with high thermodynamic phase consistency. Electronic calculations showed that this compound is a p-type semiconductor with an indirect energy gap of 0.39 eV. This compound’s optical response occurs in the infrared, visible regions, and at higher energies its dielectric sign is negative. The Plasmon oscillations have occurred in 20 eV, and its refraction index shifts to zero in 18 eV.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 331--338
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Studies of High-nitrogen-containing Energetic Compounds Based on the s-Tetrazine Unit
Autorzy:
Man, T. T.
Wang, K.
Zhang, J.G.
Niu, X. Q.
Zhang, T. L.
Powiązania:
https://bibliotekanauki.pl/articles/358527.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
high-energy-density materials (HEDMs)
substituted s-tetrazine
compounds
electronic properties
thermodynamic properties
detonation
properties
Opis:
In order to develop new high-energy-density materials (HEDMs), we have investigated 12 substituted s-tetrazine (TZ) compounds, where s-tetrazine was substituted by amino, amido and related groups. Density functional theory (DFT) was used to predict the optimized geometries, electronic structures, total energy, heats of formation (HOFs) and densities. In addition the detonation properties were evaluated by using the VLW equation of state (EOS). The standard enthalpy of formation, the Gibbs free energy, entropy and equilibrium constants were used to estimate the success of the synthetic substitution reactions, which provided theoretical support for practical work. The bond dissociation energy (BDE) of bond C-R was calculated at each stage of the substitution reaction. The calculated results showed that substitution of amino, amido and their derivatives in the TZ ring enhances the HOF values and is favorable for increasing the thermal stability. The calculated detonation properties indicated that incorporating the above groups into the TZ ring is benefcial for improving the explosive performance. Considering the detonation properties and thermal stability, the 12 derivatives may be regarded as promising candidates as high-energy-density materials (HEDMs).
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 2; 171-189
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Ru Impurity Effect on Electronic, Optical and Thermoelectric Properties of MoS2 Nano-Sheet: a DFT Study
Autorzy:
Dezfuli, Firouzeh Motamad
Boochani, Arash
Parhizgar, Sara Sadat
Darabi, Elham
Powiązania:
https://bibliotekanauki.pl/articles/2049711.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
MoS2Ru nano-sheet
DFT
electronic properties
optical properties
thermoelectric properties
Opis:
The electronic, optical and thermoelectric properties of MoS2 nano-sheet in presence of the ru impurity have been calculated by density functional theory framework with generalized gradient approximation. The MoRuS2 nano-sheet electronic structure was changed to the n-type semiconductor by 1.3 eV energy gap. The optical coefficients were shown that the loosing optical energy occurred in the higher ultraviolet region, so this compound is a promising candidate for optical sensing in the infrared and visible range. The thermoelectric behaviors were implied to the good merit parameter in the 100K range and room temperatures and also has high amount of power factor in 600K which made it for power generators applications.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 2; 461-468
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Substitution mechanism of rare earths at fluorapatite characteristic sites : experimental and computational calculations
Autorzy:
Xie, Jun
Powiązania:
https://bibliotekanauki.pl/articles/24085936.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rare earth
phosphorite
doping
electronic properties
computational calculations
Opis:
Rare earths (REs) containing phosphate rock is a potential REs resource. The unclear occurrence mechanism of REs in phosphorite limits its further development and utilization. Fluorapatite (FAP) is the main REs-bearing target mineral in phosphorite, the microscopic mechanism of REs entering FAP still needs to be further studied from the electronic scale. In this paper, the doping mechanism of REs in FAP was studied by experiment combined with GGA+U calculation. The XRD, SEM, and FT-IR characterization results of hydrothermal synthesis products showed that REs (La, Ce, Nd, and Y) entered FAP crystal, and one of every 20 Ca atoms was replaced by a REs atom. The GGA+U calculation indicated that La-O/F, Ce-O/F, Nd-O/F, and Y-O/F were ionic bonds in general, and the bonding strength of La-O/F, Ce-O/F, Nd-O/F, and Y-O/F increased gradually with atomic number. The substitution difference of La, Ce, Nd, and Y was mainly caused by the gain and loss of electrons in f and d orbitals. The substitution mechanism of REs at the characteristic sites of Fap was studied, which provided a theoretical reference for the selective recovery of REs from phosphorus blocks.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 2; art. no. 163418
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multistage optical switching networks
Autorzy:
Kaczmarek, S.
Powiązania:
https://bibliotekanauki.pl/articles/309271.pdf
Data publikacji:
2002
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
optical matrix
optical switching networks
electronic switching networks equivalent
connection properties
Opis:
The backbone networks evolution to high-speed DWDM networks generates new problems for switching. This function element must be also based on optical technology. For large capacity this cannot be realized by a single matrix, but by multistage switching networks. In the paper three types of optical matrices have been described: fiber switch FX, wavelength fiber switch WSX and wavelength interchanging fiber switch WIX. Based on these matrices, four switching network constructions were considered. The connection properties of these switching networks were evaluated, determining the electronic equivalent switching network for which these properties are well known.
Źródło:
Journal of Telecommunications and Information Technology; 2002, 2; 21-25
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the deposition process parameters on electronic properties of BN films obtained by means of RF PACVD
Autorzy:
Firek, P.
Werbowy, A.
Szmidt, J.
Kwietniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/308653.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
III-nitrides
thin BN films
electronic properties
RF PACVD
Opis:
This work presents results of investigations of electronic properties of undoped boron nitride (BN) films produced on Si substrates in the course of radio frequency (rf) PACVD process with boron triethyl (C2H5)3B as the boron source. The influence of the deposition process parameters on thickness and electronic properties (resistivity r, dielectric strength EBR) of BN films based on ellipsometry and I-V curve measurements at room temperature is studied. The obtained results show that proper selection of deposition process parameters allows BN layers with the required thickness and advantageous values of r and EBR to be fabricated. BN becomes therefore an interesting material for microelectronics applications.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 3; 33-36
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First-Principles Study of the Structural, Electronic, Magnetic and Thermal Properties of the Cr Doped Ge₆Mn₂Te₈ and Ge₆Fe₂Te₈ Systems
Autorzy:
Semari, F.
Baki, N.
Khachai, H.
Yakoubi, A.
Méçabih, S.
Khenata, R.
Shankar, A.
Rai, D.
Bouhemadou, A.
Powiązania:
https://bibliotekanauki.pl/articles/1030079.pdf
Data publikacji:
2017-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
first-principles calculations
half-metallic ferromagnetism
electronic properties
magnetic moment
spin-exchange splitting
thermodynamic properties
Opis:
First-principles calculations have been used to study the structural, electronic, magnetic, and thermal properties of the Cr doped Ge₆Mn₂Te₈ and Ge₆Fe₂Te₈ systems. The calculations were performed using the full-potential linearized augmented plane wave plus local orbitals (FP-LAPW + LO) method based on the spin-polarized density functional theory. Additionally, the electronic exchange-correlation potential is approximated using the spin generalized gradient approximation. The structural properties of the Ge₅Mn₂CrTe₈ and Ge₅Fe₂CrTe₈ alloys are indicated by their corresponding lattice constants, values of the bulk moduli and their pressure derivatives. An analysis of the band structures and the densities of states indicate that for both alloys, they present nearly half-metallic ferromagnetism character. The band structure calculations are used to estimate the spin-polarized splitting energies, Δp_{x}(d) and Δp_{x}(pd) produced by the 3d Mn, 3d Fe and 3d Cr doped states as well as the s(p)-d exchange constants, N₀α (conduction band) and N₀β (valence band). It is observed that the p-d hybridization reduces the magnetic moment of the Mn and Fe atoms from their atomic charge values and create small local magnetic moments on the nonmagnetic Ge and Te sites. Furthermore, the calculations of the charge density indicate that both compounds have ionic bonding character. Through the quasi-harmonic Debye model, the effects of pressure P and temperature T on the bulk modulus B, the primitive cell volume V/V₀, the Debye temperature θ_{D}, the Grüneisen parameter γ, the heat capacity C_{V}, the entropy S, as well as the thermal expansion coefficient, α of the Ge₆Mn₂Te₈, Ge₅Mn₂CrTe₈, Ge₆Fe₂Te₈ and Ge₅Fe₂CrTe₈ alloys are predicted.
Źródło:
Acta Physica Polonica A; 2017, 132, 4; 1242-1250
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First-Principles Calculations for Structural, Elastic, Electronic and Thermodynamic Properties of $HfZn_{2}$ under Pressure
Autorzy:
Li, Guo-Jun
Shi, Lan-Ting
Hu, Cui-E
Cheng, Yan
Ji, Guang-Fu
Powiązania:
https://bibliotekanauki.pl/articles/1398192.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
C15 Laves-phase
elastic properties
electronic structure
vibrational properties
quasi-harmonic approximation
Opis:
By using density functional theory within the Perdew-Burke-Ernzerhof generalized gradient approximation implemented in the VASP code, we study the structural, elastic, electronic, and thermodynamic properties of C15 Laves-phase compound $HfZn_{2}$. Comparing the lattice constants calculated from the Perdew-Burke-Ernzerhof generalized gradient approximation and local density approximation, we find that the former is in better agreement with the experimental data. The elastic constants of $HfZn_{2}$ calculated by strain-stress method indicate that they keep stable up to 100 GPa. The bonding characteristics are discussed by analyzing the energy band structure, charge density distribution and charge density difference. Phonon dispersion curves and phonon density of states of HfZn_{2} at the different pressure are predicted for the first time. In addition, there is no imaginary frequency in the phonon band at different pressure, which also shows that $HfZn_{2}$ is stable up to 100 GPa. Vibrational models are also illustrated based on phonon and group theory. The thermodynamic properties under high temperature and high pressure are calculated by different thermodynamic models. The heat capacity at constant pressure and low temperature calculated by quasi-harmonic approximation is more close to the measurement than that calculated by quasi-harmonic Debye models.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1299-1306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First Principle Investigations on Electronic, Magnetic, Thermodynamic, and Transport Properties of TlGdX₂ (X = S, Se, Te)
Autorzy:
Gautam, R.
Kumar, A.
Singh, R.
Powiązania:
https://bibliotekanauki.pl/articles/1032602.pdf
Data publikacji:
2017-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
semiconductors
electronic structure
magnetic properties and thermodynamic properties
Opis:
In the present research paper, we investigated spin polarized electronic, magnetic, thermodynamic, and transport properties of thallium gadolinium dichalcogenides TlGdX₂ (X = S, Se, Te) using density functional theory. Electronic structure reveals that all the three compounds are wide band gap semiconductors which are beneficial for good thermoelectric performance. Calculated magnetic moment of TlGdX₂ is found to be in good agreement with available experimental values and mainly dominant by Gd³⁺ ions. Semiclassical Boltzmann transport theory has been used to calculate the Seebeck coefficient and electrical conductivity for the proposed dichalcogenides. Calculated values of the Seebeck coefficient and electrical conductivity are found to be consistent with available experimental values in literature. Thermodynamic properties of TlGdX₂ have also been estimated for the first time and explained on the basic facts.
Źródło:
Acta Physica Polonica A; 2017, 132, 4; 1371-1378
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic-and-optical properties of Rb2ZnCl4 crystals
Autorzy:
Andriyevsky, B.
Kurlyak, V.
Stadnyk, V.
Romanyuk, M.
Stakhura, V.
Powiązania:
https://bibliotekanauki.pl/articles/118460.pdf
Data publikacji:
2015
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
właściwości elektronowo-optyczne kryształów
kryształy Rb2ZnCl4
obliczenia ab initio
współczynnik załamania
komórka elementarna kryształu
electronic-and-optical properties crystal
Rb2ZnCl4 crystal
Ab initio calculations
refractive indices of Rb2ZnCl4
crystal unit cell
Opis:
Electronic-and-optical properties of Rb2ZnCl4 crystal have been studied using the theoretical and experimental methods. First principles calculations of the electronic structure and optical properties using the density functional theory have been performed on the relaxed and uniaxially compressed (1 GPa) Rb2ZnCl4 crystal. The refractive indices of Rb2ZnCl4 have been measured in the spectral range of wavelength 300 nm to 750 nm for three principal uniaxial compression stresses (0.02 GPa) at room temperature. Ab initio calculations and analysis have revealed that the observed uniaxial pressure changes of the refractive indices of Rb2ZnCl4 are caused mainly by the corresponding changes of the crystal unit cell dimensions. The unit cell electronic polarizability of the crystal remains approximately unchanged.
Zbadano właściwości elektronowo-optyczne kryształów Rb2ZnCl4 metodami teoretyczną i doświadczalną. Wykonano obliczenia z pierwszych zasad (ab initio) struktury elektronowej i właściwości optycznych na bazie teorii funkcjonału gęstości zrelaksowanych i jednoosiowo ściśniętych (1 GPa) kryształów. Zostały pomierzone współczynniki załamania Rb2ZnCl4 w przedziale długości fal światła 300 nm do 750 nm dla trzech głównych krystalograficznych kierunków ściskania (0.02 GPa) przy temperaturze pokojowej. Obliczenia ab initio i analiza danych ujawniły, że obserwowane baryczne zmiany współczynników załamania Rb2ZnCl4 są spowodowane głównie odpowiednimi zmianami rozmiarów komórki elementarnej kryształu. Przy tym, polaryzowalność elektronowa komórki kryształu pozostaję się prawie niezmienną.
Źródło:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej; 2015, 8; 5-14
1897-7421
Pojawia się w:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic structure, stability, and strength of Cu–NiAl alloys : experiment and DFT investigation
Autorzy:
Zarhri, Zakaryaa
Powiązania:
https://bibliotekanauki.pl/articles/2074202.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
mechanical properties
electronic structure
DFT study
Cu-doped nickel aluminide
formation energy
Opis:
In this study, the copper doping effect on the NiAl structural stability, strength, and electronic structure was investigated. The samples were prepared using induction melting at 2073 K. This material presents good mechanical and physical properties such as high-temperature strength, fatigue or impact, and corrosion resistance which meet technical requirements of many applications. The microstructure of the Cu-doped nickel aluminide was studied using a metallurgical microscope and its lattice parameter was also studied and characterized using an X-ray diffractometer for different concentrations of Cu. The lattice constant of the existing phases was calculated, and it was found that the lattice distortion and gamma prime phase energy have high values allowing the increase of the entropy term of the alloy and subsequently increasing its hardness. From the ab-initio calculation, it was determined that the Cu atoms have the Al sites as a preferred site and prefer to bond with Ni atoms which leads to the improvement of the material hardness. Ab-initio density functional theory was applied to study the formation energy that revealed increasing with Cu amount.
Źródło:
Opto-Electronics Review; 2022, 30, 2; art. no. e141707
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic, optical and non-linear optical properties of an N-cyclohexylacrylamide molecule : a potential optoelectronic agent
Autorzy:
Tanış, E.
Çankaya, N.
Powiązania:
https://bibliotekanauki.pl/articles/1818235.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
N-cyclohexylacrylamide
electronic properties
optical properties
non-linear optical properties
DFT
Opis:
In this article, synthesis, electronic and optical properties of an N-cyclohexyl-acrylamide (NCA) molecule are described based on different solvent environments and supported by theoretical calculations. Theoretical calculations have been carried out using a density function theory (DFT). Temperature dependence of the sample electrical resistance has been obtained by a four-point probe technique. Experimental and semitheoretical parameters such as optical density, transmittance, optical band gap, refractive index of the NCA for different solvents were obtained. Both optical values and electrical resistance values have shown that NCA is a semiconductor material. The values of HOMO and LUMO energy levels of the headline molecule indicate that it can be used as the electron transfer material in OLEDs. All results obtained confirm that the NCA is a candidate molecule for OLED and optoelectronic applications.
Źródło:
Opto-Electronics Review; 2020, 28, 4; 191--196
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of oxidation and mechanical damage of PCBs with OSP finish on their solderability with SAC305 alloy
Wpływ utleniania i uszkodzeń mechanicznych powierzchni płytek PCB z pokryciem OSP na ich lutowność stopem SAC305
Autorzy:
Kudyba, A.
Siewiorek, A.
Sobczak, N.
Turalska, P.
Powiązania:
https://bibliotekanauki.pl/articles/391438.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
surfaces
coatings
electronic characterization
defects
surface properties
solderability
wetting balance test
powłoki
wady
właściwości powierzchni
lutowność
badania meniskograficzne
Opis:
The paper focuses on the experimental investigation of wetting behavior and solderability of commercial lead-free solder on Printed Circuit Board (PCB) covered with an OSP finish (Organic Surface Protectant) characterized by physical (mechanically scratched) and/or chemical (oxidized in air at 260°C for 1 hour) inhomogeneity of the surface finish. The influence of the quality of the PCB finish on the maximum wetting force Fmax, wetting time t0, the contact angle θ, and the parameters characterizing solderability, were studied. The tests were performed by a wetting balance method with SAC305 solder (Sn-3.0Ag-0.5Cu, wt. %) and commercial flux (EF2200) using MENISCO ST88 apparatus allowing direct measurement of the wetting force Fr and wetting time t0 as well as calculation of the contact angle θ values. The measurements were made at a temperature of 260°C for a contact time of 3 s. For comparison, the tests were also performed on PCBs in delivery state showing average Fmax = 0.9 mN, t0 = 0.58 s and θ = 57°. The results have shown that both oxidation and mechanical damage of the OSP finish have a significant worsening effect on solderability. Scratched OSP finish had an average Fmax = -1.03 mN and θ = 78°. Such surfaces were non-wettable with corresponding values of Fmax = -4.7 mN and θ = 120° for oxidized samples and Fmax = -4.04 mN and θ = 111° for those scratched and oxidized.
W pracy badano zwilżalność i lutowność płytek drukowanych (PCB) z pokryciem OSP, które charakteryzowały się niejednorodnością występującą na powierzchni: były mechanicznie porysowane i/lub utlenione (na powietrzu, w temperaturze 260°C w czasie 1 godziny). Do badań stosowano komercyjny stop bezołowiowy. Określono wpływ jakości pokrycia na wartość maksymalnej siły zwilżania Fmax, czas zwilżania t0 i kąt zwilżania θ, czyli parametrów charakteryzujących lutowność. Badania prowadzono metodą zanurzeniową (meniskograficzną) na aparaturze ST88 MENISCO, która umożliwia bezpośredni pomiar siły zwilżania Fr i czasu zwilżania t0, jak również obliczenie wartości kąta zwilżania θ. Pomiary przeprowadzono w temperaturze 260°C w czasie 3 s. Dla porównania testy przeprowadzono również na płytkach „w stanie dostawy”, uzyskując średnią Fmax = 0.9 mN, t0 = 0,58 s i θ = 57°. Uzyskane wyniki świadczą, że zarówno utlenianie powierzchni, jak i uszkodzenia mechaniczne pokrycia OSP powodują znaczące pogorszenie lutowości płytek PCB. Dla pokrycia OSP, które było porysowane, uzyskano średnio Fmax = -1,03 mN i θ = 78°. Dla próbek utlenionych mierzone wartości wyniosły: Fmax = -4,7 mN i θ = 120°, natomiast dla próbek porysowanych i utlenionych: Fmax = -4,04 mN i θ = 111°.
Źródło:
Prace Instytutu Odlewnictwa; 2015, T. 55, nr 4, 4; 59-66
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of crystal defects on the electronic structure and dielectric functions of In0.5Tl0.5I solid state solutions
Autorzy:
Andriyevsky, Bohdan
Kashuba, A.
Ilchuk, H.
Powiązania:
https://bibliotekanauki.pl/articles/118313.pdf
Data publikacji:
2019
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
semiconductors
point defects
electronic band structure
electrical transport
optical properties
computer simulations
półprzewodniki
wada punktowa
struktura pasmowa
transport elektryczny
właściwości optyczne
symulacje komputerowe
Opis:
We investigate an influence of the various crystal structure imperfections on the electronic properties and dielectric functions for In0.5Tl0.5I semiconductor in the frame of the density functional theory calculations. The tensor of electron effective mass m*ij of InI, In0.5Tl0.5I and TlI crystals has been calculated for the valence and conduction bands and different K-points of Brillouin zone. Dielectric functions ε(hν) of the defective crystals based on In0.5Tl0.5I solid state solution with iodine vacancy and thallium interstitial atom were calculated taking into consideration the inter-band and intra-band electron transitions. The studies of the defective crystals reveal increased low-frequency and stationary electron conductivity with anisotropy resulted from the anisotropy of the electron effective mass tensor. Our findings explain the origin of crucial changes in the band structure by formation the donor half-occupied levels close to the unoccupied conduction bands due to the crystal structure defects, i.e. iodine vacancy or thallium interstitial atom. It has been shown that in the case of real crystals, in particular metal-halides, the proper consideration of defects in quantum-chemical calculations results in a better matching of the theoretical and experimental results in comparison to the case when the perfect crystal structure had been used for calculations.
Zbadano wpływ różnych niedoskonałości struktury krystalicznej na właściwości elektronowe i funkcje dielektryczne półprzewodnika In0.5Tl0.5I w ramach teorii funkcjonału gęstości. Został obliczony tensor efektywnej masy elektronów m* kryształów InI, In0.5Tl0.5I i TlI dla pasm walencyjnych i przewodnictwa oraz różnych K-punktów strefy Brillouina. Funkcje dielektryczne ε(hν) domieszkowanych kryształów roztworów stałych In0.5Tl0.5I z wakansami jodu i atomami międzywęzłowymi talu zostały obliczone z uwzględnieniem międzypasmowych i wewnątrz-pasmowych przejść elektronowych. Badania domieszkowanych kryształów ujawniły zwiększoną przewodność elektronową niskoczęstotliwościową i stacjonarną o anizotropii wynikającej z anizotropii tensora efektywnej masy elektronów. Przeprowadzone badania wyjaśniają obserwowane duże zmiany struktury pasmowej pochodzące z utworzenia pół wypełnionych poziomów donorowych w pobliżu niezajętych pasm przewodnictwa wynikających z defektów struktury krystalicznej, tj. wakansów jodu czy atomów międzywęzłową talu. Wykazano, że w przypadku kryształów rzeczywistych, w szczególności halogenków metali, właściwe uwzględnienie defektów w obliczeniach kwantowo-chemicznych daje możliwość lepszego dopasowania obliczeń teoretycznych do wyników doświadczalnych w porównaniu do obliczeń bazujących na strukturze krystalicznej doskonałej.
Źródło:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej; 2019, 15; 35-56
1897-7421
Pojawia się w:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 19

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies