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Tytuł:
The Beam Current Considerations in SEM Accordance to Mirror Effect Phenomenon
Autorzy:
Al-Obaidi, H. N.
Khaleel, I. H.
Powiązania:
https://bibliotekanauki.pl/articles/411880.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
scanning electron microscope
Electron Beam Current
Electron Mirror Images
Opis:
A theoretical investigation have been presented to exploring the influence of electrons beam current on the electron mirror image deduced inside the scanning electron microscope (SEM). A rough mathematical expression for the electric potential that associated with electron beam is derived. The results clearly shows that the beam current could be used to enhance or conversely deteriorate the phenomena of mirror effect. So this work procedure may consider to be tool controllable of this phenomena for investigation purposes.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 10, 1; 70-75
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The suitability of scanning electron microscopy in the evaluation of bone structure surfaces and selection of alloplastic materials for facial skeletal reconstruction
Autorzy:
Job, Katarzyna
Składzień, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1397288.pdf
Data publikacji:
2021
Wydawca:
Index Copernicus International
Tematy:
hydroxyapatite
scanning electron microscope
secondary electron detection
Opis:
Introduction: Functional and aesthetic problems can arise even from small losses created in the facial skeleton. Injuries and oncological surgeries are the most frequent causes of these losses within the facial skeleton. Advances in surgical interventions have allowed for ever-increasing degrees of resections, increasing oncological radicality as well as treatment effectiveness, providing the patient with the chance for a longer life. However, this subsequently requires the use of even more advanced reconstruction techniques in order to restore quality of life and comfort to the patient, as well as enable their return to professional and social activities. The necessity of reconstructive surgery applies not only to patients with cancer, but also to patients with impaired or failing sensory and organ function as a result of inflammatory conditions, injuries, or non-oncological surgeries. There are many available reconstruction procedures, which depend on the location of the loss, the type of tissue lost, the degree of loss and patient-dependent factors. Materials used in reconstruction surgeries may include the patients’ tissues when available, and artificial reconstruction materials otherwise. Material and methods: The analysis involved fragments of bone tissue removed during surgery. Due to the nature of the medical procedure and the inability to replant the tissue, it was regarded as medical waste. The preparations used were observed under an optical microscope and an electron scanning microscope, and a chemical analysis was performed. The chemical composition of samples was analysed using a low vacuum detector (LVD) at an accelerating voltage of 15 kV and 10 kV and at a spot size of 4 and 3.5. The observations were performed in a secondary electron (SE) detection system. Results: Observation of parameters under an optical microscope and of images obtained using an electron scanning microscope showed the presence of typical, compact bone tissue with varied surface shapes in each case (various degrees of unevenness and porosity). Chemical composition analysis confirmed the presence of compounds from the CaO-P2O5-H20 system. The Ca/P (calcium/phosphorus) ratio obtained from the chemical analysis varied from 1.33 to 2.1, and indicated a varied morphology of calcium phosphates forming the bone structures of the facial skeleton. Conclusions: 1. Calcium phosphates are characterised by excellent biocompatibility because of their chemical affinity to bone, and are ideal for the reconstruction of bone losses within the facial skeleton. 2. Biodegradable polymers have the highest functional potential among several groups of biomaterials used in tissue engineering because of their ability to be tailored individually, in addition to their high biocompatibility.
Źródło:
Polish Journal of Otolaryngology; 2021, 75, 4; 14-19
0030-6657
2300-8423
Pojawia się w:
Polish Journal of Otolaryngology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Advanced microstructure diagnostics and interface analysis of modern materials by high-resolution analytical transmission electron microscopy
Autorzy:
Neumann, W.
Kirmse, H.
Hausler, I.
Mogilatenko, A.
Zheng, C.
Hetaba, W.
Powiązania:
https://bibliotekanauki.pl/articles/199872.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electron microscopy
energy dispersive X-ray spectroscopy
electron energy loss spectroscopy
electron holography
Opis:
Transmission electron microscopy (TEM) is a powerful diagnostic tool for the determination of structure/property relationships of materials. A comprehensive analysis of materials requires a combined use of a variety of complementary electron microscopical techniques of imaging, diffraction and spectroscopy at an atomic level of magnitude. The possibilities and limitations of quantitative TEM analysis will be demonstrated for interface studies of the following materials and materials systems: Nickel-based superalloy CMSX-10, (Zn,Cd)O/ZnO/Al2O3, (Al,Ga)N/AlN/Al2O3, GaN/LiAlO2 and FeCo-based nanocrystalline alloys.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 2; 237-253
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of the basic photon and electron dosimetry data for Neptun 10PC linear accelerators
Autorzy:
Shokrani, P.
Monadi, S.
Powiązania:
https://bibliotekanauki.pl/articles/147666.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dosimetry
photon beam
electron beam
linear electron accelerator
Opis:
. In recent years the similarity of dosimetric characteristics of modern linear accelerators with the same make, model and nominal energy, has become more common. The goal of this study was to quantitatively investigate the reproducibility of the basic photon and electron dosimetry data from Neptun 10PC accelerators across the institutions. In the current study, the photon and electron dosimetry data collected during acceptance and initial commissioning of six Neptun 10PC linear accelerators are analyzed. The dates of original installations of these six machines were evenly spread out over a 5 year period and the series of measurements were conducted during an average of 1-2 months after original installations. All units had identical energies and beam modifiers. For photon beams, the collected data include depth dose data, output factors and beam profile data in water. For electron beams, in addition to depth dose data and output factors, the effective source skin distance for 10 × 10 cm field size is also presented. For most beam parameters the variation (one standard deviation), was less than 1.0% (less than 2% for 2 parameters). A variation of this magnitude is expected to be observed during annual calibration of well-maintained accelerators. In conclusion, this study is presenting a consistent set of data for Neptun 10PC linear accelerators. This consistency implies that for this model, a standard data set of basic photon and electron dosimetry could be established, as a guide for future commissioning, beam modeling and quality assurance purposes.
Źródło:
Nukleonika; 2008, 53, 4; 181-185
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The IOERT IntraLine accelerator : the development, current state, and future plans
Autorzy:
Adrich, P.
Hanke, R.
Kulczycka, E.
Kosiński, K.
Meglicki, B.
Misiarz, A.
Pławski, E.
Staszczak, M.
Swat, K.
Syntfeld-Każuch, A.
Wójtowicz, M.
Wysocka-Rabin, A.
Powiązania:
https://bibliotekanauki.pl/articles/148309.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radiotherapy
mobile electron accelerator
intraoperative electron radiation therapy (IOERT)
Opis:
Intraoperative electron radiation therapy (IOERT) is a cancer treatment method that combines oncologic surgery with electron beam radiotherapy. This method can reduce the duration of entire tumor treatment and increase its effectiveness. Moreover, shortening the treatment time signifi cantly reduces the cost and accessibility of the therapy. As a result of interdisciplinary research, an innovative accelerator for IOERT, the IntraLine, was developed. In the course of this work, four patent applications were fi led. Today, the work is half way through. In the near future, the device will be optimized. New mechanical design solutions will be developed. Mechanical optimization will signifi cantly reduce the weight of the device. Accelerators control system, which today is in the demo phase, will also be signifi cantly upgraded. This paper describes the stages of the IntraLine accelerator development, its current state and plans for the future R&D work, within the scope of our new Intra-Dose project.
Źródło:
Nukleonika; 2016, 61, 1; 3-9
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single-electron transport characteristics in quantum dot arrays due to ionized dopants
Autorzy:
Moraru, D.
Ligowski, M.
Tarido, J. C.
Miki, S.
Nakamura, R.
Yokoi, K.
Mizuno, T.
Tabe, M.
Powiązania:
https://bibliotekanauki.pl/articles/384277.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
single dopant
silicon nanowire
single-electron transport
single-electron transfer
Opis:
Single charge manipulation for useful electronic functionalities has become an exciting and fast-paced direction of research in recent years. In structures with dimensions below about 100 nm, the physics governing the device operation turn out to be strikingly different than in the case of larger devices. The presence of even a single charge may completely suppress current flow due to the basic electronelectron repulsion (so called Coulomb blockade effect) [1]. It is even more exciting to control this effect at the level of single-electron/single-atom interaction. The atomic entity can be one donor present in silicon lattice with a Coulombic potential well. In principle, it can accommodate basically a single electron. We study the electrical behavior of nanoscale-channel silicon-on-insulator field-effect transistors (SOI-FETs) that contain a discrete arrangement of donors. The donors can be utilized as "stepping stones" for the transfer of single charges. This ability opens the doors to a rich world of applications based on the simple interplay of single charges and single atoms, while still utilizing mostly conventional and well established fabrication techniques. In this work, we distinguish the effects of single-electron transport mediated by one or few dopants only. Furthermore, we show how the single-electron/single-donor interaction can be tuned by using the external biases. We demonstrate then by simulation and experiment the feasibility of single-electron/bit transfer operation (single-electron turnstile).
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 4; 52-54
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deformation Mechanisms and Fracture of Ni-Based Metallic Glasses
Autorzy:
Lesz, S.
Griner, S.
Nowosielski, R.
Powiązania:
https://bibliotekanauki.pl/articles/353790.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metals
transmission electron microscopy
scanning electron microscopy
fracture
shear bands
Opis:
The cracking of materials and fracture surface is of great practical and academic importance. Over the last few years the development of the fractography of crystalline alloys resulted in a useful tool for the prediction or failure analysis. Many attempts have been made to observe cracks using optical microscopy, X-ray topography and transmission electron microscopy (TEM). Of these techniques, the resolution of optical microscopy and X-ray topography is too poor. By contrast, the resolution of TEM is high enough for detailed information to be obtained. However, in order to apply TEM observations, a thin foil specimen must be prepared, and it is usually extremely difficult to prepare such a specimen from a pre-selected region containing a crack. In the present work, deformation mechanisms fracture surfaces of Ni-based metallic glass samples have been studied by specially designed experiments. In order to study the deformation mechanisms and fracture the Ni-based metallic glasses have been investigated in the tensile test. The structure and fracture surfaces after the decohesion process in tensile tests were observed using transmission electron microscope (TEM) and scanning electron microscope (SEM), respectively. The studies of structure were performed on thin foils. Moreover the investigated tape was subjected to a banding test. Then, the tape was straightened and the thin foil from the area of maximum strain was prepared. This thin foil sample was deformed before the TEM investigation to obtain local tears.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 791-796
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Quenching Rate on the Structure and Magnetic Properties of the Fe-Based Amorphous Alloy
Autorzy:
Nabiałek, M.
Powiązania:
https://bibliotekanauki.pl/articles/350944.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transmissions electron microscopy
scanning electron microscopy
amorphous matrials
free volumes
quasidislocation
Opis:
This paper presents the results of investigations into the structure, microstructure and magnetic properties of Fe61Co10Y8W1B20 amorphous alloy. The alloy samples were in two physical forms: (1) plates of approximate thickness 0.5 mm (so-called bulk amorphous alloys) and (2) a ribbon of approximate thickness 35 μm (so-called classic amorphous alloy). The investigations comprised: X-ray diffractometry, Mössbauer spectrometry, transmission electron microscopy, and selected magnetic measurements; all of the investigations were carried out on samples in the as-quenched state. Analysis of the obtained SEM and TEM images, X-ray diffraction patterns, Mössbauer spectrometry results and measurements of the magnetisation in a high magnetic field facilitated collectively the detailed description of the structure of the investigated alloy, which was found to depend on the quenching speed.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 439-444
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design Study on Electron Energy Spread Effect on Performance of Linac Irradiation Facility with the Aid of Electron Energy Spectrum Online Analyzer
Autorzy:
Bułka, S.
Zimek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2055250.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radiation sterilization
electron accelerator
electron energy
depth dose distribution
computer modelling
Opis:
Ongoing energy measurement is one of the parameters such as: electron beam current, transporter speed, or scanning width, that must be recorded according to the conditions imposed in the accelerator validation procedure. Described measurement method based on the use of a secondary electron collecting electrode has been tested at the electron beam linear accelerator installation typically used for radiation sterilization. Data processing and presentation of the electron beam characteristics is based on the information obtained via dedicated pulse acquisition interface. The energy spectra parameters provide data for modeling and calculation of dose distribution for irradiation process optimization and also knowledge of accelerator RF alignment in case of service.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 1; 103--108
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Milling Time on Amorphization of Mg-Zn-Ca Powders Synthesized by Mechanical Alloying Technique
Autorzy:
Lesz, S.
Kremzer, M.
Gołombek, K.
Nowosielski, R.
Powiązania:
https://bibliotekanauki.pl/articles/354717.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Mg-based powders
transmission electron microscopy
scanning electron microscopy
mechanical alloying
Opis:
Mg60 Zn35 Ca5 amorphous powder alloys were synthesized by mechanical alloying (MA) technique. The results of the influence of high-energy ball-milling time on amorphization of the Mg60 Zn35 Ca5 elemental blend (intended for biomedical application) were presented in the study. The amorphization process was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM). Initial elemental powders were mechanically alloyed in a Spex 8000 high-energy ball mill at different milling times (from 3 to 24 h). Observation of the powder morphology after various stages of milling leads to the conclusion that with the increase of the milling time the size of the powder particles as well as the degree of aggregation change. The partially amorphous powders were obtained in the Mg60 Zn35 Ca5 alloy after milling for 13-18h. The results indicate that this technique is a powerful process for preparing Mg60 Zn35 Ca5 alloys with amorphous and nanocrystalline structure.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 845-851
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Secondary electron interactions in materials with environmental and radiological interest
Autorzy:
García, G.
Blanco, F.
de Pablos, J.
Pérez, J.
Williart, A.
Powiązania:
https://bibliotekanauki.pl/articles/148529.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron scattering
energy deposition
Opis:
Important environmental and radiological applications require energy deposition models including the interactions between the secondary electrons and the atoms or molecules of the medium. In this work we propose a method to obtain reliable cross-section data to be used in these models by combining total and ionisation cross-section measurements with simple calculations of the differential and integral elastic cross sections. The energy loss spectra obtained in this experiment have been also used to derive the stopping power of the considered materials for electrons. Some examples of results for atomic (Xe) and molecular (CF4) targets are presented and discussed in this paper.
Źródło:
Nukleonika; 2003, 48, 2; 103-107
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Post-implantation defects instability under 1 MeV electron irradiation in GaAs
Autorzy:
Warchoł, S.
Rzewuski, H.
Krynicki, J.
Grötzschel, R.
Powiązania:
https://bibliotekanauki.pl/articles/146724.pdf
Data publikacji:
2000
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron annealing
GaAs
implantation
Opis:
The influence of 1 MeV electron irradiation on the stability of post-implantation defects in GaAs has been investigated. The n-type GaAs wafers of <100> orientation were implanted with 150 keV As+ ions below the amorphization threshold at RT using the implantation dose of 2×1013 ions cm–2 at a constant flux of 0.1 žA cm–2. Then the implanted samples were irradiated with a scanned beam of 1 MeV electrons from a Van de Graaff accelerator in a dose range (0.5–5.0)×1017 cm–2 at 320 K. RBS and channeling spectroscopy of 1.7 MeV 4He+ ions were used to determine the depth distribution of defect concentration before and after 1 MeV irradiations. New results of an "oscillatory" behaviour of the damage level as a function of 1 MeV electron fluence are presented.
Źródło:
Nukleonika; 2000, 45, 4; 225-228
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Angular dependence of post-implantation damage recovery under 1 MeV electron irradiation in GaAs
Autorzy:
Warchoł, S.
Rzewuski, H.
Krynicki, J.
Grotzschel, R.
Powiązania:
https://bibliotekanauki.pl/articles/147146.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron annealing
GaAs
implantation
Opis:
The angular dependence of post-implantation defects removal in GaAs irradiated with 1 MeV electrons from a Van de Graaff accelerator has been investigated. The possible way of enhancing defect annealing consists in ionization created by electron irradiation. In this paper new results of a damage level behaviour dependent on 1 MeV electron beam angle irradiation are presented. GaAs single crystals of <100> orientation were implanted with 150 keV As+ ions at RT and then irradiated with a scanning beam of 1 MeV electrons at some selected angles. Rutheford Backscattering Spectroscopy (RBS) of 1.7 MeV 4He+ ions were used to determine the depth distribution of defect concentration before and after electron irradiation. The results relate clearly the ionization intensity created by the electron beam with angle of incidence with respect to the GaAs <100> orientation.
Źródło:
Nukleonika; 2002, 47, 1; 19-21
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Building a new software of electromagnetic lenses (CADTEL)
Autorzy:
Hasan, H.S.
Powiązania:
https://bibliotekanauki.pl/articles/411585.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Electron lenses
Objective and projector properties
Lenses aberrations
Electron optics
Charged particle optics
Software and simulation in electron lenses
Opis:
The Computer Aided designing Tools for Electromagnetic Lenses (CADTEL) is a new software as application package of programs concept to aid both users and professionals in symmetric and asymmetric electromagnetic lenses with single, double, and multipole piece in electron microscope of electron optics field. The CADTEL software has been designed to run on several computer platforms and includes two types of design procedure. The first one named, analysis procedure (which is based on trial and error) where consist of three sorts called; H1 programs for magnetic scalar potential by solving Laplace's equation [1, 2], H2 and H3 programs for magnetic vector potential by solving Poisson's equation [3, 4] in linear and non linear media respectively. While the second part, named H4 programs for the synthesis procedure (inverse design). The previous types differ by the obtaining the magnetic flux density, and poles shape, while it is analog by compute and plot the lens properties which are operating at zero, low, high, and infinite magnification conditions (operation modes). CADTEL software consist of computational and plot steps of magnetic field, equipotential surfaces, flux lines, objective and projector properties, and poles shape for proposed lens design which are appear in auto visual interfaces, that are coded in visual basic language [5].
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 4; 46-55
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron optics column for a new MEMS-type transmission electron microscope
Autorzy:
Krysztof, M.
Grzebyk, T.
Górecka-Drzazga, A.
Adamski, K.
Dziuban, J.
Powiązania:
https://bibliotekanauki.pl/articles/201167.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
MEMS
miniature TEM
electron emission
focusing of electron beam
electron optics column
emisja elektronów
ogniskowanie
wiązka elektronów
mikrostruktura TEM
Opis:
The concept of a miniature transmission electron microscope (TEM) on chip is presented. This idea assumes manufacturing of a silicon-glass multilayer device that contains a miniature electron gun, an electron optics column integrated with a high vacuum micropump, and a sample microchamber with a detector. In this article the field emission cathode, utilizing carbon nanotubes (CNT), and an electron optics column with Einzel lens, made of silicon, are both presented. The elements are assembled with the use of a 3D printed polymer holder and tested in a vacuum chamber. Effective emission and focusing of the electron beam have been achieved. This is the first of many elements of the miniature MEMS (Micro-Electro-Mechanical System) transmission electron microscope that must be tested before the whole working system can be manufactured.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 2; 133-137
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge Density Distribution, Electrostatic Properties and Sensitivity of the Highly Energetic Molecule 2,4,6-Trinitro-1,3,5-triazine: A Theoretical Study
Autorzy:
Srinivasan, P.
Maheshwari, K.
Jothi, M.
Kumaradhas, P.
Powiązania:
https://bibliotekanauki.pl/articles/358320.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
energetic molecule
electron density
Laplacian of electron density
electrostatic potential
impact sensitivity
Opis:
Ab initio and density functional theory (DFT) calculations were carried out on the energetic propellant molecule 2,4,6-trinitro-1,3,5-triazine (TNTA) to understand its bond topology and its energetic properties using the theory of atoms in molecules (AIM). The DFT method predicts that the electron density ρ bcp (r) at the bond critical points of ring C-N bonds is ∼ 2.34 e Å -3 and the corresponding Laplacian ∇ 2 ρ bcp(r) is ∼ -24.4 e Å -5 ; whereas these values are found to be very small in the -NO2 group attached to C-N bonds [ρ bcp(r): ∼ 1.73 e Å -3 and Δ 2 ρ bcp (r): ∼ -14.5 e Å -5 ]. The negative Laplacian values of C-NO 2 bonds are significantly lower which indicates that the charges of these bonds are highly depleted. The C-NO2 bonds exhibit low bond order (∼ 0.8), as well as low (∼ 56.4 kcal/mol) bond dissociation energy. As we reported in our earlier studies, we found high bond charge depletion for these bonds, which are considered the weakest bonds in the molecule. The frontier orbital energies exhibit a wide band gap, which is larger than those of existing molecules TATB, TNT and TNB. The impact sensitivity (H 50 %) (4.2 m) and oxygen balance (2.77%) were calculated and compared with related structures. Large negative electrostatic potential regions were found near the nitro groups where reaction is expected to occur. The relation between charge depletion ∇ 2 ρ bcp(r) and the electrostatic potential at the bond midpoints V mid reveals the sensitive areas of the molecule.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 1; 59-76
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal Density Prediction, Charge Density Distribution and the Explosive Properties of the Highly Energetic Molecule 2-Methyl-5-nitramino-tetrazole: a DFT and AIM Study
Autorzy:
Srinivasan, P.
Kumaradhas, P.
Powiązania:
https://bibliotekanauki.pl/articles/358115.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
crystal density
electron density
Laplacian of electron density
impact sensitivity
electrostatic potential
Opis:
The ab initio crystal density, bond topological and explosive properties of the energetic molecule 2-methyl-5-nitraminotetrazole (MNAT) have been calculated by the MOLPAK/PMIN software and the AIM theory. The density predicted from the crystal structure simulation almost matches the experimental density. The geometrical parameters of the molecule lifted from the crystal structure are in very close agreement with the reported X-ray molecular structure. The bond topological analysis predicts a signifcantly low bond electron density, as well as a less Laplacian of electron density, for the N–NO2 bond. The Laplacian for the bond to the attached methyl group, the C(2)–N(2) bond, is also found to be less negative; the less negative values of the Laplacian confrms that these are the weakest bonds in the molecule. The impact sensitivity (h50) of the molecule has been calculated, and is almost equal to the reported experimental value. The sensitivity of the molecule was also estimated from the electrostatic imbalance parameter and has the value ν = 0.242. The isosurface of the electrostatic potential of the molecule displays a high negative electrostatic potential region around the tetrazole ring and the nitramine N–N bond, which are the possible reactive locations in the molecule.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 1; 53-68
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microscopic analysis of the nanostructures impact on endothelial cells
Autorzy:
Kołodziejczyk, Agnieszka Maria
Kucińska, Magdalena
Jakubowska, Aleksandra
Siatkowska, Małgorzata
Sokołowska, Paulina
Kotarba, Sylwia
Makowski, Krzysztof
Komorowski, Piotr
Walkowiak, Bogdan
Powiązania:
https://bibliotekanauki.pl/articles/1844983.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
nanostructures
atomic force microscopy
transmission electron microscopy
scanning electron microscopy
cell morphology
Opis:
Nowadays nanostructures are more and more often designed as carriers for drug delivery, especially to improve the drug pharmacokinetics and pharmaco-dynamics. Numerous kinds of nanostructures are considered a good prospect for medical applications thanks to their small size, acceptable biocompatibility and toxicity. Due to the fact that nanotechnology is a new field of science, every nano-scale product must be thoroughly examined regarding its toxicity to the human body. This study provides new insights into effects of exposing endothelial cells to the selected nanostructures. Dendrimers of the fourth generation (PAMAMs), multi-walled carbon nanotubes (MWCNTs) and silver nanoparticles (SNPs) were used to evaluate nanostructures influence on endothelial cells in vitro. The nanostructures were evaluated via transmission electron microscopy and dynamic light scattering technique. The cells previously exposed to the nanostructures were observed and analyzed via the atomic force microscopy and scanning electron microscopy to obtain a quantitative evaluation of the cells morphology. The presence of multi-walled carbon nanotubes and silver nanoparticles on the cells surface was confirmed by the scanning electron microscopy. Our results confirm that the surface association and/or uptake of nanostructures by the cells resulting from physicochemical and biological processes, affect the cells morphology. Morphological changes can be induced by the membrane proteins interaction with nanomaterials, which trigger a sequence of intracel-lular biological processes.
Źródło:
Engineering of Biomaterials; 2020, 23, 154; 2-8
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microscopic analysis of the nanostructures impact on endothelial cells
Autorzy:
Kołodziejczyk, Agnieszka Maria
Kucińska, Magdalena
Jakubowska, Aleksandra
Siatkowska, Małgorzata
Sokołowska, Paulina
Kotarba, Sylwia
Makowski, Krzysztof
Komorowski, Piotr
Walkowiak, Bogdan
Powiązania:
https://bibliotekanauki.pl/articles/970974.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
nanostructures
atomic force microscopy
transmission electron microscopy
scanning electron microscopy
cell morphology
Opis:
Nowadays nanostructures are more and more often designed as carriers for drug delivery, especially to improve the drug pharmacokinetics and pharmaco-dynamics. Numerous kinds of nanostructures are considered a good prospect for medical applications thanks to their small size, acceptable biocompatibility and toxicity. Due to the fact that nanotechnology is a new field of science, every nano-scale product must be thoroughly examined regarding its toxicity to the human body. This study provides new insights into effects of exposing endothelial cells to the selected nanostructures. Dendrimers of the fourth generation (PAMAMs), multi-walled carbon nanotubes (MWCNTs) and silver nanoparticles (SNPs) were used to evaluate nanostructures influence on endothelial cells in vitro. The nanostructures were evaluated via transmission electron microscopy and dynamic light scattering technique. The cells previously exposed to the nanostructures were observed and analyzed via the atomic force microscopy and scanning electron microscopy to obtain a quantitative evaluation of the cells morphology. The presence of multi-walled carbon nanotubes and silver nanoparticles on the cells surface was confirmed by the scanning electron microscopy. Our results confirm that the surface association and/or uptake of nanostructures by the cells resulting from physicochemical and biological processes, affect the cells morphology. Morphological changes can be induced by the membrane proteins interaction with nanomaterials, which trigger a sequence of intracel-lular biological processes.
Źródło:
Engineering of Biomaterials; 2020, 23, 154; 2-8
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties of Ni-Fe-Cu-P-B alloy produced by two component melt spinning (TCMS)
Autorzy:
Wojciechowska, M.
Ziewiec, K.
Kąc, S.
Prusik, K.
Powiązania:
https://bibliotekanauki.pl/articles/351728.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metallic glasses
scanning electron microscopy (SEM)
nanoindentation
transmission electron microscopy TEM
mechanical properties
Opis:
The aim of this work was to investigate the microstructure and mechanical properties of the two-component melt-spun (TCMS) alloy produced from Ni40Fe40B20 and Ni70Cu10P20 melts. The Ni40Fe40B20, Ni70Cu10P20, Ni55 Fe20 Cu5 P10 B10 alloys were arc-melted. Then the alloys were melt-spun in the two different ways i.e.: by casting from a single-chamber crucible and from the two-chamber crucible. All of the above mentioned alloys were processed in the first way and the Ni40Fe40B20 and Ni70Cu10P20 were simultaneously cast on the copper roller from the two-chamber crucible. The microstructure of the alloy was studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) and light microscopy. The mechanical properties were investigated using tensile testing and nanoindentation. The two-component melt-spun (TCMS) amorphous Ni55 Fe20 Cu5 P10 B10 alloy present hardness, tensile strength and Young modulus on the significantly higher level than for a single phase amorphous Ni55 Fe20 Cu5 P10 B10 alloy and slightly below the corresponding values for the Ni40Fe40B20.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 1; 137-140
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Somatic embryogenesis of a tree fern Cyathea delgadii Sternb.: achievements and prospects
Autorzy:
Mikula, A.
Grzyb, M.
Pozoga, M.
Tomiczak, K.
Domzalska, L.
Rybczynski, J.J.
Powiązania:
https://bibliotekanauki.pl/articles/951310.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
somatic embryogenesis
tree fern
Cyathea delgadii
electron microscope
transmissiom electron microscope
scanning electron microscope
zygotic embryogenesis
symplasmic communication
fluorochrome
confocal microscopy
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2015, 96, 1
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specific heat of selected graphites used in calorimetry of electron beam and its influence on the accuracy of measurement of large dose
Autorzy:
Panta, P.
Głuszewski, W.
Powiązania:
https://bibliotekanauki.pl/articles/147858.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radiation processing
radiation sterilization
electron beam (EB)
high dose calorimetry
calibration
electron energy
Opis:
Calorimetry is applicable to both absolute calibration of routine dosimeters and absolute measurements of electron beam (EB) intensity (for industrial radiation processing). Advantages of graphite as the absorbing calorimetric material are a good heat capacity and negligible heat defect of this material. Knowledge of the specific heat capacities of the calorimetric core materials is fundamental in making absolute dose measurements. Two kinds of high-purity graphite used in calorimeters were analysed, i.e. Union Carbide grade AGOT and nuclear grade graphite [10]. There are some differences of specific heat of these graphites, up to 2% , which influence dosimetric response of calorimeters made of them.
Źródło:
Nukleonika; 2005, 50,suppl.2; 55-57
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation and vizualization of the cells grown on ceramic coating by electron microscopy techniques
Autorzy:
Karbowniczek, J.
Gruszczyński, A.
Kruk, A
Czyrska-Filemonowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/285222.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
biocompatibility
biomaterials
scanning electron microscopy
Źródło:
Engineering of Biomaterials; 2017, 20, no. 143 spec. iss.; 37
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of magnetic field measurement in a scanning electron microscope using a microcantilever magnetometer
Autorzy:
Orłowska, Karolina
Mognaschi, Maria E.
Kwoka, Krzysztof
Piasecki, Tomasz
Kunicki, Piotr
Sierakowski, Andrzej
Majstrzyk, Wojciech
Podgórni, Arkadiusz
Pruchnik, Bartosz
di Barba, Paolo
Gotszalk, Teodor
Powiązania:
https://bibliotekanauki.pl/articles/220725.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
scanning electron microscope
magnetometry
microcantilever
Opis:
Scanning electron microscopy (SEM) is a perfect technique for micro-/nano-object imaging [1] and movement measurement [2, 3] both in high and environmental vacuum conditions and at various temperatures ranging from elevated to low temperatures. In our view, the magnetic field expanding from the pole-piece makes it possible to characterize the behaviour of electromagnetic micro- and nano-electromechanical systems (MEMS/NEMS) in which the deflection of the movable part is controlled by the electromagnetic force. What must be determined, however, is the magnetic field expanding from the e-beam column, which is a function of many factors, like working distance (WD), magnification and position of the device in relation to the e-beam column. There are only a few experimental methods for determination of the magnetic field in a scanning electron microscope. In this paper we present a method of the magnetic field determination under the scanning electron column by application of a silicon cantilever magnetometer. The micro-cantilever magnetometer is a silicon micro-fabricated MEMS electromagnetic device integrating a current loop of lithographically defined dimensions. Its stiffness can be calibrated with a precision of 5% by the method described by Majstrzyk et al. [4]. The deflection of the magnetometer cantilever is measured with a scanning electron microscope and thus, through knowing the bias current, it is possible to determine the magnetic field generated by the e-beam column in a defined position and at a defined magnification.
Źródło:
Metrology and Measurement Systems; 2020, 27, 1; 141-149
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radiation processing of polymers and semiconductors at the Institute of Nuclear Chemistry and Technology
Autorzy:
Zimek, Z.
Przybytniak, G.
Kałuska, I.
Powiązania:
https://bibliotekanauki.pl/articles/146107.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron beam accelerators
radiation processing
Opis:
R&D studies in the field of radiation technology in Poland are mostly concentrated at the Institute of Nuclear Chemistry and Technology (INCT). The results of the INCT works on polymer and semiconductor modification have been implemented in various branches of national economy, particularly in industry and medicine. Radiation technology for polymer modification was implemented in the middle of the 1970-ties. Among others, the processes of irradiation and heat shrinkable products expansion have been developed. The transfer of this technology to Polish industry was performed in the middle of the 1980-ties. The present study aims at the formulation of new PE composites better suited to new generation of heat shrinkable products, for example, a new generation of hot-melt adhesives has been developed to meet specific requirements of customers. Modified polypropylene was used for the production of medical devices sterilized by radiation, especially disposable syringes, to overcome the low radiation resistance of the basic material. Modified polypropylene (PP-M) has been formulated at the INCT to provide material suitable for medical application and radiation sterilization process. Modification of semiconductor devices by EB was applied on an industrial scale since 1978 when the INCT and the LAMINA semiconductor factory successfully adopted that technology to improve specific semiconductor devices. This activity is continued on commercial basis where the INCT facilities served to contract irradiation of certain semiconductor devices according to the manufacturing program of the Polish factory and customers from abroad.
Źródło:
Nukleonika; 2006, 51,suppl.1; 129-132
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
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