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Wyszukujesz frazę "electron density distribution" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
A method for the determination of spatial electron density distribution in great Plasma-Focus devices
Autorzy:
Kasperczuk, A.
Paduch, M.
Pisarczyk, T.
Tomaszewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/147148.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
bremsstrahlung radiation
electron density distribution
frame optical camera
plasma-focus device
plasma radiation intensity
shadowgraphy
Opis:
Determination of the electron density of plasma generated in a great plasma-focus device by means of interferometry is very difficult or sometimes impossible. In order to determine spatial electron density distributions of plasma in a PF-1000 device, a special method was prepared, with the use of plasma images obtained by means of both an optical frame camera and shadowgraphy. Analysis of plasma radiation in the very narrow Äë = 60 Ĺ optical range allowed us to determine the relation between intensity of the plasma radiation and the electron density. It was also shown that the influence of electron temperature on plasma radiation is not large. The presented method allowed us to obtain spatial electron density distributions of plasma (in relative units) in the PF-1000 device. By means of this method a number of important information about the plasma-focus phenomenon was obtained.
Źródło:
Nukleonika; 2002, 47, 1; 23-26
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania rozkładu gęstości elektronowej w kryształach, czyli jak zobaczyć szczegóły struktury elektronowej cząsteczek
Electron density distribution in crystals or how to see the details of the electronic structure of molecules
Autorzy:
Kubicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/171566.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
rozkład gęstości elektronowej
model multipolowy
oddziaływania międzycząsteczkowe
pochodne 4-nitroimidazolu
electron density distribution
multipolar model
intermolecular interactions
4-nitroimidazole derivatives
Opis:
X-ray structural analysis might be regarded as a method of visualizing molecules as they appear in the crystals. The model, which is conventionally and universally used in this method, the Independent Atom Model (IAM) assumes that the electron density distribution, which scatters the X-rays is built of the spherically-symmetrical, neutral atoms. This model is responsible for the unprecedented success of X-ray structural analysis, which reflects in about one million crystal structures (i.e. the sets coordinates of the atoms constituting the molecules) deposited in the various databanks (cf. Fig. 1), and in the speed and accuracy which the method has reached. In principle, in few hours one can get the complete information about the crystal structure. But this success is accompanied by negligence of the scientific virtue hidden beyond the IAM. In fact, it was known from the very beginning of the X-ray diffraction studies by von Laue and Braggs, that some fine details of the electron density distribution should be available. The technological advance (four-circle diffractometers, powerful X-ray sources, fast computers etc.) caused that in 1960’s the time was ripe for the development of the experimental studies of details of electron density distribution in the crystals, beyond the IAM. The early experiments by Coppens and co-workers proved that this information – about the electron density transferred to the covalent bonds, lone pairs, even intermolecular interactions – can actually be obtained and analyzed (Fig. 2). The need for the model which could be used in the least-squares procedure led to the formulation of so-called pseudoatom models, including the most popular till now, Hansen-Coppens model (eq. 2) in which the aspherical part is described in terms of real spherical harmonics. In this paper, the basics of the electron density studies is described in some detail, including the step-by-step description of a typical procedure from the experiment to the final steps of refinement. An example of the analysis of the high-resolution structure of 1,2-dimethyl-4-nitro-5-morpholine-imidazole hydrate is used to show an application of this method in studying the intermolecular interactions, including weak C-H···O and C-H···N hydrogen bonds. It is shown that the multipolar model is able to deliver more informations than the promolecular model with spherically symmetrical electron distributions.
Źródło:
Wiadomości Chemiczne; 2014, 68, 5-6; 403-427
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coronal Electron Density Distribution Estimated from Meter Type II Radio Bursts and Coronal Mass Ejections
Autorzy:
Yusof, N. S.
Hamidi, Z. S.
Norsham, N. A.
Jafni, A. I.
Kahlid, N. M.
Hamdan, M. N.
Kamaruddin, Farahana
Tahar, Muhammad Redzuan
Monstein, C.
Shariff, N. N. M.
Powiązania:
https://bibliotekanauki.pl/articles/1192681.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
coronal mass ejection
Type II radio burst
electron density distribution
e-CALLISTO
Opis:
In this paper, we investigate the characteristic coronal mass ejection and Type II radio burst, we calculated the drift rate of Type II Radio burst and determined the electron density distribution from a Coronal Mass Ejections. The data were taken from website e-CALLISTO, Space Weather, SolarHam and also from the Langkawi National Observatory, National Space Agency, Langkawi Kedah, Malaysia. All the data collected on 15th March 2015, 4th November 2015 and 16th December 2015. On 16 March 2015, the events were associated with slower C9 solar flare and CME. For this week, the events were causing radio blackouts on Earth. On 4 November 2015, the events were associated with M1.9 solar flare, CME and Solar burst Type II. The value of the solar wind was 570.4 km/Sec and value for radio sun was 124 sfu. For drift rate, we calculated the value for sites in Sri Lanka (ACCIMT-SRI), Ooty, India (OOTY), Indonesia (INDONESIA) and Kasi, South Korea (KASI) at between 0324 to 0328 UTC. In South Korea was highest drift rate, which is 1.397 MHz/s. Also, at HB9SCT, Switzerland (HB9SCT), Humain, Belgium (Humain), Daro, Germany (Daro-VHF) and TCD in Birr, Ireland (BIR), we calculated the drift rate of solar burst Type II between 1200 until 1203 UTC. In Belgium had the highest value of the drift rate to compare at other sites. Harmonic pattern was also appeared for all these sites. On 16th December 2015, this event associated with C6.6 solar flare and CME. These events give an impact on the earth geomagnetic field which is formed of aurora because of the combination of both events that trigger geomagnetic storming.
Źródło:
World Scientific News; 2016, 46; 19-35
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Xe and Kr bonding abilities in the single crystal oxygen vacancies of the uranium based fuel
Autorzy:
Dąbrowski, L.
Szuta, M.
Powiązania:
https://bibliotekanauki.pl/articles/147880.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
noble gases
chemical bond
UO2 single crystal
valence electron density distribution
atomic force constants
bond energy
crystal lattice
Opis:
The valence electron density distribution of krypton and xenon located in the oxygen vacancy and in its nearest neighbourhood was performed by application of the method “ab initio”. The results are presented on the graphs. The bonding energies of krypton and xenon in the uranium dioxide crystal lattice were calculated. It was found also that krypton and xenon cause a local increase of UO1.75Xe0.25 and UO1.75Kr0.25 unit cell and cause its deformation what is presented in tables. The force constants of krypton and xenon were also assigned what gives evidence about the strong bond of krypton and xenon with the UO1.75Xe0.25 and UO1.75Kr0.25 single crystal lattice. Obtained results are compared with the analogical studies of He atom incorporation into UO2 single crystal lattice.
Źródło:
Nukleonika; 2012, 57, 1; 95-100
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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