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    Wyświetlanie 1-14 z 14
    Tytuł:
    Prediction of the Crystalline Densities of Aliphatic Nitrates by Quantum Chemistry Methods
    Autorzy:
    Wang, Guixiang
    Xu, Yimin
    Xue, Chuang
    Ding, Zhiyuan
    Liu, Yan
    Liu, Hui
    Gong, Xuedong
    Powiązania:
    https://bibliotekanauki.pl/articles/358531.pdf
    Data publikacji:
    2019
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    aliphatic nitrate
    density
    quantum chemistry
    correlation
    Opis:
    Crystal density is a basic and important parameter for predicting the detonation performance of explosives, and nitrate esters are a type of compound widely used in the military context. In this study, thirty-one aliphatic nitrates were investigated using the density functional theory method (B3LYP) in combination with six basis sets (3-21G, 6-31G, 6-31G*, 6-31G**, 6-311G* and 6-31+G**) and the semiempirical molecular orbital method (PM3). Based on the geometric optimizations at various theoretical levels, the molecular volumes and densities were calculated. Compared with the available experimental data, the densities calculated by various methods are all overestimated, and the errors of the PM3 and B3LYP/3-21G methods are larger than those of other methods. Considering the results and the computer resources required by the calculations, the B3LYP/6-31G* method is recommended for predicting the crystalline densities of organic nitrates using a fitting equation. The results obtained with this method are slightly better than those reported by Keshavarz and Rice. In addition, the effects of various groups (such as –ONO2, –OH, –Cl, –O–, and –CH2–) on the densities are also discussed, which is helpful for the design of new molecules in terms of practical requirements.
    Źródło:
    Central European Journal of Energetic Materials; 2019, 16, 3; 412-432
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Counterion effects on the alkali dissolution mechanism of quartz
    Autorzy:
    Yao, Yu-yun
    Tang, Yun
    Yang, Yong
    Li, Guo-hui
    Wu, Bo
    Dai, Wen-zhi
    Powiązania:
    https://bibliotekanauki.pl/articles/2200337.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    quartz
    counterion
    quantum chemistry
    hydrolysis
    mechanism
    Opis:
    In gold ore, quartz plays an important role in mineral formation by acting as the follower. Understanding counterion release, transport, and deposition in alkali solution is a prerequisite for evaluating the potential role of gold separate from quartz deposits in pretreatment. In this work, the aggregation, retention, and release of counterion in alkali solution media were investigated by kinetic research and pure mineral experiments, the correlation and mechanism of these processes were revealed by combining geochemical theory, interaction energy calculation, and quantum chemistry. The results showed that the retention and release of counterion were closely related to the dissolution and corrosion rate of quartz. The NH4+ and Fe2+ with higher mineral affinity reduced the quartz stability, and the dispersion stability and mobility of the quartz were greatly improved by an alkaline substance due to the enhancement of steric hindrance effects. Quantum chemical calculation results show that ammonium ion promotes the dissolution of quartz stronger than ferrous ion, which is mainly reflected in reducing the activation energy required for the formation of transition state (TS1), which can be verified by kinetic calculation. These findings provide essential insight into the extraction of gold coated by quartz as well as a vital reference for the experiment of gold-loaded quartz leaching in mineral processing.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2023, 59, 1; art. no. 160038
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structure and separation quality of various N- and O-donor ligands from quantum-chemical calculations
    Autorzy:
    Trumm, M.
    Schimmelpfennig, B.
    Geist, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/148110.pdf
    Data publikacji:
    2015
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    actinide chemistry
    extracting ligands
    lanthanide chemistry
    quantum chemistry
    separation factor
    Opis:
    Although BTP (2,6-di(1,2,4-triazin-3-yl)pyridine) has been proven to be a highly effective N-donor ligand for the selective An(III)/Ln(III) separation, the origin of its selectivity is still under discussion. We present in this paper quantum-chemical calculations at the density functional theory (DFT) and MP2 level which highlight the role of the aquo ions in the separation process. Furthermore these data will be the reference for future force-field development to investigate the differences in An(III) complexation reactions compared to their Ln(III) counterparts.
    Źródło:
    Nukleonika; 2015, 60, No. 4, part 2; 847-851
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Program package MP-ZAVA for parallel quantum-chemical computing in the spd-basis
    Autorzy:
    Berzigiyarov, P. K.
    Zayets, V. A.
    Razumov, V. F.
    Sheka, E. F.
    Powiązania:
    https://bibliotekanauki.pl/articles/1965900.pdf
    Data publikacji:
    2001
    Wydawca:
    Politechnika Gdańska
    Tematy:
    quantum chemistry
    parallel codes
    semiempirical approach
    spd-basis
    Opis:
    A parallel realization of the NDDO-WF technique for semi-empirical quantum-chemical calculations on large molecular systems in the spd-basis is described. The technological aspects of designing scalable parallel calculations on super computers (by using MPI library) are discussed. The scaling of individual algorithms and entire package was carried out for two model systems with a number of atomic orbitals of 894 and 2014, respectively. The speedup was determined in computer experiments with the RM600 E60 and Cluster Intel PIII multi-processor systems. The effect of communication rate on the package performance is discussed.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 3; 271-300
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Degradation mechanism study of amine collectors in Fenton process by quantitative structure-activity relationship analysis
    Autorzy:
    Wang, X.
    Liu, W.
    Duan, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/110363.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    amine collectors
    Fenton process
    QSAR
    degradation mechanism
    quantum chemistry
    Opis:
    In this study, advanced oxidation processes (AOPs), Fenton process, was applied to degrade ten amine collectors. The experimental results indicated that most of the tested amines could be removed rapidly and effectively at pH=4, while the degradation of quaternary ammonium compounds was less than others. To research the Fenton oxidation process, the degradation-rate constants of amine collectors were calculated by the pseudo-second order kinetic model, then which was used as the dependent variable to establish a quantitative structure activity relationship (QSAR) model. Meanwhile, 16 molecular structure descriptors and quantum mechanical parameters for amine collectors were simulated and analyzed by using Materials Studio software. The optimum QSAR model was established based on the partial least squares regression (PLS) method and confirmed by the statistics analysis. The model revealed that hydrogen bond acceptor (HBA) and the maximum values of electrophilic attack in C atom sites (f(-)c) were the major effect factors for the degradation-rate constants of amine collector.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 3; 713-721
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Quantum Chemical Study of Aminonitrocyclopentanes as Possible High Energy Density Materials (HEDMs)
    Autorzy:
    Bai, J.
    Chi, W. J.
    Li, L. L.
    Yan, T.
    Wen, X. E.
    Li, B. T.
    Wu, H. S.
    Ma, F. L.
    Powiązania:
    https://bibliotekanauki.pl/articles/358101.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    cyclopentane derivatives
    high energy density materials
    impact sensitivity
    quantum chemistry
    DFT
    available free space
    Opis:
    Nitro and amine groups were introduced into the cyclopentane skeleton, and the heats of formation, detonation performance, bond dissociation energies, and impact sensitivity for these aminonitrocyclopentanes were calculated in detail at the B3LYP/6-311G** level. The results show that all of the derivatives have negative heats of formation, which are influenced by the position of the substituent groups. Their stabilities were estimated and analyzed according to their bond dissociation energies and calculated characteristic H50 values. Most of the compounds were found to have a lower impact sensitivity than HMX. Furthermore, the detonation velocities and detonation pressures were predicted via the Kamlet-Jacobs equation. Of all these aminonitrocyclopentanes, E has the best detonation properties (ρ = 2.05 g/cm3, D = 9.11 m/s, P = 39.62 GPa) and can be considered as a candidate high energy density material.
    Źródło:
    Central European Journal of Energetic Materials; 2013, 10, 4; 467-480
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nowe spojrzenie na efekt podstawnikowy
    A new look at the substituent effect
    Autorzy:
    Szatyłowicz, H.
    Krygowski, T. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/171716.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    efekt podstawnikowy
    stałe Hammetta
    metody chemii kwantowej
    substituent effect
    Hammett constants
    quantum chemistry modeling
    Opis:
    Classical view on the substituent effect (SE) is associated with an empiric approach presented 80-years ago by Hammett [1]. He proposed a simple formula to represent the effect of a substituent upon the rate or equilibrium constants of a reaction in which the reacting group is in a side chain attached to the ring and introduced quantitative descriptors of the SE named substituent constants σ, defined in terms of dissociation constants of meta- and para- substituted benzoic acids. Then the Hammett’s equation relied on using them to describe SE for various physicochemical properties, P(X), by means of linear regression like P(X)=ρ·σ, where ρ is so called reaction constants describing sensitivity of a system in question on the SE. Application of the quantum chemistry modeling allowed to find descriptors (independent of empirical approaches) which are characterized by clear physical meaning and are accessible by use of standard computational packages. The oldest descriptor is based on homodesmotic reaction [X-R-Y + R = R-X + R-Y] in which energy of products is subtracted from that of substrates [32]. The model is named as SESE (substituent effect stabilization energy) and its values are usually well correlated with empirical constants σ, or their modifications. Ten years ago Sadlej-Sosnowska introduced [23, 24] an effective descriptor of SE based on atomic charges of a substituent X and the ipso carbon atom named cSAR(X) (charge of the substituent active region). Unlike atomic charges at substituent, q(X), the cSAR(X) values correlate well with the Hammett substituent constants [25]. Recently as an interesting and showing new aspects descriptor of SE appeared a model making use of population of electrons at sigma and pi orbitals of planar pi-electron systems (or their fragments), named as sEDA and pEDA [33]. Again in particular cases these descriptors correlate with the Hammett σ. This descriptor allowed to reveal how strong is SE on population of pi-electron systems in substituted derivatives of benzene, and how much is this different for para and meta substituted species. Analysis of the relation of pEDA vs sEDA for meta and para substituted derivatives of nitrobenzene revealed that sEDA values increase with a decrease of electronegativity of the linking atom [47]. The above mentioned action of the sigma structure is modulated by the remaining part of the substituent as well as its pi-electron structure. This part of substituents (including also the linking atom) is responsible for an interplay of the sigma structure with the pi-electron one. Application of cSAR(X) for series of meta- and para- substituted phenol and phenolate derivatives [36] revealed that reverse substituent effect, i.e. the effect of impact of the functional group Y on the electron accepting/donating power of the substituent in systems like X-R-Y may be as large as the overall differences in these kind of properties between NO and NMe2! In the σ constants scale this is full range of σ for uncharged substituents, 1.73 units of σ. Application of cSAR for CH2 groups in 1-X-bicyclo[2.2.2]octane derivatives and using the regression of cSAR(CH2) against cSAR(X) values allowed to document that substituent effect in these systems is inductive in nature [39]. In summary, substituent effect descriptors based on quantum chemistry modeling are usually consistent with the empirical ones, but are able to present more detailed information on physical aspects of the problem.
    Źródło:
    Wiadomości Chemiczne; 2017, 71, 7-8; 497-516
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ab initio investigation of ethanoltetracene interactions during adsorption
    Badanie ab initio oddziaływania etanol-tetracen podczas adsorpcji
    Autorzy:
    Kania, S.
    Kościelniak-Mucha, B.
    Kuliński, J.
    Słoma, P.
    Wojciechowski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/296408.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Łódzka. Wydawnictwo Politechniki Łódzkiej
    Tematy:
    noncovalent interactions
    adsorption energy
    quantum chemistry calculations
    interakcje niekowalencyjne
    energia adsorpcji
    obliczenia z chemii kwantowej
    Opis:
    Ab initio calculations presented in this work are performed to investigate the geometry, interaction energy and bonding properties of binary complexes formed between neutral ethanol and tetracene molecules. Two different geometries were applied for the study. The interaction energies between molecules in the complex posses minimum at the distance of about 3.6 Å among oxygen atom in ethanol and the neighbouring carbon atom of tetracene skeleton.
    Obliczenia kwantowo chemiczne potwierdziły istnienie warstwy adsorpcyjnej etanolu w odległości d ok. 3,6 Å od narożnego węgla w bocznym pierścieniu szkieletu tetracenu. Warstwa ta zapewnia jedynie zachodzenie procesu fizykosorpcji. Ponieważ badania doświadczalne wykazały wzrost skrośnego prądu płynącego przez warstwę tetracenu podczas procesu aktywacji tej warstwy w wyniku oddziaływania z parami etanolu, to musi tu jeszcze zachodzić proces związany z transferem elektronów. Proces taki jest procesem chemisorpcji. Uzyskane wartości energii orbitali LUMO dla kompleksu złożonego z cząsteczki tetracenu i etanolu wskazują że w przypadku, gdy wymiana elektronów zachodzi pomiędzy cząsteczką etanolu leżącą w płaszczyźnie szkieletu tetracenu a cząsteczką tetracenu to związane jest to z przejściem pomiędzy poziomami LUMO+3 i LUMO+4 kompleksu. Jeżeli jednak wymiana elektronu zachodzi podczas przemieszczanie się etanolu w płaszczyźnie odległej o ok. 3,3 Å od płaszczyzny szkieletu tetracenowego ponad środkiem bocznego pierścienia benzenowego szkieletu tetracenu to wówczas wymiana elektronu pomiędzy cząsteczką etanolu a cząsteczką tetracenu zachodzi przy przejściu pomiędzy poziomami LUMO+2 i LUMO+3 kompleksu.
    Źródło:
    Scientific Bulletin. Physics / Technical University of Łódź; 2018, 39; 13-25
    1505-1013
    2449-982X
    Pojawia się w:
    Scientific Bulletin. Physics / Technical University of Łódź
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    NANOPACK: parallel codes for semiempirical quantum-chemical calculations of large systems in the sp- and spd-basis
    Autorzy:
    Berzigiyarov, P. K.
    Zayets, V. A.
    Ginzburg, I. Ya.
    Razumov, V. F.
    Sheka, E. F.
    Powiązania:
    https://bibliotekanauki.pl/articles/1963005.pdf
    Data publikacji:
    2002
    Wydawca:
    Politechnika Gdańska
    Tematy:
    quantum chemistry
    NANOPACK parallel codes
    semiempirical NDDO and NDDO-WF approaches
    sp- and spd-basis
    Opis:
    A parallel implementation of the conventionally used NDDO (MNDO, AM1, PM3, CLUSTER-Z1) and modified NDDO-WF (CLUSTER-Z2) techniques for semiempirical quantum-chemical calculations on large molecular systems in the sp- and spd-basis, respectively, is described. The atom-pair distribution of data over processors forms the basis of the parallelization. The technological aspects of designing scalable parallel calculations on supercomputers (by using ScaLAPACK and MPI libraries) are discussed. The scaling of individual algorithms and entire package was carried out for model systems with 894, 1920, and 2014 atomic orbitals. The package speedup provided by different multi-processor systems involving a cluster of the Intel PIII processors, Alpha-21264-processor-built machine MBC-1000M, and CRAY-T3E, is analyzed. The effect of computer characteristics on the package performance is discussed.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 2; 233-251
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sprzętowa implementacja funkcji orbitalnej na potrzeby obliczeń kwantowo-chemicznych
    Hardware implementation of the atom orbital calculation
    Autorzy:
    Wielgosz, M.
    Jamro, E.
    Russek, P.
    Wiatr, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/154619.pdf
    Data publikacji:
    2010
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    akceleracja sprzętowa
    komputery dużej mocy (HPC)
    FPGA
    obliczenia zmiennoprzecinkowe
    funkcja exp()
    High Performance Reconfigurable Computing
    quantum chemistry
    custom computing
    HPC
    Opis:
    W niniejszym artykule przedstawione zostały wyniki implementacji modułu obliczającego wartość orbitalu atomowego w punkcie. Moduł ten stanowił cześć składową jednostki generującej wartość potencjału korelacyjno-wymiennego, wykorzystywaną w obliczeniach kwantowo-chemicznych. Prezentowana jednostka składa się z potokowych bloków zmiennoprzecinkowych. W pracy zaprezentowano również wyniki akceleracji obliczeń względem procesora ogólnego przeznaczenia Itanium2 1.6 GHz.
    The paper presents FPGA acceleration and implementation results of the orbital function calculation employed in quantum-chemistry. The orbital function core is composed of the authors' customized floating-point hardware modules. These modules are scalable from single to double precision, capable of working at frequency ranging from 100 to 200 MHz. Besides hardware implementation, the design process also involved reformulation of the algorithm in order to adapt them to the platform profile. The computational procedure presented in this paper is part of the algorithm for generating exchange-correlation potential, and is also recognized as one of the most computationally intensive routines. This feature justifies the effort devoted to develop its hardware implementation. The precision of floating-point operations becomes a primary concern when dealing with low-level quantum chemistry procedures, thus the authors have taken various measures to optimize them, both in terms of resource consumption and processing speed.
    Źródło:
    Pomiary Automatyka Kontrola; 2010, R. 56, nr 7, 7; 705-707
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    O zależnościach pomiędzy aromatycznością i efektem podstawnikowym w układach jednopierścieniowych
    On relation between substituent effect and aromaticity in monocyclic systems
    Autorzy:
    Szatyłowicz, Halina
    Krygowski, Tadeusz Marek
    Powiązania:
    https://bibliotekanauki.pl/articles/171709.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    aromatyczność
    HOMA
    NICS
    efekt podstawnikowy
    stałe Hammetta
    metody chemii kwantowej
    aromaticity
    harmonic oscillator model of aromaticity
    nucleus independent chemical shift
    substituent effect
    Hammett constants
    quantum chemistry modeling
    Opis:
    Aromaticity/aromatic and substituent/substituent effects belong to the most commonly used terms in organic chemistry and related fields. They are used for more than a century, and so far are the subject of thousands publications a year. The quantitative description of the aromaticity of planar π-electron cyclic molecules is based on four criteria: (i) they are more stable than their acyclic unsaturated analogues, (ii) bonds have intermediate lengths between those for the single and double ones, (iii) external magnetic field induces π-electron ring current, and (iv) aromatic systems prefer reactions in which the π-electron structure is preserved. conserved. Quantitative characteristics based on these criteria, named as aromaticity indices, allow to relate aromaticity to the substituent effect. This latter can be described using either traditional Hammett-type substituent constants or characteristics based on quantum-chemistry. For this purpose, the energies of properly designed homodesmotic reactions and electron density distribution are used. In the first case, a descriptor named SESE (substituent effect stabilization energy) is obtained, while in the second case – cSAR (charge of the substituent active region), which is the sum of the charge of the ipso carbon atom and the charge of the substituent. The application of these substituent effect descriptors to a set of π-electron systems, such as: benzene, quinones, cyclopenta- and cyclohepta-dienes, as well as some azoles, allowed to draw the following conclusions: (i) The less aromatic the system, the stronger the substituent influences the π-electron system. Highly aromatic systems are resistant to the substituent effect, in line with the organic chemistry experience that aromatic compounds dislike reactions leading to changes in the π-electron structure of the ring. (ii) Intramolecular charge transfer (resonance effect) is privileged in cases where the number of bonds between the electron-attracting and electron-donating atoms is even. These effects are much weaker when this number is odd. Classically, it may be related to traditional para vs meta substituent effects in benzene derivatives. We should note that in electron-accepting groups, such as CN or NO2 (and others), electron-accepting atoms are second counting from Cipso. (iii) In all cases, when the substituent changes number of π-electrons in the ring in the direction of 4N+2, its aromaticity increases, for example electron-donating substituents in exocyclic substituted pentafulvene, or a halogen atom in complexes with heptafulvene.
    Źródło:
    Wiadomości Chemiczne; 2019, 73, 3-4; 243-261
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Tert-butyl esters of 2,3-diaryl-3-arylaminopropanoic acids – stereoselective synthesis, isolation, spectroscopic and structural elucidation
    Autorzy:
    Tasheva, D. N.
    Zareva, S. Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/778823.pdf
    Data publikacji:
    2011
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    tert-butylowego estrów kwasów 2,3-diarylowe-3-arylaminopropanoic
    właściwości optyczne
    chemia kwantowa
    tert-butyl esters of 2,3-diaryl-3-arylaminopropanoic acids
    optical properties
    quantum chemistry
    Opis:
    A series of seven substituted tert-butyl esters of 2,3-diaryl-3-arylaminopropanoic acids has been synthesized, isolated, spectroscopically and structurally elucidated. An influence of the substituents on the spectroscopic characteristics and conformations is discussed using the data of the linear-polarized IR- (IR-LD), UV-spectroscopy and 1H-NMR. Theoretical quantum chemical calculations are carried out, with a view to explaining and supporting the experimental optical properties and the electronic structure. The stereoselective synthesis of the corresponding diastereoisomers is optimized, thus giving good yields (62–72%) and purity of the compounds.
    Źródło:
    Polish Journal of Chemical Technology; 2011, 13, 3; 12-17
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Digital Chemistry
    Autorzy:
    Kurić, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/411924.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    digital chemistry
    chemical compounds
    codes in chemistry
    code speed of light
    quantum physics
    Opis:
    The subjects of our research are program lawfulness, cybernetic lawfulness, and informational lawfulness in molecule sequence in the nature. In the science, one question has been present for a long time, that is, if there is one unique common connection that links all phenomena in the cosmos. The doubt is, if the periodical in the biochemical process is only a physical-chemical matter of objective material relationship or maybe a matter of numbers and mathematics. With the goal to find the answers on some of those questions, we have made a decision to do a research on, if in the nature exists such one unique mathematical array and one mathematical lawfulness which could be valid for all phenomena in chemistry and physics.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 14, 2; 168-178
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The concepts of an atom and chemical bond in physics and chemistry: the role of approximations
    Autorzy:
    Koleżyński, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/429151.pdf
    Data publikacji:
    2011
    Wydawca:
    Uniwersytet Papieski Jana Pawła II w Krakowie
    Tematy:
    philosophy of chemistry
    the concept of atom
    the concept of chemical bond
    evolution of meaning
    quantum mechanics
    Opis:
    It is well known from the history of science, that almost all crucial concepts are subject to change during the evolution of scientific theories. There is, however, another (often forgotten or omitted) aspect of this process, i.e. a role of some approximations, necessarily applied to any system of interest, in practically every single calculation carried out within quantum mechanical formalism, which can also result in change of the meaning of some of these concepts. In this paper, the two concepts of great importance in chemistry and physics, namely the concept of an atom, and the concept of a chemical bond are analyzed, both from the point of view of classical chemistry and quantum mechanics. The evolution of their meaning, due to the approximations, resulting in some important differences is highlighted.
    Źródło:
    Semina Scientiarum; 2011, 10
    1644-3365
    Pojawia się w:
    Semina Scientiarum
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-14 z 14

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