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81.
Adriaan Peeters Kris Coolsaet Gunnar Brinkmann Nicolas Van Cleemput Veerle Fack 《Journal of mathematical chemistry》2009,45(2):471-477
GrInvIn (Graph Invariant Investigator) is a software framework for teaching graph theory and for research in graph theory and graph theoretic chemistry.
It enables users to construct graphs, compute invariants (e.g. topological indices in chemistry) and investigate relations
between these concepts. The design of GrInvIn emphasizes easy usage and makes use of software engineering techniques that
enable the user to easily extend the system (e.g. by adding new topological indices to investigate). 相似文献
82.
We discuss how measurements of fluctuations in the absorption of cosmic microwave background photons by neutral gas at redshifts z approximately 7-200 could reveal the primordial deuterium abundance of the Universe. The strength of the cross-correlation of brightness-temperature fluctuations in the redshifted 21-cm line of hydrogen with those in the redshifted 92-cm line of deuterium is proportional to the value of the deuterium-to-hydrogen ratio [D/H] fixed during big bang nucleosynthesis. Although challenging, this measurement would provide the cleanest possible determination of [D/H], free from contamination by structure formation processes at lower redshifts. We additionally report our result for the thermal spin-change cross section in deuterium-hydrogen scattering. 相似文献
83.
Sergei Fomin Kris Kilpatrick Richard Hubbard 《Applied mathematics and computation》2010,216(7):2169-2176
Rimming flow of a non-Newtonian fluid on the inner surface of a horizontal rotating cylinder is investigated. Simple lubrication theory is applied since the Reynolds number is small and liquid film is thin. For the steady-state flow of a power-law fluid the mathematical model reduces to a simple algebraic equation regarding the thickness of the liquid film. The qualitative analysis of this equation is carried out and the existence of two possible solutions is rigorously proved. Based on this qualitative analysis, different regimes of the rimming flow are defined and analyzed analytically. For the particular case, when the flow index in a power-law constitutive equation is equal to 1/2, the problem reduces to the fourth order algebraic equation which is solved analytically by Ferrari method. 相似文献
84.
I. V. Bagrov I. M. Belousova A. V. Ermakov V. M. Kiselev I. M. Kislyakov T. K. Kris’ko T. D. Murav’eva 《Optics and Spectroscopy》2008,105(5):720-725
The stability of the optical properties and the generation efficiency of singlet oxygen of a solidphase photosensitizer based on fullerene in an aqueous suspension subjected to prolonged intense irradiation with visible light are studied in comparison with a photosensitizer based on methylene blue in an aqueous solution. Changes in the absorption spectra show that, as a result of 20-min irradiation, the content of fullerene decreases by 2% from its initial value, while that of methylene blue decreases by 19%. In both cases, the dynamics of the decrease in the photosensitizing ability of the photosensitizers in the course of their irradiation correlates with the changes in their spectra, but the magnitude of this decrease in the case of the solid-phase photosensitizer is greater than the magnitude of its spectral changes because of the surface nature of the photosensitization process. The study of the absorption spectra of fullerene coatings shows that their irradiation in water or in air causes the same photodegradation of fullerene. At the same time, studies with the help of the electron spin resonance (ESR) technique reveal differences in the nature of processes undergone by fullerene in water and in air. 相似文献
85.
Cross-coupling of sinapyl p-hydroxybenzoate and sinapyl alcohol produces an 8-8-cross-coupled product that is also detected in lignifying poplar tissues, implicating sinapyl p-hydroxybenzoate as a lignin precursor. 相似文献
86.
O. V. Kris’ko V. M. Silonov T. V. Skorobogatova D. P. Bokarev 《Moscow University Physics Bulletin》2007,62(6):377-382
An expression for the characteristic function of a nonlocal smooth model potential of an elementary metal is obtained in terms of the full nonlocal theory. The magnesium phonon spectra calculated using the expressions for a characteristic function agree satisfactorily with the experimental data. 相似文献
87.
Kris Driesen Jeroen Beeckman Christiane Görller-Walrand 《Journal of luminescence》2007,127(2):611-615
Switching of near-infrared emission was observed for liquid crystal (LC) cells filled with a chiral nematic liquid-crystal mixture (mixture of E7 and cholesteryl nonanoate) doped with luminescent neodymium(III) or ytterbium(III) β-diketonate complexes. The operating principle of the LC cell is based on an electrically induced phase transition from a chiral nematic to a nematic phase. The chiral nematic phase scatters the excitation light more strongly, resulting in more efficient light absorption and intenser photoluminescence. 相似文献
88.
89.
From an elementary observation, we derive some upper bounds for the number of mutually opposite points in the classical generalized polygons having 3 points on each line. In particular, it follows that the Ree-Tits generalized octagon O(2) of order (2, 4) has no ovoids. Also, we deduce from another observation a similar upper bound in any generalized hexagon of order (s, s
3). 相似文献
90.
Moringa oleifera (M. oleifera) leaves are rich in nutrients and antioxidant compounds that can be consumed to prevent and overcome malnutrition. The water infusion of its leaf is the easiest way to prepare the herbal drink. So far, no information is available on the antioxidant, antimutagenic, and antivirus capacities of this infusion. This study aimed to determine the composition of the bioactive compounds in M. oleifera leaf infusion, measuring for antioxidant and antimutagenic activity, and evaluating any ability to inhibit the SARS-CoV-2 main protease (Mpro). The first two objectives were carried out in vitro. The third objective was carried out in silico. The phytochemical analysis of M. oleifera leaf infusion was carried out using liquid chromatography-mass spectrometry (LC-MS). Antioxidant activity was measured as a factor of the presence of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The antimutagenicity of M. oleifera leaf powder infusion was measured using the plasmid pBR322 (treated free radical). The interaction between bioactive compounds and Mpro of SARS-CoV-2 was analyzed via molecular docking. The totals of phenolic compound and flavonoid compound from M. oleifera leaf infusion were 1.780 ± 5.00 µg gallic acid equivalent/g (µg GAE/g) and 322.91 ± 0.98 µg quercetin equivalent/g (µg QE/g), respectively. The five main bioactive compounds involved in the infusion were detected by LC-MS. Three of these were flavonoid glucosides, namely quercetin 3-O-glucoside, kaempferol 3-O-neohesperidoside, and kaempferol 3-α-L-dirhamnosyl-(1→4)-β-D-glucopyranoside. The other two compounds were undulatoside A, which belongs to chromone-derived flavonoids, and gentiatibetine, which belongs to alkaloids. The antioxidant activity of M. oleifera leaf infusion was IC50 8.19 ± 0.005 µg/mL, which is stronger than the standard butylated hydroxytoluene (BHT) IC50 11.60 ± 0.30 µg/mL. The infusion has an antimutagenic effect and therefore protects against deoxyribonucleic acid (DNA) damage. In silico studies showed that the five main bioactive compounds have an antiviral capacity. There were strong energy bonds between Mpro molecules and gentiatibetine, quercetin, undulatoside A, kaempferol 3-o-neohesperidoside, and quercetin 3-O-glucoside. Their binding energy values are −5.1, −7.5, −7.7, −5.7, and −8.2 kcal/mol, respectively. Their antioxidant activity, ability to maintain DNA integrity, and antimutagenic properties were more potent than the positive controls. It can be concluded that leaf infusion of M. oleifera does provide a promising herbal drink with good antioxidant, antimutagenic, and antivirus capacities. 相似文献