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The relative energies of one-, two-, and three-dimensional Bravais lattice Lennard-Jones particles can be calculated by lattice sums. The expression of lattice sums over a Lennard-Jones potential can be manipulated into a form that converges rapidly. A formalism capable of calculating the lattice potential at arbitrary points of a completely general lattice has been developed. This method provides an alternative way to calculate the relative energies from the surface and the interior bulk sites of many chemical systems. The method is illustrated with application to hcp and fcc Lennard-Jonesium, both for the relative binding energy and for calculating the potential along the geometric diffusion pathway between tetrahedral and octahedral interstitial sites. Diffusion from the tetrahedral site to the octahedral site experiences a barrier of 752.600 in units of 4 epsilon. The reverse pathway experiences a barrier of 1035.614 in units of 4 epsilon. 相似文献
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K. Srinivasa Rao Y. Lingappa M. Ravi Prakash Reddy T.L. Prakash 《Phase Transitions》2013,86(3):235-243
In this study, we successfully synthesized single-phase hexagonal closed packed (HCP) and face-centered cubic (FCC) nickel nanoparticles via reduction of nickel nitrate hexahydrate and nickel acetate tetrahydrate, respectively, in polyethylene glycol-200. Structural information of the as-synthesized nickel nanoparticles are studied by X-ray diffraction (XRD) as a function of the molar concentration of the nickel precursor. XRD results reveal that low concentrations of nickel precursor (0.005?M and below) favor the HCP, while high concentrations favor the mixture of HCP and FCC crystal structures. Particle size of HCP structure is found in the range of ~15?nm via transmission electron microscope analysis. Vibratory sample magnetometer is employed to study its magnetic behavior and the results reveal that FCC crystalline phase shows ferromagnetic nature with high saturation magnetization (M s?~?39.6?emu?gm?1) as compared to metastable HCP crystalline structure (M s?~?2?emu?gm?1). The surfactants bonding on the surface of nickel nanoparticles are studied. 相似文献
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The Thomas–Fermi approximation gives the Grüneisen parameter γ=γ∞=1/2 for all materials at extreme compression (P→∞ or V→0). After re-analyzing the existing experimental data of volume dependence of Grüneisen parameter γ of hexagonal close-packed (HCP) iron, we find that γ=1/2+a(V/V 0)1/3+b(V/V 0) n , where a, b and n are constants. Based on this new form of γ, the second Grüneisen parameter q, the Debye temperature θD and the shear sound velocity v s of HCP iron are discussed in the present work. It is found that the zero pressure second Grüneisen parameter q 0=0.654, which is consistent with the previously determined value of HCP iron for Earth's core physics from Dubrovinsky et al. The calculations for the Debye temperature and the shear sound velocity are also found to be in good agreement with the experimental data. 相似文献
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AbstractAn important part in the research of separation of various compound classes is the study of relationship between structure and property by describing the effect of structure on compounds’ chromatographic retention. The aim of this work was to study the chromatographic retention of the firstly synthesized benzimidazoles from water-acetonitrile and water-methanol solutions on hypercrosslinked polystyrene (HCP) by high-performance liquid chromatography (HPLC). The effect of water-methanol and water-acetonitrile solutions’ composition on the benzimidazole derivative retention factors on HCP was studied. The thermodynamic characteristics of sorption of benzimidazoles’ transition from water-organic solutions onto the surface of HCP phase were obtained. The thermodynamic compensation effects were studied. It has been shown that the benzimidazole nitro derivative realizes additional specific interactions with the aromatic network of HCP. The slope ratio of the Soczewiński–Wachtmeister equation was calculated. It was shown that 1-hydroxymethylbenzimidazole and 2-aminobenzimidazole characterized by small volumes and containing hydrophilic substituents do not subordinate Soczewiński–Wachtmeister model under ranging from 75 to 85% concentrations of acetonitrile. 相似文献
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T. Sakurai X.-D. Wang Q.K. Xue Y. Hasegawa T. Hashizume H. Shinohara 《Progress in Surface Science》1996,51(4):263-408
Scanning tunneling microscopy investigations of adsorption and film growth of various fullerenes on semiconductor and metal surfaces are reviewed. The fullerenes being studied are C60, C70, C84, Sc@C82 and Y@C82 and the substrates being used for adsorption are Si (111), Si (100), Ge (111), GaAs (110), GaAs (001), Au (111), Au (110), Au (100), Cu (111) and Ag (111) surfaces. 相似文献
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Ab initio calculations using a variety of basis sets and including electron correlation via the MP3 method are reported for HCP and FCP and their positive ions. Comparisons are made with the available experimental data.N.F.C.R Postgraduate Student. 相似文献
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Kevin Clark Natalia B. Pigni Kithmini Wijesiri Jos A. Gascn 《Molecules (Basel, Switzerland)》2021,26(9)
The increased interest in sequencing cyanobacterial genomes has allowed the identification of new homologs to both the N-terminal domain (NTD) and C-terminal domain (CTD) of the Orange Carotenoid Protein (OCP). The N-terminal domain homologs are known as Helical Carotenoid Proteins (HCPs). Although some of these paralogs have been reported to act as singlet oxygen quenchers, their distinct functional roles remain unclear. One of these paralogs (HCP2) exclusively binds canthaxanthin (CAN) and its crystal structure has been recently characterized. Its absorption spectrum is significantly red-shifted, in comparison to the protein in solution, due to a dimerization where the two carotenoids are closely placed, favoring an electronic coupling interaction. Both the crystal and solution spectra are red-shifted by more than 50 nm when compared to canthaxanthin in solution. Using molecular dynamics (MD) and quantum mechanical/molecular mechanical (QM/MM) studies of HCP2, we aim to simulate these shifts as well as obtain insight into the environmental and coupling effects of carotenoid–protein interactions. 相似文献
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Characterization of a biopharmaceutical protein and evaluation of its purification process using automated capillary Western blot 下载免费PDF全文
This paper describes the application of an automated size‐based capillary Western blot system (Sally instrument) from ProteinSimple, Inc., for biopharmaceutical fusion‐Fc protein characterization and evaluation of its purification process. The fusion‐Fc protein column purification from an excess of single chain Fc polypeptide and removal of an enzyme coexpressed for protein maturation have been demonstrated using an automated capillary Western system. The clearance of a selected host cell protein (HCP) present in cell culture of fusion‐Fc protein was also quantitatively monitored throughout the protein purification process. Additionally, the low levels of fusion‐Fc product‐related impurities detected by traditional slab gel Western blot were confirmed by the automated capillary Western system. Compared to the manual approach, the automated capillary Western blot provides the advantages of ease of operation, higher sample throughput, greater linearity range, and higher precision for protein quantitation. 相似文献
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ABSTRACTWe studied the first Brillouin zone of the hexagonal close-packed (HCP) structure and the improved ones of the modified analytical embedded atom method (EAM) potentials were adopted to calculate the properties of the mono- and bi-vacancies and the phonon dispersions for HCP transition metals Ru, Sc, Ti, Y, and Zr. The agreements with the experimental data showed that the improved potentials for the HCP transition metals are available. 相似文献