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排序方式: 共有328条查询结果,搜索用时 31 毫秒
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The synthesis of ditryptophan-pyridine conjugates and their binding to mercury ions is described. Conjugate 3 shows an excellent ability to sequester mercury from solution and rescue bacterial growth in a concentration-dependent survival assay. It is proposed that such compounds, composed primarily of bioessential/biodegradable components, could be potentially used as sequestrating agents for the removal of Hg(II) ions in detoxification strategies. 相似文献
324.
Byoungseon Jeon Changhyun Ko Adri C.T. van Duin Shriram Ramanathan 《Surface science》2012,606(3-4):516-522
Compositional stability of various vanadium oxides and oxide growth on vanadium surfaces have been studied using reactive molecular dynamics simulation methods. Vanadium dioxide (VO2), sesquioxide (V2O3), pentoxide (V2O5), and hexavanadium tridecaoxide (V6O13) are studied in bulk crystalline and thin film structures, investigating charge distribution and pair distribution functions of particle interactions. The stability is estimated to be pentoxide, hexavanadium tridecaoxide, sesquioxide, and dioxide respectively in decreasing order in thin film structures. We then analyze oxide growth kinetics on vanadium (100) and (110) surfaces. The oxidation rate, stoichiometry, charge distribution, and the effect of surface orientation on kinetic phenomena are noted. In the early stages of surface oxidation of our simulation configurations, sesquioxide is found to be the dominant component. The modeling and simulation results are compared with experiments where available. 相似文献
325.
Hwang J Shields VB Thomas CI Shivaraman S Hao D Kim M Woll AR Tompa GS Spencer MG 《Journal of Crystal Growth》2010,312(21):3219-3224
Epitaxial, graphitic carbon thin films were directly grown on C-face/(0 0 0 1¯) SiC and (0 0 0 1) sapphire by chemical vapor deposition (CVD), using propane as a carbon source and without any catalytic metal on the substrate surface. Raman spectroscopy shows the signature of multilayer graphene/graphite growth on both the SiC and sapphire. Raman 2D-peaks have Lorentzian lineshapes with FWHM of ∼60 cm−1 and the ratio of the D-peak to G-peak intensity (ID/IG) linearly decreases (down to 0.06) as growth temperature is increased. The epitaxial relationship between film and substrates were determined by X-ray diffraction. On both substrates, graphitic layers are oriented parallel to the substrate, but exhibit significant rotational disorder about the surface normal, and predominantly rhombohedral stacking. Film thicknesses were determined to be a function of growth time, growth temperature, and propane flow rate. 相似文献
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Dr. Bathini Veeraprakash Dr. Gallelli Pratap Dr. Nitin P. Lobo Prof. Krishna V. Ramanathan Dr. Tanneru Narasimhaswamy 《Chemphyschem》2023,24(12):e202300074
Structurally simple rod-like π-conjugated mesogens with thiophene directly connected to phenyl, biphenyl, and fluorenone rings with terminal chains are synthesized respectively. The occurrence of smectic A/smectic C phases is concurred by a hot-stage optical polarising microscope (HOPM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The static 1D and 2D 13C nuclear magnetic resonance (NMR) studies in the liquid crystalline phase are carried out to find the alignment-induced chemical shifts (AIS) and 13C−1H dipolar couplings. The orientational order parameters of the mesogens determined from 13C−1H dipolar couplings disclose that the long axis is not only collinear to the C3−C4 bond of the thiophene ring but also for the local axes of phenyl and biphenyl rings. For fluorenone-based mesogen, the molecular biaxiality is found to be high owing to the increased breadth of the molecule. The study unveils that the orientation of thiophene and the phenyl rings is similar in the current mesogens in stark contrast to mesogens, where thiophene is connected to phenyl rings through linking groups. 相似文献
328.
Quantum wave packet dynamics of the Li(2S)+HCl( ) reaction in its electronic ground state is studied. The initial state-selected and energy-resolved dynamical attributes such as reaction probability, integral cross section, and thermal rate constant for the Cl-abstraction and H-abstraction pathways are reported. All partial wave contributions of J up to 120 were found to be necessary for the title reaction up to the collision energy of ∼1.0 eV. The dynamical results reveal that the Cl-abstraction is more favored over the H-abstraction for the different rovibrational (v, j) excitations. Due to the existence of an early barrier in the potential energy surface, the cross sections increase with increasing collision energy. The rate constants also monotonously increase with temperature for both channels. Resonances are identified and characterized in terms of eigenfunctions and lifetimes. Nearly 120 well-resolved eigenstates are reported for the LiHCl complex, and they are categorized as van der Waals (vdW), barrier and product states according to the nodal progressions along (R, r, γ). The vdW resonances reveal a local-mode behavior of quasibound type at low energies and extended progressions at high energies. Further, the single-quantized periodic orbit type is also observed in the barrier region, which decays very fast. Finally, the lifetime analysis reveals that the vdW resonances can survive as long as ∼2.2 ps, which is much longer than the lifetime of the resonances in the barrier region. 相似文献