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991.
Chen X Fischer S Yi Z Boyko V Terrenoire A Reinhold F Rieger J Li X Men Y 《Langmuir : the ACS journal of surfaces and colloids》2011,27(13):8458-8463
Structural rearrangement in a latex powder during dry sintering at temperatures higher than the minimum film formation temperature was investigated by means of synchrotron small-angle X-ray scattering. Two major effects were identified: (1) Deformation of latex particles leads to a closure of voids between them and an extensive perfectioning of the face centered cubic colloidal crystalline ordering. Such an improvement of the colloidal crystalline structure involves preferential crystal growth along certain crystallographic directions as was evidenced by the measured unmatched relative diffraction intensity distribution of the crystallographic (111) and (220) planes. (2) Interdiffusion of polymeric chains between adjacent particles promotes a nanometer sized aggregation of nonpolymeric materials previously located in the interstices between particles. Size and size distribution of the aggregates at different dry sintering conditions were evaluated by using a model considering spheres dispersed in the system. 相似文献
992.
993.
Li H Yang HK Moon BK Choi BC Jeong JH Jang K Lee HS Yi SS 《Inorganic chemistry》2011,50(24):12522-12530
Lu(6)WO(12) and Lu(6)MoO(12) doped with Eu(3+) ions have been prepared by using a citrate complexation route, followed by calcination at different temperatures. The morphology, structure, and optical and photoluminescence properties of the compounds were studied as a function of calcination temperature. Both compositions undergo transitions from a cubic to a hexagonal phase when the calcination temperature increases. All the compositions have strong absorption of near-UV light and show intense red luminescence under a near-UV excitation, which is related to the transfer of energy from the host lattices to dopant Eu(3+) ions. Density functional theory calculations have also been performed. The calculation reveals that hexagonal Lu(6)WO(12) and Lu(6)MoO(12) are indirect bandgap materials, and the near-UV excitations are due to the electronic transitions from the O-2p orbitals to W-5d and Mo-4d orbitals, respectively. The lattice parameters and bandgap energies of hexagonal Lu(6)WO(12) and Lu(6)MoO(12) were determined. 相似文献
994.
The nucleoside-based antiviral phosphoramidates and H-phosphonates were synthesized and separated using reversed-phase liquid chromatography on bridged ethane hybrid (BEH) C18 column packed with 1.7 μm particles of non-chiral stationary phase. The influences of the composition of mobile phase and column temperature have been investigated to optimize the diastereoisomeric separation. Complete separations of the phosphoramidate and H-phosphonate prodrugs with good resolution (RS = 1.99–2.77) were achieved within a short time (5–9 min). The validation study of the optimized method including linearity, accuracy, repeatability and detection limit has revealed it is better performance versus conventional HPLC method. In addition, HPLC was combined with high resolution electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS), which enabled the exact mass measurement and high sensitivity. Using MS as detection, the limits of detection and limits of quantification of the studied pronucleotide diastereoisomers were determined in the range of several nmol L−1 level. 相似文献
995.
The determinant representation of the gauge transformation operators is establised. In this process, the generalized Wronskian determinant is introduced. As a simple application, the au-thors present a construction of the special T-function obtained firstly by Chau et al. (Commun. Math. Phys., 149(1992), 263), which involves the generalized Wronskian determinant. Also, some properties of this determinant are given. 相似文献
996.
2-D NONSEPARABLE SCALING FUNCTIONINTERPOLATION AND APPROXIMATION 总被引:1,自引:0,他引:1
1 IntroductionWe begin witl1 two fundanlental questious of apprdriation theory Namely given sam-ples of a square iutegrable signal dyadically spaced in tin1e, is it possible to reconstruct thesignal?How close can the original signal be aPprokimated from the knowledge of the samples?There are many dtherent approaches to answer these questiolls. In [81, Wells and Zhoushowed that a wavelet approalmatiou theorem is valid for degree 1wavelet systenis in whichone obtains second-order approximation… 相似文献
997.
A novel high-throughput spectrometer with a wide-slit is presented.In conventional spectrometers,the slit limited the light throughput.Here,the slit is replaced with a much wider one(200μm)to increase throughput.A beam splitter is utilized to construct a dual-path optics to measure both non-dispersed and dispersed light intensity which comes from the wide-slit.While the dispersed light intensity is result of the non-dispersed light convoluted spectrum of the source,the spectrum can be acquired by solving the inverse problem of deconvolution.Experiments show that the reconstructed spectra achieved almost the same resolution measured by traditional spectrometer,while throughput and peak signal-to-noise ratio(PSNR)are improved dramatically. 相似文献
998.
A potentially practical scheme is proposed to realize optical quantum simulation of artificial Abelian gauge field in a scalable architecture consisting of cold atomic ensembles with optical cavities.In the present model,the collective excitations of cold atomic ensembles can be converted to the bosonic modes within the low-excitation limit,where the structure of two-dimension(2D)square plaquette enables the polaritons to move like a charged particle subjected to an external magnetic field.We find that the energy spectrum of this hybrid system exhibits a shape of Hofstadter buttery.Our work provides a different perspective to the quantum simulation of condensed matter and many-body physics in the context of cavity quantum electrodynamics.The experimental feasibility are justified using the existing techniques. 相似文献
999.
CHEN YingYing XIE YongBing YANG Jun CAO HongBin LIU Hui ZHANG Yi 《中国科学:化学(英文版)》2013,56(12):1783-1789
A double layered,one-pot hydrothermal method was adopted in this work to prepare transition metal ions(Fe3+,Ni2+,Cu2+and Co2+)doped TiO2.The morphology and chemical properties of TiO2and the status of metal ions were characterized with XRD,TEM,BET,UV-Vis and XPS analysis.TEM images show that the obtained TiO2was very uniform with an average particle size of 10.4 nm.XPS,TEM and XRD results show that transitional metals were doped onto TiO2in the form of ions.Photocatalytic decomposition of oxalic acid under UV illumination and methylene blue degradation under visible light on these materials were conducted,respectively.The results reveal that Cu2+-TiO2and Co2+-TiO2showed a highest activity under UV and visible light illumination,respectively,and they were both more active than commercial P25 TiO2.With this special design of double layers,the hydrolysis of titanium precursor in the system with water can be easily controlled and metal ions are simply doped.This strategy can be further applied to synthesize metal ion doped TiO2using various metal precursors with controllable amounts,and thus lead to better optimization of highly active photocatalyst. 相似文献
1000.
We study the nonreciprocal properties of transmitted photons in a chiral waveguide quantum electrodynamics (QED) system, including single- and two-photon transmissions and second-order correlations. For the single-photon transmission, the nonreciprocity is induced by the effects of chiral coupling and atomic dissipation in the weak coupling region. It vanishes in the strong coupling regime when the effect of atomic dissipation becomes ignorable. In the case of two-photon transmission, there exist two ways of going through the emitter: independently as plane waves and formation of bound state. Besides the nonreciprocal behavior of plane waves, the bound state that differs in two directions also alters transmission probabilities. In addition, the second-order correlation of transmitted photons depends on the interference between plane wave and bound state. The destructive interference leads to the strong antibunching in the weak coupling region, while the effective formation of bound state leads to the strong bunching in the intermediate coupling region. However, the negligible interactions for left-propagating photons hardly change the statistics of the input coherent state. 相似文献