Zhenrong Sun

Electrosorption of ions from aqueous solutions with carbon nanotubes and nanofibers composite film electrodes

Electrosorption of ions from aqueous solutions with carbon nanotubes and nanofibers (CNTs-CNFs) composite film electrodes has been demonstrated. The large area CNTs-CNFs film was directly grown on Ni plate by low pressure and low temperature thermal chemical vapor deposition. The CNTs-CNFs electrodes have great advantages such as low cost, easy operation, long-term reproducibility, and integrity of monolithic CNTs-CNFs film and current collector. Batch-mode experiments at low voltage (0.4–2V) were conducted in a continuously recycling system to investigate the electrosorption process. Purification of water with good reproducibility was achieved because of optimal pore size distribution of CNTs-CNFs composite films.

Electrosorption of NaCl Solutions with Carbon Nanotubes and Nanofibers Composite Film Electrodes

Electrosorption of ions from aqueous solutions with carbon nanotubes and nanofibers (CNTs-CNFs) composite film electrodes has been demonstrated. The low-cost, large area CNTs-CNFs composite film was directly grown on Ni plate by low-pressure, low-temperature thermal chemical vapor deposition. Successful purification of water with good reproducibility by electrosorption of CNTs-CNFs composite films was achieved because of optimal pore size distribution, which leads to lower electrical double-layer overlapping effect. The electrosorption capacity of CNTs-CNFs composite film electrodes was ∼ 15-65 μmol/g and comparable to carbon aerogels. The ion sorption followed a Langmuir isotherm, indicating monolayer adsorption.

Nanobump arrays fabricated by laser irradiation of polystyrene particle layers on silicon

Two-dimensional (2D) nanobump arrays were fabricated by laser irradiation of a regular lattice of absorptive polystyrene (PS) microspheres on an undoped (100) Si wafer. The experiments were performed with single-pulse 248 nm KrF laser radiation. The structure of the arrays fabricated by this method was characterized by field emission scanning electron microscope and atomic force microscope. The near-field effects under the absorptive particle are studied. The ablation and thermal processes induced by the optical near-field around the particles are investigated. The formation mechanism of nanobumps is discussed.

Formation of long- and short-periodic nanoripples on stainless steel irradiated by femtosecond laser pulses

In this paper, we report the formation of long-periodic (LP) ripples with a period of 530–600 nm and short-periodic (SP) ripples with a period of 260–320 nm on stainless steel irradiated by 800 nm femtosecond laser pulses. The split of LP ripples plays the decisive role in the formation of SP ripples. We further conduct pump-probe experiments and numerical simulations to study the ultrafast dynamics of the formation of surface periodic ripples.

Periodic nanoripples in the surface and subsurface layers in ZnO irradiated by femtosecond laser pulses

We present the formation of periodic ripples in ZnO crystal irradiated by a wavelength-tunable femtosecond laser. The results indicate that in the surface thin layer, the periods change from 0.1 lambda to lambda with laser fluences and pulse numbers, and in the subsurface layer the periods are always lambda/2n, where n is the refractive index. The formation processes and mechanisms are also discussed.

Effects of spontaneous emission-induced coherence on population inversion in a ladder-type atomic system

Spontaneous emission can create coherence in a ladder-type three-level atom with equispaced levels, subject to the condition that the atomic dipole moments are nonorthogonal. We study the effects of this kind of coherence on the steady-state population inversion in the atomic system. We show that the population inversion can be greatly enhanced on one of the optical transitions due to the spontaneous emission-induced coherence. Furthermore, we find, within suitable parameters regions, that such coherence can also lead to unexpected population inversion on both of the optical transitions.

Surface-enhanced Raman spectroscopy investigation on human breast cancer cells.

BackgroundNanoparticles are potentially used for early cancer detection, accurate diagnosis, and cancer treatment.ResultsIn this paper, the breast cancer cells treated with gold colloidal suspension were carefully studied by surface-enhanced Raman scattering (SERS) spectra. Raman spectroscopy combining with high-resolution electron microscope is employed to investigate the interaction of gold nanoparticles (GNPs) with the intracellular components. The TEM images show that the GNPs are taken into the living cells and enveloped into some vesicles named ‘lick up vesicles’ in the cytosol.ConclusionsThe SERS spectra and SERS mapping of cells indicate that the major Raman bands are mostly assigned to the vibration characteristics of proteins, and the C-H in-plane bending mode of the substituted benzene in Phenylalanine is remarkably enhanced. Finally, the interaction mechanisms of the GNPs with the intracellular components are further discussed in detail.

Ionization Energies, Electron Affinities, and Polarization Energies of Organic Molecular Crystals: Quantitative Estimations from a Polarizable Continuum Model (PCM)–Tuned Range-Separated Density Functional Approach

We propose a new methodology for the first-principles description of the electronic properties relevant for charge transport in organic molecular crystals. This methodology, which is based on the combination of a nonempirical, optimally tuned range-separated hybrid functional with the polarizable continuum model, is applied to a series of eight representative molecular semiconductor crystals. We show that it provides ionization energies, electron affinities, and transport gaps in very good agreement with experimental values, as well as with the results of many-body perturbation theory within the GW approximation at a fraction of the computational costs. Hence, this approach represents an easily applicable and computationally efficient tool to estimate the gas-to-crystal phase shifts of the frontier-orbital quasiparticle energies in organic electronic materials.

Construction of halide-bridged tungsten-copper-sulfide double cubanelike clusters from a new precursor [(Tp*WS2)2(μ-S2)].

Treatment of [Et(4)N][Tp*WS(3)] (1) (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) with 2 equiv of AgSCN in MeCN afforded a novel neutral compound [(Tp*WS(2))(2)(μ-S(2))] (2). Reactions of 2 with excess CuX (X = Cl, Br, I) in MeCN and CH(2)Cl(2) or CHCl(3) formed three neutral W/Cu/S clusters [{Tp*W(μ(3)-S)(3)Cu(3)(μ-Cl)}(2)Cu(μ-Cl)(2)(μ(7)-Cl)(MeCN)](2) (3), [{Tp*W(μ(3)-S)(3)Cu(3)}(2)Br(μ-Br)(2)(μ(4)-Br)(MeCN)] (4), and [{Tp*W(μ(3)-S)(3)Cu(3)}(2){Cu(2)(μ-I)(4)(μ(3)-I)(2)}] (5), respectively. On the other hand, treatment of 2 with CuX (X = Cl, Br) in the presence of Et(4)NX (X = Cl, Br) produced two anionic W/Cu/S clusters [Et(4)N][{Tp*W(μ(3)-S)(3)Cu(3)X}(2)(μ-X)(2)(μ(4)-X)] (6: X = Cl; 7 X = Br). Compounds 2-7 were characterized by elemental analysis, IR, UV-vis, (1)H NMR, electrospray ionization (ESI) mass spectra, and single-crystal X-ray crystallography. The dimeric structure of 2 can be viewed as two [Tp*WS(2)] fragments in which two W atoms are connected by one S(2)(2-) dianion. Compounds 3-7 all possess unique halide-bridged double cubanelike frameworks. For 3, two [Tp*W(μ(3)-S)(3)Cu(3)](2+) dications are linked via a μ(7)-Cl(-) bridge, two μ-Cl(-) bridges, and a [Cu(MeCN)(μ-Cl)(2)](+) bridge. For 4, one [Tp*W(μ(3)-S)(3)Cu(3)(MeCN)](2+) dication and one [Tp*W(μ(3)-S)(3)Cu(3)Br](+) cation are linked via a μ(4)-Br(-) and two μ-Br(-) bridges. For 5, the two [Tp*W(μ(3)-S)(3)Cu(3)](2+) dications are bridged by a linear [(μ-I)(2)Cu(μ(3)-I)(2)Cu(μ-I)(2)](4+) species. For 6 and 7, two [Tp*W(μ(3)-S)(3)Cu(3)X](+) cations are linked by a μ(4)-X(-) and two μ-X(-) bridges (X = Cl, Br). In addition, the third-order nonlinear optical (NLO) properties of 2-7 in MeCN/CH(2)Cl(2) were investigated by using femtosecond degenerate four-wave mixing (DFWM) technique.

Raman spectroscopic investigation on the interaction of malignanthepatocytes with doxorubicin

Raman spectroscopy has proven to be a very powerful technique and is currently experiencing a renaissance. In this paper, it is used to explore the interaction between doxorubicin and malignant hepatocytes in vitro. For the addition of doxorubicin, the band intensity at 1609 cm-1, mainly assigned to C=C in-plane bending mode of phenylalanine and/or tyrosine residues, increases significantly, and the intensities of the bands at 1585 and 1313 cm-1, mainly due to the guanine bases, decrease greatly. In addition, Raman spectra are investigated at different doxorubicin concentrations, and the mean areas ratios of the band at 1450 to that at 1003 cm-1, A1450/A1003, fluctuate according to the doxorubicin concentration increasing, which suggests that doxorubicin affects the relative content of lipid in cells.