Microwave-assisted synthesis of Cu2ZnSnS4 nanocrystals as a novel anode material for lithium ion battery

One-dimensional ordered quantum-ring chains are fabricated on a quantum-dot superlattice template by molecular beam epitaxy. The quantum-dot superlattice template is prepared by stacking multiple quantum-dot layers and quantum-ring chains are formed by partially capping quantum dots. Partially capping InAs quantum dots with a thin layer of GaAs introduces a morphological change from quantum dots to quantum rings. The lateral ordering is introduced by engineering the strain field of a multi-layer InGaAs quantum-dot superlattice.     

Electric field control of nonvolatile four-state magnetization at room temperature

We find the realization of large converse magnetoelectric (ME) effects at room temperature in a magnetoelectric hexaferrite Ba0.52Sr2.48Co2Fe24O41 single crystal, in which rapid change of electric polarization in low magnetic fields (about 5 mT) is coined to a large ME susceptibility of 3200 ps/m. The modulation of magnetization then reaches up to 0.62μ(B)/f.u. in an electric field of 1.14 MV/m. We find further that four ME states induced by different ME poling exhibit unique, nonvolatile magnetization versus electric field curves, which can be approximately described by an effective free energy with a distinct set of ME coefficients.     

Multiple scattering of fractionally charged quasiparticles

We employ shot noise measurements to characterize the effective charge of quasiparticles, at filling factor nu=1/3 of the fractional quantum Hall regime, as they scatter from an array of identical weak backscatterers. Upon scattering, quasiparticles are known to bunch, e.g., only three e/3 charges, or "electrons" are found to traverse a rather opaque potential barrier. We find here that the effective charge scattered by an array of scatterers is determined by the scattering strength of an individual scatterer and not by the combined scattering strength of the array, which can be very small. Moreover, we also rule out intraedge equilibration of e/3 quasiparticles over a length scale of hundreds of microns.     

Discrimination of strain and temperature based on a polarization-maintaining photonic crystal fiber incorporating an erbium-doped fiber

A simple sensing method for simultaneous measurement of temperature and strain is investigated by using a Sagnac fiber loop mirror composed of a polarization-maintaining photonic crystal fiber (PM-PCF) incorporating an erbium-doped fiber (EDF). Amplified spontaneous emission created by a pumped EDF is transmitted to a Sagnac fiber loop mirror. The interference between two counter-propagating signals in a Sagnac fiber loop mirror generates a periodic transmission spectrum with respect to wavelength. When external temperature is increased, the transmission peak power reduces because the amplified spontaneous emission of the EDF is decreased by the applied temperature change (0.04 dB/°C). The peak wavelength is shifted into the shorter wavelength because of the negative temperature dependence of the birefringence of the PM-PCF (0.3 pm/°C). As the applied strain increases, the peak wavelength of the transmission spectrum of the Sagnac loop mirror incorporating the EDF shifts into a longer wavelength (1.3 pm/με) because the phase change of the proposed sensing probe is directly proportional to the applied strain. The transmission peak power, however, is not changed by the applied strain. Since the source and the sensing probe are integrated, the overall system configuration is significantly simplified without requiring any additional broadband light source. Therefore, it is possible to simultaneously measure temperature and strain by monitoring the variation of transmission peak power and peak wavelength, respectively.     

Femtosecond laser ablation of neurons in <Emphasis Type="Italic">C</Emphasis>. <Emphasis Type="Italic">elegans</Emphasis> for behavioral studies

In this paper, the interaction between the inhomogeneous and anisotropic cloak covered infinitely long PEC circular cylinder and the parallel electric-line-source is investigated in detail. First, the permittivity and permeability tensors of the cloak are defined according to Pendry’s model, then the wave equation in the metamaterial cloak is derived; second, the far/near properties of the model are investigated, and using the boundary conditions the electromagnetic fields of the whole region are calculated analytically; finally, based on the analytical expressions, the electric fields of the whole region are demonstrated through numerical results which show the effects of invisibility. Finally, the effects of loss on the performance of the invisible cloak are investigated.     

Multifunctional carbon-coated magnetic sensing graphene oxide-cyclodextrin nanohybrid for potential cancer theranosis

Journal of Nanoparticle Research - Over the last years, an environmentally friendly and economically efficient way of nanoparticle production has been found in the biosynthesis of metal...     

Near infrared to UV dielectric functions of Al doped ZnO films deposited on c-plane sapphire substrate using pulsed laser deposition

Transparent conducting polycrystalline Al-doped ZnO (AZO) films were deposited on sapphire substrates at substrate temperatures ranging from 200 to 300 °C by pulsed laser deposition (PLD). X-ray diffraction measurement shows that the crystalline quality of AZO films was improved with increased substrate temperature. The electrical and optical properties of the AZO films have been systematically studied via various experimental tools. The room-temperature micro-photoluminescence (µ-PL) spectra show a strong ultraviolet (UV) excitonic emission and weak deep-level emission, which indicate low structural defects in the films. A Raman shift of about 11 cm⁻¹ is observed for the first-order longitudinal-optical (LO) phonon peak for AZO films when compared to the LO phonon peak of bulk ZnO. The Raman spectra obtained with UV resonant excitation at room temperature show multi-phonon LO modes up to third order. Optical response due to free electrons of the AZO films was characterized in the photon energy range from 0.6 to 6.5 eV by spectroscopic ellipsometry (SE). The free electron response was expressed by a simple Drude model combined with the Cauchy model are reported.     

The Formation of Pd Nanocrystals from Pd2(dba)3 Microcrystals

As‐grown platelets formed from tris‐(dibenzylideneacetone) dipalladium(0) [Pd₂(dba)₃] precursor in the presence of Pd17 RNA are investigated before and after thermal annealing. Results show that as‐grown platelets are disordered crystals of Pd₂(dba)₃ containing 1?2 nm Pd clusters and platelets grown in the absence of RNA are morphologically and structurally similar to those formed with RNA. The initially formed crystals are so sensitive to environmental variables that the degree of crystallinity can not be determined accurately by electron diffraction. X‐ray crystallography on as‐grown platelets gives a crystal structure consistent with Pd₂(dba)₃, but reveals a composition of ≈Pd_1.07(dba)₃, indicating one Pd atom in Pd₂(dba)₃ is lost from the structure. Both electron beam and thermally induced decomposition of as‐grown Pd₂(dba)₃ platelets having a hexagonal habit on the micrometer scale produces elemental Pd platelets having a hexagonal habit on the nanometer scale. These hexagonal platelets are composed of a partially sparse form of Pd₂(dba)₃ that is initially crystalline but rapidly degrades due to the loss of Pd atoms from organic ligand cages. Once released, Pd atoms aggregate to form Pd clusters, which grow and transform into well‐formed Pd nanocrystals under electron‐beam irradiation or through thermal annealing.