Materials Literature
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Zwitterionic chitosan, a chitosan derivative with a unique pH-dependent charge profile, was employed to create a stealth coating on the cationic surface of drug carriers. Zwitterionic chitosans were synthesized by amidation of chitosan with succinic anhydride. The succinic anhydride-conjugated chitosan had an isoelect…
An efficient triple azo coupling reaction between anilines and phloroglucinol furnished a series of C(3)-symmetric molecules 7-9 supporting multiple conjugation pathways that converge at the molecular core. A combination of (1)H/(13)C NMR spectroscopy, X-ray crystallography, and density functional theory computational…
Uniform Y(2)O(3) hollow microspheres have been successfully prepared via a urea-based homogeneous precipitation technique with colloidal melamine formaldehyde (MF) microspheres as templates followed by a subsequent calcination process. X-ray diffraction, energy dispersive X-ray analysis, and Fourier transform infrared…
We report the controllable coiling of colloidal gold nanowires induced by the contraction of their polymer shells. The mechanical energy stored in this process can be released upon removal or swelling of the polymer shells.
Metallic nanowires are useful for fabricating highly integrated nanoscale electrical, magnetic, and photonic devices. However, conventional methods based on bottom-up growth techniques are subject to concerns such as broad distributions in their dimension as well and difficulties in precise placement of the nanowires.…
Bi2Se3 is theoretically predicted1 2and experimentally observed2,3 to be a three dimensional topological insulator. For possible applications, it is important to understand the electronic structure of the planar device. In this work, thickness dependent band structure of molecular beam epitaxy grown ultrathin films of…
Single crystals of FeSe 1- x Te x (0.5≤ x ≤1) have been grown by the Bridgman method. After annealing them at 400 °C for 100 h in vacuum, single crystals of x =0.5–0.9 have exhibited bulk superconductivity. Anisotropic properties of the electrical resistivity and upper critical field, H c2 , have been investigated for…
We derive expressions for the lowest nonlinear elastic constants of amorphous solids in athermal conditions (up to third order), in terms of the interaction potential between the constituent particles. The effect of these constants cannot be disregarded when amorphous solids undergo instabilities such as plastic flow…
Amorphous solids that underwent a strain in one direction such that they responded in a plastic manner "remember" that direction also when relaxed back to a state with zero mean stress. We address the question "what is the order parameter that is responsible for this memory?" and is therefore the reason for the differ…
Femtosecond transient absorption (TA) is used to investigate population dynamics of electronic states in CdTe/CdSe core/shell nanocrystals (NCs) with varying CdSe shell coverage. Upon CdSe shell growth, the CdTe/CdSe NCs show a gradual evolution of surface passivation toward a quasi-type-II charge separation regime. O…
Photostability, inherent fluorescence brightness, and optical modulation of fluorescence are key attributes distinguishing silver nanoclusters as fluorophores. DNA plays a central role both by protecting the clusters in aqueous environments and by directing their formation. Herein, we characterize a new near infrared-…
A method of the mid-IR-laser microscopy has been proposed for the investigation of the large-scale electrically and recombination active defects in semiconductors and non-destructive inspection of semiconductor materials and structures in the industries of microelectronics and photovoltaics. The basis for this develop…
The Si(001) surface subjected to different treatments in ultrahigh vacuum molecular beam epitaxy chamber for SiO$_2$ film decomposition has been in situ investigated by reflected high energy electron diffraction (RHEED) and high resolution scanning tunnelling microscopy (STM). A transition between (2 x 1) and (4 x 4)…
Standing waves near zigzag and armchair edges, and their Berry's phases, are investigated. It is suggested that the Berry's phase for the standing wave near the zigzag edge is trivial, while that near the armchair edge is nontrivial. A nontrivial Berry's phase implies the presence of a singularity in parameter space.…
A detailed investigation of the electronic - and magneto - transport properties of Nd0.8Sr0.2MnO3 with the variation of grain size (down to 42 nm) is presented here. Interestingly, we observe that the ferromagnetic insulating state is suppressed and a metallic state is stabilized as the grain size of the sample is red…
The magnetic properties of isolated TbPc(2) molecules supported on a Cu(100) surface are investigated by X-ray magnetic circular dichroism at 8 K in magnetic fields up to 5 T. The crystal field and magnetic properties of single molecules are found to be robust upon adsorption on a metal substrate. The Tb magnetic mome…
Optical second-harmonic generation from gold nanoparticles is investigated both experimentally and theoretically. The contribution of octupoles is reported for the first time in the second-harmonic emission pattern, by using an harmonic polarization in the scattering plane. The experimental results presented here for…
Unbiased search on the potential energy surface of medium-sized boron clusters, with B(80), B(74), and B(68) as representatives, was carried out using simulated annealing incorporated with first-principles molecular dynamics. These boron clusters thermodynamically prefer the B(12)-centered core-shell structures, which…
The plasmon resonances in metallic nanorods are investigated using fully quantum mechanical time-dependent density functional theory. The computed optical absorption curves display well-defined longitudinal and transverse plasmon resonances whose energies depend on the aspect ratio of the rods, in excellent agreement…
Silica-titania hollow nanoparticles (HNPs) with uniform diameters of 25, 50, 75, 100, and 125 nm were fabricated by dissolution and redeposition method in order to evaluate size dependent cellular response. Surface-modified HNPs with cationic, anionic, and neutral functional group were prepared by silane treatment. We…