Materials Literature
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Staying in shape: The second and third generations of a new dendron system switch from left-handed to right-handed helical conformations upon a change in solvent from THF to water (picture; left). This inversion occurs in tandem with conformational shifts about the OCCO bonds of a subset of terminating glycol chain…
Two new polynuclear complexes [Ni6(amox)6(mu6-O)(mu3-OH)2](Cl2).6H2O and [Cu3(amox)3(mu3-OH)(mu3-Cl)](ClO4).4H2O (amox- = anion of 4-amino-4-methyl-2-pentanone oxime) have been synthesized and characterized structurally and magnetically. The Ni(II) complex contains a novel Chinese-lantern-like Ni6 cage centered by an…
The structure and magnetic entropy change of melt-spun LaFe11.57Si1.43 ribbons have been investigated. Here, the 1:13 phase with cubic NaZn13-type structure is obtained by a short-time annealing (1000°C∕1h) in melt-spun-type materials, which in contrast, requires a much longer time annealing at high temperature to dev…
We measured the near-infrared photoluminescence decay time in several different-chirality single-walled carbon nanotubes by time-resolved picosecond luminescence spectroscopy. Together with the results of resonant pump-and-probe spectroscopy this leads to a carrier lifetime in the first excited state of semiconducting…
Thiol-capped water-soluble PbS nanocrystals (NCs) stabilized with 1-thioglycerol, dithioglycerol, or a mixture of 1-thioglycerol/dithioglycerol (TGL/DTG) were prepared via one-stage synthesis at room temperature. We found that NCs stabilized with a TGL/DTG mixture show efficient and stable infrared photoluminescence c…
Stereoblock poly(lactic acid) consisting of D- and L-lactate stereosequences can be successfully synthesized by solid-state polycondensation of a 1:1 mixture of poly(L-lactic acid) and poly(D-lactic acid). In the first step, melt-polycondensation of L- and D-lactic acids is conducted to synthesize poly(L-lactic acid)…
A general expression of the current–voltage characteristics of a ballistic nanowire field-effect transistor (FET) is derived. At T=0, the conductance, which is equal to the quantum conductance multiplied by the number of channels at zero bias, decreases stepwise toward current saturation as the drain bias is increased…
We study the optical properties of excitons in one-dimensional (1D) nanostructures at low temperatures. In single $\mathrm{C}\mathrm{d}\mathrm{S}\mathrm{e}/\mathrm{Z}\mathrm{n}\mathrm{S}$ core-shell nanorods we observe a fine structure splitting and explain it by exchange interaction. Two peaks are observed with diffe…
A high temperature Seebeck coefficient and electrical resistivity measurement apparatus has been designed and built for measuring advanced thermoelectric materials. The apparatus covers the range of temperatures from 300to1300K. Different sources of errors involved in the two measurements are discussed. The accuracy o…
We demonstrate optical trapping and manipulation of transparent microparticles suspended in a thermotropic nematic liquid crystal with low birefringence. We employ the particle manipulation to measure line tension of a topologically stable disclination line and to determine colloidal interaction of particles with perp…
( Ba 0.90 Ca 0.10 ) ( Zr 0.25 Ti 0.75 ) O 3 (BCZT) relaxor ferroelectric ceramics with grain sizes of 0.85, 2.5, 15, and 30μm were prepared from powders synthesized using a sol-gel process. The effects of grain size and dc field on the dielectric properties and tunabilities of BCZT ceramics were investigated. As the g…
Compressed S and Se are studied by x-ray diffraction with synchrotron radiation up to 160 GPa. The S-IV phase is shown to have a body-centered monoclinic structure and to be stable between 83 and 150 GPa on pressure increase, where it transform to S-V with a primitive rhombohedral $β$-Po structure. Observation of the…
The effect of surface roughness on the structure of liquid crystalline fluids near solid substrates is studied by Monte Carlo simulations. The liquid crystal is modelled as a fluid of soft ellipsoidal molecules and the substrate is modelled as a hard wall that excludes the centres of mass of the fluid molecules. Surfa…
We have calculated band-edge energies for most combinations of zincblende AlN, GaN, InN, GaP, GaAs, InP, InAs, GaSb and InSb in which one material is strained to the other. Calculations were done for three different geometries, quantum wells, wires, and dots, and mean effective masses were computed in order to estimat…
We review recent molecular dynamics simulations of thermally activated undulations and defects in the lamellar $L_α$ phase of a binary amphiphile-solvent mixture, using an idealized molecular coarse-grained model: Solvent particles are represented by beads, and amphiphiles by bead-and-spring tetramers. We find that ou…
We investigate pores in fluid membranes by molecular dynamics simulations of an amphiphile-solvent mixture, using a molecular coarse-grained model. The amphiphilic membranes self-assemble into a lamellar stack of amphiphilic bilayers separated by solvent layers. We focus on the particular case of tension less membrane…
The structures and symmetries of single-walled carbon nanotubes (SWNTs) are introduced in detail. The physical properties of SWNTs induced by their symmetries can be described by tensors in mathematical point of view. It is found that there are 2, 4, and 5 different parameters in the second, third, and fourth rank ten…
This study prepared (1−x)BaTiO3–xCaTiO3 (x=0.20–1.0) ceramics. Their structural and electric properties were analyzed. High electrostrictive strain of 0.22%, higher by 157% as compared to BaTiO3 ceramic, was obtained near the solubility limit in the side of composite (x=0.23), which is a diphasic ceramic composed of a…
ADVERTISEMENT RETURN TO ISSUEPREVNotePhysicochemical Characterizations of Self-Assembled Nanoparticles of Glycol Chitosan−Deoxycholic Acid ConjugatesKwangmeyung Kim, Seunglee Kwon, Jae Hyung Park, Hesson Chung, Seo Young Jeong, Ick Chan Kwon, and In-San KimView Author Information Biomedical Research Center, Korea Inst…
We review various methods to investigate the statics and the dynamics of collective composition fluctuations in dense polymer mixtures within fluctuating-field approaches. The central idea of fluctuating-field theories is to rewrite the partition function of the interacting multi-chain systems in terms of integrals ov…