Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Applied electric fields are known to induce significant changes in the properties of systems of polarizable molecules or particles. For rod-shaped molecules, the field-induced behavior can be rather surprising, as in the case of the negative electric birefringence of concentrated solutions of rodlike polyelectrolytes.…
Strong optically stimulated luminescence (OSL), stimulated by blue light, has been observed, for the first time, in natural calcium fluoride (CaF(2)) phosphor, used as thermoluminescence dosemeters. Traps responsible for all three thermoluminescence (TL) peaks appearing upto 300 degrees C, i.e. 126, 196 and 264 degree…
Abstract Hybrid nanocomposite films of poly(vinylsilsesquioxane) (PVSSQ) and polyimide (PI) (PI/PVSSQ) were prepared via sol‐gel process from triethoxyvinylsilane (VSSQ) and thermal imidization from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA)‐ p ‐phenylene diamine (PDA) polyamic acid (BPDA‐PDA PAA). We invest…
Modelling and analysis of the high-voltage flyback transformer utilised in small-sized high-voltage power supplies are presented. The equivalent circuit model, frequency characteristics and transient behaviour are investigated to analyse the effects of parasitic parameters in the discontinuous conduction mode. Simulat…
We have synthesized a coil-rod-coil molecule based on a reactive rod block that self-organizes into a 3-D hexagonal close-packed (hcp) bundle structure in the melt state. Photo-cross-linking within an aromatic bundle yielded macromolecular disklike objects (molecular weight of 330 kDa) with a narrow size distribution…
We present a review of our initial studies concerning the control of polymorphism in semicrystalline polymers with cyclodextrins (CDs). CDs are cyclic starch oligomers with six (α-CD), seven (β-CD), and eight (γ-CD) α-1,4-linked glucose units possessing bracelet structures with hydrophobic and hydrophilic interiors an…
We report a reversible liquid-solid transition upon heating of a simple solution composed of a-cyclodextrine (alpha CD), water, and 4-methylpyridine. These solutions are homogeneous and transparent at ambient temperature and solidify when heated to temperatures between 45 degrees and 75 degrees. Quasielastic and elast…
As trivalent ${\mathrm{Nd}}^{3+}$ and divalent ${\mathrm{Ca}}^{2+}$ ions have virtually the same ionic size, ${\mathrm{Nd}}_{x}{\mathrm{Ca}}_{2\ensuremath{-}x}{\mathrm{FeMoO}}_{6}$ is a quasi-ideal material to explore electron-doping effects in double perovskites. We report here a study of its structural, magnetic, an…
Porous thin films have been fabricated by physical vapor deposition at an extremely oblique angle of incidence (85°). This deposition technique, called glancing angle deposition (GLAD), was used to create thin films composed of isolated helical columns. By investigating a variety of dielectrics, we found that helical…
Can magnetic interactions between single-molecule magnets (SMMs) in a crystal establish long-range magnetic order at low temperatures deep in the quantum regime, where the only electron spin fluctuations are due to incoherent magnetic quantum tunneling (MQT)? Put inversely: can MQT provide the temperature dependent fl…
Recently, a novel, neural-networks-based method, the DFT-NEURON method, was developed to improve the accuracy of first-principles calculations and was applied to correct the systematic deviations of the calculated heats of formation for small-to-medium-sized organic molecules (Hu, L. H.; Wang, X. J.; Wong, L. H.; Chen…
Far infrared spectra of 14 commonly used explosive samples have been measured by using Fourier Transform Infrared Spectroscopy (FTIR) and THz Time-Domain Spectroscopy (THz TDS). New absorption resonances between 20 cm<sup>-1</sup> and 650 cm<sup>-1</sup> are reported. Below 20 cm<sup>-1</sup>, no clear absorption reso…
The preparation and properties of [Mn(4)O(3)(O(2)CPh-R)(4)(dbm)(3)] (R = H, p-Me, p-OMe, and o-Cl; dbm(-) is the anion of dibenzoylmethane) single-molecule magnets (SMMs) with virtual C(S) symmetry are reported. They were prepared by controlled potential electrolysis in 26-80% yields. The structures comprise a distort…
We studied the mechanism of CO oxidation on O-covered Pt(111) surfaces during CO exposure by means of time-resolved near edge x-ray absorption fine structure spectroscopy. Two distinct reaction processes were found to occur sequentially; isolated O atoms and island-periphery O atoms contribute to each process. Combina…
Here, we present a strategy whereby a water-soluble tricycloquinazoline ( TCQ ) core is generated by hydrolysis of the corresponding nonionic hexaacetate, presenting itself as a potential (discotic) mesogen. The in situ generated core fragment was then used as a hexaanionic building block (or tecton) for assembly into…
The influence of gravity on a suspension of sterically stabilized colloidal gibbsite platelets is studied. An initially isotropic-nematic biphasic sample of such a suspension develops a columnar phase on the bottom on prolonged standing. This phenomenon is described using a simple osmotic compression model. We perform…
Thin polyimide layers have been patterned via a μ-rubbing process that can induce the homogeneous planar alignment or erase the previous alignment history of liquid crystals (LCs) that it comes into contact with. The Figure shows optical micrographs of two patterned polyimide substrates with LCs sandwiched between the…
The thermal conductivity of a Y-junction carbon nanotube with a (14,0) trunk splitting into two (7,0) branches has been investigated using a molecular dynamics approach. It has been found that the thermal conductivity of the Y-junction nanotube is less than that of a corresponding straight (14,0) nanotube, due to latt…
The ruthenium(II) porphyrin fluorophore complexes [Ru(TPP)(CO)(Ds-R)] (TPP = tetraphenylporphinato dianion; Ds = dansyl; R = imidazole (im), 1, or thiomorpholine (tm), 2) were synthesized and investigated for their ability to detect nitric oxide (NO) based on fluorescence. The X-ray crystal structures of 1 and 2 were…
The copper metalation into the hexaphyrins is accompanied by large structural changes to give four complexes exhibiting gable structures and varying antiferromagnetic couplings.