Materials Literature
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A water-soluble β-cyclodextrin bearing seven naphthoate chromophores forms a very stable 1:1 inclusion complex (shown right) with a merocyanine dye, which mimics the antenna effect in photosynthetic units. The energy transfer from the naphthoate chromophores to the merocyanine is shown to take place with 100 % efficie…
Almost rectangular cavities can be seen in the structure of the title compound (part of the crystal structure shown on the right), the first heteropolyoxo-tungstate with defined micropores. The compound was prepared in a hydrothermal reaction with W, WO3, H3PO4, H2O, and hexamethylenediamine. Potential applications of…
Not just the size but also the multiplication of functions possible through branching is at the forefront of dendrimer chemistry. Owing to the numerous recent key publications by Newkome, Fréchet, Moore, Majoral, Meijer, and others, this Highlight has the dimensions of a minireview.
Abstract Plaques of bisphenol A polycarbonate (PC) were exposed to a water‐saturated atmosphere at temperatures ranging from 40 to 90°C for up to 7 months. Certain samples were exposed under tensile load at 60 and 90°C, 100% RH with stresses ranging from 3.7 to 8.7 MPa. The PC molecular weight was determined by steric…
Mn(ClO4)2 ·6H2O, 2,2'-bipyridine, and NaN3 were used to synthesize [Mn(N3)2-(bpy)]χ, the crystal structure of which (shown below) is characterized by alternating end-on and end-to-end bridging azido ligands. The existence of alternating ferro-and antiferromagnetic interactions between the S = 5/2 ions, as found previo…
The saddle‐shaped porphyrin with the largest deviation from planarity observed to date is found in the crystal structure of [H 4 obrtpp][CF 3 COO] 2 · 0.5 CHCl 3 (H 2 obrtpp = octabromotetraphenylporphyrin). The pyrrole rings in the porphyrin are twisted by 62° with respect to each other, and the β‐pyrrole C atoms are…
Abstract Nanocomposites were produced via sol–gel reactions for tetraethylorthosilicate within the cluster morphology of perfluorosulfonic acid films. Small‐angle x‐ray scattering revealed that the polar/nonpolar nanophase‐separated morphological template persists despite invasion by the silicon oxide phase. Scanning…
Abstract We synthesized nylon 6‐clay hybrid materials using four types of clay minerals, montmorillonite, saponite, hectrite, and synthetic mica. The mechanical properties of their injection molded specimens were measured according to ASTM. Nylon 6‐clay hybrid using montmorillonite was superior to the other hybrids in…
A theoretical and experimental study of the electronic and magnetic structure of Fe 2 P 1-x Si x is performed. A hexagonal-orthorhombic crystal structure transition occurs with increasing Si substitution. The latter crystal structure is extremely complex with six inequivalent Fe sites. The magnetic moments, as obtaine…
We have studied the formation of cuspidal pits during the growth of strained SixGe1−x alloy layers at relatively high supersaturations. The pit formation is directly linked to strain in the alloy layer, and we propose a heterogeneous formation mechanism in which the pits develop from stress-driven surface diffusion as…
Photoluminescence spectra from the Si impurity center in diamond films grown by chemical-vapor deposition techniques were studied at temperatures between 9 and 300 K. Laser excitation at 514.5 nm, and resonant with the zero-phonon absorption line at 737 nm (1.6823 eV), were used. Luminescence lines become narrowed at…
Leakage currents in epitaxial ferroelectric/perovskite-conductor heterostructures reproducibly show diode properties having hysteresis. The hysteresis appears in forward bias, which is positive for electron (n) type conductors and negative for hole (p) type conductors. The hysteresis is due to the increase of conducti…
The energy distribution of ${L}_{3}{M}_{4,5}{M}_{4,5}$ Auger electrons emitted from solid Ag is studied as a function of the exciting photon energy in the ${L}_{3}$ threshold region. The $^{1}G_{4}$ Auger line not only exhibits a Raman-type energy dispersion and a reduced core hole lifetime broadening, but its line sh…
A new, step bunching instability in the growth of stepped surfaces by molecular beam epitaxy MBE is described. It is produced by an elastic mechanism, and is different from the instability discovered by Asaro and Tiller and by Grinfeld. Unlike the Asaro-Tiller-Grinfeld instability (which is expected to occur only unde…
Cr 2 Ge 2 Te 6 is a new layered material belonging to the lamellar ternary M 2 X 2 Te 6 chalcogenides family (where M is a 3 + oxidation state metal and X 2 a silicon or a germanium pair). It was synthesized from a stoichiometric mixture of the elements and heated in a sealed evacuated quartz tube for 20 d at 700 degr…
Recently, electrochromic thin films and thin film devices have attracted more and more interest because of strong possibility to act as smart windows and smart glass that may be widely used in the daily life[1]. The electrochromic thin film devices usually have a five layers structure: an actual electrochromic layer,…
Liquid crystals have long been investigated for non-mechanical beam steering devices. Previous work has approached beam steering by using an electrically addressed cell with multiple electrodes arranged in stripes. By creating a series of steps in the index of refraction profile, the beam experiences an effective wedg…
There is an urgent need to monitor the condition of fluid-filled taped (FFT) cables. The dissolved-gas analysis (DGA) technique that has been successfully applied to power transformers holds great potential for the preventive maintenance of FFT cables. However, before this emerging technique can be properly applied to…
Subcritical crack growth (SCG) and creep deformation at elevated temperatures were investigated in three types of silicon nitrides and glass ceramics under quasi-static and cyclic loading conditions. The SCG behavior was observed at lower temperature in the silicon nitrides which has lower flexural strength at elevate…
ナイロン6およびナイロン6と3種類の熱可塑性ダイマー酸系重合脂肪酸ポリアミド系エラストマーを混合したポリマーアロイの力学特性について検討した. エラストマー添加量の増加による分散粒子径の増大と結晶化度の低下とともに弾性率と降伏強度の低下が生じた. ナイロン6の衝撃強さは18℃から45℃まで昇温しても低い値が示した. これに対し, ナイロン6のポリマーアロイの衝撃強さは温度の上昇につれて著しく向上した. また破壊面と損傷領域のSEMの観察によってナイロン6の破壊プロセスがノッチ先端での塑性拘束による脆性破壊であることを明らかにした. ナイロン6のポリマーアロイの破壊は23℃の場合ナイロン6と同様でノッチ先端の塑性拘束によるものである…