Synergistically toughening high‐density polyethylene with calcium carbonate and elastomer

The microstructure, impact strength, and rheological properties of blends consisting of high‐density polyethylene (HDPE) and maleated poly (ethylene‐octene) (POEg) and/or calcium carbonate (CaCO₃) were investigated. The improvement of impact strength of HDPE/POEg was limited due to the high miscibility between them. The introduction of CaCO₃ had a negative impact on the toughness of the matrix because of the poor interfacial adhesion. In ternary blends of HDPE/POEg/CaCO₃, an elastomer layer was formed around CaCO₃ particles due to the strong interaction between POEg and CaCO₃, which improves the HDPE‐CaCO₃ interfacial strength and the toughness of the blends. A significant enhancement of dynamic viscosity, storage modulus, and the low‐shear viscosity were observed as the results of the high miscibility of HDPE with POEg and strong interaction between POEg and CaCO₃. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3213–3221, 2005     

Crystallization behavior and thermal stability of poly(trimethylene terephthalate)/clay nanocomposites

Poly(trimethylene terephthalate) (PTT)/montmorillonite (MMT) nanocomposites were prepared by the solution intercalation method. Two different kinds of clay were organomodified with an intercalation agent of cetyltrimetylammonium chloride (CMC). X‐ray diffraction (XRD) indicated that the layers of MMT were intercalated by CMC, and interlayer spacing was a function of the cationic exchange capacity of clay. The XRD studies demonstrated that the interlayer spacing of organoclay in the nanocomposites depends on the amount of organoclay. From the results of differential scanning calorimetric analysis, it was found that clay behaves as a nucleating agent and enhances the crystallization rate of PTT. The maximum enhancement of the crystallization rate for the nanocomposites was observed in nanocomposites containing about 1 wt % organoclay with a range of 1–15 wt %. From thermogravimetric analysis, we found that the thermal stability of the nanocomposites was enhanced by the addition of 1–10 wt % organoclay. According to transmission electron microscopy, the organoclay particle was highly dispersed in the PTT matrix without a large agglomeration of particles for a low organoclay content (5 wt %). However, an agglomerated structure did form in the PTT matrix at a 15 wt % organoclay content. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2902–2910, 2003     

Monolithic two-dimensional surface emitting arrays of GaAs/AlGaAs lasers

Surface emitting lasers are of interest for various applications such as monolithic two-dimensional arrays and optical interconnects for integrated optics. Moreover, surface emitting lasers offer the advantage of wafer processing and testing. Several approaches for achieving surface emission are described. In addition, TRW s fabrication of a large monolithic two dimensional array of GaAs/AlGaAs surface emitting lasers which contains a total of 100 lasers is reported.     

Near- and mid-infrared spectroscopy of sol–gel derived ormosils: vinyl and phenyl silicates

The suitability of ormosils as photonic materials was investigated. Vinyl and phenyl silicates were synthesised below 100°C. A detailed assignment of mid-infrared vibrational absorption bands is given. This allowed assignment of overtone and combination bands in the near-infrared region and an assessment of residual water contamination, which is low and can be expelled by evacuation. These ormosils have low intrinsic and extrinsic optical absorption in the visible spectral region and at useful wavelengths in the near-infrared.     

Conversion of furans into gamma-hydroxybutenolides: use of sodium chlorite

3,4-disubstituted furans are converted into gamma-hydroxy-butenolides by treatment with NaClO(2) in aqueous EtOH containing NaH(2)PO(4).     

Spanning Trails Connecting Given Edges

Suppose that is the set of connected graphs such that a graph G if and only if G satisfies both (F1) if X is an edge cut of G with |X|3, then there exists a vertex v of degree |X| such that X consists of all the edges incident with v in G, and (F2) for every v of degree 3, v lies in a k-cycle of G, where 2k3.In this paper, we show that if G and (G)3, then for every pair of edges e,fE(G), G has a trail with initial edge e and final edge f which contains all vertices of G. This result extends several former results.     

High quality InAlN/GaN heterostructures grown on sapphire by pulsed metal organic chemical vapor deposition

High quality InAlN/GaN heterostructures are successfully grown on the (0 0 0 1) sapphire substrate by pulsed metal organic chemical vapor deposition. The InAlN barrier layer with an indium composition of 17% is observed to be nearly lattice matched to GaN layer, and a smooth surface morphology can be obtained with root mean square roughness of 0.3 nm and without indium droplets and phase separation. The 50 mm InAlN/GaN heterostructure wafer exhibits a mobility of 1402 cm²/V s with a sheet carrier density of 2.01×10¹³  cm^?2, and a low average sheet resistance of 234 Ω/cm² with a sheet resistance nonuniformity of 1.22%. Compared with the conventional continual growth method, PMOCVD reduces the growth temperature of the InAlN layer and the Al related prereaction in the gas phase, and consequently enhances the surface migration, and improves the crystallization quality. Furthermore, indium concentration of InAlN layer can be controlled by adjusting the pulse time ratio of TMIn to TMAl in a unit cycle, the growth temperature and pressure, as well as the InAlN layer thickness by the number of unit cycle repeats.     

A Classification of Horizontally Homothetic Submersions from Space Forms of Nonnegative Curvature

In this paper, it is proved that for n 2, any horizontallyhomothetic submersion : Rⁿ⁺¹ (Nⁿ, h) is a Riemannian submersionup to a homothety. It is also shown that if : Sⁿ⁺¹ (Nⁿ, h)is a horizontally homothetic submersion, then n = 2m, (Nⁿ, h)is isometric to CP^m and, up to a homothety, is a standard Hopffibration S^2m+1 CP^m. 2000 Mathematics Subject Classification53C20, 53C12.     

Multifold enhancement of quantum dot luminescence in plasmonic metamaterials

We report that hybridizing semiconductor quantum dots with plasmonic metamaterial leads to a multifold intensity increase and narrowing of their photoluminescence spectrum. The luminescence enhancement is a clear manifestation of the cavity quantum electrodynamics Purcell effect and can be controlled by the metamaterial's design. This observation is an essential step towards understanding loss compensation in plasmonic metamaterials with gain media and for developing metamaterial-enhanced gain media.     

Synthesis and characterization of the n-butyl palmitate as an organic phase change material

In this research, the n-butyl palmitate was synthesized using the esterification reaction of the PA with n-butanol. The ¹H nuclear magnetic resonance and Fourier transform infrared illustrated that the hydroxyl group and carboxyl group disappeared, and the ester bond appeared after the reaction, explaining that n-butyl palmitate was successfully fabricated. The differential scanning calorimetry indicated that the phase-transition temperature and latent heat are 12.6 °C and 127.1 J g^?1, which was suited to use in low-temperature fields such as food, pharmaceutical, and biomedical. The thermogravimetric analysis suggested that it had great thermal stability during the phase change process. In addition, the thermal conductivity of the n-butyl palmitate was slightly higher than other fatty acid ester, and the 500 thermal cycles test results indicated that it had excellent thermal reliability. Therefore, the n-butyl palmitate is deduced to share great thermal energy storage ability in terms of latent heat thermal energy system applications.