IBMA–metal containing polymers

A new convenient route to metal containing polymers is described. This method involves emulsion co(ter) polymerization of a polar hydrocarbon soluble monomer, N-isobutoxymethylacrylamide (IBMA), with styrene or styrene/butadiene, followed by addition of metals. Metal incorporation is effected by latex or solution techniques. Preparative, atomic adsorption, spectroscopic, film observation, and dilute solution data are presented in support of metal complexation. Structures for the complexes are proposed.     

彩色照片制作技术

彩色照片由于色彩鲜艳．形象逼真，在工农业生产、科研和日常生活中得到广泛应用。本文就校正偏色与曝光谈一下自己的看法。     

用发射光谱分析法检测地膜中金属杂质含量

本文描述农用薄膜中Ａｌ、Ｆｅ、Ｍｇ、Ｃａ、Ｓｉ、Ｃｕ、Ｔｉ杂质元素的发射光谱分析法，该方法直接压样于石墨电极中，简便，快速，取得了满意的结果。     

LP MOVPE growth of AlGalnP/GalnP and its application to visible laser diodes

High-quality and uniform bulk layers of (Al _x Ga_1–x )_0.5In_0.5P (x=0–0.7) and AlGalnP/GainP quantum wells (QWs) are grown on 2°-off (100) GaAs substrates by low-pressure metal organic vapour phase epitaxy at a low growth rate of 0.3 nm s^-1. The amount of lattice mismatch and the variation of PL peak energy of (Al_0.5Ga_0.5)_0.5In_0.5P on the 50-mm substrate are less than 6×10^-4 and 2 meV, respectively. (Al_0.5Ga_0.5)_0.5In_0.5P/Ga_0.5In_0.5P SQWs show narrow PL spectra even from a 0.6 nm well measured at 20 K. The variation of PL peak energy from (Al_0.5Ga_0.5)_0.5In_0.5P/Ga_0.5In_0.5P MQWs is less than 10 meV. Also, as-cleaved AlGalnP/GalnP lasers fabricated by a three-step MOVPE show a pulsed threshold current of 82 mA at room temperature, output power of 12 mW, and the lasing wavelength at 668.2 nm.     

Infrared regularization of the massless scalar free field in two-dimensional space-time via Lorentz expansion

It is shown that Lorentz harmonics provide a natural basis for the expansion and infrared regularization of a massless scalar field in two dimensions. The negative metric operators separate out simply. Each Lorentz component of the field is partially local.     

Diffusion of ethylene glycol accompanied by reactions in poly(ethylene terephthalate) melts

Diffusion coefficients of ethylene glycol (EG) have been measured in poly(ethylene terephthlate) (PET) melts by a quartz-spring sorption apparatus. A simple mathematical model was developed to investigate the sorption behavior accompanied by chemical reactions of EG and PET at high temperatures. Diffusion coefficients are deduced from experimental data for an asymptotically thin sample in order to minimize the effects of reactions. The diffusion coefficient of EG is strongly dependent on the vapor pressure of EG and temperature but not on the molecular weight of PET in this experimental range (degree of polymerization 80–120). The diffusion coefficient of EG in PET melt at 265°C is 2.58 × 10^?7 cm²/s at the limit of zero concentration of EG. The activation energy for diffusion is 38.4 kcal/gmol, and the heat of solution for sorption is ?44.9 kcal/gmol. The concentrations of the volatile materials resulting from reactions in PET-EG system were analyzed with gas chromatography. In addition, a fit of the current model to experimental data yields frequency factors for the polymerization reaction (k₁) and the acetaldehyde formation reaction (k₂) to be 5.84 × 10⁸ cm³/mol ? min and 3.90 × 10¹¹ min^?1, respectively.     

Solutions to the Pólya–Szegö Conjecture and the Weak Eshelby Conjecture

Eshelby showed that if an inclusion is of elliptic or ellipsoidal shape then for any uniform elastic loading the field inside the inclusion is uniform. He then conjectured that the converse is true, that is, that if the field inside an inclusion is uniform for all uniform loadings, then the inclusion is of elliptic or ellipsoidal shape. We call this the weak Eshelby conjecture. In this paper we prove this conjecture in three dimensions. In two dimensions, a stronger conjecture, which we call the strong Eshelby conjecture, has been proved: if the field inside an inclusion is uniform for a single uniform loading, then the inclusion is of elliptic shape. We give an alternative proof of Eshelby’s conjecture in two dimensions using a hodographic transformation. As a consequence of the weak Eshelby’s conjecture, we prove in two and three dimensions a conjecture of Pólya and Szegö on the isoperimetric inequalities for the polarization tensors (PTs). The Pólya–Szegö conjecture asserts that the inclusion whose electrical PT has the minimal trace takes the shape of a disk or a ball.