Mechanism of inhibition by copper stearate of the photo-degradation of polyolefins

The effect of a series of transition metal (Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) stearates in retarding the photo-degradation of isotactic polypropylene has been examined and it has been found that the results obtained are quite similar to those for high density polyethylene.Infra-red spectral analysis of the polyethylene and isotactic polypropylene films showed that, in the early stages of the photo-irradiation, photo-chemical reaction of the copper stearate took place in the films to change its structure and that rapid formation of terminal unsaturation occurred only in the films containing copper stearate. The results obtained suggest that the copper stearate provides a radical scavenging function, as well as an ultraviolet light absorbing function, to protect the polymers against photo-degradation.     

High-selectivity,high-flexibility glass hollow-fiber membrane for gas separation

A high gas selectivity, high flexibility glass hollow-fiber membrane based on spinodal phase separation has been prepared by direct winding from glass melt, followed by acid leaching processing.     

Distributions of copper and CuBr in CuBr nanocrystallite-dispersed glasses prepared by copper staining

CuBr nanocrystallite-dispersed glasses were prepared by incorporation of copper into bromide ion-containing borosilicate glass using the technique of copper staining. The copper ion incorporation process was mainly controlled by ionic diffusion from the surface to the interior of the glass. The depth profiles of Cu and CuBr concentration were examined by energy dispersive X-ray analysis and by reference to the change in absorption intensity assigned to the CuBr exciton band along the depth. While the Cu concentration was found to decrease monotonically, the CuBr concentration profile showed a maximum at a distance of 10-50 μm from the glass surface. Although the depth reached by the copper ions became greater with increasing heat-treatment time, the depth at which CuBr was precipitated was found to be saturated. This means that regions were found in the glasses in which no CuBr crystallites precipitated, although migration of Cu ions to these regions had taken place.     

Trudinger type inequalities in and their best exponents

We study Trudinger type inequalities in and their best exponents . We show for , ( is the surface area of the unit sphere in ), there exists a constant such that

for all . Here is defined by

It is also shown that with is false, which is different from the usual Trudinger's inequalities in bounded domains.

     

Deformation Argument under PSP Condition and Applications

In this paper we introduce a new deformation argument, in which C~0-group action and a new type of Palais-Smale condition PSP play important roles. This type of deformation results are studied in [17, 21] and has many different applications [10,11, 17, 21] et al. Typically it can be applied to nonlinear scalar field equations. We give a survey in an abstract functional setting. We also present another application to nonlinear elliptic problems in strip-like domains. Under conditions related to [5,6], we show the existence of infinitely many solutions. This extends the results in [8].     

Highly oscillatory behavior of the activator in the Gierer and Meinhardt system

In this article we construct a new type of solutions for the Gierer and Meinhardt system

Polymorphic packing and dynamics of biodegradable poly(3-hydroxypropionate)

The packing and dynamics of the beta-, gamma-, and delta-forms of poly(3-hydroxypropionate) (P3HP), which represents the basic skeleton of bacterial poly(3-hydroxyalkanoate)s, were investigated by the variable-temperature FTIR and (13)C solid-state NMR measurements (SNMR). Under cooling, most of IR bands in the 1500-750 cm(-1) region were noted to be distinctively blueshifted and enhanced, which should reflect the increased intermolecular interaction and depend on the chain packing of each crystal form. Furthermore, the temperature-dependent splitting of vibration were found to occur at the CH2 bending and rocking for the gamma-form, and at the CH2 bending and C-O-C stretching for the delta-form, while be absent for the beta-form. All the FTIR results indicate that the gamma-form has a stronger intermolecular interaction than the beta-form, although both adopt the all-trans conformation. The IR evidence measured during heating further reveal that the melting of the tightly packed gamma-form would pass through some mesophase, which lacks the regular packing but hold the long-range order along the chains. The delta-form was also found to be tightly packed, and contain at least and most possibly two chains in one unit cell. The CP/MAS (13)C SNMR spectrum of the delta-form was compared with those of the beta- and gamma-forms, and was well explained by combining the gamma-gauche and gamma-eclipsed effects. With considering possible differences in the magnetic dipole-dipole interaction among three crystal forms, the molecular mobilities of crystalline phases were estimated by the values of (13)C spin-lattice relaxation time to rank as delta < gamma < beta. The diversified mobilities of three polymorphic crystalline phases, which is the key to crystalline-structure dependent biodegradability of P3HP, were discussed with considering the packing and conformation.     

Dynamic structure of regioregulated poly(alkylthiophene)s

Solid-state structures of regioregulated poly(3-hexylthiophene) (P3HT) and poly(3-butylthiophene) (P3BT) were investigated using Fourier transform infrared absorption (FT-IR) spectroscopy. This study revealed that a twist glass transition of thiophene twisting for P3HT exists around 300 K ( T gp). Additionally, the influence of annealing on population of glassy crystal, crystal, and plastic crystal phases was explored. The annealed sample is dominated by plastic crystal phase, and this phase increases with annealing temperature below T gp. The frustration against crystallization in P3HT is weaker than that in P3BT. Consequently, the plastic crystal phase is formed as a dominant structure, whereas P3BT forms both a well-defined crystal in the conventional sense and glassy crystal.