We investigate the formation of quark and diquark condensates in two different situations. First, we study the phenomenon of chiral and color symmetry breaking and their restoration for a uniformly accelerated observer due to the thermalization Hawking-Unruh effect. The gap equations for quark and diquark condensates with finite chemical potential are constructed. The critical value of acceleration is also obtained. Second, we consider the phase transitions in dense matter with quark and diquark condensates in the static Einstein universe at finite temperature and chemical potential. The nonperturbative expression for the thermodynamic potential is obtained. The phase portraits of the system are constructed.
SynopsisPolarization-reversal currents and x-ray profiles under a high dc field were measured on polytrifluoroethylene (PTrFE) samples prepared by melt crystallization at different cooling rates. The results for PTrFE were found to be analogous to those for copolymers of vinylidene fluoride and trifluoroethylene [p(VDF/TrFE)] with low VDF content. Slowcooled and quenched samples showed different x-ray profdes but the same IR spectra. For the slowcooled samples, a polarization reversal was clearly obse~ed as a peak in polarization current, offering evidence for ferroelectric order in F'TrFE. The ferroelectric behavior was found to be unlike that of typical ferroelectric polymers. There are two processes in a polarization reversal, i.e., partial depolarization and polarization reversal, accompanied by crystalline phase transitions.It is noted that no ferroelectric order was observed for the quenched sample which, however, becomes pyroelectric by poling as revealed by our previous studies. We speculate on possible crystal structures of PTrFE based on the published structure models and the present results. The relation between the ferroelectricity and the previously reported pyroelectricity is also discussed.'Present address:
Miscibility was studied for four polyamide blends of 6I/6T [copolymer consisting of 1,6-hexamethylene diamine and isophthalic acid (6I) (70 wt %) and terephthalic acid (6T) (30 wt %)] with MXD6 (polyamide of m-xylenediamine and adipic acid), BAC6 (polyamide of 1,3-bis(aminomethyl)cyclohexane and adipic acid), TR55 (copolymer consisting of nylon 11 (30 wt %), and polyamide of bis(3-methyl, 4-aminocyclohexyl)methane (30 wt %) and isophthalic acid (70 wt %), and CX7323 (polyamide of bis(4-aminocyclohexyl)methane and dodecanedicarboxylic acid), using differential scanning calorimetry, X-ray diffraction method, and electronmicroscopic observation. In quenched MXD6/(6I/ 6T) and BAC6/(6I/6T) blends, MXD6 and BAC6 components were miscible to 6I/6T, but TR55 and CX7323 components were completely phase-separated from 6I/6T. Interestingly on electronmicroscopic observations, TR55 and CX7323 components were seen as droplets in 6I/6T medium when the content is low, but when 50 wt %, a layered structure was constructed with 6I/6T, reminiscent of morphological structure in block copolymer.
The relationship between electric displacement D and electric field E was studied for alicyclic polyamides of 1,3-bis(aminomethyl)cyclohexane and adipic, pimelic and sebacic acids, an aromatic polyamide prepared from hexamethylenediamine (HMD) and isophthalic acid and a copolyamide of HMD with isophthalic and terephthalic acids. Quenched samples of these polyamides were poorly crystalline or amorphous and exhibited a D-E hysteresis loop with the remanent polarization of 26 to 38 mC·m-2. The remanent polarizations disappeared at the glass transition temperature of each sample. The origin of the D-E hysteresis loop is attributable to amide groups in amorphous regions.
We study the level spacing distribution p(s) in the spectrum of random networks. According to our numerical results, the shape of p(s) in the Erdős-Rényi (E-R) random graph is determined by the average degree k and p(s) undergoes a dramatic change when k is varied around the critical point of the percolation transition, k = 1. When k 1, the p(s) is described by the statistics of the Gaussian orthogonal ensemble (GOE), one of the major statistical ensembles in Random Matrix Theory, whereas at k = 1 it follows the Poisson level spacing distribution. Closely above the critical point, p(s) can be described in terms of an intermediate distribution between Poisson and the GOE, the Brodydistribution. Furthermore, below the critical point p(s) can be given with the help of the regularized Gamma-function. Motivated by these results, we analyse the behaviour of p(s) in real networks such as the internet, a word association network and a protein-protein interaction network as well. When the giant component of these networks is destroyed in a node deletion process simulating the networks subjected to intentional attack, their level spacing distribution undergoes a similar transition to that of the E-R graph.
ABSTRACT:Fast quenching from the melt was found to effect greatly the structures and ferroelectric properties of vinylidene fluoride and trifluoroethylene copolymers (P(VDF /TrFE)) in contrast to slow cooling. The results are discussed for high-and low-VDF content divided at about 50 mol% VDF. For the high-VDF copolymers, the quenched samples showed high T, like poled samples, implying an ordered ferroelectric phase. Poling the quenched samples at elevated temperatures produced a ferroelectric polarization the direction of which was restored after cooling from above T,. For the low-VDF copolymers, the quenched samples showed a crystalline phase different from that of the slow-cooled samples, which was found to exist in a metastable state. The quenched samples exhibited no ferroelectricity unlike the slow-cooled samples but poling at elevated temperatures induced pyroelectricity with anomalous temperature dependence. From the present results, the fast quenching seems to produce a phase stable at low temperatures and the poling at elevated temperatures causes crystal growth under an electric field resulting in thermallystable spontaneous polarizations. Crystal structures of the low-VDF copolymers are also speculated based on the present results and published structure models.KEY WORDS Vinylidene Fluoride-Trifluoroethylene Copolymers I Fast Quenching I Melt Crystallization I Ferroelectric Phase Transition I Spontaneous Polarization I Pyroelectricity I Copolymers of vinylidene fluoride and trifluoroethylene (P(VDF/TrFE)) have been extensively studied since the discovery of ferroelectricity in samples with high-VDF content as the first clear example of a ferroelectric polymer.1.2 Ferroelectricity originates in the structural characteristics of the PVDF form I crystal, namely, the all-trans chain conformation for the highest polarization and the pseudohexagonal chain packing to facilitate chain rotation by 60° steps. 3.4 The high-VD F copolymers are of great advantage to the formation of ferroelectricity because the form I crystal is adopted by as-crystallized samples and a high degree of crystallinity is attained by heat treatment. On the other hand, copolymers with VDF content lower than 50 mol% have been found by our study to exhibit intricate ferroelectric behavior, for example, a D-E double hysteresis loop and an abnormally low amount of remanent polarization. 5 Ferroelectricity is a crystal property which is expected to be strongly effected by a method of melt crystallization in semicrystalline polymers, i.e., slow cooling or fast quenching. We have developed a method of fast quenching * Present address:
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