Ferro electrics

Kato T, Kihara H, Uryu T, Ujiie S, Iimura K, Frechet JMJ, Kumar U (1994) Ferro-electrics 148 1303... 

Consideration of the structure of polyvinylidene fluoride (65) assuming a barrier of 3 kilo cal per mole for rotational minima of conformation of the chain by A. E. Tonelli (66) led to detailed conformation and its implications for dipole structure (Fig. 22). Indeed, the material can approximate a ferro electric. It is thus of interest in our expectations of the environments that polymers can provide for the creation of new phenomena. The total array of dipoles in polyvinylidene fluoride will switch in about 3 microseconds at 20°C with 200 megavolts per meter field. The system becomes much slower at lower temperatures and fields. But we do have a case of macroscopic polarization intrinsic to the polymer molecules, which thus supplements the extensive trapping and other charge of distribution phenomena that we have discussed in connection with electrets. 

Optically active EP is an important C3 chiral building block for the synthesis of chiral pharmaceuticals such as j9-adrenergic blockers [11 -13], vitamins [14,15], pheromones [16], natural products [17], and new materials such as ferro-electric crystals [18]. Racemic EP can be made via 2,3-DCP and l,3-dichloro-2-pro-panol (1,3-DCP) synthesized from propylene by organic synthesis [19] however, a practical production method for optically active EP has not yet been established. Racemic 2,3-DCP, which is easily synthesized by the chemical... 

A determined search for superconductivity in metallic oxides was initiated in mid-summer of 1983 at the IBM, Zurich Research Laboratories in Riischliken, Switzerland. This research effort was an extension of previous work (145) on oxides, namely, Sr1.xCaxTiOs, which exhibited some unusual structural and ferro-electric transitions (see Section 2.2a). During the summer of 1983, the superconductivity research was focussed on copper-oxide compounds. Muller had projected the need for mixed Cu2+/Cu3+ valence states, Jahn-Teller interactions (associated with Cu2+ ions), and the presence of room temperature metallic conductivity to generate good superconductor candidates. These researchers then became aware of the publication by Michel, Er-Rakho, and Raveau (146) entitled ... 

Thomas, N. W. (1989). A bond-valence approach to one-dimensional ferro-electrics. Ferroelectrics 100, 77-100. 

The success of an ultrasonic NDC application depends upon the selection of the best-qualified transducer (i.e., one with optimum frequency response, pulse width and shape). Transducer characteristics can be customized through the use of the best-suited piezoelectric material, such as lead zirconate-lead titanate, lead metaniobates, polymer piezoelectrics, and other advanced ferro-electric materials. 

The EO effect is a second-order nonlinear optical (NLO) effect. Only non-centrosymmetrical materials exhibit second-order NLO effects. This non-centrosymmetry is a condition, both at the macroscopic level of the bulk arrangement of the material and at the microscopic level of the individual molecule. All electro-optic modulators that are presently used by telecom operators are ferro-electric inorganic crystals. The optical nonlinearity in these materials is to a large fraction caused by the nuclear displacement in the applied electric field, and to a smaller fraction by the movement of the electrons. This limits the bandwidth of the modulator. The nonlinear response of organic materials is purely electronic and, therefore, inherently faster. 

Class II/III dielectrics consist of high-permittivity ceramics based on ferro-electrics. They have er values between 2000 and 20 000 and properties that vary more with temperature, field strength and frequency than Class I dielectrics. Their dissipation factors are generally below 0.03 but may exceed this level in some temperature ranges and in many cases become much higher when high a.c. fields are applied. Their main value lies in their high volumetric efficiency (see Table 5.1). 

O Neill, T.J., Tebbutt, J.S., Challis, R.E. 2001. Convergence criteria for scattering models of ultrasonic wave propagation in suspensions of particles. IEEE Trans. Ultrasonics, Ferro-electrics and Frequency Control 48, 419-424. 

Dextran is used in gel precipitation for purifying, separating,347,348 and concentrating metals for use as nuclear-reactor fuels,349,350 catalysts,350-352 ceramic coatings,349 refractories, ferro-electric materials,351,352 and pigments.353... 

In 1958 Cahn and Hilliard proposed a phenomenological theory for surface and interfacial tensions that was based on a general formalism for heterogeneous systems. It has a certain analogy with the descriptions of non-uniformities in magnetic and ferro-electric domains in solids. The basic idea was that the loeal Helmholtz energy density per molecule / is expanded in a Taylor series about, the corresponding quantity in a uniform phase. Mathematically,... 

R274 A. Bussmann-Holder and N. Dalai, Polarizability Induced Cooperative Proton Ordering, Coexistence of Order/Disorder and Displacive I>y-namics and Isotope Effect in Hydrogen-Bonded Ferroelectrics , Ferro-electrics, 2000, 237, 305... 

Katrusiak, A. (1993). Geometric effects of H-atom disordering in hydrogen-bonded ferro-electrics. Phys. Rev. B 48, 2992-3002. 

S)-2,3-chloro- 1-propanol (/ )-2,3-dlchloro-1 -propanol 100% ee Cl yf OH H Cl (5)-2.3-dichloro-1-propanol 100% ee base New materials, such as chiral polymers, ferro-electric liquid crystals, etc. 

G. SHIRANE, S.M. SHAPIRO, R. COMES, A.F. GARITO and A.J. HEEGER -Phys. Rev. (1976). A preliminary report of these results was reviewed by G. SHIRANE at the Conference on Low Lying Vibrational Modes and their relationship to Superconductivity and Ferroelec-tricity, SAN JUAN, December 1-4, 1975 - to be published in Ferro-electrics. 

Ordering of orthophosphate anions results in ferro-electricity in K2Bi30(P04)2 whereas in AM2(P04)3 types (A = Li-Cs, Ag, Cu M = Ce, Th, U) it results from the alignment of A cation displacements from the center of AOg polyhedra. A M P04 materials (e.g. A = Rb, Cs M = Mg, Co, Zn) containing tetrahedral MP04 frameworks can undergo ferroelectric transitions due to the coupled rotations of the tetrahedra. 

Takahashi Y, Tadokoro H (1984) Structure and disorder of poly(vinylidene fluoride). Ferro-electrics 57 187... 

J. F., Recent results on switching, fatigue and electrical characterization of sol-gel based PZT capacitors, in Proc. Second Symp. on Integrated Ferro-electrics, 1990, pp. 79-93. 

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