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Abstract: The temperature dependence of the heat capacity of the 0.7PbNi1/3Nb2/3O3-0.3PbTiO3 compound has been studied in the temperature range 120–800 K. The temperature dependence of the heat capacity C p has two diffuse anomalies in the temperature ranges 250–450 K and 450–650 K and a λ anomaly at temperatures T ≈ 225 K. The results are discussed with inclusion of the dielectric and structural data.

The study of PSN-PT ferroelectric relaxor ceramics exhibiting extreme values of some physical parameters near the morphotropic phase boundary is reported. The results are discussed to account for the relaxor properties related to defects and disordering of the PSN-PT system.

Dielectric properties of 0.4PbZn1/3Nb2/3O3-0.3PbSc1/2Nb1/2O3-0.3PbMg1/3Nb2/3O3- (0.4PZN- 0.3PSN-0.3PMN) ceramics are presented for 200 < T < 500 K and 20 Hz < ν < 1 MHz. Dielectric constant is very high (more 14000) in the vicinity of the peak. Anomalous broad dielectric relaxation have been observed near the temperature of the maximum permittivity, Tm (at 1 kHz). External bias field considerably lowers the value of dielectric losses at low frequencies due to decrease of polar nano regions contribution to the dielectric permittivity.

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The basic features of dielectric nonlinearity in the nonpolar phase of heterovalent perovskite niobates containing lead - PbB'B"O 3 (B' - Mg 2+ , Zn 2+ ; B" - Nb 5+ ) are reported. Behaviour of dielectric permeability is studied as a function of electric field and temperature. Compositions most favourable for tuneable capacitors are identified.

Reversible dielectric permeability l ' r (E = ) of 0.5PbNi 1/3 Nb 2/3 O 3 - 0.5Pb(Zr,Ti)O 3 ferroelectric ceramics is studied at different lead titanate to zirconate ratios. Particular features of dielectric response - fractures and small plateaux on the l ' r (E = ) curve are observed at some values of the bias field E = . The anomalies are explained by phase transformations induced by applied field and suggest of broadening of the morphotropic phase boundary in the system.

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The history effects on dielectric response in (Pb1-xBax)(Sc0.5Nb0.5)O3 ferroelectric ceramics are studied. A bias field applied to PSN at temperatures T>Tm induce transition from the superparaelectric to a ferroelectric-like phase. Transition from relaxor phase to ferroelectric phase occurs in PSN spontaneously at temperatures T

Properties of ferroelectric and superconductor materials depending on microstructure formation at thermal processing are studied. Ferroelectric ceramic samples prepared by conventional technology and MTG processed high temperature superconductor bulk samples are examined. Results of electron microscopy studies of surface morphology and structure of fractures are reported.

Obtaining of novel thin film materials for electrically tuneable capacities is one of the current problems of ferroelectric material application. The most appropriate materials are the ferroelectric lead-containing niobates: PbMg1/3Nb2/3O3 (PMN), PhZn1/3Nb2/3Os (PZN), PbNi1/3Nb2/3O3 (PNN) and their solid solutions were synthesized by solid state reactions at 800-900 °C from oxides. Results of the studies of thermal dependence of dielectric permeability and loss factors of the synthesized solutions are provided together with reciprocal dielectric permeability as function of temperature and electric field intensity. The dielectric characteristics of nonlinear materials are reported experimentally observed.

Bias field effect on the dielectric permittivity is studied in Badoped lead scandium niobate ferroelectric ceramics (PBSN-x) prepared by conventional technology. Results of this work allow to analyse the mechanism of possible formation and motion of domain and/or phase boundaries in the explored ferroelectric ceramics.

The effect of barium concentration on polarization and depolarization currents I(T) in ferroelectric ceramics Pb1-xBaxSc0.5Nb0.5O3 (PBSN-x; x=0; 0.04) is reported. The dielectric response of samples with different history to low and infralow frequencies is compared.

Obtaining of novel thin film materials for electrically tuneable capacities is one of the current problems of ferroelectric material application. Suitable ferroelectric compounds exhibiting broad phase transitions and small dielectric loss in the paraelectric phase have been searched for the purpose. Lead-containing niobates PbMg1/3Nb2/3O3 (PMN), PbNi1/3Nb2/3O3 (PNN) and PbZn1/3Nb2/3O3 (PZN) and their solid solutions have been found as most appropriate. Materials have been synthesized by solid phase reactions from the relevant oxides; ceramic samples were obtained by conventional ceramic technology. Results of the studies of thermal dependence of dielectric permeability and loss factors of the synthesized ternary solutions are provided together with reciprocal dielectric permeability as function of temperature and electric field intensity.

PURPOSE: The Gunther Tulip filter is a permanent filter that has a hook to permit retrieval. The authors report their preliminary clinical evaluation of the filter with regard to feasibility and safety of retrieval. MATERIALS AND METHODS: Nine men and six women who ranged in age from 17 to 79 years (mean, 51 years) underwent treatment with use of the Gunther Tulip filter. Patients judged to require caval interruption for <14 days were selected to receive the filter and retrieval was planned for all patients. Indications for filter placement were: recent pulmonary embolism (PE) or proximal deep vein thrombosis (DVT) with a contraindication to anticoagulation (11 patients), massive PE treated with thrombolytic therapy (one patient), PE with heparin-induced thrombocytopenia (one patient), and prophylaxis after major trauma (two patients). Patients were followed for inferior vena cava (IVC) thrombosis, bleeding, and recurrent DVT or PE. RESULTS: In all nine patients in whom it was attempted, the filter was successfully snared and retrieved via a jugular approach. The mean implantation period was 8.6 days (range, 5-13 days). Retrieval required 2.2-13 minutes (mean 5.3 minutes) of fluoroscopy. No caval injuries occurred as a result of retrieval. All retrieved filters had strands of organized thrombus on the filter struts. The patients were followed for 52-285 days (mean, 115 days) after retrieval. One patient developed a recurrent DVT 230 days after retrieval. No other patients developed a recurrent DVT and no patients developed IVC thrombosis, bleeding, or PE. Six filters were not retrieved: five because of an ongoing contraindication to anticoagulation and one because the patient died of causes unrelated to the filter. CONCLUSION: This preliminary study confirms the feasibility and safety of retrieval of the Gunther Tulip filter up to 13 days after implantation.

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