The influence of Pb vacancies on the properties of PZT-type ceramics transducers

This article is dedicated to prof. J. Ranachowski The result of investigations of the influence of lead vacancies on the crystalline structure of PZT-type ceramic piezoelectric materials is presented. The solid solution of PbTiO3 - PbZrO3 - sigma n=13 Pb(B'1-alpha B''alpha)O3, characterized by the perovskite-type structure (ABO3), is the basis of those materials. The lead vacancies (VPb) was originated by a thermal treatment. Investigations of the influence of the lead deficiency on the crystalline structure of PZT-type ceramics have been performed for solid solutions characterized by compositions corresponding to the tetragonal or rhombohedral boundary of the morphotropic region (PCR-1, PCR-8: Piezoelectric Ceramics of Rostov) and to tetragonal phase region compositions (ceramics of Pb1-x(Zr0.39Ti0.59W0.01Cd0.01) O3). It has been found that the deficiency in lead causes a reconstruction of the perovskite phase crystalline structure or a change of the elementary cell parameters of that phase. The solid solutions on the basis of Pb(Zr,Ti)O3 resolve themselves into PbTiO3, ZrO2 and PbO when the lead deficiency caused by thermal treatment increases

Pressure effect on the in-plane magnetic penetration depth in YBa_2Cu_4O_8

We report a study of the pressure effect (PE) on the in-plane magnetic field penetration depth lambda_{ab} in YBa_2Cu_4O_8 by means of Meissner fraction measurements. A pronounced PE on lambda_{ab}^{-2}(0) was observed with a maximum relative shift of \Delta\lambda^{-2}_{ab}/\lambda^{-2}_{ab}= 44(3)% at a pressure of 10.2 kbar. It arises from the pressure dependence of the effective in-plane charge carrier mass and pressure induced charge carrier transfer from the CuO chains to the superconducting CuO_2 planes. The present results imply that the charge carriers in YBa_2Cu_4O_8 are coupled to the lattice.Comment: 4pages 3 figure

4-Hydroxy-3-nitro-1,4-dihydrotriazolo[5,1-c][1,2,4]triazines: synthesis, antiviral activity, and electrochemical characteristics

A new method for preparation of 4-hydroxy-3-nitro-1,4-dihydrotriazolo[5,1-c][1,2,4]-triazines using 1-nitro-2-morpholinoethylene and 3-diazo-1,2,4-triazoles is proposed. Antiviral activity against the Coxsackie B3 virus and electrochemical transformations of the prepared compounds are studied. © 2022, Springer Science+Business Media LLC.Russian Science Foundation, RSF, (20-13-00142)This work was performed under financial support of the Russian Science Foundation (Project No. 20-13-00142)

SYSTEM OF ANAESTHETIC SUPPORT AT LARGE JOINT REPLACEMENT SURGERIES

The operation of total endoprosthesis replacement of large joints is associated with several anesthetic problems. Solving these problems ensures the safety of these highly traumatic operations and requires the solution of the following anesthetic tasks in the perioperative period: high degree of antinociceptive protection of patients with effective relaxation of the surgical intervention area; prevention of fatty hyperglobulinemia; decrease in the volume of perioperative hemorrhage and prophylaxis of thrombogenic complications. We developed our own program of anesthetic maintenance at major joints replacement. The components of the program are: the type of anesthesia - spinal anesthesia preservation of spontaneous respiration; our method of fat globulinemia prevention, based on maintaining the functional stability of the hepatocyte; our own method of replacement of peri-operative blood loss, based on the additional principle of "normalization of the oncotic blood pressure". Before the operation, patients receive a solution of tranexamic acid at a dose of 10 mg/kg of body mass to inhibit proteolysis (blood preservation technology). This method provides a "dry" operating field, reducing intraoperative hemorrhage. In the early postoperative period (5 hours after the surgery), under the control of whole blood clotting time, patients receive low molecular weight heparin Clexane at a therapeutic dosage of 1 mg/kg of body weight. This provides effective prevention of thrombogenic complications. The application of the developed technique shows its high clinical effectiveness. Over the past 5 years, 5,800 operations for large joint prosthetics have been performed, including 3,200 total hip replacement operations, 2,600 total knee replacement operations. There were no complications with a fatal outcome, in 5 cases fatty hyperglobulinemia was noted, which was stopped by the own method of treatment. There are no thrombogenic complications

A combined theoretical and experimental study of the phase coexistence and morphotropic boundaries in ferroelectric-antiferroelectric-antiferrodistortive multiferroics

The physical nature of the ferroelectric (FE), ferrielectric (FEI) and antiferroelectric (AFE) phases, their coexistence and spatial distributions underpins the functionality of antiferrodistortive (AFD) multiferroics in the vicinity of morphotropic phase transitions. Using Landau-Ginzburg-Devonshire (LGD) phenomenology and a semi-microscopic four sublattice model (FSM), we explore the behavior of different AFE, FEI, and FE long-range orderings and their coexistence at the morphotropic phase boundaries in FE-AFE-AFD multiferroics. These theoretical predictions are compared with the experimental observations for dense Bi1-yRyFeO3 ceramics, where R is Sm or La atoms with the fraction 0 ≤ y ≤ 0.25, as confirmed by the X-ray diffraction (XRD) and Piezoresponse Force Microscopy (PFM). These complementary measurements were used to study the macroscopic and nanoscopic transformation of the crystal structure with doping. The comparison of the measured and calculated AFE/FE phase fractions demonstrate that the LGD-FSM approach well describes the experimental results obtained by XRD and PFM for Bi1-yRyFeO3. Hence, this combined theoretical and experimental approach provides further insight into the origin of the morphotropic boundaries and coexisting FE and AFE states in model rare-earth doped multiferroics. © 2021Authors acknowledge Dr. Bobby Sumpter (ORNL) and Reviewers for very useful suggestions and ideas. This material is based upon work (S.V.K.) supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, and performed at the Center for Nanophase Materials Sciences, a US Department of Energy Office of Science User Facility. A portion of FEM was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility (CNMS Proposal ID: 257). A.N.M. work is supported by the National Academy of Sciences of Ukraine (the Target Program of Basic Research of the National Academy of Sciences of Ukraine "Prospective basic research and innovative development of nanomaterials and nanotechnologies for 2020 - 2024″, Project № 1/20-Н, state registration number: 0120U102306). A.N.M., D.V.K., A.D.Y., O.M.F., T.S., V.V.S. and A.L.K. received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778070. A.N.M. acknowledges the National Research Foundation of Ukraine. M.V.S. acknowledges financial support from the Ministry of Science and Higher Education of the Russian Federation within the framework of state support for the creation and development of World-Class Research Centers "Digital biodesign and personalized healthcare" №075–15–2020–926. Part of the work (A.L.K.) was supported by the Ministry of Education and Science of the Russian Federation in the framework of the Increase Competitiveness Program of NUST «MISiS» (No. K2–2019–015). V.V.S. and A.L.K. were additionally supported by RFBR and BRFBR, project numbers 20–58–0061 and T20R-359, respectively. Part of this work (A.L.K.) was developed within the scope of the project CICECO-Aveiro Institute of Materials, refs. UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the FCT/MCTES