18 research outputs found

    Use of anticoagulants and antiplatelet agents in stable outpatients with coronary artery disease and atrial fibrillation. International CLARIFY registry

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    Formation of Crystal Structure in Dielectric BaAl2Si2O8BaAl_2Si_2O_8-Based Materials Depending on Preparation Conditions

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    Crystal structure formation of BaAl2Si2O8BaAl_2Si_2O_8 known as polymorphic compound is investigated in present work depending on conditions of preparation. Characteristics of ceramics have been studied for different modifications of crystal structure. Additional technologic operations (grinding with following heat treatment) have been found to result in polymorphic transformation. Dielectric properties of BaAl2Si2O8BaAl_2Si_2O_8 ceramics have been studied for hexagonal, monoclinic crystal structure modifications as well as for that based on phase mixture. It has been shown that the sintering of ceramic material based on the monoclinic crystal structure modification of BaAl2Si2O8BaAl_2Si_2O_8 takes place in temperature diapason of 1300-1350°C. Sintering of material with the hexagonal crystal structure modification occurs in temperature diapason of 1450-1500°C. Ceramics materials based on compound BaAl2Si2O8BaAl_2Si_2O_8 are found to have low porosity, high Q-factor and dielectric characteristics, allowing use of these ceramic materials for production of resonators and other microwave equipments

    Influence of ultrasonic mechanoactivation on phase formation in dielectric ceramic material based on BaAl2Si2O8

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    Mechanoactivation effect has been studied on crystal structure of BaAl2Si2O8 known as polymorphous compound. Ultrasonic treatment of the synthesized material powder has been used as mechanoactivation method. Ultrasonic grinding during 0.5–1.5 h was determined to result in polymorphous transformation. Dielectric properties of ceramics BaAl2Si2O8 have been investigated for hexagonal, monoclinic modifications of crystal structure as well for that based on phase mixture. It is shown that sintering of ceramic material based on monoclinic crystal structure modification of BaAl2Si2O8 takes place in temperature diapason of 1300– 1350ÂșĐĄ. Ceramic materials based on BaAl2Si2O8 compounds have been shown to exhibit low porosity, high Q-factor and dielectric parameters allowing use them for resonators, and other microwave devices
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