ABSTRACT
Ferroelectric, phase-change, and magnetic materials are considered promising candidates for advanced memory devices. Under the development dilemma of traditional silicon-based memory devices, ferroelectric materials stand out due to their unique polarization properties and diverse manufacturing techniques. On the occasion of the 100th anniversary of the birth of ferroelectricity, scandium-doped aluminum nitride, which is a different wurtzite structure, was reported to be ferroelectric with a larger coercive, remanent polarization, curie temperature, and a more stable ferroelectric phase. The inherent advantages have attracted widespread attention, promising better performance when used as data storage materials and better meeting the needs of the development of the information age. In this paper, we start from the characteristics and development history of ferroelectric materials, mainly focusing on the characteristics, preparation, and applications in memory devices of ferroelectric wurtzite AlScN. It compares and analyzes the unique advantages of AlScN-based memory devices, aiming to lay a theoretical foundation for the development of advanced memory devices in the future.
ABSTRACT
PURPOSE: To investigate the current status of dental caries and periodontal diseases in the population aged 35-44 and 65-74 years in Jiangxi province, and to provide information for prevention of these diseases. METHODS: 1584 people (aged 35-44 and 65-74 years) were selected by equal-sized stratified multi- stage and random sampling. Their dental caries and periodontal diseases were examined in routine epidemiologic surgery manner. Student's t test and Chi-square test were applied for statistical analysis using SPSS12.0 software package. RESULTS: In the age group of 35-44 and 65-74 years, the prevalence rate of dental caries was 59.4% and 85.5%, the mean DMFT was 2.19 and 4.91, the prevalence rate of root caries was 32.7% and 79.5%, the mean DFRoot was 0.28 and 1.25,the rate of healthy periodontal tissues was 0.1% and 5.3%. CONCLUSIONS: Dental caries and periodontal diseases are quite common diseases in Jiangxi Province. We should reinforce the oral health care and the propaganda for oral care knowledge in order to treat caries and periodontal diseases better and earlier, and improve the life quality of middle-aged and elderly citizens.
