• Title/Summary/Keyword: Hearing and Frequency Measurements

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Development of a Multi-Layer Actuator With Piezoelectric Single Crystals for an Implantable Hearing Aid (압전 단결정 재료를 이용한 이식형 인공중이용 적층 액츄에이터 개발)

  • Lee, Sang-gu;Roh, Yong-rae;Seon, Joo-heon
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.3
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    • pp.127-132
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    • 2005
  • Transducers for implantable hearing aids need to be small and to have good performance in frequency responses and vibration properties. From this viewpoint, we Proposed a multi-layer actuator with the piezoelectric single crystal, PMN-PT. for the implantable hearing aid. and verified its adequacy through finite element analyses and experiments. PMN-PT multi-layer actuator samples were fabricated by stacking fourteen layers of the PMN-PT crystal. Each layer were $0.2{\cal}mm$ thick and the actuator sample was $2.8{\cal}mm$ thick in total. We evaluated the performance of the PMN-PT actuator through impedance analyses and vibration displacement measurements, and compared the result with that of a PZT actuator. Results of all the process confirmed the feasibility of the PMN-PT actuator as a good transducer for an implantable hearing aid.

Investigation on Influencing Environmental Factors on Health Status of Korean Septuagenarians Dwelling in Longevity Region in Jeonla Province (전라도 농촌장수지역 거주 70대 노인의 건강상태에 영향을 미치는 환경적 요인에 대한 탐색 연구)

  • Kwak, Chung Shil;Yon, Miyong;Lee, Mee Sook;Oh, Se In;Park, Sang Chul
    • Korean Journal of Community Nutrition
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    • v.19 no.2
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    • pp.142-162
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    • 2014
  • Objectives: To evaluate the critical environmental factors on healthy-aging of Korean people, we investigated the significant factors influencing health status of septuagenarians living in rural area of Jeonla province, known to be one of the representative longevity regions in Korea. Methods: We divided subjects into healthy group (36M/25F) or poor-health group (26M/73F) based on self-reported health status, body mass index, a number of prescription, and blood test data. General characteristics, physical measurements, lifestyle, dietary behavior and nutrient intake, physical health and mental health data were statistically compared between the two groups. Results: Average age was not different between healthy group and poor-health group in men and women, respectively. In men, significantly favorable factors to health were observed to be higher education, regular exercise, higher grip strength and walking function, body mass index (${\geq}18.5kg/m^2$), moderate frequency of drinking and eating-out, non-smoking, normal red blood cell (RBC) count, higher serum dehydroepiandrosterone-sulfate (DHEAS) level, good digestive function and appetite, normal hearing function, regular meals, adequate vegetable and fruit intake, diverse food intake, adequate energy and nutrients (protein, vitamin $B_1$, $B_6$, C and E, folate, niacin, P, Zn and K) intake, higher mini-nutrient status assessment (MNA) score and low level of depression. On the other hand, in women, those were literacy, living arrangement, moderate frequency of drinking, healthy teeth, higher grip strength and walking function, bone mineral density, normal RBC and white blood cell (WBC) count, higher DHEAS concentration, higher MNA score, normal cognition and memory function, having snack and adequate fruit intake. Conclusions: These results could be useful to plan effective strategies to increase health-life expectancy of Korean old people living in rural areas.