http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Yaowen Li (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Synthesis, characterization and magnetic properties on nanocrystalline BaFe12O19 ferrite
Yaowen Li,Qin Wang,Hua Yang 한국물리학회 2009 Current Applied Physics Vol.9 No.6
Single phase BaM (BaFe12O19) ferrites are prepared by using sol–gel method. The preparing conditions of samples are investigated in detail, such as acid/nitrate ratio, the value of pH and annealing temperature. The best conditions on preparing BaFe12O19, which can be obtained on a Fe/Ba ratio of 12, the citric acid contents R = 3, the starting pH of solution is 9, and annealing temperature 950 ℃. The thermal decomposition behavior of the dried gel was examined by TG–DSC, the structure and properties of powders were measured respectively by XRD techniques. The magnetic properties of barium ferrites are emphatically researched about the changing crystallite size and annealing temperature by the vibrating sample magnetometer (VSM). Magnetic measurement shows that the barium ferrite samples annealed at 1000 ℃ has the maximal coercive field of 5691.91 Oe corresponding to the maximal remnant magnetization of 35.60 emu/g and the sample synthesized at 1000 ℃ has the maximal saturation magnetization of 60.75 emu/g. Single phase BaM (BaFe12O19) ferrites are prepared by using sol–gel method. The preparing conditions of samples are investigated in detail, such as acid/nitrate ratio, the value of pH and annealing temperature. The best conditions on preparing BaFe12O19, which can be obtained on a Fe/Ba ratio of 12, the citric acid contents R = 3, the starting pH of solution is 9, and annealing temperature 950 ℃. The thermal decomposition behavior of the dried gel was examined by TG–DSC, the structure and properties of powders were measured respectively by XRD techniques. The magnetic properties of barium ferrites are emphatically researched about the changing crystallite size and annealing temperature by the vibrating sample magnetometer (VSM). Magnetic measurement shows that the barium ferrite samples annealed at 1000 ℃ has the maximal coercive field of 5691.91 Oe corresponding to the maximal remnant magnetization of 35.60 emu/g and the sample synthesized at 1000 ℃ has the maximal saturation magnetization of 60.75 emu/g.
-
-
Analytical and experimental investigation of stepped piezoelectric energy harvester
Deepesh Upadrashta,Li Xiangyang,Yang Yaowen 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.6
Conventional Piezoelectric Energy Harvesters (CPEH) have been extensively studied for maximizing their electrical output through material selection, geometric and structural optimization, and adoption of efficient interface circuits. In this paper, the performance of Stepped Piezoelectric Energy Harvester (SPEH) under harmonic base excitation is studied analytically, numerically and experimentally. The motivation is to compare the energy harvesting performance of CPEH and SPEHs with the same characteristics (resonant frequency). The results of this study challenge the notion of achieving higher voltage and power output through incorporation of geometric discontinuities such as step sections in the harvester beams. A CPEH consists of substrate material with a patch of piezoelectric material bonded over it and a tip mass at the free end to tune the resonant frequency. A SPEH is designed by introducing a step section near the root of substrate beam to induce higher dynamic strain for maximizing the electrical output. The incorporation of step section reduces the stiffness and consequently, a lower tip mass is used with SPEH to match the resonant frequency to that of CPEH. Moreover, the electromechanical coupling coefficient, forcing function and damping are significantly influenced because of the inclusion of step section, which consequently affects harvester's output. Three different configurations of SPEHs characterized by the same resonant frequency as that of CPEH are designed and analyzed using linear electromechanical model and their performances are compared. The variation of strain on the harvester beams is obtained using finite element analysis. The prototypes of CPEH and SPEHs are fabricated and experimentally tested. It is shown that the power output from SPEHs is lower than the CPEH. When the prototypes with resonant frequencies in the range of 56-56.5 Hz are tested at 1 m/s<sup>2</sup>, three SPEHs generate power output of 482 μW, 424 μW and 228 μW when compared with 674 μW from CPEH. It is concluded that the advantage of increasing dynamic strain using step section is negated by increase in damping and decrease in forcing function. However, SPEHs show slightly better performance in terms of specific power and thus making them suitable for practical scenarios where the ratio of power to system mass is critical.
-
Research on Forecasting Electricity Demand of the 13th Five-year in Hebei Province
Huiru Zhao,Nana Li,Yaowen Fan,Fuqiang Li,Yuou Hu 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.11
With the emergence of a “new economic norm” and “industrial restructuring”, the electricity demand situation in Hebei province will undergo significant changes in the future. Therefore, it is essential to predict electricity demand in the 13th Five-year for power planning and construction. Considering the factors and mechanisms determining electricity demand of various sectors are different, the total electricity consumption in this paper is divided into five parts: the first industry, industry, construction, the tertiary industry and resident sectors. The electricity demand equations of different sectors are established to make predictions, respectively. The results show that the total electricity consumption will grow at an annual rate of 3.46%-3.87% during 13th Five-Year-Plan period, which would be more than 0.4234×1012 kWh in 2020. The electricity consumption growth of tertiary industry and resident sectors would raise fast, which will grow at an annual rate of 8.72%-9.15% and 6.24%-6.72% during 13th Five-Year-Plan period. Moreover, comparing with the demand structure in 13th Five-Year-Plan period, the proportion for industrial electricity demand will decline by 5%, the proportions for tertiary industry and resident sector will increase by 3% and 2%. The electricity consumption structure in Hebei province would change in the future.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
