http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Research on the Inter-harmonics Equivalent Impedance of Series Hybrid Active Power Filter
Jian-gong, Zhang,Jian-ben, Liu,Shao-jun, Dai,Qiao-fu, Chen,Jun-jia, He The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.5
In the series hybrid active power filter (SHAPF) with magnetic flux compensation (MFC), the system current oscillate in the experimental results when adding the same phase harmonic current command in current control block. This condition endangers the security of the SHAPF. Taking the digit period average arithmetic as example, this paper explains the inter-harmonics current oscillation in the experiment. The conclusion is that the SHAPF is unstable to the inter-harmonics current in theory. Limited by the capacity of the inverter, the system current and the inverter output current do not increase to infinite. At last, some methods are proposed to solve this problem. From the practical viewpoint, the voltage feed-forward control is easy to achieve. It can suppress the current oscillation problems, and also improve the filtering effect. The feasibility of the methods is validated by both the emulation and experiment results.
Jian-chao Wu,Yu-ting Zheng,Yi-jun Dai 대한치과교정학회 2020 대한치과교정학회지 Vol.50 No.2
Moving the mandibular posterior teeth into a severely atrophic edentulous space is a challenge. A carefully designed force-and-moment system that results in bodily protraction of the posterior teeth with balanced bone resorption and apposition is needed in such cases. This report describes the treatment of a 19-year-old woman with missing mandibular first molars due to juvenile periodontitis. Miniscrews were used as absolute anchorage during protraction of the mandibular second and third molars. Bodily mesial movement of the mandibular second and third molars was achieved over a distance of 11 to 17 mm after 39 months of orthodontic treatment. [Korean J Orthod 2020;50(2):145-154]
Method for Group Decision-Making of Multi-Stakeholders with Category Preference on Alternatives
Dai Quan-chen,Zhu Jian-jun,Zhang Shi-tao 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.8
This paper studies the issue of decision making on some alternatives with category preference of multiple decision makers in which interest conflicts exist and the weights are unknown. It puts forward the method to firstly calculate the attribute weight in each decision maker’s circumstance through case-based learning and thus meet subjective preferences of different decision makers. Considering the interest conflicts between multiple decision makers, the fuzzy set theory is then used to optimize the weight of each decision makers to comply with objective requirements of group decision-making process. Finally, the total order relation of the alternative which does not only conform to the subjective preference information of the decision maker but also consist with the objective fact of group decision-making is obtained based on the calculation result of overall off-target distance for the alternative. The case indicates application procedures and method feasibility.
Jian-Guo Dai,Kent A. Harries,Hiroshi Yokota 국제구조공학회 2008 Steel and Composite Structures, An International J Vol.8 No.6
Yielding of the internal steel reinforcement is an important mechanism that influences the Intermediate Crack-induced debonding (IC debonding) behavior in FRP-strengthened RC members since the FRP is required to carry additional forces beyond the condition of steel yielding. However, rational design practice dictates an appropriate limit state is defined when steel yielding is assured prior to FRP debonding. This paper proposes a criterion which correlates the occurrence of IC debonding to the formulation of a critical steel yielding length. Once this length is exceeded the average bond stress in the FRP/concrete interface exceeds its threshold value, which proves to correlate with the average bond resistance in an FRP/concrete joint under simple shear loading. This proposed IC debonding concept is based on traditional sections analysis which is conventionally applied in design practice. Hence complex bond stress-slip analyses are avoided. Furthermore, the proposed model incorporates not only the bond properties of FRP/concrete interface but also the beam geometry, and properties of steel and FRP reinforcement in the analysis of IC debonding strength. Based upon a solid database, the validity of the proposed simple IC debonding criterion is demonstrated.
Dai Jian-Qing,Yuan Jin 한국물리학회 2021 Current Applied Physics Vol.29 No.-
In this work, we report on the structural, electronic, and ferroelectric properties of SmMn2O5 by using firstprinciples density functional theory plus on-site Coulomb interaction (DFT + U) calculations. A thorough analysis was preformed to reveal the competing characteristics of different high-temperature (T) phases and the polarization mechanism in the low-T multiferroic phase. We show that the structural characteristics of the high-T phases have a strong influence on the low-T multiferroicity. In addition to the spin-induced lattice distortion that reduces substantially the purely electronic ferroelectricity, the dominant polarization mechanism in low-T SmMn2O5 still originates from the electronic polarization. By performing mode decomposition of the Hellmann– Feynman forces and the lattice distortion induced by the q = (0.5, 0, 0) magnetic order, we find that the Raman-active Ag mode characterized by the Mn4+O6 octahedron distortion and synergistic displacement of Mn3+ and Sm ions is of primary importance, while the infrared (IR)-active B2u mode plays a secondary role. These findings provide a theoretical foundation for future studies concerning the enhanced magnetoelectric effects of SmMn2O5 due to its pure exchange–striction mechanism.
A New Ferulic Acid Ester and Other Constituents from Dracocephalum peregrinum
Dai, Li-Min,Zhao, Chun-Chao,Jin, Hui-Zi,Tang, Jian,Shen, Yun-Heng,Li, Hui-Liang,Peng, Cai-Yon,Zhang, Wei-Dong 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.10
A new ferulic acid ester, 1'-methyl-2'-hydroxyethyl ferulate (1), together with methylcaffeate (2), 4-hydroxy cinnamic acid (3), ferulic acid (4), caffeic acid (5), diosmetin (6), luteolin (7), 5,3',4'-trihydroxy-3,7-dimethoxyflavone (8), eriodictyol (9), kaempferol (10), quercetin (11), acacetin-7-O-glcopyranoside (12), 4-($\beta$-glucopyranosyloxy) benzoic acid (13), luteolin-7-O-(6"-feruloyl) glucopyranoside (14), luteolin-7-O-glucopyranoside (15), kaempferide-3-O-rhamnopyranoside (16), quercitrin (17), kaempferol-3-O-glucopyranoside (18), prunasin (19), quercetin-7-O-glucopyranoside (20), quercetin-3-O-glucopyranoside (21), plantaginin (22), linarin (23), luteolin-7-O-rutinoside (24), and chlorogenic acid (25) were isolated from the aerial parts of Dacocephalum peregrinum. The structure of 1 was elucidated on the basis of spectroscopic and HR-ESI-MS analyses. In addition, compound 1 exhibited mild inhibitory effect on NO production in LPS-stimulated RAW264.7 cells.
Cooperative Relaying with Interference Cancellation for Secondary Spectrum Access
( Zeyang Dai ),( Jian Liu ),( Keping Long ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.10
Although underlay spectrum sharing has been shown as a promising technique to promote the spectrum utilization in cognitive radio networks (CRNs), it may suffer bad secondary performance due to the strict power constraints imposed at secondary systems and the interference from primary systems. In this paper, we propose a two-phase based cooperative transmission protocol with the interference cancellation (IC) and best-relay selection to improve the secondary performance in underlay models under stringent power constraints while ensuring the primary quality-of-service (QoS). In the proposed protocol, IC is employed at both the secondary relays and the secondary destination, where the IC-based best-relay selection and cooperative relaying schemes are well developed to reduce the interference from primary systems. The closed-form expression of secondary outage probability is derived for the proposed protocol over Rayleigh fading channels. Simulation results show that, with a guaranteed primary outage probability, the proposed protocol can achieve not only lower secondary outage probability but also higher secondary diversity order than the traditional underlay case.