http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Elucidating synthesis of noble metal nanoparticles/graphene oxide in freescavenger γ-irradiation
Jie Shi,Wanwei Jiang,Liangsen Liu,Miaolei Jing,Fengyan Li,Zhiwei Xu,Xing-xiang Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.7
Three representative noble metal (Ag, Au and Pt) nanoparticles decorated graphene oxide (NMNPs/GO) composites were fabricated via γ-irradiation without scavenger. The NMNPs/GO composites exhibited the pure and well-dispersed particles structure, which directly illustrated that the GO could be acted as scavenger to benefit reduction and growth of NMNPs. Compared with irradiated GO (IGO), the GO substrate of composites had the lower relative content of hydroxyl groups, meanwhile, the relative contents of carbonyl groups (Pt > Au > Ag) were increased with increasing valence of noble metal. Such results illustrated that the abundant hydroxyl groups could convert the hydrated electrons, hydroxyl and hydrogen radicals to promote the growth of NMNPs on the surface of GO. In addition, the Raman signals of Ag NPs/GO composites were significantly enhanced (6.18 fold more than pristine GO, respectively), exhibiting obvious surface-enhanced Raman scattering activity. Therefore, this paper revealed that the GO could convert the hydrated electrons and radicals to synthetizing NMNPs/GO composites during γ-ray irradiation.
Analysis and Compensation Control of Dead-Time Effect on Space Vector PWM
Jie Shi,Shihua Li 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
Dead-time element must be set into space vector pulsed width modulation signals to avoid short circuits of the inverter. However, the dead-time element distorts the output voltage vector, which deteriorates the performance of electrical machine drive system. In this paper, dead-time effect and its compensation control strategy are analyzed. Based on the analysis, the voltage distortion caused by dead-time is regarded as two disturbances imposed on dq axes in the rotor reference frame, which degenerates the current tracking performance. To inhibit the adverse effect caused by the dead-time, a control scheme using two linear extended state observers is proposed. This method provides a strong ability to suppress dead-time effects. Simulations and experiments are conducted on a permanent magnet synchronous motor drive system to demonstrate the effectiveness of the proposed method.