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Power supply for generating frequency-variable resonant magnetic perturbations on the J-TEXT tokamak
To further research the response of the tearing mode(TM) to dynamic resonant magnetic perturbation(DRMP) on the J-TEXT tokamak, a modified series resonant inverter power supply(MSRIPS) with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor(IGBT) full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier(SCR) switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak. 相似文献
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根据无线信号传播方式的特殊性,重新定义了无线组播路由中的代价和时延函数,基于图论中最小连通支配集(MCDS)理论,提出的基于图论中点着色思想的时延定界组播转发结构的构建方法,通过求解MCDS来实现构建最小代价组播路由结构的目的,提出了组播路由时延定界的概念,并在该约束下构建MCDS。理论推导证明了该算法的正确性,与同类算法相比,较低的近似比证明了该算法的有效性,同时具有O(n)的时间复杂度和O(n)的消息复杂度,进一步证明了其高效性,具有适应于灵活多变的Ad hoc网络的优势。 相似文献
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十八胺作为最常用的浮选剂用于世界上75%的氯化钾生产.十八胺不仅会污染环境,而且对氯化钾的工业生产和食品级使用都会产生影响.因此,对十八胺的检测势在必行,采用气相色谱法可以快速测定氯化钾中十八胺的有效含量.试验所得标准曲线线性良好,相关系数为0.999 2. 相似文献
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文化之河犹如一个民族的血脉。古往今来,世界任何民族生生不息的真正不竭动力就是她的独特文化。而作为将文化不断传承的载体,人的品格和情操也随着他们所传承的文化那样,一同在历史中飘然流淌,被后世所品读。《一代名士张伯驹》把湮灭在历史烟云中的这位名士挖掘了出来,生动地再现了张伯驹所经历的那个跌宕起伏的时代。品读全书,我完全可以 相似文献