Strategy of the warring states period is the main material origin concerning the warring states period in historical records , about which sima qian , according to his writing purpose and criterion of compiling history , adopted methods of copying almost completely , summarizing and rewriting , which made the events scattered in historical records be in better order , smoother and concise , as a result , become reasonable and true historical materials 摘要《战国策》是《史记》中战国部分的主要资料来源，司马迁根据行文的需要和纂史的标准，对其采取了基本全录、概括改写等方法，使杂散于《战国策》中事件，更加条理、通顺、简洁，使之成为较为合理真实的史料。
On the base of analysis of the svpwm controller for two - phase asynchronous motors in home and abroad , the svpwm technique by using four space voltage vectors and divided eight sectors is advanced . the controller parameter and formulation are deduced . an optimized modulation index is proposed for the motor having rotary circle magnetic field 论文在分析国内外两相逆变器异步电动机的svpwm控制基础上，提出四个电压矢量八个工作空间的svpwm控制技术，推导了控制参数和计算公式，提出了使电机具有圆形旋转磁场的调制比优化方案，给出了实施本方案的逆变器功率管的导通顺序和逆变器的输出电压波形。
