Study and design of RF coupler for Chinese ADS HWR superconducting cavity

An RF power coupler is a key component of the superconducting accelerating system in Chinese ADS proton linac injector I, which is used to transmit 15 kW RF power from the power source to the superconducting HWR cavity. According to the requirement of working frequency, power level, transmission capability and cooling condition, the physics design of coupler has been finished, which includes RF structure optimization, thermal simulation, thermal stress analysis and so on. Based on this design, the prototype of HWR coupler has been fabricated, and it has successfully passed the high power test.     

BEPCⅡ正电子环真空度随流强的非线性变化

 观察发现负电子环的真空度随流强呈线性变化,正电子环的真空度随流强呈非线性变化,在正电子环的弧区,真空度的非线性变化很明显。讨论了非线性变化的原因,可能是同步光电子在正电子束流横向作用下加速碰壁,发生了二次电子发射,并在一定条件下形成了束流引起的多次碰壁效应,造成了大量放气。改变正电子束流的束团填充方式来观察真空度的非线性变化,得到了与KEK-B低能环一致的实验结果,该非线性变化呈现一定的阈值性,发生非线性的条件是有足够大的单束团流强和每列足够多的连续束团。     

d-生物素的不对称全合成研究(Ⅱ)

1,3－二苄基咪唑啉－2－酮－顺－4,5－二羟酸经脱水、单酯化,折分成分（4S,5R）－顺1,3－二苄基－5－甲氧基羧基－2－氧代咪唑啉－4－羧酸,再经还原环合,硫代成(3aS,6aR)-1,3－二苄基－四氢－4H－噻吩并[3,4-d)咪唑－2,4（1H)-二酮（7）,后者经格氏反应、脱水、还原、裂解环合一锅合成（3aR,8aS,8bS)－1,3－二苄基－2－氧代十氢咪唑[3,4-d]噻吩并[1,2-a]锍翁溴化物（11）,继而经缩合、开环、水解、脱羧、脱苄而得d－生物素（1）,总收率为14．5％。     

Study and design of RF coupler for Chinese ADS HWR superconducting cavity

An RF power coupler is a key component of the superconducting accelerating system in Chinese ADS proton linac injector I, which is used to transmit 15 kW RF power from the power source to the superconducting HWR cavity. According to the requirement of working frequency, power level, transmission capability and cooling condition, the physics design of coupler has been finished, which includes RF structure optimization, thermal simulation, thermal stress analysis and so on. Based on this design, the prototype of HWR coupler has been fabricated, and it has successfully passed the high power test.     

改进教学方法培养学生良好的学习习惯和创新能力

结合自己的教学实践对概率统计的教学方法进行了探讨,通过实例说明了在概率统计的教学中如何激发学生的学习兴趣,如何培养学生的良好学习习惯和创新能力.