Thermal conductivity investigation of large grain niobium material used for fabrication of SRF cavities, Jia-er Chen, Superradiant THz undulator radiation source based on a superconducting photo-injector Ultrafast electron diffraction with megahertz MeV electron pulses from a superconducting radio-frequency photoinjector, Kui Zhao, Jiaer Chen, Stable operation of the DC-SRF photoinjector, Nucl. Instrum. Development of DC-SRF Injector at Peking University, 6th International Particle Accelerator Conference, 国际直线对撞机(ILC)高梯度射频超导加速腔研制， 16th International Conference on RF Superconductivity, Improving Gradient of 9-cell SRF Cavities at Peking University, Cold RF test and associated mechanical features correlation of a TESLA-style 9-cell superconducting niobium cavity built in China,.Chinese Physics C, 3.5-cell large grain niobium superconducting cavity for a dc superconducting rf photoinjector,