标准模型中D0-D0bar混合效应非常小，其混合研究对标准模型的精确检验，寻找新物理具有重要意义。目前没有在单一D0三体衰变过程发现混合，通过单一D0衰变过程发现D0-D0bar混合是各个实验组的热门课题和重要任务。我们根据Belle合作组数据和Belle II合作组计划采集数据，通过D0三体衰变D0->Kspi+pi-，D0->KsK+K-和D0->K+pi-pi0做达利兹分析测量混合参数和研究CP破坏效应，测量D0->Ks pi0 eta中CP不对称性。核子的电磁形状因子是理解核子结构的重要物理量，也可以检验各种理论计算。目前类空过程的实验数据精度较高，类时过程的实验精度较差。根据Belle现有数据，通过初态辐射方法测量核子-反核子对产生截面和电磁形状因子，研究其随能量的演化关系，特别是在核子对阈值附近的行为。提供较高精度的实验数据，检验各种理论模型。

The mixing rate and CP violation in D0-D0bar are expected to be very small in Standard Model, hence, they are sensitive to contribution from physics beyond Standard Model. The experimental data consistently indicate that D0 undergo mixing, however, there is no observation in tree body D0 decay from a single measurement. For collected data by Belle Collaboration and possible data by Belle II Collaboration, the Dalitz analysis is performed for D0->Kspi+pi-,D0->KsK+K- and D0->K+pi-pi0, to extract mixing parameters with higher precision. The CP assymmetry in D0->Ks pi0 eta is also studied with Dalitz analysis. The electromagnetic form factors of nucleon play an important role on understanding of nucleon structure. The form factors could be extracted in timelike region and spacelike region, in former case, data points are scarce and less precision. The initial state radiation technology is applied to extract nucleon anti-nucleon cross section, and nucleon form factor from its threshold up to 4.5GeV at Belle. More precise results are expected to test theory phenomenal models.