... ,it has a high degree of preservation . 4, acid resistant refractory: the thermal conductivityof paulownia is small, generally the wood burning ... a stable tone, thus is how "Qin Tong" known. The board of the dulcimer, pipa, Qin Hu and Liuqin are all ... &backs,finger jointed boards,coffin boards,princess and room partition board and so on.It also has the advantages of impenetrable ...