Ground-state phase diagram of the dimerizedspin-1/2 two-leg ladder

Dimerized spin-1/2 ladders exhibit a variety of phase structures, which depend on the intra-chain and inter-chain spin exchange energies as well as on the dimerization pattern of the ladder. Using the density matrix renormalization group (DMRG) algorithm, we study critical properties of the bond-alternating two-leg Heisenberg spin ladder with diagonal interaction J_×. Two types of spin systems, staggered dimerized antiferromagnetic ladder and columnar dimerized ferro-antiferromagnetic couplings ladder, are investigated. To clarify the phase transition behaviors, we simultaneously analyze the string order parameter (SOP), the twisted order parameter (TOP), as well as a measurement of the quantum information analysis. Based on measuring this different observables, we establish the phase diagram accurately and give the fitting functions of the phase boundaries. In addition, the phase transition of cross-coupled spin ladder (in the absence of intrinsic dimerization) is also discussed.     

悬浮聚合法制备西咪替丁印迹聚合物微球的分子选择性能

以西咪替丁为印迹分子，2-丙烯酰胺-2-甲基丙磺酸(AMPS)为功能单体，三羟甲基丙烷三甲基丙烯酸甲酯(TRIM)为交联剂，采用悬浮聚合法制备得到了平均粒径在60-310μm之间的分子印迹聚合物微球(MIPMS)，将所得的MIPMS用作固相萃取剂(SPE)的测试结果表明，该MIPMS对西咪替丁有较好的特异选择性能，当以苯丙氨酸为竞争分子时，分离因子可达1．75，且该MIPMS呈现出较好的再生性。而未印迹的空白聚合物则无此分子选择性。