Turn-on fluorescent optical probing polypyrimidine: Efficient detecting method for Hg2+

The fluorescence of conjugated pyrimidine containing polymer P1 [poly(2,5-dido decyloxy-1,4-diethynyl phenylene-alt-2-amino-4,6-pyrimidine) and P2 [poly(2,5-dido decyloxy-1,4-diethynyl phenylene-alt-2-N,N-dimethylamino-4,6-pyrimidine) solution (Tetrahydrofuran) was gradually quenched with the increasing concentration of I– (KI, in water solution) and followed with color change from transparent to yellow. The fluorescence was gradually recovered via adding of Mercury ion (Hg2+) accompanied color change from yellow to colorless since the existing high binding constants and complexation ratio between Hg2+and I- . The presence of background metal cations which has weak interference for Hg2+ optical response. The experimental results reveal that polymers were kind of Hg2+ turn-on optical probe with high sensitivity and anti-interference.

Symmetry and Asymmetry in Quasicrystals or Amorphous Materials

Quasicrystals (QCs) are long-range ordered materials with a symmetry incompatible with translation invariance. Accordingly, QCs exhibit high-quality diffraction patterns containing a collection of discrete Bragg reflections. Notwithstanding this, it is still common to read in the recent literature that these materials occupy an intermediate position between amorphous materials and periodic crystals. This misleading terminology can be understood as probably arising from the use of models and notions borrowed from the amorphous solid’s conceptual framework (such us tunneling states, weak interference effects, variable range hopping, or spin glass) in order to explain certain physical properties observed in QCs. On the other hand, the absence of a general, full-fledged theory of quasiperiodic systems certainly makes it difficult to clearly distinguish the features related to short-range order atomic arrangements from those stemming from long-range order correlations.

Analysis and Research on the Structure Selection of BeiDou Navigation Array Antenna Based on Optimized PI Algorithm

To overcome the disadvantages of the traditional power inversion algorithm, which has obvious suppression effect on strong interference signals but unobvious effect on suppression of weak interference signals, a matrix decomposition method is proposed to extract the interference sub-matrix and noise sub-matrix, so that the power inversion algorithm can be adopted to weaken and filter out the signals in the case of weak interference. Through the optimized power inversion algorithm, the interference signal can be weakened obviously at the antenna receiving end, and the quality of the effective signal received by the antenna can be improved significantly. Afterwards, the algorithm was used to carry out MATLAB simulation in space based on the anti-jamming performance of different array models, which determined the anti-jamming antenna array structure as a uniform matrix and optimized the array structure. The simulation results show that the optimized power inversion algorithm can filter strong and weak interference better, and the anti-jamming performance is better under different array models and two kinds of interferences. Through comparative analysis, it is concluded that the four elements have the best interference suppression effect in uniform circular array structure, which provides an important reference for the selection of antenna array in adaptive interference suppression hardware structure. At the same time, the BeiDou four-element adaptive circular array antenna, as an important part of intelligent geological disaster monitoring and early warning system, has good anti-jamming ability.