Characterization and antioxidant activity of an acidic exopolysaccharide from Lactobacillus plantarum JLAU103

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砂岩和石灰岩是石油天然气钻井破岩的主要对象，它的物理力学性质已有系统的测定方法和定量分级。但是，它抗喷嘴射流冲蚀破碎的内涵关系和临界压力值还没有定量指标。通过大量的实验研究和综合分析，得出了砂岩、石灰岩和抗压强度与抗喷嘴射流冲蚀破岩压力的临界值在１９．１～２６．９之间。为钻井水力参数的设计提供了可靠数据，同时为开采作业提供了理论依据。     

Crystal structure and infrared spectrum of thallium holmium polyphosphate, TIHo(PO3)4

Crystals of thallium-holmium polyphosphate TIHo(PO3)4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of TIHo(PO3)4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions: a=1.02225(3) nm, b=0.88536(2) nm, c=1.09541(4) nm, β=105.888(1)°, V=0.95354(5) nm3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1(F2)=0.0442 and Rw(F<2)=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eighffold coordination. The structure of T1Ho(PO3)4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350-4000 cm-1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen.