带分布时滞的双向联想记忆神经网络周期解的存在性

讨论了-类带分布时滞的双向联想记忆神经网络周期解的存在性.通过运用Mawhin迭合度连续性定理,和-些不等式的分析技巧,得到了-些保证周期解存在的充分条件.     

超声参数联合血清OPN、IL-1β对乳腺癌的临床诊断价值研究

选取我院收治的乳腺癌(BC)患者82例设为研究组,同期乳腺良性肿瘤患者82例设为对照组,探讨了超声参数联合血清骨桥蛋白(OPN)、白细胞介素-1β(IL-1β)对BC的诊断价值.结果显示,研究组患者病灶处的RI值、PI值和血清OPN、IL-1β水平均高于对照组(P＜0.05);PI值、RI值、血清OPN、IL-1β水平...     

Crystal Structure,Photoluminescence, and Theoretical Studies of Dihydropyran Derivatives

Two novel dihydropyran compounds(1 and 2) containing a triphenylamine group were synthesized and characterized. The structure of compound 2 was verified by single-crystal X-ray crystallography. It crystallizes in triclinic, space group P1 with a = 6.9943(4), b = 8.1360(4), c = 23.9274(14) , α = 87.692(4), β = 88.940(5), γ = 85.223(4)o, V = 1355.62(13) 3, Z = 2, F(000) = 520, Dc = 1.199 Mg/m3, Mr = 489.24 and μ = 0.075 mm-1. The UV-vis absorption and fluorescence of the two compounds were discussed. The two compounds exhibited strong blue emissions under ultraviolet light excitation. The molecular structure and HOMO and LUMO levels of compound 2 were calculated by density functional theory(DFT) at the B3LYP/6-31G(d) level.