The molecular second-order nonlinear optical (NLO) properties and the powder second harmonic generation(SHG)of semicarbazide hydrochloride were studied.The molecular and crystal structure dependence of second-order nonlinearity,transparency and thermal stability was discussed.It was also implied that semicarbazide hydrochloride as an ionic compound played important roles in designing effective second-order NLO materials.
A new kind of second order nonlinear optical(NLO) material m hydroxybenzoic acid(HBA) was reported in this paper. Primary study results revealed that it had a relatively strong nonlinearity, its powder SHG effect was 12 times that of KDP. The solid cut off wavelength λ cut off (350 nm) is very short compared to other organic second order NLO materials. The experimental results also showed that HBA had a high laser damage threshold and good characteristic thermal stability. Furthermore, We calculated its second order nonlinear hyperpolarizability β and analyzed the microscopic nonlinear properties, and found that the hydroxyl group could improve β obviously while the hydroxyl multisubstitution could hardly contribute to β values. [WT5HZ]
生物分子在材料表面的吸附行为对于许多领域的研究具有重要意义,分子模拟能提供实验上无法获得的重要分子层次的信息.该文采用Materials Studio 4.4软件包,Adsorption模块,Universal力场,分别在真空与水环境下模拟研究了TiO2锐钛矿和金红石两种晶体材料表面吸附人血纤肽片段(HFG)的行为,并研究了不同电荷HFG的影响.结果表明:真空中带负电的HFG与金红石结合较稳定;水的介入,明显的影响了HFG在TiO2表面的吸附行为,尤其对锐钛矿影响更大;如果材料上带有负电荷,那将会大大提高它的抗凝血性能.
