Arsenic Compounds in Zoo- and Phyto-plankton of Marine Origin

Major water-soluble arsenic compounds accumulated in some zoo- and phyto-plankton were identified. Zooplankton were collected at sampling stations in the Sea of Japan by a Norpac net towed from 600 m depth to the surface. Phytoplankton were cultivated under axenic conditions. Water-soluble arsenic compounds were extracted repeatedly from plankton tissues by aqueous methanol. The arsenic compounds in the extracts were analyzed by HPLC–ICP/MS. Among zooplankton analyzed in the present study, two carnivorous species, i.e. Amphipoda ( Themisto sp.) and Sagittoidea ( Sagitta sp.), contained arsenobetaine as the dominant arsenic species. Arsenobetaine was the major species in Euphausiacea ( Euphausia sp.), also. The most abundant arsenic compound in the herbivorous Copepoda species ( Calanus sp.), on the other hand, was an arsenic-containing ribofuranoside with a sulfate ester group, and arsenobetaine was only a minor component. Phytoplankton contained arsenic-containing ribofuranosides apparently in a species-speific manner. The arsenic compounds in zooplankton seem to reflect their feeding habit; i.e. carnivorous species eating zooplankton or other small animals accumulate arsenobetaine, while herbivorous ones eating phytoplankton accumulate arsenic-containing ribofuranosides as major arsenic compounds.     

氧等离子体处理对GaAs表面单层自组装SiO2纳米球薄膜的影响

二维纳米阵列结构因其重要的光学性能被广泛应用于各类光电子器件。本文对自组装单层SiO2纳米球掩模刻蚀法制备GaAs纳米柱二维阵列结构的关键工艺技术进行了研究。采用旋涂法在GaAs表面制备自组装单层SiO2纳米球,重点研究了GaAs表面氧等离子体亲水处理工艺对纳米球排列特性的影响,获得最佳工艺条件为功率配比100 W+80 W、腔室压力4 Pa、氧气流量20 mL/min、处理时间1200 s,并最终得到排列紧密的大面积单层纳米球薄膜。以单层纳米球为掩模,采用感应耦合等离子体刻蚀技术在GaAs表面制备了纳米柱阵列并测试了其表面光反射谱。测试结果表明,GaAs纳米柱阵列在特定波段的反射率降低至5%,远低于表面无纳米结构的薄膜材料表面高达40%的光反射。分析表明纳米柱可以激发米氏散射共振效应,从而有效降低反射率并提升光吸收。     

鸡骨草微量元素含量的测定

用电感耦合等离子体发射光谱仪测定了湛江人工栽培的鸡骨草中微量元素含量,发现其钙、镁、铁、锌等元素的含量都较丰富,并讨论了这些有益元素与人体健康的关系。