56 resultados para Giorgione, 1477-1511.
Resumo:
报道了顺-二氯二联吡啶钌(Ⅱ)和顺-二氯二邻二氮菲钉(Ⅱ)的核磁共振氢谱。利用1H-1H COSY谱详细分析并归属了这两种络合物的氢谱峰,并给出了各质子的偶合数,同时验证了其顺式的立体构型。
Resumo:
Gas phase ion-molecular reactions of endohedral metallofullerenes with the self-chemical ionization ion system of vinyl acetate, benzene and acetone in the ion source of the mass spectrometer have been studied. Several derivatized endohedral metallofullerene cations [M@C-82-C2H3O](+), [M-2@C-80-C2H3O](+), [M@C-82-C6H6](+) and [M@C-82-CO-CH3](+) are observed as the major products. The experimental results indicate that endohedral metallofullerenes have active gas phase reactivities and can be efficiently derivatized by some small organic cations.
Resumo:
A new solid solution series, NdSr(1-x)M(x)NiO(4) (M = Ca: 0.0 less than or equal to x less than or equal to 1.0; M = Ba: 0.0 less than or equal to x less than or equal to 0.6), was synthesized by solid state reaction, and the structures, magnetic and electrical properties and optical spectra of this series have been studied. All the samples crystalized in tetragonal systems, with the exception of NdCaNiO4, which crystallized in the orthohombic system. IR spectra of NdSr1-xCaxNiO4 indicated that the lengths of two Ni-O bonds decrease with increasing Ca content. The electrical conduction changed from metallic-type to semiconductive-type when x greater than or equal to 0.4 (M = Ca, Ba), and the room temperature resistivities of NdSr1-xCaxNiO4 increased with the increase of Ca content. Magnetic susceptibility measurements revealed that Ni+3 ions in all the samplies were in low-spin state over the temperature range 77-300 K.
Resumo:
本发明涉及扁蕾植物的引种栽培技术,该技术包括种子处理和引种栽培工艺。本发明通过对扁蕾植物种子进行物理和化学处理,使扁蕾种子萌发率达70%以上;通过地膜覆盖技术,即在种子播种前采用地膜覆盖7-28天,可有效地控制杂草数量和生长,为规模化种植奠定可靠的基础;通过在海拔 1500-4500米的原产水浇大田或适宜旱耕地的引种栽培途径,可快速恢复扁蕾的资源量,并有效地保证扁蕾的药材品质和药效成分。
Resumo:
本文在[1]扩展关系模型中引入属性级的不完全信息空值。为适应此环境下更新操作的需要,本文对[1]中的扩展关系模型进行了进一步的扩展,并以此模型为基础讨论了空值环境下含不确定及可能信息关系数据库的更新操作的策略,给出了相应的处理算法。
Resumo:
本文详细介绍了我们为“探索者”号自治式无缆水下机器人(以下简称AUV)设计的控制软件体系结构。该体系结构可分为使命控制,运动监控与设备操作,实时调度和实时处理四个不同的控制层次及一个全局数据区五部分。
Resumo:
在过去很长一段时间里重金属含量的高低一直都被看作是土壤污染程度的一个重要指标.当化学相的概念被引入到环境科学领域后,人们才逐渐地认识到重金属在环境中的行为和作用,如活动性、生物可利用性、毒性等,用这些金属在环境中的总量来预测和解释是不确切的。为此,许多化学和生物的方法被用来描述土壤与沉积物中重金属的活性。文章对近年来在该领域内的主要研究工作进行了总结,并对其未来可能的发展方向提出了自己的见解。
Resumo:
选择和使用合适的示踪指标,是揭示岩溶地区红色风化壳物质来源的关键。粒度参数在古环境研究中被大家广泛采用,但是在风化壳物源示踪方面还是新的尝试,尤其在我国。本文选择贵州中部平坝县3个下伏基岩为白云岩的缺失原岩结构的红色风化壳剖面,通过基岩酸不溶物和剖面的粒度分析,表明红色风化壳物质对下伏基岩有很好的继承性。粒度参数随剖面深度呈规律变化,指示了标准残积风化壳的发育特征。