998 resultados para Avril, Mademoiselle (18..-18..) -- Portraits


Relevância:

40.00% 40.00%

Publicador:

Resumo:

2-丙烯酰胺基烷磺酸的溶解行为和胶体化学性质明显随烷基长短而异。由于手性碳原子的存在,与其相邻亚甲基的质子峰在~1HNMR谱上清楚地发生分裂。研究了2-丙烯酰胺基十六烷磺酸(AMC16S)在水/二氧六环混合溶剂中的聚合动力学和胶体化学性质。发现聚合速度和所得聚合物分子量均在水/二氧六环体积比为1~1/2时出现最小值,临界胶束浓度随混合溶剂中二氧六环含量的增加而增加,当水/二氧六环体积比为1/2~1/4时,观察不到胶束化现象。

Relevância:

40.00% 40.00%

Publicador:

Resumo:

合成了杂多化合物K8[P2W(18)Mo2Co2(H_2O)2O(68)]·MoO6·15H2O,依据XRD、IR、UV-Vis及XPS确定了其晶体结构和配位原子价态,考察了该化合物催化H2O2分解的动力学行为。

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Li~-和H~-因较强的亲水性,较难穿越液/液界面进行传输。本文报道了冠醚双环已基18冠6对Li~+,Na~+,Rb~-和H~-在水/硝基苯界面的促进传输行为,求得了相应促进传输过程的一系列参数,并对被传输离子在传输过程中的形态变化进行了初步的探讨。

Relevância:

40.00% 40.00%

Publicador:

Resumo:

本文研究了电子轰击、化学电离条件下四碘合钴酸十八胺、四氯合钴酸十八胺加热分解产生的C_(18)H_(37)NH_3~+(m/z270)离子碰撞诱导解离谱,在低碰撞能量范围(0~10eV)、多次碰撞条件下观察到了远电荷碎裂反应,给出了反应所需内能的估计值,该离子比直接由正十八胺质子化得到的离子具有较高的内能。

Relevância:

40.00% 40.00%

Publicador:

Resumo:

In this paper a carbon fibre (CF) microelectrode modified with the 2:18-molybdodiphosphate anion by simple adsorption is described and its electrochemical behaviour is reported. The 2:18-molybdodiphosphate anion (alpha-P2Mo18O626-), which is a Dawson structure, undergoes five successive multielectron reductions in acidic solution. The first three redox waves correspond to the two-electron process, and the last two waves are four-electron and six-electron processes respectively. On the basis of the experimental results it is shown that the electrode process of alpha-P2Mo18O626- on the CF electrode in acidic solution is simultaneously controlled by the diffusion and adsorption of alpha-P2Mo18O626- anions. When the concentration of the alpha-P2Mo18O626- in the solution is reduced, the electrode process mainly exhibits non-diffusion-controlled behaviour, and the diffusion-limited process takes over as the concentration of alpha-P2Mo18O626- becomes higher. The CF electrode modified with a thin film of alpha-P2Mo18O626- exhibits very good stability and redox behaviour in aqueous acidic solution. The alpha-P2Mo18O626- is reduced to heteropoly blue, with an accompanying protonation process. The addition of more than six electrons to the alpha-P2Mo18O626- anion in an aqueous solution does not result in its decomposition. The result obtained is not the same as that reported previously.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

A piston sediment core E017 from the middle-southern Okinawa Trough was investigated. A preliminary study of the deep-water evolution since 18 cal. ka BP was performed based on the quantitative census data of benthic foraminiferal fauna, together with planktonic foraminiferal oxygen and carbon isotope, AMS(14)C dating, and the previous results achieved in the southern Okinawa Trough. The result shows that the benthic fauna was dominated by Bulimina aculeata (d'Orbigny), Uvigerina peregrina (Cushman), Hispid Uvigerina and Uvigerina dirupta (Todd) during the glaciation-deglaciation before 9.2 cal. ka BP, while Epistominella exigua (Brady), Pullenia bulloides (d'Orbigny), Cibicidoides hyalina (Hofker), Sphaeroidina bulloides (d'Orbigny) and Globocassidulina subglobosa (Brady) predominated the fauna in the post-glacial period after 9.2 cal. ka BP. The benthic foraminifera accumulation rate (BFAR), paleoproductivity estimates and benthic foraminiferal assemblage conformably indicate that surface water paleoproductivity and organic matter flux during the glaciation-deglaciation were higher than those of the post-glacial period in the middle-southern Okinawa Trough, and gradually enhanced from the southern to the central Okinawa Trough during the glaciation-deglaciation, which could be caused by the discrepancy of the terrigenous nutrients supply. High abundances of E exigua, an indicator of pulsed organic matter input, after 9.2 cal. ka. BP may indicate that the intensity of seasonally riverine pulsed flux during the post-glacial period was stronger than that of the glaciation-deglaciation period, and the seasonal influx in the central trough might be stronger than in the south. The temporal distributions of the typical species indicating bottom water oxygen content and ventilation condition show that the ventilation of the bottom water during the post-glacial period is more active than the glaciation-deglaciation, which reflects that the evolution of the intermediate and deep waters of the northwestern Pacific during the last glaciation has no evident influence on the deep-water of the middle-southern Okinawa Trough. Additionally, the variations in agglutinated benthic foraminiferal abundance and other carbonate dissolution proxies indicate that carbonate dissolution gradually increased since the last 18 ka in the Okinawa Trough and rapidly enhanced at 9.2 cal. ka BP. The modern shallow carbonate lysocline could form at 3 cal. ka BP.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

目前,ROV(无人遥控潜水器)在水下工程和海洋石油工业上得到了广泛应用。ROV是通过各种水下作业工具来完成相应的作业任务。本文介绍了一种ROV携带海上石油钻井平台需要的新型水下作业工具一钢圈取放器。

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Critérios para determinar o ponto de colheita de bananas. Visual. Número de dias após o lançamento da inflorescência. Época de colheita da Fhia 18.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Este trabalho visa orientar os produtores e técnicos que têm interesse em formar novos rebanhos com fêmeas acasaladas aos 15 ou 18 meses de idade. Tais orientações, no entanto, só serão válidas quando outros aspectos de manejo forem também observados, tais como: controle sanitário eficiente, estação de monta bem definida, controle adequado da qualidade e quantidade de pastagem disponível, etc.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

One of the crucial stages of the Apostle Paul’s ministry was his stay at Ephesus. However, considering the fact that the reliability of some data in the Acts of the Apostles on the time of Paul’s arrival to Ephesus is nowadays frequently put into question, it has become necessary to investigate the issue. In the present article the author assesses the relevant source material and takes a stand on the particular opinions of contemporary interpreters of the subject. Based on an analysis of the text of the Acts of the Apostles he is led to conclude that Luke’s account of Paul’s first short visit to Ephesus reveals traits of historicity.