54 resultados para Ariosto, Lodovico, 1474-1533.
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Hydrotalcite-like compounds containing carbonate ion as the interlayer anion were prepared by coprecipitation under low supersaturation condition by mixing an aqueous solution of metal nitrates with an aqueous solutions of NaOH and Na2CO3, at room temperature, maintaining pH = 8-10 with vigorous stirring, Following the mixing, the resulting heavy slurry was aged at 353 K for 18 h with vigorous stirring, The precipitate was then filtered, washed several times with hot distilled water and dried in air at 353 K overnight, In this way, CuMI AlCO3-HTLcs and M-I AlCO3-HTLcs were synthesized and characterized by means of XRD and IR, The catalysis of the above mentioned HTLcs were investigated in the phenol hydroxylation with H2O2. The results indicated that all of the copper-containing HTLcs had a higher catalytic activity in the reaction, However, those catalysts that did not contain copper had no catalytic activity in this reaction, This means that copper was the active center in the phenol hydroxylation. Meanwhile, the mechanism was also proposed, which could be used to explain the main reason for higher activity for CuCuAlCO3-HTLcs in the phenol hydroxylation and the effect of Mg2+, Zn2+, Co2+, Ni2+ on activity of CuMI AlCO3-HTLcs.
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合成了一系列二元、三元过渡金属水滑石类化合物,并经XRD、IR进行了表征.苯酚过氧化氢羟化结果表明,含铜水滑石类化合物对该反应有较高的催化活性,并初步提出了反应机理.
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HexafluorobisA polyethersulfone-cardo polyethersulfone, random and block copolymers with different segment lengths were synthesized by a reaction of 4,4'-(hexafluoroisopropylidene)diphenol and 3,3'-bis(4-hydroxyphenyl)-1-isobenzopyrrolidone with bis(4-chl
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Identification of protein interaction interfaces is very important for understanding the molecular mechanisms underlying biological phenomena. Here, we present a novel method for predicting protein interaction interfaces from sequences by using PAM matrix (PIFPAM). Sequence alignments for interacting proteins were constructed and parsed into segments using sliding windows. By calculating distance matrix for each segment, the correlation coefficients between segments were estimated. The interaction interfaces were predicted by extracting highly correlated segment pairs from the correlation map. The predictions achieved an accuracy 0.41-0.71 for eight intraprotein interaction examples, and 0.07-0.60 for four interprotein interaction examples. Compared with three previously published methods, PIFPAM predicted more contacting site pairs for 11 out of the 12 example proteins, and predicted at least 34% more contacting site pairs for eight proteins of them. The factors affecting the predictions were also analyzed. Since PIFPAM uses only the alignments of the two interacting proteins as input, it is especially useful when no three-dimensional protein structure data are available.
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长江口邻近海域夏季底层水体存在世界上面积最大的缺氧带。这为研究河口区氧化还原敏感元素的生物地球化学过程提供了天然的实验场所。为了理解长江河口缺氧带存在的生物地球化学过程,本文以长江口邻近海域缺氧带上覆水体、沉积物及间隙水为研究对象,并对其营养盐及重金属进行研究,目的在于揭示长江口邻近海域缺氧带可能存在的生物地球化学过程,为理解长江河口区的物质循环提供科学证据。通过研究得出如下结论:(1)在水体中盐度是影响营养盐分布的主要因素,在高浊度带存在营养盐释放的现象;(2)底层水存在两种显著不同的生物地球化学过程:当盐度<33 PSU时,营养盐与AOU之间为负相关,影响底层海水营养盐分布的主要因素可能为流场;而当盐度>33 PSU时,营养盐与AOU之间存在正相关,影响营养盐分布的主要因素为颗粒有机质的矿化;(3)溶解态痕量金属存在保守型(Mo、U、Ni)和混合型(Fe、Mn、Cu、Pb、Zn)的分布规律,盐度、浮游生物及溶解氧都是影响溶解态痕量金属分布的重要因素;剔除浊度大于20 NTU的数据,分配系数与浊度为显著正相关;(4)间隙水Fe、Mn剖面表明,长江河口表层沉积物存在剧烈的Fe、Mn还原现象;成岩模型模拟结果显示间隙水Mn的模拟剖面与实际观测剖面吻合较好。间隙水U剖面显示,控制U分布的主要因素与Fe有关,但是其它因素如有机质含量对U、Mo的分布也有影响;(5)间隙水营养盐剖面显示近岸与远岸存在两种不同的生物地球化学过程:远岸海域,间隙水营养盐部面主要受早期成岩的控制;而在近岸海域其它过程如氨化及吸附可能是控制间隙水氮剖面分布的主要因素;模拟剖面与NH4+的实测剖面趋于一致,但是同时暗示表层沉积物受到生物扰动;通量计算结果显示,Si、N、P分别占浮游生物每日所需要营养盐数量的15%、10%及0.1%;(6)对痕量金属的黄铁矿化程度进行了分析,发现长江河口痕量金属的黄铁矿化程度异常低,黄铁矿不是影响痕量金属分布的主要因素;导致低黄铁矿化度的原因与长江河口高沉积速率、贫硫、低有机质有关。
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本发明涉及一种从龙胆属药用植物中提取裂环烯醚萜甙(苦苷)类产物的工艺,其以龙胆属药用植物全草或根、茎、叶、花为原料,以亲水性溶剂回流提取,并利用对水溶性成分具有选择性吸附作用的大孔树脂进行分离和富集,得到裂环烯醚萜甙类产物,其中裂环烯醚萜甙类化合物的含量大于20%。本发明工艺简便、操作方便、安全、重复性好,可工业化生产。
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CIMS是将企业主要生产经营活动实现自动化的高度复杂的大规模集成系统;在CIMS的实践过程中,不仅要实现物流和信息流的集成,还要实现组织和功能的集成,进行系统运行过程的有效管理,才能从总体上实现生产的最优调度和控制,从而实现系统最优目标.本文从沈阳鼓风机厂CIMS工程的实际出发,讨论在信息集成的基础上,根据企业内部运行规律对SB-CIMS内的各功能模块进行协调管理,使CIMS内部各功能模块和谐地运行,从而实现功能的集成和系统的最优目标。
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In the practical seismic profile multiple reflections tend to impede the task of even the experienced interpreter in deducing information from the reflection data. Surface multiples are usually much stronger, more broadband, and more of a problem than internal multiples because the reflection coefficient at the water surface is much larger than the reflection coefficients found in the subsurface. For this reason most attempts to remove multiples from marine data focus on surface multiples, as will I. A surface-related multiple attenuation method can be formulated as an iterative procedure. In this essay a fully data-driven approach which is called MPI —multiple prediction through inversion (Wang, 2003) is applied to a real marine seismic data example. This is a pretty promising scheme for predicting a relative accurate multiple model by updating the multiple model iteratively, as we usually do in a linearized inverse problem. The prominent characteristic of MPI method lie in that it eliminate the need for an explicit surface operator which means it can model the multiple wavefield without any knowledge of surface and subsurface structures even a source signature. Another key feature of this scheme is that it can predict multiples not only in time but also in phase and in amplitude domain. According to the real data experiments it is shown that this scheme for multiple prediction can be made very efficient if a good initial estimate of the multiple-free data set can be provided in the first iteration. In the other core step which is multiple subtraction we use an expanded multi-channel matching filter to fulfil this aim. Compared to a normal multichannel matching filter where an original seismic trace is matched by a group of multiple-model traces, in EMCM filter a seismic trace is matched by not only a group of the ordinary multiple-model traces but also their adjoints generated mathematically. The adjoints of a multiple-model trace include its first derivative, its Hilbert transform and the derivative of the Hilbert transform. The third chapter of the thesis is the application for the real data using the previous methods we put forward from which we can obviously find the effectivity and prospect of the value in use. For this specific case I have done three group experiments to test the effectiveness of MPI method, compare different subtraction results with fixed filter length but different window length, invest the influence of the initial subtraction result for MPI method. In terms of the real data application, we do fine that the initial demultiple estimate take on a great deal of influence for the MPI method. Then two approaches are introduced to refine the intial demultiple estimate which are first arrival and masking filter respectively. In the last part some conclusions are drawn in terms of the previous results I have got.
Resumo:
利用三维荧光光谱研究了太阳辐射对溶解有机质(DOM)荧光光谱特征的影响。实验结果表明,太阳辐射使DOM的荧光发射光谱强度减弱。在三维荧光光谱图中,红枫湖样品的荧光峰A,C,南明河样品的荧光峰A,B,C,尤其是荧光峰C的λExmax/λEmmax位置随着太阳辐射时间的延长而逐渐向短波长移动。从腐殖酸样品的三维荧光光谱图中则发现,原始样品荧光峰位置出现在λEx/λEm=275/500nm处,光照作用后出现两个荧光峰λEx/λEm=245/450nm和310/450nm。太阳辐射对DOM中不同荧光组分的光降解速率存在差异,从荧光峰A和C的比值r(A,C)随太阳辐射时间的变化趋势得知,荧光峰C比荧光