983 resultados para Amalteo, Pomponio, 1505-1588.
Resumo:
Copolymerizations of ethylene with 5-vinyl-2-norbornene or 5-ethylidene-2-norbornene under the action of various titanium complexes bearing bis(beta-enaminoketonato) chelate ligands of the type, [(RN)-N-1=C(R-2)CH=C(R-3)O](2)TiCl2 (1, R-1=Ph, R-2=CF3, R-3=Ph; 2, R-1=C6H4F-p, R-2=CF3, R-3=Ph; 3, R-1=Ph, R-2=CF3, R-3=t-Bu; 4, R-1=C6H4F-p, R-2=CF3, R-3=t-Bu; 5, R-1=Ph, R-2=CH3, R-3=CF3; 6, R-1=C6H4F-p, R-2=CH3 R-3=CF3), have been shown to occur with the regioselective insertion of the endocyclic double bond of the monomer into the copolymer chain, leaving the exocyclic vinyl double bond as a pendant unsaturation. The ligand modification strongly affects the copolymerization behaviour. High catalytic activities and efficient co-monomer incorporation can be easily obtained by optimizing the catalyst structures and polymerization conditions.
Resumo:
The phase stability of lanthanum cerium oxide (La2Ce2O7), which is stable up to 1400 degrees C, and the thermal expansion coefficient of La2Ce2O7 doped with Ta2O5 or WO3 were studied. The thermal expansion coefficient of La2Ce2O7 below 400 degrees C was increased by adding more CeO2 or doping with either Ta2O5 or WO3.
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:
设计了一种简易实用的长光程薄层光谱电化学池,该池以10mm石英比色槽为光学窗,2块5×10×50mm的聚四氟乙烯块为电极支承体,玻碳片为工作电极,且薄层厚度可调。以K_3Fe(CN)_6和L-酪氨酸为工作体系进行光谱和电化学实验表明,该池具有良好的薄层电化学特征。对于水溶液,在大于220nm波长内给出良好的光谱和较快的光谱电化学响应,可方便地用于圆二色谱-电化学研究。
Resumo:
Artemia has evolved a unique developmental pattern of encysted embryos to cope with various environmental threats. Cell divisions totally cease during the preemergence developmental stage from gastrula to prenauplius. The molecular mechanism of this, however, remains unknown. Our study focuses on the involvement of p90 ribosomal S6 kinase (RSK), a family of serine/threonine kinase-mediating signal transduction downstream of mitogen-activated protein kinase cascades, in the termination of cell cycle arrest during the post-embryonic development of Artemia-encysted gastrula. With immunochemistry, morphology, and cell cycle analysis, the identified Artemia RSK was established to be specifically activated during the post-embryonic and early larval developmental stages when arrested cells of encysted embryos resumed mitoses. In vivo knockdown of RSK activity by RNA interference, kinase inhibition, and antibody neutralization consistently induced defective larvae with distinct gaps between the exoskeleton and internal tissues. In these abnormal individuals, mitoses were detected to be largely inhibited in the affected regions. These results display the requirement of RSK activity during Artemia development and suggest its role in termination of cell cycle (G(2)/M phase) arrest and promotion of mitogenesis. Our findings may, thus, provide insights into the regulation of cell division during Artemia post-embryonic development and reveal further aspects of RSK functions.
Resumo:
Authigenic carbonates were sampled in methane-enriched piston core sediments collected from gas venting sites on the western continental slope of the Ulleung Basin, East Sea of Korea. Multidisciplinary investigations on these carbonates, including the scanning electronic microscope (SEM) observations and mineralogical-geochemical compositions, were carried out to identify the carbon and oxygen sources and the forming mechanism of these carbonates. The authigenic carbonates from the study area correspond to semi-consolidated, compact concretions or nodules ranging from 2 to 9 cm in size. X-ray diffraction and electron microprobe analyses showed that most of the sampled carbonate concretions were composed of almost purely authigenic high-Mg calcite (10.7-14.3 mol% MgCO3). Characteristically, microbial structures such as filaments and rods, which were probably associated with the authigenic minerals, were abundantly observed within the carbonate matrix. The carbonates were strongly depleted in delta C-13 (-33.85 parts per thousand to -39.53 parts per thousand Peedee Belemnite (PDB)) and were enriched in delta O-18 (5.16-5.60 parts per thousand PDB), indicating that the primary source of carbon is mainly derived from the anaerobic oxidation of methane. Such methane probably originated from the destabilization of the underlying gas hydrates as strongly supporting from the enriched O-18 levels. Furthermore, the strongly depleted delta C-13 values (-60.7 parts per thousand to -61.6 parts per thousand PDB) of the sediment void gases demonstrate that the majority of the gas venting at the Ulleung Basin is microbial methane by CO2 reduction. This study provides another example for the formation mechanism of methane-derived authigenic carbonates associated with gas-hydrate decomposition in gas-seeping pockmark environments. (c) 2009 Elsevier Ltd. All rights reserved.
Resumo:
工业自动化总体技术是在CIM思想指导下产生的实施CIM的关键技术。总体技术的核心是总体设计与总体集成技术。本文言及总体技术产生的背景,其宗旨与含义,总体技术方法学,工业自动化系统体系结构与参考模型,以及实践总体技术的概况动向。
Resumo:
Integrating geology, core, well-logging, experimental data, and production data, with the guide of sequence stratigraphy, sedimentology, reservoir exploitation geology and other disciplines’ theories, combinating the sequence stratigraphy and Maill’s reservoir architectures concepts and theories, the research and analysis methods of non-marine fan-delta reservoir architectures are systemly set out. And the correspondence of reservoir structures, sedimentology and reservoir geology is established. An integral and systematical research approach and theory and conception of reservoir architecture is developed, which enriched the reservoir research theory. Considering the requirement to the reservoir research in different development phase, the six classification systems of reservoir architectures are brought up. According to different reservoir’s connection and location of Ek different levels of reservoir architecture, 3 types, 20 kind architectures styles are summarized. The research about undisturbed reservoir characterization is launched, through analyzing reservoir characterization to pour water to the different reservoirs of Kongnan region, the changing regular pattern of reservoir quality during pouring water process is summarized. Combined with the actual zone data, inner-well reservoir geometry relationship of injection-production model is designed, and the models of development process are dynamic simulated. In view of seven laboratory samples of 3 types, six order architecture unit of braided stream, fan-delta and nearshore subsea apron in Kongnan region, the remaining oil distribution model is determined. Using the geo-statistics methods dissect the key regions, the tectono-stratigraphical model and the reservoir parameters model are established. The distribution of the characteristics of the underground reservoir is quantitatively described. Based on the reservoir research, carrying out the development of different characteristics of reservoir, the development pattern and countermeasures are determined. The relationships between reservoir structure levels and reservoir development stages are summed up, the relationships between architecture unit of different levels and exploration develop stages are determined.
Resumo:
碳酸盐岩由于酸不溶物含量极低,在形成风化壳的过程中伴随巨大的体积缩小,形成1m厚的风化壳往往需要消耗原岩十几米至几十米。所以对于岩溶地区风化壳,尤其是厚层红色风化壳的机理研究中,母岩的均一性判别是必要的,是风化壳研究的基础。通过对贵州岩溶地区贵阳花溪、湖潮剖面和黔北遵义市新蒲剖面三个典型的残积风化壳的粒度分析表明,碳酸盐岩风化壳成土母岩的不均一性是客观存在的,从粒度分布特征给予了良好的指示。而不均一母岩上发育的风化壳的地球化学行为,也必然偏离建立在均一母岩前提下的风化壳的正常演化方向。此外,常作为表生环境下物源示踪的惰性元素比
Resumo:
Poolton, Nigel; Hamilton, B.; Evans, D.A., (2005) 'Synchrotron-laser pump-probe luminescence spectroscopy: Correlation of electronic defect states with x-ray absorption in wide-gap solids', Journal of Physics D: Applied Physics 38 pp.1478-1484 RAE2008
Resumo:
University of California Libraries
Resumo:
A method is proposed that can generate a ranked list of plausible three-dimensional hand configurations that best match an input image. Hand pose estimation is formulated as an image database indexing problem, where the closest matches for an input hand image are retrieved from a large database of synthetic hand images. In contrast to previous approaches, the system can function in the presence of clutter, thanks to two novel clutter-tolerant indexing methods. First, a computationally efficient approximation of the image-to-model chamfer distance is obtained by embedding binary edge images into a high-dimensional Euclide an space. Second, a general-purpose, probabilistic line matching method identifies those line segment correspondences between model and input images that are the least likely to have occurred by chance. The performance of this clutter-tolerant approach is demonstrated in quantitative experiments with hundreds of real hand images.
Resumo:
Communication and synchronization stand as the dual bottlenecks in the performance of parallel systems, and especially those that attempt to alleviate the programming burden by incurring overhead in these two domains. We formulate the notions of communicable memory and lazy barriers to help achieve efficient communication and synchronization. These concepts are developed in the context of BSPk, a toolkit library for programming networks of workstations|and other distributed memory architectures in general|based on the Bulk Synchronous Parallel (BSP) model. BSPk emphasizes efficiency in communication by minimizing local memory-to-memory copying, and in barrier synchronization by not forcing a process to wait unless it needs remote data. Both the message passing (MP) and distributed shared memory (DSM) programming styles are supported in BSPk. MP helps processes efficiently exchange short-lived unnamed data values, when the identity of either the sender or receiver is known to the other party. By contrast, DSM supports communication between processes that may be mutually anonymous, so long as they can agree on variable names in which to store shared temporary or long-lived data.
Resumo:
This thesis is focused on the synthesis and solid state analysis of carbohydrate derivatives, including many novel compounds. Although the synthetic chemistry surrounding carbohydrates is well established in the literature, the crystal chemistry of carbohydrates is less well studied. Therefore this research aims to improve understanding of the solid state properties of carbohydrate derivatives through gaining more information on their supramolecular bonding. Chapter One focuses on an introduction to the solid state of organic compounds, with a background to crystallisation, including issues that can arise during crystal growth. Chapter Two is based on glucopyranuronate derivatives which are understudied in terms of their solid state forms. This chapter reports on the formation of novel glucuronamides and utilising the functionality of the amide bond for crystallisation. TEMPO oxidation was completed to form glucopyranuronates by oxidation of the primary alcohol groups of glucosides to the carboxylic acid derivatives, to increase functionality for enhanced crystal growth. Chapter Three reports on the synthesis of glucopyranoside derivatives by O-glycosylation reactions and displays crystal structures, including a number of previously unsolved acetate protected and deprotected crystal structures. More complex glycoside derivatives were also researched in an aim to study the resultant supramolecular motifs. Chapter Four contains the synthesis of aryl cellobioside derivatives including the novel crystal structures that were solved for the acetate protected and deprotected compounds. Research was carried out to determine if 1-deoxycellodextrins could act as putative isostructures for cellulose. Our research displays the presence of isostructural references with 1-deoxycellotriose shown to be similar to cellulose III11, 1-deoxycellotetraose correlates with cellulose IV11 and 1-deoxycellopentose shows isostructurality similar to that of cellulose II. Chapter Five contains the full experimental details and spectral characterisation of all novel compounds synthesised in this project and relevant crystallographic information.