1000 resultados para flatrening strategy
Resumo:
The present work describes a convenient approach to fabricate networked nonspherical gold nanostructures by using [G-2]-CO2H dendrimer and toluene as capping and bridging agents in a CH2Cl2 and H2O biphasic system. A controlled linear assembly is achieved without the use of any catalyst at room temperature. UV-vis spectrum, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) analysis show that the product is well networked nanostructures with diameter of 4-10 nm and consists of coalesced face-centered cubic gold nanocrystals. Extended experiments reveal that both benzene and dimethylbenzene can also inhabit the gold ions to make them crosslinked, prolong the nucleation points and eventually facilitate the formation of the networks.
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We construct a hybrid bilayer membrane (HBM) on a new substrate-carbon electrode. It is an extension of HBM based on other substrates. Primary alkylamine was chemically modified onto the surface of a carbon electrode by electrochemical scans; thus, a monolayer was formed on the electrode. Because the alkane chains section is toward the outside, a hydrophobic surface was constructed. Then a lipid monolayer was spread on the hydrophobic surface of the carbon electrode. The formed HBM was characterized by electrochemical and ATR-FT-IR methods. From ATR-FT-IR results, the lipid order parameter (S) of 0.73 was obtained. This kind of hybrid membrane has the advantages of a lipid/alkanethiol HBM. A potential application of this HBM as a biosensor (detecting K+) was given.
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Dendrimer-protected gold nanoparticles have been facilely obtained by heating an aqueous solution containing third generation poly(propyleneimine) dendrimers and HAuCl4 without the additional step of introducing other reducing agents. Transmission electron microscopy (TEM) and UV vis data indicate the size the nucleation and growth kinetics of gold nanoparticles thus formed which can be tuned by changing the initial molar ratio of dendrimer to gold.
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A relative approach, based on the dynamic density functional theory, for simulating the solvent evaporation rate dependence of self-assembly process of block copolymers in solution is proposed. The di- and triblock copolymers are first chosen as the candidates for exploration of novel microstructures. The results reveal that asymmetrical block copolymers with unequal block length, which generally exhibit disordered microdomain patterns in melts, have the ability to assemble into periodic ordered microdomain patterns by properly controlling solvent evaporation rate, e.g., diblock copolymers may assemble into lamellar microstructures with lamellar thickness proportional to individual block length. This simulation suggests a strategy of design and manufacture of polymeric nanomaterials with novel microstructures.
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The thickness of the gold film and its morphology, including the surface roughness, are very important for getting a good, reproducible response in the SPR technique. Here, we report a novel alternative approach for preparing SPR-active substrates that is completely solution-based. Our strategy is based on self-assembly of the gold colloid monolayer on a (3-aminopropyl)trimethoxysilane-modified glass slide, followed by electroless gold plating. Using this method, the thickness of films can be easily controlled at the nanometer scale by setting the plating time in the same conditions. Surface roughness and morphology of gold films can be modified by both tuning the size of gold nanoparticles and agitation during the plating. Surface evolution of the Au film was followed in real time by UV-vis spectroscopy and in situ SPRS. To assess the surface roughness and electrochemical stability of the Au films, atomic force microscopy and cyclic voltammetry were used. In addition, the stability of the gold adhesion is demonstrated by three methods. The as-prepared Au films on substrates are reproducible and stable, which allows them to be used as electrodes for electrochemical experiments and as platforms for studying SAMs.
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A rapid and convenient solid-supported iterative divergent/converpent approach was developed to prepare rigid phenylacetylene dendrimers. The generation number grows very rapidly and the purification at each step is very simple. (C) 2001 Elsevier Science Ltd. All rights reserved.
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This study investigated the delivery of a SV40 promoter driving lacZ gene into cells of Kappaphycus alvarezii using particle bombardment. Thallus pieces 0.5-0.8 mm in diameter and 1 cm in length were prepared as gene recipients. Bombardment parameters of 450 psi (rupture pressures) x 6 cm (particle travel distances), 650 psi x 6 cm, 1,100 psi x 6 cm and 1,100 psi x 9 cm were used. A significant increase in transformation efficiency from about 33% under the rupture pressure of 450 psi to 87% at 650 psi was observed in transformed thalli. Most of the positive cells appeared in epidermal cells bombarded at 450 psi, whereas positive signals were seen in both epidermal and medullary cells at 650 psi. No positive transient expression was detected at a bombardment of 1,100 psi, or in negative or blank controls. For the conditions tested, the best parameter was obtained at 650 psi at a distance of 6 cm. Thus, the strategy of taking vegetative thalli as recipients, using particle bombardment, and combining this with micro-propagation, together with developing an in vivo selectable marker, is a viable way to produce stable transformants, to eliminate chimeric expression, and to achieve transgenic breeding in K. alvarezii.
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With a "two-way pseudo-testcross" mapping strategy, we applied the amplified fragment length polymorphism (AFLP) markers to construct two moderate density genetic linkage maps for Laminaria. The linkage maps were generated from the 60 progenies of the F, cross family (Laminaria longissima Aresch. x L. japonica Miyabe) with twenty pairs of primer combinations. Of the 333 polymorphic loci scored in 60 progenies, 173 segregated in a 1:1 ratio, corresponding to DNA polymorphisms heterozygous in a single parent, and the other 58 loci existing in both parents followed a 3:1 Mendelian segregation ratio. Among the loci with 1:1 segregating ratios, 79 loci were ordered in 14 linkage groups (648.6 cM) of the paternal map, and 72 loci were ordered in 14 linkage groups (601.9 cM) of the maternal map. The average density of loci was approximately 1 per 8 cM. To investigate the homologies between two parental maps, we used 58 loci segregated 3:1 for further analysis, and deduced one homologous linkage group. The linkage data developed in these maps will be useful for detecting loci-controlling commercially important traits for Laminaria.
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We describe a psychophysical investigation of the effects of object complexity and familiarity on the variation of recognition time and recognition accuracy over different views of novel 3D objects. Our findings indicate that with practice the response times for different views become more uniform and the initially orderly dependency of the response time on the distance to a "good" view disappears. One possible interpretation of our results is in terms of a tradeoff between memory needed for storing specific-view representations of objects and time spent in recognizing the objects.
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Strategic management is constantly evolving as both an academic discipline and as a reflection of management practice. This article, based on a recent interview with Michael Porter, assesses his contribution to the development of the discipline in the context of the advances that have taken place since the publication of his seminal work Competitive Strategy in 1980. The authors conclude that Porter has made major lasting contributions to strategy, increasing both its academic rigor and its accessibility to managers. The article and interview place Porter's work at the center of the development of strategic management in terms of the provision of practical analytical frameworks, transforming it into a recognized and recognizable field of academic study and management practice. This feat of transformation has not been equaled before or since, so that 25 years after his first seminal contribution, Porter's work continues to provide remarkable insights into the nature of competition and strategy.
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This thesis sets out a journey which culminates in the development of an analytical framework, the "Organisational Creativity Appraisal" which is intended to assist organisations in evaluating their ability to support and develop creativity. This framework is derived from the common thread of the thesis, which is drawn from a range of research and consultancy projects, and the resulting published work, spanning an eight year period, centring on the role of knowledge and creativity in the strategy and performance of organisations. The literature of strategy, learning and creativity increasingly recognises that organisational context is critical to the formation of strategy, to the content of the strategy and to its successful implementation. The thesis explores the ways in which learning and creativity, the basis of knowledge-based strategy, are influenced by organisational context or social architecture. The research explores the ways in which managers can gain greater understanding of the social architectures of their organisations so as to assist in supporting their strategic development. The central core of the thesis is the nine published papers upon which it is based but it also derives from the broader perspective of my published work in the form of both articles and books. The thesis further draws upon my own experience as a leader and manager in the context of university business schools and as a consultant, researcher and developer in the context of a range of international private and public sector organisations. The work is based upon a premise that theory should inform practice and that practice should inform theory. The "Organisational Creativity Appraisal" framework is informed by both theory and practice and is intended to assist in management practice. There is no assumption that management research can arrive at prescriptions for managerial and organisational behaviour. On the other hand management research can usefully inform management and organisational behaviour, as long as it is employed in a critically reflective manner. The "Organisational Creativity Appraisal" presented in this work should be regarded as the framework in its present form which is likely to develop further as my research progresses in the future.
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Purpose – The purpose of this paper is to explore the relevance of human resource development (HRD) for law firms in the UK. It examines how the characteristics of legal professional practice in the UK, including the partnership structure, long established methods of targeting solicitors and the law society, may act as barriers to the implementation of HRD. Design/methodology/approach – The paper uses an exploratory case study research approach to investigate characteristics and issues influencing the adoption of HRD in a Scottish legal firm. Primary data are collected via semi-structured interviews with a cross-section of representatives. Findings – Despite recognition of the importance of learning, the characteristic elements of law firms, including the partnership structure; the pervasiveness of time-billed targets in the solicitor community; and HR’s profile and acceptance among the solicitor community, remain as barriers to the applicability of HRD. The research also exposes variability on the level and scope of development opportunities, an emphasis on technical skills development, and a lack of solicitors’ self-managed learning ability. Research limitations/implications – While the research findings provide a useful insight into the barriers to HRD in one legal firm, this does not allow for any generalisations being drawn from the study. Practical implications – The paper explores the suitability of workplace learning to support legal professional development. Originality/value – There is a dearth of research into HRD in legal practices in the UK. The paper contributes to the contextual influences that limit the applicability of HRD to legal professional practices.
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Developing learning, teaching and assessment strategies that foster ongoing engagement and provide inspiration to academic staff is a particular challenge. This paper demonstrates how an institutional learning, teaching and assessment strategy was developed and a ‘dynamic’ strategy created in order to achieve the ongoing enhancement of the quality of the student learning experience. The authors use the discussion of the evolution, development and launch of the Strategy and underpinning Resource Bank to reflect on the hopes and intentions behind the approach; firstly the paper will discuss the collaborative and iterative approach taken to the development of an institutional learning, teaching and assessment strategy; and secondly, the development of open access educational resources to underpin the strategy. The paper then outlines staff engagement with the resource bank and positive outcomes which have been identified to date, identifies the next steps in achieving the ambition behind the strategy and outlines the action research and fuller evaluation which will be used to monitor progress and ensure responsive learning at institutional level.
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This paper reprots on the use of banchmarking to improve the links between business and operations strategies. The use of benchmarking as a toll to facilitate improvements in these crucial links is examined. The existing literature on process benchmarking is used to from a structured questionnaire to apply to six case studies of major manuifacturing companies. Four of these case studies are presented in this paper to highlight the use of benchmarking in this application. Initial researh results are presented drawing upon the critical success factors indentified both in the literature and on the case results. Recommendations for further work are outlined