509 resultados para EPITAXIAL-GROWTH


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It is known that boehmite (AlOOH) nanofibers formed in the presence of nonionic poly(ethylene oxide) (PEO) surfactant at 373 K. A novel approach is proposed in this study for the growth of the boehmite nanofibers: when fresh aluminum hydrate precipitate was added at regular interval to initial mixture of boehmite and PEO surfactant at 373 K, the nanofibers grow from 40 to 50 nm long to over 100 nm. It is believed that the surfactant micelles play an important role in the nanofiber growth: directing the assembly of aluminum hydrate particles through hydrogen bonding with the hydroxyls on the surface of aluminum hydrate particles. Meanwhile a gradual improvement in the crystallinity of the fibers during growth is observed and attributed to the Ostwald ripening process. This approach allows us to precisely control the size and morphology of boehmite nanofibers using soft chemical methods and could be useful for low temperature, aqueous syntheses of other oxide nanomaterials with tailorable structural specificity such as size, dimension and morphology.

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A month-long intensive measurement campaign was conducted in March/April 2007 at Agnes Water, a remote coastal site just south of the Great Barrier Reef on the east coast of Australia. Particle and ion size distributions were continuously measured during the campaign. Coastal nucleation events were observed in clean, marine air masses coming from the south-east on 65% of the days. The events usually began at ~10:00 local time and lasted for 1-4 hrs. They were characterised by the appearance of a nucleation mode with a peak diameter of ~10 nm. The freshly nucleated particles grew within 1-4 hrs up to sizes of 20-50 nm. The events occurred when solar intensity was high (~1000 W m-2) and RH was low (~60%). Interestingly, the events were not related to tide height. The volatile and hygroscopic properties of freshly nucleated particles (17-22.5 nm), simultaneously measured with a volatility-hygroscopicity-tandem differential mobility analyser (VH-TDMA), were used to infer chemical composition. The majority of the volume of these particles was attributed to internally mixed sulphate and organic components. After ruling out coagulation as a source of significant particle growth, we conclude that the condensation of sulphate and/or organic vapours was most likely responsible for driving particle growth during the nucleation events. We cannot make any direct conclusions regarding the chemical species that participated in the initial particle nucleation. However, we suggest that nucleation may have resulted from the photo-oxidation products of unknown sulphur or organic vapours emitted from the waters of Hervey Bay, or from the formation of DMS-derived sulphate clusters over the open ocean that were activated to observable particles by condensable vapours emitted from the nutrient rich waters around Fraser Island or Hervey Bay. Furthermore, a unique and particularly strong nucleation event was observed during northerly wind. The event began early one morning (08:00) and lasted almost the entire day resulting in the production of a large number of ~80 nm particles (average modal concentration during the event was 3200 cm-3). The Great Barrier Reef was the most likely source of precursor vapours responsible for this event.

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Major South-East Asian city-regions have experienced considerable physical, economic and social transformations during the past three decades. The rapid pace of globalisation and economic restructuring has resulted in these city-regions receiving the full impact of urbanisation pressures. In an attempt to ease these pressures, city-regions such as Bangkok, Seoul, Tokyo, Taipei, Hong Kong, Singapore and Kuala Lumpur have advocate growth management approaches giving particular interest to urban sustainability. These approaches promote efforts to achieve the triple bottom line sustainability by balancing economic and social development, and environmental protection, and putting more emphasis on compact and optimum development of urban forms. This paper evaluates the case of two South-East Asian city-regions, Kuala Lumpur and Hong Kong, and assesses their experiences in managing their urban forms whilst promoting sustainable patterns of urban development. The findings show that sustainable urban development initiatives employing a top down approach has yielded encouraging results in these case study city-regions. However the need for a more concerted effort towards the overall sustainability agenda still remains vital.

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Growth rods are commonly used for the treatment of scoliosis in the immature spine. Many variations have been proposed but breakage of implants is a common problem. Growth rod insertion commonly involves large exposures at initial insertion followed by multiple smaller procedures for lengthening. We present our early experiences using a percutaneous technique of insertion of a new titanium mobile bearing implant (Medtronic Inc). The implant allows some rotatory motion in the middle of the construct thus reducing construct stresses and thus possibly reducing rod breakage risk. Based on this small initial series with 12 months follow-up, percutaneous insertion of growth rods using the new implant is a safe and reliable technique although the infection rate in our sample was of note. This may be related to the titanium wear and inflammation seen in the soft tissues at time of operation and visualised on histology. No implants have required removal due to infection, and all infections were treated with debridement at next lengthening and suppressive antibiotics. Propionibacterium is one of the commonest infections seen with spinal implants and sometimes does not respond to simple antibiotic suppression. The technique allows preservation of the soft tissues until definitive fusion is needed and may lead to a decrease in hospital stay. The implant is low profile and seems to offer advantages over other systems on the market. Further follow up is needed to look at longer term outcomes with this new implant type.

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In studies of media industries, too much attention has been paid to providers and firms, too little to consumers and markets. But with user-created content, the question first posed more than a generation ago by the uses & gratifications method and taken up by semiotics and the active audience tradition (‘what do audiences do with media?’), has resurfaced with renewed force. What’s new is that where this question (of what the media industries and audiences did with each other) used to be individualist and functionalist, now, with the advent of social networks using Web 2.0 affordances, it can be re-posed at the level of systems and populations as well.

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I invented YouTube. Well, not YouTube exactly, but something close – something called YIRN; and not by myself exactly, but with a team. In 2003-5 I led a research project designed to link geographically dispersed young people, to allow them to post their own photos, videos and music, and to comment on the same from various points of view – peer to peer, author to public, or impresario to audience. We wanted to find a way to take the individual creative productivity that is associated with the Internet and combine it with the easy accessibility and openness to other people’s imagination that is associated with broadcasting; especially, in the context of young people, listening to the radio. So we called it the Youth Internet Radio Network, or YIRN.

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Sales growth and employment growth are the two most widely used growth indicators for new ventures; yet, sales growth and employment growth are not interchangeable measures of new venture growth. Rather, they are related, but somewhat independent constructs that respond differently to a variety of criteria. Most of the literature treats this as a methodological technicality. However, sales growth with or without accompanying employment growth has very different implications for managers and policy makers. A better understanding of what drives these different growth metrics has the potential to lead to better decision making. To improve that understanding we apply transaction cost economics reasoning to predict when sales growth will be or will not be accompanied by employment growth. Our results indicate that our predictions are borne out consistently in resource-constrained contexts but not in resource-munificent contexts.

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This Paper first provides a review and analysis of the recent trends on innovation infrastructures developed in industrialised countries to promote innovation and competitiveness for high growth SMEs. It specifically aims to examine various spatial models developed to support provision of innovation infrastructure for high growth sector.

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Entrepreneurial marketing has gained popularity in both the entrepreneurship and marketing disciplines in recent times. The success of ventures that have pursued what are considered non-traditional marketing approaches has been attributed to entrepreneurial marketing practices. Despite the multitude of marketing concepts and models, there are prominent venture successes that do not conform to these and have thus been put in the ''entrepreneurial'' box. One only has to look to the ''Virgin'' model to put this in context. Branson has proven for example that not ''sticking to the knitting'' can work with the ways the Virgin portfolio has been diversified. Consequently, an entrepreneurial orientation is considered a desirable philosophy and has become prominent in such industries as airlines and information technology. Miles and Arnold (1991) found that entrepreneurial orientation is positively correlated to marketing orientation. They propose that entrepreneurial orientation is a strategic response by firms to turbulence in the environment. While many marketing successes are analysed in hindsight using traditional marketing concepts and strategies, there are those that challenge standard marketing textbook recommendations. Marketing strategy is often viewed as a process of targeting, segmenting and positioning (STP). Academics and consultants advocate this approach along with the marketing and business plans. The reality however is that a number of businesses do not practice these and pursue alternative approaches. Other schools of thought and business models have been developing to explain differences in orientation such as branding (Keller 2001), the service-dominant logic (Vargo and Lusch 2004) and effectuation logic (Sarasvathy 2001). This indicates that scholars are now looking to cognate fields to explain a given phenomenon beyond their own disciplines. Bucking this trend is a growing number of researchers working at the interface between entrepreneurship and marketing. There is now an emerging body of work dedicated to this interface, hence the development of entrepreneurial marketing as an alternative to the traditional approaches. Hills and Hultman (2008:3) define entrepreneurial marketing as ''a spirit, an orientation as well as a process of passionately pursuing opportunities and launching and growing ventures that create perceived customer value through relationships by employing innovativeness, creativity, selling, market immersion, networking and flexibility.'' Although it started as a special interest group, entrepreneurial marketing is now gaining recognition in mainstream entrepreneurship and marketing literature. For example new marketing textbooks now incorporate an entrepreneurial marketing focus (Grewal and Levy 2008). The purpose of this paper is to explore what entrepreneurial approaches are used by entrepreneurs and their impact on the success of marketing activities. Methodology/Key Propositions In order to investigate this, we employ two cases: 42Below, vodka producers from New Zealand and Penderyn Distillery, whisky distillers from Wales. The cases were chosen based on the following criteria. Firstly, both companies originate from small economies. Secondly, both make products (spirits) from locations that are not traditionally regarded as producers of their flagship products and thirdly, the two companies are different from each other in terms of their age. Penderyn is an old company established in 1882, whereas 42Below was founded only in 1999. Vodka has never been associated with New Zealand. By the same token, whisky has always been associated with Scotland and Ireland but never been with Wales. Both companies defied traditional stereotypes in marketing their flagship products and found international success. Using a comparative a case study approach, we use Covin and Slevin's (1989) set of items that purport to measure entrepreneurial orientation and apply a qualitative lens on the approaches of both companies. These are: 1. cultural emphases on innovation and R&D 2. high rate of new product introduction 3. bold, innovative product development 4. initiator proactive posture 5. first to introduce new technologies and products 6. competitive posture toward competitor 7. strong prolictivity for high risk, high return projects 8. environment requires boldness to achieve objectives 9. when faced with risk, adopts aggressive, bold posture. Results and Implications We find that both companies have employed entrepreneurial marketing approaches but with different intensities. While acknowledging that they are different from the norm, the specifics of their individual approaches are dissimilar. Both companies have positioned their products at the premium end of their product categories and have emphasised quality and awards in their communication strategies. 42Below has carved an image of irreverence and being non-conformist. They have unashamedly utilised viral marketing and entered international markets by training bartenders and hosting unconventional events. They use edgy language such as vodka university, vodka professors and vodka ambassadors. Penderyn Distillery has taken a more traditional approach to marketing its products and portraying romantic images of age-old tradition of distilling as key to their positioning. Both companies enjoy success as evidenced by industry awards and international acclaim.