2,501 research outputs found

    Low-distortion slow light using two absorption resonances

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    We consider group delay and broadening using two strongly absorbing and widely spaced resonances. We derive relations which show that very large pulse bandwidths coupled with large group delays and small broadening can be achieved. Unlike single resonance systems, the dispersive broadening dominates the absorptive broadening which leads to a dramatic increase in the possible group delay. We show that the double resonance systems are excellent candidates for realizing all-optical delay lines. We report on an experiment which achieved up to 50 pulse delays with 40% broadening.Comment: 4 pages 4 figure

    Rapidly reconfigurable slow-light system based on off-resonant Raman absorption

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    We present a slow-light system based on dual Raman absorption resonances in warm rubidium vapor. Each Raman absorption resonance is produced by a control beam in an off-resonant Λ system. This system combines all optical control of the Raman absorption and the low-dispersion broadening properties of the double Lorentzian absorption slow light. The bandwidth, group delay, and central frequency of the slow-light system can all be tuned dynamically by changing the properties of the control beam. We demonstrate multiple pulse delays with low distortion and show that such a system has fast switching dynamics and thus fast reconfiguration rates

    Bibliometrically Mapping Team Cognition Literature: A Co-citation Analysis

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    Researchers investigating team cognition must source and review a challenging set of relevant, mature literature from a diverse array of academic disciplines. Such disciplines may include psychology, management, information science, military science, anthropology, and nursing science, etc. This thesis summarizes an effort to bibliometrically map team cognition literature using an author co-citation analysis methodology. The work began with a traditional literature review that identified key authors who were published in peer-reviewed journals. These authors were contacted and asked to provide their own listings of key researchers in the field, which were used in conjunction with the Social Sciences Citation Index (SSCI) to construct a co-citation matrix of authors. Using factor analysis and multi-dimensional analysis techniques, visual maps were constructed that highlight the influence of specific authors, the relationships between authors, and the branching of sub-domains in the literature over time. The overall goals of the research were to provide team cognition researchers with a tool they could use to better inform their efforts, and to provide an explicit mapping of the field in terms of where it has been, and where it may be going

    Microstructural influence on dynamic properties of age hardenable FeMnAl alloys

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    A lightweight castable alloy was sought to reduce the MIL-PRF-32269 class II cast steel perforated armor\u27s weight with the requirement that the material had to be manufactured utilizing existing foundry technology and without incurring large alloy cost increases to meet property requirements. Literature on wrought age hardenable Fe-Mn-Al-C alloys suggested this alloy system could achieve weight reduction through high aluminum concentrations with the highest reported strengths exceeding 2 GPa for a Fe-30Mn-9Al-0.9C composition. Even though ballistic testing had not been conducted on this system, high strain rate data of wrought alloys showed excellent work hardenability; greater than existing ballistic metals. Cast material property information was severely limited, thus, a systematic approach was employed to develop casting and processing techniques and assess related structure property relationships of a nominal silicon modified Fe-30Mn-9Al-0.9C-0.5Mo alloy for ballistic use. Castability was addressed first as this information was crucial for making test coupons and assisting foundries with production of MIL-PRF-32269 ballistic test plates. Four silicon concentrations were investigated for fluidity, microstructure, liquidus, solidus and dendrite coherency point. Silicon was added because it is known to increase fluidity of other ferrous alloys and has also been shown to eliminate a brittle ß-Mn phase in wrought Fe-Mn-Al-C alloys. Of the four silicon modified fluidity compositions, two were selected for heat treat property evaluation on the basis of microstructure. Hardness, strength, and ductility were measured (hardness is the only MIL-PRF-32269 measured property). The alloy with the highest ductility was selected for high strain rate evaluation. The strain rate testing results were the final means to lock in the alloy composition and heat treatment for solid plate ballistic testing. While conducting V₅₀ ballistic testing, phosphorus content was correlated to ballistic impact energy. Further testing was conducted to examine phosphorus, quench sensitivity, and aging Charpy V-Notch effects. The culmination of this thesis work resulted with positive ballistic threat testing revealing the alloy investigated here meets the Army\u27s MIL-PRF-32269 ballistic requirements and reduces P900 weight by 13% --Abstract, page iv

    Realization of an all-optical zero to π cross-phase modulation jump

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    We report on the experimental demonstration of an all-optical π cross-phase modulation jump. By performing a preselection, an optically induced unitary transformation, and then a postselection on the polarization degree of freedom, the phase of the output beam acquires either a zero or π phase shift (with no other possible values). The postselection results in optical loss in the output beam. An input state may be chosen near the resulting phase singularity, yielding a pi phase shift even for weak interaction strengths. The scheme is experimentally demonstrated using a coherently prepared dark state in a warm atomic cesium vapor

    The State of e-New Zealand: 2004

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    This State of E-New Zealand paper revisits the relative international measures of New Zealand's preparedness to utilise and capitalise upon the economic and social benefits promised by the use of technology. In the previous paper the authors concluded that New Zealand remained at the forefront of practically all electronic infrastructure indicators measured. Four years from the initial findings this paper concludes that New Zealand's relative ability to use its infrastructure to gain productive advantage is decreasing. Although it is well prepared in infrastructure New Zealand has slipped from its early leadership position relative to other countries in many as the information and communication technology market indicators as the New Zealand market approaches maturity and other countries catch up

    To have in order to do: Exploring the effects of consuming experiential products on well‐being

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    The experience recommendation – if you want to be happier, buy life experiences instead of material items – is supported in empirical research. However, this evidence is primarily based on the dichotomous comparison of material items and life experiences. The goal of this article is to examine the effects of consuming experiential products – purchases that fall between material items and life experiences – on well‐being. Study 1 and Study 2 demonstrate that experiential products provide similar levels of well‐being compared to life experiences and more well‐being than material items. Study 3 replicates this finding for purchases that turn out well. In addition, Study 3 shows experiential products, when compared to life experiences, lead to more feelings of competence but less feelings of relatedness, which explains why these two purchases result in similar levels of well‐being. We discuss why experiential products and life experiences lead to psychological need satisfaction and how our results support the Positive‐Activity Model, Self‐Determination Theory, and Holbrook and Hirschman’s hedonic consumption framework.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142004/1/jcpy28.pd

    Do You Feel Financially Secured? The Investigation of Economic Indicators and Consequences of Financial Well-Being

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    The economy has been in downward movement in the past few years in the United States as well as different parts of the world. Consumers’ financial situations have been found to influence their purchase behaviors. While some personal finance experts blame consumers’ (lack of) spending plans for their financial situations, others suggest that consumers’ perception of their financial standing influences their purchase plans. Using two nationwide large scale survey studies, we investigated how the consumer’s financial well-being affects planned and unplanned purchasing decisions from two competing perspectives. Supporting our notion of financial well-being as a status, the results revealed consumers with high financial well-being are more likely to make planned purchases and less likely to make unplanned purchases. We also examined the value of applying economic indicators as proxy measure of financial well-being. Instead of income or debts, wealth was found to be the most important economic indicator of financial well-being

    Do You Feel Financially Secured? The Investigation of Economic Indicators of Financial Well-Being

    Get PDF
    The economy has been in downward movement in the past few years in the United States as well as different parts of the world. Consumers’ financial situations have been found to influence their purchase behaviors. While some personal finance experts blame consumers’ (lack of) spending plans for their financial situations, others suggest that consumers’ perception of their financial standing influences their purchase plans. Using a nationwide large scale survey study, we examined the value of applying economic indicators as proxy measure of financial well-being. Instead of income or debts, wealth was found to be the most important economic indicator of financial well-being
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