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The separation of 12 explosives by capillary electrophoresis was optimized with the aid of artificial neural networks (ANNs). The selectivity of the separation was manipulated by varying the concentration of sodium dodecyl sulfate (SDS) and the pH of the electrolyte, while maintaining the buffer concentration at 10 mM borate. The concentration of SDS and the electrolyte pH were used as input variables and the mobility of the explosives were used as output variables for the ANN. In total, eight experiments were performed based on a factorial design to train a variety of artificial neural network architectures. A further three experiments were required to train ANN architectures to adequately model the experimental space. A product resolution response surface was constructed based on the predicted mobilities of the best performing ANN. This response surface pointed to two optima; pH 9.0-9.1 and 60-65 mM SDS, and pH 8.4-8.6 and 50-60 mM SDS. Separation of all 12 explosives was achieved at the second optimum. The separation was further improved by changing the capillary to an extended cell detection window and reducing the diameter of the capillary from 75 microm to 50 microm. This provided a more efficient separation without compromising detection sensitivity. 相似文献
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The recent introduction of the New Generation, podular/direct supervision philosophy of jail architecture and inmate management dramatically changes the nature and design of the work performed by custodial staff. In particular, the new philosophy has the potential to "enrich" the job of correctional officers. Using before and after data gathered a t one institution, we address whether job enrichment is an outcome of the transition from traditional to podular/direct supervision detention facility design, and whether enrichment of the job affects employee perceptions of the work and of the organization. 相似文献
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Ben Agger 《Democracy & Nature》2001,7(1):183-203
I argue that we need to view texts and all cultural products and practices as having been authored but simultaneously as constrained by the culture industry and its literary political economies. This theoretical apperception affords a social theory of the text that combines insights from German critical theory and French postmodern theory. Viewing the inherence of reading and writing in the social allows us to conceive of strategies that liberate authors and all cultural producers from domination while keeping in mind that language will always be a prison house of sorts, captured in Derrida's notion of undecidability. Developing a social theory of the text is especially important in the era of the internet and Web, when cultural production and transmission are opened up to many writers and readers. 相似文献
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R&D laboratories in the United States have during the past decade undergone much structural and environmental change. Much of this change has been in response to public policy initiatives and changing markets. One result of the changing environments of R&D laboratories is that traditional sector-based (government, industry, university) classification of laboratories tells us little about their structure and behavior. This study based on survey data derived from 966 U.S. R&D laboratories, develops an environmental input taxonomy, based not on sector but on the mix of political and market influence on laboratories. This taxonomy is examined in connection with three central policy issues: amount of cooperative research, red tape and bureaucratization, and laboratory output. Traditonal sector classification accounts well for red tape, but the environmental input taxonomy provides additional insights into laboratories' scientific and technical output and cooperative research. 相似文献
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