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51.
Information Systems Security (ISS) has constantly been ranked as a key concern for Information Systems (IS) managers. Research in the field has largely assumed rational choice (functional) approaches to managing ISS. Such approaches do not give due recognition to the role of improvisation in ISS work. Empirical evidence in organisations suggests that in the context of dynamic, volatile and uncertain environments practitioners are both rational and adaptive (a manifestation of improvisation). In this paper, we conceptualise and demonstrate the manifestation of improvisation in ISS. In order to develop a better understanding of improvisation in ISS activities, hermeneutical and exegetical techniques were employed. Empirical data were collected through in-depth interviews in a single case study. The data obtained were analysed and interpreted hermeneutically. Generally it was found that improvisation is manifested in ISS activities. Implications of these and other findings for the scholarly community and for practical use are discussed.  相似文献   
52.
53.
A model is proposed for mixed-mode crack propagation in materials which show shear lips on the fracture surface. The model is shown to predict the existance of a brittle-ductile transition as the specimen thickness is decreased. The predictions of the model are compared with published experimental data on a number of polymers including polycarbonate, and good agreement is found.  相似文献   
54.
55.
A novel technique to monitor the synthesis process of encapsulated acetylacetonatocarbonyl triphenylphosphinerhodium within a microsilica nanoshell has been studied using inductively coupled plasma (ICP) techniques. Nanospheres sized around 50-100 nm were obtained and ICP was used to quantify the exact composition of rhodium, phosphorous, and silicon with differing digestion solvents. In addition, ICP was used to detect rhodium and phosphorous in the nano core-shell catalysts as a quality control procedure  相似文献   
56.
Nanoengineered fluorescent sensor coatings on colloidal carriers have been developed for use intracellularly. These nanosensors are fabricated via the electrostatic layer-by-layer self-assembly technique to form ultrathin polyelectrolyte films containing indicators on fluorescent nanoparticles. The fluorescent nanoparticle templates and the fluorescent indicator are chosen such that their optical properties are complementary, enabling the inert nanoparticle templates to serve as internal intensity references for the fluorescent probe. In this work, the potassium ion indicator, potassium-binding benzofuran isophthalate potassium-binding benzofuran isophthalate was immobilized within poly(styrene sulfonate)/poly(allylamine hydrochloride) films assembled on the surface of fluorescent europium nanoparticles. The indicator retains its sensitivity to potassium ions after immobilization within the films and exhibits sensitivity to increases in potassium concentration over a broad range. In addition, the sensors demonstrate excellent leaching stability, with less than 1% of loaded indicator leached after 14 days of wet storage. The core-referenced nanosensor scheme described here is a simple and elegant way to co-immobilize fluorescent indicator and intensity reference within a single nanoscale package, which may be deployed intracellularly; furthermore, the separation of fluorescent indicator from the cellular environment is attractive, as it may prevent complications due to use of liquid-phase fluorescent sensors intracellularly, such as cytotoxicity and probe compartmentalization.  相似文献   
57.
研究了贝叶斯频谱估计的基本理论和基本方法 ,分别对无噪声和有噪声的简谐正弦信号进行了频谱估计。计算结果显示 :无噪声信号频率估计偏倚为零 ;当信号噪声系数S/N =1时 ,贝叶斯频率估计的偏倚与Jaynes的理论值一致  相似文献   
58.
This study examined the hypothesis that psychotic, borderline, and neurotic personality organizations (POs) present a progressive differentiation between self and object representations and an increasing integration of their bad and good aspects. Fifty patients participated in the study. Measures included scales of self and object representations (S. J. Blatt, S. A. Bers, & C. E. Schaffer, 1993; S. J. Blatt, H. Wiseman, E. Prince-Gibson, & C. Gatt, 1991), as well as the Personality Organization Diagnostic Form (L. Diguer & L. Normandin, 1997) and estimations of psychiatric severity. Results showed that PO groups differed in terms of the integration of the object and its valence. It was also observed that although object and self representations were closely intertwined, the latter showed more discrimination between POs than the former. Psychiatric severity was shown to correlate more with object representations than self representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
59.
Despite oxycodone's (4,5-epoxy-14-hydroxy-3-methoxy-17-methylmorphinan-6-one) history of clinical use and the attention it has received as a drug of abuse, few reports have documented its pharmacology's relevance to its abuse or its mechanism of action. The purposes of the present study were to further characterize the analgesic effects of oxycodone, its mechanism of action, and its effects in terms of its relevance to its abuse liability. The results indicate that oxycodone had potent antinociceptive effects in the mouse paraphenylquinone writhing, hot-plate, and tail-flick assays, in which it appeared to be acting as a μ-opioid receptor agonist. It generalized to the heroin discriminative stimulus and served as a positive reinforcer in rats and completely suppressed withdrawal signs in morphinedependent rhesus monkeys. These results suggest that the analgesic and abuse liability effects of oxycodone are likely mediated through μ-opioid receptors and provide the first laboratory report of its discriminative stimulus, reinforcing, and morphine cross-dependency effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
60.
A low-cost,high-performance pulse generator for ultrasound imaging   总被引:2,自引:0,他引:2  
The design of a low-cost pulse generator for ultrasound imaging is presented. The pulser can provide 10 kW pulses with less than 0.7 Vpp ringing. Pulses ranging from 10 to 500 ns have been successfully generated  相似文献   
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