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1.
We have performed numerical calculations of the noise in voltage-biased superconducting transition edge-based X-ray microcalorimeters, using a finite-element model. Details of the model are discussed, as well as results for different absorber geometries. The results are in agreement with an analytical model and show that the amount of internal thermal fluctuation noise can be reduced by using a segmented absorber. The simulation also agrees well with experimental data, which, for our detectors, contain no major unidentified noise sources. Furthermore, the discrepancy between the (small-signal) theoretical and the measured energy resolutions for 5.9 keV X-rays, for our sensors typically a factor of 2, is explained by a more accurate modelling of the sensor responsivity, taking into account the large signal behaviour.  相似文献   
2.
Although packet delay and loss are two important parameters of the Internet performance, to the best of our knowledge, the evolution of large‐scale IPv6 delay and loss performance has previously not been studied. In this paper, we analyze more than 600 end‐to‐end IPv6 paths between about 26 testboxes of RIPE Network Coordination Centre over two years, and compare the delay and loss performance over time with their IPv4 counterparts. We present and discuss the measurement methodologies and show that IPv6 paths have a higher delay and loss than their IPv4 counterparts. The main reason for the worse performance stems from IPv6‐in‐IPv4 tunnels rather than from native IPv6 paths and such tunnels are still widely used today. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
3.
Summary Linear discriminant analysis of GLC-aromagram data is used to separate several classes of wine distillates, namely cognac, armagnac and brandy. In this paper we demonstrate how this method was used to detect adulteration. The adulteration was confirmed by the presence of ethyl heptanoate and limonene, which are well-known flavour compounds. They were analysed by means of a Purge and Trap headspace technique. Mass spectrometry was used to identify these flavours.
Ein Beispiel für die Verfälschung von Cognac
Zusammenfassung Die Linear-Discriminanz-Analyse von GLC-Aromagramm-Daten wird zur Klassifizierung von Weindestillaten wie Cognac, Armagnac und Brandy verwendet. In dieser Arbeit werden mit dieser Methode Verfälschungen nachgewiesen, die durch die Gegenwart der Ethylester der Heptansäure und des Limonen belegt werden konnten. Diese Substanzen wurden mit der Purge- und Trap-Methode erfaßt und massenspektrometrisch identifiziert.
  相似文献   
4.
Ewing's sarcoma is a highly malignant neoplasm of the bone whose origin is still uncertain. A strong relationship exists between Ewing's sarcoma and tumors of neural origin (Ewing family of tumors). Ewing's sarcoma must be distinguished from other round-cell tumors like lymphoma and neuroblastoma and also must be differentiated from osteogenic sarcomas. On plain radiographs, Ewing's sarcoma appears as a lytic or mixed lytic-sclerotic, rarely as predominantly sclerotic lesion with margins Lodwick grade III. It is located primarily in the diaphyseal and metadiaphyseal regions of the long bones of the lower extremities. A large soft tissue tumor is usually present. Magnetic resonance imaging is the imaging modality of choice to evaluate the extent of the primary lesion, to monitor the response to neoadjuvant chemotherapy and to follow up non-resected Ewing's sarcomas. Bone scintigraphy is necessary to detect skeletal metastasis, and 201thallium scanning has been shown to be sensitive in the monitoring of treatment response. Today, computed tomography is not longer used to image the tumor site; however, spiral CT of the lungs plays a central role as a staging and follow-up tool.  相似文献   
5.
On the basis of the idea that situational norms are mentally represented as associations between environments and normative behavior, it was proposed that an environment can automatically direct normative behavior. More specifically, when situational norms are well-established (e.g., when entering the library, one should be silent), an environment is capable of automatically activating mental representations of normative behavior and the behavior itself. In these experiments, participants were exposed to pictures of environments, and effects on accessibility of representations of normative behavior and on actual behavior were assessed. Results indicated that representations of behavior and actual behavior itself are activated automatically when (a) goals to visit the environment are active and (b) strong associations between environment and normative behavior are established. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
Organic solvent nanofiltration (OSN) is gradually expanding from academic research to industrial implementation. The need for membranes with low and sharp molecular weight cutoffs that are able to operate under aggressive OSN conditions is increasing. However, the lack of comparable and uniform performance data frustrates the screening and membrane selection for processes. Here, a collaboration is presented between several academic and industrial partners analyzing the separation performance of 10 different membranes using three model process mixtures. Membrane materials range from classic polymeric and thin film composites (TFCs) to hybrid ceramic types. The model solutions were chosen to mimic cases relevant to today's industrial use: relatively low molar mass solutes (330–550 Da) in n-heptane, toluene, and anisole.  相似文献   
7.
In this paper we address the safety analysis of chemical plants controlled by programmable logic controllers (PLCs). We consider a specification of the control program of the PLCs, extended with the specification of the dynamic plant behavior. The resulting hybrid models can be transformed to hybrid automata, for which advanced techniques for reachability analysis exist. However, the hybrid automata models are often too large to be analyzed. We propose two counterexample-guided abstraction refinement (CEGAR) approaches to keep the size of the hybrid models moderate.  相似文献   
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9.
It is well known that help prompts shape how users talk to spoken dialogue systems. This study investigated the effect of help prompt placement on older users’ interaction with a smart home interface. In the dynamic help condition, help was only given in response to system errors; in the inherent help condition, it was also given at the start of each task. Fifteen older and sixteen younger users interacted with a smart home system using two different scenarios. Each scenario consisted of several tasks. The linguistic style users employed to communicate with the system (interaction style) was measured using the ratio of commands to the overall utterance length (keyword ratio) and the percentage of content words in the user’s utterance that could be understood by the system (shared vocabulary). While the timing of help prompts did not affect the interaction style of younger users, it was early task-specific help supported older users in adapting their interaction style to the system’s capabilities. Well-placed help prompts can significantly increase the usability of spoken dialogue systems for older people.  相似文献   
10.
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