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A novel vector algorithm for Reed-Muller (RM) expansions is proposed which can save as many as a factor of 2n-1 memory elements compared with previous matrix algorithms 相似文献
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HE Montgomery P Clarkson CM Dollery K Prasad MA Losi H Hemingway D Statters M Jubb M Girvain A Varnava M World J Deanfield P Talmud JR McEwan WJ McKenna S Humphries 《Canadian Metallurgical Quarterly》1997,96(3):741-747
PURPOSE: To determine the radiologic characteristics of cystic dystrophy of the duodenal wall. MATERIALS AND METHODS: Ten patients with cystic dystrophy of the duodenal wall and chronic pancreatitis underwent ultrasonography (US) (n = 10), computed tomography (CT) (n = 10), endoscopic US (n = 5), and endoscopic retrograde cholangiopancreatography (ERCP) (n = 9). Cystic dystrophy of the duodenal wall was classified as either cystic or solid. The imaging findings were retrospectively analyzed and compared with findings at pancreatoduodenectomy (n = 10). RESULTS: The more frequent cystic type (n = 7) of cystic dystrophy of the duodenal wall was characterized by the presence of easily recognizable cystic lesions (diameter, more than 1 cm), located within the thickened wall of the second portion of the duodenum. The solid type (n = 3) of cystic dystrophy of the duodenal wall demonstrated fibrous thickening of the duodenal wall within which small cysts (diameter, less than 1 cm) were present. The intraduodenal cysts were usually elongated or bilobate with a thick wall. The thickening of the duodenal wall appeared as a solid layer between the duodenal lumen and the pancreas, hypoechoic at US, isoattenuating at unenhanced CT, and hypoattenuating in the early phase (after initiation of infusion of contrast material) and isoattenuating in the late phase (after completion of infusion) at contrast material-enhanced CT. Findings at retrospective analysis of CT and endoscopic US images were characteristic. CONCLUSION: Imaging modalities, notably CT and endoscopic US, helped establish the diagnosis of cystic dystrophy of the duodenal wall. 相似文献
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Spread-spectrum modulation can be used in a radio system to reduce the likelihood of intercept, as well as providing some protection against jamming and interference. These antijam, anti-interference and low-probability-of-intercept properties are highly desirable in secured communication systems. In addition, spread-spectrum techniques have been proposed to combat spectral congestion by improving the efficiency of spectrum utilisation. Spread-spectrum techniques are also widely used in ranging systems and in local-area networks (LANs) or other multiple-access systems. In the present article, the three main spread-spectrum techniques are outlined and then applications of frequency-hopping systems and some of the techniques used are described 相似文献
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We report the first experimental study of the NMR lineshape anisotropy in the orientationally ordered cubic phase of a D2 single crystal. The para-D2 concentration covered the range 0.72<X<0.82. The observed line shapes were obtained by means of Fourier transform techniques from the solid echoes recorded with a pulsed NMR spectrometer operating at 5.9 MHz. Theoretical line shapes and their second moments forp-D2 (with angular momentumJ=1 and spinI=1) and foro-D2 (withJ=0, I=2) were calculated as a function of the applied field direction from the theory by A. B. Harris. Good agreement was obtained for all directions, provided that, just as for solid H2, a Gaussian function for the distribution of molecular axial alignment was assumed with an rms spreading angle of 6 deg forX=0.77. No change in the anisotropy of the second moment in the disordered phase was detected between the initial (hcp) crystal and after repeated thermal cyclings through the martensitic transition. This result implies no change in the orientation of the plane for the sliding nets during repeated passages through the transition. Furthermore, we report measurements of the longitudinal relaxation time for bothp-D2 ando-H2 versusT over the temperature range 0.5<T<3.5 K. The complex behavior reported previously for both H2 and D2 was confirmed. Measurements of the relaxation times as a function of the applied field direction in the ordered phase at 1.2 K showed no anisotropy within experimental error, and this result is discussed in the light of predictions by Hardy and Berlinsky. Finally, the polarization of theJ=0 molecules is studied as a function of the concentrationX of theJ=1 molecules and their state of orientational order over a wide range ofX andT in the ordered and disordered states. The results are compared with predictions of A. B. Harris and with previous data on polycrystalline samples. 相似文献
8.
Ferroelectrically Gated Atomically Thin Transition‐Metal Dichalcogenides as Nonvolatile Memory 下载免费PDF全文
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Dorothy Clarkson 《Cryptologia》2013,37(3):209-216
We describe the life and times of a servicing mechanic for cypher equipment for the Royal Air Force during World War II and an opportunity to serve again as a cypher machine restorer for Bletchley Park Museum. 相似文献
10.
S. D. Waller P. M. Langdon P. J. Clarkson 《Universal Access in the Information Society》2010,9(3):195-207
Exclusion auditing is a process that can quantitatively evaluate the inclusive merit of different products, or alternative
design decisions. The results from such an audit can provide prioritised directions for product improvement and support the
business case for reducing the capability levels required to use mainstream products. The 1996/1997 disability follow-up survey,
conducted by the Office of National Statistics, is currently the most comprehensive data source for estimating design exclusion
in the UK. In this paper, the data source is explained in detail, and a method is presented that uses this data to estimate
the exclusion associated with several tasks that occur in series or in parallel, illustrated through worked examples. Having
evaluated how many people are excluded, one can investigate why they were excluded, thus generating design insights into how
they could be included. Data from the survey is also converted to a series of stylised graphs, which are intended to inspire
designers to think about the relationship between the demands required to use a product and the resulting levels of population
exclusion. 相似文献