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Dongsu Kim Yoonsu Choi Ahn M. Allen M.G. Stevenson Kenney J. Marry P. 《Microwave and Wireless Components Letters, IEEE》2003,13(10):434-436
Continuously variable ferroelectric (BST on sapphire) phase shifters based on all-pass networks are presented. An all-pass network phase shifter consists of only lumped LC elements, and thus the total size of the phase shifter is kept to less than 2.2 mm /spl times/ 2.6 mm at 2.4 GHz. The tunability (C/sub max//C/sub min/) of a BST interdigital capacitor is over 2.9 with a bias voltage of 140 V. The phase shifter provides more than 121/spl deg/ phase shift with the maximum insertion loss of 1.8 dB and the worst case return loss of 12.5 dB from 2.4 GHz to 2.5 GHz. By cascading two identical phase shifters, more than 255/spl deg/ phase shift is obtained with the maximum insertion loss of 3.75 dB. The loss figure-of-merit of both the single- and double-section phase shifters is over 65/spl deg//dB from 2.4 GHz to 2.5 GHz. 相似文献
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SA Cleaver P Warren M Kern CK Hurley C Raffoux J Keller U Kiesel V Koza E Marry A Mitterschiffthaler M Nakamura CT Okah U Persson T Radde-Stepaniak L Ranson J Raymond M do Rosario Sancho M Varla-Leftherioti T Wiegand JM Winterhager DG Woodfield 《Canadian Metallurgical Quarterly》1997,20(8):621-629
In October 1995 the World Marrow Donor Association (WMDA) was restructured in order to facilitate its primary function of establishing guidelines in relation to international bone marrow and blood stem cell transplants -- transplants in which the donor is in one country and the patient is in another country. Five new working groups were established -- Donor Registries, Ethics, Quality Assurance, Finances, and Stem Cells. This paper, prepared by members of the Donor Registries Working Group, in consultation with the Quality Assurance Working Group, provides recommendations for the 'donor work-up'. This term covers events that start when the definitive donor has been identified, includes the harvesting (collection) and transportation of the stem cell product and ends when the product reaches the transplant centre. The paper includes examples of the documentation intended to ensure compliance with the recommendations at all key points in the sequence. 相似文献
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Rattikorn Hewett Phongphun Kijsanayothin Stephanie Bak Marry Galbrei 《Applied Intelligence》2016,45(1):83-95
Cybersecurity is a growing concern in today’s society. Security policies have been developed to ensure that data and assets remain protected for legitimate users, but there must be a mechanism to verify that these policies can be enforced. This paper addresses the verification problem of security policies in role-based access control of enterprise software. Most existing approaches employ traditional logic or procedural programming that tends to involve complex expressions or search with backtrack. These can be time-consuming, and hard to understand, and update, especially for large-scale security verification problems. Declarative programming paradigms such as “Answer Set” programming have been widely used to alleviate these issues by ways of elegant and flexible modeling for complex search problems. However, solving problems using these paradigms can be challenging due to the nature and limitation of the declarative problem solver. This paper presents an approach to automated security policy verification using Answer Set programming. In particular, we investigate how the separation of duty security policy in role-based access control can be verified. Our contribution is a modeling approach that maps this verification problem into a graph-coloring problem to facilitate the use of generate-and-test in a declarative problem-solving paradigm. The paper describes a representation model and rules that drive the Answer Set Solver and illustrates the proposed approach to securing web application software to assist the hiring process in a company. 相似文献
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This paper describes a new method for scanning the conductivity of a tissue or an organ using a multielectrode impedance probe placed at the center of the region of interest. The long-term objective of the study is the evaluation, using an urethral impedance probe, of the lesion produced by ultrasound ablathermy of localized prostate cancer. The probe consists of electrodes placed at the surface of an insulating cylinder. The injected current passes around the cylinder and spreads in the medium surrounding the probe. This paper presents the theoretical bases of this method, the calculated sensitivity distributions of electrode configurations involving a pair of diametrically opposed electrodes and an application in vitro. The experimental set-up consisted of a water tank and a 16-electrode prototype probe 50 mm in diameter. Data sets were collected in the presence of conductivity perturbations produced by small size insulators or conductors and a 7.5% constant perturbation model. The presented images, although reconstructed using a simple retro-projection algorithm, demonstrate the feasibility of the method. Improvements in data collection and image reconstruction are possible. 相似文献
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Marry V Dubois E Malikova N Durand-Vidal S Longeville S Breu J 《Environmental science & technology》2011,45(7):2850-2855
Within the wider context of water behavior in soils, and with a particular emphasis on clays surrounding underground radioactive waste packages, we present here the translational dynamics of water in clays in low hydrated states as studied by coupling molecular dynamics (MD) simulations and quasielastic neutron scattering experiments by neutron spin echo (NSE). A natural montmorillonite clay of interest is modeled by a synthetic clay which allows us to understand the determining parameters from MD simulations by comparison with the experimental values. We focus on temperatures between 300 and 350 K, i.e., the range relevant to the highlighted application. The activation energy Ea experimentally determined is 6.6 kJ/mol higher than that for bulk water. Simulations are in good agreement with experiments for the relevant set of conditions, and they give more insight into the origin of the observed dynamics. 相似文献
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R. Lichtenthler P. Foury J. C. Angelique P. Bertrand B. Blank O. Bajeat L. Boy M. Ducourtieux P. Jardin N. Lecesne A. Lpine-Szily M. Lewitowicz C. F. Liang M. Loiselet H. Lefort R. Leroy J. Mandin C. Marry L. Maunoury J. Obert N. Orr J. Y. Pacquet J. C. Putaux G. Ryckewaert E. Robert M. G. Saint-Laurent P. Sortais M. Toulemonde I. Tirrel A. C. C. Villari 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1998,140(3-4)
We developed a model and a computer program to calculate the temperature distribution in the target which will be used in the SPIRAL project a GANIL. The results of the numerical simulation are compared with measurements performed with several types of targets. 相似文献
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Mazz Marry Maureen C McCann Frank Kolpak Alan R White Nicola J Stacey Keith Roberts 《Journal of the science of food and agriculture》2000,80(1):17-28
Previous methods of extracting pectin from sugar‐beet have used pulp as the starting material. As the temperature and pressure of the pulping process may modify the architecture of the cell wall, we have adapted a relatively non‐disruptive method to characterise cell wall material (CWM) isolated directly from the sugar‐beet. Cell walls from mature sugar‐beets (Beta vulgaris L Aztec) were sequentially extracted four times with imidazole and twice with sodium carbonate to produce six heterogeneous pectic polysaccharide extracts, and with KOH to produce a hemicellulosic extract which was predominantly xylans. Heterogeneity of the extracted pectins was indicated by differences in FTIR spectra, uronic acid content, % methyl esterification, % feruloylation, % acetylation, molecular weight distribution and neutral sugar composition. The highest proportion of feruloyl esters was found in polysaccharides solubilised by the second sodium carbonate extraction. Anion exchange chromatography of these polysaccharides gave three fractions, one of which contained most of the feruloyl ester. These results indicate that feruloyl esters are not randomly distributed among the different pectic polysaccharides in the sugar‐beet cell wall, and that esterification is likely to be dependent on the local sugar sequence or conformation. © 2000 Society of Chemical Industry 相似文献
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