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171.
Ning GX Aditya S Shum P Liu N Gong YD Lu C 《Journal of the Optical Society of America. A, Optics, image science, and vision》2005,22(5):913-916
We propose and experimentally demonstrate a novel and simple photonic microwave notch filter that uses a high-birefringent fiber that gives a fixed differential group delay (DGD), together with a DGD element that gives a tunable DGD. This configuration overcomes the problems of optical coherence interference and chromatic dispersion, which may occur in schemes that use fiber delay lines or fiber gratings. Also presented is a theoretical analysis for the performance of the microwave filter that uses the present configuration. The present scheme provides a continuous tuning capability for changing the notch frequency. Measured notch rejection is greater than 40 dB. This scheme can operate over a wide wavelength range of the optical carrier. There is good agreement between experiment results and theoretical analysis. 相似文献
172.
Mayora Varshney Aditya Sharma Ravi Kumar K.D. Verma 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(23):2786-2791
Nanoparticle formation in the, rf-sputtering grown, polycrystalline CeO2 thin films is achieved by the swift heavy ion (SHI) irradiation. Crystal structure and phases present in the as-grown and irradiated thin films are investigated by the X-ray diffraction (XRD) measurements. Irradiation induced formation of spherically shaped nanostructures, on the film surface, is confirmed by the atomic force microscopy (AFM). The Raman spectra of the irradiated samples show increased line-width and peak position shifting in the Raman active mode (F2g) of CeO2, indicative of the nanocrystallization in the irradiated CeO2 thin films. Formation of nanostructures in the irradiated samples is also briefly discussed in the light of ion energy and energy loss mechanisms. 相似文献
173.
Ning G Shum P Aditya S Gong Y 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(1):188-191
We propose a continuously tunable, dual free spectral range (FSR) photonic microwave notch filter configuration using a high-birefringence linearly chirped fiber Bragg grating (Hi-Bi LCFBG) that is connected in a Sagnac loop using a Hi-Bi coupler. The configuration employs double sideband modulation and can generate two FSRs simultaneously. The larger FSR corresponds to the differential time delay of the Hi-Bi LCFBG and the Hi-Bi pigtails of the coupler; the smaller FSR corresponds to the time delay between the arms of the Sagnac loop. Measured results demonstrate dual FSR, a large notch rejection, and that the FSR is easily tunable by tuning the LCFBG. We also present the filter transfer function for the design. Experimental results agree well with the theoretical analysis. 相似文献
174.
Journal of Computer Virology and Hacking Techniques - Effective and efficient malware detection is at the forefront of research into building secure digital systems. As with many other fields,... 相似文献
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Shuhei Nakakura Aditya Farhan Arif Febrigia Ghana Rinaldi Tomoyuki Hirano Eishi Tanabe Ratna Balgis Takashi Ogi 《Advanced Powder Technology》2019,30(1):6-12
The metastable state hexagonal-tungsten oxide (h-WO3) has been attracting attention over the past decade because of its high reactivity that arises from the hexagonal channels in its crystal structure. Simplification of the process used to synthesize h-WO3 is an important step to facilitate the industrial applications of this material. In this study, we addressed this challenge by developing a spray pyrolysis process to synthesize highly crystalline h-WO3. The ratio of the monoclinic to the hexagonal phase was controlled by adjusting the segregation time. Single-phase h-WO3 nanorods were synthesized using a carrier gas flow rate of 1?L/min, which was equivalent to a segregation time of 18.4?s. The ability of the h-WO3 nanorods to adsorb nitrogen and carbon dioxide was evaluated to confirm the presence of hexagonal channels in the crystal structure. 相似文献
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Aditya K. Ghose Pablo O. Hadjinian Abdul Sattar Jia-H. You Randy Goebel 《Computational Intelligence》2004,20(1):37-55
Most existing formalizations treat belief change as a single-step process, and ignore several problems that become important when a theory, or belief state, is revised over several steps. This paper identifies these problems, and argues for the need to retain all of the multiple possible outcomes of a belief change step, and for a framework in which the effects of a belief change step persist as long as is consistently possible. To demonstrate that such a formalization is indeed possible, we develop a framework, which uses the language of PJ-default logic (Delgrande and Jackson 1991) to represent a belief state, and which enables the effects of a belief change step to persist by propagating belief constraints . Belief change in this framework maps one belief state to another, where each belief state is a collection of theories given by the set of extensions of the PJ-default theory representing that belief state. Belief constraints do not need to be separately recorded; they are encoded as clearly identifiable components of a PJ-default theory. The framework meets the requirements for iterated belief change that we identify and satisfies most of the AGM postulates (Alchourrón, Gärdenfors, and Makinson 1985) as well. 相似文献
180.
Solutions are given to a number of asymmetric Stokes-flow problems which involve the slow motion of a fluid in the presence of a rigid plane containing a circular hole. The particular instances of motion generated by a linear shear flow along the plane and by a Stokeslet, placed on the axis of symmetry of the hole and oriented perpendicular to this axis, are examined in detail. The paper concludes with a solution to the shear-flow problem when the circular hole is replaced by one of elliptical geometry. 相似文献