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91.
H.T. Panduranga S.K. Naveen Kumar Kiran 《The European physical journal. Special topics》2014,223(8):1663-1677
In this paper we presented a image encryption based on permutation-substitution using chaotic map and Latin square image cipher. The proposed method consists of permutation and substitution process. In permutation process, plain image is permuted according to chaotic sequence generated using chaotic map. In substitution process, based on secrete key of 256 bit generate a Latin Square Image Cipher (LSIC) and this LSIC is used as key image and perform XOR operation between permuted image and key image. The proposed method can applied to any plain image with unequal width and height as well and also resist statistical attack, differential attack. Experiments carried out for different images of different sizes. The proposed method possesses large key space to resist brute force attack. 相似文献
92.
Ming-Fong Tsai Naveen Chilamkurti Ce-Kuen Shieh 《Wireless Personal Communications》2011,56(3):435-446
Video streaming over wireless networks is a challenging task due to its high error rate. Forward error correction (FEC) is
a popular mechanism to recover lost packets for video streaming. Conventional FEC mechanisms use a whole redundant packet
to recover the error source packet, when the packet error occurs with only a few bit errors inside. In this paper, we propose
an Adaptive packet and block length FEC (APB-FEC) control mechanism. In order to overcome the high bit error rate, a small
packet length reduces the packet error rate and a large FEC block length will enhance the recovery performance. Our proposed
APB-FEC can obtain better recovery performance than conventional FEC mechanisms. Hence, APB-FEC can also reduce retransmission
overhead. Using extensive emulations, we validate the efficiency of APB-FEC mechanism for video streaming over wireless networks. 相似文献
93.
J. R. Reddy G. Ravi Naveen Kumar Veldurthi Radha Velchuri Someshwar Pola Muga Vithal B. Sreedhar 《无机化学与普通化学杂志》2013,639(5):794-798
KSbWO6 was prepared by sol‐gel method. N‐doped KSbWO6 (KSbWO6–xNx) was obtained by heating KSbWO6 and urea at 400 °C. Both the compounds are characterized by powder X‐ray diffraction (XRD), TEM, SEM‐EDS, X‐ray photo electronic spectroscopy (XPS), and UV/Vis diffuse reflectance spectroscopy (UV‐DRS). A shift in the peak positions of powder XRD and XPS spectra was observed. The band gap energy (Eg) of KSbWO6 and N‐doped KSbWO6 was obtained from their diffused reflectance spectra.Eg was reduced from 3.17 eV to 2.56 eV upon nitrogen doping in KSbWO6. The reduction of the Eg is attributed to the lifting of valence band of N‐doped KSbWO6, due to the mixing of O 2p states with N 2p states. The photocatalytic activity of both the samples was studied by degradation of methylene blue (MB). The nitrogen doped KSbWO6 shows higher photocatalytic activity compared to that of KSbWO6. 相似文献
94.
Naveen Gautam Neha Ajmera Shikha Gupta Priyadarshi Meena Ashok Kumar D. C. Gautam 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2409-2417
This article describes the synthesis of 10H-phenothiazines from 2-aminobenzenethiol and o-halonitrobenzenes via Smiles rearrangement. Upon refluxing with hydrogen peroxide in glacial acetic acid, these phenothiazines yield the corresponding 10H-phenothiazine-5,5-dioxides. The phenothiazines have also been used as base to prepare ribofuranosides by the reaction with β-D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antioxidant and antimicrobial activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
95.
The Chaperone‐like Activity and Structure of Mutant H119G of Rat Lens αB‐crystallin: A Study of Divalent Metal Ion Binding Site 下载免费PDF全文
The molecular chaperone αB‐crystallin, the major player in maintaining the transparency of the eye lens, preventing the aggregation of stress‐damaged and aging lens proteins from aggregation. In nonlenticular cells, it is involved in various neurological diseases, diabetes, and cancer. The role of some metal ions in the αB‐crystallin biology has been reported. Theoretical calculations have proposed that the coordination sites involving His101, His119, Lys121, His18 and Glu99 of human αB‐crystallin were the binding sites for divalent metal ions. Our previous mutagenesis study suggested that His18 rat lens αB‐crystallin is a crucial binding site for Cu(II) and Zn(II) in terms of chaperone‐like activity and structure. In this study mutant H119G of rat lens αB‐crystalin was cloned and expressed to investigate whether His119 is the coordination binding site. Copper and zinc at 1 mM concentration significantly increase the chaperone‐like activity in wild type αB‐crystalin, whereas zinc, copper and magnesium at 1 mM reduced the activity of H119G significantly. The results from chaperone‐like activity, ANS fluorescence measurement and Far‐and Near‐UV CD studies suggest that the replacement of His119 with Glycine resulted in a conformational and minor environmental changes that decrease chaperone‐like activity in the presence of divalent ions suggested that His119 was a crucial binding site for Cu(II) and Zn(II), which was similar to our previous study results of His18. Both results together suggest that His18 and His119 coordinates each other for the binding site of Cu(II) and Zn(II) in terms of improving the chaperone‐like activity and stability of crystallin/metal ion complex. 相似文献
96.
We present a basic optical encryption architecture that admits several cryptography applications based on multiplexing. Users can decrypt different private images from the same encrypted image, a superuser can have a key that decrypts all encrypted images, and multiplexed images can be encrypted with different levels of security. This system is presented in the context of a general framework of optical encryption application development. We illustrate with a real-world three-dimensional scene, captured with digital holography, and encrypted using the fractional Fourier transform, where different users have access to different three-dimensional objects in the scene. 相似文献
97.
J. R. Reddy G. Ravi P. Suresh Naveen Kumar Veldurthi Radha Velchuri M. Vithal 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1321-1327
Single source precursor, antimony potassium tartrate, was used for the preparation of Sb2O3, KSb3O5, K0.51Sb 0.67 III Sb 2 V O6.26, and KSbO3. Antimony trioxide (Sb2O3) was prepared by hydrothermal method, while potassium antimony oxides (KSbO3, K0.51Sb 0.67 III Sb 2 V O6.26, and KSbO3) were obtained from the thermal decomposition of antimony potassium tartrate. All the compounds were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), UV–Vis diffuse reflectance spectra, and scanning electron microscopy (SEM). The decomposition process of antimony potassium tartrate with temperature was given. The product formation at different temperatures of thermal decomposition was monitored by PXRD and FT-IR. The TG profile of antimony potassium tartrate shows mass loss at three regions. The infrared spectra of parent and decomposed products gave characteristic Sb-O bands. The band gap energy of decomposed products was obtained. The SEM diagrams of Sb2O3 show different morphologies. Direct solid state preparation of KSb3O5 and K0.51Sb 0.67 III Sb 2 V O6.26 under identical experimental conditions was unsuccessful. 相似文献
98.
Naveen Kumar Bejjanki Akkaladevi Venkatesham Kammari Balraju Kommu Nagaiah 《Helvetica chimica acta》2013,96(8):1571-1578
The first stereoselective synthesis of the naturally occurring conjugated diyne oplopandiol is reported. The pivotal functionalities are derived from Cadiots? Chodkiewicz cross‐coupling reaction, Ohira? Bestmann alkynation, asymmetric Noyori reduction, and cis‐olefination reaction 相似文献
99.
K. Nagaiah V. Naveen Kumar R. Srinivasa Rao B. V. S. Reddy A. V. Narsaiah J. S. Yadav 《合成通讯》2013,43(22):3345-3352
The imines were generated in situ from carbonyl compounds and amines, which undergo smooth reduction with sodium borohydride in an ionic liquid/H2O solvent system. The reaction conditions were very mild and neutral to afford the corresponding highly functionalized amines in excellent yields. 相似文献
100.
In this paper, we implement a fully phase-encrypted memory system using cascaded extended fractional Fourier transform (FRT). We encrypt and decrypt a two-dimensional image obtained from an amplitude image. The full phase image to be encrypted is fractional Fourier transformed three times and random phase masks are placed in the two intermediate planes. Performing the FRT three times increases the key size, at an added complexity of one more lens. The encrypted image is holographically recorded in a photorefractive crystal and is then decrypted by generating through phase conjugation, the conjugate of the encrypted image. A lithium niobate crystal has been used as a phase contrast filter to reconstruct the decrypted phase image, alleviating the need of alignment in the Fourier plane making the system rugged. 相似文献