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排序方式: 共有915条查询结果,搜索用时 31 毫秒
41.
42.
Flexible Prime‐Field Genus 2 Hyperelliptic Curve Cryptography Processor with Low Power Consumption and Uniform Power Draw 下载免费PDF全文
This paper presents an energy‐efficient (low power) prime‐field hyperelliptic curve cryptography (HECC) processor with uniform power draw. The HECC processor performs divisor scalar multiplication on the Jacobian of genus 2 hyperelliptic curves defined over prime fields for arbitrary field and curve parameters. It supports the most frequent case of divisor doubling and addition. The optimized implementation, which is synthesized in a 0.13 μm standard CMOS technology, performs an 81‐bit divisor multiplication in 503 ms consuming only 6.55 μJ of energy (average power consumption is 12.76 μW). In addition, we present a technique to make the power consumption of the HECC processor more uniform and lower the peaks of its power consumption. 相似文献
43.
Crystallization kinetics of Fe55-xCr18Mo7B16C4Nbx(x= 0, 3) bulk amorphous alloys were analyzed using X-ray diffraction and differential scanning calorimetric (DSC) tests. In practice, crystallization and growth mechanism were evaluated using DSC tests at four different heating rates (10, 20, 30, and 40 K/min) and kinetic models. Two-step crystallization behavior was observed when Fe55Cr18Mo7B16C4 and Fe52Cr18Mo7B16C4Nb3 bulk amorphous alloys were annealed, where Fe36Cr12Mo10 phase was crystallized in the first step of crystallization. Results show that Fe36Cr12Mo10 and Fe3C phases were crystallized in the structures of the alloys after further annealing process. Activation energy for the crystallization of Fe36Cr12Mo10 phase was measured to be 543 kJ/mol in Fe52Cr18Mo7B16C4Nb3 alloy and 375 kJ/mol for Fe55Cr18Mo7B16C4 alloy according to Kissinger-Starink model. Moreover, a two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in Fe52Cr18Mo7B16C4Nb3 alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe36Cr12Mo10 phase dur- ing annealing of Fe55Cr18Mo7B16C4 alloy. TEM (transmission electron microscopy) observations reveal that crystalline Fe36Cr12Mo10 phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology. 相似文献
44.
Sonia Ahangar Ghader Rezazadeh Rasool Shabani Goodarz Ahmadi Alireza Toloei 《International Journal of Mechanics and Materials in Design》2011,7(4):327-342
In this paper, the size-dependent vibrational behavior of a microbeam conveying fluid was investigated using the Modified
Couple Stress Theory. For cantilever and clamped-clamped microbeams, the small amplitude vibration equation of the micro-beams
was solved using a Galerkin based reduced order model and the effects of material length-scale parameter on its natural frequencies
were evaluated. It was found that for the both cantilever and clamped-clamped conditions, the critical fluid velocities predicted
by the modified couple stress theory are higher than those predicted by the classical beam theory. In addition, the differences
between the eigen-frequencies and the critical fluid velocities predicted by the modified couple stress theory and classical
beam theory depends on the ratio of the material length-scale parameter to the beam height. In addition an unexpected result
in the difference between the first eigen-frequency of the cantilever micro-beam obtained by the classical and the modified
couple stress theory has been achieved. 相似文献
45.
S. M. Sadat Kiai M. Elahi S. Adlparvar E. Shahhoseini S. Sheibani H. Ranjber akivaj S. Alhooie A. Safarien S. Farhangi N. Aghaei S. Amini M. M. Khalaj A. R. Zirak A. A. Dabirzadeh J. Soleimani F. Torkzadeh M. M. Mousazadeh K. Moradi M. Abdollahzadeh A. Talaei A. A. Zaeem A. Moslehi A. Kashani A. R. Babazadeh F. Bagiyan M. Ardestani A. Roozbahani H. Pourbeigi H. Tajik Ahmadi M. A. Ahmadifaghih M. S. Mahlooji B. N. Mortazavi F. Zahedi 《Journal of Fusion Energy》2011,30(2):111-115
Modified IS (Iranian Sun) plasma focus (10 kJ,15 kV, 94 ??F, 0.1 Hz) has been used to produce the short-lived radioisotope 13N (half-life of 9.97 min) through 12C(d,n)13N nuclear reaction. The filling gas was 1.5?C3 torr of hydrogen (60%) deuterium (40%) mixture. The target was solid nuclear grade graphite with 5 mm thick, 9 cm width and 13 in length. The activations of the exogenous target on average of 20 shots (only one-third acceptable) through 10?C13 kV produced the 511 keV gamma rays. Another peak found at the 570 keV gamma of which both was measured by a NaI portable gamma spectrometer calibrated by a 137Cs 0.25 ??Ci sealed reference source with its single line at 661.65 keV and 22Na 0.1 ??Ci at 511 keV. To measure the gamma rays, the graphite target converts to three different phases; solid graphite, powder graphite, and powder graphite in water solution. The later phase approximately has a doubled activity with respect to the solid graphite target up to 0.5 ??Ci of 511 keV and 1.1 ??Ci of 570 keV gamma lines were produced. This increment in activity was perhaps due to structural transformation of graphite powder to nano-particles characteristic in liquid water. 相似文献
46.
Thermal,mechanical, and corrosion resistance properties of vinyl ester/clay nanocomposites for the matrix of carbon fiber‐reinforced composites exposed to electron beam 下载免费PDF全文
Seyed Mohammad Razavi Negar Dehghanpour Seyed Javad Ahmadi Mahdi Rajabi Hamaneh 《应用聚合物科学杂志》2015,132(33)
Vinyl ester/clay nanocomposites with 1, 3, and 5% nanoclay contents were prepared. X‐ray diffractography patterns and Scanning Electron micrographs showed that nanocomposites with the exfoliated structure were formed. Thermogravimetric analysis, water absorption test, and Tafel polarization method, respectively, revealed the improvements in thermal resistance, water barrier properties, and corrosion resistance properties of the samples with an increase in the amount of the incorporated nanoclay. Tensile tests showed that nanoclay also enhanced the mechanical properties of the polymer, so that the tensile strength of the samples with 5% nanoclay was more than 3 times higher than tensile strength of pure vinyl ester samples. Overall, the best properties were observed for the samples containing 5% nanoclay. Pure vinyl ester and nanocomposite with 5% nanoclay content were exposed to the electron beam radiation and their mechanical properties improved up to 500 kGy irradiation dose. Finally, pure vinyl ester and vinyl ester/nanoclay (5%) matrixes were reinforced with carbon fiber and the effect of electron beam irradiation on their mechanical properties was examined. The tensile strength and the modulus of the samples initially increased after exposure to the radiation doses up to 500 kGy and then a decrease was observed as the irradiation dose rose to 1000 kGy. Moreover, nanoclay moderated the effect of the irradiation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42393. 相似文献
47.
Supertough (Polyamide 6)/(acrylonitrile butadiene rubber) nano alloy through in situ polymerization of caprolactam in the presence of acrylonitrile butadiene rubber nanophase 下载免费PDF全文
Shervin Ahmadi Yousef Jahani Ghasem Naderi Amir Hossein Asadollahzadeh 《乙烯基与添加剂工艺杂志》2015,21(2):116-121
In this work, polymerization of caprolactam (CL) was carried out in the presence of acrylonitrile butadiene rubber (NBR) during the reactive melt‐mixing process. During shear mixing, NBR particles swelled and dissolved in the molten CL, which led to separation and distribution of rubber particles to nanoscale in the dissolution stage. Then, in an internal mixer, supertough Polyamide 6 was prepared via melt polymerization of CL/NBR mixture, sodium caprolactam as a catalyst, and hexamethylene diisocyanate as an activator. The effects of various concentrations of catalyst and activator on the initiation time of the reaction were determined. Physical and mechanical properties of different formulations prepared via reactive melt blending were determined by tensile and impact measurements, differential scanning calorimetry, Fourier‐transform infrared spectroscopy, X‐ray scattering techniques, transmission electron microscopy, and dynamic mechanical thermal analysis. Experimental results showed that a recipe with 3% nitrile rubber in a CL/NBR mixture enhances the physical and mechanical properties the best, compared with other formulations. This condition led to the formation of NBR nanospheres during melt polymerization of Polyamide 6 as well. J. VINYL ADDIT. TECHNOL., 21:116–121, 2015. © 2014 Society of Plastics Engineers 相似文献
48.
Saharnaz Ahmadi Maryam Farokhi Parisa Padidar Mojtaba Falahati 《International journal of molecular sciences》2015,16(8):17289-17302
In this study the effect of surface modification of mesoporous silica nanoparticles (MSNs) on its adsorption capacities and protein stability after immobilization of beta-lactoglobulin B (BLG-B) was investigated. For this purpose, non-functionalized (KIT-6) and aminopropyl-functionalized cubic Ia3d mesoporous silica ([n-PrNH2-KIT-6]) nanoparticles were used as nanoporous supports. Aminopropyl-functionalized mesoporous nanoparticles exhibited more potential candidates for BLG-B adsorption and minimum BLG leaching than non-functionalized nanoparticles. It was observed that the amount of adsorbed BLG is dependent on the initial BLG concentration for both KIT-6 and [n-PrNH2-KIT-6] mesoporous nanoparticles. Also larger amounts of BLG-B on KIT-6 was immobilized upon raising the temperature of the medium from 4 to 55 °C while such increase was undetectable in the case of immobilization of BLG-B on the [n-PrNH2-KIT-6]. At temperatures above 55 °C the amounts of adsorbed BLG on both studied nanomaterials decreased significantly. By Differential scanning calorimetry or DSC analysis the heterogeneity of the protein solution and increase in Tm may indicate that immobilization of BLG-B onto the modified KIT-6 results in higher thermal stability compared to unmodified one. The obtained results provide several crucial factors in determining the mechanism(s) of protein adsorption and stability on the nanostructured solid supports and the development of engineered nano-biomaterials for controlled drug-delivery systems and biomimetic interfaces for the immobilization of living cells. 相似文献
49.
50.
Sima Balaghi Mohammad Amin Mohammadifar Azizollaah Zargaraan Hassan Ahmadi Gavlighi Mehrdad Mohammadi 《Food Hydrocolloids》2011
The sugar composition and viscoelastic behaviour of Iranian gum tragacanth exuded by six species of Astragalus was investigated at a concentration of 1.3% and varying ionic strength using a controlled shear-rate rheometer. Compositional analysis of the six species of gum tragacanth by high-performance anion-exchange chromatography with pulsed amperometric detection suggested the occurrence of arabinose, xylose, glucose, galactose, fucose, rhamnose and galacturonic acid residues in the gum structure; however, the proportions of each sugar varied significantly among the gums from the different species of Astragalus, and this variation led to interesting differences in functional properties. Rheological measurements performed on dispersions of the six species of gum tragacanth demonstrated viscoelastic properties. The mechanical spectra derived from strain sweep and frequency sweep measurements indicated that the different gum tragacanth dispersions had distinctive viscoelastic behaviours. Investigation of the viscoelastic properties of the different gum dispersions in the presence of NaCl revealed that the addition of NaCl could lead to slight to drastic decreases in the G′, G″ or η∗ values of the various gums. In general, the results indicated that the six varieties of gum tragacanth studied exhibited significantly different rheological properties; therefore, these different gums may find use in a variety of applications as stabilisers, thickeners, emulsifiers and suspending agents depending on their rheological behaviour. 相似文献