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101.
Soraya Aghnout Gholamreza Karimi Mostafa Rahimi Azghadi 《Journal of Computational Electronics》2017,16(2):401-410
Triplet-based spike-timing-dependent plasticity (TSTDP) is an advanced synaptic plasticity rule that results in improved learning capability compared to the conventional pair-based STDP (PSTDP). The TSTDP rule can reproduce the results of many electrophysiological experiments, where the PSTDP fails. This paper proposes a novel memristive circuit that implements the TSTDP rule. The proposed circuit is designed using three voltage (flux)-driven memristors. Simulation results demonstrate that our memristive circuit induces synaptic weight changes that arise due to the timing differences among pairs and triplets of spikes. The presented memristive design is an initial step toward developing asynchronous TSTDP learning architectures using memristive devices. These architectures may facilitate the implementation of advanced large-scale neuromorphic systems with applications in real-world engineering tasks such as pattern classification. 相似文献
102.
This study investigates the cinematic representation of city crime transactions in Chicago in the 1980s. The narrative nature of cinema provides an imaginative context for interpreting the physical and nonphysical dimensions of urban crimes. From a critical interpretive position, based on Peirce's semiotics, this study uses “urban cinesemiotics” as the method to select image signs, identify their associated Chicagoan objects, and interpret their design-oriented meaning. The theoretical roots of crime prevention through environmental design constitute the basis for the interpretation of movies. A total of 27 crime-related scenes from 9 Chicagoan movies made in the 1980s illustrate that most urban settings suffer from the lack of crime-preventive environmental design. In particular, natural surveillance (eyes on the street), encounter and enclosure, and border vacuums are major environmental factors that affect urban crimes in Chicago. Some crime scenes also depict why environmental design cannot influence individuals' criminal intentions necessarily nor can they solve urban safety single-handedly. 相似文献
103.
Ali Shokouhi Gholamreza Pazuki Abdolreza Aroujalian 《Chemical Engineering Communications》2016,203(1):8-17
This work focuses on modeling of the sorption step as a main step in the mass transport through the pervaporation process. For this purpose, four thermodynamic models including Flory–Huggins (FH), Universal Quasichemical (UNIQUAC), modified Non-Random Two-Liquid (M-NRTL), and modified Wilson (M-Wilson) were used to predict the equilibrium sorption of ethanol/water mixtures into the polydimethylsiloxane (PDMS) membrane. In the M-Wilson model, the reference state based on pure enthalpy of components was used to determine the residual term. Moreover, the influences of ethanol feed content and temperature on the liquid sorption level and sorption selectivity were studied experimentally and theoretically. The results indicated that the proposed models were successfully able to determine the sorption level of the ethanol aqueous solutions into the PDMS membrane. Moreover, the M-NRTL and M-Wilson models were found to be much more accurate than the FH and UNIQUAC models to determine the volume fraction of the penetrants in the PDMS membrane. It was also observed that the total and ethanol sorptions increased with an enhancement in the ethanol feed concentration, while the membrane sorption selectivity decreased. Moreover, increasing the operating temperature led to higher sorption of both ethanol and water, whereas the sorption selectivity did not show significant changes with temperature. 相似文献
104.
This paper investigates the wind energy potential over 42 sites in Iran. Ten years of wind data (1996–2005) were used from weather stations located at these sites. Different criteria were considered, including vertical wind profile, wind power density (WPD), wind frequency distribution, wind sustainability, seasonal variation, turbulence intensity and peak demand matching. Air density and roughness length, which play important role in the calculation of the WPD potential, were derived for each station site. Simple scoring was used to rank the mostly windy sites. It is concluded that Sistan and Bluchistan governorate (Zabol) has the highest potential. Zahedan, Jazireh Kish and Ardebil also have high wind power potential. 相似文献
105.
Analysis of Novel Approach to Design of Ultra‐wide Stopband Microstrip Low‐Pass Filter Using Modified U‐Shaped Resonator
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A novel microstrip low‐pass filter is presented to achieve an ultra‐wide stopband with 11 harmonic suppression and very sharp skirt characteristics. The filter is composed of a modified U‐shaped resonator (which creates two fully adjustable transmission zeroes), a T‐shaped resonator (which determines a cut‐off frequency), and four radial stubs (which provide a wider stopband). The operating mechanism of the filter is investigated based on a proposed equivalent‐circuit model, and the role of each section of the proposed filter in creating null points is theoretically discussed in detail. The presented filter with 3 dB cut‐off frequency has been fabricated and measured. Results show that a relative stopband bandwidth of 164% (referred to as a 22 dB suppression) is obtained while achieving a high figure‐of‐merit of 15,221. 相似文献
106.
107.
The removal of cationic dyes from aqueous solutions by adsorption onto pistachio hull waste 总被引:1,自引:0,他引:1
The efficacy of pistachio hull powder (PHP) prepared from agricultural waste was investigated in this study as a novel adsorbent for the elimination of dye molecules from contaminated streams. Removal of methylene blue (MB) as a cationic model dye by PHP from aqueous solution was studied under different experimental conditions. The selected parameters were solution pH (2–10), PHP dosage (0.5–3 g/L), MB concentrations (100–400 mg/L), contact time (1–70), and solution temperature (20–50 °C). The experimental results indicated that the maximum MB removal could be attained at a solution pH of 8. The dosage of PHP was also found to be an important variable influencing the MB removal percentage. The removal efficiency of MB improved from 94.6 to 99.7% at 70 min contact time when the MB concentration was decreased from 300 to 100 mg/L at a pH and PHP dosage of 8 and 1.5 g/L, respectively. The kinetic analysis showed that the pseudo-second-order model had the best fit to the experimental data. The Langmuir equation provided the best fit for the experimental data of the equilibrium adsorption of MB onto PHP at different temperatures. In addition, the maximum adsorption capacity increased from 389 to 602 mg/g when the temperature was increased from 20 to 50 °C. The thermodynamic evaluation of MB adsorption on PHP revealed that the adsorption phenomenon under the selected conditions was a spontaneous physical process. Accordingly, pistachio hull waste was shown to be a very efficient and low-cost adsorbent, and a promising alternative for eliminating dyes from industrial wastewaters. 相似文献
108.
Carboxymethyl cellulose (CMC) composite films were prepared from CMC solutions (2% w/v) containing multiwalled carbon nanotubes (MWCNT) as nanofiller and glycerol (25% w/w CMC) as plasticizer. Tensile strength, elongation at break (EAB), young's modulus, water solubility, water swelling, water uptake, and water vapor permeability (WVP) for CMC films were 27.5 ± 2.5 MPa, 11.2 ± 0.8%, 198 ± 18 MPa, 57 ± 1.5%, 738 ± 25%, 124 ± 4%, and 0.55 ± 0.036 g.mm/m2.kPa.h, respectively. By increasing the relative humidity from 11.4 to 85.5%, the moisture absorption (MA) of CMC films was increased from 4 to 38%. Incorporation of MWCNT into the matrix caused a significant increase in the tensile strength, decrease in EAB, increase in young's modulus, decrease in water solubility, decrease in water swelling, decrease in water uptake, and decrease in MA. CMC/MWCNT films containing 1% MWCNT showed the lowest WVP. Scanning electron microscopy showed a good dispersion of MWCNT in the CMC matrix. CMC/MWCNT films containing >1% MWCNT showed significant antibacterial activities against both Gram‐positive and Gram‐negative bacteria in a dose‐dependent manner. Thus, good mechanical properties and water resistance along with strong antibacterial activities make CMC films grafted with MWCNT as a suitable packaging material. POLYM. COMPOS., 36:145–152, 2015. © 2014 Society of Plastics Engineers 相似文献
109.
In this work, we grow composite structures consisting of magnetic and non-magnetic metal or alloy nanowires electrodeposited into the ion etched tracks previously created inside Si substrates. The holes are then filled by Co–Pt alloys and Co/Pt multilayers using electrodeposition technique making a large number of parallel nanowires. This process takes place in a single electrolyte containing Co+2 and Pt+4 ions by applying a proper deposition potential using a computer control potentiostat. The magnetic properties of the sample were studied using vibrating sample magnetometer. Magnetoresistive behaviour of the nanowire samples was then studied by subjecting the samples to an external magnetic field. The results show that the Co/Pt multilayered nanowires exhibit a large magnetoresistance, while the Co–Pt alloys only show anisotropic magnetoresistance. This result could be of a great interest for the sensor fabrication community as they will provide a view on a very important direction of the development of the wide spread sensor industry, and more importantly for understanding the physical phenomena underlying the magnetic/non-magnetic nanostructures. 相似文献
110.
Zohre Pourgholamhossein Gholamreza Askari Fattah Talaei Hamid Mirmohammad Sadeghi 《International Journal of Circuit Theory and Applications》2020,48(12):2078-2096
This paper presents high power, thermal analyses, and implementation of a stepped impedance high-power low-pass filter (LPF). A comprehensive model and analysis have been developed for the design and simulation of the LPF. In this analysis, power handling capacity and breakdown-voltage are discussed, and the effects of critical points are considered. The attenuation due to conductor and dielectric losses is also studied. The novelty of our approach lies in employing theoretical analysis to estimate the power-dissipation of the filter based on the proposed equivalent circuit. An accurate method is also introduced to calculate attenuation in the filter's elements. Thermal analysis to obtain accurate temperature profiles is done for the first time based on the electro-thermal simulation. Consequently, an effective cooling method is used to spread heat across the entire filter. Finally, the filter was implemented and tested to operate at L-band with handling 8 kW peak and 800 W average power. The insertion-loss is less than 0.27 dB, the stop-band attenuation is more than 60 dB, and the return-loss is better than 15.7 dB. The filter is capable of tolerating produced heat without any destructive effects at a maximum temperature of about 200°C above ambient. The theoretical analysis and experimental results show that the LPF is suitable for high-power microwave applications. 相似文献