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We have started a new research project on a hybrid power generation system consisting of piezoelectric, thermoelectric and solar cell modules. In the first step, we have focused on the antireflection coating based on zinc oxide (ZnO) and metal nanolayers incorporated in solar cells. In layered structure containing ZnO and metal nanoscale layers, we have presented the possibility of increasing wave transmission in the visible region by adding the top and bottom cap layers. The enhancement of optical transmission is very important in improving the performance of sensor protections, solar cells, UV protective films and transparent conductive display panels electrode. It is found that, the structure containing both the top and bottom cap layers (S3) yields larger transmittance than the structures S1 without any cap or S2 just with one cap layer. The maximum transmittance in the visible range can be increased from 33% to 67%. In addition, for the TE mode (TM mode), the maximum value of transmission in the S1 and S2 structures occurs at angles close to normal incidence while in the S3 multilayer it happens around 1 radian, that is, the behavior of the TE mode is the opposite of the TM mode. Also, when the incident angle varies, the band edges experience a blue shift. The amount of TE shift is more pronounced than TM one. Moreover, the metal with higher plasma frequency will move the band gap edges to the higher frequencies.

The aim of this study is to enhance hydrogen energy share in a RCCI engine. The engine under consideration is fueled with diesel oil and natural gas enriched with hydrogen or syngas and is set to operate at 9.4 bar gross indicated mean effective pressure (Mid- Load). The syngas used in this study consists of hydrogen and carbon monoxide which are mixed together on a volumetric ratio of 80:20. A fixed amount of diesel oil is injected per cycle into the combustion chamber of the RCCI engine. Based on two different strategies, hydrogen or syngas mixed with exhaust gas recirculation are admitted gradually along with natural gas while ensuring that always the low temperature combustion concept is fulfilled. The RCCI engine operation is simulated through commercial software coupled with chemical kinetics solver. The simulation results show that without any engine diesel knock occurrence, by adding hydrogen to natural gas, the share of hydrogen energy could be increased up to 40.43% while the engine power output is reduced only by about 1%. Also, syngas addition to natural gas causes that the share of hydrogen energy could be increased up to 27.05% while improves the engine power more than 4%. At the same time, by considering two mentioned strategies, the overall hydrocarbon fuel consumption per cycle can be reduced by up to 46.60% and 33.86%, respectively. Moreover, having the gross indicated efficiency of well over 50% and significant reduction in the engine emissions compared to RCCI combustion fueled solely with natural gas and diesel oil are achievable.

By employing the transfer matrix method, we report the terahertz spectral properties of graphene induced photonic band gap in four types of common one-dimensional quasiperiodic structures based on double-period, Fibonacci, Thue-Morse and Cantor sequences with approximately the same number of layers. In this paper, a graphene monolayer is sandwiched between two adjacent dielectric slabs. It is found that due to the presence of graphene in each structure, an additional gap (GPBG) is emerged. The upper band edge of GPBG moves to the higher frequencies and gets enlarged, as the chemical potential and incident angle increase. The biggest and the smallest bandwidths belong to the Cantor and double-period sequences. Also, the height of the absorption peak at the GPBG edge goes up as the temperature, graphene thickness and damping factor increase. Moreover, the highest and lowest field localizations exist in the Cantor and Fibonacci structures, respectively. Some other features are presented in the results section.

In this paper, by considering wave phase analysis, the density of modes, group velocity, and lateral shift in one-dimensional multilayer are theoretically computed by using the transfer matrix method in the terahertz domain. The proposed structure is based on the Fibonacci sequence constituted of uniaxial indefinite medium and

In the terahertz frequency domain, we theoretically attempt to determine some properties of kerr-type nonlinear response of a graphene-coated one-dimensional quasiperiodic structure based on Fibonacci sequence. The supposed structure is constituted by silicon dioxide and nonlinear polystyrene dielectrics where graphene sheets are located between them. The calculations are accomplished by using standard transfer matrix method. Our numerical results demonstrate that the introduction of graphene sheets in the structure has an important role in reducing bistability thresholds. It is found that for both TE and TM waves the switching-up and switching-down thresholds of bistability are reduced in comparison to without graphene case. In addition, the threshold values of TM mode are less than those of TE one. Also, by manipulating parameters such as graphene chemical potential, graphene damping constant and sequence number of structure, some other interesting features are achieved. This paper provides a way to reduce bistability thresholds which are of optical switching issues.

The present paper attempts to determine the properties of photonic spectra of Thue-Morse, double-period and Rudin-Shapiro one-dimensional quasiperiodic multilayers. The supposed structures are constituted by high temperature HgBa2Ca2Cu3O10 and YBa2Cu3O7 superconductors. Our investigation is restricted to the visible wavelength domain. The results are demonstrated by the calculation of transmittance using transfer matrix method together with Gorter-Casimir two-fluid model. It is found that by manipulating the parameters such as incident angle, polarization, the thickness of each layer and operation temperature of superconductors the transmission spectra exhibit some interesting features. This paper, provides us a pathway to design tunable total reflector, optical filters and optical switching based on superconductor quasiregular photonic crystals.

In the ultraviolet region and by using transfer matrix method, the transmission spectra of electromagnetic waves through one-dimensional quasiperiodic photonic structures consisting of high-temperature yttrium barium copper oxide (Y123) superconductor and strontium titanate (STO) dielectric layers are studied theoretically. It is shown that for TE polarization at oblique incidence two band gaps are created, while for TM polarization three band gaps are produced. The edges of both polarizations shift to higher wavelengths by increasing incident angles. Also, for angles of incidence greater than 78∘, the second gap for TM-polarized light is eliminated. It is also found that in the supposed structure the number of PBGs can be modulated by the thickness of dielectric layer, while it is nearly insensitive to the thickness of superconductor layer. Interestingly, for the incidence angles other than normal incidence the structure can exhibit some narrow resonant peaks near wavelengths where the electric permittivity of the superconductor layer changes sign. These resonant peaks are only for TM polarization and not present for TE polarization. This structure can act as a very compact polarization sensitive splitters and defect-free multichannel narrowband tunable filters.

The purpose of this paper is to theoretically investigate the properties of electromagnetic wave propagating in both one-dimensional periodic and quasiperiodic photonic crystals consisting of high-temperature yttrium barium copper oxide and strontium titanate dielectric nano-scale materials. By using the transfer matrix method, angle-, polarization- and thickness-dependences of created PBGs are explored individually for periodic and quasiperiodic structures, and some interesting features are presented in the results section. Such supposed structures can be used as very compact polarization sensitive splitters and defect-free multichannel narrowband tunable filters.

In this paper, we report the analysis of the electromagnetic wave transmission having a wave length near infrared propagating in Fibonacci quasiperiodic multilayer structures made of fullerene and germanium materials. We observe that within the stop band the reflection phase difference changes smoothly and increases with the increasing of the incident angle. In the center of the gap the reflection phase difference remains almost unchanged in a broad wavelength band. Especially, at both the edges of the gap the reflection phase difference keeps zero in spite of the change of incident angle. Basing on our results, the supposed structure provides a convenient way to design very compact phase controllers such as phase retarders.

The band characteristics and the phase shift of electromagnetic waves in one-dimensional Fibonacci photonic structures composed of nano-scale fullerene and semiconductor layers are investigated theoretically in detail for both TE and TM polarizations and for different incident angles. We adopt the transmission matrix method to analyze the transmission properties of supposed sub-wavelength structure. We observe that within the stop band, the reflection phase difference changes smoothly and increases with the increasing of the incident angle. Furthermore, the phase shift decreases with the incident angle increasing for TE mode, and increases with the incident angle increasing for TM mode. Especially, at both the edges of the gap, the reflection phase difference keeps zero in spite of the change of incident angle. Based on our results, the supposed structure provides a convenient way to design very compact phase controllers such as phase retarders.

Background Pseudomonas aeruginosa is one of the most common Gram-negative pathogen causing nosocomial infection worldwide. The emergence of multi-drug resistant strains has become a major clinical concern in recent years. Resistance-nodulation-cell division (RND) family efflux pumps play an important role in the development of multidrug resistance in P. aeruginosa. Objectives The aims of the present study were to evaluate the antimicrobial susceptibility against carbapenems used and to evaluate the gene expression of two resistance nodulation cell division-type efflux pump systems (MexB and MexY) among carbapenem non-susceptible P. aeruginosa. Methods A total of 256 non-repetitive P. aeruginosa were collected from the different clinical samples of patients admitted in Qazvin and Tehran educational hospitals. Antimicrobial susceptibility testing was performed by standard Kirby-Bauer method. The expression of MexB and MexY genes was assessed by quantitative real-time polymerase chain reaction (qRT-PCR). Results In total, 107 (41.8%) isolates were non-susceptible to imipenem and/or meropenem. All carbapenem non-susceptible isolates were positive for the presence of MexB and MexY genes. The expression of MexB (P value = 0.004) and MexY (P value = 0.001) genes was significantly increased, compared to standard carbapenem sensitive strains. Conclusions The findings of the present study showed the considerable presence of carbapenem resistance among the clinical isolates of P. aeruginosa. The overexpression of MexB and MexY genes is also established among these resistant isolates collected from studied hospitals in Iran.

In this paper, by using the theoretical model based on the transfer matrix method, we theoretically study the optical properties of electromagnetic waves in one-dimensional hybrid periodic/quasiregular heterostructures containing nano-scale fullerene and semiconductor layers. The results show that a hybrid configuration is a promising candidate for resonant cavities with strong mode localization. A future application of these structures can be realized in the field of random lasers where the quasiregular structures, acting like defects in the hybrid systems, could serve as a new type of complex cavity that provides the feedback for laser action.