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161.
Jahan Bakhsh RaoofAuthor Vitae Reza OjaniAuthor VitaeSeyed Mahdi GolabiAuthor Vitae Ezat Hamidi-AslAuthor VitaeMohammad Saeid HejaziAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):195-201
Development of an electrochemical biosensor based on peptide nucleic acid (PNA) probe for detection of target DNA sequence and single nucleotide mutation in p53 tumor suppressor gene corresponding oligonucleotide using methylene blue (MB) as an electrochemical indicator is described. The interaction between MB and short sequence of p53, one of the most important tumor suppressor genes due to its dysfunction in the majority of human cancers, was studied by differential pulse voltammety (DPV). Probe modified electrode was prepared by self-assembled monolayer (SAM) formation of thiolated PNA molecules on the surface of gold electrode (GE). The hybridization of PNA probe with target DNA was performed in solution to form PNA-DNA hybrid on the surface of the GE. A significant increase in the reduction signal of MB was observed upon hybridization of the probe with the complementary DNA. The selectivity of the biosensor was studied using noncomplementary oligonucleotides. Furthermore, our results confirmed the ability of the sensor to detect single base mismatch in the sample oligonucleotide. The influence of probe concentration on the effective discrimination against noncomplementary sequence and point mutation was also investigated. Diagnostic performance of the biosensor is described and the detection limit is found 6.82 × 10−10 M. The electrochemical impedance spectroscopy was also employed to further investigate the sensor function. 相似文献
162.
Hamed Mobki Morteza H. Sadeghi Saeid Afrang Ghader Rezazadeh 《Microsystem Technologies》2011,17(9):1447-1452
In this work a novel MEMS based variable capacitor has been presented. To increase the tunability and decrease the applied
voltage, the conventional fixed-fixed beam used in CPW lines has been changed to a fixed-simple supported beam. The proposed
structure is a simple cantilever micro-beam in the first step of deflection and is changed to a fixed-simple supported micro-beam
in the second step of motion. In the capacitive micro-structures increasing the applied voltage decreases the equivalent stiffness
of the structure and leads the system to an unstable condition by undergoing to a saddle node bifurcation. In the proposed
structure to avoid pull-in instability and increase the capacitance tuning range, mechanical stiffness of the structure is
increased by changing boundary conditions by locating a pedestal in the end of the cantilever beam. The governing nonlinear
equation for static deflection of the micro-beam, based on Euler–Bernoulli micro-beam theory has been presented. The results
show that the proposed structure increases the capacitance tuning range and decreases the applied voltage. The results also
show that the position of the pedestal affects the tunability and the threshold voltage of the structure. 相似文献
163.
Reza Davarnejad Meysam Sabzehei Fatemeh Parvizi Saeid Heidari Asma Rashidi 《化学工程与技术》2019,42(12):2717-2725
Due to its low viscosity, soybean oil is commonly used as edible oil. Its production is accompanied by a large amount of wastewater containing hazardous materials like phenolic compounds. In this study, the electro‐Fenton process with response surface methodology was applied for oil removal from wastewater of soybean oil plants. Five independent variables, including reaction time, pH, current density, molar ratio of H2O2 to Fe2+, and volume fraction of H2O2 to wastewater, were investigated for their effects on oil removal. The significant independent variables were optimized by the Box‐Behnken design. The optimum conditions were statistically obtained, and the results were confirmed by experiment. 92.66 % oil removal were experimentally found for the optimum conditions. 相似文献
164.
Huge energy consumption in cloud infrastructure has turned into a challenging problem. Virtualization technology, which can be regarded as the first step in energy conservation by offering benefits like on-demand resource provisioning and live migration, creates a platform on which different resource allocation and scheduling policies can be defined on how to accumulate VMs on fewer number of hosts while respecting performance metrics. In this paper, after presenting a classification on VM placement strategies, we propose different combinatorial placement policies that take load dispersion of hosts into account to dynamically adapt their placement decisions. Simulated experiments through Cloudsim showed noteworthy results concerning energy-performance tradeoff. 相似文献
165.
Yazici Adnan Koyuncu Murat Yilmaz Turgay Sattari Saeid Sert Mustafa Gulen Elvan 《Multimedia Tools and Applications》2018,77(2):2225-2260
Multimedia Tools and Applications - This paper introduces an intelligent multimedia information system, which exploits machine learning and database technologies. The system extracts semantic... 相似文献
166.
Shendy Saeid Ahmadizadeh Shahverdizadeh Gholam Hossein Babazadeh Mirzaagha Hosseinzadeh-Khanmiri Rahim Es′haghi Moosa 《SILICON》2020,12(7):1735-1742
Silicon - Magnetic materials grafted with acetic acid (Fe3O4@SiO2COOH MNPs) were successfully prepared from the incorporation of bromoacetic acid as a functional group on the surface of magnetite... 相似文献
167.
168.
In this work, we have modeled silicon quantum dot (QD)-based single-electron transistors (SETs) operating at room temperature and investigated the effect of the QD’s energy-level broadening on the performance of the SET. First we obtained the energy levels and corresponding wave functions for spherical Si QDs by solving the coupled Schrödinger–Poisson equations in three dimensions. Then, we demonstrated different tunneling current rates for separated energy levels by considering nonequal energy-level broadenings. Accordingly, an expression for the corresponding tunneling rates in the quantum Coulomb blockade regime was derived. In the next step, the transconductance characteristics of the Si QD SET device with Coulomb oscillations were simulated, and their differences from previously investigated metal-based SETs were demonstrated. Finally, by applying different bias voltages, we determined the effect of temperature variations on the transconductance characteristics. 相似文献
169.
According to recent earthquake experiences and experimental results, the local buckling is the most important parameter for limiting the ductility of short braces and prevents earthquake energy absorption in larger drifts. A new theory is introduced to prevent harmful effects of local buckling and use it as an energy absorption device in braced frames. According to this theory oblique stiffeners are provided inside braces section and it is expected to divide lateral drift of the system to smaller deflections inside stiffeners intervals. As much as number of local buckling along braces increases, more energy will be absorbed and the fracture life of the sections increases considerably. This theory is supported by half-scale experimental results and numerical modeling. The obtained results represent uniform and stable energy absorption and reasonable system ductility. 相似文献
170.
Mir Majid Teymoori Massoud Dousti Saeid Afrang 《International Journal of Circuit Theory and Applications》2020,48(12):2111-2129
A phase shifter is one of the main components of radars and phased array systems. In this paper, a novel three-state two-bridge unit cell is presented for a compact low-loss six-bit distributed microelectromechanical systems (MEMS) transmission line (DMTL) phase shifter. The proposed unit cell includes a coplanar waveguide (CPW) transmission line, a MEMS bridge on the signal line, two metal-air-metal (MAM) capacitors on a glass substrate, and two additional electrodes under the MEMS bridge, near the signal line. Using these electrodes, it is possible to generate two different phase states employing the MEMS bridge, and the third state is produced by a metal-air-metal (MAM) bridge. Hence, the designed structure can generate three different phase shifts per unit cell (i.e., 5.625°, 11.25°, and 22.5° phase shifts). The novelty of this design is that the number of unit cells is considerably reduced from 64 in a conventional six-bit phase shifter to only 17 in our design. Therefore, the total length of the six-bit phase shifter and average loss are considerably reduced. The designed structure is calculated and simulated at 32 GHz using MATLAB and ANSOFT HFSS, respectively. According to the calculation and simulation results, the lateral size of the phase shifter is only 8.5 mm, the root mean square (RMS) phase error is 1.38°, and the average loss is 1.1 dB. The feasibility of the proposed design is investigated using the proposed fabrication process. The designed phase shifter can be easily scaled to other frequencies for radar and satellite applications with more bits. 相似文献