Micro and Nanosystems - Volume 10, Issue 1, 2018

Background: All modern transceiver circuits utilize high-performance band pass filters for proper frequency selection led the researchers to inaugurate the journey of CMOS active inductor. The prime performance requirements of such circuits are very low power dissipation, relatively higher Qfactor with fixed center frequency tuning but a tradeoff among these parameters is inevitable. Method: A number of active inductor-based band pass filters have been designed over the years to obtain better performance trade-offs and a discussion on these designs is presented from their advantages, disadvantages and application point of view. The active inductors are capable of working effectively in band pass filters at very high frequencies up to 11.47 GHz and can be designed to achieve smallest chip area as low as 0.005 mm2. Besides some essential critical parameters such as high-quality factor, narrow bandwidth, central frequency tuning, low voltage operation, very small power consumption etc. are also achievable. Moreover, compared to Gm-C and Q-enhanced LC tank band pass filters, filters with active inductor show better performance in terms of low power consumption, small silicon area, high Q factor and tunability. Conclusion: This review will help the engineers in designing compact and high-performance CMOS band-pass filter circuits for various RF devices.

AFM nanoindentation is a modern technique which is used for the determination of the mechanical properties of materials and biomaterials. With regards to the nanoindentation procedure, several models of applied mechanics can be used for data processing such as the Hertz model which is used in the case of spherical indenters. The purpose of this review is to provide a complete presentation of the Hertz model theory, commonly used model in the fields of Biophysics and Biomaterials as well as in other related applications. In addition, the theory which correlates the Hertz model and the general nanoindentation equation for Young's modulus determination is presented.

Objective: In this paper, electrostatically actuated micromechanical switch for battery powered electrical system has been presented. An electrostatically actuated micromechanical switch has been designed and the electromechanical characteristics have been discussed. Methods: The switching characteristics, power loss and leakage current of the switch have been obtained for 12 V/0.2 A electrical system. In order to meet the high power rating, the designed arcless micromechanical switches have been connected in a scalable cross-tied array configuration and the switching characteristics were obtained for 144 V/3 A electrical system. Result: The arc existing parts of the micromechanical switch have been identified and the arcless switching has been discussed. The reliability of the switch has been presented based on electromechanical behavior, arcless switching and scalability. The discharging characteristics of battery have been obtained for the circuit having solid-state and micromechanical switch. Conclusion: The result shows significant improvement in the power loss, battery discharging characteristics and is promising application for battery operated electrical system.

Background: Biological synthesis of nanoparticles for various biomedical applications has gained interest in recent years due to its biocompatibility. Aim: The aim of the present study is to synthesize gold nanomaterials using plant Catharanthus roseus as an eco friendly approach. Results: The treatment of aqueous solution of chloroauric acid with root extract of C. roseus led to the rapid formation of Gold Nanoparticles (AuNPs). The color change and the Surface Plasma Resonance (SPR) confirmed the formation of AuNPs. Atomic Force Microscopy (AFM) was used to study the shape of the nanoparticles and X-Ray Diffraction (XRD) used to study the phase purity of the nanoparticles. The UV-vis spectra of the nanoparticles showed absorbance maxima peak at 538 nm. Transmission Electron Microscopy (TEM) showed spherical and triangle shaped nanoparticles with average size ranging from 30 – 60 nm as a result of plant extract concentration variation. Conclusion: The nanoparticles were found discrete with spherical and triangle shape dominant.

Background: Increased level of pollutions has led to the serious environmental problems and given a way to develop the better biodegradable polymers. Soy-based polymers have been widely developed and used for the packaging purposes, but these polymers were reported to be degraded due to the high moisture absorptivity, which leads to the spoilage of the packed food at a quicker rate. Aim: This research sheds a light on the preparation of soy-based polymer and nanocomposite having a low absorptivity by a wet method using Palmitic Acid (PA). Method: PA was added up to 30% by the weight of soy protein isolate, in addition glycerol was used as the plasticizer and 25% PA was found to be the optimum. The polymer sheets were characterized by Fourier Transform Infrared Spectroscopy, Thermal Gravimetric-DTA and Scanning Electron Microscopy analyses. In addition, the moisture content and tensile studies were monitored. For the preparation of nanocomposite, soy-based nanoparticles were synthesized by grafting. Result: The generated nanocomposite has shown the reduced moisture absorptivity and higher mechanical properties.

Background: Aromatic polyamides are important materials having outstanding thermal, electronic and mechanical properties among high performance polymers and industrial plastics. In addition, aromatic polyamides can be utilized in electronic devices with their low dielectric constant which indicates the storage capacity of these devices. Objective: Free volume is very important for dielectric materials and increase in free volume of a polymer reduces its dielectric constant. The aims of the current study are to create free volume in the bulk polyamide structure and to reduce the dielectric constant by using β-Ni(OH)2 particles. Method: The composites obtained from β-Ni(OH)2 (flower-like nanoparticles) in a naphthalene-based polyamide matrix were prepared. Firstly, β-Ni(OH)2 nanoparticles were synthesized by microwaveassisted solvothermal technique under various reaction conditions. Then, polyamide/β-Ni(OH)2 composites were prepared via direct dispersion methods at different reinforcement ratios. Results: β-Ni(OH)2 (flower-like nanoparticles) and polyamide/β-Ni(OH)2 composites were prepared successfully. Our studies showed that the dispersion of β-Ni(OH)2 nanoparticles in polyamide matrix is homogenous and prepared composites have good thermal and dielectric properties with promising results for electronic industry. Conclusion: Dielectric properties of the prepared composites decrease with increasing β-Ni(OH)2 nanoparticle content and all composites show low dielectric constant when β-Ni(OH)2 nanoparticle content is over 1 wt.% compared to the pure polyamide.

Objective: Long-term stable and highly versatile and technologically important sol-gel derived material's synthesis, characterization and some of its potential applications are presented. Methods: Multifunctional sol-gel precursor is added with 3,5-bis(trifluoromethyl)benzylamine derived peptide self assembled nanotubes (BTTPNTs), to form a core-shell, BTTPNTs@SiO2 matrix. The prepared material is characterized by UV-vis absorbance (UV-vis), Diffuse Reflectance Spectra (DRS), X-Ray Diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM), Confocal Raman Spectral and Imaging (CRS & CRM), Atomic Force Microscopy (AFM) and Transmittance Electron Microscopy (TEM). Result: The obtained results clearly revealed the expected BTTPNTs implanted core and SiO2 as shell in the formed nanocomposites. Conclusion: Cyclic Voltammetry (CV) studies explore the sensing activity and UV-vis spectroscopy presents the smart UV protective ability of the coated glass systems.

Objective: Inertial Micro Electro-Mechanical Systems (MEMS) have recently been proposed as sensing components of surface-mounted structural health monitoring systems aimed to detect damage in flexible plates, subjected to either quasi-static or dynamic loadings. Method: In this paper, we discuss a topology optimization approach to smartly deploy an array of MEMS accelerometers over thin flexible plates, partially allowing for scattering in their placement. Result: We assume damage (i.e. a reduction of the local bending stiffness of the plate) to be located anywhere, and we show how boundary conditions, symmetry conditions and the stacking sequence in case of a composite laminate can affect the optimal sensor placement.