MXene based nanomaterial is an uprising two-dimensional material gaining tremendous scientific attentions due to its versatile properties for the applications in electronic devices, power generation, sensors, drug delivery, and biomedicine. However, the cytotoxic effects of MXene still remained a huge concern. Therefore, stringent analysis of biocompatibility of MXene is an essential requirement before introduction to human physiological system. Several in vitro and in vivo toxicological studies have been reported to investigate the interactions between MXenes with living organisms such as microbes, mammalian cells and animal models. The biological response and cytotoxicity reported were dependent on the physicochemical properties of MXene. The biocompatibility and cytotoxicity of MXene were dependent on size, dose, and surface coating. This review demystifies the in vitro and in vivo biocompatibility studies associated with MXene. Various methods proposed to mitigate the cytotoxicity of MXene for in vivo applications were revealed. The machine learning methods were developed to predict the cytotoxicity of experimentally synthesized MXene compounds. Finally, we also discussed the current research gaps of applying MXenes in biomedical interventions.
A low-power wideband mixer is designed and implemented in 0.13 µm standard CMOS technology based on resistive feedback current-reuse (RFCR) configuration for the application of cognitive radio receiver. The proposed RFCR architecture incorporates an inductive peaking technique to compensate for gain roll-off at high frequency while enhancing the bandwidth. A complementary current-reuse technique is used between transconductance and IF stages to boost the conversion gain without additional power consumption by reusing the DC bias current of the LO stage. This downconversion double-balanced mixer exhibits a high and flat conversion gain (CG) of 14.9 ± 1.4 dB and a noise figure (NF) better than 12.8 dB. The maximum input 1-dB compression point (P1dB) and maximum input third-order intercept point (IIP3) are -13.6 dBm and -4.5 dBm, respectively, over the desired frequency ranging from 50 MHz to 10 GHz. The proposed circuit operates down to a supply headroom of 1 V with a low-power consumption of 3.5 mW.
Micro-electro mechanical system (MEMS) based oscillators are revolutionizing the timing industry as a cost effective solution, enhanced with more features, superior performance and better reliability. The design of a sustaining amplifier was triggered primarily to replenish MEMS resonator's high motion losses due to the possibility of their 'system-on-chip' integrated circuit solution. The design of a sustaining amplifier observing high gain and adequate phase shift for an electrostatic clamp-clamp (C-C) beam MEMS resonator, involves the use of an 180nm CMOS process with an unloaded Q of 1000 in realizing a fixed frequency oscillator. A net 122dBΩ transimpedance gain with adequate phase shift has ensured 17.22MHz resonant frequency oscillation with a layout area consumption of 0.121 mm2 in the integrated chip solution, the sustaining amplifier draws 6.3mW with a respective phase noise of -84dBc/Hz at 1kHz offset is achieved within a noise floor of -103dBC/Hz. In this work, a comparison is drawn among similar design studies on the basis of a defined figure of merit (FOM). A low phase noise of 1kHz, high figure of merit and the smaller size of the chip has accredited to the design's applicability towards in the implementation of a clock generative integrated circuit. In addition to that, this complete silicon based MEMS oscillator in a monolithic solution has offered a cost effective solution for industrial or biomedical electronic applications.
Density functional theory computational investigation was performed to study the electronic structures, muon sites, and the associated hyperfine interactions in [Au25(SR)18]0 and [Au25(SeR)18]0 where R is phenylethane. The calculated electronic structures show inhomogeneous spin density distribution and are also affected by different ligands. The two most stable muon sites near Au atoms in the thiolated system are MAu11 and MAu6. When the thiolate ligands were replaced by selenolate ligands, the lowest energy positions of muons moved to MAu6 and MAu5. Muons prefer to stop inside the Au12 icosahedral shell, away from the central Au and the staple motifs region. Muonium states at phenyl ring and S/Se atoms in the ligand were found to be stable and the Fermi contact fields are much larger as compared to the field experienced by muons near Au atoms.
In this paper, a defected ground-structured antenna with a stub-slot configuration is proposed for future 5G wireless applications. A simple stub-slot configuration is used in the patch antenna to get the dual band frequency response in the 5G mid-band and the upper unlicensed frequency region. Further, a 2-D double period Electronic band gap (EBG) structure has been implemented as a defect in the metallic ground plane to get a wider impedance bandwidth. The size of the slots and their positions are optimized to get a considerably high impedance bandwidth of 12.49% and 4.49% at a passband frequency of 3.532 GHz and 6.835 GHz, respectively. The simulated and measured realized gain and reflection coefficients are in good agreement for both operating bandwidths. The overall antenna structure size is 33.5 mm × 33.5 mm. The antenna is fabricated and compared with experimental results. The proposed antenna shows a stable radiation pattern and high realized gain with wide impedance bandwidth using the EBG structure, which are necessary for the requirements of IoT applications offered by 5G technology.
In the current research work, a facile synthesis of a series of novel thiophene-based derivatives of 5-bromothiophene-2-carboxylic acid ( 1 ) have been synthesized. All analogs ( 5a - 5e , 10a - 10f ) were obtained from the coupling reaction of 5-bromothiophene-2-carboxylic acid ( 1 ) and different arylboronic acids with moderate-to-good yields under controlled and optimal conditions. The structures of the newly synthesized compounds were characterized through spectral analysis and their spasmolytic activity, and most of the compounds exhibited potentially good spasmolytic effect. Among the synthesized analogs, compound phenethyl 5-(3,4-dichlorophenyl)thiophene-2-carboxylate ( 10d ) particular showed an excellent spasmolytic effect with an EC 50 value of 1.26. All of the compounds were also studied for their structural and electronic properties by density functional theory (DFT) calculations. Through detailed insight into frontier molecular orbitals of the compounds and their different reactivity descriptors, it was found that the compounds 10c and 5c are the most reactive, while 10a is the most stable in the series. Furthermore, compounds 10c and 5c showed a very good NLO response with the highest β values.
Online voting is a trend that is gaining momentum in modern society. It has great potential to decrease organizational costs and increase voter turnout. It eliminates the need to print ballot papers or open polling stations-voters can vote from wherever there is an Internet connection. Despite these benefits, online voting solutions are viewed with a great deal of caution because they introduce new threats. A single vulnerability can lead to large-scale manipulations of votes. Electronic voting systems must be legitimate, accurate, safe, and convenient when used for elections. Nonetheless, adoption may be limited by potential problems associated with electronic voting systems. Blockchain technology came into the ground to overcome these issues and offers decentralized nodes for electronic voting and is used to produce electronic voting systems mainly because of their end-to-end verification advantages. This technology is a beautiful replacement for traditional electronic voting solutions with distributed, non-repudiation, and security protection characteristics. The following article gives an overview of electronic voting systems based on blockchain technology. The main goal of this analysis was to examine the current status of blockchain-based voting research and online voting systems and any related difficulties to predict future developments. This study provides a conceptual description of the intended blockchain-based electronic voting application and an introduction to the fundamental structure and characteristics of the blockchain in connection to electronic voting. As a consequence of this study, it was discovered that blockchain systems may help solve some of the issues that now plague election systems. On the other hand, the most often mentioned issues in blockchain applications are privacy protection and transaction speed. For a sustainable blockchain-based electronic voting system, the security of remote participation must be viable, and for scalability, transaction speed must be addressed. Due to these concerns, it was determined that the existing frameworks need to be improved to be utilized in voting systems.
We report on measurements of differential cross sections (DCSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol (THFA). The energy range of these experiments was 20-50 eV, while the scattered electron was detected in the 10°-90° angular range. There are currently no other experimental data or theoretical computations against which we can directly compare the present measured results. Nonetheless, we are able to compare our THFA DCSs with earlier cross section measurements for Rydberg-state electronic excitation for tetrahydrofuran, a similar cyclic ether, from Do et al. [J. Chem. Phys. 134, 144302 (2011)]. In addition, "rotationally averaged" elastic DCSs, calculated using our independent atom model with screened additivity rule correction approach are also reported. Those latter results give integral cross sections consistent with the optical theorem, and supercede those from the only previous study of Milosavljević et al. [Eur. Phys. J. D 40, 107 (2006)].
Reconfigurable ring filter based on single-side-access ring topology is presented. Using capacitive tuning elements, the electrical length of the ring can be manipulated to shift the nominal center frequency to a desired position. A synthesis is developed to determine the values of the capacitive elements. To show the advantage of the synthesis, it is applied to the reconfigurable filter design using RF lumped capacitors. The concept is further explored by introducing varactor-diodes to continuously tune the center frequency of the ring filter. For demonstration, two prototypes of reconfigurable ring filters are realized using microstrip technology, simulated, and measured to validate the proposed concept. The reconfigured filter using lumped elements is successfully reconfigured from 2 GHz to 984.4 MHz and miniaturized by 71% compared to the filter directly designed at the same reconfigured frequency, while, for the filter using varactor-diodes, the frequency is chosen from 1.10 GHz to 1.38 GHz spreading over 280 MHz frequency range. Both designs are found to be compact with acceptable insertion loss and high selectivity.
This paper describes how to employ distributed clock gating to achieve an overall low power design of a programmable waveform generator intended for a neural stimulator. The power efficiency is enabled using global timing control combined with local amplitude distribution over a bus to the local stimulator frontends. This allows the combination of local and global clock gating for complete sub-blocks of the design. A counter and a shifter employed at the local digital stimulator reduce the design complexity for the waveform generation and thus the overall power consumptions. The average power results indicate that 63% power can be saved for the global stimulator control unit and 89-96% power can be saved for the local digital stimulator by using the proposed approach. The circuit has been implemented and successfully tested in a 0.35 µm AMS HVCMOS technology.
Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA) acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0-20 min) of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung's and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung's methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles.
Structural parameters, electronic structure and optical properties of the dialkali metal monotelluride M2Te (M = Li, Na, K and Rb) compounds in the cubic antifluorite structure were investigated via ab initio calculations using the all electron linearized augmented plane wave approach based on density functional theory with and without including spin-orbit coupling (SOC). The exchange-correlation interactions were described within the PBEsol version of the generalized gradient approximation and Tran-Blaha modified Becke-Johnson potential (TB-mBJ). Optimized equilibrium lattice parameters are in excellent accordance with existing measured ones. Computed energy band dispersions show that the studied compounds are large band gap materials. Inclusion of SOC reduces the band gap value compared to the corresponding one calculated without including SOC. Determination of the energy band character and interatomic bonding nature are performed using the densities of states diagrams and charge density distribution map. Linear optical function spectra are predicted for a wide energy range and the origin of the dielectric function spectrum peaks are determined.
Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.
In recent years, plasma-assisted synthesis has been extensively used in large scale production of functional nano- and micro-scale materials for numerous applications in optoelectronics, photonics, plasmonics, magnetism and drug delivery, however systematic formation of these minuscule structures has remained a challenge. Here we demonstrate a new method to closely manipulate mesostructures in terms of size, composition and morphology by controlling permeability at the boundaries of an impermeable plasma surrounded by a blanket of neutrals. In situ and rapid growth of thin films in the core region due to ion screening is among other benefits of our method. Similarly we can take advantage of exceptional properties of plasma to control the morphology of the as deposited nanostructures. Probing the plasma at boundaries by means of observing the nanostructures, further provides interesting insights into the behaviour of gas-insulated plasmas with possible implications on efficacy of viscous heating and non-magnetic confinement.
Field-effect transistors (FETs) have succeeded in modern electronics in an era of computers and hand-held applications. Currently, considerable attention has been paid to direct electrical measurements, which work by monitoring changes in intrinsic electrical properties. Further, FET-based sensing systems drastically reduce cost, are compatible with CMOS technology, and ease down-stream applications. Current technologies for sensing applications rely on time-consuming strategies and processes and can only be performed under recommended conditions. To overcome these obstacles, an overview is presented here in which we specifically focus on high-performance FET-based sensor integration with nano-sized materials, which requires understanding the interaction of surface materials with the surrounding environment. Therefore, we present strategies, material depositions, device structures and other characteristics involved in FET-based devices. Special attention was given to silicon and polyaniline nanowires and graphene, which have attracted much interest due to their remarkable properties in sensing applications.
Clonal selection algorithm and discrete Hopfield neural network are extensively employed for solving higher-order optimization problems ranging from the constraint satisfaction problem to complex pattern recognition. The modified clonal selection algorithm is a comprehensive and less iterative immune-inspired searching algorithm, utilized to search for the correct combination of instances for Very large-scale integrated (VLSI) circuit structure. In this research, the VLSI circuit framework consists of Boolean 3-Satisfiability instances with the different complexities and number of transistors are considered. Hence, a hybrid modified clonal selection algorithm with discrete Hopfield neural network is well developed to optimize the configuration of VLSI circuits with different number of electronic components such as transistors as the instances. Therefore, the performance of the developed hybrid model was assessed experimentally with the standard models, HNNVLSI-3SATES and HNNVLSI-3SATGA in term of circuit accuracy, sensitivity, robustness and runtime to complete the verification process. The results have demonstrated the developed model, HNNVLSI-3SATCSA produced a minimum error (consistently approaching 0), better accuracy (more than 80%) and faster computational time (less than 125 seconds) against changes in the complexity in term of the number of transistors. Furthermore, the developed hybrid model is able to minimize the computational burden and configurational noises for the variant of VLSI circuits.
Doping is the key feature in semiconductor device fabrication. Many strategies have been discovered for controlling doping in the area of semiconductor physics during the past few decades. Electrical doping is a promising strategy that is used for effective tuning of the charge populations, electronic properties, and transmission properties. This doping process reduces the risk of high temperature, contamination of foreign particles. Significant experimental and theoretical efforts are demonstrated to study the characteristics of electrical doping during the past few decades. In this article, we first briefly review the historical roadmap of electrical doping. Secondly, we will discuss electrical doping at the molecular level. Thus, we will review some experimental works at the molecular level along with we review a variety of research works that are performed based on electrical doping. Then we figure out importance of electrical doping and its importance. Furthermore, we describe the methods of electrical doping. Finally, we conclude with a brief comparative study between electrical and conventional doping methods.
Battery Monitoring System (BMoS) is an electronic system that monitors rechargeable battery cells or packs with various parameters, such as battery voltage, current and State-of-Charge (SoC). This system can be used to avoid overcharging or over-discharging of batteries to increase its shelf life. However, BMoS on the market is very expensive and not suitable for low cost embedded systems. As the Arduino Uno is widely used for low cost microcontroller boards, easy programming environment, and open-source platforms for building electronic projects, therefore, this study focuses on Arduino Uno BMoS based system. This system consists of current and voltage sensors, an Arduino Uno microcontroller and a liquid crystal display (LCD). In order to develop this system, there are three objectives to be achieved. First, the relationship between input and output of the sensors must be derived mathematically. The mathematical expression obtained can be verified by connecting and disconnecting the circuit with load and monitoring the value of output sensors. Then, a complete prototype of the BMoS was developed by connecting the LCD, current and voltage sensors to the Arduino Uno microcontroller. The complete prototype was tested using an 11.1 V of Lithium-ion battery and a DC motor as a load. From the results, the current sensor shows zero value when no load is connected as no current flow. The LCD also displays 11.1V of battery voltage when fully charged. Using the developed system, the user can monitor the current, the voltage and the SoC of the battery to ensure the battery is not overcharged and overused. The development of the BMoS can help to monitor the operation and performance of the batteries in any electronic systems. At the end of this study, the complete BMoS prototype gives benefits to the user and makes work easier.
Pulse Shaping Amplifier (PSA) is an essential component in nuclear spectroscopy system. This
amplifier has two functions; to shape the output pulse and performs noise filtering. In this paper,
we describe the procedure for the design and development of a pulse shaping amplifier which can
be used in a nuclear spectroscopy system. This prototype was developed using high performance
electronics devices and assembled on a FR4 type printed circuit board. Performance of this
prototype was tested by comparing it with an equivalent commercial spectroscopy amplifier (Model
Silena 7611). The test results showed that the performance of this prototype was comparable
to the commercial spectroscopic amplifier.