Design of fully differential fast SCL Schmitt-trigger delay element with tunable delay and hysteresis in design and run-time

Tuning the delay of the circuit during the circuit performance can give a chance to a circuit to reduce Process, Voltage and Temperature (PVT) effects on delay and frequency by resetting its delay in feedback. This paper presented a full differential Schmitt-trigger (ST) with tunable delay and hysteresis. The delay-hysteresis setting is done in the design phase by tuning the biasing current, sizing, bias voltage and also during the execute phase (run time) by a digital bit and restructuring the circuit and delay route. The presented ST can have high and low delays with different frequencies using a digital bit in the circuit. This can help the band selection for multi-band applications. A Flip Voltage Follower (FVF) circuit is used for the current tail to increase the current and increase the frequency bands. In this Schmitt-trigger delay changes associated with restructuring result in a 40 % power reduction. A circuit analysis for the equivalent circuit of the presented circuit has also been done and the factors affecting the frequency and delay change have been analyzed and investigated in the simulation. Monte Carlo and PVT analysis have also been performed for circuit accuracy. Power changing with an incremental delay in CMOS is improved and almost monotonous by designing Source-Coupled-Logic (SCL) Schmitt-trigger

Star-Shaped Coils in the Transmitter Array for Receiver Rotation Tolerance in Free-Moving Wireless Power Transfer Applications

Wireless power is one of the new promising technologies for IoT applications. The use of arrays for power transfer to free-moving objects has revolutionized wireless power transmission (WPT) applications. Herein, we present an extendable platform for transmitting power to a moving object receiving power from an array. The transmitter (TX) consists of two overlapping layers of square planar coils rotated 45 degrees to each other to provide the best electromagnetic flux coverage. Each layer consists of four coils to further control the power supply to the small receiver (RX) coil. This overlapping star-shaped array is stimulated automatically by a power amplifier. This smart stimulation can deliver uniform power to the receiver regardless of rotation and misalignment inconsistencies by using the geometry of the transmitter array. Moreover, by changing the direction of the current of each small square component in each array using the flower-shaped current, a receiver coil perpendicular to the transmitter’s plate can obtain power comparable with conventional structures. We use ADS-HFSS simulation to verify the fabrication and measurement results. The proposed transmitter achieves an average of 18.2% power transfer efficiency (PTE) to RX and at 90° angular misalignment, 11.5% PTE, while the conventional structure transfers no power to the perpendicular RX coil. A future application of the transmitter can be the investigation of the neurobehavioral of free-moving animals and brain–machine interface studies in medicine

Study on efficacy of hepatitis B immunization in vaccinated beta-thalassemia children in Tehran

Objective: In thalassemic children, hepatitis B virus (HBV) infection is common, thus immunization against HBV will reduce and prevent the rate of infection. The aim of this study was to evaluate the efficacy of HBV immunization and the prevalence of HBV infection in beta-thalassemic children in Tehran. Methods: To assess the efficacy of immunization and determine the immune response of children with beta-thalassemia, sera of 99 children who had received three doses (10/20 μg) of recombinant HBV vaccine in months 0, 1, 6, were selected and tested for HBs-Ag, HBs-Ab and anti-HBc by enzyme linked immunosorbent assay method. Also, these sera were tested for HBV DNA using nested-PCR (polymerase chain reaction) method. Findings: In 99 beta-thalassemic children, 89 (89.9 %) were anti-HBs positive (responders) and 10 (10.1%) anti-HBs negative (non-responders). Three cases (3.03%) were anti-HBc positive and 1(1.01%) was HBs-Ag positive. HBV DNA was not detected in any of them. Conclusion: Our results have revealed that hepatitis B vaccine is highly immunogenic for thalassemic children and particularly well tolerated

Using Overlapped Resonators in Wireless Power Transfer for Uniform Electromagnetic Field and Removing Blank Spots in Free Moving Applications

We propose an induction link based on overlapping arrays to eliminate blank spots on the electromagnetic field for moving object applications. We use two arrays of four aligned coils that have a 50% overlap between the two plates. This mechanism compensates for the internal coil power drop at positions in the boundaries between two adjacent external coils. We showed that if these plates are excited, a uniform electromagnetic field is created in the movement direction of the moving object. This uniform electromagnetic field distribution will result in a constant receiving power at all points in the path of the moving internal coil with the same power consumption of one coil excitation. Power delivery to the moving object tolerance reaches 10% at most, while, in non-overlapped scenarios, it is approximately 50%. In addition, according to the theoretical calculations, printed circuit coils (PCB) for the array are designed for maximum efficiency. We found that the change in distance and dimensions of the receiver coil has a linear effect on power and efficiency. Moreover, a Specific Absorption Rate (SAR) simulation was performed for biocompatibility. In this paper, we investigate and record a 68% electrical power efficiency for the fabricated system. The array consists of eight transmitters coils of the same size and shape and a receiver coil at a distance of 4 cm. Furthermore, the fabricated coil has shown improved efficiency compared to similar studies in the literature and introduces a promising structure for bio-test applications

Star-Shaped Coils in the Transmitter Array for Receiver Rotation Tolerance in Free-Moving Wireless Power Transfer Applications

Wireless power is one of the new promising technologies for IoT applications. The use of arrays for power transfer to free-moving objects has revolutionized wireless power transmission (WPT) applications. Herein, we present an extendable platform for transmitting power to a moving object receiving power from an array. The transmitter (TX) consists of two overlapping layers of square planar coils rotated 45 degrees to each other to provide the best electromagnetic flux coverage. Each layer consists of four coils to further control the power supply to the small receiver (RX) coil. This overlapping star-shaped array is stimulated automatically by a power amplifier. This smart stimulation can deliver uniform power to the receiver regardless of rotation and misalignment inconsistencies by using the geometry of the transmitter array. Moreover, by changing the direction of the current of each small square component in each array using the flower-shaped current, a receiver coil perpendicular to the transmitter’s plate can obtain power comparable with conventional structures. We use ADS-HFSS simulation to verify the fabrication and measurement results. The proposed transmitter achieves an average of 18.2% power transfer efficiency (PTE) to RX and at 90° angular misalignment, 11.5% PTE, while the conventional structure transfers no power to the perpendicular RX coil. A future application of the transmitter can be the investigation of the neurobehavioral of free-moving animals and brain–machine interface studies in medicine.Electronic Components, Technology and Material

Investigating Organic Vapor Sensing Properties of Composite Carbon Nanotube-Zinc Oxide Nanowire

The low operating temperature of nanowire gas sensors along with their high surface-to-volume ratio are two factors that make gas sensors more practical. In this paper, the growth of ZnO nanowires on a vertically aligned CNT forest is reported. The utilized method for ZnO growth was a rapid microwave-assisted hydrothermal route, which facilitates low-temperature and ultra-fast fabrication. Organic vapor sensing properties of fabricated samples were studied in response to different alcoholic vapors at a wide operating temperature range of 25 to 300◦C. Enhancement of the gas response was observed with increasing operating temperature. Moreover, the effect of the ZnO nanowire length on organic vapor sensing properties of CNT-ZnO samples was investigated. Results proved that CNT-ZnO samples with long ZnO wires exhibit higher sensitivity to examined analytes. Different length ZnO nanowires were attained via variation of the microwave exposure time and power. Fabrication parameters were selected based on numerous runs. The length of ZnO synthesized at each distinct run was calculated based on SEM micrographs of the samples.Bio-Electronic

Using Overlapped Resonators in Wireless Power Transfer for Uniform Electromagnetic Field and Removing Blank Spots in Free Moving Applications

We propose an induction link based on overlapping arrays to eliminate blank spots on the electromagnetic field for moving object applications. We use two arrays of four aligned coils that have a 50% overlap between the two plates. This mechanism compensates for the internal coil power drop at positions in the boundaries between two adjacent external coils. We showed that if these plates are excited, a uniform electromagnetic field is created in the movement direction of the moving object. This uniform electromagnetic field distribution will result in a constant receiving power at all points in the path of the moving internal coil with the same power consumption of one coil excitation. Power delivery to the moving object tolerance reaches 10% at most, while, in non-overlapped scenarios, it is approximately 50%. In addition, according to the theoretical calculations, printed circuit coils (PCB) for the array are designed for maximum efficiency. We found that the change in distance and dimensions of the receiver coil has a linear effect on power and efficiency. Moreover, a Specific Absorption Rate (SAR) simulation was performed for biocompatibility. In this paper, we investigate and record a 68% electrical power efficiency for the fabricated system. The array consists of eight transmitters coils of the same size and shape and a receiver coil at a distance of 4 cm. Furthermore, the fabricated coil has shown improved efficiency compared to similar studies in the literature and introduces a promising structure for bio-test applications.Electronic Components, Technology and Material

The sensitivity enhancement of TiO₂-based VOCs sensor decorated by gold at room temperature

Detection of hazardous toxic gases for air pollution monitoring and medical diagnosis has attracted the attention of researchers in order to realize sufficiently sensitive gas sensors. In this paper, we fabricated and characterized a Titanium dioxide (TiO2)-based gas sensor enhanced using the gold nanoparticles. Thermal oxidation and sputter deposition methods were used to synthesize fabricated gas sensor. X-ray diffraction analysis was used to determine the anatase structure of TiO2samples. It was found that the presence of gold nanoparticles on the surface of TiO2enhances the sensitivity response of gas sensors by up to about 40%. The fabricated gas sensor showed a sensitivity of 1.1, 1.07 and 1.03 to 50 ppm of acetone, methanol and ethanol vapors at room temperature, respectively. Additionally, the gold nanoparticles reduce 50 s of response time (about 50% reduction) in the presence of 50 ppm ethanol vapor; and we demonstrated that the recovery time of the gold decorated TiO2sensor is less than 40 s. Moreover, we explain that the improved performance depends on the adsorption-desorption mechanism, and the chemical sensitization and electronic sensitization of gold nanoparticles.Electronic Components, Technology and Material