RF-DC power conversion of Schottky diode fabricated on AlGaAs/GaAs heterostructure for on-chip rectenna device application in nanosystems

The Schottky diodes enjoined with coplanar waveguides are investigated for applications in on-chip rectenna device applications without insertion of a matching circuit. The design, fabrication, DC characteristics and RF-to-DC conversion of the AlGaAs/GaAs HEMT Schottky diode is presented. The RF signals are well converted by the fabricated Schottky diodes with cut-off frequency up to 25 GHz estimated in direct injection experiments. The outcomes of these results provide conduit for breakthrough designs for ultra-low power on-chip rectenna device technology to be integrated in nanosystems

Undoped and Zn-doped NiO nanosheet/nanoflower-like films-based humidity sensor fabricated via immersion method

The nickel oxide (NiO) nanosheet/nanoflower-like (NS/NF) films-based humidity sensors doped with zinc (Zn) and without doping were successfully deposited on the NiO seed layer-coated glass substrates using the immersion method. The addition of 1 atomic percent of Zn concentration into pristine NiO has a significant influence on the structural and morphological properties as well as humidity sensing performance as there are changes in its crystal parameters. The Zn doping increased the dislocation density and tensile strain but shrank the average crystallite size (D) of NiO. The average D was estimated from three X-ray diffraction peaks of undoped and Zn-doped NiO NS/NF films, and the calculated values are 16.3 and 12.3 nm, respectively. The NiO surface morphology and the thickness are also affected by the Zn doping. The nanoflower (NF) shape and pattern on the nanosheet (NS) layer disappeared and dispersed obviously. Meanwhile, the NS thickness sharply decreased from 910 to 410 nm. By using silver contact as a sensing measurement electrode, the sensitivity of the Zn-doped NiO-based humidity sensor is increased to 78 compared to undoped NiO with a sensitivity of 30

Fabrication Process of n-AlGaAs/GaAs Schottky Diodes for on-chip Direct Integrated with Dipole Antenna

Schottky diodes are fabricated on n-Aluminium Gallium Arsenide / Gallium Arsenide (n-AlGaAs/GaAs) high-electron-mobility-transistor (HEMT) structure due to availability of high electron mobility and capability of fast switching performance. The processing steps used in the fabrication are the conventional steps used in standard GaAs processing. The ohmic and Schottky contacts of Schottky diodes are facilitated with ground-signal-ground (G-S-G) coplanar waveguide (CPW) transmission line structure so that it may provide the possibility of direct on-chip integration without insertion of a matching circuit with dipole antenna

Optoelectronic properties of improved GaN semiconductor on Si (111) using growth approaches and different interlayer’s

The crystalline quality of wider direct band gap semiconductor (3.4 eV) h-GaN epilayer grown on Si (111) is evaluated by different growth approaches and by using different interlayer’s. The investigations of GaN epilayer crystal quality for the template of converted porous GaN layer formed by novel nitridation process of thin (2 and 0.5 μm) GaAs layer on Si (111) and on C+ ion implanted very thin SiC layer formed on Si (111) and grown ambient effect are made. Epilayer grown on thinner non-isoelectronic converted SiC templates is found to broaden its PL line width whereas epilayer grown on porously converted GaN layer fromed from iso- electronic GaAs (111) layer on Si (111) is found narrow line width. H2 ambient grown film better crystalline quality and higher PL Ex. peak energy is found as compared to N2 ambient grown film. Low temperature PL measurement, similarity between defect related donor-acceptor peaks (DAP) to defect related yellow band luminescence at the room temperature PL measurement is also found. Grown epilayer different characterization reveals better crystalline quality h-GaN is achieved by using thin isoelectronic GaAS interlayer on Si (111) with H2 grown ambient

Influence of Pretransplant Restrictive Lung Disease on Allogeneic Hematopoietic Cell Transplantation Outcomes

We conducted a 15-year retrospective cohort study to determine the prevalence of restrictive lung disease prior to allogeneic hematopoietic cell transplant (HCT), and to assess whether this was a risk factor for poor outcomes. 2545 patients were eligible for the analysis. Restrictive lung disease was defined as a total lung capacity (TLC) <80% of predicted normal. Chest x-rays and /or computed tomography scans were reviewed for all restricted patients to determine whether lung parenchymal abnormalities were unlikely or highly likely to cause restriction. Multivariate Cox-proportional hazard and sensitivity analyses were performed to assess the relationship between restriction and early respiratory failure and nonrelapse mortality. Restrictive lung disease was present in 194 subjects (7.6%) prior to transplantation. Among these cases, radiographically apparent abnormalities were unlikely to be the cause of the restriction in 149 (77%) subjects. In unadjusted and adjusted analyses, the presence of pulmonary restriction was significantly associated with a 2-fold increase in risk for early respiratory failure and nonrelapse mortality, suggesting that these outcomes occurring in the absence of radiographically apparent abnormalities may be related to respiratory muscle weakness. These findings suggest that pulmonary restriction should be considered as a risk factor for poor outcomes after transplant

Fabrication, structural, optical, electrical, and humidity sensing characteristics of hierarchical NiO nanosheet/nanoball fower like structure flms

In this work, nickel oxide (NiO) nanosheet/nanoball-fower-like structures (NSBS) were directly grown on a NiO seed-coated glass substrate using a low-temperature immersion method at 75 ºC. The thickness, or density, of the nanoball-fower-like structures difered based on the following samples order: NSBS1< NSBS2< NSBS3. The synthesised NSBS flms were investigated in terms of structural, optical, electrical, and humidity sensing characteristics. The X-ray difraction (XRD) analysis revealed that the NSBS samples corresponded to the face-centred cubic NiO with fve difraction patterns indexed to the (111), (200), (220), (311), and (222) planes. The interplanar spacing, lattice parameter, unit cell volume, strain, and stress were also determined from the XRD results. The transmittance spectra showed that the NSBS samples had a transparency of more than 30% in the visible region. The optical bandgap values for the NSBS samples were estimated in the range between 3.72 and 3.75 eV, which is directly related to their lattice expansion and defect characteristics. The current–voltage and Hall efect measurement results revealed that the NSBS2 displayed good electrical properties with the resistance, hole concentration, and hole mobility values of 7.84 MΩ, 8.71×1015 hole/cm−3, and 1.88×102 cm2 /V s, respectively. The NSBS samples performed well for humidity sensing with the highest sensitivity value of 169 being obtained for the NSBS2. These humidity sensing results correlated well with their structural, optical, and electrical characteristics

Towards real-time visual biometric authentication using human face for healthcare telepresence mobile robots

Telepresence Mobile Robots have prominent attributes in many fields as it provides virtual presence for human robot interaction. The deployment of this robot in healthcare sector has improved patient care and health. The vision system in a telepresence robot allows two way audiovisual communication between people at different location. In spite of such advancement, the manual way of controlling a robot to recognise and track people during an emergency is not favourable for a long duration. To circumvent this problem, biometric method using human face is proposed in this research which is implemented on Medical Telediagnosis Robot. This paper details the design of the face recognition and tracking system with four automated modules which are motion detection, face detection, face recognition and face tracking. The modules are developed with different algorithm and tested individually to ensure the stability of the system. Artificial Intelligence technique was applied at the face recognition stage while a two degree of freedom mechanism for actuator control was used at face tracking stage. A sequential mode operation is proposed to reduce the execution time in a real-time environment. To achieve this, only one module is operated at each time. A Graphical User Interface was developed to ease the users at the local and robot environment. The system is designed in LabVIEW platform. The biometric system proposed with hybrid algorithm at each module adapts for face images detected at different distances, poses and lighting condition. This system was tested in real-time and has an execution time of 55ms and 98% accuracy. The stand alone system designed for Medical Telediagnosis Robot can be will be very fruitful for various biometric system using facial technology

Current concepts on the role of inflammation in COPD and lung cancer

Chronic obstructive pulmonary disease (COPD) and lung cancer are leading cause of death, and both are associated with cigarette smoke exposure. It has been shown that 50–70% of patients diagnosed with lung cancer suffer from COPD, and reduced lung function is an important event in lung cancer suggesting an association between COPD and lung cancer. However, a causal relationship between COPD and lung tumorigenesis is not yet fully understood. Recent studies have suggested a central role of chronic inflammation in pathogenesis of both the diseases. For example, immune dysfunction, abnormal activation of NF-κB, epithelial-to-mesenchymal transition, altered adhesion signaling pathways, and extracellular matrix degradation/altered signaling are the key underlying mechanisms in both COPD and lung cancer. These parameters along with other processes, such as chromatin modifications/epigenetic changes, angiogenesis, and autophagy/apoptosis are altered by cigarette smoke, are crucial in the development of COPD and lung cancer. Understanding the cellular and molecular mechanisms underlying these processes will provide novel avenues for halting the chronic inflammation in COPD and devising therapeutic strategies against lung cancer

Simple speech controlled home automation system using android devices

Speech control is an emerging innovative method to accomplish control tasks. In this work, a system is created to control two of the most human interactive activities; switching on and off of lights and fans using ATMEGA-328P microcontroller and Android OS’ speech recognition. This system improves the living standard by making life easier and increasing productivity. The development of the prototype will be made within a low budget in hopes to attract people