Improvement in Opto-Electrical Properties of GaN MSM Photodetector by Contact Work-Function Selection

Overall , this work evaluates the role of different metal contacts in improving electrical properties of GaN MSM (metal-semiconductor-metal) photodetector. The metal contacts were investigated in this work are AI , In, Pt. ITO and ZnO. Prior to the metalization , GaN layer was deposited on m-plane sapphire (AI203) substrate using electron beam (e-beam) evaporator, followed by ammonia annealing treatment to improve 111 -V stoichiometric balance. Subsequently , a metal mask consisting of two terminals, each with 3 inter-digitized fingers was aligned over -9 mm2 of the GaN samples. Contacts on each MSM photodetector were deposited by either RF/DC sputtering. Next each GaN MSM photodetector were annealed at 400 °C for 10 minutes in ambient air to diffuse the metal contact layer into th e GaN layer. The bes t spectral response of th e GaN MSM was observed at -360 nm GaN MSM photodetector with Pt contact shows a Schottky IV curve due to the large contact work -function . On the other hand. ohmic IV curve was observed on the remain ing GaN MSM photodetector IV measurement under dark and illuminated conditions shows a gain of -34 times between bias voltage or 1.5 V to 5.0 V. Responsivity measurement under pulsing UV light illumination was conducted to investigate the rise and fall time for each GaN MSM photodetector

Experimental study to identify common engine part load conditions between Malaysian city driving and NEDC test

This paper describes an experimental study conducted to identify the common engine part load conditions between Malaysian city driving and NEDC (New European Driving Cycle) test on a 4 cylinder gasoline fuelled engine, with multi-point fuel injection system, and continuous variable transmission vehicle. This is to pinpoint a regional area from the part load map in the attempt to strategize key technologies such as CDA (Cylinder Deactivation) or CNG (Compressed Natural Gas). Technologies such as CDA or CNG do not operate at all engine operations. Due to certain drawbacks, the operation of the technologies must be strategized to obtain most benefit from the engine. With the knowledge of the common part load region, these technologies could be integrated and strategized into the region to reduce overall fuel consumption. With improvements in fuel consumption respective to the identified common part load operations, the overall fuel consumption benefit does not only serve the legislation but also most importantly benefit the local consumers who travel on Malaysian roads. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved

Review on UV-LEDs: State of the Art and Challenges Ahead

The latest challenge of LEOs is to residing themselves in advanced ultra-violet (UV) lighting, which involves industrial UV curing (e. coatings , resins. adhesives). medical and scientific (e.g. pl1ototherapy, DNA sensing). sterilization (bacterial disinfection , water purification, skin therapy), security (counterfeit detection and forensics) and horticulture lighting New market research by Markets and Markets reports that the UV LED market is expected to reach USD 369.58 million by 2020. So far , high energy AI,Ga1.xN materials are the best solution to product UV emission LEOs in the wavelength range below 390 nm. Progress on AIXGa1-XN based UV LEOs is on-going with external quantum efficiency (EQE) above than 10% at present. However, the EQE of most of th e UV-B (320-280 nm) and UV-C (280-210 nm) LEOs are still in single-digit percentage range and unable to cope witt1 th e current deep UV lighting market demand. The output power of such LEOs is few mWs while limited lifetime is tess than a thousand hours. From fundamental point of view, producing UV-LEDs below 360 nm requires more AI composition in the AIXGa1-XN based active region and high growth temperature above 11 00°C . Unfortunately, incorporation of AI atoms into the AIXGa1-XN lattice structure is not an easy process as the atoms readily react with oxygen, while parasitic reaction beco mes much more serious at high temperature. These effects significantly kill the overall efficiency of LEDs. In this talk, novel published techniques to solve the above problems will be rev iewed and near-future work in developing UV-LEDs at INOR. USM will be presented

Electrospun nanofiber membranes as ultrathin flexible supercapacitors

A highly flexible electrochemical supercapacitor electrode was developed with a novel metal oxide-reinforced nanofiber electrode by utilizing a solution-based electrospinning technique. The facile fabrication steps involved the introduction of metal precursors into a polymeric solution, which was subjected to an in situ electrospinning process. The electrospun polymeric web with metallic ingredients was then subjected to an oxidative stabilization process that induced the formation of metal oxide nanoparticles within the polymer structure. Finally, the metal oxide nanoparticles incorporated with nanofibers were obtained using a carbonization process, thus converting the polymer backbones into a carbon-rich conductive nanofiber structure. The fabricated nanofibers were decorated and implanted with metal oxide nanoparticles that had a surface-decorated structure morphology due to the solubility of the precursors in the reaction solution. The electrochemical performance of the fabricated metal oxide reinforced with nanofiber electrodes was investigated as an electrochemical system, and the novel morphology significantly improved the specific capacitance compared to a pristine carbon nanofiber membrane. As a result of the uniform dispersion of metal oxide nanoparticles throughout the surface of the nanofibers, the overall capacitive behavior of the membrane was enhanced. Furthermore, a fabricated free-standing flexible device that utilized the optimized nanofiber electrode demonstrated high stability even after it was subjected to various bending operations and curvatures. These promising results showed the potential applications of these lightweight, conductive nanofiber electrodes in flexible and versatile electronic devices

Application of knowledge-oriented convolutional neural network for causal relation extraction in South China Sea conflict issues

Online news articles are an important source of information for decisions makers to understand the causal relation of events that happened. However, understanding the causality of an event or between events by traditional machine learning-based techniques from natural language text is a challenging task due to the complexity of the language to be comprehended by the machines. In this study, the Knowledge-oriented convolutional neural network (K-CNN) technique is used to extract the causal relation from online news articles related to the South China Sea (SCS) dispute. The proposed K-CNN model contains a Knowledge-oriented channel that can capture the causal phrases of causal relationships. A Data-oriented channel that captures the position information was added to the K-CNN model in this phase. The online news articles were collected from the national news agency and then the sentences which contain relation such as causal, message-topic, and product-producer were extracted. Then, the extracted sentences were annotated and converted into lower form and base form followed by transformed into the vector by looking up the word embedding table. A word filter that contains causal keywords was generated and a K-CNN model was developed, trained, and tested using the collected data. Finally, different architectures of the K-CNN model were compared to find out the most suitable architecture for this study. From the study, it was found out that the most suitable architecture was the K-CNN model with a Knowledge-oriented channel and a Data-oriented channel with average pooling. This shows that the linguistic clues and the position features can improve the performance in extracting the causal relation from the SCS online news articles

First order piecewise collocation solution of Fredholm integral equation second kind by using gauss-seidel iteration

We determine the approximation solution of first-order piecewise via polynomial collocation with first-order Quadrature scheme on Fredholm integral equations of second kind. This discretization has derived the formation for solving piecewise approximation equation in which constructing the linear system. In order to get the approximation solutions, the Gauss-Seidel method has been stated as a linear solver in which its formulation has been constructed and implemented in this study. The combination of the iterative method of GS with the first-order piecewise polynomial via collocation with first-order Quadrature scheme has shown that performance of GS method is excel than Jacobi method in the matter of iterations number and completion time

Exponential Tapered Balun with Different Sizes for UWB Elliptical Dipole Antenna

This work presents a broadband tapered balun with different sizes using nonlinear transition particularly suitable for planar and three-dimensional (3-D) dipole antennas for ultra-wideband (UWB) applications such as communication, radar systems and geolocation precision. Four baluns with wideband microstrip-to-parallel-strip transition using an elliptical structure for an elliptical dipole antenna are proposed. The initial balun structure consists of a nonlinear profile with a quarter-wavelength for both height and width. By studying the current distributions at the balun surface, it can be reduced to 25%, 50% and 75% from the original size. Measured results based on the reflection coefficients for all baluns are shown to be better than -10 dB from 1.0 GHz to 10 GHz. These baluns are integrated with an elliptical dipole which acts as a feeding circuit. Eight set of antennas with a planar and 3-D configurations with four different sizes are proposed in this work. The planar configurations are named as Planar 1, Planar 2, Planar 3 and Planar 4 while the 3-D configurations are named as 3D Dipole 1, 3D Dipole 2, 3D Dipole 3 and 3D Dipole 4, respectively. The results show that all antennas with the proposed baluns operates within the UWB frequency range

Semi-automatic liquid filling system using NodeMCU as an integrated Iot Learning tool

Computer programming and IoT are the key skills required in Industrial Revolution 4.0 (IR4.0). The industry demand is very high and therefore related students in this field should grasp adequate knowledge and skill in college or university prior to employment. However, learning technology related subject without applying it to an actual hardware can pose difficulty to relate the theoretical knowledge to problems in real application. It is proven that learning through hands-on activities is more effective and promotes deeper understanding of the subject matter (He et al. in Integrating Internet of Things (IoT) into STEM undergraduate education: Case study of a modern technology infused courseware for embedded system course. Erie, PA, USA, pp 1–9 (2016)). Thus, to fulfill the learning requirement, an integrated learning tool that combines learning of computer programming and IoT control for an industrial liquid filling system model is developed and tested. The integrated learning tool uses NodeMCU, Blynk app and smartphone to enable the IoT application. The system set-up is pre-designed for semi-automation liquid filling process to enhance hands-on learning experience but can be easily programmed for full automation. Overall, it is a user and cost friendly learning tool that can be developed by academic staff to aid learning of IoT and computer programming in related education levels and field

Electromagnetic Wave Absorption Properties of Novel Green Composites Coconut Fiber Coir and Charcoal Powder over X-band Frequency for Electromagnetic Wave Absorbing Applications

This paper presents the electromagnetic wave (EW) absorption properties in terms of complex permittivity and permeability of novel green composites coconut fiber coir and charcoal powder materials. The samples were fabricated using the raw agricultural waste coconut fiber coir, charcoal powder, epoxy resin and hardener with varied composition. The dielectric properties of the materials were characterized using two-port waveguide measurement method over the X-band frequency (8.2 – 12.4GHz). The average permittivity value measured is approximately 3.00 with 10wt% charcoal has the highest permittivity of 3.59. Apart from that, all samples exhibit good reflection loss of better than -25dB which means more than 99% absorption rate. The result shows the composite material is a promising organic material for electromagnetic absorber applications