A sector analysis for RFID technologies: fundamental and technical analysis for financial decision making problems

Automatic identification technologies have been used in a wide range of applications for reducing the amount of time and labor needed to input data and improving data accuracy. As an important automatic identification technology, radio frequency identification (RFID) technologies allow contactless reading and these technologies are particularly successful in manufacturing and other environments where traditional identification technologies such as bar codes can not perform well. By integrating the RFID technology into their business models, companies may save time, lower labor cost, improve products quality and provide better service. RFID is the wireless technology that uses RF communication to identify, track and manage objects and collect and store data. RFID technology enables companies to develop applications that create value by tracking and identifying objects, animals or people. Business applications of RFID technology can be seen in areas such as manufacturing, supply chain management, software integration, security systems, asset tracking and many others. RFID technology was predicted to be one of the “top ten” technologies in 2004 by CNN. Although, the RFID market is less than five years old, it has been applied to many different industries, from retail industry to logistics, or from healthcare to service business industry – and it is still growing. Particularly, RFID has fundamental influences on today's retailing and supply chain management for applications like asset tracking the inventory control and management. RFID technology also finds major application in mobile phones and is widely used in toll collection of highways, for payments in restaurants, vending machines, retail and parking lots. There are a wide range of RFID systems currently being used or being developed. Examples to these systems include but not limited to the following; automatic vehicle and personnel access control for security (Simpson, 2006), airport passenger and baggage tracking (Ferguson, 2006), tracing blood for cutting down errors such as giving patients wrong blood types (Ranger, 2006), payment process systems (Ramachandran, 2006), production control in manufacturing (Liu & Miao, 2006), transfusion medicine (Knels, 2006) real-time inventory control by automated identification of items in warehouses, tracking and management of physical files, tracking of books in the libraries (Shadid, 2005). For some other applications, interested reader is referred to (Finkenzeller, 2003; Smith, 2004). RFID solution providers claim that their technology and solutions bring significant benefits and have valuable advantages in practice. As new RFID solutions being developed and more RFID tags and equipments being used, these solutions will become more cost effective and RFID businesses are expected to grow rapidly. Since RFID is fairly new, it’s difficult to measure resulting sales increases or heightened customer satisfaction quotients. On the other hand, according to IDC estimation (IDC is a subsidiary of International Data Group, a leading technology media, research, and events company and provider of market intelligence, advisory services, and events for the information technology, telecommunications, and consumer technology markets), companies in the retail sector will spend nearly $1.3 billion on RFID in their supply chain operations in 2008, compared to about$91.5 million in 2003 which corresponds to annual growth rate of 70 percent. In a similar look; the Wireless Data Research Group projected that the global market for RFID increased from $1 billion in 2003 to$3 billion in 2007 (Asif & Mandviwalla, 2005). There are two major drivers of this growth. The first one is the adoption of RFID technology by major retailers and government agencies. The second one is the reduction in the price of RFID tags, readers, and IT systems required to deploy RFID. Given the huge potential of RFID technology, there has been a huge emergence of RFID specialty companies and the development of RFID practices within many market-leading companies. Due to huge emergence, it is desirable to make a sector analysis. In this study, we perform a sector analysis for RFID technologies for researchers and analysts. We investigate public RFID companies traded on the stock exchange markets, summarize their financial performance, describe their RF products, services, and applications, and perform fundamental and technical analysis

A study of Neospora caninum antibody seroprevalence ın dairy cows in Turkey

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗNeospora caninum is a intracellular protozoan parasite and is one of the major causes of repeated abortions, foetal malformations, pre-term deliveries, stillbirth and possible loss of milk yield in livestock. The presence of specific antibodies against N. caninum in the blood serum of dairy cows is investigated in the present study. A total of 184 blood serum samples of dairy cows were examined in Bursa province in the Marmara Region. N. caninum antibodies were measured using an indirect enzyme-linked immunosorbent assay (ELISA) (The Svanovir Neospora-Ab ELISA). From the total sample, antibodies to N. caninum were detected in 62 of the 184 examined cows (33.3%) and neurological findings were seen in a calf

Electron transport in Ga-rich InxGa1-xN alloys

WOS: 000249810900060Resistivity and Hall effect measurements on n-type undoped Ga-rich InxGa1-xN (0.06 <= x <= 0.135) alloys grown by metal-organic vapour phase epitaxy (MOVPE) technique are carried out as a function of temperature (15-350K). Within the experimental error, the electron concentration in InxGa1-xN alloys is independent of temperature while the resistivity decreases as the temperature increases. Therefore, 1nxGai_x1V (0.06 <= x <= 0.135) alloys are considered in the metallic phase near the Mott transition. It has been shown that the temperature-dependent metallic conductivity can be well explained by the Mott model that takes into account electron-electron interactions and weak localization effects

The temperature dependence of the inelastic scattering time in InGaN grown by MOVPE

Low temperature electrical measurements of the resistivity, the Hall effect and the magnetoconductivity were performed on an InGaN sample having an electron concentration far above the critical value for the metalinsulator transition. Weak localization effect and two-band model were used to analyze the magnetoconductivity data. The temperature dependence of the inelastic scattering time was extracted from the magnetoconductivity data at low temperatures. It was found that the inelastic scattering time is proportional to T⁻¹.⁶³, suggesting that electron–electron interactions are dominant

Determination of two-dimensional electron and hole gas carriers in AlGaN/GaN/AlN heterostructures grown by Metal Organic Chemical Vapor Deposition

Cataloged from PDF version of article.Resistivity and Hall effect measurements on nominally undoped Al0.25Ga0.75N/GaN/AlN heterostructures grown on sapphire substrates prepared by metal organic chemical vapor deposition have been carried out as a function of temperature (20-300 K) and magnetic field (0-1.4 T). Variable magnetic field Hall data have been analyzed using the improved quantitative mobility spectrum analysis technique. The mobility and density of the two-dimensional electron gas at the AlGaN/GaN interface and the two-dimensional hole gas at the GaN/AIN interface are separated by quantitative mobility spectrum analysis. The analysis shows that two-channel conduction is present in nominally undoped Al0.25Ga0.75N/GaN/AlN heterostructures grown on sapphire substrate. (c) 2007 Elsevier B.V All rights reserved

Investigation of AlInN HEMT structures with different AlGaN buffer layers grown on sapphire substrates by MOCVD

Cataloged from PDF version of article.We investigate the structural and electrical properties of AlxIn1-xN/AlN/GaN heterostructures with AlGaN buffers grown by MOCVD, which can be used as an alternative to AlInN HEMT structures with GaN buffer. The effects of the GaN channel thickness and the addition of a content graded AlGaN layer to the structural and electrical characteristics were studied through variable temperature Hall effect measurements, high resolution XRD, and AFM measurements. Enhancement in electron mobility was observed in two of the suggested AlxIn1-xN/AlN/GaN/Al0.04Ga0.96N heterostructures when compared to the standard AlxIn1-xN/AlN/GaN heterostructure. This improvement was attributed to better electron confinement in the channel due to electric field arising from piezoelectric polarization charge at the Al0.04Ga0.96N/GaN heterointerface and by the conduction band discontinuity formed at the same interface. If the growth conditions and design parameters of the AlxIn1-xN HEMT structures with AlGaN buffers can be modified further, the electron spillover from the GaN channel can be significantly limited and even higher electron mobilities, which result in lower two-dimensional sheet resistances, would be possible. (C) 2012 Elsevier B.V. All rights reserved

Electron transport properties in Al0.25Ga0.75N/AIN/GaN hetrostructures with different InGaN back barrier layers and GaN channel thickness grown by MOCVD

Cataloged from PDF version of article.The electron transport properties in Al0.25Ga0.75N/AlN/GaN/InxGa1-xN/GaN double heterostructures with various indium compositions and GaN channel thicknesses were investigated. Samples were grown on c-plane sapphire substrates by MOCVD and evaluated using variable temperature Hall effect measurements. In order to understand the observed transport properties, various scattering mechanisms, such as acoustic phonon, optical phonon, interface roughness, background impurity, and alloy disorder, were included in the theoretical model that was applied to the temperature-dependent mobility data. It was found that low temperature (T 160 K), optical phonon scattering is the dominant scattering mechanism for AlGaN/AlN/GaN/InGaN/GaN heterostructures. The higher mobility of the structures with InGaN back barriers was attributed to the large conduction band discontinuity obtained at the channel/buffer interface, which leads to better electron confinement. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Electronic transport characterization of AlGaN/GaN heterostructures using quantitative mobility spectrum analysis

Cataloged from PDF version of article.Resistivity and Hall effect measurements in nominally undoped Al0.25Ga0.75N/GaN heterostructures grown on sapphire substrate by metal-organic chemical vapor deposition are carried out as a function of temperature (20-350 K) and magnetic field (0-1.5 T). The measurement results are analyzed using the quantitative mobility spectrum analysis techniques. It is found that there is strong two-dimensional electron gas localization below 100 K, while the thermally activated minority carriers with the activation energies of similar to 58 and similar to 218 meV contribute to the electron transport at high temperatures. (C) 2007 American Institute of Physics

The persistent photoconductivity effect in AIGaN/GaN heterostructures grown on sapphire and SiC substrates

Cataloged from PDF version of article.In the present study, we reported the results of the investigation of electrical and optical measurements in Al(x)Ga(1-x)N/GaN heterostructures (x=0.20) that were grown by way of metal-organic chemical vapor deposition on sapphire and SiC substrates with the same buffer structures and similar conditions. We investigated the substrate material effects on the electrical and optical properties of Al(0.20)Ga(0.80)N/GaN heterostructures. The related electrical and optical properties of Al(x)Ga(1-x)N/GaN heterostructures were investigated by variable-temperature Hall effect measurements, photoluminescence (PL), photocurrent, and persistent photoconductivity (PPC) that in turn illuminated the samples with a blue (lambda=470 nm) light-emitting diode (LED) and thereby induced a persistent increase in the carrier density and two-dimensional electron gas (2DEG) electron mobility. In sample A (Al(0.20)Ga(0.80)N/GaN/sapphire), the carrier density increased from 7.59x10(12) to 9.9x10(12) cm(-2) via illumination at 30 K. On the other hand, in sample B (Al(0.20)Ga(0.80)N/GaN/SiC), the increments in the carrier density were larger than those in sample A, in which it increased from 7.62x10(12) to 1.23x10(13) cm(-2) at the same temperature. The 2DEG mobility increased from 1.22x10(4) to 1.37x10(4) cm(-2)/V s for samples A and B, in which 2DEG mobility increments occurred from 3.83x10(3) to 5.47x10(3) cm(-2)/V s at 30 K. The PL results show that the samples possessed a strong near-band-edge exciton luminescence line at around 3.44 and 3.43 eV for samples A and B, respectively. The samples showed a broad yellow band spreading from 1.80 to 2.60 eV with a peak maximum at 2.25 eV with a ratio of a near-band-edge excitation peak intensity up to a deep-level emission peak intensity ratio that were equal to 3 and 1.8 for samples A and B, respectively. Both of the samples that were illuminated with three different energy photon PPC decay behaviors can be well described by a stretched-exponential function and relaxation time constant tau as well as a decay exponent beta that changes with the substrate type. The energy barrier for the capture of electrons in the 2DEG channel via the deep-level impurities (DX-like centers) in AlGaN for the Al(0.20)Ga(0.80)N/GaN/sapphire and Al(0.20)Ga(0.80)N/GaN/SiC heterojunction samples are 343 and 228 meV, respectively. The activation energy for the thermal capture of an electron by the defects Delta E changed with the substrate materials. Our results show that the substrate material strongly affects the electrical and optical properties of Al(0.20)Ga(0.80)N/GaN heterostructures. These results can be explained with the differing degrees of the lattice mismatch between the grown layers and substrates. (C) 2008 American Institute of Physics

Double subband occupation of the two-dimensional electron gas in InxAl1− xN/AlN/ GaN/AlN heterostructures with a low indium content (0.064≤x≤0.140) barrier

Cataloged from PDF version of article.We present a carrier transport study on low indium content (0.064≤x≤0.140) InxAl1−xN/AlN/GaN/AlN heterostructures. Experimental Hall data were carried out as a function of temperature (33–300 K) and a magnetic field (0–1.4 T). A two-dimensional electron gas (2DEG) with single or double subbands and a twodimensional hole gas were extracted after implementing quantitative mobility spectrum analysis on the magnetic field dependent Hall data. The mobility of the lowest subband of 2DEG was found to be lower than the mobility of the second subband. This behavior is explained by way of interface related scattering mechanisms, and the results are supported with a one-dimensional self-consistent solution of non-linear Schrödinger–Poisson equations