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Sample records for inas-channel hemt kim

  1. Dae Hyun Kim

    Indian Academy of Sciences (India)

    Dae Hyun Kim. Articles written in Journal of Chemical Sciences. Volume 123 Issue 4 July 2011 pp 467-476. Palladium catalysed asymmetric alkylation of benzophenone Schiff base glycine esters in ionic liquids · Dae Hyun Kim Jin Kyu Im Dae Won Kim Minserk Cheong Hoon Sik Kim Deb Kumar Mukherjee · More Details ...

  2. Improved modeling on the RF behavior of InAs/AlSb HEMTs

    Science.gov (United States)

    Guan, He; Lv, Hongliang; Zhang, Yuming; Zhang, Yimen

    2015-12-01

    The leakage current and the impact ionization effect causes a drawback for the performance of InAs/AlSb HEMTs due to the InAs channel with a very narrow band gap of 0.35 eV. In this paper, the conventional HEMT small-signal model was enhanced to characterize the RF behavior for InAs/AlSb HEMTs. The additional gate leakage current induced by the impact ionization was modeled by adding two resistances RGh1 and RGh2 shunting the Cgs-Ri and Cgd-Rj branches, respectively, and the ionized-drain current was characterized by an additional resistance Rmi parallel with the output resistance Rds, meanwhile the influence of the impact ionization on the transconductance was modeled by an additional current source gmi controlled by Vgs. The additional inductance, evaluated as a function of f(ω, R), was introduced to characterize the frequency dependency of impact ionization by using the impact ionization effective rate 1/τi and a new frequency response rate factor n, which guaranteed the enhanced model reliable for a wide frequency range. As a result, the enhanced model achieved good agreement with the measurements of the S-parameters and Y-parameters for a wide frequency range, moreover, the simulated results of the stability factor K, the cutoff frequency fT, the maximum frequency of oscillation fmax, and the unilateral Mason's gain U were estimated to approach the experimental results with a high degree.

  3. Sung-Dai Kim

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. Sung-Dai Kim. Articles written in Bulletin of Materials Science. Volume 34 Issue 5 August 2011 pp 1059-1062. Cost-effective electrostatic-sprayed SrAl2O4:Eu phosphor coatings by using salted sol–gel derived solution · Kyu-Seog Hwang Bo-An Kang Sung-Dai Kim Seung ...

  4. Monte Carlo lattice program KIM

    International Nuclear Information System (INIS)

    Cupini, E.; De Matteis, A.; Simonini, R.

    1980-01-01

    The Monte Carlo program KIM solves the steady-state linear neutron transport equation for a fixed-source problem or, by successive fixed-source runs, for the eigenvalue problem, in a two-dimensional thermal reactor lattice. Fluxes and reaction rates are the main quantities computed by the program, from which power distribution and few-group averaged cross sections are derived. The simulation ranges from 10 MeV to zero and includes anisotropic and inelastic scattering in the fast energy region, the epithermal Doppler broadening of the resonances of some nuclides, and the thermalization phenomenon by taking into account the thermal velocity distribution of some molecules. Besides the well known combinatorial geometry, the program allows complex configurations to be represented by a discrete set of points, an approach greatly improving calculation speed

  5. Kim Dotcomi kättemaks / Andy Greenberg

    Index Scriptorium Estoniae

    Greenberg, Andy

    2013-01-01

    Skandaalne Internetimagnaat Kim Schmitz, rohkem tuntud kui Kim Dotcom, on veendunud, et tema loodud failivahetusprogrammi Megauploadi mahavõtmisega ja autoriõiguste rikkumise süüdistusega tehti talle liiga ning ta on asunud raevukalt vastulöögile USA valitsuse vastu

  6. Low Temperature Photoluminescence (PL) from High Electron Mobility Transistors (HEMTs)

    Science.gov (United States)

    2015-03-01

    aluminum gallium nitride (AlGaN)/gallium nitride (GaN) and indium aluminum nitride (InAlN)/GaN HEMT structures. These samples were cooled to 13 °K...SUBJECT TERMS Photoluminescence (PL), Laser Spectrscopy, High Electron Mobility Transistor (HEMT), aluminum gallium nitride (AlGaN), gallium nitride ...GaN), indium aluminum nitride (InAlN) 15. NUMBER OF PAGES 16 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT UNCLASSIFIED 18

  7. Projecting Pyongyang: The Future of North Korea's Kim Jong IL Regime

    National Research Council Canada - National Science Library

    Scobell, Andrew

    2008-01-01

    .... In this monograph, the focus is on the fate of the regime dominated by the Kim Dynasty, initially ruled by Kim Il Sung and then led by his son, Kim Jong Il, following the former's death in 1994...

  8. Failure Mechanisms for III-Nitride HEMT Devices

    Science.gov (United States)

    2013-11-19

    structural defects present in the latter consisted of a nickel- aluminum -gallium oxide. Observations of ultrathin-barrier AlN/GaN HEMTs grown on... aluminum -gallium oxide. b) Characterization of ultrathin-barrier AlN/GaN HEMTs on freestanding GaN substrates (work in collaboration with D.F. Storm and...barrier AlN/GaN high electron mobility transistor structures which were grown by rf-plasma MBE on freestanding, Ga-polar, hydride vapor phase epitaxy

  9. Coenite seiklused ja Kim Ki-duki huumor / Merit Kask

    Index Scriptorium Estoniae

    Kask, Merit

    2007-01-01

    60-nda Cannes'i filmifestivali filme : Ethan ja Joel Coen'i "Pole maad vanadele meestele" ("No Country for Old Men" ; Ameerika Ühendriigid), Kim Ki-duki "Hingetõmme" ("Soom"/"Breath" ; Lõuna-Korea) ja Raphael Nadjari "Tehilim" (Prantsusmaa - Iisrael - Ameerika Ühendriigid)

  10. Prikljutshenija Koenov i jumor Kim Ki-duka / Merit Kask

    Index Scriptorium Estoniae

    Kask, Merit

    2007-01-01

    60-nda Cannes'i filmifestivali filme : Ethan ja Joel Coen'i "Pole maad vanadele meestele" ("No Country for Old Men" ; Ameerika Ühendriigid), Kim Ki-duki "Hingetõmme" ("Soom"/"Breath" ; Lõuna-Korea) ja Raphael Nadjari "Tehilim" (Prantsusmaa - Iisrael - Ameerika Ühendriigid)

  11. Application of Hosaka and DJ Kim Whatmann paper protocols for ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-01

    Dec 1, 2009 ... Application of Hosaka and DJ Kim Whatmann paper protocols for rapid isolation of cowpea DNA. M. Yusuf1* S. Muranaka2, and A. A. Zaria1. 1Department of Plant Science, Faculty of Agriculture/Institue for Agricultural Research, Ahmadu Bello University, Zaria,. Nigeria. 2International Institute of Tropical ...

  12. An accurate and simple large signal model of HEMT

    DEFF Research Database (Denmark)

    Liu, Qing

    1989-01-01

    A large-signal model of discrete HEMTs (high-electron-mobility transistors) has been developed. It is simple and suitable for SPICE simulation of hybrid digital ICs. The model parameters are extracted by using computer programs and data provided by the manufacturer. Based on this model, a hybrid...

  13. OpenKIM - Building a Knowledgebase of Interatomic Models

    Science.gov (United States)

    Bierbaum, Matthew; Tadmor, Ellad; Elliott, Ryan; Wennblom, Trevor; Alemi, Alexander; Chen, Yan-Jiun; Karls, Daniel; Ludvik, Adam; Sethna, James

    2014-03-01

    The Knowledgebase of Interatomic Models (KIM) is an effort by the computational materials community to provide a standard interface for the development, characterization, and use of interatomic potentials. The KIM project has developed an API between simulation codes and interatomic models written in several different languages including C, Fortran, and Python. This interface is already supported in popular simulation environments such as LAMMPS and ASE, giving quick access to over a hundred compatible potentials that have been contributed so far. To compare and characterize models, we have developed a computational processing pipeline which automatically runs a series of tests for each model in the system, such as phonon dispersion relations and elastic constant calculations. To view the data from these tests, we created a rich set of interactive visualization tools located online. Finally, we created a Web repository to store and share these potentials, tests, and visualizations which can be found at https://openkim.org along with futher information.

  14. Anmeldelse af Kim Wind Andersen: Overblik over selskabers underskudsfremførsel

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2011-01-01

    Artiklen anmelder Kim Wind Andersen: Overblik over selskabers underskudsfremførsel (Thomson Reuters Professional, 2010)......Artiklen anmelder Kim Wind Andersen: Overblik over selskabers underskudsfremførsel (Thomson Reuters Professional, 2010)...

  15. Chang Sei Kim's Activities on Public Health in Colonial Korea

    Directory of Open Access Journals (Sweden)

    Park Yunjae

    2006-12-01

    Full Text Available After graduating from Severance Medical College in 1916, Chang Sei Kim went to Shanghai to work as a missionary in a adventist hospital. The establishment of the Korean Provisional Government led him to participate in the independence movement. Educating nurses to assist the forthcoming war for independence, he seemed to realize the fact that the health of Koreans would be a key factor for achieving independence. He left for the U.S. to conduct comprehensive research on medicine. Chang Sei Kim was the first Korean to receive a Ph. D. degree of Public Health, graduating from the Johns Hopkins School of Hygiene and Public Health in 1925. He then gained an opportunity to work for Korea as a professor at Severance Medical College. His objective was the 'Reconstruction of the Korean People In Terms of Physical Constitution.' He pointed out that Koreans' weak state of health was a major reason for Korea's colonization. To gain independence, he emphasized that the Korean people should receive education on public health in order to improve the primitive conditions of sanitation. There is little doubt that Chang Sei Kim's ideas developed Heungsadan's views on medicine in terms of its stress on cultivation of ability, especially considering the fact that he was a member of the organization. As a member of the colonized who could not participate in the developing official policy, Chang Sei Kim was not able to implement his ideas fully, because an individual or a private organization could not carry out policy on public health as large a scale as the government did. Never giving up his hopes for Korean independence, he rejected requests to assume official posts in the Government-General. That was why he was particularly interested in the Self-Governing Movement in 1920s Korea. If the movement had attained its goal, he might have worked for the enhancement of sanitary environment as a director of Sanitary Department. His application for funding to establish

  16. Tubular kidney injury molecule-1 (KIM-1) in human renal disease

    NARCIS (Netherlands)

    van Timmeren, M. M.; van den Heuvel, Marius C.; Bailly, V.; Bakker, S. J. L.; van Goor, H.; Stegeman, C. A.

    KIM-1, a transmembrane tubular protein with unknown function, is undetectable in normal kidneys, but is markedly induced in experimental renal injury. The KIM-1 ectodomain is cleaved, detectable in urine, and reflects renal damage. KIM-1 expression in human renal biopsies and its correlation with

  17. Unstable behaviour of normally-off GaN E-HEMT under short-circuit

    Science.gov (United States)

    Martínez, P. J.; Maset, E.; Sanchis-Kilders, E.; Esteve, V.; Jordán, J.; Bta Ejea, J.; Ferreres, A.

    2018-04-01

    The short-circuit capability of power switching devices plays an important role in fault detection and the protection of power circuits. In this work, an experimental study on the short-circuit (SC) capability of commercial 600 V Gallium Nitride enhancement-mode high-electron-mobility transistors (E-HEMT) is presented. A different failure mechanism has been identified for commercial p-doped GaN gate (p-GaN) HEMT and metal-insulator-semiconductor (MIS) HEMT. In addition to the well known thermal breakdown, a premature breakdown is shown on both GaN HEMTs, triggered by hot electron trapping at the surface, which demonstrates that current commercial GaN HEMTs has requirements for improving their SC ruggedness.

  18. Sexualidad violenta en el cine de Kim Ki-duk

    Directory of Open Access Journals (Sweden)

    Daniel Muñoz Ruiz

    2011-07-01

    Full Text Available En sus más de 110 años de vida el cine ha representado la sexualidad humana en todas sus modalidades y desde los más variados puntos de vista. El cine de Kim Ki-duk ha sorprendido y escandalizado al público por su crudeza y, a veces, excesiva violencia. El director surcoreano ha explorado a lo largo de su filmografía el tema del sexo siempre desde puntos de vista dramáticos y hasta truculentos. En sus películas la mayoría de las relaciones sexuales carecen de amor y afecto. Nunca son placenteras. La violación, la prostitución, la violencia de género y las frustraciones sexuales son temas recurrentes en su cine.

  19. Materialismo percettivo. Da Democrito a Lenin, da Hobbes a Kim

    Directory of Open Access Journals (Sweden)

    Michele Gardini

    2012-05-01

    Full Text Available The paper tries to outline something like a short “critique of pure materialism” in the domain of perception, a sketch showing – through a series of examples, picked out in an apparently heterogeneous fashion from the Western philosophical tradition – how this epistemological model each time, and in everyone of its forms, fails in giving account of the basic features of perceiving.  After giving a survey of authors like Democritus, Hobbes, De Sade, Lenin, the final appendix, devoted to the concept of “supervenience” and its treatment in Davidson and Kim, aims at summarizing the whole problem through the categories of the contemporary philosophy of mind. The conclusion is that a pure materialistic approach is incapable to give reason to some of the fundamental characteristics of perception, that make it one of the basic moods of “being-in-the-world”.

  20. Global Policing and the Case of Kim Dotcom

    Directory of Open Access Journals (Sweden)

    Darren Palmer

    2013-11-01

    Full Text Available In early 2012, 76 heavily armed police conducted a raid on a house in Auckland, New Zealand. The targets were Kim Dotcom, a German national with a NZ residency visa, and several colleagues affiliated with Megaupload, an online subscription-based peer-to-peer (P2P file sharing facility. The alleged offences involved facilitating unlawful file sharing and United States federal criminal copyright violations. Following the raid, several court cases provide valuable insights into emerging ‘global policing’ practices (Bowling and Sheptycki 2012 based on communications between sovereign enforcement agencies.  This article uses these cases to explore the growth of ‘extraterritorial’ police powers that operate ‘across borders’ (Nadelmann 1993 as part of several broader transformations of global policing in the digital age.

  1. Temperature Dependence of GaN HEMT Small Signal Parameters

    OpenAIRE

    Ali M. Darwish; Amr A. Ibrahim; H. Alfred Hung

    2011-01-01

    This study presents the temperature dependence of small signal parameters of GaN/SiC HEMTs across the 0–150°C range. The changes with temperature for transconductance ( m ), output impedance ( d s and d s ), feedback capacitance ( d g ), input capacitance ( g s ), and gate resistance ( g ) are measured. The variations with temperature are established for m , d s , d s , d g , g s , and g in the GaN technology. This information is useful for MMIC designs....

  2. Development of Submillimeter SIS Mixers and Broadband HEMT Amplifiers

    Science.gov (United States)

    Zmuidzinas, J.

    2004-01-01

    This is the final technical report for NASA grant NAG5-9493. entitled "Development of Submillimeter SIS Mixers and Broadband HEMT Amplifiers". The goal of this project was to develop and demonstrate a new generation of superconducting tunnel junction (SIS) receivers with extremely wide instantaneous (intermediate-frequency, or IF) bandwidths. of order 12 GHz. along with the wideband low-noise microwave HEMT (high electron mobility transistor) amplifiers which follow the SIS mixer. These wideband SIS/HEMT receivers would allow rapid submillimeter wavelength spectral line surveys to be carried out, for instance with the NASA airborne observatory SOFIA. and could potentially be useful for future submillimeter space missions such as SAFIR. In addition, there are potential NASA earth science applications. such as the monitoring of the distribution of chemical species in the stratosphere and troposphere using the limb-sounding technique. The overall goals of this project have been achieved: a broadband 200-300 SIS receiver was designed and constructed, and was demonstrated in the field through a test run at the Caltech Submillimeter Observatory on Mauna Kea. HI. The technical details are described in the appendices. which are primarily conference publications. but Appendix A also includes an unpublished summary of the latest results. The work on the SIS mixer design are described in the conference publications (appendices B and C). The "Supermix" software package that was developed at Caltech and used for the SIS design is also described in two conference papers, but has been substantially revised, debugged. and extended as part of the work completed for this grant. The Supermix package is made available to the community at no charge. The electromagnetic design of a radial waveguide probe similar to the one used in this work is described in a journal publication. Details of the novel fabrication procedure used for producing the SIS devices at JPL are also given in an

  3. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    DEFF Research Database (Denmark)

    Gurpinar, Emre; Iannuzzo, Francesco; Yang, Yongheng

    2018-01-01

    In this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices...... are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a four-layer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained...

  4. Lessons learned from 15 years of KIMS and 5 years of ACROSTUDY

    DEFF Research Database (Denmark)

    Luger, Anton; Feldt-Rasmussen, Ulla; Abs, Roger

    2011-01-01

    and effectiveness of growth hormone (GH) therapy in GH-deficient children since its inception in 1987. Following closely in the footsteps of KIGS is KIMS (Pfizer International Metabolic Database). As of 2009, KIMS has been collecting data on the long-term safety and clinical outcomes of GH replacement in GH......, pharmacoepidemiological surveys such as KIMS and ACROSTUDY provide valuable information on the safety and effectiveness of treatment with GH replacement and pegvisomant in the real world....

  5. Magnetic flux creep in HTSC and Anderson-Kim theory

    International Nuclear Information System (INIS)

    Lykov, A.N.

    2014-01-01

    The theoretical and experimental data on flux creep in high-temperature superconductors (HTSC) were analyzed in the review paper. On the one hand, the main attention is paid to the most striking experimental results which have had a significant influence on the investigations of flux creep in HTSC. On the other hand, the analysis of theoretical studies is concentrated on the works, which explain the features of flux creep on the basis of the Anderson-Kim (AK) theory modifications, and received previously unsufficient attention. However, it turned out that the modified AK theory could explain a lot of features of flux creep in HTSC: the scaling behaviour of current-voltage curves of HTSC, the finite rate of flux creep at ultra low temperatures, the logarithmic dependence of effective pinning potential as a function of transport current and its decrease with temperature. The harmonic potential field which is used in this approach makes it possible to solve accurately the both problems: viscous vortex motion and flux creep in this field. Moreover the distribution of pinning potential and the interaction of vortices with each other are taken into account in the approach. Thus, the modification of the AK theory consists, essentially, in its detailed elaboration and approaching to real situations in superconductors

  6. Effect of Passivation on Microwave Power Performances of AlGaN/GaN/Si HEMTs

    Directory of Open Access Journals (Sweden)

    H. MOSBAHI

    2014-05-01

    Full Text Available This paper reports on the use of plasma assisted molecular beam epitaxy of AlGaN/GaN high electron mobility transistors (HEMTs grown on silicon substrate. Surface passivation effects on AlGaN/GaN HEMTs were studied using SiO2/SiN dielectric layers grown by plasma enhanced chemical vapor deposition. The direct current measurement, pulsed characteristics and microwave small-signal characteristics were studied before and after passivation. An improvement of drain-source current density and the extrinsic transconductance was observed on the passivated HEMTs when compared with the unpassivated HEMTs. An enhancement of cut-off frequency (ft and maximum power gain (fmax was also observed for the devices with full SiO2/SiN passivation. A good correlation is found between pulsed and power measurements.

  7. A STUDY OF MICROBES IN FRUIT JUICES, KIMS-AMALAPURAM

    Directory of Open Access Journals (Sweden)

    Nagaraja

    2015-12-01

    Full Text Available INTRODUCTION Fruit and sugarcane juices are nutritious drinks with great taste and health benefits. Food borne illnesses associated with consumption of Fruit and sugarcane juices at several places in India and elsewhere. Fruit juices were served with added ice pieces. Hygienic standards are not maintained while transporting from the field to the place of extraction and preparation. Hence a rapid review of the fruit juices from street vendors has been undertaken along with sugarcane juice. Raw sugarcane juice is a refreshing juice in many parts of Andhra Pradesh. The present study is to assess the prevalence of different organisms from different fruit juices collected from street vendors. METHODS Fruit juices are collected namely sugarcane, sweet lemon, orange, grape apple, pineapple pomegranate. A total 100 samples of fruit juices were collected from road side from different vendors. 150 ml of each variety of fruit juices were collected from different vendors in screw capped bottles and subjected to microbial analysis, processed with in 30mts in the department of microbiology at KIMS by standard methods. RESULTS The analysed samples of fruit juices are found to be contaminated with different bacteria, Escherichia coli 30% Klebsiella pneumoniae 10% Staphylococcus aureus 20% Enterococcus faecalis 04% Pseudomonas aeruginosa 10% ASB 04% (aerobic spore bearers Micrococci 02% Proteus 20% Salmonella. Shigella and Vibrios were not isolated. CONCLUSION It is high time that street vendors should have health education by volunteers, health workers from PHC (primary health centers and people well versed with community medicine practice for implementation of standard hygienic protocols may reduce contamination of fruit and sugarcane juices The concerned health authorities need to ensure and insist to follow the protocols by the vendors and license holders to the vendors.

  8. Complete Genome Sequence of Lactobacillus curvatus Strain WiKim38 Isolated from Kimchi

    Science.gov (United States)

    Lee, Se Hee; Jung, Min Young; Song, Jung-Hee; Lee, Moeun

    2017-01-01

    ABSTRACT Lactobacillus curvatus WiKim38 is a potential probiotic strain isolated from kimchi, a traditional Korean fermented food. The complete genome of the WiKim38 strain consisted of a circular chromosome of 1,940,170 bp in length with a G+C content of 41.93%. PMID:28473381

  9. High-Speed Gate Driver Using GaN HEMTs for 20-MHz Hard Switching of SiC MOSFETs

    OpenAIRE

    Okuda, Takafumi; Hikihara, Takashi

    2017-01-01

    In this paper, we investigated a gate driver using a GaN HEMT push-pull configuration for the high-frequency hard switching of a SiC power MOSFET. Low on-resistance and low input capacitance of GaN HEMTs are suitable for a high-frequency gate driver from the logic level, and robustness of SiC MOSFET with high avalanche capability is suitable for a valve transistor in power converters. Our proposed gate driver consists of digital isolators, complementary Si MOSFETs, and GaN HEMTs. The GaN HEMT...

  10. REPRESENTATION OF KIM JONG-UN’S SUCCESSION IN BBC NEWS: A CRITICAL DISCOURSE ANALYSIS

    Directory of Open Access Journals (Sweden)

    Hendra Nugraha

    2016-04-01

    Full Text Available This research attempts to reveal representation of Kim Jong-Un’s succession in BBC News through textual and discursive practice analysis. The data of this thesis are taken from BBC News website on 29 and 31 December 2011. The theory applied to seek the objective of the research is Critical Discourse Analysis developed by Fairclough. Through textual and discursive practice analysis, the writer finds pthat BBC employs more passive material clauses than active material clauses in depicting Kim Jong-Un’s succession. BBC also represents Kim Jong-Un’s succession as premature process where Kim Jong-Un is portrayed as a young and inexperienced leader. Besides the prematurity of the succession, the present writer finds that BBC represents Kim Jong-Un’s succession as continuity of Kim’s family dynasty. Thus, the succession is based on his resemblance to Kim Il-Sung, the founder of Democratic People’s Republic of Korea, rather than Kim Jong-Un ability and competency.

  11. Reverse blocking characteristics and mechanisms in Schottky-drain AlGaN/GaN HEMT with a drain field plate and floating field plates

    International Nuclear Information System (INIS)

    Mao Wei; She Wei-Bo; Zhang Jin-Feng; Zheng Xue-Feng; Wang Chong; Hao Yue; Yang Cui

    2016-01-01

    In this paper, a novel AlGaN/GaN HEMT with a Schottky drain and a compound field plate (SD-CFP HEMT) is presented for the purpose of better reverse blocking capability. The compound field plate (CFP) consists of a drain field plate (DFP) and several floating field plates (FFPs). The physical mechanisms of the CFP to improve the reverse breakdown voltage and to modulate the distributions of channel electric field and potential are investigated by two-dimensional numerical simulations with Silvaco-ATLAS. Compared with the HEMT with a Schottky drain (SD HEMT) and the HEMT with a Schottky drain and a DFP (SD-FP HEMT), the superiorities of SD-CFP HEMT lie in the continuous improvement of the reverse breakdown voltage by increasing the number of FFPs and in the same fabrication procedure as the SD-FP HEMT. Two useful optimization laws for the SD-CFP HEMTs are found and extracted from simulation results. The relationship between the number of the FFPs and the reverse breakdown voltage as well as the FP efficiency in SD-CFP HEMTs are discussed. The results in this paper demonstrate a great potential of CFP for enhancing the reverse blocking ability in AlGaN/GaN HEMT and may be of great value and significance in the design and actual manufacture of SD-CFP HEMTs. (paper)

  12. Reverse blocking characteristics and mechanisms in Schottky-drain AlGaN/GaN HEMT with a drain field plate and floating field plates

    Science.gov (United States)

    Wei, Mao; Wei-Bo, She; Cui, Yang; Jin-Feng, Zhang; Xue-Feng, Zheng; Chong, Wang; Yue, Hao

    2016-01-01

    In this paper, a novel AlGaN/GaN HEMT with a Schottky drain and a compound field plate (SD-CFP HEMT) is presented for the purpose of better reverse blocking capability. The compound field plate (CFP) consists of a drain field plate (DFP) and several floating field plates (FFPs). The physical mechanisms of the CFP to improve the reverse breakdown voltage and to modulate the distributions of channel electric field and potential are investigated by two-dimensional numerical simulations with Silvaco-ATLAS. Compared with the HEMT with a Schottky drain (SD HEMT) and the HEMT with a Schottky drain and a DFP (SD-FP HEMT), the superiorities of SD-CFP HEMT lie in the continuous improvement of the reverse breakdown voltage by increasing the number of FFPs and in the same fabrication procedure as the SD-FP HEMT. Two useful optimization laws for the SD-CFP HEMTs are found and extracted from simulation results. The relationship between the number of the FFPs and the reverse breakdown voltage as well as the FP efficiency in SD-CFP HEMTs are discussed. The results in this paper demonstrate a great potential of CFP for enhancing the reverse blocking ability in AlGaN/GaN HEMT and may be of great value and significance in the design and actual manufacture of SD-CFP HEMTs. Project supported by the National Natural Science Foundation of China (Grant Nos. 61204085, 61334002, 61306017, 61474091, 61574112, and 61574110).

  13. AlGaN/GaN-based HEMTs for electrical stimulation of neuronal cell cultures

    International Nuclear Information System (INIS)

    Witte, H; Warnke, C; Krost, A; Voigt, T; De Lima, A; Ivanov, I; Vidakovic-Koch, T R; Sundmacher, K

    2011-01-01

    Unipolar source-drain voltage pulses of GaN/AlGaN-high electron mobility transistors (HEMTs) were used for stimulation of cultured neuronal networks obtained from embryonic rat cerebral cortex. The HEMT sensor was grown by metal organic vapour phase epitaxy on a 2 inch sapphire substrate consisting of 10 single HEMTs concentrically arranged around the wafer centre. Electrolytic reactions between the HEMT sensor surface and the culture medium were not detected using cyclic voltammetry. During voltage pulses and resulting neuronal excitation, capacitances were recharged giving indications of the contributions of the AlGaN and AlO x isolation layers between the two-dimensional electron gas channel and the neuron culture. The resulting threshold current for stimulation of neuron activity strongly depended on the culture and HEMT position on the sensor surface under consideration which was caused by different impedances of each neuron culture and position within the culture. The differences of culture impedances could be explained by variations of composition, thickness and conductivity of the culture areas.

  14. AlGaN/GaN-based HEMTs for electrical stimulation of neuronal cell cultures

    Science.gov (United States)

    Witte, H.; Warnke, C.; Voigt, T.; de Lima, A.; Ivanov, I.; Vidakovic-Koch, T. R.; Sundmacher, K.; Krost, A.

    2011-09-01

    Unipolar source-drain voltage pulses of GaN/AlGaN-high electron mobility transistors (HEMTs) were used for stimulation of cultured neuronal networks obtained from embryonic rat cerebral cortex. The HEMT sensor was grown by metal organic vapour phase epitaxy on a 2 inch sapphire substrate consisting of 10 single HEMTs concentrically arranged around the wafer centre. Electrolytic reactions between the HEMT sensor surface and the culture medium were not detected using cyclic voltammetry. During voltage pulses and resulting neuronal excitation, capacitances were recharged giving indications of the contributions of the AlGaN and AlOx isolation layers between the two-dimensional electron gas channel and the neuron culture. The resulting threshold current for stimulation of neuron activity strongly depended on the culture and HEMT position on the sensor surface under consideration which was caused by different impedances of each neuron culture and position within the culture. The differences of culture impedances could be explained by variations of composition, thickness and conductivity of the culture areas.

  15. Reliability-Driven Assessment of GaN HEMTs and Si IGBTs in 3L-ANPC PV Inverters

    DEFF Research Database (Denmark)

    Gurpinar, Emre; Yang, Yongheng; Iannuzzo, Francesco

    2016-01-01

    In this paper, thermal loading of the state-of-the-art GaN HEMTs and traditional Si IGBTs in 3L-ANPC PV inverters is presented considering real-field long-term mission profiles (i.e., ambient temperature and solar irradiance). A comparison of Si IGBT against GaN HEMT with three different possibil...

  16. Novel attributes of AlGaN/AlN/GaN/SiC HEMTs with the multiple indented channel

    Science.gov (United States)

    Orouji, Ali A.; Ghaffari, Majid

    2015-11-01

    In this paper, a high performance AlGaN/AlN/GaN/SiC High Electron Mobility Transistor (HEMT) with the multiple indented channel (MIC-HEMT) is proposed. The main focus of the proposed structure is based on reduction of the space around the gate, stop of the spread of the depletion region around the source-drain, and decrement of the thickness of the channel between the gate and drain. Therefore, the breakdown voltage increases, meanwhile the elimination of the gate depletion layer extension to source/drain decreases the gate-source and gate-drain capacitances. The optimized results reveal that the breakdown voltage and the drain saturation current increase about 178% and 46% compared with a conventional HEMT (C-HEMT), respectively. Therefore, the maximum output power density is improved by factor 4.1 in comparison with conventional one. Also, the cut-off frequency of 25.2 GHz and the maximum oscillation frequency of 92.1 GHz for the MIC-HEMT are obtained compared to 13 GHz and 43 GHz for that of the C-HEMT and the minimum figure noise decreased consequently of reducing the gate-drain and gate-source capacitances by about 42% and 40%, respectively. The proposed MIC-HEMT shows a maximum stable gain (MSG) exceeding 24.1 dB at 3.1 GHz which the greatest gain is yet reported for HEMTs, showing the potential of this device for high power RF applications.

  17. Algan/Gan Hemt By Magnetron Sputtering System

    Science.gov (United States)

    Garcia Perez, Roman

    In this thesis, the growth of the semiconductor materials AlGaN and GaN is achieved by magnetron sputtering for the fabrication of High Electron Mobility Transistors (HEMTs). The study of the deposited nitrides is conducted by spectroscopy, diffraction, and submicron scale microscope methods. The preparation of the materials is performed using different parameters in terms of power, pressure, temperature, gas, and time. Silicon (Si) and Sapphire (Al2O3) wafers are used as substrates. The chemical composition and surface topography of the samples are analyzed to calculate the materials atomic percentages and to observe the devices surface. The instruments used for the semiconductors characterization are X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscope (AFM). The project focused its attention on the reduction of impurities during the deposition, the controlled thicknesses of the thin-films, the atomic configuration of the alloy AlxGa1-xN, and the uniformity of the surfaces.

  18. Behind their eyes : identity in the work of Li-Young Lee and Suji Kwock Kim

    OpenAIRE

    Hand, Meadhbh

    2014-01-01

    The introduction to this study outlines the theoretical framework for comparing the work of Li-Young Lee and Suji Kwock Kim. Using Walter Mignolo's theories about "border thinking," which he outlined in Local Histories/Global Designs, alongside Anzaldua's Borderlands/La Frontera as a basis for approaching Kim's and Lee's work, I demonstrate how the poets may be considered as embodying the role of border thinkers. Marianne Hirsch's definition of "postmemory," is explored, and its relevance to ...

  19. North Korea’s Provocation and Escalation Calculus: Dealing with the Kim Jong-un Regime

    Science.gov (United States)

    2015-08-01

    Select a caveat Unlimited distribution North Korea’s Provocation and Escalation Calculus: Dealing with the Kim Jong-un Regime Ken E...with bold strokes that included closing down the Kaesong Industrial Complex , a joint venture of North and South Korea, and threatening to launch...took ampules of cyanide hidden in cigarettes. The male agent died, but the female agent, Kim Hyon- hui, survived and later confessed to the bombing

  20. Study of interface state trap density on characteristics of MOS-HEMT

    Science.gov (United States)

    Tseng, Ming-Chun; Hung, Ming-Hsien; Wuu, Dong-Sing; Horng, Ray-Hua

    2015-03-01

    In this study, the effects of chemical treatment on the properties of MOS capacitors and metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) were studied. The structure consist of Al2O3/u-GaN/AlN buffer/ Si substrate and Al2O3 (10 nm)/u-AlGaN (25 nm)/u-GaN (2μm)/AlN buffer/Si substrate for MOS capacitor and MOS-HEMT device, respectively. There are four chemical treatment recipes, which consist of organic solvents, oxygen plasma, BCl3 plasma, dilute acidic solvent, hydrofluoric acid and RCA-like clean process to remove the metal ions, organic contamination and native oxide. Four different chemical treatment recipes treated the surface of u-GaN before Al2O3 was grown on the treated surface to reduce the interface state trap densities (Dit). The Dit value was calculated from measurement of C-V curve with 1M Hz frequency. The formation of interface state trap of u-GaN surface is modified by different chemical solution of varied chemical treatment recipe, which further influence the breakdown voltage (Vbk), on-resistance (Ron), threshold voltage (Vth) and drain current (Id) of MOS-HEMT. The Vth of MOS-HEMT with organic solvents clean treatment is -11.00V. The MOS-HEMT after BCl3 plasma and organic solvents clean treatment shows the lowest Vth of -9.55V. The electronic characteristics of MOS HEMT device with four different chemical treatment recipes were investigated in this article.

  1. The sensitivity research of multiparameter biosensors based on HEMT by the mathematic modeling method

    Science.gov (United States)

    Tikhomirov, V. G.; Gudkov, A. G.; Agasieva, S. V.; Gorlacheva, E. N.; Shashurin, V. D.; Zybin, A. A.; Evseenkov, A. S.; Parnes, Y. M.

    2017-11-01

    The numerical impact modeling of some external effects on the CVC of biosensors based on AlGaN/GaN heterostructures (HEMT) was carried out. The mathematical model was created that allowed to predict the behavior of the drain current depending on condition changes on the heterostructure surface in the gate region and to start the process of directed construction optimization of the biosensors based on AlGaN/GaN HEMT with the aim of improving their performance. The calculation of the drain current of the biosensor construction was carried out to confirm the reliability of the developed mathematical model and obtained results.

  2. Terahertz amplification in RTD-gated HEMTs with a grating-gate wave coupling topology

    Energy Technology Data Exchange (ETDEWEB)

    Condori Quispe, Hugo O.; Sensale-Rodriguez, Berardi [The University of Utah, Salt Lake City, Utah 84112 (United States); Encomendero-Risco, Jimy J.; Xing, Huili Grace [University of Notre Dame, Notre Dame, Indiana 46556 (United States); Cornell University, Ithaca, New York 14853 (United States)

    2016-08-08

    We theoretically analyze the operation of a terahertz amplifier consisting of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT) in a grating-gate topology. In these devices, the key element enabling substantial power gain is the efficient coupling of terahertz waves into and out of plasmons in the RTD-gated HEMT channel, i.e., the gain medium, via the grating-gate itself, part of the active device, rather than by an external antenna structure as discussed in previous works, therefore potentially enabling terahertz amplification with associated power gains >40 dB.

  3. Is Urinary KIM-1 a Predictor of EGFR Decline, Incident Cardiovascular Disease, and All Cause Mortality?

    DEFF Research Database (Denmark)

    Eickhoff, Mie Klessen; von Scholten, Bernt Johan; Reinhard, Henrik

    Background Urinary levels of kidney injury molecule 1 (KIM-1) has shown to reflect tubular pathophysiology. We evaluated KIM-1 as a predictor of decline in estimated glomerular filtration rate (eGFR), incident cardiovascular disease (CVD) and all-cause mortality in patients with type 2 diabetes (T2......D) and microalbuminuria without clinical coronary artery disease. Methods We performed a prospective study including 200 patients, all receiving multifactorial treatment. Urinary KIM-1 was measured at baseline and was available in 191 patients. Adjusted Cox models included sex, age, LDL cholesterol...... the predefined CKD progression endpoint after 4.9 years (median). Higher urinary KIM-1 was a predictor of eGFR decline, unadjusted HR (95% CI): 1.9 (1.2-2.8); p=0.003, and in the adjusted model HR 1.7 (1.0-2.7); p=0.034. For CVD events urinary KIM-1 was a determinant in the unadjusted model (HR 1.4 (1.0-2.1); p...

  4. A new small-signal modeling and extraction method in AlGaN/GaN HEMTs

    Science.gov (United States)

    Lu, Jing; Wang, Yan; Ma, Long; Yu, Zhiping

    2008-01-01

    In this paper, a new 20-element small-signal equivalent circuit for GaN HEMTs is proposed and correspondingly, a direct extraction method is developed. Compared with the 16-element conventional GaAs-based HEMT small-signal model (SSM), two parasitic distributed inter-electrode extrinsic capacitances and two additional feedback intrinsic resistances are considered. The new modeling approach for GaN HEMTs is verified by comparing the simulated small-signal S-parameter with the measured data over wide frequency and bias ranges.

  5. Recessed insulator and barrier AlGaN/GaN HEMT: A novel structure ...

    Indian Academy of Sciences (India)

    In this study, a gallium nitride (GaN) high electron mobility transistor (HEMT) with recessed insulator and barrier is reported. In the proposed structure, insulator is recessed into the barrier at the drain side and barrier is recessed into the buffer layer at the source side. We study important device characteristics such as electric ...

  6. AlGaN/GaN-based HEMT on SiC substrate for microwave ...

    Indian Academy of Sciences (India)

    (HEMT) on SiC substrate is proposed and its DC as well as microwave characteristics are dis- cussed for Si3N4 and ... From DC characteristics, the saturation drain currents are measured to be 600 mA/mm and. 550 mA/mm for ..... figure 12 from a family of Mason's unilateral gain (MUG) curves for both passivated devices.

  7. Recessed insulator and barrier AlGaN/GaN HEMT

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 88; Issue 4. Recessed insulator and barrier AlGaN/GaN HEMT: A novel structure for improving DC and RF characteristics ... Keywords. AlGaN/GaN high electron mobility transistor; breakdown voltage; output power density; short channel effect; gate-drain capacitance ...

  8. Enhanced lateral heat dissipation packaging structure for GaN HEMTs on Si substrate

    International Nuclear Information System (INIS)

    Cheng, Stone; Chou, Po-Chien; Chieng, Wei-Hua; Chang, E.Y.

    2013-01-01

    This work presents a technology for packaging AlGaN/GaN high electron mobility transistors (HEMTs) on a Si substrate. The GaN HEMTs are attached to a V-groove copper base and mounted on a TO-3P leadframe. The various thermal paths from the GaN gate junction to the case are carried out for heat dissipation by spreading to protective coating; transferring through the bond wires; spreading in the lateral device structure through the adhesive layer, and vertical heat spreading of silicon chip bottom. Thermal characterization showed a thermal resistance of 13.72 °C/W from the device to the TO-3P package. Experimental tests of a 30 mm gate-periphery single chip packaged in a 5 × 3 mm V-groove Cu base with a 100 V drain bias showed power dissipation of 22 W. -- Highlights: ► An enhanced packaging structure designed for AlGaN/GaN HEMTs on an Si substrate. ► The V-groove copper base is designed on the device periphery surface heat conduction for enhancing Si substrate thermal dissipation. ► The proposed device shows a lower thermal resistance and upgrade in thermal conductivity capability. ► This work provides useful thermal IR imagery information to aid in designing high efficiency package for GaN HEMTs on Si

  9. Conversion Matrix Analysis of GaAs HEMT Active Gilbert Cell Mixers

    DEFF Research Database (Denmark)

    Jiang, Chenhui; Johansen, Tom Keinicke; Krozer, Viktor

    2006-01-01

    In this paper, the nonlinear model of the GaAs HEMT active Gilbert cell mixer is investigated. Based on the model, the conversion gain expression of active Gilbert cell mixers is derived theoretically by using conversion matrix analysis method. The expression is verified by harmonic balance...

  10. Wideband Monolithic Microwave Integrated Circuit Frequency Converters with GaAs mHEMT Technology

    DEFF Research Database (Denmark)

    Krozer, Viktor; Johansen, Tom Keinicke; Djurhuus, Torsten

    2005-01-01

    We present monolithic microwave integrated circuit (MMIC) frequency converter, which can be used for up and down conversion, due to the large RF and IF port bandwidth. The MMIC converters are based on commercially available GaAs mHEMT technology and are comprised of a Gilbert mixer cell core...

  11. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    Energy Technology Data Exchange (ETDEWEB)

    Gurpinar, Emre [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Power Electronics and Electric Machinery Research Group; Iannuzzo, Francesco [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology; Yang, Yongheng [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology; Castellazzi, Alberto [Univ. of Nottingham (United Kingdom). Power Electronics, Machines and Control (PEMC); Blaabjerg, Frede [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology

    2017-11-23

    Here in this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a fourlayer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained. The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L-ANPC with the output power of up to 1 kW are presented, which verifies the performance of the proposed design in terms of ultra-low inductance.

  12. AlGaN/GaN-based HEMT on SiC substrate for microwave ...

    Indian Academy of Sciences (India)

    The AlGaN/GaN-based high electron mobility transistors (HEMTs) are attracting much research interest worldwide because of their high density of states (DOS), high elec- tron saturation drift velocity, large band gap, high breakdown voltage, high electric field. DOI: 10.1007/s12043-012-0290-9; ePublication: 20 June 2012.

  13. C-V characterization of Schottky- and MIS-gate SiGe/Si HEMT structures

    International Nuclear Information System (INIS)

    Onojima, Norio; Kasamatsu, Akihumi; Hirose, Nobumitsu; Mimura, Takashi; Matsui, Toshiaki

    2008-01-01

    Electrical properties of Schottky- and metal-insulator-semiconductor (MIS)-gate SiGe/Si high electron mobility transistors (HEMTs) were investigated with capacitance-voltage (C-V) measurements. The MIS-gate HEMT structure was fabricated using a SiN gate insulator formed by catalytic chemical vapor deposition (Cat-CVD). The Cat-CVD SiN thin film (5 nm) was found to be an effective gate insulator with good gate controllability and dielectric properties. We previously investigated device characteristics of sub-100-nm-gate-length Schottky- and MIS-gate HEMTs, and reported that the MIS-gate device had larger maximum drain current density and transconductance (g m ) than the Schottky-gate device. The radio frequency (RF) measurement of the MIS-gate device, however, showed a relatively lower current gain cutoff frequency f T compared with that of the Schottky-gate device. In this study, C-V characterization of the MIS-gate HEMT structure demonstrated that two electron transport channels existed, one at the SiGe/Si buried channel and the other at the SiN/Si surface channel

  14. Bridging communication between public and government: a case study on kim surabaya

    Science.gov (United States)

    Aji, G. G.; Tsuroyya; Dewi, P. A. R.

    2018-01-01

    In democratic era, the public communication paradigm has shifted from a one-way socialization to more interactive one. As a consequence of freedom of speech, the public can Actively communicate with the government and vice versa. The problem is government is almost impossible to reach all public groups. Therefore, they has created the concept of social institutions as a communication hub between the government and its public, named the Kelompok Informasi Masyarakat (KIM). This research examines the activity of KIM in Surabaya on bridging public between government and the public. Using a case study approach, this research utilized various techniques of data collection such as: interviews, observation, and documentation. The results Showed that KIM plays a role in the two-way flow of information; to diseminate program and submit complaints and suggestions from the public about the policy. This study confirm the urgency of utilization on various channels in communicating with the public.

  15. [The medical treatment of Kim Phúc at the BG Unfallklinik Ludwigshafen].

    Science.gov (United States)

    Kiefer, J; Daigeler, A; Lehnhardt, M

    2012-08-01

    The Vietnam War was a military conflict in Vietnam during the Cold War that followed the First Indochina War. This war was fought between North Vietnam, supported by its communist allies, and the government of South Vietnam, supported by the USA and other anti-communist countries. Kim Phúc is the child depicted in the Pulitzer Prize winning photograph taken on June 8, 1972 by AP photographer Nick Út. The iconic photo shows her at about nine years of age running naked on a road amid the chaos after being severely burned by a napalm attack. After 14 months of hospital stay and 17 surgical procedures Kim Phúc was able to return home. Since then, she was used as a propaganda symbol by the communist government of Vietnam. To continue her studies, Kim was granted permission to move to Cuba where she met her future husband. However, the sequelae of her burn wounds affected her everyday life enormously. In 1984, with the support of the international aid organization "terre des hommes" and the German magazine "STERN", Kim Phúc got the opportunity to meet and get treated by Professor Zellner. Professor Peter Rudolph Zellner was the first chief of the Department of Hand, Plastic and Reconstructive Surgery, Burn Center, BG Trauma Center Ludwigshafen, and one of the founder members of the German Society of Plastic Surgeons. The reconstructive surgeries provide Kim Phúc an almost normal life. Later on, she was involved in international aid organizations; she was named a UNESCO Goodwill Ambassador and she was awarded several honorary Doctorates of Law. Kim Phúc became a Canadian citizen. Today, she lives with her husband and two children in Ontario, Canada. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Urinary KIM-1 and AQP-1 in patients with clear renal cell carcinoma: Potential noninvasive biomarkers

    Directory of Open Access Journals (Sweden)

    Mijušković Mirjana

    2016-01-01

    Full Text Available Background/Aim. Kidney injury molecule-1 (KIM-1 and aquaporin-1 (AQP-1 are potential early urinary biomarkers of clear renal cell carcinoma (cRCC. The aim of this study was to ascertain relationship between the urine concentrations KIM-1 and AQP-1 with tumor size, grade, pT stage and type of operation (radical or partial nephrectomy in patients with cRCC. Methods. Urinary concentrations of urinary KIM-1 (uKIM-1 and urinary AQP-1 (uAQP-1 were determined by commercially available ELISA kits. The analysis included 40 patients undergoing partial or radical nephrectomy for cRCC and 40 age- and sex-matched healthy adult volunteers. Results. The median preoperative concentrations of KIM-1 in the cRCC group [0.724 ± 1.120 ng/mg urinary creatinine (Ucr] were significantly greater compared with controls (healthy volunteers (0.210 ± 0.082 ng/mgUcr (p = 0.0227. Postoperatively, uKIM-1 concentration decreased significantly to control values (0.177 ± 0.099 ng/mgUcr vs 0.210 ± 0.082 ng/mgUcr, respectively. The size, grade and stage of tumor were correlated positively with preoperative uKIM-1 concentrations. Contrary to these results, concentrations of uAQP-1 in the cRCC group were significantly lower (0.111 ± 0.092 ng/mgUcr compared with the control group (0.202 ± 0.078 ng/mgUcr (p = 0.0014. Postoperatively, the concentrations of uAQP-1 increased progressively up to control values, approximately. We find no significant correlation between preoperative uAQP-1 concentrations and tumor size, grade and stage. Conclusion. uKIM-1 was found to be a reliable diagnostic marker of cRCC, based on its significantly increased values before and decreased values after the nephrectomy. [Projekat Ministarstva nauke Republike Srbije, br. III41018

  17. Current collapse modeling in AlGaN/GaN HEMT using small signal equivalent circuit for high power application

    Science.gov (United States)

    Nirmal, D.; Arivazhagan, L.; Fletcher, A. S. Augustine; Ajayan, J.; Prajoon, P.

    2018-01-01

    In this paper, the drain current collapse in AlGaN/GaN High Electron Mobility Transistor (HEMT) with field plate engineering is investigated. A small signal equivalent circuit of AlGaN/GaN HEMT is developed and a new drain current model is derived. This model is useful to correlate the impact of intrinsic capacitance and conductance on drain current collapse. The proposed device suppressed the current collapse phenomena by 10% compared with the conventional AlGaN/GaN HEMT. Moreover, the DC characteristics of the simulated device shows a drain current of 900 mA/mm, breakdown voltage of 291 V and transconductance of 175 mS/mm. Besides, the intrinsic capacitance and conductance parameters are extracted and its impact on drain current is analysed. Finally, the simulation results obtained were in compliance with the derived mathematical model of AlGaN/GaN HEMT.

  18. Evaluation of SiN films for AlGaN/GaN MIS-HEMTs on Si(111)

    Energy Technology Data Exchange (ETDEWEB)

    Cordier, Y.; Lecotonnec, A.; Chenot, S. [CRHEA-CNRS, Valbonne (France); Baron, N. [CRHEA-CNRS, Valbonne (France); PICOGIGA International, Courtaboeuf (France); Nacer, F.; Goullet, A.; Besland, M.P. [Institut des Materiaux Jean Rouxel IMN, Universite de Nantes (France); Lhermite, H. [Institut d' Electronique et de Telecommunications de Rennes (IETR), Universite de Rennes 1 (France); El Kazzi, M.; Regreny, P.; Hollinger, G. [Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, UMR CNRS, Ecully (France)

    2009-06-15

    In this work, AlGaN/GaN HEMT structures grown on Si(111) substrates were covered with SiN{sub x} dielectric films, in order to realize MIS-HEMT devices. The dielectric films have been deposited by plasma enhanced chemical vapor deposition using deposition conditions previously optimized for InP based devices. X-ray photoelectron spectroscopy was used to control the interface formation and characterize the deposited films. Capacitance-voltage, Hall effect and current-voltage measurements were carried out on the MIS-HEMTs and HEMT reference devices and correlated with the dielectric layer quality. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Ultra-Low Inductance Design for a GaN HEMT Based 3L-ANPC Inverter

    DEFF Research Database (Denmark)

    Gurpinar, Emre; Castellazzi, Alberto; Iannuzzo, Francesco

    2016-01-01

    In this paper, an ultra-low inductance power cell design for a 3L-ANPC based on 650 V GaN HEMT devices is presented. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which are the main...... contributors to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a four layer PCB with the aim to maximise the switching performance of GaN HEMTs is explained. Gate driver design for GaN HEMT devices is presented. Common-mode behaviours...

  20. The first clinical treatment with kilovoltage intrafraction monitoring (KIM): A real-time image guidance method

    DEFF Research Database (Denmark)

    Keall, Paul J.; Aun Ng, Jin; O'Brien, Ricky

    2015-01-01

    Purpose: Kilovoltage intrafraction monitoring (KIM) is a real-time image guidance method that uses widely available radiotherapy technology, i.e., a gantry-mounted x-ray imager. The authors report on the geometric and dosimetric results of the first patient treatment using KIM which occurred...... on September 16, 2014. Methods: KIM uses current and prior 2D x-ray images to estimate the 3D target position during cancer radiotherapy treatment delivery. KIM software was written to process kilovoltage (kV) images streamed from a standard C-arm linear accelerator with a gantry-mounted kV x-ray imaging...... system. A 120° pretreatment kV imaging arc was acquired to build the patient-specific 2D to 3D motion correlation. The kV imager was activated during the megavoltage (MV) treatment, a dual arc VMAT prostate treatment, to estimate the 3D prostate position in real-time. All necessary ethics, legal...

  1. Lõuna-Korea teatel võib Kim peagi surra / Evelyn Kaldoja

    Index Scriptorium Estoniae

    Kaldoja, Evelyn, 1980-

    2009-01-01

    Viidates Lõuna-Korea ja Hiina luureandmetele, väidab Lõuna-Korea meedia, et Põhja-Korea liidril Kim Jong-ilil on kõhunäärmevähk ja talle pole antud elada rohkem kui 5 aastat. Põhja-Korea valitsejadünastia

  2. A Misleading Review of Response Bias: Comment on McGrath, Mitchell, Kim, and Hough (2010)

    Science.gov (United States)

    Rohling, Martin L.; Larrabee, Glenn J.; Greiffenstein, Manfred F.; Ben-Porath, Yossef S.; Lees-Haley, Paul; Green, Paul; Greve, Kevin W.

    2011-01-01

    In the May 2010 issue of "Psychological Bulletin," R. E. McGrath, M. Mitchell, B. H. Kim, and L. Hough published an article entitled "Evidence for Response Bias as a Source of Error Variance in Applied Assessment" (pp. 450-470). They argued that response bias indicators used in a variety of settings typically have insufficient data to support such…

  3. The Limitations of Kim's reductive physicalism in accounting for living systems and an alternative nonreductionist ontology.

    Science.gov (United States)

    Perovic, Slobodan

    2007-01-01

    Jaegwon Kim's exclusion argument is a general ontological argument, applicable to any properties deemed supervenient on a microproperty basis, including biological properties. It implies that the causal power of any higher-level property must be reducible to the subset of the causal powers of its lower-level properties. Moreover, as Kim's recent version of the argument indicates, a higher-level property can be causally efficient only to the extent of the efficiency of its micro-basis. In response, I argue that the ontology that aims to capture experimentally based explanations of metabolic control systems and morphogenetic systems must involve causally relevant contextual properties. Such an ontology challenges the exclusiveness of micro-based causal efficiency that grounds Kim's reductionism, since configurations themselves are inherently causally efficient constituents. I anticipate and respond to the reductionist's objection that the nonreductionist ontology's account of causes and inter-level causal relations is incoherent. I also argue that such an ontology is not open to Kim's overdetermination objection.

  4. North Korea after Kim Chong-il: Leadership Dynamics and Potential Crisis Scenarios

    Science.gov (United States)

    2011-11-01

    genealogical link to his father through Confucian notions of filial piety and ancestor worship of Kim Il-sung as the “father” of the North Korean state...People’s Guerrilla War in the History of War,” Korean Central News Agency (December 16, 2006). 36 The “politics of loyalty and filial piety ” not

  5. Migrant Writing in Quebec : Female Mobility in Kim Thúy’s Ru

    NARCIS (Netherlands)

    den Toonder, Jeanette; Averis, Kate; Hollis-Touré, Isabel

    2016-01-01

    This chapter presents the experience of mobility as one of duality, an experience of both rupture and continuity as expressed in the poetic prose of Kim Thúy, resident in Quebec since her departure from her native Vietnam at ten years of age. Describing an experience of fragmented simultaneity that

  6. Against the Nihilism of Suffering and Death: Richard E. K. Kim and His Works

    Directory of Open Access Journals (Sweden)

    Jooyeon Rhee

    2016-03-01

    Full Text Available This article examines the life and works of Richard E. K. Kim (1932–2009, a first-generation Korean diasporic writer in the United States. It focuses on how Kim struggled to overcome the nihilism of suffering and death that derived from colonialism and the Korean War through his literary works. Kim witnessed firsthand these two major historical events, which caused irrevocable psychological and physical damage to many people of his generation. In his autobiographical fiction, he conveys painful memories of the events by reviving the voices of people in that era. What his works offer us goes beyond vivid memories of the past, however; they also present the power of forgiveness as a condition to overcome the nihilism of suffering and death. Remembrance and forgiveness are, therefore, two major thematic pillars of his works that enable us to connect to these difficult and traumatic times. These themes are portrayed in such a gripping way mainly because Kim tried to maintain a certain distance—an emotional and linguistic distance—from the familiar, in order to elucidate the reality of the human condition: an ontological position of the exile from which he produced his works. This article argues that Kim’s works provide us the possibility to transcend the nihilism of historical trauma through articulating the meaning of remembrance and forgiveness from his self-assumed position of exile.

  7. Non-integrability of the Armbruster-Guckenheimer-Kim quartic Hamiltonian through Morales-Ramis theory

    OpenAIRE

    Acosta-Humánez, P.; Alvarez-Ramírez, M.; Stuchi, T.

    2017-01-01

    We show the non-integrability of the three-parameter Armburster-Guckenheimer-Kim quartic Hamiltonian using Morales-Ramis theory, with the exception of the three already known integrable cases. We use Poincar\\'e sections to illustrate the breakdown of regular motion for some parameter values.

  8. New neoplasm during GH replacement in adults with pituitary deficiency following malignancy- a KIMS analysis

    DEFF Research Database (Denmark)

    Krzyzanowska-Mittermayer, Katarzyna; Mattsson, Anders F; Maiter, Dominique

    2018-01-01

    (CS). Design: Retrospective comparison of CO-CS and AO-CS with CO idiopathic GHD (IGHD) and AO non-functioning pituitary adenoma patients (NFPA) and with the general population (standardized incidence ratio, SIR). Setting: Data from KIMS study (Pfizer International Metabolic Database). Patients: CO...

  9. From isolated GH deficiency to multiple pituitary hormone deficiency: an evolving continuum - a KIMS analysis

    DEFF Research Database (Denmark)

    Klose, M.; Jonsson, B.; Abs, R.

    2009-01-01

    with organic AO-GHD, who were GH naive prior to entry into the Pfizer International Metabolic Database (KIMS; 283 (7%) IGHD, 3827 MPHD). The effect of GH replacement after 2 years was assessed in those with available follow-up data (133 IGHD, 2207 MPHD), and development of new deficiencies in those...

  10. Arhitektuurimuuseum vaatab Aasiasse / Kim Sung Hong ; intervjueerinud Karin Hallas-Murula

    Index Scriptorium Estoniae

    Kim Sung Hong

    2009-01-01

    Näituse kuraatori Kim Sung Hongiga 21. aprillini Eesti Arhitektuurimuuseumis avatud Lõuna-Korea kaasaegse arhitektuuri näitusest "Megacity network" ("Megalinna võrgustik"), Korea arhitektuurist, arhitektidest, muinsuskaitsest ja avalikust ruumist. Näituse kujundas Hwang Doo Jin

  11. Drain current DLTS of AlGaN/GaN HEMTs

    Energy Technology Data Exchange (ETDEWEB)

    Mizutani, T.; Okino, T.; Kawada, K.; Ohno, Y.; Kishimoto, S.; Maezawa, K. [Department of Quantum Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2003-11-01

    The transient behaviour of AlGaN/GaN HEMTs was studied by current DLTS. One electron trap and two hole-trap-like signals were observed. The electron trap had an activation energy of 0.61 eV, which was similar to the defect level in n-GaN obtained by capacitance DLTS. It has been pointed out that the hole-trap-like signals dit not originate from changes in hole trap population in the channel, but probably reflected the changes in the electron population in the surface states of the HEMT access regions. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Improved large-signal GaN HEMT model suitable for intermodulation distortion analysis

    Science.gov (United States)

    Liu, Lin-Sheng; Luo, Ji

    2011-12-01

    In this article, a complete empirical large-signal model of GaN high electron-mobility transistors (HEMTs) is presented. The developed nonlinear model employs differentiable trigonometric function continuously to describe the drain-source current characteristic and its higher order derivatives, making itself suitable for the simulation of intermodulation distortion (IMD) in microwave circuits. Besides, an improved charge-conservative gate charge model is proposed to accurately trace the nonlinear gate-source and gate-drain capacitances. The model validity is demonstrated for different 0.25-µm gate-length GaN HEMTs. The simulation results of small-signal S-parameters, radio frequency (RF) large-signal power performances and two-tone IMD products show an excellent agreement with the measured data.

  13. Urinary Kidney Injury Molecule-1 (KIM-1 in Early Diagnosis of Acute Kidney Injury in Pediatric Critically Ill

    Directory of Open Access Journals (Sweden)

    Irma Lestari Paramastuty

    2016-04-01

    Full Text Available Acute kidney injury (AKI often associated with a high hospital morbi-mortality rate in the intensive care unit patients. Kidney injury molecule-1 (KIM-1, has many characteristics of ideal biomarker for kidney injury. The aim of this study was to compared the temporal pattern of elevation urinary KIM-1 level following critically ill children with SCr as standart biomarker of AKI. Prospective analytic observational study was conducted during October to March 2014 in the Saiful Anwar General Hospital and Physiology Laboratory Brawijaya University. There were 13 critically ill as subjects. SCr and KIM-1 levels from all subjects were measured three times ( at admission, after 1st and 6th hour. Subjects were devided into AKI - non-AKI groups by SCr level and survivor - non survivor group at the and of the observations. Results showed that there were significantly increased levels of KIM-1 in the AKI and non-AKI and survivor-non survivor group at time point. However, we found that delta KIM-1 at time point increased significant in non AKI group and survivor group. KIM-1 at admission can diagnosed AKI in critically ill children. We conclude that urinary KIM-1 is a sensitive non-invasive biomarker to diagnosed acute kidney injury in critically ill children. Increase level of KIM-1 by time shows protective and good outcome in critically ill children.

  14. Physical model for GaN HEMT design optimization in high frequency switching applications

    OpenAIRE

    Cucak, Dejana; Vasic, Miroslav; García, Oscar; Bouvier, Yann; Oliver Ramírez, Jesús Angel; Alou Cervera, Pedro; Cobos Márquez, José Antonio; Wang, Ashu; Martin Horcajo, Sara; Romero Rojo, Fátima; Calle Gómez, Fernando

    2014-01-01

    In this paper, physical modeling of a GaN HEMT is proposed, with the objective of device design optimization for application in a high frequency DC/DC converter. From the point of view of a switching application, physical model for input, output and reverse capacitance as well as for channel resistance is very important, since the aforementioned parameters determine power losses in the circuit. The obtained physical model of the switching device can be used for simulation models such as PSpic...

  15. Characterisation and analytical modeling of GaN HEMT-based varactor diodes

    OpenAIRE

    Hamdoun , Abdelaziz; Roy , L.; Himdi , Mohamed; Lafond , Olivier

    2015-01-01

    International audience; Varactor diodes fabricated in 0.5 and 0.15 μm GaN HEMT (high-electron-mobility transistor) processes are modelled. The devices were characterised via DC and RF small-signal measurements up to 20 GHz, and fitted to a simple physical equivalent circuit. Approximate analytical expressions containing empirical coefficients are introduced for the voltage dependency of capacitance and series resistance. The analytical solutions agree remarkably well with the experimentally e...

  16. Gate metal dependent electrical characteristics of AlGaN/GaN HEMTs

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Sang-Mo, E-mail: smkoo@kw.ac.kr; Kang, Min-Seok, E-mail: hyde0220@gmail.com

    2014-10-15

    Highlights: • We investigated transfer characteristics of AlGaN/GaN high electron mobility transistors. • We demonstrate the effect of the barrier height of Schottky gate metals. • The conduction mechanisms examine by comparing the experimental results with numerical simulations. • 2-DEG concentration depends on the barrier height of Schottky gate metals. - Abstract: We investigated transfer characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) and the effect of the barrier height of Schottky gate metals. It is found that the threshold voltage of the HEMT structures with the Ni Schottky contact shows a positive shift compared to that of the Ti Schottky contacts (ΔV{sub th} = 2.9 V). The maximum saturation current of the HEMT structures with the Ti Schottky contact (∼1.4 × 10{sup 7} A/cm{sup 2}) is found to be ∼2.5 times higher than that of the Ni Schottky contact (2.9 × 10{sup 7} A/cm{sup 2}). The conduction mechanisms have been examined by comparing the experimental results with numerical simulations, which confirm that the increased barrier height is mainly attributed to the reduction of 2-DEG concentration.

  17. Numerical simulation of local doped barrier layer AlGaN/GaN HEMTs

    Science.gov (United States)

    Fu, Wenli; Xu, Yuehang; Yan, Bo; Zhang, Bin; Xu, Ruimin

    2013-08-01

    A GaN HEMT with local doped barrier layer is proposed in this paper. The DC and RF characteristics of the proposed GaN HEMT structure is analyzed by using 2D numerical simulation. The results show that the breakdown voltage is 23% larger than that of the entire doped barrier layer structure due to the extension of depletion layer width between gate and drain electrodes, which reduces the electric field peak value at the right corner of the gate. A theoretical maximum output power density of 16.2 W/mm has been achieved, which is ∼34% larger than that of the entire doped barrier layer structure, and 7% larger than that of the unintentionally doped barrier layer structure. And the RF simulation results show that the proposed GaN HEMT also improved the maximum stable gain (MSG) by 0.8 dB up to 25 GHz due to the decrease of the gate-drain capacitance compared to the unintentionally doped and entire doped barrier layer structures.

  18. Noise characterization of enhancement-mode AlGaN graded barrier MIS-HEMT devices

    Science.gov (United States)

    Mohanbabu, A.; Saravana Kumar, R.; Mohankumar, N.

    2017-12-01

    This paper reports a systematic theoretical study on the microwave noise performance of graded AlGaN/GaN metal-insulator semiconductor high-electron mobility transistors (MIS-HEMTs) built on an Al2O3 substrate. The HfAlOx/AlGaN/GaN MIS-HEMT devices designed for this study show an outstanding small signal analog/RF and noise performance. The results on 1 μm gate length device show an enhancement mode operation with threshold voltage, VT = + 5.3 V, low drain leakage current, Ids,LL in the order of 1 × 10-9 A/mm along with high current gain cut-off frequency, fT of 17 GHz and maximum oscillation frequency fmax of 47 GHz at Vds = 10 V. The device Isbnd V and low-frequency noise estimation of the gate and drain noise spectral density and their correlation are evaluated using a Green's function method under different biasing conditions. The devices show a minimum noise figure (NFmin) of 1.053 dB in combination with equivalent noise resistance (Rn) of 23 Ω at 17 GHz, at Vgs = 6 V and Vds = 5 V which is relatively low and is suitable for broad-band low-noise amplifiers. This study shows that the graded AlGaN MIS-HEMT with HfAlOX gate insulator is appropriate for application requiring high-power and low-noise.

  19. Effects of combined gate and ohmic recess on GaN HEMTs

    Directory of Open Access Journals (Sweden)

    Sunil Kumar

    2016-09-01

    Full Text Available AlGaN/GaN, because of their superior material properties, are most suitable semiconductor material for High Electron Mobility Transistors (HEMTs. In this work we investigated the hidden physics behind these materials and studied the effect of recess technology in AlGaN/GaN HEMTs. The device under investigation is simulated for different recess depth using Silvaco-Atlas TCAD. Recess technology improves the performance of AlGaN/GaN HEMTs. We considered three kinds of recess technology gate, ohmic and combination of gate and ohmic. Gate recess improves transconductance gm but it reduces the drain current Id of the device under investigation. Ohmic recess improves the transconductance gm but it introduces leakage current Ig in the device. In order to use AlGaN/GaN for high voltage operation, both the transconductance and the drain current should be reasonably high which is obtained by combining both gate and ohmic recess technologies. A good balance in transconductance and drain current is achieved by combining both gate and ohmic recess technologies without any leakage current.

  20. A novel GaN HEMT with double recessed barrier layer for high efficiency-energy applications

    Science.gov (United States)

    Jia, Hujun; Luo, Yehui; Wu, Qiuyuan; Yang, Yintang

    2017-11-01

    In this paper, a novel GaN HEMT with high efficiency-energy characteristic is proposed. Different from the conventional structure, the proposed structure contains double recessed barriers layer (DRBL) beside the gate. The key idea in this work is to improve the microwave output characteristics. The simulated results show that the drain saturation current and peak transconductance of DRBL GaN HEMT is slightly decreased, the transconductance saturation flatness is increased by 0.5 V and the breakdown voltage is also enhanced too. Due to the both recessed barrier layer, the gate-drain/gate-source capacitance is decreased by 6.3% and 11.3%, respectively. The RF simulated results show that the maximum oscillation frequency for DRBL GaN HEMT is increased from 57 GHz to 64 GHz and the saturation power density is 8.7 W/mm at 600 MHz, 6.9 W/mm at 1200 MHz with the higher power added efficiency (PAE). Further investigation show that DRBL GaN HEMT can achieve to 6.4 W/mm and the maximum PAE 83.8% at 2400 MHz. Both are higher than the 5.0 W/mm and 80.3% for the conventional structure. When the operating frequency increases to X band, the DRBL GaN HEMT still exhibits the superior output performances. All the results show that the advantages and the potential capacities of DRBL GaN HEMT at high efficiency-energy are greater than the conventional GaN HEMT.

  1. The diagnostic importance of the new marker KIM-1 in kidney damage

    Directory of Open Access Journals (Sweden)

    Zofia Marchewka

    2013-07-01

    Full Text Available In recent years, the rapid development of scientific research led to the introduction of strategies based on new markers that allow for estimation of the latent disease period before the clinical symptoms of actual kidney failure are revealed.The experimental tests carried out on animals and cell lines derived from the proximal tubule have made possible the detection of genes that are induced early after hypoxia [1].The protein products of these genes can be considered as useful markers for the diagnosis of renal failure. The induction of gene KIM-1 (called Kidney Injury Molecule-1 results in the formation of protein that can be considered as a diagnostic marker.This work describes the data on the structure, biological function and importance of determining the concentrations of KIM-1 in the diagnosis of drug-induced toxicity and kidney damage.

  2. Ab initio and Gordon--Kim intermolecular potentials for two nitrogen molecules

    International Nuclear Information System (INIS)

    Ree, F.H.; Winter, N.W.

    1980-01-01

    Both ab initio MO--LCAO--SCF and the electron-gas (or Gordon--Kim) methods have been used to compute the intermolecular potential (Phi) of N 2 molecules for seven different N 2 --N 2 orientations. The ab initio calculations were carried out using a [4s3p] contracted Gaussian basis set with and without 3d polarization functions. The larger basis set provides adequate results for Phi>0.002 hartree or intermolecular separations less than 6.5--7 bohr. We use a convenient analytic expression to represent the ab initio data in terms of the intermolecular distance and three angles defining the orientations of the two N 2 molecules. The Gordon--Kim method with Rae's self-exchange correction yields Phi, which agrees reasonably well over a large repulsive range. However, a detailed comparison of the electron kinetic energy contributions shows a large difference between the ab initio and the Gordon--Kim calculations. Using the ab initio data we derive an atom--atom potential of the two N 2 molecules. Although this expression does not accurately fit the data at some orientations, its spherical average agrees with the corresponding average of the ab initio Phi remarkably well. The spherically averaged ab initio Phi is also compared with the corresponding quantities derived from experimental considerations. The approach of the ab initio Phi to the classical quadrupole--quadrupole interaction at large intermolecular separation is also discussed

  3. Development and characteristic analysis of a field-plated Al2O3/AlInN/GaN MOS—HEMT

    International Nuclear Information System (INIS)

    Mao Wei; Hao Yao; Zhang Jin-Cheng; Liu Hong-Xia; Bi Zhi-Wei; Xu Sheng-Rui; Xue Jun-Shuai; Ma Xiao-Hua; Wang Chong; Yang Lin-An; Zhang Jin-Feng; Kuang Xian-Wei; Yang Cui

    2011-01-01

    We present an AlInN/AlN/GaN MOS—HEMT with a 3 nm ultra-thin atomic layer deposition (ALD) Al 2 O 3 dielectric layer and a 0.3 μm field-plate (FP)-MOS—HEMT. Compared with a conventional AlInN/AlN/GaN HEMT (HEMT) with the same dimensions, a FP-MOS—HEMT with a 0.6 μm gate length exhibits an improved maximum drain current of 1141 mA/mm, an improved peak extrinsic transconductance of 325 mS/mm and effective suppression of gate leakage in both the reverse direction (by about one order of magnitude) and the forward direction (by more than two orders of magnitude). Moreover, the peak extrinsic transconductance of the FP-MOS—HEMT is slightly larger than that of the HEMT, indicating an exciting improvement of transconductance performance. The sharp transition from depletion to accumulation in the capacitance—voltage (C—V) curve of the FP-MOS—HEMT demonstrates a high-quality interface of Al 2 O 3 /AlInN. In addition, a large off-state breakdown voltage of 133 V, a high field-plate efficiency of 170 V/μm and a negligible double-pulse current collapse is achieved in the FP-MOS—HEMT. This is attributed to the adoption of an ultra-thin Al 2 O 3 gate dielectric and also of a field-plate on the dielectric of an appropriate thickness. The results show a great potential application of the ultra-thin ALD-Al 2 O 3 FP-MOS—HEMT to deliver high currents and power densities in high power microwave technologies. (rapid communication)

  4. Development and characteristic analysis of a field-plated Al2O3/AlInN/GaN MOS—HEMT

    Science.gov (United States)

    Mao, Wei; Yang, Cui; Hao, Yao; Zhang, Jin-Cheng; Liu, Hong-Xia; Bi, Zhi-Wei; Xu, Sheng-Rui; Xue, Jun-Shuai; Ma, Xiao-Hua; Wang, Chong; Yang, Lin-An; Zhang, Jin-Feng; Kuang, Xian-Wei

    2011-01-01

    We present an AlInN/AlN/GaN MOS—HEMT with a 3 nm ultra-thin atomic layer deposition (ALD) Al2O3 dielectric layer and a 0.3 μm field-plate (FP)-MOS—HEMT. Compared with a conventional AlInN/AlN/GaN HEMT (HEMT) with the same dimensions, a FP-MOS—HEMT with a 0.6 μm gate length exhibits an improved maximum drain current of 1141 mA/mm, an improved peak extrinsic transconductance of 325 mS/mm and effective suppression of gate leakage in both the reverse direction (by about one order of magnitude) and the forward direction (by more than two orders of magnitude). Moreover, the peak extrinsic transconductance of the FP-MOS—HEMT is slightly larger than that of the HEMT, indicating an exciting improvement of transconductance performance. The sharp transition from depletion to accumulation in the capacitance—voltage (C—V) curve of the FP-MOS—HEMT demonstrates a high-quality interface of Al2O3/AlInN. In addition, a large off-state breakdown voltage of 133 V, a high field-plate efficiency of 170 V/μm and a negligible double-pulse current collapse is achieved in the FP-MOS—HEMT. This is attributed to the adoption of an ultra-thin Al2O3 gate dielectric and also of a field-plate on the dielectric of an appropriate thickness. The results show a great potential application of the ultra-thin ALD-Al2O3 FP-MOS—HEMT to deliver high currents and power densities in high power microwave technologies.

  5. Phenotypic characterization of OmpX, an Ail homologue of Yersinia pestis KIM.

    Science.gov (United States)

    Kolodziejek, Anna M; Sinclair, Dylan J; Seo, Keun S; Schnider, Darren R; Deobald, Claudia F; Rohde, Harold N; Viall, Austin K; Minnich, Scott S; Hovde, Carolyn J; Minnich, Scott A; Bohach, Gregory A

    2007-09-01

    The goal of this study was to characterize the Yersinia pestis KIM OmpX protein. Yersinia spp. provide a model for studying several virulence processes including attachment to, and internalization by, host cells. For Yersinia enterocolitica and Yersinia pseudotuberculosis, Ail, YadA and Inv, have been implicated in these processes. In Y. pestis, YadA and Inv are inactivated. Genomic analysis of two Y. pestis strains revealed four loci with sequence homology to Ail. One of these genes, designated y1324 in the Y. pestis KIM database, encodes a protein designated OmpX. The mature protein has a predicted molecular mass of 17.47 kDa, shares approximately 70 % sequence identity with Y. enterocolitica Ail, and has an identical homologue, designated Ail, in the Y. pestis CO92 database. The present study compared the Y. pestis KIM6(+) parental strain with a mutant derivative having an engineered disruption of the OmpX structural gene. The parental strain (and a merodiploid control strain) expressed OmpX at 28 and 37 degrees C, and the protein was detectable throughout all phases of growth. OmpX was required for efficient adherence to, and internalization by, cultured HEp-2 cell monolayers and conferred resistance to the bactericidal effect of human serum. Deletion of ompX resulted in a significantly reduced autoaggregation phenotype and loss of pellicle formation in vitro. These results suggest that Y. pestis OmpX shares functional homology with Y. enterocolitica Ail in adherence, internalization into epithelial cells and serum resistance.

  6. A Very Robust AlGaN/GaN HEMT Technology to High Forward Gate Bias and Current

    Directory of Open Access Journals (Sweden)

    Bradley D. Christiansen

    2012-01-01

    Full Text Available Reports to date of GaN HEMTs subjected to forward gate bias stress include varied extents of degradation. We report an extremely robust GaN HEMT technology that survived—contrary to conventional wisdom—high forward gate bias (+6 V and current (>1.8 A/mm for >17.5 hours exhibiting only a slight change in gate diode characteristic, little decrease in maximum drain current, with only a 0.1 V positive threshold voltage shift, and, remarkably, a persisting breakdown voltage exceeding 200 V.

  7. Simulation of Enhancement Mode GaN HEMTs with Threshold > 5 V using P-type Buffer

    OpenAIRE

    Bajaj, Sanyam; Akyol, Fatih; Krishnamoorthy, Sriram; Hung, Ting-Hsiang; Rajan, Siddharth

    2015-01-01

    A high threshold voltage enhancement-mode GaN HEMT with p-type doped buffer is discussed and simulated. Analytical expressions are derived to explain the role of buffer capacitance in designing and enhancing threshold voltage. Simulations of the proposed device with p-type buffer show threshold voltages above 5 V, and a positive shift in threshold voltage as the oxide capacitance is reduced, thus enabling threshold voltage tunability over an unprecedented range for GaN-based HEMTs. The electr...

  8. Driving of a GaN enhancement mode HEMT transistor with zener diode protection for high efficiency and low EMI

    OpenAIRE

    Spro, Ole Christian; Basu, Supratim; Abuishmais, Ibrahim Abed; Midtgård, Ole-Morten; Undeland, Tore Marvin

    2017-01-01

    The ultra-low gate charge characteristics and low gate voltage limitation of a GaN enhancement mode HEMT in combination with stray circuit elements poses many challenges of driving them in power electronic applications. This paper investigates the effect of changing gate resistances and including a Zener diode for overvoltage protection in the gate circuit. The goal is to achieve low switching losses and low EMC signature. Due to the very low gate capacitance of the GaN HEMT compared to the j...

  9. Photoresponse and trap characteristics of transparent AZO-gated AlGaN/GaN HEMT

    Science.gov (United States)

    Wang, Chong; Zhao, Meng-Di; He, Yun-Long; Zheng, Xue-Feng; Zhang, Kun; Wei, Xiao-Xiao; Mao, Wei; Ma, Xiao-Hua; Zhang, Jin-Cheng; Hao, Yue

    2016-10-01

    AZO-gated and Ni/Au-gated AlGaN/GaN HEMTs are fabricated successfully, and an excellent transparency of AZO-gated electrode is achieved. After a negative gate bias stress acts on two kinds of the devices, their photoresponse characteristics are investigated by using laser sources with different wavelengths. The effect of photoresponse on AZO-gated electrode device is more obvious than on Ni/Au-gated electrodes device. The electrons are trapped in the AlGaN barrier of AZO-gated HEMT after it has experienced negative gate bias stress, and then the electrons can be excited effectively after it has been illuminated by the light with certain wavelengths. Furthermore, the trap state density D T and the time constant τ T of the AZO-gated Schottky contact are extracted by fitting the measured parallel conductance in a frequency range from 10 kHz to 10 MHz. The constants of the trap range from about 0.35 μs to 20.35 μs, and the trap state density increased from 1.93 × 1013 eV-1·cm-2 at an energy of 0.33 eV to 3.07 × 1011 eV-1·cm-2 at an energy of 0.40 eV. Moreover, the capacitance and conductance measurements are used to characterize the trapping effects under different illumination conditions in AZO-gated HEMTs. Reduced deep trap states' density is confirmed under the illumination of short wavelength light. Project supported by the National Natural Science Foundation of China (Grant Nos. 61574110, 61574112, and 61106106).

  10. Photoresponse and trap characteristics of transparent AZO-gated AlGaN/GaN HEMT

    International Nuclear Information System (INIS)

    Wang Chong; Zhao Meng-Di; He Yun-Long; Zheng Xue-Feng; Zhang Kun; Wei Xiao-Xiao; Mao Wei; Ma Xiao-Hua; Zhang Jin-Cheng; Hao Yue

    2016-01-01

    AZO-gated and Ni/Au-gated AlGaN/GaN HEMTs are fabricated successfully, and an excellent transparency of AZO-gated electrode is achieved. After a negative gate bias stress acts on two kinds of the devices, their photoresponse characteristics are investigated by using laser sources with different wavelengths. The effect of photoresponse on AZO-gated electrode device is more obvious than on Ni/Au-gated electrodes device. The electrons are trapped in the AlGaN barrier of AZO-gated HEMT after it has experienced negative gate bias stress, and then the electrons can be excited effectively after it has been illuminated by the light with certain wavelengths. Furthermore, the trap state density D T and the time constant τ T of the AZO-gated Schottky contact are extracted by fitting the measured parallel conductance in a frequency range from 10 kHz to 10 MHz. The constants of the trap range from about 0.35 μs to 20.35 μs, and the trap state density increased from 1.93 × 10 13 eV −1 ·cm −2 at an energy of 0.33 eV to 3.07 × 10 11 eV −1 ·cm −2 at an energy of 0.40 eV. Moreover, the capacitance and conductance measurements are used to characterize the trapping effects under different illumination conditions in AZO-gated HEMTs. Reduced deep trap states' density is confirmed under the illumination of short wavelength light. (paper)

  11. Enhanced terahertz detection using multiple GaAs HEMTs connected in series

    KAUST Repository

    Elkhatib, Tamer A.

    2012-07-28

    We report here, for the first time, on enhanced nonresonant detection of terahertz radiation using multiple InGaAs/GaAs high-electron-mobility transistors (HEMTs) connected in series and biased by a direct drain current. A 1.63 THz (184 mum) response is proportional to the number of detecting transistors operating in saturation region at the same gate-source bias voltage. The experimental data are in agreement with the detection mechanism based on the rectification of overdamped plasma waves excited by radiation in channels of devices.

  12. Multi-bias capacitance voltage characteristic of AlGaN/GaN HEMT

    International Nuclear Information System (INIS)

    Pu Yan; Wang Liang; Yuan Tingting; Ouyang Sihua; Pang Lei; Liu Guoguo; Luo Weijun; Liu Xinyu

    2010-01-01

    The method of multi-bias capacitance voltage measurement is presented. The physical meaning of gate-source and gate-drain capacitances in AlGaN/GaN HEMT and the variations in them with different bias conditions are discussed. A capacitance model is proposed to reflect the behaviors of the gate-source and gate-drain capacitances, which shows a good agreement with the measured capacitances, and the power performance obtains good results compared with the measured data from the capacitance model. (semiconductor devices)

  13. Reliability improvement in GaN HEMT power device using a field plate approach

    Science.gov (United States)

    Wu, Wen-Hao; Lin, Yueh-Chin; Chin, Ping-Chieh; Hsu, Chia-Chieh; Lee, Jin-Hwa; Liu, Shih-Chien; Maa, Jer-shen; Iwai, Hiroshi; Chang, Edward Yi; Hsu, Heng-Tung

    2017-07-01

    This study investigates the effect of implementing a field plate on a GaN high-electron-mobility transistor (HEMT) to improve power device reliability. The results indicate that the field plate structure reduces the peak electrical field and interface traps in the device, resulting in higher breakdown voltage, lower leakage current, smaller current collapse, and better threshold voltage control. Furthermore, after high voltage stress, steady dynamic on-resistance and gate capacitance degradation improvement were observed for the device with the field plate. This demonstrates that GaN device reliability can be improved by using the field plate approach.

  14. Multi-bias capacitance voltage characteristic of AlGaN/GaN HEMT

    Energy Technology Data Exchange (ETDEWEB)

    Pu Yan; Wang Liang; Yuan Tingting; Ouyang Sihua; Pang Lei; Liu Guoguo; Luo Weijun; Liu Xinyu, E-mail: puyan_66721@hotmail.co [Key Laboratory of Microelectronics Device and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China)

    2010-10-15

    The method of multi-bias capacitance voltage measurement is presented. The physical meaning of gate-source and gate-drain capacitances in AlGaN/GaN HEMT and the variations in them with different bias conditions are discussed. A capacitance model is proposed to reflect the behaviors of the gate-source and gate-drain capacitances, which shows a good agreement with the measured capacitances, and the power performance obtains good results compared with the measured data from the capacitance model. (semiconductor devices)

  15. Materials physics and device development for improved efficiency of GaN HEMT high power amplifiers.

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Steven Ross; Follstaedt, David Martin; Wright, Alan Francis; Baca, Albert G.; Briggs, Ronald D.; Provencio, Paula Polyak; Missert, Nancy A.; Allerman, Andrew Alan; Marsh, Phil F.; Koleske, Daniel David; Lee, Stephen Roger; Shul, Randy John; Seager, Carleton Hoover; Tigges, Christopher P.

    2005-12-01

    GaN-based microwave power amplifiers have been identified as critical components in Sandia's next generation micro-Synthetic-Aperture-Radar (SAR) operating at X-band and Ku-band (10-18 GHz). To miniaturize SAR, GaN-based amplifiers are necessary to replace bulky traveling wave tubes. Specifically, for micro-SAR development, highly reliable GaN high electron mobility transistors (HEMTs), which have delivered a factor of 10 times improvement in power performance compared to GaAs, need to be developed. Despite the great promise of GaN HEMTs, problems associated with nitride materials growth currently limit gain, linearity, power-added-efficiency, reproducibility, and reliability. These material quality issues are primarily due to heteroepitaxial growth of GaN on lattice mismatched substrates. Because SiC provides the best lattice match and thermal conductivity, SiC is currently the substrate of choice for GaN-based microwave amplifiers. Obviously for GaN-based HEMTs to fully realize their tremendous promise, several challenges related to GaN heteroepitaxy on SiC must be solved. For this LDRD, we conducted a concerted effort to resolve materials issues through in-depth research on GaN/AlGaN growth on SiC. Repeatable growth processes were developed which enabled basic studies of these device layers as well as full fabrication of microwave amplifiers. Detailed studies of the GaN and AlGaN growth of SiC were conducted and techniques to measure the structural and electrical properties of the layers were developed. Problems that limit device performance were investigated, including electron traps, dislocations, the quality of semi-insulating GaN, the GaN/AlGaN interface roughness, and surface pinning of the AlGaN gate. Surface charge was reduced by developing silicon nitride passivation. Constant feedback between material properties, physical understanding, and device performance enabled rapid progress which eventually led to the successful fabrication of state of the

  16. SEMICONDUCTOR DEVICES Multi-bias capacitance voltage characteristic of AlGaN/GaN HEMT

    Science.gov (United States)

    Yan, Pu; Liang, Wang; Tingting, Yuan; Sihua, Ouyang; Lei, Pang; Guoguo, Liu; Weijun, Luo; Xinyu, Liu

    2010-10-01

    The method of multi-bias capacitance voltage measurement is presented. The physical meaning of gate—source and gate—drain capacitances in AlGaN/GaN HEMT and the variations in them with different bias conditions are discussed. A capacitance model is proposed to reflect the behaviors of the gate—source and gate—drain capacitances, which shows a good agreement with the measured capacitances, and the power performance obtains good results compared with the measured data from the capacitance model.

  17. Design of a GaAs X-ray imaging sensor with integrated HEMT readout circuitry

    Energy Technology Data Exchange (ETDEWEB)

    Boardman, D

    2002-01-01

    A new monolithic semi-insulating (SI) GaAs sensor design for X-ray imaging applications between 10-100keV has been proposed. Monolithic pixel detectors offer a number of advantages over hybrid bump-bonded detectors, such as high device yield, low costs and are easier to produce large scale arrays. In this thesis, an investigation is made of the use of a SI GaAs wafer as both a detector element and substrate for the epitaxially grown High Electron Mobility Transistors (HEMTs). The design of the HEMT transistors, optimised for this application, were produced with the aid of the Silvaco 'Virtual Wafer Fab' simulation package. It was determined that the device characteristics would consist of a small positive threshold voltage, a low off-state drain current and high transconductance. The final HEMT transistor design, that would be integrated to a pixel detector, had a threshold voltage of 0.17V, an off-state leakage current of {approx}1nA and a transconductance of 7.4mS. A number of test detectors were characterised using an ion beam induced charge technique. Charge collection efficiency maps of the test detectors were produced to determine their quality as a X-ray detection material. From the results, the inhomogeneity of SI GaAs, homogeneity of epitaxial GaAs and granular nature of polycrystalline GaAs, were observed. The best of these detectors was used in conjunction with a commercial field effect transistor to produce a hybrid device. The charge switching nature of the hybrid device was shown and a sensitivity of 0.44pC/{mu}Gy mm{sup 2}, for a detector bias of 60V, was found. The functionality of the hybrid sensor was the same to that proposed for the monolithic sensor. The fabrication of the monolithic sensor, with an integrated HEMT transistor and external capacitor, was achieved. To reach the next stage of producing a monolithic sensor that integrates charge, requires further work in the design and the fabrication process. (author)

  18. Design of a GaAs X-ray imaging sensor with integrated HEMT readout circuitry

    International Nuclear Information System (INIS)

    Boardman, D.

    2002-01-01

    A new monolithic semi-insulating (SI) GaAs sensor design for X-ray imaging applications between 10-100keV has been proposed. Monolithic pixel detectors offer a number of advantages over hybrid bump-bonded detectors, such as high device yield, low costs and are easier to produce large scale arrays. In this thesis, an investigation is made of the use of a SI GaAs wafer as both a detector element and substrate for the epitaxially grown High Electron Mobility Transistors (HEMTs). The design of the HEMT transistors, optimised for this application, were produced with the aid of the Silvaco 'Virtual Wafer Fab' simulation package. It was determined that the device characteristics would consist of a small positive threshold voltage, a low off-state drain current and high transconductance. The final HEMT transistor design, that would be integrated to a pixel detector, had a threshold voltage of 0.17V, an off-state leakage current of ∼1nA and a transconductance of 7.4mS. A number of test detectors were characterised using an ion beam induced charge technique. Charge collection efficiency maps of the test detectors were produced to determine their quality as a X-ray detection material. From the results, the inhomogeneity of SI GaAs, homogeneity of epitaxial GaAs and granular nature of polycrystalline GaAs, were observed. The best of these detectors was used in conjunction with a commercial field effect transistor to produce a hybrid device. The charge switching nature of the hybrid device was shown and a sensitivity of 0.44pC/μGy mm 2 , for a detector bias of 60V, was found. The functionality of the hybrid sensor was the same to that proposed for the monolithic sensor. The fabrication of the monolithic sensor, with an integrated HEMT transistor and external capacitor, was achieved. To reach the next stage of producing a monolithic sensor that integrates charge, requires further work in the design and the fabrication process. (author)

  19. Kim e a literatura colonial de língua inglesa

    Directory of Open Access Journals (Sweden)

    Vanderlei J. Zacchi

    2016-01-01

    Full Text Available Kim é não apenas um dos livros mais importantes de Rudyard Kipling, mas ocupa também posição de destaque na literatura de língua inglesa. Foi lançado em 1901, quando a Índia, onde se passa o romance, era ainda uma possessão britânica e doze anos após Kipling, tendo nascido na Índia, haver migrado para a Inglaterra. As relações entre os personagens orientais e britânicos no romance sugerem uma visão estereotipada das diferenças raciais e culturais. A aná- lise dessas relações será feita, em primeiro lugar, a partir de uma contextualização da literatura colonial de língua inglesa. Kim se insere numa segunda etapa dessa literatura, na qual predominava um ponto de vista predominantemente britânico e que buscava afirmar a legitimidade do império. E, em segundo lugar, a partir do conceito de orientalismo, conforme desenvolvido por Edward Said (1995. Esse conceito demonstra como os ocidentais fazem uso de sínteses e estereótipos para descrever o Oriente e conceber visões autorizadas sobre ele. Palavras-chave: Rudyard Kipling; literatura colonial; orientalismo

  20. Stopped depletion region extension in an AlGaN/GaN-HEMT: A new technique for improving high-frequency performance

    Science.gov (United States)

    Asad, Mohsen; Rahimian, Morteza

    2015-08-01

    We present a novel structure for AlGaN/GaN high electron mobility transistors. The structure consists of a multi-recess AlGaN barrier layer and recessed metal ring (RBRM-HEMT). The barrier thickness narrowing between the gate and the source/drain regions minimizes the depletion region extension, which leads to smaller gate-drain ( C GD ) and gate-source ( C GS ) capacitances. This technique shows a great improvement in high-frequency and high-power applications. In high-frequency operation, the cut-off frequency ( f T ) and the maximum oscillation frequency ( f max ) of the RBRM-HEMT are found to be 133 GHz and 216 GHz respectively, which is significantly higher than the 94 GHz and the 175 GHz obtained for the conventional GaN HEMT (C-HEMT). In addition, a more uniform and low-crowding electric field is obtained under the gate close to the drain side due to the recessed metal-ring structure. A 128% improvement in breakdown voltage ( V BR ) is achieved compared to the C-HEMT. Consequently, the maximum output power density ( P max ) is increased from 11.3 W/mm in the C-HEMT to 24.4 W/mm for the RBRM-HEMT.

  1. Analysis of the modulation mechanisms of the electric field and breakdown performance in AlGaN/GaN HEMT with a T-shaped field-plate

    International Nuclear Information System (INIS)

    Mao Wei; Fan Ju-Sheng; Du Ming; Zhang Jin-Feng; Zheng Xue-Feng; Wang Chong; Ma Xiao-Hua; Zhang Jin-Cheng; Hao Yue

    2016-01-01

    A novel AlGaN/GaN high electron mobility transistor (HEMT) with a source-connected T-shaped field-plate (ST-FP HEMT) is proposed for the first time in this paper. The source-connected T-shaped field-plate (ST-FP) is composed of a source-connected field-plate (S-FP) and a trench metal. The physical intrinsic mechanisms of the ST-FP to improve the breakdown voltage and the FP efficiency and to modulate the distributions of channel electric field and potential are studied in detail by means of two-dimensional numerical simulations with Silvaco-ATLAS. A comparison to the HEMT and the HEMT with an S-FP (S-FP HEMT) shows that the ST-FP HEMT could achieve a broader and more uniform channel electric field distribution with the help of a trench metal, which could increase the breakdown voltage and the FP efficiency remarkably. In addition, the relationship between the structure of the ST-FP, the channel electric field, the breakdown voltage as well as the FP efficiency in ST-FP HEMT is analyzed. These results could open up a new effective method to fabricate high voltage power devices for the power electronic applications. (paper)

  2. Analysis of the modulation mechanisms of the electric field and breakdown performance in AlGaN/GaN HEMT with a T-shaped field-plate

    Science.gov (United States)

    Mao, Wei; Fan, Ju-Sheng; Du, Ming; Zhang, Jin-Feng; Zheng, Xue-Feng; Wang, Chong; Ma, Xiao-Hua; Zhang, Jin-Cheng; Hao, Yue

    2016-12-01

    A novel AlGaN/GaN high electron mobility transistor (HEMT) with a source-connected T-shaped field-plate (ST-FP HEMT) is proposed for the first time in this paper. The source-connected T-shaped field-plate (ST-FP) is composed of a source-connected field-plate (S-FP) and a trench metal. The physical intrinsic mechanisms of the ST-FP to improve the breakdown voltage and the FP efficiency and to modulate the distributions of channel electric field and potential are studied in detail by means of two-dimensional numerical simulations with Silvaco-ATLAS. A comparison to the HEMT and the HEMT with an S-FP (S-FP HEMT) shows that the ST-FP HEMT could achieve a broader and more uniform channel electric field distribution with the help of a trench metal, which could increase the breakdown voltage and the FP efficiency remarkably. In addition, the relationship between the structure of the ST-FP, the channel electric field, the breakdown voltage as well as the FP efficiency in ST-FP HEMT is analyzed. These results could open up a new effective method to fabricate high voltage power devices for the power electronic applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 61574112, 61334002, 61306017, 61474091, and 61574110) and the Natural Science Basic Research Plan in Shaanxi Province, China (Grant No. 605119425012).

  3. Analysis of the thermal behavior of AlGaN/GaN HEMTs

    International Nuclear Information System (INIS)

    Russo, Salvatore; D’Alessandro, Vincenzo; Costagliola, Maurizio; Sasso, Grazia; Rinaldi, Niccolò

    2012-01-01

    Highlights: ► The thermal behavior of advanced multifinger AlGaN/GaN HEMTs grown on SiC is analyzed. ► The study is performed through accurate FEM simulations and DC/dynamic measurements. ► The FEM analysis is supported by an in-house tool devised for a smart mesh generation. ► Illustrative technology/layout guidelines to minimize the thermal issues are provided. - Abstract: The thermal behavior of state-of-the-art multifinger AlGaN/GaN HEMTs grown on SiC is thoroughly analyzed under steady-state and dynamic conditions. Accurate 3-D FEM simulations – based on a novel in-house tool devised to automatically build the device mesh – are performed using a commercial software to explore the influence of various layout and technological solutions on the temperature field. An in-house routine is employed to determine the Foster/Cauer networks suited to describe the dynamic heat propagation through the device structure. To conclude, various experimental techniques are employed to assess the thermal resistance and to allow the monitoring of the thermal impedance versus time of the transistors under test.

  4. Basic Equations for the Modeling of Gallium Nitride (gan) High Electron Mobility Transistors (hemts)

    Science.gov (United States)

    Freeman, Jon C.

    2003-01-01

    Gallium nitride (GaN) is a most promising wide band-gap semiconductor for use in high-power microwave devices. It has functioned at 320 C, and higher values are well within theoretical limits. By combining four devices, 20 W has been developed at X-band. GaN High Electron Mobility Transistors (HEMTs) are unique in that the two-dimensional electron gas (2DEG) is supported not by intentional doping, but instead by polarization charge developed at the interface between the bulk GaN region and the AlGaN epitaxial layer. The polarization charge is composed of two parts: spontaneous and piezoelectric. This behavior is unlike other semiconductors, and for that reason, no commercially available modeling software exists. The theme of this document is to develop a self-consistent approach to developing the pertinent equations to be solved. A Space Act Agreement, "Effects in AlGaN/GaN HEMT Semiconductors" with Silvaco Data Systems to implement this approach into their existing software for III-V semiconductors, is in place (summer of 2002).

  5. Progress in GaAs Metamorphic HEMT Technology for Microwave Applications. High Efficiency Ka-Band MHEMT Power MMICs

    Science.gov (United States)

    Smith, P. M.; Dugas, D.; Chu, K.; Nichols, K.; Duh, K. H.; Fisher, J.; MtPleasant, L.; Xu, D.; Gunter, L.; Vera, A.

    2003-01-01

    This paper reviews recent progress in the development of GaAs metamorphic HEMT (MHEMT) technology for microwave applications. Commercialization has begun, while efforts to further improve performance, manufacturability and reliability continue. We also report the first multi-watt MHEMT MMIC power amplifiers, demonstrating up to 3.2W output power and record power-added efficiency (PAE) at Ka-band.

  6. SEMICONDUCTOR DEVICES: Structural and electrical characteristics of lanthanum oxide gate dielectric film on GaAs pHEMT technology

    Science.gov (United States)

    Chia-Song, Wu; Hsing-Chung, Liu

    2009-11-01

    This paper investigates the feasibility of using a lanthanum oxide thin film (La2O3) with a high dielectric constant as a gate dielectric on GaAs pHEMTs to reduce gate leakage current and improve the gate to drain breakdown voltage relative to the conventional GaAs pHEMT. An E/D mode pHEMT in a single chip was realized by selecting the appropriate La2O3 thickness. The thin La2O3 film was characterized: its chemical composition and crystalline structure were determined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. La2O3 exhibited good thermal stability after post-deposition annealing at 200, 400 and 600 °C because of its high binding-energy (835.6 eV). Experimental results clearly demonstrated that the La2O3 thin film was thermally stable. The DC and RF characteristics of Pt/La2O3/Ti/Au gate and conventional Pt/Ti/Au gate pHEMTs were examined. The measurements indicated that the transistor with the Pt/La2O3/Ti/Au gate had a higher breakdown voltage and lower gate leakage current. Accordingly, the La2O3 thin film is a potential high-k material for use as a gate dielectric to improve electrical performance and the thermal effect in high-power applications.

  7. Characteristics of enhanced-mode AlGaN/GaN MIS HEMTs for millimeter wave applications

    Science.gov (United States)

    Lee, Jong-Min; Ahn, Ho-Kyun; Jung, Hyun-Wook; Shin, Min Jeong; Lim, Jong-Won

    2017-09-01

    In this paper, an enhanced-mode (E-mode) AlGaN/GaN high electron mobility transistor (HEMT) was developed by using 4-inch GaN HEMT process. We designed and fabricated Emode HEMTs and characterized device performance. To estimate the possibility of application for millimeter wave applications, we focused on the high frequency performance and power characteristics. To shift the threshold voltage of HEMTs we applied the Al2O3 insulator to the gate structure and adopted the gate recess technique. To increase the frequency performance the e-beam lithography technique was used to define the 0.15 um gate length. To evaluate the dc and high frequency performance, electrical characterization was performed. The threshold voltage was measured to be positive value by linear extrapolation from the transfer curve. The device leakage current is comparable to that of the depletion mode device. The current gain cut-off frequency and the maximum oscillation frequency of the E-mode device with a total gate width of 150 um were 55 GHz and 168 GHz, respectively. To confirm the power performance for mm-wave applications the load-pull test was performed. The measured power density of 2.32 W/mm was achieved at frequencies of 28 and 30 GHz.

  8. Prospects for 6-party talks: Nuclear weapons are a means of survival for Kim Jong Un

    International Nuclear Information System (INIS)

    Miyake, Kunihiko

    2012-04-01

    The author considers the impact of leader Kim Jong Il's death on 6-party talks surrounding the nuclear issue. Firstly, the history of these 6-party talks has to be reexamined to ensure an accurate understanding of their 'objectives and limitations' because the author believes that there are 3 'unpleasant truths' behind these talks, held 6 times since the summer of 2003, that no one wants to talk about. 1. North Korea has no interest in abandoning nuclear weapons; 2. Japan, the U.S., China, and South Korea do not want war; 3. The nuclear issue will not be resolved by 6-party talks. In fact, there is little potential that 6-party talks which aim to resolve the North Korean nuclear issue will move towards a new substantive agreement

  9. Bias in exponential and power function fits due to noise: comment on Myung, Kim, and Pitt.

    Science.gov (United States)

    Brown, Scott; Heathcote, Andrew

    2003-06-01

    Myung, Kim, and Pitt (2000) demonstrated that simple power functions almost always provide a better fit to purely random data than do simple exponential functions. This result has important implications, because it suggests that high noise levels, which are common in psychological experiments, may cause a bias favoring power functions. We replicate their result and extend it by showing strong bias for more realistic sample sizes. We also show that biases occur for data that contain both random and systematic components, as may be expected in real data. We then demonstrate that these biases disappear for two- or three-parameter functions that include linear parameters (in at least one parameterization). Our results suggest that one should exercise caution when proposing simple power and exponential functions as models of learning. More generally, our results suggest that linear parameters should be estimated rather than fixed when one is comparing the fit of nonlinear models to noisy data.

  10. From isolated GH deficiency to multiple pituitary hormone deficiency: an evolving continuum - a KIMS analysis

    DEFF Research Database (Denmark)

    Klose, M.; Jonsson, B.; Abs, R.

    2009-01-01

    OBJECTIVE: To describe baseline clinical presentation, treatment effects and evolution of isolated GH deficiency (IGHD) to multiple pituitary hormone deficiency (MPHD) in adult-onset (AO) GHD. DESIGN: Observational prospective study. METHODS: Baseline characteristics were recorded in 4110 patients...... with organic AO-GHD, who were GH naive prior to entry into the Pfizer International Metabolic Database (KIMS; 283 (7%) IGHD, 3827 MPHD). The effect of GH replacement after 2 years was assessed in those with available follow-up data (133 IGHD, 2207 MPHD), and development of new deficiencies in those...... with available data on concomitant medication (165 IGHD, 3006 MPHD). RESULTS: IGHD and MPHD patients had similar baseline clinical presentation, and both groups responded similarly to 2 years of GH therapy, with favourable changes in lipid profile and improved quality of life. New deficiencies were observed...

  11. Social influence of a religious hero: the late Cardinal Stephen Kim Sou-hwan's effect on cornea donation and volunteerism.

    Science.gov (United States)

    Bae, Hyuhn-Suhck; Brown, William J; Kang, Seok

    2011-01-01

    This study examined the mediated influence of a celebrated religious hero in South Korea, Cardinal Stephen Kim, through two forms of involvement--parasocial interaction and identification--on intention toward cornea donation and volunteerism, and it investigated how the news media diffused of his death. A structural equation modeling analysis with a Web-based voluntary survey of more than 1,200 people in South Korea revealed a multistep social influence process, beginning with parasocial interaction with Cardinal Kim, leading to identification with him, which predicted intention toward cornea donation and volunteerism. Additional investigations found that news of Cardinal Kim's death diffused rapidly through media and interpersonal communication. Results of this study demonstrate that religious leaders who achieve a celebrity hero status can prompt public discussion of important issues rather quickly through extensive media coverage, enabling them to promote prosocial behavior and positively affect public health.

  12. Improvement of breakdown characteristics of an AlGaN/GaN HEMT with a U-type gate foot for millimeter-wave power application

    Science.gov (United States)

    Kong, Xin; Wei, Ke; Liu, Guo-Guo; Liu, Xin-Yu

    2012-12-01

    In this study, the physics-based device simulation tool Silvaco ATLAS is used to characterize the electrical properties of an AlGaN/GaN high electron mobility transistor (HEMT) with a U-type gate foot. The U-gate AlGaN/GaN HEMT mainly features a gradually changed sidewall angle, which effectively mitigates the electric field in the channel, thus obtaining enhanced off-state breakdown characteristics. At the same time, only a small additional gate capacitance and decreased gate resistance ensure excellent RF characteristics for the U-gate device. U-gate AlGaN/GaN HEMTs are feasible through adjusting the etching conditions of an inductively coupled plasma system, without introducing any extra process steps. The simulation results are confirmed by experimental measurements. These features indicate that U-gate AlGaN/GaN HEMTs might be promising candidates for use in millimeter-wave power applications.

  13. Triple tooth AlGaN/GaN HEMT on SiC substrate: A novel structure for high-power applications

    Science.gov (United States)

    Ghaffari, Majid; Orouji, Ali A.; Valinataj, Mojtaba

    2017-12-01

    In this paper, a AlGaN/AlN/GaN/SiC High Electron Mobility Transistor (HEMT) to reduce the electric field is suggested. The main idea of this work is to improve the Direct Current (DC) and Radio Frequency (RF) properties of device by modifying the depletion region in the channel. The proposed structure consists of a floating metal like a comb with triple tooth which is located in the space between the gate and drain and inside the buffer layer. We called the proposed structure as triple tooth HEMT (TT-HEMT). The RF and DC characteristics of the proposed structure are studied using numerical simulations. The breakdown voltage ( V BR ) increases to 169.5 V for the proposed structure in comparison with 103 V for the conventional HEMT (C-HEMT) due to the modified electric field distribution in the channel of the TT-HEMT structure. The maximum output power density ( P max ) of the TT-HEMT structure is 60.4% greater than that of the C-HEMT. The optimized results show that the maximum oscillation frequency ( f max ) and cut-off frequency (fT) of the proposed structure improve 111% and 26.5%, respectively compared to the C-HEMT structure. In addition, the maximum available gain (MAG) of the TT-HEMT structure is obtained 8.5 dB higher than that of the C-HEMT structure at the frequency of 40 GHz. The optimal results show that whatever the number of teeth on metal increases, the depletion region in the channel is modified more and the breakdown voltage increases, as well. Besides, the output power density ( P max ) is improved with the increasing number of teeth on metal (N). This characteristic is also true, for the cut-off frequency ( f T ), the maximum oscillation frequency ( f max ) and the maximum available gain (MAG) of the proposed structure. However, the drain current ( I D ) of the proposed structure is reduced.

  14. Sub-millimeter-Wave Equivalent Circuit Model for External Parasitics in Double-Finger HEMT Topologies

    Science.gov (United States)

    Karisan, Yasir; Caglayan, Cosan; Sertel, Kubilay

    2018-02-01

    We present a novel distributed equivalent circuit that incorporates a three-way-coupled transmission line to accurately capture the external parasitics of double-finger high electron mobility transistor (HEMT) topologies up to 750 GHz. A six-step systematic parameter extraction procedure is used to determine the equivalent circuit elements for a representative device layout. The accuracy of the proposed approach is validated in the 90-750 GHz band through comparisons between measured data (via non-contact probing) and full-wave simulations, as well as the equivalent circuit response. Subsequently, a semi-distributed active device model is incorporated into the proposed parasitic circuit to demonstrate that the three-way-coupled transmission line model effectively predicts the adverse effect of parasitic components on the sub-mmW performance in an amplifier setting.

  15. Structural characterisation of GaAlN/GaN HEMT heterostructures

    International Nuclear Information System (INIS)

    Sarazin, N.; Durand, O.; Magis, M.; Di Forte Poisson, M.-A.; Di Persio, J.

    2006-01-01

    (GaN/GaAlN/GaN)//Al 2 O 3 (00.1) HEMT heterostructures have been studied by X-ray scattering techniques, transmission electron microscopy and atomic force microscopy. X-ray reflectometry has been used to determine with a high accuracy both the individual layer thicknesses and the interfacial roughness, in spite of the weak electronic density contrast between layers. From the Fourier inversion method and using a simulation software, the roughness of the interface corresponding to the two-dimensional electron gas location has been determined equal to 0.5 nm. Both high resolution X-ray diffraction and transmission electron microscopy experiments have shown the excellent crystallinity of the heterostructures. Finally, the surface morphology has been inferred using atomic force microscopy experiments

  16. The use of HEMTs in multiplexing large arrays of high impedance LTDs

    International Nuclear Information System (INIS)

    Yates, S.J.C.; Benoit, A.; Jin, Y.; Camus, Ph.; Cavanna, A.; Durand, T.; Etienne, B.; Gennser, U.; Gremion, E.; Hoffmann, C.; Leclercq, S.; Ulysse, Ch.

    2006-01-01

    The use of a multiplexing system in close proximity to the detectors simplifies the electronics associated with large arrays of Low Temperature Detectors (LTDs). Here, we report the demonstration of an array of Quantum-Point-Contact High-Electron-Mobility-Transistors (QPC-HEMTs) down to 100mK used to time multiplex the signal from 8 simulated high impedance LTDs (∼10MΩ) to an individual amplifier. Capacitors in parallel with the individual LTDs integrate the signal between measurements so giving a quasi-DC measurement of the LTDs. With the high impedance of the LTD this acts as a filter which counter acts the aliasing of the Johnson noise of the LTD associated with the time-multiplexing technique

  17. Analytical high frequency GaN HEMT model for noise simulations

    Science.gov (United States)

    Eshetu Muhea, Wondwosen; Mulugeta Yigletu, Fetene; Lazaro, Antonio; Iñiguez, Benjamin

    2017-12-01

    A compact high frequency model for AlGaN/GaN HEMT device valid for noise simulations is presented in this paper. The model is developed based on active transmission line approach and linear two port noise theory that makes it applicable for quasi static as well as non-quasi static device operation. The effects of channel length modulation and velocity saturation are discussed. Moreover, the effect of the gate leakage current on the noise performance of the device is investigated. It is shown that there is an apparent increase in noise generated in the device due to the gate current related shot noise. The common noise figures of merit for HFET are calculated and verified with experimental data.

  18. Small-signal model parameter extraction for AlGaN/GaN HEMT

    Science.gov (United States)

    Le, Yu; Yingkui, Zheng; Sheng, Zhang; Lei, Pang; Ke, Wei; Xiaohua, Ma

    2016-03-01

    A new 22-element small signal equivalent circuit model for the AlGaN/GaN high electron mobility transistor (HEMT) is presented. Compared with the traditional equivalent circuit model, the gate forward and breakdown conductions (G gsf and G gdf) are introduced into the new model to characterize the gate leakage current. Additionally, for the new gate-connected field plate and the source-connected field plate of the device, an improved method for extracting the parasitic capacitances is proposed, which can be applied to the small-signal extraction for an asymmetric device. To verify the model, S-parameters are obtained from the modeling and measurements. The good agreement between the measured and the simulated results indicate that this model is accurate, stable and comparatively clear in physical significance.

  19. Field plate structural optimization for enhancing the power gain of GaN-based HEMTs

    Science.gov (United States)

    Zhang, Kai; Cao, Meng-Yi; Lei, Xiao-Yi; Zhao, Sheng-Lei; Yang, Li-Yuan; Zheng, Xue-Feng; Ma, Xiao-Hua; Hao, Yue

    2013-09-01

    A novel source-connected field plate structure, featuring the same photolithography mask as the gate electrode, is proposed as an improvement over the conventional field plate (FP) techniques to enhance the frequency performance in GaN-based HEMTs. The influences of the field plate on frequency and breakdown performance are investigated simultaneously by using a two-dimensional physics-based simulation. Compared with the conventional T-gate structures with a field plate length of 1.2 μm, this field plate structure can induce the small signal power gain at 10 GHz to increase by 5-9.5 dB, which depends on the distance between source FP and dramatically shortened gate FP. This technique minimizes the parasitic capacitances, especially the gate-to-drain capacitance, showing a substantial potential for millimeter-wave, high power applications.

  20. Field plate structural optimization for enhancing the power gain of GaN-based HEMTs

    International Nuclear Information System (INIS)

    Zhang Kai; Cao Meng-Yi; Lei Xiao-Yi; Zhao Sheng-Lei; Yang Li-Yuan; Zheng Xue-Feng; Ma Xiao-Hua; Hao Yue

    2013-01-01

    A novel source-connected field plate structure, featuring the same photolithography mask as the gate electrode, is proposed as an improvement over the conventional field plate (FP) techniques to enhance the frequency performance in GaN-based HEMTs. The influences of the field plate on frequency and breakdown performance are investigated simultaneously by using a two-dimensional physics-based simulation. Compared with the conventional T-gate structures with a field plate length of 1.2 μm, this field plate structure can induce the small signal power gain at 10 GHz to increase by 5-9.5 dB, which depends on the distance between source FP and dramatically shortened gate FP. This technique minimizes the parasitic capacitances, especially the gate-to-drain capacitance, showing a substantial potential for millimeter-wave, high power applications. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. Small-signal model parameter extraction for AlGaN/GaN HEMT

    International Nuclear Information System (INIS)

    Yu Le; Zhang Sheng; Ma Xiaohua; Zheng Yingkui; Pang Lei; Wei Ke

    2016-01-01

    A new 22-element small signal equivalent circuit model for the AlGaN/GaN high electron mobility transistor (HEMT) is presented. Compared with the traditional equivalent circuit model, the gate forward and breakdown conductions (G gsf and G gdf ) are introduced into the new model to characterize the gate leakage current. Additionally, for the new gate-connected field plate and the source-connected field plate of the device, an improved method for extracting the parasitic capacitances is proposed, which can be applied to the small-signal extraction for an asymmetric device. To verify the model, S-parameters are obtained from the modeling and measurements. The good agreement between the measured and the simulated results indicate that this model is accurate, stable and comparatively clear in physical significance. (paper)

  2. Multibias and thermal behavior of microwave GaN and GaAs based HEMTs

    Science.gov (United States)

    Alim, Mohammad A.; Rezazadeh, Ali A.; Gaquiere, Christophe

    2016-12-01

    Multibias and thermal characterizations on 0.25 μm × (2 × 100) μm AlGaN/GaN/SiC HEMT and 0.5 μm × (2 × 100) μm AlGaAs/InGaAs pseudomorphic HEMT have carried out for the first time. Two competitive device technologies are investigated with the variations of bias and temperature in order to afford a detailed realization of their potentialities. The main finding includes the self heating effect in the GaN device, zero temperature coefficient points at the drain current and transconductance in the GaAs device. The thermal resistance RTH of 7.1, 8.2 and 9.4 °C mm/W for the GaN device was estimated at 25, 75 and 150 °C respectively which are consistent with those found in the open literature. The temperature trend of the threshold voltage VT, Schottky barrier height ϕb, sheet charge densities of two dimensional electron gas ns, and capacitance under the gate Cg are exactly opposite in the two devices; whereas the knee voltage Vk, on resistance Ron, and series resistance Rseries are shows similar trend. The multi-bias and thermal behavior of the output current Ids, output conductance gds, transconductance gm, cut-off frequency ft, maximum frequency fmax, effective velocity of electron, veff and field dependent mobility, μ demonstrates a great potential of GaN device. These results provide some valuable insights for technology of preference for future and current applications.

  3. Moral is political Notions of ideal citizenship in Lie Kim Hok’s Hikajat Khonghoetjoe

    Directory of Open Access Journals (Sweden)

    Evi Sutrisno

    2017-04-01

    Full Text Available This paper argues that the Hikajat Khonghoetjoe (The life story of Confucius, written by Lie Kim Hok in 1897, is a medium to propose modern ideas of flexible subjectivity, cosmopolitanism, active citizenship and the concepts of good governance to the Chinese Peranakans who experienced political and racial discrimination under Dutch colonization. Using the figure of Confucius, Lie aimed to cultivate virtuous subjects who apply their faith and morality in political sphere. He intended to raise political awareness and rights among the Chinese as colonial subjects and to valorize their bargaining power with the Dutch colonial government. By introducing Confucianism, Lie proposed that the Chinese reconnect themselves with China as an alternative patronage which could subvert White supremacy. Instead of using sources in Chinese, Lie translated the biography of Confucius from the European texts. In crafting his story, Lie applied conglomerate authorship, a technique commonly practised by Malay authors. It allowed him to select, combine and appropriate the source texts. To justify that Confucius' virtue and his teaching were superb and are applicable to contemporary life, Lie borrowed and emphasized European writers’ high appraisal of Confucianism, instead of using his own arguments and opinions. I call this writing technique “indirect agency”.

  4. Kim Wŏn-haeng’s Intellectual Influences on Hong Tae-yong: The Case of Relations between

    Directory of Open Access Journals (Sweden)

    Login Lok-yin Law

    2015-08-01

    Full Text Available In the 18th century Chosŏn (1392-1910, some scholars, such as Hong Tae-yong (1731-1783 advocated that Chosŏn should learn the advantages of the Qing (1644-1912 society to reform the social structure and government of Chosŏn. The school of these advocates has been known as Pukhak by historians. The intellectual factors of the school of Pukhak’s formation and development have been overlooked by the academia of Chosŏn intellectual history. In fact, Pukhak was closely related to the idea of the school of Nakhak which believed that nature of things was equivalent to humans. Kim Wŏn-haeng, was one of the supporters of Nakhak and Hong Tae-yong was one of the students of Kim. Hong’s thought and writing exposed that his thought was profoundly influenced by Kim Wŏn-haeng. Hong was deemed to be the first prominent scholar of the Pukhak School during the 18th century Chosŏn. Hong and other scholars of Pukhak advocated learning the new knowledge from Qing China even though it was a barbarian society. Therefore, this paper will investigate the intellectual relationships between Hong Tae-yong and Kim Wŏn-haeng to reveal how intellectuals of Nakhak shaped the formation of Pukhak School and exposed the idea of learning from Qing China.

  5. "Sundiata, Lion King of Mali." Adapted by Kim Hines, Featuring Griot Alhaji Papa Susso, Cue Sheet for Students.

    Science.gov (United States)

    Freeman, Aakhu TuahNera

    This performance guide is designed for teachers to use with students before and after a performance of "Sundiata: Lion King of Mali," adapted by Kim Hines and featuring Griot Alhaji Papa Susso. The guide, called a "Cuesheet," contains seven activity sheets for use in class, addressing: (1) Sundiata: Man & Myth (discusses…

  6. Language and Family Dispersion: North Korean Linguist Kim Su-gyŏng and the Korean War

    Directory of Open Access Journals (Sweden)

    Ryuta Itagaki

    2017-03-01

    Full Text Available This article analyzes the unpublished memoir of Kim Su-gyŏng (1918–2000, a linguist who was active in North Korea from the mid-1940s until the late 1960s, and situates his account of his experience of the Korean War within the context of his linguistic essays and correspondence. In doing so, the article considers the role that the personal and the social play in language, utilizing Saussure’s theoretical framework, with which Kim himself was well versed. Kim wrote his memoirs in the 1990s to his family, from whom he had become separated during the Korean War and who now lived in Toronto. In this text, he writes in “personal” language that reveals his uncertainty and his feelings for his family, but then immediately negates these feelings through the use of “social” language, which resonates with his interpretation of the linguistic thesis that Josef Stalin developed during the Korean War on language and national identity. For Kim, the relationship between language and nation was not at all self-evident, but something that he idealized in response to the dispersal of his family. By offering a reflexive reading of a memoir written by a North Korean linguist, this article makes a breakthrough in the investigation of North Korean wartime academic history, which has not risen above the level of analyzing articles in the field of linguistics that were published at the time.

  7. The KIM-family protein-tyrosine phosphatases use distinct reversible oxidation intermediates: Intramolecular or intermolecular disulfide bond formation.

    Science.gov (United States)

    Machado, Luciana E S F; Shen, Tun-Li; Page, Rebecca; Peti, Wolfgang

    2017-05-26

    The kinase interaction motif (KIM) family of protein-tyrosine phosphatases (PTPs) includes hematopoietic protein-tyrosine phosphatase (HePTP), striatal-enriched protein-tyrosine phosphatase (STEP), and protein-tyrosine phosphatase receptor type R (PTPRR). KIM-PTPs bind and dephosphorylate mitogen-activated protein kinases (MAPKs) and thereby critically modulate cell proliferation and differentiation. PTP activity can readily be diminished by reactive oxygen species (ROS), e.g. H 2 O 2 , which oxidize the catalytically indispensable active-site cysteine. This initial oxidation generates an unstable sulfenic acid intermediate that is quickly converted into either a sulfinic/sulfonic acid (catalytically dead and irreversible inactivation) or a stable sulfenamide or disulfide bond intermediate (reversible inactivation). Critically, our understanding of ROS-mediated PTP oxidation is not yet sufficient to predict the molecular responses of PTPs to oxidative stress. However, identifying distinct responses will enable novel routes for PTP-selective drug design, important for managing diseases such as cancer and Alzheimer's disease. Therefore, we performed a detailed biochemical and molecular study of all KIM-PTP family members to determine their H 2 O 2 oxidation profiles and identify their reversible inactivation mechanism(s). We show that despite having nearly identical 3D structures and sequences, each KIM-PTP family member has a unique oxidation profile. Furthermore, we also show that whereas STEP and PTPRR stabilize their reversibly oxidized state by forming an intramolecular disulfide bond, HePTP uses an unexpected mechanism, namely, formation of a reversible intermolecular disulfide bond. In summary, despite being closely related, KIM-PTPs significantly differ in oxidation profiles. These findings highlight that oxidation protection is critical when analyzing PTPs, for example, in drug screening. © 2017 by The American Society for Biochemistry and Molecular Biology

  8. A Decade-Bandwidth Distributed Power Amplifier MMIC Using 0.25 μm GaN HEMT Technology

    Directory of Open Access Journals (Sweden)

    Dong-Hwan Shin

    2017-10-01

    Full Text Available This study presents a 2–20 GHz monolithic distributed power amplifier (DPA using a 0.25 μm AlGaN/GaN on SiC high electron mobility transistor (HEMT technology. The gate width of the HEMT was selected after considering the input capacitance of the unit cell that guarantees decade bandwidth. To achieve high output power using small transistors, a 12-stage DPA was designed with a nonuniform drain line impedance to provide optimal output power matching. The maximum operating frequency of the proposed DPA is above 20 GHz, which is higher than those of other DPAs manufactured with the same gate-length process. The measured output power and power-added efficiency of the DPA monolithic microwave integrated circuit (MMIC are 35.3–38.6 dBm and 11.4%–31%, respectively, for 2–20 GHz.

  9. Operational improvement of AlGaN/GaN HEMT on SiC substrate with the amended depletion region

    Science.gov (United States)

    Ghaffari, Majid; Orouji, Ali A.

    2015-11-01

    In this paper, a high performance AlGaN/GaN High Electron Mobility Transistor (HEMT) on SiC substrates is presented to improve the electrical operation with the amended depletion region using a multiple recessed gate (MRG-HEMT). The basic idea is to change the gate depletion region and a better distribution of the electric field in the channel and improve the device breakdown voltage. The proposed gate consists of lower and upper gate to control the channel thickness. Also, the charge of the depletion region will change due to the optimized gate. In addition, a metal between the gate and drain including the horizontal and vertical parts is used to better control the thickness of the channel. The breakdown voltage, maximum output power density, cut-off frequency, maximum oscillation frequency, minimum noise figure, maximum available gain (MAG), and maximum stable gain (MSG) are some parameters for designers which are considered and are improved in this paper.

  10. 100 nm AlSb/InAs HEMT for Ultra-Low-Power Consumption, Low-Noise Applications

    Science.gov (United States)

    Bagumako, Sonia; Desplanque, Ludovic; Wichmann, Nicolas; Bollaert, Sylvain; Danneville, François; Wallart, Xavier

    2014-01-01

    We report on high frequency (HF) and noise performances of AlSb/InAs high electron mobility transistor (HEMT) with 100 nm gate length at room temperature in low-power regime. Extrinsic cut-off frequencies f T/f max of 100/125 GHz together with minimum noise figure NFmin = 0.5 dB and associated gain G ass = 12 dB at 12 GHz have been obtained at drain bias of only 80 mV, corresponding to 4 mW/mm DC power dissipation. This demonstrates the great ability of AlSb/InAs HEMT for high-frequency operation combined with low-noise performances in ultra-low-power regime. PMID:24707193

  11. Temperature dependent DC characterization of InAlN/(AlN)/GaN HEMT for improved reliability

    Science.gov (United States)

    Takhar, K.; Gomes, U. P.; Ranjan, K.; Rathi, S.; Biswas, D.

    2015-02-01

    InxAl1-xN/AlN/GaN HEMT device performance is analysed at various temperatures with the help of physics based 2-D simulation using commercially available BLAZE and GIGA modules from SILVACO. Various material parameters viz. band-gap, low field mobility, density of states, velocity saturation, and substrate thermal conductivity are considered as critical parameters for predicting temperature effect in InxAl1-xN/AlN/GaN HEMT. Reduction in drain current and transconductance has been observed due to the decrease of 2-DEG mobility and effective electron velocity with the increase in temperature. Degradation in cut-off frequency follows the transconductance profile as variation in gate-source/gate-drain capacitances observed very small.

  12. An analytical turn-on power loss model for 650-V GaN eHEMTs

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Shen, Zhan

    2018-01-01

    This paper proposes an improved analytical turn-on power loss model for 650-V GaN eHEMTs. The static characteristics, i.e., the parasitic capacitances and transconductance, are firstly modeled. Then the turn-on process is divided into multiple stages and analyzed in detail; as results, the time-d......-domain solutions to the drain-source voltage and drain current are obtained. Finally, double-pulse tests are conducted to verify the proposed power loss model. This analytical model enables an accurate and fast switching behavior characterization and power loss prediction.......This paper proposes an improved analytical turn-on power loss model for 650-V GaN eHEMTs. The static characteristics, i.e., the parasitic capacitances and transconductance, are firstly modeled. Then the turn-on process is divided into multiple stages and analyzed in detail; as results, the time...

  13. 100 nm AlSb/InAs HEMT for ultra-low-power consumption, low-noise applications.

    Science.gov (United States)

    Gardès, Cyrille; Bagumako, Sonia; Desplanque, Ludovic; Wichmann, Nicolas; Bollaert, Sylvain; Danneville, François; Wallart, Xavier; Roelens, Yannick

    2014-01-01

    We report on high frequency (HF) and noise performances of AlSb/InAs high electron mobility transistor (HEMT) with 100 nm gate length at room temperature in low-power regime. Extrinsic cut-off frequencies fT/f max of 100/125 GHz together with minimum noise figure NF(min) = 0.5 dB and associated gain G(ass) = 12 dB at 12 GHz have been obtained at drain bias of only 80 mV, corresponding to 4 mW/mm DC power dissipation. This demonstrates the great ability of AlSb/InAs HEMT for high-frequency operation combined with low-noise performances in ultra-low-power regime.

  14. 100 nm AlSb/InAs HEMT for Ultra-Low-Power Consumption, Low-Noise Applications

    Directory of Open Access Journals (Sweden)

    Cyrille Gardès

    2014-01-01

    Full Text Available We report on high frequency (HF and noise performances of AlSb/InAs high electron mobility transistor (HEMT with 100 nm gate length at room temperature in low-power regime. Extrinsic cut-off frequencies fT/fmax of 100/125 GHz together with minimum noise figure NFmin=0.5 dB and associated gain Gass=12 dB at 12 GHz have been obtained at drain bias of only 80 mV, corresponding to 4 mW/mm DC power dissipation. This demonstrates the great ability of AlSb/InAs HEMT for high-frequency operation combined with low-noise performances in ultra-low-power regime.

  15. Evaluation and Reliability Assessment of GaN-on-Si MIS-HEMT for Power Switching Applications

    OpenAIRE

    Chou, Po-Chien; Chen, Szu-Hao; Hsieh, Ting-En; Cheng, Stone; Chang, Edward; del Alamo, Jesus A

    2016-01-01

    This paper reports an extensive analysis of the physical mechanisms responsible for the failure of GaN-based metal–insulator–semiconductor (MIS) high electron mobility transistors (HEMTs). When stressed under high applied electric fields, the traps at the dielectric/III-N barrier interface and inside the III-N barrier cause an increase in dynamic on-resistance and a shift of threshold voltage, which might affect the long term stability of these devices. More detailed investigations are needed...

  16. An AlGaN/GaN HEMT with enhanced breakdown and a near-zero breakdown voltage temperature coefficient

    Science.gov (United States)

    Xie, Gang; Tang, Cen; Wang, Tao; Guo, Qing; Zhang, Bo; Sheng, Kuang; Wai, Tung Ng

    2013-02-01

    An AlGaN/GaN high-electron mobility transistor (HEMT) with a novel source-connected air-bridge field plate (AFP) is experimentally verified. The device features a metal field plate that jumps from the source over the gate region and lands between the gate and drain. When compared to a similar size HEMT device with a conventional field plate (CFP) structure, the AFP not only minimizes the parasitic gate to source capacitance, but also exhibits higher OFF-state breakdown voltage and one order of magnitude lower drain leakage current. In a device with a gate to drain distance of 6 μm and a gate length of 0.8 μm, three times higher forward blocking voltage of 375 V was obtained at VGS = -5 V. In contrast, a similar sized HEMT with a CFP can only achieve a breakdown voltage no higher than 125 V using this process, regardless of device dimensions. Moreover, a temperature coefficient of 0 V/K for the breakdown voltage is observed. However, devices without a field plate (no FP) and with an optimized conventional field plate (CFP) exhibit breakdown voltage temperature coefficients of -0.113 V/K and -0.065 V/K, respectively.

  17. An AlGaN/GaN HEMT with enhanced breakdown and a near-zero breakdown voltage temperature coefficient

    International Nuclear Information System (INIS)

    Xie Gang; Tang Cen; Wang Tao; Guo Qing; Sheng Kuang; Zhang Bo; Ng Wai Tung

    2013-01-01

    An AlGaN/GaN high-electron mobility transistor (HEMT) with a novel source-connected air-bridge field plate (AFP) is experimentally verified. The device features a metal field plate that jumps from the source over the gate region and lands between the gate and drain. When compared to a similar size HEMT device with a conventional field plate (CFP) structure, the AFP not only minimizes the parasitic gate to source capacitance, but also exhibits higher OFF-state breakdown voltage and one order of magnitude lower drain leakage current. In a device with a gate to drain distance of 6 μm and a gate length of 0.8 μm, three times higher forward blocking voltage of 375 V was obtained at V GS = −5 V. In contrast, a similar sized HEMT with a CFP can only achieve a breakdown voltage no higher than 125 V using this process, regardless of device dimensions. Moreover, a temperature coefficient of 0 V/K for the breakdown voltage is observed. However, devices without a field plate (no FP) and with an optimized conventional field plate (CFP) exhibit breakdown voltage temperature coefficients of −0.113 V/K and −0.065 V/K, respectively. (condensed matter: structural, mechanical, and thermal properties)

  18. Highly efficient GaN HEMTs transformer-less single-phase inverter for grid-tied fuel cell

    Science.gov (United States)

    Alatawi, Khaled; Almasoudi, Fahad; Matin, Mohammad

    2017-08-01

    Transformer-less inverters are the most efficient approach to utilize renewable energy sources for grid tied applications. In this paper, a grid-tied fuel cell transformer-less single-phase inverter equipped with GaN HEMTs is proposed. The new topology is derived from conventional H5 inverter. The benefits of using GaN HEMTs are to enable the system to switch at high frequency, which will reduce the size, volume and cost of the system. Moreover, inverter control is designed and proposed to supply real power to the grid and to work as DSTATCOM to mitigate any voltage sag and compensate reactive power in the system. A comparison of the performance of the proposed inverter with Si IGBT and GaN HEMTs was presented to analyze the benefits of using WBG devices. The switching strategy of the new topology creates a new current path which reduces the conduction losses significantly. The analysis of the proposed system was carried out using MATLAB/SIMULINK and PSIM and the results show that the proposed controller improves voltage stability, power quality, mitigates voltage sag and compensates reactive power. Accordingly, the results prove the effectiveness of the system for grid-tied applications.

  19. Evaluation and Reliability Assessment of GaN-on-Si MIS-HEMT for Power Switching Applications

    Directory of Open Access Journals (Sweden)

    Po-Chien Chou

    2017-02-01

    Full Text Available This paper reports an extensive analysis of the physical mechanisms responsible for the failure of GaN-based metal–insulator–semiconductor (MIS high electron mobility transistors (HEMTs. When stressed under high applied electric fields, the traps at the dielectric/III-N barrier interface and inside the III-N barrier cause an increase in dynamic on-resistance and a shift of threshold voltage, which might affect the long term stability of these devices. More detailed investigations are needed to identify epitaxy- or process-related degradation mechanisms and to understand their impact on electrical properties. The present paper proposes a suitable methodology to characterize the degradation and failure mechanisms of GaN MIS-HEMTs subjected to stress under various off-state conditions. There are three major stress conditions that include: VDS = 0 V, off, and off (cascode-connection states. Changes of direct current (DC figures of merit in voltage step-stress experiments are measured, statistics are studied, and correlations are investigated. Hot electron stress produces permanent change which can be attributed to charge trapping phenomena and the generation of deep levels or interface states. The simultaneous generation of interface (and/or bulk and buffer traps can account for the observed degradation modes and mechanisms. These findings provide several critical characteristics to evaluate the electrical reliability of GaN MIS-HEMTs which are borne out by step-stress experiments.

  20. Concept Development of "Nursing Presence": Application of Schwartz-Barcott and Kim's Hybrid Model.

    Science.gov (United States)

    Mohammadipour, Fatemeh; Atashzadeh-Shoorideh, Foroozan; Parvizy, Soroor; Hosseini, Meimanat

    2017-03-01

    Although nursing presence is a foundation for professional nursing practice and has known positive outcomes such as patient satisfaction and recovery; it is not well known. The ambiguity surrounding how to define nursing presence has challenged its evaluation and education. Therefore, in an attempt to discover attributes of this underdeveloped concept and studying it in a new context, concept development is essential. The purpose of this study was to clarify the concept of nursing presence through concept development, to produce a tentative definition of this subjective concept in clinical practice. Concept development was carried out using Schwartz-Barcott and Kim's hybrid model including, theoretical, fieldwork and final analysis phases. First, 29 related articles available on the databases from 1990-2015 were reviewed and analyzed. Then, 22 interviews were conducted with 19 participants, followed with inductive content analysis. At last, an overall definition was performed. Nursing presence can be explained as co-constructed interaction identified by deliberate focus, task-oriented/patient-oriented relationship, accountability, clarification, and ubiquitous participation. Nursing presence requires clinical competence, self-actualization, reciprocating openness, and conducive working environment. Worthwhile communications, balance/recovery, and growth and transcendence are the main consequences of this concept. Co-constructed interaction underscored the value of the nursing presence as an integral component of caring with humanistic and patient-centered approaches. The findings could help clinical nurses have a better understanding of the nursing presence. Findings also can improve educators' and managers' knowledge for developing and conducting appropriate education strategies and caring activities to facilitate the promotion of nursing presence. Copyright © 2017. Published by Elsevier B.V.

  1. "Don't you realize it's Just Her Disguise?" : Performances of femininity by Kim Gordon, Tori Amos and Gillian Welch

    OpenAIRE

    Håkensen, Siv Tonje

    2007-01-01

    Women who perform popular music are also performing gender. This is both because gender can be understood as performance and because musical conventions and styles carry with them assumptions about femininity and masculinity. This thesis concerns three female popular music artists; Kim Gordon of Sonic Youth, Tori Amos and Gillian Welch, and their performances of femininity. As these artists have been presented as or have presented themselves as in some way "authentic", my readings of these ar...

  2. North Korean Leadership Dynamics and Decision-making under Kim Jong-un: A Second Year Assessment

    Science.gov (United States)

    2014-03-01

    Marxist- Leninist model for self -reliance called Juche. It became the principal ideology for politics, economics, national defense, and foreign...Leader Comrade Kim Jong Il in High Esteem Down through Generations. The 90-minute fourth installment of the official documen- tary film series...organization which will manage sports and athletics in North Korea.218 Jang Song-taek was appointed chairman of the com- mission. While the North Korean

  3. Demonstration of an RF front-end based on GaN HEMT technology

    Science.gov (United States)

    Ture, Erdin; Musser, Markus; Hülsmann, Axel; Quay, Rüdiger; Ambacher, Oliver

    2017-05-01

    The effectiveness of the developed front-end on blocking the communication link of a commercial drone vehicle has been demonstrated in this work. A jamming approach has been taken in a broadband fashion by using GaN HEMT technology. Equipped with a modulated-signal generator, a broadband power amplifier, and an omni-directional antenna, the proposed system is capable of producing jamming signals in a very wide frequency range between 0.1 - 3 GHz. The maximum RF output power of the amplifier module has been software-limited to 27 dBm (500 mW), complying to the legal spectral regulations of the 2.4 GHz ISM band. In order to test the proof of concept, a real-world scenario has been prepared in which a commercially-available quadcopter UAV is flown in a controlled environment while the jammer system has been placed in a distance of about 10 m from the drone. It has been proven that the drone of interest can be neutralized as soon as it falls within the range of coverage (˜3 m) which endorses the promising potential of the broadband jamming approach.

  4. Impact of the lateral width of the gate recess on the DC and RF characteristics of InAlAs/InGaAs HEMTs

    International Nuclear Information System (INIS)

    Zhong Yinghui; Zhang Yuming; Wang Xiantai; Su Yongbo; Cao Yuxiong; Jin Zhi; Liu Xinyu

    2012-01-01

    We fabricated 88 nm gate-length InP-based InAlAs/InGaAs high electron mobility transistors (HEMTs) with a current gain cutoff frequency of 100 GHz and a maximum oscillation frequency of 185 GHz. The characteristics of HEMTs with side-etched region lengths (L side ) of 300, 412 and 1070 nm were analyzed. With the increase in L side , the kink effect became notable in the DC characteristics, which resulted from the surface state and the effect of impact ionization. The kink effect was qualitatively explained through energy band diagrams, and then eased off by reducing the L side . Meanwhile, the L side dependence of the radio frequency characteristics, which were influenced by the parasitic capacitance, as well as the parasitic resistance of the source and drain, was studied. This work will be of great importance in fabricating high-performance InP HEMTs. (semiconductor devices)

  5. Investigation of the Performance of HEMT-Based NO, NO2 and NH3 Exhaust Gas Sensors for Automotive Antipollution Systems

    Directory of Open Access Journals (Sweden)

    Yacine Halfaya

    2016-02-01

    Full Text Available We report improved sensitivity to NO, NO2 and NH3 gas with specially-designed AlGaN/GaN high electron mobility transistors (HEMT that are suitable for operation in the harsh environment of diesel exhaust systems. The gate of the HEMT device is functionalized using a Pt catalyst for gas detection. We found that the performance of the sensors is enhanced at a temperature of 600 °C, and the measured sensitivity to 900 ppm-NO, 900 ppm-NO 2 and 15 ppm-NH 3 is 24%, 38.5% and 33%, respectively, at 600 °C. We also report dynamic response times as fast as 1 s for these three gases. Together, these results indicate that HEMT sensors could be used in a harsh environment with the ability to control an anti-pollution system in real time.

  6. A kidney injury molecule-1 (Kim-1) gene reporter in a mouse artificial chromosome: the responsiveness to cisplatin toxicity in immortalized mouse kidney S3 cells.

    Science.gov (United States)

    Kokura, Kenji; Kuromi, Yasushi; Endo, Takeshi; Anzai, Naohiko; Kazuki, Yasuhiro; Oshimura, Mitsuo; Ohbayashi, Tetsuya

    2016-10-01

    Kidney injury molecule-1 (Kim-1) has been validated as a urinary biomarker for acute and chronic renal damage. The expression of Kim-1 mRNA is also activated by acute kidney injury induced by cisplatin in rodents and humans. To date, the measurement of Kim-1 expression has not fully allowed the detection of in vitro cisplatin nephrotoxicity in immortalized culture cells, such as human kidney-2 cells and immortalized proximal tubular epithelial cells. We measured the augmentation of Kim-1 mRNA expression after the addition of cisplatin using immortalized S3 cells established from the kidneys of transgenic mice harboring temperature-sensitive large T antigen from Simian virus 40. A mouse Kim-1 gene luciferase reporter in conjunction with an Hprt gene reporter detected cisplatin-induced nephrotoxicity in S3 cells. These two reporter genes were contained in a mouse artificial chromosome, and two luciferases that emitted different wavelengths were used to monitor the respective gene expression. However, the Kim-1 reporter gene failed to respond to cisplatin in A9 fibroblast cells that contained the same reporter mouse artificial chromosome, suggesting cell type-specificity for activation of the reporter. We report the feasibility of measuring in vitro cisplatin nephrotoxicity using a Kim-1 reporter gene in S3 cells. © 2016 The Authors. The Journal of Gene Medicine Published by John Wiley & Sons, Ltd.

  7. Lactobacillus curvatus WiKim38 isolated from kimchi induces IL-10 production in dendritic cells and alleviates DSS-induced colitis in mice.

    Science.gov (United States)

    Jo, Sung-Gang; Noh, Eui-Jeong; Lee, Jun-Young; Kim, Green; Choi, Joo-Hee; Lee, Mo-Eun; Song, Jung-Hee; Chang, Ji-Yoon; Park, Jong-Hwan

    2016-07-01

    Probiotics such as lactobacilli and bifidobacteria have healthpromoting effects by immune modulation. In the present study, we examined the immunomodulatory properties of Lactobacillus curvatus WiKim38, which was newly isolated from baechu (Chinese cabbage) kimchi. The ability of L. curvatus WiKim38 to induce cytokine production in bone marrow-derived dendritic cells (BMDCs) was determined by enzyme-linked immunosorbent assay. To evaluate the molecular mechanisms underlying L. curvatus Wikim38-mediated IL-10 production, Western blot analyses and inhibitor assays were performed. Moreover, the in vivo anti-inflammatory effects of L. curvatus WiKim38 were examined in a dextran sodium sulfate (DSS)-induced colitis mouse model. L. curvatus WiKim38 induced significantly higher levels of IL-10 in BMDCs compared with that induced by LPS. NF-κB and ERK were activated by L. curvatus WiKim38, and an inhibitor assay revealed that these pathways were required for L. curvatus WiKim38-induced production of IL-10 in BMDCs. An in vivo experiment showed that oral administration of L. curvatus WiKim38 increased the survival rate of mice with DSS-induced colitis and improved clinical signs and histopathological severity in colon tissues. Taken together, these results indicate that L. curvatus Wikim38 may have health-promoting effects via immune modulation, and may thus be applicable for therapy of various inflammatory diseases.

  8. Effect of Field Plate on the RF Performance of AlGaN/GaN HEMT Devices

    Science.gov (United States)

    Chiang, Che-Yang; Hsu, Heng-Tung; Chang, Edward Yi

    This paper examines the effect of the field plate structure on the RF performance of AlGaN/GaN High Electron Mobility Transistor (HEMT) devices. While the field plate structure helps to increase the breakdown voltage of the device through modulating the electric field locally, it induces additional feedback capacitance from drain to gate. Such feedback capacitors may impact the overall RF performance of the device especially at high frequencies. Systematic investigations on the small signal as well as power performance as functions of the drain biases are presented.

  9. Physical modeling and optimization of a GaN HEMT design with a field plate structure for high frequency application

    OpenAIRE

    Cucak, Dejana; Vasic, Miroslav; García, Oscar; Bouvier, Yann; Oliver Ramírez, Jesús Angel; Alou Cervera, Pedro; Cobos Márquez, José Antonio; Wang, Ashu; Martin Horcajo, Sara; Romero Rojo, Fátima; Calle Gómez, Fernando

    2014-01-01

    Abstract: In this paper, physical modeling of a GaN HEMT with a field plate structure is proposed, with the objective of providing the connection between the physical design parameters of the device (geometry, Al mole fraction, type of the field plate, etc) and on-resistance together with parasitic capacitances of the device. In this way, it is possible to optimize the design of a switching device for a particular application, which in our case is a high frequency DC DC converter for Envel...

  10. Simultaneous measurement of temperature, stress, and electric field in GaN HEMTs with micro-Raman spectroscopy

    Science.gov (United States)

    Bagnall, Kevin R.; Moore, Elizabeth A.; Badescu, Stefan C.; Zhang, Lenan; Wang, Evelyn N.

    2017-11-01

    As semiconductor devices based on silicon reach their intrinsic material limits, compound semiconductors, such as gallium nitride (GaN), are gaining increasing interest for high performance, solid-state transistor applications. Unfortunately, higher voltage, current, and/or power levels in GaN high electron mobility transistors (HEMTs) often result in elevated device temperatures, degraded performance, and shorter lifetimes. Although micro-Raman spectroscopy has become one of the most popular techniques for measuring localized temperature rise in GaN HEMTs for reliability assessment, decoupling the effects of temperature, mechanical stress, and electric field on the optical phonon frequencies measured by micro-Raman spectroscopy is challenging. In this work, we demonstrate the simultaneous measurement of temperature rise, inverse piezoelectric stress, thermoelastic stress, and vertical electric field via micro-Raman spectroscopy from the shifts of the E2 (high), A1 longitudinal optical (LO), and E2 (low) optical phonon frequencies in wurtzite GaN. We also validate experimentally that the pinched OFF state as the unpowered reference accurately measures the temperature rise by removing the effect of the vertical electric field on the Raman spectrum and that the vertical electric field is approximately the same whether the channel is open or closed. Our experimental results are in good quantitative agreement with a 3D electro-thermo-mechanical model of the HEMT we tested and indicate that the GaN buffer acts as a semi-insulating, p-type material due to the presence of deep acceptors in the lower half of the bandgap. This implementation of micro-Raman spectroscopy offers an exciting opportunity to simultaneously probe thermal, mechanical, and electrical phenomena in semiconductor devices under bias, providing unique insight into the complex physics that describes device behavior and reliability. Although GaN HEMTs have been specifically used in this study to

  11. Note: Ultra-high frequency ultra-low dc power consumption HEMT amplifier for quantum measurements in millikelvin temperature range.

    Science.gov (United States)

    Korolev, A M; Shnyrkov, V I; Shulga, V M

    2011-01-01

    We have presented theory and experimentally demonstrated an efficient method for drastically reducing the power consumption of the rf/microwave amplifiers based on HEMT in unsaturated dc regime. Conceptual one-stage 10 dB-gain amplifier showed submicrowatt level of the power consumption (0.95 μW at frequency of 0.5 GHz) when cooled down to 300 mK. Proposed technique has a great potential to design the readout amplifiers for ultra-deep-cooled cryoelectronic quantum devices.

  12. Characterization and Modeling I(V of the Gate Schottky Structures HEMTs Ni/Au/AlInN/GaN

    Directory of Open Access Journals (Sweden)

    N. Benyahya

    2014-05-01

    Full Text Available In this paper, we have studied the Schottky contact of Ni/Au/AlInN/GaN HEMTs. The current–voltage Igs (Vgs of Ni/Au/AlInN/GaN structures were investigated at room temperature. The electrical parameters such as ideality factor (2.3, barrier height (0.72 eV and series resistance (33 W were evaluated from I(V data, the threshold voltage (-2.42 V, the 2D gas density (1.35 ´ 1013 cm-2 and barrier height (0.94 eV were evaluated from C(V data.

  13. An analytical turn-on power loss model for 650-V GaN eHEMTs

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Shen, Zhan

    2018-01-01

    -domain solutions to the drain-source voltage and drain current are obtained. Finally, double-pulse tests are conducted to verify the proposed power loss model. This analytical model enables an accurate and fast switching behavior characterization and power loss prediction.......This paper proposes an improved analytical turn-on power loss model for 650-V GaN eHEMTs. The static characteristics, i.e., the parasitic capacitances and transconductance, are firstly modeled. Then the turn-on process is divided into multiple stages and analyzed in detail; as results, the time...

  14. Teasing out the compressed education debates in contemporary South Korea: Media portrayal of figure skater Yuna Kim

    OpenAIRE

    Kim, Hye Jin

    2013-01-01

    In this thesis, I argue that the heated debates about South Korea’s education policy consist of problems that arise from different genres of discourses that in turn belong to different historical moments and education values. I engage in a media discourse analysis of the reportage on South Korean international sport celebrity Yuna Kim that highlight the key education debates currently taking place in South Korea. First, I deal with the neologism umchinttal (my mom’s friend’s daughter) as an i...

  15. Report on visit from Prof. Kim Lutzen: Friday, 6 November 1998, Korolinska Institute (dept of nursing Stockholm, Sweden

    Directory of Open Access Journals (Sweden)

    Kim Lutzen

    1999-10-01

    Full Text Available Prof. Kim Lutzen contacted the Department of Advanced Nursing Sciences, Unisa, via the Department's Web Page. Prof. Lutzen is the Chair of the Department of Nursing, which offers undergraduate, master and doctoral programmes. This Department of Nursing is situated within the Karolinska Institute, which comprises 29 Departments of Health Sciences, including a number of Medical Departments, Dentistry, Occupational Therapy, Physiotherapy, and Nursing. Prof. Lutzen emphasised that there is no Swedish phrase similar to "nursing science", consequently this t e n seems to be somewhat unfamiliar to the Swedish nurses. *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.

  16. The complete larval development of Eurypanopeus canalensis Abele and Kim, 1989 (Crustacea: Brachyura: Panopeidae described from laboratory reared material

    Directory of Open Access Journals (Sweden)

    Marcelo U. García-Guerrero

    2005-09-01

    Full Text Available The estuarine panopeid crab Eurypanopeus canalensis Abele and Kim, 1989, is an eastern tropical Pacific species with a known distribution from the southeastern Gulf of California, Mexico, to Panama. Its complete larval development is fully described and illustrated from laboratory-reared material. The four zoeal stages and the megalopa are compared with two congeneric species from the West Atlantic, E. abbreviatus (Stimpson, 1860 and E. depressus (Smith, 1869. The main differences between larvae of E. canalensis and those of these two species include telson setation and the presence/absence of a stout hook-like spine in the megalopae cheliped ischium.

  17. Muusikauudised : Lu : k ja Jäääär koos laval. Britney Spears tegutseb. Lenny Kravitz ja Mick Jagger. Kim Wilde

    Index Scriptorium Estoniae

    2001-01-01

    Tartus Sõbra majas toimunud kontserdist. Videost "Britney: The video". Heliplaatidest: "Britney", "The Best of Pink Floyd", "Lenny", Mick Jagger "Goddess In The Doorway", "The Very Best Of Kim Wilde"

  18. Validation Study of Kim's Sham Needle by Measuring Facial Temperature: An N-of-1 Randomized Double-Blind Placebo-Controlled Clinical Trial

    Directory of Open Access Journals (Sweden)

    Sanghun Lee

    2012-01-01

    Full Text Available Introduction. In 2008, Kim's sham needle was developed to improve the quality of double-blinded studies. The aim of this study is to validate Kim's sham needle by measuring facial temperature. Methods. We designed “N-of-1” trials involving 7 smokers. One session was composed of 2 stimulations separated by a 2 h washout period. Six sessions were applied daily for all subjects. Infrared thermal imaging was used to examine the effects of acupuncture (HT8, KI2 on facial temperature following smoking-induced decrease. Results. All subjects demonstrated decreased temperatures after sham needle treatment, but 5 of the 7 subjects showed increased temperatures after real needle treatment. 6 of the 7 subjects showed a significant difference (P<0.05 between treatments with real and sham needles. Thus, the physiological stimulation of Kim's sham needle is different from that of a real needle, suggesting that Kim's sham needle is a potential inactive control intervention.

  19. Quantum ballistic transistor and low noise HEMT for cryo-electronics lower than 4.2 K; Transistor balistique quantique et HEMT bas-bruit pour la cryoelectronique inferieure a 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Gremion, E

    2008-01-15

    Next generations of cryo-detectors, widely used in physics of particles and physics of universe, will need in the future high-performance cryo-electronics less noisy and closer to the detector. Within this context, this work investigates properties of two dimensional electron gas GaAlAs/GaAs by studying two components, quantum point contact (QPC) and high electron mobility transistor (HEMT). Thanks to quantized conductance steps in QPC, we have realized a quantum ballistic transistor (voltage gain higher than 1), a new component useful for cryo-electronics thanks to its operating temperature and weak power consumption (about 1 nW). Moreover, the very low capacity of this component leads to promising performances for multiplexing low temperature bolometer dedicated to millimetric astronomy. The second study focused on HEMT with very high quality 2DEG. At 4.2 K, a voltage gain higher than 20 can be obtained with a very low power dissipation of less than 100 {mu}W. Under the above experimental conditions, an equivalent input voltage noise of 1.2 nV/{radical}(Hz) at 1 kHz and 0.12 nV/{radical}(Hz) at 100 kHz has been reached. According to the Hooge formula, these noise performances are get by increasing gate capacity estimated to 60 pF. (author)

  20. Influence of mesa edge capacitance on frequency behavior of millimeter-wave AlGaN/GaN HEMTs

    Science.gov (United States)

    Du, Jiangfeng; Wang, Kang; Liu, Yong; Bai, Zhiyuan; Liu, Yang; Feng, Zhihong; Dun, Shaobo; Yu, Qi

    2017-03-01

    The influence of mesa edge capacitance on the frequency characteristics of AlGaN/GaN HEMTs with 90 nm gate length was studied in this paper. To extract mesa edge capacitances, a small-signal equivalent circuit model considering mesa edge capacitances was provided. Based on the model, the intrinsic gate capacitances of AlGaN/GaN HEMTs with 2 × 20 μm, 2 × 30 μm, 2 × 40 μm, and 2 × 50 μm gate widths were extracted, respectively. Through linear fitting along gate width for the extracted results and simulations, 8.06 fF/μm2 of mesa edge capacitances at Vgs = -4.5 V and Vds = 8 V in the devices with 2 × 20 μm gate width was obtained, which can be about 33.2% of the total gate capacitance. Mesa edge capacitances results in a significant drop of current-gain cut-off frequency (fT), and the effect is more serious in the shorter gate length devices.

  1. Interface Si donor control to improve dynamic performance of AlGaN/GaN MIS-HEMTs

    Directory of Open Access Journals (Sweden)

    Liang Song

    2017-12-01

    Full Text Available In this letter, we have studied the performance of AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs with different interface Si donor incorporation which is tuned during the deposition process of LPCVD-SiNx which is adopted as gate dielectric and passivation layer. Current collapse of the MIS-HEMTs without field plate is suppressed more effectively by increasing the SiH2Cl2/NH3 flow ratio and the normalized dynamic on-resistance (RON is reduced two orders magnitude after off-state VDS stress of 600 V for 10 ms. Through interface characterization, we have found that the interface deep-level traps distribution with high Si donor incorporation by increasing the SiH2Cl2/NH3 flow ratio is lowered. It’s indicated that the Si donors are most likely to fill and screen the deep-level traps at the interface resulting in the suppression of slow trapping process and the virtual gate effect. Although the Si donor incorporation brings about the increase of gate leakage current (IGS, no clear degradation of breakdown voltage can be seen by choosing appropriate SiH2Cl2/NH3 flow ratio.

  2. Barrier layer engineering: Performance evaluation of E-mode InGaN/AlGaN/GaN HEMT

    Science.gov (United States)

    Majumdar, Shubhankar; Das, S.; Biswas, D.

    2015-08-01

    Impact on DC characteristics of InGaN/AlGaN/GaN HEMT due to variation in the hetero-structure parameters i.e. molar fraction of Al and thickness of AlGaN barrier layer is presented in this paper. Gate controllability over the channel is dependent on barrier layer thickness, and molar fraction has an impact on band offset and 2DEG, which further affects the current. HEMT device that is simulated in SILVACO has InGaN cap layer of 2 nm thickness with 15% In molar fraction, variation of Al percentage and thickness of the AlGaN barrier layer are taken as 15-45% and 5-20nm, respectively. A tremendous change in threshold voltage (Vth), maximum transconductance (Gmmax) and subthreshold swing is found due to variation in hetero-structure parameter of barrier layer and the values are typically 1.3-0.1 V, 0.6-0.44 S/mm and 75-135 mV/dec respectively.

  3. Quantum ballistic transistor and low noise HEMT for cryo-electronics lower than 4.2 K

    International Nuclear Information System (INIS)

    Gremion, E.

    2008-01-01

    Next generations of cryo-detectors, widely used in physics of particles and physics of universe, will need in the future high-performance cryo-electronics less noisy and closer to the detector. Within this context, this work investigates properties of two dimensional electron gas GaAlAs/GaAs by studying two components, quantum point contact (QPC) and high electron mobility transistor (HEMT). Thanks to quantized conductance steps in QPC, we have realized a quantum ballistic transistor (voltage gain higher than 1), a new component useful for cryo-electronics thanks to its operating temperature and weak power consumption (about 1 nW). Moreover, the very low capacity of this component leads to promising performances for multiplexing low temperature bolometer dedicated to millimetric astronomy. The second study focused on HEMT with very high quality 2DEG. At 4.2 K, a voltage gain higher than 20 can be obtained with a very low power dissipation of less than 100 μW. Under the above experimental conditions, an equivalent input voltage noise of 1.2 nV/√(Hz) at 1 kHz and 0.12 nV/√(Hz) at 100 kHz has been reached. According to the Hooge formula, these noise performances are get by increasing gate capacity estimated to 60 pF. (author)

  4. Low k-dielectric benzocyclobutane encapsulated AlGaN/GaN HEMTs with Improved off-state breakdown voltage

    Science.gov (United States)

    Jesudas Anand, Mulagumoottil; Ng, Geok Ing; Arulkumaran, Subramaniam; Ranjan, Kumud; Vicknesh, Sahmuganathan; Ang, Kian Siong

    2015-03-01

    The impact of low-k dielectric benzocyclobutane (BCB) encapsulation on the electrical performance and structural stability of AlGaN/GaN HEMTs on Si were investigated. After BCB encapsulation, devices exhibited no degradation in their drain current density, extrinsic transconductance and small signal microwave performances. The curing temperature (280 °C) of BCB layer had no influence on the device electrical performances. Compared to devices without BCB encapsulation, the BCB encapsulated devices achieved ∼2 orders of magnitude lower gate- and drain-leakage current. An order of magnitude lower surface leakage current was also observed by BCB encapsulation between the two adjacent mesas. Due to the reduction of leakage currents, ∼2-times increase of OFF-state breakdown voltage was observed. In addition, the 9-µm-thick BCB encapsulation layer also helps to have structurally stable air bridges. This work demonstrates the low-k dielectric BCB as a viable solution for the complete encapsulation of GaN HEMTs and ICs.

  5. Helen Kim as New Woman and Collaborator: A Comprehensive Assessment of Korean Collaboration under Japanese Colonial Rule

    Directory of Open Access Journals (Sweden)

    AhRan Ellie Bae

    2017-02-01

    Full Text Available Although almost seventy years has passed since Korea's liberation from Japanese rule, the issue of collaboration still haunts Korea today. Attempts to resolve this issue have tended to focus attention on the traitorous actions of "collaborators" without considering the gray areas that surround their actions such as the circumstances that influenced the accused to commit their alleged traitorous acts and the intentions that drove their decisions. Helen Kim, as a "new woman" and an educator, valued the necessity of providing education for women. Yet, her efforts to realize this goal, to the contrary, forced her into actions that would later be used to construct a reputation as a Japanese collaborator. Korea's nationalist historiography has a tendency to polarize this issue by categorizing a "collaborator" as either a traitor or a patriot. However, when we take a closer look at these collaborators' lives, we discover that most collaboration happened in gray areas where it is often difficult to clearly draw a line between treason and collaboration. Helen Kim's case suggests that the issue of collaboration cannot be fully explained by nationalist historiography's framework and we must give attention to these gray areas. Through her story I hope to complicate the issue of collaboration by raising questions that address the gray areas that surround the actions of "collaborators." In doing so, I hope to challenge the nationalist historiography's propensity to oversimplify this issue and present a more nuanced understanding of it.

  6. Endogenous Tim-1 (Kim-1) promotes T-cell responses and cell-mediated injury in experimental crescentic glomerulonephritis.

    Science.gov (United States)

    Nozaki, Yuji; Nikolic-Paterson, David J; Snelgrove, Sarah L; Akiba, Hisaya; Yagita, Hideo; Holdsworth, Stephen R; Kitching, A Richard

    2012-05-01

    The T-cell immunoglobulin mucin 1 (Tim-1) modulates CD4(+) T-cell responses and is also expressed by damaged proximal tubules in the kidney where it is known as kidney injury molecule-1 (Kim-1). We sought to define the role of endogenous Tim-1 in experimental T-cell-mediated glomerulonephritis induced by sheep anti-mouse glomerular basement membrane globulin acting as a planted foreign antigen. Tim-1 is expressed by infiltrating activated CD4(+) cells in this model, and we studied the effects of an inhibitory anti-Tim-1 antibody (RMT1-10) on immune responses and glomerular disease. Crescentic glomerulonephritis, proliferative injury, and leukocyte accumulation were attenuated following treatment with anti-Tim-1 antibodies, but interstitial foxp3(+) cell accumulation and interleukin-10 mRNA were increased. T-cell proliferation and apoptosis decreased in the immune system along with a selective reduction in Th1 and Th17 cellular responses both in the immune system and within the kidney. The urinary excretion and renal expression of Kim-1 was reduced by anti-Tim-1 antibodies reflecting diminished interstitial injury. The effects of anti-Tim-1 antibodies were not apparent in the early phase of renal injury, when the immune response to sheep globulin was developing. Thus, endogenous Tim-1 promotes Th1 and Th17 nephritogenic immune responses and its neutralization reduces renal injury while limiting inflammation in cell-mediated glomerulonephritis.

  7. Viscous flux flow velocity and stress distribution in the Kim model of a long rectangular slab superconductor

    Science.gov (United States)

    Yang, Yong; Chai, Xueguang

    2018-05-01

    When a bulk superconductor endures the magnetization process, enormous mechanical stresses are imposed on the bulk, which often leads to cracking. In the present work, we aim to resolve the viscous flux flow velocity υ 0/w, i.e. υ 0 (because w is a constant) and the stress distribution in a long rectangular slab superconductor for the decreasing external magnetic field (B a ) after zero-field cooling (ZFC) and field cooling (FC) using the Kim model and viscous flux flow equation simultaneously. The viscous flux flow velocity υ 0/w and the magnetic field B* at which the body forces point away in all of the slab volumes during B a reduction, are determined by both B a and the decreasing rate (db a /dt) of the external magnetic field normalized by the full penetration field B p . In previous studies, υ 0/w obtained by the Bean model with viscous flux flow is only determined by db a /dt, and the field B* that is derived only from the Kim model is a positive constant when the maximum external magnetic field is chosen. This means that the findings in this paper have more physical contents than the previous results. The field B* stress changing with decreasing field B a after ZFC if B* ≤ 0. The effect of db a /dt on the stress is significant in the cases of both ZFC and FC.

  8. AlGaN/GaN MIS-HEMT using NbAlO dielectric layer grown by atomic layer deposition

    Science.gov (United States)

    Bi, Zhi-Wei; Feng, Qian; Hao, Yue; Wang, Dang-Hui; Ma, Xiao-Hua; Zhang, Jin-Cheng; Quan, Si; Xu, Sheng-Rui

    2010-07-01

    We present an AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT) with an NbAlO high-k dielectric deposited by atomic layer deposition (ALD). Surface morphology of samples are observed by atomic force microscopy (AFM), indicating that the ALD NbAlO has an excellent-property surface. Moreover, the sharp transition from depletion to accumulation in capacitance-voltage (C-V)curse of MIS-HEMT demonstrates the high quality bulk and interface properties of NbAlO on AlGaN. The fabricated MIS-HEMT with a gate length of 0.5 μm exhibits a maximum drain current of 960 mA/mm, and the reverse gate leakage current is almost 3 orders of magnitude lower than that of reference HEMT. Based on the improved direct-current operation, the NbAlO can be considered to be a potential gate oxide comparable to other dielectric insulators.

  9. AlGaN/GaN MIS-HEMT using NbAlO dielectric layer grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Zhi-Wei, Bi; Qian, Feng; Yue, Hao; Xiao-Hua, Ma; Jin-Cheng, Zhang; Si, Quan; Sheng-Rui, Xu; Dang-Hui, Wang

    2010-01-01

    We present an AlGaN/GaN metal–insulator–semiconductor high electron mobility transistor (MIS-HEMT) with an NbAlO high-k dielectric deposited by atomic layer deposition (ALD). Surface morphology of samples are observed by atomic force microscopy (AFM), indicating that the ALD NbAlO has an excellent-property surface. Moreover, the sharp transition from depletion to accumulation in capacitance–voltage (C–V)curse of MIS-HEMT demonstrates the high quality bulk and interface properties of NbAlO on AlGaN. The fabricated MIS-HEMT with a gate length of 0.5 μm exhibits a maximum drain current of 960 mA/mm, and the reverse gate leakage current is almost 3 orders of magnitude lower than that of reference HEMT. Based on the improved direct-current operation, the NbAlO can be considered to be a potential gate oxide comparable to other dielectric insulators. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  10. Improvement of breakdown characteristics of an AlGaN/GaN HEMT with a U-type gate foot for millimeter-wave power application

    International Nuclear Information System (INIS)

    Kong Xin; Wei Ke; Liu Guo-Guo; Liu Xin-Yu

    2012-01-01

    In this study, the physics-based device simulation tool Silvaco ATLAS is used to characterize the electrical properties of an AlGaN/GaN high electron mobility transistor (HEMT) with a U-type gate foot. The U-gate AlGaN/GaN HEMT mainly features a gradually changed sidewall angle, which effectively mitigates the electric field in the channel, thus obtaining enhanced off-state breakdown characteristics. At the same time, only a small additional gate capacitance and decreased gate resistance ensure excellent RF characteristics for the U-gate device. U-gate AlGaN/GaN HEMTs are feasible through adjusting the etching conditions of an inductively coupled plasma system, without introducing any extra process steps. The simulation results are confirmed by experimental measurements. These features indicate that U-gate AlGaN/GaN HEMTs might be promising candidates for use in millimeter-wave power applications. (interdisciplinary physics and related areas of science and technology)

  11. Investigations of AlGaN/GaN MOS-HEMT with Al2O3 deposition by ultrasonic spray pyrolysis method

    Science.gov (United States)

    Chou, Bo-Yi; Hsu, Wei-Chou; Liu, Han-Yin; Lee, Ching-Sung; Wu, Yu-Sheng; Sun, Wen-Ching; Wei, Sung-Yen; Yu, Sheng-Min; Chiang, Meng-Hsueh

    2015-01-01

    This work investigates Al2O3/AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) grown on SiC substrate by using the non-vacuum ultrasonic spray pyrolysis deposition (USPD) method. The Al2O3 was deposited as gate dielectric and surface passivation simultaneously to effectively suppress gate leakage current, enhance output current density, reduce RF drain current collapse, and improve temperature-dependent stabilities performance. The present MOS-HEMT design has shown improved device performances with respect to a Schottky-gate HEMT, including drain-source saturation current density at zero gate bias (IDSS: 337.6 mA mm-1 → 462.9 mA mm-1), gate-voltage swing (GVS: 1.55 V → 2.92 V), two-terminal gate-drain breakdown voltage (BVGD: -103.8 V → -183.5 V), unity-gain cut-off frequency (fT: 11.3 GHz → 17.7 GHz), maximum oscillation frequency (fmax: 14.2 GHz → 19.1 GHz), and power added effective (P.A.E.: 25.1% → 43.6%). The bias conditions for measuring fT and fmax of the studied MOS-HEMT (Schottky-gate HEMT) are VGS = -2.5 (-2) V and VDS = 7 V. The corresponding VGS and VDS biases are -2.5 (-2) V and 15 V for measuring the P.A.E. characteristic. Moreover, small capacitance-voltage (C-V) hysteresis is obtained in the Al2O3-MOS structure by using USPD. Temperature-dependent characteristics of the present designs at 300-480 K are also studied.

  12. Investigations of AlGaN/GaN MOS-HEMT with Al2O3 deposition by ultrasonic spray pyrolysis method

    International Nuclear Information System (INIS)

    Chou, Bo-Yi; Hsu, Wei-Chou; Liu, Han-Yin; Wu, Yu-Sheng; Lee, Ching-Sung; Sun, Wen-Ching; Wei, Sung-Yen; Yu, Sheng-Min; Chiang, Meng-Hsueh

    2015-01-01

    This work investigates Al 2 O 3 /AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) grown on SiC substrate by using the non-vacuum ultrasonic spray pyrolysis deposition (USPD) method. The Al 2 O 3 was deposited as gate dielectric and surface passivation simultaneously to effectively suppress gate leakage current, enhance output current density, reduce RF drain current collapse, and improve temperature-dependent stabilities performance. The present MOS-HEMT design has shown improved device performances with respect to a Schottky-gate HEMT, including drain-source saturation current density at zero gate bias (I DSS : 337.6 mA mm −1  → 462.9 mA mm −1 ), gate-voltage swing (GVS: 1.55 V → 2.92 V), two-terminal gate-drain breakdown voltage (BV GD : −103.8 V → −183.5 V), unity-gain cut-off frequency (f T : 11.3 GHz → 17.7 GHz), maximum oscillation frequency (f max : 14.2 GHz → 19.1 GHz), and power added effective (P.A.E.: 25.1% → 43.6%). The bias conditions for measuring f T and f max of the studied MOS-HEMT (Schottky-gate HEMT) are V GS  = −2.5 (−2) V and V DS  = 7 V. The corresponding V GS and V DS biases are −2.5 (−2) V and 15 V for measuring the P.A.E. characteristic. Moreover, small capacitance-voltage (C–V) hysteresis is obtained in the Al 2 O 3 -MOS structure by using USPD. Temperature-dependent characteristics of the present designs at 300–480 K are also studied. (paper)

  13. Expression of kidney injury molecule-1 (Kim-1) in relation to necrosis and apoptosis during the early stages of Cd-induced proximal tubule injury

    International Nuclear Information System (INIS)

    Prozialeck, Walter C.; Edwards, Joshua R.; Lamar, Peter C.; Liu, Jie; Vaidya, Vishal S.; Bonventre, Joseph V.

    2009-01-01

    Cadmium (Cd) is a nephrotoxic industrial and environmental pollutant that causes a generalized dysfunction of the proximal tubule. Kim-1 is a transmembrane glycoprotein that is normally not detectable in non-injured kidney, but is up-regulated and shed into the urine during the early stages of Cd-induced proximal tubule injury. The objective of the present study was to examine the relationship between the Cd-induced increase in Kim-1 expression and the onset of necrotic and apoptotic cell death in the proximal tubule. Adult male Sprague-Dawley rats were treated with 0.6 mg (5.36 μmol) Cd/kg, subcutaneously, 5 days per week for up to 12 weeks. Urine samples were analyzed for levels of Kim-1 and the enzymatic markers of cell death, lactate dehydrogenase (LDH) and alpha-glutathione-S-transferase (α-GST). In addition, necrotic cells were specifically labeled by perfusing the kidneys in situ with ethidium homodimer using a procedure that has been recently developed and validated in the Prozialeck laboratory. Cryosections of the kidneys were also processed for the immunofluorescent visualization of Kim-1 and the identification of apoptotic cells by TUNEL labeling. Results showed that significant levels of Kim-1 began to appear in the urine after 6 weeks of Cd treatment, whereas the levels of total protein, α-GST and LDH were not increased until 8-12 weeks. Results of immunofluorescence labeling studies showed that after 6 weeks and 12 weeks, Kim-1 was expressed in the epithelial cells of the proximal tubule, but that there was no increase in the number of necrotic cells, and only a modest increase in the number of apoptotic cells at 12 weeks. These results indicate that the Cd-induced increase in Kim-1 expression occurs before the onset of necrosis and at a point where there is only a modest level of apoptosis in the proximal tubule.

  14. Cooling Simulation and Thermal Abuse Modeling of Lithium-Ion Batteries Using the Newman, Tiedemann, Gu, and Kim (NTGK) Model

    DEFF Research Database (Denmark)

    Saeed Madani, Seyed; Swierczynski, Maciej Jozef; Kær, Søren Knudsen

    2017-01-01

    This paper gives insight into the cooling simulation and thermal abuse modeling of lithium-ion batteries by ANSYS FLUENT. Cooling strategies are important issues in the thermal management of lithium-ion battery systems, and it is essential to investigate them attentively in order to maintain...... the functioning temperature of batteries within an optimum range. The high temperature is able not only to decrease the efficiency of batteries but also may lead to the thermal runaway. To comprehend further, the thermal abuse behavior of lithium-ion batteries based on The Newman, Tiedemann, Gu, and Kim (NTGK......) model has been implemented in ANSYS FLUENT software. The results show that to achieve an optimum energy consumption for battery cooling, a minimum value of average heat transfer coefficient can be selected in order to keep the functioning temperature of batteries within an optimum range....

  15. L-Arginine attenuates the ethylene glycol induced urolithiasis in ininephrectomized hypertensive rats: role of KIM-1, NGAL, and NOs.

    Science.gov (United States)

    Kandhare, Amit D; Patil, Mithun V K; Bodhankar, Subhash L

    2015-05-01

    Ethylene glycol (EG) exposure caused formation of calcium oxalate crystal that led to renal failure, which is associated with higher prevalence of hypertension. L-Arginine is known to have an antioxidant and nephro-protective potential. To evaluate the effect of L-arginine against EG-induced urolithiasis in uninephrectomized hypertensive rats. Uninephrectomized male Wistar rats (180-200 g) were used to induce urinary calculi through oral administration of EG (0.75%) in distilled water. Rats were treated with either distilled water (10 mg/kg, p.o.) or telmisartan (10 mg/kg, p.o.) or Cystone (500 mg/kg, p.o.) or L-arginine (250, 500, and 1000 mg/kg, p.o.) for 28 days. Various hemodynamic, biochemical, molecular, and histological parameters were assessed in kidney and heart. Rats treated with L-arginine (500 and 1000 mg/kg) significantly restored altered relative organ weight, urine output, urine density, urinary pH, and water intake. EG-induced alterations in electrocardiographic (QRS interval, HR, and ST height) and hemodynamic (SBP, DBP, MABP, and LVEDP) abnormalities were significantly restored by L-arginine (500 and 1000 mg/kg) treatment. It also significantly restored alteration in serum and urine biochemical parameters induced by EG. The elevated oxido-nitrosative stress was also significantly decreased by L-arginine (500 and 1000 mg/kg) treatment. It also significantly down-regulated EG-induced up-regulated renal KIM-1, NGAL, eNOS, and iNOs mRNA expressions. Histological aberrations induced in the renal and cardiac tissues were also ameliorated by l-arginine treatment. L-Arginine exerts its nephro- and cardio-protective potential in EG-induced urolithiasis in uninephrectomized hypertensive rats via modulation of KIM-1, NGAL, eNOS, and iNOs mRNA expression.

  16. A comparison of the 60Co gamma radiation hardness, breakdown characteristics and the effect of SiNx capping on InAlN and AlGaN HEMTs for space applications

    International Nuclear Information System (INIS)

    Smith, M D; Parbrook, P J; O’Mahony, D; Vitobello, F; Muschitiello, M; Costantino, A; Barnes, A R

    2016-01-01

    Electrical performance and stability of InAlN and AlGaN high electron mobility transistors (HEMTs) subjected 9.1 mrad of 60 Co gamma radiation and off-state voltage step-stressing until breakdown are reported. Comparison with commercially available production-level AlGaN HEMT devices, which showed negligible drift in DC performance throughout all experiments, suggests degradation mechanisms must be managed and suppressed through development of advanced epitaxial and surface passivation techniques in order to fully exploit the robustness of the III-nitride material system. Of the research level devices without dielectric layer surface capping, InAlN HEMTs exhibited the greater stability compared with AlGaN under off-state bias stressing and gamma irradiation in terms of their DC characteristics, although AlGaN HEMTs had significantly higher breakdown voltages. The effect of plasma-enhanced chemical vapour deposition SiN x surface capping is explored, highlighting the sensitivity of InAlN HEMT performance to surface passivation techniques. InAlN–SiN x HEMTs suffered more from trap related degradation than AlGaN–SiN x devices in terms of radiation hardness and step-stress characteristics, attributed to an increased capturing of carriers in traps at the InAlN/SiN x interface. (paper)

  17. Improvement of RF performance for AlGaN/GaN HEMT by using a cavity structure

    Science.gov (United States)

    Wang, Wen; Yu, Xinxin; Zhou, Jianjun; Chen, Dunjun; Zhang, Kai; Kong, Cen; Lu, Haiyan; Kong, Yuechan; Li, Zhonghui; Chen, Tangsheng

    2016-12-01

    A novel method of improving RF performance for AlGaN/GaN HEMT by introducing a cavity structure under the gate-head of the T-shaped gate is proposed, which can effectively reduce the parasitic gate capacitance. The device with cavity structure presents quite similar DC characteristics with the conventional device without cavity, including a maximum drain current density of 1.16 A/mm, a peak transconductance of 424 mS/mm and a slightly degraded two-terminal breakdown voltage of 29 V. However, in comparison with the device without cavity, the device with cavity presents the significant improvements in small signal characteristics, with the fT increasing from 60 GHz to 84 GHz and the fmax increasing from 93 GHz to 104 GHz.

  18. SEMICONDUCTOR DEVICES: Improvements to the extraction of an AlGaN/GaN HEMT small-signal model

    Science.gov (United States)

    Yan, Pu; Lei, Pang; Liang, Wang; Xiaojuan, Chen; Chengzhan, Li; Xinyu, Liu

    2009-12-01

    The accurate extraction of AlGaN/GaN HEMT small-signal models, which is an important step in large-signal modeling, can exactly reflect the microwave performance of the physical structure of the device. A new method of extracting the parasitic elements is presented, and an open dummy structure is introduced to obtain the parasitic capacitances. With a Schottky resistor in the gate, a new method is developed to extract Rg. In order to characterize the changes of the depletion region under various drain voltages, the drain delay factor is involved in the output conductance of the device. Compared to the traditional method, the fitting of S 11 and S 22 is improved, and fT and fmax can be better predicted. The validity of the proposed method is verified with excellent correlation between the measured and simulated S -parameters in the range of 0.1 to 26.1 GHz.

  19. A novel AlGaN/GaN HEMT with a p-layer in the barrier

    Science.gov (United States)

    Razavi, S. M.; Zahiri, S. H.; Hosseini, S. E.

    2013-12-01

    The potential impact of gallium-nitride (GaN) high electron mobility transistor (HEMT) with a p-layer in the barrier is reported. We investigate the device performance focusing on short channel effects, gate-drain capacitance, electric field, breakdown voltage, DC output conductance (go), drain current, DC trans-conductance (gm) and sub-threshold slope using two-dimensional and two-carrier device simulations. Our simulation results reveal that the proposed structure reduces the short channel effects, gate-drain capacitance, sub-threshold slope and go compared to the conventional and T-gate structures. Also this new structure reduces the peak electric field at the gate corner near the drain and consequently increases the breakdown voltage significantly. Increasing p-layer length (Lp) and thickness (Tp), improves the breakdown voltage, short channel effects, gate-drain capacitance and go.

  20. Improvements to the extraction of an AlGaN/GaN HEMT small-signal model

    International Nuclear Information System (INIS)

    Pu Yan; Pang Lei; Wang Liang; Chen Xiaojuan; Li Chengzhan; Liu Xinyu

    2009-01-01

    The accurate extraction of AlGaN/GaN HEMT small-signal models, which is an important step in large-signal modeling, can exactly reflect the microwave performance of the physical structure of the device. A new method of extracting the parasitic elements is presented, and an open dummy structure is introduced to obtain the parasitic capacitances. With a Schottky resistor in the gate, a new method is developed to extract R g . In order to characterize the changes of the depletion region under various drain voltages, the drain delay factor is involved in the output conductance of the device. Compared to the traditional method, the fitting of S 11 and S 22 is improved, and f T and f max can be better predicted. The validity of the proposed method is verified with excellent correlation between the measured and simulated S-parameters in the range of 0.1 to 26.1 GHz. (semiconductor devices)

  1. Remote PECVD silicon nitride films with improved electrical properties for GaAs P-HEMT passivation

    CERN Document Server

    Sohn, M K; Kim, K H; Yang, S G; Seo, K S

    1998-01-01

    In order to obtain thin silicon nitride films with excellent electrical and mechanical properties, we employed RPECVD (Remote Plasma Enhanced Chemical Vapor Deposition) process which produces less plasma-induced damage than the conventional PECVD. Through the optical and electrical measurements of the deposited films, we optimized the various RPECVD process parameters. The optimized silicon nitride films showed excellent characteristics such as small etch rate (approx 33 A/min by 7:1 BHF), high breakdown field (>9 MV/cm), and low compressive stress (approx 3.3x10 sup 9 dyne/cm sup 2). We successfully applied thin RPECVD silicon nitride films to the surface passivation of GaAs pseudomorphic high electron mobility transistors (P-HEMTs) with negligible degradations in DC and RF characteristics.

  2. Monte Carlo study of the noise performance of isolated-gate InAs/AlSb HEMTs

    International Nuclear Information System (INIS)

    Rodilla, H; Moschetti, G; Grahn, J; González, T; Mateos, J

    2012-01-01

    In this work, the extrinsic dynamic behavior and noise performance of a 225 nm isolated-gate InAs/AlSb high electron mobility transistor (HEMT) have been studied by means of Monte Carlo simulations. A very good agreement with experimental results has been achieved for f T . Discrepancies between experimental and simulated f max have been observed and attributed to the experimental frequency dispersion of g d and C ds . The simulations of the intrinsic and extrinsic noise parameters indicate an excellent performance for this device (F min = 0.3 dB at 10 GHz) even if we confirm that the presence of the native oxide under the gate induces a significant decrease in f T and f max of around 20%, together with an increase of noise figure and noise resistance

  3. A comparison of Roche Kinetic Interaction of Microparticles in Solution (KIMS) assay for cannabinoids and GC-MS analysis for 11-nor-9-carboxy-delta9-tetrahydrocannabinol.

    Science.gov (United States)

    Lyons, T P; Okano, C K; Kuhnle, J A; Bruins, M R; Darwin, W D; Moolchan, E T; Huestis, M A

    2001-10-01

    In this study, we investigated the effectiveness of the Roche Kinetic Interaction of Microparticles in Solution (KIMS) screening assay for cannabinoid metabolites. Urine specimens (N = 1689) were collected during elimination of cannabinoids from 25 subjects with a history of marijuana use. Specimens were analyzed concurrently for cannabinoid metabolites by a customized Department of Defense (DOD) cannabinoid KIMS kit (50-ng/mL cutoff) and for 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THC-COOH) by GC-MS (15-ng/mL cutoff). As compared to GC-MS results, the sensitivity, specificity, and efficiency of the KIMS assay were 69.7%, 99.8%, and 88.6%, respectively. Many of the false-negative results had GC-MS concentrations between 15 and 26 ng/mL (N = 151). The cannabinoid screening results for the DOD samples tested by the laboratory during the same 8-month period were also evaluated. The linear regression analyses of GC-MS results in the 15-50 ng/mL range and KIMS data resulted in regression coefficients of 0.689 for the research specimens and 0.546 for DOD specimens. The results suggest that the KIMS cannabinoid screening assay is deficient in detecting positives around the cutoff (15-25 ng/mL THC-COOH). This limitation of the KIMS cannabinoid screening method compromises the identification of true positive specimens, therefore reducing the effectiveness of the assay. The success of the DOD program is dependent on sensitive and specific screening assays; the high prevalence of false-negative cannabinoid results compromises the program's primary objective of drug deterrence.

  4. KIM, Steady-State Transport for Fixed Source in 2-D Thermal Reactor by Monte-Carlo

    International Nuclear Information System (INIS)

    Cupini, E.; De Matteis, A.; Simonini, R.

    1980-01-01

    1 - Description of problem or function: KIM (K-infinite Monte Carlo) is a program which solves the steady-state linear transport equation for a fixed-source problem (or, by successive fixed-source runs, for the eigenvalue problem) in a two-dimensional infinite thermal reactor lattice. The main quantities computed in some broad energy groups are the following: - Fluxes and cross sections averaged over the region (i.e. a space portion that can be unconnected but contains everywhere the same homogeneous material), grouping of regions, the whole element. - Average absorption and fission rates per nuclide. - Average flux, absorption and production distributions versus energy. 2 - Method of solution: Monte Carlo simulation is used by tracing particle histories from fission birth down through the resonance region until absorption in the thermal range. The program is organised in three sections for fast, epithermal and thermal simulation, respectively; each section implements a particular model for both numerical techniques and cross section representation (energy groups in the fast section, groups or resonance parameters in the epithermal section, points in the thermal section). During slowing down (energy above 1 eV) nuclei are considered as stationary, with the exception of some resonance nuclei whose spacing between resonances is much greater than the resonance width. The Doppler broadening of s-wave resonances of these nuclides is taken into account by computing cross sections at the current neutron energy and at the temperature of the nucleus hit. During thermalization (energy below 1 eV) the thermal motion of some nuclides is also considered, by exploiting scattering kernels provided by the library for light water, heavy water and oxygen at several temperatures. KIM includes splitting and Russian roulette. A characteristic feature of the program is its approach to the lattice geometry. In fact, besides the usual continuous treatment of the geometry using the well

  5. Distorsión no lineal en un transmisor polar debida a la característica Ron(VDD) del dispositivo GaN HEMT

    OpenAIRE

    Marante Torres, Reinel; García García, José Ángel; Cabral, Pedro Miguel da Silva; Pedro, Jose Carlos Esteves Duarte

    2009-01-01

    In this paper, the possible impact of RF switching device ON resistance variation with drain supply voltage, Ron(VDD) characteristic, on polar transmitter distortion is considered. Using Pulsed I/V measurement results over a 15 W GaN HEMT, the deviation in the Vdd-to-AM modulation profile is estimated. System-level calculations, in the presence of gateto- drain capacitance contribution to carrier feedthrough, allow the evaluation of the secondary role of this dispersion effect.

  6. A new assessment method of pHEMT models by comparing relative errors of drain current and its derivatives up to the third order

    Science.gov (United States)

    Dobeš, Josef; Grábner, Martin; Puričer, Pavel; Vejražka, František; Míchal, Jan; Popp, Jakub

    2017-05-01

    Nowadays, there exist relatively precise pHEMT models available for computer-aided design, and they are frequently compared to each other. However, such comparisons are mostly based on absolute errors of drain-current equations and their derivatives. In the paper, a novel method is suggested based on relative root-mean-square errors of both drain current and its derivatives up to the third order. Moreover, the relative errors are subsequently relativized to the best model in each category to further clarify obtained accuracies of both drain current and its derivatives. Furthermore, one our older and two newly suggested models are also included in comparison with the traditionally precise Ahmed, TOM-2 and Materka ones. The assessment is performed using measured characteristics of a pHEMT operating up to 110 GHz. Finally, a usability of the proposed models including the higher-order derivatives is illustrated using s-parameters analysis and measurement at more operating points as well as computation and measurement of IP3 points of a low-noise amplifier of a multi-constellation satellite navigation receiver with ATF-54143 pHEMT.

  7. Investigation of the fabrication processes of AlGaN/AlN/GaN HEMTs with in situ Si{sub 3}N{sub 4} passivation

    Energy Technology Data Exchange (ETDEWEB)

    Tomosh, K. N., E-mail: sky77781@mail.ru; Pavlov, A. Yu.; Pavlov, V. Yu.; Khabibullin, R. A.; Arutyunyan, S. S.; Maltsev, P. P. [Russian Academy of Sciences, Institute of Ultra-High-Frequency Semiconductor Electronics (Russian Federation)

    2016-10-15

    The optimum mode of the in situ plasma-chemical etching of a Si{sub 3}N{sub 4} passivating layer in C{sub 3}F{sub 8}/O{sub 2} medium is chosen for the case of fabricating AlGaN/AlN/GaN HEMTs. It is found that a bias of 40–50 V at a high-frequency electrode provides anisotropic etching of the insulator through a resist mask and introduces no appreciable radiation-induced defects upon overetching of the insulator films in the region of gate-metallization formation. To estimate the effect of in situ Si{sub 3}N{sub 4} growth together with the heterostructure in one process on the AlGaN/AlN/GaN HEMT characteristics, transistors with gates without the insulator and with gates through Si{sub 3}N{sub 4} slits are fabricated. The highest drain current of the AlGaN/AlN/GaN HEMT at 0 V at the gate is shown to be 1.5 times higher in the presence of Si{sub 3}N{sub 4} than without it.

  8. Current-Voltage-Temperature (I-V-T Characteristics of Schottky-Gate of the Structures AlGaN/GaN HEMTs

    Directory of Open Access Journals (Sweden)

    M. MOSTEFAOUI

    2014-05-01

    Full Text Available In this study, the forward bias current-voltage-temperature (I-V-T characteristics of (Mo/Au–AlGaN/GaN high electron mobility transistors (HEMTs have been investigated over the temperature range of 100-450K. The barrier height (Fb, ideality factor (n, series resistance (Rs and shunt resistance (Rp of (Mo/Au–AlGaN/GaN HEMTs have been calculated from their experimental forward bias current–voltage-temperature (I-V-T. The capacitance–voltage (C–V of (Au/Mo- AlGaN/GaN HEMTs were investigated at room temperature. The doping concentration (Nd and the bi- dimensional sheet carrier density (ns were evaluated from C–V data. The experimental results show that all forward bias semilogarithmic I-V curves for the different temperatures have a nearly common cross point at a certain bias voltage, even with finite series resistance (Rs. We found that the value of Fb and Rs increases by cons n and Rp decreases with increasing temperature. The values of Nss obtained by taking into account the Rs are about one order lower than those obtained without considering the Rs.

  9. 30 nm T-gate enhancement-mode InAlN/AlN/GaN HEMT on SiC substrates for future high power RF applications

    Science.gov (United States)

    Murugapandiyan, P.; Ravimaran, S.; William, J.

    2017-08-01

    The DC and RF performance of 30 nm gate length enhancement mode (E-mode) InAlN/AlN/GaN high electron mobility transistor (HEMT) on SiC substrate with heavily doped source and drain region have been investigated using the Synopsys TCAD tool. The proposed device has the features of a recessed T-gate structure, InGaN back barrier and Al2O3 passivated device surface. The proposed HEMT exhibits a maximum drain current density of 2.1 A/mm, transconductance {g}{{m}} of 1050 mS/mm, current gain cut-off frequency {f}{{t}} of 350 GHz and power gain cut-off frequency {f}\\max of 340 GHz. At room temperature the measured carrier mobility (μ), sheet charge carrier density ({n}{{s}}) and breakdown voltage are 1580 cm2/(V \\cdot s), 1.9× {10}13 {{cm}}-2, and 10.7 V respectively. The superlatives of the proposed HEMTs are bewitching competitor or future sub-millimeter wave high power RF VLSI circuit applications.

  10. Effect of self-heating on electrical characteristics of AlGaN/ GaN HEMT on Si (111) substrate

    Science.gov (United States)

    Nigam, Adarsh; Bhat, Thirumaleshwara N.; Rajamani, Saravanan; Dolmanan, Surani Bin; Tripathy, Sudhiranjan; Kumar, Mahesh

    2017-08-01

    In order to study the effect of self-heating of AlGaN/ GaN high electron mobility transistors (HEMTs) characteristics fabricated on Si(111) substrate, simulations of 2DEG temperature on different drain voltages have been carried out by Sentaurus TCAD simulator tool. Prior to the electrical direct-current (DC) characteristics studies, structural properties of the HEMT structures were examined by scanning transmission electron microscopy. The comparative analysis of simulation and experimental data provided sheet carrier concentration, mobility, surface traps, electron density at 2DEG by considering factors such as high field saturation, tunneling and recombination models. Mobility, surface trap concentration and contact resistance were obtained by TCAD simulation and found out to be ˜1270cm2/Vs, ˜2×1013 cm-2 and ˜0.2 Ω.mm, respectively, which are in agreement with the experimental results. Consequently, simulated current-voltage characteristics of HEMTs are in good agreement with experimental results. The present simulator tool can be used to design new device structures for III-nitride technology.

  11. The trouble with halos: invited commentary on Kim, S., & Harris, P. L. (2014). Children prefer to learn from mind-readers. British Journal of Developmental Psychology.

    Science.gov (United States)

    Richert, Rebekah A

    2014-11-01

    This commentary on Kim and Harris (2014) addresses the authors' interpretation of the halo effect, in which 5- to 6-year-old children preferentially agreed with an informant who could read other people's minds, regardless of domain of knowledge. © 2014 The British Psychological Society.

  12. Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Kidney Injury Molecule 1 (KIM1) in patients with diabetic nephropathy: a cross-sectional study and the effects of lisinopril

    DEFF Research Database (Denmark)

    Nielsen, S E; Schjoedt, K J; Astrup, A S

    2010-01-01

    Our aim was to evaluate the markers of tubulointerstitial damage, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule1 (KIM1) in Type 1 diabetic patients with different levels of albuminuria and in control subjects. In addition, the effect of renoprotective treatment...

  13. Reduction of proteinuria in adriamycin-induced nephropathy is associated with reduction of renal kidney injury molecule (Kim-1) over time

    NARCIS (Netherlands)

    Kramer, Andrea B.; van Timmeren, Mirjan M.; Schuurs, Theo A.; Vaidya, Vishal S.; Bonventre, Joseph V.; van Goor, Harry; Navis, Gerjan

    Kramer AB, van Timmeren MM, Schuurs TA, Vaidya VS, Bonventre JV, van Goor H, Navis G. Reduction of proteinuria in adriamycin-induced nephropathy is associated with reduction of renal kidney injury molecule (Kim-1) over time. Am J Physiol Renal Physiol 296: F1136-F1145, 2009. First published February

  14. Understanding internal backgrounds in NaI(Tl) crystals toward a 200 kg array for the KIMS-NaI experiment

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, P.; Adhikari, G.; Oh, S.Y. [Sejong University, Department of Physics, Seoul (Korea, Republic of); Choi, S.; Joo, H.W.; Kim, K.W.; Kim, S.K. [Seoul National University, Department of Physics and Astronomy, Seoul (Korea, Republic of); Ha, C.; Jeon, E.J.; Kang, W.G.; Kim, H.O.; Kim, N.Y.; Lee, H.S.; Lee, J.H.; Lee, M.H.; Leonard, D.S.; Li, J.; Olsen, S.L.; Park, H.K.; Park, K.S.; So, J.H.; Yoon, Y.S. [Institute for Basic Science, Center for Underground Physics, Daejeon (Korea, Republic of); Hahn, I.S. [Ewha Womans University, Department of Science Education, Seoul (Korea, Republic of); Kim, H.J. [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Kim, Y.D. [Sejong University, Department of Physics, Seoul (Korea, Republic of); Institute for Basic Science, Center for Underground Physics, Daejeon (Korea, Republic of); Kim, Y.H. [Institute for Basic Science, Center for Underground Physics, Daejeon (Korea, Republic of); Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Park, H.S. [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2016-04-15

    The Korea Invisible Mass Search (KIMS) collaboration has developed low-background NaI(Tl) crystals that are suitable for the direct detection of WIMP dark matter. Building on experience accumulated during the KIMS-CsI programs, the KIMS-NaI experiment will consist of a 200 kg NaI(Tl) crystal array surrounded by layers of shielding structures and will be operated at the Yangyang underground laboratory. The goal is to provide an unambiguous test of the DAMA/LIBRA annual modulation signature. Measurements of six prototype crystals show progress in the reduction of internal contamination from radioisotopes. Based on our understanding of these measurements, we expect to achieve a background level in the final detector configuration that is less than 1 count/day/keV/kg for recoil energies around 2 keV. The annual modulation sensitivity for the KIMS-NaI experiment shows that an unambiguous 7σ test of the DAMA/LIBRA signature would be possible with a 600 kg year exposure with this system. (orig.)

  15. Anthropocene Knowledge Practices in McKenzie Wark’s Molecular Red and Kim Stanley Robinson’s Aurora

    Directory of Open Access Journals (Sweden)

    Gib Prettyman

    2018-02-01

    Full Text Available Through a close reading of McKenzie Wark’s theoretical treatise 'Molecular Red' (2015 and Kim Stanley Robinson’s novel 'Aurora' (2015, this essay examines how Anthropocene knowledge practices challenge our conceptions of human agency in provocative and potentially productive ways. For example, our knowledge of climate science arises through global material infrastructures. As material components of Anthropocene knowledge practices, these infrastructures reveal the material labors and cyborg structures by means of which our knowledge is produced. Wark sees the heterogenous materiality of Anthropocene knowledge practices as evidence for the value of ‘low theories’ based on a ‘labor point of view.’ At the same time, Anthropocene knowledge practices reveal ‘eco-logical’ complexities and fundamental recognitions of the ‘intra-action’ of entangled matter. These complexities produce very estranged views of human agency. Robinson’s novel highlights the eco-logical implications of contemporary knowledge practices by imagining an interstellar ship that must function as a completely artificial ecosystem for a 170-year voyage to another solar system. The significance of knowledge practices and eco-logical complexity is most evident when failures or crises arise, and 'Aurora' tells the story of many such failures. However, I argue that Robinson’s novel and Wark’s ‘low theory’ ultimately function as hopeful accounts of Anthropocene knowledge practices. Among other things, these practices show the material importance of storytelling and point the way toward more complexly realist theories of human agency.

  16. Concept development of "compassion fatigue" in clinical nurses: Application of Schwartz-Barcott and Kim's hybrid model

    Directory of Open Access Journals (Sweden)

    Mahdieh Sabery

    2017-06-01

    Full Text Available Compassion fatigue is not a new concept in nursing; yet, it is not well known and there is no fixed clear definition of the term. The ambiguity surrounding how to define compassion fatigue has challenged its measurement and evaluation. Thus, any attempt to determine attributes of this underdeveloped concept and studying it in a new socio-cultural context requires concept development. The purpose of this study is to clarify the concept of compassion fatigue through concept development and to produce a vivid and tentative definition of this concept in clinical practice. Concept development was conducted using a three-step hybrid concept analysis including theoretical, fieldwork, and final analysis phases according to Schwartz-Barcott and Kim's method. We reviewed and analyzed 48 articles that met the inclusion criteria. Following, the first author conducted 13 interviews with clinical nurses followed by an inductive content analysis. Finally, a comprehensive definition of compassion fatigue in nurses was attained. Compassion fatigue in nurses can be explained as a cumulative and progressive process of absorption of the patient’s pain and suffering formed from the sympathetic and caring interactions with the patients and their families. The physical, emotional, intellectual, spiritual, social, and organizational consequences of compassion fatigue are so extensive that they threaten the existential integrity of the nurse. Context-based variables (culture, family, and community such as personality features like devotion behaviors and commitment towards the patient, exposure to multiple stressors, organizational challenges, and lack of self-care are factors associated with an increased risk of compassion fatigue. Concept development of compassion fatigue is the first step in the protection of nurses against the destructive consequences of compassion fatigue and to improve quality of care.

  17. A NIM (Nuclear Instrumentation Module) system conjugated with optional input for pHEMT amplifier for beta and gamma spectroscopy; Um sistema de modulos NIM conjugados com entrada opcional por amplificador pHEMT para espectroscopia beta e gama

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, Barbara; Lüdke, Everton, E-mail: barbarakonradmev@gmail.com, E-mail: eludke@smail.ufsm.br [Universidade Federal de Santa Maria (LAE/UFSM), RS (Brazil). Lab. de Astrofisica e Eletronica

    2014-07-01

    This work presents a high speed NIM module (Nuclear Instrumentation Module) to detect radiation, gamma and muons, as part of a system for natural radiation monitoring and of extraterrestrial origin. The subsystem developed consists of a preamplifier and an integrated SCA (Single Channel Analyzer), including power supplies of ± 12 and ± 24V with derivations of +3.6 and ± 5V. The single channel analyzer board, consisting of discrete logic components, operating in window modes, normal and integral. The pulse shaping block is made up of two voltage comparators working at 120 MHz with a response time > 60 ns and a logic anticoincidence system. The preamplifier promotes a noise reduction and introduces the impedance matching between the output of anode / diode photomultiplier tubes (PMTs) and subsequent equipment, providing an input impedance of 1MΩ and output impedance of 40 to 140Ω. The shaper amplifier is non-inverting and has variable input capacitance of 1000 pF. The upper and lower thresholds of the SCA are adjustable from 0 to ± 10V, and the equipment is compatible with various types of detectors, like PMTs coupled to sodium iodide crystals. For use with liquid scintillators and photodiodes with crystals (CsI: Tl) is proposed to include a preamplifier circuit pHEMT (pseudomorphic High Electron Mobility Transistor) integrated. Yet, the system presents the possibility of applications for various purposes of gamma spectroscopy and automatic detection of events producing of beta particles.

  18. A NIM (Nuclear Instrumentation Module) system conjugated with optional input for pHEMT amplifier for beta and gamma spectroscopy

    International Nuclear Information System (INIS)

    Konrad, Barbara; Lüdke, Everton

    2014-01-01

    This work presents a high speed NIM module (Nuclear Instrumentation Module) to detect radiation, gamma and muons, as part of a system for natural radiation monitoring and of extraterrestrial origin. The subsystem developed consists of a preamplifier and an integrated SCA (Single Channel Analyzer), including power supplies of ± 12 and ± 24V with derivations of +3.6 and ± 5V. The single channel analyzer board, consisting of discrete logic components, operating in window modes, normal and integral. The pulse shaping block is made up of two voltage comparators working at 120 MHz with a response time > 60 ns and a logic anticoincidence system. The preamplifier promotes a noise reduction and introduces the impedance matching between the output of anode / diode photomultiplier tubes (PMTs) and subsequent equipment, providing an input impedance of 1MΩ and output impedance of 40 to 140Ω. The shaper amplifier is non-inverting and has variable input capacitance of 1000 pF. The upper and lower thresholds of the SCA are adjustable from 0 to ± 10V, and the equipment is compatible with various types of detectors, like PMTs coupled to sodium iodide crystals. For use with liquid scintillators and photodiodes with crystals (CsI: Tl) is proposed to include a preamplifier circuit pHEMT (pseudomorphic High Electron Mobility Transistor) integrated. Yet, the system presents the possibility of applications for various purposes of gamma spectroscopy and automatic detection of events producing of beta particles

  19. Recessed insulator and barrier AlGaN/GaN HEMT: A novel structure for improving DC and RF characteristics

    Science.gov (United States)

    Razavi, S. M.; Zahiri, S. H.; Hosseini, S. E.

    2017-04-01

    In this study, a gallium nitride (GaN) high electron mobility transistor (HEMT) with recessed insulator and barrier is reported. In the proposed structure, insulator is recessed into the barrier at the drain side and barrier is recessed into the buffer layer at the source side. We study important device characteristics such as electric field, breakdown voltage, drain current, maximum output power density, gate-drain capacitance, short channel effects and DC transconductance using two-dimensional and two-carrier device simulator. Recessed insulator in the drain side of the proposed structure reduces maximum electric field in the channel and therefore increases the breakdown voltage and maximum output power density compared to the conventional counterpart. Also, gate-drain capacitance value in the proposed structure is less than that of the conventional structure. Overall, the proposed structure reduces short channel effects. Because of the recessed regions at both the source and the drain sides, the average barrier thickness of the proposed structure is not changed. Thus, the drain current of the proposed structure is almost equivalent to that of the conventional transistor. In this work, length ( L r) and thickness ( T r) of the recessed region of the barrier at the source side are the same as those of the insulator at the drain side.

  20. Interface traps at Al2O3/InAlN/GaN MOS-HEMT -on- 200 mm Si

    Science.gov (United States)

    Kumar, Sandeep; Remesh, Nayana; Dolmanan, S. B.; Tripathy, S.; Raghavan, S.; Muralidharan, R.; Nath, Digbijoy N.

    2017-11-01

    We report on the characterization of the interfaces of Al2O3/InAlN/GaN HEMT structure grown on 200 mm diameter silicon using conductance dispersion technique. Irreversible threshold voltage (VTH) shift of up to +∼2.5 V was observed due to the gate stress induced activation of acceptor states. Further, frequency dependent VTH shift during capacitance voltage measurements were also recorded due to the presence of slow traps at InAlN/GaN interface. The conductance dispersion indicated the presence of acceptor traps of the order of ∼4 × 1012 to 7 × 1013 cm-2 eV-1 with a time constant of ∼10 to 350 μs at the InAlN/GaN interface. Trap density at the Al2O3/InAlN was found to be in similar range but with a time constant of ∼2 μs. The presence of high density of traps at InAlN/GaN interface is attributed to the unavoidable growth interruption before the start of InAlN growth.

  1. Improvements to the extraction of an AlGaN/GaN HEMT small-signal model

    Energy Technology Data Exchange (ETDEWEB)

    Pu Yan; Pang Lei; Wang Liang; Chen Xiaojuan; Li Chengzhan; Liu Xinyu, E-mail: puyan_66721@hotmail.co [Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China)

    2009-12-15

    The accurate extraction of AlGaN/GaN HEMT small-signal models, which is an important step in large-signal modeling, can exactly reflect the microwave performance of the physical structure of the device. A new method of extracting the parasitic elements is presented, and an open dummy structure is introduced to obtain the parasitic capacitances. With a Schottky resistor in the gate, a new method is developed to extract R{sub g}. In order to characterize the changes of the depletion region under various drain voltages, the drain delay factor is involved in the output conductance of the device. Compared to the traditional method, the fitting of S {sub 11} and S {sub 22} is improved, and f{sub T} and f{sub max} can be better predicted. The validity of the proposed method is verified with excellent correlation between the measured and simulated S-parameters in the range of 0.1 to 26.1 GHz. (semiconductor devices)

  2. Channel Temperature Determination for AlGaN/GaN HEMTs on SiC and Sapphire

    Science.gov (United States)

    Freeman, Jon C.; Mueller, Wolfgang

    2008-01-01

    Numerical simulation results (with emphasis on channel temperature) for a single gate AlGaN/GaN High Electron Mobility Transistor (HEMT) with either a sapphire or SiC substrate are presented. The static I-V characteristics, with concomitant channel temperatures (T(sub ch)) are calculated using the software package ATLAS, from Silvaco, Inc. An in-depth study of analytical (and previous numerical) methods for the determination of T(sub ch) in both single and multiple gate devices is also included. We develop a method for calculating T(sub ch) for the single gate device with the temperature dependence of the thermal conductivity of all material layers included. We also present a new method for determining the temperature on each gate in a multi-gate array. These models are compared with experimental results, and show good agreement. We demonstrate that one may obtain the channel temperature within an accuracy of +/-10 C in some cases. Comparisons between different approaches are given to show the limits, sensitivities, and needed approximations, for reasonable agreement with measurements.

  3. Urinary Biomarkers KIM-1 and NGAL for Detection of Chronic Kidney Disease of Uncertain Etiology (CKDu) among Agricultural Communities in Sri Lanka

    Science.gov (United States)

    Mohammed Abdul, Khaja Shameem; Eakanayake, Eakanayake M. D. V.; Jayasinghe, Sudheera Sammanthi; Jayasumana, Channa; Asanthi, Hewa Bandulage; Perera, Hettiarachigae S. D.; Chaminda, Gamage G. Tushara; Chandana, Ediriweera P. S.; Siribaddana, Sisira H.

    2016-01-01

    Chronic Kidney Disease of uncertain etiology (CKDu) is an emerging epidemic among farming communities in rural Sri Lanka. Victims do not exhibit common causative factors, however, histopathological studies revealed that CKDu is a tubulointerstitial disease. Urine albumin or albumin-creatinine ratio is still being used as a traditional diagnostic tool to identify CKDu, but accuracy and prevalence data generated are questionable. Urinary biomarkers have been used in similar nephropathy and are widely recognised for their sensitivity, specificity and accuracy in determining CKDu and early renal injury. However, these biomarkers have never been used in diagnosing CKDu in Sri Lanka. Male farmers (n = 1734) were recruited from 4 regions in Sri Lanka i.e. Matara and Nuwara Eliya (farming locations with no CKDu prevalence) and two CKDu emerging locations from Hambantota District in Southern Sri Lanka; Angunakolapelessa (EL1) and Bandagiriya (EL2). Albuminuria (ACR ≥ 30mg/g); serum creatinine based estimation of glomerular filtration rate (eGFR); creatinine normalized urinary kidney injury molecule (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were measured. Fourteen new CKDu cases (18%) from EL1 and nine CKDu cases (9%) from EL2 were recognized for the first time from EL1, EL2 locations, which were previously considered as non-endemic of the disease and associated with persistent albuminuria (ACR ≥ 30mg/g Cr). No CKDu cases were identified in non-endemic study locations in Matara (CM) and Nuwara Eliya (CN). Analysis of urinary biomarkers showed urinary KIM-1 and NGAL were significantly higher in new CKDu cases in EL1 and EL2. However, we also reported significantly higher KIM-1 and NGAL in apparently healthy farmers in EL 1 and EL 2 with comparison to both control groups. These observations may indicate possible early renal damage in absence of persistent albuminuria and potential capabilities of urinary KIM-1 and NGAL in early detection of renal injury

  4. Letter to the Editor on the article “Indirect land use change for biofuels: Testing predictions and improving analytical methodologies” by S. Kim and B. Dale

    OpenAIRE

    O'HARE Michael; DE LUCCHI Mark; EDWARDS Robert; FRITSCHE Uwe; GIBBS Holly; HERTEL Thomas; HILL Jason; KAMMEN Daniel; MARELLI Luisa; MULLIGAN DECLAN; PLEVIN Richard; TYNER Wallace

    2011-01-01

    The article, “Indirect land use change for biofuels: Testing predictions and improving analytical methodologies” by S. Kim and B. Dale, presents a principal inference not supported by its results, rests on a fundamental conceptual error, and has no place in the current discussion of biofuels’ climate effects. As it is already receiving press attention as though its findings are considerable, it requires a detailed refutation. Briefly, the most important errors in the paper are • taking co...

  5. Can You Anchor a Shimmering Nation State via Regional Indigenous Roots? Kim Scott talks to Anne Brewster about That Deadman Dance

    Directory of Open Access Journals (Sweden)

    Anne Brewster

    2011-10-01

    Full Text Available This interview focuses mainly on Kim Scott’s new novel That Deadman Dance which won the regional Commonwealth Writers Prize (Southeast Asian and Pacific region and the Miles Franklin Award. The topics of conversation include Scott’s involvement in the Noongar language project (and the relationship of this project to the novel, the novel itself, the challenges of writing in English, the resistance paradigm and indigenous sovereignty and nationalism.

  6. KIMS, CEDIA, and HS-CEDIA immunoassays are inadequately sensitive for detection of benzodiazepines in urine from patients treated for chronic pain.

    Science.gov (United States)

    Darragh, Alicia; Snyder, Marion L; Ptolemy, Adam S; Melanson, Stacy

    2014-01-01

    Patients treated for chronic pain may frequently undergo urine drug testing to monitor medication compliance and detect undisclosed prescribed or illicit drug use. Due to the increasing use and abuse of benzodiazepines, this class of medications is often included in drug screening panels. However, immunoassay-based methods lack the requisite sensitivity for detecting benzodiazepine use in this population primarily due to their poor cross-reactivity with several major urinary benzodiazepine metabolites. A High Sensitivity Cloned Enzyme Donor Immunoassay (HS-CEDIA), in which beta-glucuronidase is added to the reagent, has been shown to perform better than traditional assays, but its performance in patients treated for chronic pain is not well characterized. To determine the diagnostic accuracy of HS-CEDIA, as compared to the Cloned Enzyme Donor Immunoassay (CEDIA) and Kinetic Interaction of Microparticles in Solution (KIMS) screening immunoassays and liquid chromatography-tandem mass spectrometry (LC-MS/MS), for monitoring benzodiazepine use in patients treated for chronic pain. A study of the diagnostic accuracy of urine benzodiazepine immunoassays. The study was conducted at an academic tertiary care hospital with a clinical laboratory that performs urine drug testing for monitoring medication compliance in pain management. A total of 299 urine specimens from patients treated for chronic pain were screened for the presence of benzodiazepines using the HS-CEDIA, CEDIA, and KIMS assays. The sensitivity and specificity of the screening assays were determined using the LC-MS/MS results as the reference method. Of the 299 urine specimens tested, 141 (47%) confirmed positive for one or more of the benzodiazepines/metabolites by LC-MS/MS. All 3 screens were 100% specific with no false-positive results. The CEDIA and KIMS sensitivities were 55% (78/141) and 47% (66/141), respectively. Despite the relatively higher sensitivity of the HS-CEDIA screening assay (78%; 110

  7. Electrical and Optical Characterization of AlGaN/GaN HEMTs with In Situ and Ex Situ Deposited SiN x Layers

    Science.gov (United States)

    Tadjer, Marko J.; Anderson, Travis J.; Hobart, Karl D.; Mastro, Michael A.; Hite, Jennifer K.; Caldwell, Joshua D.; Picard, Yoosuf N.; Kub, Fritz J.; Eddy, Charles R.

    2010-11-01

    A comparative study of AlGaN/GaN high-electron-mobility transistor (HEMT) surface passivation using ex situ and in situ deposited SiN x is presented. Performing ex situ SiN x passivation increased the reverse gate leakage and off-state channel leakage by about three orders of magnitude. The in situ SiN x layer was characterized using transmission electron microscopy (TEM) and capacitance-voltage (CV) measurements. Photoluminescence (PL) spectra indicated a reduction of nonradiative recombination centers in in situ SiN x -passivated samples, indicating improved crystal quality. CV measurements indicated a reduction of surface state density as well, and thus better overall passivation using in situ SiN x . Electroluminescence (EL) images of the channel regions in AlGaN/GaN HEMT devices operating in forward blocking mode with up to 400 V drain bias demonstrated reduced channel emission profiles of in situ-passivated devices. Compared with a nonpassivated reference sample, the reduced EL emission profiles correlated with a reduced channel temperature on ex situ SiN x -passivated devices.

  8. The effect of ammonia flow in the AlN spacer on the electrical properties of InAlN/AlN/GaN HEMT structures

    International Nuclear Information System (INIS)

    Gamarra, Piero; Lacam, Cedric; Magis, Michelle; Tordjman, Maurice; Di Forte Poisson, Marie-Antoinette

    2012-01-01

    During the past few years it has been reported that a thin AlN spacer of few nanometers needs to be inserted in InAlN/GaN high electron mobility transistors (HEMTs) to obtain high 2DEG carrier mobility. This work presents a systematic study of the effects of varying the ammonia flow in the AlN spacer of InAlN/AlN/GaN HEMTs grown by low pressure metalorganic vapour phase epitaxy (LP-MOVPE). The strain state, the surface roughness and the growth rate of AlN were found to be dependent on the V/III ratio. In addition the ammonia flow in the interlayer has a strong impact on the structural properties of the subsequent InAlN barrier layer and on the electrical properties of the structure. A sheet resistance as low as 327 Ω/□ with a sheet carrier density of 1.5 x 10 13 cm -2 has been obtained at room temperature. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. The effect of ammonia flow in the AlN spacer on the electrical properties of InAlN/AlN/GaN HEMT structures

    Energy Technology Data Exchange (ETDEWEB)

    Gamarra, Piero; Lacam, Cedric; Magis, Michelle; Tordjman, Maurice; Di Forte Poisson, Marie-Antoinette [III-V Lab., Marcussis (France)

    2012-01-15

    During the past few years it has been reported that a thin AlN spacer of few nanometers needs to be inserted in InAlN/GaN high electron mobility transistors (HEMTs) to obtain high 2DEG carrier mobility. This work presents a systematic study of the effects of varying the ammonia flow in the AlN spacer of InAlN/AlN/GaN HEMTs grown by low pressure metalorganic vapour phase epitaxy (LP-MOVPE). The strain state, the surface roughness and the growth rate of AlN were found to be dependent on the V/III ratio. In addition the ammonia flow in the interlayer has a strong impact on the structural properties of the subsequent InAlN barrier layer and on the electrical properties of the structure.istance as low as 327 {omega}/{open_square} with a sheet carrier density of 1.5 x 10{sup 13} cm{sup -2} has been obtained at room temperature. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Design and simulation of a novel 1400 V–4000 V enhancement mode buried gate GaN HEMT for power applications

    International Nuclear Information System (INIS)

    Faramehr, Soroush; Kalna, Karol; Igić, Petar

    2014-01-01

    A novel enhancement mode structure, a buried gate gallium nitride (GaN) high electron mobility transistor (HEMT) with a breakdown voltage (BV) of 1400 V–4000 V for a source-to-drain spacing (L SD ) of 6 μm–32 μm, is investigated using simulations by Silvaco Atlas. The simulations are based on meticulous calibration of a conventional lateral 1 μm gate length GaN HEMT with a source-to-drain spacing of 6 μm against its experimental transfer characteristics and BV. The specific on-resistance R S for the new power transistor with the source-to-drain spacing of 6 μm showing BV = 1400 V and the source-to-drain spacing of 8 μm showing BV = 1800 V is found to be 2.3 mΩ · cm 2 and 3.5 mΩ · cm 2 , respectively. Further improvement up to BV  = 4000 V can be achieved by increasing the source-to-drain spacing to 32 μm with the specific on-resistance of R S = 35.5 mΩ · cm 2 . The leakage current in the proposed devices stays in the range of ∼5 × 10 −9 mA mm −1 . (paper)

  11. Design and analysis of 30 nm T-gate InAlN/GaN HEMT with AlGaN back-barrier for high power microwave applications

    Science.gov (United States)

    Murugapandiyan, P.; Ravimaran, S.; William, J.; Meenakshi Sundaram, K.

    2017-11-01

    In this article, we present the DC and microwave characteristics of a novel 30 nm T-gate InAlN/AlN/GaN HEMT with AlGaN back-barrier. The device structure is simulated by using Synopsys Sentaurus TCAD Drift-Diffusion transport model at room temperature. The device features are heavily doped (n++ GaN) source/drain regions with Si3N4 passivated device surface for reducing the contact resistances and gate capacitances of the device, which uplift the microwave characteristics of the HEMTs. 30 nm gate length D-mode (E-mode) HEMT exhibited a peak drain current density Idmax of 2.3 (2.42) A/mm, transconductance gm of 1.24(1.65) S/mm, current gain cut-off frequency ft of 262 (246) GHz, power gain cut-off frequency fmax of 246(290) GHz and the three terminal off-state breakdown voltage VBR of 40(38) V. The preeminent microwave characteristics with the higher breakdown voltage of the proposed GaN-based HEMT are the expected to be the most optimistic applicant for future high power millimeter wave applications.

  12. Urinary Biomarkers KIM-1 and NGAL for Detection of Chronic Kidney Disease of Uncertain Etiology (CKDu among Agricultural Communities in Sri Lanka.

    Directory of Open Access Journals (Sweden)

    Pallagae Mangala C S De Silva

    2016-09-01

    Full Text Available Chronic Kidney Disease of uncertain etiology (CKDu is an emerging epidemic among farming communities in rural Sri Lanka. Victims do not exhibit common causative factors, however, histopathological studies revealed that CKDu is a tubulointerstitial disease. Urine albumin or albumin-creatinine ratio is still being used as a traditional diagnostic tool to identify CKDu, but accuracy and prevalence data generated are questionable. Urinary biomarkers have been used in similar nephropathy and are widely recognised for their sensitivity, specificity and accuracy in determining CKDu and early renal injury. However, these biomarkers have never been used in diagnosing CKDu in Sri Lanka. Male farmers (n = 1734 were recruited from 4 regions in Sri Lanka i.e. Matara and Nuwara Eliya (farming locations with no CKDu prevalence and two CKDu emerging locations from Hambantota District in Southern Sri Lanka; Angunakolapelessa (EL1 and Bandagiriya (EL2. Albuminuria (ACR ≥ 30mg/g; serum creatinine based estimation of glomerular filtration rate (eGFR; creatinine normalized urinary kidney injury molecule (KIM-1 and neutrophil gelatinase-associated lipocalin (NGAL were measured. Fourteen new CKDu cases (18% from EL1 and nine CKDu cases (9% from EL2 were recognized for the first time from EL1, EL2 locations, which were previously considered as non-endemic of the disease and associated with persistent albuminuria (ACR ≥ 30mg/g Cr. No CKDu cases were identified in non-endemic study locations in Matara (CM and Nuwara Eliya (CN. Analysis of urinary biomarkers showed urinary KIM-1 and NGAL were significantly higher in new CKDu cases in EL1 and EL2. However, we also reported significantly higher KIM-1 and NGAL in apparently healthy farmers in EL 1 and EL 2 with comparison to both control groups. These observations may indicate possible early renal damage in absence of persistent albuminuria and potential capabilities of urinary KIM-1 and NGAL in early detection of renal

  13. Suvremene muško-ženske konstrukcije u američkim televizijskim serijama Seks i grad, Kućanice i Vatreni dečki

    OpenAIRE

    Kosanović, Silvana

    2008-01-01

    Prva istraživanja o reprezentaciji roda u popularnoj kulturi počela su s feminističkim proučavanjem konstrukcije ženskosti, dok se muškost prihvaćala kao nešto što se implicite podrazumijeva kao normativ pa se uglavnom zasebno nije ni proučavala. S promjenama u društvenim i ekonomskim uvjetima, jačim prodorom feminističke teorije, britanskih kulturnih studija, američkih televizijskih studija, postfeminističke kritike i s jačanjem queer teorije, pitanje medijske reprezentacije roda, osobito mu...

  14. Effects of NH3 Flow Rate During AlGaN Barrier Layer Growth on the Material Properties of AlGaN/GaN HEMT Heterostructure

    Science.gov (United States)

    Lumbantoruan, Franky J.; Wong, Yuen-Yee; Huang, Wei-Ching; Yu, Hung-Wei; Chang, Edward-Yi

    2017-10-01

    NH3 flow rate during AlGaN barrier layer growth not only affects the growth efficiency and surface morphology as a result of parasitic reactions but also influences the concentration of carbon impurity in the AlGaN barrier. Carbon, which decomposes from metal precursors, plays a role in electron compensation for AlGaN/GaN HEMT. No 2-dimensional electron gas (2-DEG) was detected in the AlGaN/GaN structure if grown with 0.5 slm of NH3 due to the presence of higher carbon impurity (2.6 × 1019 cm-2). When the NH3 flow rate increased to 6.0 slm, the carbon impurity reduced to 2.10 × 1018 atom cm-3 and the 2 DEG electron density recovered to 9.57 × 1012 cm-2.

  15. Normally-off AlGaN/GaN-based MOS-HEMT with self-terminating TMAH wet recess etching

    Science.gov (United States)

    Son, Dong-Hyeok; Jo, Young-Woo; Won, Chul-Ho; Lee, Jun-Hyeok; Seo, Jae Hwa; Lee, Sang-Heung; Lim, Jong-Won; Kim, Ji Heon; Kang, In Man; Cristoloveanu, Sorin; Lee, Jung-Hee

    2018-03-01

    Normally-off AlGaN/GaN-based MOS-HEMT has been fabricated by utilizing damage-free self-terminating tetramethyl ammonium hydroxide (TMAH) recess etching. The device exhibited a threshold voltage of +2.0 V with good uniformity, extremely small hysteresis of ∼20 mV, and maximum drain current of 210 mA/mm. The device also exhibited excellent off-state performances, such as breakdown voltage of ∼800 V with off-state leakage current as low as ∼10-12 A and high on/off current ratio (Ion/Ioff) of 1010. These excellent device performances are believed to be due to the high quality recessed surface, provided by the simple self-terminating TMAH etching.

  16. Modeling and simulation of enhancement mode p-GaN Gate AlGaN/GaN HEMT for RF circuit switch applications

    Science.gov (United States)

    Panda, D. K.; Lenka, T. R.

    2017-06-01

    An enhancement mode p-GaN gate AlGaN/GaN HEMT is proposed and a physics based virtual source charge model with Landauer approach for electron transport has been developed using Verilog-A and simulated using Cadence Spectre, in order to predict device characteristics such as threshold voltage, drain current and gate capacitance. The drain current model incorporates important physical effects such as velocity saturation, short channel effects like DIBL (drain induced barrier lowering), channel length modulation (CLM), and mobility degradation due to self-heating. The predicted I d-V ds, I d-V gs, and C-V characteristics show an excellent agreement with the experimental data for both drain current and capacitance which validate the model. The developed model was then utilized to design and simulate a single-pole single-throw (SPST) RF switch.

  17. Theoretical and experimental studies of the current–voltage and capacitance–voltage of HEMT structures and field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Tarasova, E. A.; Obolenskaya, E. S., E-mail: obolensk@rf.unn.ru; Hananova, A. V.; Obolensky, S. V. [Lobachevsky State University of Nizhny Novgorod (NNSU) (Russian Federation); Zemliakov, V. E.; Egorkin, V. I. [National Research University of Electronic Technology (MIET) (Russian Federation); Nezhenzev, A. V. [Lobachevsky State University of Nizhny Novgorod (NNSU) (Russian Federation); Saharov, A. V.; Zazul’nokov, A. F.; Lundin, V. V.; Zavarin, E. E. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Medvedev, G. V. [JSC RPE Salut (Russian Federation)

    2016-12-15

    The sensitivity of classical n{sup +}/n{sup –} GaAs and AlGaN/GaN structures with a 2D electron gas (HEMT) and field-effect transistors based on these structures to γ-neutron exposure is studied. The levels of their radiation hardness were determined. A method for experimental study of the structures on the basis of a differential analysis of their current–voltage characteristics is developed. This method makes it possible to determine the structure of the layers in which radiation-induced defects accumulate. A procedure taking into account changes in the plate area of the experimentally measured barrier-contact capacitance associated with the emergence of clusters of radiation-induced defects that form dielectric inclusions in the 2D-electron-gas layer is presented for the first time.

  18. Theoretical and experimental studies of the current–voltage and capacitance–voltage of HEMT structures and field-effect transistors

    International Nuclear Information System (INIS)

    Tarasova, E. A.; Obolenskaya, E. S.; Hananova, A. V.; Obolensky, S. V.; Zemliakov, V. E.; Egorkin, V. I.; Nezhenzev, A. V.; Saharov, A. V.; Zazul’nokov, A. F.; Lundin, V. V.; Zavarin, E. E.; Medvedev, G. V.

    2016-01-01

    The sensitivity of classical n + /n – GaAs and AlGaN/GaN structures with a 2D electron gas (HEMT) and field-effect transistors based on these structures to γ-neutron exposure is studied. The levels of their radiation hardness were determined. A method for experimental study of the structures on the basis of a differential analysis of their current–voltage characteristics is developed. This method makes it possible to determine the structure of the layers in which radiation-induced defects accumulate. A procedure taking into account changes in the plate area of the experimentally measured barrier-contact capacitance associated with the emergence of clusters of radiation-induced defects that form dielectric inclusions in the 2D-electron-gas layer is presented for the first time.

  19. Role of AlGaN/GaN interface traps on negative threshold voltage shift in AlGaN/GaN HEMT

    Science.gov (United States)

    Malik, Amit; Sharma, Chandan; Laishram, Robert; Bag, Rajesh Kumar; Rawal, Dipendra Singh; Vinayak, Seema; Sharma, Rajesh Kumar

    2018-04-01

    This article reports negative shift in the threshold-voltage in AlGaN/GaN high electron mobility transistor (HEMT) with application of reverse gate bias stress. The device is biased in strong pinch-off and low drain to source voltage condition for a fixed time duration (reverse gate bias stress), followed by measurement of transfer characteristics. Negative threshold voltage shift after application of reverse gate bias stress indicates the presence of more carriers in channel as compared to the unstressed condition. We propose the presence of AlGaN/GaN interface states to be the reason of negative threshold voltage shift, and developed a process to electrically characterize AlGaN/GaN interface states. We verified the results with Technology Computer Aided Design (TCAD) ATLAS simulation and got a good match with experimental measurements.

  20. High performance AlInN/AlN/GaN p-GaN back barrier Gate-Recessed Enhancement-Mode HEMT

    Science.gov (United States)

    Adak, Sarosij; Sarkar, Arghyadeep; Swain, Sanjit; Pardeshi, Hemant; Pati, Sudhansu Kumar; Sarkar, Chandan Kumar

    2014-11-01

    In the present work, we propose and perform extensive simulation study of the novel device structure having a p-GaN back barrier layer inserted in the conventional AlInN/AlN/GaN Gate-Recessed Enhancement-Mode HEMT device for reducing the short channel effects, gate leakage and enhancing the frequency performance. The influence of the p-GaN back barrier layer on the device performance of the newly proposed structure is done using 2D Sentaurus TCAD simulations. The simulations use Drift-Diffusion (DD) model, Masetti and Canali model, which are calibrated/validated with the previously published experimental results. Simulation are done to analyze the transfer characteristics, transconductance (gm), Gate leakage current (Ig), drain induced barrier lowering (DIBL), subthreshold slope (SS), threshold voltage (Vth), On-current Off-current ratio (Ion/Ioff), gate capacitance (Cgg) and cut off frequency (fT) of the proposed device. A comparison is done between the device without back barrier layer and the proposed device with p-GaN back barrier layer. Use of p-GaN back barrier layer helps to achieve a higher positive Vth due to the depletion effect, reduced Ig, reduced DIBL, prevents degradation of SS and helps to increase the fT. Very impressive fT up to 123 GHz, as compared to 70 GHz for the device without back barrier. These results indicate that AlInN/AlN/GaN Gate-Recessed Enhancement-Mode HEMT structure with p-GaN back barrier is a promising candidate for microwave and switching application.

  1. Comparison of shallow-mesa InAs/AlSb HEMTs with and without early-protection for long-term stability against Al(Ga)Sb oxidation*

    International Nuclear Information System (INIS)

    Lefebvre, Eric; Moschetti, Giuseppe; Malmkvist, Mikael; Grahn, Jan; Desplanque, Ludovic; Wallart, Xavier

    2014-01-01

    The fabrication process of InAs/AlSb high electron mobility transistors (HEMTs) has been improved by depositing, after the shallow-mesa isolation of the active area, a thin SiN x -film on the exposed AlGaSb mesa floor. Devices with and without this early-protection against Al(Ga)Sb oxidation have been fabricated simultaneously on the same chip for fair comparison. Optical observations and electrical measurements over four and half years demonstrated the physical stability provided by this extra-coverage. The electrical measurements also revealed that the induced deposition of the probing pads and of the extrinsic part of the gates on SiN x slightly reduced the maximum drain current I D  (−9%) and the transconductance g m (−12%) to, respectively, 700 mA mm −1  and 1220 mS mm −1  for 2 × 20 µm 2  InAs/AlSb HEMTs with a 140 nm recessed gate. On the other hand, the gate-leakage current I G  was lowered by more than one order of magnitude, leading to a better pinch-off behavior and increased values of cut-off frequency f T (+4%) and maximum frequency of oscillation f max  (+36%) to, respectively, 230 GHz and 190 GHz at a drain voltage V DS  of 0.5 V. (paper)

  2. „Ritualno” i „struktuirano” odbacivanje u arheološkim interpretacijama: primer sistema za vodosnabdevanje na lokalitetu „Kale” u Krševici

    Directory of Open Access Journals (Sweden)

    Ivan Vranić

    2016-11-01

    Full Text Available Pitanja vezana za rituale, kultove, religiju ili magiju predstavljaju važne ali u značajnoj meri zanemarene i teorijski nedovoljno precizno utemeljene teme u savremenim arheološkim interpretacijama. Cilj rada jeste da na konkretnim primerima potencijalno ritualnih aktivnosti vezanih za izgradnju i moguće „ritualno ubijanje” sistema za vodosnabdevanje na lokalitetu „Kale” u Krševici pokaže kako ovo zanemarivanje nije samo posledica aktuelnosti i trendova o odabiru istraživačkih tema, već se radi o ozbiljnijem problemu koji pokazuje određene nedostatke savremenih pristupa vezanih za arheologiju identiteta i koncepte struktuiranog ili simboličkog odbacivanja.

  3. The prevalence of musculoskeletal disorders and occupational risk factors in Kashan SAIPA automobile industry workers by key indicator method (KIM, 1390

    Directory of Open Access Journals (Sweden)

    2012-05-01

    Full Text Available Introduction: work related musculoskeletal disorders are the most wide spread type of occupational diseases among workers. Awkward body postures during work and manual material handling are among the most important risk factors of musculoskeletal disorders in different jobs. Due to importance of recognizing these factors prevalence and risk factor of work related musculoskeletal disorders, this research was aimed to study the among employees of Kashan City’s Saipa automobile industry in 2011. .Material and Method: This study is a descriptive-cross sectional study conducted among workers with manual material handling 37 activities and 84 work duties. To recognize musculoskeletal disorders, body map questionnaire was applied and occupational risk factors were evaluated using Key Index Method (KIM. Data was analyzed using SPSS and Excel software. .Result: Highest prevalence of musculoskeletal disorders was in low and upper back region (%92. Based on the results from KIM, workers in the installing the tire, shuttle-aided fitting of seat, and engine work station had higher risk level with the scores of 66, 52 and 52, respectively. Risk level among three individuals (%3.6 was at 1, 40 (%47.6 at 2, 38 (%45.2 risk level 3, and 3 (%3.6 at 4. .Conclusion: Awkward body posture, improper twisting and flexion of low back were major risk factor among worker doing manual material handling tasks. Regarding the high prevalence of musculoskeletal disorders, appropriate ergonomic interventions such as engineering and organization interactions can reduce this risk factors (posture, heavy load, duration, workplace conditions as much as the risk level reach to an acceptable level.

  4. Scattering and mobility in indium gallium arsenide channel, pseudomorphic high electron mobility transistors (InGaAs pHEMTs)

    International Nuclear Information System (INIS)

    Pearson, J.L.

    1999-03-01

    Extensive transport measurements have been completed on deep and shallow-channelled InGaAs p-HEMTs of varying growth temperature, indium content, spacer thickness and doping density, with a view to a thorough characterisation, both in the metallic and the localised regimes. Particular emphasis was given to MBE grown layers, with characteristics applicable for device use, but low measurement temperatures were necessary to resolve the elastic scattering mechanisms. Measurements made in the metallic regime included transport and quantum mobility - the former over a range of temperatures between 1.5K to 300K. Conductivity measurements were also acquired in the strong localisation regime between about 1.5K and 100K. Experimentally determined parameters were tested for comparison with those predicted by an electrostatic model. Excellent agreement was obtained for carrier density. Other parameters were less well predicted, but the relevant experimental measurements, including linear depletion of the 2DEG, were sensitive to any excess doping above a 'critical' value determined by the model. At low temperature (1.5K), it was found that in all samples tested, transport mobility was strongly limited at all carrier densities by a large q mechanism, possibly intrinsic to the channel. This was ascribed either to scattering by the long-range potentials arising from the indium concentration fluctuations or fluctuations in the thickness of the channel layer. This mechanism dominates the transport at low carrier densities for all samples, but at high carrier density, an additional mechanism is significant for samples with the thinnest spacers tested (2.5nm). This is ascribed to direct electron interaction with the states of the donor layer, and produces a characteristic transport mobility peak. At higher carrier densities, past the peak, quantum mobility was found only to increase monotonically in value. Remote ionised impurity scattering while significant, particularly for samples

  5. "The Day All of the Different Parts of Me Can Come Along": Intersectionality and U.S. Third World Feminism in the Poetry of Pat Parker and Willyce Kim.

    Science.gov (United States)

    Van Ausdall, Mimi Iimuro

    2015-01-01

    This article brings to light the poetry of Pat Parker and Willyce Kim, two key figures within the 1970s and '80s women in print movement. While Parker and Kim have been rightly placed within African-American and Asian-American histories, respectively, and working-class and lesbian-feminist literary histories, their work is most fully understood within the context of U.S. Third World Feminism. Through close readings of poetic form and content in addition to engagement with current debates about intersectionality as a methodology, the article links Kim and Parker's works to central contributions of U.S. Third World Feminism such as intersectionality and power across and within difference that continue to influence feminist theory today.

  6. Improved DC and RF performance of InAlAs/InGaAs InP based HEMTs using ultra-thin 15 nm ALD-Al2O3 surface passivation

    Science.gov (United States)

    Asif, Muhammad; Chen, Chen; Peng, Ding; Xi, Wang; Zhi, Jin

    2018-04-01

    Owing to the great influence of surface passivation on DC and RF performance of InP-based HEMTs, the DC and RF performance of InAlAs/InGaAs InP HEMTs were studied before and after passivation, using an ultra-thin 15 nm atomic layer deposition Al2O3 layer. Increase in Cgs and Cgd was significantly limited by scaling the thickness of the Al2O3 layer. For verification, an analytical small-signal equivalent circuit model was developed. A significant increase in maximum transconductance (gm) up to 1150 mS/mm, drain current (IDS) up to 820 mA/mm and fmax up to 369.7 GHz was observed, after passivation. Good agreement was obtained between the measured and the simulated results. This shows that the RF performance of InP-based HEMTs can be improved by using an ultra-thin ALD-Al2O3 surface passivation.

  7. Design and simulation of a novel E-mode GaN MIS-HEMT based on a cascode connection for suppression of electric field under gate and improvement of reliability

    Science.gov (United States)

    Li, Weiyi; Zhang, Zhili; Fu, Kai; Yu, Guohao; Zhang, Xiaodong; Sun, Shichuang; Song, Liang; Hao, Ronghui; Fan, Yaming; Cai, Yong; Zhang, Baoshun

    2017-07-01

    We proposed a novel AlGaN/GaN enhancement-mode (E-mode) high electron mobility transistor (HEMT) with a dual-gate structure and carried out the detailed numerical simulation of device operation using Silvaco Atlas. The dual-gate device is based on a cascode connection of an E-mode and a D-mode gate. The simulation results show that electric field under the gate is decreased by more than 70% compared to that of the conventional E-mode MIS-HEMTs (from 2.83 MV/cm decreased to 0.83 MV/cm). Thus, with the discussion of ionized trap density, the proposed dual-gate structure can highly improve electric field-related reliability, such as, threshold voltage stability. In addition, compared with HEMT with field plate structure, the proposed structure exhibits a simplified fabrication process and a more effective suppression of high electric field. Project supported by the Key Technologies Support Program of Jiangsu Province (No. BE2013002-2) and the National Key Scientific Instrument and Equipment Development Projects of China (No. 2013YQ470767).

  8. Static and dynamic characteristics of Lg 50 nm InAlN/AlN/GaN HEMT with AlGaN back-barrier for high power millimeter wave applications

    Directory of Open Access Journals (Sweden)

    P. Murugapandiyan

    2017-12-01

    Full Text Available A novel 50 nm recessed T-gate AlN spacer based InAlN/GaN HEMT with AlGaN back-barrier is designed. The static and dynamic characteristics of the proposed device structure are investigated using Synopsys TCAD tool. The remarkable potential device features such as heavily doped source/drain region, Al2O3 passivated device surface helped the device to suppress the parasitic resistances and capacitances of the transistor for enhancing the microwave characteristics. The designed InAlN/GaN HEMT exhibits the sheet carrier density (ns of 1.9 × 1013 cm−2, the drain current density (Ids of 2.1 A/mm, the transconductance (gm of 800 mS/mm, the breakdown voltage (VBR of 40 V, the current gain cut-off frequency (ft of 221 GHz and the power gain cut-off frequency (fmax of 290 GHz. The superior static and dynamic characteristics of obtained InAlN/GaN HEMTs undoubtedly placed the device at the forefront for high power millimeter wave applications.

  9. Urinary Vitamin D Binding Protein and KIM-1 Are Potent New Biomarkers of Major Adverse Renal Events in Patients Undergoing Coronary Angiography.

    Directory of Open Access Journals (Sweden)

    Lyubov Chaykovska

    Full Text Available Vitamin-D-binding protein (VDBP is a low molecular weight protein that is filtered through the glomerulus as a 25-(OH vitamin D 3/VDBP complex. In the normal kidney VDBP is reabsorbed and catabolized by proximal tubule epithelial cells reducing the urinary excretion to trace amounts. Acute tubular injury is expected to result in urinary VDBP loss. The purpose of our study was to explore the potential role of urinary VDBP as a biomarker of an acute renal damage.We included 314 patients with diabetes mellitus or mild renal impairment undergoing coronary angiography and collected blood and urine before and 24 hours after the CM application. Patients were followed for 90 days for the composite endpoint major adverse renal events (MARE: need for dialysis, doubling of serum creatinine after 90 days, unplanned emergency rehospitalization or death.Increased urine VDBP concentration 24 hours after contrast media exposure was predictive for dialysis need (no dialysis: 113.06 ± 299.61 ng/ml, n = 303; need for dialysis: 613.07 ± 700.45 ng/ml, n = 11, Mean ± SD, p<0.001, death (no death during follow-up: 121.41 ± 324.45 ng/ml, n = 306; death during follow-up: 522.01 ± 521.86 ng/ml, n = 8; Mean ± SD, p<0.003 and MARE (no MARE: 112.08 ± 302.00 ng/ml, n = 298; MARE: 506.16 ± 624.61 ng/ml, n = 16, Mean ± SD, p<0.001 during the follow-up of 90 days after contrast media exposure. Correction of urine VDBP concentrations for creatinine excretion confirmed its predictive value and was consistent with increased levels of urinary Kidney Injury Molecule-1 (KIM-1 and baseline plasma creatinine in patients with above mentioned complications. The impact of urinary VDBP and KIM-1 on MARE was independent of known CIN risk factors such as anemia, preexisting renal failure, preexisting heart failure, and diabetes.Urinary VDBP is a promising novel biomarker of major contrast induced nephropathy-associated events 90 days after contrast media exposure.

  10. Analysis of the coexisting pathways for NO and N2O formation in Chernozem using the (15)N-tracer SimKIM-Advanced model.

    Science.gov (United States)

    Stange, Claus Florian; Spott, Oliver; Russow, Rolf

    2013-01-01

    The nitrogen (N) cycle consists of a variety of microbial processes. These processes often occur simultaneously in soils, but respond differently to local environmental conditions due to process-specific biochemical restrictions (e.g. oxygen levels). Hence, soil nitrogen cycling (e.g. soil N gas production through nitrification and denitrification) is individually affected through these processes, resulting in the complex and highly dynamic behaviour of total soil N turnover. The development and application of methods that facilitate the quantification of individual contributions of coexisting processes is a fundamental prerequisite for (i) understanding the dynamics of soil N turnover and (ii) implementing these processes in ecosystem models. To explain the unexpected results of the triplet tracer experiment (TTE) of Russow et al. (Role of nitrite and nitric oxide in the processes of nitrification and denitrification in soil: results from (15)N tracer experiments. Soil Biol Biochem. 2009;41:785-795) the existing SimKIM model was extended to the SimKIM-Advanced model through the addition of three separate nitrite subpools associated with ammonia oxidation, oxidation of organic nitrogen (Norg), and denitrification, respectively. For the TTE, individual treatments with (15)N ammonium, (15)N nitrate, and (15)N nitrite were conducted under oxic, hypoxic, and anoxic conditions, respectively, to clarify the role of nitric oxide as a denitrification intermediate during N2O formation. Using a split nitrite pool, this analysis model explains the observed differences in the (15)N enrichments in nitric oxide (NO) and nitrous oxide (N2O) which occurred in dependence on different oxygen concentrations. The change from oxic over hypoxic to anoxic conditions only marginally increased the NO and N2O release rates (1.3-fold). The analysis using the model revealed that, under oxic and hypoxic conditions, Norg-based N2O production was the dominant pathway, contributing to 90 and 50

  11. Impact of InGaN back barrier layer on performance of AIInN/AlN/GaN MOS-HEMTs

    Science.gov (United States)

    Swain, Sanjit Kumar; Adak, Sarosij; Pati, Sudhansu Kumar; Sarkar, Chandan Kumar

    2016-09-01

    In the present work, we have discussed the effect of InGaN back barrier on device performances of 100 nm gate length AlInN/AlN/GaN metal oxide semiconductor high electron mobility transistor (MOS-HEMT) device and a wide comparison is made with respect to without considering the back barrier layer. The InGaN layer is introduced in the intension to raise the conduction band of GaN buffer with respect to GaN channel so that there is an improvement in the carrier confinement and at the same time witnessed excellent high frequency performance. The simulations are carried out using 2D Sentaurus TCAD simulator using Hydrodynamic mobility model by taking interface traps into consideration. Due to high value of two-dimensional electron gas (2DEG) density and mobility in AlInN/AlN/GaN MOS-HEMT device, higher drain current density is achieved. Simulation are carried out for different device parameters such as transfer characteristic (Id-Vg), transconductance factor (gm), drain induced barrier lowering (DIBL), Subthreshold slope (SS), conduction band energy, transconductance generation factor (gm/Id) and electric field. We have also examined the RF performance such as, total gate capacitance (Cgg), current gain cutoff frequency (fT) and power gain cutoff frequency (fmax) of the proposed devices. Use of InGaN back barrier tends to increase threshold voltage towards more positive value, reduced DIBL, and improves SS and significant growth in (gm/Id) by 5.5%. It also helps to achieve better frequency response like substantial increase in fT up to 91 GHz with current gain 60 dB as compare to 67 GHz with 56 dB for the device without considering back barrier and increase in fmax up to 112 GHz with respect 94 GHz. These results evident that use of InGaN back barrier in such devices can be better solution for future analog and RF applications.

  12. Enhanced Hole Mobility and Density in GaSb Quantum Wells

    Science.gov (United States)

    2013-01-01

    electron-mobility transistors (HEMTs) with InAs channels and AlSb barriers operate at substan- tially lower power than similar circuits based upon GaAs...the XRD scan for sample 4L, the piece labeled L in Fig. 2. The buffer layer consisted of 888 periods of (4.0 s AlSb / 1.0 s AlAs). Peaks are visible...to match the experimental peak positions, and is shown below the experimental data in Fig. 3. The layer thicknesses were 0.33 nm AlAs and 1.30 nm AlSb

  13. Study on the electrical degradation of AlGaN/GaN MIS-HEMTs induced by residual stress of SiNx passivation

    Science.gov (United States)

    Bai, Zhiyuan; Du, Jiangfeng; Liu, Yong; Xin, Qi; Liu, Yang; Yu, Qi

    2017-07-01

    In this paper, we report a new phenomenon in C-V measurement of different gate length MIS-HEMTs, which can be associated with traps character of the AlGaN/GaN interface. The analysis of DC measurement, frequency dependent capacitance-voltage measurements and simulation show that the stress from passivation layer may induce a decrease of drain output current Ids, an increase of on-resistance, serious nonlinearity of transconductance gm, and a new peak of C-V curve. The value of the peak is reduced to zero while the gate length and measure frequency are increasing to 21 μm and 1 MHz, respectively. By using conductance method, the SiNx/GaN interface traps with energy level of EC-0.42 eV to EC-0.45 eV and density of 3.2 × 1012 ∼ 5.0 × 1012 eV-1 cm-2 is obtained after passivation. According to the experimental and simulation results, formation of the acceptor-like traps with concentration of 3 × 1011 cm-2 and energy level of EC-0.37 eV under the gate on AlGaN barrier side of AlGaN/GaN interface is the main reason for the degradation after the passivation. He is currently an Associate Professor with State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Microelectronics and Solid-State Electronics, UESTC. He is the author of over 30 peer-reviewed journal papers and more than 20 conference papers. He has also hold over 20 patents. His research interests include Gallium Nitride based high-voltage power switching devices, microwave and millimeter-wave power devices and integrated technologies. Dr. Yu was a recipient of the prestigious Award of Science and Technology of China

  14. Thirty-five-nm T-Gate In0.52Al0.48As/In0.53Ga0.47As metamorphic HEMTs with an ultrahigh fmax of 610 GHz

    International Nuclear Information System (INIS)

    Choi, Do-Young; Kim, Sung-Ho; Choi, Gil-Bok; Jung, Sung-Woo; Jeong, Yoon-Ha

    2010-01-01

    Thirty-five-nanometer T-gate GaAs-based In 0.52 Al 0.48 As/In 0.53 Ga 0.47 As metamorphic high electron mobility transistors (mHEMTs) are successfully fabricated using a zigzag-shaped T-gate. We obtain a maximum extrinsic transconductance (g m ) of 1060 mS/mm and a maximum oscillation frequency (f max ) of 610 GHz. These superior results are obtained by reducing the T-gate's length to 35 nm without the assistance of a supporting layer and by fabricating a wide-recessed-gate structure. The stand-alone 35-nm T-gate effectively improves the device performance because it doesn't cause additional parasitic capacitances. The wide-recessed-gate structure alleviates impact ionization in the channel, which suppresses the kink effect in the output characteristic and reduces the output conductance (g ds ). In addition, the wide-recessed-gate structure reduces the gate-to-drain capacitance (C gd ); consequently realizing a state-of-the-art f max . The f max of 610 GHz, to our knowledge, is the highest value reported to date for GaAs-based HEMTs.

  15. Culture and identity: Popular culture as characterizing device in Håkan Nesser’s sister novels Kim Novak badade aldrig i Genesarets sjö (1998) and Och Piccadilly Circus ligger inte i Kumla (2002)

    OpenAIRE

    Almgren White, Anette

    2016-01-01

    Nesser’s most popular crime novel Kim Novak and its pendant Piccadilly, set in the 1960’s in Midsweden, share time, location, and the adolescence’s search for identity. In that quest the merging popular culture plays an important role. (Grossberg 1997) Nesser catches the characteristics of the time; Erik, 14 years, reads and writes comics; Mauritz, 17 years, listens to the latest pop music and constantly adds to his album collection. He also writes poetry and reads classics while listening to...

  16. Udjel mlijeka i mliječnih proizvoda u strukturi društveno organiziranog obroka u učeničkim domovima na području grada Zagreba

    OpenAIRE

    Gajdoš, Jasenka; Kurtanjek, Želimir

    1999-01-01

    Zbog velikog udjela proteina, minerala i vitamina, mlijeko spada u skupinu vrlo važnih namirnica tijekom rasta i razvoja mladih. Osobito su važne prehrambene navike pojedinaca. Kako bi se dobio što bolji uvid u prehrambeni status izabrane skupine (djevojke i mladići od 14-18 godina) obavljena je analiza obroka u učeničkim domovima. Iz analiziranih obroka razvidno je što se može poboljšati u obrocima društvene prehrane. Analizom obroka te anketom, utvrđeno je da 62% djevojaka i 66% mladića kon...

  17. On a two-layer Si{sub 3}N{sub 4}/SiO{sub 2} dielectric mask for low-resistance ohmic contacts to AlGaN/GaN HEMTs

    Energy Technology Data Exchange (ETDEWEB)

    Arutyunyan, S. S., E-mail: spartakmain@gmail.com; Pavlov, A. Yu.; Pavlov, B. Yu.; Tomosh, K. N.; Fedorov, Yu. V. [Russian Academy of Sciences, Institute of Ultrahigh Frequency Semiconductor Electronics (Russian Federation)

    2016-08-15

    The fabrication of a two-layer Si{sub 3}N{sub 4}/SiO{sub 2} dielectric mask and features of its application in the technology of non-fired epitaxially grown ohmic contacts for high-power HEMTs on AlGaN/GaN heterostructures are described. The proposed Si{sub 3}N{sub 4}/SiO{sub 2} mask allows the selective epitaxial growth of heavily doped ohmic contacts by nitride molecular-beam epitaxy and the fabrication of non-fired ohmic contacts with a resistance of 0.15–0.2 Ω mm and a smooth surface and edge morphology.

  18. Improvement of drain current of AlGaN/GaN-HEMT through the modification of negative differential conductance (NDC), current collapse, self-heating and optimization of double hetero structure

    Science.gov (United States)

    Basumatary, Bikramjit; Maity, Santanu; Muchahary, Deboraj

    2016-09-01

    For the high-power application, high breakdown voltage of the HEMT device is required that is free from the negative effects such as current collapse and NDC. In this paper, it is found that without any substrate for the higher dimension, the breakdown is larger than the lower dimension. However, it is not free from NDC, which can be eliminated by the shorter channel. Back barrier layer is used to increase this breakdown voltage for the shorter dimension which has given very efficient result, doubling the voltage from 6 V to 13 V for the 'x' composition of 0.3 of AlxGa1-xN and 16 V for AlN back barrier. At the end, the relation of capacitance to the breakdown voltage for the shorter channel is derived, which shows that the breakdown voltage is mostly dependent on the carrier concentration in the lower layer.

  19. LA COMPETITIVIDAD TURÍSTICA DE FOZ DO IGUAÇU SEGÚN LOS DETERMINANTES DEL «INTEGRATIVE MODEL» DE DWYER & KIM: ANALIZANDO LA ESTRATEGIA DE CONSTRUCCIÓN DEL FUTURO

    Directory of Open Access Journals (Sweden)

    José Manoel Gandara

    2013-01-01

    Full Text Available Este artículo analiza estudios turísticos recientes sobre la ciudad de Foz do Iguaçu (Brasil que fueron base de políticas de gestión del destino, bajo la óptica de los determinantes dela competitividad definidos por Dwyer & Kim (2003, en su modelo conceptual «IntegrativeModel». Verifica qué dimensiones, determinantes e indicadores de la competitividad han sidoconsiderados. Los resultados indican que han sido privilegiadas todas las dimensiones de lacompetitividad, con sus determinantes, a pesar de que tales estudios no fueron desarrolladoscon este objetivo y base teórica. Pero, respecto a los indicadores de medidas, la verificaciónempírica no ha agotado la totalidad recomendada.

  20. Baseline characteristics and response to 2 years of growth hormone (GH) replacement of hypopituitary patients with GH deficiency due to adult-onset craniopharyngioma in comparison with patients with nonfunctioning pituitary adenoma: data from KIMS (Pfizer International Metabolic Database).

    Science.gov (United States)

    Verhelst, Johan; Kendall-Taylor, Pat; Erfurth, Eva Marie; Price, David Anthony; Geffner, Mitchell; Koltowska-Häggström, Maria; Jönsson, Peter J; Wilton, Patrick; Abs, Roger

    2005-08-01

    In epidemiological studies, hypopituitary adults show increased mortality compared with population controls. Patients with hypopituitarism caused by a craniopharyngioma (CP) and/or its treatment have a higher mortality than patients with other etiologies, such as a nonfunctioning pituitary adenoma (NFPA). To analyze this difference, we used the KIMS database (Pfizer International Metabolic Database) comparing CP and NFPA patients in terms of baseline characteristics and responses to GH replacement. Baseline characteristics were studied in 351 CP patients (189 men and 162 women; mean age, 42.5 yr) and compared with 370 NFPA patients, matched for age and sex (185 men and 185 women; mean age, 42.5 yr). The effects of 2 yr of GH replacement were analyzed in a subgroup of 183 CP and 209 NFPA patients. At baseline, both CP and NFPA patients had characteristic features of GH deficiency, with low serum IGF-I, increased body fat, dyslipidemia, and reduced quality of life. Male CP patients were significantly more obese (30.0 vs. 28.2 kg/m2; P = 0.0003) compared with NFPA patients, had a higher waist/hip ratio (P = 0.004), higher triglycerides (P = 0.003), and lower high-density lipoprotein cholesterol (P = 0.03). Similar, but much smaller, differences were seen in female CP compared with NFPA patients, only reaching significance for waist/hip ratio (P = 0.05) and triglycerides (P = 0.0004). CP patients had more often undergone surgery by the transcranial route (68.8% vs. 30.9%; P NFPA patients (58.7% vs. 19.8%; P NFPA patients. After 2 yr of GH replacement therapy, similar significant improvements were evident in both groups in fat-free mass, total and low-density lipoprotein cholesterol, and Quality-of-Life-Assessment in GH Deficient Adults score compared with baseline. In contrast to NFPA patients, CP patients had no significant decrease in body fat with GH therapy. In the KIMS database, patients with CP have more often undergone surgery by the transcranial route than

  1. Ajateenistusest, ausalt! / Kim Järvepõld

    Index Scriptorium Estoniae

    Järvepõld, Kim

    2007-01-01

    Ilmunud ka: Postimees : na russkom jazõke, 9. apr. 2007, lk. 7. Autor leiab, et põhiseaduslik nõue, mille järgi on kõik Eesti kodanikud kohustatud osa võtma riigikaitsest, pole vastavuses tegeliku olukorraga, ning arvab, et kohustuslik ajateenistus tuleb kaotada või viia kooskõlla põhiseadusega

  2. GRAMMATICAL ANALYSIS OF INTERLANGUAGE Kim Barker ...

    African Journals Online (AJOL)

    developmentally into seven discrete stages according to research in normal child language .... This highlights a striking feature of both samples, namely the ... a central feature of the inierlanguage produced by the subjects of this study. The most frequenily occurring errors codcd for both stibjects were: o Element omission.

  3. Influence of the Thickness of the Barrier Layer in Nanoheterostructures and the Gate-Drain Capacitance on the Microwave and Noise Parameters of Field-Effect AlGaN/GaN HEMT

    Science.gov (United States)

    Mikhaylovich, S. V.; Fedorov, Yu. V.

    2016-07-01

    We perform a computational and analytical study of how the thickness of the barrier layer in nanoheterostructures and the gate-drain capacitance C gd influence the microwave parameters (limiting frequency of current amplification and maximum generation frequency) and noise parameters (noise factor) of a field-effect AlGaN/GaN high electron mobility transistor. The results of complex measurements of the parameters of such transistors based on nanoheterostructures with a barrier layer thickness of 3.5-15.7 nm, which were performed within the framework of four technological routes in the range 0.1-67 GHz, are presented. It is shown that in order to reduce the noise ratio and improve the microwave parameters, it is necessary to optimize both the parameters of nanoheterostructures and the manufacturing techniques. In particular, the thickness of the barrier layer should be reduced, and the gate length should be chosen such as to maximize the product of the squared maximum current amplification frequency in the interior of the transistor and the output impedance between the drain and the source. Additionally, attention should be given to the shape of the gate to reduce the capacitance C gd. Under certain conditions of manufacture of nitride field-effect HEMT, one can achieve a lower noise factor compared with the transistors based on arsenide nanoheterostructures.

  4. Selective wet-etching of InGaAs on InAlAs using adipic acid and its application to InAlAs/InGaAs HEMTs

    Science.gov (United States)

    Higuchi, K.; Uchiyama, H.; Shiota, T.; Kudo, M.; Mishima, T.

    1997-04-01

    Highly selective wet-etching of InGaAs on InAlAs was demonstrated using pH-controlled adipic acid, 0268-1242/12/4/024/img1 and 0268-1242/12/4/024/img2 solutions. A maximum selectivity of 250 was obtained by controlling the InGaAs and InAlAs etching mechanisms. By identifying the rate-determining steps for the etching of InAlAs and InGaAs, we found that the high selectivity is due to the difference in solubility between the oxide of InAlAs and that of InGaAs in the adipic acid solution. InAlAs/InGaAs HEMTs fabricated in a 0268-1242/12/4/024/img3 diameter wafer by using this highly selective etching had a threshold voltage and a transconductance with standard deviations of 38 mV and 0268-1242/12/4/024/img4, respectively.

  5. Fatma Barbarosoğlu’nun Hikâyelerine Yansıyan Kadın Kimliği The Women Identity Which Is Reflected In The Stories Of Fatma Barbarosoğlu

    Directory of Open Access Journals (Sweden)

    Alpay Doğan YILDIZ

    2012-12-01

    Full Text Available Fatma Barbarosoğlu has a different personality with writer herself. She has sociologist, storyteller, novelist, essayist, andcolumnist in newspaperwithwriterherself. Her sociologist personality’s firstbook is a Moda ve Zihniyet. She published this book in 1995. Shewroteanotherbookwith her personality. Her second book’s the Acı ve Deniz is a storybook and published in 1996. Mrs. Barbarosoğlupublished Acı Deniz with her 5 book inside of 10 years: Acı Deniz (1996, Gün Akşamsızdır (2000, Senin Hikâyen (2001, Ahir Zaman Gülüşleri (2002, İki Kişilik Rüyalar (2005. Shetakecognizanceofessay during these years.Fatma Barbarosoğlupublished 4essaybookmore of withintheseyear. Shebegansowrite a novelafter 2005.Aftershewrote of firstbook is Hiçbiryer her threenovelbecomefamous…Fatma Barbarosoğlu is one of theconsiderableauthors ofTurkishshortstoryafter 1990. Theauthorpublishedfiveshortstorybooksbetween the years 1996 and 2005. Thecharacters of FatmaBarbarosoğluliveduringtheyearstheshortstoriesarewritten, inotherwords, mostly in post-1990 period of Turkey.Thetopicslikepeople’sneed of narrating, lack of communication, lostmoral values, imagecentered life perception, author-reader-societyrelationship arediscussed. However, one of themostnotableissue is“woman”. Fatma Barbarosoğluconsidersthewoman inthesocietywithvariouskinds of identitieslikewife, mother,workingwoman, friendandstudent. Inthisarticle, thewomanidentities intheshortstories of theauthorwill be consideredcomprehensively. Fatma Barbarosoğlu, yazar olarak değişik kimliklere sahiptir. 0; sosyolog, hikâyeci, romancı, deneme yazarı, gazetede köşe yazarı… kimliklerine sahiptir. 1995’te yayımladığı ilk kitabı Moda ve Zihniyet sosyolog kimliğinin ürünüdür. Bu kimlikle başka kitaplar da yazmıştır. Yazarın ikinci eseri olan Acı Deniz bir hikâye kitabıdır ve 1996 yılında yayımlanır. Barbarosoğlu, sonraki yaklaşık on yıllık sürede Ac

  6. El individuo en el cambio: la transformación de las relaciones bilaterales entre la República de Corea y la República Popular Democrática de Corea, bajo la figura del presidente surcoreano Kim Dae-Jung

    OpenAIRE

    Perilla Moreno, Jairo Andrés

    2017-01-01

    Este artículo busca interpretar el proceso mediante el cual las ideas y presupuestos políticos y sociales del expresidente surcoreano Kim Dae-Jung, permitieron una transformación significativa de las relaciones bilaterales entre Corea del Sur y Corea del Norte, durante su periodo presidencial entre los años 1998 y 2003. Inicialmente, dichas relaciones estuvieron caracterizadas por una incesante tensión militar como resultado de la Guerra de Corea, escenario dentro del cual apareció la figura ...

  7. RAZLIKE U MOTORIČKIM SPOSOBNOSTIMA BOKSERA I NESPORTISTA

    Directory of Open Access Journals (Sweden)

    Benin Murić

    2011-03-01

    Full Text Available This research was conducted with the aim to define differences in motor abilities and morphological characteristics between judists and non/athletes of the same age. Sample encompassed 120 subjects having 60 students non/athletes and 60 students actively engaged in sports. For the evaluation of motor abilities there were conducted 12 measuring instruments. Testing of the posted hypotheses was performed on the basis of statistical data. The obtained results of this research in motor area have shown that there is statistically significant difference between selected boxsers and students not going in for box. This difference is defined by significantly better values and results in motor tests performed by the selected boxers.

  8. [Recent books on international law] / Yoonie Kim, Paul R Williams

    Index Scriptorium Estoniae

    Kim, Yoonie

    2005-01-01

    Arvustus: Lauri Mälksoo. Illegal Annexation and State Continuity : The Case of the Incorporation of the Baltic States by the USSR. Study of the Tension between Normativity and Power in International Law. Leiden ; Boston, 2003

  9. Adamantan, ugradbena jedinica u makrocikličkim sustavima

    Directory of Open Access Journals (Sweden)

    Vujasinović, I.

    2007-03-01

    Full Text Available Part of our investigation was directed to the synthesis of novel macrocyclic polyethers, which contain polycyclic cage molecule, incorporated into the macrocyclic framework or attached as a side chain. We have prepared a series of adamantane-functionalized oxa-, aza- and thia-crown ethers, and studied their complexation abilities by alkali or transition metal picrate extraction experiments or by electrospray ionization mass spectrometry. In the homogeneous methanol/chloroform solutions as well as, in the extractions of metals from aqueous solution by macrocycles in chloroform, it was found that the type of heteroatom (O, N, S and presence the adamantanesubstituents, influence the metal selectivity as well as the overall lipophilicity of the macrocyclic ligand.

  10. Belarus - a unique case in the European context? / Kim Lausten

    Index Scriptorium Estoniae

    Lausten, Kim

    2003-01-01

    Valgevene presidendi Aleksander Lukashenko autoritaarsest režiimist, sellega seonduvatest võimalikest ohtudest Valgevene naaberriikide julgeolekule. Autor analüüsib Lukashenko režiimi institutsioonilisi ning sotsiaalpoliitilisi tagamaid

  11. Respiratory arrest caused by a large uterine myoma | Kim | South ...

    African Journals Online (AJOL)

    Large abdominal masses increase intra-abdominal pressure, thus changing the haemodynamics of the patient by elevating the diaphragm and causing partial occlusion of the inferior vena cava (IVC). Large abdominal masses present many challenges, including life-threatening risks due to severe cardiovascular, ...

  12. Application of Hosaka and DJ Kim Whatmann paper protocols for ...

    African Journals Online (AJOL)

    unpublished) were tested on cowpea line IT06K-5-83 under different conditions. The results revealed that both methods with modifications can work with cowpea. However, Hosaka (2004) method seems to be more promising than the other ...

  13. MICROBIOLOGICAL STUDY OF CORNEAL ULCERS AT KIMS, AMALAPURAM

    OpenAIRE

    Padmaja; Nageswara Rao

    2014-01-01

    Corneal ulcers are the common cause of corneal blindness. Of the corneal ulcers, majority of the cases are because of the fungal etiology. The present study is aimed to identify the pathogenic organisms responsible for corneal infections. Majority of the cases are secondary to trauma. Of the fungal cases, Aspergillus is found to be the predominant fungus affecting corneal ulcers, followed by bacteria affecting the corneal ulcers.

  14. Reliability Investigation of GaN HEMTs for MMICs Applications

    Directory of Open Access Journals (Sweden)

    Alessandro Chini

    2014-08-01

    Full Text Available Results obtained during the evaluation of radio frequency (RF reliability carried out on several devices fabricated with different epi-structure and field-plate geometries will be presented and discussed. Devices without a field-plate structure experienced a more severe degradation when compared to their counterparts while no significant correlation has been observed with respect of the different epi-structure tested. RF stress induced two main changes in the device electrical characteristics, i.e., an increase in drain current dispersion and a reduction in gate-leakage currents. Both of these phenomena can be explained by assuming a density increase of an acceptor trap located beneath the gate contact and in the device barrier layer. Numerical simulations carried out with the aim of supporting the proposed mechanism will also be presented.

  15. Matematika u vojnotehničkim dostignućima / Mathematics in military-technical achievements

    Directory of Open Access Journals (Sweden)

    Natalija B. Jelenković

    2010-10-01

    Full Text Available Matematika se definiše kao vrsta filozofije ili pogleda na svet, sredstvo za razvijanje apstraktnog mišljenja, a služi i za pojednostavljenje prirodnih nauka. Prilično je specijalna - izučava količinu i poredak; uopšteno, to je nauka o formalnim strukturama. Ona je i kombinacija slobode kreativne misli i strogih logičkih pravila, ali i deduktivna nauka koja daje pravila i zakone pomoću kojih baratamo brojevima i prostorom. Kao takva, matematika je i savremeni alat za vojnotehnička dostignuća modernog doba, kao što su: sve vrste radio i radio-relejnih veza, radarska sredstva, sredstva za upravljanje, navigaciju, televizijska, optoelektronska, hidro- akustična sredstva, sredstva za protivelektronsku borbu, kao i mnoga elektronska tehnička sredstava, naoružanje i vojna oprema Kopnene vojske, Vazduhoplovstva i protiv-vazduhoplovne odbrane, Ratne mornarice. Prethodno istaknute definicije matematike su korišćene kao osnova za uopšteno sistematizovano izlaganje metodom uporednog opisivanja, nabrajanjem činjenica, definisanjem pojmova. Cilj članka je da se na osnovu nabrojanja postojećih primena matematike i proširivanjem znanja može dalje napredovati u istraživanju mnogih vojnih oblasti. Pored toga, članak ima i pedagoški cilj, a to je da kroz opise i karakteristike sredstava ratne tehnike zainteresuje i afirmiše značaj i lepotu vojnog poziva. Rezultati razvoja informacionih tehnologija su, pored ostalog, i savršenija vojnotehnička dostignuća, a predstavljaju i inspiraciju za mnoge inovacije i uspehe. / In this article, mathematics is dealt with as a science necessary for the design, development and implementation of certain military-technical achievements such as many electronic devices, smart missiles, miniature antennas, camouflage military clothing and other military equipment. Some areas of applied, discrete and continuous mathematics are underlined in particular. Application of mathematics The importance of mathematics for military-technical achievements is reflected in the fact that mathematics allowed the existence and development of military disciplines such as: fortifications, military statistics, military economics, cryptography, military psychology, air force, military-technical and military information science. There are also many applications using mathematical models and linear programming. Mathematics is thus necessary and indispensable as a tool, a way of expression and communication, as well as the basic creation of further progress. This article reveals the connection of mathematics and certain military areas that are important for the development of the armed forces and war materiel. The application of mathematics in military- technical achievements is entailed in the connection of mathematics with military disciplines. Information technology - Basic concepts Some identified problems occurring in military purposes are mentioned through some basic concepts and benefits related to information technology. Comparative description and listing of characteristic traits resulting in the noticed and given advantages and disadvantages highlighted the creation of information technologies, first by using conventional programs and programming and then by using artificial intelligence and expert systems.

  16. Dr Jung Hyun KIM Vice Minister for Education, Science and Technology MEST Republic of Korea

    CERN Multimedia

    Jean-Claude Gadmer

    2010-01-01

    He learnt about CERN's LHC computing grid project from Frédéric Hemmer, head of the information technology department. In addition, the vice-minister toured the ATLAS visitor centre, the CMS control centre, the ALICE experiment's exhibition and control room, and he met Korean scientists at CERN.

  17. Systemically applied insecticides for treatment of erythrina gall wasp, quadrastichus erythrinae kim hymenoptera: Eulophidae

    Science.gov (United States)

    Doccola, J.J.; Smith, S.L.; Strom, B.L.; Medeiros, A.C.; Von Allmen, E.

    2009-01-01

    Abstract The erythrina gall wasp (EGW), believed native to Africa, is a recently described species and now serious invasive pest of Erythrina (coral trees) in tropical and subtropical locales. Erythrina are favored ornamental and landscape trees, as well as native members of threatened ecosystems. The EGW is a tiny, highly mobile, highly invasive wasp that deforms (galls) host trees causing severe defoliation and tree death. The first detection of EGW in the United States was in O'ahu, Hawai'i in April 2005. It quickly spread through the Hawai'ian island chain (U.S.) killing ornamental and native Erythrina in as little as two years. At risk are endemic populations of Erythrinaas well as ornamental landscape species in the same genus, the latter of which have already been killed and removed from O'ahu at a cost of more than USD $1 million. Because EGW are so small and spread so quickly, host injury is usually detected before adult wasps are observed, making prophylactic treatments less likely than therapeutic ones. This study evaluates two stem-injected insecticides, imidacloprid (IMA-jet??) and emamectin benzoate, delivered through Arborjet Tree I.V.?? equipment, for their ability to affect E. sandwicensis (wiliwili) canopy demise under severe EGW exposure. IMA-jet, applied at a rate of 0.16 g AI/cm basal diameter (0.4 g AI/in. dia.), was the only effective treatment for maintaining canopy condition of wiliwili trees. Emamectin benzoate, applied at a rate of -0.1 g AI/cm basal diameter (-0.25 g AI/in. dia.), was not effective in this application, although it was intermediate in effect between IMA-jet and untreated trees. The relatively high concentrations of imidacloprid in leaves, and its durability for at least 13 months in native wiliwili growing on a natural, dryland site, suggest that treatment applications against EGW can impact canopy recovery even under suboptimal site and tree conditions. ?? 2009 International Society of Arboriculture.

  18. Projecting Pyongyang: The Future of North Korea's Kim Jong IL Regime

    National Research Council Canada - National Science Library

    Scobell, Andrew

    2008-01-01

    .... It does not consider the future of North Korea as a geographic or territorial entity. Some analysts and observers discuss the future without clarifying whether they are discussing the country of North Korea or the Pyongyang regime...

  19. A study of wisdom Psalms in the Old Testament / by Yeol Kim

    OpenAIRE

    Kim, Yeol

    2008-01-01

    This thesis was an attempt to read the wisdom psalms in the Old Testament more effectively. In the introduction, the problems identified in the research on wisdom psalms were analyzed along the history of investigation into wisdom psalms. According to investigation, the main problems of the research of wisdom psalms can be summarized in three main aspects. The first research problem mainly lies in the negligence of the careful reading of the content of wisdom psalms. While most scholars are b...

  20. The role of relA and spoT in Yersinia pestis KIM5 pathogenicity.

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2009-08-01

    Full Text Available The ppGpp molecule is part of a highly conserved regulatory system for mediating the growth response to various environmental conditions. This mechanism may represent a common strategy whereby pathogens such as Yersinia pestis, the causative agent of plague, regulate the virulence gene programs required for invasion, survival and persistence within host cells to match the capacity for growth. The products of the relA and spoT genes carry out ppGpp synthesis. To investigate the role of ppGpp on growth, protein synthesis, gene expression and virulence, we constructed a Delta relA Delta spoT Y. pestis mutant. The mutant was no longer able to synthesize ppGpp in response to amino acid or carbon starvation, as expected. We also found that it exhibited several novel phenotypes, including a reduced growth rate and autoaggregation at 26 degrees C. In addition, there was a reduction in the level of secretion of key virulence proteins and the mutant was > 1,000-fold less virulent than its wild-type parent strain. Mice vaccinated subcutaneously (s.c. with 2.5x10(4 CFU of the Delta relA Delta spoT mutant developed high anti-Y. pestis serum IgG titers, were completely protected against s.c. challenge with 1.5x10(5 CFU of virulent Y. pestis and partially protected (60% survival against pulmonary challenge with 2.0x10(4 CFU of virulent Y. pestis. Our results indicate that ppGpp represents an important virulence determinant in Y. pestis and the Delta relA Delta spoT mutant strain is a promising vaccine candidate to provide protection against plague.

  1. Kim Siebenhüner, Bigamie und Inquisition in Italien 1600-1750 - recenze

    Czech Academy of Sciences Publication Activity Database

    Blažek, Pavel

    2008-01-01

    Roč. 106, č. 1 (2008), s. 184-186 ISSN 0862-6111 Institutional research plan: CEZ:AV0Z90090514 Keywords : Polygamy * marriage * inquisition * early modern period Subject RIV: AA - Philosophy ; Religion

  2. Production of Recombinant Injectosome and Outer Membrane Proteins from Yersinia Pestis KIM5

    Science.gov (United States)

    2009-06-01

    respectively. Ligation Mix • 0.5 uL (0.025 ug/uL) pCR2.1 vector • 1.5 uL 10x ligation buffer • 6 uL Water • 1 uL T4 DNA ligase • 6 uL purified...uL T4 DNA ligase diluted 1/10 3.3.8 Transform plasmids into the non-selective, non-expression E. coli strain DH5α and verify with restriction...be produced from lymphocyte mRNA coding for the VHH domains from the Camelid antibodies, and these will be used as a phage display to screen for the

  3. Rak izletshim u 80 iz 100 zabolevshihh detei / Lev Durnov ; interv. Kim Smirnov

    Index Scriptorium Estoniae

    Durnov, Lev

    1999-01-01

    Intervjuu Venemaa N. Blohhini nimelise Onkoloogia Teadusliku Keskuse peadirektori asetäitja Lev Durnoviga keskuseLaste Onkoloogia ja Hematoloogia Teadusliku Uurimise Instituudi tööst laste vähktõve ravimisel

  4. Hlapivi spojevi arome dalmatinske pancete proizvedene u različitim tehnološkim uvjetima

    OpenAIRE

    Krvavica, Marina; Milak, Vedrana

    2017-01-01

    Cilj ovog istraživanja bio je utvrditi u kojoj mjeri razlike u načinu soljenja (sa ili bez aditiva, utrošak soli/salamure, duljina faze soljenja), načinu dimljenja (ložište unutar ili izvan objekta i temperatura dima) te duljina sušenja i zrenja, utječu na sastav hlapivih spojeva arome dalmatinske pancete. U navedenu svrhu uzeta su po 2 uzorka dalmatinske pancete iz dva različita preradbena objekta na području Dalmacije, u kojima je panceta proizvedena na sljedeći način: objekt A – salamurenj...

  5. TIP ORGANIZACIJE GRUPE U KOŠARKAŠKIM TIMOVIMA 1. LIGE SRBIJE I CRNE GORE

    Directory of Open Access Journals (Sweden)

    Igor Vučković

    2006-06-01

    Full Text Available In this study were analysed the differences between better placed and worse placed teams of the First basketaball league of Serbia and Montenegro in The type of group organization. The aim was to see in which type of group organization (extrovert or introvert mentioned teams belong, and then to relate it with the final position of their team on the standing. After discriminant analysis it was concluded that there are significant differences between better placed and worse placed teams in The type of group organization with the benefit of the better placed teams.

  6. LOŠA PRAKSA U SLOŽENIM INFORMATIČKIM PROJEKTIMA

    OpenAIRE

    Visković, Dominik; Varga, Mladen

    2008-01-01

    Složeni informatički projekti, kao što su projekti razvoja informacijskog sustava ili implementacije ERP-a, često su neuspješni zbog lošeg upravljanja projektom, neprimjerenog metodološkog pristupa ili neuvažavanja dobre prakse. U članku se razmatraju tipične i često ponavljanje greške u odvijanju informatičkih projekata, tzv. postupci loše prakse te opisuju načini njihova izbjegavanja. Postupci loše prakse izraz su upravljačkih, metodoloških i komunikacijskih problema koje tijekom projekta t...

  7. The New North Korean Problem: History and Responsibilities in the Age of Kim Jong Un

    Science.gov (United States)

    2012-03-29

    16. PRICE CODE: N/A 17. SECURITY CLASSIFICATION OF REPORT UNCLASSIFIED 18. SECURITY CLASSIFICATION OF THIS PAGE...US President George W. Bush in 2002, North Korea has accepted its status and used it to its advantage. In the late 2000s, the threat has been...desperately needed it. The political elite were the only ones who could afford rice and any type of meat . 35 In 2005, the WFP and various NGOs were

  8. Reclassification of Bifidobacterium stercoris Kim et al. 2010 as a later heterotypic synonym of Bifidobacterium adolescentis

    Czech Academy of Sciences Publication Activity Database

    Killer, Jiří; Sedláček, I.; Rada, V.; Havlík, J.; Kopečný, Jan

    2013-01-01

    Roč. 63, Pt 11 (2013), s. 4350-4353 ISSN 1466-5026 R&D Projects: GA ČR(CZ) GAP304/11/1252 Institutional support: RVO:67985904 Keywords : bacterial strain * Bifidobacterium Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 2.798, year: 2013

  9. Type 2-diabetes--en heterogen sygdom med kim i fostertilstanden

    DEFF Research Database (Denmark)

    Vaag, Allan

    2012-01-01

    Type 2 diabetes (T2D) is a heterogeneous disease with a multifactorial aetiology involving defects in the pancreatic beta cells, liver, muscles, adipose tissue, guts, brain, kidneys and heart. While genetics may only explain a minor proportion of T2D, the contribution of an adverse intrauterine e...

  10. Sinise ookeani strateegia : konkurentsi vältimise kunst / W. Chan Kim, Renee Mauborgne

    Index Scriptorium Estoniae

    Kim, W. Chan, 1952-

    2006-01-01

    Sinise ookeani strateegia õpetab, kuidas tegutseda konkurentidest vabal turul. Kommenteerib Hansapanga juhatuse esimees Erkki Raasuke. Lisad: Sinine ookean Tartus; Punane ookean versus sinine ookean. Tabel: Sinise ookeani loomise ajaloost

  11. Zaznavanje in prepoznavanje logotipov na vozilih z računalniškim vidom

    OpenAIRE

    TOMAŽIČ, GAŠPER

    2015-01-01

    V tem diplomskem delu se posvečamo zaznavanju in prepoznavanju avtomobilskih logotipov v slikah. Kot osrednji del predlagamo postopek za detekcijo logotipov, ki temelji na odkrivanju regij MSER v sliki. Iz teh regij sestavimo kandidate za avtomobilski logotip, jih opišemo s histogramom orientacij gradientov ter z naključnimi gozdovi določimo, ali kandidatna regija predstavlja logotip, in če, kateri. Predlagali smo tudi izboljšave postopka z uporabo alternativnih barvnih prostorov, geometrijsk...

  12. Primena GIS-a u hidrološkim istraživanjima - primer reke Lepenice

    Directory of Open Access Journals (Sweden)

    Milanović Ana

    2007-01-01

    Full Text Available The basic component of GIS technology (Geographical Information Systems is the base of graphical data, which can be used for geographical definition of spaces elements- entities. As a new, modern, technology, it has more application in different hydrological researches. In GIS creation Lepenica river basin, it was applied softwares: Micro Station, GeoMedia, Surfer 7. Map and AutoCAD. After data base creation, it was enabled for users to get different information of Lepenica river basin on the simple way. Getting data are used for creation of three thematic maps (altitude zones map, hydrographical net map and precipitation isoline map.

  13. Pečati na antičkim opekama i krovnim crepovima iz Sotina (Cornacum)

    OpenAIRE

    Ilkić, Mato

    2005-01-01

    Sotin, about ten kilometers south-east from Vukovar, in antiquity was the site of Cornacum, one of the most important Roman military bases of the Croatian Danubian limes. Until now there has been no systematic archaeological excavation in Sotin which would provide an answer to the most important questions concerning Cornacum. These questions concern the problems of its position, the division between military and civil zones, and the period when the main fortifications were built and who built...

  14. ZnO HEMTs on Flexible Substrates for Large Area Monolithic Antenna Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — AMBP Tech will implement Zinc Oxide high mobility material technology it has developed specifically for flexible electronics into a direct write process onto large...

  15. Increase of the electron mobility in HEMT heterostructures with composite spacers containing AlAs nanolayers

    Energy Technology Data Exchange (ETDEWEB)

    Vinichenko, A. N., E-mail: vanaxel@gmail.com; Gladkov, V. P.; Kargin, N. I.; Strikhanov, M. N.; Vasil’evskii, I. S. [National Research Nuclear University “MEPhI” (Russian Federation)

    2014-12-15

    The effect of the hybridization of quantum states on electron transport in a two-barrier quantum well δ-doped through a spacer layer at the limit of heavy doping is shown theoretically and experimentally. A method for increasing the electron mobility in the quantum well by suppressing the tunnel coupling with the donor region through the introduction of an AlAs nanobarrier into the spacer layer is proposed. It is experimentally shown that, in the samples with a shallow quantum well, the AlAs nanobarrier introduced into the spacer layer provides a larger than threefold increase in the electron mobility at low temperatures.

  16. Conduction, reverse conduction and switching characteristics of GaN E-HEMT

    DEFF Research Database (Denmark)

    Sørensen, Charlie; Lindblad Fogsgaard, Martin; Christiansen, Michael Noe

    2015-01-01

    In this paper switching and conduction characterization of the GS66508P-E03 650V enhancement mode gallium nitride (GaN) transistor is described. GaN transistors are leading edge technology and as so, their characteristics are less than well documented. The switching characteristics are found using...

  17. Study of Radiation Hardness of Lattice Matched AlInN/GaN HEMT Heterostructures

    Science.gov (United States)

    2016-10-01

    theoretically chemical isotope resolution capability and atomic spatial resolution. As such, atom probe tomography is potentially uniquely capable...Furthermore, this would lead to measurement artifacts because the ions would not be accelerated across the electric field in the manner expected, which...electric field and lead to an artifact spectrum such as the one shown in Figure 7, where most of the peaks cannot be identified. Eventually, adjustments

  18. An Error Analysis of Hot Electron Temperatures Collected from Cross Sectioned GaN HEMTs (Preprint)

    Science.gov (United States)

    2017-07-03

    FIG. 1. When plotted together, the five emission spectra demonstrate the experimental reproducibility of the data col- lection system. III. RESULTS... Emission spectra were collected from a set of five de- vices over a photon energy range of 1.0 eV to 3.0 eV. The raw data collected from these devices...desired reliability models. We report here on the extraction of hot electron temperatures from electroluminescence spectra , which is attributed to

  19. Recessed insulator and barrier AlGaN/GaN HEMT: A novel structure ...

    Indian Academy of Sciences (India)

    2017-03-08

    Mar 8, 2017 ... dimensional ATLAS device simulator. Gate length reduction can be used to improve the transconductance and gate capacitance in a transistor. However, it is worth noting that decrease in gate length causes short channel effects such as drain-induced barrier lowering. (DIBL). DIBL is an effect that changes ...

  20. Small signal modeling of AlGaN/GaN HEMTs with consideration of CPW capacitances

    International Nuclear Information System (INIS)

    Du Jiangfeng; Wang Kang; Yin Chenggong; Liu Yang; Yu Qi; Xu Peng; Feng Zhihong; Dun Shaobo

    2015-01-01

    Given the coplanar waveguide (CPW) effect on AlGaN/GaN high electron mobility transistors at a high frequency, the traditional equivalent circuit model cannot accurately describe the electrical characteristics of the device. The admittance of CPW capacitances is large when the frequency is higher than 40 GHz; its impact on the device cannot be ignored. In this study, a small-signal equivalent circuit model considering CPW capacitance is provided. To verify the model, S-parameters are obtained from the modeling and measurements. A good agreement is observed between the simulation and measurement results, indicating the reliability of the model. (paper)

  1. Effect of annealing on sheet carrier density of AlGaN/GaN HEMT structure

    Science.gov (United States)

    Chen, Nie-Chuan; Tseng, Chien-Yuan; Lin, Hsin-Tung

    2009-01-01

    The effects of surface state on sheet carrier density in the Al 0.17Ga 0.83N/GaN heterostructure were investigated. The sheet carrier density obtained by Hall measurement was 1.803×10 13 e/cm 2. However, this value was inconsistent with the capacitance-voltage ( C- V) measurements. This carrier density varied with the surface conditions of the samples that were prepared for Hall and C- V measurements. To study further the effects of the surface conditions on the sheet carrier densities, the samples were annealed at various temperatures and then characterized by Hall and work function measurements. The carrier densities increased with annealing temperatures. Meanwhile, the work functions decreased. Accordingly, the relationship between the surface states and the sheet carrier densities was determined.

  2. Small signal modeling of AlGaN/GaN HEMTs with consideration of CPW capacitances

    Science.gov (United States)

    Jiangfeng, Du; Peng, Xu; Kang, Wang; Chenggong, Yin; Yang, Liu; Zhihong, Feng; Shaobo, Dun; Qi, Yu

    2015-03-01

    Given the coplanar waveguide (CPW) effect on AlGaN/GaN high electron mobility transistors at a high frequency, the traditional equivalent circuit model cannot accurately describe the electrical characteristics of the device. The admittance of CPW capacitances is large when the frequency is higher than 40 GHz; its impact on the device cannot be ignored. In this study, a small-signal equivalent circuit model considering CPW capacitance is provided. To verify the model, S-parameters are obtained from the modeling and measurements. A good agreement is observed between the simulation and measurement results, indicating the reliability of the model. Project supported by the National Natural Science Foundation of China (Nos. 61376078, 61274086) and the Fundamental Research Funds for the Central Universities of China (No. ZYGX2012J041).

  3. Control of epitaxial defects for optimal AlGaN/GaN HEMT performance and reliability

    Science.gov (United States)

    Green, D. S.; Gibb, S. R.; Hosse, B.; Vetury, R.; Grider, D. E.; Smart, J. A.

    2004-12-01

    High-quality GaN epitaxy continues to be challenged by the lack of matched substrates. Threading dislocations that result from heteroepitaxy are responsible for leakage currents, trapping effects, and may adversely affect device reliability. We have studied the impact of AlN nucleation conditions on the density and character of threading dislocations on SiC substrates. Variation of the nucleation temperature, V/III ratio, and thickness are seen to have a dramatic effect on the balance between edge, screw and mixed character dislocation densities. Electrical and structural properties have been assessed by AFM and XRD on a material level and through DC and RF performance at the device level. The ratio between dislocation characteristics has been established primarily through comparison of symmetric and asymmetric XRD rocking curve widths. The effect of each dislocation type on leakage current, RF power and reliability at 2 GHz, the targeted band for cell phone infrastructure applications, is discussed.

  4. Recessed insulator and barrier AlGaN/GaN HEMT: A novel structure ...

    Indian Academy of Sciences (India)

    2017-03-08

    drain capacitance, short channel effects and DC ... (Tr) of the recessed region of the barrier at the source side are the same as those of the insulator at the drain side. ..... produces a vertical electric field on the carriers moving.

  5. Thermal Modeling of GaN HEMTs on Sapphire and Diamond

    National Research Council Canada - National Science Library

    Salm, III, Roman P

    2005-01-01

    ... to diamond through the use of commercially available Silvaco software for modeling and simulation. The unparalleled thermal properties of diamond are expected to dramatically decrease device temperatures and increase component lifetimes and reliability.

  6. AlGaN/GaN-based HEMT on SiC substrate for microwave ...

    Indian Academy of Sciences (India)

    THe two-dimensional electron gas (2DEG) transport properties are discussed by solving Schödinger and Poison equations self-consistently resulting in various subbands having electron eigenvalues. From DC characteristics, the saturation drain currents are measured to be 600 mA/mm and 550 mA/mm for Si3N4 and SiO2 ...

  7. RBS channeling measurement of damage annealing in InAs/AlSb HEMT structures

    International Nuclear Information System (INIS)

    Hallén, Anders; Moschetti, Giuseppe

    2014-01-01

    Electrical isolation of InAs/AlSb high electron mobility transistors has been achieved by the ion implantation isolation technique. The multilayered structures are grown by molecular beam epitaxy on GaAs substrates. The optimal isolation is provided by damaging patterned areas by 100 keV Ar ions implanted at room temperature using fluence of 2 × 10 15 cm −2 , and then annealing the samples in 365 °C for 30 min. The damage build-up and annealing is studied by channeling Rutherford backscattering spectrometry (RBS) and compared to sheet resistance measurements. Only a low level of damage annealing can be seen in RBS for the post-implant annealed samples, but for Ar fluence higher than 2 × 10 14 cm −2 , a strong electrical resistivity increase can still be achieved

  8. RBS channeling measurement of damage annealing in InAs/AlSb HEMT structures

    Energy Technology Data Exchange (ETDEWEB)

    Hallén, Anders, E-mail: ahallen@kth.se [KTH Royal Institute of Technology, ICT, P.O. Box Electrum 229, SE 164 40 Kista (Sweden); Moschetti, Giuseppe [Chalmers University of Technology, Microtechnology and Nanoscience-MC2, SE-412 96 Gothenburg (Sweden)

    2014-08-01

    Electrical isolation of InAs/AlSb high electron mobility transistors has been achieved by the ion implantation isolation technique. The multilayered structures are grown by molecular beam epitaxy on GaAs substrates. The optimal isolation is provided by damaging patterned areas by 100 keV Ar ions implanted at room temperature using fluence of 2 × 10{sup 15} cm{sup −2}, and then annealing the samples in 365 °C for 30 min. The damage build-up and annealing is studied by channeling Rutherford backscattering spectrometry (RBS) and compared to sheet resistance measurements. Only a low level of damage annealing can be seen in RBS for the post-implant annealed samples, but for Ar fluence higher than 2 × 10{sup 14} cm{sup −2}, a strong electrical resistivity increase can still be achieved.

  9. Report on the Second KIMS-CNA Conference: The PLA Navys Build-Up and ROK-USN Cooperation

    Science.gov (United States)

    2009-02-01

    Michael A. McDevitt CRM D0019742.A1/Final February 2009 Strategic Studies is a division of CNA. This directorate...or Southeast Asia. If these routes were no longer cheap or safe, ships would use other routes, such as the Straits of Lombok and Makassar, or even...catid=&topic=10 5 Noer and Gregory: “Chokepoints: Maritime Economic Concerns in Southeast Asia. ”CNA Publications No. CRM 2796000700 and 2796000709

  10. Savremene metode analize ulja u tehničkim sistemima / Modern methods of oil analysis in technical systems

    Directory of Open Access Journals (Sweden)

    Sreten R. Perić

    2010-01-01

    Full Text Available Analiza ulja na osnovu pravilno definisanog programa predstavlja veoma efikasan metod monitoringa stanja tehničkih sistema koji obezbeđuje rane upozoravajuće znake potencijalnih problema, koji vode ka otkazu i zastoju tehničkih sistema. Ova analiza je veoma efikasan alat programa za monitoring stanja tehničkih sistema. Mnogobrojni uređaji i testovi za analizu ulja omogućavaju kvalitetan monitoring i dijagnosticiranje problema koji nastaju u procesu podmazivanja. Korišćenjem programa za analizu motornih ulja: skraćuje se neplanirano vreme otkaza vozila, poboljšava pouzdanost vozila, produžava radni vek motora, optimizira interval zamene ulja i smanjuju troškovi održavanja vozila. / Different technical systems require an appropriate lubricant to be used at an appropriate place, at appropriate time and in appropriate quantity. Determination of technical systems condition has a very important role in the development of theory and practice of friction, wear and lubrication. Lubricant is, as a contact element of tribomechanical systems, a carrier of information about the state of the whole system, from the aspect of tribological and other ageing processes. The analysis of oils, based on a properly defined program, thus represents a very effective method for monitoring the condition of technical systems, which ensures early warning signals of potential problems that could lead to failure and break down of technical systems. Introduction It is not always simple to determine a type of lubricant, frequency of lubrication and the quantity of lubricant to be used. The optimal recommendation would be to follow specifications of technical system manufacturers, experience, lab research or professional recommendation of lubricant suppliers. Rational lubricant consumption can be obtained by timely oil replacement, which then enables a maximum possible period of use as well as high-quality lubrication. Since the primary role of lubricants is to reduce negative effects of tribological processes related to friction, wear and temperature increase in tribomechanical systems, all types of maintenance include lubrication as a very important part of the whole procedure. On the other hand, lubricant is, as a contact element of the system, a carrier of information about the condition of the whole system, from the aspect of tribological and other ageing processes. Therefore, an analysis of oils, based on a properly defined program, represents a very effective method for monitoring the condition of technical systems, which ensures early warning signals of potential problems that could lead to failure and break down of technical systems. Besides mechanical components in a system structure, the condition of lubricant itself is also affected, which leads to a loss of lubricating properties. Contamination and degradation of lubricating oils There are numerous opportunities for contamination and degradation of lubricating oils. Contamination and degradation of oil exploitation cannot be completely prevented, but can be significantly reduced, which is very important both for oil and for a technical system itself. The rate and degree of degradation of oil are proportional to the rate and extent of contamination. It is therefore important to prevent rapid contamination of oil, before and during use. The spectrum of oil contaminants is considerably wide. Any contaminant destructive impact on oil, reducing its physical-chemical and working properties, results in shortening its service life as well as the service life of the technical system in question. During oil exploitation, changes occur in: chemical compositions and properties of base oils, chemical compositions and properties of additives, and consequently chemical compositions of oils in general, as a result of contamination and degradation. The most significant oil contaminants are base oils degradation products, additives degradation products, metal particles as a result of wear processes, solid particles from the environment, water and products of fuel combustion. During the operation the following changes occur: contamination of oil by the products of its own degradation, by products of incomplete combustion of fuel and by contaminants of various origin. The main objectives of the analysis and monitoring of oil exploitation in vehicles The main objectives of the analysis and monitoring of oil exploitation in vehicles are: - analysis of system element wear processes, - analysis of lubricant contamination processes, - monitoring changes in the properties of lubricants in order to optimize the life of system functionality control (penetration of contaminants, temperature and pressure, filter efficiency, etc. and - determining the extent of damage and causes of failure. The analysis of the contents of different metals in lubricants is very important. Metal particles are abrasive, and act as catalysts in oil oxidation. In motor oils, they can originate from additives, wear processes, fuel, air and cooling liquid. Metals from additives may be Zn, Ca, Ba, or Mg and they indicate additive deterioration. Metals originating from wear are: Fe, Pb, Cu, Cr, Al, Mn, Ag, Sn, and they point to increased wear in these systems. The elements originating from cooling liquids are Na and B, and their increased content indicates the penetration of cooling liquid in the lubricant. The increased content of Si or Ca, which originate from the air, points to a malfunction of the air filter. Condition monitoring through oil analysis tests There are many different types of oil analysis tests that are used to evaluate lubricants. The tests must cover three areas: technical system condition, contamination condition, and lubricant condition. From the technical system condition aspect, attention should be paid to the presence of any metal particles in oil and the tendencies in their change. The second focus would be the lubricant condition, especially viscosity change, increase in oxidation, and signs of additive depletion. The third focus would be impurities, where the emphasis should be placed on particle number, water content and metal impurities. Theoretically, oil analyses are divided into three classes. In reality, all three condition-monitoring classes are interrelated and must be considered as a whole. For example, an increase in viscosity could be an indication that a lubricant is oxidizing. But oxidation could be an incorrect conclusion, if there is no indication of an increasing oxidation tendency obtained either by the acid number (AN values analysis or the Fourier Transform-Infrared (FT-IR analysis. Lubricant monitoring enables its refreshing or replacement before serious technical system damage occurs. If damage is noticed in the course of operation, and is caused by impurities or lubricant problems, the technical system condition can be monitored and the system may be shut down immediately to minimize damage. There are the two types of alarms, i.e. warning signs used in oil analysis: absolute and statistical alarms. An effective oil analysis relies on the combination of both types. The warning limit is the absolute alarm. The statistical tendency takes into account variability based on oil sampling and its contamination and represents the standard deviation. The deviation from the normal variability indicates serious problems, which is the first signal for taking action and dealing with the problem. As the deviation tendency approaches the warning limit, oil replacement, oil purification or a system inspection is required. Metal particles content and viscosity or some other parameters can be tested. The normal variability range takes into account minor variations caused by analytical accuracy, sample homogeneity, etc. Statistical alarms, which provide the earliest possible warning without false alarms, are difficult to achieve. The factors such as oil adding or changing, filter changes and a sampling technique can distort the results. The following tests are most frequently used in technical system condition monitoring: - Spectrometric Analysis, - Analytical Ferrography, - Rotrode Filter Spectroscopy (RFS, - Infrared Analysis (FT-IR, - Viscosity, - Total acid number (TAN, - Total Base Number (TBN - Water and Particle Count.

  11. Growth of a plasmid-bearing (pYV) Yersinia pestis KIM5 in retail raw ground pork

    Science.gov (United States)

    Yersinia pestis can cause oro-pharyngeal plague as a result of consumption or handling of meat from infected animals. Thus, food naturally or intentionally contaminated can have a role in the dissemination of human plague. The growth of a conditionally virulent plasmid (pYV)-bearing rifampicin-res...

  12. ANALYSIS OF CORNEAL ASTIGMATISM BEFORE AND AFTER PTERYGIUM SURGERY- A PROSPECTIVE STUDY IN PATIENTS ATTENDING KIMS, HUBLI

    Directory of Open Access Journals (Sweden)

    Y. B. Bajantri

    2017-10-01

    Full Text Available BACKGROUND Pterygium is a very common degenerative condition seen in Indian subcontinent. It is a wing-shaped fibrovascular encroaching up on the cornea from either sides. The prevalence rate is 5.2%. Pterygium is known to affect refractive astigmatism. The induced astigmatism may become significant to cause visual distortion, even though the pterygium remains distant from visual axis induced astigmatism maybe either “with-the-rule” or “against-the-rule.” The aim of the study is to- 1. Compare preoperative with postoperative astigmatism in case of pterygium. 2. Assess the amount of astigmatism in case of pterygia of different lengths measured from the limbus over the cornea. MATERIALS AND METHODS The study included 70 eyes of 70 patients with primary pterygium. Preoperative evaluation included pterygium size, visual acuity, keratometry and refraction with subjective correction. Patients included in the study were divided into three groups based on length of pterygium encroaching on cornea (1 to 2 mm, 2 to 3 mm, >3 mm. Each eye underwent bare sclera pterygium excision. Postoperative visual acuity, keratometry and refraction were evaluated on 1st day, at the end of 1st week, 4 th week and 9th week. The pre and postoperative results were compared and analysed. RESULTS An average of all 70 cases with mean pterygium length 3.2 mm had a mean keratometry astigmatism of 1.84 ± 0.89D preoperatively and 0.514 ± 0.52D postoperatively indicating a reduction of pterygium-induced corneal astigmatism by 1.45 ± 0.77D (p value <0.0001, which was statistically significant. CONCLUSION Pterygium-induced corneal astigmatism is directly proportional to the size of the pterygium. Thus, early surgical excision reduces the corneal astigmatism, and hence, improves the visual acuity.

  13. VizieR Online Data Catalog: Low-resolution near-infrared stellar spectra from CIBER (Kim+, 2017)

    Science.gov (United States)

    Kim, M. G.; Lee, H. M.; Arai, T.; Bock, J.; Cooray, A.; Jeong, W.-S.; Kim, S. J.; Korngut, P.; Lanz, A.; Lee, D. H.; Lee, M. G.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Onishi, Y.; Shirahata, M.; Smidt, J.; Tsumura, K.; Yamamura, I.; Zemcov, M.

    2017-06-01

    We present flux-calibrated near-infrared spectra of 105 stars from 0.8{skin, we do not use the first flight data in this work. The star spectral types are determined by fitting known spectral templates to the measured LRS spectra. We use the Infrared Telescope Facility (IRTF) and Pickles 1998 (Cat. J/PASP/110/863) templates for the SED fitting. The SpeX instrument installed on the IRTF observed stars using a medium-resolution spectrograph (R=2000). The template library contains spectra for 210 cool stars (F to M type) with wavelength coverage from 0.8 to 2.5μm (Cushing 2005ApJ...623.1115C; Rayner 2009ApJS..185..289R). The Pickles library is a synthetic spectral library that combines spectral data from various observations to achieve wavelength coverage from the UV (0.115μm) to the near-infrared (2.5μm). It contains 131 spectral templates for all star types (i.e., O to M type) with a uniform sampling interval of 5Å. (6 data files).

  14. Support for harmful treatment and reduction of empathy toward blacks: "Remnants" of stereotype activation involving Hurricane Katrina and "Lil' Kim"

    NARCIS (Netherlands)

    Johnson, J.D.; Bushman, B.J.

    2008-01-01

    Two experiments involving White participants tested the influence of media-based Black stereotypes on subsequent responses to Black and White persons-in-need. Experiment 1 showed that priming the "Black criminal" stereotype through exposure to photographs of Blacks looting after Hurricane Katrina

  15. PROMENE KRVNOG PRITISKA U TOKU TESTA FIZIČKIM OPTEREĆENJEM KOD NORMOTENZIVNIH I HIPERTENZIVNIH REKREATIVACA

    Directory of Open Access Journals (Sweden)

    Mirko Šaranović

    2008-08-01

    Full Text Available Background. Arterial hypertension is a leading cause of morbidity in developed countries. It often decreases functional capacities of the cardiovascular system. Changes of pressure during physical exercise are a very significant a prognostic factor. Aim. The aim of this investigation was to assess changes of blood pressure and heart rate during exercise in normotensive and hypertensive men involved in recreational physical activity. Methods. The study included 90 young men (aged 30-40 years involved in recreation (60 with hypertension, 30 with normal pressure. The bicycle ergometer test was performed after rest, the load increased gradually from 50 to 125W. Blood pressure and heart rate were measured at rest and during the exercise. Results. Systolic and diastolic pressure increased signifi cantly in both groups during the ergometry test, compared to the values at rest. This increase was higher among hypertensive men for every graduation of test load (p<0.05. Heart rate was similar in both groups at rest, but higher values were noted among hypertensive men (p<0.05.

  16. North Korean Leadership Dynamics and Decision-making under Kim Jong-un: A First Year Assessment

    Science.gov (United States)

    2013-09-01

    in the mid-1950s with the unveiling of a Marxist- Leninist model for self -reliance called Juche. It became the principal ideology for politics... Esteem Down through Generations. The 90-minute fourth installment of the official documen- tary film series chronicled the death and funerary rites of...the Politburo established the State Physical Sports and Culture Commission, a 32-member organi- zation which will manage sports and athletics in North

  17. Estimation of spawning area of Pisodonophis sangjuensis Ji and Kim, 2011 (Pisces: Ophichthidae) based on leptocephali size and distribution

    Science.gov (United States)

    Ji, Hwan-Sung; Hwang, Kangseok; Choi, Jung Hwa; Cha, Hyung-Kee; Kim, Jin-Koo

    2017-06-01

    Pre-metamorphic leptocephali of Pisodonophis sangjuensis ( n = 91, 10.4-90.2 mm in total length, TL) were collected in the East China Sea for the first time. Pre-metamorphic leptocephali of P. sangjuensis, which were identified using mitochondrial DNA cytochrome c oxidase subunit I gene (mtDNA COI), are characterized by various combinations of morphological characters: 8 moderate to pronounced gut loops with the kidney terminating on the 6-7th loops; and 8 subcutaneous pigment patches on the tail just ventral to the notochord. Pisodonophis sangjuensis leptocephali were more numerously collected offshore than inshore around Jeju Island. The smallest leptocephali (south far from Jeju Island, and the largest leptocephali (> 100.0 mm TL) were collected from around Jeju Island and the southern coast of Korea. Our findings indicate that P. sangjuensis spawns offshore south of Jeju Island that is an area associated with high water temperature, and then the hatched leptocephali are transported to Jeju Island or the southern coast of Korea by the Tsushima Warm Current.

  18. Effect of Variation of Silicon Nitride Passivation Layer on Electron Irradiated Aluminum Gallium Nitride/Gallium Nitride HEMT Structures

    Science.gov (United States)

    2014-06-19

    1.071 x 1013 , ↓ 24% 1.425 ↓ 57% 200E0 200 200 Å 0 1547 1.42x 1013 3.5 200E1 200 200 Å 1016 cm-2 695 ↓ 55% 1.23 x 1013 .865 ↓ 75% 500E0...Klein, P. B., and Kazior, T. E.. “Trapping effects in GaN and SiC microwave FETs.” Proceedings of the IEEE , 90, no. 6 (2002): 1048-1058. Borchi, E...34 IEEE 252 Transactions on Nuclear Science, 46, no. 4 (1999): 834. Calleja, E., Sánchez, F. J., Basak, D., Sánchez-García, M. A., Muñoz, E

  19. Influence of the device geometry on the Schottky gate characteristics of AlGaN/GaN HEMTs

    International Nuclear Information System (INIS)

    Lu, C Y; Chang, E Y; Bahat-Treidel, E; Hilt, O; Lossy, R; Chaturvedi, N; Würfl, J; Tränkle, G

    2010-01-01

    In this work, we investigate the relevance of device geometry to the Schottky gate characteristics of AlGaN/GaN high electron mobility transistors. Changes of three-terminal gate turn-on voltage and gate leakage current on the gate—drain spacing, source—gate spacing and recess depth have been observed. Further examinations comparing device simulations and measurements suggest that gate turn-on voltage is influenced by the distribution of electric potential under the gate region which is related to the geometry. By proper design of the device, high gate turn-on voltage can be obtained for both depletion-mode and recessed enhancement-mode devices

  20. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy

    Science.gov (United States)

    Bagnall, Kevin R.; Wang, Evelyn N.

    2016-06-01

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E2 high and A1 (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the inverse piezoelectric effect in wurtzite GaN, which has been predicted theoretically in zinc blende gallium arsenide (GaAs).

  1. Measuring the thermal conductivity of the GaN buffer layer in AlGaN/GaN HEMTs

    OpenAIRE

    Power, Maire; Pomeroy, James W; Otoki, Yohei; Tanaka, Takeshi; Wada, Jiro; Kuzuhara, Masaaki; Jantz, Wolfgang; Souzis, Andrew; Kuball, Martin H H

    2015-01-01

    The thermal conductivity of the GaN buffer layer in AlGaN/GaN devices can be determined by measuring the vertical temperature gradient through this layer. In this work, diamond micro-thermometers and standard micro-Raman thermography were used to determine the surface and volumetric depth average temperature, respectively, of the carbon-doped GaN buffer layer in AlGaN/GaN transistors. By comparing measured temperatures with finite element thermal simulation, a thermal conductivity of 200 ± 20...

  2. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bagnall, Kevin R.; Wang, Evelyn N. [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-06-15

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E{sub 2} high and A{sub 1} (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the inverse piezoelectric effect in wurtzite GaN, which has been predicted theoretically in zinc blende gallium arsenide (GaAs).

  3. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy

    International Nuclear Information System (INIS)

    Bagnall, Kevin R.; Wang, Evelyn N.

    2016-01-01

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E 2 high and A 1 (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the inverse piezoelectric effect in wurtzite GaN, which has been predicted theoretically in zinc blende gallium arsenide (GaAs).

  4. A Novel Extraction Approach of Extrinsic and Intrinsic Parameters of InGaAs/GaN pHEMTs

    Science.gov (United States)

    2015-07-01

    1995. [2] Q. Fan, J. Leach , and H. Mork circuit modeling for AlGaN/GaN method for determining circuit elem Proc. IEEE, vol.98, no. 7, pp. 1140 [3] W...microwave and RF circuits . Many approaches have been proposed in the last few decades for the extraction of small signal equivalent circuit parameters...ECPs), among which optimization based parameter extraction methods are commonly used due to their flexibility to various equivalent circuit

  5. RELACIJE ANTROPOMETRIJSKIH KARAKTERISTIKA I KOGNITIVNIH SPOSOBNOSTI SA SITUACIONO-MOTORIČKIM INFORMACIJAMA U KOŠARCI KOD 15-to GODIŠNJAKA

    Directory of Open Access Journals (Sweden)

    Bećir Šabotić

    2005-05-01

    Full Text Available Today it is known an enormous number of games which regularly organize sport competitions. The most popular of them are included into the program of the Olympic Games, where basketball takes very important place because of its popularity. Basketball is a sport of higher achievement (first-class sport, sport fun as well as the important means of active rest and recovery (of recreation and of course one of the most powerful means of physical education. The examination is attended to 247 persons who are being examined from the first grade of secondary schools in Novi Pazar, Tutin and Rožaje communities. The goal of the examination was to prove the relation between the set of predictorical variables (anthropometrical characteristics and cognitive capabilities on one hand and set of variables of criterion of situationally-motorical capabilities in basketball on the other hand. The canonically correlational analyze is being applied for the management of special points. As it was expected, the canonically correlational analyze has shown that there is an important connection between the group of variables for the evaluation of anthropometrical characteristics and cognitive capabilities and the group of variables for the evaluation of situationally-motorical capabilities in basketball. By analyzing the correspondent canonical functions it is being directed at the assumption that the success of the performance of specific motorical movements in basketball at most depends on the longitudinal dimensionality of the skeleton, and from the body mass of the person we are examining. By examining the assumption it is confirmed that the cognitive capabilities influence on the success in overcoming the points in basketball that are given. The author concludes that the person we have examined with given results in anthropometrical characteristics and higher degree of intelligence will achieve better results in specific motorical tests in basketball. These results are logical in consideration of structure when performing the elements in basketball that demand quick moves and good coordination which is directly connected with intelligence. Besides, that given results will have use in order to come to premature selection in sport games, that will say in basketball.

  6. First experience under the exemption regime of EC Regulation 1228/2003 on Conditions for Access to the Network of Cross-Border Exchanges in Electricity / Kim Talus

    Index Scriptorium Estoniae

    Talus, Kim

    2005-01-01

    23. aprillil 2005 Euroopa Komisjoni poolt vastu võetud otsusest anda roheline tuli Estlink'i projektile, mis tähendab koostööd Eesti ja Soome elektrivõrkude vahel ; Euroopa Komisjon võttis aluseks regulatsiooni nr. 1228/2003 artikli 7

  7. A. Kim, k.f. Anderson, j. Berliner, j. Hassan, j. Jensen, h.j. Mertz, h. Pietsch, a. Rao, R. Scherer, and a. Sutterfield.

    Science.gov (United States)

    Kim, A; Anderson, K F; Berliner, J; Hassan, J; Jensen, J; Mertz, H J; Pietsch, H; Rao, A; Scherer, R; Sutterfield, A

    2003-10-01

    In this study, three dummies were evaluated on the component level and as a whole. Their responses were compared with available volunteer and embalmed Post Mortem Human Subject (PMHS) data obtained under similar test conditions to evaluate their biofidelity. The volunteer and PMHS data, used as comparators in this study, were used previously to establish some of the biofidelity requirements of the Hybrid III. The BioRID II, the Hybrid III, and the RID2 were all subjected to rear impact HYGE sled tests with deltaVs of 17 and 28 km/hr to determine their biofidelity in these conditions. A static pull test, where a load was manually applied to the head of each dummy, was used to evaluate the static strength of their necks in flexion and extension. Finally, pendulum tests were conducted with the Hybrid III and RID2 to evaluate the dynamic characteristics of their necks in flexion and extension. The sled test results indicate that out of the three dummies, the overall flexibility of the Hybrid III is comparable to that of the volunteer anticipating the impact. The overall flexibilities of the BioRID II and the RID2 are greater than those of all the comparators used in this study (the tensed volunteer and the two embalmed PMHSs). The responses of the Hybrid III are closer to those of the tensed volunteer than those of the PMHSs. The responses of the BioRID II and the RID2 are closer to those of the PMHSs than to the tensed volunteer.

  8. The Past as Prologue: President Kim Dae Jung’s Legacy and President Roh Moo Hyun’s Policy Issues and Future Challenges

    Science.gov (United States)

    2005-01-01

    alleged corruption and incompetence. It succeeded in forcing as many as 15 of incumbents out of the National Assembly at that time. Bearing this... corruption by severing close ties between the big business and the government 153 Elsewhere I...more open, and globalized society, which demonstrated its achievements worldwide during the co-hosting of the Soccer World Cup and the Busan Asia Games

  9. Whole-genome sequencing reveals that Shewanella haliotis Kim et al. 2007 can be considered a later heterotypic synonym of Shewanella algae Simidu et al. 1990.

    Science.gov (United States)

    Szeinbaum, Nadia; Kellum, Cailin E; Glass, Jennifer B; Janda, J Michael; DiChristina, Thomas J

    2018-04-01

    Previously, experimental DNA-DNA hybridization (DDH) between Shewanellahaliotis JCM 14758 T and Shewanellaalgae JCM 21037 T had suggested that the two strains could be considered different species, despite minimal phenotypic differences. The recent isolation of Shewanella sp. MN-01, with 99 % 16S rRNA gene identity to S. algae and S. haliotis, revealed a potential taxonomic problem between these two species. In this study, we reassessed the nomenclature of S. haliotis and S. algae using available whole-genome sequences. The whole-genome sequence of S. haliotis JCM 14758 T and ten S. algae strains showed ≥97.7 % average nucleotide identity and >78.9 % digital DDH, clearly above the recommended species thresholds. According to the rules of priority and in view of the results obtained, S. haliotis is to be considered a later heterotypic synonym of S. algae. Because the whole-genome sequence of Shewanella sp. strain MN-01 shares >99 % ANI with S. algae JCM 14758 T , it can be confidently identified as S. algae.

  10. Upotreba Kaizen filozofije u upravljačkim strukturama kompanija u Srbiji / The Use of Keizen Philosophy in the Managing Structures in the Companies in Serbia

    Directory of Open Access Journals (Sweden)

    Simona Žikić

    2016-11-01

    Full Text Available In the moment when there is a question mark over the economy of every country and the markets are not stable, but ever changing, moving forward, and/or collapsing, one of the most successful approaches to the survival and improvement of the management of the companies is Keizen concept. Keizen concept of management is philosophy that is initially used in Japan, where it comes from, but in other places all around the world as well, mostly in America and the countries in Western civilization. Keizen philosophy is the concept of continuous improvement, which, strategically observed, contributes improvement and prosperity of the companies. Having in mind its occurrence, the first results of Keizen philosophy’s approach can be identified in the development of Japanese economy, which reached unbelievable results and improvement only few years after the Second World War. Japanese companies very soon became competitive at the global market thanks to Kaizen philosophy, no matter the fact that his approach includes managing concepts and concepts of business organization which are diametrically opposite to the current dominant opinion and application of the concepts of managing business organization from the Western companies. This is the reason why the idea of this paper is to show the main values that are in the core of Kaizen philosophy and to show that the application of this business  concept is possible in Serbia, besides the small number of those who already did it. The aim of this paper is to bring closer the importance of the development of human resources and their influence on the structure of the companies’ management, because only with the human resources department based well, there is a possibility of Keizen philosophy application.

  11. Introductory Statement by Won-Soo Kim [International Conference on Nuclear Security: Commitments and Actions, Vienna (Austria), 5-9 December 2016

    International Nuclear Information System (INIS)

    Kim, Won-Soo

    2017-01-01

    We need to treat WMD risks and threats holistically. Lessons learned in one area can be emulated in another. The IAEA has learned valuable lessons through its own emergency management work and partnership with other UN agencies, including through the UN Counter-Terrorism Implementation Task Force. These lessons could be beneficial in developing response mechanisms for biological incidents.

  12. Review of: Carol M. Richardson, Kim W. Woods and Michael W. Franklin (eds, Renaissance Art Reconsidered: An Anthology of Primar y Sources,

    Directory of Open Access Journals (Sweden)

    Eugenia Drakopoulou

    2017-02-01

    Full Text Available The title of this volume refers to the course of the Open University entitled Renaissance Art Reconsidered and more particularly to its three course books, which reflect three reference fields in the modern history of art: the method and arduous work of making works of art; the centres of art production, the trade networks and the relations between artists and clients; and the means of viewing art, whether in the context of religious practice, theory or patronage, during the fifteenth and early sixteenth centuries.

  13. High sensitivity Hall devices with AlSb/InAs quantum well structures

    International Nuclear Information System (INIS)

    Zhang Yang; Zhang Yu-Wei; Wang Cheng-Yan; Guan Min; Cui Li-Jie; Li Yi-Yang; Wang Bao-Qiang; Zhu Zhan-Ping; Zeng Yi-Ping

    2013-01-01

    AlSb/InAs quantum well (QW) structures and InAs films on GaAs (001) substrates were grown by molecular beam epitaxy (MBE). We investigated the dependence of electron mobility and two-dimensional electron gas (2DEG) concentration on the thickness of an InAs channel. It is found that electron mobility as high as 19050 cm 2 · V −1 · s −1 has been achieved for an InAs channel of 22.5 nm. The Hall devices with high sensitivity and good temperature stability were fabricated based on the AlSb/InAs QW structures. Their sensitivity is markedly superior to Hall devices of InAs films. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  14. Quantitative strain and compositional studies of InxGa1-xAs Epilayer in a GaAs-based pHEMT device structure by TEM techniques.

    Science.gov (United States)

    Sridhara Rao, Duggi V; Sankarasubramanian, Ramachandran; Muraleedharan, Kuttanellore; Mehrtens, Thorsten; Rosenauer, Andreas; Banerjee, Dipankar

    2014-08-01

    In GaAs-based pseudomorphic high-electron mobility transistor device structures, strain and composition of the In x Ga1-x As channel layer are very important as they influence the electronic properties of these devices. In this context, transmission electron microscopy techniques such as (002) dark-field imaging, high-resolution transmission electron microscopy (HRTEM) imaging, scanning transmission electron microscopy-high angle annular dark field (STEM-HAADF) imaging and selected area diffraction, are useful. A quantitative comparative study using these techniques is relevant for assessing the merits and limitations of the respective techniques. In this article, we have investigated strain and composition of the In x Ga1-x As layer with the mentioned techniques and compared the results. The HRTEM images were investigated with strain state analysis. The indium content in this layer was quantified by HAADF imaging and correlated with STEM simulations. The studies showed that the In x Ga1-x As channel layer was pseudomorphically grown leading to tetragonal strain along the [001] growth direction and that the average indium content (x) in the epilayer is ~0.12. We found consistency in the results obtained using various methods of analysis.

  15. A physics based compact model of I?V and C?V characteristics in AlGaN/GaN HEMT devices

    Science.gov (United States)

    Khandelwal, Sourabh; Fjeldly, T. A.

    2012-10-01

    In this paper we present a physics-based compact model for drain current Id and intrinsic gate-drain and gate-source capacitances CGS and CGD in AlGaN/GaN high electron mobility transistors. An analytical expression for the 2-DEG charge density ns, valid in all the regions of device operation is developed and applied to derive current and capacitances. The drain current model includes important physical effects like velocity saturation, channel length modulation, short channel effect, mobility degradation effect, and self-heating. The expression for ns is used to derive a model for CGS and CGD applicable in all the regions of device operation. The parameters introduced in the model have a clear link to the physical effects facilitating easy extraction of parameter values. The model is in excellent agreement with experimental data for both drain current and capacitances over a typical range of applied voltages and device geometries.

  16. MEASUREMENT OF PHONON TRANSPORT IN GaN-ON-SiC AND GaN-ON-DIAMOND HIGH ELECTRON MOBILITY TRANSISTOR (HEMT) DEVICES

    Science.gov (United States)

    2017-10-16

    DARPA) or the U.S. Government. Report contains color . 14. ABSTRACT The objective of this project is to experimentally study the transient non...Conductivity as a Function of Phonon Mean Free Path............. 11 Figure 6: Schematic of TDTR Measurement...investigate the non-diffusive phonon transport.From density functional theory (DFT) based Boltzman transport equation (BTE), phonon mean free paths

  17. A Feasibility Study of UV Laser Assisted 3D-Atom Probe Analysis of AlGaN/GaN HEMTs

    Science.gov (United States)

    2013-03-05

    Field evaporation of Air Force Research Laboratory AlGaN/GaN high electron mobility transistors was attempted using a 3-D atom probe system with a...343nm UV wavelength laser. Previous attempts to analyze these samples using a Local Electrode Atom Probe system with a 532nm wavelength laser were...exhibit poor electrical and thermal properties like the wide bandgap AlGaN/GaN epilayers have been successfully. However, in this study every atom probe tip

  18. Surface stoichiometry modification and improved DC/RF characteristics by plasma treated and annealed AlGaN/GaN HEMTs

    Science.gov (United States)

    Upadhyay, Bhanu B.; Takhar, Kuldeep; Jha, Jaya; Ganguly, Swaroop; Saha, Dipankar

    2018-03-01

    We demonstrate that N2 and O2 plasma treatment followed by rapid thermal annealing leads to surface stoichiometry modification in a AlGaN/GaN high electron mobility transistor. Both the source/drain access and gate regions respond positively improving the transistor characteristics albeit to different extents. Characterizations indicate that the surface show the characteristics of that of a higher band-gap material like AlxOy and GaxOy along with N-vacancy in the sub-surface region. The N-vacancy leads to an increased two-dimensional electron gas density. The formation of oxides lead to a reduced gate leakage current and surface passivation. The DC characteristics show increased transconductance, saturation drain current, ON/OFF current ratio, sub-threshold swing and lower ON resistance by a factor of 2.9, 2.0, 103.3 , 2.3, and 2.1, respectively. The RF characteristics show an increase in unity current gain frequency by a factor of 1.7 for a 500 nm channel length device.

  19. Influence of a BGaN back-barrier on DC and dynamic performances of an AlGaN/GaN HEMT: simulation study

    Science.gov (United States)

    Guenineche, Lotfi; Hamdoune, Abdelkader

    2016-05-01

    In this paper, we study the effect of a BGaN back-barrier on the DC and RF performances of an AlGaN/GaN high electron mobility transistor. Using TCAD Silvaco, we examine some variations of thickness and boron concentration in the BGaN back-barrier layer. First, we fix the thickness of the back-barrier layer at 5 nm and we vary the concentration of the boron in BGaN from 1% to 4%. Second, we fix the concentration of the boron in BGaN to only 2% and we vary the thickness of the back-barrier layer from 20 nm to 110 nm. The BGaN back-barrier layer creates an electrostatic barrier under the channel layer and improves the performances of the device by improving the electron confinement in the two-dimensional electron gas. The DC and AC characteristics are improved, respectively, by a greater concentration of boron and by a thicker BGaN layer. For 4% boron concentration and 5 nm thick back-barrier layer, we obtain a maximum drain current of 1.1 A, a maximum transconductance of 480 mS mm-1, a cut-off frequency of 119 GHz, and a maximum oscillation frequency of 311 GHz.

  20. Catalyseur d'hydrocraquage à base de sulfure de NiMo déposé sur une zéolithe HEMT modifiée

    Science.gov (United States)

    Baalala, M.; Becue, T.; Leglise, J.; Manoli, J. M.; van Gestel, J. N. M.; Lamotte, J.; Bensitel, M.; Goupil, J. M.; Cornet, D.

    1999-02-01

    Treating a NH4EMT zeolite with a solution of (NH4)2SiF6 at 80 °C affords a solid containing amorphous SiO2 intimately mixed with the zeolite. This acidic support EMT-Si was loaded with NiMo sulfide in order to prepare a bifunctional catalyst, which was tested for the hydrogenation of benzene and the hydrocracking of n-heptane. This NiMo/EMT-Si catalyst was found more active for hydrogenation than the analogous NiMo/HY. This is ascribed to a higher dispersion of the NiMo sulfide, which is almost equally shared between the internal mesopores in the modified EMT solid, and the fissures, which were created throughout the zeolite grains upon inserting the NiMo sulfide. The catalyst with the EMT-Si support was also found more active than the NiMo/HY for the hydrocracking of heptane, with a slightly higher selectivity into heptane isomers. Le traitement d'une zéolithe NH4EMT par une solution de (NH4)2SiF6 fournit un solide comportant une phase SiO2 amorphe intimement mélangée aux parties intactes de la zéolithe. Sur ce support acide EMT-Si, on a greffé un sulfure de NiMo afin de préparer un catalyseur bifonctionnel qui a été testé dans les réactions d'hydrogénation du benzène et d'hydrocraquage du n-heptane. Ce catalyseur NiMo/EMT-Si s'avère plus actif en hydrogénation que son analogue NiMo/HY, en raison d'une meilleure dispersion du sulfure de NiMo. Sur le solide EMT modifié, le sulfure se répartit à peu près également entre les mésopores internes et les fissures crées dans les grains de zéolithe lors de l'insertion du sulfure de NiMo. Au contraire sur le support Y, une partie du sulfure est externe aux grains de zéolithe et inactive en catalyse. Le catalyseur NiMo/EMT-Si est aussi trouvé plus actif que le NiMo/HY en hydrocraquage du n-heptane, et un peu plus sélectif en isomères.

  1. Radiation Hard Multichannel AlN/GaN HEMT for High Efficiency X- and Ka-Band Power Amplifiers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This project is directed to the development of low-loss, high power-density Aluminum Nitride (AlN)/Gallium Nitride (GaN) heterostructure based transistors for...

  2. Growth and characterization of AlGaN/GaN/AlGaN double-heterojunction high-electron-mobility transistors on 100-mm Si(111) using ammonia-molecular beam epitaxy

    Science.gov (United States)

    Ravikiran, L.; Dharmarasu, N.; Radhakrishnan, K.; Agrawal, M.; Yiding, Lin; Arulkumaran, S.; Vicknesh, S.; Ng, G. I.

    2015-01-01

    To improve the confinement of two-dimensional electron gas (2DEG) in AlGaN/GaN high electron mobility transistor (HEMT) heterostructures, AlGaN/GaN/AlGaN double heterojunction HEMT (DH-HEMT) heterostructures were grown using ammonia-MBE on 100-mm Si substrate. Prior to the growth, single heterojunction HEMT (SH-HEMT) and DH-HEMT heterostructures were simulated using Poisson-Schrödinger equations. From simulations, an AlGaN buffer with "Al" mole fraction of 10% in the DH-HEMT was identified to result in both higher 2DEG concentration (˜1013 cm-2) and improved 2DEG confinement in the channel. Hence, this composition was considered for the growth of the buffer in the DH-HEMT heterostructure. Hall measurements showed a room temperature 2DEG mobility of 1510 cm2/V.s and a sheet carrier concentration (ns) of 0.97 × 1013 cm-2 for the DH-HEMT structure, while they are 1310 cm2/V.s and 1.09 × 1013 cm-2, respectively, for the SH-HEMT. Capacitance-voltage measurements confirmed the improvement in the confinement of 2DEG in the DH-HEMT heterostructure, which helped in the enhancement of its room temperature mobility. DH-HEMT showed 3 times higher buffer break-down voltage compared to SH-HEMT, while both devices showed almost similar drain current density. Small signal RF measurements on the DH-HEMT showed a unity current-gain cut-off frequency (fT) and maximum oscillation frequency (fmax) of 22 and 25 GHz, respectively. Thus, overall, DH-HEMT heterostructure was found to be advantageous due to its higher buffer break-down voltages compared to SH-HEMT heterostructure.

  3. Growth and characterization of AlGaN/GaN/AlGaN double-heterojunction high-electron-mobility transistors on 100-mm Si(111) using ammonia-molecular beam epitaxy

    International Nuclear Information System (INIS)

    Ravikiran, L.; Radhakrishnan, K.; Yiding, Lin; Ng, G. I.; Dharmarasu, N.; Agrawal, M.; Arulkumaran, S.; Vicknesh, S.

    2015-01-01

    To improve the confinement of two-dimensional electron gas (2DEG) in AlGaN/GaN high electron mobility transistor (HEMT) heterostructures, AlGaN/GaN/AlGaN double heterojunction HEMT (DH-HEMT) heterostructures were grown using ammonia-MBE on 100-mm Si substrate. Prior to the growth, single heterojunction HEMT (SH-HEMT) and DH-HEMT heterostructures were simulated using Poisson-Schrödinger equations. From simulations, an AlGaN buffer with “Al” mole fraction of 10% in the DH-HEMT was identified to result in both higher 2DEG concentration (∼10 13  cm −2 ) and improved 2DEG confinement in the channel. Hence, this composition was considered for the growth of the buffer in the DH-HEMT heterostructure. Hall measurements showed a room temperature 2DEG mobility of 1510 cm 2 /V.s and a sheet carrier concentration (n s ) of 0.97 × 10 13  cm −2 for the DH-HEMT structure, while they are 1310 cm 2 /V.s and 1.09 × 10 13  cm −2 , respectively, for the SH-HEMT. Capacitance-voltage measurements confirmed the improvement in the confinement of 2DEG in the DH-HEMT heterostructure, which helped in the enhancement of its room temperature mobility. DH-HEMT showed 3 times higher buffer break-down voltage compared to SH-HEMT, while both devices showed almost similar drain current density. Small signal RF measurements on the DH-HEMT showed a unity current-gain cut-off frequency (f T ) and maximum oscillation frequency (f max ) of 22 and 25 GHz, respectively. Thus, overall, DH-HEMT heterostructure was found to be advantageous due to its higher buffer break-down voltages compared to SH-HEMT heterostructure

  4. Report on the KIMS-CNA Conference (2nd): The PLA Navy’s Build-Up and ROK-USN Cooperation, Held in Seoul, Korea on 20 November 2008

    Science.gov (United States)

    2009-02-01

    to East or Southeast Asia. If these routes were no longer cheap or safe, ships would use other routes, such as the Straits of Lombok and Makassar...34Chokepoints: Maritime Economic Concerns in Southeast Asia. "CNA Publications No. CRM 2796000700 and 2796000709/. (1996) See also, http...hormuz.robertstrausscenter.org/other_chokepoints 6 Kivlehan and Rosen, "The South China Sea: A Regional Assessment. CNA Publication No. CRM D0003145.A1 of March 2001

  5. Review: Margaret A. Morrison, Eric Haley, Kim Bartel Sheehan & Ronal E. Taylor (2002. Using Qualitative Research in Advertising: Strategies, Techniques, and Applications / Shay Sayre (2001. Qualitative Methods for Marketplace Research

    Directory of Open Access Journals (Sweden)

    Susanne Friese

    2004-01-01

    Full Text Available The review discusses two books, both covering very similar contents and addressing more or less the same audience. The book by SAYRE is about the use of qualitative method in marketplace research in general and is aimed at marketing students and practitioners; the book by MORRISON, HALEY, SHEEHAN and TAYLOR focuses more specifically on one area of mar­keting, namely advertising research. MORRISON et al. provide the more practical perspective, a fact that is also reflected in the writing style of the book. It is stimulating to read, even for readers fa­miliar with qualitative methods. It provides insights from the perspective of advertising agency plan­ners and demonstrates how qualitative methods are applied in a commercial context. SAYRE, in comparison, provides more details and builds her book around five theoretical perspectives. It is writ­ten by an academic for a largely academic audi­ence, containing all the basics that one needs to know when embarking on a qualitative research project. It differs from other qualitative method books in that the various steps along the way are illustrated by examples from the field of marketing. The book will, therefore, resonate well with mar­ket­ing students. Nonetheless, both books can be recommended as text books for qualitative method courses in marketing—SAYRE's book for market­ing students in general, and MORRISON et al.'s book for students specializing in the field of adver­tising. When used in a course where students conduct a small scale research project on their own, both books need to be supplemented by further readings or teacher input. Specifically, the sections on qualitative data analysis are too thin in MORRISON et al. and too broad in SAYRE in order to be useful to students without further explanation and training. Nonetheless, the two books are the best I have seen so far when it comes to selecting a book to be used in a qualitative method course for marketing students. URN: urn:nbn:de:0114-fqs0401258

  6. Cathy J. Schlund-Vials, Linda Trinh Võ and K. Scott Wong,eds., Keywords for Asian American StudiesCrystal Parikh and Daniel Y. Kim, eds. The Cambridge Companion to Asian American Literature

    OpenAIRE

    Kimak, Izabella

    2016-01-01

    Two recent publications, Keywords for Asian American Studies and The Cambridge Companion to Asian American Literature, both published in 2015 by New York University Press and Cambridge University Press, respectively, constitute scholarly attempts at encompassing the most crucial developments that have taken place within the field of Asian American studies in the last few decades. These new publications follow in the footsteps of such seminal titles as Elaine H. Kim’s 1982 Asian American Liter...

  7. Oral vaccination with LcrV from Yersinia pestis KIM delivered by live attenuated Salmonella enterica serovar Typhimurium elicits a protective immune response against challenge with Yersinia pseudotuberculosis and Yersinia enterocolitica.

    Science.gov (United States)

    Branger, Christine G; Torres-Escobar, Ascención; Sun, Wei; Perry, Robert; Fetherston, Jacqueline; Roland, Kenneth L; Curtiss, Roy

    2009-08-27

    The use of live recombinant attenuated Salmonella vaccines (RASV) synthesizing Yersinia proteins is a promising approach for controlling infection by Yersinia species. In this study, we constructed attenuated Salmonella strains which synthesize a truncated form of LcrV, LcrV196 and evaluated the immune response and protective efficacy elicited by these strains in mice against two other major species of Yersinia: Yersinia pseudotuberculosis and Yersinia enterocolitica. Surprisingly, we found that the RASV strain alone was sufficient to afford nearly full protection against challenge with Y. pseudotuberculosis, indicating the likelihood that Salmonella produces immunogenic cross-protective antigens. In contrast, lcrV196 expression was required for protection against challenge with Y. enterocolitica strain 8081, but was not sufficient to achieve significant protection against challenge with Y. enterocolitica strain WA, which expressed a divergent form of lcrV. Nevertheless, we are encouraged by these findings to continue pursuing our long-term goal of developing a single vaccine to protect against all three human pathogenic species of Yersinia.

  8. Postmodern Dönemde Kimliğin Belirleyicisi Olarak Tüketim [Tüketilmiş Kimlikler] / The Consumption as a Determination of Identity in The Postmodern Era [Consumed Identities

    Directory of Open Access Journals (Sweden)

    Nihal Yavuz

    2015-12-01

     [Tüketilmiş Kimlikler] Öz Teknolojik gelişmeye bağlı olarak artan üretim ve ürün çeşitliliği, insanların günlük ihtiyaçlarını karşılamanın ötesinde onları tüketime yönlendirmeye başlamıştır. Tüketimde hedonist anlayışın ön plana çıktığı bu dönemde insanlar, tüketim vasıtasıyla yeni yaşam tarzları ve üretilebilir hatta yeniden üretilebilir kimlikler oluşturmuştur. Günümüz postmodern toplumunda kimlik ve tüketim ilişkisi, üzerinde durulması gereken bir konudur. Bu araştırma, postmodern dönemdeki çoğul ve parçalanmış kimliklerin oluşumunda tüketim alışkanlıklarının etkisini açıklamaya çalışmaktadır. İnsan davranışlarına yön vermeye başlayan tüketim, artık bir kimlik göstergesi biçimini almıştır. Tüketim, bireylerin kimlik oluşumunda etkili olurken, tüketim alışkanlıklarında sembolik değerlerin ön plana çıktığı görülmektedir. Her şeyin hızla tüketildiği günümüz dünyasında artık kimlikler de tüketilir hale gelmiştir.

  9. Anmeldelse af Ulrik Rammeskow Bang-Pedersen, Lasse Højlund Christensen, Kim Sommer Jensen, Christian Jul Madsen & Andreas Kærsgaard Mylin: Rekonstruktion – teori og praksis (2011)

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2011-01-01

    Artiklen anmelder det nævnte værk, som i detaljer behandler lov nr. 718 af 25. juni 2010, der indførte regler i konkursloven, som muliggør rekonstruktion af både fysiske og juridiske personer med henblik på virksomhedsoverdragelse og tvangsakkord, og således at skyldneren ikke selv kan standse re...

  10. The Impact of Korean Local Elections. Strategic Forum, Number 49, October 1995

    National Research Council Canada - National Science Library

    Drennan, William

    1995-01-01

    ...) political landscape. The elections produced a new generation of political leaders while setting the stage for one final clash of the titans of the old guard, the "three Kims"--Kim Young Sam, Kim Dae Jung and Kim Jong Pil...

  11. Enhancement-Mode AlGaN/GaN High Electron Mobility Transistors Using a Nano-Channel Array Structure

    International Nuclear Information System (INIS)

    Liu Sheng-Hou; Cai Yong; Zeng Chun-Hong; Shi Wen-Hua; Zhang Bao-Shun; Gong Ru-Min; Wang Jin-Yan; Wen, Cheng P.; Feng Zhi-Hong; Wang Jing-Jing; Yin Jia-Yun; Qin Hua

    2011-01-01

    A nano-channel array (NCA) structure is applied to realize enhancement-mode (E-mode) AlGaN/GaN high-electron mobility transistors (HEMTs). The fabricated NCA-HEMT, consisting of 1000 channels connected in parallel with a channel width of 64 nm, shows a threshold voltage of 0.15 V and a subthreshold slope of 78 mV/dec, compared to −3.92 V and 99 mV/dec for a conventional HEMT (C-HEMT), respectively Both the NCA-HEMT and C-HEMT show similar gate leakage current, indicating no significant degradation in gate leakage characteristics for the NCA-HEMT. The surrounding-field effect and relieved polarization contribute to the very large positive threshold voltage shift, while the work function difference makes it positive. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  12. Fabrication and characterization of V-gate AlGaN/GaN high-electron-mobility transistors

    International Nuclear Information System (INIS)

    Zhang Kai; Cao Meng-Yi; Chen Yong-He; Yang Li-Yuan; Wang Chong; Ma Xiao-Hua; Hao Yue

    2013-01-01

    V-gate GaN high-electron-mobility transistors (HEMTs) are fabricated and investigated systematically. A V-shaped recess geometry is obtained using an improved Si 3 N 4 recess etching technology. Compared with standard HEMTs, the fabricated V-gate HEMTs exhibit a 17% higher peak extrinsic transconductance due to a narrowed gate foot. Moreover, both the gate leakage and current dispersion are dramatically suppressed simultaneously, although a slight degradation of frequency response is observed. Based on a two-dimensional electric field simulation using Silvaco “ATLAS” for both standard HEMTs and V-gate HEMTs, the relaxation in peak electric field at the gate edge is identified as the predominant factor leading to the superior performance of V-gate HEMTs. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Advanced Amplifier Based Receiver Front Ends for Submillimeter-Wave-Sounders Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop high electron mobility transistor (HEMT) amplifier based heterodyne radiometers to provide high sensitivity at millimeter and submillimeter wavelengths with...

  14. Growth and characterization of AlGaN/GaN/AlGaN double-heterojunction high-electron-mobility transistors on 100-mm Si(111) using ammonia-molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Ravikiran, L.; Radhakrishnan, K., E-mail: ERADHA@ntu.edu.sg; Yiding, Lin; Ng, G. I. [NOVITAS-Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Dharmarasu, N.; Agrawal, M.; Arulkumaran, S.; Vicknesh, S. [Temasek Laboratories@NTU, Nanyang Technological University, Singapore 637553 (Singapore)

    2015-01-14

    To improve the confinement of two-dimensional electron gas (2DEG) in AlGaN/GaN high electron mobility transistor (HEMT) heterostructures, AlGaN/GaN/AlGaN double heterojunction HEMT (DH-HEMT) heterostructures were grown using ammonia-MBE on 100-mm Si substrate. Prior to the growth, single heterojunction HEMT (SH-HEMT) and DH-HEMT heterostructures were simulated using Poisson-Schrödinger equations. From simulations, an AlGaN buffer with “Al” mole fraction of 10% in the DH-HEMT was identified to result in both higher 2DEG concentration (∼10{sup 13 }cm{sup −2}) and improved 2DEG confinement in the channel. Hence, this composition was considered for the growth of the buffer in the DH-HEMT heterostructure. Hall measurements showed a room temperature 2DEG mobility of 1510 cm{sup 2}/V.s and a sheet carrier concentration (n{sub s}) of 0.97 × 10{sup 13 }cm{sup −2} for the DH-HEMT structure, while they are 1310 cm{sup 2}/V.s and 1.09 × 10{sup 13 }cm{sup −2}, respectively, for the SH-HEMT. Capacitance-voltage measurements confirmed the improvement in the confinement of 2DEG in the DH-HEMT heterostructure, which helped in the enhancement of its room temperature mobility. DH-HEMT showed 3 times higher buffer break-down voltage compared to SH-HEMT, while both devices showed almost similar drain current density. Small signal RF measurements on the DH-HEMT showed a unity current-gain cut-off frequency (f{sub T}) and maximum oscillation frequency (f{sub max}) of 22 and 25 GHz, respectively. Thus, overall, DH-HEMT heterostructure was found to be advantageous due to its higher buffer break-down voltages compared to SH-HEMT heterostructure.

  15. PHEMT as a circuit element for high impedance nanopower amplifiers for ultra-low temperatures application

    Science.gov (United States)

    Korolev, A. M.; Shulga, V. M.; Gritsenko, I. A.; Sheshin, G. A.

    2015-04-01

    In this work, high electron mobility transistor (HEMT) was studied as a circuit element for amplifiers operating at temperatures of the order of 10-100 mK. To characterize the HEMT, the relative parameters are proposed to be used. HEMT characteristics were measured at a temperature of 50 mK for the first time. It follows from the reported studies that the power consumption of high-impedance HEMT-based amplifiers can be reduced down to hundreds of nanowatt or even lower.

  16. Microwave Integrated Circuit Amplifier Designs Submitted to Qorvo for Fabrication with 0.09-micron High Electron Mobility Transistors (HEMTs) using 2-mil Gallium Nitride (GaN) on Silicon Carbide (SiC)

    Science.gov (United States)

    2016-03-01

    monolithic microwave integrated circuits (MMICs) are essential for compact hand-held satellite communications systems that provide instant, secure data...of approximately 30 to 45 GHz, monolithic microwave integrated circuits (MMICs) are essential for compact hand- held satellite communications (SATCOM...efforts focused on developing efficient high-power amplifiers for SATCOM applications , while current efforts are focused on modeling efforts

  17. The growth of a low defect InAs HEMT structure on Si by using an AlGaSb buffer layer containing InSb quantum dots for dislocation termination.

    Science.gov (United States)

    Ko, Kwang-Man; Seo, Jung-Han; Kim, Dong-Eun; Lee, Sang-Tae; Noh, Young-Kyun; Kim, Moon-Deock; Oh, Jae-Eung

    2009-06-03

    It is found that the surface migration and nucleation behaviors of InSb quantum dots on AlSb/Si substrates, formed by molecular beam epitaxy in Stranski-Krastanov (SK) growth mode, are dependent on the substrate temperature. At relatively high temperatures above 430 degrees C, quantum dots are migrated and preferentially assembled onto the surface steps of high defect AlSb layers grown on Si substrates, while they are uniformly distributed on the surface at lower temperatures below 400 degrees C. It is also found that quantum dots located on the defect sites lead to effective termination of the propagation of micro-twin-induced structural defects into overlying layers, resulting in the low defect material grown on a largely mismatched substrate. The resulting 1.0 microm thick Al(x)Ga(1-x)Sb (x = 0.8) layer grown on the silicon substrate shows atomically flat (0.2 nm AFM mean roughness) surface and high crystal quality, represented by a narrow full width at half-maximum of 300 arc s in the x-ray rocking curve. The room-temperature electron mobility of higher than 16 000 cm(2) V(-1) s(-1) in InAs/AlGaSb FETs on the Si substrate is obtained with a relatively thin buffer layer, when a low defect density ( approximately 10(6) cm(-2)) AlGaSb buffer layer is obtained by the proposed method.

  18. Narrowing of band gap at source/drain contact scheme of nanoscale InAs-nMOS

    Science.gov (United States)

    Mohamed, A. H.; Oxland, R.; Aldegunde, M.; Hepplestone, S. P.; Sushko, P. V.; Kalna, K.

    2018-04-01

    A multi-scale simulation study of Ni/InAs nano-scale contact aimed for the sub-14 nm technology is carried out to understand material and transport properties at a metal-semiconductor interface. The deposited Ni metal contact on an 11 nm thick InAs channel forms an 8.5 nm thick InAs leaving a 2.5 nm thick InAs channel on a p-type doped (1 × 1016 cm-3) AlAs0.47Sb0.53 buffer. The density functional theory (DFT) calculations reveal a band gap narrowing in the InAs at the metal-semiconductor interface. The one-dimensional (1D) self-consistent Poisson-Schrödinger transport simulations using real-space material parameters extracted from the DFT calculations at the metal-semiconductor interface, exhibiting band gap narrowing, give a specific sheet resistance of Rsh = 90.9 Ω/sq which is in a good agreement with an experimental value of 97 Ω/sq.

  19. Electrical characteristics of AlGaN-GaN high electron mobility transistors and AlGaN Schottky diodes irradiated with protons

    Science.gov (United States)

    Sin, Yongkun; Presser, Nathan; Foran, Brendan; LaLumondiere, Stephen; Lotshaw, William; Moss, Steven C.

    2014-03-01

    AlGaN-GaN high electron mobility transistors (HEMTs) are most suitable for commercial and military applications requiring high voltage, high power, and high efficiency operation. In recent years, leading AlGaN HEMT manufacturers have reported encouraging reliability of these devices, but their long-term reliability especially in the space environment still remains a major concern. In addition, degradation mechanisms in AlGaN HEMT devices are still not well understood, and a large number of traps and defects present both in the bulk and at the surface lead to undesirable characteristics. Study of reliability and radiation effects of AlGaN-GaN HEMTs is therefore necessary before GaN HEMT technology is successfully employed in satellite communication systems. For the present study, we investigated electrical characteristics of AlGaN-GaN HEMTs and AlGaN Schottky diodes irradiated with protons. We studied two types of MOCVD-grown AlGaN HEMTs on semi-insulating SiC substrates (HEMT-1 and HEMT-2) as well as MOCVD-grown Al0.27Ga 0.73N Schottky diodes on conducting SiC substrates. Our HEMT-1 structure consisted of a GaN cap, AlGaN/AlN barrier, and 2 μm GaN buffer layers. Our HEMT-2 structure consisting of undoped AlGaN barrier and GaN buffer layers grown on an AlN nucleation layer showed a charge sheet density of ~1013/cm2 and a Hall mobility of ~1500 cm2 /V.sec. Our HEMT-1 devices had a Pt-Au Schottky gate length of 0.2 μm, a total gate width of 200-400 μm periphery, and SiNx passivation. Electrical characteristics of AlGaN-GaN HEMTs and AlGaN Schottky diodes were compared before and after they were proton irradiated with different energies and fluences. Current-mode deep level transient spectroscopy (DLTS) and capacitance-mode DLTS were employed to study pre-proton irradiation trap characteristics in the AlGaN-GaN HEMTs and AlGaN Schottky diodes, respectively. Focused ion beam (FIB) was employed to prepare both cross-sectional and plan view TEM samples for defect

  20. An enzymatic biosensor based on three-dimensional ZnO nanotetrapods spatial net modified AlGaAs/GaAs high electron mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yu [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology, Beijing 100083 (China); Bioengineering Program, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Zhang, Xiaohui; Yan, Xiaoqin; Liao, Qingliang; Wang, Zengze; Zhang, Yue, E-mail: yuezhang@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology, Beijing 100083 (China)

    2014-11-24

    We designed and constructed three dimensional (3D) zinc oxide Nanotetrapods (T-ZnOs) modified AlGaAs/GaAs high electron mobility transistors (HEMTs) for enzymatic uric acid (UA) detection. The chemical vapor deposition synthesized T-ZnOs was distributed on the gate areas of HEMTs in order to immobilize uricase and improve the sensitivity of the HEMTs. Combining with the high efficiency of enzyme immobilization by T-ZnOs and high sensitivity from HEMT, the as-constructed uricase/T-ZnOs/HEMTs biosensor showed fast response towards UA at ∼1 s, wide linear range from 0.2 nM to 0.2 mM and the low detect limit at 0.2 nM. The results point out an avenue to design electronic device as miniaturized lab-on-chip device for high sensitive and specific in biomedical and clinical diagnosis applications.

  1. Trap states in AlGaN channel high-electron-mobility transistors

    International Nuclear Information System (INIS)

    Zhao, ShengLei; Zhang, Kai; Ha, Wei; Chen, YongHe; Zhang, Peng; Zhang, JinCheng; Hao, Yue; Ma, XiaoHua

    2013-01-01

    Frequency dependent capacitance and conductance measurements were performed to analyze the trap states in the AlGaN channel high-electron-mobility transistors (HEMTs). The trap state density in the AlGaN channel HEMTs decreases from 1.26 × 10 13  cm −2 eV −1 at the energy of 0.33 eV to 4.35 × 10 11  cm −2 eV −1 at 0.40 eV. Compared with GaN channel HEMTs, the trap states in the AlGaN channel HEMTs have deeper energy levels. The trap with deeper energy levels in the AlGaN channel HEMTs is another reason for the reduction of the reverse gate leakage current besides the higher Schottky barrier height

  2. Investigation of high sensitivity radio-frequency readout circuit based on AlGaN/GaN high electron mobility transistor

    International Nuclear Information System (INIS)

    Zhang Xiao-Yu; Sun Jian-Dong; Li Xin-Xing; Zhou Yu; Lü Li; Qin Hua; Tan Ren-Bing

    2015-01-01

    An AlGaN/GaN high electron mobility transistor (HEMT) device is prepared by using a semiconductor nanofabrication process. A reflective radio-frequency (RF) readout circuit is designed and the HEMT device is assembled in an RF circuit through a coplanar waveguide transmission line. A gate capacitor of the HEMT and a surface-mounted inductor on the transmission line are formed to generate LC resonance. By tuning the gate voltage V g , the variations of gate capacitance and conductance of the HEMT are reflected sensitively from the resonance frequency and the magnitude of the RF reflection signal. The aim of the designed RF readout setup is to develop a highly sensitive HEMT-based detector. (paper)

  3. Trap states in AlGaN channel high-electron-mobility transistors

    Science.gov (United States)

    Zhao, ShengLei; Zhang, Kai; Ha, Wei; Chen, YongHe; Zhang, Peng; Zhang, JinCheng; Ma, XiaoHua; Hao, Yue

    2013-11-01

    Frequency dependent capacitance and conductance measurements were performed to analyze the trap states in the AlGaN channel high-electron-mobility transistors (HEMTs). The trap state density in the AlGaN channel HEMTs decreases from 1.26 × 1013 cm-2eV-1 at the energy of 0.33 eV to 4.35 × 1011 cm-2eV-1 at 0.40 eV. Compared with GaN channel HEMTs, the trap states in the AlGaN channel HEMTs have deeper energy levels. The trap with deeper energy levels in the AlGaN channel HEMTs is another reason for the reduction of the reverse gate leakage current besides the higher Schottky barrier height.

  4. Investigation of high sensitivity radio-frequency readout circuit based on AlGaN/GaN high electron mobility transistor

    Science.gov (United States)

    Zhang, Xiao-Yu; Tan, Ren-Bing; Sun, Jian-Dong; Li, Xin-Xing; Zhou, Yu; Lü, Li; Qin, Hua

    2015-10-01

    An AlGaN/GaN high electron mobility transistor (HEMT) device is prepared by using a semiconductor nanofabrication process. A reflective radio-frequency (RF) readout circuit is designed and the HEMT device is assembled in an RF circuit through a coplanar waveguide transmission line. A gate capacitor of the HEMT and a surface-mounted inductor on the transmission line are formed to generate LC resonance. By tuning the gate voltage Vg, the variations of gate capacitance and conductance of the HEMT are reflected sensitively from the resonance frequency and the magnitude of the RF reflection signal. The aim of the designed RF readout setup is to develop a highly sensitive HEMT-based detector. Project supported by the National Natural Science Foundation of China (Grant No. 61107093), the Suzhou Science and Technology Project, China (Grant No. ZXG2012024), and the Youth Innovation Promotion Association, Chinese Academy of Sciences (Grant No. 2012243).

  5. Electrothermal evaluation of thick GaN epitaxial layers and AlGaN/GaN high-electron-mobility transistors on large-area engineered substrates

    Science.gov (United States)

    Anderson, Travis J.; Koehler, Andrew D.; Tadjer, Marko J.; Hite, Jennifer K.; Nath, Anindya; Mahadik, Nadeemullah A.; Aktas, Ozgur; Odnoblyudov, Vladimir; Basceri, Cem; Hobart, Karl D.; Kub, Francis J.

    2017-12-01

    AlGaN/GaN high-electron-mobility transistor (HEMT) device layers were grown by metal organic chemical vapor deposition (MOCVD) on commercial engineered QST™ substrates to demonstrate a path to scalable, cost-effective foundry processing while supporting the thick epitaxial layers required for power HEMT structures. HEMT structures on 150 mm Si substrates were also evaluated. The HEMTs on engineered substrates exhibited material quality, DC performance, and forward blocking performance superior to those of the HEMT on Si. GaN device layers up to 15 µm were demonstrated with a wafer bow of 1 µm, representing the thickest films grown on 150-mm-diameter substrates with low bow to date.

  6. Informatics Observed [and] Agenda: A Tool for Agenda Setting Research [and] Telos Language Partner: Multimedia Language Learning, Authoring and Customisation [and] Towards a Consumer Perspective on Information Behaviour Research [and] The Digital Library as Access Management Facilitator [and] Knowledge and Information Management (KIM'21) [and] Perspectives of ICT in Professional Development and Education.

    Science.gov (United States)

    Cawkell, Tony; Kok, Yeong Haur; Goh, Angela; Holaday, Duncan; Hoffstaedter, Petra; Kohn, Kurt; Rowley, Jennifer; van Halm, Johan; Pye, Jo

    1999-01-01

    The following collection of articles reprinted from "CD ROM and Online Review" include "a new way of learning." Discuses research and development funding in educational technology and recommends to offer vast sums to investigate the best way of teaching a particular topic, and through that to fund the use of computers as an incidental part of the…

  7. General characteristics of causes of urban flood damage and flood forecasting/warning system in Seoul, Korea Young-Il Moon1, 2, Jong-Suk Kim1, 2 1 Department of Civil Engineering, University of Seoul, Seoul 130-743, South Korea 2 Urban Flood Research Inst

    Science.gov (United States)

    Moon, Young-Il; Kim, Jong-Suk

    2015-04-01

    Due to rapid urbanization and climate change, the frequency of concentrated heavy rainfall has increased, causing urban floods that result in casualties and property damage. As a consequence of natural disasters that occur annually, the cost of damage in Korea is estimated to be over two billion US dollars per year. As interest in natural disasters increase, demands for a safe national territory and efficient emergency plans are on the rise. In addition to this, as a part of the measures to cope with the increase of inland flood damage, it is necessary to build a systematic city flood prevention system that uses technology to quantify flood risk as well as flood forecast based on both rivers and inland water bodies. Despite the investment and efforts to prevent landside flood damage, research and studies of landside-river combined hydro-system is at its initial stage in Korea. Therefore, the purpose of this research introduces the causes of flood damage in Seoul and shows a flood forecasting and warning system in urban streams of Seoul. This urban flood forecasting and warning system conducts prediction on flash rain or short-term rainfall by using radar and satellite information and performs prompt and accurate prediction on the inland flooded area and also supports synthetic decision-making for prevention through real-time monitoring. Although we cannot prevent damage from typhoons or localized heavy rain, we can minimize that damage with accurate and timely forecast and a prevention system. To this end, we developed a flood forecasting and warning system, so in case of an emergency there is enough time for evacuation and disaster control. Keywords: urban flooding, flood risk, inland-river system, Korea Acknowledgments This research was supported by a grant (13AWMP-B066744-01) from Advanced Water Management Research Program (AWMP) funded by Ministry of Land, Infrastructure and Transport of Korean government.

  8. 1942-1943 Arası Dönemde Kıbrıs Türk Kimliğinin İlk Kurumsallaşma Hareketleri Early Movements of Institutionalizing the Cypriot Turkish Identity Between 1942 and 1943

    Directory of Open Access Journals (Sweden)

    Sibel AKGÜN

    2012-09-01

    Full Text Available Cyprus has been occupying the agenda of international relationssince the mid-20th Century, and it still remains among the unsolvedproblems in the world. The island has a political history that is definedby contrasting interests and political demands in the EasternMediterranean. Apart from global and local balances, the main problem in Cyprus is the idea of nationalism that emerged mostly in 1878 and has crystallized in the process of ethnic differentiation between the two major ethnic and religious communities living in the island. This idea has been consolidated by the policies pursued by the British colonial administration and by the influences of local elites; and thus two conflicting identities emerged. How these two identities, whose objectives and methods are different from one another, firstly emerged in a serious manner is of importance in political-cultural-sociocultural terms. The factors that triggered these processes and helped them get institutionalized constitute an important issue that needs to be addressed as much as their origins. It was the 1940s when those organizations firstly formed, which would serve as social carriers in the fields of media and political and professional organization. This process, which was triggered by international developments, will be addressed by examining each of the organizations such as KATAK and Halkın Sesi. While addressing this process, whose institutional foundations were Enosis, British colonial administration policies and Cypriot Turkish nationalism; the developments of the time will also be taken into consideration. The main subject of the study, on the other hand, will be the dynamics and development of these foundations in the 1940s in terms of organization for the Cypriot Turkish community. Kıbrıs, 20. yüzyılın ortasından itibaren uluslararası ilişkileringündeminde olup, günümüzün çözümlenmemiş sorunlarından biriniteşkil etmektedir. Ada, Doğu Akdeniz’de birbirine karşıt çıkarların vesiyasi isteklerin belirlediği siyasi tarihi ile hareketli bir geçmişe sahiptir.Küresel ve bölgesel dengelerin dışında, Kıbrıs’ta asıl sorun, büyükölçüde 1878 yılından başlayan ve adanın iki büyük etnik ve dinsel halkıarasında, etnik farklılaşma süreci ile belirginleşmiş olan milliyetçilikolgusudur. Bu olguya, İngiliz sömürge yönetiminin izlediği politikalar veyerel seçkin denilen aydınlar ve elitlerin etkisi de eklenince birbirinekarşıt, çatışan bir kimlik ikiliği ortaya çıkmıştır. Amaçları ve yönelimlerifarklı olan bu kimliklerin, oluşma süreci dışında politik - kültürel -sosyo ekonomik olarak ciddi anlamda ilk ortaya çıkma süreçleriönemlidir. Bu süreci tetikleyen ve kurumsallaşmasına neden olanfaktörler, ilk oluşmaya başlama dönemleri kadar önemli ve üzerindedurulması gereken bir konudur.Kıbrıs Türk halkı içinde basın yayın, siyasi ve meslekiörgütlenme alanlarında birer sosyal taşıyıcı olan yapılarınoluşturulması 1940’lı yıllara denk gelmektedir. Uluslararasıgelişmelerin etkisi ile başlayan bu süreç, tek tek KATAK, Halkın Sesigibi sosyal taşıyıcı yapıların incelenmesi ile ele alınacaktır. Kurumsaltemelinde Enosis, İngiliz sömürge yönetimi politikaları ve Kıbrıs Türkmilliyetçiliği olan bu süreç ele alınırken, dönemin gelişmeleri de gözönünde bulundurularak bir çözümleme yapılacaktır. Ayrı ayrı elealınabilecek olan bu temellerin, Kıbrıs Türk halkı için kurumsallaşmaanlamında 1940’lı yıllardaki dinamiği ve gelişimi ise çalışmanın anakonusu olacaktır.

  9. Reklamların ve Cinsiyet Kimliği Rolünün Tüketicilerin Satın Alma Davranışları Üzerindeki Etkisi = The Effect of Advertisements and Gender Identity Role on Consumer Buying Behavior

    Directory of Open Access Journals (Sweden)

    Mehmet İsmail YAĞCI

    2010-01-01

    Full Text Available Gender is a segmentation criterion which has been used for a long time especially for the analyses of consumer behavior in traditional marketing. However an obligation has aroused to digress the traditional patterns in order to understand consumer behavior in our rapidly changing world. At this point, “gender identity role” concept which is frequently encountered in the literature reminded may help researchers in understanding complex consumer buying behavior. In this study, consumer’s gender identity’s impact on their response to advertisements and whether their socio-economic status levels’ effect their gender identities or not have been analyzed and some significant relations have been found.

  10. Práctica de enseñanza de las matemáticas en educación general básica :análisis de caso en segundo año en el Centro Educativo Fiscal Bilingüe Salomón Kim.

    OpenAIRE

    Reyes Cruz, Soraya Dolores

    2016-01-01

    When performing the respective exploration on preliminary investigations related to teaching practices on Basic Education in Ecuador, no written evidence was found on the subject. It shows the importance of developing a strategic plan of practices in teaching sciences, with a teaching method and a proposed lesson plans containing some practices in the student environment at this level. This research case, intends to diagnose, describe and analyze the teaching pract...

  11. Tracking Theory Building and Use Trends in Selected LIS Journals: More Research is Needed. A review of: Kim, Sung‐Jin, and Dong Y. Jeong. “An Analysis of the Development and Use of Theory in Library and Information Science Research Articles.” Library & Information Science Research 28.4 (Sept. 2006: 548‐62.

    Directory of Open Access Journals (Sweden)

    Carol Perryman

    2007-09-01

    Full Text Available Objective ‐ The authors measure theory incidents occurring in four LIS journals between 1984‐2003 in order to examine their number and quality and to analyze them by topic. A third objective, only identified later in the text of the study, was to compare theory development and use between Korean and international journals. Research questions asked include whether LIS has its own theoretical base as a discipline, and what characteristics the theoretical framework has.Design – Bibliometric study.Setting – Journal issues selected from four LIS journals for the time span from 1984 ‐ 2003.Subjects – Two international journals, Journal of the American Society for Information Science and Technology (JASIST and Library and Information Science Research (LISR were selected based on their high ranking in the Social Sciences Citation Index (SSCI impact factors. Two Korean journals, Journal of the Korean Society for Information Management (JKSIM and Journal of the Korean Society for Library and Information Science (JKSLIS were selected.Methods ‐ After having determined a definition of theory, and identifying different levels of theory, the authors set up rules for the identification of theory incidents, which are defined as “events in which the author contributed to the development or the use of theory in his/her own paper” (550. Content analysis of 1661 research articles was performed to measure theory incidents according to working definitions. Interrater reliability was ensured by conducting independent coding for “subfield classification, identification of theory incidents, and quality measurement” (555,using a sample of 199 articles (random selection not specified, achieving 94‐97% interrater reliability. Incidents, once identified, were evaluated for quality using Dubin’s “efficiency of law” criteria, involving measures of relatedness, directionality, co‐variation, rate of change, and “profundity,” defined as the depth to which theory is incorporated into the research study.Main Results ‐ 21.79% (n=362 of the articles contained theory incidents that were analyzed and evaluated. Trend measurement indicated an overall increase, although a slight decrease was shown in the year range 1993‐2003. International journals accounted for 61.33% of theory incidents, compared to 38.67% for the Korean journals. T‐testing showed that differences in means between Korean and international journals were not statistically significant. Topical theory areas were ranked by frequency. The top five areas were shown to be nearly identical between Korean and international journals. ANOVA was performed with significant results in the difference between efficiency ratings. Conclusion – The authors find that the overall proportion of theory incidents including both theory development and use increased through the 20‐year time span examined, and that LIS has established its own theoretical framework based upon the frequency of incidents.

  12. Osman Turan'ın Siyasetçi Kimliği ve Yassıada'da Yargılanması (1954-1961 Political Identity Of Osman Turan And His Trial In Yassıada (1954-1961

    Directory of Open Access Journals (Sweden)

    Zehra ARSLAN

    2013-09-01

    Full Text Available Osman Turan entered politics as the parliamentarian of Trabzonfrom Democrat Party after the elections held on 2nd of May 1954. Hecontinued his service until 1960 coup d’etat. During his service, heexpressed that he did not approve some of the enforcements ofDemocrat Party, to which he was a member, such as making Kırşehir adistrict, arrangements at universities and cautions against theopposition during the speeches he gave in Grand National Assembly ofTurkey and party group. In the post-1960 coup d’etat period (27th ofMay, a Grand Jury was constituted which led the accusations madetowards DP members after the coup d’etat and some laws grantingextraordinary authorities were enacted. Osman Turan was not presentin the Assembly due to health problems which prevented him fromrating either favorably or unfavorably. His name was mentioned withthose of oppositions since he sometimes contradicted Menderes. Therewere even rumors that he would be expelled. However, Osman Turanpreferred to keep his battle within DP. He was arrested after coup d’etatand he gave his testimony on 30th of June in 1960 for the first time. Hewas put on trial within the scope of articles no. 141 and 146 fromTurkish Penal Code in the bylaw prepared by prosecution. The onlyaccusation made in the name of Osman Turan in the bylaw was theclaim that he received a certain amount of foreign currency. As a resultof evidence he provided in addition to his defense and investigation, itwas proven that the claims against him were unreal. He experiencedsome health problems during his arrest which lasted for 16.5 months.He could not attend all of the trials for he was being treated in thehospital located in garrison. Osman Turan was one of the 45 defendantswho were arrested due to violation of constitutional law on 15th ofSeptember 1961 and acquitted later on. 2 Mayıs 1954 seçimleri ile Demokrat Parti Trabzon Milletvekili olarak aktif siyasete atılan Osman Turan, 27 Mayıs 1960 Darbesi'ne kadar bu görevini sürdürmüştür. Milletvekilliği süresince mensubu bulunduğu Demokrat Partinin Kırşehir'in ilçe haline getirilmesi, üniversitelerde yapılan düzenlemeler, muhalefete karşı alınan tedbirler vb. uygulamalarını tasvip etmediğini TBMM ve parti grubunda yaptığı konuşmalarda dile getirmiştir. 27 Mayıs Darbesi sonrası DP mensuplarına yönelik suçlamaların başını çeken Tahkikat Encümeni oluşturulması ve bu encümene olağanüstü yetkiler veren kanunların çıkartılması sırasında da Osman Turan, sağlık problemleri nedeniyle mecliste bulunamamış dolayısı ile bu kanunlara lehte veya aleyhte oy vermemiştir. Menderes'le zaman zaman ters düştüğü için parti içerisinde adı, muhaliflerle birlikte anılmış hatta ihraç edileceği yönünde söylentiler ortaya atılmıştı. Fakat mücadelesini DP içerisinde sürdürme yolunu seçen Osman Turan, darbe ile birlikte tutuklanmış, ilk ifadesini de 30 Haziran 1960 tarihinde vermiştir. İddia makamı tarafından hazırlanan kararnamede, Türk Ceza Kanununun 141 ve 146ncı maddeleri kapsamında yargılanmıştır. Kararnamede Osman Turan'ın adının geçtiği tek suçlama ise bir miktar döviz aldığı iddiası olmuştur. Savunmasına ek olarak sunduğu deliller ve yapılan soruşturmalar sonucunda aleyhinde yapılan suçlamaların gerçek dışı olduğu kanıtlanmıştır. Toplam 16,5 ay tutukluluk döneminde sağlık problemleri yaşamış ve garnizondaki hastanede tedavi altına alındığı için duruşmaların tümüne iştirak edememiştir. Osman Turan, 15 Eylül 1961 tarihinde anayasayı ihlal suçundan tutuklu bulunup beraatına karar verilen 45 sanık arasında yer almıştır.

  13. X-ray crystal structures of the pheromone-binding domains of two quorum-hindered transcription factors, YenR of Yersinia enterocolitica and CepR2 of Burkholderia cenocepacia: KIM et al.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngchang [Midwest Center for Structural Genomics, Biosciences, Argonne National Laboratory, Argonne Illinois 60439; Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne Illinois 60439; Chhor, Gekleng [Midwest Center for Structural Genomics, Biosciences, Argonne National Laboratory, Argonne Illinois 60439; Tsai, Ching-Sung [Department of Microbiology, Cornell University, Ithaca New York 14853; Fox, Gabriel [Department of Microbiology, Cornell University, Ithaca New York 14853; Chen, Chia-Sui [Department of Microbiology, Cornell University, Ithaca New York 14853; Winans, Nathan J. [Department of Microbiology, Cornell University, Ithaca New York 14853; Jedrzejczak, Robert [Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne Illinois 60439; Joachimiak, Andrzej [Midwest Center for Structural Genomics, Biosciences, Argonne National Laboratory, Argonne Illinois 60439; Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne Illinois 60439; Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois 60637; Winans, Stephen C. [Department of Microbiology, Cornell University, Ithaca New York 14853

    2017-07-24

    The ability of LuxR-type proteins to regulate transcription is controlled by bacterial pheromones, N-acylhomoserine lactones (AHLs). Most LuxR-family proteins require their cognate AHLs for activity, and some of them require AHLs for folding and stability, and for protease-resistance. However, a few members of this family are able to fold, dimerize, bind DNA, and regulate transcription in the absence of AHLs; moreover, these proteins are antagonized by their cognate AHLs. One such protein is YenR of Yersinia enterocolitica, which is antagonized by N-3-oxohexanoyl-l-homoserine lactone (OHHL). This pheromone is produced by the OHHL synthase, a product of the adjacent yenI gene. Another example is CepR2 of Burkholderia cenocepacia, which is antagonized by N-octanoyl-l-homoserine lactone (OHL), whose synthesis is directed by the cepI gene of the same bacterium. Here, we describe the high-resolution crystal structures of the AHL binding domains of YenR and CepR2. YenR was crystallized in the presence and absence of OHHL. While this ligand does not cause large scale changes in the YenR structure, it does alter the orientation of several highly conserved YenR residues within and near the pheromone-binding pocket, which in turn caused a significant movement of a surface-exposed loop.

  14. In situ rumen degradability characteristics of rice straw, soybean ...

    African Journals Online (AJOL)

    In situ rumen degradability characteristics of rice straw, soybean curd residue and peppermint (Mentha piperita) in Hanwoo steer (Bos Taurus coreanae). Byong Tae Jeon, KyoungHoon Kim, Sung Jin Kim, Na Yeon Kim, Jae Hyun Park, Dong Hyun Kim, Mi Rae Oh, Sang Ho Moon ...

  15. Inhibitory effect of emodin on raw 264.7 activated with double ...

    African Journals Online (AJOL)

    Inhibitory effect of emodin on raw 264.7 activated with double stranded RNA analogue poly I:C. Young-Jin Kim, Ji Young Lee, Hyun-Ju Kim, Do-Hoon Kim, Tae Hee Lee, Mi Suk Kang, You-Kyung Choi, Hye Lim Lee, Jaieun Kim, Hyo-Jin An, Wansu Park ...

  16. Enhanced two dimensional electron gas transport characteristics in Al2O3/AlInN/GaN metal-oxide-semiconductor high-electron-mobility transistors on Si substrate

    Science.gov (United States)

    Freedsman, J. J.; Watanabe, A.; Urayama, Y.; Egawa, T.

    2015-09-01

    The authors report on Al2O3/Al0.85In0.15N/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistor (MOS-HEMT) on Si fabricated by using atomic layer deposited Al2O3 as gate insulator and passivation layer. The MOS-HEMT with the gate length of 2 μm exhibits excellent direct-current (dc) characteristics with a drain current maximum of 1270 mA/mm at a gate bias of 3 V and an off-state breakdown voltage of 180 V for a gate-drain spacing of 4 μm. Also, the 1 μm-gate MOS-HEMT shows good radio-frequency (rf) response such as current gain and maximum oscillation cut-off frequencies of 10 and 34 GHz, respectively. The capacitance-voltage characteristics at 1 MHz revealed significant increase in two-dimensional electron gas (2DEG) density for the MOS-HEMT compared to conventional Schottky barrier HEMTs. Analyses using drain-source conductivity measurements showed improvements in 2DEG transport characteristics for the MOS-HEMT. The enhancements in dc and rf performances of the Al2O3/Al0.85In0.15N/GaN MOS-HEMT are attributed to the improvements in 2DEG characteristics.

  17. Enhanced two dimensional electron gas transport characteristics in Al2O3/AlInN/GaN metal-oxide-semiconductor high-electron-mobility transistors on Si substrate

    International Nuclear Information System (INIS)

    Freedsman, J. J.; Watanabe, A.; Urayama, Y.; Egawa, T.

    2015-01-01

    The authors report on Al 2 O 3 /Al 0.85 In 0.15 N/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistor (MOS-HEMT) on Si fabricated by using atomic layer deposited Al 2 O 3 as gate insulator and passivation layer. The MOS-HEMT with the gate length of 2 μm exhibits excellent direct-current (dc) characteristics with a drain current maximum of 1270 mA/mm at a gate bias of 3 V and an off-state breakdown voltage of 180 V for a gate-drain spacing of 4 μm. Also, the 1 μm-gate MOS-HEMT shows good radio-frequency (rf) response such as current gain and maximum oscillation cut-off frequencies of 10 and 34 GHz, respectively. The capacitance-voltage characteristics at 1 MHz revealed significant increase in two-dimensional electron gas (2DEG) density for the MOS-HEMT compared to conventional Schottky barrier HEMTs. Analyses using drain-source conductivity measurements showed improvements in 2DEG transport characteristics for the MOS-HEMT. The enhancements in dc and rf performances of the Al 2 O 3 /Al 0.85 In 0.15 N/GaN MOS-HEMT are attributed to the improvements in 2DEG characteristics

  18. Physical and electrical characteristics of AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors with rare earth Er2O3 as a gate dielectric

    International Nuclear Information System (INIS)

    Lin, Ray-Ming; Chu, Fu-Chuan; Das, Atanu; Liao, Sheng-Yu; Chou, Shu-Tsun; Chang, Liann-Be

    2013-01-01

    In this study, the rare earth erbium oxide (Er 2 O 3 ) was deposited using an electron beam onto an AlGaN/GaN heterostructure to fabricate metal-oxide-semiconductor high-electron-mobility transistors (MOS–HEMTs) that exhibited device performance superior to that of a conventional HEMT. Under similar bias conditions, the gate leakage currents of these MOS–HEMT devices were four orders of magnitude lower than those of conventional Schottky gate HEMTs. The measured sub-threshold swing (SS) and the effective trap state density (N t ) of the MOS–HEMT were 125 mV/decade and 4.3 × 10 12 cm −2 , respectively. The dielectric constant of the Er 2 O 3 layer in this study was 14, as determined through capacitance–voltage measurements. In addition, the gate–source reverse breakdown voltage increased from –166 V for the conventional HEMT to –196 V for the Er 2 O 3 MOS–HEMT. - Highlights: ► GaN/AlGaN/Er 2 O 3 metal-oxide semiconductor high electron mobility transistor ► Physical and electrical characteristics are presented. ► Electron beam evaporated Er 2 O 3 with excellent surface roughness ► Device exhibits reduced gate leakage current and improved I ON /I OFF ratio

  19. Experimental study on vertical scaling of InAs-on-insulator metal-oxide-semiconductor field-effect transistors

    Science.gov (United States)

    Kim, SangHyeon; Yokoyama, Masafumi; Nakane, Ryosho; Ichikawa, Osamu; Osada, Takenori; Hata, Masahiko; Takenaka, Mitsuru; Takagi, Shinichi

    2014-06-01

    We have investigated effects of the vertical scaling on electrical properties in extremely thin-body InAs-on-insulator (-OI) metal-oxide-semiconductor field-effect transistors (MOSFETs). It is found that the body thickness (Tbody) scaling provides better short channel effect (SCE) control, whereas the Tbody scaling also causes the reduction of the mobility limited by channel thickness fluctuation (δTbody) scattering (μfluctuation). Also, in order to achieve better SCEs control, the thickness of InAs channel layer (Tchannel) scaling is more favorable than the thickness of MOS interface buffer layer (Tbuffer) scaling from a viewpoint of a balance between SCEs control and μfluctuation reduction. These results indicate necessity of quantum well channel structure in InAs-OI MOSFETs and these should be considered in future transistor design.

  20. Effect of interfacial layer on the crystal structure of InAs/AlAs{sub 0.16}Sb{sub 0.84}/AlSb quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y. M., E-mail: ymlin.ee97g@g2.nctu.edu.tw [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China); Chen, C. H. [Center for Nano Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China); Lee, C. P. [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China); Center for Nano Science and Technology, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China)

    2014-04-28

    Ion channeling technique using MeV C{sup 2+} ions and high resolution X-ray diffraction were used to study the crystal quality of an InAs/AlSb-based quantum wells. We found that the InAs quality has a strong dependence on the type of the interface used. With the addition of the InSb-like interface, the crystal quality of the InAs channel was greatly improved. The InAs lattice was fully strained and aligned with the lattice of the buffer layer without any lattice relaxation. On the other hand, if the interface was of the AlAs type, the lattice of the InAs quantum well was relaxed and the crystal quality was poor. This explains why a superior InAs quantum well with high electron mobility and good surface morphology can be achieved with the use of the InSb interface.

  1. Two-Dimensional Modeling of Aluminum Gallium Nitride/Gallium Nitride High Electron Mobility Transistor

    National Research Council Canada - National Science Library

    Holmes, Kenneth

    2002-01-01

    Gallium Nitride (GaN) High Electron Mobility Transistors (HEMT's) are microwave power devices that have the performance characteristics to improve the capabilities of current and future Navy radar and communication systems...

  2. Monolithically integrated AlN/GaN electronics for harsh environments, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Recently, resonant-tunneling-diode (RTD) based circuits employing monolithically-integrated RTD on high electron mobility (HEMT) structures have been developed in a...

  3. Characterising thermal resistances and capacitances of GaN high-electron-mobility transistors through dynamic electrothermal measurements

    DEFF Research Database (Denmark)

    Wei, Wei; Mikkelsen, Jan H.; Jensen, Ole Kiel

    2014-01-01

    This study presents a method to characterise thermal resistances and capacitances of GaN high-electron-mobility transistors (HEMTs) through dynamic electrothermal measurements. A measured relation between RF gain and the channel temperature (Tc) is formed and used for indirect measurements...... method ensures that trapping effects have insignificant impact on the measurements of Tc responses, which makes this method suitable for GaN HEMT characterisation. The applicability of this method is demonstrated by characterising thermal resistances and capacitances of a CREE CGH40006P GaN HEMT....... of dynamic Tc responses. Thermal resistances and capacitances are characterised on the basis of measured Tc responses and power dissipation (Pd) in HEMTs. The proposed method makes it possible to measure fast Tc responses and avoids the use of imaging and spectroscopy techniques. Additionally, the proposed...

  4. High-Power Electron Accelerators for Space (and other) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-23

    This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power high-electron mobility transistors (HEMT) testing, and Li-ion battery design. In summary, the authors have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). Finally, the authors are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

  5. Two-Dimensional Modeling of Aluminum Gallium Nitride/Gallium Nitride High Electron Mobility Transistor

    National Research Council Canada - National Science Library

    Holmes, Kenneth

    2002-01-01

    .... This thesis studies the effects of AIGaN/GaN HEMTs' polarization, piezoelectric (PZ) and spontaneous, properties utilizing the TM commercially available Silvaco Atlas software for modeling and simulation...

  6. A two-dimensional fully analytical model with polarization effect for off-state channel potential and electric field distributions of GaN-based field-plated high electron mobility transistor

    International Nuclear Information System (INIS)

    Mao Wei; She Wei-Bo; Zhang Chao; Zhang Jin-Cheng; Zhang Jin-Feng; Liu Hong-Xia; Yang Lin-An; Zhang Kai; Zhao Sheng-Lei; Chen Yong-He; Zheng Xue-Feng; Hao Yue; Yang Cui; Ma Xiao-Hua

    2014-01-01

    In this paper, we present a two-dimensional (2D) fully analytical model with consideration of polarization effect for the channel potential and electric field distributions of the gate field-plated high electron mobility transistor (FP-HEMT) on the basis of 2D Poisson's solution. The dependences of the channel potential and electric field distributions on drain bias, polarization charge density, FP structure parameters, AlGaN/GaN material parameters, etc. are investigated. A simple and convenient approach to designing high breakdown voltage FP-HEMTs is also proposed. The validity of this model is demonstrated by comparison with the numerical simulations with Silvaco—Atlas. The method in this paper can be extended to the development of other analytical models for different device structures, such as MIS-HEMTs, multiple-FP HETMs, slant-FP HEMTs, etc. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  7. Small-signal modeling with direct parameter extraction for impact ionization effect in high-electron-mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Guan, He; Lv, Hongliang; Guo, Hui, E-mail: hguan@stu.xidian.edu.cn; Zhang, Yuming [Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2015-11-21

    Impact ionization affects the radio-frequency (RF) behavior of high-electron-mobility transistors (HEMTs), which have narrow-bandgap semiconductor channels, and this necessitates complex parameter extraction procedures for HEMT modeling. In this paper, an enhanced small-signal equivalent circuit model is developed to investigate the impact ionization, and an improved method is presented in detail for direct extraction of intrinsic parameters using two-step measurements in low-frequency and high-frequency regimes. The practicability of the enhanced model and the proposed direct parameter extraction method are verified by comparing the simulated S-parameters with published experimental data from an InAs/AlSb HEMT operating over a wide frequency range. The results demonstrate that the enhanced model with optimal intrinsic parameter values that were obtained by the direct extraction approach can effectively characterize the effects of impact ionization on the RF performance of HEMTs.

  8. Trap state analysis in AlGaN/GaN/AlGaN double heterostructure high electron mobility transistors at high temperatures

    Science.gov (United States)

    Zhang, WeiHang; Xue, JunShuai; Zhang, Li; Zhang, Tao; Lin, ZhiYu; Zhang, JinCheng; Hao, Yue

    2017-06-01

    In this work, frequency-dependent capacitances and conductance measurements are adopted to investigate high temperature characteristics of trap states in AlGaN/GaN/AlGaN double heterostructure high electron mobility transistors (DH-HEMTs). It is found that fast and slow trap states are present in DH-HEMTs, while only fast traps exist in AlGaN/GaN single heterostructure (SH) HEMTs. In the former, the fast trap state density ranges from 4.6 × 1012 cm-2 eV-1 to 1.9 × 1013 cm-2 eV-1 located at an energy below the conduction band between 0.273 eV and 0.277 eV, and the slow deep trap state density decreases from 2.4 × 1013 cm-2 eV-1 to 8.7 × 1012 cm-2 eV-1 located at an energy ranging from 0.384 eV to 0.423 eV in DH-HEMTs with a 14 nm GaN channel layer. These active trap energy levels in DH-HEMTs become deeper as the thickness of the channel layer decreases. In addition, the active trap energy levels in SH- and DH-HEMTs gradually become deeper as the measurement temperature increases. Also, the change in amplitude of the active trap energy levels in DH-HEMTs is larger than that in SH-HEMTs, which indicates that DH is efficient in suppressing the reverse gate leakage current at high temperatures.

  9. Evaluation of AlGaN/GaN metal-oxide-semicondutor high-electron mobility transistors with plasma-enhanced atomic layer deposition HfO2/AlN date dielectric for RF power applications

    Science.gov (United States)

    Chiu, Yu Sheng; Luc, Quang Ho; Lin, Yueh Chin; Chien Huang, Jui; Dee, Chang Fu; Yeop Majlis, Burhanuddin; Chang, Edward Yi

    2017-09-01

    A plasma enhanced atomic layer deposition (PEALD) HfO2/AlN dielectric stack was used as the gate dielectric for AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) for high-frequency power device applications. The capacitance-voltage (C-V) curves of the HfO2/AlN/GaN MOS capacitor (MOSCAP) showed a small frequency dispersion along with a very small hysteresis (˜50 mV). Moreover, the interface trap density (D it) was calculated to be 2.7 × 1011 cm-2 V-1 s-1 at 150 °C. Using PEALD-AlN as the interfacial passivation layer (IPL), the drain current of the HfO2/AlN MOS-HEMTs increased by about 46% and the gate leakage current decreased by six orders of magnitude as compared with those of the conventional Schottky gate AlGaN/GaN HEMTs processed using the same epitaxial wafer. The 0.3-µm-gate-length HfO2/AlN/AlGaN/GaN MOS-HEMTs demonstrated a 2.88 W/mm output power, a 23 dB power gain, a 30.2% power-added efficiency at 2.4 GHz, and an improved device linearity as compared with the conventional AlGaN/GaN HEMTs. The third-order intercept point at the output (OIP3) of the MOS-HEMTs was 28.4 as compared with that of 26.5 for the conventional GaN HEMTs. Overall, the MOS-HEMTs with a HfO2/AlN gate stack showed good potential for high-linearity RF power device applications.

  10. Epitaxial ZnO gate dielectrics deposited by RF sputter for AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors

    Science.gov (United States)

    Yoon, Seonno; Lee, Seungmin; Kim, Hyun-Seop; Cha, Ho-Young; Lee, Hi-Deok; Oh, Jungwoo

    2018-01-01

    Radio frequency (RF)-sputtered ZnO gate dielectrics for AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) were investigated with varying O2/Ar ratios. The ZnO deposited with a low oxygen content of 4.5% showed a high dielectric constant and low interface trap density due to the compensation of oxygen vacancies during the sputtering process. The good capacitance-voltage characteristics of ZnO-on-AlGaN/GaN capacitors resulted from the high crystallinity of oxide at the interface, as investigated by x-ray diffraction and high-resolution transmission electron microscopy. The MOS-HEMTs demonstrated comparable output electrical characteristics with conventional Ni/Au HEMTs but a lower gate leakage current. At a gate voltage of -20 V, the typical gate leakage current for a MOS-HEMT with a gate length of 6 μm and width of 100 μm was found to be as low as 8.2 × 10-7 mA mm-1, which was three orders lower than that of the Ni/Au Schottky gate HEMT. The reduction of the gate leakage current improved the on/off current ratio by three orders of magnitude. These results indicate that RF-sputtered ZnO with a low O2/Ar ratio is a good gate dielectric for high-performance AlGaN/GaN MOS-HEMTs.

  11. Investigation of trap states in high Al content AlGaN/GaN high electron mobility transistors by frequency dependent capacitance and conductance analysis

    Directory of Open Access Journals (Sweden)

    Jie-Jie Zhu

    2014-03-01

    Full Text Available Trap states in Al0.55Ga0.45N/GaN Schottky-gate high-electron-mobility transistors (S-HEMTs and Al2O3/Al0.55Ga0.45N/GaN metal-oxide-semiconductor HEMTs (MOS-HEMTs were investigated with conductance method in this paper. Surface states with time constant of (0.09–0.12 μs were found in S-HEMTs, and electron tunneling rather than emission was deemed to be the dominant de-trapping mechanism due to the high electric field in high Al content barrier. The density of surface states evaluated in S-HEMTs was (1.02–4.67×1013 eV−1·cm−2. Al2O3 gate insulator slightly reduced the surface states, but introduced low density of new traps with time constant of (0.65–1.29 μs into MOS-HEMTs.

  12. Influence of 60Co gamma radiation on fluorine plasma treated enhancement-mode high-electron-mobility transistor

    Science.gov (United States)

    Quan, Si; Hao, Yue; Ma, Xiao-Hua; Yu, Hui-You

    2011-05-01

    AlGaN/GaN depletion-mode high-electron-mobility transistor (D-HEMT) and fluorine (F) plasma treated enhancement-mode high-electron-mobility transistor (E-HEMT) are exposed to 60Co gamma radiation with a dose of 1.6 Mrad (Si). No degradation is observed in the performance of D-HEMT. However, the maximum transconductance of E-HEMT is increased after radiation. The 2DEG density and the mobility are calculated from the results of capacitance-voltage measurement. The electron mobility decreases after fluorine plasma treatment and recovers after radiation. Conductance measurements in a frequency range from 10 kHz to 1 MHz are used to characterize the trapping effects in the devices. A new type of trap is observed in the F plasma treated E-HEMT compared with the D-HEMT, but the density of the trap decreases by radiation. Fitting of Gp/ω data yields the trap densities DT = (1 - 3) × 1012 cm-2 · eV-1 and DT = (0.2 - 0.8) × 1012 cm-2 · eV-1 before and after radiation, respectively. The time constant is 0.5 ms-6 ms. With F plasma treatment, the trap is introduced by etch damage and degrades the electronic mobility. After 60Co gamma radiation, the etch damage decreases and the electron mobility is improved. The gamma radiation can recover the etch damage caused by F plasma treatment.

  13. Investigation of trap states in high Al content AlGaN/GaN high electron mobility transistors by frequency dependent capacitance and conductance analysis

    Science.gov (United States)

    Zhu, Jie-Jie; Ma, Xiao-Hua; Hou, Bin; Chen, Wei-Wei; Hao, Yue

    2014-03-01

    Trap states in Al0.55Ga0.45N/GaN Schottky-gate high-electron-mobility transistors (S-HEMTs) and Al2O3/Al0.55Ga0.45N/GaN metal-oxide-semiconductor HEMTs (MOS-HEMTs) were investigated with conductance method in this paper. Surface states with time constant of (0.09-0.12) μs were found in S-HEMTs, and electron tunneling rather than emission was deemed to be the dominant de-trapping mechanism due to the high electric field in high Al content barrier. The density of surface states evaluated in S-HEMTs was (1.02-4.67)×1013 eV-1.cm-2. Al2O3 gate insulator slightly reduced the surface states, but introduced low density of new traps with time constant of (0.65-1.29) μs into MOS-HEMTs.

  14. Control of short-channel effects in InAlN/GaN high-electron mobility transistors using graded AlGaN buffer

    Science.gov (United States)

    Han, Tiecheng; Zhao, Hongdong; Peng, Xiaocan; Li, Yuhai

    2018-04-01

    A graded AlGaN buffer is designed to realize the p-type buffer by inducing polarization-doping holes. Based on the two-dimensional device simulator, the effect of the graded AlGaN buffer on the direct-current (DC) and radio-frequency (RF) performance of short-gate InAlN/GaN high-electron mobility transistors (HEMTs) are investigated, theoretically. Compared to standard HEMT, an enhancement of electron confinement and a good control of short-channel effect (SCEs) are demonstrated in the graded AlGaN buffer HEMT. Accordingly, the pinched-off behavior and the ability of gate modulation are significantly improved. And, no serious SCEs are observed in the graded AlGaN buffer HEMT with an aspect ratio (LG/tch) of about 6.7, much lower than that of the standard HEMT (LG/tch = 13). In addition, for a 70-nm gate length, a peak current gain cutoff frequency (fT) of 171 GHz and power gain cutoff frequency (fmax) of 191 GHz are obtained in the grade buffer HEMT, which are higher than those of the standard one with the same gate length.

  15. Pyongyangi leedi Macbeth tõmbab niite Põhja-Koreas / Yuriko Koike

    Index Scriptorium Estoniae

    Koike, Yuriko

    2010-01-01

    Põhja-Korea liidri Kim Jong-il'i õest Kim Kyong-hui'st. Autori, Jaapani endise kaitseministri väitel on hakatud uskuma, et Kim Jong-il võib igal hetkel määrata just Kim Kyong-hui üleminekuaja valitsejaks, kes peab korraldama tema surma järel kolmanda põlvkonna Kimi võimuletuleku, kuid Kim Kyong-hui võib ise ihata saada Kim Jong-ili mantlipärijaks

  16. Teratogenicity and brain aromatase-induction of monosodium ...

    African Journals Online (AJOL)

    Teratogenicity and brain aromatase-induction of monosodium glutamate in estrogen-responsive mosaic transgenic zebra fish Danio rerio. Tamer Said Abdelkader, Chang Seo-Na, Kim Tae-Hyun, Song Juha, Kim Dongso, Jae-Hak Park ...

  17. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... Imai M S Ippolitov M Ishihara B V Jacak W Y Jang J Jia B M Johnson S C Johnson K S Joo S Kametani J H Kang M Kann S S Kapoor S Kelly B Khachaturov A Khanzadeev J Kikuchi D J Kim H J Kim S Y Kim Y G Kim W W Kinnison E Kistenev A Kiyomichi C Klein-Boesing S Klinksiek L Kochenda D Kochetkov V Kochetkov ...

  18. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... J Jia B M Johnson S C Johnson K S Joo S Kametani J H Kang M Kann S S Kapoor S Kelly B Khachaturov A Khanzadeev J Kikuchi D J Kim H J Kim S Y Kim Y G Kim W W Kinnison E Kistenev A Kiyomichi C Klein-Boesing S Klinksiek L Kochenda V Kochetkov D Koehler T Kohama D Kotchetkov A Kozlov P J Kroon K Kurita ...

  19. Processing of nanocrystalline diamond thin films for thermal management of wide-bandgap semiconductor power electronics

    International Nuclear Information System (INIS)

    Govindaraju, N.; Singh, R.N.

    2011-01-01

    Highlights: → Studied effect of nanocrystalline diamond (NCD) deposition on device metallization. → Deposited NCD on to top of High Electron Mobility Transistors (HEMTs) and Si devices. → Temperatures below 290 deg. C for Si devices and 320 deg. C for HEMTs prevent metal damage. → Development of novel NCD-based thermal management for power electronics feasible. - Abstract: High current densities in wide-bandgap semiconductor electronics operating at high power levels results in significant self-heating of devices, which necessitates the development thermal management technologies to effectively dissipate the generated heat. This paper lays the foundation for the development of such technology by ascertaining process conditions for depositing nanocrystalline diamond (NCD) on AlGaN/GaN High Electron Mobility Transistors (HEMTs) with no visible damage to device metallization. NCD deposition is carried out on Si and GaN HEMTs with Au/Ni metallization. Raman spectroscopy, optical and scanning electron microscopy are used to evaluate the quality of the deposited NCD films. Si device metallization is used as a test bed for developing process conditions for NCD deposition on AlGaN/GaN HEMTs. Results indicate that no visible damage occurs to the device metallization for deposition conditions below 290 deg. C for Si devices and below 320 deg. C for the AlGaN/GaN HEMTs. Possible mechanisms for metallization damage above the deposition temperature are enumerated. Electrical testing of the AlGaN/GaN HEMTs indicates that it is indeed possible to deposit NCD on GaN-based devices with no significant degradation in device performance.

  20. Enhanced two dimensional electron gas transport characteristics in Al{sub 2}O{sub 3}/AlInN/GaN metal-oxide-semiconductor high-electron-mobility transistors on Si substrate

    Energy Technology Data Exchange (ETDEWEB)

    Freedsman, J. J., E-mail: freedy54@gmail.com; Watanabe, A.; Urayama, Y. [Research Center for Nano-Devices and Advanced Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466 8555 (Japan); Egawa, T., E-mail: egawa.takashi@nitech.ac.jp [Research Center for Nano-Devices and Advanced Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466 8555 (Japan); Innovation Center for Multi-Business of Nitride Semiconductors, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466 8555 (Japan)

    2015-09-07

    The authors report on Al{sub 2}O{sub 3}/Al{sub 0.85}In{sub 0.15}N/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistor (MOS-HEMT) on Si fabricated by using atomic layer deposited Al{sub 2}O{sub 3} as gate insulator and passivation layer. The MOS-HEMT with the gate length of 2 μm exhibits excellent direct-current (dc) characteristics with a drain current maximum of 1270 mA/mm at a gate bias of 3 V and an off-state breakdown voltage of 180 V for a gate-drain spacing of 4 μm. Also, the 1 μm-gate MOS-HEMT shows good radio-frequency (rf) response such as current gain and maximum oscillation cut-off frequencies of 10 and 34 GHz, respectively. The capacitance-voltage characteristics at 1 MHz revealed significant increase in two-dimensional electron gas (2DEG) density for the MOS-HEMT compared to conventional Schottky barrier HEMTs. Analyses using drain-source conductivity measurements showed improvements in 2DEG transport characteristics for the MOS-HEMT. The enhancements in dc and rf performances of the Al{sub 2}O{sub 3}/Al{sub 0.85}In{sub 0.15}N/GaN MOS-HEMT are attributed to the improvements in 2DEG characteristics.

  1. Physical and electrical characteristics of AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors with rare earth Er{sub 2}O{sub 3} as a gate dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Ray-Ming, E-mail: rmlin@mail.cgu.edu.tw; Chu, Fu-Chuan; Das, Atanu; Liao, Sheng-Yu; Chou, Shu-Tsun; Chang, Liann-Be

    2013-10-01

    In this study, the rare earth erbium oxide (Er{sub 2}O{sub 3}) was deposited using an electron beam onto an AlGaN/GaN heterostructure to fabricate metal-oxide-semiconductor high-electron-mobility transistors (MOS–HEMTs) that exhibited device performance superior to that of a conventional HEMT. Under similar bias conditions, the gate leakage currents of these MOS–HEMT devices were four orders of magnitude lower than those of conventional Schottky gate HEMTs. The measured sub-threshold swing (SS) and the effective trap state density (N{sub t}) of the MOS–HEMT were 125 mV/decade and 4.3 × 10{sup 12} cm{sup −2}, respectively. The dielectric constant of the Er{sub 2}O{sub 3} layer in this study was 14, as determined through capacitance–voltage measurements. In addition, the gate–source reverse breakdown voltage increased from –166 V for the conventional HEMT to –196 V for the Er{sub 2}O{sub 3} MOS–HEMT. - Highlights: ► GaN/AlGaN/Er{sub 2}O{sub 3} metal-oxide semiconductor high electron mobility transistor ► Physical and electrical characteristics are presented. ► Electron beam evaporated Er{sub 2}O{sub 3} with excellent surface roughness ► Device exhibits reduced gate leakage current and improved I{sub ON}/I{sub OFF} ratio.

  2. Computational identification of novel PR-1-type genes in Oryza sativa

    Indian Academy of Sciences (India)

    4465. Sarowar S., Kim Y. J., Kim E. N., Kim K. D., Hwang B. K., Is- lam R. and Shin J. S. 2005 Overexpression of a pepper basic pathogenesis-related protein 1 gene in tobacco plants enhances resistance to heavy metal and pathogen stresses.

  3. African Journal of Biotechnology - Vol 11, No 102 (2012)

    African Journals Online (AJOL)

    Development and characterization of nine polymorphic microsatellite markers in the seven-spotted lady beetle, Coccinella septempunctata (Coleoptera: Coccinellidae) · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Min Jee Kim, Ki-Hwan Kim, Kee Young Kim, ...

  4. Experimental analysis of current conduction through thermally ...

    Indian Academy of Sciences (India)

    A372, 529 (2008). [10] Kuan Yew Cheong, Jeong Hyun Moon, Hyeong Joon Kim, Wook Bahng and Nam-. Kyun Kim, J. Appl. Phys. 103, 084113 (2008). [11] Doo Seok Jeong and Cheol Seong Hwang, J. Appl. Phys. 98, 113701 (2005). [12] Kuan Yew Cheong, Jeong Hyun Moon, Hyeong Joon Kim, Wook Bahng and Nam-.

  5. Tubular kidney injury molecule-1 in protein-overload nephropathy

    NARCIS (Netherlands)

    van Timmeren, Mirjan M.; Bakker, Stephan J. L.; Vaidya, Vishal S.; Bailly, Veronique; Schuurs, Theo A.; Damman, Jeffrey; Stegeman, Coen A.; Bonventre, Joseph V.; van Goor, Harry

    Kim-1, a recently discovered membrane protein, is undetectable in normal kidneys but markedly induced in proximal tubules after ischemic and toxic injury. The function of Kim-1 is unclear, but it is implicated in damage/repair processes. The Kim-1 ectodomain is cleaved by metalloproteinases and

  6. Case Report

    African Journals Online (AJOL)

    2013 Jan;6(1):41-4. Case Report. AJNT. Abstract. Introduction: Risk of reactivation of Hepatitis B virus. (HBV) infection and other liver related complications continues to be a major ... serum envelope 'e' antigen (HBeAg) in patients already serologically .... Ahn HJ, Kim MS, Kim YS, Kim SI, Huh KH, Ju MK,. Ahn SH, Han KH.

  7. Supplementary data: Association of CTLA4, CD28 and ICOS gene ...

    Indian Academy of Sciences (India)

    with clinicopathologic characteristics of childhood IgA nephropathy in Korean population. Hak-Jae Kim, Joo-Ho Chung, Sungwook Kang, Su-Kang Kim, Byoung-Soo Cho, Sung-Do Kim and Won-Ho Hahn. J. Genet. 90, 151–155. Table 1. Primer sequence for the SNPs of CTLA4, CD28 and ICOS genes. Gene. SNP. Function.

  8. Pattern of change in histone 3 lysine 9 acetylation and histone ...

    Indian Academy of Sciences (India)

    2014-08-11

    Aug 11, 2014 ... Kim Y. S., Kim M. J., Koo T. H., Kim J. D., Koun S., Ham H. J. et al. 2012 Histone deacetylase is required for the activation of Wnt/β- catenin signaling crucial for heart valve formation in zebrafish embryos. Biochem. Biophys. Res. Commun. 423, 140–146. Kratz A., Arner E., Saito R., Kubosaki A., Kawai J., ...

  9. The impact of sugar and fatty acid on the bioactivity of N-fatty acyl-L ...

    Indian Academy of Sciences (India)

    SRIKANTH VUDHGIRI

    complex on colon cancer cells J. Food Biochem. 39. 238. 36. Kim D H, Jung E A, Sohng I S, Han J A, Kim T H and Han M J 1998 Intestinal bacterial metabolism of flavonoids and its relation to some biological activities. Arch. Pharm. Res. 21 17. 37. Kim D H 2002 Herbal medicines are activated by intesti- nal microflora Nat.

  10. Synthesis of silica nanosphere from homogeneous and ...

    Indian Academy of Sciences (India)

    WINTEC

    (Sadasivan et al 1998; Kim et al 2000; Kim and Kim. 2002; Park et al 2002). They also examined the influence of reaction methods (such as semi-batch reaction and batch reaction) on particle size and its distribution. A relatively slow rate of hydrolysis of TEOS occurred during the semi-batch process, which resulted in larger ...

  11. Journal of Genetics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Hak-Jae Kim Joo-Ho Chung Sungwook Kang Su-Kang Kim Byoung-Soo Cho Sung-Do Kim Won-Ho Hahn · More Details Fulltext PDF. pp 157-159 Research Note. Cystinuria AA (B): digenic inheritance with three mutations in two cystinuria genes · Zoran Gucev Nadica Ristoska-Bojkovska Katerina Popovska-Jankovic ...

  12. Aluminum gallium nitride (GaN)/GaN high electron mobility transistor-based sensors for glucose detection in exhaled breath condensate.

    Science.gov (United States)

    Chu, Byung Hwan; Kang, Byoung Sam; Hung, Sheng Chun; Chen, Ke Hung; Ren, Fan; Sciullo, Andrew; Gila, Brent P; Pearton, Stephen J

    2010-01-01

    Immobilized aluminum gallium nitride (AlGaN)/GaN high electron mobility transistors (HEMTs) have shown great potential in the areas of pH, chloride ion, and glucose detection in exhaled breath condensate (EBC). HEMT sensors can be integrated into a wireless data transmission system that allows for remote monitoring. This technology offers the possibility of using AlGaN/GaN HEMTs for extended investigations of airway pathology of detecting glucose in EBC without the need for clinical visits. HEMT structures, consisting of a 3-microm-thick undoped GaN buffer, 30-A-thick Al(0.3)Ga(0.7)N spacer, and 220-A-thick silicon-doped Al(0.3)Ga(0.7)N cap layer, were used for fabricating the HEMT sensors. The gate area of the pH, chloride ion, and glucose detection was immobilized with scandium oxide (Sc(2)O(3)), silver chloride (AgCl) thin film, and zinc oxide (ZnO) nanorods, respectively. The Sc(2)O(3)-gated sensor could detect the pH of solutions ranging from 3 to 10 with a resolution of approximately 0.1 pH. A chloride ion detection limit of 10(-8) M was achieved with a HEMT sensor immobilized with the AgCl thin film. The drain-source current of the ZnO nanorod-gated AlGaN/GaN HEMT sensor immobilized with glucose oxidase showed a rapid response of less than 5 seconds when the sensor was exposed to the target glucose in a buffer with a pH value of 7.4. The sensor could detect a wide range of concentrations from 0.5 nM to 125 microM. There is great promise for using HEMT-based sensors to enhance the detection sensitivity for glucose detection in EBC. Depending on the immobilized material, HEMT-based sensors can be used for sensing different materials. These electronic detection approaches with rapid response and good repeatability show potential for the investigation of airway pathology. The devices can also be integrated into a wireless data transmission system for remote monitoring applications. This sensor technology could use the exhaled breath condensate to measure the

  13. AlN passivation by plasma-enhanced atomic layer deposition for GaN-based power switches and power amplifiers

    Science.gov (United States)

    Chen, Kevin J.; Huang, Sen

    2013-07-01

    Developing an effective passivation technique for AlGaN/GaN high-electron-mobility transistors (HEMTs) is of primary importance to keep pace with the advancement of GaN-based high-voltage power switches and high-power amplifiers. In this work, effective passivation of AlGaN/GaN HEMT has been developed using a monocrystal-like AlN thin film grown by plasma-enhanced atomic layer deposition (ALD) (PEALD). Significant current collapse suppression and dynamic ON-resistance reduction are demonstrated in the PEALD-AlN-passivated AlGaN/GaN HEMTs, especially under high-drain-bias switching conditions. An output power density of 2.64 W mm-1 at 2 GHz is achieved on the PEALD-AlN-passivated GaN-on-Si HEMTs without the use of the field-plate. The physical mechanism of the PEALD-AlN passivation of AlGaN/GaN HEMTs is systematically investigated with high-frequency and quasi-static capacitance-voltage (C-V) characterizations, and a novel passivation scheme using polarization charges in passivation materials to compensate the slow-response interface trap states is proposed.

  14. AlN passivation by plasma-enhanced atomic layer deposition for GaN-based power switches and power amplifiers

    International Nuclear Information System (INIS)

    Chen, Kevin J; Huang, Sen

    2013-01-01

    Developing an effective passivation technique for AlGaN/GaN high-electron-mobility transistors (HEMTs) is of primary importance to keep pace with the advancement of GaN-based high-voltage power switches and high-power amplifiers. In this work, effective passivation of AlGaN/GaN HEMT has been developed using a monocrystal-like AlN thin film grown by plasma-enhanced atomic layer deposition (ALD) (PEALD). Significant current collapse suppression and dynamic ON-resistance reduction are demonstrated in the PEALD-AlN-passivated AlGaN/GaN HEMTs, especially under high-drain-bias switching conditions. An output power density of 2.64 W mm −1 at 2 GHz is achieved on the PEALD-AlN-passivated GaN-on-Si HEMTs without the use of the field-plate. The physical mechanism of the PEALD-AlN passivation of AlGaN/GaN HEMTs is systematically investigated with high-frequency and quasi-static capacitance–voltage (C–V) characterizations, and a novel passivation scheme using polarization charges in passivation materials to compensate the slow-response interface trap states is proposed. (invited paper)

  15. Temperature Effects on The Electrical Characteristics of In0.15Ga0.85As Pseudomorphic High-Electron-Mobility Transistors

    Directory of Open Access Journals (Sweden)

    BECHLAGHEM Fatima Zohra

    2017-10-01

    Full Text Available Nowadays, GaAs-based HEMTs and pseudomorphic HEMTs are speedily replacing conventional MESFET technology in military and commercial applications including, communication, radar and automotive technologies having need of high gain, and low noise figures especially at millimeter-wave frequencies. In this work, a short gate length pseudomorphic HEMT "p-HEMT" on GaAs substrate is treated. As temperature dependence study is a very important part of the complete characterization on active devices, the impact of temperature variation on the electrical properties of our 30nm short gate length pseudomorphic high-electron mobility In0.15Ga0.85As device is investigated. All our static DC device characteristics and RF response have been obtained using a device simulator that is Silvaco software to examine temperature impact on our device output current, transconductance and cutoff frequency. The 30nm gate pseudomorphic HEMT reported here exhibit superior DC and RF performances, Our results reveals a maximum drain-source current IDS up to 537.16 mA/mm, a peak extrinsic transconductance Gm of 345.4 mS/mm, a cutoff frequency Ft of 285.9 GHz, and a maximum frequency Fmax of 1580 GHz at room temperature.

  16. Electric Power Research in 1991

    International Nuclear Information System (INIS)

    1991-05-01

    This book of contents are a study of desalination by Kim, Young Bu, a study on efficiency test for nuclear power security by Jo, Sung Je; Ann, Nam Sung; Kim, Ho Gi, augmentation of EMS and RYU by Jung, Tae Hoe; Shin, Young Chuel, research on application for electric cars by Yu, Ann Gue, practical use oft robot for nuclear industry by Woo, He Gone; Shin, Hen Beom, a study on the characteristics of coolant structure in generator by Choi, Beng Hwan; Song, Young Chel; Kim, Jong Hark, and research of penetration rate of appliances by Park, Hong Ho; Kim, Beng Cheal; Kim, Dong Hwen.

  17. Depleting Glycine and Sarcosine in Prostate Cancer Cells as a New Treatment for Advanced Prostate Cancer

    Science.gov (United States)

    2015-04-01

    individual patients with few protocols established to determine whether the patient best fi ts for steroid injection, physical therapy , or surgical...10.1038/nm.2815 10. Hwang SY, Kim JY, Kim KW, Park MK, Moon Y, Kim WU, et al. IL-17 induces production of IL-6 and IL-8 in rheumatoid arthritis synovial...Park MK, Moon Y, Kim WU, Kim HY. IL-17 induces production of IL-6 and IL-8 in rheumatoid arthritis synovial fibroblasts via NF-kappaB- and PI3-kinase

  18. Glyphosate Vedotin for Treatment of Bone Metastatic Castration-Resistant Prostate Cancer

    Science.gov (United States)

    2015-07-01

    physical therapy , or surgical intervention. However, surgery is generally recommended for all symptomatic patients younger than 60 with a full...Park MK, Moon Y, Kim WU, et al. IL-17 induces production of IL-6 and IL-8 in rheumatoid arthritis synovial fibroblasts via NF-kappaB- and PI3-kinase...Hwang SY, Kim JY, Kim KW, Park MK, Moon Y, Kim WU, Kim HY. IL-17 induces production of IL-6 and IL-8 in rheumatoid arthritis synovial fibroblasts via

  19. Kidney Injury Molecule-1 Level is Associated with the Severity of Renal Interstitial Injury and Prognosis in Adult Henoch-Schönlein Purpura Nephritis.

    Science.gov (United States)

    Zhang, Yuanyuan; Li, Aiju; Wen, Jiliang; Zhen, Junhui; Hao, Qiufa; Zhang, Yidan; Hu, Zhao; Xiao, Xiaoyan

    2017-07-01

    Kidney injury molecule-1 (KIM-1) was identified the most highly upregulated protein in chronic kidney diseases and prolonged KIM-1 expression may be maladaptive. The present study was aimed to investigate urinary, renal and plasma KIM-1 levels and to analyze association between KIM-1 levels with clinical and pathological indexes in adult Henoch-Schönlein purpura (HSP) patients. Twenty healthy individuals, 20 HSP patients without nephritis and 35 HSP patients with nephritis were recruited. Urinary and plasma KIM-1 levels were determined by ELISA and Luminex, respectively. Renal KIM-1 expression was evaluated by immunohistochemistry. HSP patients with nephritis were characterized as elevated levels of urinary, renal and plasma KIM-1. Those with more severe tubular injury of renal biopsy tissues presented significantly higher urinary and renal KIM-1 levels compared to control and patients without nephritis. Urinary and renal levels of KIM-1 were positively correlated with blood urea nitrogen and proteinuria, while they were negatively correlated with eGFR at both baseline and after two years follow-up. Moreover, plasma KIM-1 levels were associated with blood urea nitrogen and proteinuria as well. Further univariate correlation analysis indicated urinary and renal KIM-1 levels were positively correlated with interstitial inflammation index and tubulointerstitial chronicity index. Only urinary KIM-1 levels were associated with interstitial inflammation index, tubulointerstitial chronicity index and extracapillary glomerular activity index, after logistic regression analysis. The area under the curve (AUC) for urinary KIM-1/Cr predicting progression of renal damage was significantly greater than the AUC for proteinuria. This finding suggests that measurement of urinary and renal KIM-1 level may be helpful to evaluate severity of renal pathological damage and prognosis in adult HSP patients with nephritis. Copyright © 2017 IMSS. Published by Elsevier Inc. All rights

  20. Breakdown mechanisms in AlGaN/GaN high electron mobility transistors with different GaN channel thickness values

    International Nuclear Information System (INIS)

    Ma Xiao-Hua; Zhang Ya-Man; Chen Wei-Wei; Wang Xin-Hua; Yuan Ting-Ting; Pang Lei; Liu Xin-Yu

    2015-01-01

    In this paper, the off-state breakdown characteristics of two different AlGaN/GaN high electron mobility transistors (HEMTs), featuring a 50-nm and a 150-nm GaN thick channel layer, respectively, are compared. The HEMT with a thick channel exhibits a little larger pinch-off drain current but significantly enhanced off-state breakdown voltage (BV off ). Device simulation indicates that thickening the channel increases the drain-induced barrier lowering (DIBL) but reduces the lateral electric field in the channel and buffer underneath the gate. The increase of BV off in the thick channel device is due to the reduction of the electric field. These results demonstrate that it is necessary to select an appropriate channel thickness to balance DIBL and BV off in AlGaN/GaN HEMTs. (paper)

  1. Ultrasensitive detection of Hg{sup 2+} using oligonucleotide-functionalized AlGaN/GaN high electron mobility transistor

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Junjie [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China); Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Li, Jiadong; Miao, Bin; Wu, Dongmin, E-mail: dmwu2008@sinano.ac.cn [i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215125 (China); Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Wang, Jine; Pei, Renjun, E-mail: rjpei2011@sinano.ac.cn [Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Wu, Zhengyan, E-mail: zywu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China)

    2014-08-25

    An oligonucleotide-functionalized ion sensitive AlGaN/GaN high electron mobility transistor (HEMT) was fabricated to detect trace amounts of Hg{sup 2+}. The advantages of ion sensitive AlGaN/GaN HEMT and highly specific binding interaction between Hg{sup 2+} and thymines were combined. The current response of this Hg{sup 2+} ultrasensitive transistor was characterized. The current increased due to the accumulation of Hg{sup 2+} ions on the surface by the highly specific thymine-Hg{sup 2+}-thymine recognition. The dynamic linear range for Hg{sup 2+} detection has been determined in the concentrations from 10{sup −14} to 10{sup −8} M and a detection limit below 10{sup −14} M level was estimated, which is the best result of AlGaN/GaN HEMT biosensors for Hg{sup 2+} detection till now.

  2. Ultrasensitive detection of Hg2+ using oligonucleotide-functionalized AlGaN/GaN high electron mobility transistor

    International Nuclear Information System (INIS)

    Cheng, Junjie; Li, Jiadong; Miao, Bin; Wu, Dongmin; Wang, Jine; Pei, Renjun; Wu, Zhengyan

    2014-01-01

    An oligonucleotide-functionalized ion sensitive AlGaN/GaN high electron mobility transistor (HEMT) was fabricated to detect trace amounts of Hg 2+ . The advantages of ion sensitive AlGaN/GaN HEMT and highly specific binding interaction between Hg 2+ and thymines were combined. The current response of this Hg 2+ ultrasensitive transistor was characterized. The current increased due to the accumulation of Hg 2+ ions on the surface by the highly specific thymine-Hg 2+ -thymine recognition. The dynamic linear range for Hg 2+ detection has been determined in the concentrations from 10 −14 to 10 −8 M and a detection limit below 10 −14 M level was estimated, which is the best result of AlGaN/GaN HEMT biosensors for Hg 2+ detection till now.

  3. High performance metamaterials-high electron mobility transistors integrated terahertz modulator.

    Science.gov (United States)

    Zhou, Zhen; Wang, Siqi; Yu, Yue; Chen, Yongli; Feng, Lishuang

    2017-07-24

    We demonstrate an electric control metamaterials-high electron mobility transistors (HEMTs) integrated terahertz (THz) modulator whose switching ability is developed by utilizing the symmetric quadruple-split-ring resonators (SRRs) metamaterial configuration and operating voltage is reduced by incorporating the HEMT elements. Meanwhile, the high switching speed of the HEMT implies that the THz modulator has a high potential in modulation speed. Under a reverse gate voltage of -4 V, the THz modulator exhibits a modulation depth of 80% at 0.86 THz and a phase shift of 0.67 rad (38.4°) at 0.77 THz, respectively. In addition, a modulation speed over 2.7 MHz is achieved and an improvement in the modulation speed of hundreds of MHz with optimum RC time constant is expected to achieve for the THz modulator.

  4. Improved linearity and reliability in GaN metal-oxide-semiconductor high-electron-mobility transistors using nanolaminate La2O3/SiO2 gate dielectric

    Science.gov (United States)

    Hsu, Ching-Hsiang; Shih, Wang-Cheng; Lin, Yueh-Chin; Hsu, Heng-Tung; Hsu, Hisang-Hua; Huang, Yu-Xiang; Lin, Tai-Wei; Wu, Chia-Hsun; Wu, Wen-Hao; Maa, Jer-Shen; Iwai, Hiroshi; Kakushima, Kuniyuki; Chang, Edward Yi

    2016-04-01

    Improved device performance to enable high-linearity power applications has been discussed in this study. We have compared the La2O3/SiO2 AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) with other La2O3-based (La2O3/HfO2, La2O3/CeO2 and single La2O3) MOS-HEMTs. It was found that forming lanthanum silicate films can not only improve the dielectric quality but also can improve the device characteristics. The improved gate insulation, reliability, and linearity of the 8 nm La2O3/SiO2 MOS-HEMT were demonstrated.

  5. Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

    International Nuclear Information System (INIS)

    So, Hongyun; Senesky, Debbie G.

    2016-01-01

    In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area

  6. Impact of barrier thickness on transistor performance in AlN/GaN high electron mobility transistors grown on free-standing GaN substrates

    International Nuclear Information System (INIS)

    Deen, David A.; Storm, David F.; Meyer, David J.; Bass, Robert; Binari, Steven C.; Gougousi, Theodosia; Evans, Keith R.

    2014-01-01

    A series of six ultrathin AlN/GaN heterostructures with varied AlN thicknesses from 1.5–6 nm have been grown by molecular beam epitaxy on free-standing hydride vapor phase epitaxy GaN substrates. High electron mobility transistors (HEMTs) were fabricated from the set in order to assess the impact of barrier thickness and homo-epitaxial growth on transistor performance. Room temperature Hall characteristics revealed mobility of 1700 cm 2 /V s and sheet resistance of 130 Ω/□ for a 3 nm thick barrier, ranking amongst the lowest room-temperature sheet resistance values reported for a polarization-doped single heterostructure in the III-Nitride family. DC and small signal HEMT electrical characteristics from submicron gate length HEMTs further elucidated the effect of the AlN barrier thickness on device performance.

  7. Impact of barrier thickness on transistor performance in AlN/GaN high electron mobility transistors grown on free-standing GaN substrates

    Energy Technology Data Exchange (ETDEWEB)

    Deen, David A., E-mail: david.deen@alumni.nd.edu; Storm, David F.; Meyer, David J.; Bass, Robert; Binari, Steven C. [Electronics Science and Technology Division, Naval Research Laboratory, Washington, DC 20375-5347 (United States); Gougousi, Theodosia [Physics Department, University of Maryland Baltimore County, Baltimore, Maryland 21250 (United States); Evans, Keith R. [Kyma Technologies, Raleigh, North Carolina 27617 (United States)

    2014-09-01

    A series of six ultrathin AlN/GaN heterostructures with varied AlN thicknesses from 1.5–6 nm have been grown by molecular beam epitaxy on free-standing hydride vapor phase epitaxy GaN substrates. High electron mobility transistors (HEMTs) were fabricated from the set in order to assess the impact of barrier thickness and homo-epitaxial growth on transistor performance. Room temperature Hall characteristics revealed mobility of 1700 cm{sup 2}/V s and sheet resistance of 130 Ω/□ for a 3 nm thick barrier, ranking amongst the lowest room-temperature sheet resistance values reported for a polarization-doped single heterostructure in the III-Nitride family. DC and small signal HEMT electrical characteristics from submicron gate length HEMTs further elucidated the effect of the AlN barrier thickness on device performance.

  8. Trap behaviours characterization of AlGaN/GaN high electron mobility transistors by room-temperature transient capacitance measurement

    Directory of Open Access Journals (Sweden)

    Bin Dong

    2016-09-01

    Full Text Available In this paper, the trap behaviours in AlGaN/GaN high electron mobility transistors (HEMTs are investigated using transient capacitance measurement. By measuring the transient gate capacitance variance (ΔC with different pulse height, the gate pulse induced trap behaviours in SiNX gate dielectric layer or at the SiNX/AlGaN interface is revealed. Based on the results, a model on electron traps in AlGaN/GaN HEMTs is proposed. The threshold voltage (Vth instability in AlGaN/GaN HEMTs is believed to be correlated with the presence of these traps in SiNX gate dielectric layer or at the SiNX/AlGaN interface. Furthermore, trap density before and after step-stress applied on drain electrode is quantitatively analyzed based on ΔC measurement.

  9. Improved linearity in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors with nonlinear polarization dielectric

    International Nuclear Information System (INIS)

    Gao, Tao; Xu, Ruimin; Kong, Yuechan; Zhou, Jianjun; Kong, Cen; Dong, Xun; Chen, Tangsheng

    2015-01-01

    We demonstrate highly improved linearity in a nonlinear ferroelectric of Pb(Zr 0.52 Ti 0.48 )-gated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT). Distinct double-hump feature in the transconductance-gate voltage (g m -V g ) curve is observed, yielding remarkable enhancement in gate voltage swing as compared to MIS-HEMT with conventional linear gate dielectric. By incorporating the ferroelectric polarization into a self-consistent calculation, it is disclosed that in addition to the common hump corresponding to the onset of electron accumulation, the second hump at high current level is originated from the nonlinear polar nature of ferroelectric, which enhances the gate capacitance by increasing equivalent dielectric constant nonlinearly. This work paves a way for design of high linearity GaN MIS-HEMT by exploiting the nonlinear properties of dielectric

  10. Trap behaviours characterization of AlGaN/GaN high electron mobility transistors by room-temperature transient capacitance measurement

    Science.gov (United States)

    Dong, Bin; Lin, Jie; Wang, Ning; Jiang, Ling-li; Liu, Zong-dai; Hu, Xiaoyan; Cheng, Kai; Yu, Hong-yu

    2016-09-01

    In this paper, the trap behaviours in AlGaN/GaN high electron mobility transistors (HEMTs) are investigated using transient capacitance measurement. By measuring the transient gate capacitance variance (Δ C ) with different pulse height, the gate pulse induced trap behaviours in SiNX gate dielectric layer or at the SiNX/AlGaN interface is revealed. Based on the results, a model on electron traps in AlGaN/GaN HEMTs is proposed. The threshold voltage (Vth) instability in AlGaN/GaN HEMTs is believed to be correlated with the presence of these traps in SiNX gate dielectric layer or at the SiNX/AlGaN interface. Furthermore, trap density before and after step-stress applied on drain electrode is quantitatively analyzed based on Δ C measurement.

  11. Improved linearity in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors with nonlinear polarization dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Tao [Fundamental Science on EHF Laboratory, University of Electronic Science and Technology of China (UESTC), Chengdu 611731 (China); Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing Electronic Devices Institute, Nanjing 210016 (China); Xu, Ruimin [Fundamental Science on EHF Laboratory, University of Electronic Science and Technology of China (UESTC), Chengdu 611731 (China); Kong, Yuechan, E-mail: kycfly@163.com; Zhou, Jianjun; Kong, Cen; Dong, Xun; Chen, Tangsheng [Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing Electronic Devices Institute, Nanjing 210016 (China)

    2015-06-15

    We demonstrate highly improved linearity in a nonlinear ferroelectric of Pb(Zr{sub 0.52}Ti{sub 0.48})-gated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT). Distinct double-hump feature in the transconductance-gate voltage (g{sub m}-V{sub g}) curve is observed, yielding remarkable enhancement in gate voltage swing as compared to MIS-HEMT with conventional linear gate dielectric. By incorporating the ferroelectric polarization into a self-consistent calculation, it is disclosed that in addition to the common hump corresponding to the onset of electron accumulation, the second hump at high current level is originated from the nonlinear polar nature of ferroelectric, which enhances the gate capacitance by increasing equivalent dielectric constant nonlinearly. This work paves a way for design of high linearity GaN MIS-HEMT by exploiting the nonlinear properties of dielectric.

  12. Improved linearity in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors with nonlinear polarization dielectric

    Science.gov (United States)

    Gao, Tao; Xu, Ruimin; Kong, Yuechan; Zhou, Jianjun; Kong, Cen; Dong, Xun; Chen, Tangsheng

    2015-06-01

    We demonstrate highly improved linearity in a nonlinear ferroelectric of Pb(Zr0.52Ti0.48)-gated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT). Distinct double-hump feature in the transconductance-gate voltage (gm-Vg) curve is observed, yielding remarkable enhancement in gate voltage swing as compared to MIS-HEMT with conventional linear gate dielectric. By incorporating the ferroelectric polarization into a self-consistent calculation, it is disclosed that in addition to the common hump corresponding to the onset of electron accumulation, the second hump at high current level is originated from the nonlinear polar nature of ferroelectric, which enhances the gate capacitance by increasing equivalent dielectric constant nonlinearly. This work paves a way for design of high linearity GaN MIS-HEMT by exploiting the nonlinear properties of dielectric.

  13. N-polar GaN/AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistor formed on sapphire substrate with minimal step bunching

    Science.gov (United States)

    Prasertsuk, Kiattiwut; Tanikawa, Tomoyuki; Kimura, Takeshi; Kuboya, Shigeyuki; Suemitsu, Tetsuya; Matsuoka, Takashi

    2018-01-01

    The metal-insulator-semiconductor (MIS) gate N-polar GaN/AlGaN/GaN high-electron-mobility transistor (HEMT) on a (0001) sapphire substrate, which can be expected to operate with lower on-resistance and more easily work on the pinch-off operation than an N-polar AlGaN/GaN HEMT, was fabricated. For suppressing the step bunching and hillocks peculiar in the N-polar growth, a sapphire substrate with an off-cut angle as small as 0.8° was introduced and an N-polar GaN/AlGaN/GaN HEMT without the step bunching was firstly obtained by optimizing the growth conditions. The previously reported anisotropy of transconductance related to the step was eliminated. The pinch-off operation was also realized. These results indicate that this device is promising.

  14. Design and characterisation of high electron mobility transistors for use in a monolithic GaAs X-ray imaging sensor

    International Nuclear Information System (INIS)

    Boardman, D.A.; Sellin, P.J.

    2001-01-01

    A new design of monolithic GaAs pixel detector is proposed for medical and synchrotron applications. In this device a semi-insulating GaAs wafer will be used as both the detector element and the substrate for the integrated charge readout matrix. The charge readout matrix consists of High Electron Mobility Transistors (HEMTs), which are grown epitaxially onto the GaAs substrate. Experimental characterisation of HEMTs has been carried out and their suitability for the proposed imaging device is assessed. Temperature measurements on initial devices showed the threshold voltage to be stable from room temperature down to -15 degree sign C. HEMT designs with lower leakage current that operate in enhancement mode have been fabricated and modelled using the Silvaco simulation package. These optimised devices have been fabricated using a gate recess, and exhibit enhancement mode operation and significantly reduced gate leakage currents

  15. Efficient AlGaN/GaN Linear and Digital-Switch-Mode Power Amplifiers for Operation at 2GHz

    Science.gov (United States)

    Maroldt, Stephan; Wiegner, Dirk; Vitanov, Stanislav; Palankovski, Vassil; Quay, Rüdiger; Ambacher, Oliver

    This work addresses the enormous efficiency and linearity potential of optimized AlGaN/GaN high-electron mobility transistors (HEMT) in conventional Doherty linear base-station amplifiers at 2.7GHz. Supported by physical device simulation, the work further elaborates on the use of AlGaN/GaN HEMTs in high-speed current-switch-mode class-D (CMCD)/class-S MMICs for data rates of up to 8Gbit/s equivalent to 2GHz RF-operation. The device needs for switch-mode operation are derived and verified by MMIC results in class-S and class-D operation. To the authors' knowledge, this is the first time 2GHz-equivalent digital-switch-mode RF-operation is demonstrated with GaN HEMTs with high efficiency.

  16. Influence of 60Co gamma radiation on fluorine plasma treated enhancement-mode high-electron-mobility transistor

    International Nuclear Information System (INIS)

    Quan Si; Hao Yue; Ma Xiao-Hua; Yu Hui-You

    2011-01-01

    AlGaN/GaN depletion-mode high-electron-mobility transistor (D-HEMT) and fluorine (F) plasma treated enhancement-mode high-electron-mobility transistor (E-HEMT) are exposed to 60 Co gamma radiation with a dose of 1.6 Mrad (Si). No degradation is observed in the performance of D-HEMT. However, the maximum transconductance of E-HEMT is increased after radiation. The 2DEG density and the mobility are calculated from the results of capacitance-voltage measurement. The electron mobility decreases after fluorine plasma treatment and recovers after radiation. Conductance measurements in a frequency range from 10 kHz to 1 MHz are used to characterize the trapping effects in the devices. A new type of trap is observed in the F plasma treated E-HEMT compared with the D-HEMT, but the density of the trap decreases by radiation. Fitting of G p /ω data yields the trap densities D T = (1 − 3) × 10 12 cm −2 · eV −1 and D T = (0.2 − 0.8) × 10 12 cm −2 · eV −1 before and after radiation, respectively. The time constant is 0.5 ms-6 ms. With F plasma treatment, the trap is introduced by etch damage and degrades the electronic mobility. After 60 Co gamma radiation, the etch damage decreases and the electron mobility is improved. The gamma radiation can recover the etch damage caused by F plasma treatment. (interdisciplinary physics and related areas of science and technology)

  17. Comparative analysis of the effects of tantalum doping and annealing on atomic layer deposited (Ta2O5)x(Al2O3)1-x as potential gate dielectrics for GaN/AlxGa1-xN/GaN high electron mobility transistors

    Science.gov (United States)

    Partida-Manzanera, T.; Roberts, J. W.; Bhat, T. N.; Zhang, Z.; Tan, H. R.; Dolmanan, S. B.; Sedghi, N.; Tripathy, S.; Potter, R. J.

    2016-01-01

    This paper describes a method to optimally combine wide band gap Al2O3 with high dielectric constant (high-κ) Ta2O5 for gate dielectric applications. (Ta2O5)x(Al2O3)1-x thin films deposited by thermal atomic layer deposition (ALD) on GaN-capped AlxGa1-xN/GaN high electron mobility transistor (HEMT) structures have been studied as a function of the Ta2O5 molar fraction. X-ray photoelectron spectroscopy shows that the bandgap of the oxide films linearly decreases from 6.5 eV for pure Al2O3 to 4.6 eV for pure Ta2O5. The dielectric constant calculated from capacitance-voltage measurements also increases linearly from 7.8 for Al2O3 up to 25.6 for Ta2O5. The effect of post-deposition annealing in N2 at 600 °C on the interfacial properties of undoped Al2O3 and Ta-doped (Ta2O5)0.12(Al2O3)0.88 films grown on GaN-HEMTs has been investigated. These conditions are analogous to the conditions used for source/drain contact formation in gate-first HEMT technology. A reduction of the Ga-O to Ga-N bond ratios at the oxide/HEMT interfaces is observed after annealing, which is attributed to a reduction of interstitial oxygen-related defects. As a result, the conduction band offsets (CBOs) of the Al2O3/GaN-HEMT and (Ta2O5)0.16(Al2O3)0.84/GaN-HEMT samples increased by ˜1.1 eV to 2.8 eV and 2.6 eV, respectively, which is advantageous for n-type HEMTs. The results demonstrate that ALD of Ta-doped Al2O3 can be used to control the properties of the gate dielectric, allowing the κ-value to be increased, while still maintaining a sufficient CBO to the GaN-HEMT structure for low leakage currents.

  18. The physical process analysis of the capacitance—voltage characteristics of AlGaN/AlN/GaN high electron mobility transistors

    International Nuclear Information System (INIS)

    Xin-Hua, Wang; Miao, Zhao; Xin-Yu, Liu; Yan, Pu; Ying-Kui, Zheng; Ke, Wei

    2010-01-01

    This paper deduces the expression of the Schottky contact capacitance of AlGaN/AlN/GaN high electron mobility transistors (HEMTs), which will help to understand the electron depleting process. Some material parameters related with capacitance-voltage profiling are given in the expression. Detailed analysis of the forward-biased capacitance has been carried on. The gate capacitance of undoped AlGaN/AlN/GaN HEMT will fall under forward bias. If a rising profile is obviously observed, the donor-like impurity or trap is possibly introduced in the barrier. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. Comparative analysis of the effects of tantalum doping and annealing on atomic layer deposited (Ta2O5)x(Al2O3)1−x as potential gate dielectrics for GaN/AlxGa1−xN/GaN high electron mobility transistors

    International Nuclear Information System (INIS)

    Partida-Manzanera, T.; Roberts, J. W.; Sedghi, N.; Potter, R. J.; Bhat, T. N.; Zhang, Z.; Tan, H. R.; Dolmanan, S. B.; Tripathy, S.

    2016-01-01

    This paper describes a method to optimally combine wide band gap Al 2 O 3 with high dielectric constant (high-κ) Ta 2 O 5 for gate dielectric applications. (Ta 2 O 5 ) x (Al 2 O 3 ) 1−x thin films deposited by thermal atomic layer deposition (ALD) on GaN-capped Al x Ga 1−x N/GaN high electron mobility transistor (HEMT) structures have been studied as a function of the Ta 2 O 5 molar fraction. X-ray photoelectron spectroscopy shows that the bandgap of the oxide films linearly decreases from 6.5 eV for pure Al 2 O 3 to 4.6 eV for pure Ta 2 O 5 . The dielectric constant calculated from capacitance-voltage measurements also increases linearly from 7.8 for Al 2 O 3 up to 25.6 for Ta 2 O 5 . The effect of post-deposition annealing in N 2 at 600 °C on the interfacial properties of undoped Al 2 O 3 and Ta-doped (Ta 2 O 5 ) 0.12 (Al 2 O 3 ) 0.88 films grown on GaN-HEMTs has been investigated. These conditions are analogous to the conditions used for source/drain contact formation in gate-first HEMT technology. A reduction of the Ga-O to Ga-N bond ratios at the oxide/HEMT interfaces is observed after annealing, which is attributed to a reduction of interstitial oxygen-related defects. As a result, the conduction band offsets (CBOs) of the Al 2 O 3 /GaN-HEMT and (Ta 2 O 5 ) 0.16 (Al 2 O 3 ) 0.84 /GaN-HEMT samples increased by ∼1.1 eV to 2.8 eV and 2.6 eV, respectively, which is advantageous for n-type HEMTs. The results demonstrate that ALD of Ta-doped Al 2 O 3 can be used to control the properties of the gate dielectric, allowing the κ-value to be increased, while still maintaining a sufficient CBO to the GaN-HEMT structure for low leakage currents

  20. A 99%-efficiency GaN converter for 6.78 MHz magnetic resonant wireless power transfer system

    OpenAIRE

    Yoshiyuki Akuzawa; Yuki Ito; Toshihiro Ezoe; Kiyohide Sakai

    2014-01-01

    The authors developed a high-efficiency gallium-nitride (GaN) Class-E converter for a 6.78 MHz magnetic resonant wireless power transfer system. A negative-bias gate driver circuit made it possible to use a depletion mode GaN high-electron-mobility transistor (HEMT), and simplified the converter circuit. As the depletion mode GaN HEMT with very small gate–source capacitance provided almost ideal zero-voltage switching, the authors attained a drain efficiency of 98.8% and a total efficiency of...

  1. The physical process analysis of the capacitance—voltage characteristics of AlGaN/AlN/GaN high electron mobility transistors

    Science.gov (United States)

    Wang, Xin-Hua; Zhao, Miao; Liu, Xin-Yu; Pu, Yan; Zheng, Ying-Kui; Wei, Ke

    2010-09-01

    This paper deduces the expression of the Schottky contact capacitance of AlGaN/AlN/GaN high electron mobility transistors (HEMTs), which will help to understand the electron depleting process. Some material parameters related with capacitance-voltage profiling are given in the expression. Detailed analysis of the forward-biased capacitance has been carried on. The gate capacitance of undoped AlGaN/AlN/GaN HEMT will fall under forward bias. If a rising profile is obviously observed, the donor-like impurity or trap is possibly introduced in the barrier.

  2. Reactive ion etching of GaSb, (Al,Ga)Sb, and InAs for novel device applications

    International Nuclear Information System (INIS)

    LaTulipe, D.C.; Frank, D.J.; Munekata, H.

    1991-01-01

    Although a variety of novel device proposals for GaSb/(Al,Ga)Sb/InAs heterostructures have been made, relatively little is known about processing these materials. The authors of this paper have studied the reactive ion etching characteristics of GaSb, (Al,Ga)Sb, and InAs in both methane/hydrogen and chlorine gas chemistries. At conditions similar to those reported elsewhere for RIE of InP and GaAs in CH 4 /H 2 , the etch rate of (Al,Ga)Sb was found to be near zero, while GaSb and InAs etched at 200 Angstrom/minute. Under conditions where the etch mechanism is primarily physical sputtering, the three compounds etch at similar rates. Etching in Cl 2 was found to yield anistropic profiles, with the etch rate of (Al,Ga)Sb increasing with Al mole fraction, while InAs remains unetched. Damage to the InAs stop layer was investigated by sheet resistance and mobility measurements. These etching techniques were used to fabricate a novel InAs- channel FET composed of these materials. Several scanning electron micrographs of etching results are shown along with preliminary electrical characteristics

  3. Cyanide- and phenoxo-bridged heterobimetallic Fe(III)-Mn(III ...

    Indian Academy of Sciences (India)

    Chem. 48 2956; (b) Kim Jae II, Yoo H S, Koh E. K, Kim H C and Hong C S 2007 Inorg. Chem. 46 8481;. (c) Yoo I Y Ryu D W, Yoon J H, Sohn A R, Lim K S,. Cho B K, Koh E K and Hong C S 2012 Dalton Trans. 41. 1776; (d) Senapati T, Pichon, C Ababei R Mathonière C and Clérac R 2012 Inorg. Chem. 51 3796; (e) Kim Jae.

  4. RESEARCH ARTICLE Genetic analysis of drug-metabolizing phase ...

    Indian Academy of Sciences (India)

    Navya

    Uighur, Hui and Mongolian populations were 0.8162, 0.8598, 0.8079, 0.7975, respectively. (ZUO et al. 2012). The differences .... Lee JS., Cheong HS., Kim LH., Kim JO., Seo DW., Kim YH et al. 2013 Screening of genetic ... enzymes CYP3A4, CYP2C9, CYP2C19 and CYP2D6 in Han, Uighur, Hui and. Mongolian Chinese ...

  5. Contribution of p75NTR to Schwannoma Growth and Therapeutic Responses

    Science.gov (United States)

    2015-05-01

    284-291. Hansen MR, Roehm PC, Chatterjee P, Green SH (2006) Constitutive neuregulin-1/ErbB signaling contributes to human vestibular schwannoma... vestibular schwannoma. Human molecular genetics 3:347-350. Jung KM, Tan S, Landman N, Petrova K, Murray S, Lewis R, Kim PK, Kim DS, Ryu SH, Chao MV, Kim...culture and in animal models of human schwannoma disease . We find that the NF2 gene product, merlin, regulates p75NTR expression levels and signaling

  6. Facile synthesis and characterization of CsPbBr3 and CsPb2Br5 ...

    Indian Academy of Sciences (India)

    2018-03-23

    Mar 23, 2018 ... [4] Yang W S, Noh J H, Jeon N J, Kim Y C, Ryu S, Seo J et al. 2015 Science 348 1234. [5] Tan Z K, Moghaddam R S, Lai M L, Docampo P, Higler R,. Deschler F et al 2014 Nat. Nanotechnol. 9 687. [6] Kim Y H, Cho H, Heo J H, Kim T S, Myoung N, Lee C L et al. 2015 Adv. Mater. 27 1248. [7] Zhang Q, Ha S T, ...

  7. An efficient synthesis of quinolines under solvent-free conditions

    Indian Academy of Sciences (India)

    Unknown

    (a) Cho C S, Kim B T, Kim T-J and Shim S C 2001. Chem. Commun. 2576; (b) McNaughton B R and. Miller B L 2003 Org. Lett. 5 4257 (c) Ranu B C, Ha- jra A, Dey S S and Jana U 2003 Tetrahedron 59 813;. (d) Song S J, Cho S J, Park D K, Kwon T W and. Jenekhe S A 2003 Tetrahedron Lett. 44 255; (e) Cho. C S, Kim B T ...

  8. The relationship between fat depot-specific preadipocyte differentiation and metabolic syndrome in obese women

    Directory of Open Access Journals (Sweden)

    N V Mazurina

    2013-03-01

    Full Text Available Реферат по материалам статьи The relationship between fat depot-specific preadipocyte differentiation and metabolic syndrome in obese women. Park HТ, Lee ES, Cheon EP, Lee DR, Yang K-S, Kim YT, Hur JY, Kim SH, Lee KW, Kim T. Clinical Endocrinology 2012; 76, 59-66.

  9. Akadeemik Jevgeni Viktorovitš Tarle - Tartu Ülikooli üldajaloo professor 1913-1918 / Ljudmila Dubjeva

    Index Scriptorium Estoniae

    Dubjeva, Ljudmila, 1954-

    2006-01-01

    Rahvusvaheliselt tunnustatud ajaloolase Jevgeni Tarle valimisest Tartu ülikooli professoriks 1912. Hans Kruusi meenutustest Tarlest Tartu ülikooli õppejõuna. Tartu periood oli Tarle elus suhteliselt vähemtähtis lõik. Ta lahkus Tartust 1918. aastal siirdudes Petrogradi

  10. Damage effect and mechanism of the GaAs high electron mobility transistor induced by high power microwave

    Science.gov (United States)

    Yang, Liu; Chang-Chun, Chai; Yin-Tang, Yang; Jing, Sun; Zhi-Peng, Li

    2016-04-01

    In this paper, we present the damage effect and mechanism of high power microwave (HPM) on AlGaAs/GaAs pseudomorphic high-electron-mobility transistor (pHEMT) of low-noise amplifier (LNA). A detailed investigation is carried out by simulation and experiment study. A two-dimensional electro-thermal model of the typical GaAs pHEMT induced by HPM is established in this paper. The simulation result reveals that avalanche breakdown, intrinsic excitation, and thermal breakdown all contribute to damage process. Heat accumulation occurs during the positive half cycle and the cylinder under the gate near the source side is most susceptible to burn-out. Experiment is carried out by injecting high power microwave into GaAs pHEMT LNA samples. It is found that the damage to LNA is because of the burn-out at first stage pHEMT. The interiors of the damaged samples are observed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). Experimental results accord well with the simulation of our model. Project supported by the National Basic Research Program of China (Grant No. 2014CB339900) and the Open Fund of Key Laboratory of Complex Electromagnetic Environment Science and Technology, China Academy of Engineering Physics (Grant No. 2015-0214.XY.K).

  11. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics. Das B. Articles written in Pramana – Journal of Physics. Volume 86 Issue 4 April 2016 pp 723-736 Regular. A physics-based potential and electric field model of a nanoscale rectangular high-K gate dielectric HEMT · Das B Goswami R Bhowmick B · More Details Abstract ...

  12. Suitability of GaN and LDMOS for 70–82% efficiency 120–200W HPA addressing spaceborne P-band radar applications

    DEFF Research Database (Denmark)

    Le Gallou, N.; Vidkjær, Jens; Poivey, C.

    2012-01-01

    This paper addresses the development of P-band (435 MHz) HPA based on different technologies (GaN HEMT, LDMOS FET) for future use in pace radar applications in the context of the Biomass project. In particular best in class PAE of 70%–82% is targeted and achieved for power levels of 120W. In orde...

  13. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics. Bhowmick B. Articles written in Pramana – Journal of Physics. Volume 86 Issue 4 April 2016 pp 723-736 Regular. A physics-based potential and electric field model of a nanoscale rectangular high-K gate dielectric HEMT · Das B Goswami R Bhowmick B · More Details ...

  14. Suitability of GaN and LDMOS for 70–82% efficiency 120–200W HPA addressing spaceborne P-band radar applications

    DEFF Research Database (Denmark)

    Le Gallou, N.; Vidkjær, Jens; Poivey, C.

    2012-01-01

    This paper addresses the development of P-band (435 MHz) HPA based on different technologies (GaN HEMT, LDMOS FET) for future use in pace radar applications in the context of the Biomass project. In particular best in class PAE of 70%–82% is targeted and achieved for power levels of 120W. In order...

  15. Current linearity and operation stability in Al2O3-gate AlGaN/GaN MOS high electron mobility transistors

    Science.gov (United States)

    Nishiguchi, Kenya; Kaneki, Syota; Ozaki, Shiro; Hashizume, Tamotsu

    2017-10-01

    To investigate current linearity and operation stability of metal-oxide-semiconductor (MOS) AlGaN/GaN high electron mobility transistors (HEMTs), we have fabricated and characterized the Al2O3-gate MOS-HEMTs without and with a bias annealing in air at 300 °C. Compared with the as-fabricated (unannealed) MOS HEMTs, the bias-annealed devices showed improved linearity of I D-V G curves even in the forward bias regime, resulting in increased maximum drain current. Lower subthreshold slope was also observed after bias annealing. From the precise capacitance-voltage analysis on a MOS diode fabricated on the AlGaN/GaN heterostructure, it was found that the bias annealing effectively reduced the state density at the Al2O3/AlGaN interface. This led to efficient modulation of the AlGaN surface potential close to the conduction band edge, resulting in good gate control of two-dimensional electron gas density even at forward bias. In addition, the bias-annealed MOS HEMT showed small threshold voltage shift after applying forward bias stress and stable operation even at high temperatures.

  16. A study on multiple defect states in low-carbon doped GaN layers and its correlation with AlGaN/GaN high electron mobility transistor operation

    International Nuclear Information System (INIS)

    Tanaka, Takeshi; Shiojima, Kenji; Otoki, Yohei; Tokuda, Yutaka

    2014-01-01

    A study on defect states in relatively low-carbon doped GaN is presented. A large current collapse was observed in AlGaN/GaN high electron mobility transistor (HEMT) operation when the device channel was doped with carbon of 1 × 10 17 cm −3 . Deep level transient spectroscopy measurements showed a positive and even negative correlation between the densities of carbon and those of shallow trap states. Along with their small concentrations, shallow traps could not be associated with the collapse of the HEMT. Photo capacitance measurements yielded large signal at very deep levels of 1.6 and 2.4 eV in carbon doped GaN. Especially, the 2.4 eV deep trap was estimated to be acceptor type and related to some indirect states that the minority carrier transient spectroscopy could not characterize. A 20% of doped carbon was allocated to the very deep traps, and the large current collapse was attributed to these carbon-related states. - Highlights: • Systematic study on role of carbon in AlGaN/GaN HEMT structures was attempted. • Large current collapse was observed at HEMT operation in carbon doped channel. • Photo capacitance measurements yielded large signal at very deep levels. • The large current degradation was attributed to the carbon-related deep traps

  17. AlGaN/GaN high electron mobility transistor with Al2O3+BCB passivation

    International Nuclear Information System (INIS)

    Zhang Sheng; Yu Le; Ma Xiao-Hua; Wei Ke; Liu Guo-Guo; Huang Sen; Wang Xin-Hua; Pang Lei; Zheng Ying-Kui; Li Yan-Kui; Sun Bing; Liu Xin-Yu

    2015-01-01

    In this paper, Al 2 O 3 ultrathin film used as the surface passivation layer for AlGaN/GaN high electron mobility transistor (HEMT) is deposited by thermal atomic layer deposition (ALD), thereby avoiding plasma-induced damage and erosion to the surface. A comparison is made between the surface passivation in this paper and the conventional plasma enhanced chemical vapor deposition (PECVD) SiN passivation. A remarkable reduction of the gate leakage current and a significant increase in small signal radio frequency (RF) performance are achieved after applying Al 2 O 3 +BCB passivation. For the Al 2 O 3 +BCB passivated device with a 0.7 μm gate, the value of f max reaches up to 100 GHz, but it decreases to 40 GHz for SiN HEMT. The f max /f t ratio (≥ 4) is also improved after Al 2 O 3 +BCB passivation. The capacitance–voltage (C–V) measurement demonstrates that Al 2 O 3 +BCB HEMT shows quite less density of trap states (on the order of magnitude of 10 10  cm −2 ) than that obtained at commonly studied SiN HEMT. (paper)

  18. Threshold Voltage Instability in Al2O3/GaN/AlGaN/GaN Metal-Insulator-Semiconductor High-Electron Mobility Transistors

    Science.gov (United States)

    Huang, Sen; Yang, Shu; Roberts, John; Chen, Kevin J.

    2011-11-01

    The threshold voltage (Vth) instability in GaN-based metal-insulator-semiconductor high-electron mobility transistors (MIS-HEMTs) with 15-nm atomic-layer-deposited (ALD) Al2O3 as gate dielectrics is systematically investigated by dc current-voltage (I-V), high-frequency capacitance-voltage (C-V) (HFCV), and quasi-static C-V (QSCV) characterizations. Both Al2O3/GaN/AlGaN/GaN MIS diode and GaN/AlGaN/GaN Schottky diode only exhibit tiny threshold-voltage hysteresis (ΔVth) (HEMTs is thus studied by increasing the maximum VGS (VGSmax) in the measurement of transfer characteristics. Significant positive Vth shift occurred once the VGSmax exceeds +1 V, while such Vth-instability is still absent in Schottky-gate AlGaN/GaN HEMTs. It is suggested that the acceptor-like deep states at Al2O3/GaN interface account for the Vth-instability in Al2O3/GaN/AlGaN/GaN MIS-HEMTs. As the filling and emission processes of these interface states are slow, they are successfully captured by low-frequency QSCV techniques.

  19. AlGaN/GaN high electron mobility transistor with Al2O3+BCB passivation

    Science.gov (United States)

    Zhang, Sheng; Wei, Ke; Yu, Le; Liu, Guo-Guo; Huang, Sen; Wang, Xin-Hua; Pang, Lei; Zheng, Ying-Kui; Li, Yan-Kui; Ma, Xiao-Hua; Sun, Bing; Liu, Xin-Yu

    2015-11-01

    In this paper, A12O3 ultrathin film used as the surface passivation layer for AlGaN/GaN high electron mobility transistor (HEMT) is deposited by thermal atomic layer deposition (ALD), thereby avoiding plasma-induced damage and erosion to the surface. A comparison is made between the surface passivation in this paper and the conventional plasma enhanced chemical vapor deposition (PECVD) SiN passivation. A remarkable reduction of the gate leakage current and a significant increase in small signal radio frequency (RF) performance are achieved after applying Al2O3+BCB passivation. For the Al2O3+BCB passivated device with a 0.7 μm gate, the value of fmax reaches up to 100 GHz, but it decreases to 40 GHz for SiN HEMT. The fmax/ft ratio (≥ 4) is also improved after Al2O3+BCB passivation. The capacitance-voltage (C-V) measurement demonstrates that Al2O3+BCB HEMT shows quite less density of trap states (on the order of magnitude of 1010 cm-2) than that obtained at commonly studied SiN HEMT.

  20. Effects of process temperature during atomic layer deposition using water and ozone as oxidants on current-voltage characteristics of Al2O3/AlGaN/GaN high-electron-mobility transistors on Si substrates

    Science.gov (United States)

    Kubo, Toshiharu; Freedsman, Joseph J.; Yoshida, Yusuke; Egawa, Takashi

    2015-02-01

    Atomic layer deposition (ALD) using both water (H2O) and ozone (O3) as oxidants was performed to fabricate Al2O3/AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) on Si substrates, and the effects of deposition temperature on the electrical characteristics of these MIS-HEMTs were investigated using DC and pulsed current-voltage measurements. The MIS-HEMT with Al2O3 deposited at 250 °C showed less drain current degradation in pulsed measurements, which was consistent with the low minimum interface state density of 0.9 × 1010 cm-2 eV-1 estimated from the photo-assisted capacitance-voltage shift. These results indicate that the Al2O3 layer for GaN-based MIS-HEMTs can be fabricated by the H2O+O3-based ALD process at a relatively low temperature of 250 °C.

  1. A study on multiple defect states in low-carbon doped GaN layers and its correlation with AlGaN/GaN high electron mobility transistor operation

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Takeshi, E-mail: takeshi.tanaka.jf@hitachi-metals.com [Graduate School of Electrical and Electronics Engineering, University of Fukui (Japan); Engineering Dept., Compound Semiconductor Products Business Unit, Cable Materials Company, Hitachi Metals, Ltd., Isagozawa 880, Hitachi City, Ibaraki 319-1418 (Japan); Shiojima, Kenji [Graduate School of Electrical and Electronics Engineering, University of Fukui (Japan); Otoki, Yohei [Engineering Dept., Compound Semiconductor Products Business Unit, Cable Materials Company, Hitachi Metals, Ltd., Isagozawa 880, Hitachi City, Ibaraki 319-1418 (Japan); Tokuda, Yutaka [Department of Electrical and Electronics Engineering, Aichi Institute of Technology (Japan)

    2014-04-30

    A study on defect states in relatively low-carbon doped GaN is presented. A large current collapse was observed in AlGaN/GaN high electron mobility transistor (HEMT) operation when the device channel was doped with carbon of 1 × 10{sup 17} cm{sup −3}. Deep level transient spectroscopy measurements showed a positive and even negative correlation between the densities of carbon and those of shallow trap states. Along with their small concentrations, shallow traps could not be associated with the collapse of the HEMT. Photo capacitance measurements yielded large signal at very deep levels of 1.6 and 2.4 eV in carbon doped GaN. Especially, the 2.4 eV deep trap was estimated to be acceptor type and related to some indirect states that the minority carrier transient spectroscopy could not characterize. A 20% of doped carbon was allocated to the very deep traps, and the large current collapse was attributed to these carbon-related states. - Highlights: • Systematic study on role of carbon in AlGaN/GaN HEMT structures was attempted. • Large current collapse was observed at HEMT operation in carbon doped channel. • Photo capacitance measurements yielded large signal at very deep levels. • The large current degradation was attributed to the carbon-related deep traps.

  2. Measurement of the transient response of semiconductor devices to ionizing radiation

    International Nuclear Information System (INIS)

    McMorrow, Dale; Boos, J. Brad; Melinger, Joseph S.; Ferlet-Cavrois, Veronique; Paillet, Philippe; Duhamel, Olivier; Baggio, Jacques

    2007-01-01

    Recent developments in the measurement of heavy-ion induced charge-collection transients of semiconductor devices are described. The information content of transient SET measurement is significantly enhanced relative to that of conventional charge-collection measurement. Examples of recent measurements on InP HEMT and SOI NMOS devices are presented

  3. Modeling of thermal stress induced during the diamond-coating of ALGaN/GaN high electron mobility transistors

    Czech Academy of Sciences Publication Activity Database

    Jirásek, Vít; Ižák, Tibor; Babchenko, Oleg; Kromka, Alexander; Vanko, G.

    2013-01-01

    Roč. 5, č. 6 (2013), s. 522-526 ISSN 2164-6627 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : nano-crystalline diamond * gallium nitride * HEMT * selective diamond growth Subject RIV: BM - Solid Matter Physics ; Magnetism

  4. GaN-Based High-k Praseodymium Oxide Gate MISFETs with P2S5/(NH42SX + UV Interface Treatment Technology

    Directory of Open Access Journals (Sweden)

    Chao-Wei Lin

    2012-01-01

    Full Text Available This study examines the praseodymium-oxide- (Pr2O3- passivated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs with high dielectric constant in which the AlGaN Schottky layers are treated with P2S5/(NH42SX + ultraviolet (UV illumination. An electron-beam evaporated Pr2O3 insulator is used instead of traditional plasma-assisted chemical vapor deposition (PECVD, in order to prevent plasma-induced damage to the AlGaN. In this work, the HEMTs are pretreated with P2S5/(NH42SX solution and UV illumination before the gate insulator (Pr2O3 is deposited. Since stable sulfur that is bound to the Ga species can be obtained easily and surface oxygen atoms are reduced by the P2S5/(NH42SX pretreatment, the lowest leakage current is observed in MIS-HEMT. Additionally, a low flicker noise and a low surface roughness (0.38 nm are also obtained using this novel process, which demonstrates its ability to reduce the surface states. Low gate leakage current Pr2O3 and high-k AlGaN/GaN MIS-HEMTs, with P2S5/(NH42SX + UV illumination treatment, are suited to low-noise applications, because of the electron-beam-evaporated insulator and the new chemical pretreatment.

  5. Modeling of thermal stress induced during the diamond-coating of AlGaN/GaN high electron mobility transistors

    Czech Academy of Sciences Publication Activity Database

    Jirásek, V.; Ižák, Tibor; Babchenko, Oleg; Kromka, Alexander; Vanko, G.

    2013-01-01

    Roč. 5, č. 6 (2013), s. 522-526 ISSN 2164-6627 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : gallium nitride * HEMT * nano-crystalline diamond * selective diamond growth Subject RIV: BM - Solid Matter Physics ; Magnetism http://dx.doi.org/10.1166/asem.2013.1324.

  6. Strain-effect transistors: Theoretical study on the effects of external strain on III-nitride high-electron-mobility transistors on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Shervin, Shahab; Asadirad, Mojtaba [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Materials Science and Engineering Program, University of Houston, Houston, Texas 77204 (United States); Kim, Seung-Hwan; Ravipati, Srikanth; Lee, Keon-Hwa [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Bulashevich, Kirill [STR Group, Inc., Engels av. 27, P.O. Box 89, 194156, St. Petersburg (Russian Federation); Ryou, Jae-Hyun, E-mail: jryou@uh.edu [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Materials Science and Engineering Program, University of Houston, Houston, Texas 77204 (United States); Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, Texas 77204 (United States)

    2015-11-09

    This paper presents strain-effect transistors (SETs) based on flexible III-nitride high-electron-mobility transistors (HEMTs) through theoretical calculations. We show that the electronic band structures of InAlGaN/GaN thin-film heterostructures on flexible substrates can be modified by external bending with a high degree of freedom using polarization properties of the polar semiconductor materials. Transfer characteristics of the HEMT devices, including threshold voltage and transconductance, are controlled by varied external strain. Equilibrium 2-dimensional electron gas (2DEG) is enhanced with applied tensile strain by bending the flexible structure with the concave-side down (bend-down condition). 2DEG density is reduced and eventually depleted with increasing compressive strain in bend-up conditions. The operation mode of different HEMT structures changes from depletion- to enchantment-mode or vice versa depending on the type and magnitude of external strain. The results suggest that the operation modes and transfer characteristics of HEMTs can be engineered with an optimum external bending strain applied in the device structure, which is expected to be beneficial for both radio frequency and switching applications. In addition, we show that drain currents of transistors based on flexible InAlGaN/GaN can be modulated only by external strain without applying electric field in the gate. The channel conductivity modulation that is obtained by only external strain proposes an extended functional device, gate-free SETs, which can be used in electro-mechanical applications.

  7. Detection of prostate-specific antigen with biomolecule-gated AlGaN/GaN high electron mobility transistors

    International Nuclear Information System (INIS)

    Li, Jia-dong; Miao, Bin; Wei, Xiao-wei; Xie, Jie; Wu, Dong-min; Cheng, Jun-jie; Zhang, Jin-cheng; Zhang, Zhi-qiang

    2014-01-01

    In order to improve the sensitivity of AlGaN/GaN high electron mobility transistor (HEMT) biosensors, a simple biomolecule-gated AlGaN/GaN HEMT structure was designed and successfully fabricated for prostate specific antigen (PSA) detection. UV/ozone was used to oxidize the GaN surface and then a 3-aminopropyl trimethoxysilane (APTES) self-assembled monolayer was bound to the sensing region. This monolayer serves as a binding layer for attachment of the prostate specific antibody (anti-PSA). The biomolecule-gated AlGaN/GaN HEMT sensor shows a rapid and sensitive response when the target prostate-specific antigen in buffer solution was added to the antibody-immobilized sensing area. The current change showed a logarithm relationship against the PSA concentration from 0.1 pg/ml to 0.993 ng/ml. The sensitivity of 0.215% is determined for 0.1 pg/ml PSA solution. The above experimental result of the biomolecule-gated AlGaN/GaN HEMT biosensor suggested that this biosensor might be a useful tool for prostate cancer screening. (paper)

  8. High frequency MOSFET gate drivers technologies and applications

    CERN Document Server

    Zhang, Zhiliang

    2017-01-01

    This book describes high frequency power MOSFET gate driver technologies, including gate drivers for GaN HEMTs, which have great potential in the next generation of switching power converters. Gate drivers serve as a critical role between control and power devices.

  9. Modelling of capacitance and threshold voltage for ultrathin normally ...

    Indian Academy of Sciences (India)

    2016-12-02

    Dec 2, 2016 ... The MATLAB- based simulation results of the developed model are compared graphically with the experimental results from the literature presented in §3. Finally the con- clusion has been drawn in §4. 2. Model development. The basic expression for sheet charge concentration in. HEMT device is given by ...

  10. High radiation tolerance of InAs/AlSb high-electron-mobility transistors

    International Nuclear Information System (INIS)

    Weaver, B.D.; Boos, J.B.; Papanicolaou, N.A.; Bennett, B.R.; Park, D.; Bass, R.

    2005-01-01

    InAs/AlSb-based high-electron-mobility transistors (HEMTs) were irradiated with 2 MeV protons. Radiation damage caused the source-drain current I ds to decrease nearly linearly with fluence Φ at a rate of Δ[I ds (Φ)/I ds (0)]/ΔΦ≅7x10 -16 cm 2 . Radiation-induced decreases in I ds have been observed for other HEMT material systems, and have been attributed to high-efficiency defect-induced scattering of carriers out of the two-dimensional electron gas. However, in the InAs/AlSb system the rate of decrease of I ds is about 140 times less than that for typical GaAs/AlGaAs HEMTs. An explanation is presented in which the high radiation tolerance of InAs/AlSb HEMTs is related to carrier reinjection and the unusually large energy offset between the AlSb barriers and the InAs quantum well

  11. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 4. Issue front cover thumbnail. Volume 86, Issue 4. April 2016, pages 723-946. pp 723-736 Regular. A physics-based potential and electric field model of a nanoscale rectangular high-K gate dielectric HEMT · Das B Goswami R Bhowmick B · More Details ...

  12. Isolated Photosystem I Reaction Centers on a Functionalized Gated High Electron Mobility Transistor

    Energy Technology Data Exchange (ETDEWEB)

    Eliza, Sazia A. [University of Tennessee, Knoxville (UTK); Lee, Ida [ORNL; Tulip, Fahmida S [ORNL; Islam, Syed K [University of Tennessee, Knoxville (UTK); Mostafa, Salwa [University of Tennessee, Knoxville (UTK); Greenbaum, Elias [ORNL; Ericson, Milton Nance [ORNL

    2011-01-01

    In oxygenic plants, photons are captured with high quantum efficiency by two specialized reaction centers (RC) called Photosystem I (PS I) and Photosystem II (PS II). The captured photon triggers rapid charge separation and the photon energy is converted into an electrostatic potential across the nanometer-scale nm reaction centers. The exogenous photovoltages from a single PS I RC have been previously measured using the technique of Kelvin force probe microscopy (KFM). However, biomolecular photovoltaic applications require two-terminal devices. This paper presents for the first time, a micro-device for detection and characterization of isolated PS I RCs. The device is based on an AlGaN/GaN high electron mobility transistor (HEMT) structure. AlGaN/GaN HEMTs show high current throughputs and greater sensitivity to surface charges compared to other field-effect devices. PS I complexes immobilized on the floating gate of AlGaN/GaN HEMTs resulted in significant changes in the device characteristics under illumination. An analytical model has been developed to estimate the RCs of a major orientation on the functionalized gate surface of the HEMTs.

  13. Careers in STEM Begin with Elementary Student Interest in Mathematics

    Science.gov (United States)

    Brimmer, Linda Ertrachter

    2017-01-01

    I investigated why math capable students are not entering science, technology, engineering, and math (STEM) careers. To research the problem, I explored how highly effective elementary math teachers (HEMT) create student interest in mathematics using the self- efficacy (SE) theory and information and communication technology (ICT). The purpose of…

  14. Urban / Heidi Purga

    Index Scriptorium Estoniae

    Purga, Heidy, 1975-

    2005-01-01

    Uutest heliplaatidest Earth, Wind & Fire "Illumination", Kanye West "Late Registration", Stereo MC's "Paradise", Shaggy "Clothes Drop", Lil Kim "The Naked Truth", Babyface "Grown and Sexy", Sean Paul "Trinity"

  15. A Genome-wide Breast Cancer Scan in African Americans

    Science.gov (United States)

    2012-06-01

    immortal cells and cancer. Science 266:2011–2015 Kim HC, Lee JY, Sung H, Choi JY, Park SK, Lee KM, Kim YJ, Go MJ, Li L, Cho YS, Park M, Kim DJ, Oh JH...Brown WM, Petruzella S, Thacker EL, Kim Y, Nalls MA, Tranah GJ, Sung YJ, Ambrosone CB, Arnett D, Bandera EV, Becker DM, Becker L, Berndt SI...MA, Prowse KR, Harley CB, West MD, Ho PL, Coviello GM, Wright WE, Weinrich SL, Shay JW (1994) Specific association of human telomerase activity with

  16. Application of the Single Hardening Model in the Finite Element Program ABAQUS

    DEFF Research Database (Denmark)

    Jakobsen, Kim Parsberg

    or in combined deformation and flow problems. Today, many of these problems are solved using various finite element computer softwares, capable of handling both geometric and material non-linearities. The latter is especially important in soil mechanics and soil-structure interaction problems. Despite the feat...... model, developed by Lade and Kim (Kim & Lade 1988, Lade & Kim 1988a, Lade & Kim 1988b) is implemented as a user defined material module, UMAT, in the commercial finite element program, ABAQUS. The advantages of the Single Hardening Model Iie in its ability to predict elastic and plastic displacements...

  17. Pop / Raul Saaremets

    Index Scriptorium Estoniae

    Saaremets, Raul

    2002-01-01

    Heliplaatidest Starsailor" Love is Here". Chicago Underground Quartet "Chicago Underground Quartet". Mower "Mower". Kim Wilde "The Very Best of". Mull Historical Society "Loss". Jill Scott "Experience: 826+"

  18. LUNAR TERRAIN AND ALBEDO RECONSTRUCTION FROM APOLLO IMAGERY

    Data.gov (United States)

    National Aeronautics and Space Administration — LUNAR TERRAIN AND ALBEDO RECONSTRUCTION FROM APOLLO IMAGERY ARA V NEFIAN*, TAEMIN KIM, MICHAEL BROXTON, AND ZACH MORATTO Abstract. Generating accurate three...

  19. Is urinary kidney injury molecule-1 a noninvasive marker for renal injury in patients with ureteral stones?

    Directory of Open Access Journals (Sweden)

    Lokman Irkilata

    2016-06-01

    Conclusions: Elevated urinary KIM-1 levels at the end of the first month after URS indicate continued renal injury due to ureteral stone. The degree of hydronephrosis was proportional to the level of urinary KIM-1. The degree of hydronephrosis at postoperative day 30 is the most important factor determining KIM-1 levels. Neither the localization of the ureteral stone nor the size of the stone are important in determining KIM-1 levels. [Arch Clin Exp Surg 2016; 5(2.000: 65-69

  20. Evaluation of ginsenoside bioconversion of lactic acid bacteria isolated from kimchi.

    Science.gov (United States)

    Park, Boyeon; Hwang, Hyelyeon; Lee, Jina; Sohn, Sung-Oh; Lee, Se Hee; Jung, Min Young; Lim, Hyeong In; Park, Hae Woong; Lee, Jong-Hee

    2017-10-01

    Panax ginseng is a physiologically active plant widely used in traditional medicine that is characterized by the presence of ginsenosides. Rb1, a major ginsenoside, is used as the starting material for producing ginsenoside derivatives with enhanced pharmaceutical potentials through chemical, enzymatic, or microbial transformation. To investigate the bioconversion of ginsenoside Rb1, we prepared kimchi originated bacterial strains Leuconostoc mensenteroides WiKim19, Pediococcus pentosaceus WiKim20, Lactobacillus brevis WiKim47 , Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49 and analyzed bioconversion products using LC-MS/MS mass spectrometer. L. mesenteroides WiKim19 and Pediococcus pentosaceus WiKim20 converted ginsenoside Rb1 into the ginsenoside Rg3 approximately five times more than Lactobacillus brevis WiKim47 , Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49. L mesenteroides WIKim19 showed positive correlation with β-glucosidase activity and higher transformation ability of ginsenoside Rb1 into Rg3 than the other strains whereas, P. pentosaceus WiKim20 showed an elevated production of Rb3 even with lack of β-glucosidase activity but have the highest acidity among the five lactic acid bacteria (LAB). Ginsenoside Rg5 concentration of five LABs have ranged from ∼2.6 μg/mL to 6.5 μg/mL and increased in accordance with the incubation periods. Our results indicate that the enzymatic activity along with acidic condition contribute to the production of minor ginsenoside from lactic acid bacteria.

  1. Comparison of biomarkers in rat renal ischemia-reperfusion injury

    Science.gov (United States)

    Peng, Hongying; Mao, Yan; Fu, Xiaoya; Feng, Zhipeng; Xu, Jun

    2015-01-01

    To observe the expressions of monocyte chemoattractant protein -l (MCP-l), kidney injury molecule -l (KIM-l) and cystatin C (Cys C) in different periods of rat ischemic acute kidney injury (iAKI). The rat renal ischemia-reperfusion injury (IRI) model was prepared, including the sham-operation (Sham) group and the I/R group. The specimens were collected at different time points after iAKI. The expressions of MCP-1, KIM-1 and Cys C of the I/R group were increased earlier than Scr and Urea (I/R group vs. Sham group; P < 0.01). The serum MCP-1 of the I/R group was earliest increased (MCP-1 vs. KIM-1, Cys C and Scr, P < 0.01). Followed by KIM-1 and Cys C; and in the urine samples, the KIM-1 expression was the most sensitive (KIM-1 vs. MCP-1, Cys C and Scr, P < 0.01). The immunohistochemical results showed the kidney of the Sham group almost had no expression, while that of the I/R group significantly expressed MCP-1, KIM-1 and Cys C (I/R group vs. Sham group; P < 0.01). MCP-1, KIM-1 and Cys C had important predictive values towards AKI, and MCP-1 and KIM-1 were superior to Cys C. Different biomarkers had different sensitivities: MCP-1 was earliest increased in serum while lasted shortly, KIM-1 was earliest increased in urine and kept increasing, thus the detection of urinary KIM-1 might be much more suitable in clinics. PMID:26221302

  2. Tubular markers are associated with decline in kidney function in proteinuric type 2 diabetic patients

    DEFF Research Database (Denmark)

    Nielsen, Stine; Reinhard, Henrik; Zdunek, Dietmar

    2012-01-01

    Our aim was to investigate u-NGAL, u-KIM1 and p-FGF23 and prediction of decline in kidney function in type 2 diabetic patients with proteinuria.......Our aim was to investigate u-NGAL, u-KIM1 and p-FGF23 and prediction of decline in kidney function in type 2 diabetic patients with proteinuria....

  3. Characteristics of binding sites of intergenic, intronic and exonic ...

    African Journals Online (AJOL)

    user

    2013-03-06

    2005). DTL. Denticleless homolog (Drosophila). Baraniskin et al. (2012). EBF3. Early B-cell factor 3. Kim and Kim (2007). EGFL7. EGF-like-domain, multiple 7. Díaz et al. (2008). EIF4H. Eukaryotic translation initiation factor 4H.

  4. Snapshots from a leading eco-city

    DEFF Research Database (Denmark)

    Mehlsen, Camilla

    2009-01-01

    The government of Singapore wants to make Singapore the leading Eco-city in Asia. Professor Kim Chuan Goh explains why this might be an achievable goal.......The government of Singapore wants to make Singapore the leading Eco-city in Asia. Professor Kim Chuan Goh explains why this might be an achievable goal....

  5. Susceptibility of Selected Multi-Drug Resistant Clinical Isolates to ...

    African Journals Online (AJOL)

    2018-03-01

    Mar 1, 2018 ... pharmacological potentials that could show efficiency in the treatment of bacterial infections. Keywords: Carpolobia lutea, antifungal, antibacterial, multi-drug ..... Antimicrobial Resistance 2016;7: 41-144. 21. Yoon Y, Kim J, Sohn J, Yang K, Kim M. Role of piperacillin/tazobactam as a carbapenem-sparing.

  6. Fulltext PDF

    Indian Academy of Sciences (India)

    microscopy (SEM) of samples is carried out using Carl Zeiss make (model: l EVO ma 15) equipment and the compositions are verified using energy dispersive ..... 2000 Colossal magneto resistance oxides. (London: Gordon and Breach). [6] Dho J, Kim I, Lee S, Kim K H, Lee H J, Jung J H and. Noh T W 1999 Phys. Rev.

  7. Assessment of Mindfulness with the French Version of the Kentucky Inventory of Mindfulness Skills in Community and Borderline Personality Disorder Samples

    Science.gov (United States)

    Nicastro, Rosetta; Jermann, Francoise; Bondolfi, Guido; McQuillan, Annabel

    2010-01-01

    This article explores mindfulness skills in community and borderline personality disorder (BPD) samples. Study 1 includes 173 community volunteers and explores the psychometric properties of the French version of the Kentucky Inventory of Mindfulness Skills (KIMS). Study 2 explores the KIMS factor structure in 130 BPD patients and compares KIMS…

  8. EGM2008

    African Journals Online (AJOL)

    Nana Kwasi Peprah

    Lee, S. and Kim, C. (2008), “Evaluation of EGM2008 earth geopotential model using. GPS/levelling data”, Journal of the Korean Society for Geospatial Information. System, Vol. 16, pp. 117-126. Lee, S., Kim, J., Jung, Y., Choi, J and Choi, C. (2012), “Implementation of the Distributed. Parallel Program for Geoid Heights ...

  9. Effects of glycyrrhizin pre-treatment on transient ischemic brain ...

    African Journals Online (AJOL)

    Effects of glycyrrhizin pre-treatment on transient ischemic brain injury in mice. ... on transient ischemic brain injury in mice. Chiyeon Lim, Sehyun Lim, Young-Jun Lee, Bokcheul Kong, Byoungho Lee, Chang-Hyun Kim, Buyeo Kim, Suin Cho ... induced brain damage. Keywords: Glycyrrhizin, licorice, stroke, apoptosis ...

  10. Proceedings – Mathematical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 112; Issue 2. Sums of Two Polynomials with Each having Real Zeros Symmetric with the Other. Seon-Hong Kim. Volume 112 Issue 2 ... Author Affiliations. Seon-Hong Kim1. School of Mathematical Sciences, Seoul National University, Seoul 151-742, Korea ...

  11. Optimized tuning of contention window for IEEE 802.11 WLAN

    African Journals Online (AJOL)

    2, pp.151-70. Bononi L., Marco C., Enrico G. 2004. Runtime optimization of IEEE 802.11 wireless LANs performance.IEEE Transactions on. Parallel and Distributed Systems. Vol. 15, No.1 , pp.66-80. Hong K., Lee S., Kim K., Kim Y. 2012. Channel condition based contention window adaptation in IEEE 802.11 WLANs. IEEE.

  12. Kidney injury molecule-1 in renal disease

    NARCIS (Netherlands)

    Waanders, Femke; van Timmeren, Mirjan M.; Stegeman, Coen A.; Bakker, Stephan J. L.; van Goor, Harry

    Kidney injury molecule-1 (KIM-1) is a marker for renal proximal tubular damage, the hallmark of virtually all proteinuric, toxic and ischaemic kidney diseases. KIM-1 has gained increasing interest because of its possible pathophysiological role in modulating tubular damage and repair. In this

  13. Effect of Renin-Angiotensin-Aidosterone System Inhibition, Dietary Sodium Restriction, and/or Diuretics on Urinary Kidney Injury Molecule 1 Excretion in Nondiabetic Proteinuric Kidney Disease : A Post Hoc Analysis of a Randomized Controlled Trial

    NARCIS (Netherlands)

    Waanders, Femke; Vaidya, Vishal S.; van Goor, Harry; Leuvenink, Henri; Damman, Kevin; Hamming, Inge; Bonventre, Joseph V.; Vogt, Liffert; Navis, Gerjan

    Background: Tubulointerstitial damage plays an important role in chronic kidney disease (CKD) with proteinuria. Urinary kidney injury molecule 1 (KIM-1) reflects tubular KIM-1 and is considered a sensitive biomarker for early tubular damage. We hypothesized that a decrease in proteinuria by using

  14. Meat tenderness and water holding capacity are associated with a ...

    African Journals Online (AJOL)

    Jane

    2011-06-22

    Jun 22, 2011 ... increasing inquires of consumers for meat of high quality. In previous ... carcass traits in cattle have been reported in Korean cattle (Bhuiyan et al., ..... Food Sci. 31(6): 286-292. Bhuiyan MSA, Kim NK, Cho YM, Yoon D, Kim KS, Jeon JT, Lee JH. (2009). Identification of SNPs in MYOD gene family and their.

  15. Institutional Change through Assessment: Contrasting Case Studies

    Science.gov (United States)

    Deess, E. Pierre; Elliot, Norbert

    2009-01-01

    The framework for understanding the management difference is neatly captured by the "red ocean" and "blue ocean" strategies described by W. Chan Kim and Renee Mauborgne in "Blue Ocean Strategy" (Kim & Mauborgne, 2004). In the original, the terms refer to alternative market strategies. Red ocean means competition in a market defined by a zero sum…

  16. Malicious MXit? South African adolescents' use of mobile-based ...

    African Journals Online (AJOL)

    Ongoing debate in psychology literature discusses the notion of compulsive usage of online communication platforms (commonly termed Internet addiction), particularly among adolescents (Kim et al. 2006, Fu et al. 2010, Israelashvili, Kim and Bukobza 2012). Journal of Child & Adolescent Mental Health 2012, 24(2): 117– ...

  17. A basic inequality for submanifolds in locally conformal almost ...

    Indian Academy of Sciences (India)

    Mukut Mani Tripathi1 Jeong-Sik Kim2 Seon-Bu Kim3. Department of Mathematics and Astronomy, Lucknow University, Lucknow 226 007, India; Department of Mathematics Education, Sunchon National University, Sunchon 540-742, Korea; Department of Mathematics, Chonnam National University, Kwangju 500-757, ...

  18. Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (81st, Baltimore, Maryland, August 5-8, 1998). Advertising.

    Science.gov (United States)

    Association for Education in Journalism and Mass Communication.

    The Advertising section of the Proceedings contains the following 18 papers: "The Birth of Adwatches: Political Advertising Becomes Front-Page News" (Jennifer Greer); "A Cross-Cultural Comparison of the Effects of Source Credibility on Attitudes and Behavioral Intentions" (Kak Yoon, Choong Hyun Kim, and Min-Sun Kim);…

  19. MicroRNA Gene Regulatory Networks in Peripheral Nerve Sheath Tumors

    Science.gov (United States)

    2012-09-01

    meeting of the Dutch Society of Nephrology and the Renal Association, Amsterdam, 27–28 October 1989 MicroRNAs in human sarcomas 123 79. Kim WK, Park M, Kim...Thomson JM, Wu Q, Callis TE, Ham - mond SM, Conlon FL, Wang DZ (2006) The role of microRNA- 1 and microRNA-133 in skeletal muscle proliferation and dif

  20. Comparison of in vivo biocompatibilities between parylene-C and ...

    Indian Academy of Sciences (India)

    ... Materials Science; Volume 36; Issue 6. Comparison of in vivo biocompatibilities between parylene-C and polydimethylsiloxane for implantable microelectronic devices. Dong Sup Lee Su Jin Kim Eun Bi Kwon Cheol Whee Park Su Min Jun Bumkyoo Choi Sae Woong Kim. Volume 36 Issue 6 November 2013 pp 1127-1132 ...

  1. We Are Going to Have to Imagine Our Way Out of This One...

    DEFF Research Database (Denmark)

    De Cock, Christian

    2018-01-01

    Book reviews of: New York 2140. Kim Stanley Robinson. London: Orbit, 2017. 624 pp. £20 (hbk). ISBN 9780356508757 Science in the Capital trilogy: Forty Signs of Rain (2004 – ASIN: B01KTJYB5G), Fifty Degrees Below (2005 – ASIN: B00BS06T88), Sixty Days & Counting (2007 – ASIN: B00BS06T8I) – Kim...

  2. Piwi-interacting RNAs (piRNAs) in animals: The story so far

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-01

    Sep 1, 2009 ... germline stem cell maintenance, epigenetic regulation, and transposition. Although the biogenesis pathways of .... somes 2, 4, 5 and 17 but seem to be absent on sex chro- mosomes (Kim, 2006). The piRNAs can ... piRNAs in a given cluster are derived from the same orientation (Kim, 2006). SYNTHESIS ...

  3. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences. JW JAHNG. Articles written in Journal of Biosciences. Volume 42 Issue 1 March 2017 pp 131-138 Article. Early life stress experience may blunt hypothalamic leptin signalling · JH LEE SB YOO JY KIM JY LEE BT KIM K PARK JW JAHNG · More Details Abstract Fulltext PDF. The aim ...

  4. Production parameters of the therapeutic Rh radionuclide using ...

    Indian Academy of Sciences (India)

    243–248. Production parameters of the therapeutic. 105. Rh radionuclide using medium energy cyclotron. MAYEEN UDDIN KHANDAKER1,2,∗. , KWANGSOO KIM2 and. GUINYUN KIM2. 1Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia. 2Department of Physics, Kyungpook National University, ...

  5. Cytotoxicity of yellow sand in lung epithelial cells

    Indian Academy of Sciences (India)

    Y H Kim1 K S Kim1 N J Kwak1 K H Lee1 2 S A Kweon3 Y Lim4. Research Institute of New Drug Development, The Catholic University of Korea, Seoul, Korea; Department of Pharmacology, The Catholic University of Korea, Seoul, Korea; Environment Technology Center, NIER, The Catholic University of Korea, Seoul, Korea ...

  6. Noncommunicating isolated enteric duplication cyst in the abdomen ...

    African Journals Online (AJOL)

    Noncommunicating isolated enteric duplication cyst in the abdomen in children: report of one case and review of the literature. Hyun-Young Kim, Soo-Hong Kim, Kwi-Won Park and Sung-Eun Jung. Noncommunicating isolated enteric duplications in the abdomen are an extremely rare variant of enteric duplications with their ...

  7. Characterization of Bending Magnetostriction in Iron-Gallium Alloys for Nanowire Sensor Applications

    Science.gov (United States)

    2008-01-01

    ferrimagnets and antiferromagnets), which are so named due to iron be- ing the archetype rather than being a necessary element in the composition. In...Varadwaj, Paritosh Mohanty, Sunghun Lee, Younghun Jo, Myung-Hwa Jung , Jinhee Kim, and Bongsoo Kim. Magnetic properties of single-crystalline CoSi nanowires

  8. Effects of various additives to enhance growth performance, blood ...

    African Journals Online (AJOL)

    Effects of various additives to enhance growth performance, blood profiles, and reduce malodour emissions in growing pigs. W.G. Kwak, I.H. Park, W Yun, J.H. Lee, C.H. Lee, S.Y. Oh, H.J. Oh, Shudong Liu, Y.H. Kim, J.C. Park, G.S. Kim, J.H. Cho ...

  9. Expression of porcine myosin heavy chain 1 gene in Berkshire loins ...

    African Journals Online (AJOL)

    Expression of porcine myosin heavy chain 1 gene in Berkshire loins with a high pH24 value. Jin Hun Kang, Woo Young Bang, Eun Jung Kwon, Yong Hwa Lee, Da Hye Park, Eun Seok Cho, Min Ji Kim, Jong-Soon Choi, Hwa Chun Park, Beom Young Park, Chul Wook Kim ...

  10. African Journal of Biotechnology - Vol 11, No 48 (2012)

    African Journals Online (AJOL)

    ... brain aromatase-induction of monosodium glutamate in estrogen-responsive mosaic transgenic zebra fish Danio rerio · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Tamer Said Abdelkader, Chang Seo-Na, Kim Tae-Hyun, Song Juha, Kim Dongso, Jae-Hak Park ...

  11. African Journal of Biotechnology - Vol 11, No 15 (2012)

    African Journals Online (AJOL)

    Comparison of callus induction and plant regenerationfrom twenty tall fescue varieties · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. KW Lee, GJ Choi, KY Kim, HC Ji, HS Park, S Seo, MJ Kim, SH Lee, 3553-3557. http://dx.doi.org/10.5897/AJB11.1578 ...

  12. Effects of different fertilizers on methane emission from paddy field of ...

    African Journals Online (AJOL)

    deltafuture

    paddy filds in Southeast China occur after applying anaerobic digestion slurry. GCB Bioenergy 6:465-472. Kim GY, Gutierrez J, Jeong HC, Lee JS, Haque MM, Kim PJ (2014). Effect of intermittent drainage on methane and nitrous oxide emissions under different fertilization in a temperate paddy soil during rice cultivation.

  13. African Journal of Biotechnology - Vol 11, No 55 (2012)

    African Journals Online (AJOL)

    Effect of dietary mugwort (Artemisia vulgaris L.) and pine needle powder (Pinus densiflora) on growth performance, serum cholesterol levels, and meat quality in broilers · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Y.J Kim, C.M Kim, J.H Choi, I.H Choi, 11998- ...

  14. The signalling of German rising-falling intonation categories--the interplay of synchronization, shape, and height

    DEFF Research Database (Denmark)

    Niebuhr, Oliver

    2007-01-01

    Based on the phonology of the Kiel Intonation Model (KIM), a tripartite opposition of German intonation is investigated: early, medial, and late peaks. These intonation categories, which can be projected onto H + L*, H*, and L* + H in the AM framework, are described in the KIM as rising-falling F...

  15. Aloe Vera

    Science.gov (United States)

    ... month drinking water toxicity study in F344 rats . Food and Chemical Toxicology . 2013;57:21-31. Yang HN, Kim DJ, Kim YM, et al. Aloe-induced toxic hepatitis . Journal of Korean Medical Science. 2010;25(3):492-495. This ...

  16. Selenium acts as an insulin-like molecule for the down-regulation of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 32; Issue 4. Selenium acts as an insulin-like molecule for the down-regulation of diabetic symptoms via endoplasmic reticulum stress and insulin signalling proteins in diabetes-induced non-obese diabetic mice. Daeyoun Hwang Sujin Seo Yongkyu Kim Chuelkyu Kim Sunbo ...

  17. Comparison of callus induction and plant regenerationfrom twenty ...

    African Journals Online (AJOL)

    Comparison of callus induction and plant regenerationfrom twenty tall fescue varieties. KW Lee, GJ Choi, KY Kim, HC Ji, HS Park, S Seo, MJ Kim, SH Lee. Abstract. Tall fescue (Festuca arundinacea Schreb.) is an important grass species both as turf and forage. In this study, 20 varieties of tall fescue were used to investigate ...

  18. Fibrinolysis and anticoagulant potential of a metallo protease ...

    Indian Academy of Sciences (India)

    ), CK (28 kDa) (Kim et al. 1996), DJ-4 (29 kDa) (Kim and Choi 2000) and the fibrinolytic enzyme (31.5 kDa) from a mutant of B. subtilis. IMR-NK1 (Chang et al. 2000), it is likely that the fibrinolytic enzyme from B. subtilis K42 could result in less ...

  19. Two-electron Oxidation of a Twisted Non Anti-aromatic 40π ...

    Indian Academy of Sciences (India)

    PRACHI GUPTA, SANTOSH P PANCHAL and VENKATARAMANARAO G ANAND. ∗. Department of Chemistry ... synthesis of the first twisted 40π expanded isophlorin and also its two-electron oxidation to a 38π dication. It sustains the twisted .... Tanaka T, Aratani N, Lim J M, Kim K S, Kim D and. Osuka A 2011 Chem. Sci.

  20. Frames and extension problems I

    DEFF Research Database (Denmark)

    Christensen, Ole

    2014-01-01

    In this article we present a short survey of frame theory in Hilbert spaces. We discuss Gabor frames and wavelet frames and set the stage for a discussion of various extension principles; this will be presented in the article Frames and extension problems II (joint with H.O. Kim and R.Y. Kim)....